diff options
Diffstat (limited to 'net/rxrpc/input.c')
| -rw-r--r-- | net/rxrpc/input.c | 1027 |
1 files changed, 1027 insertions, 0 deletions
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c new file mode 100644 index 000000000..92495e73b --- /dev/null +++ b/net/rxrpc/input.c @@ -0,0 +1,1027 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Processing of received RxRPC packets + * + * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include "ar-internal.h" + +static void rxrpc_proto_abort(struct rxrpc_call *call, rxrpc_seq_t seq, + enum rxrpc_abort_reason why) +{ + rxrpc_abort_call(call, seq, RX_PROTOCOL_ERROR, -EBADMSG, why); +} + +/* + * Do TCP-style congestion management [RFC 5681]. + */ +static void rxrpc_congestion_management(struct rxrpc_call *call, + struct sk_buff *skb, + struct rxrpc_ack_summary *summary, + rxrpc_serial_t acked_serial) +{ + enum rxrpc_congest_change change = rxrpc_cong_no_change; + unsigned int cumulative_acks = call->cong_cumul_acks; + unsigned int cwnd = call->cong_cwnd; + bool resend = false; + + summary->flight_size = + (call->tx_top - call->acks_hard_ack) - summary->nr_acks; + + if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) { + summary->retrans_timeo = true; + call->cong_ssthresh = max_t(unsigned int, + summary->flight_size / 2, 2); + cwnd = 1; + if (cwnd >= call->cong_ssthresh && + call->cong_mode == RXRPC_CALL_SLOW_START) { + call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; + call->cong_tstamp = skb->tstamp; + cumulative_acks = 0; + } + } + + cumulative_acks += summary->nr_new_acks; + cumulative_acks += summary->nr_rot_new_acks; + if (cumulative_acks > 255) + cumulative_acks = 255; + + summary->mode = call->cong_mode; + summary->cwnd = call->cong_cwnd; + summary->ssthresh = call->cong_ssthresh; + summary->cumulative_acks = cumulative_acks; + summary->dup_acks = call->cong_dup_acks; + + switch (call->cong_mode) { + case RXRPC_CALL_SLOW_START: + if (summary->saw_nacks) + goto packet_loss_detected; + if (summary->cumulative_acks > 0) + cwnd += 1; + if (cwnd >= call->cong_ssthresh) { + call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; + call->cong_tstamp = skb->tstamp; + } + goto out; + + case RXRPC_CALL_CONGEST_AVOIDANCE: + if (summary->saw_nacks) + goto packet_loss_detected; + + /* We analyse the number of packets that get ACK'd per RTT + * period and increase the window if we managed to fill it. + */ + if (call->peer->rtt_count == 0) + goto out; + if (ktime_before(skb->tstamp, + ktime_add_us(call->cong_tstamp, + call->peer->srtt_us >> 3))) + goto out_no_clear_ca; + change = rxrpc_cong_rtt_window_end; + call->cong_tstamp = skb->tstamp; + if (cumulative_acks >= cwnd) + cwnd++; + goto out; + + case RXRPC_CALL_PACKET_LOSS: + if (!summary->saw_nacks) + goto resume_normality; + + if (summary->new_low_nack) { + change = rxrpc_cong_new_low_nack; + call->cong_dup_acks = 1; + if (call->cong_extra > 1) + call->cong_extra = 1; + goto send_extra_data; + } + + call->cong_dup_acks++; + if (call->cong_dup_acks < 3) + goto send_extra_data; + + change = rxrpc_cong_begin_retransmission; + call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT; + call->cong_ssthresh = max_t(unsigned int, + summary->flight_size / 2, 2); + cwnd = call->cong_ssthresh + 3; + call->cong_extra = 0; + call->cong_dup_acks = 0; + resend = true; + goto out; + + case RXRPC_CALL_FAST_RETRANSMIT: + if (!summary->new_low_nack) { + if (summary->nr_new_acks == 0) + cwnd += 1; + call->cong_dup_acks++; + if (call->cong_dup_acks == 2) { + change = rxrpc_cong_retransmit_again; + call->cong_dup_acks = 0; + resend = true; + } + } else { + change = rxrpc_cong_progress; + cwnd = call->cong_ssthresh; + if (!summary->saw_nacks) + goto resume_normality; + } + goto out; + + default: + BUG(); + goto out; + } + +resume_normality: + change = rxrpc_cong_cleared_nacks; + call->cong_dup_acks = 0; + call->cong_extra = 0; + call->cong_tstamp = skb->tstamp; + if (cwnd < call->cong_ssthresh) + call->cong_mode = RXRPC_CALL_SLOW_START; + else + call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; +out: + cumulative_acks = 0; +out_no_clear_ca: + if (cwnd >= RXRPC_TX_MAX_WINDOW) + cwnd = RXRPC_TX_MAX_WINDOW; + call->cong_cwnd = cwnd; + call->cong_cumul_acks = cumulative_acks; + trace_rxrpc_congest(call, summary, acked_serial, change); + if (resend) + rxrpc_resend(call, skb); + return; + +packet_loss_detected: + change = rxrpc_cong_saw_nack; + call->cong_mode = RXRPC_CALL_PACKET_LOSS; + call->cong_dup_acks = 0; + goto send_extra_data; + +send_extra_data: + /* Send some previously unsent DATA if we have some to advance the ACK + * state. + */ + if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) || + summary->nr_acks != call->tx_top - call->acks_hard_ack) { + call->cong_extra++; + wake_up(&call->waitq); + } + goto out_no_clear_ca; +} + +/* + * Degrade the congestion window if we haven't transmitted a packet for >1RTT. + */ +void rxrpc_congestion_degrade(struct rxrpc_call *call) +{ + ktime_t rtt, now; + + if (call->cong_mode != RXRPC_CALL_SLOW_START && + call->cong_mode != RXRPC_CALL_CONGEST_AVOIDANCE) + return; + if (__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_AWAIT_REPLY) + return; + + rtt = ns_to_ktime(call->peer->srtt_us * (1000 / 8)); + now = ktime_get_real(); + if (!ktime_before(ktime_add(call->tx_last_sent, rtt), now)) + return; + + trace_rxrpc_reset_cwnd(call, now); + rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset); + call->tx_last_sent = now; + call->cong_mode = RXRPC_CALL_SLOW_START; + call->cong_ssthresh = max_t(unsigned int, call->cong_ssthresh, + call->cong_cwnd * 3 / 4); + call->cong_cwnd = max_t(unsigned int, call->cong_cwnd / 2, RXRPC_MIN_CWND); +} + +/* + * Apply a hard ACK by advancing the Tx window. + */ +static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to, + struct rxrpc_ack_summary *summary) +{ + struct rxrpc_txbuf *txb; + bool rot_last = false; + + list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) { + if (before_eq(txb->seq, call->acks_hard_ack)) + continue; + summary->nr_rot_new_acks++; + if (test_bit(RXRPC_TXBUF_LAST, &txb->flags)) { + set_bit(RXRPC_CALL_TX_LAST, &call->flags); + rot_last = true; + } + if (txb->seq == to) + break; + } + + if (rot_last) + set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags); + + _enter("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last); + + if (call->acks_lowest_nak == call->acks_hard_ack) { + call->acks_lowest_nak = to; + } else if (after(to, call->acks_lowest_nak)) { + summary->new_low_nack = true; + call->acks_lowest_nak = to; + } + + smp_store_release(&call->acks_hard_ack, to); + + trace_rxrpc_txqueue(call, (rot_last ? + rxrpc_txqueue_rotate_last : + rxrpc_txqueue_rotate)); + wake_up(&call->waitq); + return rot_last; +} + +/* + * End the transmission phase of a call. + * + * This occurs when we get an ACKALL packet, the first DATA packet of a reply, + * or a final ACK packet. + */ +static void rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun, + enum rxrpc_abort_reason abort_why) +{ + ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags)); + + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_CLIENT_AWAIT_REPLY: + if (reply_begun) { + rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_RECV_REPLY); + trace_rxrpc_txqueue(call, rxrpc_txqueue_end); + break; + } + + rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY); + trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply); + break; + + case RXRPC_CALL_SERVER_AWAIT_ACK: + rxrpc_call_completed(call); + trace_rxrpc_txqueue(call, rxrpc_txqueue_end); + break; + + default: + kdebug("end_tx %s", rxrpc_call_states[__rxrpc_call_state(call)]); + rxrpc_proto_abort(call, call->tx_top, abort_why); + break; + } +} + +/* + * Begin the reply reception phase of a call. + */ +static bool rxrpc_receiving_reply(struct rxrpc_call *call) +{ + struct rxrpc_ack_summary summary = { 0 }; + unsigned long now, timo; + rxrpc_seq_t top = READ_ONCE(call->tx_top); + + if (call->ackr_reason) { + now = jiffies; + timo = now + MAX_JIFFY_OFFSET; + + WRITE_ONCE(call->delay_ack_at, timo); + trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now); + } + + if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) { + if (!rxrpc_rotate_tx_window(call, top, &summary)) { + rxrpc_proto_abort(call, top, rxrpc_eproto_early_reply); + return false; + } + } + + rxrpc_end_tx_phase(call, true, rxrpc_eproto_unexpected_reply); + return true; +} + +/* + * End the packet reception phase. + */ +static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial) +{ + rxrpc_seq_t whigh = READ_ONCE(call->rx_highest_seq); + + _enter("%d,%s", call->debug_id, rxrpc_call_states[__rxrpc_call_state(call)]); + + trace_rxrpc_receive(call, rxrpc_receive_end, 0, whigh); + + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_RECV_REPLY: + rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_terminal_ack); + rxrpc_call_completed(call); + break; + + case RXRPC_CALL_SERVER_RECV_REQUEST: + rxrpc_set_call_state(call, RXRPC_CALL_SERVER_ACK_REQUEST); + call->expect_req_by = jiffies + MAX_JIFFY_OFFSET; + rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_processing_op); + break; + + default: + break; + } +} + +static void rxrpc_input_update_ack_window(struct rxrpc_call *call, + rxrpc_seq_t window, rxrpc_seq_t wtop) +{ + call->ackr_window = window; + call->ackr_wtop = wtop; +} + +/* + * Push a DATA packet onto the Rx queue. + */ +static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb, + rxrpc_seq_t window, rxrpc_seq_t wtop, + enum rxrpc_receive_trace why) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + bool last = sp->hdr.flags & RXRPC_LAST_PACKET; + + __skb_queue_tail(&call->recvmsg_queue, skb); + rxrpc_input_update_ack_window(call, window, wtop); + trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq); + if (last) + rxrpc_end_rx_phase(call, sp->hdr.serial); +} + +/* + * Process a DATA packet. + */ +static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb, + bool *_notify) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + struct sk_buff *oos; + rxrpc_serial_t serial = sp->hdr.serial; + unsigned int sack = call->ackr_sack_base; + rxrpc_seq_t window = call->ackr_window; + rxrpc_seq_t wtop = call->ackr_wtop; + rxrpc_seq_t wlimit = window + call->rx_winsize - 1; + rxrpc_seq_t seq = sp->hdr.seq; + bool last = sp->hdr.flags & RXRPC_LAST_PACKET; + int ack_reason = -1; + + rxrpc_inc_stat(call->rxnet, stat_rx_data); + if (sp->hdr.flags & RXRPC_REQUEST_ACK) + rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack); + if (sp->hdr.flags & RXRPC_JUMBO_PACKET) + rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo); + + if (last) { + if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) && + seq + 1 != wtop) + return rxrpc_proto_abort(call, seq, rxrpc_eproto_different_last); + } else { + if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && + after_eq(seq, wtop)) { + pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n", + call->debug_id, seq, window, wtop, wlimit); + return rxrpc_proto_abort(call, seq, rxrpc_eproto_data_after_last); + } + } + + if (after(seq, call->rx_highest_seq)) + call->rx_highest_seq = seq; + + trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags); + + if (before(seq, window)) { + ack_reason = RXRPC_ACK_DUPLICATE; + goto send_ack; + } + if (after(seq, wlimit)) { + ack_reason = RXRPC_ACK_EXCEEDS_WINDOW; + goto send_ack; + } + + /* Queue the packet. */ + if (seq == window) { + if (sp->hdr.flags & RXRPC_REQUEST_ACK) + ack_reason = RXRPC_ACK_REQUESTED; + /* Send an immediate ACK if we fill in a hole */ + else if (!skb_queue_empty(&call->rx_oos_queue)) + ack_reason = RXRPC_ACK_DELAY; + else + call->ackr_nr_unacked++; + + window++; + if (after(window, wtop)) { + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_none); + wtop = window; + } else { + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_advance); + sack = (sack + 1) % RXRPC_SACK_SIZE; + } + + + rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg); + + spin_lock(&call->recvmsg_queue.lock); + rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue); + *_notify = true; + + while ((oos = skb_peek(&call->rx_oos_queue))) { + struct rxrpc_skb_priv *osp = rxrpc_skb(oos); + + if (after(osp->hdr.seq, window)) + break; + + __skb_unlink(oos, &call->rx_oos_queue); + last = osp->hdr.flags & RXRPC_LAST_PACKET; + seq = osp->hdr.seq; + call->ackr_sack_table[sack] = 0; + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_fill); + sack = (sack + 1) % RXRPC_SACK_SIZE; + + window++; + rxrpc_input_queue_data(call, oos, window, wtop, + rxrpc_receive_queue_oos); + } + + spin_unlock(&call->recvmsg_queue.lock); + + call->ackr_sack_base = sack; + } else { + unsigned int slot; + + ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE; + + slot = seq - window; + sack = (sack + slot) % RXRPC_SACK_SIZE; + + if (call->ackr_sack_table[sack % RXRPC_SACK_SIZE]) { + ack_reason = RXRPC_ACK_DUPLICATE; + goto send_ack; + } + + call->ackr_sack_table[sack % RXRPC_SACK_SIZE] |= 1; + trace_rxrpc_sack(call, seq, sack, rxrpc_sack_oos); + + if (after(seq + 1, wtop)) { + wtop = seq + 1; + rxrpc_input_update_ack_window(call, window, wtop); + } + + skb_queue_walk(&call->rx_oos_queue, oos) { + struct rxrpc_skb_priv *osp = rxrpc_skb(oos); + + if (after(osp->hdr.seq, seq)) { + rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos); + __skb_queue_before(&call->rx_oos_queue, oos, skb); + goto oos_queued; + } + } + + rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos); + __skb_queue_tail(&call->rx_oos_queue, skb); + oos_queued: + trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos, + sp->hdr.serial, sp->hdr.seq); + } + +send_ack: + if (ack_reason >= 0) + rxrpc_send_ACK(call, ack_reason, serial, + rxrpc_propose_ack_input_data); + else + rxrpc_propose_delay_ACK(call, serial, + rxrpc_propose_ack_input_data); +} + +/* + * Split a jumbo packet and file the bits separately. + */ +static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_jumbo_header jhdr; + struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp; + struct sk_buff *jskb; + unsigned int offset = sizeof(struct rxrpc_wire_header); + unsigned int len = skb->len - offset; + bool notify = false; + + while (sp->hdr.flags & RXRPC_JUMBO_PACKET) { + if (len < RXRPC_JUMBO_SUBPKTLEN) + goto protocol_error; + if (sp->hdr.flags & RXRPC_LAST_PACKET) + goto protocol_error; + if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN, + &jhdr, sizeof(jhdr)) < 0) + goto protocol_error; + + jskb = skb_clone(skb, GFP_NOFS); + if (!jskb) { + kdebug("couldn't clone"); + return false; + } + rxrpc_new_skb(jskb, rxrpc_skb_new_jumbo_subpacket); + jsp = rxrpc_skb(jskb); + jsp->offset = offset; + jsp->len = RXRPC_JUMBO_DATALEN; + rxrpc_input_data_one(call, jskb, ¬ify); + rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket); + + sp->hdr.flags = jhdr.flags; + sp->hdr._rsvd = ntohs(jhdr._rsvd); + sp->hdr.seq++; + sp->hdr.serial++; + offset += RXRPC_JUMBO_SUBPKTLEN; + len -= RXRPC_JUMBO_SUBPKTLEN; + } + + sp->offset = offset; + sp->len = len; + rxrpc_input_data_one(call, skb, ¬ify); + if (notify) { + trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial); + rxrpc_notify_socket(call); + } + return true; + +protocol_error: + return false; +} + +/* + * Process a DATA packet, adding the packet to the Rx ring. The caller's + * packet ref must be passed on or discarded. + */ +static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + rxrpc_serial_t serial = sp->hdr.serial; + rxrpc_seq_t seq0 = sp->hdr.seq; + + _enter("{%x,%x,%x},{%u,%x}", + call->ackr_window, call->ackr_wtop, call->rx_highest_seq, + skb->len, seq0); + + if (__rxrpc_call_is_complete(call)) + return; + + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_CLIENT_AWAIT_REPLY: + /* Received data implicitly ACKs all of the request + * packets we sent when we're acting as a client. + */ + if (!rxrpc_receiving_reply(call)) + goto out_notify; + break; + + case RXRPC_CALL_SERVER_RECV_REQUEST: { + unsigned long timo = READ_ONCE(call->next_req_timo); + unsigned long now, expect_req_by; + + if (timo) { + now = jiffies; + expect_req_by = now + timo; + WRITE_ONCE(call->expect_req_by, expect_req_by); + rxrpc_reduce_call_timer(call, expect_req_by, now, + rxrpc_timer_set_for_idle); + } + break; + } + + default: + break; + } + + if (!rxrpc_input_split_jumbo(call, skb)) { + rxrpc_proto_abort(call, sp->hdr.seq, rxrpc_badmsg_bad_jumbo); + goto out_notify; + } + return; + +out_notify: + trace_rxrpc_notify_socket(call->debug_id, serial); + rxrpc_notify_socket(call); + _leave(" [queued]"); +} + +/* + * See if there's a cached RTT probe to complete. + */ +static void rxrpc_complete_rtt_probe(struct rxrpc_call *call, + ktime_t resp_time, + rxrpc_serial_t acked_serial, + rxrpc_serial_t ack_serial, + enum rxrpc_rtt_rx_trace type) +{ + rxrpc_serial_t orig_serial; + unsigned long avail; + ktime_t sent_at; + bool matched = false; + int i; + + avail = READ_ONCE(call->rtt_avail); + smp_rmb(); /* Read avail bits before accessing data. */ + + for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) { + if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail)) + continue; + + sent_at = call->rtt_sent_at[i]; + orig_serial = call->rtt_serial[i]; + + if (orig_serial == acked_serial) { + clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); + smp_mb(); /* Read data before setting avail bit */ + set_bit(i, &call->rtt_avail); + rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial, + sent_at, resp_time); + matched = true; + } + + /* If a later serial is being acked, then mark this slot as + * being available. + */ + if (after(acked_serial, orig_serial)) { + trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i, + orig_serial, acked_serial, 0, 0); + clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); + smp_wmb(); + set_bit(i, &call->rtt_avail); + } + } + + if (!matched) + trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0); +} + +/* + * Process the extra information that may be appended to an ACK packet + */ +static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb, + struct rxrpc_ackinfo *ackinfo) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + struct rxrpc_peer *peer; + unsigned int mtu; + bool wake = false; + u32 rwind = ntohl(ackinfo->rwind); + + if (rwind > RXRPC_TX_MAX_WINDOW) + rwind = RXRPC_TX_MAX_WINDOW; + if (call->tx_winsize != rwind) { + if (rwind > call->tx_winsize) + wake = true; + trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake); + call->tx_winsize = rwind; + } + + if (call->cong_ssthresh > rwind) + call->cong_ssthresh = rwind; + + mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU)); + + peer = call->peer; + if (mtu < peer->maxdata) { + spin_lock(&peer->lock); + peer->maxdata = mtu; + peer->mtu = mtu + peer->hdrsize; + spin_unlock(&peer->lock); + } + + if (wake) + wake_up(&call->waitq); +} + +/* + * Process individual soft ACKs. + * + * Each ACK in the array corresponds to one packet and can be either an ACK or + * a NAK. If we get find an explicitly NAK'd packet we resend immediately; + * packets that lie beyond the end of the ACK list are scheduled for resend by + * the timer on the basis that the peer might just not have processed them at + * the time the ACK was sent. + */ +static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks, + rxrpc_seq_t seq, int nr_acks, + struct rxrpc_ack_summary *summary) +{ + unsigned int i; + + for (i = 0; i < nr_acks; i++) { + if (acks[i] == RXRPC_ACK_TYPE_ACK) { + summary->nr_acks++; + summary->nr_new_acks++; + } else { + if (!summary->saw_nacks && + call->acks_lowest_nak != seq + i) { + call->acks_lowest_nak = seq + i; + summary->new_low_nack = true; + } + summary->saw_nacks = true; + } + } +} + +/* + * Return true if the ACK is valid - ie. it doesn't appear to have regressed + * with respect to the ack state conveyed by preceding ACKs. + */ +static bool rxrpc_is_ack_valid(struct rxrpc_call *call, + rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt) +{ + rxrpc_seq_t base = READ_ONCE(call->acks_first_seq); + + if (after(first_pkt, base)) + return true; /* The window advanced */ + + if (before(first_pkt, base)) + return false; /* firstPacket regressed */ + + if (after_eq(prev_pkt, call->acks_prev_seq)) + return