/* RxRPC packet reception * * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #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) { enum rxrpc_congest_change change = rxrpc_cong_no_change; struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 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_usage == 0) goto out; if (ktime_before(skb->tstamp, ktime_add_ns(call->cong_tstamp, call->peer->rtt))) 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, sp->hdr.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; } /* * Ping the other end to fill our RTT cache and to retrieve the rwind * and MTU parameters. */ static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb, int skew) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); ktime_t now = skb->tstamp; if (call->peer->rtt_usage < 3 || ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now)) rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial, true, true, rxrpc_propose_ack_ping_for_params); } /* * Apply a hard ACK by advancing the Tx window. */ static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to, struct rxrpc_ack_summary *summary) { struct sk_buff *skb, *list = NULL; 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_tx_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); if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK) summary->nr_rot_new_acks++; } spin_unlock(&call->lock); trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ? rxrpc_transmit_rotate_last : rxrpc_transmit_rotate)); wake_up(&call->waitq); while (list) { skb = list; list = skb->next; skb->next = NULL; rxrpc_free_skb(skb, rxrpc_skb_tx_freed); } } /* * 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) { ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags)); write_lock(&call->state_lock); switch (call->state) { case RXRPC_CALL_CLIENT_SEND_REQUEST: case RXRPC_CALL_CLIENT_AWAIT_REPLY: if (reply_begun) call->state = RXRPC_CALL_CLIENT_RECV_REPLY; else call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY; break; case RXRPC_CALL_SERVER_AWAIT_ACK: __rxrpc_call_completed(call); rxrpc_notify_socket(call); break; default: goto bad_state; } write_unlock(&call->state_lock); if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) { rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, false, true, rxrpc_propose_ack_client_tx_end); 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 }; rxrpc_seq_t top = READ_ONCE(call->tx_top); if (call->ackr_reason) { spin_lock_bh(&call->lock); call->ackr_reason = 0; call->resend_at = call->expire_at; call->ack_at = call->expire_at; spin_unlock_bh(&call->lock); rxrpc_set_timer(call, rxrpc_timer_init_for_reply); } if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) rxrpc_rotate_tx_window(call, top, &summary); if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) { 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 jumbo 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_jumbo(struct sk_buff *skb) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); unsigned int offset = sp->offset; unsigned int len = skb->len; int nr_jumbo = 1; u8 flags = sp->hdr.flags; do { nr_jumbo++; 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); } while (flags & RXRPC_JUMBO_PACKET); sp->nr_jumbo = nr_jumbo; 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, u8 annotation, bool *_jumbo_bad) { /* Discard normal packets that are duplicates. */ if (annotation == 0) 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. */ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb, u16 skew) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); unsigned int offset = sp->offset; unsigned int ix; rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0; rxrpc_seq_t seq = sp->hdr.seq, hard_ack; bool immediate_ack = false, jumbo_bad = false, queued; u16 len; u8 ack = 0, flags, annotation = 0; _enter("{%u,%u},{%u,%u}", call->rx_hard_ack, call->rx_top, skb->len, seq); _proto("Rx DATA %%%u { #%u f=%02x }", sp->hdr.serial, seq, sp->hdr.flags); if (call->state >= RXRPC_CALL_COMPLETE) return; /* Received data implicitly ACKs all of the request packets we sent * when we're acting as a client. */ if ((call->state == RXRPC_CALL_CLIENT_SEND_REQUEST || call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) && !rxrpc_receiving_reply(call)) return; call->ackr_prev_seq = seq; hard_ack = READ_ONCE(call->rx_hard_ack); if (after(seq, hard_ack + call->rx_winsize)) { ack = RXRPC_ACK_EXCEEDS_WINDOW; ack_serial = serial; goto ack; } flags = sp->hdr.flags; if (flags & RXRPC_JUMBO_PACKET) { if (call->nr_jumbo_bad > 3) { ack = RXRPC_ACK_NOSPACE; ack_serial = serial; goto ack; } annotation = 1; } next_subpacket: queued = false; ix = seq & RXRPC_RXTX_BUFF_MASK; len = skb->len; if (flags & RXRPC_JUMBO_PACKET) len = RXRPC_JUMBO_DATALEN; if (flags & RXRPC_LAST_PACKET) { if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && seq != call->rx_top) return rxrpc_proto_abort("LSN", call, seq); } else { if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) && after_eq(seq, call->rx_top)) return rxrpc_proto_abort("LSA", call, seq); } if (before_eq(seq, hard_ack)) { ack = RXRPC_ACK_DUPLICATE; ack_serial = serial; goto skip; } if (flags & RXRPC_REQUEST_ACK && !ack) { ack = RXRPC_ACK_REQUESTED; ack_serial = serial; } if (call->rxtx_buffer[ix]) { rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad); if (ack != RXRPC_ACK_DUPLICATE) { ack = RXRPC_ACK_DUPLICATE; ack_serial = serial; } immediate_ack = true; goto skip; } /* 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(). */ rxrpc_get_skb(skb, rxrpc_skb_rx_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 (flags & RXRPC_LAST_PACKET) { set_bit(RXRPC_CALL_RX_LAST, &call->flags); trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq); } else { trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq); } queued = true; 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; } skip: offset += len; if (flags & RXRPC_JUMBO_PACKET) { if (skb_copy_bits(skb, offset, &flags, 1) < 0) return rxrpc_proto_abort("XJF", call, seq); offset += sizeof(struct rxrpc_jumbo_header); seq++; serial++; annotation++; if (flags & RXRPC_JUMBO_PACKET) annotation |= RXRPC_RX_ANNO_JLAST; if (after(seq, hard_ack + call->rx_winsize)) { ack = RXRPC_ACK_EXCEEDS_WINDOW; ack_serial = serial; if (!jumbo_bad) { call->nr_jumbo_bad++; jumbo_bad = true; } goto ack; } _proto("Rx DATA Jumbo %%%u", serial); goto next_subpacket; } if (queued && flags & RXRPC_LAST_PACKET && !ack) { ack = RXRPC_ACK_DELAY; ack_serial = serial; } ack: if (ack) rxrpc_propose_ACK(call, ack, skew, ack_serial, immediate_ack, true, rxrpc_propose_ack_input_data); if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1) rxrpc_notify_socket(call); _leave(" [queued]"); } /* * Process a requested ACK. */ static void rxrpc_input_requested_ack(struct rxrpc_call *call, ktime_t resp_time, rxrpc_serial_t orig_serial, rxrpc_serial_t ack_serial) { struct rxrpc_skb_priv *sp; struct sk_buff *skb; ktime_t sent_at; int ix; for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) { skb = call->rxtx_buffer[ix]; if (!skb) continue; sp = rxrpc_skb(skb); if (sp->hdr.serial != orig_serial) continue; smp_rmb(); sent_at = skb->tstamp; goto found; } return; found: rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack, orig_serial, ack_serial, sent_at, resp_time); } /* * Process a ping response. */ static void rxrpc_input_ping_response(struct rxrpc_call *call, ktime_t resp_time, rxrpc_serial_t orig_serial, rxrpc_serial_t ack_serial) { rxrpc_serial_t ping_serial; ktime_t ping_time; ping_time = call->ackr_ping_time; smp_rmb(); ping_serial = call->ackr_ping; if (!test_bit(RXRPC_CALL_PINGING, &call->flags) || before(orig_serial, ping_serial)) return; clear_bit(RXRPC_CALL_PINGING, &call->flags); if (after(orig_serial, ping_serial)) return; rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response, orig_serial, ack_serial, ping_time, resp_time); } /* * 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; 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; call->tx_winsize = 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); } } /* * 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); } } } /* * 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, u16 skew) { 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 acked_serial; rxrpc_seq_t first_soft_ack, hard_ack; int