diff options
Diffstat (limited to 'src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_conn.c')
| -rw-r--r-- | src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_conn.c | 13698 |
1 files changed, 13698 insertions, 0 deletions
diff --git a/src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_conn.c b/src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_conn.c new file mode 100644 index 0000000..fb00ca8 --- /dev/null +++ b/src/contrib/libngtcp2/ngtcp2/lib/ngtcp2_conn.c @@ -0,0 +1,13698 @@ +/* + * ngtcp2 + * + * Copyright (c) 2017 ngtcp2 contributors + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ +#include "ngtcp2_conn.h" + +#include <string.h> +#include <assert.h> + +#include "ngtcp2_macro.h" +#include "ngtcp2_log.h" +#include "ngtcp2_cid.h" +#include "ngtcp2_conv.h" +#include "ngtcp2_vec.h" +#include "ngtcp2_addr.h" +#include "ngtcp2_path.h" +#include "ngtcp2_rcvry.h" +#include "ngtcp2_unreachable.h" +#include "ngtcp2_net.h" + +/* NGTCP2_FLOW_WINDOW_RTT_FACTOR is the factor of RTT when flow + control window auto-tuning is triggered. */ +#define NGTCP2_FLOW_WINDOW_RTT_FACTOR 2 +/* NGTCP2_FLOW_WINDOW_SCALING_FACTOR is the growth factor of flow + control window. */ +#define NGTCP2_FLOW_WINDOW_SCALING_FACTOR 2 +/* NGTCP2_MIN_COALESCED_PAYLOADLEN is the minimum length of QUIC + packet payload that should be coalesced to a long packet. */ +#define NGTCP2_MIN_COALESCED_PAYLOADLEN 128 + +/* + * conn_local_stream returns nonzero if |stream_id| indicates that it + * is the stream initiated by local endpoint. + */ +static int conn_local_stream(ngtcp2_conn *conn, int64_t stream_id) { + return (uint8_t)(stream_id & 1) == conn->server; +} + +/* + * bidi_stream returns nonzero if |stream_id| is a bidirectional + * stream ID. + */ +static int bidi_stream(int64_t stream_id) { return (stream_id & 0x2) == 0; } + +/* + * conn_is_handshake_completed returns nonzero if QUIC handshake has + * completed. + */ +static int conn_is_handshake_completed(ngtcp2_conn *conn) { + return (conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED) && + conn->pktns.crypto.rx.ckm && conn->pktns.crypto.tx.ckm; +} + +static int conn_call_recv_client_initial(ngtcp2_conn *conn, + const ngtcp2_cid *dcid) { + int rv; + + assert(conn->callbacks.recv_client_initial); + + rv = conn->callbacks.recv_client_initial(conn, dcid, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_handshake_completed(ngtcp2_conn *conn) { + int rv; + + if (!conn->callbacks.handshake_completed) { + return 0; + } + + rv = conn->callbacks.handshake_completed(conn, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_stream_data(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint32_t flags, uint64_t offset, + const uint8_t *data, size_t datalen) { + int rv; + + if (!conn->callbacks.recv_stream_data) { + return 0; + } + + rv = conn->callbacks.recv_stream_data(conn, flags, strm->stream_id, offset, + data, datalen, conn->user_data, + strm->stream_user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_crypto_data(ngtcp2_conn *conn, + ngtcp2_crypto_level crypto_level, + uint64_t offset, const uint8_t *data, + size_t datalen) { + int rv; + + assert(conn->callbacks.recv_crypto_data); + + rv = conn->callbacks.recv_crypto_data(conn, crypto_level, offset, data, + datalen, conn->user_data); + switch (rv) { + case 0: + case NGTCP2_ERR_CRYPTO: + case NGTCP2_ERR_REQUIRED_TRANSPORT_PARAM: + case NGTCP2_ERR_MALFORMED_TRANSPORT_PARAM: + case NGTCP2_ERR_TRANSPORT_PARAM: + case NGTCP2_ERR_PROTO: + case NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE: + case NGTCP2_ERR_NOMEM: + case NGTCP2_ERR_CALLBACK_FAILURE: + return rv; + default: + return NGTCP2_ERR_CALLBACK_FAILURE; + } +} + +static int conn_call_stream_open(ngtcp2_conn *conn, ngtcp2_strm *strm) { + int rv; + + if (!conn->callbacks.stream_open) { + return 0; + } + + rv = conn->callbacks.stream_open(conn, strm->stream_id, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_stream_close(ngtcp2_conn *conn, ngtcp2_strm *strm) { + int rv; + uint32_t flags = NGTCP2_STREAM_CLOSE_FLAG_NONE; + + if (!conn->callbacks.stream_close) { + return 0; + } + + if (strm->flags & NGTCP2_STRM_FLAG_APP_ERROR_CODE_SET) { + flags |= NGTCP2_STREAM_CLOSE_FLAG_APP_ERROR_CODE_SET; + } + + rv = conn->callbacks.stream_close(conn, flags, strm->stream_id, + strm->app_error_code, conn->user_data, + strm->stream_user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_stream_reset(ngtcp2_conn *conn, int64_t stream_id, + uint64_t final_size, uint64_t app_error_code, + void *stream_user_data) { + int rv; + + if (!conn->callbacks.stream_reset) { + return 0; + } + + rv = conn->callbacks.stream_reset(conn, stream_id, final_size, app_error_code, + conn->user_data, stream_user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_extend_max_local_streams_bidi(ngtcp2_conn *conn, + uint64_t max_streams) { + int rv; + + if (!conn->callbacks.extend_max_local_streams_bidi) { + return 0; + } + + rv = conn->callbacks.extend_max_local_streams_bidi(conn, max_streams, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_extend_max_local_streams_uni(ngtcp2_conn *conn, + uint64_t max_streams) { + int rv; + + if (!conn->callbacks.extend_max_local_streams_uni) { + return 0; + } + + rv = conn->callbacks.extend_max_local_streams_uni(conn, max_streams, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_get_new_connection_id(ngtcp2_conn *conn, ngtcp2_cid *cid, + uint8_t *token, size_t cidlen) { + int rv; + + assert(conn->callbacks.get_new_connection_id); + + rv = conn->callbacks.get_new_connection_id(conn, cid, token, cidlen, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_remove_connection_id(ngtcp2_conn *conn, + const ngtcp2_cid *cid) { + int rv; + + if (!conn->callbacks.remove_connection_id) { + return 0; + } + + rv = conn->callbacks.remove_connection_id(conn, cid, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_path_validation(ngtcp2_conn *conn, const ngtcp2_pv *pv, + ngtcp2_path_validation_result res) { + int rv; + uint32_t flags = NGTCP2_PATH_VALIDATION_FLAG_NONE; + + if (!conn->callbacks.path_validation) { + return 0; + } + + if (pv->flags & NGTCP2_PV_FLAG_PREFERRED_ADDR) { + flags |= NGTCP2_PATH_VALIDATION_FLAG_PREFERRED_ADDR; + } + + rv = conn->callbacks.path_validation(conn, flags, &pv->dcid.ps.path, res, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_select_preferred_addr(ngtcp2_conn *conn, + ngtcp2_path *dest) { + int rv; + + if (!conn->callbacks.select_preferred_addr) { + return 0; + } + + assert(conn->remote.transport_params); + assert(conn->remote.transport_params->preferred_address_present); + + rv = conn->callbacks.select_preferred_addr( + conn, dest, &conn->remote.transport_params->preferred_address, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_extend_max_remote_streams_bidi(ngtcp2_conn *conn, + uint64_t max_streams) { + int rv; + + if (!conn->callbacks.extend_max_remote_streams_bidi) { + return 0; + } + + rv = conn->callbacks.extend_max_remote_streams_bidi(conn, max_streams, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_extend_max_remote_streams_uni(ngtcp2_conn *conn, + uint64_t max_streams) { + int rv; + + if (!conn->callbacks.extend_max_remote_streams_uni) { + return 0; + } + + rv = conn->callbacks.extend_max_remote_streams_uni(conn, max_streams, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_extend_max_stream_data(ngtcp2_conn *conn, + ngtcp2_strm *strm, + int64_t stream_id, + uint64_t datalen) { + int rv; + + if (!conn->callbacks.extend_max_stream_data) { + return 0; + } + + rv = conn->callbacks.extend_max_stream_data( + conn, stream_id, datalen, conn->user_data, strm->stream_user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_dcid_status(ngtcp2_conn *conn, + ngtcp2_connection_id_status_type type, + const ngtcp2_dcid *dcid) { + int rv; + + if (!conn->callbacks.dcid_status) { + return 0; + } + + rv = conn->callbacks.dcid_status( + conn, (int)type, dcid->seq, &dcid->cid, + (dcid->flags & NGTCP2_DCID_FLAG_TOKEN_PRESENT) ? dcid->token : NULL, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_activate_dcid(ngtcp2_conn *conn, const ngtcp2_dcid *dcid) { + return conn_call_dcid_status(conn, NGTCP2_CONNECTION_ID_STATUS_TYPE_ACTIVATE, + dcid); +} + +static int conn_call_deactivate_dcid(ngtcp2_conn *conn, + const ngtcp2_dcid *dcid) { + return conn_call_dcid_status( + conn, NGTCP2_CONNECTION_ID_STATUS_TYPE_DEACTIVATE, dcid); +} + +static int conn_call_stream_stop_sending(ngtcp2_conn *conn, int64_t stream_id, + uint64_t app_error_code, + void *stream_user_data) { + int rv; + + if (!conn->callbacks.stream_stop_sending) { + return 0; + } + + rv = conn->callbacks.stream_stop_sending(conn, stream_id, app_error_code, + conn->user_data, stream_user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static void conn_call_delete_crypto_aead_ctx(ngtcp2_conn *conn, + ngtcp2_crypto_aead_ctx *aead_ctx) { + if (!aead_ctx->native_handle) { + return; + } + + assert(conn->callbacks.delete_crypto_aead_ctx); + + conn->callbacks.delete_crypto_aead_ctx(conn, aead_ctx, conn->user_data); +} + +static void +conn_call_delete_crypto_cipher_ctx(ngtcp2_conn *conn, + ngtcp2_crypto_cipher_ctx *cipher_ctx) { + if (!cipher_ctx->native_handle) { + return; + } + + assert(conn->callbacks.delete_crypto_cipher_ctx); + + conn->callbacks.delete_crypto_cipher_ctx(conn, cipher_ctx, conn->user_data); +} + +static int conn_call_client_initial(ngtcp2_conn *conn) { + int rv; + + assert(conn->callbacks.client_initial); + + rv = conn->callbacks.client_initial(conn, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_get_path_challenge_data(ngtcp2_conn *conn, uint8_t *data) { + int rv; + + assert(conn->callbacks.get_path_challenge_data); + + rv = conn->callbacks.get_path_challenge_data(conn, data, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_version_negotiation(ngtcp2_conn *conn, + const ngtcp2_pkt_hd *hd, + const uint32_t *sv, size_t nsv) { + int rv; + + if (!conn->callbacks.recv_version_negotiation) { + return 0; + } + + rv = conn->callbacks.recv_version_negotiation(conn, hd, sv, nsv, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_retry(ngtcp2_conn *conn, const ngtcp2_pkt_hd *hd) { + int rv; + + assert(conn->callbacks.recv_retry); + + rv = conn->callbacks.recv_retry(conn, hd, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int +conn_call_recv_stateless_reset(ngtcp2_conn *conn, + const ngtcp2_pkt_stateless_reset *sr) { + int rv; + + if (!conn->callbacks.recv_stateless_reset) { + return 0; + } + + rv = conn->callbacks.recv_stateless_reset(conn, sr, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_new_token(ngtcp2_conn *conn, const uint8_t *token, + size_t tokenlen) { + int rv; + + if (!conn->callbacks.recv_new_token) { + return 0; + } + + rv = conn->callbacks.recv_new_token(conn, token, tokenlen, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_handshake_confirmed(ngtcp2_conn *conn) { + int rv; + + if (!conn->callbacks.handshake_confirmed) { + return 0; + } + + rv = conn->callbacks.handshake_confirmed(conn, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_datagram(ngtcp2_conn *conn, + const ngtcp2_datagram *fr) { + const uint8_t *data; + size_t datalen; + int rv; + uint32_t flags = NGTCP2_DATAGRAM_FLAG_NONE; + + if (!conn->callbacks.recv_datagram) { + return 0; + } + + if (fr->datacnt) { + assert(fr->datacnt == 1); + + data = fr->data->base; + datalen = fr->data->len; + } else { + data = NULL; + datalen = 0; + } + + if (!conn_is_handshake_completed(conn)) { + flags |= NGTCP2_DATAGRAM_FLAG_EARLY; + } + + rv = conn->callbacks.recv_datagram(conn, flags, data, datalen, + conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int +conn_call_update_key(ngtcp2_conn *conn, uint8_t *rx_secret, uint8_t *tx_secret, + ngtcp2_crypto_aead_ctx *rx_aead_ctx, uint8_t *rx_iv, + ngtcp2_crypto_aead_ctx *tx_aead_ctx, uint8_t *tx_iv, + const uint8_t *current_rx_secret, + const uint8_t *current_tx_secret, size_t secretlen) { + int rv; + + assert(conn->callbacks.update_key); + + rv = conn->callbacks.update_key( + conn, rx_secret, tx_secret, rx_aead_ctx, rx_iv, tx_aead_ctx, tx_iv, + current_rx_secret, current_tx_secret, secretlen, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_version_negotiation(ngtcp2_conn *conn, uint32_t version, + const ngtcp2_cid *dcid) { + int rv; + + assert(conn->callbacks.version_negotiation); + + rv = + conn->callbacks.version_negotiation(conn, version, dcid, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_rx_key(ngtcp2_conn *conn, ngtcp2_crypto_level level) { + int rv; + + if (!conn->callbacks.recv_rx_key) { + return 0; + } + + rv = conn->callbacks.recv_rx_key(conn, level, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int conn_call_recv_tx_key(ngtcp2_conn *conn, ngtcp2_crypto_level level) { + int rv; + + if (!conn->callbacks.recv_tx_key) { + return 0; + } + + rv = conn->callbacks.recv_tx_key(conn, level, conn->user_data); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +static int crypto_offset_less(const ngtcp2_ksl_key *lhs, + const ngtcp2_ksl_key *rhs) { + return *(int64_t *)lhs < *(int64_t *)rhs; +} + +static int pktns_init(ngtcp2_pktns *pktns, ngtcp2_pktns_id pktns_id, + ngtcp2_rst *rst, ngtcp2_cc *cc, ngtcp2_log *log, + ngtcp2_qlog *qlog, ngtcp2_objalloc *rtb_entry_objalloc, + ngtcp2_objalloc *frc_objalloc, const ngtcp2_mem *mem) { + int rv; + + memset(pktns, 0, sizeof(*pktns)); + + ngtcp2_gaptr_init(&pktns->rx.pngap, mem); + + pktns->tx.last_pkt_num = -1; + pktns->rx.max_pkt_num = -1; + pktns->rx.max_ack_eliciting_pkt_num = -1; + + rv = ngtcp2_acktr_init(&pktns->acktr, log, mem); + if (rv != 0) { + goto fail_acktr_init; + } + + ngtcp2_strm_init(&pktns->crypto.strm, 0, NGTCP2_STRM_FLAG_NONE, 0, 0, NULL, + NULL, mem); + + ngtcp2_ksl_init(&pktns->crypto.tx.frq, crypto_offset_less, sizeof(uint64_t), + mem); + + ngtcp2_rtb_init(&pktns->rtb, pktns_id, &pktns->crypto.strm, rst, cc, log, + qlog, rtb_entry_objalloc, frc_objalloc, mem); + + return 0; + +fail_acktr_init: + ngtcp2_gaptr_free(&pktns->rx.pngap); + + return rv; +} + +static int pktns_new(ngtcp2_pktns **ppktns, ngtcp2_pktns_id pktns_id, + ngtcp2_rst *rst, ngtcp2_cc *cc, ngtcp2_log *log, + ngtcp2_qlog *qlog, ngtcp2_objalloc *rtb_entry_objalloc, + ngtcp2_objalloc *frc_objalloc, const ngtcp2_mem *mem) { + int rv; + + *ppktns = ngtcp2_mem_malloc(mem, sizeof(ngtcp2_pktns)); + if (*ppktns == NULL) { + return NGTCP2_ERR_NOMEM; + } + + rv = pktns_init(*ppktns, pktns_id, rst, cc, log, qlog, rtb_entry_objalloc, + frc_objalloc, mem); + if (rv != 0) { + ngtcp2_mem_free(mem, *ppktns); + } + + return rv; +} + +static int cycle_less(const ngtcp2_pq_entry *lhs, const ngtcp2_pq_entry *rhs) { + ngtcp2_strm *ls = ngtcp2_struct_of(lhs, ngtcp2_strm, pe); + ngtcp2_strm *rs = ngtcp2_struct_of(rhs, ngtcp2_strm, pe); + + if (ls->cycle == rs->cycle) { + return ls->stream_id < rs->stream_id; + } + + return rs->cycle - ls->cycle <= 1; +} + +static void delete_buffed_pkts(ngtcp2_pkt_chain *pc, const ngtcp2_mem *mem) { + ngtcp2_pkt_chain *next; + + for (; pc;) { + next = pc->next; + ngtcp2_pkt_chain_del(pc, mem); + pc = next; + } +} + +static void delete_buf_chain(ngtcp2_buf_chain *bufchain, + const ngtcp2_mem *mem) { + ngtcp2_buf_chain *next; + + for (; bufchain;) { + next = bufchain->next; + ngtcp2_buf_chain_del(bufchain, mem); + bufchain = next; + } +} + +static void pktns_free(ngtcp2_pktns *pktns, const ngtcp2_mem *mem) { + ngtcp2_frame_chain *frc; + ngtcp2_ksl_it it; + + delete_buf_chain(pktns->crypto.tx.data, mem); + + delete_buffed_pkts(pktns->rx.buffed_pkts, mem); + + ngtcp2_frame_chain_list_objalloc_del(pktns->tx.frq, pktns->rtb.frc_objalloc, + mem); + + ngtcp2_crypto_km_del(pktns->crypto.rx.ckm, mem); + ngtcp2_crypto_km_del(pktns->crypto.tx.ckm, mem); + + for (it = ngtcp2_ksl_begin(&pktns->crypto.tx.frq); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + frc = ngtcp2_ksl_it_get(&it); + ngtcp2_frame_chain_objalloc_del(frc, pktns->rtb.frc_objalloc, mem); + } + + ngtcp2_ksl_free(&pktns->crypto.tx.frq); + ngtcp2_rtb_free(&pktns->rtb); + ngtcp2_strm_free(&pktns->crypto.strm); + ngtcp2_acktr_free(&pktns->acktr); + ngtcp2_gaptr_free(&pktns->rx.pngap); +} + +static void pktns_del(ngtcp2_pktns *pktns, const ngtcp2_mem *mem) { + if (pktns == NULL) { + return; + } + + pktns_free(pktns, mem); + + ngtcp2_mem_free(mem, pktns); +} + +static void cc_del(ngtcp2_cc *cc, ngtcp2_cc_algo cc_algo, + const ngtcp2_mem *mem) { + switch (cc_algo) { + case NGTCP2_CC_ALGO_RENO: + ngtcp2_cc_reno_cc_free(cc, mem); + break; + case NGTCP2_CC_ALGO_CUBIC: + ngtcp2_cc_cubic_cc_free(cc, mem); + break; + case NGTCP2_CC_ALGO_BBR: + ngtcp2_cc_bbr_cc_free(cc, mem); + break; + case NGTCP2_CC_ALGO_BBR2: + ngtcp2_cc_bbr2_cc_free(cc, mem); + break; + default: + break; + } +} + +static int cid_less(const ngtcp2_ksl_key *lhs, const ngtcp2_ksl_key *rhs) { + return ngtcp2_cid_less(lhs, rhs); +} + +static int retired_ts_less(const ngtcp2_pq_entry *lhs, + const ngtcp2_pq_entry *rhs) { + const ngtcp2_scid *a = ngtcp2_struct_of(lhs, ngtcp2_scid, pe); + const ngtcp2_scid *b = ngtcp2_struct_of(rhs, ngtcp2_scid, pe); + + return a->retired_ts < b->retired_ts; +} + +/* + * conn_reset_conn_stat_cc resets congestion state in |cstat|. + */ +static void conn_reset_conn_stat_cc(ngtcp2_conn *conn, + ngtcp2_conn_stat *cstat) { + cstat->latest_rtt = 0; + cstat->min_rtt = UINT64_MAX; + cstat->smoothed_rtt = conn->local.settings.initial_rtt; + cstat->rttvar = conn->local.settings.initial_rtt / 2; + cstat->first_rtt_sample_ts = UINT64_MAX; + cstat->pto_count = 0; + cstat->loss_detection_timer = UINT64_MAX; + cstat->cwnd = + ngtcp2_cc_compute_initcwnd(conn->local.settings.max_tx_udp_payload_size); + cstat->ssthresh = UINT64_MAX; + cstat->congestion_recovery_start_ts = UINT64_MAX; + cstat->bytes_in_flight = 0; + cstat->delivery_rate_sec = 0; + cstat->pacing_rate = 0.0; + cstat->send_quantum = 64 * 1024; +} + +/* + * reset_conn_stat_recovery resets the fields related to the recovery + * function + */ +static void reset_conn_stat_recovery(ngtcp2_conn_stat *cstat) { + /* Initializes them with UINT64_MAX. */ + memset(cstat->loss_time, 0xff, sizeof(cstat->loss_time)); + memset(cstat->last_tx_pkt_ts, 0xff, sizeof(cstat->last_tx_pkt_ts)); +} + +/* + * conn_reset_conn_stat resets |cstat|. The following fields are not + * reset: initial_rtt and max_udp_payload_size. + */ +static void conn_reset_conn_stat(ngtcp2_conn *conn, ngtcp2_conn_stat *cstat) { + conn_reset_conn_stat_cc(conn, cstat); + reset_conn_stat_recovery(cstat); +} + +static void delete_scid(ngtcp2_ksl *scids, const ngtcp2_mem *mem) { + ngtcp2_ksl_it it; + + for (it = ngtcp2_ksl_begin(scids); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + ngtcp2_mem_free(mem, ngtcp2_ksl_it_get(&it)); + } +} + +/* + * compute_pto computes PTO. + */ +static ngtcp2_duration compute_pto(ngtcp2_duration smoothed_rtt, + ngtcp2_duration rttvar, + ngtcp2_duration max_ack_delay) { + ngtcp2_duration var = ngtcp2_max(4 * rttvar, NGTCP2_GRANULARITY); + return smoothed_rtt + var + max_ack_delay; +} + +/* + * conn_compute_initial_pto computes PTO using the initial RTT. + */ +static ngtcp2_duration conn_compute_initial_pto(ngtcp2_conn *conn, + ngtcp2_pktns *pktns) { + ngtcp2_duration initial_rtt = conn->local.settings.initial_rtt; + ngtcp2_duration max_ack_delay; + + if (pktns->rtb.pktns_id == NGTCP2_PKTNS_ID_APPLICATION && + conn->remote.transport_params) { + max_ack_delay = conn->remote.transport_params->max_ack_delay; + } else { + max_ack_delay = 0; + } + return compute_pto(initial_rtt, initial_rtt / 2, max_ack_delay); +} + +/* + * conn_compute_pto computes the current PTO. + */ +static ngtcp2_duration conn_compute_pto(ngtcp2_conn *conn, + ngtcp2_pktns *pktns) { + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_duration max_ack_delay; + + if (pktns->rtb.pktns_id == NGTCP2_PKTNS_ID_APPLICATION && + conn->remote.transport_params) { + max_ack_delay = conn->remote.transport_params->max_ack_delay; + } else { + max_ack_delay = 0; + } + return compute_pto(cstat->smoothed_rtt, cstat->rttvar, max_ack_delay); +} + +ngtcp2_duration ngtcp2_conn_compute_pto(ngtcp2_conn *conn, + ngtcp2_pktns *pktns) { + return conn_compute_pto(conn, pktns); +} + +static void conn_handle_tx_ecn(ngtcp2_conn *conn, ngtcp2_pkt_info *pi, + uint16_t *prtb_entry_flags, ngtcp2_pktns *pktns, + const ngtcp2_pkt_hd *hd, ngtcp2_tstamp ts) { + assert(pi); + + if (pi->ecn != NGTCP2_ECN_NOT_ECT) { + /* We have already made a transition of validation state and + deceided to send UDP datagram with ECN bit set. Coalesced QUIC + packets also bear ECN bits set. */ + if (pktns->tx.ecn.start_pkt_num == INT64_MAX) { + pktns->tx.ecn.start_pkt_num = hd->pkt_num; + } + + ++pktns->tx.ecn.validation_pkt_sent; + + if (prtb_entry_flags) { + *prtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ECN; + } + + ++pktns->tx.ecn.ect0; + + return; + } + + switch (conn->tx.ecn.state) { + case NGTCP2_ECN_STATE_TESTING: + if (conn->tx.ecn.validation_start_ts == UINT64_MAX) { + assert(0 == pktns->tx.ecn.validation_pkt_sent); + assert(0 == pktns->tx.ecn.validation_pkt_lost); + + conn->tx.ecn.validation_start_ts = ts; + } else if (ts - conn->tx.ecn.validation_start_ts >= + 3 * conn_compute_pto(conn, pktns)) { + conn->tx.ecn.state = NGTCP2_ECN_STATE_UNKNOWN; + break; + } + + if (pktns->tx.ecn.start_pkt_num == INT64_MAX) { + pktns->tx.ecn.start_pkt_num = hd->pkt_num; + } + + ++pktns->tx.ecn.validation_pkt_sent; + + if (++conn->tx.ecn.dgram_sent == NGTCP2_ECN_MAX_NUM_VALIDATION_PKTS) { + conn->tx.ecn.state = NGTCP2_ECN_STATE_UNKNOWN; + } + /* fall through */ + case NGTCP2_ECN_STATE_CAPABLE: + /* pi is provided per UDP datagram. */ + assert(NGTCP2_ECN_NOT_ECT == pi->ecn); + + pi->ecn = NGTCP2_ECN_ECT_0; + + if (prtb_entry_flags) { + *prtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ECN; + } + + ++pktns->tx.ecn.ect0; + break; + case NGTCP2_ECN_STATE_UNKNOWN: + case NGTCP2_ECN_STATE_FAILED: + break; + default: + ngtcp2_unreachable(); + } +} + +static void conn_reset_ecn_validation_state(ngtcp2_conn *conn) { + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + ngtcp2_pktns *pktns = &conn->pktns; + + conn->tx.ecn.state = NGTCP2_ECN_STATE_TESTING; + conn->tx.ecn.validation_start_ts = UINT64_MAX; + conn->tx.ecn.dgram_sent = 0; + + if (in_pktns) { + in_pktns->tx.ecn.start_pkt_num = INT64_MAX; + in_pktns->tx.ecn.validation_pkt_sent = 0; + in_pktns->tx.ecn.validation_pkt_lost = 0; + } + + if (hs_pktns) { + hs_pktns->tx.ecn.start_pkt_num = INT64_MAX; + hs_pktns->tx.ecn.validation_pkt_sent = 0; + hs_pktns->tx.ecn.validation_pkt_lost = 0; + } + + pktns->tx.ecn.start_pkt_num = INT64_MAX; + pktns->tx.ecn.validation_pkt_sent = 0; + pktns->tx.ecn.validation_pkt_lost = 0; +} + +/* server_default_available_versions is the default available_versions + field sent by server. */ +static uint8_t server_default_available_versions[] = {0, 0, 0, 1}; + +/* + * available_versions_new allocates new buffer, and writes |versions| + * of length |versionslen| in network byte order, suitable for sending + * in available_versions field of version_information QUIC transport + * parameter. The pointer to the allocated buffer is assigned to + * |*pbuf|. + * + * This function returns 0 if it succeeds, or one of the negative + * error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int available_versions_new(uint8_t **pbuf, const uint32_t *versions, + size_t versionslen, const ngtcp2_mem *mem) { + size_t i; + uint8_t *buf = ngtcp2_mem_malloc(mem, sizeof(uint32_t) * versionslen); + + if (buf == NULL) { + return NGTCP2_ERR_NOMEM; + } + + *pbuf = buf; + + for (i = 0; i < versionslen; ++i) { + buf = ngtcp2_put_uint32be(buf, versions[i]); + } + + return 0; +} + +static void +conn_set_local_transport_params(ngtcp2_conn *conn, + const ngtcp2_transport_params *params) { + ngtcp2_transport_params *p = &conn->local.transport_params; + uint32_t chosen_version = p->version_info.chosen_version; + + *p = *params; + + /* grease_quic_bit is always enabled. */ + p->grease_quic_bit = 1; + + if (conn->server) { + p->version_info.chosen_version = chosen_version; + } else { + p->version_info.chosen_version = conn->client_chosen_version; + } + p->version_info.available_versions = conn->vneg.available_versions; + p->version_info.available_versionslen = conn->vneg.available_versionslen; + p->version_info_present = 1; +} + +static int conn_new(ngtcp2_conn **pconn, const ngtcp2_cid *dcid, + const ngtcp2_cid *scid, const ngtcp2_path *path, + uint32_t client_chosen_version, int callbacks_version, + const ngtcp2_callbacks *callbacks, int settings_version, + const ngtcp2_settings *settings, + int transport_params_version, + const ngtcp2_transport_params *params, + const ngtcp2_mem *mem, void *user_data, int server) { + int rv; + ngtcp2_scid *scident; + uint8_t *buf; + uint8_t fixed_bit_byte; + size_t i; + uint32_t *preferred_versions; + (void)callbacks_version; + (void)settings_version; + (void)transport_params_version; + + assert(settings->max_window <= NGTCP2_MAX_VARINT); + assert(settings->max_stream_window <= NGTCP2_MAX_VARINT); + assert(settings->max_tx_udp_payload_size); + assert(settings->max_tx_udp_payload_size <= NGTCP2_HARD_MAX_UDP_PAYLOAD_SIZE); + assert(params->active_connection_id_limit <= NGTCP2_MAX_DCID_POOL_SIZE); + assert(params->initial_max_data <= NGTCP2_MAX_VARINT); + assert(params->initial_max_stream_data_bidi_local <= NGTCP2_MAX_VARINT); + assert(params->initial_max_stream_data_bidi_remote <= NGTCP2_MAX_VARINT); + assert(params->initial_max_stream_data_uni <= NGTCP2_MAX_VARINT); + assert(server || callbacks->client_initial); + assert(!server || callbacks->recv_client_initial); + assert(callbacks->recv_crypto_data); + assert(callbacks->encrypt); + assert(callbacks->decrypt); + assert(callbacks->hp_mask); + assert(server || callbacks->recv_retry); + assert(callbacks->rand); + assert(callbacks->get_new_connection_id); + assert(callbacks->update_key); + assert(callbacks->delete_crypto_aead_ctx); + assert(callbacks->delete_crypto_cipher_ctx); + assert(callbacks->get_path_challenge_data); + assert(!server || !ngtcp2_is_reserved_version(client_chosen_version)); + + if (mem == NULL) { + mem = ngtcp2_mem_default(); + } + + *pconn = ngtcp2_mem_calloc(mem, 1, sizeof(ngtcp2_conn)); + if (*pconn == NULL) { + rv = NGTCP2_ERR_NOMEM; + goto fail_conn; + } + + ngtcp2_objalloc_frame_chain_init(&(*pconn)->frc_objalloc, 64, mem); + ngtcp2_objalloc_rtb_entry_init(&(*pconn)->rtb_entry_objalloc, 64, mem); + ngtcp2_objalloc_strm_init(&(*pconn)->strm_objalloc, 64, mem); + + ngtcp2_static_ringbuf_dcid_bound_init(&(*pconn)->dcid.bound); + + ngtcp2_static_ringbuf_dcid_unused_init(&(*pconn)->dcid.unused); + + ngtcp2_static_ringbuf_dcid_retired_init(&(*pconn)->dcid.retired); + + ngtcp2_gaptr_init(&(*pconn)->dcid.seqgap, mem); + + ngtcp2_ksl_init(&(*pconn)->scid.set, cid_less, sizeof(ngtcp2_cid), mem); + + ngtcp2_pq_init(&(*pconn)->scid.used, retired_ts_less, mem); + + ngtcp2_map_init(&(*pconn)->strms, mem); + + ngtcp2_pq_init(&(*pconn)->tx.strmq, cycle_less, mem); + + ngtcp2_idtr_init(&(*pconn)->remote.bidi.idtr, !server, mem); + + ngtcp2_idtr_init(&(*pconn)->remote.uni.idtr, !server, mem); + + ngtcp2_static_ringbuf_path_challenge_init(&(*pconn)->rx.path_challenge); + + ngtcp2_log_init(&(*pconn)->log, scid, settings->log_printf, + settings->initial_ts, user_data); + ngtcp2_qlog_init(&(*pconn)->qlog, settings->qlog.write, settings->initial_ts, + user_data); + if ((*pconn)->qlog.write) { + buf = ngtcp2_mem_malloc(mem, NGTCP2_QLOG_BUFLEN); + if (buf == NULL) { + rv = NGTCP2_ERR_NOMEM; + goto fail_qlog_buf; + } + ngtcp2_buf_init(&(*pconn)->qlog.buf, buf, NGTCP2_QLOG_BUFLEN); + } + + (*pconn)->local.settings = *settings; + + if (settings->tokenlen) { + buf = ngtcp2_mem_malloc(mem, settings->tokenlen); + if (buf == NULL) { + rv = NGTCP2_ERR_NOMEM; + goto fail_token; + } + memcpy(buf, settings->token, settings->tokenlen); + (*pconn)->local.settings.token = buf; + } else { + (*pconn)->local.settings.token = NULL; + } + + if (!(*pconn)->local.settings.original_version) { + (*pconn)->local.settings.original_version = client_chosen_version; + } + + conn_reset_conn_stat(*pconn, &(*pconn)->cstat); + (*pconn)->cstat.initial_rtt = settings->initial_rtt; + (*pconn)->cstat.max_tx_udp_payload_size = + (*pconn)->local.settings.max_tx_udp_payload_size; + + ngtcp2_rst_init(&(*pconn)->rst); + + (*pconn)->cc_algo = settings->cc_algo; + + switch (settings->cc_algo) { + case NGTCP2_CC_ALGO_RENO: + rv = ngtcp2_cc_reno_cc_init(&(*pconn)->cc, &(*pconn)->log, mem); + if (rv != 0) { + goto fail_cc_init; + } + break; + case NGTCP2_CC_ALGO_CUBIC: + rv = ngtcp2_cc_cubic_cc_init(&(*pconn)->cc, &(*pconn)->log, mem); + if (rv != 0) { + goto fail_cc_init; + } + break; + case NGTCP2_CC_ALGO_BBR: + rv = ngtcp2_cc_bbr_cc_init(&(*pconn)->cc, &(*pconn)->log, &(*pconn)->cstat, + &(*pconn)->rst, settings->initial_ts, + callbacks->rand, &settings->rand_ctx, mem); + if (rv != 0) { + goto fail_cc_init; + } + break; + case NGTCP2_CC_ALGO_BBR2: + rv = ngtcp2_cc_bbr2_cc_init(&(*pconn)->cc, &(*pconn)->log, &(*pconn)->cstat, + &(*pconn)->rst, settings->initial_ts, + callbacks->rand, &settings->rand_ctx, mem); + if (rv != 0) { + goto fail_cc_init; + } + break; + default: + ngtcp2_unreachable(); + } + + rv = pktns_new(&(*pconn)->in_pktns, NGTCP2_PKTNS_ID_INITIAL, &(*pconn)->rst, + &(*pconn)->cc, &(*pconn)->log, &(*pconn)->qlog, + &(*pconn)->rtb_entry_objalloc, &(*pconn)->frc_objalloc, mem); + if (rv != 0) { + goto fail_in_pktns_init; + } + + rv = pktns_new(&(*pconn)->hs_pktns, NGTCP2_PKTNS_ID_HANDSHAKE, &(*pconn)->rst, + &(*pconn)->cc, &(*pconn)->log, &(*pconn)->qlog, + &(*pconn)->rtb_entry_objalloc, &(*pconn)->frc_objalloc, mem); + if (rv != 0) { + goto fail_hs_pktns_init; + } + + rv = pktns_init(&(*pconn)->pktns, NGTCP2_PKTNS_ID_APPLICATION, &(*pconn)->rst, + &(*pconn)->cc, &(*pconn)->log, &(*pconn)->qlog, + &(*pconn)->rtb_entry_objalloc, &(*pconn)->frc_objalloc, mem); + if (rv != 0) { + goto fail_pktns_init; + } + + scident = ngtcp2_mem_malloc(mem, sizeof(*scident)); + if (scident == NULL) { + rv = NGTCP2_ERR_NOMEM; + goto fail_scident; + } + + /* Set stateless reset token later if it is available in the local + transport parameters */ + ngtcp2_scid_init(scident, 0, scid); + + rv = ngtcp2_ksl_insert(&(*pconn)->scid.set, NULL, &scident->cid, scident); + if (rv != 0) { + goto fail_scid_set_insert; + } + + scident = NULL; + + ngtcp2_dcid_init(&(*pconn)->dcid.current, 0, dcid, NULL); + ngtcp2_dcid_set_path(&(*pconn)->dcid.current, path); + + rv = ngtcp2_gaptr_push(&(*pconn)->dcid.seqgap, 0, 1); + if (rv != 0) { + goto fail_seqgap_push; + } + + if (settings->preferred_versionslen) { + if (!server && !ngtcp2_is_reserved_version(client_chosen_version)) { + for (i = 0; i < settings->preferred_versionslen; ++i) { + if (settings->preferred_versions[i] == client_chosen_version) { + break; + } + } + + assert(i < settings->preferred_versionslen); + } + + preferred_versions = ngtcp2_mem_malloc( + mem, sizeof(uint32_t) * settings->preferred_versionslen); + if (preferred_versions == NULL) { + rv = NGTCP2_ERR_NOMEM; + goto fail_preferred_versions; + } + + for (i = 0; i < settings->preferred_versionslen; ++i) { + assert(ngtcp2_is_supported_version(settings->preferred_versions[i])); + + preferred_versions[i] = settings->preferred_versions[i]; + } + + (*pconn)->vneg.preferred_versions = preferred_versions; + (*pconn)->vneg.preferred_versionslen = settings->preferred_versionslen; + } + + if (settings->available_versionslen) { + if (!server && !ngtcp2_is_reserved_version(client_chosen_version)) { + for (i = 0; i < settings->available_versionslen; ++i) { + if (settings->available_versions[i] == client_chosen_version) { + break; + } + } + + assert(i < settings->available_versionslen); + } + + for (i = 0; i < settings->available_versionslen; ++i) { + assert(ngtcp2_is_reserved_version(settings->available_versions[i]) || + ngtcp2_is_supported_version(settings->available_versions[i])); + } + + rv = available_versions_new(&buf, settings->available_versions, + settings->available_versionslen, mem); + if (rv != 0) { + goto fail_available_versions; + } + + (*pconn)->vneg.available_versions = buf; + (*pconn)->vneg.available_versionslen = + sizeof(uint32_t) * settings->available_versionslen; + } else if (server) { + if (settings->preferred_versionslen) { + rv = available_versions_new(&buf, settings->preferred_versions, + settings->preferred_versionslen, mem); + if (rv != 0) { + goto fail_available_versions; + } + + (*pconn)->vneg.available_versions = buf; + (*pconn)->vneg.available_versionslen = + sizeof(uint32_t) * settings->preferred_versionslen; + } else { + (*pconn)->vneg.available_versions = server_default_available_versions; + (*pconn)->vneg.available_versionslen = + sizeof(server_default_available_versions); + } + } else if (!server && !ngtcp2_is_reserved_version(client_chosen_version)) { + rv = available_versions_new(&buf, &client_chosen_version, 1, mem); + if (rv != 0) { + goto fail_available_versions; + } + + (*pconn)->vneg.available_versions = buf; + (*pconn)->vneg.available_versionslen = sizeof(uint32_t); + } + + (*pconn)->client_chosen_version = client_chosen_version; + + conn_set_local_transport_params(*pconn, params); + + callbacks->rand(&fixed_bit_byte, 1, &settings->rand_ctx); + if (fixed_bit_byte & 1) { + (*pconn)->flags |= NGTCP2_CONN_FLAG_CLEAR_FIXED_BIT; + } + + (*pconn)->keep_alive.last_ts = UINT64_MAX; + + (*pconn)->server = server; + (*pconn)->oscid = *scid; + (*pconn)->callbacks = *callbacks; + (*pconn)->mem = mem; + (*pconn)->user_data = user_data; + (*pconn)->idle_ts = settings->initial_ts; + (*pconn)->crypto.key_update.confirmed_ts = UINT64_MAX; + (*pconn)->tx.last_max_data_ts = UINT64_MAX; + (*pconn)->tx.pacing.next_ts = UINT64_MAX; + (*pconn)->early.discard_started_ts = UINT64_MAX; + + conn_reset_ecn_validation_state(*pconn); + + ngtcp2_qlog_start(&(*pconn)->qlog, server ? &settings->qlog.odcid : dcid, + server); + + return 0; + +fail_available_versions: + ngtcp2_mem_free(mem, (*pconn)->vneg.preferred_versions); +fail_preferred_versions: +fail_seqgap_push: +fail_scid_set_insert: + ngtcp2_mem_free(mem, scident); +fail_scident: + pktns_free(&(*pconn)->pktns, mem); +fail_pktns_init: + pktns_del((*pconn)->hs_pktns, mem); +fail_hs_pktns_init: + pktns_del((*pconn)->in_pktns, mem); +fail_in_pktns_init: + cc_del(&(*pconn)->cc, settings->cc_algo, mem); +fail_cc_init: + ngtcp2_mem_free(mem, (uint8_t *)(*pconn)->local.settings.token); +fail_token: + ngtcp2_mem_free(mem, (*pconn)->qlog.buf.begin); +fail_qlog_buf: + ngtcp2_idtr_free(&(*pconn)->remote.uni.idtr); + ngtcp2_idtr_free(&(*pconn)->remote.bidi.idtr); + ngtcp2_map_free(&(*pconn)->strms); + delete_scid(&(*pconn)->scid.set, mem); + ngtcp2_ksl_free(&(*pconn)->scid.set); + ngtcp2_gaptr_free(&(*pconn)->dcid.seqgap); + ngtcp2_objalloc_free(&(*pconn)->strm_objalloc); + ngtcp2_objalloc_free(&(*pconn)->rtb_entry_objalloc); + ngtcp2_objalloc_free(&(*pconn)->frc_objalloc); + ngtcp2_mem_free(mem, *pconn); +fail_conn: + return rv; +} + +int ngtcp2_conn_client_new_versioned( + ngtcp2_conn **pconn, const ngtcp2_cid *dcid, const ngtcp2_cid *scid, + const ngtcp2_path *path, uint32_t client_chosen_version, + int callbacks_version, const ngtcp2_callbacks *callbacks, + int settings_version, const ngtcp2_settings *settings, + int transport_params_version, const ngtcp2_transport_params *params, + const ngtcp2_mem *mem, void *user_data) { + int rv; + + rv = conn_new(pconn, dcid, scid, path, client_chosen_version, + callbacks_version, callbacks, settings_version, settings, + transport_params_version, params, mem, user_data, 0); + if (rv != 0) { + return rv; + } + (*pconn)->rcid = *dcid; + (*pconn)->state = NGTCP2_CS_CLIENT_INITIAL; + (*pconn)->local.bidi.next_stream_id = 0; + (*pconn)->local.uni.next_stream_id = 2; + + rv = ngtcp2_conn_commit_local_transport_params(*pconn); + if (rv != 0) { + ngtcp2_conn_del(*pconn); + return rv; + } + + return 0; +} + +int ngtcp2_conn_server_new_versioned( + ngtcp2_conn **pconn, const ngtcp2_cid *dcid, const ngtcp2_cid *scid, + const ngtcp2_path *path, uint32_t client_chosen_version, + int callbacks_version, const ngtcp2_callbacks *callbacks, + int settings_version, const ngtcp2_settings *settings, + int transport_params_version, const ngtcp2_transport_params *params, + const ngtcp2_mem *mem, void *user_data) { + int rv; + + rv = conn_new(pconn, dcid, scid, path, client_chosen_version, + callbacks_version, callbacks, settings_version, settings, + transport_params_version, params, mem, user_data, 1); + if (rv != 0) { + return rv; + } + + (*pconn)->state = NGTCP2_CS_SERVER_INITIAL; + (*pconn)->local.bidi.next_stream_id = 1; + (*pconn)->local.uni.next_stream_id = 3; + + if ((*pconn)->local.settings.tokenlen) { + /* Usage of token lifts amplification limit */ + (*pconn)->dcid.current.flags |= NGTCP2_DCID_FLAG_PATH_VALIDATED; + } + + return 0; +} + +/* + * conn_fc_credits returns the number of bytes allowed to be sent to + * the given stream. Both connection and stream level flow control + * credits are considered. + */ +static uint64_t conn_fc_credits(ngtcp2_conn *conn, ngtcp2_strm *strm) { + return ngtcp2_min(strm->tx.max_offset - strm->tx.offset, + conn->tx.max_offset - conn->tx.offset); +} + +/* + * conn_enforce_flow_control returns the number of bytes allowed to be + * sent to the given stream. |len| might be shorted because of + * available flow control credits. + */ +static uint64_t conn_enforce_flow_control(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t len) { + uint64_t fc_credits = conn_fc_credits(conn, strm); + return ngtcp2_min(len, fc_credits); +} + +static int delete_strms_each(void *data, void *ptr) { + ngtcp2_conn *conn = ptr; + ngtcp2_strm *s = data; + + ngtcp2_strm_free(s); + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, s); + + return 0; +} + +static void conn_vneg_crypto_free(ngtcp2_conn *conn) { + if (conn->vneg.rx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &conn->vneg.rx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->vneg.rx.hp_ctx); + + if (conn->vneg.tx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &conn->vneg.tx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->vneg.tx.hp_ctx); + + ngtcp2_crypto_km_del(conn->vneg.rx.ckm, conn->mem); + ngtcp2_crypto_km_del(conn->vneg.tx.ckm, conn->mem); +} + +void ngtcp2_conn_del(ngtcp2_conn *conn) { + if (conn == NULL) { + return; + } + + ngtcp2_qlog_end(&conn->qlog); + + if (conn->early.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &conn->early.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->early.hp_ctx); + + if (conn->crypto.key_update.old_rx_ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->crypto.key_update.old_rx_ckm->aead_ctx); + } + if (conn->crypto.key_update.new_rx_ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->crypto.key_update.new_rx_ckm->aead_ctx); + } + if (conn->crypto.key_update.new_tx_ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->crypto.key_update.new_tx_ckm->aead_ctx); + } + + if (conn->pktns.crypto.rx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, + &conn->pktns.crypto.rx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->pktns.crypto.rx.hp_ctx); + + if (conn->pktns.crypto.tx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, + &conn->pktns.crypto.tx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->pktns.crypto.tx.hp_ctx); + + if (conn->hs_pktns) { + if (conn->hs_pktns->crypto.rx.ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->hs_pktns->crypto.rx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->hs_pktns->crypto.rx.hp_ctx); + + if (conn->hs_pktns->crypto.tx.ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->hs_pktns->crypto.tx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->hs_pktns->crypto.tx.hp_ctx); + } + if (conn->in_pktns) { + if (conn->in_pktns->crypto.rx.ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->in_pktns->crypto.rx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->in_pktns->crypto.rx.hp_ctx); + + if (conn->in_pktns->crypto.tx.ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->in_pktns->crypto.tx.ckm->aead_ctx); + } + conn_call_delete_crypto_cipher_ctx(conn, &conn->in_pktns->crypto.tx.hp_ctx); + } + + conn_call_delete_crypto_aead_ctx(conn, &conn->crypto.retry_aead_ctx); + + ngtcp2_transport_params_del(conn->remote.transport_params, conn->mem); + ngtcp2_transport_params_del(conn->remote.pending_transport_params, conn->mem); + + conn_vneg_crypto_free(conn); + + ngtcp2_mem_free(conn->mem, conn->vneg.preferred_versions); + if (conn->vneg.available_versions != server_default_available_versions) { + ngtcp2_mem_free(conn->mem, conn->vneg.available_versions); + } + + ngtcp2_mem_free(conn->mem, conn->crypto.decrypt_buf.base); + ngtcp2_mem_free(conn->mem, conn->crypto.decrypt_hp_buf.base); + ngtcp2_mem_free(conn->mem, (uint8_t *)conn->local.settings.token); + + ngtcp2_crypto_km_del(conn->crypto.key_update.old_rx_ckm, conn->mem); + ngtcp2_crypto_km_del(conn->crypto.key_update.new_rx_ckm, conn->mem); + ngtcp2_crypto_km_del(conn->crypto.key_update.new_tx_ckm, conn->mem); + ngtcp2_crypto_km_del(conn->early.ckm, conn->mem); + + pktns_free(&conn->pktns, conn->mem); + pktns_del(conn->hs_pktns, conn->mem); + pktns_del(conn->in_pktns, conn->mem); + + cc_del(&conn->cc, conn->cc_algo, conn->mem); + + ngtcp2_mem_free(conn->mem, conn->qlog.buf.begin); + + ngtcp2_pmtud_del(conn->pmtud); + ngtcp2_pv_del(conn->pv); + + ngtcp2_mem_free(conn->mem, (uint8_t *)conn->rx.ccerr.reason); + + ngtcp2_idtr_free(&conn->remote.uni.idtr); + ngtcp2_idtr_free(&conn->remote.bidi.idtr); + ngtcp2_mem_free(conn->mem, conn->tx.ack); + ngtcp2_pq_free(&conn->tx.strmq); + ngtcp2_map_each_free(&conn->strms, delete_strms_each, (void *)conn); + ngtcp2_map_free(&conn->strms); + + ngtcp2_pq_free(&conn->scid.used); + delete_scid(&conn->scid.set, conn->mem); + ngtcp2_ksl_free(&conn->scid.set); + ngtcp2_gaptr_free(&conn->dcid.seqgap); + + ngtcp2_objalloc_free(&conn->strm_objalloc); + ngtcp2_objalloc_free(&conn->rtb_entry_objalloc); + ngtcp2_objalloc_free(&conn->frc_objalloc); + + ngtcp2_mem_free(conn->mem, conn); +} + +/* + * conn_ensure_ack_ranges makes sure that conn->tx.ack->ack.ranges can + * contain at least |n| additional ngtcp2_ack_range. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_ensure_ack_ranges(ngtcp2_conn *conn, size_t n) { + ngtcp2_frame *fr; + size_t max = conn->tx.max_ack_ranges; + + if (n <= max) { + return 0; + } + + max *= 2; + + assert(max >= n); + + fr = ngtcp2_mem_realloc(conn->mem, conn->tx.ack, + sizeof(ngtcp2_ack) + sizeof(ngtcp2_ack_range) * max); + if (fr == NULL) { + return NGTCP2_ERR_NOMEM; + } + + conn->tx.ack = fr; + conn->tx.max_ack_ranges = max; + + return 0; +} + +/* + * conn_compute_ack_delay computes ACK delay for outgoing protected + * ACK. + */ +static ngtcp2_duration conn_compute_ack_delay(ngtcp2_conn *conn) { + return ngtcp2_min(conn->local.transport_params.max_ack_delay, + conn->cstat.smoothed_rtt / 8); +} + +/* + * conn_create_ack_frame creates ACK frame, and assigns its pointer to + * |*pfr| if there are any received packets to acknowledge. If there + * are no packets to acknowledge, this function returns 0, and |*pfr| + * is untouched. The caller is advised to set |*pfr| to NULL before + * calling this function, and check it after this function returns. + * If |nodelay| is nonzero, delayed ACK timer is ignored. + * + * The memory for ACK frame is dynamically allocated by this function. + * A caller is responsible to free it. + * + * Call ngtcp2_acktr_commit_ack after a created ACK frame is + * successfully serialized into a packet. