/* * Copyright (c) 2016 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vppinfra/sparse_vec.h> #include <vnet/tcp/tcp_packet.h> #include <vnet/tcp/tcp.h> #include <vnet/session/session.h> #include <math.h> static char *tcp_error_strings[] = { #define tcp_error(n,s) s, #include <vnet/tcp/tcp_error.def> #undef tcp_error }; /* All TCP nodes have the same outgoing arcs */ #define foreach_tcp_state_next \ _ (DROP, "error-drop") \ _ (TCP4_OUTPUT, "tcp4-output") \ _ (TCP6_OUTPUT, "tcp6-output") typedef enum _tcp_established_next { #define _(s,n) TCP_ESTABLISHED_NEXT_##s, foreach_tcp_state_next #undef _ TCP_ESTABLISHED_N_NEXT, } tcp_established_next_t; typedef enum _tcp_rcv_process_next { #define _(s,n) TCP_RCV_PROCESS_NEXT_##s, foreach_tcp_state_next #undef _ TCP_RCV_PROCESS_N_NEXT, } tcp_rcv_process_next_t; typedef enum _tcp_syn_sent_next { #define _(s,n) TCP_SYN_SENT_NEXT_##s, foreach_tcp_state_next #undef _ TCP_SYN_SENT_N_NEXT, } tcp_syn_sent_next_t; typedef enum _tcp_listen_next { #define _(s,n) TCP_LISTEN_NEXT_##s, foreach_tcp_state_next #undef _ TCP_LISTEN_N_NEXT, } tcp_listen_next_t; /* Generic, state independent indices */ typedef enum _tcp_state_next { #define _(s,n) TCP_NEXT_##s, foreach_tcp_state_next #undef _ TCP_STATE_N_NEXT, } tcp_state_next_t; #define tcp_next_output(is_ip4) (is_ip4 ? TCP_NEXT_TCP4_OUTPUT \ : TCP_NEXT_TCP6_OUTPUT) vlib_node_registration_t tcp4_established_node; vlib_node_registration_t tcp6_established_node; /** * Validate segment sequence number. As per RFC793: * * Segment Receive Test * Length Window * ------- ------- ------------------------------------------- * 0 0 SEG.SEQ = RCV.NXT * 0 >0 RCV.NXT =< SEG.SEQ < RCV.NXT+RCV.WND * >0 0 not acceptable * >0 >0 RCV.NXT =< SEG.SEQ < RCV.NXT+RCV.WND * or RCV.NXT =< SEG.SEQ+SEG.LEN-1 < RCV.NXT+RCV.WND * * This ultimately consists in checking if segment falls within the window. * The one important difference compared to RFC793 is that we use rcv_las, * or the rcv_nxt at last ack sent instead of rcv_nxt since that's the * peer's reference when computing our receive window. * * This: * seq_leq (end_seq, tc->rcv_las + tc->rcv_wnd) && seq_geq (seq, tc->rcv_las) * however, is too strict when we have retransmits. Instead we just check that * the seq is not beyond the right edge and that the end of the segment is not * less than the left edge. * * N.B. rcv_nxt and rcv_wnd are both updated in this node if acks are sent, so * use rcv_nxt in the right edge window test instead of rcv_las. * */ always_inline u8 tcp_segment_in_rcv_wnd (tcp_connection_t * tc, u32 seq, u32 end_seq) { return (seq_geq (end_seq, tc->rcv_las) && seq_leq (seq, tc->rcv_nxt + tc->rcv_wnd)); } void tcp_options_parse (tcp_header_t * th, tcp_options_t * to) { const u8 *data; u8 opt_len, opts_len, kind; int j; sack_block_t b; opts_len = (tcp_doff (th) << 2) - sizeof (tcp_header_t); data = (const u8 *) (th + 1); /* Zero out all flags but those set in SYN */ to->flags &= (TCP_OPTS_FLAG_SACK_PERMITTED | TCP_OPTS_FLAG_WSCALE); for (; opts_len > 0; opts_len -= opt_len, data += opt_len) { kind = data[0]; /* Get options length */ if (kind == TCP_OPTION_EOL) break; else if (kind == TCP_OPTION_NOOP) opt_len = 1; else { /* broken options */ if (opts_len < 2) break; opt_len = data[1]; /* weird option length */ if (opt_len < 2 || opt_len > opts_len) break; } /* Parse options */ switch (kind) { case TCP_OPTION_MSS: if ((opt_len == TCP_OPTION_LEN_MSS) && tcp_syn (th)) { to->flags |= TCP_OPTS_FLAG_MSS; to->mss = clib_net_to_host_u16 (*(u16 *) (data + 2)); } break; case TCP_OPTION_WINDOW_SCALE: if ((opt_len == TCP_OPTION_LEN_WINDOW_SCALE) && tcp_syn (th)) { to->flags |= TCP_OPTS_FLAG_WSCALE; to->wscale = data[2]; if (to->wscale > TCP_MAX_WND_SCALE) { clib_warning ("Illegal window scaling value: %d", to->wscale); to->wscale = TCP_MAX_WND_SCALE; } } break; case TCP_OPTION_TIMESTAMP: if (opt_len == TCP_OPTION_LEN_TIMESTAMP) { to->flags |= TCP_OPTS_FLAG_TSTAMP; to->tsval = clib_net_to_host_u32 (*(u32 *) (data + 2)); to->tsecr = clib_net_to_host_u32 (*(u32 *) (data + 6)); } break; case TCP_OPTION_SACK_PERMITTED: if (opt_len == TCP_OPTION_LEN_SACK_PERMITTED && tcp_syn (th)) to->flags |= TCP_OPTS_FLAG_SACK_PERMITTED; break; case TCP_OPTION_SACK_BLOCK: /* If SACK permitted was not advertised or a SYN, break */ if ((to->flags & TCP_OPTS_FLAG_SACK_PERMITTED) == 0 || tcp_syn (th)) break; /* If too short or not correctly formatted, break */ if (opt_len < 10 || ((opt_len - 