// SPDX-License-Identifier: GPL-2.0-or-later /* RxRPC packet reception * * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ar-internal.h" static void rxrpc_proto_abort(const char *why, struct rxrpc_call *call, rxrpc_seq_t seq) { if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) { set_bit(RXRPC_CALL_EV_ABORT, &call->events); rxrpc_queue_call(call); } } /* * 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->tx_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->nr_nacks > 0) 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->nr_nacks > 0) 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->nr_nacks == 0) 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->nr_nacks == 0) 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_RXTX_BUFF_SIZE - 1) cwnd = RXRPC_RXTX_BUFF_SIZE - 1; call->cong_cwnd = cwnd; call->cong_cumul_acks = cumulative_acks; trace_rxrpc_congest(call, summary, acked_serial, change); if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events)) rxrpc_queue_call(call); 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 (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] & RXRPC_TX_ANNO_LAST || summary->nr_acks != call->tx_top - call->tx_hard_ack) { call->cong_extra++; wake_up(&call->waitq); } goto out_no_clear_ca; } /* * 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 sk_buff *skb, *list = NULL; bool rot_last = false; int ix; u8 annotation; if (call->acks_lowest_nak == call->tx_hard_ack) { call->acks_lowest_nak = to; } else if (before_eq(call->acks_lowest_nak, to)) { summary->new_low_nack = true; call->acks_lowest_nak = to; } spin_lock(&call->lock); while (before(call->tx_hard_ack, to)) { call->tx_hard_ack++; ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK; skb = call->rxtx_buffer[ix]; annotation = call->rxtx_annotations[ix]; rxrpc_see_skb(skb, rxrpc_skb_rotated); call->rxtx_buffer[ix] = NULL; call->rxtx_annotations[ix] = 0; skb->next = list; list = skb; if (annotation & RXRPC_TX_ANNO_LAST) { set_bit(RXRPC_CALL_TX_LAST, &call->flags); rot_last = true; } if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK) summary->nr_rot_new_acks++; } spin_unlock(&call->lock); trace_rxrpc_transmit(call, (rot_last ? rxrpc_transmit_rotate_last : rxrpc_transmit_rotate)); wake_up(&call->waitq); while (list) { skb = list; list = skb->next; skb_mark_not_on_list(skb); rxrpc_free_skb(skb, rxrpc_skb_freed); } 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 bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun, const char *abort_why) { unsigned int state; ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags)); write_lock(&call->state_lock); state = call->state; switch (state) { case RXRPC_CALL_CLIENT_SEND_REQUEST: case RXRPC_CALL_CLIENT_AWAIT_REPLY: if (reply_begun) call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY; else call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY; break; case RXRPC_CALL_SERVER_AWAIT_ACK: __rxrpc_call_completed(call); state = call->state; break; default: goto bad_state; } write_unlock(&call->state_lock); if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY) trace_rxrpc_transmit(call, rxrpc_transmit_await_reply); else trace_rxrpc_transmit(call, rxrpc_transmit_end); _leave(" = ok"); return true; bad_state: write_unlock(&call->state_lock); kdebug("end_tx %s", rxrpc_call_states[call->state]); rxrpc_proto_abort(abort_why, call, call->tx_top); return false; } /* * 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) { spin_lock_bh(&call->lock); call->ackr_reason = 0; spin_unlock_bh(&call->lock); now = jiffies; timo = now + MAX_JIFFY_OFFSET; WRITE_ONCE(call->resend_at, timo); WRITE_ONCE(call->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("TXL", call, top); return false; } } if (!rxrpc_end_tx_phase(call, true, "ETD")) return false; call->tx_phase = false; return true; } /* * Scan a data packet to validate its structure and to work out how many * subpackets it contains. * * A jumbo packet is a collection of consecutive packets glued together with * little headers between that indicate how to change the initial header for * each subpacket. * * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but * the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any * size. */ static bool rxrpc_validate_data(struct sk_buff *skb) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); unsigned int offset = sizeof(struct rxrpc_wire_header); unsigned int len = skb->len; u8 flags = sp->hdr.flags; for (;;) { if (flags & RXRPC_REQUEST_ACK) __set_bit(sp->nr_subpackets, sp->rx_req_ack); sp->nr_subpackets++; if (!(flags & RXRPC_JUMBO_PACKET)) break; if (len - offset < RXRPC_JUMBO_SUBPKTLEN) goto protocol_error; if (flags & RXRPC_LAST_PACKET) goto protocol_error; offset += RXRPC_JUMBO_DATALEN; if (skb_copy_bits(skb, offset, &flags, 1) < 0) goto protocol_error; offset += sizeof(struct rxrpc_jumbo_header); } if (flags & RXRPC_LAST_PACKET) sp->rx_flags |= RXRPC_SKB_INCL_LAST; return true; protocol_error: return false; } /* * Handle reception of a duplicate packet. * * We have to take care to avoid an attack here whereby we're given a series of * jumbograms, each with a sequence number one before the preceding one and * filled up to maximum UDP size. If they never send us the first packet in * the sequence, they can cause us to have to hold on to around 2MiB of kernel * space until the call times out. * * We limit the space usage by only accepting three duplicate jumbo packets per * call. After that, we tell the other side we're no longer accepting jumbos * (that information is encoded in the ACK packet). */ static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq, bool is_jumbo, bool *_jumbo_bad) { /* Discard normal packets that are duplicates. */ if (is_jumbo) return; /* Skip jumbo subpackets that are duplicates. When we've had three or * more partially duplicate jumbo packets, we refuse to take any more * jumbos for this call. */ if (!*_jumbo_bad) { call->nr_jumbo_bad++; *_jumbo_bad = true; } } /* * 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); enum rxrpc_call_state state; unsigned int j, nr_subpackets, nr_unacked = 0; rxrpc_serial_t serial = sp->hdr.serial, ack_serial = serial; rxrpc_seq_t seq0 = sp->hdr.seq, hard_ack; bool immediate_ack = false, jumbo_bad = false; u8 ack = 0; _enter("{%u,%u},{%u,%u}", call->rx_hard_ack, call->rx_top, skb->len, seq0); _proto("Rx DATA %%%u { #%u f=%02x n=%u }", sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets); state = READ_ONCE(call->state); if (state >= RXRPC_CALL_COMPLETE) { rxrpc_free_skb(skb, rxrpc_skb_freed); return; } if (state == 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); } } spin_lock(&call->input_lock); /* Received data implicitly ACKs all of the request packets we sent * when we're acting as a client. */ if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST || state == RXRPC_CALL_CLIENT_AWAIT_REPLY) && !rxrpc_receiving_reply(call)) goto unlock; hard_ack = READ_ONCE(call->rx_hard_ack); nr_subpackets = sp->nr_subpackets; if (nr_subpackets > 1) { if (call->nr_jumbo_bad > 3) { ack = RXRPC_ACK_NOSPACE; ack_serial = serial; goto ack; } } for (j = 0; j < nr_subpackets; j++) { rxrpc_serial_t serial = sp->hdr.serial + j; rxrpc_seq_t seq = seq0 + j; unsigned int ix = seq & RXRPC_RXTX_BUFF_MASK; bool terminal = (j == nr_subpackets - 1); bool last = terminal && (sp->rx_flags & RXRPC_SKB_INCL_LAST); u8 flags, annotation = j; _proto("Rx DATA+%u %%%u { #%x t=%u l=%u }", j, serial, seq, terminal, last); if (last) { if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && seq != call->rx_top) { rxrpc_proto_abort("LSN", call, seq); goto