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_create_ack_frame(ngtcp2_conn *conn, ngtcp2_frame **pfr, + ngtcp2_pktns *pktns, uint8_t type, + ngtcp2_tstamp ts, ngtcp2_duration ack_delay, + uint64_t ack_delay_exponent) { + /* TODO Measure an actual size of ACK blocks to find the best + default value. */ + const size_t initial_max_ack_ranges = 8; + int64_t last_pkt_num; + ngtcp2_acktr *acktr = &pktns->acktr; + ngtcp2_ack_range *range; + ngtcp2_ksl_it it; + ngtcp2_acktr_entry *rpkt; + ngtcp2_ack *ack; + size_t range_idx; + ngtcp2_tstamp largest_ack_ts; + int rv; + + if (acktr->flags & NGTCP2_ACKTR_FLAG_IMMEDIATE_ACK) { + ack_delay = 0; + } + + if (!ngtcp2_acktr_require_active_ack(acktr, ack_delay, ts)) { + return 0; + } + + it = ngtcp2_acktr_get(acktr); + if (ngtcp2_ksl_it_end(&it)) { + ngtcp2_acktr_commit_ack(acktr); + return 0; + } + + if (conn->tx.ack == NULL) { + conn->tx.ack = ngtcp2_mem_malloc( + conn->mem, + sizeof(ngtcp2_ack) + sizeof(ngtcp2_ack_range) * initial_max_ack_ranges); + if (conn->tx.ack == NULL) { + return NGTCP2_ERR_NOMEM; + } + conn->tx.max_ack_ranges = initial_max_ack_ranges; + } + + ack = &conn->tx.ack->ack; + + if (pktns->rx.ecn.ect0 || pktns->rx.ecn.ect1 || pktns->rx.ecn.ce) { + ack->type = NGTCP2_FRAME_ACK_ECN; + ack->ecn.ect0 = pktns->rx.ecn.ect0; + ack->ecn.ect1 = pktns->rx.ecn.ect1; + ack->ecn.ce = pktns->rx.ecn.ce; + } else { + ack->type = NGTCP2_FRAME_ACK; + } + ack->rangecnt = 0; + + rpkt = ngtcp2_ksl_it_get(&it); + + if (rpkt->pkt_num == pktns->rx.max_pkt_num) { + last_pkt_num = rpkt->pkt_num - (int64_t)(rpkt->len - 1); + largest_ack_ts = rpkt->tstamp; + ack->largest_ack = rpkt->pkt_num; + ack->first_ack_range = rpkt->len - 1; + + ngtcp2_ksl_it_next(&it); + } else { + assert(rpkt->pkt_num < pktns->rx.max_pkt_num); + + last_pkt_num = pktns->rx.max_pkt_num; + largest_ack_ts = pktns->rx.max_pkt_ts; + ack->largest_ack = pktns->rx.max_pkt_num; + ack->first_ack_range = 0; + } + + if (type == NGTCP2_PKT_1RTT) { + ack->ack_delay_unscaled = ts - largest_ack_ts; + ack->ack_delay = ack->ack_delay_unscaled / NGTCP2_MICROSECONDS / + (1ULL << ack_delay_exponent); + } else { + ack->ack_delay_unscaled = 0; + ack->ack_delay = 0; + } + + for (; !ngtcp2_ksl_it_end(&it); ngtcp2_ksl_it_next(&it)) { + if (ack->rangecnt == NGTCP2_MAX_ACK_RANGES) { + break; + } + + rpkt = ngtcp2_ksl_it_get(&it); + + range_idx = ack->rangecnt++; + rv = conn_ensure_ack_ranges(conn, ack->rangecnt); + if (rv != 0) { + return rv; + } + ack = &conn->tx.ack->ack; + range = &ack->ranges[range_idx]; + range->gap = (uint64_t)(last_pkt_num - rpkt->pkt_num - 2); + range->len = rpkt->len - 1; + + last_pkt_num = rpkt->pkt_num - (int64_t)(rpkt->len - 1); + } + + /* TODO Just remove entries which cannot fit into a single ACK frame + for now. */ + if (!ngtcp2_ksl_it_end(&it)) { + ngtcp2_acktr_forget(acktr, ngtcp2_ksl_it_get(&it)); + } + + *pfr = conn->tx.ack; + + return 0; +} + +/* + * conn_ppe_write_frame writes |fr| to |ppe|. If |hd_logged| is not + * NULL and |*hd_logged| is zero, packet header is logged, and 1 is + * assigned to |*hd_logged|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOBUF + * Buffer is too small. + */ +static int conn_ppe_write_frame_hd_log(ngtcp2_conn *conn, ngtcp2_ppe *ppe, + int *hd_logged, const ngtcp2_pkt_hd *hd, + ngtcp2_frame *fr) { + int rv; + + rv = ngtcp2_ppe_encode_frame(ppe, fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return rv; + } + + if (hd_logged && !*hd_logged) { + *hd_logged = 1; + ngtcp2_log_tx_pkt_hd(&conn->log, hd); + ngtcp2_qlog_pkt_sent_start(&conn->qlog); + } + + ngtcp2_log_tx_fr(&conn->log, hd, fr); + ngtcp2_qlog_write_frame(&conn->qlog, fr); + + return 0; +} + +/* + * conn_ppe_write_frame writes |fr| to |ppe|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOBUF + * Buffer is too small. + */ +static int conn_ppe_write_frame(ngtcp2_conn *conn, ngtcp2_ppe *ppe, + const ngtcp2_pkt_hd *hd, ngtcp2_frame *fr) { + return conn_ppe_write_frame_hd_log(conn, ppe, NULL, hd, fr); +} + +/* + * conn_on_pkt_sent is called when new non-ACK-only packet is sent. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + */ +static int conn_on_pkt_sent(ngtcp2_conn *conn, ngtcp2_rtb *rtb, + ngtcp2_rtb_entry *ent) { + int rv; + + /* This function implements OnPacketSent, but it handles only + non-ACK-only packet. */ + rv = ngtcp2_rtb_add(rtb, ent, &conn->cstat); + if (rv != 0) { + return rv; + } + + if (ent->flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) { + conn->cstat.last_tx_pkt_ts[rtb->pktns_id] = ent->ts; + } + + ngtcp2_conn_set_loss_detection_timer(conn, ent->ts); + + return 0; +} + +/* + * pktns_select_pkt_numlen selects shortest packet number encoding for + * the next packet number based on the largest acknowledged packet + * number. It returns the number of bytes to encode the packet + * number. + */ +static size_t pktns_select_pkt_numlen(ngtcp2_pktns *pktns) { + int64_t pkt_num = pktns->tx.last_pkt_num + 1; + ngtcp2_rtb *rtb = &pktns->rtb; + int64_t n = pkt_num - rtb->largest_acked_tx_pkt_num; + + if (NGTCP2_MAX_PKT_NUM / 2 < n) { + return 4; + } + + n = n * 2 - 1; + + if (n > 0xffffff) { + return 4; + } + if (n > 0xffff) { + return 3; + } + if (n > 0xff) { + return 2; + } + return 1; +} + +/* + * conn_get_cwnd returns cwnd for the current path. + */ +static uint64_t conn_get_cwnd(ngtcp2_conn *conn) { + return conn->pv && (conn->pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) + ? ngtcp2_cc_compute_initcwnd(conn->cstat.max_tx_udp_payload_size) + : conn->cstat.cwnd; +} + +/* + * conn_cwnd_is_zero returns nonzero if the number of bytes the local + * endpoint can sent at this time is zero. + */ +static int conn_cwnd_is_zero(ngtcp2_conn *conn) { + uint64_t bytes_in_flight = conn->cstat.bytes_in_flight; + uint64_t cwnd = conn_get_cwnd(conn); + + if (bytes_in_flight >= cwnd) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_RCV, + "cwnd limited bytes_in_flight=%lu cwnd=%lu", + bytes_in_flight, cwnd); + } + + return bytes_in_flight >= cwnd; +} + +/* + * conn_retry_early_payloadlen returns the estimated wire length of + * the first STREAM frame of 0-RTT packet which should be + * retransmitted due to Retry packet. + */ +static uint64_t conn_retry_early_payloadlen(ngtcp2_conn *conn) { + ngtcp2_frame_chain *frc; + ngtcp2_strm *strm; + uint64_t len; + + if (conn->flags & NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED) { + return 0; + } + + for (; !ngtcp2_pq_empty(&conn->tx.strmq);) { + strm = ngtcp2_conn_tx_strmq_top(conn); + if (ngtcp2_strm_streamfrq_empty(strm)) { + ngtcp2_conn_tx_strmq_pop(conn); + continue; + } + + frc = ngtcp2_strm_streamfrq_top(strm); + + len = ngtcp2_vec_len(frc->fr.stream.data, frc->fr.stream.datacnt) + + NGTCP2_STREAM_OVERHEAD; + + /* Take the min because in conn_should_pad_pkt we take max in + order to deal with unbreakable DATAGRAM. */ + return ngtcp2_min(len, NGTCP2_MIN_COALESCED_PAYLOADLEN); + } + + return 0; +} + +static void conn_cryptofrq_clear(ngtcp2_conn *conn, ngtcp2_pktns *pktns) { + ngtcp2_frame_chain *frc; + ngtcp2_ksl_it it; + + for (it = ngtcp2_ksl_begin(&pktns->crypto.tx.frq); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + frc = ngtcp2_ksl_it_get(&it); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + } + ngtcp2_ksl_clear(&pktns->crypto.tx.frq); +} + +/* + * conn_cryptofrq_unacked_offset returns the CRYPTO frame offset by + * taking into account acknowledged offset. If there is no data to + * send, this function returns (uint64_t)-1. + */ +static uint64_t conn_cryptofrq_unacked_offset(ngtcp2_conn *conn, + ngtcp2_pktns *pktns) { + ngtcp2_frame_chain *frc; + ngtcp2_crypto *fr; + ngtcp2_range gap; + ngtcp2_rtb *rtb = &pktns->rtb; + ngtcp2_ksl_it it; + uint64_t datalen; + + (void)conn; + + for (it = ngtcp2_ksl_begin(&pktns->crypto.tx.frq); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + frc = ngtcp2_ksl_it_get(&it); + fr = &frc->fr.crypto; + + gap = ngtcp2_strm_get_unacked_range_after(rtb->crypto, fr->offset); + + datalen = ngtcp2_vec_len(fr->data, fr->datacnt); + + if (gap.begin <= fr->offset) { + return fr->offset; + } + if (gap.begin < fr->offset + datalen) { + return gap.begin; + } + } + + return (uint64_t)-1; +} + +static int conn_cryptofrq_unacked_pop(ngtcp2_conn *conn, ngtcp2_pktns *pktns, + ngtcp2_frame_chain **pfrc) { + ngtcp2_frame_chain *frc, *nfrc; + ngtcp2_crypto *fr, *nfr; + uint64_t offset, end_offset; + size_t idx, end_idx; + uint64_t base_offset, end_base_offset; + ngtcp2_range gap; + ngtcp2_rtb *rtb = &pktns->rtb; + ngtcp2_vec *v; + int rv; + ngtcp2_ksl_it it; + + *pfrc = NULL; + + for (it = ngtcp2_ksl_begin(&pktns->crypto.tx.frq); !ngtcp2_ksl_it_end(&it);) { + frc = ngtcp2_ksl_it_get(&it); + fr = &frc->fr.crypto; + + ngtcp2_ksl_remove_hint(&pktns->crypto.tx.frq, &it, &it, &fr->offset); + + idx = 0; + offset = fr->offset; + base_offset = 0; + + gap = ngtcp2_strm_get_unacked_range_after(rtb->crypto, offset); + if (gap.begin < offset) { + gap.begin = offset; + } + + for (; idx < fr->datacnt && offset < gap.begin; ++idx) { + v = &fr->data[idx]; + if (offset + v->len > gap.begin) { + base_offset = gap.begin - offset; + break; + } + + offset += v->len; + } + + if (idx == fr->datacnt) { + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + + assert(gap.begin == offset + base_offset); + + end_idx = idx; + end_offset = offset; + end_base_offset = 0; + + for (; end_idx < fr->datacnt; ++end_idx) { + v = &fr->data[end_idx]; + if (end_offset + v->len > gap.end) { + end_base_offset = gap.end - end_offset; + break; + } + + end_offset += v->len; + } + + if (fr->offset == offset && base_offset == 0 && fr->datacnt == end_idx) { + *pfrc = frc; + return 0; + } + + if (fr->datacnt == end_idx) { + memmove(fr->data, fr->data + idx, sizeof(fr->data[0]) * (end_idx - idx)); + + assert(fr->data[0].len > base_offset); + + fr->offset = offset + base_offset; + fr->datacnt = end_idx - idx; + fr->data[0].base += base_offset; + fr->data[0].len -= (size_t)base_offset; + + *pfrc = frc; + return 0; + } + + rv = ngtcp2_frame_chain_crypto_datacnt_objalloc_new( + &nfrc, fr->datacnt - end_idx, &conn->frc_objalloc, conn->mem); + if (rv != 0) { + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + nfr = &nfrc->fr.crypto; + nfr->type = NGTCP2_FRAME_CRYPTO; + memcpy(nfr->data, fr->data + end_idx, + sizeof(nfr->data[0]) * (fr->datacnt - end_idx)); + + assert(nfr->data[0].len > end_base_offset); + + nfr->offset = end_offset + end_base_offset; + nfr->datacnt = fr->datacnt - end_idx; + nfr->data[0].base += end_base_offset; + nfr->data[0].len -= (size_t)end_base_offset; + + rv = ngtcp2_ksl_insert(&pktns->crypto.tx.frq, NULL, &nfr->offset, nfrc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(nfrc, &conn->frc_objalloc, conn->mem); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + if (end_base_offset) { + ++end_idx; + } + + memmove(fr->data, fr->data + idx, sizeof(fr->data[0]) * (end_idx - idx)); + + assert(fr->data[0].len > base_offset); + + fr->offset = offset + base_offset; + fr->datacnt = end_idx - idx; + if (end_base_offset) { + assert(fr->data[fr->datacnt - 1].len > end_base_offset); + fr->data[fr->datacnt - 1].len = (size_t)end_base_offset; + } + fr->data[0].base += base_offset; + fr->data[0].len -= (size_t)base_offset; + + *pfrc = frc; + return 0; + } + + return 0; +} +static int conn_cryptofrq_pop(ngtcp2_conn *conn, ngtcp2_frame_chain **pfrc, + ngtcp2_pktns *pktns, size_t left) { + ngtcp2_crypto *fr, *nfr; + ngtcp2_frame_chain *frc, *nfrc; + int rv; + size_t nmerged; + uint64_t datalen; + ngtcp2_vec a[NGTCP2_MAX_CRYPTO_DATACNT]; + ngtcp2_vec b[NGTCP2_MAX_CRYPTO_DATACNT]; + size_t acnt, bcnt; + ngtcp2_ksl_it it; + + rv = conn_cryptofrq_unacked_pop(conn, pktns, &frc); + if (rv != 0) { + return rv; + } + if (frc == NULL) { + *pfrc = NULL; + return 0; + } + + fr = &frc->fr.crypto; + datalen = ngtcp2_vec_len(fr->data, fr->datacnt); + + if (datalen > left) { + ngtcp2_vec_copy(a, fr->data, fr->datacnt); + acnt = fr->datacnt; + + bcnt = 0; + ngtcp2_vec_split(a, &acnt, b, &bcnt, left, NGTCP2_MAX_CRYPTO_DATACNT); + + assert(acnt > 0); + assert(bcnt > 0); + + rv = ngtcp2_frame_chain_crypto_datacnt_objalloc_new( + &nfrc, bcnt, &conn->frc_objalloc, conn->mem); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + nfr = &nfrc->fr.crypto; + nfr->type = NGTCP2_FRAME_CRYPTO; + nfr->offset = fr->offset + left; + nfr->datacnt = bcnt; + ngtcp2_vec_copy(nfr->data, b, bcnt); + + rv = ngtcp2_ksl_insert(&pktns->crypto.tx.frq, NULL, &nfr->offset, nfrc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(nfrc, &conn->frc_objalloc, conn->mem); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + rv = ngtcp2_frame_chain_crypto_datacnt_objalloc_new( + &nfrc, acnt, &conn->frc_objalloc, conn->mem); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + nfr = &nfrc->fr.crypto; + *nfr = *fr; + nfr->datacnt = acnt; + ngtcp2_vec_copy(nfr->data, a, acnt); + + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + + *pfrc = nfrc; + + return 0; + } + + left -= (size_t)datalen; + + ngtcp2_vec_copy(a, fr->data, fr->datacnt); + acnt = fr->datacnt; + + for (; left && ngtcp2_ksl_len(&pktns->crypto.tx.frq);) { + it = ngtcp2_ksl_begin(&pktns->crypto.tx.frq); + nfrc = ngtcp2_ksl_it_get(&it); + nfr = &nfrc->fr.crypto; + + if (nfr->offset != fr->offset + datalen) { + assert(fr->offset + datalen < nfr->offset); + break; + } + + rv = conn_cryptofrq_unacked_pop(conn, pktns, &nfrc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + if (nfrc == NULL) { + break; + } + + nfr = &nfrc->fr.crypto; + + nmerged = ngtcp2_vec_merge(a, &acnt, nfr->data, &nfr->datacnt, left, + NGTCP2_MAX_CRYPTO_DATACNT); + if (nmerged == 0) { + rv = ngtcp2_ksl_insert(&pktns->crypto.tx.frq, NULL, &nfr->offset, nfrc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(nfrc, &conn->frc_objalloc, conn->mem); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + break; + } + + datalen += nmerged; + left -= nmerged; + + if (nfr->datacnt == 0) { + ngtcp2_frame_chain_objalloc_del(nfrc, &conn->frc_objalloc, conn->mem); + continue; + } + + nfr->offset += nmerged; + + rv = ngtcp2_ksl_insert(&pktns->crypto.tx.frq, NULL, &nfr->offset, nfrc); + if (rv != 0) { + ngtcp2_frame_chain_objalloc_del(nfrc, &conn->frc_objalloc, conn->mem); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + break; + } + + if (acnt == fr->datacnt) { + assert(acnt > 0); + fr->data[acnt - 1] = a[acnt - 1]; + + *pfrc = frc; + return 0; + } + + assert(acnt > fr->datacnt); + + rv = ngtcp2_frame_chain_crypto_datacnt_objalloc_new( + &nfrc, acnt, &conn->frc_objalloc, conn->mem); + if (rv != 0) { + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + nfr = &nfrc->fr.crypto; + *nfr = *fr; + nfr->datacnt = acnt; + ngtcp2_vec_copy(nfr->data, a, acnt); + + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + + *pfrc = nfrc; + + return 0; +} + +/* + * conn_verify_dcid verifies that destination connection ID in |hd| is + * valid for the connection. If it is successfully verified and the + * remote endpoint uses new DCID in the packet, nonzero value is + * assigned to |*pnew_cid_used| if it is not NULL. Otherwise 0 is + * assigned to it. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_INVALID_ARGUMENT + * |dcid| is not known to the local endpoint. + */ +static int conn_verify_dcid(ngtcp2_conn *conn, int *pnew_cid_used, + const ngtcp2_pkt_hd *hd) { + ngtcp2_ksl_it it; + ngtcp2_scid *scid; + int rv; + + it = ngtcp2_ksl_lower_bound(&conn->scid.set, &hd->dcid); + if (ngtcp2_ksl_it_end(&it)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + scid = ngtcp2_ksl_it_get(&it); + if (!ngtcp2_cid_eq(&scid->cid, &hd->dcid)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + if (!(scid->flags & NGTCP2_SCID_FLAG_USED)) { + scid->flags |= NGTCP2_SCID_FLAG_USED; + + if (scid->pe.index == NGTCP2_PQ_BAD_INDEX) { + rv = ngtcp2_pq_push(&conn->scid.used, &scid->pe); + if (rv != 0) { + return rv; + } + } + + if (pnew_cid_used) { + *pnew_cid_used = 1; + } + } else if (pnew_cid_used) { + *pnew_cid_used = 0; + } + + return 0; +} + +/* + * conn_should_pad_pkt returns nonzero if the packet should be padded. + * |type| is the type of packet. |left| is the space left in packet + * buffer. |write_datalen| is the number of bytes which will be sent + * in the next, coalesced 0-RTT or 1RTT packet. + */ +static int conn_should_pad_pkt(ngtcp2_conn *conn, uint8_t type, size_t left, + uint64_t write_datalen, int ack_eliciting, + int require_padding) { + uint64_t min_payloadlen; + + if (type == NGTCP2_PKT_INITIAL) { + if (conn->server) { + if (!ack_eliciting) { + return 0; + } + + if (conn->hs_pktns->crypto.tx.ckm && + (conn->hs_pktns->rtb.probe_pkt_left || + ngtcp2_ksl_len(&conn->hs_pktns->crypto.tx.frq) || + !ngtcp2_acktr_empty(&conn->hs_pktns->acktr))) { + /* If we have something to send in Handshake packet, then add + PADDING in Handshake packet. */ + min_payloadlen = NGTCP2_MIN_COALESCED_PAYLOADLEN; + } else { + return 1; + } + } else { + if (conn->hs_pktns->crypto.tx.ckm && + (conn->hs_pktns->rtb.probe_pkt_left || + ngtcp2_ksl_len(&conn->hs_pktns->crypto.tx.frq) || + !ngtcp2_acktr_empty(&conn->hs_pktns->acktr))) { + /* If we have something to send in Handshake packet, then add + PADDING in Handshake packet. */ + min_payloadlen = NGTCP2_MIN_COALESCED_PAYLOADLEN; + } else if ((!conn->early.ckm && !conn->pktns.crypto.tx.ckm) || + write_datalen == 0) { + return 1; + } else { + /* If we have something to send in 0RTT or 1RTT packet, then + add PADDING in that packet. Take maximum in case that + write_datalen includes DATAGRAM which cannot be split. */ + min_payloadlen = + ngtcp2_max(write_datalen, NGTCP2_MIN_COALESCED_PAYLOADLEN); + } + } + } else { + assert(type == NGTCP2_PKT_HANDSHAKE); + + if (!require_padding) { + return 0; + } + + if (!conn->pktns.crypto.tx.ckm || write_datalen == 0) { + return 1; + } + + min_payloadlen = ngtcp2_max(write_datalen, NGTCP2_MIN_COALESCED_PAYLOADLEN); + } + + /* TODO the next packet type should be taken into account */ + return left < + /* TODO Assuming that pkt_num is encoded in 1 byte. */ + NGTCP2_MIN_LONG_HEADERLEN + conn->dcid.current.cid.datalen + + conn->oscid.datalen + NGTCP2_PKT_LENGTHLEN - 1 + min_payloadlen + + NGTCP2_MAX_AEAD_OVERHEAD; +} + +static void conn_restart_timer_on_write(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + conn->idle_ts = ts; + conn->flags &= (uint32_t)~NGTCP2_CONN_FLAG_RESTART_IDLE_TIMER_ON_WRITE; +} + +static void conn_restart_timer_on_read(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + conn->idle_ts = ts; + conn->flags |= NGTCP2_CONN_FLAG_RESTART_IDLE_TIMER_ON_WRITE; +} + +/* + * conn_keep_alive_enabled returns nonzero if keep-alive is enabled. + */ +static int conn_keep_alive_enabled(ngtcp2_conn *conn) { + return conn->keep_alive.last_ts != UINT64_MAX && conn->keep_alive.timeout; +} + +/* + * conn_keep_alive_expired returns nonzero if keep-alive timer has + * expired. + */ +static int conn_keep_alive_expired(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + return conn_keep_alive_enabled(conn) && + conn->keep_alive.last_ts + conn->keep_alive.timeout <= ts; +} + +/* + * conn_keep_alive_expiry returns the expiry time of keep-alive timer. + */ +static ngtcp2_tstamp conn_keep_alive_expiry(ngtcp2_conn *conn) { + if ((conn->flags & NGTCP2_CONN_FLAG_KEEP_ALIVE_CANCELLED) || + !conn_keep_alive_enabled(conn)) { + return UINT64_MAX; + } + + return conn->keep_alive.last_ts + conn->keep_alive.timeout; +} + +/* + * conn_cancel_expired_keep_alive_timer cancels the expired keep-alive + * timer. + */ +static void conn_cancel_expired_keep_alive_timer(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + if (!(conn->flags & NGTCP2_CONN_FLAG_KEEP_ALIVE_CANCELLED) && + conn_keep_alive_expired(conn, ts)) { + conn->flags |= NGTCP2_CONN_FLAG_KEEP_ALIVE_CANCELLED; + } +} + +/* + * conn_update_keep_alive_last_ts updates the base time point of + * keep-alive timer. + */ +static void conn_update_keep_alive_last_ts(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + conn->keep_alive.last_ts = ts; + conn->flags &= (uint32_t)~NGTCP2_CONN_FLAG_KEEP_ALIVE_CANCELLED; +} + +void ngtcp2_conn_set_keep_alive_timeout(ngtcp2_conn *conn, + ngtcp2_duration timeout) { + conn->keep_alive.timeout = timeout; +} + +/* + * NGTCP2_PKT_PACING_OVERHEAD defines overhead of userspace event + * loop. Packet pacing might require sub milliseconds packet spacing, + * but userspace event loop might not offer such precision. + * Typically, if delay is 0.5 microseconds, the actual delay after + * which we can send packet is well over 1 millisecond when event loop + * is involved (which includes other stuff, like reading packets etc + * in a typical single threaded use case). + */ +#define NGTCP2_PKT_PACING_OVERHEAD NGTCP2_MILLISECONDS + +static void conn_cancel_expired_pkt_tx_timer(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + if (conn->tx.pacing.next_ts == UINT64_MAX) { + return; + } + + if (conn->tx.pacing.next_ts > ts + NGTCP2_PKT_PACING_OVERHEAD) { + return; + } + + conn->tx.pacing.next_ts = UINT64_MAX; +} + +static int conn_pacing_pkt_tx_allowed(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + return conn->tx.pacing.next_ts == UINT64_MAX || + conn->tx.pacing.next_ts <= ts + NGTCP2_PKT_PACING_OVERHEAD; +} + +static uint8_t conn_pkt_flags(ngtcp2_conn *conn) { + if (conn->remote.transport_params && + conn->remote.transport_params->grease_quic_bit && + (conn->flags & NGTCP2_CONN_FLAG_CLEAR_FIXED_BIT)) { + return NGTCP2_PKT_FLAG_FIXED_BIT_CLEAR; + } + + return NGTCP2_PKT_FLAG_NONE; +} + +static uint8_t conn_pkt_flags_long(ngtcp2_conn *conn) { + return NGTCP2_PKT_FLAG_LONG_FORM | conn_pkt_flags(conn); +} + +static uint8_t conn_pkt_flags_short(ngtcp2_conn *conn) { + return (uint8_t)(conn_pkt_flags(conn) | ((conn->pktns.crypto.tx.ckm->flags & + NGTCP2_CRYPTO_KM_FLAG_KEY_PHASE_ONE) + ? NGTCP2_PKT_FLAG_KEY_PHASE + : NGTCP2_PKT_FLAG_NONE)); +} + +/* + * conn_write_handshake_pkt writes handshake packet in the buffer + * pointed by |dest| whose length is |destlen|. |type| specifies long + * packet type. It should be either NGTCP2_PKT_INITIAL or + * NGTCP2_PKT_HANDSHAKE_PKT. + * + * |write_datalen| is the minimum length of application data ready to + * send in subsequent 0RTT or 1RTT packet. + * + * This function returns the number of bytes written in |dest| if it + * succeeds, or one of the following negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static ngtcp2_ssize +conn_write_handshake_pkt(ngtcp2_conn *conn, ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, uint8_t type, uint8_t flags, + uint64_t write_datalen, ngtcp2_tstamp ts) { + int rv; + ngtcp2_ppe ppe; + ngtcp2_pkt_hd hd; + ngtcp2_frame_chain *frq = NULL, **pfrc = &frq; + ngtcp2_frame_chain *nfrc; + ngtcp2_frame *ackfr = NULL, lfr; + ngtcp2_ssize spktlen; + ngtcp2_crypto_cc cc; + ngtcp2_rtb_entry *rtbent; + ngtcp2_pktns *pktns; + size_t left; + uint16_t rtb_entry_flags = NGTCP2_RTB_ENTRY_FLAG_NONE; + int require_padding = (flags & NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING) != 0; + int pkt_empty = 1; + int padded = 0; + int hd_logged = 0; + uint64_t crypto_offset; + ngtcp2_ssize num_reclaimed; + uint32_t version; + + switch (type) { + case NGTCP2_PKT_INITIAL: + if (!conn->in_pktns) { + return 0; + } + assert(conn->in_pktns->crypto.tx.ckm); + pktns = conn->in_pktns; + version = conn->negotiated_version ? conn->negotiated_version + : conn->client_chosen_version; + if (version == conn->client_chosen_version) { + cc.ckm = pktns->crypto.tx.ckm; + cc.hp_ctx = pktns->crypto.tx.hp_ctx; + } else { + assert(conn->vneg.version == version); + + cc.ckm = conn->vneg.tx.ckm; + cc.hp_ctx = conn->vneg.tx.hp_ctx; + } + break; + case NGTCP2_PKT_HANDSHAKE: + if (!conn->hs_pktns || !conn->hs_pktns->crypto.tx.ckm) { + return 0; + } + pktns = conn->hs_pktns; + version = conn->negotiated_version; + cc.ckm = pktns->crypto.tx.ckm; + cc.hp_ctx = pktns->crypto.tx.hp_ctx; + break; + default: + ngtcp2_unreachable(); + } + + cc.aead = pktns->crypto.ctx.aead; + cc.hp = pktns->crypto.ctx.hp; + cc.encrypt = conn->callbacks.encrypt; + cc.hp_mask = conn->callbacks.hp_mask; + + ngtcp2_pkt_hd_init(&hd, conn_pkt_flags_long(conn), type, + &conn->dcid.current.cid, &conn->oscid, + pktns->tx.last_pkt_num + 1, pktns_select_pkt_numlen(pktns), + version, 0); + + if (!conn->server && type == NGTCP2_PKT_INITIAL && + conn->local.settings.tokenlen) { + hd.token = conn->local.settings.token; + hd.tokenlen = conn->local.settings.tokenlen; + } + + ngtcp2_ppe_init(&ppe, dest, destlen, &cc); + + rv = ngtcp2_ppe_encode_hd(&ppe, &hd); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return 0; + } + + if (!ngtcp2_ppe_ensure_hp_sample(&ppe)) { + return 0; + } + + rv = conn_create_ack_frame(conn, &ackfr, pktns, type, ts, + /* ack_delay = */ 0, + NGTCP2_DEFAULT_ACK_DELAY_EXPONENT); + if (rv != 0) { + ngtcp2_frame_chain_list_objalloc_del(frq, &conn->frc_objalloc, conn->mem); + return rv; + } + + if (ackfr) { + rv = conn_ppe_write_frame_hd_log(conn, &ppe, &hd_logged, &hd, ackfr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + } else { + ngtcp2_acktr_commit_ack(&pktns->acktr); + ngtcp2_acktr_add_ack(&pktns->acktr, hd.pkt_num, ackfr->ack.largest_ack); + pkt_empty = 0; + } + } + + /* Server requires at least NGTCP2_MAX_UDP_PAYLOAD_SIZE bytes in + order to send ack-eliciting Initial packet. */ + if (!conn->server || type != NGTCP2_PKT_INITIAL || + destlen >= NGTCP2_MAX_UDP_PAYLOAD_SIZE) { + build_pkt: + for (; ngtcp2_ksl_len(&pktns->crypto.tx.frq);) { + left = ngtcp2_ppe_left(&ppe); + + crypto_offset = conn_cryptofrq_unacked_offset(conn, pktns); + if (crypto_offset == (size_t)-1) { + conn_cryptofrq_clear(conn, pktns); + break; + } + + left = ngtcp2_pkt_crypto_max_datalen(crypto_offset, left, left); + if (left == (size_t)-1) { + break; + } + + rv = conn_cryptofrq_pop(conn, &nfrc, pktns, left); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_list_objalloc_del(frq, &conn->frc_objalloc, + conn->mem); + return rv; + } + + if (nfrc == NULL) { + break; + } + + rv = conn_ppe_write_frame_hd_log(conn, &ppe, &hd_logged, &hd, &nfrc->fr); + if (rv != 0) { + ngtcp2_unreachable(); + } + + *pfrc = nfrc; + pfrc = &(*pfrc)->next; + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + } + + if (!(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) && + pktns->rtb.num_retransmittable && pktns->rtb.probe_pkt_left) { + num_reclaimed = ngtcp2_rtb_reclaim_on_pto(&pktns->rtb, conn, pktns, 1); + if (num_reclaimed < 0) { + ngtcp2_frame_chain_list_objalloc_del(frq, &conn->frc_objalloc, + conn->mem); + return rv; + } + if (num_reclaimed) { + goto build_pkt; + } + /* We had pktns->rtb.num_retransmittable > 0 but the contents of + those packets have been acknowledged (i.e., retransmission in + another packet). For server, in this case, we don't have to + send any probe packet. Client needs to send probe packets + until it knows that server has completed address validation or + handshake has been confirmed. */ + if (pktns->rtb.num_pto_eliciting == 0 && + (conn->server || + (conn->flags & (NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED | + NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED)))) { + pktns->rtb.probe_pkt_left = 0; + ngtcp2_conn_set_loss_detection_timer(conn, ts); + /* TODO If packet is empty, we should return now if cwnd is + zero. */ + } + } + + if (!(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) && + pktns->rtb.probe_pkt_left) { + lfr.type = NGTCP2_FRAME_PING; + + rv = conn_ppe_write_frame_hd_log(conn, &ppe, &hd_logged, &hd, &lfr); + if (rv != 0) { + assert(rv == NGTCP2_ERR_NOBUF); + } else { + rtb_entry_flags |= + NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | NGTCP2_RTB_ENTRY_FLAG_PROBE; + pkt_empty = 0; + } + } + + if (!pkt_empty) { + if (!(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING)) { + /* The intention of smaller limit is get more chance to measure + RTT samples in early phase. */ + if (pktns->tx.num_non_ack_pkt >= 1) { + lfr.type = NGTCP2_FRAME_PING; + + rv = conn_ppe_write_frame_hd_log(conn, &ppe, &hd_logged, &hd, &lfr); + if (rv != 0) { + assert(rv == NGTCP2_ERR_NOBUF); + } else { + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING; + pktns->tx.num_non_ack_pkt = 0; + } + } else { + ++pktns->tx.num_non_ack_pkt; + } + } else { + pktns->tx.num_non_ack_pkt = 0; + } + } + } + + if (pkt_empty) { + return 0; + } + + /* If we cannot write another packet, then we need to add padding to + Initial here. */ + if (conn_should_pad_pkt( + conn, type, ngtcp2_ppe_left(&ppe), write_datalen, + (rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) != 0, + require_padding)) { + lfr.type = NGTCP2_FRAME_PADDING; + lfr.padding.len = ngtcp2_ppe_padding(&ppe); + } else { + lfr.type = NGTCP2_FRAME_PADDING; + lfr.padding.len = ngtcp2_ppe_padding_hp_sample(&ppe); + } + + if (lfr.padding.len) { + padded = 1; + ngtcp2_log_tx_fr(&conn->log, &hd, &lfr); + ngtcp2_qlog_write_frame(&conn->qlog, &lfr); + } + + spktlen = ngtcp2_ppe_final(&ppe, NULL); + if (spktlen < 0) { + assert(ngtcp2_err_is_fatal((int)spktlen)); + ngtcp2_frame_chain_list_objalloc_del(frq, &conn->frc_objalloc, conn->mem); + return spktlen; + } + + ngtcp2_qlog_pkt_sent_end(&conn->qlog, &hd, (size_t)spktlen); + + if ((rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) || padded) { + if (pi) { + conn_handle_tx_ecn(conn, pi, &rtb_entry_flags, pktns, &hd, ts); + } + + rv = ngtcp2_rtb_entry_objalloc_new(&rtbent, &hd, frq, ts, (size_t)spktlen, + rtb_entry_flags, + &conn->rtb_entry_objalloc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_list_objalloc_del(frq, &conn->frc_objalloc, conn->mem); + return rv; + } + + rv = conn_on_pkt_sent(conn, &pktns->rtb, rtbent); + if (rv != 0) { + ngtcp2_rtb_entry_objalloc_del(rtbent, &conn->rtb_entry_objalloc, + &conn->frc_objalloc, conn->mem); + return rv; + } + + if ((rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) && + (conn->flags & NGTCP2_CONN_FLAG_RESTART_IDLE_TIMER_ON_WRITE)) { + conn_restart_timer_on_write(conn, ts); + } + } else if (pi && conn->tx.ecn.state == NGTCP2_ECN_STATE_CAPABLE) { + conn_handle_tx_ecn(conn, pi, NULL, pktns, &hd, ts); + } + + if (pktns->rtb.probe_pkt_left && + (rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING)) { + --pktns->rtb.probe_pkt_left; + } + + conn_update_keep_alive_last_ts(conn, ts); + + conn->dcid.current.bytes_sent += (uint64_t)spktlen; + + conn->tx.pacing.pktlen += (size_t)spktlen; + + ngtcp2_qlog_metrics_updated(&conn->qlog, &conn->cstat); + + ++pktns->tx.last_pkt_num; + + return spktlen; +} + +/* + * conn_write_ack_pkt writes QUIC packet for type |type| which only + * includes ACK frame in the buffer pointed by |dest| whose length is + * |destlen|. + * + * This function returns the number of bytes written in |dest| if it + * succeeds, or one of the following negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static ngtcp2_ssize conn_write_ack_pkt(ngtcp2_conn *conn, ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + uint8_t type, ngtcp2_tstamp ts) { + int rv; + ngtcp2_frame *ackfr; + ngtcp2_pktns *pktns; + ngtcp2_duration ack_delay; + uint64_t ack_delay_exponent; + ngtcp2_ssize spktlen; + + assert(!(conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING)); + + switch (type) { + case NGTCP2_PKT_INITIAL: + assert(conn->server); + pktns = conn->in_pktns; + ack_delay = 0; + ack_delay_exponent = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT; + break; + case NGTCP2_PKT_HANDSHAKE: + pktns = conn->hs_pktns; + ack_delay = 0; + ack_delay_exponent = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT; + break; + case NGTCP2_PKT_1RTT: + pktns = &conn->pktns; + ack_delay = conn_compute_ack_delay(conn); + ack_delay_exponent = conn->local.transport_params.ack_delay_exponent; + break; + default: + ngtcp2_unreachable(); + } + + if (!pktns->crypto.tx.ckm) { + return 0; + } + + ackfr = NULL; + rv = conn_create_ack_frame(conn, &ackfr, pktns, type, ts, ack_delay, + ack_delay_exponent); + if (rv != 0) { + return rv; + } + + if (!ackfr) { + return 0; + } + + spktlen = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, type, NGTCP2_WRITE_PKT_FLAG_NONE, + &conn->dcid.current.cid, ackfr, NGTCP2_RTB_ENTRY_FLAG_NONE, NULL, ts); + + if (spktlen <= 0) { + return spktlen; + } + + conn->dcid.current.bytes_sent += (uint64_t)spktlen; + + return spktlen; +} + +static void conn_discard_pktns(ngtcp2_conn *conn, ngtcp2_pktns **ppktns, + ngtcp2_tstamp ts) { + ngtcp2_pktns *pktns = *ppktns; + uint64_t bytes_in_flight; + + bytes_in_flight = pktns->rtb.cc_bytes_in_flight; + + assert(conn->cstat.bytes_in_flight >= bytes_in_flight); + + conn->cstat.bytes_in_flight -= bytes_in_flight; + conn->cstat.pto_count = 0; + conn->cstat.last_tx_pkt_ts[pktns->rtb.pktns_id] = UINT64_MAX; + conn->cstat.loss_time[pktns->rtb.pktns_id] = UINT64_MAX; + + conn_call_delete_crypto_aead_ctx(conn, &pktns->crypto.rx.ckm->aead_ctx); + conn_call_delete_crypto_cipher_ctx(conn, &pktns->crypto.rx.hp_ctx); + conn_call_delete_crypto_aead_ctx(conn, &pktns->crypto.tx.ckm->aead_ctx); + conn_call_delete_crypto_cipher_ctx(conn, &pktns->crypto.tx.hp_ctx); + + pktns_del(pktns, conn->mem); + *ppktns = NULL; + + ngtcp2_conn_set_loss_detection_timer(conn, ts); +} + +/* + * conn_discard_initial_state discards state for Initial packet number + * space. + */ +static void conn_discard_initial_state(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + if (!conn->in_pktns) { + return; + } + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "discarding Initial packet number space"); + + conn_discard_pktns(conn, &conn->in_pktns, ts); + + conn_vneg_crypto_free(conn); + + memset(&conn->vneg.rx, 0, sizeof(conn->vneg.rx)); + memset(&conn->vneg.tx, 0, sizeof(conn->vneg.tx)); +} + +/* + * conn_discard_handshake_state discards state for Handshake packet + * number space. + */ +static void conn_discard_handshake_state(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + if (!conn->hs_pktns) { + return; + } + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "discarding Handshake packet number space"); + + conn_discard_pktns(conn, &conn->hs_pktns, ts); +} + +/* + * conn_discard_early_key discards early key. + */ +static void conn_discard_early_key(ngtcp2_conn *conn) { + assert(conn->early.ckm); + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, "discarding early key"); + + conn_call_delete_crypto_aead_ctx(conn, &conn->early.ckm->aead_ctx); + conn_call_delete_crypto_cipher_ctx(conn, &conn->early.hp_ctx); + memset(&conn->early.hp_ctx, 0, sizeof(conn->early.hp_ctx)); + + ngtcp2_crypto_km_del(conn->early.ckm, conn->mem); + conn->early.ckm = NULL; +} + +/* + * conn_write_handshake_ack_pkts writes packets which contain ACK + * frame only. This function writes at most 2 packets for each + * Initial and Handshake packet. + */ +static ngtcp2_ssize conn_write_handshake_ack_pkts(ngtcp2_conn *conn, + ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + ngtcp2_tstamp ts) { + ngtcp2_ssize res = 0, nwrite = 0; + + /* In the most cases, client sends ACK in conn_write_handshake_pkt. + This function is only called when it is CWND limited or pacing + limited. It is not required for client to send ACK for server + Initial. This is because once it gets server Initial, it gets + Handshake tx key and discards Initial key. The only good reason + to send ACK is give server RTT measurement early. */ + if (conn->server && conn->in_pktns) { + nwrite = + conn_write_ack_pkt(conn, pi, dest, destlen, NGTCP2_PKT_INITIAL, ts); + if (nwrite < 0) { + assert(nwrite != NGTCP2_ERR_NOBUF); + return nwrite; + } + + res += nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + } + + if (conn->hs_pktns->crypto.tx.ckm) { + nwrite = + conn_write_ack_pkt(conn, pi, dest, destlen, NGTCP2_PKT_HANDSHAKE, ts); + if (nwrite < 0) { + assert(nwrite != NGTCP2_ERR_NOBUF); + return nwrite; + } + + res += nwrite; + + if (!conn->server && nwrite) { + conn_discard_initial_state(conn, ts); + } + } + + return res; +} + +/* + * conn_write_client_initial writes Initial packet in the buffer + * pointed by |dest| whose length is |destlen|. + * + * This function returns the number of bytes written in |dest| if it + * succeeds, or one of the following negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static ngtcp2_ssize conn_write_client_initial(ngtcp2_conn *conn, + ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + uint64_t early_datalen, + ngtcp2_tstamp ts) { + int rv; + + rv = conn_call_client_initial(conn); + if (rv != 0) { + return rv; + } + + return conn_write_handshake_pkt(conn, pi, dest, destlen, NGTCP2_PKT_INITIAL, + NGTCP2_WRITE_PKT_FLAG_NONE, early_datalen, + ts); +} + +/* + * dcid_tx_left returns the maximum number of bytes that server is + * allowed to send to an unvalidated path associated to |dcid|. + */ +static uint64_t dcid_tx_left(ngtcp2_dcid *dcid) { + if (dcid->flags & NGTCP2_DCID_FLAG_PATH_VALIDATED) { + return SIZE_MAX; + } + /* From QUIC spec: Prior to validating the client address, servers + MUST NOT send more than three times as many bytes as the number + of bytes they have received. */ + assert(dcid->bytes_recv * 3 >= dcid->bytes_sent); + + return dcid->bytes_recv * 3 - dcid->bytes_sent; +} + +/* + * conn_server_tx_left returns the maximum number of bytes that server + * is allowed to send to an unvalidated path. + */ +static uint64_t conn_server_tx_left(ngtcp2_conn *conn, ngtcp2_dcid *dcid) { + assert(conn->server); + + /* If pv->dcid has the current path, use conn->dcid.current. This + is because conn->dcid.current gets update for bytes_recv and + bytes_sent. */ + if (ngtcp2_path_eq(&dcid->ps.path, &conn->dcid.current.ps.path)) { + return dcid_tx_left(&conn->dcid.current); + } + + return dcid_tx_left(dcid); +} + +/* + * conn_write_handshake_pkts writes Initial and Handshake packets in + * the buffer pointed by |dest| whose length is |destlen|. + * + * This function returns the number of bytes written in |dest| if it + * succeeds, or one of the following negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static ngtcp2_ssize conn_write_handshake_pkts(ngtcp2_conn *conn, + ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + uint64_t write_datalen, + ngtcp2_tstamp ts) { + ngtcp2_ssize nwrite; + ngtcp2_ssize res = 0; + ngtcp2_rtb_entry *rtbent; + uint8_t wflags = NGTCP2_WRITE_PKT_FLAG_NONE; + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_ksl_it it; + + /* As a client, we would like to discard Initial packet number space + when sending the first Handshake packet. When sending Handshake + packet, it should be one of 1) sending ACK, 2) sending PTO probe + packet, or 3) sending CRYPTO. If we have pending acknowledgement + for Initial, then do not discard Initial packet number space. + Otherwise, if either 1) or 2) is satisfied, discard Initial + packet number space. When sending Handshake CRYPTO, it indicates + that client has received Handshake CRYPTO from server. Initial + packet number space is discarded because 1) is met. If there is + pending Initial ACK, Initial packet number space is discarded + after writing the first Handshake packet. + */ + if (!conn->server && conn->hs_pktns->crypto.tx.ckm && conn->in_pktns && + !ngtcp2_acktr_require_active_ack(&conn->in_pktns->acktr, + /* max_ack_delay = */ 0, ts) && + (ngtcp2_acktr_require_active_ack(&conn->hs_pktns->acktr, + /* max_ack_delay = */ 0, ts) || + conn->hs_pktns->rtb.probe_pkt_left)) { + /* Discard Initial state here so that Handshake packet is not + padded. */ + conn_discard_initial_state(conn, ts); + } else if (conn->in_pktns) { + nwrite = + conn_write_handshake_pkt(conn, pi, dest, destlen, NGTCP2_PKT_INITIAL, + NGTCP2_WRITE_PKT_FLAG_NONE, write_datalen, ts); + if (nwrite < 0) { + assert(nwrite != NGTCP2_ERR_NOBUF); + return nwrite; + } + + if (nwrite == 0) { + if (conn->server && (conn->in_pktns->rtb.probe_pkt_left || + ngtcp2_ksl_len(&conn->in_pktns->crypto.tx.frq))) { + if (cstat->loss_detection_timer != UINT64_MAX && + conn_server_tx_left(conn, &conn->dcid.current) < + NGTCP2_MAX_UDP_PAYLOAD_SIZE) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_RCV, + "loss detection timer canceled due to amplification limit"); + cstat->loss_detection_timer = UINT64_MAX; + } + + return 0; + } + } else { + res += nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + + if (destlen) { + /* We might have already added padding to Initial, but in that + case, we should have destlen == 0 and no Handshake packet + will be written. */ + if (conn->server) { + it = ngtcp2_rtb_head(&conn->in_pktns->rtb); + if (!ngtcp2_ksl_it_end(&it)) { + rtbent = ngtcp2_ksl_it_get(&it); + if (rtbent->flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) { + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + } + } else { + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + } + } + } + + nwrite = conn_write_handshake_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_HANDSHAKE, wflags, write_datalen, ts); + if (nwrite < 0) { + assert(nwrite != NGTCP2_ERR_NOBUF); + return nwrite; + } + + res += nwrite; + + if (!conn->server && conn->hs_pktns->crypto.tx.ckm && nwrite) { + /* We don't need to send further Initial packet if we have + Handshake key and sent something with it. So discard initial + state here. */ + conn_discard_initial_state(conn, ts); + } + + return res; +} + +/* + * conn_initial_stream_rx_offset returns the initial maximum offset of + * data for a stream denoted by |stream_id|. + */ +static uint64_t conn_initial_stream_rx_offset(ngtcp2_conn *conn, + int64_t stream_id) { + int local_stream = conn_local_stream(conn, stream_id); + + if (bidi_stream(stream_id)) { + if (local_stream) { + return conn->local.transport_params.initial_max_stream_data_bidi_local; + } + return conn->local.transport_params.initial_max_stream_data_bidi_remote; + } + + if (local_stream) { + return 0; + } + return conn->local.transport_params.initial_max_stream_data_uni; +} + +/* + * conn_should_send_max_stream_data returns nonzero if MAX_STREAM_DATA + * frame should be send for |strm|. + */ +static int conn_should_send_max_stream_data(ngtcp2_conn *conn, + ngtcp2_strm *strm) { + uint64_t inc = strm->rx.unsent_max_offset - strm->rx.max_offset; + (void)conn; + + return strm->rx.window < 2 * inc; +} + +/* + * conn_should_send_max_data returns nonzero if MAX_DATA frame should + * be sent. + */ +static int conn_should_send_max_data(ngtcp2_conn *conn) { + uint64_t inc = conn->rx.unsent_max_offset - conn->rx.max_offset; + + return conn->rx.window < 2 * inc; +} + +/* + * conn_required_num_new_connection_id returns the number of + * additional connection ID the local endpoint has to provide to the + * remote endpoint. + */ +static size_t conn_required_num_new_connection_id(ngtcp2_conn *conn) { + uint64_t n; + size_t len = ngtcp2_ksl_len(&conn->scid.set); + + if (len >= NGTCP2_MAX_SCID_POOL_SIZE) { + return 0; + } + + assert(conn->remote.transport_params); + assert(conn->remote.transport_params->active_connection_id_limit); + + /* len includes retired CID. We don't provide extra CID if doing so + exceeds NGTCP2_MAX_SCID_POOL_SIZE. */ + + n = conn->remote.transport_params->active_connection_id_limit + + conn->scid.num_retired; + + return (size_t)ngtcp2_min(NGTCP2_MAX_SCID_POOL_SIZE, n) - len; +} + +/* + * conn_enqueue_new_connection_id generates additional connection IDs + * and prepares to send them to the remote endpoint. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_enqueue_new_connection_id(ngtcp2_conn *conn) { + size_t i, need = conn_required_num_new_connection_id(conn); + size_t cidlen = conn->oscid.datalen; + ngtcp2_cid cid; + uint64_t seq; + int rv; + uint8_t token[NGTCP2_STATELESS_RESET_TOKENLEN]; + ngtcp2_frame_chain *nfrc; + ngtcp2_pktns *pktns = &conn->pktns; + ngtcp2_scid *scid; + ngtcp2_ksl_it it; + + for (i = 0; i < need; ++i) { + rv = conn_call_get_new_connection_id(conn, &cid, token, cidlen); + if (rv != 0) { + return rv; + } + + if (cid.datalen != cidlen) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + /* Assert uniqueness */ + it = ngtcp2_ksl_lower_bound(&conn->scid.set, &cid); + if (!ngtcp2_ksl_it_end(&it) && + ngtcp2_cid_eq(ngtcp2_ksl_it_key(&it), &cid)) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + seq = ++conn->scid.last_seq; + + scid = ngtcp2_mem_malloc(conn->mem, sizeof(*scid)); + if (scid == NULL) { + return NGTCP2_ERR_NOMEM; + } + + ngtcp2_scid_init(scid, seq, &cid); + + rv = ngtcp2_ksl_insert(&conn->scid.set, NULL, &scid->cid, scid); + if (rv != 0) { + ngtcp2_mem_free(conn->mem, scid); + return rv; + } + + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + nfrc->fr.type = NGTCP2_FRAME_NEW_CONNECTION_ID; + nfrc->fr.new_connection_id.seq = seq; + nfrc->fr.new_connection_id.retire_prior_to = 0; + nfrc->fr.new_connection_id.cid = cid; + memcpy(nfrc->fr.new_connection_id.stateless_reset_token, token, + sizeof(token)); + nfrc->next = pktns->tx.frq; + pktns->tx.frq = nfrc; + } + + return 0; +} + +/* + * conn_remove_retired_connection_id removes the already retired + * connection ID. It waits PTO before actually removing a connection + * ID after it receives RETIRE_CONNECTION_ID from peer to catch + * reordered packets. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_remove_retired_connection_id(ngtcp2_conn *conn, + ngtcp2_duration pto, + ngtcp2_tstamp ts) { + ngtcp2_duration timeout = pto; + ngtcp2_scid *scid; + ngtcp2_dcid *dcid; + int rv; + + for (; !ngtcp2_pq_empty(&conn->scid.used);) { + scid = ngtcp2_struct_of(ngtcp2_pq_top(&conn->scid.used), ngtcp2_scid, pe); + + if (scid->retired_ts == UINT64_MAX || scid->retired_ts + timeout >= ts) { + break; + } + + assert(scid->flags & NGTCP2_SCID_FLAG_RETIRED); + + rv = conn_call_remove_connection_id(conn, &scid->cid); + if (rv != 0) { + return rv; + } + + ngtcp2_ksl_remove(&conn->scid.set, NULL, &scid->cid); + ngtcp2_pq_pop(&conn->scid.used); + ngtcp2_mem_free(conn->mem, scid); + + assert(conn->scid.num_retired); + --conn->scid.num_retired; + } + + for (; ngtcp2_ringbuf_len(&conn->dcid.retired.rb);) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.retired.rb, 0); + if (dcid->retired_ts + timeout >= ts) { + break; + } + + rv = conn_call_deactivate_dcid(conn, dcid); + if (rv != 0) { + return rv; + } + + ngtcp2_ringbuf_pop_front(&conn->dcid.retired.rb); + } + + return 0; +} + +/* + * conn_min_short_pktlen returns the minimum length of Short packet + * this endpoint sends. + */ +static size_t conn_min_short_pktlen(ngtcp2_conn *conn) { + return conn->dcid.current.cid.datalen + NGTCP2_MIN_PKT_EXPANDLEN; +} + +/* + * conn_handle_unconfirmed_key_update_from_remote deals with key + * update which has not been confirmed yet and initiated by the remote + * endpoint. + * + * If key update was initiated by the remote endpoint, acknowledging a + * packet encrypted with the new key completes key update procedure. + */ +static void conn_handle_unconfirmed_key_update_from_remote(ngtcp2_conn *conn, + int64_t largest_ack, + ngtcp2_tstamp ts) { + if (!