2) % TCP_OPTION_LEN_SACK_BLOCK)) break; to->flags |= TCP_OPTS_FLAG_SACK; to->n_sack_blocks = (opt_len - 2) / TCP_OPTION_LEN_SACK_BLOCK; vec_reset_length (to->sacks); for (j = 0; j < to->n_sack_blocks; j++) { b.start = clib_net_to_host_u32 (*(u32 *) (data + 2 + 4 * j)); b.end = clib_net_to_host_u32 (*(u32 *) (data + 6 + 4 * j)); vec_add1 (to->sacks, b); } break; default: /* Nothing to see here */ continue; } } } always_inline int tcp_segment_check_paws (tcp_connection_t * tc) { /* XXX normally test for timestamp should be lt instead of leq, but for * local testing this is not enough */ return tcp_opts_tstamp (&tc->opt) && tc->tsval_recent && timestamp_lt (tc->opt.tsval, tc->tsval_recent); } /** * Validate incoming segment as per RFC793 p. 69 and RFC1323 p. 19 * * It first verifies if segment has a wrapped sequence number (PAWS) and then * does the processing associated to the first four steps (ignoring security * and precedence): sequence number, rst bit and syn bit checks. * * @return 0 if segments passes validation. */ static int tcp_segment_validate (vlib_main_t * vm, tcp_connection_t * tc0, vlib_buffer_t * b0, tcp_header_t * th0, u32 * next0) { u8 paws_failed; if (PREDICT_FALSE (!tcp_ack (th0) && !tcp_rst (th0) && !tcp_syn (th0))) return -1; tcp_options_parse (th0, &tc0->opt); /* RFC1323: Check against wrapped sequence numbers (PAWS). If we have * timestamp to echo and it's less than tsval_recent, drop segment * but still send an ACK in order to retain TCP's mechanism for detecting * and recovering from half-open connections */ paws_failed = tcp_segment_check_paws (tc0); if (paws_failed) { clib_warning ("paws failed"); /* If it just so happens that a segment updates tsval_recent for a * segment over 24 days old, invalidate tsval_recent. */ if (timestamp_lt (tc0->tsval_recent_age + TCP_PAWS_IDLE, tcp_time_now ())) { /* Age isn't reset until we get a valid tsval (bsd inspired) */ tc0->tsval_recent = 0; } else { /* Drop after ack if not rst */ if (!tcp_rst (th0)) { tcp_make_ack (tc0, b0); *next0 = tcp_next_output (tc0->c_is_ip4); TCP_EVT_DBG (TCP_EVT_DUPACK_SENT, tc0); return -1; } } } /* 1st: check sequence number */ if (!tcp_segment_in_rcv_wnd (tc0, vnet_buffer (b0)->tcp.seq_number, vnet_buffer (b0)->tcp.seq_end)) { /* If our window is 0 and the packet is in sequence, let it pass * through for ack processing. It should be dropped later.*/ if (tc0->rcv_wnd == 0 && tc0->rcv_nxt == vnet_buffer (b0)->tcp.seq_number) { /* Make it look as if there's nothing to dequeue */ vnet_buffer (b0)->tcp.seq_end = vnet_buffer (b0)->tcp.seq_number; } else { /* If not RST, send dup ack */ if (!tcp_rst (th0)) { tcp_make_ack (tc0, b0); *next0 = tcp_next_output (tc0->c_is_ip4); TCP_EVT_DBG (TCP_EVT_DUPACK_SENT, tc0); } return -1; } } /* 2nd: check the RST bit */ if (tcp_rst (th0)) { tcp_connection_reset (tc0); return -1; } /* 3rd: check security and precedence (skip) */ /* 4th: check the SYN bit */ if (tcp_syn (th0)) { tcp_send_reset (b0, tc0->c_is_ip4); return -1; } /* If PAWS passed and segment in window, save timestamp */ if (!paws_failed) { tc0->tsval_recent = tc0->opt.tsval; tc0->tsval_recent_age = tcp_time_now (); } return 0; } always_inline int tcp_rcv_ack_is_acceptable (tcp_connection_t * tc0, vlib_buffer_t * tb0) { /* SND.UNA =< SEG.ACK =< SND.NXT */ return (seq_leq (tc0->snd_una, vnet_buffer (tb0)->tcp.ack_number) && seq_leq (vnet_buffer (tb0)->tcp.ack_number, tc0->snd_nxt)); } /** * Compute smoothed RTT as per VJ's '88 SIGCOMM and RFC6298 * * Note that although the original article, srtt and rttvar are scaled * to minimize round-off errors, here we don't. Instead, we rely on * better precision time measurements. * * TODO support us rtt resolution */ static void tcp_estimate_rtt (tcp_connection_t * tc, u32 mrtt) { int err; if (tc->srtt != 0) { err = mrtt - tc->srtt; tc->srtt += err >> 3; /* XXX Drop in RTT results in RTTVAR increase and bigger RTO. * The increase should be bound */ tc->rttvar += ((int) clib_abs (err) - (int) tc->rttvar) >> 2; } else { /* First measurement. */ tc->srtt = mrtt; tc->rttvar = mrtt >> 1; } } /** Update RTT estimate and RTO timer * * Measure RTT: We have two sources of RTT measurements: TSOPT and ACK * timing. Middle boxes are known to fiddle with TCP options so we * should give higher priority to ACK timing. * * return 1 if valid rtt 0 otherwise */ static int tcp_update_rtt (tcp_connection_t * tc, u32 ack) { u32 mrtt = 0; /* Karn's rule, part 1. Don't use retransmitted segments to estimate * RTT because they're ambiguous. */ if (tc->rtt_seq && seq_gt (ack, tc->rtt_seq) && !tc->rto_boff) { mrtt = tcp_time_now () - tc->rtt_ts; tc->rtt_seq = 0; } /* As per RFC7323 TSecr can be used for RTTM only if the segment advances * snd_una, i.e., the left side of the send window: * seq_lt (tc->snd_una, ack). Note: last condition could be dropped, we don't * try to update rtt for dupacks */ else if (tcp_opts_tstamp (&tc->opt) && tc->opt.tsecr && tc->bytes_acked) { mrtt = tcp_time_now () - tc->opt.tsecr; } /* Ignore dubious measurements */ if (mrtt == 0 || mrtt > TCP_RTT_MAX) return 0; tcp_estimate_rtt (tc, mrtt); tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX); return 1; } /** * Dequeue bytes that have been acked and while at it update RTT estimates. */ static void tcp_dequeue_acked (tcp_connection_t * tc, u32 ack) { /* Dequeue the newly ACKed bytes */ stream_session_dequeue_drop (&tc->connection, tc->bytes_acked); /* Update rtt and rto */ if (tcp_update_rtt (tc, ack)) { /* Good ACK received and valid RTT, make sure retransmit backoff is 0 */ tc->rto_boff = 0; } } /** * Check if dupack as per RFC5681 Sec. 2 * * This works only if called before updating snd_wnd. * */ always_inline u8 tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 new_snd_wnd) { return ((vnet_buffer (b)->tcp.ack_number == tc->snd_una) && seq_gt (tc->snd_una_max, tc->snd_una) && (vnet_buffer (b)->tcp.seq_end == vnet_buffer (b)->tcp.seq_number) && (new_snd_wnd == tc->snd_wnd)); } void scoreboard_remove_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole) { sack_scoreboard_hole_t *next, *prev; if (hole->next != TCP_INVALID_SACK_HOLE_INDEX) { next = pool_elt_at_index (sb->holes, hole->next); next->prev = hole->prev; } if (hole->prev != TCP_INVALID_SACK_HOLE_INDEX) { prev = pool_elt_at_index (sb->holes, hole->prev); prev->next = hole->next; } else { sb->head = hole->next; } pool_put (sb->holes, hole); } sack_scoreboard_hole_t * scoreboard_insert_hole (sack_scoreboard_t * sb, u32 prev_index, u32 start, u32 end) { sack_scoreboard_hole_t *hole, *next, *prev; u32 hole_index; pool_get (sb->holes, hole); memset (hole, 0, sizeof (*hole)); hole->start = start; hole->end = end; hole_index = hole - sb->holes; prev = scoreboard_get_hole (sb, prev_index); if (prev) { hole->prev = prev - sb->holes; hole->next = prev->next; if ((next = scoreboard_next_hole (sb, hole))) next->prev = hole_index; prev->next = hole_index; } else { sb->head = hole_index; hole->prev = TCP_INVALID_SACK_HOLE_INDEX; hole->next = TCP_INVALID_SACK_HOLE_INDEX; } return hole; } void tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) { sack_scoreboard_t *sb = &tc->sack_sb; sack_block_t *blk, tmp; sack_scoreboard_hole_t *hole, *next_hole, *last_hole, *new_hole; u32 blk_index = 0, old_sacked_bytes, hole_index; int i, j; sb->last_sacked_bytes = 0; sb->snd_una_adv = 0; old_sacked_bytes = sb->sacked_bytes; if (!tcp_opts_sack (&tc->opt) && sb->head == TCP_INVALID_SACK_HOLE_INDEX) return; /* Remove invalid blocks */ blk = tc->opt.sacks; while (blk < vec_end (tc->opt.sacks)) { if (seq_lt (blk->start, blk->end) && seq_gt (blk->start, tc->snd_una) && seq_gt (blk->start, ack) && seq_leq (blk->end, tc->snd_nxt)) { blk++; continue; } vec_del1 (tc->opt.sacks, blk - tc->opt.sacks); } /* Add block for cumulative ack */ if (seq_gt (ack, tc->snd_una)) { tmp.start = tc->snd_una; tmp.end = ack; vec_add1 (tc->opt.sacks, tmp); } if (vec_len (tc->opt.sacks) == 0) return; /* Make sure blocks are ordered */ for (i = 0; i < vec_len (tc->opt.sacks); i++) for (j = i + 1; j < vec_len (tc->opt.sacks); j++) if (seq_lt (tc->opt.sacks[j].start, tc->opt.sacks[i].start)) { tmp = tc->opt.sacks[i]; tc->opt.sacks[i] = tc->opt.sacks[j]; tc->opt.sacks[j] = tmp; } if (sb->head == TCP_INVALID_SACK_HOLE_INDEX) { /* If no holes, insert the first that covers all outstanding bytes */ last_hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX, tc->snd_una, tc->snd_una_max); sb->tail = scoreboard_hole_index (sb, last_hole); } else { /* If we have holes but snd_una_max is beyond the last hole, update * last hole end */ tmp = tc->opt.sacks[vec_len (tc->opt.sacks) - 1]; last_hole = scoreboard_last_hole (sb); if (seq_gt (tc->snd_una_max, sb->max_byte_sacked) && seq_gt (tc->snd_una_max, last_hole->end)) last_hole->end = tc->snd_una_max; } /* Walk the holes with the SACK blocks */ hole = pool_elt_at_index (sb->holes, sb->head); while (hole && blk_index < vec_len (tc->opt.sacks)) { blk = &tc->opt.sacks[blk_index]; if (seq_leq (blk->start, hole->start)) { /* Block covers hole. Remove hole */ if (seq_geq (blk->end, hole->end)) { next_hole = scoreboard_next_hole (sb, hole); /* Byte accounting */ if (seq_leq (hole->end, ack)) { /* Bytes lost because snd_wnd left edge advances */ if (next_hole && seq_leq (next_hole->start, ack)) sb->sacked_bytes -= next_hole->start - hole->end; else sb->sacked_bytes -= ack - hole->end; } else { sb->sacked_bytes += scoreboard_hole_bytes (hole); } /* snd_una needs to be advanced */ if (seq_geq (ack, hole->end)) { if (next_hole && seq_lt (ack, next_hole->start)) sb->snd_una_adv = next_hole->start - ack; else sb->snd_una_adv = sb->max_byte_sacked - ack; /* all these can be delivered */ sb->sacked_bytes -= sb->snd_una_adv; } /* About to remove last hole */ if (hole == last_hole) { sb->tail = hole->prev; last_hole = scoreboard_last_hole (sb); /* keep track of max byte sacked in case the last hole * is acked */ if (seq_gt (hole->end, sb->max_byte_sacked)) sb->max_byte_sacked = hole->end; } scoreboard_remove_hole (sb, hole); hole = next_hole; } /* Partial 'head' overlap */ else { if (seq_gt (blk->end, hole->start)) { sb->sacked_bytes += blk->end - hole->start; hole->start = blk->end; } blk_index++; } } else { /* Hole must be split */ if (seq_lt (blk->end, hole->end)) { sb->sacked_bytes += blk->end - blk->start; hole_index = scoreboard_hole_index (sb, hole); new_hole = scoreboard_insert_hole (sb, hole_index, blk->end, hole->end); /* Pool might've moved */ hole = scoreboard_get_hole (sb, hole_index); hole->end = blk->start; /* New or split of tail */ if ((last_hole->end == new_hole->end) || seq_lt (last_hole->end, new_hole->start)) { last_hole = new_hole; sb->tail = scoreboard_hole_index (sb, new_hole); } blk_index++; hole = scoreboard_next_hole (sb, hole); } else { sb->sacked_bytes += hole->end - blk->start; hole->end = blk->start; hole = scoreboard_next_hole (sb, hole); } } } sb->last_sacked_bytes = sb->sacked_bytes + sb->snd_una_adv - old_sacked_bytes; } /** Update snd_wnd * * If (SND.WL1 < SEG.SEQ or (SND.WL1 = SEG.SEQ and SND.WL2 =< SEG.ACK)), set * SND.WND <- SEG.WND, set SND.WL1 <- SEG.SEQ, and set SND.WL2 <- SEG.ACK */ static void tcp_update_snd_wnd (tcp_connection_t * tc, u32 seq, u32 ack, u32 snd_wnd) { if (seq_lt (tc->snd_wl1, seq) || (tc->snd_wl1 == seq && seq_leq (tc->snd_wl2, ack))) { tc->snd_wnd = snd_wnd; tc->snd_wl1 = seq; tc->snd_wl2 = ack; TCP_EVT_DBG (TCP_EVT_SND_WND, tc); } } void tcp_cc_congestion (tcp_connection_t * tc) { tc->snd_congestion = tc->snd_nxt; tc->cc_algo->congestion (tc); TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 4); } void tcp_cc_recover (tcp_connection_t * tc) { tc->cc_algo->recovered (tc); tc->rtx_bytes = 0; tc->rcv_dupacks = 0; tc->snd_nxt = tc->snd_una; tc->cc_algo->rcv_ack (tc); tc->tsecr_last_ack = tc->opt.tsecr; tcp_fastrecovery_1_smss_off (tc); tcp_fastrecovery_off (tc); TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3); } static void tcp_cc_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b) { u8 partial_ack; if (tcp_in_recovery (tc)) { partial_ack = seq_lt (tc->snd_una, tc->snd_congestion); if (!partial_ack) { /* Clear retransmitted bytes. */ tcp_cc_recover (tc); } else { TCP_EVT_DBG (TCP_EVT_CC_PACK, tc); /* Clear retransmitted bytes. XXX should we clear all? */ tc->rtx_bytes = 0; tc->cc_algo->rcv_cong_ack (tc, TCP_CC_PARTIALACK); /* In case snd_nxt is still in the past and output tries to * shove some new bytes */ tc->snd_nxt = tc->snd_una; /* XXX need proper RFC6675 support */ if (tc->sack_sb.last_sacked_bytes) { tcp_fast_retransmit (tc); } else { /* Retransmit first unacked segment */ tcp_retransmit_first_unacked (tc); /* If window allows, send 1 SMSS of new data */ if (seq_lt (tc->snd_nxt, tc->snd_congestion)) tc->snd_nxt = tc->snd_congestion; } } } else { tc->cc_algo->rcv_ack (tc); tc->tsecr_last_ack = tc->opt.tsecr; tc->rcv_dupacks = 0; } } static void tcp_cc_rcv_dupack (tcp_connection_t * tc, u32 ack) { // ASSERT (seq_geq(tc->snd_una, ack)); tc->rcv_dupacks++; if (tc->rcv_dupacks == TCP_DUPACK_THRESHOLD) { /* RFC6582 NewReno heuristic to avoid multiple fast retransmits */ if (tc->opt.tsecr != tc->tsecr_last_ack) { tc->rcv_dupacks = 0; return; } tcp_fastrecovery_on (tc); /* Handle congestion and dupack */ tcp_cc_congestion (tc); tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK); tcp_fast_retransmit (tc); /* Post retransmit update cwnd to ssthresh and account for the * three segments