summaryrefslogtreecommitdiffstats
path: root/lib/ngtcp2_pkt.h
diff options
context:
space:
mode:
Diffstat (limited to 'lib/ngtcp2_pkt.h')
-rw-r--r--lib/ngtcp2_pkt.h1233
1 files changed, 1233 insertions, 0 deletions
diff --git a/lib/ngtcp2_pkt.h b/lib/ngtcp2_pkt.h
new file mode 100644
index 0000000..46f51c7
--- /dev/null
+++ b/lib/ngtcp2_pkt.h
@@ -0,0 +1,1233 @@
+/*
+ * 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.
+ */
+#ifndef NGTCP2_PKT_H
+#define NGTCP2_PKT_H
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <ngtcp2/ngtcp2.h>
+
+/* QUIC header macros */
+#define NGTCP2_HEADER_FORM_BIT 0x80
+#define NGTCP2_FIXED_BIT_MASK 0x40
+#define NGTCP2_PKT_NUMLEN_MASK 0x03
+
+/* Long header specific macros */
+#define NGTCP2_LONG_TYPE_MASK 0x30
+#define NGTCP2_LONG_RESERVED_BIT_MASK 0x0c
+
+/* Short header specific macros */
+#define NGTCP2_SHORT_SPIN_BIT_MASK 0x20
+#define NGTCP2_SHORT_RESERVED_BIT_MASK 0x18
+#define NGTCP2_SHORT_KEY_PHASE_BIT 0x04
+
+/* NGTCP2_SR_TYPE is a Type field of Stateless Reset. */
+#define NGTCP2_SR_TYPE 0x1f
+
+/* NGTCP2_MIN_LONG_HEADERLEN is the minimum length of long header.
+ That is (1|1|TT|RR|PP)<1> + VERSION<4> + DCIL<1> + SCIL<1> +
+ LENGTH<1> + PKN<1> */
+#define NGTCP2_MIN_LONG_HEADERLEN (1 + 4 + 1 + 1 + 1 + 1)
+
+#define NGTCP2_STREAM_FIN_BIT 0x01
+#define NGTCP2_STREAM_LEN_BIT 0x02
+#define NGTCP2_STREAM_OFF_BIT 0x04
+
+/* NGTCP2_STREAM_OVERHEAD is the maximum number of bytes required
+ other than payload for STREAM frame. That is from type field to
+ the beginning of the payload. */
+#define NGTCP2_STREAM_OVERHEAD (1 + 8 + 8 + 8)
+
+/* NGTCP2_CRYPTO_OVERHEAD is the maximum number of bytes required
+ other than payload for CRYPTO frame. That is from type field to
+ the beginning of the payload. */
+#define NGTCP2_CRYPTO_OVERHEAD (1 + 8 + 8)
+
+/* NGTCP2_DATAGRAM_OVERHEAD is the maximum number of bytes required
+ other than payload for DATAGRAM frame. That is from type field to
+ the beginning of the payload. */
+#define NGTCP2_DATAGRAM_OVERHEAD (1 + 8)
+
+/* NGTCP2_MIN_FRAME_PAYLOADLEN is the minimum frame payload length. */
+#define NGTCP2_MIN_FRAME_PAYLOADLEN 16
+
+/* NGTCP2_MAX_SERVER_STREAM_ID_BIDI is the maximum bidirectional
+ server stream ID. */
+#define NGTCP2_MAX_SERVER_STREAM_ID_BIDI ((int64_t)0x3ffffffffffffffdll)
+/* NGTCP2_MAX_CLIENT_STREAM_ID_BIDI is the maximum bidirectional
+ client stream ID. */
+#define NGTCP2_MAX_CLIENT_STREAM_ID_BIDI ((int64_t)0x3ffffffffffffffcll)
+/* NGTCP2_MAX_SERVER_STREAM_ID_UNI is the maximum unidirectional
+ server stream ID. */
+#define NGTCP2_MAX_SERVER_STREAM_ID_UNI ((int64_t)0x3fffffffffffffffll)
+/* NGTCP2_MAX_CLIENT_STREAM_ID_UNI is the maximum unidirectional
+ client stream ID. */
+#define NGTCP2_MAX_CLIENT_STREAM_ID_UNI ((int64_t)0x3ffffffffffffffell)
+
+/* NGTCP2_MAX_NUM_ACK_RANGES is the maximum number of Additional ACK
+ ranges which this library can create, or decode. */
+#define NGTCP2_MAX_ACK_RANGES 32
+
+/* NGTCP2_MAX_PKT_NUM is the maximum packet number. */