(conn->flags & NGTCP2_CONN_FLAG_KEY_UPDATE_NOT_CONFIRMED) || + (conn->flags & NGTCP2_CONN_FLAG_KEY_UPDATE_INITIATOR) || + largest_ack < conn->pktns.crypto.rx.ckm->pkt_num) { + return; + } + + conn->flags &= (uint32_t)~NGTCP2_CONN_FLAG_KEY_UPDATE_NOT_CONFIRMED; + conn->crypto.key_update.confirmed_ts = ts; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CRY, "key update confirmed"); +} + +/* + * conn_write_pkt writes a protected packet in the buffer pointed by + * |dest| whose length if |destlen|. |type| specifies the type of + * packet. It can be NGTCP2_PKT_1RTT or NGTCP2_PKT_0RTT. + * + * This function can send new stream data. In order to send stream + * data, specify the underlying stream and parameters to + * |vmsg|->stream. If |vmsg|->stream.fin is set to nonzero, it + * signals that the given data is the final portion of the stream. + * |vmsg|->stream.data vector of length |vmsg|->stream.datacnt + * specifies stream data to send. The number of bytes sent to the + * stream is assigned to *|vmsg|->stream.pdatalen. If 0 length STREAM + * data is sent, 0 is assigned to it. The caller should initialize + * *|vmsg|->stream.pdatalen to -1. + * + * If |require_padding| is nonzero, padding bytes are added to occupy + * the remaining packet payload. + * + * This function returns the number of bytes written in |dest| if it + * succeeds, or one of the following negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_STREAM_DATA_BLOCKED + * Stream data could not be written because of flow control. + */ +static ngtcp2_ssize conn_write_pkt(ngtcp2_conn *conn, ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + ngtcp2_vmsg *vmsg, uint8_t type, + uint8_t flags, ngtcp2_tstamp ts) { + int rv = 0; + ngtcp2_crypto_cc *cc = &conn->pkt.cc; + ngtcp2_ppe *ppe = &conn->pkt.ppe; + ngtcp2_pkt_hd *hd = &conn->pkt.hd; + ngtcp2_frame *ackfr = NULL, lfr; + ngtcp2_ssize nwrite; + ngtcp2_frame_chain **pfrc, *nfrc, *frc; + ngtcp2_rtb_entry *ent; + ngtcp2_strm *strm; + int pkt_empty = 1; + uint64_t ndatalen = 0; + int send_stream = 0; + int stream_blocked = 0; + int send_datagram = 0; + ngtcp2_pktns *pktns = &conn->pktns; + size_t left; + uint64_t datalen = 0; + ngtcp2_vec data[NGTCP2_MAX_STREAM_DATACNT]; + size_t datacnt; + uint16_t rtb_entry_flags = NGTCP2_RTB_ENTRY_FLAG_NONE; + int hd_logged = 0; + ngtcp2_path_challenge_entry *pcent; + uint8_t hd_flags = NGTCP2_PKT_FLAG_NONE; + int require_padding = (flags & NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING) != 0; + int write_more = (flags & NGTCP2_WRITE_PKT_FLAG_MORE) != 0; + int ppe_pending = (conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING) != 0; + size_t min_pktlen = conn_min_short_pktlen(conn); + int padded = 0; + ngtcp2_cc_pkt cc_pkt; + uint64_t crypto_offset; + uint64_t stream_offset; + ngtcp2_ssize num_reclaimed; + int fin; + uint64_t target_max_data; + ngtcp2_conn_stat *cstat = &conn->cstat; + uint64_t delta; + const ngtcp2_cid *scid = NULL; + int keep_alive_expired = 0; + uint32_t version = 0; + + /* Return 0 if destlen is less than minimum packet length which can + trigger Stateless Reset */ + if (destlen < min_pktlen) { + return 0; + } + + if (vmsg) { + switch (vmsg->type) { + case NGTCP2_VMSG_TYPE_STREAM: + datalen = ngtcp2_vec_len(vmsg->stream.data, vmsg->stream.datacnt); + ndatalen = conn_enforce_flow_control(conn, vmsg->stream.strm, datalen); + /* 0 length STREAM frame is allowed */ + if (ndatalen || datalen == 0) { + send_stream = 1; + } else { + stream_blocked = 1; + } + break; + case NGTCP2_VMSG_TYPE_DATAGRAM: + datalen = ngtcp2_vec_len(vmsg->datagram.data, vmsg->datagram.datacnt); + send_datagram = 1; + break; + default: + break; + } + } + + if (!ppe_pending) { + switch (type) { + case NGTCP2_PKT_1RTT: + hd_flags = conn_pkt_flags_short(conn); + scid = NULL; + cc->aead = pktns->crypto.ctx.aead; + cc->hp = pktns->crypto.ctx.hp; + cc->ckm = pktns->crypto.tx.ckm; + cc->hp_ctx = pktns->crypto.tx.hp_ctx; + + assert(conn->negotiated_version); + + version = conn->negotiated_version; + + /* transport parameter is only valid after handshake completion + which means we don't know how many connection ID that remote + peer can accept before handshake completion. */ + if (conn->oscid.datalen && conn_is_handshake_completed(conn)) { + rv = conn_enqueue_new_connection_id(conn); + if (rv != 0) { + return rv; + } + } + + break; + case NGTCP2_PKT_0RTT: + assert(!conn->server); + if (!conn->early.ckm) { + return 0; + } + hd_flags = conn_pkt_flags_long(conn); + scid = &conn->oscid; + cc->aead = conn->early.ctx.aead; + cc->hp = conn->early.ctx.hp; + cc->ckm = conn->early.ckm; + cc->hp_ctx = conn->early.hp_ctx; + version = conn->client_chosen_version; + break; + default: + /* Unreachable */ + ngtcp2_unreachable(); + } + + cc->encrypt = conn->callbacks.encrypt; + cc->hp_mask = conn->callbacks.hp_mask; + + if (conn_should_send_max_data(conn)) { + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + if (conn->local.settings.max_window && + conn->tx.last_max_data_ts != UINT64_MAX && + ts - conn->tx.last_max_data_ts < + NGTCP2_FLOW_WINDOW_RTT_FACTOR * cstat->smoothed_rtt && + conn->local.settings.max_window > conn->rx.window) { + target_max_data = NGTCP2_FLOW_WINDOW_SCALING_FACTOR * conn->rx.window; + if (target_max_data > conn->local.settings.max_window) { + target_max_data = conn->local.settings.max_window; + } + + delta = target_max_data - conn->rx.window; + if (conn->rx.unsent_max_offset + delta > NGTCP2_MAX_VARINT) { + delta = NGTCP2_MAX_VARINT - conn->rx.unsent_max_offset; + } + + conn->rx.window = target_max_data; + } else { + delta = 0; + } + + conn->tx.last_max_data_ts = ts; + + nfrc->fr.type = NGTCP2_FRAME_MAX_DATA; + nfrc->fr.max_data.max_data = conn->rx.unsent_max_offset + delta; + nfrc->next = pktns->tx.frq; + pktns->tx.frq = nfrc; + + conn->rx.max_offset = conn->rx.unsent_max_offset = + nfrc->fr.max_data.max_data; + } + + ngtcp2_pkt_hd_init(hd, hd_flags, type, &conn->dcid.current.cid, scid, + pktns->tx.last_pkt_num + 1, + pktns_select_pkt_numlen(pktns), version, 0); + + ngtcp2_ppe_init(ppe, dest, destlen, cc); + + rv = ngtcp2_ppe_encode_hd(ppe, hd); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return 0; + } + + if (!ngtcp2_ppe_ensure_hp_sample(ppe)) { + return 0; + } + + if (ngtcp2_ringbuf_len(&conn->rx.path_challenge.rb)) { + pcent = ngtcp2_ringbuf_get(&conn->rx.path_challenge.rb, 0); + + /* PATH_RESPONSE is bound to the path that the corresponding + PATH_CHALLENGE is received. */ + if (ngtcp2_path_eq(&conn->dcid.current.ps.path, &pcent->ps.path)) { + lfr.type = NGTCP2_FRAME_PATH_RESPONSE; + memcpy(lfr.path_response.data, pcent->data, + sizeof(lfr.path_response.data)); + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &lfr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + } else { + ngtcp2_ringbuf_pop_front(&conn->rx.path_challenge.rb); + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING; + require_padding = + !conn->server || destlen >= NGTCP2_MAX_UDP_PAYLOAD_SIZE; + /* We don't retransmit PATH_RESPONSE. */ + } + } + } + + rv = conn_create_ack_frame(conn, &ackfr, pktns, type, ts, + conn_compute_ack_delay(conn), + conn->local.transport_params.ack_delay_exponent); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + if (ackfr) { + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, ackfr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + } else { + ngtcp2_acktr_commit_ack(&pktns->acktr); + ngtcp2_acktr_add_ack(&pktns->acktr, hd->pkt_num, + ackfr->ack.largest_ack); + if (type == NGTCP2_PKT_1RTT) { + conn_handle_unconfirmed_key_update_from_remote( + conn, ackfr->ack.largest_ack, ts); + } + pkt_empty = 0; + } + } + + build_pkt: + for (pfrc = &pktns->tx.frq; *pfrc;) { + if ((*pfrc)->binder && + ((*pfrc)->binder->flags & NGTCP2_FRAME_CHAIN_BINDER_FLAG_ACK)) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + + switch ((*pfrc)->fr.type) { + case NGTCP2_FRAME_STOP_SENDING: + strm = + ngtcp2_conn_find_stream(conn, (*pfrc)->fr.stop_sending.stream_id); + if (strm == NULL || (strm->flags & NGTCP2_STRM_FLAG_SHUT_RD)) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + + if (!(strm->flags & NGTCP2_STRM_FLAG_STREAM_STOP_SENDING_CALLED)) { + strm->flags |= NGTCP2_STRM_FLAG_STREAM_STOP_SENDING_CALLED; + + rv = conn_call_stream_stop_sending( + conn, (*pfrc)->fr.stop_sending.stream_id, + (*pfrc)->fr.stop_sending.app_error_code, strm->stream_user_data); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + } + + break; + case NGTCP2_FRAME_STREAM: + ngtcp2_unreachable(); + case NGTCP2_FRAME_MAX_STREAMS_BIDI: + if ((*pfrc)->fr.max_streams.max_streams < + conn->remote.bidi.max_streams) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + break; + case NGTCP2_FRAME_MAX_STREAMS_UNI: + if ((*pfrc)->fr.max_streams.max_streams < + conn->remote.uni.max_streams) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + break; + case NGTCP2_FRAME_MAX_STREAM_DATA: + strm = ngtcp2_conn_find_stream(conn, + (*pfrc)->fr.max_stream_data.stream_id); + if (strm == NULL || (strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) || + (*pfrc)->fr.max_stream_data.max_stream_data < strm->rx.max_offset) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + break; + case NGTCP2_FRAME_MAX_DATA: + if ((*pfrc)->fr.max_data.max_data < conn->rx.max_offset) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + continue; + } + break; + case NGTCP2_FRAME_CRYPTO: + ngtcp2_unreachable(); + } + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &(*pfrc)->fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + break; + } + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + pfrc = &(*pfrc)->next; + } + + if (rv != NGTCP2_ERR_NOBUF) { + for (; ngtcp2_ksl_len(&pktns->crypto.tx.frq);) { + left = ngtcp2_ppe_left(ppe); + + crypto_offset = conn_cryptofrq_unacked_offset(conn, pktns); + if (crypto_offset == (size_t)-1) { + conn_cryptofrq_clear(conn, pktns); + break; + } + + left = ngtcp2_pkt_crypto_max_datalen(crypto_offset, left, left); + + if (left == (size_t)-1) { + break; + } + + rv = conn_cryptofrq_pop(conn, &nfrc, pktns, left); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + if (nfrc == NULL) { + break; + } + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &nfrc->fr); + if (rv != 0) { + ngtcp2_unreachable(); + } + + *pfrc = nfrc; + pfrc = &(*pfrc)->next; + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + } + } + + /* Write MAX_STREAM_ID after RESET_STREAM so that we can extend stream + ID space in one packet. */ + if (rv != NGTCP2_ERR_NOBUF && *pfrc == NULL && + conn->remote.bidi.unsent_max_streams > conn->remote.bidi.max_streams) { + rv = conn_call_extend_max_remote_streams_bidi( + conn, conn->remote.bidi.unsent_max_streams); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + nfrc->fr.type = NGTCP2_FRAME_MAX_STREAMS_BIDI; + nfrc->fr.max_streams.max_streams = conn->remote.bidi.unsent_max_streams; + *pfrc = nfrc; + + conn->remote.bidi.max_streams = conn->remote.bidi.unsent_max_streams; + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &(*pfrc)->fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + } else { + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + pfrc = &(*pfrc)->next; + } + } + + if (rv != NGTCP2_ERR_NOBUF && *pfrc == NULL) { + if (conn->remote.uni.unsent_max_streams > conn->remote.uni.max_streams) { + rv = conn_call_extend_max_remote_streams_uni( + conn, conn->remote.uni.unsent_max_streams); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + nfrc->fr.type = NGTCP2_FRAME_MAX_STREAMS_UNI; + nfrc->fr.max_streams.max_streams = conn->remote.uni.unsent_max_streams; + *pfrc = nfrc; + + conn->remote.uni.max_streams = conn->remote.uni.unsent_max_streams; + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, + &(*pfrc)->fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + } else { + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + pfrc = &(*pfrc)->next; + } + } + } + + if (rv != NGTCP2_ERR_NOBUF) { + for (; !ngtcp2_pq_empty(&conn->tx.strmq);) { + strm = ngtcp2_conn_tx_strmq_top(conn); + + if (!(strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) && + conn_should_send_max_stream_data(conn, strm)) { + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + if (conn->local.settings.max_stream_window && + strm->tx.last_max_stream_data_ts != UINT64_MAX && + ts - strm->tx.last_max_stream_data_ts < + NGTCP2_FLOW_WINDOW_RTT_FACTOR * cstat->smoothed_rtt && + conn->local.settings.max_stream_window > strm->rx.window) { + target_max_data = + NGTCP2_FLOW_WINDOW_SCALING_FACTOR * strm->rx.window; + if (target_max_data > conn->local.settings.max_stream_window) { + target_max_data = conn->local.settings.max_stream_window; + } + + delta = target_max_data - strm->rx.window; + if (strm->rx.unsent_max_offset + delta > NGTCP2_MAX_VARINT) { + delta = NGTCP2_MAX_VARINT - strm->rx.unsent_max_offset; + } + + strm->rx.window = target_max_data; + } else { + delta = 0; + } + + strm->tx.last_max_stream_data_ts = ts; + + nfrc->fr.type = NGTCP2_FRAME_MAX_STREAM_DATA; + nfrc->fr.max_stream_data.stream_id = strm->stream_id; + nfrc->fr.max_stream_data.max_stream_data = + strm->rx.unsent_max_offset + delta; + ngtcp2_list_insert(nfrc, pfrc); + + rv = + conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &nfrc->fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + break; + } + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + pfrc = &(*pfrc)->next; + strm->rx.max_offset = strm->rx.unsent_max_offset = + nfrc->fr.max_stream_data.max_stream_data; + } + + if (ngtcp2_strm_streamfrq_empty(strm)) { + ngtcp2_conn_tx_strmq_pop(conn); + continue; + } + + stream_offset = ngtcp2_strm_streamfrq_unacked_offset(strm); + if (stream_offset == (uint64_t)-1) { + ngtcp2_strm_streamfrq_clear(strm); + ngtcp2_conn_tx_strmq_pop(conn); + assert(conn->tx.strmq_nretrans); + --conn->tx.strmq_nretrans; + continue; + } + + left = ngtcp2_ppe_left(ppe); + + left = ngtcp2_pkt_stream_max_datalen(strm->stream_id, stream_offset, + left, left); + + if (left == (size_t)-1) { + break; + } + + rv = ngtcp2_strm_streamfrq_pop(strm, &nfrc, left); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + if (nfrc == NULL) { + /* TODO Why? */ + break; + } + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &nfrc->fr); + if (rv != 0) { + ngtcp2_unreachable(); + } + + *pfrc = nfrc; + pfrc = &(*pfrc)->next; + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + + if (ngtcp2_strm_streamfrq_empty(strm)) { + ngtcp2_conn_tx_strmq_pop(conn); + assert(conn->tx.strmq_nretrans); + --conn->tx.strmq_nretrans; + continue; + } + + ngtcp2_conn_tx_strmq_pop(conn); + ++strm->cycle; + rv = ngtcp2_conn_tx_strmq_push(conn, strm); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + } + } + + if (rv != NGTCP2_ERR_NOBUF && !send_stream && !send_datagram && + !(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) && + pktns->rtb.num_retransmittable && pktns->tx.frq == NULL && + pktns->rtb.probe_pkt_left) { + num_reclaimed = ngtcp2_rtb_reclaim_on_pto(&pktns->rtb, conn, pktns, 1); + if (num_reclaimed < 0) { + return rv; + } + if (num_reclaimed) { + goto build_pkt; + } + + /* We had pktns->rtb.num_retransmittable > 0 but we were unable + to reclaim any frame. In this case, we do not have to send + any probe packet. */ + if (pktns->rtb.num_pto_eliciting == 0) { + pktns->rtb.probe_pkt_left = 0; + ngtcp2_conn_set_loss_detection_timer(conn, ts); + + if (pkt_empty && conn_cwnd_is_zero(conn) && !require_padding) { + return 0; + } + } + } + } else { + pfrc = conn->pkt.pfrc; + rtb_entry_flags |= conn->pkt.rtb_entry_flags; + pkt_empty = conn->pkt.pkt_empty; + hd_logged = conn->pkt.hd_logged; + } + + left = ngtcp2_ppe_left(ppe); + + if (rv != NGTCP2_ERR_NOBUF && send_stream && *pfrc == NULL && + (ndatalen = ngtcp2_pkt_stream_max_datalen( + vmsg->stream.strm->stream_id, vmsg->stream.strm->tx.offset, ndatalen, + left)) != (size_t)-1 && + (ndatalen || datalen == 0)) { + datacnt = ngtcp2_vec_copy_at_most(data, NGTCP2_MAX_STREAM_DATACNT, + vmsg->stream.data, vmsg->stream.datacnt, + (size_t)ndatalen); + ndatalen = ngtcp2_vec_len(data, datacnt); + + assert((datacnt == 0 && datalen == 0) || (datacnt && datalen)); + + rv = ngtcp2_frame_chain_stream_datacnt_objalloc_new( + &nfrc, datacnt, &conn->frc_objalloc, conn->mem); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + nfrc->fr.stream.type = NGTCP2_FRAME_STREAM; + nfrc->fr.stream.flags = 0; + nfrc->fr.stream.stream_id = vmsg->stream.strm->stream_id; + nfrc->fr.stream.offset = vmsg->stream.strm->tx.offset; + nfrc->fr.stream.datacnt = datacnt; + ngtcp2_vec_copy(nfrc->fr.stream.data, data, datacnt); + + fin = (vmsg->stream.flags & NGTCP2_WRITE_STREAM_FLAG_FIN) && + ndatalen == datalen; + nfrc->fr.stream.fin = (uint8_t)fin; + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &nfrc->fr); + if (rv != 0) { + ngtcp2_unreachable(); + } + + *pfrc = nfrc; + pfrc = &(*pfrc)->next; + + pkt_empty = 0; + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_RETRANSMITTABLE; + + vmsg->stream.strm->tx.offset += ndatalen; + conn->tx.offset += ndatalen; + + if (fin) { + ngtcp2_strm_shutdown(vmsg->stream.strm, NGTCP2_STRM_FLAG_SHUT_WR); + } + + if (vmsg->stream.pdatalen) { + *vmsg->stream.pdatalen = (ngtcp2_ssize)ndatalen; + } + } else { + send_stream = 0; + } + + if (rv != NGTCP2_ERR_NOBUF && send_datagram && + left >= ngtcp2_pkt_datagram_framelen((size_t)datalen)) { + if (conn->callbacks.ack_datagram || conn->callbacks.lost_datagram) { + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + nfrc->fr.datagram.type = NGTCP2_FRAME_DATAGRAM_LEN; + nfrc->fr.datagram.dgram_id = vmsg->datagram.dgram_id; + nfrc->fr.datagram.datacnt = vmsg->datagram.datacnt; + nfrc->fr.datagram.data = (ngtcp2_vec *)vmsg->datagram.data; + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &nfrc->fr); + assert(rv == 0); + + /* Because DATAGRAM will not be retransmitted, we do not use + data anymore. Just nullify it. The only reason to keep + track a frame is keep dgram_id to pass it to + ngtcp2_ack_datagram or ngtcp2_lost_datagram callbacks. */ + nfrc->fr.datagram.datacnt = 0; + nfrc->fr.datagram.data = NULL; + + *pfrc = nfrc; + pfrc = &(*pfrc)->next; + } else { + lfr.datagram.type = NGTCP2_FRAME_DATAGRAM_LEN; + lfr.datagram.datacnt = vmsg->datagram.datacnt; + lfr.datagram.data = (ngtcp2_vec *)vmsg->datagram.data; + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &lfr); + assert(rv == 0); + } + + pkt_empty = 0; + rtb_entry_flags |= + NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | NGTCP2_RTB_ENTRY_FLAG_DATAGRAM; + + if (vmsg->datagram.paccepted) { + *vmsg->datagram.paccepted = 1; + } + } else { + send_datagram = 0; + } + + if (pkt_empty) { + assert(rv == 0 || NGTCP2_ERR_NOBUF == rv); + if (rv == 0 && stream_blocked && ngtcp2_conn_get_max_data_left(conn)) { + return NGTCP2_ERR_STREAM_DATA_BLOCKED; + } + + keep_alive_expired = conn_keep_alive_expired(conn, ts); + + if (conn->pktns.rtb.probe_pkt_left == 0 && !keep_alive_expired && + !require_padding) { + return 0; + } + } else if (write_more) { + conn->pkt.pfrc = pfrc; + conn->pkt.pkt_empty = pkt_empty; + conn->pkt.rtb_entry_flags = rtb_entry_flags; + conn->pkt.hd_logged = hd_logged; + conn->flags |= NGTCP2_CONN_FLAG_PPE_PENDING; + + assert(vmsg); + + switch (vmsg->type) { + case NGTCP2_VMSG_TYPE_STREAM: + if (send_stream) { + if (ngtcp2_ppe_left(ppe)) { + return NGTCP2_ERR_WRITE_MORE; + } + break; + } + + if (ngtcp2_conn_get_max_data_left(conn) && stream_blocked) { + return NGTCP2_ERR_STREAM_DATA_BLOCKED; + } + break; + case NGTCP2_VMSG_TYPE_DATAGRAM: + if (send_datagram && ngtcp2_ppe_left(ppe)) { + return NGTCP2_ERR_WRITE_MORE; + } + /* If DATAGRAM cannot be written due to insufficient space, + continue to create a packet with the hope that application + calls ngtcp2_conn_writev_datagram again. */ + break; + default: + ngtcp2_unreachable(); + } + } + + if (!(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING)) { + if (pktns->tx.num_non_ack_pkt >= NGTCP2_MAX_NON_ACK_TX_PKT || + keep_alive_expired || conn->pktns.rtb.probe_pkt_left) { + lfr.type = NGTCP2_FRAME_PING; + + rv = conn_ppe_write_frame_hd_log(conn, ppe, &hd_logged, hd, &lfr); + if (rv != 0) { + assert(rv == NGTCP2_ERR_NOBUF); + /* TODO If buffer is too small, PING cannot be written if + packet is still empty. */ + } else { + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING; + if (conn->pktns.rtb.probe_pkt_left) { + rtb_entry_flags |= NGTCP2_RTB_ENTRY_FLAG_PROBE; + } + pktns->tx.num_non_ack_pkt = 0; + } + } else { + ++pktns->tx.num_non_ack_pkt; + } + } else { + pktns->tx.num_non_ack_pkt = 0; + } + + /* TODO Push STREAM frame back to ngtcp2_strm if there is an error + before ngtcp2_rtb_entry is safely created and added. */ + if (require_padding || + /* Making full sized packet will help GSO a bit */ + ngtcp2_ppe_left(ppe) < 10) { + lfr.padding.len = ngtcp2_ppe_padding(ppe); + } else { + lfr.padding.len = ngtcp2_ppe_padding_size(ppe, min_pktlen); + } + + if (lfr.padding.len) { + lfr.type = NGTCP2_FRAME_PADDING; + padded = 1; + ngtcp2_log_tx_fr(&conn->log, hd, &lfr); + ngtcp2_qlog_write_frame(&conn->qlog, &lfr); + } + + nwrite = ngtcp2_ppe_final(ppe, NULL); + if (nwrite < 0) { + assert(ngtcp2_err_is_fatal((int)nwrite)); + return nwrite; + } + + ++cc->ckm->use_count; + + ngtcp2_qlog_pkt_sent_end(&conn->qlog, hd, (size_t)nwrite); + + /* TODO ack-eliciting vs needs-tracking */ + /* probe packet needs tracking but it does not need ACK, could be lost. */ + if ((rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) || padded) { + if (pi) { + conn_handle_tx_ecn(conn, pi, &rtb_entry_flags, pktns, hd, ts); + } + + rv = ngtcp2_rtb_entry_objalloc_new(&ent, hd, NULL, ts, (size_t)nwrite, + rtb_entry_flags, + &conn->rtb_entry_objalloc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal((int)nwrite)); + return rv; + } + + if (*pfrc != pktns->tx.frq) { + ent->frc = pktns->tx.frq; + pktns->tx.frq = *pfrc; + *pfrc = NULL; + } + + if ((rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) && + pktns->rtb.num_ack_eliciting == 0 && conn->cc.event) { + conn->cc.event(&conn->cc, &conn->cstat, NGTCP2_CC_EVENT_TYPE_TX_START, + ts); + } + + rv = conn_on_pkt_sent(conn, &pktns->rtb, ent); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_rtb_entry_objalloc_del(ent, &conn->rtb_entry_objalloc, + &conn->frc_objalloc, conn->mem); + return rv; + } + + if (rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) { + if (conn->cc.on_pkt_sent) { + conn->cc.on_pkt_sent( + &conn->cc, &conn->cstat, + ngtcp2_cc_pkt_init(&cc_pkt, hd->pkt_num, (size_t)nwrite, + NGTCP2_PKTNS_ID_APPLICATION, ts, ent->rst.lost, + ent->rst.tx_in_flight, ent->rst.is_app_limited)); + } + + if (conn->flags & NGTCP2_CONN_FLAG_RESTART_IDLE_TIMER_ON_WRITE) { + conn_restart_timer_on_write(conn, ts); + } + } + } else if (pi && conn->tx.ecn.state == NGTCP2_ECN_STATE_CAPABLE) { + conn_handle_tx_ecn(conn, pi, NULL, pktns, hd, ts); + } + + conn->flags &= (uint32_t)~NGTCP2_CONN_FLAG_PPE_PENDING; + + if (pktns->rtb.probe_pkt_left && + (rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING)) { + --pktns->rtb.probe_pkt_left; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, "probe pkt size=%td", + nwrite); + } + + conn_update_keep_alive_last_ts(conn, ts); + + conn->dcid.current.bytes_sent += (uint64_t)nwrite; + + conn->tx.pacing.pktlen += (size_t)nwrite; + + ngtcp2_qlog_metrics_updated(&conn->qlog, &conn->cstat); + + ++pktns->tx.last_pkt_num; + + return nwrite; +} + +ngtcp2_ssize ngtcp2_conn_write_single_frame_pkt( + ngtcp2_conn *conn, ngtcp2_pkt_info *pi, uint8_t *dest, size_t destlen, + uint8_t type, uint8_t flags, const ngtcp2_cid *dcid, ngtcp2_frame *fr, + uint16_t rtb_entry_flags, const ngtcp2_path *path, ngtcp2_tstamp ts) { + int rv; + ngtcp2_ppe ppe; + ngtcp2_pkt_hd hd; + ngtcp2_frame lfr; + ngtcp2_ssize nwrite; + ngtcp2_crypto_cc cc; + ngtcp2_pktns *pktns; + uint8_t hd_flags; + ngtcp2_rtb_entry *rtbent; + int padded = 0; + const ngtcp2_cid *scid; + uint32_t version; + + switch (type) { + case NGTCP2_PKT_INITIAL: + pktns = conn->in_pktns; + hd_flags = conn_pkt_flags_long(conn); + scid = &conn->oscid; + version = conn->negotiated_version ? conn->negotiated_version + : conn->client_chosen_version; + if (version == conn->client_chosen_version) { + cc.ckm = pktns->crypto.tx.ckm; + cc.hp_ctx = pktns->crypto.tx.hp_ctx; + } else { + assert(version == conn->vneg.version); + + cc.ckm = conn->vneg.tx.ckm; + cc.hp_ctx = conn->vneg.tx.hp_ctx; + } + break; + case NGTCP2_PKT_HANDSHAKE: + pktns = conn->hs_pktns; + hd_flags = conn_pkt_flags_long(conn); + scid = &conn->oscid; + version = conn->negotiated_version; + cc.ckm = pktns->crypto.tx.ckm; + cc.hp_ctx = pktns->crypto.tx.hp_ctx; + break; + case NGTCP2_PKT_1RTT: + pktns = &conn->pktns; + hd_flags = conn_pkt_flags_short(conn); + scid = NULL; + version = conn->negotiated_version; + cc.ckm = pktns->crypto.tx.ckm; + cc.hp_ctx = pktns->crypto.tx.hp_ctx; + break; + default: + /* We don't support 0-RTT packet in this function. */ + ngtcp2_unreachable(); + } + + cc.aead = pktns->crypto.ctx.aead; + cc.hp = pktns->crypto.ctx.hp; + cc.encrypt = conn->callbacks.encrypt; + cc.hp_mask = conn->callbacks.hp_mask; + + ngtcp2_pkt_hd_init(&hd, hd_flags, type, dcid, scid, + pktns->tx.last_pkt_num + 1, pktns_select_pkt_numlen(pktns), + version, 0); + + ngtcp2_ppe_init(&ppe, dest, destlen, &cc); + + rv = ngtcp2_ppe_encode_hd(&ppe, &hd); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return 0; + } + + if (!ngtcp2_ppe_ensure_hp_sample(&ppe)) { + return 0; + } + + ngtcp2_log_tx_pkt_hd(&conn->log, &hd); + ngtcp2_qlog_pkt_sent_start(&conn->qlog); + + rv = conn_ppe_write_frame(conn, &ppe, &hd, fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return 0; + } + + lfr.type = NGTCP2_FRAME_PADDING; + if (flags & NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING) { + lfr.padding.len = ngtcp2_ppe_padding(&ppe); + } else { + switch (fr->type) { + case NGTCP2_FRAME_PATH_CHALLENGE: + case NGTCP2_FRAME_PATH_RESPONSE: + if (!conn->server || destlen >= NGTCP2_MAX_UDP_PAYLOAD_SIZE) { + lfr.padding.len = ngtcp2_ppe_padding(&ppe); + } else { + lfr.padding.len = 0; + } + break; + default: + if (type == NGTCP2_PKT_1RTT) { + lfr.padding.len = + ngtcp2_ppe_padding_size(&ppe, conn_min_short_pktlen(conn)); + } else { + lfr.padding.len = ngtcp2_ppe_padding_hp_sample(&ppe); + } + } + } + if (lfr.padding.len) { + padded = 1; + ngtcp2_log_tx_fr(&conn->log, &hd, &lfr); + ngtcp2_qlog_write_frame(&conn->qlog, &lfr); + } + + nwrite = ngtcp2_ppe_final(&ppe, NULL); + if (nwrite < 0) { + return nwrite; + } + + if (type == NGTCP2_PKT_1RTT) { + ++cc.ckm->use_count; + } + + ngtcp2_qlog_pkt_sent_end(&conn->qlog, &hd, (size_t)nwrite); + + /* Do this when we are sure that there is no error. */ + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + ngtcp2_acktr_commit_ack(&pktns->acktr); + ngtcp2_acktr_add_ack(&pktns->acktr, hd.pkt_num, fr->ack.largest_ack); + if (type == NGTCP2_PKT_1RTT) { + conn_handle_unconfirmed_key_update_from_remote(conn, fr->ack.largest_ack, + ts); + } + break; + } + + if (((rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) || padded) && + (!path || ngtcp2_path_eq(&conn->dcid.current.ps.path, path))) { + if (pi && !(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_PMTUD_PROBE)) { + conn_handle_tx_ecn(conn, pi, &rtb_entry_flags, pktns, &hd, ts); + } + + rv = ngtcp2_rtb_entry_objalloc_new(&rtbent, &hd, NULL, ts, (size_t)nwrite, + rtb_entry_flags, + &conn->rtb_entry_objalloc); + if (rv != 0) { + return rv; + } + + rv = conn_on_pkt_sent(conn, &pktns->rtb, rtbent); + if (rv != 0) { + ngtcp2_rtb_entry_objalloc_del(rtbent, &conn->rtb_entry_objalloc, + &conn->frc_objalloc, conn->mem); + return rv; + } + + if (rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING) { + if (conn->flags & NGTCP2_CONN_FLAG_RESTART_IDLE_TIMER_ON_WRITE) { + conn_restart_timer_on_write(conn, ts); + } + + if (pktns->rtb.probe_pkt_left && path && + ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + --pktns->rtb.probe_pkt_left; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, "probe pkt size=%td", + nwrite); + } + } + } else if (pi && !(rtb_entry_flags & NGTCP2_RTB_ENTRY_FLAG_PMTUD_PROBE) && + conn->tx.ecn.state == NGTCP2_ECN_STATE_CAPABLE) { + conn_handle_tx_ecn(conn, pi, NULL, pktns, &hd, ts); + } + + if (path && ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + conn_update_keep_alive_last_ts(conn, ts); + } + + if (!padded) { + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + break; + default: + conn->tx.pacing.pktlen += (size_t)nwrite; + } + } else { + conn->tx.pacing.pktlen += (size_t)nwrite; + } + + ngtcp2_qlog_metrics_updated(&conn->qlog, &conn->cstat); + + ++pktns->tx.last_pkt_num; + + return nwrite; +} + +/* + * conn_process_early_rtb makes any pending 0RTT packet 1RTT packet. + */ +static void conn_process_early_rtb(ngtcp2_conn *conn) { + ngtcp2_rtb_entry *ent; + ngtcp2_rtb *rtb = &conn->pktns.rtb; + ngtcp2_ksl_it it; + + for (it = ngtcp2_rtb_head(rtb); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + ent = ngtcp2_ksl_it_get(&it); + + if ((ent->hd.flags & NGTCP2_PKT_FLAG_LONG_FORM) == 0 || + ent->hd.type != NGTCP2_PKT_0RTT) { + continue; + } + + /* 0-RTT packet is retransmitted as a 1RTT packet. */ + ent->hd.flags &= (uint8_t)~NGTCP2_PKT_FLAG_LONG_FORM; + ent->hd.type = NGTCP2_PKT_1RTT; + } +} + +/* + * conn_handshake_remnants_left returns nonzero if there may be + * handshake packets the local endpoint has to send, including new + * packets and lost ones. + */ +static int conn_handshake_remnants_left(ngtcp2_conn *conn) { + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + + return !conn_is_handshake_completed(conn) || + (in_pktns && (in_pktns->rtb.num_pto_eliciting || + ngtcp2_ksl_len(&in_pktns->crypto.tx.frq))) || + (hs_pktns && (hs_pktns->rtb.num_pto_eliciting || + ngtcp2_ksl_len(&hs_pktns->crypto.tx.frq))); +} + +/* + * conn_retire_dcid_seq retires destination connection ID denoted by + * |seq|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CONNECTION_ID_LIMIT + * The number of unacknowledged retirement exceeds the limit. + */ +static int conn_retire_dcid_seq(ngtcp2_conn *conn, uint64_t seq) { + ngtcp2_pktns *pktns = &conn->pktns; + ngtcp2_frame_chain *nfrc; + int rv; + + rv = ngtcp2_conn_track_retired_dcid_seq(conn, seq); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + nfrc->fr.type = NGTCP2_FRAME_RETIRE_CONNECTION_ID; + nfrc->fr.retire_connection_id.seq = seq; + nfrc->next = pktns->tx.frq; + pktns->tx.frq = nfrc; + + return 0; +} + +/* + * conn_retire_dcid retires |dcid|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + */ +static int conn_retire_dcid(ngtcp2_conn *conn, const ngtcp2_dcid *dcid, + ngtcp2_tstamp ts) { + ngtcp2_ringbuf *rb = &conn->dcid.retired.rb; + ngtcp2_dcid *dest, *stale_dcid; + int rv; + + assert(dcid->cid.datalen); + + if (ngtcp2_ringbuf_full(rb)) { + stale_dcid = ngtcp2_ringbuf_get(rb, 0); + rv = conn_call_deactivate_dcid(conn, stale_dcid); + if (rv != 0) { + return rv; + } + + ngtcp2_ringbuf_pop_front(rb); + } + + dest = ngtcp2_ringbuf_push_back(rb); + ngtcp2_dcid_copy(dest, dcid); + dest->retired_ts = ts; + + return conn_retire_dcid_seq(conn, dcid->seq); +} + +/* + * conn_bind_dcid stores the DCID to |*pdcid| bound to |path|. If + * such DCID is not found, bind the new DCID to |path| and stores it + * to |*pdcid|. If a remote endpoint uses zero-length connection ID, + * the pointer to conn->dcid.current is assigned to |*pdcid|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CONN_ID_BLOCKED + * No unused DCID is available + * NGTCP2_ERR_NOMEM + * Out of memory + */ +static int conn_bind_dcid(ngtcp2_conn *conn, ngtcp2_dcid **pdcid, + const ngtcp2_path *path, ngtcp2_tstamp ts) { + ngtcp2_dcid *dcid, *ndcid; + ngtcp2_cid cid; + size_t i, len; + int rv; + + assert(!ngtcp2_path_eq(&conn->dcid.current.ps.path, path)); + assert(!conn->pv || !ngtcp2_path_eq(&conn->pv->dcid.ps.path, path)); + assert(!conn->pv || !(conn->pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) || + !ngtcp2_path_eq(&conn->pv->fallback_dcid.ps.path, path)); + + len = ngtcp2_ringbuf_len(&conn->dcid.bound.rb); + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, i); + + if (ngtcp2_path_eq(&dcid->ps.path, path)) { + *pdcid = dcid; + return 0; + } + } + + if (conn->dcid.current.cid.datalen == 0) { + ndcid = ngtcp2_ringbuf_push_back(&conn->dcid.bound.rb); + ngtcp2_cid_zero(&cid); + ngtcp2_dcid_init(ndcid, ++conn->dcid.zerolen_seq, &cid, NULL); + ngtcp2_dcid_set_path(ndcid, path); + + *pdcid = ndcid; + + return 0; + } + + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb) == 0) { + return NGTCP2_ERR_CONN_ID_BLOCKED; + } + + if (ngtcp2_ringbuf_full(&conn->dcid.bound.rb)) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, 0); + rv = conn_retire_dcid(conn, dcid, ts); + if (rv != 0) { + return rv; + } + } + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + ndcid = ngtcp2_ringbuf_push_back(&conn->dcid.bound.rb); + + ngtcp2_dcid_copy(ndcid, dcid); + ndcid->bound_ts = ts; + ngtcp2_dcid_set_path(ndcid, path); + + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + + *pdcid = ndcid; + + return 0; +} + +static int conn_start_pmtud(ngtcp2_conn *conn) { + int rv; + size_t hard_max_udp_payload_size; + + assert(!conn->local.settings.no_pmtud); + assert(!conn->pmtud); + assert(conn_is_handshake_completed(conn)); + assert(conn->remote.transport_params); + assert(conn->remote.transport_params->max_udp_payload_size >= + NGTCP2_MAX_UDP_PAYLOAD_SIZE); + + hard_max_udp_payload_size = (size_t)ngtcp2_min( + conn->remote.transport_params->max_udp_payload_size, + (uint64_t)conn->local.settings.max_tx_udp_payload_size); + + rv = ngtcp2_pmtud_new(&conn->pmtud, conn->dcid.current.max_udp_payload_size, + hard_max_udp_payload_size, + conn->pktns.tx.last_pkt_num + 1, conn->mem); + if (rv != 0) { + return rv; + } + + if (ngtcp2_pmtud_finished(conn->pmtud)) { + ngtcp2_conn_stop_pmtud(conn); + } + + return 0; +} + +int ngtcp2_conn_start_pmtud(ngtcp2_conn *conn) { + return conn_start_pmtud(conn); +} + +void ngtcp2_conn_stop_pmtud(ngtcp2_conn *conn) { + if (!conn->pmtud) { + return; + } + + ngtcp2_pmtud_del(conn->pmtud); + + conn->pmtud = NULL; +} + +static ngtcp2_ssize conn_write_pmtud_probe(ngtcp2_conn *conn, + ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, ngtcp2_tstamp ts) { + size_t probelen; + ngtcp2_ssize nwrite; + ngtcp2_frame lfr; + + assert(conn->pmtud); + assert(!ngtcp2_pmtud_finished(conn->pmtud)); + + if (!ngtcp2_pmtud_require_probe(conn->pmtud)) { + return 0; + } + + probelen = ngtcp2_pmtud_probelen(conn->pmtud); + if (probelen > destlen) { + return 0; + } + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "sending PMTUD probe packet len=%zu", probelen); + + lfr.type = NGTCP2_FRAME_PING; + + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, probelen, NGTCP2_PKT_1RTT, + NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING, &conn->dcid.current.cid, &lfr, + NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING | + NGTCP2_RTB_ENTRY_FLAG_PMTUD_PROBE, + NULL, ts); + if (nwrite < 0) { + return nwrite; + } + + assert(nwrite); + + ngtcp2_pmtud_probe_sent(conn->pmtud, conn_compute_pto(conn, &conn->pktns), + ts); + + return nwrite; +} + +/* + * conn_stop_pv stops the path validation which is currently running. + * This function does nothing if no path validation is currently being + * performed. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + */ +static int conn_stop_pv(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + int rv = 0; + ngtcp2_pv *pv = conn->pv; + + if (pv == NULL) { + return 0; + } + + if (pv->dcid.cid.datalen && pv->dcid.seq != conn->dcid.current.seq) { + rv = conn_retire_dcid(conn, &pv->dcid, ts); + if (rv != 0) { + goto fin; + } + } + + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + pv->fallback_dcid.cid.datalen && + pv->fallback_dcid.seq != conn->dcid.current.seq && + pv->fallback_dcid.seq != pv->dcid.seq) { + rv = conn_retire_dcid(conn, &pv->fallback_dcid, ts); + if (rv != 0) { + goto fin; + } + } + +fin: + ngtcp2_pv_del(pv); + conn->pv = NULL; + + return rv; +} + +/* + * conn_abort_pv aborts the current path validation and frees + * resources allocated for it. This function assumes that conn->pv is + * not NULL. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_abort_pv(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + ngtcp2_pv *pv = conn->pv; + int rv; + + assert(pv); + + if (!(pv->flags & NGTCP2_PV_FLAG_DONT_CARE)) { + rv = conn_call_path_validation(conn, pv, + NGTCP2_PATH_VALIDATION_RESULT_ABORTED); + if (rv != 0) { + return rv; + } + } + + return conn_stop_pv(conn, ts); +} + +static size_t conn_shape_udp_payload(ngtcp2_conn *conn, const ngtcp2_dcid *dcid, + size_t payloadlen) { + if (conn->remote.transport_params && + conn->remote.transport_params->max_udp_payload_size) { + assert(conn->remote.transport_params->max_udp_payload_size >= + NGTCP2_MAX_UDP_PAYLOAD_SIZE); + + payloadlen = + (size_t)ngtcp2_min((uint64_t)payloadlen, + conn->remote.transport_params->max_udp_payload_size); + } + + payloadlen = + ngtcp2_min(payloadlen, conn->local.settings.max_tx_udp_payload_size); + + if (conn->local.settings.no_tx_udp_payload_size_shaping) { + return payloadlen; + } + + return ngtcp2_min(payloadlen, dcid->max_udp_payload_size); +} + +static void conn_reset_congestion_state(ngtcp2_conn *conn, ngtcp2_tstamp ts); + +/* + * conn_on_path_validation_failed is called when path validation + * fails. This function may delete |pv|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_on_path_validation_failed(ngtcp2_conn *conn, ngtcp2_pv *pv, + ngtcp2_tstamp ts) { + int rv; + + if (!(pv->flags & NGTCP2_PV_FLAG_DONT_CARE)) { + rv = conn_call_path_validation(conn, pv, + NGTCP2_PATH_VALIDATION_RESULT_FAILURE); + if (rv != 0) { + return rv; + } + } + + if (pv->flags & NGTCP2_PV_FLAG_MTU_PROBE) { + return NGTCP2_ERR_NO_VIABLE_PATH; + } + + if (pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) { + ngtcp2_dcid_copy(&conn->dcid.current, &pv->fallback_dcid); + conn_reset_congestion_state(conn, ts); + } + + return conn_stop_pv(conn, ts); +} + +/* + * conn_write_path_challenge writes a packet which includes + * PATH_CHALLENGE frame into |dest| of length |destlen|. + * + * This function returns the number of bytes written to |dest|, or one + * of the following negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static ngtcp2_ssize conn_write_path_challenge(ngtcp2_conn *conn, + ngtcp2_path *path, + ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + ngtcp2_tstamp ts) { + ngtcp2_ssize nwrite; + ngtcp2_tstamp expiry; + ngtcp2_pv *pv = conn->pv; + ngtcp2_frame lfr; + ngtcp2_duration timeout; + uint8_t flags; + uint64_t tx_left; + int rv; + + if (ngtcp2_pv_validation_timed_out(pv, ts)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PTV, + "path validation was timed out"); + rv = conn_on_path_validation_failed(conn, pv, ts); + if (rv != 0) { + return rv; + } + + /* We might set path to the one which we just failed validate. + Set it to the current path here. */ + if (path) { + ngtcp2_path_copy(path, &conn->dcid.current.ps.path); + } + + return 0; + } + + ngtcp2_pv_handle_entry_expiry(pv, ts); + + if (!ngtcp2_pv_should_send_probe(pv)) { + return 0; + } + + rv = conn_call_get_path_challenge_data(conn, lfr.path_challenge.data); + if (rv != 0) { + return rv; + } + + lfr.type = NGTCP2_FRAME_PATH_CHALLENGE; + + timeout = conn_compute_pto(conn, &conn->pktns); + timeout = ngtcp2_max(timeout, 3 * conn->cstat.initial_rtt); + expiry = ts + timeout * (1ULL << pv->round); + + destlen = ngtcp2_min(destlen, NGTCP2_MAX_UDP_PAYLOAD_SIZE); + + if (conn->server) { + if (!(pv->dcid.flags & NGTCP2_DCID_FLAG_PATH_VALIDATED)) { + tx_left = conn_server_tx_left(conn, &pv->dcid); + destlen = (size_t)ngtcp2_min((uint64_t)destlen, tx_left); + if (destlen == 0) { + return 0; + } + } + + if (destlen < NGTCP2_MAX_UDP_PAYLOAD_SIZE) { + flags = NGTCP2_PV_ENTRY_FLAG_UNDERSIZED; + } else { + flags = NGTCP2_PV_ENTRY_FLAG_NONE; + } + } else { + flags = NGTCP2_PV_ENTRY_FLAG_NONE; + } + + ngtcp2_pv_add_entry(pv, lfr.path_challenge.data, expiry, flags, ts); + + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_1RTT, NGTCP2_WRITE_PKT_FLAG_NONE, + &pv->dcid.cid, &lfr, + NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING | NGTCP2_RTB_ENTRY_FLAG_PTO_ELICITING, + &pv->dcid.ps.path, ts); + if (nwrite <= 0) { + return nwrite; + } + + if (path) { + ngtcp2_path_copy(path, &pv->dcid.ps.path); + } + + if (ngtcp2_path_eq(&pv->dcid.ps.path, &conn->dcid.current.ps.path)) { + conn->dcid.current.bytes_sent += (uint64_t)nwrite; + } else { + pv->dcid.bytes_sent += (uint64_t)nwrite; + } + + return nwrite; +} + +/* + * conn_write_path_response writes a packet which includes + * PATH_RESPONSE frame into |dest| of length |destlen|. + * + * This function returns the number of bytes written to |dest|, or one + * of the following negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static ngtcp2_ssize conn_write_path_response(ngtcp2_conn *conn, + ngtcp2_path *path, + ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, ngtcp2_tstamp ts) { + ngtcp2_pv *pv = conn->pv; + ngtcp2_path_challenge_entry *pcent = NULL; + ngtcp2_dcid *dcid = NULL; + ngtcp2_frame lfr; + ngtcp2_ssize nwrite; + int rv; + uint64_t tx_left; + + for (; ngtcp2_ringbuf_len(&conn->rx.path_challenge.rb);) { + pcent = ngtcp2_ringbuf_get(&conn->rx.path_challenge.rb, 0); + + if (ngtcp2_path_eq(&conn->dcid.current.ps.path, &pcent->ps.path)) { + /* Send PATH_RESPONSE from conn_write_pkt. */ + return 0; + } + + if (pv) { + if (ngtcp2_path_eq(&pv->dcid.ps.path, &pcent->ps.path)) { + dcid = &pv->dcid; + break; + } + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + ngtcp2_path_eq(&pv->fallback_dcid.ps.path, &pcent->ps.path)) { + dcid = &pv->fallback_dcid; + break; + } + } + + if (conn->server) { + break; + } + + /* Client does not expect to respond to path validation against + unknown path */ + ngtcp2_ringbuf_pop_front(&conn->rx.path_challenge.rb); + pcent = NULL; + } + + if (pcent == NULL) { + return 0; + } + + if (dcid == NULL) { + /* client is expected to have |path| in conn->dcid.current or + conn->pv. */ + assert(conn->server); + + rv = conn_bind_dcid(conn, &dcid, &pcent->ps.path, ts); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + return 0; + } + } + + destlen = ngtcp2_min(destlen, NGTCP2_MAX_UDP_PAYLOAD_SIZE); + + if (conn->server && !(dcid->flags & NGTCP2_DCID_FLAG_PATH_VALIDATED)) { + tx_left = conn_server_tx_left(conn, dcid); + destlen = (size_t)ngtcp2_min((uint64_t)destlen, tx_left); + if (destlen == 0) { + return 0; + } + } + + lfr.type = NGTCP2_FRAME_PATH_RESPONSE; + memcpy(lfr.path_response.data, pcent->data, sizeof(lfr.path_response.data)); + + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_1RTT, NGTCP2_WRITE_PKT_FLAG_NONE, + &dcid->cid, &lfr, NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING, &pcent->ps.path, + ts); + if (nwrite <= 0) { + return nwrite; + } + + if (path) { + ngtcp2_path_copy(path, &pcent->ps.path); + } + + ngtcp2_ringbuf_pop_front(&conn->rx.path_challenge.rb); + + dcid->bytes_sent += (uint64_t)nwrite; + + return nwrite; +} + +ngtcp2_ssize ngtcp2_conn_write_pkt_versioned(ngtcp2_conn *conn, + ngtcp2_path *path, + int pkt_info_version, + ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, ngtcp2_tstamp ts) { + return ngtcp2_conn_writev_stream_versioned( + conn, path, pkt_info_version, pi, dest, destlen, + /* pdatalen = */ NULL, NGTCP2_WRITE_STREAM_FLAG_NONE, + /* stream_id = */ -1, + /* datav = */ NULL, /* datavcnt = */ 0, ts); +} + +/* + * conn_on_version_negotiation is called when Version Negotiation + * packet is received. The function decodes the data in the buffer + * pointed by |payload| whose length is |payloadlen| as Version + * Negotiation packet payload. The packet header is given in |hd|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_INVALID_ARGUMENT + * Packet payload is badly formatted. + */ +static int conn_on_version_negotiation(ngtcp2_conn *conn, + const ngtcp2_pkt_hd *hd, + const uint8_t *payload, + size_t payloadlen) { + uint32_t sv[16]; + uint32_t *p; + int rv = 0; + size_t nsv; + size_t i; + + if (payloadlen % sizeof(uint32_t)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + /* Version Negotiation packet is ignored if client has reacted upon + Version Negotiation packet. */ + if (conn->local.settings.original_version != conn->client_chosen_version) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + if (payloadlen > sizeof(sv)) { + p = ngtcp2_mem_malloc(conn->mem, payloadlen); + if (p == NULL) { + return NGTCP2_ERR_NOMEM; + } + } else { + p = sv; + } + + nsv = ngtcp2_pkt_decode_version_negotiation(p, payload, payloadlen); + + ngtcp2_log_rx_vn(&conn->log, hd, p, nsv); + + ngtcp2_qlog_version_negotiation_pkt_received(&conn->qlog, hd, p, nsv); + + if (!ngtcp2_is_reserved_version(conn->local.settings.original_version)) { + for (i = 0; i < nsv; ++i) { + if (p[i] == conn->local.settings.original_version) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "ignore Version Negotiation because it contains the " + "original version"); + + rv = NGTCP2_ERR_INVALID_ARGUMENT; + goto fin; + } + } + } + + rv = conn_call_recv_version_negotiation(conn, hd, p, nsv); + if (rv != 0) { + goto fin; + } + +fin: + if (p != sv) { + ngtcp2_mem_free(conn->mem, p); + } + + return rv; +} + +static uint64_t conn_tx_strmq_first_cycle(ngtcp2_conn *conn) { + ngtcp2_strm *strm; + + if (ngtcp2_pq_empty(&conn->tx.strmq)) { + return 0; + } + + strm = ngtcp2_struct_of(ngtcp2_pq_top(&conn->tx.strmq), ngtcp2_strm, pe); + return strm->cycle; +} + +uint64_t ngtcp2_conn_tx_strmq_first_cycle(ngtcp2_conn *conn) { + ngtcp2_strm *strm; + + if (ngtcp2_pq_empty(&conn->tx.strmq)) { + return 0; + } + + strm = ngtcp2_struct_of(ngtcp2_pq_top(&conn->tx.strmq), ngtcp2_strm, pe); + return strm->cycle; +} + +int ngtcp2_conn_resched_frames(ngtcp2_conn *conn, ngtcp2_pktns *pktns, + ngtcp2_frame_chain **pfrc) { + ngtcp2_frame_chain **first = pfrc; + ngtcp2_frame_chain *frc; + ngtcp2_stream *sfr; + ngtcp2_strm *strm; + int rv; + int streamfrq_empty; + + if (*pfrc == NULL) { + return 0; + } + + for (; *pfrc;) { + switch ((*pfrc)->fr.type) { + case NGTCP2_FRAME_STREAM: + frc = *pfrc; + + *pfrc = frc->next; + frc->next = NULL; + sfr = &frc->fr.stream; + + strm = ngtcp2_conn_find_stream(conn, sfr->stream_id); + if (!strm) { + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + break; + } + streamfrq_empty = ngtcp2_strm_streamfrq_empty(strm); + rv = ngtcp2_strm_streamfrq_push(strm, frc); + if (rv != 0) { + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + if (!ngtcp2_strm_is_tx_queued(strm)) { + strm->cycle = conn_tx_strmq_first_cycle(conn); + rv = ngtcp2_conn_tx_strmq_push(conn, strm); + if (rv != 0) { + return rv; + } + } + if (streamfrq_empty) { + ++conn->tx.strmq_nretrans; + } + break; + case NGTCP2_FRAME_CRYPTO: + frc = *pfrc; + + *pfrc = frc->next; + frc->next = NULL; + + rv = ngtcp2_ksl_insert(&pktns->crypto.tx.frq, NULL, + &frc->fr.crypto.offset, frc); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + break; + default: + pfrc = &(*pfrc)->next; + } + } + + *pfrc = pktns->tx.frq; + pktns->tx.frq = *first; + + return 0; +} + +/* + * conn_on_retry is called when Retry packet is received. The + * function decodes the data in the buffer pointed by |pkt| whose + * length is |pktlen| as Retry packet. The length of long packet + * header is given in |hdpktlen|. |pkt| includes packet header. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_INVALID_ARGUMENT + * Packet payload is badly formatted. + * NGTCP2_ERR_PROTO + * ODCID does not match; or Token is empty. + */ +static int conn_on_retry(ngtcp2_conn *conn, const ngtcp2_pkt_hd *hd, + size_t hdpktlen, const uint8_t *pkt, size_t pktlen, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_pkt_retry retry; + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_rtb *rtb = &conn->pktns.rtb; + ngtcp2_rtb *in_rtb; + uint8_t cidbuf[sizeof(retry.odcid.data) * 2 + 1]; + uint8_t *token; + + if (!in_pktns || conn->flags & NGTCP2_CONN_FLAG_RECV_RETRY) { + return 0; + } + + in_rtb = &in_pktns->rtb; + + rv = ngtcp2_pkt_decode_retry(&retry, pkt + hdpktlen, pktlen - hdpktlen); + if (rv != 0) { + return rv; + } + + retry.odcid = conn->dcid.current.cid; + + rv = ngtcp2_pkt_verify_retry_tag( + conn->client_chosen_version, &retry, pkt, pktlen, conn->callbacks.encrypt, + &conn->crypto.retry_aead, &conn->crypto.retry_aead_ctx); + if (rv != 0) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "unable to verify Retry packet integrity"); + return rv; + } + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, "odcid=0x%s", + (const char *)ngtcp2_encode_hex(cidbuf, retry.odcid.data, + retry.odcid.datalen)); + + if (retry.tokenlen == 0) { + return NGTCP2_ERR_PROTO; + } + + if (ngtcp2_cid_eq(&conn->dcid.current.cid, &hd->scid)) { + return 0; + } + + ngtcp2_qlog_retry_pkt_received(&conn->qlog, hd, &retry); + + /* DCID must be updated before invoking callback because client + generates new initial keys there. */ + conn->dcid.current.cid = hd->scid; + conn->retry_scid = hd->scid; + + conn->flags |= NGTCP2_CONN_FLAG_RECV_RETRY; + + rv = conn_call_recv_retry(conn, hd); + if (rv != 0) { + return rv; + } + + conn->state = NGTCP2_CS_CLIENT_INITIAL; + + /* Just freeing memory is dangerous because we might free twice. */ + + rv = ngtcp2_rtb_remove_all(rtb, conn, &conn->pktns, &conn->cstat); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_rtb_remove_all(in_rtb, conn, in_pktns, &conn->cstat); + if (rv != 0) { + return rv; + } + + ngtcp2_mem_free(conn->mem, (uint8_t *)conn->local.settings.token); + conn->local.settings.token = NULL; + conn->local.settings.tokenlen = 0; + + token = ngtcp2_mem_malloc(conn->mem, retry.tokenlen); + if (token == NULL) { + return NGTCP2_ERR_NOMEM; + } + + ngtcp2_cpymem(token, retry.token, retry.tokenlen); + + conn->local.settings.token = token; + conn->local.settings.tokenlen = retry.tokenlen; + + reset_conn_stat_recovery(&conn->cstat); + conn_reset_congestion_state(conn, ts); + conn_reset_ecn_validation_state(conn); + + return 0; +} + +int ngtcp2_conn_detect_lost_pkt(ngtcp2_conn *conn, ngtcp2_pktns *pktns, + ngtcp2_conn_stat *cstat, ngtcp2_tstamp ts) { + return ngtcp2_rtb_detect_lost_pkt(&pktns->rtb, conn, pktns, cstat, ts); +} + +/* + * conn_recv_ack processes received ACK frame |fr|. |pkt_ts| is the + * timestamp when packet is received. |ts| should be the current + * time. Usually they are the same, but for buffered packets, + * |pkt_ts| would be earlier than |ts|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_ACK_FRAME + * ACK frame is malformed. + * NGTCP2_ERR_PROTO + * |fr| acknowledges a packet this endpoint has not sent. + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed. + */ +static int conn_recv_ack(ngtcp2_conn *conn, ngtcp2_pktns *pktns, ngtcp2_ack *fr, + ngtcp2_tstamp pkt_ts, ngtcp2_tstamp ts) { + int rv; + ngtcp2_frame_chain *frc = NULL; + ngtcp2_ssize num_acked; + ngtcp2_conn_stat *cstat = &conn->cstat; + + if (pktns->tx.last_pkt_num < fr->largest_ack) { + return NGTCP2_ERR_PROTO; + } + + rv = ngtcp2_pkt_validate_ack(fr); + if (rv != 0) { + return rv; + } + + ngtcp2_acktr_recv_ack(&pktns->acktr, fr); + + num_acked = ngtcp2_rtb_recv_ack(&pktns->rtb, fr, &conn->cstat, conn, pktns, + pkt_ts, ts); + if (num_acked < 0) { + /* TODO assert this */ + assert(ngtcp2_err_is_fatal((int)num_acked)); + ngtcp2_frame_chain_list_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return (int)num_acked; + } + + if (num_acked == 0) { + return 0; + } + + pktns->rtb.probe_pkt_left = 0; + + if (cstat->pto_count && + (conn->server || (conn->flags & NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED))) { + /* Reset PTO count but no less than 2 to avoid frequent probe + packet transmission. */ + cstat->pto_count = ngtcp2_min(cstat->pto_count, 2); + } + + ngtcp2_conn_set_loss_detection_timer(conn, ts); + + return 0; +} + +/* + * conn_assign_recved_ack_delay_unscaled assigns + * fr->ack_delay_unscaled. + */ +static void assign_recved_ack_delay_unscaled(ngtcp2_ack *fr, + uint64_t ack_delay_exponent) { + fr->ack_delay_unscaled = + fr->ack_delay * (1ULL << ack_delay_exponent) * NGTCP2_MICROSECONDS; +} + +/* + * conn_recv_max_stream_data processes received MAX_STREAM_DATA frame + * |fr|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_STREAM_STATE + * Stream ID indicates that it is a local stream, and the local + * endpoint has not initiated it; or stream is peer initiated + * unidirectional stream. + * NGTCP2_ERR_STREAM_LIMIT + * Stream ID exceeds allowed limit. + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_recv_max_stream_data(ngtcp2_conn *conn, + const ngtcp2_max_stream_data *fr) { + ngtcp2_strm *strm; + ngtcp2_idtr *idtr; + int local_stream = conn_local_stream(conn, fr->stream_id); + int bidi = bidi_stream(fr->stream_id); + int rv; + + if (bidi) { + if (local_stream) { + if (conn->local.bidi.next_stream_id <= fr->stream_id) { + return NGTCP2_ERR_STREAM_STATE; + } + } else if (conn->remote.bidi.max_streams < + ngtcp2_ord_stream_id(fr->stream_id)) { + return NGTCP2_ERR_STREAM_LIMIT; + } + + idtr = &conn->remote.bidi.idtr; + } else { + if (!local_stream || conn->local.uni.next_stream_id <= fr->stream_id) { + return NGTCP2_ERR_STREAM_STATE; + } + + idtr = &conn->remote.uni.idtr; + } + + strm = ngtcp2_conn_find_stream(conn, fr->stream_id); + if (strm == NULL) { + if (local_stream) { + /* Stream has been closed. */ + return 0; + } + + rv = ngtcp2_idtr_open(idtr, fr->stream_id); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + assert(rv == NGTCP2_ERR_STREAM_IN_USE); + /* Stream has been closed. */ + return 0; + } + + strm = ngtcp2_objalloc_strm_get(&conn->strm_objalloc); + if (strm == NULL) { + return NGTCP2_ERR_NOMEM; + } + rv = ngtcp2_conn_init_stream(conn, strm, fr->stream_id, NULL); + if (rv != 0) { + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm); + return rv; + } + + rv = conn_call_stream_open(conn, strm); + if (rv != 0) { + return rv; + } + } + + if (strm->tx.max_offset < fr->max_stream_data) { + strm->tx.max_offset = fr->max_stream_data; + + /* Don't call callback if stream is half-closed local */ + if (strm->flags & NGTCP2_STRM_FLAG_SHUT_WR) { + return 0; + } + + rv = conn_call_extend_max_stream_data(conn, strm, fr->stream_id, + fr->max_stream_data); + if (rv != 0) { + return rv; + } + } + + return 0; +} + +/* + * conn_recv_max_data processes received MAX_DATA frame |fr|. + */ +static void conn_recv_max_data(ngtcp2_conn *conn, const ngtcp2_max_data *fr) { + conn->tx.max_offset = ngtcp2_max(conn->tx.max_offset, fr->max_data); +} + +/* + * conn_buffer_pkt buffers |pkt| of length |pktlen|, chaining it from + * |*ppc|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_buffer_pkt(ngtcp2_conn *conn, ngtcp2_pktns *pktns, + const ngtcp2_path *path, const ngtcp2_pkt_info *pi, + const uint8_t *pkt, size_t pktlen, size_t dgramlen, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_pkt_chain **ppc = &pktns->rx.buffed_pkts, *pc; + size_t i; + for (i = 0; *ppc && i < NGTCP2_MAX_NUM_BUFFED_RX_PKTS; + ppc = &(*ppc)->next, ++i) + ; + + if (i == NGTCP2_MAX_NUM_BUFFED_RX_PKTS) { + return 0; + } + + rv = + ngtcp2_pkt_chain_new(&pc, path, pi, pkt, pktlen, dgramlen, ts, conn->mem); + if (rv != 0) { + return rv; + } + + *ppc = pc; + + return 0; +} + +static int ensure_decrypt_buffer(ngtcp2_vec *vec, size_t n, size_t initial, + const ngtcp2_mem *mem) { + uint8_t *nbuf; + size_t len; + + if (vec->len >= n) { + return 0; + } + + len = vec->len == 0 ? initial : vec->len * 2; + for (; len < n; len *= 2) + ; + nbuf = ngtcp2_mem_realloc(mem, vec->base, len); + if (nbuf == NULL) { + return NGTCP2_ERR_NOMEM; + } + vec->base = nbuf; + vec->len = len; + + return 0; +} + +/* + * conn_ensure_decrypt_hp_buffer ensures that + * conn->crypto.decrypt_hp_buf has at least |n| bytes space. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_ensure_decrypt_hp_buffer(ngtcp2_conn *conn, size_t n) { + return ensure_decrypt_buffer(&conn->crypto.decrypt_hp_buf, n, 256, conn->mem); +} + +/* + * conn_ensure_decrypt_buffer ensures that conn->crypto.decrypt_buf + * has at least |n| bytes space. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_ensure_decrypt_buffer(ngtcp2_conn *conn, size_t n) { + return ensure_decrypt_buffer(&conn->crypto.decrypt_buf, n, 2048, conn->mem); +} + +/* + * decrypt_pkt decrypts the data pointed by |payload| whose length is + * |payloadlen|, and writes plaintext data to the buffer pointed by + * |dest|. The buffer pointed by |aad| is the Additional + * Authenticated Data, and its length is |aadlen|. |pkt_num| is used + * to create a nonce. |ckm| is the cryptographic key, and iv to use. + * |decrypt| is a callback function which actually decrypts a packet. + * + * This function returns the number of bytes written in |dest| if it + * succeeds, or one of the following negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed. + * NGTCP2_ERR_DECRYPT + * Failed to decrypt a packet. + */ +static ngtcp2_ssize decrypt_pkt(uint8_t *dest, const ngtcp2_crypto_aead *aead, + const uint8_t *payload, size_t payloadlen, + const uint8_t *aad, size_t aadlen, + int64_t pkt_num, ngtcp2_crypto_km *ckm, + ngtcp2_decrypt decrypt) { + /* TODO nonce is limited to 64 bytes. */ + uint8_t nonce[64]; + int rv; + + assert(sizeof(nonce) >= ckm->iv.len); + + ngtcp2_crypto_create_nonce(nonce, ckm->iv.base, ckm->iv.len, pkt_num); + + rv = decrypt(dest, aead, &ckm->aead_ctx, payload, payloadlen, nonce, + ckm->iv.len, aad, aadlen); + + if (rv != 0) { + if (rv == NGTCP2_ERR_DECRYPT) { + return rv; + } + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + assert(payloadlen >= aead->max_overhead); + + return (ngtcp2_ssize)(payloadlen - aead->max_overhead); +} + +/* + * decrypt_hp decryptes packet header. The packet number starts at + * |pkt| + |pkt_num_offset|. The entire plaintext QUIC packet header + * will be written to the buffer pointed by |dest| whose capacity is + * |destlen|. + * + * This function returns the number of bytes written to |dest|, or one + * of the following negative error codes: + * + * NGTCP2_ERR_PROTO + * Packet is badly formatted + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed; or it does not return + * expected result. + */ +static ngtcp2_ssize +decrypt_hp(ngtcp2_pkt_hd *hd, uint8_t *dest, const ngtcp2_crypto_cipher *hp, + const uint8_t *pkt, size_t pktlen, size_t pkt_num_offset, + const ngtcp2_crypto_cipher_ctx *hp_ctx, ngtcp2_hp_mask hp_mask) { + size_t sample_offset; + uint8_t *p = dest; + uint8_t mask[NGTCP2_HP_SAMPLELEN]; + size_t i; + int rv; + + assert(hp_mask); + + if (pkt_num_offset + 4 + NGTCP2_HP_SAMPLELEN > pktlen) { + return NGTCP2_ERR_PROTO; + } + + p = ngtcp2_cpymem(p, pkt, pkt_num_offset); + + sample_offset = pkt_num_offset + 4; + + rv = hp_mask(mask, hp, hp_ctx, pkt + sample_offset); + if (rv != 0) { + return NGTCP2_ERR_CALLBACK_FAILURE; + } + + if (hd->flags & NGTCP2_PKT_FLAG_LONG_FORM) { + dest[0] = (uint8_t)(dest[0] ^ (mask[0] & 0x0f)); + } else { + dest[0] = (uint8_t)(dest[0] ^ (mask[0] & 0x1f)); + if (dest[0] & NGTCP2_SHORT_KEY_PHASE_BIT) { + hd->flags |= NGTCP2_PKT_FLAG_KEY_PHASE; + } + } + + hd->pkt_numlen = (size_t)((dest[0] & NGTCP2_PKT_NUMLEN_MASK) + 1); + + for (i = 0; i < hd->pkt_numlen; ++i) { + *p++ = *(pkt + pkt_num_offset + i) ^ mask[i + 1]; + } + + hd->pkt_num = ngtcp2_get_pkt_num(p - hd->pkt_numlen, hd->pkt_numlen); + + return p - dest; +} + +/* + * conn_emit_pending_crypto_data delivers pending stream data to the + * application due to packet reordering. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed + * NGTCP2_ERR_CRYPTO + * TLS backend reported error + */ +static int conn_emit_pending_crypto_data(ngtcp2_conn *conn, + ngtcp2_crypto_level crypto_level, + ngtcp2_strm *strm, + uint64_t rx_offset) { + size_t datalen; + const uint8_t *data; + int rv; + uint64_t offset; + + if (!strm->rx.rob) { + return 0; + } + + for (;;) { + datalen = ngtcp2_rob_data_at(strm->rx.rob, &data, rx_offset); + if (datalen == 0) { + assert(rx_offset == ngtcp2_strm_rx_offset(strm)); + return 0; + } + + offset = rx_offset; + rx_offset += datalen; + + rv = conn_call_recv_crypto_data(conn, crypto_level, offset, data, datalen); + if (rv != 0) { + return rv; + } + + ngtcp2_rob_pop(strm->rx.rob, rx_offset - datalen, datalen); + } +} + +/* + * conn_recv_connection_close is called when CONNECTION_CLOSE or + * APPLICATION_CLOSE frame is received. + */ +static int conn_recv_connection_close(ngtcp2_conn *conn, + ngtcp2_connection_close *fr) { + ngtcp2_connection_close_error *ccerr = &conn->rx.ccerr; + + conn->state = NGTCP2_CS_DRAINING; + if (fr->type == NGTCP2_FRAME_CONNECTION_CLOSE) { + ccerr->type = NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_TRANSPORT; + } else { + ccerr->type = NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_APPLICATION; + } + ccerr->error_code = fr->error_code; + ccerr->frame_type = fr->frame_type; + + if (!fr->reasonlen) { + ccerr->reasonlen = 0; + + return 0; + } + + if (ccerr->reason == NULL) { + ccerr->reason = ngtcp2_mem_malloc( + conn->mem, NGTCP2_CONNECTION_CLOSE_ERROR_MAX_REASONLEN); + if (ccerr->reason == NULL) { + return NGTCP2_ERR_NOMEM; + } + } + + ccerr->reasonlen = + ngtcp2_min(fr->reasonlen, NGTCP2_CONNECTION_CLOSE_ERROR_MAX_REASONLEN); + ngtcp2_cpymem((uint8_t *)ccerr->reason, fr->reason, ccerr->reasonlen); + + return 0; +} + +static void conn_recv_path_challenge(ngtcp2_conn *conn, const ngtcp2_path *path, + ngtcp2_path_challenge *fr) { + ngtcp2_path_challenge_entry *ent; + + /* client only responds to PATH_CHALLENGE from the current path or + path which client is migrating to. */ + if (!conn->server && !ngtcp2_path_eq(&conn->dcid.current.ps.path, path) && + (!conn->pv || !ngtcp2_path_eq(&conn->pv->dcid.ps.path, path))) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "discard PATH_CHALLENGE from the path which is not current " + "or endpoint is migrating to"); + return; + } + + ent = ngtcp2_ringbuf_push_front(&conn->rx.path_challenge.rb); + ngtcp2_path_challenge_entry_init(ent, path, fr->data); +} + +/* + * conn_reset_congestion_state resets congestion state. + */ +static void conn_reset_congestion_state(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + conn_reset_conn_stat_cc(conn, &conn->cstat); + + conn->cc.reset(&conn->cc, &conn->cstat, ts); + + if (conn->hs_pktns) { + ngtcp2_rtb_reset_cc_state(&conn->hs_pktns->rtb, + conn->hs_pktns->tx.last_pkt_num + 1); + } + ngtcp2_rtb_reset_cc_state(&conn->pktns.rtb, conn->pktns.tx.last_pkt_num + 1); + ngtcp2_rst_init(&conn->rst); + + conn->tx.pacing.next_ts = UINT64_MAX; +} + +static int conn_recv_path_response(ngtcp2_conn *conn, ngtcp2_path_response *fr, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_duration pto, timeout; + ngtcp2_pv *pv = conn->pv, *npv; + uint8_t ent_flags; + + if (!pv) { + return 0; + } + + rv = ngtcp2_pv_validate(pv, &ent_flags, fr->data); + if (rv != 0) { + assert(!ngtcp2_err_is_fatal(rv)); + + return 0; + } + + if (!(pv->flags & NGTCP2_PV_FLAG_DONT_CARE)) { + if (!(pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE)) { + if (pv->dcid.seq != conn->dcid.current.seq) { + assert(conn->dcid.current.cid.datalen); + + rv = conn_retire_dcid(conn, &conn->dcid.current, ts); + if (rv != 0) { + return rv; + } + ngtcp2_dcid_copy(&conn->dcid.current, &pv->dcid); + } + conn_reset_congestion_state(conn, ts); + conn_reset_ecn_validation_state(conn); + } + + if (ngtcp2_path_eq(&pv->dcid.ps.path, &conn->dcid.current.ps.path)) { + conn->dcid.current.flags |= NGTCP2_DCID_FLAG_PATH_VALIDATED; + + if (!conn->local.settings.no_pmtud) { + ngtcp2_conn_stop_pmtud(conn); + + if (!(pv->flags & NGTCP2_PV_ENTRY_FLAG_UNDERSIZED)) { + rv = conn_start_pmtud(conn); + if (rv != 0) { + return rv; + } + } + } + } + + rv = conn_call_path_validation(conn, pv, + NGTCP2_PATH_VALIDATION_RESULT_SUCCESS); + if (rv != 0) { + return rv; + } + } + + if (pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) { + pto = conn_compute_pto(conn, &conn->pktns); + timeout = 3 * ngtcp2_max(pto, pv->fallback_pto); + + if (ent_flags & NGTCP2_PV_ENTRY_FLAG_UNDERSIZED) { + assert(conn->server); + + /* Validate path again */ + rv = ngtcp2_pv_new(&npv, &pv->dcid, timeout, + NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE | + NGTCP2_PV_FLAG_MTU_PROBE, + &conn->log, conn->mem); + if (rv != 0) { + return rv; + } + + npv->dcid.flags |= NGTCP2_DCID_FLAG_PATH_VALIDATED; + ngtcp2_dcid_copy(&npv->fallback_dcid, &pv->fallback_dcid); + npv->fallback_pto = pv->fallback_pto; + } else { + rv = ngtcp2_pv_new(&npv, &pv->fallback_dcid, timeout, + NGTCP2_PV_FLAG_DONT_CARE, &conn->log, conn->mem); + if (rv != 0) { + return rv; + } + } + + /* Unset the flag bit so that conn_stop_pv does not retire + DCID. */ + pv->flags &= (uint8_t)~NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE; + + rv = conn_stop_pv(conn, ts); + if (rv != 0) { + ngtcp2_pv_del(npv); + return rv; + } + + conn->pv = npv; + + return 0; + } + + return conn_stop_pv(conn, ts); +} + +/* + * pkt_num_bits returns the number of bits available when packet + * number is encoded in |pkt_numlen| bytes. + */ +static size_t pkt_num_bits(size_t pkt_numlen) { + switch (pkt_numlen) { + case 1: + return 8; + case 2: + return 16; + case 3: + return 24; + case 4: + return 32; + default: + ngtcp2_unreachable(); + } +} + +/* + * pktns_pkt_num_is_duplicate returns nonzero if |pkt_num| is + * duplicated packet number. + */ +static int pktns_pkt_num_is_duplicate(ngtcp2_pktns *pktns, int64_t pkt_num) { + return ngtcp2_gaptr_is_pushed(&pktns->rx.pngap, (uint64_t)pkt_num, 1); +} + +/* + * pktns_commit_recv_pkt_num marks packet number |pkt_num| as + * received. + */ +static int pktns_commit_recv_pkt_num(ngtcp2_pktns *pktns, int64_t pkt_num, + int ack_eliciting, ngtcp2_tstamp ts) { + int rv; + + if (ack_eliciting && pktns->rx.max_ack_eliciting_pkt_num + 1 != pkt_num) { + ngtcp2_acktr_immediate_ack(&pktns->acktr); + } + if (pktns->rx.max_pkt_num < pkt_num) { + pktns->rx.max_pkt_num = pkt_num; + pktns->rx.max_pkt_ts = ts; + } + if (ack_eliciting && pktns->rx.max_ack_eliciting_pkt_num < pkt_num) { + pktns->rx.max_ack_eliciting_pkt_num = pkt_num; + } + + rv = ngtcp2_gaptr_push(&pktns->rx.pngap, (uint64_t)pkt_num, 1); + if (rv != 0) { + return rv; + } + + if (ngtcp2_ksl_len(&pktns->rx.pngap.gap) > 256) { + ngtcp2_gaptr_drop_first_gap(&pktns->rx.pngap); + } + + return 0; +} + +/* + * verify_token verifies |hd| contains |token| in its token field. It + * returns 0 if it succeeds, or NGTCP2_ERR_PROTO. + */ +static int verify_token(const uint8_t *token, size_t tokenlen, + const ngtcp2_pkt_hd *hd) { + if (tokenlen == hd->tokenlen && ngtcp2_cmemeq(token, hd->token, tokenlen)) { + return 0; + } + return NGTCP2_ERR_PROTO; +} + +static void pktns_increase_ecn_counts(ngtcp2_pktns *pktns, + const ngtcp2_pkt_info *pi) { + switch (pi->ecn & NGTCP2_ECN_MASK) { + case NGTCP2_ECN_ECT_0: + ++pktns->rx.ecn.ect0; + break; + case NGTCP2_ECN_ECT_1: + ++pktns->rx.ecn.ect1; + break; + case NGTCP2_ECN_CE: + ++pktns->rx.ecn.ce; + break; + } +} + +/* + * vneg_available_versions_includes returns nonzero if + * |available_versions| of length |available_versionslen| includes + * |version|. |available_versions| is the wire image of + * available_versions field of version_information transport + * parameter, and each version is encoded in network byte order. + */ +static int vneg_available_versions_includes(const uint8_t *available_versions, + size_t available_versionslen, + uint32_t version) { + size_t i; + uint32_t v; + + assert(!(available_versionslen & 0x3)); + + if (available_versionslen == 0) { + return 0; + } + + for (i = 0; i < available_versionslen; i += sizeof(uint32_t)) { + available_versions = ngtcp2_get_uint32(&v, available_versions); + + if (version == v) { + return 1; + } + } + + return 0; +} + +static int conn_recv_crypto(ngtcp2_conn *conn, ngtcp2_crypto_level crypto_level, + ngtcp2_strm *strm, const ngtcp2_crypto *fr); + +static ngtcp2_ssize conn_recv_pkt(ngtcp2_conn *conn, const ngtcp2_path *path, + const ngtcp2_pkt_info *pi, const uint8_t *pkt, + size_t pktlen, size_t dgramlen, + ngtcp2_tstamp pkt_ts, ngtcp2_tstamp ts); + +static int conn_process_buffered_protected_pkt(ngtcp2_conn *conn, + ngtcp2_pktns *pktns, + ngtcp2_tstamp ts); + +/* + * conn_recv_handshake_pkt processes received packet |pkt| whose + * length is |pktlen| during handshake period. The buffer pointed by + * |pkt| might contain multiple packets. This function only processes + * one packet. |pkt_ts| is the timestamp when packet is received. + * |ts| should be the current time. Usually they are the same, but + * for buffered packets, |pkt_ts| would be earlier than |ts|. + * + * This function returns the number of bytes it reads if it succeeds, + * or one of the following negative error codes: + * + * NGTCP2_ERR_RECV_VERSION_NEGOTIATION + * Version Negotiation packet is received. + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_DISCARD_PKT + * Packet was discarded because plain text header was malformed; + * or its payload could not be decrypted. + * NGTCP2_ERR_FRAME_FORMAT + * Frame is badly formatted + * NGTCP2_ERR_ACK_FRAME + * ACK frame is malformed. + * NGTCP2_ERR_CRYPTO + * TLS stack reported error. + * NGTCP2_ERR_PROTO + * Generic QUIC protocol error. + * + * In addition to the above error codes, error codes returned from + * conn_recv_pkt are also returned. + */ +static ngtcp2_ssize +conn_recv_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_path *path, + const ngtcp2_pkt_info *pi, const uint8_t *pkt, + size_t pktlen, size_t dgramlen, ngtcp2_tstamp pkt_ts, + ngtcp2_tstamp ts) { + ngtcp2_ssize nread; + ngtcp2_pkt_hd hd; + ngtcp2_max_frame mfr; + ngtcp2_frame *fr = &mfr.fr; + int rv; + int require_ack = 0; + size_t hdpktlen; + const uint8_t *payload; + size_t payloadlen; + ngtcp2_ssize nwrite; + ngtcp2_crypto_aead *aead; + ngtcp2_crypto_cipher *hp; + ngtcp2_crypto_km *ckm; + ngtcp2_crypto_cipher_ctx *hp_ctx; + ngtcp2_hp_mask hp_mask; + ngtcp2_decrypt decrypt; + ngtcp2_pktns *pktns; + ngtcp2_strm *crypto; + ngtcp2_crypto_level crypto_level; + int invalid_reserved_bits = 0; + + if (pktlen == 0) { + return 0; + } + + if (!(pkt[0] & NGTCP2_HEADER_FORM_BIT)) { + if (conn->state == NGTCP2_CS_SERVER_INITIAL) { + /* Ignore 1RTT packet unless server's first Handshake packet has + been transmitted. */ + return (ngtcp2_ssize)pktlen; + } + + if (conn->pktns.crypto.rx.ckm) { + return 0; + } + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "buffering 1RTT packet len=%zu", pktlen); + + rv = conn_buffer_pkt(conn, &conn->pktns, path, pi, pkt, pktlen, dgramlen, + ts); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + return (ngtcp2_ssize)pktlen; + } + + nread = ngtcp2_pkt_decode_hd_long(&hd, pkt, pktlen); + if (nread < 0) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (hd.type == NGTCP2_PKT_VERSION_NEGOTIATION) { + hdpktlen = (size_t)nread; + + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + + if (conn->server) { + return NGTCP2_ERR_DISCARD_PKT; + } + + /* Receiving Version Negotiation packet after getting Handshake + packet from server is invalid. */ + if (conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (!ngtcp2_cid_eq(&conn->oscid, &hd.dcid)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched DCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + + if (!ngtcp2_cid_eq(&conn->dcid.current.cid, &hd.scid)) { + /* Just discard invalid Version Negotiation packet */ + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched SCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + rv = conn_on_version_negotiation(conn, &hd, pkt + hdpktlen, + pktlen - hdpktlen); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + return NGTCP2_ERR_DISCARD_PKT; + } + return NGTCP2_ERR_RECV_VERSION_NEGOTIATION; + } else if (hd.type == NGTCP2_PKT_RETRY) { + hdpktlen = (size_t)nread; + + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + + if (conn->server) { + return NGTCP2_ERR_DISCARD_PKT; + } + + /* Receiving Retry packet after getting Initial packet from server + is invalid. */ + if (conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (conn->client_chosen_version != hd.version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + rv = conn_on_retry(conn, &hd, hdpktlen, pkt, pktlen, ts); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + return NGTCP2_ERR_DISCARD_PKT; + } + return (ngtcp2_ssize)pktlen; + } + + if (pktlen < (size_t)nread + hd.len) { + return NGTCP2_ERR_DISCARD_PKT; + } + + pktlen = (size_t)nread + hd.len; + + if (!ngtcp2_is_supported_version(hd.version)) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (conn->server) { + if (hd.version != conn->client_chosen_version && + (!conn->negotiated_version || hd.version != conn->negotiated_version)) { + return NGTCP2_ERR_DISCARD_PKT; + } + } else if (hd.version != conn->client_chosen_version && + conn->negotiated_version && + hd.version != conn->negotiated_version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + /* Quoted from spec: if subsequent packets of those types include a + different Source Connection ID, they MUST be discarded. */ + if ((conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED) && + !ngtcp2_cid_eq(&conn->dcid.current.cid, &hd.scid)) { + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched SCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + + switch (hd.type) { + case NGTCP2_PKT_0RTT: + if (!conn->server) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (hd.version != conn->client_chosen_version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED) { + if (conn->early.ckm) { + ngtcp2_ssize nread2; + /* TODO Avoid to parse header twice. */ + nread2 = + conn_recv_pkt(conn, path, pi, pkt, pktlen, dgramlen, pkt_ts, ts); + if (nread2 < 0) { + return nread2; + } + } + + /* Discard 0-RTT packet if we don't have a key to decrypt it. */ + return (ngtcp2_ssize)pktlen; + } + + /* Buffer re-ordered 0-RTT packet. */ + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "buffering 0-RTT packet len=%zu", pktlen); + + rv = conn_buffer_pkt(conn, conn->in_pktns, path, pi, pkt, pktlen, dgramlen, + ts); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + return (ngtcp2_ssize)pktlen; + case NGTCP2_PKT_INITIAL: + if (!conn->in_pktns) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_PKT, + "Initial packet is discarded because keys have been discarded"); + return (ngtcp2_ssize)pktlen; + } + + assert(conn->in_pktns); + + if (conn->server) { + if (dgramlen < NGTCP2_MAX_UDP_PAYLOAD_SIZE) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_PKT, + "Initial packet was ignored because it is included in UDP datagram " + "less than %zu bytes: %zu bytes", + NGTCP2_MAX_UDP_PAYLOAD_SIZE, dgramlen); + return NGTCP2_ERR_DISCARD_PKT; + } + if (conn->local.settings.tokenlen) { + rv = verify_token(conn->local.settings.token, + conn->local.settings.tokenlen, &hd); + if (rv != 0) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because token is invalid"); + return NGTCP2_ERR_DISCARD_PKT; + } + } + if ((conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED) == 0) { + /* Set rcid here so that it is available to callback. If this + packet is discarded later in this function and no packet is + processed in this connection attempt so far, connection + will be dropped. */ + conn->rcid = hd.dcid; + + rv = conn_call_recv_client_initial(conn, &hd.dcid); + if (rv != 0) { + return rv; + } + } + } else { + if (hd.tokenlen != 0) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because token is not empty"); + return NGTCP2_ERR_DISCARD_PKT; + } + + if (hd.version != conn->client_chosen_version && + !conn->negotiated_version && conn->vneg.version != hd.version) { + if (!vneg_available_versions_includes(conn->vneg.available_versions, + conn->vneg.available_versionslen, + hd.version)) { + return NGTCP2_ERR_DISCARD_PKT; + } + + /* Install new Initial keys using QUIC version = hd.version */ + rv = conn_call_version_negotiation( + conn, hd.version, + (conn->flags & NGTCP2_CONN_FLAG_RECV_RETRY) + ? &conn->dcid.current.cid + : &conn->rcid); + if (rv != 0) { + return rv; + } + + assert(conn->vneg.version == hd.version); + } + } + + pktns = conn->in_pktns; + crypto = &pktns->crypto.strm; + crypto_level = NGTCP2_CRYPTO_LEVEL_INITIAL; + + if (hd.version == conn->client_chosen_version) { + ckm = pktns->crypto.rx.ckm; + hp_ctx = &pktns->crypto.rx.hp_ctx; + } else { + assert(conn->vneg.version == hd.version); + + ckm = conn->vneg.rx.ckm; + hp_ctx = &conn->vneg.rx.hp_ctx; + } + + break; + case NGTCP2_PKT_HANDSHAKE: + if (hd.version != conn->negotiated_version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (!conn->hs_pktns->crypto.rx.ckm) { + if (conn->server) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_PKT, + "Handshake packet at this point is unexpected and discarded"); + return (ngtcp2_ssize)pktlen; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "buffering Handshake packet len=%zu", pktlen); + + rv = conn_buffer_pkt(conn, conn->hs_pktns, path, pi, pkt, pktlen, + dgramlen, ts); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + return (ngtcp2_ssize)pktlen; + } + + pktns = conn->hs_pktns; + crypto = &pktns->crypto.strm; + crypto_level = NGTCP2_CRYPTO_LEVEL_HANDSHAKE; + ckm = pktns->crypto.rx.ckm; + hp_ctx = &pktns->crypto.rx.hp_ctx; + + break; + default: + /* unknown packet type */ + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of unknown packet type"); + return (ngtcp2_ssize)pktlen; + } + + hp_mask = conn->callbacks.hp_mask; + decrypt = conn->callbacks.decrypt; + aead = &pktns->crypto.ctx.aead; + hp = &pktns->crypto.ctx.hp; + + assert(ckm); + assert(hp_mask); + assert(decrypt); + + rv = conn_ensure_decrypt_hp_buffer(conn, (size_t)nread + 4); + if (rv != 0) { + return rv; + } + + nwrite = decrypt_hp(&hd, conn->crypto.decrypt_hp_buf.base, hp, pkt, pktlen, + (size_t)nread, hp_ctx, hp_mask); + if (nwrite < 0) { + if (ngtcp2_err_is_fatal((int)nwrite)) { + return nwrite; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decrypt packet number"); + return NGTCP2_ERR_DISCARD_PKT; + } + + hdpktlen = (size_t)nwrite; + payload = pkt + hdpktlen; + payloadlen = hd.len - hd.pkt_numlen; + + hd.pkt_num = ngtcp2_pkt_adjust_pkt_num(pktns->rx.max_pkt_num, hd.pkt_num, + pkt_num_bits(hd.pkt_numlen)); + if (hd.pkt_num > NGTCP2_MAX_PKT_NUM) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "pkn=%" PRId64 " is greater than maximum pkn", hd.pkt_num); + return NGTCP2_ERR_DISCARD_PKT; + } + + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + + rv = ngtcp2_pkt_verify_reserved_bits(conn->crypto.decrypt_hp_buf.base[0]); + if (rv != 0) { + invalid_reserved_bits = 1; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet has incorrect reserved bits"); + + /* Will return error after decrypting payload */ + } + + if (pktns_pkt_num_is_duplicate(pktns, hd.pkt_num)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was discarded because of duplicated packet number"); + return NGTCP2_ERR_DISCARD_PKT; + } + + rv = conn_ensure_decrypt_buffer(conn, payloadlen); + if (rv != 0) { + return rv; + } + + nwrite = decrypt_pkt(conn->crypto.decrypt_buf.base, aead, payload, payloadlen, + conn->crypto.decrypt_hp_buf.base, hdpktlen, hd.pkt_num, + ckm, decrypt); + if (nwrite < 0) { + if (ngtcp2_err_is_fatal((int)nwrite)) { + return nwrite; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decrypt packet payload"); + return NGTCP2_ERR_DISCARD_PKT; + } + + if (invalid_reserved_bits) { + return NGTCP2_ERR_PROTO; + } + + if (!conn->server && hd.version != conn->client_chosen_version && + !conn->negotiated_version) { + conn->negotiated_version = hd.version; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "the negotiated version is 0x%08x", + conn->negotiated_version); + } + + payload = conn->crypto.decrypt_buf.base; + payloadlen = (size_t)nwrite; + + switch (hd.type) { + case NGTCP2_PKT_INITIAL: + if (!conn->server || ((conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED) && + !ngtcp2_cid_eq(&conn->rcid, &hd.dcid))) { + rv = conn_verify_dcid(conn, NULL, &hd); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched DCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + } + break; + case NGTCP2_PKT_HANDSHAKE: + rv = conn_verify_dcid(conn, NULL, &hd); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched DCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + break; + default: + ngtcp2_unreachable(); + } + + if (payloadlen == 0) { + /* QUIC packet must contain at least one frame */ + if (hd.type == NGTCP2_PKT_INITIAL) { + return NGTCP2_ERR_DISCARD_PKT; + } + return NGTCP2_ERR_PROTO; + } + + if (hd.type == NGTCP2_PKT_INITIAL && + !(conn->flags & NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED)) { + conn->flags |= NGTCP2_CONN_FLAG_CONN_ID_NEGOTIATED; + if (!conn->server) { + conn->dcid.current.cid = hd.scid; + } + } + + ngtcp2_qlog_pkt_received_start(&conn->qlog); + + for (; payloadlen;) { + nread = ngtcp2_pkt_decode_frame(fr, payload, payloadlen); + if (nread < 0) { + return nread; + } + + payload += nread; + payloadlen -= (size_t)nread; + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + fr->ack.ack_delay = 0; + fr->ack.ack_delay_unscaled = 0; + break; + } + + ngtcp2_log_rx_fr(&conn->log, &hd, fr); + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + if (!conn->server && hd.type == NGTCP2_PKT_HANDSHAKE) { + conn->flags |= NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED; + } + rv = conn_recv_ack(conn, pktns, &fr->ack, pkt_ts, ts); + if (rv != 0) { + return rv; + } + break; + case NGTCP2_FRAME_PADDING: + break; + case NGTCP2_FRAME_CRYPTO: + if (!conn->server && !conn->negotiated_version && + ngtcp2_vec_len(fr->crypto.data, fr->crypto.datacnt)) { + conn->negotiated_version = hd.version; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "the negotiated version is 0x%08x", + conn->negotiated_version); + } + + rv = conn_recv_crypto(conn, crypto_level, crypto, &fr->crypto); + if (rv != 0) { + return rv; + } + require_ack = 1; + break; + case NGTCP2_FRAME_CONNECTION_CLOSE: + rv = conn_recv_connection_close(conn, &fr->connection_close); + if (rv != 0) { + return rv; + } + break; + case NGTCP2_FRAME_PING: + require_ack = 1; + break; + default: + return NGTCP2_ERR_PROTO; + } + + ngtcp2_qlog_write_frame(&conn->qlog, fr); + } + + if (hd.type == NGTCP2_PKT_HANDSHAKE) { + /* Successful processing of Handshake packet from a remote + endpoint validates its source address. */ + conn->dcid.current.flags |= NGTCP2_DCID_FLAG_PATH_VALIDATED; + } + + ngtcp2_qlog_pkt_received_end(&conn->qlog, &hd, pktlen); + + rv = pktns_commit_recv_pkt_num(pktns, hd.pkt_num, require_ack, pkt_ts); + if (rv != 0) { + return rv; + } + + pktns_increase_ecn_counts(pktns, pi); + + /* TODO Initial and Handshake are always acknowledged without + delay. */ + if (require_ack && + (++pktns->acktr.rx_npkt >= conn->local.settings.ack_thresh || + (pi->ecn & NGTCP2_ECN_MASK) == NGTCP2_ECN_CE)) { + ngtcp2_acktr_immediate_ack(&pktns->acktr); + } + + rv = ngtcp2_conn_sched_ack(conn, &pktns->acktr, hd.pkt_num, require_ack, + pkt_ts); + if (rv != 0) { + return rv; + } + + conn_restart_timer_on_read(conn, ts); + + ngtcp2_qlog_metrics_updated(&conn->qlog, &conn->cstat); + + return conn->state == NGTCP2_CS_DRAINING ? NGTCP2_ERR_DRAINING + : (ngtcp2_ssize)pktlen; +} + +static int is_unrecoverable_error(int liberr) { + switch (liberr) { + case NGTCP2_ERR_CRYPTO: + case NGTCP2_ERR_REQUIRED_TRANSPORT_PARAM: + case NGTCP2_ERR_MALFORMED_TRANSPORT_PARAM: + case NGTCP2_ERR_TRANSPORT_PARAM: + case NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE: + return 1; + } + + return 0; +} + +/* + * conn_recv_handshake_cpkt processes compound packet during + * handshake. The buffer pointed by |pkt| might contain multiple + * packets. The 1RTT packet must be the last one because it does not + * have payload length field. + * + * This function returns the same error code returned by + * conn_recv_handshake_pkt. + */ +static ngtcp2_ssize conn_recv_handshake_cpkt(ngtcp2_conn *conn, + const ngtcp2_path *path, + const ngtcp2_pkt_info *pi, + const uint8_t *pkt, size_t pktlen, + ngtcp2_tstamp ts) { + ngtcp2_ssize nread; + size_t dgramlen = pktlen; + const uint8_t *origpkt = pkt; + uint32_t version; + + if (ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + conn->dcid.current.bytes_recv += dgramlen; + } + + while (pktlen) { + nread = + conn_recv_handshake_pkt(conn, path, pi, pkt, pktlen, dgramlen, ts, ts); + if (nread < 0) { + if (ngtcp2_err_is_fatal((int)nread)) { + return nread; + } + + if (nread == NGTCP2_ERR_DRAINING) { + return NGTCP2_ERR_DRAINING; + } + + if ((pkt[0] & NGTCP2_HEADER_FORM_BIT) && pktlen > 4) { + /* Not a Version Negotiation packet */ + ngtcp2_get_uint32(&version, &pkt[1]); + if (ngtcp2_pkt_get_type_long(version, pkt[0]) == NGTCP2_PKT_INITIAL) { + if (conn->server) { + if (is_unrecoverable_error((int)nread)) { + /* If server gets crypto error from TLS stack, it is + unrecoverable, therefore drop connection. */ + return nread; + } + + /* If server discards first Initial, then drop connection + state. This is because SCID in packet might be corrupted + and the current connection state might wrongly discard + valid packet and prevent the handshake from + completing. */ + if (conn->in_pktns && conn->in_pktns->rx.max_pkt_num == -1) { + return NGTCP2_ERR_DROP_CONN; + } + + return (ngtcp2_ssize)dgramlen; + } + /* client */ + if (is_unrecoverable_error((int)nread)) { + /* If client gets crypto error from TLS stack, it is + unrecoverable, therefore drop connection. */ + return nread; + } + return (ngtcp2_ssize)dgramlen; + } + } + + if (nread == NGTCP2_ERR_DISCARD_PKT) { + return (ngtcp2_ssize)dgramlen; + } + + return nread; + } + + if (nread == 0) { + assert(!(pkt[0] & NGTCP2_HEADER_FORM_BIT)); + return pkt - origpkt; + } + + assert(pktlen >= (size_t)nread); + pkt += nread; + pktlen -= (size_t)nread; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "read packet %td left %zu", nread, pktlen); + } + + return (ngtcp2_ssize)dgramlen; +} + +int ngtcp2_conn_init_stream(ngtcp2_conn *conn, ngtcp2_strm *strm, + int64_t stream_id, void *stream_user_data) { + int rv; + uint64_t max_rx_offset; + uint64_t max_tx_offset; + int local_stream = conn_local_stream(conn, stream_id); + + assert(conn->remote.transport_params); + + if (bidi_stream(stream_id)) { + if (local_stream) { + max_rx_offset = + conn->local.transport_params.initial_max_stream_data_bidi_local; + max_tx_offset = + conn->remote.transport_params->initial_max_stream_data_bidi_remote; + } else { + max_rx_offset = + conn->local.transport_params.initial_max_stream_data_bidi_remote; + max_tx_offset = + conn->remote.transport_params->initial_max_stream_data_bidi_local; + } + } else if (local_stream) { + max_rx_offset = 0; + max_tx_offset = conn->remote.transport_params->initial_max_stream_data_uni; + } else { + max_rx_offset = conn->local.transport_params.initial_max_stream_data_uni; + max_tx_offset = 0; + } + + ngtcp2_strm_init(strm, stream_id, NGTCP2_STRM_FLAG_NONE, max_rx_offset, + max_tx_offset, stream_user_data, &conn->frc_objalloc, + conn->mem); + + rv = ngtcp2_map_insert(&conn->strms, (ngtcp2_map_key_type)strm->stream_id, + strm); + if (rv != 0) { + assert(rv != NGTCP2_ERR_INVALID_ARGUMENT); + goto fail; + } + + return 0; + +fail: + ngtcp2_strm_free(strm); + return rv; +} + +/* + * conn_emit_pending_stream_data passes buffered ordered stream data + * to the application. |rx_offset| is the first offset to deliver to + * the application. This function assumes that the data up to + * |rx_offset| has been delivered already. This function only passes + * the ordered data without any gap. If there is a gap, it stops + * providing the data to the application, and returns. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed. + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_emit_pending_stream_data(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t rx_offset) { + size_t datalen; + const uint8_t *data; + int rv; + uint64_t offset; + uint32_t sdflags; + int handshake_completed = conn_is_handshake_completed(conn); + + if (!strm->rx.rob) { + return 0; + } + + for (;;) { + /* Stop calling callback if application has called + ngtcp2_conn_shutdown_stream_read() inside the callback. + Because it doubly counts connection window. */ + if (strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING) { + return 0; + } + + datalen = ngtcp2_rob_data_at(strm->rx.rob, &data, rx_offset); + if (datalen == 0) { + assert(rx_offset == ngtcp2_strm_rx_offset(strm)); + return 0; + } + + offset = rx_offset; + rx_offset += datalen; + + sdflags = NGTCP2_STREAM_DATA_FLAG_NONE; + if ((strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) && + rx_offset == strm->rx.last_offset) { + sdflags |= NGTCP2_STREAM_DATA_FLAG_FIN; + } + if (!handshake_completed) { + sdflags |= NGTCP2_STREAM_DATA_FLAG_EARLY; + } + + rv = conn_call_recv_stream_data(conn, strm, sdflags, offset, data, datalen); + if (rv != 0) { + return rv; + } + + ngtcp2_rob_pop(strm->rx.rob, rx_offset - datalen, datalen); + } +} + +/* + * conn_recv_crypto is called when CRYPTO frame |fr| is received. + * |rx_offset_base| is the offset in the entire TLS handshake stream. + * fr->offset specifies the offset in each encryption level. + * |max_rx_offset| is, if it is nonzero, the maximum offset in the + * entire TLS handshake stream that |fr| can carry. |crypto_level| is + * the encryption level where this data is received. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_PROTO + * CRYPTO frame has invalid offset. + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CRYPTO + * TLS stack reported error. + * NGTCP2_ERR_FRAME_ENCODING + * The end offset exceeds the maximum value. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_recv_crypto(ngtcp2_conn *conn, ngtcp2_crypto_level crypto_level, + ngtcp2_strm *crypto, const ngtcp2_crypto *fr) { + uint64_t fr_end_offset; + uint64_t rx_offset; + int rv; + + if (fr->datacnt == 0) { + return 0; + } + + fr_end_offset = fr->offset + fr->data[0].len; + + if (NGTCP2_MAX_VARINT < fr_end_offset) { + return NGTCP2_ERR_FRAME_ENCODING; + } + + rx_offset = ngtcp2_strm_rx_offset(crypto); + + if (fr_end_offset <= rx_offset) { + if (conn->server && + !