that have left the network and should've been * buffered at the receiver */ tc->cwnd = tc->ssthresh + TCP_DUPACK_THRESHOLD * tc->snd_mss; } else if (tc->rcv_dupacks > TCP_DUPACK_THRESHOLD) { ASSERT (tcp_in_fastrecovery (tc)); tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK); } } void tcp_cc_init (tcp_connection_t * tc) { tc->cc_algo = tcp_cc_algo_get (TCP_CC_NEWRENO); tc->cc_algo->init (tc); } static int tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b, tcp_header_t * th, u32 * next, u32 * error) { u32 new_snd_wnd; /* If the ACK acks something not yet sent (SEG.ACK > SND.NXT) */ if (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_nxt)) { /* If we have outstanding data and this is within the window, accept it, * probably retransmit has timed out. Otherwise ACK segment and then * drop it */ if (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_una_max)) { tcp_make_ack (tc, b); *next = tcp_next_output (tc->c_is_ip4); *error = TCP_ERROR_ACK_INVALID; TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 0, vnet_buffer (b)->tcp.ack_number); return -1; } tc->snd_nxt = vnet_buffer (b)->tcp.ack_number; *error = TCP_ERROR_ACK_FUTURE; TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 2, vnet_buffer (b)->tcp.ack_number); } /* If old ACK, probably it's an old dupack */ if (seq_lt (vnet_buffer (b)->tcp.ack_number, tc->snd_una)) { *error = TCP_ERROR_ACK_OLD; TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 1, vnet_buffer (b)->tcp.ack_number); if (tcp_in_fastrecovery (tc) && tc->rcv_dupacks == TCP_DUPACK_THRESHOLD) { TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc); tcp_cc_rcv_dupack (tc, vnet_buffer (b)->tcp.ack_number); } return -1; } if (tcp_opts_sack_permitted (&tc->opt)) tcp_rcv_sacks (tc, vnet_buffer (b)->tcp.ack_number); new_snd_wnd = clib_net_to_host_u16 (th->window) << tc->snd_wscale; if (tcp_ack_is_dupack (tc, b, new_snd_wnd)) { TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc, 1); tcp_cc_rcv_dupack (tc, vnet_buffer (b)->tcp.ack_number); *error = TCP_ERROR_ACK_DUP; return -1; } /* * Valid ACK */ tc->bytes_acked = vnet_buffer (b)->tcp.ack_number - tc->snd_una; tc->snd_una = vnet_buffer (b)->tcp.ack_number + tc->sack_sb.snd_una_adv; /* Dequeue ACKed data and update RTT */ tcp_dequeue_acked (tc, vnet_buffer (b)->tcp.ack_number); tcp_update_snd_wnd (tc, vnet_buffer (b)->tcp.seq_number, vnet_buffer (b)->tcp.ack_number, new_snd_wnd); /* If some of our sent bytes have been acked, update cc and retransmit * timer. */ if (tc->bytes_acked) { TCP_EVT_DBG (TCP_EVT_ACK_RCVD, tc, vnet_buffer (b)->tcp.ack_number); /* Updates congestion control (slow start/congestion avoidance) */ tcp_cc_rcv_ack (tc, b); /* If everything has been acked, stop retransmit timer * otherwise update */ if (tc->snd_una == tc->snd_una_max) tcp_retransmit_timer_reset (tc); else tcp_retransmit_timer_update (tc); } return 0; } /** * Build SACK list as per RFC2018. * * Makes sure the first block contains the segment that generated the current * ACK and the following ones are the ones most recently reported in SACK * blocks. * * @param tc TCP connection for which the SACK list is updated * @param start Start sequence number of the newest SACK block * @param end End sequence of the newest SACK block */ static void tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end) { sack_block_t *new_list = 0, block; int i; /* If the first segment is ooo add it to the list. Last write might've moved * rcv_nxt over the first segment. */ if (seq_lt (tc->rcv_nxt, start)) { block.start = start; block.end = end; vec_add1 (new_list, block); } /* Find the blocks still worth keeping. */ for (i = 0; i < vec_len (tc->snd_sacks); i++) { /* Discard if: * 1) rcv_nxt advanced beyond current block OR * 2) Segment overlapped by the first segment, i.e., it has been merged * into it.