+#define NGTCP2_MAX_PKT_NUM ((int64_t)((1ll << 62) - 1))
+
+/* NGTCP2_MIN_PKT_EXPANDLEN is the minimum packet size expansion in
+ addition to the minimum DCID length to hide/trigger Stateless
+ Reset. */
+#define NGTCP2_MIN_PKT_EXPANDLEN 22
+
+/* NGTCP2_RETRY_TAGLEN is the length of Retry packet integrity tag. */
+#define NGTCP2_RETRY_TAGLEN 16
+
+/* NGTCP2_HARD_MAX_UDP_PAYLOAD_SIZE is the maximum UDP payload size
+ that this library can write. */
+#define NGTCP2_HARD_MAX_UDP_PAYLOAD_SIZE ((1 << 24) - 1)
+
+/* NGTCP2_PKT_LENGTHLEN is the number of bytes that is occupied by
+ Length field in Long packet header. */
+#define NGTCP2_PKT_LENGTHLEN 4
+
+/* NGTCP2_PKT_TYPE_INITIAL_V1 is Initial long header packet type for
+ QUIC v1. */
+#define NGTCP2_PKT_TYPE_INITIAL_V1 0x0
+/* NGTCP2_PKT_TYPE_0RTT_V1 is 0RTT long header packet type for QUIC
+ v1. */
+#define NGTCP2_PKT_TYPE_0RTT_V1 0x1
+/* NGTCP2_PKT_TYPE_HANDSHAKE_V1 is Handshake long header packet type
+ for QUIC v1. */
+#define NGTCP2_PKT_TYPE_HANDSHAKE_V1 0x2
+/* NGTCP2_PKT_TYPE_RETRY_V1 is Retry long header packet type for QUIC
+ v1. */
+#define NGTCP2_PKT_TYPE_RETRY_V1 0x3
+
+/* NGTCP2_PKT_TYPE_INITIAL_V2_DRAFT is Initial long header packet type
+ for QUIC v2 draft. */
+#define NGTCP2_PKT_TYPE_INITIAL_V2_DRAFT 0x1
+/* NGTCP2_PKT_TYPE_0RTT_V2_DRAFT is 0RTT long header packet type for
+ QUIC v2 draft. */
+#define NGTCP2_PKT_TYPE_0RTT_V2_DRAFT 0x2
+/* NGTCP2_PKT_TYPE_HANDSHAKE_V2_DRAFT is Handshake long header packet
+ type for QUIC v2 draft. */
+#define NGTCP2_PKT_TYPE_HANDSHAKE_V2_DRAFT 0x3
+/* NGTCP2_PKT_TYPE_RETRY_V2_DRAFT is Retry long header packet type for
+ QUIC v2 draft. */
+#define NGTCP2_PKT_TYPE_RETRY_V2_DRAFT 0x0
+
+typedef struct ngtcp2_pkt_retry {
+ ngtcp2_cid odcid;
+ ngtcp2_vec token;
+ uint8_t tag[NGTCP2_RETRY_TAGLEN];
+} ngtcp2_pkt_retry;
+
+typedef enum {
+ NGTCP2_FRAME_PADDING = 0x00,
+ NGTCP2_FRAME_PING = 0x01,
+ NGTCP2_FRAME_ACK = 0x02,
+ NGTCP2_FRAME_ACK_ECN = 0x03,
+ NGTCP2_FRAME_RESET_STREAM = 0x04,
+ NGTCP2_FRAME_STOP_SENDING = 0x05,
+ NGTCP2_FRAME_CRYPTO = 0x06,
+ NGTCP2_FRAME_NEW_TOKEN = 0x07,
+ NGTCP2_FRAME_STREAM = 0x08,
+ NGTCP2_FRAME_MAX_DATA = 0x10,
+ NGTCP2_FRAME_MAX_STREAM_DATA = 0x11,
+ NGTCP2_FRAME_MAX_STREAMS_BIDI = 0x12,
+ NGTCP2_FRAME_MAX_STREAMS_UNI = 0x13,
+ NGTCP2_FRAME_DATA_BLOCKED = 0x14,
+ NGTCP2_FRAME_STREAM_DATA_BLOCKED = 0x15,
+ NGTCP2_FRAME_STREAMS_BLOCKED_BIDI = 0x16,
+ NGTCP2_FRAME_STREAMS_BLOCKED_UNI = 0x17,
+ NGTCP2_FRAME_NEW_CONNECTION_ID = 0x18,
+ NGTCP2_FRAME_RETIRE_CONNECTION_ID = 0x19,
+ NGTCP2_FRAME_PATH_CHALLENGE = 0x1a,
+ NGTCP2_FRAME_PATH_RESPONSE = 0x1b,
+ NGTCP2_FRAME_CONNECTION_CLOSE = 0x1c,
+ NGTCP2_FRAME_CONNECTION_CLOSE_APP = 0x1d,
+ NGTCP2_FRAME_HANDSHAKE_DONE = 0x1e,
+ NGTCP2_FRAME_DATAGRAM = 0x30,
+ NGTCP2_FRAME_DATAGRAM_LEN = 0x31,
+} ngtcp2_frame_type;
+
+typedef struct ngtcp2_stream {
+ uint8_t type;
+ /**
+ * flags of decoded STREAM frame. This gets ignored when encoding
+ * STREAM frame.