(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_EARLY_RETRANSMIT) && + crypto_level == NGTCP2_CRYPTO_LEVEL_INITIAL) { + /* recovery draft: Speeding Up Handshake Completion + + When a server receives an Initial packet containing duplicate + CRYPTO data, it can assume the client did not receive all of + the server's CRYPTO data sent in Initial packets, or the + client's estimated RTT is too small. ... To speed up + handshake completion under these conditions, an endpoint MAY + send a packet containing unacknowledged CRYPTO data earlier + than the PTO expiry, subject to address validation limits; + ... */ + conn->flags |= NGTCP2_CONN_FLAG_HANDSHAKE_EARLY_RETRANSMIT; + conn->in_pktns->rtb.probe_pkt_left = 1; + conn->hs_pktns->rtb.probe_pkt_left = 1; + } + return 0; + } + + crypto->rx.last_offset = ngtcp2_max(crypto->rx.last_offset, fr_end_offset); + + /* TODO Before dispatching incoming data to TLS stack, make sure + that previous data in previous encryption level has been + completely sent to TLS stack. Usually, if data is left, it is an + error because key is generated after consuming all data in the + previous encryption level. */ + if (fr->offset <= rx_offset) { + size_t ncut = (size_t)(rx_offset - fr->offset); + const uint8_t *data = fr->data[0].base + ncut; + size_t datalen = fr->data[0].len - ncut; + uint64_t offset = rx_offset; + + rx_offset += datalen; + rv = ngtcp2_strm_update_rx_offset(crypto, rx_offset); + if (rv != 0) { + return rv; + } + + rv = conn_call_recv_crypto_data(conn, crypto_level, offset, data, datalen); + if (rv != 0) { + return rv; + } + + rv = conn_emit_pending_crypto_data(conn, crypto_level, crypto, rx_offset); + if (rv != 0) { + return rv; + } + + return 0; + } + + if (fr_end_offset - rx_offset > NGTCP2_MAX_REORDERED_CRYPTO_DATA) { + return NGTCP2_ERR_CRYPTO_BUFFER_EXCEEDED; + } + + return ngtcp2_strm_recv_reordering(crypto, fr->data[0].base, fr->data[0].len, + fr->offset); +} + +/* + * conn_max_data_violated returns nonzero if receiving |datalen| + * violates connection flow control on local endpoint. + */ +static int conn_max_data_violated(ngtcp2_conn *conn, uint64_t datalen) { + return conn->rx.max_offset - conn->rx.offset < datalen; +} + +/* + * conn_recv_stream is called when STREAM frame |fr| is received. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_STREAM_STATE + * STREAM frame is received for a local stream which is not + * initiated; or STREAM frame is received for a local + * unidirectional stream + * NGTCP2_ERR_STREAM_LIMIT + * STREAM frame has remote stream ID which is strictly greater + * than the allowed limit. + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_FLOW_CONTROL + * Flow control limit is violated; or the end offset of stream + * data is beyond the NGTCP2_MAX_VARINT. + * NGTCP2_ERR_FINAL_SIZE + * STREAM frame has strictly larger end offset than it is + * permitted. + */ +static int conn_recv_stream(ngtcp2_conn *conn, const ngtcp2_stream *fr) { + int rv; + ngtcp2_strm *strm; + ngtcp2_idtr *idtr; + uint64_t rx_offset, fr_end_offset; + int local_stream; + int bidi; + uint64_t datalen = ngtcp2_vec_len(fr->data, fr->datacnt); + uint32_t sdflags = NGTCP2_STREAM_DATA_FLAG_NONE; + + local_stream = conn_local_stream(conn, fr->stream_id); + bidi = bidi_stream(fr->stream_id); + + if (bidi) { + if (local_stream) { + if (conn->local.bidi.next_stream_id <= fr->stream_id) { + return NGTCP2_ERR_STREAM_STATE; + } + } else if (conn->remote.bidi.max_streams < + ngtcp2_ord_stream_id(fr->stream_id)) { + return NGTCP2_ERR_STREAM_LIMIT; + } + + idtr = &conn->remote.bidi.idtr; + } else { + if (local_stream) { + return NGTCP2_ERR_STREAM_STATE; + } + if (conn->remote.uni.max_streams < ngtcp2_ord_stream_id(fr->stream_id)) { + return NGTCP2_ERR_STREAM_LIMIT; + } + + idtr = &conn->remote.uni.idtr; + } + + if (NGTCP2_MAX_VARINT - datalen < fr->offset) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + strm = ngtcp2_conn_find_stream(conn, fr->stream_id); + if (strm == NULL) { + if (local_stream) { + /* TODO The stream has been closed. This should be responded + with RESET_STREAM, or simply ignored. */ + return 0; + } + + rv = ngtcp2_idtr_open(idtr, fr->stream_id); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + assert(rv == NGTCP2_ERR_STREAM_IN_USE); + /* TODO The stream has been closed. This should be responded + with RESET_STREAM, or simply ignored. */ + return 0; + } + + strm = ngtcp2_objalloc_strm_get(&conn->strm_objalloc); + if (strm == NULL) { + return NGTCP2_ERR_NOMEM; + } + /* TODO Perhaps, call new_stream callback? */ + rv = ngtcp2_conn_init_stream(conn, strm, fr->stream_id, NULL); + if (rv != 0) { + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm); + return rv; + } + + if (!bidi) { + ngtcp2_strm_shutdown(strm, NGTCP2_STRM_FLAG_SHUT_WR); + strm->flags |= NGTCP2_STRM_FLAG_FIN_ACKED; + } + + rv = conn_call_stream_open(conn, strm); + if (rv != 0) { + return rv; + } + } + + fr_end_offset = fr->offset + datalen; + + if (strm->rx.max_offset < fr_end_offset) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + if (strm->rx.last_offset < fr_end_offset) { + uint64_t len = fr_end_offset - strm->rx.last_offset; + + if (conn_max_data_violated(conn, len)) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + conn->rx.offset += len; + + if (strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING) { + ngtcp2_conn_extend_max_offset(conn, len); + } + } + + rx_offset = ngtcp2_strm_rx_offset(strm); + + if (fr->fin) { + if (strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) { + if (strm->rx.last_offset != fr_end_offset) { + return NGTCP2_ERR_FINAL_SIZE; + } + + if (strm->flags & NGTCP2_STRM_FLAG_RECV_RST) { + return 0; + } + + if (rx_offset == fr_end_offset) { + return 0; + } + } else if (strm->rx.last_offset > fr_end_offset) { + return NGTCP2_ERR_FINAL_SIZE; + } else { + strm->rx.last_offset = fr_end_offset; + + ngtcp2_strm_shutdown(strm, NGTCP2_STRM_FLAG_SHUT_RD); + } + } else { + if ((strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) && + strm->rx.last_offset < fr_end_offset) { + return NGTCP2_ERR_FINAL_SIZE; + } + + strm->rx.last_offset = ngtcp2_max(strm->rx.last_offset, fr_end_offset); + + if (fr_end_offset <= rx_offset) { + return 0; + } + + if (strm->flags & NGTCP2_STRM_FLAG_RECV_RST) { + return 0; + } + } + + if (fr->offset <= rx_offset) { + size_t ncut = (size_t)(rx_offset - fr->offset); + uint64_t offset = rx_offset; + const uint8_t *data; + int fin; + + if (fr->datacnt) { + data = fr->data[0].base + ncut; + datalen -= ncut; + + rx_offset += datalen; + rv = ngtcp2_strm_update_rx_offset(strm, rx_offset); + if (rv != 0) { + return rv; + } + } else { + data = NULL; + datalen = 0; + } + + if (strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING) { + return ngtcp2_conn_close_stream_if_shut_rdwr(conn, strm); + } + + fin = (strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) && + rx_offset == strm->rx.last_offset; + + if (fin || datalen) { + if (fin) { + sdflags |= NGTCP2_STREAM_DATA_FLAG_FIN; + } + if (!conn_is_handshake_completed(conn)) { + sdflags |= NGTCP2_STREAM_DATA_FLAG_EARLY; + } + rv = conn_call_recv_stream_data(conn, strm, sdflags, offset, data, + (size_t)datalen); + if (rv != 0) { + return rv; + } + + rv = conn_emit_pending_stream_data(conn, strm, rx_offset); + if (rv != 0) { + return rv; + } + } + } else if (fr->datacnt) { + rv = ngtcp2_strm_recv_reordering(strm, fr->data[0].base, fr->data[0].len, + fr->offset); + if (rv != 0) { + return rv; + } + } + return ngtcp2_conn_close_stream_if_shut_rdwr(conn, strm); +} + +/* + * conn_reset_stream adds RESET_STREAM frame to the transmission + * queue. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_reset_stream(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t app_error_code) { + int rv; + ngtcp2_frame_chain *frc; + ngtcp2_pktns *pktns = &conn->pktns; + + rv = ngtcp2_frame_chain_objalloc_new(&frc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + frc->fr.type = NGTCP2_FRAME_RESET_STREAM; + frc->fr.reset_stream.stream_id = strm->stream_id; + frc->fr.reset_stream.app_error_code = app_error_code; + frc->fr.reset_stream.final_size = strm->tx.offset; + + /* TODO This prepends RESET_STREAM to pktns->tx.frq. */ + frc->next = pktns->tx.frq; + pktns->tx.frq = frc; + + return 0; +} + +/* + * conn_stop_sending adds STOP_SENDING frame to the transmission + * queue. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_stop_sending(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t app_error_code) { + int rv; + ngtcp2_frame_chain *frc; + ngtcp2_pktns *pktns = &conn->pktns; + + rv = ngtcp2_frame_chain_objalloc_new(&frc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + frc->fr.type = NGTCP2_FRAME_STOP_SENDING; + frc->fr.stop_sending.stream_id = strm->stream_id; + frc->fr.stop_sending.app_error_code = app_error_code; + + /* TODO This prepends STOP_SENDING to pktns->tx.frq. */ + frc->next = pktns->tx.frq; + pktns->tx.frq = frc; + + return 0; +} + +/* + * handle_max_remote_streams_extension extends + * |*punsent_max_remote_streams| by |n| if a condition allows it. + */ +static void +handle_max_remote_streams_extension(uint64_t *punsent_max_remote_streams, + size_t n) { + if ( +#if SIZE_MAX > UINT32_MAX + NGTCP2_MAX_STREAMS < n || +#endif /* SIZE_MAX > UINT32_MAX */ + *punsent_max_remote_streams > (uint64_t)(NGTCP2_MAX_STREAMS - n)) { + *punsent_max_remote_streams = NGTCP2_MAX_STREAMS; + } else { + *punsent_max_remote_streams += n; + } +} + +/* + * conn_recv_reset_stream is called when RESET_STREAM |fr| is + * received. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_STREAM_STATE + * RESET_STREAM frame is received to the local stream which is not + * initiated. + * NGTCP2_ERR_STREAM_LIMIT + * RESET_STREAM frame has remote stream ID which is strictly + * greater than the allowed limit. + * NGTCP2_ERR_PROTO + * RESET_STREAM frame is received to the local unidirectional + * stream + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_FLOW_CONTROL + * Flow control limit is violated; or the final size is beyond the + * NGTCP2_MAX_VARINT. + * NGTCP2_ERR_FINAL_SIZE + * The final offset is strictly larger than it is permitted. + */ +static int conn_recv_reset_stream(ngtcp2_conn *conn, + const ngtcp2_reset_stream *fr) { + ngtcp2_strm *strm; + int local_stream = conn_local_stream(conn, fr->stream_id); + int bidi = bidi_stream(fr->stream_id); + uint64_t datalen; + ngtcp2_idtr *idtr; + int rv; + + /* TODO share this piece of code */ + if (bidi) { + if (local_stream) { + if (conn->local.bidi.next_stream_id <= fr->stream_id) { + return NGTCP2_ERR_STREAM_STATE; + } + } else if (conn->remote.bidi.max_streams < + ngtcp2_ord_stream_id(fr->stream_id)) { + return NGTCP2_ERR_STREAM_LIMIT; + } + + idtr = &conn->remote.bidi.idtr; + } else { + if (local_stream) { + return NGTCP2_ERR_PROTO; + } + if (conn->remote.uni.max_streams < ngtcp2_ord_stream_id(fr->stream_id)) { + return NGTCP2_ERR_STREAM_LIMIT; + } + + idtr = &conn->remote.uni.idtr; + } + + if (NGTCP2_MAX_VARINT < fr->final_size) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + strm = ngtcp2_conn_find_stream(conn, fr->stream_id); + if (strm == NULL) { + if (local_stream) { + return 0; + } + + rv = ngtcp2_idtr_open(idtr, fr->stream_id); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + assert(rv == NGTCP2_ERR_STREAM_IN_USE); + return 0; + } + + if (conn_initial_stream_rx_offset(conn, fr->stream_id) < fr->final_size || + conn_max_data_violated(conn, fr->final_size)) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + /* Stream is reset before we create ngtcp2_strm object. */ + conn->rx.offset += fr->final_size; + ngtcp2_conn_extend_max_offset(conn, fr->final_size); + + rv = conn_call_stream_reset(conn, fr->stream_id, fr->final_size, + fr->app_error_code, NULL); + if (rv != 0) { + return rv; + } + + /* There will be no activity in this stream because we got + RESET_STREAM and don't write stream data any further. This + effectively allows another new stream for peer. */ + if (bidi) { + handle_max_remote_streams_extension(&conn->remote.bidi.unsent_max_streams, + 1); + } else { + handle_max_remote_streams_extension(&conn->remote.uni.unsent_max_streams, + 1); + } + + return 0; + } + + if ((strm->flags & NGTCP2_STRM_FLAG_SHUT_RD)) { + if (strm->rx.last_offset != fr->final_size) { + return NGTCP2_ERR_FINAL_SIZE; + } + } else if (strm->rx.last_offset > fr->final_size) { + return NGTCP2_ERR_FINAL_SIZE; + } + + if (strm->flags & NGTCP2_STRM_FLAG_RECV_RST) { + return 0; + } + + if (strm->rx.max_offset < fr->final_size) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + datalen = fr->final_size - strm->rx.last_offset; + + if (conn_max_data_violated(conn, datalen)) { + return NGTCP2_ERR_FLOW_CONTROL; + } + + rv = conn_call_stream_reset(conn, fr->stream_id, fr->final_size, + fr->app_error_code, strm->stream_user_data); + if (rv != 0) { + return rv; + } + + /* Extend connection flow control window for the amount of data + which are not passed to application. */ + if (!(strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING)) { + ngtcp2_conn_extend_max_offset(conn, strm->rx.last_offset - + ngtcp2_strm_rx_offset(strm)); + } + + conn->rx.offset += datalen; + ngtcp2_conn_extend_max_offset(conn, datalen); + + strm->rx.last_offset = fr->final_size; + strm->flags |= NGTCP2_STRM_FLAG_SHUT_RD | NGTCP2_STRM_FLAG_RECV_RST; + + ngtcp2_strm_set_app_error_code(strm, fr->app_error_code); + + return ngtcp2_conn_close_stream_if_shut_rdwr(conn, strm); +} + +/* + * conn_recv_stop_sending is called when STOP_SENDING |fr| is received. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_STREAM_STATE + * STOP_SENDING frame is received for a local stream which is not + * initiated; or STOP_SENDING frame is received for a local + * unidirectional stream. + * NGTCP2_ERR_STREAM_LIMIT + * STOP_SENDING frame has remote stream ID which is strictly + * greater than the allowed limit. + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_recv_stop_sending(ngtcp2_conn *conn, + const ngtcp2_stop_sending *fr) { + int rv; + ngtcp2_strm *strm; + ngtcp2_idtr *idtr; + int local_stream = conn_local_stream(conn, fr->stream_id); + int bidi = bidi_stream(fr->stream_id); + + if (bidi) { + if (local_stream) { + if (conn->local.bidi.next_stream_id <= fr->stream_id) { + return NGTCP2_ERR_STREAM_STATE; + } + } else if (conn->remote.bidi.max_streams < + ngtcp2_ord_stream_id(fr->stream_id)) { + return NGTCP2_ERR_STREAM_LIMIT; + } + + idtr = &conn->remote.bidi.idtr; + } else { + if (!local_stream || conn->local.uni.next_stream_id <= fr->stream_id) { + return NGTCP2_ERR_STREAM_STATE; + } + + idtr = &conn->remote.uni.idtr; + } + + strm = ngtcp2_conn_find_stream(conn, fr->stream_id); + if (strm == NULL) { + if (local_stream) { + return 0; + } + rv = ngtcp2_idtr_open(idtr, fr->stream_id); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + assert(rv == NGTCP2_ERR_STREAM_IN_USE); + return 0; + } + + /* Frame is received reset before we create ngtcp2_strm + object. */ + strm = ngtcp2_objalloc_strm_get(&conn->strm_objalloc); + if (strm == NULL) { + return NGTCP2_ERR_NOMEM; + } + rv = ngtcp2_conn_init_stream(conn, strm, fr->stream_id, NULL); + if (rv != 0) { + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm); + return rv; + } + + rv = conn_call_stream_open(conn, strm); + if (rv != 0) { + return rv; + } + } + + ngtcp2_strm_set_app_error_code(strm, fr->app_error_code); + + /* No RESET_STREAM is required if we have sent FIN and all data have + been acknowledged. */ + if (!ngtcp2_strm_is_all_tx_data_fin_acked(strm) && + !(strm->flags & NGTCP2_STRM_FLAG_SENT_RST)) { + rv = conn_reset_stream(conn, strm, fr->app_error_code); + if (rv != 0) { + return rv; + } + } + + strm->flags |= NGTCP2_STRM_FLAG_SHUT_WR | NGTCP2_STRM_FLAG_SENT_RST; + + if (ngtcp2_strm_is_tx_queued(strm) && !ngtcp2_strm_streamfrq_empty(strm)) { + assert(conn->tx.strmq_nretrans); + --conn->tx.strmq_nretrans; + } + + ngtcp2_strm_streamfrq_clear(strm); + + return ngtcp2_conn_close_stream_if_shut_rdwr(conn, strm); +} + +/* + * check_stateless_reset returns nonzero if Stateless Reset |sr| + * coming via |path| is valid against |dcid|. + */ +static int check_stateless_reset(const ngtcp2_dcid *dcid, + const ngtcp2_path *path, + const ngtcp2_pkt_stateless_reset *sr) { + return ngtcp2_path_eq(&dcid->ps.path, path) && + ngtcp2_dcid_verify_stateless_reset_token( + dcid, sr->stateless_reset_token) == 0; +} + +/* + * conn_on_stateless_reset decodes Stateless Reset from the buffer + * pointed by |payload| whose length is |payloadlen|. |payload| + * should start after first byte of packet. + * + * If Stateless Reset is decoded, and the Stateless Reset Token is + * validated, the connection is closed. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_INVALID_ARGUMENT + * Could not decode Stateless Reset; or Stateless Reset Token does + * not match; or No stateless reset token is available. + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed. + */ +static int conn_on_stateless_reset(ngtcp2_conn *conn, const ngtcp2_path *path, + const uint8_t *payload, size_t payloadlen) { + int rv = 1; + ngtcp2_pv *pv = conn->pv; + ngtcp2_dcid *dcid; + ngtcp2_pkt_stateless_reset sr; + size_t len, i; + + rv = ngtcp2_pkt_decode_stateless_reset(&sr, payload, payloadlen); + if (rv != 0) { + return rv; + } + + if (!check_stateless_reset(&conn->dcid.current, path, &sr) && + (!pv || (!check_stateless_reset(&pv->dcid, path, &sr) && + (!(pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) || + !check_stateless_reset(&pv->fallback_dcid, path, &sr))))) { + len = ngtcp2_ringbuf_len(&conn->dcid.retired.rb); + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.retired.rb, i); + if (check_stateless_reset(dcid, path, &sr)) { + break; + } + } + + if (i == len) { + len = ngtcp2_ringbuf_len(&conn->dcid.bound.rb); + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, i); + if (check_stateless_reset(dcid, path, &sr)) { + break; + } + } + + if (i == len) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + } + } + + conn->state = NGTCP2_CS_DRAINING; + + ngtcp2_log_rx_sr(&conn->log, &sr); + + ngtcp2_qlog_stateless_reset_pkt_received(&conn->qlog, &sr); + + return conn_call_recv_stateless_reset(conn, &sr); +} + +/* + * conn_recv_max_streams processes the incoming MAX_STREAMS frame + * |fr|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed. + * NGTCP2_ERR_FRAME_ENCODING + * The maximum streams field exceeds the maximum value. + */ +static int conn_recv_max_streams(ngtcp2_conn *conn, + const ngtcp2_max_streams *fr) { + uint64_t n; + + if (fr->max_streams > NGTCP2_MAX_STREAMS) { + return NGTCP2_ERR_FRAME_ENCODING; + } + + n = ngtcp2_min(fr->max_streams, NGTCP2_MAX_STREAMS); + + if (fr->type == NGTCP2_FRAME_MAX_STREAMS_BIDI) { + if (conn->local.bidi.max_streams < n) { + conn->local.bidi.max_streams = n; + return conn_call_extend_max_local_streams_bidi(conn, n); + } + return 0; + } + + if (conn->local.uni.max_streams < n) { + conn->local.uni.max_streams = n; + return conn_call_extend_max_local_streams_uni(conn, n); + } + return 0; +} + +static int conn_retire_dcid_prior_to(ngtcp2_conn *conn, ngtcp2_ringbuf *rb, + uint64_t retire_prior_to) { + size_t i; + ngtcp2_dcid *dcid, *last; + int rv; + + for (i = 0; i < ngtcp2_ringbuf_len(rb);) { + dcid = ngtcp2_ringbuf_get(rb, i); + if (dcid->seq >= retire_prior_to) { + ++i; + continue; + } + + rv = conn_retire_dcid_seq(conn, dcid->seq); + if (rv != 0) { + return rv; + } + + if (i == 0) { + ngtcp2_ringbuf_pop_front(rb); + continue; + } + + if (i == ngtcp2_ringbuf_len(rb) - 1) { + ngtcp2_ringbuf_pop_back(rb); + break; + } + + last = ngtcp2_ringbuf_get(rb, ngtcp2_ringbuf_len(rb) - 1); + ngtcp2_dcid_copy(dcid, last); + ngtcp2_ringbuf_pop_back(rb); + } + + return 0; +} + +/* + * conn_recv_new_connection_id processes the incoming + * NEW_CONNECTION_ID frame |fr|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_PROTO + * |fr| has the duplicated sequence number with different CID or + * token; or DCID is zero-length. + */ +static int conn_recv_new_connection_id(ngtcp2_conn *conn, + const ngtcp2_new_connection_id *fr) { + size_t i, len; + ngtcp2_dcid *dcid; + ngtcp2_pv *pv = conn->pv; + int rv; + int found = 0; + size_t extra_dcid = 0; + + if (conn->dcid.current.cid.datalen == 0) { + return NGTCP2_ERR_PROTO; + } + + if (fr->retire_prior_to > fr->seq) { + return NGTCP2_ERR_FRAME_ENCODING; + } + + rv = ngtcp2_dcid_verify_uniqueness(&conn->dcid.current, fr->seq, &fr->cid, + fr->stateless_reset_token); + if (rv != 0) { + return rv; + } + if (ngtcp2_cid_eq(&conn->dcid.current.cid, &fr->cid)) { + found = 1; + } + + if (pv) { + rv = ngtcp2_dcid_verify_uniqueness(&pv->dcid, fr->seq, &fr->cid, + fr->stateless_reset_token); + if (rv != 0) { + return rv; + } + if (ngtcp2_cid_eq(&pv->dcid.cid, &fr->cid)) { + found = 1; + } + } + + len = ngtcp2_ringbuf_len(&conn->dcid.bound.rb); + + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, i); + rv = ngtcp2_dcid_verify_uniqueness(dcid, fr->seq, &fr->cid, + fr->stateless_reset_token); + if (rv != 0) { + return NGTCP2_ERR_PROTO; + } + if (ngtcp2_cid_eq(&dcid->cid, &fr->cid)) { + found = 1; + } + } + + len = ngtcp2_ringbuf_len(&conn->dcid.unused.rb); + + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, i); + rv = ngtcp2_dcid_verify_uniqueness(dcid, fr->seq, &fr->cid, + fr->stateless_reset_token); + if (rv != 0) { + return NGTCP2_ERR_PROTO; + } + if (ngtcp2_cid_eq(&dcid->cid, &fr->cid)) { + found = 1; + } + } + + if (conn->dcid.retire_prior_to < fr->retire_prior_to) { + conn->dcid.retire_prior_to = fr->retire_prior_to; + + rv = conn_retire_dcid_prior_to(conn, &conn->dcid.bound.rb, + fr->retire_prior_to); + if (rv != 0) { + return rv; + } + + rv = conn_retire_dcid_prior_to(conn, &conn->dcid.unused.rb, + conn->dcid.retire_prior_to); + if (rv != 0) { + return rv; + } + } else if (fr->seq < conn->dcid.retire_prior_to) { + /* If packets are reordered, we might have retire_prior_to which + is larger than fr->seq. + + A malicious peer might send crafted NEW_CONNECTION_ID to force + local endpoint to create lots of RETIRE_CONNECTION_ID frames. + For example, a peer might send seq = 50000 and retire_prior_to + = 50000. Then send NEW_CONNECTION_ID frames with seq < + 50000. */ + return conn_retire_dcid_seq(conn, fr->seq); + } + + if (found) { + return 0; + } + + if (ngtcp2_gaptr_is_pushed(&conn->dcid.seqgap, fr->seq, 1)) { + return 0; + } + + rv = ngtcp2_gaptr_push(&conn->dcid.seqgap, fr->seq, 1); + if (rv != 0) { + return rv; + } + + if (ngtcp2_ksl_len(&conn->dcid.seqgap.gap) > 32) { + ngtcp2_gaptr_drop_first_gap(&conn->dcid.seqgap); + } + + len = ngtcp2_ringbuf_len(&conn->dcid.unused.rb); + + if (conn->dcid.current.seq >= conn->dcid.retire_prior_to) { + ++extra_dcid; + } + if (pv) { + if (pv->dcid.seq != conn->dcid.current.seq && + pv->dcid.seq >= conn->dcid.retire_prior_to) { + ++extra_dcid; + } + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + pv->fallback_dcid.seq != conn->dcid.current.seq && + pv->fallback_dcid.seq >= conn->dcid.retire_prior_to) { + ++extra_dcid; + } + } + + if (conn->local.transport_params.active_connection_id_limit <= + len + extra_dcid) { + return NGTCP2_ERR_CONNECTION_ID_LIMIT; + } + + if (len >= NGTCP2_MAX_DCID_POOL_SIZE) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, "too many connection ID"); + return 0; + } + + dcid = ngtcp2_ringbuf_push_back(&conn->dcid.unused.rb); + ngtcp2_dcid_init(dcid, fr->seq, &fr->cid, fr->stateless_reset_token); + + return 0; +} + +/* + * conn_post_process_recv_new_connection_id handles retirement request + * of active DCIDs. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_post_process_recv_new_connection_id(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + ngtcp2_pv *pv = conn->pv; + ngtcp2_dcid *dcid; + int rv; + + if (conn->dcid.current.seq < conn->dcid.retire_prior_to) { + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb) == 0) { + return 0; + } + + rv = conn_retire_dcid(conn, &conn->dcid.current, ts); + if (rv != 0) { + return rv; + } + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + if (pv) { + if (conn->dcid.current.seq == pv->dcid.seq) { + ngtcp2_dcid_copy_cid_token(&pv->dcid, dcid); + } + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + conn->dcid.current.seq == pv->fallback_dcid.seq) { + ngtcp2_dcid_copy_cid_token(&pv->fallback_dcid, dcid); + } + } + + ngtcp2_dcid_copy_cid_token(&conn->dcid.current, dcid); + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + + rv = conn_call_activate_dcid(conn, &conn->dcid.current); + if (rv != 0) { + return rv; + } + } + + if (pv) { + if (pv->dcid.seq < conn->dcid.retire_prior_to) { + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb)) { + rv = conn_retire_dcid(conn, &pv->dcid, ts); + if (rv != 0) { + return rv; + } + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + pv->dcid.seq == pv->fallback_dcid.seq) { + ngtcp2_dcid_copy_cid_token(&pv->fallback_dcid, dcid); + } + + ngtcp2_dcid_copy_cid_token(&pv->dcid, dcid); + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + + rv = conn_call_activate_dcid(conn, &pv->dcid); + if (rv != 0) { + return rv; + } + } else { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PTV, + "path migration is aborted because connection ID is" + "retired and no unused connection ID is available"); + + return conn_abort_pv(conn, ts); + } + } + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + pv->fallback_dcid.seq < conn->dcid.retire_prior_to) { + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb)) { + rv = conn_retire_dcid(conn, &pv->fallback_dcid, ts); + if (rv != 0) { + return rv; + } + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + ngtcp2_dcid_copy_cid_token(&pv->fallback_dcid, dcid); + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + + rv = conn_call_activate_dcid(conn, &pv->fallback_dcid); + if (rv != 0) { + return rv; + } + } else { + /* Now we have no fallback dcid. */ + return conn_abort_pv(conn, ts); + } + } + } + + return 0; +} + +/* + * conn_recv_retire_connection_id processes the incoming + * RETIRE_CONNECTION_ID frame |fr|. |hd| is a packet header which + * |fr| is included. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_PROTO + * SCID is zero-length. + * NGTCP2_ERR_FRAME_ENCODING + * Attempt to retire CID which is used as DCID to send this frame. + */ +static int conn_recv_retire_connection_id(ngtcp2_conn *conn, + const ngtcp2_pkt_hd *hd, + const ngtcp2_retire_connection_id *fr, + ngtcp2_tstamp ts) { + ngtcp2_ksl_it it; + ngtcp2_scid *scid; + + if (conn->oscid.datalen == 0 || conn->scid.last_seq < fr->seq) { + return NGTCP2_ERR_PROTO; + } + + for (it = ngtcp2_ksl_begin(&conn->scid.set); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + scid = ngtcp2_ksl_it_get(&it); + if (scid->seq == fr->seq) { + if (ngtcp2_cid_eq(&scid->cid, &hd->dcid)) { + return NGTCP2_ERR_PROTO; + } + + if (!(scid->flags & NGTCP2_SCID_FLAG_RETIRED)) { + scid->flags |= NGTCP2_SCID_FLAG_RETIRED; + ++conn->scid.num_retired; + } + + if (scid->pe.index != NGTCP2_PQ_BAD_INDEX) { + ngtcp2_pq_remove(&conn->scid.used, &scid->pe); + scid->pe.index = NGTCP2_PQ_BAD_INDEX; + } + + scid->retired_ts = ts; + + return ngtcp2_pq_push(&conn->scid.used, &scid->pe); + } + } + + return 0; +} + +/* + * conn_recv_new_token processes the incoming NEW_TOKEN frame |fr|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_FRAME_ENCODING + * Token is empty + * NGTCP2_ERR_PROTO: + * Server received NEW_TOKEN. + */ +static int conn_recv_new_token(ngtcp2_conn *conn, const ngtcp2_new_token *fr) { + if (conn->server) { + return NGTCP2_ERR_PROTO; + } + + if (fr->tokenlen == 0) { + return NGTCP2_ERR_FRAME_ENCODING; + } + + return conn_call_recv_new_token(conn, fr->token, fr->tokenlen); +} + +/* + * conn_recv_streams_blocked_bidi processes the incoming + * STREAMS_BLOCKED (0x16). + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_FRAME_ENCODING + * Maximum Streams is larger than advertised value. + */ +static int conn_recv_streams_blocked_bidi(ngtcp2_conn *conn, + ngtcp2_streams_blocked *fr) { + if (fr->max_streams > conn->remote.bidi.max_streams) { + return NGTCP2_ERR_FRAME_ENCODING; + } + + return 0; +} + +/* + * conn_recv_streams_blocked_uni processes the incoming + * STREAMS_BLOCKED (0x17). + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_FRAME_ENCODING + * Maximum Streams is larger than advertised value. + */ +static int conn_recv_streams_blocked_uni(ngtcp2_conn *conn, + ngtcp2_streams_blocked *fr) { + if (fr->max_streams > conn->remote.uni.max_streams) { + return NGTCP2_ERR_FRAME_ENCODING; + } + + return 0; +} + +/* + * conn_select_preferred_addr asks a client application to select a + * server address from preferred addresses received from server. If a + * client chooses the address, path validation will start. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_select_preferred_addr(ngtcp2_conn *conn) { + ngtcp2_path_storage ps; + int rv; + ngtcp2_duration pto, initial_pto, timeout; + ngtcp2_pv *pv; + ngtcp2_dcid *dcid; + + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb) == 0) { + return 0; + } + + ngtcp2_path_storage_zero(&ps); + ngtcp2_addr_copy(&ps.path.local, &conn->dcid.current.ps.path.local); + + rv = conn_call_select_preferred_addr(conn, &ps.path); + if (rv != 0) { + return rv; + } + + if (ps.path.remote.addrlen == 0 || + ngtcp2_addr_eq(&conn->dcid.current.ps.path.remote, &ps.path.remote)) { + return 0; + } + + assert(conn->pv == NULL); + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + ngtcp2_dcid_set_path(dcid, &ps.path); + + pto = conn_compute_pto(conn, &conn->pktns); + initial_pto = conn_compute_initial_pto(conn, &conn->pktns); + timeout = 3 * ngtcp2_max(pto, initial_pto); + + rv = ngtcp2_pv_new(&pv, dcid, timeout, NGTCP2_PV_FLAG_PREFERRED_ADDR, + &conn->log, conn->mem); + if (rv != 0) { + /* TODO Call ngtcp2_dcid_free here if it is introduced */ + return rv; + } + + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + conn->pv = pv; + + return conn_call_activate_dcid(conn, &pv->dcid); +} + +/* + * conn_recv_handshake_done processes the incoming HANDSHAKE_DONE + * frame |fr|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_PROTO + * Server received HANDSHAKE_DONE frame. + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_recv_handshake_done(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + int rv; + + if (conn->server) { + return NGTCP2_ERR_PROTO; + } + + if (conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED) { + return 0; + } + + conn->flags |= NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED | + NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED; + + conn->pktns.rtb.persistent_congestion_start_ts = ts; + + conn_discard_handshake_state(conn, ts); + + assert(conn->remote.transport_params); + + if (conn->remote.transport_params->preferred_address_present) { + rv = conn_select_preferred_addr(conn); + if (rv != 0) { + return rv; + } + } + + rv = conn_call_handshake_confirmed(conn); + if (rv != 0) { + return rv; + } + + /* Re-arm loss detection timer after handshake has been + confirmed. */ + ngtcp2_conn_set_loss_detection_timer(conn, ts); + + return 0; +} + +/* + * conn_recv_datagram processes the incoming DATAGRAM frame |fr|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + */ +static int conn_recv_datagram(ngtcp2_conn *conn, ngtcp2_datagram *fr) { + assert(conn->local.transport_params.max_datagram_frame_size); + + return conn_call_recv_datagram(conn, fr); +} + +/* + * conn_key_phase_changed returns nonzero if |hd| indicates that the + * key phase has unexpected value. + */ +static int conn_key_phase_changed(ngtcp2_conn *conn, const ngtcp2_pkt_hd *hd) { + ngtcp2_pktns *pktns = &conn->pktns; + + return !(pktns->crypto.rx.ckm->flags & NGTCP2_CRYPTO_KM_FLAG_KEY_PHASE_ONE) ^ + !(hd->flags & NGTCP2_PKT_FLAG_KEY_PHASE); +} + +/* + * conn_prepare_key_update installs new updated keys. + */ +static int conn_prepare_key_update(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + int rv; + ngtcp2_tstamp confirmed_ts = conn->crypto.key_update.confirmed_ts; + ngtcp2_duration pto = conn_compute_pto(conn, &conn->pktns); + ngtcp2_pktns *pktns = &conn->pktns; + ngtcp2_crypto_km *rx_ckm = pktns->crypto.rx.ckm; + ngtcp2_crypto_km *tx_ckm = pktns->crypto.tx.ckm; + ngtcp2_crypto_km *new_rx_ckm, *new_tx_ckm; + ngtcp2_crypto_aead_ctx rx_aead_ctx = {0}, tx_aead_ctx = {0}; + size_t secretlen, ivlen; + + if ((conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED) && + tx_ckm->use_count >= pktns->crypto.ctx.max_encryption && + ngtcp2_conn_initiate_key_update(conn, ts) != 0) { + return NGTCP2_ERR_AEAD_LIMIT_REACHED; + } + + if ((conn->flags & NGTCP2_CONN_FLAG_KEY_UPDATE_NOT_CONFIRMED) || + (confirmed_ts != UINT64_MAX && confirmed_ts + pto > ts)) { + return 0; + } + + if (conn->crypto.key_update.new_rx_ckm || + conn->crypto.key_update.new_tx_ckm) { + assert(conn->crypto.key_update.new_rx_ckm); + assert(conn->crypto.key_update.new_tx_ckm); + return 0; + } + + secretlen = rx_ckm->secret.len; + ivlen = rx_ckm->iv.len; + + rv = ngtcp2_crypto_km_nocopy_new(&conn->crypto.key_update.new_rx_ckm, + secretlen, ivlen, conn->mem); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_crypto_km_nocopy_new(&conn->crypto.key_update.new_tx_ckm, + secretlen, ivlen, conn->mem); + if (rv != 0) { + return rv; + } + + new_rx_ckm = conn->crypto.key_update.new_rx_ckm; + new_tx_ckm = conn->crypto.key_update.new_tx_ckm; + + rv = conn_call_update_key( + conn, new_rx_ckm->secret.base, new_tx_ckm->secret.base, &rx_aead_ctx, + new_rx_ckm->iv.base, &tx_aead_ctx, new_tx_ckm->iv.base, + rx_ckm->secret.base, tx_ckm->secret.base, secretlen); + if (rv != 0) { + return rv; + } + + new_rx_ckm->aead_ctx = rx_aead_ctx; + new_tx_ckm->aead_ctx = tx_aead_ctx; + + if (!(rx_ckm->flags & NGTCP2_CRYPTO_KM_FLAG_KEY_PHASE_ONE)) { + new_rx_ckm->flags |= NGTCP2_CRYPTO_KM_FLAG_KEY_PHASE_ONE; + new_tx_ckm->flags |= NGTCP2_CRYPTO_KM_FLAG_KEY_PHASE_ONE; + } + + if (conn->crypto.key_update.old_rx_ckm) { + conn_call_delete_crypto_aead_ctx( + conn, &conn->crypto.key_update.old_rx_ckm->aead_ctx); + ngtcp2_crypto_km_del(conn->crypto.key_update.old_rx_ckm, conn->mem); + conn->crypto.key_update.old_rx_ckm = NULL; + } + + return 0; +} + +/* + * conn_rotate_keys rotates keys. The current key moves to old key, + * and new key moves to the current key. If the local endpoint + * initiated this key update, pass nonzero as |initiator|. + */ +static void conn_rotate_keys(ngtcp2_conn *conn, int64_t pkt_num, + int initiator) { + ngtcp2_pktns *pktns = &conn->pktns; + + assert(conn->crypto.key_update.new_rx_ckm); + assert(conn->crypto.key_update.new_tx_ckm); + assert(!conn->crypto.key_update.old_rx_ckm); + assert(!(conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING)); + + conn->crypto.key_update.old_rx_ckm = pktns->crypto.rx.ckm; + + pktns->crypto.rx.ckm = conn->crypto.key_update.new_rx_ckm; + conn->crypto.key_update.new_rx_ckm = NULL; + pktns->crypto.rx.ckm->pkt_num = pkt_num; + + assert(pktns->crypto.tx.ckm); + + conn_call_delete_crypto_aead_ctx(conn, &pktns->crypto.tx.ckm->aead_ctx); + ngtcp2_crypto_km_del(pktns->crypto.tx.ckm, conn->mem); + + pktns->crypto.tx.ckm = conn->crypto.key_update.new_tx_ckm; + conn->crypto.key_update.new_tx_ckm = NULL; + pktns->crypto.tx.ckm->pkt_num = pktns->tx.last_pkt_num + 1; + + conn->flags |= NGTCP2_CONN_FLAG_KEY_UPDATE_NOT_CONFIRMED; + if (initiator) { + conn->flags |= NGTCP2_CONN_FLAG_KEY_UPDATE_INITIATOR; + } +} + +/* + * conn_path_validation_in_progress returns nonzero if path validation + * against |path| is underway. + */ +static int conn_path_validation_in_progress(ngtcp2_conn *conn, + const ngtcp2_path *path) { + ngtcp2_pv *pv = conn->pv; + + return pv && ngtcp2_path_eq(&pv->dcid.ps.path, path); +} + +/* + * conn_recv_non_probing_pkt_on_new_path is called when non-probing + * packet is received via new path. It starts path validation against + * the new path. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CONN_ID_BLOCKED + * No DCID is available + * NGTCP2_ERR_NOMEM + * Out of memory + */ +static int conn_recv_non_probing_pkt_on_new_path(ngtcp2_conn *conn, + const ngtcp2_path *path, + size_t dgramlen, + int new_cid_used, + ngtcp2_tstamp ts) { + + ngtcp2_dcid dcid, *bound_dcid, *last; + ngtcp2_pv *pv; + int rv; + ngtcp2_duration pto, initial_pto, timeout; + int require_new_cid; + int local_addr_eq; + uint32_t remote_addr_cmp; + size_t len, i; + + assert(conn->server); + + if (conn->pv && (conn->pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + ngtcp2_path_eq(&conn->pv->fallback_dcid.ps.path, path)) { + /* If new path equals fallback path, that means connection + migrated back to the original path. Fallback path is + considered to be validated. */ + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PTV, + "path is migrated back to the original path"); + ngtcp2_dcid_copy(&conn->dcid.current, &conn->pv->fallback_dcid); + conn_reset_congestion_state(conn, ts); + conn->dcid.current.bytes_recv += dgramlen; + conn_reset_ecn_validation_state(conn); + + rv = conn_abort_pv(conn, ts); + if (rv != 0) { + return rv; + } + + /* Run PMTUD just in case if it is prematurely aborted */ + assert(!conn->pmtud); + + return conn_start_pmtud(conn); + } + + remote_addr_cmp = + ngtcp2_addr_compare(&conn->dcid.current.ps.path.remote, &path->remote); + local_addr_eq = + ngtcp2_addr_eq(&conn->dcid.current.ps.path.local, &path->local); + + /* + * When to change DCID? RFC 9002 section 9.5 says: + * + * An endpoint MUST NOT reuse a connection ID when sending from more + * than one local address -- for example, when initiating connection + * migration as described in Section 9.2 or when probing a new + * network path as described in Section 9.1. + * + * Similarly, an endpoint MUST NOT reuse a connection ID when + * sending to more than one destination address. Due to network + * changes outside the control of its peer, an endpoint might + * receive packets from a new source address with the same + * Destination Connection ID field value, in which case it MAY + * continue to use the current connection ID with the new remote + * address while still sending from the same local address. + */ + require_new_cid = conn->dcid.current.cid.datalen && + ((new_cid_used && remote_addr_cmp) || !local_addr_eq); + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "non-probing packet was received from new remote address"); + + pto = conn_compute_pto(conn, &conn->pktns); + initial_pto = conn_compute_initial_pto(conn, &conn->pktns); + timeout = 3 * ngtcp2_max(pto, initial_pto); + + len = ngtcp2_ringbuf_len(&conn->dcid.bound.rb); + + for (i = 0; i < len; ++i) { + bound_dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, i); + if (ngtcp2_path_eq(&bound_dcid->ps.path, path)) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_CON, + "Found DCID which has already been bound to the new path"); + + ngtcp2_dcid_copy(&dcid, bound_dcid); + if (i == 0) { + ngtcp2_ringbuf_pop_front(&conn->dcid.bound.rb); + } else if (i == ngtcp2_ringbuf_len(&conn->dcid.bound.rb) - 1) { + ngtcp2_ringbuf_pop_back(&conn->dcid.bound.rb); + } else { + last = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, len - 1); + ngtcp2_dcid_copy(bound_dcid, last); + ngtcp2_ringbuf_pop_back(&conn->dcid.bound.rb); + } + require_new_cid = 0; + + if (dcid.cid.datalen) { + rv = conn_call_activate_dcid(conn, &dcid); + if (rv != 0) { + return rv; + } + } + break; + } + } + + if (i == len) { + if (require_new_cid) { + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb) == 0) { + return NGTCP2_ERR_CONN_ID_BLOCKED; + } + ngtcp2_dcid_copy(&dcid, ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0)); + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + + rv = conn_call_activate_dcid(conn, &dcid); + if (rv != 0) { + return rv; + } + } else { + /* Use the current DCID if a remote endpoint does not change + DCID. */ + ngtcp2_dcid_copy(&dcid, &conn->dcid.current); + dcid.bytes_sent = 0; + dcid.bytes_recv = 0; + dcid.flags &= (uint8_t)~NGTCP2_DCID_FLAG_PATH_VALIDATED; + } + } + + ngtcp2_dcid_set_path(&dcid, path); + dcid.bytes_recv += dgramlen; + + rv = ngtcp2_pv_new(&pv, &dcid, timeout, NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE, + &conn->log, conn->mem); + if (rv != 0) { + return rv; + } + + if (conn->pv && (conn->pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE)) { + ngtcp2_dcid_copy(&pv->fallback_dcid, &conn->pv->fallback_dcid); + pv->fallback_pto = conn->pv->fallback_pto; + /* Unset the flag bit so that conn_stop_pv does not retire + DCID. */ + conn->pv->flags &= (uint8_t)~NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE; + } else { + ngtcp2_dcid_copy(&pv->fallback_dcid, &conn->dcid.current); + pv->fallback_pto = pto; + } + + if (!local_addr_eq || (remote_addr_cmp & (NGTCP2_ADDR_COMPARE_FLAG_ADDR | + NGTCP2_ADDR_COMPARE_FLAG_FAMILY))) { + conn_reset_congestion_state(conn, ts); + } else { + /* For NAT rebinding, keep max_udp_payload_size since client most + likely does not send a padded PATH_CHALLENGE. */ + dcid.max_udp_payload_size = ngtcp2_max( + dcid.max_udp_payload_size, conn->dcid.current.max_udp_payload_size); + } + + ngtcp2_dcid_copy(&conn->dcid.current, &dcid); + + conn_reset_ecn_validation_state(conn); + + ngtcp2_conn_stop_pmtud(conn); + + if (conn->pv) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_PTV, + "path migration is aborted because new migration has started"); + rv = conn_abort_pv(conn, ts); + if (rv != 0) { + return rv; + } + } + + conn->pv = pv; + + return 0; +} + +/* + * conn_recv_pkt_from_new_path is called when a 1RTT packet is + * received from new path (not current path). This packet would be a + * packet which only contains probing frame, or reordered packet, or a + * path is being validated. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CONN_ID_BLOCKED + * No unused DCID is available + * NGTCP2_ERR_NOMEM + * Out of memory + */ +static int conn_recv_pkt_from_new_path(ngtcp2_conn *conn, + const ngtcp2_path *path, size_t dgramlen, + int path_challenge_recved, + ngtcp2_tstamp ts) { + ngtcp2_pv *pv = conn->pv; + ngtcp2_dcid *bound_dcid; + int rv; + + if (pv) { + if (ngtcp2_path_eq(&pv->dcid.ps.path, path)) { + pv->dcid.bytes_recv += dgramlen; + return 0; + } + + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + ngtcp2_path_eq(&pv->fallback_dcid.ps.path, path)) { + pv->fallback_dcid.bytes_recv += dgramlen; + return 0; + } + } + + if (!path_challenge_recved) { + return 0; + } + + rv = conn_bind_dcid(conn, &bound_dcid, path, ts); + if (rv != 0) { + return rv; + } + + ngtcp2_dcid_set_path(bound_dcid, path); + bound_dcid->bytes_recv += dgramlen; + + return 0; +} + +/* + * conn_recv_delayed_handshake_pkt processes the received Handshake + * packet which is received after handshake completed. This function + * does the minimal job, and its purpose is send acknowledgement of + * this packet to the peer. We assume that hd->type == + * NGTCP2_PKT_HANDSHAKE. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_FRAME_ENCODING + * Frame is badly formatted; or frame type is unknown. + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_DISCARD_PKT + * Packet was discarded. + * NGTCP2_ERR_ACK_FRAME + * ACK frame is malformed. + * NGTCP2_ERR_PROTO + * Frame that is not allowed in Handshake packet is received. + */ +static int +conn_recv_delayed_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_pkt_info *pi, + const ngtcp2_pkt_hd *hd, size_t pktlen, + const uint8_t *payload, size_t payloadlen, + ngtcp2_tstamp pkt_ts, ngtcp2_tstamp ts) { + ngtcp2_ssize nread; + ngtcp2_max_frame mfr; + ngtcp2_frame *fr = &mfr.fr; + int rv; + int require_ack = 0; + ngtcp2_pktns *pktns; + + assert(hd->type == NGTCP2_PKT_HANDSHAKE); + + pktns = conn->hs_pktns; + + if (payloadlen == 0) { + /* QUIC packet must contain at least one frame */ + return NGTCP2_ERR_PROTO; + } + + ngtcp2_qlog_pkt_received_start(&conn->qlog); + + for (; payloadlen;) { + nread = ngtcp2_pkt_decode_frame(fr, payload, payloadlen); + if (nread < 0) { + return (int)nread; + } + + payload += nread; + payloadlen -= (size_t)nread; + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + fr->ack.ack_delay = 0; + fr->ack.ack_delay_unscaled = 0; + break; + } + + ngtcp2_log_rx_fr(&conn->log, hd, fr); + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + if (!conn->server) { + conn->flags |= NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED; + } + rv = conn_recv_ack(conn, pktns, &fr->ack, pkt_ts, ts); + if (rv != 0) { + return rv; + } + break; + case NGTCP2_FRAME_PADDING: + break; + case NGTCP2_FRAME_CONNECTION_CLOSE: + rv = conn_recv_connection_close(conn, &fr->connection_close); + if (rv != 0) { + return rv; + } + break; + case NGTCP2_FRAME_CRYPTO: + case NGTCP2_FRAME_PING: + require_ack = 1; + break; + default: + return NGTCP2_ERR_PROTO; + } + + ngtcp2_qlog_write_frame(&conn->qlog, fr); + } + + ngtcp2_qlog_pkt_received_end(&conn->qlog, hd, pktlen); + + rv = pktns_commit_recv_pkt_num(pktns, hd->pkt_num, require_ack, pkt_ts); + if (rv != 0) { + return rv; + } + + pktns_increase_ecn_counts(pktns, pi); + + if (require_ack && + (++pktns->acktr.rx_npkt >= conn->local.settings.ack_thresh || + (pi->ecn & NGTCP2_ECN_MASK) == NGTCP2_ECN_CE)) { + ngtcp2_acktr_immediate_ack(&pktns->acktr); + } + + rv = ngtcp2_conn_sched_ack(conn, &pktns->acktr, hd->pkt_num, require_ack, + pkt_ts); + if (rv != 0) { + return rv; + } + + conn_restart_timer_on_read(conn, ts); + + ngtcp2_qlog_metrics_updated(&conn->qlog, &conn->cstat); + + return 0; +} + +/* + * conn_allow_path_change_under_disable_active_migration returns + * nonzero if a packet from |path| is acceptable under + * disable_active_migration is on. + */ +static int +conn_allow_path_change_under_disable_active_migration(ngtcp2_conn *conn, + const ngtcp2_path *path) { + uint32_t remote_addr_cmp; + const ngtcp2_preferred_addr *paddr; + ngtcp2_addr addr; + + assert(conn->server); + assert(conn->local.transport_params.disable_active_migration); + + /* If local address does not change, it must be passive migration + (NAT rebinding). */ + if (ngtcp2_addr_eq(&conn->dcid.current.ps.path.local, &path->local)) { + remote_addr_cmp = + ngtcp2_addr_compare(&conn->dcid.current.ps.path.remote, &path->remote); + + return (remote_addr_cmp | NGTCP2_ADDR_COMPARE_FLAG_PORT) == + NGTCP2_ADDR_COMPARE_FLAG_PORT; + } + + /* If local address changes, it must be one of the preferred + addresses. */ + + if (!conn->local.transport_params.preferred_address_present) { + return 0; + } + + paddr = &conn->local.transport_params.preferred_address; + + if (paddr->ipv4_present) { + ngtcp2_addr_init(&addr, (const ngtcp2_sockaddr *)&paddr->ipv4, + sizeof(paddr->ipv4)); + + if (ngtcp2_addr_eq(&addr, &path->local)) { + return 1; + } + } + + if (paddr->ipv6_present) { + ngtcp2_addr_init(&addr, (const ngtcp2_sockaddr *)&paddr->ipv6, + sizeof(paddr->ipv6)); + + if (ngtcp2_addr_eq(&addr, &path->local)) { + return 1; + } + } + + return 0; +} + +/* + * conn_recv_pkt processes a packet contained in the buffer pointed by + * |pkt| of length |pktlen|. |pkt| may contain multiple QUIC packets. + * This function only processes the first packet. |pkt_ts| is the + * timestamp when packet is received. |ts| should be the current + * time. Usually they are the same, but for buffered packets, + * |pkt_ts| would be earlier than |ts|. + * + * This function returns the number of bytes processed if it succeeds, + * or one of the following negative error codes: + * + * NGTCP2_ERR_DISCARD_PKT + * Packet was discarded because plain text header was malformed; + * or its payload could not be decrypted. + * NGTCP2_ERR_PROTO + * Packet is badly formatted; or 0RTT packet contains other than + * PADDING or STREAM frames; or other QUIC protocol violation is + * found. + * NGTCP2_ERR_CALLBACK_FAILURE + * User-defined callback function failed. + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_FRAME_ENCODING + * Frame is badly formatted; or frame type is unknown. + * NGTCP2_ERR_ACK_FRAME + * ACK frame is malformed. + * NGTCP2_ERR_STREAM_STATE + * Frame is received to the local stream which is not initiated. + * NGTCP2_ERR_STREAM_LIMIT + * Frame has remote stream ID which is strictly greater than the + * allowed limit. + * NGTCP2_ERR_FLOW_CONTROL + * Flow control limit is violated. + * NGTCP2_ERR_FINAL_SIZE + * Frame has strictly larger end offset than it is permitted. + */ +static ngtcp2_ssize conn_recv_pkt(ngtcp2_conn *conn, const ngtcp2_path *path, + const ngtcp2_pkt_info *pi, const uint8_t *pkt, + size_t pktlen, size_t dgramlen, + ngtcp2_tstamp pkt_ts, ngtcp2_tstamp ts) { + ngtcp2_pkt_hd hd; + int rv = 0; + size_t hdpktlen; + const uint8_t *payload; + size_t payloadlen; + ngtcp2_ssize nread, nwrite; + ngtcp2_max_frame mfr; + ngtcp2_frame *fr = &mfr.fr; + int require_ack = 0; + ngtcp2_crypto_aead *aead; + ngtcp2_crypto_cipher *hp; + ngtcp2_crypto_km *ckm; + ngtcp2_crypto_cipher_ctx *hp_ctx; + ngtcp2_hp_mask hp_mask; + ngtcp2_decrypt decrypt; + ngtcp2_pktns *pktns; + int non_probing_pkt = 0; + int key_phase_bit_changed = 0; + int force_decrypt_failure = 0; + int recv_ncid = 0; + int new_cid_used = 0; + int path_challenge_recved = 0; + + if (conn->server && conn->local.transport_params.disable_active_migration && + !ngtcp2_path_eq(&conn->dcid.current.ps.path, path) && + !conn_allow_path_change_under_disable_active_migration(conn, path)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet is discarded because active migration is disabled"); + + return NGTCP2_ERR_DISCARD_PKT; + } + + if (pkt[0] & NGTCP2_HEADER_FORM_BIT) { + nread = ngtcp2_pkt_decode_hd_long(&hd, pkt, pktlen); + if (nread < 0) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decode long header"); + return NGTCP2_ERR_DISCARD_PKT; + } + + if (pktlen < (size_t)nread + hd.len) { + return NGTCP2_ERR_DISCARD_PKT; + } + + assert(conn->negotiated_version); + + if (hd.version != conn->client_chosen_version && + hd.version != conn->negotiated_version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + pktlen = (size_t)nread + hd.len; + + /* Quoted from spec: if subsequent packets of those types include + a different Source Connection ID, they MUST be discarded. */ + if (!ngtcp2_cid_eq(&conn->dcid.current.cid, &hd.scid)) { + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched SCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + + switch (hd.type) { + case NGTCP2_PKT_INITIAL: + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "delayed Initial packet was discarded"); + return (ngtcp2_ssize)pktlen; + case NGTCP2_PKT_HANDSHAKE: + if (hd.version != conn->negotiated_version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (!conn->hs_pktns) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "delayed Handshake packet was discarded"); + return (ngtcp2_ssize)pktlen; + } + + pktns = conn->hs_pktns; + aead = &pktns->crypto.ctx.aead; + hp = &pktns->crypto.ctx.hp; + ckm = pktns->crypto.rx.ckm; + hp_ctx = &pktns->crypto.rx.hp_ctx; + hp_mask = conn->callbacks.hp_mask; + decrypt = conn->callbacks.decrypt; + break; + case NGTCP2_PKT_0RTT: + if (!conn->server || hd.version != conn->client_chosen_version) { + return NGTCP2_ERR_DISCARD_PKT; + } + + if (!conn->early.ckm) { + return (ngtcp2_ssize)pktlen; + } + + pktns = &conn->pktns; + aead = &conn->early.ctx.aead; + hp = &conn->early.ctx.hp; + ckm = conn->early.ckm; + hp_ctx = &conn->early.hp_ctx; + hp_mask = conn->callbacks.hp_mask; + decrypt = conn->callbacks.decrypt; + break; + default: + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet type 0x%02x was ignored", hd.type); + return (ngtcp2_ssize)pktlen; + } + } else { + nread = ngtcp2_pkt_decode_hd_short(&hd, pkt, pktlen, conn->oscid.datalen); + if (nread < 0) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decode short header"); + return NGTCP2_ERR_DISCARD_PKT; + } + + pktns = &conn->pktns; + aead = &pktns->crypto.ctx.aead; + hp = &pktns->crypto.ctx.hp; + ckm = pktns->crypto.rx.ckm; + hp_ctx = &pktns->crypto.rx.hp_ctx; + hp_mask = conn->callbacks.hp_mask; + decrypt = conn->callbacks.decrypt; + } + + rv = conn_ensure_decrypt_hp_buffer(conn, (size_t)nread + 4); + if (rv != 0) { + return rv; + } + + nwrite = decrypt_hp(&hd, conn->crypto.decrypt_hp_buf.base, hp, pkt, pktlen, + (size_t)nread, hp_ctx, hp_mask); + if (nwrite < 0) { + if (ngtcp2_err_is_fatal((int)nwrite)) { + return nwrite; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decrypt packet number"); + return NGTCP2_ERR_DISCARD_PKT; + } + + hdpktlen = (size_t)nwrite; + payload = pkt + hdpktlen; + payloadlen = pktlen - hdpktlen; + + hd.pkt_num = ngtcp2_pkt_adjust_pkt_num(pktns->rx.max_pkt_num, hd.pkt_num, + pkt_num_bits(hd.pkt_numlen)); + if (hd.pkt_num > NGTCP2_MAX_PKT_NUM) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "pkn=%" PRId64 " is greater than maximum pkn", hd.pkt_num); + return NGTCP2_ERR_DISCARD_PKT; + } + + ngtcp2_log_rx_pkt_hd(&conn->log, &hd); + + if (hd.type == NGTCP2_PKT_1RTT) { + key_phase_bit_changed = conn_key_phase_changed(conn, &hd); + } + + rv = conn_ensure_decrypt_buffer(conn, payloadlen); + if (rv != 0) { + return rv; + } + + if (key_phase_bit_changed) { + assert(hd.type == NGTCP2_PKT_1RTT); + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, "unexpected KEY_PHASE"); + + if (ckm->pkt_num > hd.pkt_num) { + if (conn->crypto.key_update.old_rx_ckm) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "decrypting with old key"); + ckm = conn->crypto.key_update.old_rx_ckm; + } else { + force_decrypt_failure = 1; + } + } else if (pktns->rx.max_pkt_num < hd.pkt_num) { + assert(ckm->pkt_num < hd.pkt_num); + if (!conn->crypto.key_update.new_rx_ckm) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "new key is not available"); + force_decrypt_failure = 1; + } else { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "decrypting with new key"); + ckm = conn->crypto.key_update.new_rx_ckm; + } + } else { + force_decrypt_failure = 1; + } + } + + nwrite = decrypt_pkt(conn->crypto.decrypt_buf.base, aead, payload, payloadlen, + conn->crypto.decrypt_hp_buf.base, hdpktlen, hd.pkt_num, + ckm, decrypt); + + if (force_decrypt_failure) { + nwrite = NGTCP2_ERR_DECRYPT; + } + + if (nwrite < 0) { + if (ngtcp2_err_is_fatal((int)nwrite)) { + return nwrite; + } + + assert(NGTCP2_ERR_DECRYPT == nwrite); + + if (hd.type == NGTCP2_PKT_1RTT && + ++conn->crypto.decryption_failure_count >= + pktns->crypto.ctx.max_decryption_failure) { + return NGTCP2_ERR_AEAD_LIMIT_REACHED; + } + + if (hd.flags & NGTCP2_PKT_FLAG_LONG_FORM) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decrypt packet payload"); + return NGTCP2_ERR_DISCARD_PKT; + } + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "could not decrypt packet payload"); + return NGTCP2_ERR_DISCARD_PKT; + } + + rv = ngtcp2_pkt_verify_reserved_bits(conn->crypto.decrypt_hp_buf.base[0]); + if (rv != 0) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet has incorrect reserved bits"); + + return NGTCP2_ERR_PROTO; + } + + if (pktns_pkt_num_is_duplicate(pktns, hd.pkt_num)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was discarded because of duplicated packet number"); + return NGTCP2_ERR_DISCARD_PKT; + } + + payload = conn->crypto.decrypt_buf.base; + payloadlen = (size_t)nwrite; + + if (payloadlen == 0) { + /* QUIC packet must contain at least one frame */ + return NGTCP2_ERR_PROTO; + } + + if (hd.flags & NGTCP2_PKT_FLAG_LONG_FORM) { + switch (hd.type) { + case NGTCP2_PKT_HANDSHAKE: + rv = conn_verify_dcid(conn, NULL, &hd); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched DCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + + rv = conn_recv_delayed_handshake_pkt(conn, pi, &hd, pktlen, payload, + payloadlen, pkt_ts, ts); + if (rv < 0) { + return (ngtcp2_ssize)rv; + } + + return (ngtcp2_ssize)pktlen; + case NGTCP2_PKT_0RTT: + if (!ngtcp2_cid_eq(&conn->rcid, &hd.dcid)) { + rv = conn_verify_dcid(conn, NULL, &hd); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched DCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + } + break; + default: + /* Unreachable */ + ngtcp2_unreachable(); + } + } else { + rv = conn_verify_dcid(conn, &new_cid_used, &hd); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "packet was ignored because of mismatched DCID"); + return NGTCP2_ERR_DISCARD_PKT; + } + } + + ngtcp2_qlog_pkt_received_start(&conn->qlog); + + for (; payloadlen;) { + nread = ngtcp2_pkt_decode_frame(fr, payload, payloadlen); + if (nread < 0) { + return nread; + } + + payload += nread; + payloadlen -= (size_t)nread; + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + if ((hd.flags & NGTCP2_PKT_FLAG_LONG_FORM) && + hd.type == NGTCP2_PKT_0RTT) { + return NGTCP2_ERR_PROTO; + } + assert(conn->remote.transport_params); + assign_recved_ack_delay_unscaled( + &fr->ack, conn->remote.transport_params->ack_delay_exponent); + break; + } + + ngtcp2_log_rx_fr(&conn->log, &hd, fr); + + if (hd.type == NGTCP2_PKT_0RTT) { + switch (fr->type) { + case NGTCP2_FRAME_PADDING: + case NGTCP2_FRAME_PING: + case NGTCP2_FRAME_RESET_STREAM: + case NGTCP2_FRAME_STOP_SENDING: + case NGTCP2_FRAME_STREAM: + case NGTCP2_FRAME_MAX_DATA: + case NGTCP2_FRAME_MAX_STREAM_DATA: + case NGTCP2_FRAME_MAX_STREAMS_BIDI: + case NGTCP2_FRAME_MAX_STREAMS_UNI: + case NGTCP2_FRAME_DATA_BLOCKED: + case NGTCP2_FRAME_STREAM_DATA_BLOCKED: + case NGTCP2_FRAME_STREAMS_BLOCKED_BIDI: + case NGTCP2_FRAME_STREAMS_BLOCKED_UNI: + case NGTCP2_FRAME_NEW_CONNECTION_ID: + case NGTCP2_FRAME_PATH_CHALLENGE: + case NGTCP2_FRAME_CONNECTION_CLOSE: + case NGTCP2_FRAME_CONNECTION_CLOSE_APP: + case NGTCP2_FRAME_DATAGRAM: + case NGTCP2_FRAME_DATAGRAM_LEN: + break; + default: + return NGTCP2_ERR_PROTO; + } + } + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + case NGTCP2_FRAME_PADDING: + case NGTCP2_FRAME_CONNECTION_CLOSE: + case NGTCP2_FRAME_CONNECTION_CLOSE_APP: + break; + default: + require_ack = 1; + } + + switch (fr->type) { + case NGTCP2_FRAME_ACK: + case NGTCP2_FRAME_ACK_ECN: + if (!conn->server) { + conn->flags |= NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED; + } + rv = conn_recv_ack(conn, pktns, &fr->ack, pkt_ts, ts); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_STREAM: + rv = conn_recv_stream(conn, &fr->stream); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_CRYPTO: + rv = conn_recv_crypto(conn, NGTCP2_CRYPTO_LEVEL_APPLICATION, + &pktns->crypto.strm, &fr->crypto); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_RESET_STREAM: + rv = conn_recv_reset_stream(conn, &fr->reset_stream); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_STOP_SENDING: + rv = conn_recv_stop_sending(conn, &fr->stop_sending); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_MAX_STREAM_DATA: + rv = conn_recv_max_stream_data(conn, &fr->max_stream_data); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_MAX_DATA: + conn_recv_max_data(conn, &fr->max_data); + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_MAX_STREAMS_BIDI: + case NGTCP2_FRAME_MAX_STREAMS_UNI: + rv = conn_recv_max_streams(conn, &fr->max_streams); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_CONNECTION_CLOSE: + case NGTCP2_FRAME_CONNECTION_CLOSE_APP: + rv = conn_recv_connection_close(conn, &fr->connection_close); + if (rv != 0) { + return rv; + } + break; + case NGTCP2_FRAME_PING: + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_PATH_CHALLENGE: + conn_recv_path_challenge(conn, path, &fr->path_challenge); + path_challenge_recved = 1; + break; + case NGTCP2_FRAME_PATH_RESPONSE: + rv = conn_recv_path_response(conn, &fr->path_response, ts); + if (rv != 0) { + return rv; + } + break; + case NGTCP2_FRAME_NEW_CONNECTION_ID: + rv = conn_recv_new_connection_id(conn, &fr->new_connection_id); + if (rv != 0) { + return rv; + } + recv_ncid = 1; + break; + case NGTCP2_FRAME_RETIRE_CONNECTION_ID: + rv = conn_recv_retire_connection_id(conn, &hd, &fr->retire_connection_id, + ts); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_NEW_TOKEN: + rv = conn_recv_new_token(conn, &fr->new_token); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_HANDSHAKE_DONE: + rv = conn_recv_handshake_done(conn, ts); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_STREAMS_BLOCKED_BIDI: + rv = conn_recv_streams_blocked_bidi(conn, &fr->streams_blocked); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_STREAMS_BLOCKED_UNI: + rv = conn_recv_streams_blocked_uni(conn, &fr->streams_blocked); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_DATA_BLOCKED: + /* TODO Not implemented yet */ + non_probing_pkt = 1; + break; + case NGTCP2_FRAME_DATAGRAM: + case NGTCP2_FRAME_DATAGRAM_LEN: + if ((uint64_t)nread > + conn->local.transport_params.max_datagram_frame_size) { + return NGTCP2_ERR_PROTO; + } + rv = conn_recv_datagram(conn, &fr->datagram); + if (rv != 0) { + return rv; + } + non_probing_pkt = 1; + break; + } + + ngtcp2_qlog_write_frame(&conn->qlog, fr); + } + + ngtcp2_qlog_pkt_received_end(&conn->qlog, &hd, pktlen); + + if (recv_ncid) { + rv = conn_post_process_recv_new_connection_id(conn, ts); + if (rv != 0) { + return rv; + } + } + + if (conn->server && hd.type == NGTCP2_PKT_1RTT && + !ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + if (non_probing_pkt && pktns->rx.max_pkt_num < hd.pkt_num && + !conn_path_validation_in_progress(conn, path)) { + rv = conn_recv_non_probing_pkt_on_new_path(conn, path, dgramlen, + new_cid_used, ts); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + + /* DCID is not available. Just continue. */ + assert(NGTCP2_ERR_CONN_ID_BLOCKED == rv); + } + } else { + rv = conn_recv_pkt_from_new_path(conn, path, dgramlen, + path_challenge_recved, ts); + if (rv != 0) { + if (ngtcp2_err_is_fatal(rv)) { + return rv; + } + + /* DCID is not available. Just continue. */ + assert(NGTCP2_ERR_CONN_ID_BLOCKED == rv); + } + } + } + + if (hd.type == NGTCP2_PKT_1RTT) { + if (ckm == conn->crypto.key_update.new_rx_ckm) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, "rotate keys"); + conn_rotate_keys(conn, hd.pkt_num, /* initiator = */ 0); + } else if (ckm->pkt_num > hd.pkt_num) { + ckm->pkt_num = hd.pkt_num; + } + + if (conn->server && conn->early.ckm && + conn->early.discard_started_ts == UINT64_MAX) { + conn->early.discard_started_ts = ts; + } + + if (ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + conn_update_keep_alive_last_ts(conn, ts); + } + } + + rv = pktns_commit_recv_pkt_num(pktns, hd.pkt_num, require_ack, pkt_ts); + if (rv != 0) { + return rv; + } + + pktns_increase_ecn_counts(pktns, pi); + + if (require_ack && + (++pktns->acktr.rx_npkt >= conn->local.settings.ack_thresh || + (pi->ecn & NGTCP2_ECN_MASK) == NGTCP2_ECN_CE)) { + ngtcp2_acktr_immediate_ack(&pktns->acktr); + } + + rv = ngtcp2_conn_sched_ack(conn, &pktns->acktr, hd.pkt_num, require_ack, + pkt_ts); + if (rv != 0) { + return rv; + } + + conn_restart_timer_on_read(conn, ts); + + ngtcp2_qlog_metrics_updated(&conn->qlog, &conn->cstat); + + return conn->state == NGTCP2_CS_DRAINING ? NGTCP2_ERR_DRAINING + : (ngtcp2_ssize)pktlen; +} + +/* + * conn_process_buffered_protected_pkt processes buffered 0RTT or 1RTT + * packets. + * + * This function returns 0 if it succeeds, or the same negative error + * codes from conn_recv_pkt. + */ +static int conn_process_buffered_protected_pkt(ngtcp2_conn *conn, + ngtcp2_pktns *pktns, + ngtcp2_tstamp ts) { + ngtcp2_ssize nread; + ngtcp2_pkt_chain **ppc, *next; + int rv; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "processing buffered protected packet"); + + for (ppc = &pktns->rx.buffed_pkts; *ppc;) { + next = (*ppc)->next; + nread = conn_recv_pkt(conn, &(*ppc)->path.path, &(*ppc)->pi, (*ppc)->pkt, + (*ppc)->pktlen, (*ppc)->dgramlen, (*ppc)->ts, ts); + if (nread < 0 && !ngtcp2_err_is_fatal((int)nread) && + nread != NGTCP2_ERR_DRAINING) { + /* TODO We don't know this is the first QUIC packet in a + datagram. */ + rv = conn_on_stateless_reset(conn, &(*ppc)->path.path, (*ppc)->pkt, + (*ppc)->pktlen); + if (rv == 0) { + ngtcp2_pkt_chain_del(*ppc, conn->mem); + *ppc = next; + return NGTCP2_ERR_DRAINING; + } + } + + ngtcp2_pkt_chain_del(*ppc, conn->mem); + *ppc = next; + if (nread < 0) { + if (nread == NGTCP2_ERR_DISCARD_PKT) { + continue; + } + return (int)nread; + } + } + + return 0; +} + +/* + * conn_process_buffered_handshake_pkt processes buffered Handshake + * packets. + * + * This function returns 0 if it succeeds, or the same negative error + * codes from conn_recv_handshake_pkt. + */ +static int conn_process_buffered_handshake_pkt(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + ngtcp2_pktns *pktns = conn->hs_pktns; + ngtcp2_ssize nread; + ngtcp2_pkt_chain **ppc, *next; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "processing buffered handshake packet"); + + for (ppc = &pktns->rx.buffed_pkts; *ppc;) { + next = (*ppc)->next; + nread = conn_recv_handshake_pkt(conn, &(*ppc)->path.path, &(*ppc)->pi, + (*ppc)->pkt, (*ppc)->pktlen, + (*ppc)->dgramlen, (*ppc)->ts, ts); + ngtcp2_pkt_chain_del(*ppc, conn->mem); + *ppc = next; + if (nread < 0) { + if (nread == NGTCP2_ERR_DISCARD_PKT) { + continue; + } + return (int)nread; + } + } + + return 0; +} + +static void conn_sync_stream_id_limit(ngtcp2_conn *conn) { + ngtcp2_transport_params *params = conn->remote.transport_params; + + assert(params); + + conn->local.bidi.max_streams = params->initial_max_streams_bidi; + conn->local.uni.max_streams = params->initial_max_streams_uni; +} + +static int strm_set_max_offset(void *data, void *ptr) { + ngtcp2_conn *conn = ptr; + ngtcp2_transport_params *params = conn->remote.transport_params; + ngtcp2_strm *strm = data; + uint64_t max_offset; + int rv; + + assert(params); + + if (!conn_local_stream(conn, strm->stream_id)) { + return 0; + } + + if (bidi_stream(strm->stream_id)) { + max_offset = params->initial_max_stream_data_bidi_remote; + } else { + max_offset = params->initial_max_stream_data_uni; + } + + if (strm->tx.max_offset < max_offset) { + strm->tx.max_offset = max_offset; + + /* Don't call callback if stream is half-closed local */ + if (strm->flags & NGTCP2_STRM_FLAG_SHUT_WR) { + return 0; + } + + rv = conn_call_extend_max_stream_data(conn, strm, strm->stream_id, + strm->tx.max_offset); + if (rv != 0) { + return rv; + } + } + + return 0; +} + +static int conn_sync_stream_data_limit(ngtcp2_conn *conn) { + return ngtcp2_map_each(&conn->strms, strm_set_max_offset, conn); +} + +/* + * conn_handshake_completed is called once cryptographic handshake has + * completed. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_CALLBACK_FAILURE + * User callback failed. + */ +static int conn_handshake_completed(ngtcp2_conn *conn) { + int rv; + + conn->flags |= NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED_HANDLED; + + rv = conn_call_handshake_completed(conn); + if (rv != 0) { + return rv; + } + + if (conn->local.bidi.max_streams > 0) { + rv = conn_call_extend_max_local_streams_bidi(conn, + conn->local.bidi.max_streams); + if (rv != 0) { + return rv; + } + } + if (conn->local.uni.max_streams > 0) { + rv = conn_call_extend_max_local_streams_uni(conn, + conn->local.uni.max_streams); + if (rv != 0) { + return rv; + } + } + + return 0; +} + +/* + * conn_recv_cpkt processes compound packet after handshake. The + * buffer pointed by |pkt| might contain multiple packets. The 1RTT + * packet must be the last one because it does not have payload length + * field. + * + * This function returns 0 if it succeeds, or the same negative error + * codes from conn_recv_pkt except for NGTCP2_ERR_DISCARD_PKT. + */ +static int conn_recv_cpkt(ngtcp2_conn *conn, const ngtcp2_path *path, + const ngtcp2_pkt_info *pi, const uint8_t *pkt, + size_t pktlen, ngtcp2_tstamp ts) { + ngtcp2_ssize nread; + int rv; + const uint8_t *origpkt = pkt; + size_t dgramlen = pktlen; + + if (ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + conn->dcid.current.bytes_recv += dgramlen; + } + + while (pktlen) { + nread = conn_recv_pkt(conn, path, pi, pkt, pktlen, dgramlen, ts, ts); + if (nread < 0) { + if (ngtcp2_err_is_fatal((int)nread)) { + return (int)nread; + } + + if (nread == NGTCP2_ERR_DRAINING) { + return NGTCP2_ERR_DRAINING; + } + + if (origpkt == pkt) { + rv = conn_on_stateless_reset(conn, path, origpkt, dgramlen); + if (rv == 0) { + return NGTCP2_ERR_DRAINING; + } + } + if (nread == NGTCP2_ERR_DISCARD_PKT) { + return 0; + } + return (int)nread; + } + + assert(pktlen >= (size_t)nread); + pkt += nread; + pktlen -= (size_t)nread; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT, + "read packet %td left %zu", nread, pktlen); + } + + return 0; +} + +/* + * conn_is_retired_path returns nonzero if |path| is included in + * retired path list. + */ +static int conn_is_retired_path(ngtcp2_conn *conn, const ngtcp2_path *path) { + size_t i, len = ngtcp2_ringbuf_len(&conn->dcid.retired.rb); + ngtcp2_dcid *dcid; + + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.retired.rb, i); + if (ngtcp2_path_eq(&dcid->ps.path, path)) { + return 1; + } + } + + return 0; +} + +/* + * conn_enqueue_handshake_done enqueues HANDSHAKE_DONE frame for + * transmission. + */ +static int conn_enqueue_handshake_done(ngtcp2_conn *conn) { + ngtcp2_pktns *pktns = &conn->pktns; + ngtcp2_frame_chain *nfrc; + int rv; + + assert(conn->server); + + rv = ngtcp2_frame_chain_objalloc_new(&nfrc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + nfrc->fr.type = NGTCP2_FRAME_HANDSHAKE_DONE; + nfrc->next = pktns->tx.frq; + pktns->tx.frq = nfrc; + + return 0; +} + +/** + * @function + * + * `conn_read_handshake` performs QUIC cryptographic handshake by + * reading given data. |pkt| points to the buffer to read and + * |pktlen| is the length of the buffer. |path| is the network path. + * + * This function returns the number of bytes processed. Unless the + * last packet is 1RTT packet and an application decryption key has + * been installed, it returns |pktlen| if it succeeds. If it finds + * 1RTT packet and an application decryption key has been installed, + * it returns the number of bytes just before 1RTT packet begins. + * + * This function returns the number of bytes processed if it succeeds, + * or one of the following negative error codes: (TBD). + */ +static ngtcp2_ssize conn_read_handshake(ngtcp2_conn *conn, + const ngtcp2_path *path, + const ngtcp2_pkt_info *pi, + const uint8_t *pkt, size_t pktlen, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_ssize nread; + + switch (conn->state) { + case NGTCP2_CS_CLIENT_INITIAL: + /* TODO Better to log something when we ignore input */ + return (ngtcp2_ssize)pktlen; + case NGTCP2_CS_CLIENT_WAIT_HANDSHAKE: + nread = conn_recv_handshake_cpkt(conn, path, pi, pkt, pktlen, ts); + if (nread < 0) { + return nread; + } + + if (conn->state == NGTCP2_CS_CLIENT_INITIAL) { + /* Retry packet was received */ + return (ngtcp2_ssize)pktlen; + } + + assert(conn->hs_pktns); + + if (conn->hs_pktns->crypto.rx.ckm && conn->in_pktns) { + rv = conn_process_buffered_handshake_pkt(conn, ts); + if (rv != 0) { + return rv; + } + } + + if (conn_is_handshake_completed(conn) && + !(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED_HANDLED)) { + rv = conn_handshake_completed(conn); + if (rv != 0) { + return rv; + } + + rv = conn_process_buffered_protected_pkt(conn, &conn->pktns, ts); + if (rv != 0) { + return rv; + } + } + + return nread; + case NGTCP2_CS_SERVER_INITIAL: + nread = conn_recv_handshake_cpkt(conn, path, pi, pkt, pktlen, ts); + if (nread < 0) { + return nread; + } + + /* + * Client ServerHello might not fit into single Initial packet + * (e.g., resuming session with client authentication). If we get + * Client Initial which does not increase offset or it is 0RTT + * packet buffered, perform address validation in order to buffer + * validated data only. + */ + if (ngtcp2_strm_rx_offset(&conn->in_pktns->crypto.strm) == 0) { + if (conn->in_pktns->crypto.strm.rx.rob && + ngtcp2_rob_data_buffered(conn->in_pktns->crypto.strm.rx.rob)) { + /* Address has been validated with token */ + if (conn->local.settings.tokenlen) { + return nread; + } + return NGTCP2_ERR_RETRY; + } + if (conn->in_pktns->rx.buffed_pkts) { + /* 0RTT is buffered, force retry */ + return NGTCP2_ERR_RETRY; + } + /* If neither CRYPTO frame nor 0RTT packet is processed, just + drop connection. */ + return NGTCP2_ERR_DROP_CONN; + } + + /* Process re-ordered 0-RTT packets which arrived before Initial + packet. */ + if (conn->early.ckm) { + assert(conn->in_pktns); + + rv = conn_process_buffered_protected_pkt(conn, conn->in_pktns, ts); + if (rv != 0) { + return rv; + } + } + + return nread; + case NGTCP2_CS_SERVER_WAIT_HANDSHAKE: + nread = conn_recv_handshake_cpkt(conn, path, pi, pkt, pktlen, ts); + if (nread < 0) { + return nread; + } + + if (conn->hs_pktns->crypto.rx.ckm) { + rv = conn_process_buffered_handshake_pkt(conn, ts); + if (rv != 0) { + return rv; + } + } + + if (conn->hs_pktns->rx.max_pkt_num != -1) { + conn_discard_initial_state(conn, ts); + } + + if (!conn_is_handshake_completed(conn)) { + /* If server hits amplification limit, it cancels loss detection + timer. If server receives a packet from client, the limit is + increased and server can send more. If server has + ack-eliciting Initial or Handshake packets, it should resend + it if timer fired but timer is not armed in this case. So + instead of resending Initial/Handshake packets, if server has + 1RTT data to send, it might send them and then might hit + amplification limit again until it hits stream data limit. + Initial/Handshake data is not resent. In order to avoid this + situation, try to arm loss detection and check the expiry + here so that on next write call, we can resend + Initial/Handshake first. */ + if (conn->cstat.loss_detection_timer == UINT64_MAX) { + ngtcp2_conn_set_loss_detection_timer(conn, ts); + if (ngtcp2_conn_loss_detection_expiry(conn) <= ts) { + rv = ngtcp2_conn_on_loss_detection_timer(conn, ts); + if (rv != 0) { + return rv; + } + } + } + + if ((size_t)nread < pktlen) { + /* We have 1RTT packet and application rx key, but the + handshake has not completed yet. */ + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "buffering 1RTT packet len=%zu", + pktlen - (size_t)nread); + + rv = conn_buffer_pkt(conn, &conn->pktns, path, pi, pkt + nread, + pktlen - (size_t)nread, pktlen, ts); + if (rv != 0) { + assert(ngtcp2_err_is_fatal(rv)); + return rv; + } + + return (ngtcp2_ssize)pktlen; + } + + return nread; + } + + if (!(conn->flags & NGTCP2_CONN_FLAG_TRANSPORT_PARAM_RECVED)) { + return NGTCP2_ERR_REQUIRED_TRANSPORT_PARAM; + } + + rv = conn_handshake_completed(conn); + if (rv != 0) { + return rv; + } + conn->state = NGTCP2_CS_POST_HANDSHAKE; + + rv = conn_call_activate_dcid(conn, &conn->dcid.current); + if (rv != 0) { + return rv; + } + + rv = conn_process_buffered_protected_pkt(conn, &conn->pktns, ts); + if (rv != 0) { + return rv; + } + + conn_discard_handshake_state(conn, ts); + + rv = conn_enqueue_handshake_done(conn); + if (rv != 0) { + return rv; + } + + if (!conn->local.settings.no_pmtud) { + rv = conn_start_pmtud(conn); + if (rv != 0) { + return rv; + } + } + + conn->pktns.rtb.persistent_congestion_start_ts = ts; + + /* Re-arm loss detection timer here after handshake has been + confirmed. */ + ngtcp2_conn_set_loss_detection_timer(conn, ts); + + return nread; + case NGTCP2_CS_CLOSING: + return NGTCP2_ERR_CLOSING; + case NGTCP2_CS_DRAINING: + return NGTCP2_ERR_DRAINING; + default: + return (ngtcp2_ssize)pktlen; + } +} + +int ngtcp2_conn_read_pkt_versioned(ngtcp2_conn *conn, const ngtcp2_path *path, + int pkt_info_version, + const ngtcp2_pkt_info *pi, + const uint8_t *pkt, size_t pktlen, + ngtcp2_tstamp ts) { + int rv = 0; + ngtcp2_ssize nread = 0; + const ngtcp2_pkt_info zero_pi = {0}; + (void)pkt_info_version; + + assert(!(conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING)); + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, "recv packet len=%zu", + pktlen); + + if (pktlen == 0) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + /* client does not expect a packet from unknown path. */ + if (!conn->server && !ngtcp2_path_eq(&conn->dcid.current.ps.path, path) && + (!conn->pv || !ngtcp2_path_eq(&conn->pv->dcid.ps.path, path)) && + !conn_is_retired_path(conn, path)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "ignore packet from unknown path"); + return 0; + } + + if (!pi) { + pi = &zero_pi; + } + + switch (conn->state) { + case NGTCP2_CS_CLIENT_INITIAL: + case NGTCP2_CS_CLIENT_WAIT_HANDSHAKE: + case NGTCP2_CS_CLIENT_TLS_HANDSHAKE_FAILED: + nread = conn_read_handshake(conn, path, pi, pkt, pktlen, ts); + if (nread < 0) { + return (int)nread; + } + + if ((size_t)nread == pktlen) { + return 0; + } + + assert(conn->pktns.crypto.rx.ckm); + + pkt += nread; + pktlen -= (size_t)nread; + + break; + case NGTCP2_CS_SERVER_INITIAL: + case NGTCP2_CS_SERVER_WAIT_HANDSHAKE: + case NGTCP2_CS_SERVER_TLS_HANDSHAKE_FAILED: + if (!ngtcp2_path_eq(&conn->dcid.current.ps.path, path)) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "ignore packet from unknown path during handshake"); + + if (conn->state == NGTCP2_CS_SERVER_INITIAL && + ngtcp2_strm_rx_offset(&conn->in_pktns->crypto.strm) == 0 && + (!conn->in_pktns->crypto.strm.rx.rob || + !ngtcp2_rob_data_buffered(conn->in_pktns->crypto.strm.rx.rob))) { + return NGTCP2_ERR_DROP_CONN; + } + + return 0; + } + + nread = conn_read_handshake(conn, path, pi, pkt, pktlen, ts); + if (nread < 0) { + return (int)nread; + } + + if ((size_t)nread == pktlen) { + return 0; + } + + assert(conn->pktns.crypto.rx.ckm); + + pkt += nread; + pktlen -= (size_t)nread; + + break; + case NGTCP2_CS_CLOSING: + return NGTCP2_ERR_CLOSING; + case NGTCP2_CS_DRAINING: + return NGTCP2_ERR_DRAINING; + case NGTCP2_CS_POST_HANDSHAKE: + rv = conn_prepare_key_update(conn, ts); + if (rv != 0) { + return rv; + } + break; + default: + ngtcp2_unreachable(); + } + + return conn_recv_cpkt(conn, path, pi, pkt, pktlen, ts); +} + +/* + * conn_check_pkt_num_exhausted returns nonzero if packet number is + * exhausted in at least one of packet number space. + */ +static int conn_check_pkt_num_exhausted(ngtcp2_conn *conn) { + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + + return (in_pktns && in_pktns->tx.last_pkt_num == NGTCP2_MAX_PKT_NUM) || + (hs_pktns && hs_pktns->tx.last_pkt_num == NGTCP2_MAX_PKT_NUM) || + conn->pktns.tx.last_pkt_num == NGTCP2_MAX_PKT_NUM; +} + +/* + * conn_retransmit_retry_early retransmits 0RTT packet after Retry is + * received from server. + */ +static ngtcp2_ssize conn_retransmit_retry_early(ngtcp2_conn *conn, + ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + uint8_t flags, + ngtcp2_tstamp ts) { + return conn_write_pkt(conn, pi, dest, destlen, NULL, NGTCP2_PKT_0RTT, flags, + ts); +} + +/* + * conn_handshake_probe_left returns nonzero if there are probe + * packets to be sent for Initial or Handshake packet number space + * left. + */ +static int conn_handshake_probe_left(ngtcp2_conn *conn) { + return (conn->in_pktns && conn->in_pktns->rtb.probe_pkt_left) || + conn->hs_pktns->rtb.probe_pkt_left; +} + +/* + * conn_validate_early_transport_params_limits validates that the + * limits in transport parameters remembered by client for early data + * are not reduced. This function is only used by client and should + * only be called when early data is accepted by server. + */ +static int conn_validate_early_transport_params_limits(ngtcp2_conn *conn) { + const ngtcp2_transport_params *params = conn->remote.transport_params; + + assert(!conn->server); + assert(params); + + if (conn->early.transport_params.active_connection_id_limit > + params->active_connection_id_limit || + conn->early.transport_params.initial_max_data > + params->initial_max_data || + conn->early.transport_params.initial_max_stream_data_bidi_local > + params->initial_max_stream_data_bidi_local || + conn->early.transport_params.initial_max_stream_data_bidi_remote > + params->initial_max_stream_data_bidi_remote || + conn->early.transport_params.initial_max_stream_data_uni > + params->initial_max_stream_data_uni || + conn->early.transport_params.initial_max_streams_bidi > + params->initial_max_streams_bidi || + conn->early.transport_params.initial_max_streams_uni > + params->initial_max_streams_uni || + conn->early.transport_params.max_datagram_frame_size > + params->max_datagram_frame_size) { + return NGTCP2_ERR_PROTO; + } + + return 0; +} + +/* + * conn_write_handshake writes QUIC handshake packets to the buffer + * pointed by |dest| of length |destlen|. |write_datalen| specifies + * the expected length of 0RTT or 1RTT packet payload. Specify 0 to + * |write_datalen| if there is no such data. + * + * This function returns the number of bytes written to the buffer, or + * one of the following negative error codes: + * + * NGTCP2_ERR_PKT_NUM_EXHAUSTED + * Packet number is exhausted. + * NGTCP2_ERR_NOMEM + * Out of memory + * NGTCP2_ERR_REQUIRED_TRANSPORT_PARAM + * Required transport parameter is missing. + * NGTCP2_CS_CLOSING + * Connection is in closing state. + * NGTCP2_CS_DRAINING + * Connection is in draining state. + * + * In addition to the above negative error codes, the same error codes + * from conn_recv_pkt may also be returned. + */ +static ngtcp2_ssize conn_write_handshake(ngtcp2_conn *conn, ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + uint64_t write_datalen, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_ssize res = 0, nwrite = 0, early_spktlen = 0; + size_t origlen = destlen; + uint64_t pending_early_datalen; + ngtcp2_dcid *dcid; + ngtcp2_preferred_addr *paddr; + + switch (conn->state) { + case NGTCP2_CS_CLIENT_INITIAL: + pending_early_datalen = conn_retry_early_payloadlen(conn); + if (pending_early_datalen) { + write_datalen = pending_early_datalen; + } + + if (!(conn->flags & NGTCP2_CONN_FLAG_RECV_RETRY)) { + nwrite = + conn_write_client_initial(conn, pi, dest, destlen, write_datalen, ts); + if (nwrite <= 0) { + return nwrite; + } + } else { + nwrite = conn_write_handshake_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_INITIAL, + NGTCP2_WRITE_PKT_FLAG_NONE, write_datalen, ts); + if (nwrite < 0) { + return nwrite; + } + } + + if (pending_early_datalen) { + early_spktlen = conn_retransmit_retry_early( + conn, pi, dest + nwrite, destlen - (size_t)nwrite, + nwrite ? NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING + : NGTCP2_WRITE_PKT_FLAG_NONE, + ts); + + if (early_spktlen < 0) { + assert(ngtcp2_err_is_fatal((int)early_spktlen)); + return early_spktlen; + } + } + + conn->state = NGTCP2_CS_CLIENT_WAIT_HANDSHAKE; + + res = nwrite + early_spktlen; + + return res; + case NGTCP2_CS_CLIENT_WAIT_HANDSHAKE: + if (!conn_handshake_probe_left(conn) && conn_cwnd_is_zero(conn)) { + destlen = 0; + } else { + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED_HANDLED)) { + pending_early_datalen = conn_retry_early_payloadlen(conn); + if (pending_early_datalen) { + write_datalen = pending_early_datalen; + } + } + + nwrite = + conn_write_handshake_pkts(conn, pi, dest, destlen, write_datalen, ts); + if (nwrite < 0) { + return nwrite; + } + + res += nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + } + + if (!conn_is_handshake_completed(conn)) { + if (!(conn->flags & NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED)) { + nwrite = conn_retransmit_retry_early(conn, pi, dest, destlen, + NGTCP2_WRITE_PKT_FLAG_NONE, ts); + if (nwrite < 0) { + return nwrite; + } + + res += nwrite; + } + + if (res == 0) { + nwrite = conn_write_handshake_ack_pkts(conn, pi, dest, origlen, ts); + if (nwrite < 0) { + return nwrite; + } + res = nwrite; + } + + return res; + } + + if (!(conn->flags & NGTCP2_CONN_FLAG_TRANSPORT_PARAM_RECVED)) { + return NGTCP2_ERR_REQUIRED_TRANSPORT_PARAM; + } + + if ((conn->flags & NGTCP2_CONN_FLAG_EARLY_KEY_INSTALLED) && + !(conn->flags & NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED)) { + rv = conn_validate_early_transport_params_limits(conn); + if (rv != 0) { + return rv; + } + } + + /* Server might increase stream data limits. Extend it if we have + streams created for early data. */ + rv = conn_sync_stream_data_limit(conn); + if (rv != 0) { + return rv; + } + + conn->state = NGTCP2_CS_POST_HANDSHAKE; + + assert(conn->remote.transport_params); + + if (conn->remote.transport_params->preferred_address_present) { + assert(!ngtcp2_ringbuf_full(&conn->dcid.unused.rb)); + + paddr = &conn->remote.transport_params->preferred_address; + dcid = ngtcp2_ringbuf_push_back(&conn->dcid.unused.rb); + ngtcp2_dcid_init(dcid, 1, &paddr->cid, paddr->stateless_reset_token); + + rv = ngtcp2_gaptr_push(&conn->dcid.seqgap, 1, 1); + if (rv != 0) { + return (ngtcp2_ssize)rv; + } + } + + if (conn->remote.transport_params->stateless_reset_token_present) { + assert(conn->dcid.current.seq == 0); + assert(!