// 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; } skb = NULL; 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); if (type != rxrpc_rtt_rx_cancel) rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial, sent_at, resp_time); else trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i, orig_serial, acked_serial, 0, 0); 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]); 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: if (acked_serial != 0) rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial, rxrpc_rtt_rx_cancel); break; } 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); } /* 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); return; } /* 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); return; } /* 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); return; } 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: return; } 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); return; } } 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); } /* * 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); }