true; /* previousPacket hasn't regressed. */ + + /* Some rx implementations put a serial number in previousPacket. */ + if (after_eq(prev_pkt, base + call->tx_winsize)) + return false; + return true; +} + +/* + * Process an ACK packet. + * + * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet + * in the ACK array. Anything before that is hard-ACK'd and may be discarded. + * + * A hard-ACK means that a packet has been processed and may be discarded; a + * soft-ACK means that the packet may be discarded and retransmission + * requested. A phase is complete when all packets are hard-ACK'd. + */ +static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_ack_summary summary = { 0 }; + struct rxrpc_ackpacket ack; + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + struct rxrpc_ackinfo info; + rxrpc_serial_t ack_serial, acked_serial; + rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt; + int nr_acks, offset, ioffset; + + _enter(""); + + offset = sizeof(struct rxrpc_wire_header); + if (skb_copy_bits(skb, offset, &ack, sizeof(ack)) < 0) + return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack); + offset += sizeof(ack); + + ack_serial = sp->hdr.serial; + acked_serial = ntohl(ack.serial); + first_soft_ack = ntohl(ack.firstPacket); + prev_pkt = ntohl(ack.previousPacket); + hard_ack = first_soft_ack - 1; + nr_acks = ack.nAcks; + summary.ack_reason = (ack.reason < RXRPC_ACK__INVALID ? + ack.reason : RXRPC_ACK__INVALID); + + trace_rxrpc_rx_ack(call, ack_serial, acked_serial, + first_soft_ack, prev_pkt, + summary.ack_reason, nr_acks); + rxrpc_inc_stat(call->rxnet, stat_rx_acks[ack.reason]); + + if (acked_serial != 0) { + switch (ack.reason) { + case RXRPC_ACK_PING_RESPONSE: + rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial, + rxrpc_rtt_rx_ping_response); + break; + case RXRPC_ACK_REQUESTED: + rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial, + rxrpc_rtt_rx_requested_ack); + break; + default: + rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial, + rxrpc_rtt_rx_other_ack); + break; + } + } + + /* If we get an EXCEEDS_WINDOW ACK from the server, it probably + * indicates that the client address changed due to NAT. The server + * lost the call because it switched to a different peer. + */ + if (unlikely(ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) && + first_soft_ack == 1 && + prev_pkt == 0 && + rxrpc_is_client_call(call)) { + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + 0, -ENETRESET); + goto send_response; + } + + /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also + * indicate a change of address. However, we can retransmit the call + * if we still have it buffered to the beginning. + */ + if (unlikely(ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) && + first_soft_ack == 1 && + prev_pkt == 0 && + call->acks_hard_ack == 0 && + rxrpc_is_client_call(call)) { + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + 0, -ENETRESET); + goto send_response; + } + + /* Discard any out-of-order or duplicate ACKs (outside lock). */ + if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) { + trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial, + first_soft_ack, call->acks_first_seq, + prev_pkt, call->acks_prev_seq); + goto send_response; + } + + info.rxMTU = 0; + ioffset = offset + nr_acks + 3; + if (skb->len >= ioffset + sizeof(info) && + skb_copy_bits(skb, ioffset, &info, sizeof(info)) < 0) + return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_info); + + if (nr_acks > 0) + skb_condense(skb); + + call->acks_latest_ts = skb->tstamp; + call->acks_first_seq = first_soft_ack; + call->acks_prev_seq = prev_pkt; + + switch (ack.reason) { + case RXRPC_ACK_PING: + break; + default: + if (after(acked_serial, call->acks_highest_serial)) + call->acks_highest_serial = acked_serial; + break; + } + + /* Parse rwind and mtu sizes if provided. */ + if (info.rxMTU) + rxrpc_input_ackinfo(call, skb, &info); + + if (first_soft_ack == 0) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_zero); + + /* Ignore ACKs unless