+ */
+ uint8_t flags;
+ uint8_t fin;
+ int64_t stream_id;
+ uint64_t offset;
+ /* datacnt is the number of elements that data contains. Although
+ the length of data is 1 in this definition, the library may
+ allocate extra bytes to hold more elements. */
+ size_t datacnt;
+ /* data is the array of ngtcp2_vec which references data. */
+ ngtcp2_vec data[1];
+} ngtcp2_stream;
+
+typedef struct ngtcp2_ack_range {
+ uint64_t gap;
+ uint64_t len;
+} ngtcp2_ack_range;
+
+typedef struct ngtcp2_ack {
+ uint8_t type;
+ int64_t largest_ack;
+ uint64_t ack_delay;
+ /**
+ * ack_delay_unscaled is an ack_delay multiplied by
+ * 2**ack_delay_component * NGTCP2_MICROSECONDS.
+ */
+ ngtcp2_duration ack_delay_unscaled;
+ struct {
+ uint64_t ect0;
+ uint64_t ect1;
+ uint64_t ce;
+ } ecn;
+ uint64_t first_ack_range;
+ size_t rangecnt;
+ ngtcp2_ack_range ranges[1];
+} ngtcp2_ack;
+
+typedef struct ngtcp2_padding {
+ uint8_t type;
+ /**
+ * The length of contiguous PADDING frames.
+ */
+ size_t len;
+} ngtcp2_padding;
+
+typedef struct ngtcp2_reset_stream {
+ uint8_t type;
+ int64_t stream_id;
+ uint64_t app_error_code;
+ uint64_t final_size;
+} ngtcp2_reset_stream;
+
+typedef struct ngtcp2_connection_close {
+ uint8_t type;
+ uint64_t error_code;
+ uint64_t frame_type;
+ size_t reasonlen;
+ uint8_t *reason;
+} ngtcp2_connection_close;
+
+typedef struct ngtcp2_max_data {
+ uint8_t type;
+ /**
+ * max_data is Maximum Data.
+ */
+ uint64_t max_data;
+} ngtcp2_max_data;
+
+typedef struct ngtcp2_max_stream_data {
+ uint8_t type;
+ int64_t stream_id;
+ uint64_t max_stream_data;
+} ngtcp2_max_stream_data;
+
+typedef struct ngtcp2_max_streams {
+ uint8_t type;
+ uint64_t max_streams;
+} ngtcp2_max_streams;
+
+typedef struct ngtcp2_ping {
+ uint8_t type;
+} ngtcp2_ping;
+
+typedef struct ngtcp2_data_blocked {
+ uint8_t type;
+ uint64_t offset;
+} ngtcp2_data_blocked;
+
+typedef struct ngtcp2_stream_data_blocked {
+ uint8_t type;
+ int64_t stream_id;
+ uint64_t offset;
+} ngtcp2_stream_data_blocked;
+
+typedef struct ngtcp2_streams_blocked {
+ uint8_t type;
+ uint64_t max_streams;
+} ngtcp2_streams_blocked;
+
+typedef struct ngtcp2_new_connection_id {
+ uint8_t type;
+ uint64_t seq;
+ uint64_t retire_prior_to;
+ ngtcp2_cid cid;
+ uint8_t stateless_reset_token[NGTCP2_STATELESS_RESET_TOKENLEN];
+} ngtcp2_new_connection_id;
+
+typedef struct ngtcp2_stop_sending {
+ uint8_t type;
+ int64_t stream_id;
+ uint64_t app_error_code;
+} ngtcp2_stop_sending;
+
+typedef struct ngtcp2_path_challenge {
+ uint8_t type;
+ uint8_t data[NGTCP2_PATH_CHALLENGE_DATALEN];
+} ngtcp2_path_challenge;
+
+typedef struct ngtcp2_path_response {
+ uint8_t type;
+ uint8_t data[NGTCP2_PATH_CHALLENGE_DATALEN];
+} ngtcp2_path_response;
+
+typedef struct ngtcp2_crypto {
+ uint8_t type;
+ uint64_t offset;
+ /* datacnt is the number of elements that data contains. Although
+ the length of data is 1 in this definition, the library may
+ allocate extra bytes to hold more elements. */
+ size_t datacnt;
+ /* data is the array of ngtcp2_vec which references data. */
+ ngtcp2_vec data[1];
+} ngtcp2_crypto;
+
+typedef struct ngtcp2_new_token {
+ uint8_t type;
+ ngtcp2_vec token;
+} ngtcp2_new_token;
+
+typedef struct ngtcp2_retire_connection_id {
+ uint8_t type;
+ uint64_t seq;
+} ngtcp2_retire_connection_id;
+
+typedef struct ngtcp2_handshake_done {
+ uint8_t type;
+} ngtcp2_handshake_done;
+
+typedef struct ngtcp2_datagram {
+ uint8_t type;
+ /* dgram_id is an opaque identifier chosen by an application. */
+ uint64_t dgram_id;
+ /* datacnt is the number of elements that data contains. */
+ size_t datacnt;
+ /* data is a pointer to ngtcp2_vec array that stores data. */
+ ngtcp2_vec *data;