nr_acks, offset; _enter(""); if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) { _debug("extraction failure"); return rxrpc_proto_abort("XAK", call, 0); } sp->offset += sizeof(buf.ack); acked_serial = ntohl(buf.ack.serial); first_soft_ack = ntohl(buf.ack.firstPacket); 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, first_soft_ack, summary.ack_reason, nr_acks); _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }", sp->hdr.serial, ntohs(buf.ack.maxSkew), first_soft_ack, ntohl(buf.ack.previousPacket), acked_serial, rxrpc_ack_names[summary.ack_reason], buf.ack.nAcks); if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE) rxrpc_input_ping_response(call, skb->tstamp, acked_serial, sp->hdr.serial); if (buf.ack.reason == RXRPC_ACK_REQUESTED) rxrpc_input_requested_ack(call, skb->tstamp, acked_serial, sp->hdr.serial); if (buf.ack.reason == RXRPC_ACK_PING) { _proto("Rx ACK %%%u PING Request", sp->hdr.serial); rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE, skew, sp->hdr.serial, true, true, rxrpc_propose_ack_respond_to_ping); } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) { rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, skew, sp->hdr.serial, true, true, rxrpc_propose_ack_respond_to_ack); } offset = sp->offset + nr_acks + 3; if (skb->len >= offset + sizeof(buf.info)) { if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0) return rxrpc_proto_abort("XAI", call, 0); rxrpc_input_ackinfo(call, skb, &buf.info); } if (first_soft_ack == 0) return rxrpc_proto_abort("AK0", call, 0); /* Ignore ACKs unless we are or have just been transmitting. */ switch (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: return; } /* Discard any out-of-order or duplicate ACKs. */ if (before_eq(sp->hdr.serial, call->acks_latest)) { _debug("discard ACK %d <= %d", sp->hdr.serial, call->acks_latest); return; } call->acks_latest_ts = skb->tstamp; call->acks_latest = sp->hdr.serial; if (before(hard_ack, call->tx_hard_ack) || after(hard_ack, call->tx_top)) return rxrpc_proto_abort("AKW", call, 0); if (nr_acks > call->tx_top - hard_ack) return rxrpc_proto_abort("AKN", call, 0); if (after(hard_ack, call->tx_hard_ack)) rxrpc_rotate_tx_window(call, hard_ack, &summary); if (nr_acks > 0) { if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0) return rxrpc_proto_abort("XSA", call, 0); rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks, &summary); } if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) { rxrpc_end_tx_phase(call, false, "ETA"); return; } if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] & RXRPC_TX_ANNO_LAST && summary.nr_acks == call->tx_top - hard_ack) rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial, false, true, rxrpc_propose_ack_ping_for_lost_reply); return rxrpc_congestion_management(call, skb, &summary); } /* * 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); rxrpc_rotate_tx_window(call, call->tx_top, &summary); if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) rxrpc_end_tx_phase(call, false, "ETL"); } /* * Process an ABORT packet. */ 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, sp->offset, &wtmp, sizeof(wtmp)) >= 0) abort_code = ntohl(wtmp); _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code); if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, abort_code, ECONNABORTED)) rxrpc_notify_socket(call); } /* * Process an incoming call packet. */ static void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb, u16 skew) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); _enter("%p,%p", call, skb); switch (sp->hdr.type) { case RXRPC_PACKET_TYPE_DATA: rxrpc_input_data(call, skb, skew); break; case RXRPC_PACKET_TYPE_ACK: rxrpc_input_ack(call, skb, skew); 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: _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial); break; } _leave(""); } /* * 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); skb_queue_tail(&local->event_queue, skb); rxrpc_queue_local(local); } /* * 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); skb_queue_tail(&local->reject_queue, skb); rxrpc_queue_local(local); } /* * 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) 