we are or have just been transmitting. */ + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_CLIENT_AWAIT_REPLY: + case RXRPC_CALL_SERVER_SEND_REPLY: + case RXRPC_CALL_SERVER_AWAIT_ACK: + break; + default: + goto send_response; + } + + if (before(hard_ack, call->acks_hard_ack) || + after(hard_ack, call->tx_top)) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_outside_window); + if (nr_acks > call->tx_top - hard_ack) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_sack_overflow); + + if (after(hard_ack, call->acks_hard_ack)) { + if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) { + rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack); + goto send_response; + } + } + + if (nr_acks > 0) { + if (offset > (int)skb->len - nr_acks) + return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_short_sack); + rxrpc_input_soft_acks(call, skb->data + offset, first_soft_ack, + nr_acks, &summary); + } + + if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) && + summary.nr_acks == call->tx_top - hard_ack && + rxrpc_is_client_call(call)) + rxrpc_propose_ping(call, ack_serial, + rxrpc_propose_ack_ping_for_lost_reply); + + rxrpc_congestion_management(call, skb, &summary, acked_serial); + +send_response: + if (ack.reason == RXRPC_ACK_PING) + rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial, + rxrpc_propose_ack_respond_to_ping); + else if (sp->hdr.flags & RXRPC_REQUEST_ACK) + rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial, + rxrpc_propose_ack_respond_to_ack); +} + +/* + * Process an ACKALL packet. + */ +static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_ack_summary summary = { 0 }; + + if (rxrpc_rotate_tx_window(call, call->tx_top, &summary)) + rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ackall); +} + +/* + * Process an ABORT packet directed at a call. + */ +static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + + trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority); + + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + skb->priority, -ECONNABORTED); +} + +/* + * Process an incoming call packet. + */ +void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb) +{ + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + unsigned long timo; + + _enter("%p,%p", call, skb); + + if (sp->hdr.serviceId != call->dest_srx.srx_service) + call->dest_srx.srx_service = sp->hdr.serviceId; + if ((int)sp->hdr.serial - (int)call->rx_serial > 0) + call->rx_serial = sp->hdr.serial; + if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags)) + set_bit(RXRPC_CALL_RX_HEARD, &call->flags); + + timo = READ_ONCE(call->next_rx_timo); + if (timo) { + unsigned long now = jiffies, expect_rx_by; + + expect_rx_by = now + timo; + WRITE_ONCE(call->expect_rx_by, expect_rx_by); + rxrpc_reduce_call_timer(call, expect_rx_by, now, + rxrpc_timer_set_for_normal); + } + + switch (sp->hdr.type) { + case RXRPC_PACKET_TYPE_DATA: + return rxrpc_input_data(call, skb); + + case RXRPC_PACKET_TYPE_ACK: + return rxrpc_input_ack(call, skb); + + case RXRPC_PACKET_TYPE_BUSY: + /* Just ignore BUSY packets from the server; the retry and + * lifespan timers will take care of business. BUSY packets + * from the client don't make sense. + */ + return; + + case RXRPC_PACKET_TYPE_ABORT: + return rxrpc_input_abort(call, skb); + + case RXRPC_PACKET_TYPE_ACKALL: + return rxrpc_input_ackall(call, skb); + + default: + break; + } +} + +/* + * Handle a new service call on a channel implicitly completing the preceding + * call on that channel. This does not apply to client conns. + * + * TODO: If callNumber > call_id + 1, renegotiate security. + */ +void rxrpc_implicit_end_call(struct rxrpc_call *call, struct sk_buff *skb) +{ + switch (__rxrpc_call_state(call)) { + case RXRPC_CALL_SERVER_AWAIT_ACK: + rxrpc_call_completed(call); + fallthrough; + case RXRPC_CALL_COMPLETE: + break; + default: + rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ESHUTDOWN, + rxrpc_eproto_improper_term); + trace_rxrpc_improper_term(call); + break; + } + + rxrpc_input_call_event(call, skb); +} |