+ /* rdata is conveniently embedded to ngtcp2_datagram, so that data
+ field can just point to the address of this field to store a
+ single vector which is the case when DATAGRAM is received from a
+ remote endpoint. */
+ ngtcp2_vec rdata[1];
+} ngtcp2_datagram;
+
+typedef union ngtcp2_frame {
+ uint8_t type;
+ ngtcp2_stream stream;
+ ngtcp2_ack ack;
+ ngtcp2_padding padding;
+ ngtcp2_reset_stream reset_stream;
+ ngtcp2_connection_close connection_close;
+ ngtcp2_max_data max_data;
+ ngtcp2_max_stream_data max_stream_data;
+ ngtcp2_max_streams max_streams;
+ ngtcp2_ping ping;
+ ngtcp2_data_blocked data_blocked;
+ ngtcp2_stream_data_blocked stream_data_blocked;
+ ngtcp2_streams_blocked streams_blocked;
+ ngtcp2_new_connection_id new_connection_id;
+ ngtcp2_stop_sending stop_sending;
+ ngtcp2_path_challenge path_challenge;
+ ngtcp2_path_response path_response;
+ ngtcp2_crypto crypto;
+ ngtcp2_new_token new_token;
+ ngtcp2_retire_connection_id retire_connection_id;
+ ngtcp2_handshake_done handshake_done;
+ ngtcp2_datagram datagram;
+} ngtcp2_frame;
+
+typedef struct ngtcp2_pkt_chain ngtcp2_pkt_chain;
+
+/*
+ * ngtcp2_pkt_chain is the chain of incoming packets buffered.
+ */
+struct ngtcp2_pkt_chain {
+ ngtcp2_path_storage path;
+ ngtcp2_pkt_info pi;
+ ngtcp2_pkt_chain *next;
+ uint8_t *pkt;
+ /* pktlen is length of a QUIC packet. */
+ size_t pktlen;
+ /* dgramlen is length of UDP datagram that a QUIC packet is
+ included. */
+ size_t dgramlen;
+ ngtcp2_tstamp ts;
+};
+
+/*
+ * ngtcp2_pkt_chain_new allocates ngtcp2_pkt_chain objects, and
+ * assigns its pointer to |*ppc|. The content of buffer pointed by
+ * |pkt| of length |pktlen| is copied into |*ppc|. The packet is
+ * obtained via the network |path|. The values of path->local and
+ * path->remote are copied into |*ppc|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_NOMEM
+ * Out of memory.
+ */
+int ngtcp2_pkt_chain_new(ngtcp2_pkt_chain **ppc, const ngtcp2_path *path,
+ const ngtcp2_pkt_info *pi, const uint8_t *pkt,
+ size_t pktlen, size_t dgramlen, ngtcp2_tstamp ts,
+ const ngtcp2_mem *mem);
+
+/*
+ * ngtcp2_pkt_chain_del deallocates |pc|. It also frees the memory
+ * pointed by |pc|.
+ */
+void ngtcp2_pkt_chain_del(ngtcp2_pkt_chain *pc, const ngtcp2_mem *mem);
+
+/*
+ * ngtcp2_pkt_hd_init initializes |hd| with the given values. If
+ * |dcid| and/or |scid| is NULL, DCID and SCID of |hd| is empty
+ * respectively. |pkt_numlen| is the number of bytes used to encode
+ * |pkt_num| and either 1, 2, or 4. |version| is QUIC version for
+ * long header. |len| is the length field of Initial, 0RTT, and
+ * Handshake packets.
+ */
+void ngtcp2_pkt_hd_init(ngtcp2_pkt_hd *hd, uint8_t flags, uint8_t type,
+ const ngtcp2_cid *dcid, const ngtcp2_cid *scid,
+ int64_t pkt_num, size_t pkt_numlen, uint32_t version,
+ size_t len);
+
+/*
+ * ngtcp2_pkt_encode_hd_long encodes |hd| as QUIC long header into
+ * |out| which has length |outlen|. It returns the number of bytes
+ * written into |outlen| if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer is too short
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_hd_long(uint8_t *out, size_t outlen,
+ const ngtcp2_pkt_hd *hd);
+
+/*
+ * ngtcp2_pkt_encode_hd_short encodes |hd| as QUIC short header into
+ * |out| which has length |outlen|. It returns the number of bytes
+ * written into |outlen| if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer is too short
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_hd_short(uint8_t *out, size_t outlen,
+ const ngtcp2_pkt_hd *hd);
+
+/**
+ * @function
+ *
+ * `ngtcp2_pkt_decode_frame` decodes a QUIC frame from the buffer
+ * pointed by |payload| whose length is |payloadlen|.