(conn->dcid.current.flags & NGTCP2_DCID_FLAG_TOKEN_PRESENT)); + ngtcp2_dcid_set_token( + &conn->dcid.current, + conn->remote.transport_params->stateless_reset_token); + } + + rv = conn_call_activate_dcid(conn, &conn->dcid.current); + if (rv != 0) { + return rv; + } + + conn_process_early_rtb(conn); + + if (!conn->local.settings.no_pmtud) { + rv = conn_start_pmtud(conn); + if (rv != 0) { + return rv; + } + } + + return res; + case NGTCP2_CS_SERVER_INITIAL: + nwrite = + conn_write_handshake_pkts(conn, pi, dest, destlen, write_datalen, ts); + if (nwrite < 0) { + return nwrite; + } + + if (nwrite) { + conn->state = NGTCP2_CS_SERVER_WAIT_HANDSHAKE; + } + + return nwrite; + case NGTCP2_CS_SERVER_WAIT_HANDSHAKE: + if (conn_handshake_probe_left(conn) || !conn_cwnd_is_zero(conn)) { + nwrite = + conn_write_handshake_pkts(conn, pi, dest, destlen, write_datalen, ts); + if (nwrite < 0) { + return nwrite; + } + + res += nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + } + + if (res == 0) { + nwrite = conn_write_handshake_ack_pkts(conn, pi, dest, origlen, ts); + if (nwrite < 0) { + return nwrite; + } + + res += nwrite; + dest += nwrite; + origlen -= (size_t)nwrite; + } + + return res; + case NGTCP2_CS_CLOSING: + return NGTCP2_ERR_CLOSING; + case NGTCP2_CS_DRAINING: + return NGTCP2_ERR_DRAINING; + default: + return 0; + } +} + +/** + * @function + * + * `conn_client_write_handshake` writes client side handshake data and + * 0RTT packet. + * + * In order to send STREAM data in 0RTT packet, specify + * |vmsg|->stream. |vmsg|->stream.strm, |vmsg|->stream.fin, + * |vmsg|->stream.data, and |vmsg|->stream.datacnt are stream to which + * 0-RTT data is sent, whether it is a last data chunk in this stream, + * a vector of 0-RTT data, and its number of elements respectively. + * The amount of 0RTT data sent is assigned to + * *|vmsg|->stream.pdatalen. If no data is sent, -1 is assigned. + * Note that 0 length STREAM frame is allowed in QUIC, so 0 might be + * assigned to *|vmsg|->stream.pdatalen. + * + * This function returns 0 if it cannot write any frame because buffer + * is too small, or packet is congestion limited. Application should + * keep reading and wait for congestion window to grow. + * + * This function returns the number of bytes written to the buffer + * pointed by |dest| if it succeeds, or one of the following negative + * error codes: (TBD). + */ +static ngtcp2_ssize conn_client_write_handshake(ngtcp2_conn *conn, + ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + ngtcp2_vmsg *vmsg, + ngtcp2_tstamp ts) { + int send_stream = 0; + int send_datagram = 0; + ngtcp2_ssize spktlen, early_spktlen; + uint64_t datalen; + uint64_t write_datalen = 0; + uint8_t wflags = NGTCP2_WRITE_PKT_FLAG_NONE; + int ppe_pending = (conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING) != 0; + uint32_t version; + + assert(!conn->server); + + /* conn->early.ckm might be created in the first call of + conn_handshake(). Check it later. */ + if (vmsg) { + switch (vmsg->type) { + case NGTCP2_VMSG_TYPE_STREAM: + datalen = ngtcp2_vec_len(vmsg->stream.data, vmsg->stream.datacnt); + send_stream = + conn_retry_early_payloadlen(conn) == 0 && + /* 0 length STREAM frame is allowed */ + (datalen == 0 || + (datalen > 0 && + (vmsg->stream.strm->tx.max_offset - vmsg->stream.strm->tx.offset) && + (conn->tx.max_offset - conn->tx.offset))); + if (send_stream) { + write_datalen = + conn_enforce_flow_control(conn, vmsg->stream.strm, datalen); + write_datalen = + ngtcp2_min(write_datalen, NGTCP2_MIN_COALESCED_PAYLOADLEN); + write_datalen += NGTCP2_STREAM_OVERHEAD; + + if (vmsg->stream.flags & NGTCP2_WRITE_STREAM_FLAG_MORE) { + wflags |= NGTCP2_WRITE_PKT_FLAG_MORE; + } + } else { + vmsg = NULL; + } + break; + case NGTCP2_VMSG_TYPE_DATAGRAM: + datalen = ngtcp2_vec_len(vmsg->datagram.data, vmsg->datagram.datacnt); + send_datagram = conn_retry_early_payloadlen(conn) == 0; + if (send_datagram) { + write_datalen = datalen + NGTCP2_DATAGRAM_OVERHEAD; + + if (vmsg->datagram.flags & NGTCP2_WRITE_DATAGRAM_FLAG_MORE) { + wflags |= NGTCP2_WRITE_PKT_FLAG_MORE; + } + } else { + vmsg = NULL; + } + break; + } + } + + if (!ppe_pending) { + spktlen = conn_write_handshake(conn, pi, dest, destlen, write_datalen, ts); + + if (spktlen < 0) { + return spktlen; + } + + if ((conn->flags & NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED) || + !conn->early.ckm || (!send_stream && !send_datagram)) { + return spktlen; + } + + /* If spktlen > 0, we are making a compound packet. If Initial + packet is written, we have to pad bytes to 0-RTT packet. */ + version = conn->negotiated_version ? conn->negotiated_version + : conn->client_chosen_version; + if (spktlen > 0 && + ngtcp2_pkt_get_type_long(version, dest[0]) == NGTCP2_PKT_INITIAL) { + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + conn->pkt.require_padding = 1; + } else { + conn->pkt.require_padding = 0; + } + } else { + assert(!conn->pktns.crypto.rx.ckm); + assert(!conn->pktns.crypto.tx.ckm); + assert(conn->early.ckm); + + if (conn->pkt.require_padding) { + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + spktlen = conn->pkt.hs_spktlen; + } + + dest += spktlen; + destlen -= (size_t)spktlen; + + if (conn_cwnd_is_zero(conn)) { + return spktlen; + } + + early_spktlen = conn_write_pkt(conn, pi, dest, destlen, vmsg, NGTCP2_PKT_0RTT, + wflags, ts); + + if (early_spktlen < 0) { + switch (early_spktlen) { + case NGTCP2_ERR_STREAM_DATA_BLOCKED: + return spktlen; + case NGTCP2_ERR_WRITE_MORE: + conn->pkt.hs_spktlen = spktlen; + break; + } + return early_spktlen; + } + + return spktlen + early_spktlen; +} + +void ngtcp2_conn_handshake_completed(ngtcp2_conn *conn) { + conn->flags |= NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED; + if (conn->server) { + conn->flags |= NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED; + } +} + +int ngtcp2_conn_get_handshake_completed(ngtcp2_conn *conn) { + return conn_is_handshake_completed(conn) && + (conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED_HANDLED); +} + +int ngtcp2_conn_sched_ack(ngtcp2_conn *conn, ngtcp2_acktr *acktr, + int64_t pkt_num, int active_ack, ngtcp2_tstamp ts) { + int rv; + (void)conn; + + rv = ngtcp2_acktr_add(acktr, pkt_num, active_ack, ts); + if (rv != 0) { + assert(rv != NGTCP2_ERR_INVALID_ARGUMENT); + return rv; + } + + return 0; +} + +int ngtcp2_accept(ngtcp2_pkt_hd *dest, const uint8_t *pkt, size_t pktlen) { + ngtcp2_ssize nread; + ngtcp2_pkt_hd hd, *p; + + if (dest) { + p = dest; + } else { + p = &hd; + } + + if (pktlen == 0 || (pkt[0] & NGTCP2_HEADER_FORM_BIT) == 0) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + nread = ngtcp2_pkt_decode_hd_long(p, pkt, pktlen); + if (nread < 0) { + return (int)nread; + } + + switch (p->type) { + case NGTCP2_PKT_INITIAL: + break; + case NGTCP2_PKT_0RTT: + /* 0-RTT packet may arrive before Initial packet due to + re-ordering. ngtcp2 does not buffer 0RTT packet unless the + very first Initial packet is received or token is received. */ + return NGTCP2_ERR_RETRY; + default: + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + if (pktlen < NGTCP2_MAX_UDP_PAYLOAD_SIZE || + (p->tokenlen == 0 && p->dcid.datalen < NGTCP2_MIN_INITIAL_DCIDLEN)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + return 0; +} + +int ngtcp2_conn_install_initial_key( + ngtcp2_conn *conn, const ngtcp2_crypto_aead_ctx *rx_aead_ctx, + const uint8_t *rx_iv, const ngtcp2_crypto_cipher_ctx *rx_hp_ctx, + const ngtcp2_crypto_aead_ctx *tx_aead_ctx, const uint8_t *tx_iv, + const ngtcp2_crypto_cipher_ctx *tx_hp_ctx, size_t ivlen) { + ngtcp2_pktns *pktns = conn->in_pktns; + int rv; + + assert(ivlen >= 8); + assert(pktns); + + conn_call_delete_crypto_cipher_ctx(conn, &pktns->crypto.rx.hp_ctx); + pktns->crypto.rx.hp_ctx.native_handle = NULL; + + if (pktns->crypto.rx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &pktns->crypto.rx.ckm->aead_ctx); + ngtcp2_crypto_km_del(pktns->crypto.rx.ckm, conn->mem); + pktns->crypto.rx.ckm = NULL; + } + + conn_call_delete_crypto_cipher_ctx(conn, &pktns->crypto.tx.hp_ctx); + pktns->crypto.tx.hp_ctx.native_handle = NULL; + + if (pktns->crypto.tx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &pktns->crypto.tx.ckm->aead_ctx); + ngtcp2_crypto_km_del(pktns->crypto.tx.ckm, conn->mem); + pktns->crypto.tx.ckm = NULL; + } + + rv = ngtcp2_crypto_km_new(&pktns->crypto.rx.ckm, NULL, 0, NULL, rx_iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_crypto_km_new(&pktns->crypto.tx.ckm, NULL, 0, NULL, tx_iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + /* Take owner ship after we are sure that no failure occurs, so that + caller can delete these contexts on failure. */ + pktns->crypto.rx.ckm->aead_ctx = *rx_aead_ctx; + pktns->crypto.rx.hp_ctx = *rx_hp_ctx; + pktns->crypto.tx.ckm->aead_ctx = *tx_aead_ctx; + pktns->crypto.tx.hp_ctx = *tx_hp_ctx; + + return 0; +} + +int ngtcp2_conn_install_vneg_initial_key( + ngtcp2_conn *conn, uint32_t version, + const ngtcp2_crypto_aead_ctx *rx_aead_ctx, const uint8_t *rx_iv, + const ngtcp2_crypto_cipher_ctx *rx_hp_ctx, + const ngtcp2_crypto_aead_ctx *tx_aead_ctx, const uint8_t *tx_iv, + const ngtcp2_crypto_cipher_ctx *tx_hp_ctx, size_t ivlen) { + int rv; + + assert(ivlen >= 8); + + conn_call_delete_crypto_cipher_ctx(conn, &conn->vneg.rx.hp_ctx); + conn->vneg.rx.hp_ctx.native_handle = NULL; + + if (conn->vneg.rx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &conn->vneg.rx.ckm->aead_ctx); + ngtcp2_crypto_km_del(conn->vneg.rx.ckm, conn->mem); + conn->vneg.rx.ckm = NULL; + } + + conn_call_delete_crypto_cipher_ctx(conn, &conn->vneg.tx.hp_ctx); + conn->vneg.tx.hp_ctx.native_handle = NULL; + + if (conn->vneg.tx.ckm) { + conn_call_delete_crypto_aead_ctx(conn, &conn->vneg.tx.ckm->aead_ctx); + ngtcp2_crypto_km_del(conn->vneg.tx.ckm, conn->mem); + conn->vneg.tx.ckm = NULL; + } + + rv = ngtcp2_crypto_km_new(&conn->vneg.rx.ckm, NULL, 0, NULL, rx_iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_crypto_km_new(&conn->vneg.tx.ckm, NULL, 0, NULL, tx_iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + /* Take owner ship after we are sure that no failure occurs, so that + caller can delete these contexts on failure. */ + conn->vneg.rx.ckm->aead_ctx = *rx_aead_ctx; + conn->vneg.rx.hp_ctx = *rx_hp_ctx; + conn->vneg.tx.ckm->aead_ctx = *tx_aead_ctx; + conn->vneg.tx.hp_ctx = *tx_hp_ctx; + conn->vneg.version = version; + + return 0; +} + +int ngtcp2_conn_install_rx_handshake_key( + ngtcp2_conn *conn, const ngtcp2_crypto_aead_ctx *aead_ctx, + const uint8_t *iv, size_t ivlen, const ngtcp2_crypto_cipher_ctx *hp_ctx) { + ngtcp2_pktns *pktns = conn->hs_pktns; + int rv; + + assert(ivlen >= 8); + assert(pktns); + assert(!pktns->crypto.rx.hp_ctx.native_handle); + assert(!pktns->crypto.rx.ckm); + + rv = ngtcp2_crypto_km_new(&pktns->crypto.rx.ckm, NULL, 0, aead_ctx, iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + pktns->crypto.rx.hp_ctx = *hp_ctx; + + rv = conn_call_recv_rx_key(conn, NGTCP2_CRYPTO_LEVEL_HANDSHAKE); + if (rv != 0) { + ngtcp2_crypto_km_del(pktns->crypto.rx.ckm, conn->mem); + pktns->crypto.rx.ckm = NULL; + + memset(&pktns->crypto.rx.hp_ctx, 0, sizeof(pktns->crypto.rx.hp_ctx)); + + return rv; + } + + return 0; +} + +int ngtcp2_conn_install_tx_handshake_key( + ngtcp2_conn *conn, const ngtcp2_crypto_aead_ctx *aead_ctx, + const uint8_t *iv, size_t ivlen, const ngtcp2_crypto_cipher_ctx *hp_ctx) { + ngtcp2_pktns *pktns = conn->hs_pktns; + int rv; + + assert(ivlen >= 8); + assert(pktns); + assert(!pktns->crypto.tx.hp_ctx.native_handle); + assert(!pktns->crypto.tx.ckm); + + rv = ngtcp2_crypto_km_new(&pktns->crypto.tx.ckm, NULL, 0, aead_ctx, iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + pktns->crypto.tx.hp_ctx = *hp_ctx; + + if (conn->server) { + rv = ngtcp2_conn_commit_local_transport_params(conn); + if (rv != 0) { + return rv; + } + } + + rv = conn_call_recv_tx_key(conn, NGTCP2_CRYPTO_LEVEL_HANDSHAKE); + if (rv != 0) { + ngtcp2_crypto_km_del(pktns->crypto.tx.ckm, conn->mem); + pktns->crypto.tx.ckm = NULL; + + memset(&pktns->crypto.tx.hp_ctx, 0, sizeof(pktns->crypto.tx.hp_ctx)); + + return rv; + } + + return 0; +} + +int ngtcp2_conn_install_early_key(ngtcp2_conn *conn, + const ngtcp2_crypto_aead_ctx *aead_ctx, + const uint8_t *iv, size_t ivlen, + const ngtcp2_crypto_cipher_ctx *hp_ctx) { + int rv; + + assert(ivlen >= 8); + assert(!conn->early.hp_ctx.native_handle); + assert(!conn->early.ckm); + + rv = ngtcp2_crypto_km_new(&conn->early.ckm, NULL, 0, aead_ctx, iv, ivlen, + conn->mem); + if (rv != 0) { + return rv; + } + + conn->early.hp_ctx = *hp_ctx; + + conn->flags |= NGTCP2_CONN_FLAG_EARLY_KEY_INSTALLED; + + if (conn->server) { + rv = conn_call_recv_rx_key(conn, NGTCP2_CRYPTO_LEVEL_EARLY); + } else { + rv = conn_call_recv_tx_key(conn, NGTCP2_CRYPTO_LEVEL_EARLY); + } + if (rv != 0) { + ngtcp2_crypto_km_del(conn->early.ckm, conn->mem); + conn->early.ckm = NULL; + + memset(&conn->early.hp_ctx, 0, sizeof(conn->early.hp_ctx)); + + return rv; + } + + return 0; +} + +int ngtcp2_conn_install_rx_key(ngtcp2_conn *conn, const uint8_t *secret, + size_t secretlen, + const ngtcp2_crypto_aead_ctx *aead_ctx, + const uint8_t *iv, size_t ivlen, + const ngtcp2_crypto_cipher_ctx *hp_ctx) { + ngtcp2_pktns *pktns = &conn->pktns; + int rv; + + assert(ivlen >= 8); + assert(!pktns->crypto.rx.hp_ctx.native_handle); + assert(!pktns->crypto.rx.ckm); + + rv = ngtcp2_crypto_km_new(&pktns->crypto.rx.ckm, secret, secretlen, aead_ctx, + iv, ivlen, conn->mem); + if (rv != 0) { + return rv; + } + + pktns->crypto.rx.hp_ctx = *hp_ctx; + + if (!conn->server) { + if (conn->remote.pending_transport_params) { + ngtcp2_transport_params_del(conn->remote.transport_params, conn->mem); + + conn->remote.transport_params = conn->remote.pending_transport_params; + conn->remote.pending_transport_params = NULL; + conn_sync_stream_id_limit(conn); + conn->tx.max_offset = conn->remote.transport_params->initial_max_data; + } + + if (conn->early.ckm) { + conn_discard_early_key(conn); + } + } + + rv = conn_call_recv_rx_key(conn, NGTCP2_CRYPTO_LEVEL_APPLICATION); + if (rv != 0) { + ngtcp2_crypto_km_del(pktns->crypto.rx.ckm, conn->mem); + pktns->crypto.rx.ckm = NULL; + + memset(&pktns->crypto.rx.hp_ctx, 0, sizeof(pktns->crypto.rx.hp_ctx)); + + return rv; + } + + return 0; +} + +int ngtcp2_conn_install_tx_key(ngtcp2_conn *conn, const uint8_t *secret, + size_t secretlen, + const ngtcp2_crypto_aead_ctx *aead_ctx, + const uint8_t *iv, size_t ivlen, + const ngtcp2_crypto_cipher_ctx *hp_ctx) { + ngtcp2_pktns *pktns = &conn->pktns; + int rv; + + assert(ivlen >= 8); + assert(!pktns->crypto.tx.hp_ctx.native_handle); + assert(!pktns->crypto.tx.ckm); + + rv = ngtcp2_crypto_km_new(&pktns->crypto.tx.ckm, secret, secretlen, aead_ctx, + iv, ivlen, conn->mem); + if (rv != 0) { + return rv; + } + + pktns->crypto.tx.hp_ctx = *hp_ctx; + + if (conn->server) { + if (conn->remote.pending_transport_params) { + ngtcp2_transport_params_del(conn->remote.transport_params, conn->mem); + + conn->remote.transport_params = conn->remote.pending_transport_params; + conn->remote.pending_transport_params = NULL; + conn_sync_stream_id_limit(conn); + conn->tx.max_offset = conn->remote.transport_params->initial_max_data; + } + } else if (conn->early.ckm) { + conn_discard_early_key(conn); + } + + rv = conn_call_recv_tx_key(conn, NGTCP2_CRYPTO_LEVEL_APPLICATION); + if (rv != 0) { + ngtcp2_crypto_km_del(pktns->crypto.tx.ckm, conn->mem); + pktns->crypto.tx.ckm = NULL; + + memset(&pktns->crypto.tx.hp_ctx, 0, sizeof(pktns->crypto.tx.hp_ctx)); + + return rv; + } + + return 0; +} + +int ngtcp2_conn_initiate_key_update(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + ngtcp2_tstamp confirmed_ts = conn->crypto.key_update.confirmed_ts; + ngtcp2_duration pto = conn_compute_pto(conn, &conn->pktns); + + assert(conn->state == NGTCP2_CS_POST_HANDSHAKE); + + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED) || + (conn->flags & NGTCP2_CONN_FLAG_KEY_UPDATE_NOT_CONFIRMED) || + !conn->crypto.key_update.new_tx_ckm || + !conn->crypto.key_update.new_rx_ckm || + (confirmed_ts != UINT64_MAX && confirmed_ts + 3 * pto > ts)) { + return NGTCP2_ERR_INVALID_STATE; + } + + conn_rotate_keys(conn, NGTCP2_MAX_PKT_NUM, /* initiator = */ 1); + + return 0; +} + +/* + * conn_retire_stale_bound_dcid retires stale destination connection + * ID in conn->dcid.bound to keep some unused destination connection + * IDs available. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_retire_stale_bound_dcid(ngtcp2_conn *conn, + ngtcp2_duration timeout, + ngtcp2_tstamp ts) { + size_t i; + ngtcp2_dcid *dcid, *last; + int rv; + + for (i = 0; i < ngtcp2_ringbuf_len(&conn->dcid.bound.rb);) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, i); + + assert(dcid->cid.datalen); + + if (dcid->bound_ts + timeout > ts) { + ++i; + continue; + } + + rv = conn_retire_dcid_seq(conn, dcid->seq); + if (rv != 0) { + return rv; + } + + if (i == 0) { + ngtcp2_ringbuf_pop_front(&conn->dcid.bound.rb); + continue; + } + + if (i == ngtcp2_ringbuf_len(&conn->dcid.bound.rb) - 1) { + ngtcp2_ringbuf_pop_back(&conn->dcid.bound.rb); + break; + } + + last = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, + ngtcp2_ringbuf_len(&conn->dcid.bound.rb) - 1); + ngtcp2_dcid_copy(dcid, last); + ngtcp2_ringbuf_pop_back(&conn->dcid.bound.rb); + } + + return 0; +} + +ngtcp2_tstamp ngtcp2_conn_loss_detection_expiry(ngtcp2_conn *conn) { + return conn->cstat.loss_detection_timer; +} + +ngtcp2_tstamp ngtcp2_conn_internal_expiry(ngtcp2_conn *conn) { + ngtcp2_tstamp res = UINT64_MAX, t; + ngtcp2_duration pto = conn_compute_pto(conn, &conn->pktns); + ngtcp2_scid *scid; + ngtcp2_dcid *dcid; + size_t i, len; + + if (conn->pv) { + res = ngtcp2_pv_next_expiry(conn->pv); + } + + if (conn->pmtud) { + res = ngtcp2_min(res, conn->pmtud->expiry); + } + + if (!ngtcp2_pq_empty(&conn->scid.used)) { + scid = ngtcp2_struct_of(ngtcp2_pq_top(&conn->scid.used), ngtcp2_scid, pe); + if (scid->retired_ts != UINT64_MAX) { + t = scid->retired_ts + pto; + res = ngtcp2_min(res, t); + } + } + + if (ngtcp2_ringbuf_len(&conn->dcid.retired.rb)) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.retired.rb, 0); + t = dcid->retired_ts + pto; + res = ngtcp2_min(res, t); + } + + if (conn->dcid.current.cid.datalen) { + len = ngtcp2_ringbuf_len(&conn->dcid.bound.rb); + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.bound.rb, i); + + assert(dcid->cid.datalen); + assert(dcid->bound_ts != UINT64_MAX); + + t = dcid->bound_ts + 3 * pto; + res = ngtcp2_min(res, t); + } + } + + if (conn->server && conn->early.ckm && + conn->early.discard_started_ts != UINT64_MAX) { + t = conn->early.discard_started_ts + 3 * pto; + res = ngtcp2_min(res, t); + } + + return res; +} + +ngtcp2_tstamp ngtcp2_conn_ack_delay_expiry(ngtcp2_conn *conn) { + ngtcp2_acktr *acktr = &conn->pktns.acktr; + + if (!(acktr->flags & NGTCP2_ACKTR_FLAG_CANCEL_TIMER) && + acktr->first_unacked_ts != UINT64_MAX) { + return acktr->first_unacked_ts + conn_compute_ack_delay(conn); + } + return UINT64_MAX; +} + +static ngtcp2_tstamp conn_handshake_expiry(ngtcp2_conn *conn) { + if (conn_is_handshake_completed(conn) || + conn->local.settings.handshake_timeout == UINT64_MAX) { + return UINT64_MAX; + } + + return conn->local.settings.initial_ts + + conn->local.settings.handshake_timeout; +} + +ngtcp2_tstamp ngtcp2_conn_get_expiry(ngtcp2_conn *conn) { + ngtcp2_tstamp t1 = ngtcp2_conn_loss_detection_expiry(conn); + ngtcp2_tstamp t2 = ngtcp2_conn_ack_delay_expiry(conn); + ngtcp2_tstamp t3 = ngtcp2_conn_internal_expiry(conn); + ngtcp2_tstamp t4 = ngtcp2_conn_lost_pkt_expiry(conn); + ngtcp2_tstamp t5 = conn_keep_alive_expiry(conn); + ngtcp2_tstamp t6 = conn_handshake_expiry(conn); + ngtcp2_tstamp t7 = ngtcp2_conn_get_idle_expiry(conn); + ngtcp2_tstamp res = ngtcp2_min(t1, t2); + res = ngtcp2_min(res, t3); + res = ngtcp2_min(res, t4); + res = ngtcp2_min(res, t5); + res = ngtcp2_min(res, t6); + res = ngtcp2_min(res, t7); + return ngtcp2_min(res, conn->tx.pacing.next_ts); +} + +int ngtcp2_conn_handle_expiry(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + int rv; + ngtcp2_duration pto = conn_compute_pto(conn, &conn->pktns); + + assert(!(conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING)); + + if (ngtcp2_conn_get_idle_expiry(conn) <= ts) { + return NGTCP2_ERR_IDLE_CLOSE; + } + + ngtcp2_conn_cancel_expired_ack_delay_timer(conn, ts); + + conn_cancel_expired_keep_alive_timer(conn, ts); + + conn_cancel_expired_pkt_tx_timer(conn, ts); + + ngtcp2_conn_remove_lost_pkt(conn, ts); + + if (conn->pv) { + ngtcp2_pv_cancel_expired_timer(conn->pv, ts); + } + + if (conn->pmtud) { + ngtcp2_pmtud_handle_expiry(conn->pmtud, ts); + if (ngtcp2_pmtud_finished(conn->pmtud)) { + ngtcp2_conn_stop_pmtud(conn); + } + } + + if (ngtcp2_conn_loss_detection_expiry(conn) <= ts) { + rv = ngtcp2_conn_on_loss_detection_timer(conn, ts); + if (rv != 0) { + return rv; + } + } + + if (conn->dcid.current.cid.datalen) { + rv = conn_retire_stale_bound_dcid(conn, 3 * pto, ts); + if (rv != 0) { + return rv; + } + } + + rv = conn_remove_retired_connection_id(conn, pto, ts); + if (rv != 0) { + return rv; + } + + if (conn->server && conn->early.ckm && + conn->early.discard_started_ts != UINT64_MAX) { + if (conn->early.discard_started_ts + 3 * pto <= ts) { + conn_discard_early_key(conn); + } + } + + if (!conn_is_handshake_completed(conn) && + conn->local.settings.handshake_timeout != UINT64_MAX && + conn->local.settings.initial_ts + + conn->local.settings.handshake_timeout <= + ts) { + return NGTCP2_ERR_HANDSHAKE_TIMEOUT; + } + + return 0; +} + +static void acktr_cancel_expired_ack_delay_timer(ngtcp2_acktr *acktr, + ngtcp2_duration max_ack_delay, + ngtcp2_tstamp ts) { + if (!(acktr->flags & NGTCP2_ACKTR_FLAG_CANCEL_TIMER) && + acktr->first_unacked_ts != UINT64_MAX && + acktr->first_unacked_ts + max_ack_delay <= ts) { + acktr->flags |= NGTCP2_ACKTR_FLAG_CANCEL_TIMER; + } +} + +void ngtcp2_conn_cancel_expired_ack_delay_timer(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + ngtcp2_duration ack_delay = conn_compute_ack_delay(conn); + + if (conn->in_pktns) { + acktr_cancel_expired_ack_delay_timer(&conn->in_pktns->acktr, 0, ts); + } + if (conn->hs_pktns) { + acktr_cancel_expired_ack_delay_timer(&conn->hs_pktns->acktr, 0, ts); + } + acktr_cancel_expired_ack_delay_timer(&conn->pktns.acktr, ack_delay, ts); +} + +ngtcp2_tstamp ngtcp2_conn_lost_pkt_expiry(ngtcp2_conn *conn) { + ngtcp2_tstamp res = UINT64_MAX, ts; + + if (conn->in_pktns) { + ts = ngtcp2_rtb_lost_pkt_ts(&conn->in_pktns->rtb); + if (ts != UINT64_MAX) { + ts += conn_compute_pto(conn, conn->in_pktns); + res = ngtcp2_min(res, ts); + } + } + + if (conn->hs_pktns) { + ts = ngtcp2_rtb_lost_pkt_ts(&conn->hs_pktns->rtb); + if (ts != UINT64_MAX) { + ts += conn_compute_pto(conn, conn->hs_pktns); + res = ngtcp2_min(res, ts); + } + } + + ts = ngtcp2_rtb_lost_pkt_ts(&conn->pktns.rtb); + if (ts != UINT64_MAX) { + ts += conn_compute_pto(conn, &conn->pktns); + res = ngtcp2_min(res, ts); + } + + return res; +} + +void ngtcp2_conn_remove_lost_pkt(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + ngtcp2_duration pto; + + if (conn->in_pktns) { + pto = conn_compute_pto(conn, conn->in_pktns); + ngtcp2_rtb_remove_expired_lost_pkt(&conn->in_pktns->rtb, pto, ts); + } + if (conn->hs_pktns) { + pto = conn_compute_pto(conn, conn->hs_pktns); + ngtcp2_rtb_remove_expired_lost_pkt(&conn->hs_pktns->rtb, pto, ts); + } + pto = conn_compute_pto(conn, &conn->pktns); + ngtcp2_rtb_remove_expired_lost_pkt(&conn->pktns.rtb, pto, ts); +} + +/* + * select_preferred_version selects the most preferred version. + * |fallback_version| is chosen if no preference is made, or + * |preferred_versions| does not include any of |chosen_version| or + * |available_versions|. |chosen_version| is treated as an extra + * other version. + */ +static uint32_t select_preferred_version(const uint32_t *preferred_versions, + size_t preferred_versionslen, + uint32_t chosen_version, + const uint8_t *available_versions, + size_t available_versionslen, + uint32_t fallback_version) { + size_t i, j; + const uint8_t *p; + uint32_t v; + + if (!preferred_versionslen || + (!available_versionslen && chosen_version == fallback_version)) { + return fallback_version; + } + + for (i = 0; i < preferred_versionslen; ++i) { + if (preferred_versions[i] == chosen_version) { + return chosen_version; + } + for (j = 0, p = available_versions; j < available_versionslen; + j += sizeof(uint32_t)) { + p = ngtcp2_get_uint32(&v, p); + + if (preferred_versions[i] == v) { + return v; + } + } + } + + return fallback_version; +} + +/* + * conn_client_validate_transport_params validates |params| as client. + * |params| must be sent with Encrypted Extensions. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_TRANSPORT_PARAM + * params contains preferred address but server chose zero-length + * connection ID. + * NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE + * Validation against version negotiation parameters failed. + */ +static int +conn_client_validate_transport_params(ngtcp2_conn *conn, + const ngtcp2_transport_params *params) { + if (!ngtcp2_cid_eq(&conn->rcid, ¶ms->original_dcid)) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + if (conn->flags & NGTCP2_CONN_FLAG_RECV_RETRY) { + if (!params->retry_scid_present) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + if (!ngtcp2_cid_eq(&conn->retry_scid, ¶ms->retry_scid)) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + } else if (params->retry_scid_present) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + if (params->preferred_address_present && + conn->dcid.current.cid.datalen == 0) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + if (params->version_info_present) { + if (conn->negotiated_version != params->version_info.chosen_version) { + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + + assert(vneg_available_versions_includes(conn->vneg.available_versions, + conn->vneg.available_versionslen, + conn->negotiated_version)); + } else if (conn->client_chosen_version != conn->negotiated_version) { + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + + /* When client reacted upon Version Negotiation */ + if (conn->local.settings.original_version != conn->client_chosen_version) { + if (!params->version_info_present) { + assert(conn->client_chosen_version == conn->negotiated_version); + + /* QUIC v1 (and the supported draft versions) are treated + specially. If version_info is missing, no further validation + is necessary. + https://datatracker.ietf.org/doc/html/draft-ietf-quic-version-negotiation-10#section-8 + */ + if (conn->client_chosen_version == NGTCP2_PROTO_VER_V1 || + (NGTCP2_PROTO_VER_DRAFT_MIN <= conn->client_chosen_version && + conn->client_chosen_version <= NGTCP2_PROTO_VER_DRAFT_MAX)) { + return 0; + } + + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + + /* Server choose original version after Version Negotiation. + Draft does not say this particular case, but this smells like + misbehaved server because server should accept original_version + in the original connection. */ + if (conn->local.settings.original_version == + params->version_info.chosen_version) { + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + + /* Check version downgrade on incompatible version negotiation. */ + if (params->version_info.available_versionslen == 0) { + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + + if (conn->client_chosen_version != + select_preferred_version(conn->vneg.preferred_versions, + conn->vneg.preferred_versionslen, + params->version_info.chosen_version, + params->version_info.available_versions, + params->version_info.available_versionslen, + /* fallback_version = */ 0)) { + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + } + + return 0; +} + +uint32_t +ngtcp2_conn_server_negotiate_version(ngtcp2_conn *conn, + const ngtcp2_version_info *version_info) { + assert(conn->server); + assert(conn->client_chosen_version == version_info->chosen_version); + + return select_preferred_version( + conn->vneg.preferred_versions, conn->vneg.preferred_versionslen, + version_info->chosen_version, version_info->available_versions, + version_info->available_versionslen, version_info->chosen_version); +} + +int ngtcp2_conn_set_remote_transport_params( + ngtcp2_conn *conn, const ngtcp2_transport_params *params) { + int rv; + + /* We expect this function is called once per QUIC connection, but + GnuTLS server seems to call TLS extension callback twice if it + sends HelloRetryRequest. In practice, same QUIC transport + parameters are sent in the 2nd client flight, just returning 0 + would cause no harm. */ + if (conn->flags & NGTCP2_CONN_FLAG_TRANSPORT_PARAM_RECVED) { + return 0; + } + + /* Assume that ngtcp2_decode_transport_params sets default value if + active_connection_id_limit is omitted. */ + if (params->active_connection_id_limit < + NGTCP2_DEFAULT_ACTIVE_CONNECTION_ID_LIMIT) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + /* We assume that conn->dcid.current.cid is still the initial one. + This requires that transport parameter must be fed into + ngtcp2_conn as early as possible. */ + if (!ngtcp2_cid_eq(&conn->dcid.current.cid, ¶ms->initial_scid)) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + if (params->max_udp_payload_size < NGTCP2_MAX_UDP_PAYLOAD_SIZE) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + if (conn->server) { + if (params->version_info_present) { + if (!vneg_available_versions_includes( + params->version_info.available_versions, + params->version_info.available_versionslen, + params->version_info.chosen_version)) { + return NGTCP2_ERR_TRANSPORT_PARAM; + } + + if (params->version_info.chosen_version != conn->client_chosen_version) { + return NGTCP2_ERR_VERSION_NEGOTIATION_FAILURE; + } + + conn->negotiated_version = + ngtcp2_conn_server_negotiate_version(conn, ¶ms->version_info); + if (conn->negotiated_version != conn->client_chosen_version) { + rv = conn_call_version_negotiation(conn, conn->negotiated_version, + &conn->rcid); + if (rv != 0) { + return rv; + } + } + } else { + conn->negotiated_version = conn->client_chosen_version; + } + + conn->local.transport_params.version_info.chosen_version = + conn->negotiated_version; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "the negotiated version is 0x%08x", + conn->negotiated_version); + } else { + rv = conn_client_validate_transport_params(conn, params); + if (rv != 0) { + return rv; + } + } + + ngtcp2_log_remote_tp(&conn->log, + conn->server + ? NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO + : NGTCP2_TRANSPORT_PARAMS_TYPE_ENCRYPTED_EXTENSIONS, + params); + + ngtcp2_qlog_parameters_set_transport_params(&conn->qlog, params, conn->server, + NGTCP2_QLOG_SIDE_REMOTE); + + if ((conn->server && conn->pktns.crypto.tx.ckm) || + (!conn->server && conn->pktns.crypto.rx.ckm)) { + ngtcp2_transport_params_del(conn->remote.transport_params, conn->mem); + conn->remote.transport_params = NULL; + + rv = ngtcp2_transport_params_copy_new(&conn->remote.transport_params, + params, conn->mem); + if (rv != 0) { + return rv; + } + conn_sync_stream_id_limit(conn); + conn->tx.max_offset = conn->remote.transport_params->initial_max_data; + } else { + assert(!conn->remote.pending_transport_params); + + rv = ngtcp2_transport_params_copy_new( + &conn->remote.pending_transport_params, params, conn->mem); + if (rv != 0) { + return rv; + } + } + + conn->flags |= NGTCP2_CONN_FLAG_TRANSPORT_PARAM_RECVED; + + return 0; +} + +int ngtcp2_conn_decode_remote_transport_params(ngtcp2_conn *conn, + const uint8_t *data, + size_t datalen) { + ngtcp2_transport_params params; + int rv; + + rv = ngtcp2_decode_transport_params( + ¶ms, + conn->server ? NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO + : NGTCP2_TRANSPORT_PARAMS_TYPE_ENCRYPTED_EXTENSIONS, + data, datalen); + if (rv != 0) { + return rv; + } + + return ngtcp2_conn_set_remote_transport_params(conn, ¶ms); +} + +const ngtcp2_transport_params * +ngtcp2_conn_get_remote_transport_params(ngtcp2_conn *conn) { + if (conn->remote.pending_transport_params) { + return conn->remote.pending_transport_params; + } + + return conn->remote.transport_params; +} + +void ngtcp2_conn_set_early_remote_transport_params_versioned( + ngtcp2_conn *conn, int transport_params_version, + const ngtcp2_transport_params *params) { + ngtcp2_transport_params *p; + (void)transport_params_version; + + assert(!conn->server); + assert(!conn->remote.transport_params); + + /* Assume that all pointer fields in p are NULL */ + p = ngtcp2_mem_calloc(conn->mem, 1, sizeof(*p)); + + conn->remote.transport_params = p; + + p->initial_max_streams_bidi = params->initial_max_streams_bidi; + p->initial_max_streams_uni = params->initial_max_streams_uni; + p->initial_max_stream_data_bidi_local = + params->initial_max_stream_data_bidi_local; + p->initial_max_stream_data_bidi_remote = + params->initial_max_stream_data_bidi_remote; + p->initial_max_stream_data_uni = params->initial_max_stream_data_uni; + p->initial_max_data = params->initial_max_data; + p->active_connection_id_limit = + ngtcp2_max(NGTCP2_DEFAULT_ACTIVE_CONNECTION_ID_LIMIT, + params->active_connection_id_limit); + p->max_idle_timeout = params->max_idle_timeout; + if (!params->max_udp_payload_size) { + p->max_udp_payload_size = NGTCP2_DEFAULT_MAX_RECV_UDP_PAYLOAD_SIZE; + } else { + p->max_udp_payload_size = + ngtcp2_max(NGTCP2_MAX_UDP_PAYLOAD_SIZE, params->max_udp_payload_size); + } + p->disable_active_migration = params->disable_active_migration; + p->max_datagram_frame_size = params->max_datagram_frame_size; + + /* These parameters are treated specially. If server accepts early + data, it must not set values for these parameters that are + smaller than these remembered values. */ + conn->early.transport_params.initial_max_streams_bidi = + params->initial_max_streams_bidi; + conn->early.transport_params.initial_max_streams_uni = + params->initial_max_streams_uni; + conn->early.transport_params.initial_max_stream_data_bidi_local = + params->initial_max_stream_data_bidi_local; + conn->early.transport_params.initial_max_stream_data_bidi_remote = + params->initial_max_stream_data_bidi_remote; + conn->early.transport_params.initial_max_stream_data_uni = + params->initial_max_stream_data_uni; + conn->early.transport_params.initial_max_data = params->initial_max_data; + conn->early.transport_params.active_connection_id_limit = + params->active_connection_id_limit; + conn->early.transport_params.max_datagram_frame_size = + params->max_datagram_frame_size; + + conn_sync_stream_id_limit(conn); + + conn->tx.max_offset = p->initial_max_data; + + ngtcp2_qlog_parameters_set_transport_params(&conn->qlog, p, conn->server, + NGTCP2_QLOG_SIDE_REMOTE); +} + +int ngtcp2_conn_set_local_transport_params_versioned( + ngtcp2_conn *conn, int transport_params_version, + const ngtcp2_transport_params *params) { + (void)transport_params_version; + + assert(conn->server); + assert(params->active_connection_id_limit <= NGTCP2_MAX_DCID_POOL_SIZE); + + if (conn->hs_pktns == NULL || conn->hs_pktns->crypto.tx.ckm) { + return NGTCP2_ERR_INVALID_STATE; + } + + conn_set_local_transport_params(conn, params); + + return 0; +} + +int ngtcp2_conn_commit_local_transport_params(ngtcp2_conn *conn) { + const ngtcp2_mem *mem = conn->mem; + ngtcp2_transport_params *params = &conn->local.transport_params; + ngtcp2_scid *scident; + int rv; + + assert(1 == ngtcp2_ksl_len(&conn->scid.set)); + + if (params->active_connection_id_limit == 0) { + params->active_connection_id_limit = + NGTCP2_DEFAULT_ACTIVE_CONNECTION_ID_LIMIT; + } + + params->initial_scid = conn->oscid; + + if (conn->oscid.datalen == 0) { + params->preferred_address_present = 0; + } + + if (conn->server && params->preferred_address_present) { + scident = ngtcp2_mem_malloc(mem, sizeof(*scident)); + if (scident == NULL) { + return NGTCP2_ERR_NOMEM; + } + + ngtcp2_scid_init(scident, 1, ¶ms->preferred_address.cid); + + rv = ngtcp2_ksl_insert(&conn->scid.set, NULL, &scident->cid, scident); + if (rv != 0) { + ngtcp2_mem_free(mem, scident); + return rv; + } + + conn->scid.last_seq = 1; + } + + conn->rx.window = conn->rx.unsent_max_offset = conn->rx.max_offset = + params->initial_max_data; + conn->remote.bidi.unsent_max_streams = params->initial_max_streams_bidi; + conn->remote.bidi.max_streams = params->initial_max_streams_bidi; + conn->remote.uni.unsent_max_streams = params->initial_max_streams_uni; + conn->remote.uni.max_streams = params->initial_max_streams_uni; + + conn->flags |= NGTCP2_CONN_FLAG_LOCAL_TRANSPORT_PARAMS_COMMITTED; + + ngtcp2_qlog_parameters_set_transport_params(&conn->qlog, params, conn->server, + NGTCP2_QLOG_SIDE_LOCAL); + + return 0; +} + +const ngtcp2_transport_params * +ngtcp2_conn_get_local_transport_params(ngtcp2_conn *conn) { + return &conn->local.transport_params; +} + +ngtcp2_ssize ngtcp2_conn_encode_local_transport_params(ngtcp2_conn *conn, + uint8_t *dest, + size_t destlen) { + return ngtcp2_encode_transport_params( + dest, destlen, + conn->server ? NGTCP2_TRANSPORT_PARAMS_TYPE_ENCRYPTED_EXTENSIONS + : NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO, + &conn->local.transport_params); +} + +int ngtcp2_conn_open_bidi_stream(ngtcp2_conn *conn, int64_t *pstream_id, + void *stream_user_data) { + int rv; + ngtcp2_strm *strm; + + if (ngtcp2_conn_get_streams_bidi_left(conn) == 0) { + return NGTCP2_ERR_STREAM_ID_BLOCKED; + } + + strm = ngtcp2_objalloc_strm_get(&conn->strm_objalloc); + if (strm == NULL) { + return NGTCP2_ERR_NOMEM; + } + + rv = ngtcp2_conn_init_stream(conn, strm, conn->local.bidi.next_stream_id, + stream_user_data); + if (rv != 0) { + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm); + return rv; + } + + *pstream_id = conn->local.bidi.next_stream_id; + conn->local.bidi.next_stream_id += 4; + + return 0; +} + +int ngtcp2_conn_open_uni_stream(ngtcp2_conn *conn, int64_t *pstream_id, + void *stream_user_data) { + int rv; + ngtcp2_strm *strm; + + if (ngtcp2_conn_get_streams_uni_left(conn) == 0) { + return NGTCP2_ERR_STREAM_ID_BLOCKED; + } + + strm = ngtcp2_objalloc_strm_get(&conn->strm_objalloc); + if (strm == NULL) { + return NGTCP2_ERR_NOMEM; + } + + rv = ngtcp2_conn_init_stream(conn, strm, conn->local.uni.next_stream_id, + stream_user_data); + if (rv != 0) { + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm); + return rv; + } + ngtcp2_strm_shutdown(strm, NGTCP2_STRM_FLAG_SHUT_RD); + + *pstream_id = conn->local.uni.next_stream_id; + conn->local.uni.next_stream_id += 4; + + return 0; +} + +ngtcp2_strm *ngtcp2_conn_find_stream(ngtcp2_conn *conn, int64_t stream_id) { + return ngtcp2_map_find(&conn->strms, (uint64_t)stream_id); +} + +ngtcp2_ssize ngtcp2_conn_write_stream_versioned( + ngtcp2_conn *conn, ngtcp2_path *path, int pkt_info_version, + ngtcp2_pkt_info *pi, uint8_t *dest, size_t destlen, ngtcp2_ssize *pdatalen, + uint32_t flags, int64_t stream_id, const uint8_t *data, size_t datalen, + ngtcp2_tstamp ts) { + ngtcp2_vec datav; + + datav.len = datalen; + datav.base = (uint8_t *)data; + + return ngtcp2_conn_writev_stream_versioned(conn, path, pkt_info_version, pi, + dest, destlen, pdatalen, flags, + stream_id, &datav, 1, ts); +} + +static ngtcp2_ssize conn_write_vmsg_wrapper(ngtcp2_conn *conn, + ngtcp2_path *path, + int pkt_info_version, + ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, ngtcp2_vmsg *vmsg, + ngtcp2_tstamp ts) { + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_ssize nwrite; + int undersized; + + nwrite = ngtcp2_conn_write_vmsg(conn, path, pkt_info_version, pi, dest, + destlen, vmsg, ts); + if (nwrite < 0) { + return nwrite; + } + + if (cstat->bytes_in_flight >= cstat->cwnd) { + conn->rst.is_cwnd_limited = 1; + } + + if (vmsg == NULL && cstat->bytes_in_flight < cstat->cwnd && + conn->tx.strmq_nretrans == 0) { + if (conn->local.settings.no_tx_udp_payload_size_shaping) { + undersized = + (size_t)nwrite < conn->local.settings.max_tx_udp_payload_size; + } else { + undersized = (size_t)nwrite < conn->dcid.current.max_udp_payload_size; + } + + if (undersized) { + conn->rst.app_limited = conn->rst.delivered + cstat->bytes_in_flight; + + if (conn->rst.app_limited == 0) { + conn->rst.app_limited = cstat->max_tx_udp_payload_size; + } + } + } + + return nwrite; +} + +ngtcp2_ssize ngtcp2_conn_writev_stream_versioned( + ngtcp2_conn *conn, ngtcp2_path *path, int pkt_info_version, + ngtcp2_pkt_info *pi, uint8_t *dest, size_t destlen, ngtcp2_ssize *pdatalen, + uint32_t flags, int64_t stream_id, const ngtcp2_vec *datav, size_t datavcnt, + ngtcp2_tstamp ts) { + ngtcp2_vmsg vmsg, *pvmsg; + ngtcp2_strm *strm; + int64_t datalen; + + if (pdatalen) { + *pdatalen = -1; + } + + if (stream_id != -1) { + strm = ngtcp2_conn_find_stream(conn, stream_id); + if (strm == NULL) { + return NGTCP2_ERR_STREAM_NOT_FOUND; + } + + if (strm->flags & NGTCP2_STRM_FLAG_SHUT_WR) { + return NGTCP2_ERR_STREAM_SHUT_WR; + } + + datalen = ngtcp2_vec_len_varint(datav, datavcnt); + if (datalen == -1) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + if ((uint64_t)datalen > NGTCP2_MAX_VARINT - strm->tx.offset || + (uint64_t)datalen > NGTCP2_MAX_VARINT - conn->tx.offset) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + vmsg.type = NGTCP2_VMSG_TYPE_STREAM; + vmsg.stream.strm = strm; + vmsg.stream.flags = flags; + vmsg.stream.data = datav; + vmsg.stream.datacnt = datavcnt; + vmsg.stream.pdatalen = pdatalen; + + pvmsg = &vmsg; + } else { + pvmsg = NULL; + } + + return conn_write_vmsg_wrapper(conn, path, pkt_info_version, pi, dest, + destlen, pvmsg, ts); +} + +ngtcp2_ssize ngtcp2_conn_writev_datagram_versioned( + ngtcp2_conn *conn, ngtcp2_path *path, int pkt_info_version, + ngtcp2_pkt_info *pi, uint8_t *dest, size_t destlen, int *paccepted, + uint32_t flags, uint64_t dgram_id, const ngtcp2_vec *datav, size_t datavcnt, + ngtcp2_tstamp ts) { + ngtcp2_vmsg vmsg; + int64_t datalen; + + if (paccepted) { + *paccepted = 0; + } + + if (conn->remote.transport_params == NULL || + conn->remote.transport_params->max_datagram_frame_size == 0) { + return NGTCP2_ERR_INVALID_STATE; + } + + datalen = ngtcp2_vec_len_varint(datav, datavcnt); + if (datalen == -1 +#if UINT64_MAX > SIZE_MAX + || (uint64_t)datalen > SIZE_MAX +#endif /* UINT64_MAX > SIZE_MAX */ + ) { + return NGTCP2_ERR_INVALID_STATE; + } + + if (conn->remote.transport_params->max_datagram_frame_size < + ngtcp2_pkt_datagram_framelen((size_t)datalen)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + vmsg.type = NGTCP2_VMSG_TYPE_DATAGRAM; + vmsg.datagram.dgram_id = dgram_id; + vmsg.datagram.flags = flags; + vmsg.datagram.data = datav; + vmsg.datagram.datacnt = datavcnt; + vmsg.datagram.paccepted = paccepted; + + return conn_write_vmsg_wrapper(conn, path, pkt_info_version, pi, dest, + destlen, &vmsg, ts); +} + +ngtcp2_ssize ngtcp2_conn_write_vmsg(ngtcp2_conn *conn, ngtcp2_path *path, + int pkt_info_version, ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, + ngtcp2_vmsg *vmsg, ngtcp2_tstamp ts) { + ngtcp2_ssize nwrite; + size_t origlen; + size_t origdestlen = destlen; + int rv; + uint8_t wflags = NGTCP2_WRITE_PKT_FLAG_NONE; + int ppe_pending = (conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING) != 0; + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_ssize res = 0; + uint64_t server_tx_left; + uint64_t datalen; + uint64_t write_datalen = 0; + int64_t prev_in_pkt_num = -1; + ngtcp2_ksl_it it; + ngtcp2_rtb_entry *rtbent; + (void)pkt_info_version; + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + if (path) { + ngtcp2_path_copy(path, &conn->dcid.current.ps.path); + } + + origlen = destlen = + conn_shape_udp_payload(conn, &conn->dcid.current, destlen); + + if (!ppe_pending && pi) { + pi->ecn = NGTCP2_ECN_NOT_ECT; + } + + switch (conn->state) { + case NGTCP2_CS_CLIENT_INITIAL: + case NGTCP2_CS_CLIENT_WAIT_HANDSHAKE: + case NGTCP2_CS_CLIENT_TLS_HANDSHAKE_FAILED: + if (!conn_pacing_pkt_tx_allowed(conn, ts)) { + assert(!ppe_pending); + + return conn_write_handshake_ack_pkts(conn, pi, dest, origlen, ts); + } + + nwrite = conn_client_write_handshake(conn, pi, dest, destlen, vmsg, ts); + /* We might be unable to write a packet because of depletion of + congestion window budget, perhaps due to packet loss that + shrinks the window drastically. */ + if (nwrite <= 0) { + return nwrite; + } + if (conn->state != NGTCP2_CS_POST_HANDSHAKE) { + return nwrite; + } + + assert(nwrite); + assert(dest[0] & NGTCP2_HEADER_FORM_BIT); + assert(conn->negotiated_version); + + if (ngtcp2_pkt_get_type_long(conn->negotiated_version, dest[0]) == + NGTCP2_PKT_INITIAL) { + /* We have added padding already, but in that case, there is no + space left to write 1RTT packet. */ + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + + res = nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + /* Break here so that we can coalesces 1RTT packet. */ + break; + case NGTCP2_CS_SERVER_INITIAL: + case NGTCP2_CS_SERVER_WAIT_HANDSHAKE: + case NGTCP2_CS_SERVER_TLS_HANDSHAKE_FAILED: + if (!conn_pacing_pkt_tx_allowed(conn, ts)) { + assert(!ppe_pending); + + if (!(conn->dcid.current.flags & NGTCP2_DCID_FLAG_PATH_VALIDATED)) { + server_tx_left = conn_server_tx_left(conn, &conn->dcid.current); + if (server_tx_left == 0) { + return 0; + } + + origlen = (size_t)ngtcp2_min((uint64_t)origlen, server_tx_left); + } + + return conn_write_handshake_ack_pkts(conn, pi, dest, origlen, ts); + } + + if (!ppe_pending) { + if (!(conn->dcid.current.flags & NGTCP2_DCID_FLAG_PATH_VALIDATED)) { + server_tx_left = conn_server_tx_left(conn, &conn->dcid.current); + if (server_tx_left == 0) { + if (cstat->loss_detection_timer != UINT64_MAX) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_RCV, + "loss detection timer canceled due to amplification limit"); + cstat->loss_detection_timer = UINT64_MAX; + } + + return 0; + } + + destlen = (size_t)ngtcp2_min((uint64_t)destlen, server_tx_left); + } + + if (vmsg) { + switch (vmsg->type) { + case NGTCP2_VMSG_TYPE_STREAM: + datalen = ngtcp2_vec_len(vmsg->stream.data, vmsg->stream.datacnt); + if (datalen == 0 || (datalen > 0 && + (vmsg->stream.strm->tx.max_offset - + vmsg->stream.strm->tx.offset) && + (conn->tx.max_offset - conn->tx.offset))) { + write_datalen = + conn_enforce_flow_control(conn, vmsg->stream.strm, datalen); + write_datalen = + ngtcp2_min(write_datalen, NGTCP2_MIN_COALESCED_PAYLOADLEN); + write_datalen += NGTCP2_STREAM_OVERHEAD; + } + break; + case NGTCP2_VMSG_TYPE_DATAGRAM: + write_datalen = + ngtcp2_vec_len(vmsg->datagram.data, vmsg->datagram.datacnt) + + NGTCP2_DATAGRAM_OVERHEAD; + break; + default: + ngtcp2_unreachable(); + } + + if (conn->in_pktns && write_datalen > 0) { + it = ngtcp2_rtb_head(&conn->in_pktns->rtb); + if (!ngtcp2_ksl_it_end(&it)) { + rtbent = ngtcp2_ksl_it_get(&it); + prev_in_pkt_num = rtbent->hd.pkt_num; + } + } + } + + nwrite = conn_write_handshake(conn, pi, dest, destlen, write_datalen, ts); + if (nwrite < 0) { + return nwrite; + } + + res = nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + + if (conn->in_pktns && write_datalen > 0) { + it = ngtcp2_rtb_head(&conn->in_pktns->rtb); + if (!ngtcp2_ksl_it_end(&it)) { + rtbent = ngtcp2_ksl_it_get(&it); + if (rtbent->hd.pkt_num != prev_in_pkt_num && + (rtbent->flags & NGTCP2_RTB_ENTRY_FLAG_ACK_ELICITING)) { + /* We have added padding already, but in that case, there + is no space left to write 1RTT packet. */ + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + } + } + } + if (conn->state != NGTCP2_CS_POST_HANDSHAKE && + conn->pktns.crypto.tx.ckm == NULL) { + return res; + } + break; + case NGTCP2_CS_POST_HANDSHAKE: + if (!conn_pacing_pkt_tx_allowed(conn, ts)) { + assert(!ppe_pending); + + if (conn->server && + !(conn->dcid.current.flags & NGTCP2_DCID_FLAG_PATH_VALIDATED)) { + server_tx_left = conn_server_tx_left(conn, &conn->dcid.current); + if (server_tx_left == 0) { + return 0; + } + + origlen = (size_t)ngtcp2_min((uint64_t)origlen, server_tx_left); + } + + return conn_write_ack_pkt(conn, pi, dest, origlen, NGTCP2_PKT_1RTT, ts); + } + + break; + case NGTCP2_CS_CLOSING: + return NGTCP2_ERR_CLOSING; + case NGTCP2_CS_DRAINING: + return NGTCP2_ERR_DRAINING; + default: + return 0; + } + + assert(conn->pktns.crypto.tx.ckm); + + if (conn_check_pkt_num_exhausted(conn)) { + return NGTCP2_ERR_PKT_NUM_EXHAUSTED; + } + + if (vmsg) { + switch (vmsg->type) { + case NGTCP2_VMSG_TYPE_STREAM: + if (vmsg->stream.flags & NGTCP2_WRITE_STREAM_FLAG_MORE) { + wflags |= NGTCP2_WRITE_PKT_FLAG_MORE; + } + break; + case NGTCP2_VMSG_TYPE_DATAGRAM: + if (vmsg->datagram.flags & NGTCP2_WRITE_DATAGRAM_FLAG_MORE) { + wflags |= NGTCP2_WRITE_PKT_FLAG_MORE; + } + break; + default: + break; + } + } + + if (ppe_pending) { + res = conn->pkt.hs_spktlen; + conn->pkt.hs_spktlen = 0; + if (conn->pkt.require_padding) { + wflags |= NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + /* dest and destlen have already been adjusted in ppe in the first + run. They are adjusted for probe packet later. */ + nwrite = conn_write_pkt(conn, pi, dest, destlen, vmsg, NGTCP2_PKT_1RTT, + wflags, ts); + goto fin; + } else { + conn->pkt.require_padding = + (wflags & NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING); + + if (conn->state == NGTCP2_CS_POST_HANDSHAKE) { + rv = conn_prepare_key_update(conn, ts); + if (rv != 0) { + return rv; + } + } + + if (!conn->pktns.rtb.probe_pkt_left && conn_cwnd_is_zero(conn)) { + destlen = 0; + } else { + if (res == 0) { + nwrite = + conn_write_path_response(conn, path, pi, dest, origdestlen, ts); + if (nwrite) { + goto fin; + } + + if (conn->pv) { + nwrite = + conn_write_path_challenge(conn, path, pi, dest, origdestlen, ts); + if (nwrite) { + goto fin; + } + } + + if (conn->pmtud && + (conn->dcid.current.flags & NGTCP2_DCID_FLAG_PATH_VALIDATED) && + (!conn->hs_pktns || + ngtcp2_ksl_len(&conn->hs_pktns->crypto.tx.frq) == 0)) { + nwrite = conn_write_pmtud_probe(conn, pi, dest, origdestlen, ts); + if (nwrite) { + goto fin; + } + } + } + } + + if (conn->server && + !