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); sp->offset = sizeof(whdr); return 0; } /* * handle data received on the local endpoint * - may be called in interrupt context * * The socket is locked by the caller and this prevents the socket from being * shut down and the local endpoint from going away, thus sk_user_data will not * be cleared until this function returns. */ void rxrpc_data_ready(struct sock *udp_sk) { struct rxrpc_connection *conn; struct rxrpc_channel *chan; struct rxrpc_call *call; struct rxrpc_skb_priv *sp; struct rxrpc_local *local = udp_sk->sk_user_data; struct sk_buff *skb; unsigned int channel; int ret, skew; _enter("%p", udp_sk); ASSERT(!irqs_disabled()); skb = skb_recv_datagram(udp_sk, 0, 1, &ret); if (!skb) { if (ret == -EAGAIN) return; _debug("UDP socket error %d", ret); return; } rxrpc_new_skb(skb, rxrpc_skb_rx_received); _net("recv skb %p", skb); /* we'll probably need to checksum it (didn't call sock_recvmsg) */ if (skb_checksum_complete(skb)) { rxrpc_free_skb(skb, rxrpc_skb_rx_freed); __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0); _leave(" [CSUM failed]"); return; } __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0); /* The socket buffer we have is owned by UDP, with UDP's data all over * it, but we really want our own data there. */ skb_orphan(skb); 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_lose_skb(skb, rxrpc_skb_rx_lost); return; } } trace_rxrpc_rx_packet(sp); _net("Rx RxRPC %s ep=%x call=%x:%x", sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient", sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber); if (sp->hdr.type >= RXRPC_N_PACKET_TYPES || !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) { _proto("Rx Bad Packet Type %u", sp->hdr.type); goto bad_message; } switch (sp->hdr.type) { case RXRPC_PACKET_TYPE_VERSION: rxrpc_post_packet_to_local(local, skb); goto out; case RXRPC_PACKET_TYPE_BUSY: if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) goto discard; case RXRPC_PACKET_TYPE_DATA: if (sp->hdr.callNumber == 0) goto bad_message; if (sp->hdr.flags & RXRPC_JUMBO_PACKET && !rxrpc_validate_jumbo(skb)) goto bad_message; break; } rcu_read_lock(); conn = rxrpc_find_connection_rcu(local, skb); if (conn) { if (sp->hdr.securityIndex != conn->security_ix) goto wrong_security; 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_unlock; } /* Note the serial number skew here */ skew = (int)sp->hdr.serial - (int)conn->hi_serial; if (skew >= 0) { if (skew > 0) conn->hi_serial = sp->hdr.serial; } else { skew = -skew; skew = min(skew, 65535); } /* 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_unlock; if (sp->hdr.callNumber == chan->last_call) { /* 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 || sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)) goto discard_unlock; /* But otherwise we need to retransmit the final packet from * data cached in the connection record. */ rxrpc_post_packet_to_conn(conn, skb); goto out_unlock; } call = rcu_dereference(chan->call); } else { skew = 0; call = NULL; } if (!call || atomic_read(&call->usage) == 0) { if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) || sp->hdr.callNumber == 0 || sp->hdr.type != RXRPC_PACKET_TYPE_DATA) goto bad_message_unlock; if (sp->hdr.seq != 1) goto discard_unlock; call = rxrpc_new_incoming_call(local, conn, skb); if (!call) { rcu_read_unlock(); goto reject_packet; } rxrpc_send_ping(call, skb, skew); } rxrpc_input_call_packet(call, skb, skew); goto discard_unlock; discard_unlock: rcu_read_unlock(); discard: rxrpc_free_skb(skb, rxrpc_skb_rx_freed); out: trace_rxrpc_rx_done(0, 0); return; out_unlock: rcu_read_unlock(); goto out; wrong_security: rcu_read_unlock(); trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, RXKADINCONSISTENCY, EBADMSG); skb->priority = RXKADINCONSISTENCY; goto post_abort; bad_message_unlock: rcu_read_unlock(); bad_message: trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq, RX_PROTOCOL_ERROR, EBADMSG); skb->priority = RX_PROTOCOL_ERROR; post_abort: skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT; reject_packet: trace_rxrpc_rx_done(skb->mark, skb->priority); rxrpc_reject_packet(local, skb); _leave(" [badmsg]"); }