+ *
+ * This function returns the number of bytes read to decode a single
+ * frame if it succeeds, or one of the following negative error codes:
+ *
+ * :enum:`NGTCP2_ERR_FRAME_ENCODING`
+ * Frame is badly formatted; or frame type is unknown; or
+ * |payloadlen| is 0.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_frame(ngtcp2_frame *dest, const uint8_t *payload,
+ size_t payloadlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_pkt_encode_frame` encodes a frame |fm| into the buffer
+ * pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written to the buffer, or
+ * one of the following negative error codes:
+ *
+ * :enum:`NGTCP2_ERR_NOBUF`
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_frame(uint8_t *out, size_t outlen,
+ ngtcp2_frame *fr);
+
+/*
+ * ngtcp2_pkt_decode_version_negotiation decodes Version Negotiation
+ * packet payload |payload| of length |payloadlen|, and stores the
+ * result in |dest|. |dest| must have enough capacity to store the
+ * result. |payloadlen| also must be a multiple of sizeof(uint32_t).
+ *
+ * This function returns the number of versions written in |dest|.
+ */
+size_t ngtcp2_pkt_decode_version_negotiation(uint32_t *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_stateless_reset decodes Stateless Reset payload
+ * |payload| of length |payloadlen|. The |payload| must start with
+ * Stateless Reset Token.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_INVALID_ARGUMENT
+ * Payloadlen is too short.
+ */
+int ngtcp2_pkt_decode_stateless_reset(ngtcp2_pkt_stateless_reset *sr,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_retry decodes Retry packet payload |payload| of
+ * length |payloadlen|. The |payload| must start with Retry token
+ * field.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_INVALID_ARGUMENT
+ * Payloadlen is too short.
+ */
+int ngtcp2_pkt_decode_retry(ngtcp2_pkt_retry *dest, const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_stream_frame decodes STREAM frame from |payload|
+ * of length |payloadlen|. The result is stored in the object pointed
+ * by |dest|. STREAM frame must start at payload[0]. This function
+ * finishes when it decodes one STREAM frame, and returns the exact
+ * number of bytes read to decode a frame if it succeeds, or one of
+ * the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include STREAM frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_stream_frame(ngtcp2_stream *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_ack_frame decodes ACK frame from |payload| of
+ * length |payloadlen|. The result is stored in the object pointed by
+ * |dest|. ACK frame must start at payload[0]. This function
+ * finishes when it decodes one ACK frame, and returns the exact
+ * number of bytes read to decode a frame if it succeeds, or one of
+ * the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include ACK frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_ack_frame(ngtcp2_ack *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_padding_frame decodes contiguous PADDING frames
+ * from |payload| of length |payloadlen|. It continues to parse
+ * frames as long as the frame type is PADDING. This finishes when it
+ * encounters the frame type which is not PADDING, or all input data
+ * is read. The first byte (payload[0]) must be NGTCP2_FRAME_PADDING.
+ * This function returns the exact number of bytes read to decode
+ * PADDING frames.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_padding_frame(ngtcp2_padding *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_reset_stream_frame decodes RESET_STREAM frame
+ * from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. RESET_STREAM frame must start at
+ * payload[0]. This function finishes when it decodes one
+ * RESET_STREAM frame, and returns the exact number of bytes read to
+ * decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include RESET_STREAM frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_reset_stream_frame(ngtcp2_reset_stream *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_connection_close_frame decodes CONNECTION_CLOSE
+ * frame from |payload| of length |payloadlen|. The result is stored
+ * in the object pointed by |dest|. CONNECTION_CLOSE frame must start
+ * at payload[0]. This function finishes it decodes one
+ * CONNECTION_CLOSE frame, and returns the exact number of bytes read
+ * to decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include CONNECTION_CLOSE frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_connection_close_frame(
+ ngtcp2_connection_close *dest, const uint8_t *payload, size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_max_data_frame decodes MAX_DATA frame from
+ * |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. MAX_DATA frame must start at payload[0].