(conn->dcid.current.flags & NGTCP2_DCID_FLAG_PATH_VALIDATED)) { + server_tx_left = conn_server_tx_left(conn, &conn->dcid.current); + origlen = (size_t)ngtcp2_min((uint64_t)origlen, server_tx_left); + destlen = (size_t)ngtcp2_min((uint64_t)destlen, server_tx_left); + + if (server_tx_left == 0 && + conn->cstat.loss_detection_timer != UINT64_MAX) { + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_RCV, + "loss detection timer canceled due to amplification limit"); + conn->cstat.loss_detection_timer = UINT64_MAX; + } + } + } + + if (res == 0) { + if (conn_handshake_remnants_left(conn)) { + if (conn_handshake_probe_left(conn) || + /* Allow exceeding CWND if an Handshake packet needs to be + sent in order to avoid dead lock. In some situation, + typically for client, 1 RTT packets may occupy in-flight + bytes (e.g., some large requests and PMTUD), and + Handshake packet loss shrinks CWND, and we may get in the + situation that we are unable to send Handshake packet. */ + (conn->hs_pktns->rtb.num_pto_eliciting == 0 && + ngtcp2_ksl_len(&conn->hs_pktns->crypto.tx.frq))) { + destlen = origlen; + } + nwrite = conn_write_handshake_pkts(conn, pi, dest, destlen, + /* write_datalen = */ 0, ts); + if (nwrite < 0) { + return nwrite; + } + if (nwrite > 0) { + res = nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + } else if (destlen == 0) { + res = conn_write_handshake_ack_pkts(conn, pi, dest, origlen, ts); + if (res) { + return res; + } + } + } + } + + if (conn->pktns.rtb.probe_pkt_left) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_CON, + "transmit probe pkt left=%zu", + conn->pktns.rtb.probe_pkt_left); + + nwrite = conn_write_pkt(conn, pi, dest, destlen, vmsg, NGTCP2_PKT_1RTT, + wflags, ts); + + goto fin; + } + + nwrite = conn_write_pkt(conn, pi, dest, destlen, vmsg, NGTCP2_PKT_1RTT, + wflags, ts); + if (nwrite) { + assert(nwrite != NGTCP2_ERR_NOBUF); + goto fin; + } + + if (res == 0) { + nwrite = conn_write_ack_pkt(conn, pi, dest, origlen, NGTCP2_PKT_1RTT, ts); + } + +fin: + conn->pkt.hs_spktlen = 0; + + if (nwrite >= 0) { + res += nwrite; + return res; + } + /* NGTCP2_CONN_FLAG_PPE_PENDING is set in conn_write_pkt above. + ppe_pending cannot be used here. */ + if (conn->flags & NGTCP2_CONN_FLAG_PPE_PENDING) { + conn->pkt.hs_spktlen = res; + } + + return nwrite; +} + +static ngtcp2_ssize +conn_write_connection_close(ngtcp2_conn *conn, ngtcp2_pkt_info *pi, + uint8_t *dest, size_t destlen, uint8_t pkt_type, + uint64_t error_code, const uint8_t *reason, + size_t reasonlen, ngtcp2_tstamp ts) { + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + ngtcp2_ssize res = 0, nwrite; + ngtcp2_frame fr; + uint8_t flags = NGTCP2_WRITE_PKT_FLAG_NONE; + + fr.type = NGTCP2_FRAME_CONNECTION_CLOSE; + fr.connection_close.error_code = error_code; + fr.connection_close.frame_type = 0; + fr.connection_close.reasonlen = reasonlen; + fr.connection_close.reason = (uint8_t *)reason; + + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED) && + pkt_type != NGTCP2_PKT_INITIAL) { + if (in_pktns && conn->server) { + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_INITIAL, + NGTCP2_WRITE_PKT_FLAG_NONE, &conn->dcid.current.cid, &fr, + NGTCP2_RTB_ENTRY_FLAG_NONE, NULL, ts); + if (nwrite < 0) { + return nwrite; + } + + dest += nwrite; + destlen -= (size_t)nwrite; + res += nwrite; + } + + if (pkt_type != NGTCP2_PKT_HANDSHAKE && hs_pktns && + hs_pktns->crypto.tx.ckm) { + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_HANDSHAKE, + NGTCP2_WRITE_PKT_FLAG_NONE, &conn->dcid.current.cid, &fr, + NGTCP2_RTB_ENTRY_FLAG_NONE, NULL, ts); + if (nwrite < 0) { + return nwrite; + } + + dest += nwrite; + destlen -= (size_t)nwrite; + res += nwrite; + } + } + + if (!conn->server && pkt_type == NGTCP2_PKT_INITIAL) { + flags = NGTCP2_WRITE_PKT_FLAG_REQUIRE_PADDING; + } + + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, pkt_type, flags, &conn->dcid.current.cid, &fr, + NGTCP2_RTB_ENTRY_FLAG_NONE, NULL, ts); + + if (nwrite < 0) { + return nwrite; + } + + res += nwrite; + + if (res == 0) { + return NGTCP2_ERR_NOBUF; + } + + return res; +} + +ngtcp2_ssize ngtcp2_conn_write_connection_close_pkt( + ngtcp2_conn *conn, ngtcp2_path *path, ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, uint64_t error_code, const uint8_t *reason, + size_t reasonlen, ngtcp2_tstamp ts) { + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + uint8_t pkt_type; + ngtcp2_ssize nwrite; + uint64_t server_tx_left; + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + if (conn_check_pkt_num_exhausted(conn)) { + return NGTCP2_ERR_PKT_NUM_EXHAUSTED; + } + + switch (conn->state) { + case NGTCP2_CS_CLIENT_INITIAL: + return NGTCP2_ERR_INVALID_STATE; + case NGTCP2_CS_CLOSING: + case NGTCP2_CS_DRAINING: + return 0; + default: + break; + } + + if (path) { + ngtcp2_path_copy(path, &conn->dcid.current.ps.path); + } + + destlen = conn_shape_udp_payload(conn, &conn->dcid.current, destlen); + + if (pi) { + pi->ecn = NGTCP2_ECN_NOT_ECT; + } + + if (conn->server) { + server_tx_left = conn_server_tx_left(conn, &conn->dcid.current); + destlen = (size_t)ngtcp2_min((uint64_t)destlen, server_tx_left); + } + + if (conn->state == NGTCP2_CS_POST_HANDSHAKE || + (conn->server && conn->pktns.crypto.tx.ckm)) { + pkt_type = NGTCP2_PKT_1RTT; + } else if (hs_pktns && hs_pktns->crypto.tx.ckm) { + pkt_type = NGTCP2_PKT_HANDSHAKE; + } else if (in_pktns && in_pktns->crypto.tx.ckm) { + pkt_type = NGTCP2_PKT_INITIAL; + } else { + /* This branch is taken if server has not read any Initial packet + from client. */ + return NGTCP2_ERR_INVALID_STATE; + } + + nwrite = conn_write_connection_close(conn, pi, dest, destlen, pkt_type, + error_code, reason, reasonlen, ts); + if (nwrite < 0) { + return nwrite; + } + + conn->state = NGTCP2_CS_CLOSING; + + return nwrite; +} + +ngtcp2_ssize ngtcp2_conn_write_application_close_pkt( + ngtcp2_conn *conn, ngtcp2_path *path, ngtcp2_pkt_info *pi, uint8_t *dest, + size_t destlen, uint64_t app_error_code, const uint8_t *reason, + size_t reasonlen, ngtcp2_tstamp ts) { + ngtcp2_ssize nwrite; + ngtcp2_ssize res = 0; + ngtcp2_frame fr; + uint64_t server_tx_left; + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + if (conn_check_pkt_num_exhausted(conn)) { + return NGTCP2_ERR_PKT_NUM_EXHAUSTED; + } + + switch (conn->state) { + case NGTCP2_CS_CLIENT_INITIAL: + return NGTCP2_ERR_INVALID_STATE; + case NGTCP2_CS_CLOSING: + case NGTCP2_CS_DRAINING: + return 0; + default: + break; + } + + if (path) { + ngtcp2_path_copy(path, &conn->dcid.current.ps.path); + } + + destlen = conn_shape_udp_payload(conn, &conn->dcid.current, destlen); + + if (pi) { + pi->ecn = NGTCP2_ECN_NOT_ECT; + } + + if (conn->server) { + server_tx_left = conn_server_tx_left(conn, &conn->dcid.current); + destlen = (size_t)ngtcp2_min((uint64_t)destlen, server_tx_left); + } + + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED)) { + nwrite = conn_write_connection_close(conn, pi, dest, destlen, + conn->hs_pktns->crypto.tx.ckm + ? NGTCP2_PKT_HANDSHAKE + : NGTCP2_PKT_INITIAL, + NGTCP2_APPLICATION_ERROR, NULL, 0, ts); + if (nwrite < 0) { + return nwrite; + } + res = nwrite; + dest += nwrite; + destlen -= (size_t)nwrite; + } + + if (conn->state != NGTCP2_CS_POST_HANDSHAKE) { + assert(res); + + if (!conn->server || !conn->pktns.crypto.tx.ckm) { + return res; + } + } + + assert(conn->pktns.crypto.tx.ckm); + + fr.type = NGTCP2_FRAME_CONNECTION_CLOSE_APP; + fr.connection_close.error_code = app_error_code; + fr.connection_close.frame_type = 0; + fr.connection_close.reasonlen = reasonlen; + fr.connection_close.reason = (uint8_t *)reason; + + nwrite = ngtcp2_conn_write_single_frame_pkt( + conn, pi, dest, destlen, NGTCP2_PKT_1RTT, NGTCP2_WRITE_PKT_FLAG_NONE, + &conn->dcid.current.cid, &fr, NGTCP2_RTB_ENTRY_FLAG_NONE, NULL, ts); + + if (nwrite < 0) { + return nwrite; + } + + res += nwrite; + + if (res == 0) { + return NGTCP2_ERR_NOBUF; + } + + conn->state = NGTCP2_CS_CLOSING; + + return res; +} + +static void +connection_close_error_init(ngtcp2_connection_close_error *ccerr, + ngtcp2_connection_close_error_code_type type, + uint64_t error_code, const uint8_t *reason, + size_t reasonlen) { + ccerr->type = type; + ccerr->error_code = error_code; + ccerr->frame_type = 0; + ccerr->reason = (uint8_t *)reason; + ccerr->reasonlen = reasonlen; +} + +void ngtcp2_connection_close_error_default( + ngtcp2_connection_close_error *ccerr) { + connection_close_error_init(ccerr, + NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_TRANSPORT, + NGTCP2_NO_ERROR, NULL, 0); +} + +void ngtcp2_connection_close_error_set_transport_error( + ngtcp2_connection_close_error *ccerr, uint64_t error_code, + const uint8_t *reason, size_t reasonlen) { + connection_close_error_init(ccerr, + NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_TRANSPORT, + error_code, reason, reasonlen); +} + +void ngtcp2_connection_close_error_set_transport_error_liberr( + ngtcp2_connection_close_error *ccerr, int liberr, const uint8_t *reason, + size_t reasonlen) { + switch (liberr) { + case NGTCP2_ERR_RECV_VERSION_NEGOTIATION: + connection_close_error_init( + ccerr, + NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_TRANSPORT_VERSION_NEGOTIATION, + NGTCP2_NO_ERROR, reason, reasonlen); + + return; + case NGTCP2_ERR_IDLE_CLOSE: + connection_close_error_init( + ccerr, NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_TRANSPORT_IDLE_CLOSE, + NGTCP2_NO_ERROR, reason, reasonlen); + + return; + }; + + ngtcp2_connection_close_error_set_transport_error( + ccerr, ngtcp2_err_infer_quic_transport_error_code(liberr), reason, + reasonlen); +} + +void ngtcp2_connection_close_error_set_transport_error_tls_alert( + ngtcp2_connection_close_error *ccerr, uint8_t tls_alert, + const uint8_t *reason, size_t reasonlen) { + ngtcp2_connection_close_error_set_transport_error( + ccerr, NGTCP2_CRYPTO_ERROR | tls_alert, reason, reasonlen); +} + +void ngtcp2_connection_close_error_set_application_error( + ngtcp2_connection_close_error *ccerr, uint64_t error_code, + const uint8_t *reason, size_t reasonlen) { + connection_close_error_init( + ccerr, NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_APPLICATION, error_code, + reason, reasonlen); +} + +ngtcp2_ssize ngtcp2_conn_write_connection_close_versioned( + ngtcp2_conn *conn, ngtcp2_path *path, int pkt_info_version, + ngtcp2_pkt_info *pi, uint8_t *dest, size_t destlen, + const ngtcp2_connection_close_error *ccerr, ngtcp2_tstamp ts) { + (void)pkt_info_version; + + switch (ccerr->type) { + case NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_TRANSPORT: + return ngtcp2_conn_write_connection_close_pkt( + conn, path, pi, dest, destlen, ccerr->error_code, ccerr->reason, + ccerr->reasonlen, ts); + case NGTCP2_CONNECTION_CLOSE_ERROR_CODE_TYPE_APPLICATION: + return ngtcp2_conn_write_application_close_pkt( + conn, path, pi, dest, destlen, ccerr->error_code, ccerr->reason, + ccerr->reasonlen, ts); + default: + return 0; + } +} + +int ngtcp2_conn_is_in_closing_period(ngtcp2_conn *conn) { + return conn->state == NGTCP2_CS_CLOSING; +} + +int ngtcp2_conn_is_in_draining_period(ngtcp2_conn *conn) { + return conn->state == NGTCP2_CS_DRAINING; +} + +int ngtcp2_conn_close_stream(ngtcp2_conn *conn, ngtcp2_strm *strm) { + int rv; + + rv = conn_call_stream_close(conn, strm); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_map_remove(&conn->strms, (ngtcp2_map_key_type)strm->stream_id); + if (rv != 0) { + assert(rv != NGTCP2_ERR_INVALID_ARGUMENT); + return rv; + } + + if (ngtcp2_strm_is_tx_queued(strm)) { + ngtcp2_pq_remove(&conn->tx.strmq, &strm->pe); + if (!ngtcp2_strm_streamfrq_empty(strm)) { + assert(conn->tx.strmq_nretrans); + --conn->tx.strmq_nretrans; + } + } + + ngtcp2_strm_free(strm); + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm); + + return 0; +} + +int ngtcp2_conn_close_stream_if_shut_rdwr(ngtcp2_conn *conn, + ngtcp2_strm *strm) { + if ((strm->flags & NGTCP2_STRM_FLAG_SHUT_RDWR) == + NGTCP2_STRM_FLAG_SHUT_RDWR && + ((strm->flags & NGTCP2_STRM_FLAG_RECV_RST) || + ngtcp2_strm_rx_offset(strm) == strm->rx.last_offset) && + (((strm->flags & NGTCP2_STRM_FLAG_SENT_RST) && + (strm->flags & NGTCP2_STRM_FLAG_RST_ACKED)) || + ngtcp2_strm_is_all_tx_data_fin_acked(strm))) { + return ngtcp2_conn_close_stream(conn, strm); + } + return 0; +} + +/* + * conn_shutdown_stream_write closes send stream with error code + * |app_error_code|. RESET_STREAM frame is scheduled. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_shutdown_stream_write(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t app_error_code) { + ngtcp2_strm_set_app_error_code(strm, app_error_code); + + if ((strm->flags & NGTCP2_STRM_FLAG_SENT_RST) || + ngtcp2_strm_is_all_tx_data_fin_acked(strm)) { + return 0; + } + + /* Set this flag so that we don't accidentally send DATA to this + stream. */ + strm->flags |= NGTCP2_STRM_FLAG_SHUT_WR | NGTCP2_STRM_FLAG_SENT_RST; + + ngtcp2_strm_streamfrq_clear(strm); + + return conn_reset_stream(conn, strm, app_error_code); +} + +/* + * conn_shutdown_stream_read closes read stream with error code + * |app_error_code|. STOP_SENDING frame is scheduled. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_shutdown_stream_read(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t app_error_code) { + ngtcp2_strm_set_app_error_code(strm, app_error_code); + + if (strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING) { + return 0; + } + if ((strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) && + ngtcp2_strm_rx_offset(strm) == strm->rx.last_offset) { + return 0; + } + + /* Extend connection flow control window for the amount of data + which are not passed to application. */ + if (!(strm->flags & + (NGTCP2_STRM_FLAG_STOP_SENDING | NGTCP2_STRM_FLAG_RECV_RST))) { + ngtcp2_conn_extend_max_offset(conn, strm->rx.last_offset - + ngtcp2_strm_rx_offset(strm)); + } + + strm->flags |= NGTCP2_STRM_FLAG_STOP_SENDING; + + return conn_stop_sending(conn, strm, app_error_code); +} + +int ngtcp2_conn_shutdown_stream(ngtcp2_conn *conn, int64_t stream_id, + uint64_t app_error_code) { + int rv; + ngtcp2_strm *strm; + + strm = ngtcp2_conn_find_stream(conn, stream_id); + if (strm == NULL) { + return 0; + } + + if (bidi_stream(stream_id) || !conn_local_stream(conn, stream_id)) { + rv = conn_shutdown_stream_read(conn, strm, app_error_code); + if (rv != 0) { + return rv; + } + } + + if (bidi_stream(stream_id) || conn_local_stream(conn, stream_id)) { + rv = conn_shutdown_stream_write(conn, strm, app_error_code); + if (rv != 0) { + return rv; + } + } + + return 0; +} + +int ngtcp2_conn_shutdown_stream_write(ngtcp2_conn *conn, int64_t stream_id, + uint64_t app_error_code) { + ngtcp2_strm *strm; + + if (!bidi_stream(stream_id) && !conn_local_stream(conn, stream_id)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + strm = ngtcp2_conn_find_stream(conn, stream_id); + if (strm == NULL) { + return 0; + } + + return conn_shutdown_stream_write(conn, strm, app_error_code); +} + +int ngtcp2_conn_shutdown_stream_read(ngtcp2_conn *conn, int64_t stream_id, + uint64_t app_error_code) { + ngtcp2_strm *strm; + + if (!bidi_stream(stream_id) && conn_local_stream(conn, stream_id)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + strm = ngtcp2_conn_find_stream(conn, stream_id); + if (strm == NULL) { + return 0; + } + + return conn_shutdown_stream_read(conn, strm, app_error_code); +} + +/* + * conn_extend_max_stream_offset extends stream level flow control + * window by |datalen| of the stream denoted by |strm|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + */ +static int conn_extend_max_stream_offset(ngtcp2_conn *conn, ngtcp2_strm *strm, + uint64_t datalen) { + ngtcp2_strm *top; + + if (datalen > NGTCP2_MAX_VARINT || + strm->rx.unsent_max_offset > NGTCP2_MAX_VARINT - datalen) { + strm->rx.unsent_max_offset = NGTCP2_MAX_VARINT; + } else { + strm->rx.unsent_max_offset += datalen; + } + + if (!(strm->flags & + (NGTCP2_STRM_FLAG_SHUT_RD | NGTCP2_STRM_FLAG_STOP_SENDING)) && + !ngtcp2_strm_is_tx_queued(strm) && + conn_should_send_max_stream_data(conn, strm)) { + if (!ngtcp2_pq_empty(&conn->tx.strmq)) { + top = ngtcp2_conn_tx_strmq_top(conn); + strm->cycle = top->cycle; + } + strm->cycle = conn_tx_strmq_first_cycle(conn); + return ngtcp2_conn_tx_strmq_push(conn, strm); + } + + return 0; +} + +int ngtcp2_conn_extend_max_stream_offset(ngtcp2_conn *conn, int64_t stream_id, + uint64_t datalen) { + ngtcp2_strm *strm; + + strm = ngtcp2_conn_find_stream(conn, stream_id); + if (strm == NULL) { + return 0; + } + + return conn_extend_max_stream_offset(conn, strm, datalen); +} + +void ngtcp2_conn_extend_max_offset(ngtcp2_conn *conn, uint64_t datalen) { + if (NGTCP2_MAX_VARINT < datalen || + conn->rx.unsent_max_offset > NGTCP2_MAX_VARINT - datalen) { + conn->rx.unsent_max_offset = NGTCP2_MAX_VARINT; + return; + } + + conn->rx.unsent_max_offset += datalen; +} + +void ngtcp2_conn_extend_max_streams_bidi(ngtcp2_conn *conn, size_t n) { + handle_max_remote_streams_extension(&conn->remote.bidi.unsent_max_streams, n); +} + +void ngtcp2_conn_extend_max_streams_uni(ngtcp2_conn *conn, size_t n) { + handle_max_remote_streams_extension(&conn->remote.uni.unsent_max_streams, n); +} + +const ngtcp2_cid *ngtcp2_conn_get_dcid(ngtcp2_conn *conn) { + return &conn->dcid.current.cid; +} + +const ngtcp2_cid *ngtcp2_conn_get_client_initial_dcid(ngtcp2_conn *conn) { + return &conn->rcid; +} + +uint32_t ngtcp2_conn_get_client_chosen_version(ngtcp2_conn *conn) { + return conn->client_chosen_version; +} + +uint32_t ngtcp2_conn_get_negotiated_version(ngtcp2_conn *conn) { + return conn->negotiated_version; +} + +static int delete_strms_pq_each(void *data, void *ptr) { + ngtcp2_conn *conn = ptr; + ngtcp2_strm *s = data; + + if (ngtcp2_strm_is_tx_queued(s)) { + ngtcp2_pq_remove(&conn->tx.strmq, &s->pe); + if (!ngtcp2_strm_streamfrq_empty(s)) { + assert(conn->tx.strmq_nretrans); + --conn->tx.strmq_nretrans; + } + } + + ngtcp2_strm_free(s); + ngtcp2_objalloc_strm_release(&conn->strm_objalloc, s); + + return 0; +} + +/* + * conn_discard_early_data_state discards any connection states which + * are altered by any operations during early data transfer. + */ +static void conn_discard_early_data_state(ngtcp2_conn *conn) { + ngtcp2_frame_chain **pfrc, *frc; + + ngtcp2_rtb_remove_early_data(&conn->pktns.rtb, &conn->cstat); + + ngtcp2_map_each_free(&conn->strms, delete_strms_pq_each, conn); + ngtcp2_map_clear(&conn->strms); + + conn->tx.offset = 0; + + conn->rx.unsent_max_offset = conn->rx.max_offset = + conn->local.transport_params.initial_max_data; + + conn->remote.bidi.unsent_max_streams = conn->remote.bidi.max_streams = + conn->local.transport_params.initial_max_streams_bidi; + + conn->remote.uni.unsent_max_streams = conn->remote.uni.max_streams = + conn->local.transport_params.initial_max_streams_uni; + + if (conn->server) { + conn->local.bidi.next_stream_id = 1; + conn->local.uni.next_stream_id = 3; + } else { + conn->local.bidi.next_stream_id = 0; + conn->local.uni.next_stream_id = 2; + } + + for (pfrc = &conn->pktns.tx.frq; *pfrc;) { + frc = *pfrc; + *pfrc = (*pfrc)->next; + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + } +} + +int ngtcp2_conn_early_data_rejected(ngtcp2_conn *conn) { + if (conn->flags & NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED) { + return 0; + } + + conn->flags |= NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED; + + conn_discard_early_data_state(conn); + + if (conn->callbacks.early_data_rejected) { + return conn->callbacks.early_data_rejected(conn, conn->user_data); + } + + return 0; +} + +int ngtcp2_conn_get_early_data_rejected(ngtcp2_conn *conn) { + return (conn->flags & NGTCP2_CONN_FLAG_EARLY_DATA_REJECTED) != 0; +} + +int ngtcp2_conn_update_rtt(ngtcp2_conn *conn, ngtcp2_duration rtt, + ngtcp2_duration ack_delay, ngtcp2_tstamp ts) { + ngtcp2_conn_stat *cstat = &conn->cstat; + + if (cstat->min_rtt == UINT64_MAX) { + cstat->latest_rtt = rtt; + cstat->min_rtt = rtt; + cstat->smoothed_rtt = rtt; + cstat->rttvar = rtt / 2; + cstat->first_rtt_sample_ts = ts; + } else { + if (conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED) { + assert(conn->remote.transport_params); + + ack_delay = + ngtcp2_min(ack_delay, conn->remote.transport_params->max_ack_delay); + } else if (ack_delay > 0 && rtt >= cstat->min_rtt && + rtt < cstat->min_rtt + ack_delay) { + /* Ignore RTT sample if adjusting ack_delay causes the sample + less than min_rtt before handshake confirmation. */ + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_RCV, + "ignore rtt sample because ack_delay is too large latest_rtt=%" PRIu64 + " min_rtt=%" PRIu64 " ack_delay=%" PRIu64, + rtt / NGTCP2_MILLISECONDS, cstat->min_rtt / NGTCP2_MILLISECONDS, + ack_delay / NGTCP2_MILLISECONDS); + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + cstat->latest_rtt = rtt; + cstat->min_rtt = ngtcp2_min(cstat->min_rtt, rtt); + + if (rtt >= cstat->min_rtt + ack_delay) { + rtt -= ack_delay; + } + + cstat->rttvar = (cstat->rttvar * 3 + (cstat->smoothed_rtt < rtt + ? rtt - cstat->smoothed_rtt + : cstat->smoothed_rtt - rtt)) / + 4; + cstat->smoothed_rtt = (cstat->smoothed_rtt * 7 + rtt) / 8; + } + + ngtcp2_log_info( + &conn->log, NGTCP2_LOG_EVENT_RCV, + "latest_rtt=%" PRIu64 " min_rtt=%" PRIu64 " smoothed_rtt=%" PRIu64 + " rttvar=%" PRIu64 " ack_delay=%" PRIu64, + cstat->latest_rtt / NGTCP2_MILLISECONDS, + cstat->min_rtt / NGTCP2_MILLISECONDS, + cstat->smoothed_rtt / NGTCP2_MILLISECONDS, + cstat->rttvar / NGTCP2_MILLISECONDS, ack_delay / NGTCP2_MILLISECONDS); + + return 0; +} + +void ngtcp2_conn_get_conn_stat_versioned(ngtcp2_conn *conn, + int conn_stat_version, + ngtcp2_conn_stat *cstat) { + (void)conn_stat_version; + + *cstat = conn->cstat; +} + +static void conn_get_loss_time_and_pktns(ngtcp2_conn *conn, + ngtcp2_tstamp *ploss_time, + ngtcp2_pktns **ppktns) { + ngtcp2_pktns *const ns[] = {conn->hs_pktns, &conn->pktns}; + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_duration *loss_time = cstat->loss_time + 1; + ngtcp2_tstamp earliest_loss_time = cstat->loss_time[NGTCP2_PKTNS_ID_INITIAL]; + ngtcp2_pktns *pktns = conn->in_pktns; + size_t i; + + for (i = 0; i < ngtcp2_arraylen(ns); ++i) { + if (ns[i] == NULL || loss_time[i] >= earliest_loss_time) { + continue; + } + + earliest_loss_time = loss_time[i]; + pktns = ns[i]; + } + + if (ploss_time) { + *ploss_time = earliest_loss_time; + } + if (ppktns) { + *ppktns = pktns; + } +} + +static ngtcp2_tstamp conn_get_earliest_pto_expiry(ngtcp2_conn *conn, + ngtcp2_tstamp ts) { + ngtcp2_pktns *ns[] = {conn->in_pktns, conn->hs_pktns, &conn->pktns}; + size_t i; + ngtcp2_tstamp earliest_ts = UINT64_MAX, t; + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_tstamp *times = cstat->last_tx_pkt_ts; + ngtcp2_duration duration = + compute_pto(cstat->smoothed_rtt, cstat->rttvar, /* max_ack_delay = */ 0) * + (1ULL << cstat->pto_count); + + for (i = NGTCP2_PKTNS_ID_INITIAL; i < NGTCP2_PKTNS_ID_MAX; ++i) { + if (ns[i] == NULL || ns[i]->rtb.num_pto_eliciting == 0 || + (times[i] == UINT64_MAX || + (i == NGTCP2_PKTNS_ID_APPLICATION && + !(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED)))) { + continue; + } + + t = times[i] + duration; + + if (i == NGTCP2_PKTNS_ID_APPLICATION) { + assert(conn->remote.transport_params); + t += conn->remote.transport_params->max_ack_delay * + (1ULL << cstat->pto_count); + } + + if (t < earliest_ts) { + earliest_ts = t; + } + } + + if (earliest_ts == UINT64_MAX) { + return ts + duration; + } + + return earliest_ts; +} + +void ngtcp2_conn_set_loss_detection_timer(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + ngtcp2_conn_stat *cstat = &conn->cstat; + ngtcp2_duration timeout; + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + ngtcp2_pktns *pktns = &conn->pktns; + ngtcp2_tstamp earliest_loss_time; + + conn_get_loss_time_and_pktns(conn, &earliest_loss_time, NULL); + + if (earliest_loss_time != UINT64_MAX) { + cstat->loss_detection_timer = earliest_loss_time; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_RCV, + "loss_detection_timer=%" PRIu64 " nonzero crypto loss time", + cstat->loss_detection_timer); + return; + } + + if ((!in_pktns || in_pktns->rtb.num_pto_eliciting == 0) && + (!hs_pktns || hs_pktns->rtb.num_pto_eliciting == 0) && + (pktns->rtb.num_pto_eliciting == 0 || + !(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED)) && + (conn->server || + (conn->flags & (NGTCP2_CONN_FLAG_SERVER_ADDR_VERIFIED | + NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED)))) { + if (cstat->loss_detection_timer != UINT64_MAX) { + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_RCV, + "loss detection timer canceled"); + cstat->loss_detection_timer = UINT64_MAX; + cstat->pto_count = 0; + } + return; + } + + cstat->loss_detection_timer = conn_get_earliest_pto_expiry(conn, ts); + + timeout = + cstat->loss_detection_timer > ts ? cstat->loss_detection_timer - ts : 0; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_RCV, + "loss_detection_timer=%" PRIu64 " timeout=%" PRIu64, + cstat->loss_detection_timer, timeout / NGTCP2_MILLISECONDS); +} + +int ngtcp2_conn_on_loss_detection_timer(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + ngtcp2_conn_stat *cstat = &conn->cstat; + int rv; + ngtcp2_pktns *in_pktns = conn->in_pktns; + ngtcp2_pktns *hs_pktns = conn->hs_pktns; + ngtcp2_tstamp earliest_loss_time; + ngtcp2_pktns *loss_pktns = NULL; + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + switch (conn->state) { + case NGTCP2_CS_CLOSING: + case NGTCP2_CS_DRAINING: + cstat->loss_detection_timer = UINT64_MAX; + cstat->pto_count = 0; + return 0; + default: + break; + } + + if (cstat->loss_detection_timer == UINT64_MAX) { + return 0; + } + + conn_get_loss_time_and_pktns(conn, &earliest_loss_time, &loss_pktns); + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_RCV, + "loss detection timer fired"); + + if (earliest_loss_time != UINT64_MAX) { + assert(loss_pktns); + + rv = ngtcp2_conn_detect_lost_pkt(conn, loss_pktns, cstat, ts); + if (rv != 0) { + return rv; + } + ngtcp2_conn_set_loss_detection_timer(conn, ts); + return 0; + } + + if (!conn->server && !conn_is_handshake_completed(conn)) { + if (hs_pktns->crypto.tx.ckm) { + hs_pktns->rtb.probe_pkt_left = 1; + } else { + in_pktns->rtb.probe_pkt_left = 1; + } + } else { + if (in_pktns && in_pktns->rtb.num_pto_eliciting) { + in_pktns->rtb.probe_pkt_left = 1; + + assert(hs_pktns); + + if (conn->server && hs_pktns->rtb.num_pto_eliciting) { + /* let server coalesce packets */ + hs_pktns->rtb.probe_pkt_left = 1; + } + } else if (hs_pktns && hs_pktns->rtb.num_pto_eliciting) { + hs_pktns->rtb.probe_pkt_left = 1; + } else { + conn->pktns.rtb.probe_pkt_left = 2; + } + } + + ++cstat->pto_count; + + ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_RCV, "pto_count=%zu", + cstat->pto_count); + + ngtcp2_conn_set_loss_detection_timer(conn, ts); + + return 0; +} + +static int conn_buffer_crypto_data(ngtcp2_conn *conn, const uint8_t **pdata, + ngtcp2_pktns *pktns, const uint8_t *data, + size_t datalen) { + int rv; + ngtcp2_buf_chain **pbufchain = &pktns->crypto.tx.data; + + if (*pbufchain) { + for (; (*pbufchain)->next; pbufchain = &(*pbufchain)->next) + ; + + if (ngtcp2_buf_left(&(*pbufchain)->buf) < datalen) { + pbufchain = &(*pbufchain)->next; + } + } + + if (!*pbufchain) { + rv = ngtcp2_buf_chain_new(pbufchain, ngtcp2_max(1024, datalen), conn->mem); + if (rv != 0) { + return rv; + } + } + + *pdata = (*pbufchain)->buf.last; + (*pbufchain)->buf.last = ngtcp2_cpymem((*pbufchain)->buf.last, data, datalen); + + return 0; +} + +int ngtcp2_conn_submit_crypto_data(ngtcp2_conn *conn, + ngtcp2_crypto_level crypto_level, + const uint8_t *data, const size_t datalen) { + ngtcp2_pktns *pktns; + ngtcp2_frame_chain *frc; + ngtcp2_crypto *fr; + int rv; + + if (datalen == 0) { + return 0; + } + + switch (crypto_level) { + case NGTCP2_CRYPTO_LEVEL_INITIAL: + assert(conn->in_pktns); + pktns = conn->in_pktns; + break; + case NGTCP2_CRYPTO_LEVEL_HANDSHAKE: + assert(conn->hs_pktns); + pktns = conn->hs_pktns; + break; + case NGTCP2_CRYPTO_LEVEL_APPLICATION: + pktns = &conn->pktns; + break; + default: + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + rv = conn_buffer_crypto_data(conn, &data, pktns, data, datalen); + if (rv != 0) { + return rv; + } + + rv = ngtcp2_frame_chain_objalloc_new(&frc, &conn->frc_objalloc); + if (rv != 0) { + return rv; + } + + fr = &frc->fr.crypto; + + fr->type = NGTCP2_FRAME_CRYPTO; + fr->offset = pktns->crypto.tx.offset; + fr->datacnt = 1; + fr->data[0].len = datalen; + fr->data[0].base = (uint8_t *)data; + + rv = ngtcp2_ksl_insert(&pktns->crypto.tx.frq, NULL, &fr->offset, frc); + if (rv != 0) { + ngtcp2_frame_chain_objalloc_del(frc, &conn->frc_objalloc, conn->mem); + return rv; + } + + pktns->crypto.strm.tx.offset += datalen; + pktns->crypto.tx.offset += datalen; + + return 0; +} + +int ngtcp2_conn_submit_new_token(ngtcp2_conn *conn, const uint8_t *token, + size_t tokenlen) { + int rv; + ngtcp2_frame_chain *nfrc; + + assert(conn->server); + assert(token); + assert(tokenlen); + + rv = ngtcp2_frame_chain_new_token_objalloc_new( + &nfrc, token, tokenlen, &conn->frc_objalloc, conn->mem); + if (rv != 0) { + return rv; + } + + nfrc->next = conn->pktns.tx.frq; + conn->pktns.tx.frq = nfrc; + + return 0; +} + +ngtcp2_strm *ngtcp2_conn_tx_strmq_top(ngtcp2_conn *conn) { + assert(!ngtcp2_pq_empty(&conn->tx.strmq)); + return ngtcp2_struct_of(ngtcp2_pq_top(&conn->tx.strmq), ngtcp2_strm, pe); +} + +void ngtcp2_conn_tx_strmq_pop(ngtcp2_conn *conn) { + ngtcp2_strm *strm = ngtcp2_conn_tx_strmq_top(conn); + assert(strm); + ngtcp2_pq_pop(&conn->tx.strmq); + strm->pe.index = NGTCP2_PQ_BAD_INDEX; +} + +int ngtcp2_conn_tx_strmq_push(ngtcp2_conn *conn, ngtcp2_strm *strm) { + return ngtcp2_pq_push(&conn->tx.strmq, &strm->pe); +} + +static int conn_has_uncommited_preferred_address_cid(ngtcp2_conn *conn) { + return conn->server && + !(conn->flags & NGTCP2_CONN_FLAG_LOCAL_TRANSPORT_PARAMS_COMMITTED) && + conn->oscid.datalen && + conn->local.transport_params.preferred_address_present; +} + +size_t ngtcp2_conn_get_num_scid(ngtcp2_conn *conn) { + return ngtcp2_ksl_len(&conn->scid.set) + + (size_t)conn_has_uncommited_preferred_address_cid(conn); +} + +size_t ngtcp2_conn_get_scid(ngtcp2_conn *conn, ngtcp2_cid *dest) { + ngtcp2_cid *origdest = dest; + ngtcp2_ksl_it it; + ngtcp2_scid *scid; + + for (it = ngtcp2_ksl_begin(&conn->scid.set); !ngtcp2_ksl_it_end(&it); + ngtcp2_ksl_it_next(&it)) { + scid = ngtcp2_ksl_it_get(&it); + *dest++ = scid->cid; + } + + if (conn_has_uncommited_preferred_address_cid(conn)) { + *dest++ = conn->local.transport_params.preferred_address.cid; + } + + return (size_t)(dest - origdest); +} + +size_t ngtcp2_conn_get_num_active_dcid(ngtcp2_conn *conn) { + size_t n = 1; /* for conn->dcid.current */ + ngtcp2_pv *pv = conn->pv; + + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED_HANDLED)) { + return 0; + } + + if (pv) { + if (pv->dcid.seq != conn->dcid.current.seq) { + ++n; + } + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + pv->fallback_dcid.seq != conn->dcid.current.seq && + pv->fallback_dcid.seq != pv->dcid.seq) { + ++n; + } + } + + n += ngtcp2_ringbuf_len(&conn->dcid.retired.rb); + + return n; +} + +static void copy_dcid_to_cid_token(ngtcp2_cid_token *dest, + const ngtcp2_dcid *src) { + dest->seq = src->seq; + dest->cid = src->cid; + ngtcp2_path_storage_init2(&dest->ps, &src->ps.path); + if ((dest->token_present = + (src->flags & NGTCP2_DCID_FLAG_TOKEN_PRESENT) != 0)) { + memcpy(dest->token, src->token, NGTCP2_STATELESS_RESET_TOKENLEN); + } +} + +size_t ngtcp2_conn_get_active_dcid(ngtcp2_conn *conn, ngtcp2_cid_token *dest) { + ngtcp2_pv *pv = conn->pv; + ngtcp2_cid_token *orig = dest; + ngtcp2_dcid *dcid; + size_t len, i; + + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_COMPLETED_HANDLED)) { + return 0; + } + + copy_dcid_to_cid_token(dest, &conn->dcid.current); + ++dest; + + if (pv) { + if (pv->dcid.seq != conn->dcid.current.seq) { + copy_dcid_to_cid_token(dest, &pv->dcid); + ++dest; + } + if ((pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE) && + pv->fallback_dcid.seq != conn->dcid.current.seq && + pv->fallback_dcid.seq != pv->dcid.seq) { + copy_dcid_to_cid_token(dest, &pv->fallback_dcid); + ++dest; + } + } + + len = ngtcp2_ringbuf_len(&conn->dcid.retired.rb); + for (i = 0; i < len; ++i) { + dcid = ngtcp2_ringbuf_get(&conn->dcid.retired.rb, i); + copy_dcid_to_cid_token(dest, dcid); + ++dest; + } + + return (size_t)(dest - orig); +} + +void ngtcp2_conn_set_local_addr(ngtcp2_conn *conn, const ngtcp2_addr *addr) { + ngtcp2_addr *dest = &conn->dcid.current.ps.path.local; + + assert(addr->addrlen <= + (ngtcp2_socklen)sizeof(conn->dcid.current.ps.local_addrbuf)); + ngtcp2_addr_copy(dest, addr); +} + +void ngtcp2_conn_set_path_user_data(ngtcp2_conn *conn, void *path_user_data) { + conn->dcid.current.ps.path.user_data = path_user_data; +} + +const ngtcp2_path *ngtcp2_conn_get_path(ngtcp2_conn *conn) { + return &conn->dcid.current.ps.path; +} + +size_t ngtcp2_conn_get_max_tx_udp_payload_size(ngtcp2_conn *conn) { + return conn->local.settings.max_tx_udp_payload_size; +} + +size_t ngtcp2_conn_get_path_max_tx_udp_payload_size(ngtcp2_conn *conn) { + if (conn->local.settings.no_tx_udp_payload_size_shaping) { + return ngtcp2_conn_get_max_tx_udp_payload_size(conn); + } + + return conn->dcid.current.max_udp_payload_size; +} + +static int conn_initiate_migration_precheck(ngtcp2_conn *conn, + const ngtcp2_addr *local_addr) { + if (!(conn->flags & NGTCP2_CONN_FLAG_HANDSHAKE_CONFIRMED) || + conn->remote.transport_params->disable_active_migration || + conn->dcid.current.cid.datalen == 0 || + (conn->pv && (conn->pv->flags & NGTCP2_PV_FLAG_PREFERRED_ADDR))) { + return NGTCP2_ERR_INVALID_STATE; + } + + if (ngtcp2_ringbuf_len(&conn->dcid.unused.rb) == 0) { + return NGTCP2_ERR_CONN_ID_BLOCKED; + } + + if (ngtcp2_addr_eq(&conn->dcid.current.ps.path.local, local_addr)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + return 0; +} + +int ngtcp2_conn_initiate_immediate_migration(ngtcp2_conn *conn, + const ngtcp2_path *path, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_dcid *dcid; + ngtcp2_duration pto, initial_pto, timeout; + ngtcp2_pv *pv; + + assert(!conn->server); + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + rv = conn_initiate_migration_precheck(conn, &path->local); + if (rv != 0) { + return rv; + } + + ngtcp2_conn_stop_pmtud(conn); + + if (conn->pv) { + rv = conn_abort_pv(conn, ts); + if (rv != 0) { + return rv; + } + } + + rv = conn_retire_dcid(conn, &conn->dcid.current, ts); + if (rv != 0) { + return rv; + } + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + ngtcp2_dcid_set_path(dcid, path); + + ngtcp2_dcid_copy(&conn->dcid.current, dcid); + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + + conn_reset_congestion_state(conn, ts); + conn_reset_ecn_validation_state(conn); + + pto = conn_compute_pto(conn, &conn->pktns); + initial_pto = conn_compute_initial_pto(conn, &conn->pktns); + timeout = 3 * ngtcp2_max(pto, initial_pto); + + /* TODO It might be better to add a new flag which indicates that a + connection should be closed if this path validation failed. The + current design allows an application to continue, by migrating + into yet another path. */ + rv = ngtcp2_pv_new(&pv, dcid, timeout, NGTCP2_PV_FLAG_NONE, &conn->log, + conn->mem); + if (rv != 0) { + return rv; + } + + conn->pv = pv; + + return conn_call_activate_dcid(conn, &conn->dcid.current); +} + +int ngtcp2_conn_initiate_migration(ngtcp2_conn *conn, const ngtcp2_path *path, + ngtcp2_tstamp ts) { + int rv; + ngtcp2_dcid *dcid; + ngtcp2_duration pto, initial_pto, timeout; + ngtcp2_pv *pv; + + assert(!conn->server); + + conn->log.last_ts = ts; + conn->qlog.last_ts = ts; + + rv = conn_initiate_migration_precheck(conn, &path->local); + if (rv != 0) { + return rv; + } + + if (conn->pv) { + rv = conn_abort_pv(conn, ts); + if (rv != 0) { + return rv; + } + } + + dcid = ngtcp2_ringbuf_get(&conn->dcid.unused.rb, 0); + ngtcp2_dcid_set_path(dcid, path); + + pto = conn_compute_pto(conn, &conn->pktns); + initial_pto = conn_compute_initial_pto(conn, &conn->pktns); + timeout = 3 * ngtcp2_max(pto, initial_pto); + + rv = ngtcp2_pv_new(&pv, dcid, timeout, NGTCP2_PV_FLAG_NONE, &conn->log, + conn->mem); + if (rv != 0) { + return rv; + } + + ngtcp2_ringbuf_pop_front(&conn->dcid.unused.rb); + conn->pv = pv; + + return conn_call_activate_dcid(conn, &pv->dcid); +} + +uint64_t ngtcp2_conn_get_max_local_streams_uni(ngtcp2_conn *conn) { + return conn->local.uni.max_streams; +} + +uint64_t ngtcp2_conn_get_max_data_left(ngtcp2_conn *conn) { + return conn->tx.max_offset - conn->tx.offset; +} + +uint64_t ngtcp2_conn_get_max_stream_data_left(ngtcp2_conn *conn, + int64_t stream_id) { + ngtcp2_strm *strm = ngtcp2_conn_find_stream(conn, stream_id); + + if (strm == NULL) { + return 0; + } + + return strm->tx.max_offset - strm->tx.offset; +} + +uint64_t ngtcp2_conn_get_streams_bidi_left(ngtcp2_conn *conn) { + uint64_t n = ngtcp2_ord_stream_id(conn->local.bidi.next_stream_id); + + return n > conn->local.bidi.max_streams + ? 0 + : conn->local.bidi.max_streams - n + 1; +} + +uint64_t ngtcp2_conn_get_streams_uni_left(ngtcp2_conn *conn) { + uint64_t n = ngtcp2_ord_stream_id(conn->local.uni.next_stream_id); + + return n > conn->local.uni.max_streams ? 0 + : conn->local.uni.max_streams - n + 1; +} + +uint64_t ngtcp2_conn_get_cwnd_left(ngtcp2_conn *conn) { + uint64_t bytes_in_flight = conn->cstat.bytes_in_flight; + uint64_t cwnd = conn_get_cwnd(conn); + + if (cwnd > bytes_in_flight) { + return cwnd - bytes_in_flight; + } + + return 0; +} + +ngtcp2_tstamp ngtcp2_conn_get_idle_expiry(ngtcp2_conn *conn) { + ngtcp2_duration trpto; + ngtcp2_duration idle_timeout; + + /* TODO Remote max_idle_timeout becomes effective after handshake + completion. */ + + if (!conn_is_handshake_completed(conn) || + conn->remote.transport_params->max_idle_timeout == 0 || + (conn->local.transport_params.max_idle_timeout && + conn->local.transport_params.max_idle_timeout < + conn->remote.transport_params->max_idle_timeout)) { + idle_timeout = conn->local.transport_params.max_idle_timeout; + } else { + idle_timeout = conn->remote.transport_params->max_idle_timeout; + } + + if (idle_timeout == 0) { + return UINT64_MAX; + } + + trpto = 3 * conn_compute_pto(conn, conn_is_handshake_completed(conn) + ? &conn->pktns + : conn->hs_pktns); + + return conn->idle_ts + ngtcp2_max(idle_timeout, trpto); +} + +ngtcp2_duration ngtcp2_conn_get_pto(ngtcp2_conn *conn) { + return conn_compute_pto( + conn, conn_is_handshake_completed(conn) ? &conn->pktns : conn->hs_pktns); +} + +void ngtcp2_conn_set_initial_crypto_ctx(ngtcp2_conn *conn, + const ngtcp2_crypto_ctx *ctx) { + assert(conn->in_pktns); + conn->in_pktns->crypto.ctx = *ctx; +} + +const ngtcp2_crypto_ctx *ngtcp2_conn_get_initial_crypto_ctx(ngtcp2_conn *conn) { + assert(conn->in_pktns); + return &conn->in_pktns->crypto.ctx; +} + +void ngtcp2_conn_set_retry_aead(ngtcp2_conn *conn, + const ngtcp2_crypto_aead *aead, + const ngtcp2_crypto_aead_ctx *aead_ctx) { + assert(!conn->crypto.retry_aead_ctx.native_handle); + + conn->crypto.retry_aead = *aead; + conn->crypto.retry_aead_ctx = *aead_ctx; +} + +void ngtcp2_conn_set_crypto_ctx(ngtcp2_conn *conn, + const ngtcp2_crypto_ctx *ctx) { + assert(conn->hs_pktns); + conn->hs_pktns->crypto.ctx = *ctx; + conn->pktns.crypto.ctx = *ctx; +} + +const ngtcp2_crypto_ctx *ngtcp2_conn_get_crypto_ctx(ngtcp2_conn *conn) { + return &conn->pktns.crypto.ctx; +} + +void ngtcp2_conn_set_early_crypto_ctx(ngtcp2_conn *conn, + const ngtcp2_crypto_ctx *ctx) { + conn->early.ctx = *ctx; +} + +const ngtcp2_crypto_ctx *ngtcp2_conn_get_early_crypto_ctx(ngtcp2_conn *conn) { + return &conn->early.ctx; +} + +void *ngtcp2_conn_get_tls_native_handle(ngtcp2_conn *conn) { + return conn->crypto.tls_native_handle; +} + +void ngtcp2_conn_set_tls_native_handle(ngtcp2_conn *conn, + void *tls_native_handle) { + conn->crypto.tls_native_handle = tls_native_handle; +} + +void ngtcp2_conn_get_connection_close_error( + ngtcp2_conn *conn, ngtcp2_connection_close_error *ccerr) { + *ccerr = conn->rx.ccerr; +} + +void ngtcp2_conn_set_tls_error(ngtcp2_conn *conn, int liberr) { + conn->crypto.tls_error = liberr; +} + +int ngtcp2_conn_get_tls_error(ngtcp2_conn *conn) { + return conn->crypto.tls_error; +} + +void ngtcp2_conn_set_tls_alert(ngtcp2_conn *conn, uint8_t alert) { + conn->crypto.tls_alert = alert; +} + +uint8_t ngtcp2_conn_get_tls_alert(ngtcp2_conn *conn) { + return conn->crypto.tls_alert; +} + +int ngtcp2_conn_is_local_stream(ngtcp2_conn *conn, int64_t stream_id) { + return conn_local_stream(conn, stream_id); +} + +int ngtcp2_conn_is_server(ngtcp2_conn *conn) { return conn->server; } + +int ngtcp2_conn_after_retry(ngtcp2_conn *conn) { + return (conn->flags & NGTCP2_CONN_FLAG_RECV_RETRY) != 0; +} + +int ngtcp2_conn_set_stream_user_data(ngtcp2_conn *conn, int64_t stream_id, + void *stream_user_data) { + ngtcp2_strm *strm = ngtcp2_conn_find_stream(conn, stream_id); + + if (strm == NULL) { + return NGTCP2_ERR_STREAM_NOT_FOUND; + } + + strm->stream_user_data = stream_user_data; + + return 0; +} + +void ngtcp2_conn_update_pkt_tx_time(ngtcp2_conn *conn, ngtcp2_tstamp ts) { + double pacing_rate; + ngtcp2_duration interval; + + if (conn->tx.pacing.pktlen == 0) { + return; + } + + if (conn->cstat.pacing_rate > 0) { + pacing_rate = conn->cstat.pacing_rate; + } else { + /* 1.25 is the under-utilization avoidance factor described in + https://datatracker.ietf.org/doc/html/rfc9002#section-7.7 */ + pacing_rate = + (double)conn->cstat.cwnd / (double)conn->cstat.smoothed_rtt * 1.25; + } + + interval = (ngtcp2_duration)((double)conn->tx.pacing.pktlen / pacing_rate); + + conn->tx.pacing.next_ts = ts + interval; + conn->tx.pacing.pktlen = 0; +} + +size_t ngtcp2_conn_get_send_quantum(ngtcp2_conn *conn) { + return conn->cstat.send_quantum; +} + +int ngtcp2_conn_track_retired_dcid_seq(ngtcp2_conn *conn, uint64_t seq) { + size_t i; + + if (conn->dcid.retire_unacked.len >= + ngtcp2_arraylen(conn->dcid.retire_unacked.seqs)) { + return NGTCP2_ERR_CONNECTION_ID_LIMIT; + } + + /* Make sure that we do not have a duplicate */ + for (i = 0; i < conn->dcid.retire_unacked.len; ++i) { + if (conn->dcid.retire_unacked.seqs[i] == seq) { + ngtcp2_unreachable(); + } + } + + conn->dcid.retire_unacked.seqs[conn->dcid.retire_unacked.len++] = seq; + + return 0; +} + +void ngtcp2_conn_untrack_retired_dcid_seq(ngtcp2_conn *conn, uint64_t seq) { + size_t i; + + for (i = 0; i < conn->dcid.retire_unacked.len; ++i) { + if (conn->dcid.retire_unacked.seqs[i] != seq) { + continue; + } + + if (i != conn->dcid.retire_unacked.len - 1) { + conn->dcid.retire_unacked.seqs[i] = + conn->dcid.retire_unacked.seqs[conn->dcid.retire_unacked.len - 1]; + } + + --conn->dcid.retire_unacked.len; + + return; + } +} + +size_t ngtcp2_conn_get_stream_loss_count(ngtcp2_conn *conn, int64_t stream_id) { + ngtcp2_strm *strm = ngtcp2_conn_find_stream(conn, stream_id); + + if (strm == NULL) { + return 0; + } + + return strm->tx.loss_count; +} + +void ngtcp2_path_challenge_entry_init(ngtcp2_path_challenge_entry *pcent, + const ngtcp2_path *path, + const uint8_t *data) { + ngtcp2_path_storage_init2(&pcent->ps, path); + memcpy(pcent->data, data, sizeof(pcent->data)); +} + +void ngtcp2_settings_default_versioned(int settings_version, + ngtcp2_settings *settings) { + (void)settings_version; + + memset(settings, 0, sizeof(*settings)); + settings->cc_algo = NGTCP2_CC_ALGO_CUBIC; + settings->initial_rtt = NGTCP2_DEFAULT_INITIAL_RTT; + settings->ack_thresh = 2; + settings->max_tx_udp_payload_size = 1500 - 48; + settings->handshake_timeout = NGTCP2_DEFAULT_HANDSHAKE_TIMEOUT; +} + +void ngtcp2_transport_params_default_versioned( + int transport_params_version, ngtcp2_transport_params *params) { + (void)transport_params_version; + + memset(params, 0, sizeof(*params)); + params->max_udp_payload_size = NGTCP2_DEFAULT_MAX_RECV_UDP_PAYLOAD_SIZE; + params->ack_delay_exponent = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT; + params->max_ack_delay = NGTCP2_DEFAULT_MAX_ACK_DELAY; + params->active_connection_id_limit = + NGTCP2_DEFAULT_ACTIVE_CONNECTION_ID_LIMIT; +} + +/* The functions prefixed with ngtcp2_pkt_ are usually put inside + ngtcp2_pkt.c. This function uses encryption construct and uses + test data defined only in ngtcp2_conn_test.c, so it is written + here. */ +ngtcp2_ssize ngtcp2_pkt_write_connection_close( + uint8_t *dest, size_t destlen, uint32_t version, const ngtcp2_cid *dcid, + const ngtcp2_cid *scid, uint64_t error_code, const uint8_t *reason, + size_t reasonlen, ngtcp2_encrypt encrypt, const ngtcp2_crypto_aead *aead, + const ngtcp2_crypto_aead_ctx *aead_ctx, const uint8_t *iv, + ngtcp2_hp_mask hp_mask, const ngtcp2_crypto_cipher *hp, + const ngtcp2_crypto_cipher_ctx *hp_ctx) { + ngtcp2_pkt_hd hd; + ngtcp2_crypto_km ckm; + ngtcp2_crypto_cc cc; + ngtcp2_ppe ppe; + ngtcp2_frame fr = {0}; + int rv; + + ngtcp2_pkt_hd_init(&hd, NGTCP2_PKT_FLAG_LONG_FORM, NGTCP2_PKT_INITIAL, dcid, + scid, /* pkt_num = */ 0, /* pkt_numlen = */ 1, version, + /* len = */ 0); + + ngtcp2_vec_init(&ckm.secret, NULL, 0); + ngtcp2_vec_init(&ckm.iv, iv, 12); + ckm.aead_ctx = *aead_ctx; + ckm.pkt_num = 0; + ckm.flags = NGTCP2_CRYPTO_KM_FLAG_NONE; + + cc.aead = *aead; + cc.hp = *hp; + cc.ckm = &ckm; + cc.hp_ctx = *hp_ctx; + cc.encrypt = encrypt; + cc.hp_mask = hp_mask; + + ngtcp2_ppe_init(&ppe, dest, destlen, &cc); + + rv = ngtcp2_ppe_encode_hd(&ppe, &hd); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return rv; + } + + if (!ngtcp2_ppe_ensure_hp_sample(&ppe)) { + return NGTCP2_ERR_NOBUF; + } + + fr.type = NGTCP2_FRAME_CONNECTION_CLOSE; + fr.connection_close.error_code = error_code; + fr.connection_close.reasonlen = reasonlen; + fr.connection_close.reason = (uint8_t *)reason; + + rv = ngtcp2_ppe_encode_frame(&ppe, &fr); + if (rv != 0) { + assert(NGTCP2_ERR_NOBUF == rv); + return rv; + } + + return ngtcp2_ppe_final(&ppe, NULL); +} + +int ngtcp2_is_bidi_stream(int64_t stream_id) { return bidi_stream(stream_id); } + +uint32_t ngtcp2_select_version(const uint32_t *preferred_versions, + size_t preferred_versionslen, + const uint32_t *offered_versions, + size_t offered_versionslen) { + size_t i, j; + + if (!preferred_versionslen || !offered_versionslen) { + return 0; + } + + for (i = 0; i < preferred_versionslen; ++i) { + assert(ngtcp2_is_supported_version(preferred_versions[i])); + + for (j = 0; j < offered_versionslen; ++j) { + if (preferred_versions[i] == offered_versions[j]) { + return preferred_versions[i]; + } + } + } + + return 0; +} |