unlock; } } else { if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && after_eq(seq, call->rx_top)) { rxrpc_proto_abort("LSA", call, seq); goto unlock; } } flags = 0; if (last) flags |= RXRPC_LAST_PACKET; if (!terminal) flags |= RXRPC_JUMBO_PACKET; if (test_bit(j, sp->rx_req_ack)) flags |= RXRPC_REQUEST_ACK; trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation); if (before_eq(seq, hard_ack)) { ack = RXRPC_ACK_DUPLICATE; ack_serial = serial; continue; } if (call->rxtx_buffer[ix]) { rxrpc_input_dup_data(call, seq, nr_subpackets > 1, &jumbo_bad); if (ack != RXRPC_ACK_DUPLICATE) { ack = RXRPC_ACK_DUPLICATE; ack_serial = serial; } immediate_ack = true; continue; } if (after(seq, hard_ack + call->rx_winsize)) { ack = RXRPC_ACK_EXCEEDS_WINDOW; ack_serial = serial; if (flags & RXRPC_JUMBO_PACKET) { if (!jumbo_bad) { call->nr_jumbo_bad++; jumbo_bad = true; } } goto ack; } if (flags & RXRPC_REQUEST_ACK && !ack) { ack = RXRPC_ACK_REQUESTED; ack_serial = serial; } if (after(seq0, call->ackr_highest_seq)) call->ackr_highest_seq = seq0; /* Queue the packet. We use a couple of memory barriers here as need * to make sure that rx_top is perceived to be set after the buffer * pointer and that the buffer pointer is set after the annotation and * the skb data. * * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window() * and also rxrpc_fill_out_ack(). */ if (!terminal) rxrpc_get_skb(skb, rxrpc_skb_got); call->rxtx_annotations[ix] = annotation; smp_wmb(); call->rxtx_buffer[ix] = skb; if (after(seq, call->rx_top)) { smp_store_release(&call->rx_top, seq); } else if (before(seq, call->rx_top)) { /* Send an immediate ACK if we fill in a hole */ if (!ack) { ack = RXRPC_ACK_DELAY; ack_serial = serial; } immediate_ack = true; } if (terminal) { /* From this point on, we're not allowed to touch the * packet any longer as its ref now belongs to the Rx * ring. */ skb = NULL; sp = NULL; } nr_unacked++; if (last) { set_bit(RXRPC_CALL_RX_LAST, &call->flags); if (!ack) { ack = RXRPC_ACK_DELAY; ack_serial = serial; } trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq); } else { trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq); } if (after_eq(seq, call->rx_expect_next)) { if (after(seq, call->rx_expect_next)) { _net("OOS %u > %u", seq, call->rx_expect_next); ack = RXRPC_ACK_OUT_OF_SEQUENCE; ack_serial = serial; } call->rx_expect_next = seq + 1; } if (!ack) ack_serial = serial; } ack: if (atomic_add_return(nr_unacked, &call->ackr_nr_unacked) > 2 && !ack) ack = RXRPC_ACK_IDLE; if (ack) rxrpc_propose_ACK(call, ack, ack_serial, immediate_ack, true, rxrpc_propose_ack_input_data); else rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial, false, true, rxrpc_propose_ack_input_data); trace_rxrpc_notify_socket(call->debug_id, serial); rxrpc_notify_socket(call); unlock: spin_unlock(&call->input_lock); rxrpc_free_skb(skb, rxrpc_skb_freed); _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 response to a ping that we sent to find out if we lost an ACK. * * If we got back a ping response that indicates a lower tx_top than what we * had at the time of the ping transmission, we adjudge all the DATA packets * sent between the response tx_top and the ping-time tx_top to have been lost. */ static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call) { rxrpc_seq_t top, bottom, seq; bool resend = false; spin_lock_bh(&call->lock); bottom = call->tx_hard_ack + 1; top = call->acks_lost_top; if (before(bottom, top)) { for (seq = bottom; before_eq(seq, top); seq++) { int ix = seq & RXRPC_RXTX_BUFF_MASK; u8 annotation = call->rxtx_annotations[ix]; u8 anno_type = annotation & RXRPC_TX_ANNO_MASK; if (anno_type != RXRPC_TX_ANNO_UNACK) continue; annotation &= ~RXRPC_TX_ANNO_MASK; annotation |= RXRPC_TX_ANNO_RETRANS; call->rxtx_annotations[ix] = annotation; resend = true; } } spin_unlock_bh(&call->lock); if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events)) rxrpc_queue_call(call); } /* * Process a ping response. */ static void rxrpc_input_ping_response(struct rxrpc_call *call, ktime_t resp_time, rxrpc_serial_t acked_serial, rxrpc_serial_t ack_serial) { if (acked_serial == call->acks_lost_ping) rxrpc_input_check_for_lost_ack(call); } /* * 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); _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }", sp->hdr.serial, ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU), rwind, ntohl(ackinfo->jumbo_max)); if (rwind > RXRPC_RXTX_BUFF_SIZE - 1) rwind = RXRPC_RXTX_BUFF_SIZE - 1; 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_bh(&peer->lock); peer->maxdata = mtu; peer->mtu = mtu + peer->hdrsize; spin_unlock_bh(&peer->lock); _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata); } 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) { int ix; u8 annotation, anno_type; for (; nr_acks > 0; nr_acks--, seq++) { ix = seq & RXRPC_RXTX_BUFF_MASK; annotation = call->rxtx_annotations[ix]; anno_type = annotation & RXRPC_TX_ANNO_MASK; annotation &= ~RXRPC_TX_ANNO_MASK; switch (*acks++) { case RXRPC_ACK_TYPE_ACK: summary->nr_acks++; if (anno_type == RXRPC_TX_ANNO_ACK) continue; summary->nr_new_acks++; call->rxtx_annotations[ix] = RXRPC_TX_ANNO_ACK | annotation; break; case RXRPC_ACK_TYPE_NACK: if (!summary->nr_nacks && call->acks_lowest_nak != seq) { call->acks_lowest_nak = seq; summary->new_low_nack = true; } summary->nr_nacks++; if (anno_type == RXRPC_TX_ANNO_NAK) continue; summary->nr_new_nacks++; if (anno_type == RXRPC_TX_ANNO_RETRANS) continue; call->rxtx_annotations[ix] = RXRPC_TX_ANNO_NAK | annotation; break; default: return rxrpc_proto_abort("SFT", call, 0); } } } /* * 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_skb_priv *sp = rxrpc_skb(skb); union { struct rxrpc_ackpacket ack; struct rxrpc_ackinfo info; u8 acks[RXRPC_MAXACKS]; } buf; 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, &buf.ack, sizeof(buf.ack)) < 0) { _debug("extraction failure"); return rxrpc_proto_abort("XAK", call, 0); } offset += sizeof(buf.ack); ack_serial = sp->hdr.serial; acked_serial = ntohl(buf.ack.serial); first_soft_ack = ntohl(buf.ack.firstPacket); prev_pkt = ntohl(buf.ack.previousPacket); hard_ack = first_soft_ack - 1; nr_acks = buf.ack.nAcks; summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ? buf.ack.reason : RXRPC_ACK__INVALID); trace_rxrpc_rx_ack(call, ack_serial, acked_serial, first_soft_ack, prev_pkt, summary.ack_reason, nr_acks); switch (buf.ack.reason) { case RXRPC_ACK_PING_RESPONSE: rxrpc_input_ping_response(call, skb->tstamp, acked_serial, ack_serial); 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 (buf.ack.reason == RXRPC_ACK_PING) { _proto("Rx ACK %%%u PING Request", ack_serial); rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial, true, true, rxrpc_propose_ack_respond_to_ping); } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) { rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, ack_serial, true, true, 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(buf.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(buf.ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) && first_soft_ack == 1 && prev_pkt == 0 && call->tx_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; } buf.info.rxMTU = 0; ioffset = offset + nr_acks + 3; if (skb->len >= ioffset + sizeof(buf.info) && skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0) return rxrpc_proto_abort("XAI", call, 0); spin_lock(&call->input_lock); /* Discard any out-of-order or duplicate ACKs (inside 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 out; } call->acks_latest_ts = skb->tstamp; call->acks_first_seq = first_soft_ack; call->acks_prev_seq = prev_pkt; /* Parse rwind and mtu sizes if provided. */ if (buf.info.rxMTU) rxrpc_input_ackinfo(call, skb, &buf.info); if (first_soft_ack == 0) { rxrpc_proto_abort("AK0", call, 0); goto out; } /* Ignore ACKs unless we are or have just been transmitting. */ switch (READ_ONCE(call->state)) { 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 out; } if (before(hard_ack, call->tx_hard_ack) || after(hard_ack, call->tx_top)) { rxrpc_proto_abort("AKW", call, 0); goto out; } if (nr_acks > call->tx_top - hard_ack) { rxrpc_proto_abort("AKN", call, 0); goto out; } if (after(hard_ack, call->tx_hard_ack)) { if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) { rxrpc_end_tx_phase(call, false, "ETA"); goto out; } } if (nr_acks > 0) { if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) { rxrpc_proto_abort("XSA", call, 0); goto out; } rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks, &summary); } if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] & RXRPC_TX_ANNO_LAST && summary.nr_acks == call->tx_top - hard_ack && rxrpc_is_client_call(call)) rxrpc_propose_ACK(call, RXRPC_ACK_PING, ack_serial, false, true, rxrpc_propose_ack_ping_for_lost_reply); rxrpc_congestion_management(call, skb, &summary, acked_serial); out: spin_unlock(&call->input_lock); } /* * Process an ACKALL packet. */ static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb) { struct rxrpc_ack_summary summary = { 0 }; struct rxrpc_skb_priv *sp = rxrpc_skb(skb); _proto("Rx ACKALL %%%u", sp->hdr.serial); spin_lock(&call->input_lock); if (rxrpc_rotate_tx_window(call, call->tx_top, &summary)) rxrpc_end_tx_phase(call, false, "ETL"); spin_unlock(&call->input_lock); } /* * 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); __be32 wtmp; u32 abort_code = RX_CALL_DEAD; _enter(""); if (skb->len >= 4 && skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), &wtmp, sizeof(wtmp)) >= 0) abort_code = ntohl(wtmp); trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code); _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code); rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, abort_code, -ECONNABORTED); } /* * Process an incoming call packet. */ static 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); 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: rxrpc_input_data(call, skb); goto no_free; case RXRPC_PACKET_TYPE_ACK: rxrpc_input_ack(call, skb); break; case RXRPC_PACKET_TYPE_BUSY: _proto("Rx BUSY %%%u", sp->hdr.serial); /* 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. */ break; case RXRPC_PACKET_TYPE_ABORT: rxrpc_input_abort(call, skb); break; case RXRPC_PACKET_TYPE_ACKALL: rxrpc_input_ackall(call, skb); break; default: break; } rxrpc_free_skb(skb, rxrpc_skb_freed); no_free: _leave(""); } /* * 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. */ static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx, struct rxrpc_connection *conn, struct rxrpc_call *call) { switch (READ_ONCE(call->state)) { case RXRPC_CALL_SERVER_AWAIT_ACK: rxrpc_call_completed(call); fallthrough; case RXRPC_CALL_COMPLETE: break; default: if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) { set_bit(RXRPC_CALL_EV_ABORT, &call->events); rxrpc_queue_call(call); } trace_rxrpc_improper_term(call); break; } spin_lock(&rx->incoming_lock); __rxrpc_disconnect_call(conn, call); spin_unlock(&rx->incoming_lock); } /* * post connection-level events to the connection * - this includes challenges, responses, some aborts and call terminal packet * retransmission. */ static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn, struct sk_buff *skb) { _enter("%p,%p", conn, skb); skb_queue_tail(&conn->rx_queue, skb); rxrpc_queue_conn(conn); } /* * post endpoint-level events to the local endpoint * - this includes debug and version messages */ static void