+ * This function finishes when it decodes one MAX_DATA frame, and
+ * returns the exact number of bytes read to decode a frame if it
+ * succeeds, or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include MAX_DATA frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_max_data_frame(ngtcp2_max_data *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_max_stream_data_frame decodes MAX_STREAM_DATA
+ * frame from |payload| of length |payloadlen|. The result is stored
+ * in the object pointed by |dest|. MAX_STREAM_DATA frame must start
+ * at payload[0]. This function finishes when it decodes one
+ * MAX_STREAM_DATA frame, and returns the exact number of bytes read
+ * to decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include MAX_STREAM_DATA frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_max_stream_data_frame(
+ ngtcp2_max_stream_data *dest, const uint8_t *payload, size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_max_streams_frame decodes MAX_STREAMS frame from
+ * |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. MAX_STREAMS frame must start at
+ * payload[0]. This function finishes when it decodes one MAX_STREAMS
+ * frame, and returns the exact number of bytes read to decode a frame
+ * if it succeeds, or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include MAX_STREAMS frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_max_streams_frame(ngtcp2_max_streams *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_ping_frame decodes PING frame from |payload| of
+ * length |payloadlen|. The result is stored in the object pointed by
+ * |dest|. PING frame must start at payload[0]. This function
+ * finishes when it decodes one PING frame, and returns the exact
+ * number of bytes read to decode a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_ping_frame(ngtcp2_ping *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_data_blocked_frame decodes DATA_BLOCKED frame
+ * from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. DATA_BLOCKED frame must start at
+ * payload[0]. This function finishes when it decodes one
+ * DATA_BLOCKED frame, and returns the exact number of bytes read to
+ * decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include DATA_BLOCKED frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_data_blocked_frame(ngtcp2_data_blocked *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_stream_data_blocked_frame decodes
+ * STREAM_DATA_BLOCKED frame from |payload| of length |payloadlen|.
+ * The result is stored in the object pointed by |dest|.
+ * STREAM_DATA_BLOCKED frame must start at payload[0]. This function
+ * finishes when it decodes one STREAM_DATA_BLOCKED frame, and returns
+ * the exact number of bytes read to decode a frame if it succeeds, or
+ * one of the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include STREAM_DATA_BLOCKED frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_decode_stream_data_blocked_frame(ngtcp2_stream_data_blocked *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_streams_blocked_frame decodes STREAMS_BLOCKED
+ * frame from |payload| of length |payloadlen|. The result is stored
+ * in the object pointed by |dest|. STREAMS_BLOCKED frame must start
+ * at payload[0]. This function finishes when it decodes one
+ * STREAMS_BLOCKED frame, and returns the exact number of bytes read
+ * to decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include STREAMS_BLOCKED frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_streams_blocked_frame(
+ ngtcp2_streams_blocked *dest, const uint8_t *payload, size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_new_connection_id_frame decodes NEW_CONNECTION_ID
+ * frame from |payload| of length |payloadlen|. The result is stored
+ * in the object pointed by |dest|. NEW_CONNECTION_ID frame must
+ * start at payload[0]. This function finishes when it decodes one
+ * NEW_CONNECTION_ID frame, and returns the exact number of bytes read
+ * to decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include NEW_CONNECTION_ID frame; or the
+ * length of CID is strictly less than NGTCP2_MIN_CIDLEN or
+ * greater than NGTCP2_MAX_CIDLEN.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_new_connection_id_frame(
+ ngtcp2_new_connection_id *dest, const uint8_t *payload, size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_stop_sending_frame decodes STOP_SENDING frame
+ * from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. STOP_SENDING frame must start at
+ * payload[0]. This function finishes when it decodes one
+ * STOP_SENDING frame, and returns the exact number of bytes read to
+ * decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include STOP_SENDING frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_stop_sending_frame(ngtcp2_stop_sending *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_path_challenge_frame decodes PATH_CHALLENGE frame
+ * from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. PATH_CHALLENGE frame must start at
+ * payload[0]. This function finishes when it decodes one
+ * PATH_CHALLENGE frame, and returns the exact number of bytes read to
+ * decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include PATH_CHALLENGE frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_path_challenge_frame(ngtcp2_path_challenge *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_path_response_frame decodes PATH_RESPONSE frame
+ * from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. PATH_RESPONSE frame must start at
+ * payload[0]. This function finishes when it decodes one
+ * PATH_RESPONSE frame, and returns the exact number of bytes read to
+ * decode a frame if it succeeds, or one of the following negative
+ * error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include PATH_RESPONSE frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_path_response_frame(ngtcp2_path_response *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_crypto_frame decodes CRYPTO frame from |payload|
+ * of length |payloadlen|. The result is stored in the object pointed
+ * by |dest|. CRYPTO frame must start at payload[0]. This function
+ * finishes when it decodes one CRYPTO frame, and returns the exact
+ * number of bytes read to decode a frame if it succeeds, or one of
+ * the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include CRYPTO frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_crypto_frame(ngtcp2_crypto *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_new_token_frame decodes NEW_TOKEN frame from
+ * |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. NEW_TOKEN frame must start at
+ * payload[0]. This function finishes when it decodes one NEW_TOKEN
+ * frame, and returns the exact number of bytes read to decode a frame
+ * if it succeeds, or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include NEW_TOKEN frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_new_token_frame(ngtcp2_new_token *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_retire_connection_id_frame decodes RETIRE_CONNECTION_ID
+ * frame from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. RETIRE_CONNECTION_ID frame must start at
+ * payload[0]. This function finishes when it decodes one RETIRE_CONNECTION_ID
+ * frame, and returns the exact number of bytes read to decode a frame
+ * if it succeeds, or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include RETIRE_CONNECTION_ID frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_decode_retire_connection_id_frame(ngtcp2_retire_connection_id *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_handshake_done_frame decodes HANDSHAKE_DONE frame
+ * from |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. HANDSHAKE_DONE frame must start at
+ * payload[0]. This function finishes when it decodes one
+ * HANDSHAKE_DONE frame, and returns the exact number of bytes read to
+ * decode a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_handshake_done_frame(ngtcp2_handshake_done *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_decode_datagram_frame decodes DATAGRAM frame from
+ * |payload| of length |payloadlen|. The result is stored in the
+ * object pointed by |dest|. DATAGRAM frame must start at payload[0].
+ * This function finishes when it decodes one DATAGRAM frame, and
+ * returns the exact number of bytes read to decode a frame if it
+ * succeeds, or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_FRAME_ENCODING
+ * Payload is too short to include DATAGRAM frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_decode_datagram_frame(ngtcp2_datagram *dest,
+ const uint8_t *payload,
+ size_t payloadlen);
+
+/*
+ * ngtcp2_pkt_encode_stream_frame encodes STREAM frame |fr| into the
+ * buffer pointed by |out| of length |outlen|.
+ *
+ * This function assigns <the serialized frame type> &
+ * ~NGTCP2_FRAME_STREAM to fr->flags.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_stream_frame(uint8_t *out, size_t outlen,
+ ngtcp2_stream *fr);
+
+/*
+ * ngtcp2_pkt_encode_ack_frame encodes ACK frame |fr| into the buffer
+ * pointed by |out| of length |outlen|.
+ *
+ * This function assigns <the serialized frame type> &
+ * ~NGTCP2_FRAME_ACK to fr->flags.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_ack_frame(uint8_t *out, size_t outlen,
+ ngtcp2_ack *fr);
+
+/*
+ * ngtcp2_pkt_encode_padding_frame encodes PADDING frame |fr| into the
+ * buffer pointed by |out| of length |outlen|.
+ *
+ * This function encodes consecutive fr->len PADDING frames.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write frame(s).
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_padding_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_padding *fr);
+
+/*
+ * ngtcp2_pkt_encode_reset_stream_frame encodes RESET_STREAM frame
+ * |fr| into the buffer pointed by |out| of length |buflen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_reset_stream_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_reset_stream *fr);
+
+/*
+ * ngtcp2_pkt_encode_connection_close_frame encodes CONNECTION_CLOSE
+ * frame |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_connection_close_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_connection_close *fr);
+
+/*
+ * ngtcp2_pkt_encode_max_data_frame encodes MAX_DATA frame |fr| into
+ * the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_max_data_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_max_data *fr);
+
+/*
+ * ngtcp2_pkt_encode_max_stream_data_frame encodes MAX_STREAM_DATA
+ * frame |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_max_stream_data_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_max_stream_data *fr);
+
+/*
+ * ngtcp2_pkt_encode_max_streams_frame encodes MAX_STREAMS
+ * frame |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_max_streams_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_max_streams *fr);
+
+/*
+ * ngtcp2_pkt_encode_ping_frame encodes PING frame |fr| into the
+ * buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_ping_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_ping *fr);
+
+/*
+ * ngtcp2_pkt_encode_data_blocked_frame encodes DATA_BLOCKED frame
+ * |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_data_blocked_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_data_blocked *fr);
+
+/*
+ * ngtcp2_pkt_encode_stream_data_blocked_frame encodes
+ * STREAM_DATA_BLOCKED frame |fr| into the buffer pointed by |out| of
+ * length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_stream_data_blocked_frame(
+ uint8_t *out, size_t outlen, const ngtcp2_stream_data_blocked *fr);
+
+/*
+ * ngtcp2_pkt_encode_streams_blocked_frame encodes STREAMS_BLOCKED
+ * frame |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_streams_blocked_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_streams_blocked *fr);
+
+/*
+ * ngtcp2_pkt_encode_new_connection_id_frame encodes NEW_CONNECTION_ID
+ * frame |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_new_connection_id_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_new_connection_id *fr);
+
+/*
+ * ngtcp2_pkt_encode_stop_sending_frame encodes STOP_SENDING frame
+ * |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_stop_sending_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_stop_sending *fr);
+
+/*
+ * ngtcp2_pkt_encode_path_challenge_frame encodes PATH_CHALLENGE frame
+ * |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_path_challenge_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_path_challenge *fr);
+
+/*
+ * ngtcp2_pkt_encode_path_response_frame encodes PATH_RESPONSE frame
+ * |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_path_response_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_path_response *fr);
+
+/*
+ * ngtcp2_pkt_encode_crypto_frame encodes CRYPTO frame |fr| into the
+ * buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_crypto_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_crypto *fr);
+
+/*
+ * ngtcp2_pkt_encode_new_token_frame encodes NEW_TOKEN frame |fr| into
+ * the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_new_token_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_new_token *fr);
+
+/*
+ * ngtcp2_pkt_encode_retire_connection_id_frame encodes RETIRE_CONNECTION_ID
+ * frame |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_retire_connection_id_frame(
+ uint8_t *out, size_t outlen, const ngtcp2_retire_connection_id *fr);
+
+/*
+ * ngtcp2_pkt_encode_handshake_done_frame encodes HANDSHAKE_DONE frame
+ * |fr| into the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize
+ngtcp2_pkt_encode_handshake_done_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_handshake_done *fr);
+
+/*
+ * ngtcp2_pkt_encode_datagram_frame encodes DATAGRAM frame |fr| into
+ * the buffer pointed by |out| of length |outlen|.