rxrpc_post_packet_to_local(struct rxrpc_local *local, struct sk_buff *skb) { _enter("%p,%p", local, skb); if (rxrpc_get_local_maybe(local)) { skb_queue_tail(&local->event_queue, skb); rxrpc_queue_local(local); } else { rxrpc_free_skb(skb, rxrpc_skb_freed); } } /* * put a packet up for transport-level abort */ static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb) { CHECK_SLAB_OKAY(&local->usage); if (rxrpc_get_local_maybe(local)) { skb_queue_tail(&local->reject_queue, skb); rxrpc_queue_local(local); } else { rxrpc_free_skb(skb, rxrpc_skb_freed); } } /* * Extract the wire header from a packet and translate the byte order. */ static noinline int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb) { struct rxrpc_wire_header whdr; /* dig out the RxRPC connection details */ if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) { trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, tracepoint_string("bad_hdr")); return -EBADMSG; } memset(sp, 0, sizeof(*sp)); sp->hdr.epoch = ntohl(whdr.epoch); sp->hdr.cid = ntohl(whdr.cid); sp->hdr.callNumber = ntohl(whdr.callNumber); sp->hdr.seq = ntohl(whdr.seq); sp->hdr.serial = ntohl(whdr.serial); sp->hdr.flags = whdr.flags; sp->hdr.type = whdr.type; sp->hdr.userStatus = whdr.userStatus; sp->hdr.securityIndex = whdr.securityIndex; sp->hdr._rsvd = ntohs(whdr._rsvd); sp->hdr.serviceId = ntohs(whdr.serviceId); return 0; } /* * handle data received on the local endpoint * - may be called in interrupt context * * [!] Note that as this is called from the encap_rcv hook, the socket is not * held locked by the caller and nothing prevents sk_user_data on the UDP from * being cleared in the middle of processing this function. * * Called with the RCU read lock held from the IP layer via UDP. */ int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb) { struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk); struct rxrpc_connection *conn; struct rxrpc_channel *chan; struct rxrpc_call *call = NULL; struct rxrpc_skb_priv *sp; struct rxrpc_peer *peer = NULL; struct rxrpc_sock *rx = NULL; unsigned int channel; _enter("%p", udp_sk); if (unlikely(!local)) { kfree_skb(skb); return 0; } if (skb->tstamp == 0) skb->tstamp = ktime_get_real(); rxrpc_new_skb(skb, rxrpc_skb_received); skb_pull(skb, sizeof(struct udphdr)); /* The UDP protocol already released all skb resources; * we are free to add our own data there. */ sp = rxrpc_skb(skb); /* dig out the RxRPC connection details */ if (rxrpc_extract_header(sp, skb) < 0) goto bad_message; if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) { static int lose; if ((lose++ & 7) == 7) { trace_rxrpc_rx_lose(sp); rxrpc_free_skb(skb, rxrpc_skb_lost); return 0; } } if (skb->tstamp == 0) skb->tstamp = ktime_get_real(); trace_rxrpc_rx_packet(sp); switch (sp->hdr.type) { case RXRPC_PACKET_TYPE_VERSION: if (rxrpc_to_client(sp)) goto discard; rxrpc_post_packet_to_local(local, skb); goto out; case RXRPC_PACKET_TYPE_BUSY: if (rxrpc_to_server(sp)) goto discard; fallthrough; case RXRPC_PACKET_TYPE_ACK: case RXRPC_PACKET_TYPE_ACKALL: if (sp->hdr.callNumber == 0) goto bad_message; fallthrough; case RXRPC_PACKET_TYPE_ABORT: break; case RXRPC_PACKET_TYPE_DATA: if (sp->hdr.callNumber == 0 || sp->hdr.seq == 0) goto bad_message; if (!rxrpc_validate_data(skb)) goto bad_message; /* Unshare the packet so that it can be modified for in-place * decryption. */ if (sp->hdr.securityIndex != 0) { struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC); if (!nskb) { rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem); goto out; } if (nskb != skb) { rxrpc_eaten_skb(skb, rxrpc_skb_received); skb = nskb; rxrpc_new_skb(skb, rxrpc_skb_unshared); sp = rxrpc_skb(skb); } } break; case RXRPC_PACKET_TYPE_CHALLENGE: if (rxrpc_to_server(sp)) goto discard; break; case RXRPC_PACKET_TYPE_RESPONSE: if (rxrpc_to_client(sp)) goto discard; break; /* Packet types 9-11 should just be ignored. */ case RXRPC_PACKET_TYPE_PARAMS: case RXRPC_PACKET_TYPE_10: case RXRPC_PACKET_TYPE_11: goto discard; default: _proto("Rx Bad Packet Type %u", sp->hdr.type); goto bad_message; } if (sp->hdr.serviceId == 0) goto bad_message; if (rxrpc_to_server(sp)) { /* Weed out packets to services we're not offering. Packets * that would begin a call are explicitly rejected and the rest * are just discarded. */ rx = rcu_dereference(local->service); if (!rx || (sp->hdr.serviceId != rx->srx.srx_service && sp->hdr.serviceId != rx->second_service)) { if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA && sp->hdr.seq == 1) goto unsupported_service; goto discard; } } conn = rxrpc_find_connection_rcu(local, skb, &peer); if (conn) { if (sp->hdr.securityIndex != conn->security_ix) goto wrong_security; if (sp->hdr.serviceId != conn->service_id) { int old_id; if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) goto reupgrade; old_id = cmpxchg(&conn->service_id, conn->params.service_id, sp->hdr.serviceId); if (old_id != conn->params.service_id && old_id != sp->hdr.serviceId) goto reupgrade; } if (sp->hdr.callNumber == 0) { /* Connection-level packet */ _debug("CONN %p {%d}", conn, conn->debug_id); rxrpc_post_packet_to_conn(conn, skb); goto out; } if ((int)sp->hdr.serial - (int)conn->hi_serial > 0) conn->hi_serial = sp->hdr.serial; /* Call-bound packets are routed by connection channel. */ channel = sp->hdr.cid & RXRPC_CHANNELMASK; chan = &conn->channels[channel]; /* Ignore really old calls */ if (sp->hdr.callNumber < chan->last_call) goto discard; if (sp->hdr.callNumber == chan->last_call) { if (chan->call || sp->hdr.type == RXRPC_PACKET_TYPE_ABORT) goto discard; /* For the previous service call, if completed * successfully, we discard all further packets. */ if (rxrpc_conn_is_service(conn) && chan->last_type == RXRPC_PACKET_TYPE_ACK) goto discard; /* But otherwise we need to retransmit the final packet * from data cached in the connection record. */ if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) trace_rxrpc_rx_data(chan->call_debug_id, sp->hdr.seq, sp->hdr.serial, sp->hdr.flags, 0); rxrpc_post_packet_to_conn(conn, skb); goto out; } call = rcu_dereference(chan->call); if (sp->hdr.callNumber > chan->call_id) { if (rxrpc_to_client(sp)) goto reject_packet; if (call) rxrpc_input_implicit_end_call(rx, conn, call); call = NULL; } if (call) { if (sp->hdr.serviceId != call->service_id) call->service_id = 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); } } if (!call || atomic_read(&call->usage) == 0) { if (rxrpc_to_client(sp) || sp->hdr.type != RXRPC_PACKET_TYPE_DATA) goto bad_message; if (sp->hdr.seq != 1) goto discard; call = rxrpc_new_incoming_call(local, rx, skb); if (!call) goto reject_packet; } /* Process a call packet; this either discards or passes on the ref * elsewhere. */ rxrpc_input_call_packet(call, skb); goto out; discard: rxrpc_free_skb(skb, rxrpc_skb_freed); out: trace_rxrpc_rx_done(0, 0); return 0; wrong_security: trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, RXKADINCONSISTENCY, EBADMSG); skb->priority = RXKADINCONSISTENCY; goto post_abort; unsupported_service: trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, RX_INVALID_OPERATION, EOPNOTSUPP); skb->priority = RX_INVALID_OPERATION; goto post_abort; reupgrade: trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, RX_PROTOCOL_ERROR, EBADMSG); goto protocol_error; bad_message: trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, RX_PROTOCOL_ERROR, EBADMSG); protocol_error: skb->priority = RX_PROTOCOL_ERROR; post_abort: skb->mark = RXRPC_SKB_MARK_REJECT_ABORT; reject_packet: trace_rxrpc_rx_done(skb->mark, skb->priority); rxrpc_reject_packet(local, skb); _leave(" [badmsg]"); return 0; }