+ *
+ * This function returns the number of bytes written if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * NGTCP2_ERR_NOBUF
+ * Buffer does not have enough capacity to write a frame.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_datagram_frame(uint8_t *out, size_t outlen,
+ const ngtcp2_datagram *fr);
+
+/*
+ * ngtcp2_pkt_adjust_pkt_num find the full 64 bits packet number for
+ * |pkt_num|, which is expected to be least significant |n| bits. The
+ * |max_pkt_num| is the highest successfully authenticated packet
+ * number.
+ */
+int64_t ngtcp2_pkt_adjust_pkt_num(int64_t max_pkt_num, int64_t pkt_num,
+ size_t n);
+
+/*
+ * ngtcp2_pkt_validate_ack checks that ack is malformed or not.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_ACK_FRAME
+ * ACK frame is malformed
+ */
+int ngtcp2_pkt_validate_ack(ngtcp2_ack *fr);
+
+/*
+ * ngtcp2_pkt_stream_max_datalen returns the maximum number of bytes
+ * which can be sent for stream denoted by |stream_id|. |offset| is
+ * an offset of within the stream. |len| is the estimated number of
+ * bytes to be sent. |left| is the size of buffer. If |left| is too
+ * small to write STREAM frame, this function returns (size_t)-1.
+ */
+size_t ngtcp2_pkt_stream_max_datalen(int64_t stream_id, uint64_t offset,
+ uint64_t len, size_t left);
+
+/*
+ * ngtcp2_pkt_crypto_max_datalen returns the maximum number of bytes
+ * which can be sent for crypto stream. |offset| is an offset of
+ * within the crypto stream. |len| is the estimated number of bytes
+ * to be sent. |left| is the size of buffer. If |left| is too small
+ * to write CRYPTO frame, this function returns (size_t)-1.
+ */
+size_t ngtcp2_pkt_crypto_max_datalen(uint64_t offset, size_t len, size_t left);
+
+/*
+ * ngtcp2_pkt_datagram_framelen returns the length of DATAGRAM frame
+ * to encode |len| bytes of data.
+ */
+size_t ngtcp2_pkt_datagram_framelen(size_t len);
+
+/*
+ * ngtcp2_pkt_verify_reserved_bits verifies that the first byte |c| of
+ * the packet header has the correct reserved bits.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_PROTO
+ * Reserved bits has wrong value.
+ */
+int ngtcp2_pkt_verify_reserved_bits(uint8_t c);
+
+/*
+ * ngtcp2_pkt_encode_pseudo_retry encodes Retry pseudo-packet in the
+ * buffer pointed by |dest| of length |destlen|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_BUF
+ * Buffer is too short.
+ */
+ngtcp2_ssize ngtcp2_pkt_encode_pseudo_retry(
+ uint8_t *dest, size_t destlen, const ngtcp2_pkt_hd *hd, uint8_t unused,
+ const ngtcp2_cid *odcid, const uint8_t *token, size_t tokenlen);
+
+/*
+ * ngtcp2_pkt_verify_retry_tag verifies Retry packet. The buffer
+ * pointed by |pkt| of length |pktlen| must contain Retry packet
+ * including packet header. The odcid and tag fields of |retry| must
+ * be specified. |aead| must be AEAD_AES_128_GCM.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_PROTO
+ * Verification failed.
+ */
+int ngtcp2_pkt_verify_retry_tag(uint32_t version, const ngtcp2_pkt_retry *retry,
+ const uint8_t *pkt, size_t pktlen,
+ ngtcp2_encrypt encrypt,
+ const ngtcp2_crypto_aead *aead,
+ const ngtcp2_crypto_aead_ctx *aead_ctx);
+
+/*
+ * ngtcp2_pkt_versioned_type returns versioned packet type for a
+ * version |version| that corresponds to the version-independent
+ * |pkt_type|.
+ */
+uint8_t ngtcp2_pkt_versioned_type(uint32_t version, uint32_t pkt_type);
+
+/**
+ * @function
+ *
+ * `ngtcp2_pkt_get_type_long` returns the version-independent long
+ * packet type. |version| is the QUIC version. |c| is the first byte
+ * of Long packet header. If |version| is not supported by the
+ * library, it returns 0.
+ */
+uint8_t ngtcp2_pkt_get_type_long(uint32_t version, uint8_t c);
+
+#endif /* NGTCP2_PKT_H */