*/ if (seq_leq (tc->snd_sacks[i].start, tc->rcv_nxt) || seq_leq (tc->snd_sacks[i].start, end)) continue; /* Save to new SACK list. */ vec_add1 (new_list, tc->snd_sacks[i]); } ASSERT (vec_len (new_list) < TCP_MAX_SACK_BLOCKS); /* Replace old vector with new one */ vec_free (tc->snd_sacks); tc->snd_sacks = new_list; } /** Enqueue data for delivery to application */ always_inline int tcp_session_enqueue_data (tcp_connection_t * tc, vlib_buffer_t * b, u16 data_len) { int written; /* Pure ACK. Update rcv_nxt and be done. */ if (PREDICT_FALSE (data_len == 0)) { tc->rcv_nxt = vnet_buffer (b)->tcp.seq_end; return TCP_ERROR_PURE_ACK; } written = stream_session_enqueue_data (&tc->connection, vlib_buffer_get_current (b), data_len, 1 /* queue event */ ); TCP_EVT_DBG (TCP_EVT_INPUT, tc, 0, data_len, written); /* Update rcv_nxt */ if (PREDICT_TRUE (written == data_len)) { tc->rcv_nxt = vnet_buffer (b)->tcp.seq_end; } /* If more data written than expected, account for out-of-order bytes. */ else if (written > data_len) { tc->rcv_nxt = vnet_buffer (b)->tcp.seq_end + written - data_len; /* Send ACK confirming the update */ tc->flags |= TCP_CONN_SNDACK; } else if (written > 0) { /* We've written something but FIFO is probably full now */ tc->rcv_nxt += written; /* Depending on how fast the app is, all remaining buffers in burst will * not be enqueued. Should we inform peer of the damage? XXX */ return TCP_ERROR_PARTIALLY_ENQUEUED; } else { return TCP_ERROR_FIFO_FULL; } /* Update SACK list if need be */ if (tcp_opts_sack_permitted (&tc->opt)) { /* Remove SACK blocks that have been delivered */ tcp_update_sack_list (tc, tc->rcv_nxt, tc->rcv_nxt); } return TCP_ERROR_ENQUEUED; } /** Enqueue out-of-order data */ always_inline int tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b, u16 data_len) { stream_session_t *s0; u32 offset, seq; int rv; /* Pure ACK. Do nothing */ if (PREDICT_FALSE (data_len == 0)) { return TCP_ERROR_PURE_ACK; } s0 = stream_session_get (tc->c_s_index, tc->c_thread_index); seq = vnet_buffer (b)->tcp.seq_number; offset = seq - tc->rcv_nxt; rv = svm_fifo_enqueue_with_offset (s0->server_rx_fifo, s0->pid, offset, data_len, vlib_buffer_get_current (b)); /* Nothing written */ if (rv) { TCP_EVT_DBG (TCP_EVT_INPUT, tc, 1, data_len, 0); return TCP_ERROR_FIFO_FULL; } TCP_EVT_DBG (TCP_EVT_INPUT, tc, 1, data_len, data_len); /* Update SACK list if in use */ if (tcp_opts_sack_permitted (&tc->opt)) { ooo_segment_t *newest; u32 start, end; /* Get the newest segment from the fifo */ newest = svm_fifo_newest_ooo_segment (s0->server_rx_fifo); start = tc->rcv_nxt + ooo_segment_offset (s0->server_rx_fifo, newest); end = tc->rcv_nxt + ooo_segment_end_offset (s0->server_rx_fifo, newest); tcp_update_sack_list (tc, start, end); } return TCP_ERROR_ENQUEUED; } /** * Check if ACK could be delayed. If ack can be delayed, it should return * true for a full frame. If we're always acking return 0. */ always_inline int tcp_can_delack (tcp_connection_t * tc) { /* Send ack if ... */ if (TCP_ALWAYS_ACK /* just sent a rcv wnd 0 */ || (tc->flags & TCP_CONN_SENT_RCV_WND0) != 0 /* constrained to send ack */ || (tc->flags & TCP_CONN_SNDACK) != 0 /* we're almost out of tx wnd */ || tcp_available_snd_space (tc) < 2 * tc->snd_mss) return 0; return 1; } static int tcp_segment_rcv (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b, u16 n_data_bytes, u32 * next0) { u32 error = 0; /* Handle out-of-order data */ if (PREDICT_FALSE (vnet_buffer (b)->tcp.seq_number != tc->rcv_nxt)) { /* Old sequence numbers allowed through because they overlapped * the rx window */ if (seq_lt (vnet_buffer (b)->tcp.seq_number, tc->rcv_nxt)) { error = TCP_ERROR_SEGMENT_OLD; *next0 = TCP_NEXT_DROP; goto done; } error = tcp_session_enqueue_ooo (tc, b, n_data_bytes); /* N.B. Should not filter burst of dupacks. Two issues 1) dupacks open * cwnd on remote peer when congested 2) acks leaving should have the * latest rcv_wnd since the burst may eaten up all of it, so only the * old ones could be filtered. */ /* RFC2581: Send DUPACK for fast retransmit */ tcp_make_ack (tc, b); *next0 = tcp_next_output (tc->c_is_ip4); /* Mark as DUPACK. We may filter these in output if * the burst fills the holes. */ if (n_data_bytes) vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_DUPACK; TCP_EVT_DBG (TCP_EVT_DUPACK_SENT, tc); goto done; } /* In order data, enqueue. Fifo figures out by itself if any out-of-order * segments can be enqueued after fifo tail offset changes. */ error = tcp_session_enqueue_data (tc, b, n_data_bytes); if (n_data_bytes == 0) { *next0 = TCP_NEXT_DROP; goto done; } if (PREDICT_FALSE (error == TCP_ERROR_FIFO_FULL)) *next0 = TCP_NEXT_DROP; /* Check if ACK can be delayed */ if (!tcp_can_delack (tc)) { /* Nothing to do for pure ACKs XXX */ if (n_data_bytes == 0) goto done; *next0 = tcp_next_output (tc->c_is_ip4); tcp_make_ack (tc, b); } else { if (!tcp_timer_is_active (tc, TCP_TIMER_DELACK)) tcp_timer_set (tc, TCP_TIMER_DELACK, TCP_DELACK_TIME); } done: return error; } always_inline void tcp_established_inc_counter (vlib_main_t * vm, u8 is_ip4, u8 evt, u8 val) { if (PREDICT_TRUE (!val)) return; if (is_ip4) vlib_node_increment_counter (vm, tcp4_established_node.index, evt, val); else vlib_node_increment_counter (vm, tcp6_established_node.index, evt, val); } always_inline uword tcp46_established_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip4) { u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->cpu_index, errors = 0; tcp_main_t *tm = vnet_get_tcp_main (); from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; tcp_header_t *th0 = 0; tcp_connection_t *tc0; ip4_header_t *ip40; ip6_header_t *ip60; u32 n_advance_bytes0, n_data_bytes0; u32 next0 = TCP_ESTABLISHED_NEXT_DROP, error0 = TCP_ERROR_ENQUEUED; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index, my_thread_index); if (PREDICT_FALSE (tc0 == 0)) { error0 = TCP_ERROR_INVALID_CONNECTION; goto done; } /* Checksum computed by ipx_local no need to compute again */ if (is_ip4) { ip40 = vlib_buffer_get_current (b0); th0 = ip4_next_header (ip40); n_advance_bytes0 = (ip4_header_bytes (ip40) + tcp_header_bytes (th0)); n_data_bytes0 = clib_net_to_host_u16 (ip40->length) - n_advance_bytes0; } else { ip60 = vlib_buffer_get_current (b0); th0 = ip6_next_header (ip60); n_advance_bytes0 = tcp_header_bytes (th0); n_data_bytes0 = clib_net_to_host_u16 (ip60->payload_length) - n_advance_bytes0; n_advance_bytes0 += sizeof (ip60[0]); } /* SYNs, FINs and data consume sequence numbers */ vnet_buffer (b0)->tcp.seq_end = vnet_buffer (b0)->tcp.seq_number + tcp_is_syn (th0) + tcp_is_fin (th0) + n_data_bytes0; /* TODO header prediction fast path */ /* 1-4: check SEQ, RST, SYN */ if (PREDICT_FALSE (tcp_segment_validate (vm, tc0, b0, th0, &next0))) { error0 = TCP_ERROR_SEGMENT_INVALID; TCP_EVT_DBG (TCP_EVT_SEG_INVALID, tc0, vnet_buffer (b0)->tcp.seq_number, vnet_buffer (b0)->tcp.seq_end); goto done; } /* 5: check the ACK field */ if (tcp_rcv_ack (tc0, b0, th0, &next0, &error0)) { goto done; } /* 6: check the URG bit TODO */ /* 7: process the segment text */ vlib_buffer_advance (b0, n_advance_bytes0); error0 = tcp_segment_rcv (tm, tc0, b0, n_data_bytes0, &next0); /* 8: check the FIN bit */ if (tcp_fin (th0)) { /* Enter CLOSE-WAIT and notify session. Don't send ACK, instead * wait for session to call close. To avoid lingering * in CLOSE-WAIT, set timer (reuse WAITCLOSE). */ tc0->state = TCP_STATE_CLOSE_WAIT; TCP_EVT_DBG (TCP_EVT_FIN_RCVD, tc0); stream_session_disconnect_notify (&tc0->connection); tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_CLOSEWAIT_TIME); } done: b0->error = node->errors[error0]; if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } errors = session_manager_flush_enqueue_events (my_thread_index); tcp_established_inc_counter (vm, is_ip4, TCP_ERROR_EVENT_FIFO_FULL, errors); return from_frame->n_vectors; } static uword tcp4_established (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_established_inline (vm, node, from_frame, 1 /* is_ip4 */ ); } static uword tcp6_established (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_established_inline (vm, node, from_frame, 0 /* is_ip4 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_established_node) = { .function = tcp4_established, .name = "tcp4-established", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_ESTABLISHED_N_NEXT, .next_nodes = { #define _(s,n) [TCP_ESTABLISHED_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_established_node, tcp4_established); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_established_node) = { .function = tcp6_established, .name = "tcp6-established", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_ESTABLISHED_N_NEXT, .next_nodes = { #define _(s,n) [TCP_ESTABLISHED_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_established_node, tcp6_established); vlib_node_registration_t tcp4_syn_sent_node; vlib_node_registration_t tcp6_syn_sent_node; always_inline uword tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip4) { tcp_main_t *tm = vnet_get_tcp_main (); u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->cpu_index, errors = 0; u8 sst = is_ip4 ? SESSION_TYPE_IP4_TCP : SESSION_TYPE_IP6_TCP; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0, ack0, seq0; vlib_buffer_t *b0; tcp_header_t *tcp0 = 0; tcp_connection_t *tc0; ip4_header_t *ip40; ip6_header_t *ip60; u32 n_advance_bytes0, n_data_bytes0; tcp_connection_t *new_tc0; u32 next0 = TCP_SYN_SENT_NEXT_DROP, error0 = TCP_ERROR_ENQUEUED; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); tc0 = tcp_half_open_connection_get (vnet_buffer (b0)-> tcp.connection_index); ack0 = vnet_buffer (b0)->tcp.ack_number; seq0 = vnet_buffer (b0)->tcp.seq_number; /* Checksum computed by ipx_local no need to compute again */ if (is_ip4) { ip40 = vlib_buffer_get_current (b0); tcp0 = ip4_next_header (ip40); n_advance_bytes0 = (ip4_header_bytes (ip40) + tcp_header_bytes (tcp0)); n_data_bytes0 = clib_net_to_host_u16 (ip40->length) - n_advance_bytes0; } else { ip60 = vlib_buffer_get_current (b0); tcp0 = ip6_next_header (ip60); n_advance_bytes0 = tcp_header_bytes (tcp0); n_data_bytes0 = clib_net_to_host_u16 (ip60->payload_length) - n_advance_bytes0; n_advance_bytes0 += sizeof (ip60[0]); } if (PREDICT_FALSE (!tcp_ack (tcp0) && !tcp_rst (tcp0) && !tcp_syn (tcp0))) goto drop; /* SYNs, FINs and data consume sequence numbers */ vnet_buffer (b0)->tcp.seq_end = seq0 + tcp_is_syn (tcp0) + tcp_is_fin (tcp0) + n_data_bytes0; /* * 1. check the ACK bit */ /* * If the ACK bit is set * If SEG.ACK =< ISS, or SEG.ACK > SND.NXT, send a reset (unless * the RST bit is set, if so drop the segment and return) * <SEQ=SEG.ACK><CTL=RST> * and discard the segment. Return. * If SND.UNA =< SEG.ACK =< SND.NXT then the ACK is acceptable. */ if (tcp_ack (tcp0)) { if (ack0 <= tc0->iss || ack0 > tc0->snd_nxt) { if (!tcp_rst (tcp0)) tcp_send_reset (b0, is_ip4); goto drop; } /* Make sure ACK is valid */ if (tc0->snd_una > ack0) goto drop; } /* * 2. check the RST bit */ if (tcp_rst (tcp0)) { /* If ACK is acceptable, signal client that peer is not * willing to accept connection and drop connection*/ if (tcp_ack (tcp0)) { stream_session_connect_notify (&tc0->connection, sst, 1 /* fail */ ); tcp_connection_cleanup (tc0); } goto drop; } /* * 3. check the security and precedence (skipped) */ /* * 4. check the SYN bit */ /* No SYN flag. Drop. */ if (!tcp_syn (tcp0)) goto drop; /* Stop connection establishment and retransmit timers */ tcp_timer_reset (tc0, TCP_TIMER_ESTABLISH); tcp_timer_reset (tc0, TCP_TIMER_RETRANSMIT_SYN); /* Valid SYN or SYN-ACK. Move connection from half-open pool to * current thread pool. */ pool_get (tm->connections[my_thread_index], new_tc0); clib_memcpy (new_tc0, tc0, sizeof (*new_tc0)); new_tc0->c_thread_index = my_thread_index; /* Cleanup half-open connection XXX lock */ pool_put (tm->half_open_connections, tc0); new_tc0->rcv_nxt = vnet_buffer (b0)->tcp.seq_end; new_tc0->irs = seq0; /* Parse options */ tcp_options_parse (tcp0, &new_tc0->opt); if (tcp_opts_tstamp (&new_tc0->opt)) { new_tc0->tsval_recent = new_tc0->opt.tsval; new_tc0->tsval_recent_age = tcp_time_now (); } if (tcp_opts_wscale (&new_tc0->opt)) new_tc0->snd_wscale = new_tc0->opt.wscale; /* No scaling */ new_tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window); new_tc0->snd_wl1 = seq0; new_tc0->snd_wl2 = ack0; tcp_connection_init_vars (new_tc0); /* SYN-ACK: See if we can switch to ESTABLISHED state */ if (tcp_ack (tcp0)) { /* Our SYN is ACKed: we have iss < ack = snd_una */ /* TODO Dequeue acknowledged segments if we support Fast Open */ new_tc0->snd_una = ack0; new_tc0->state = TCP_STATE_ESTABLISHED; /* Make sure las is initialized for the wnd computation */ new_tc0->rcv_las = new_tc0->rcv_nxt; /* Notify app that we have connection */ stream_session_connect_notify (&new_tc0->connection, sst, 0); /* Make sure after data segment processing ACK is sent */ new_tc0->flags |= TCP_CONN_SNDACK; } /* SYN: Simultaneous open. Change state to SYN-RCVD and send SYN-ACK */ else { new_tc0->state = TCP_STATE_SYN_RCVD; /* Notify app that we have connection */ stream_session_connect_notify (&new_tc0->connection, sst, 0); tcp_make_synack (new_tc0, b0); next0 = tcp_next_output (is_ip4); goto drop; } /* Read data, if any */ if (n_data_bytes0) { error0 = tcp_segment_rcv (tm, new_tc0, b0, n_data_bytes0, &next0); if (error0 == TCP_ERROR_PURE_ACK) error0 = TCP_ERROR_SYN_ACKS_RCVD; } else { tcp_make_ack (new_tc0, b0); next0 = tcp_next_output (new_tc0->c_is_ip4); } drop: b0->error = error0 ? node->errors[error0] : 0; if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } errors = session_manager_flush_enqueue_events (my_thread_index); if (errors) { if (is_ip4) vlib_node_increment_counter (vm, tcp4_established_node.index, TCP_ERROR_EVENT_FIFO_FULL, errors); else vlib_node_increment_counter (vm, tcp6_established_node.index, TCP_ERROR_EVENT_FIFO_FULL, errors); } return from_frame->n_vectors; } static uword tcp4_syn_sent (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_syn_sent_inline (vm, node, from_frame, 1 /* is_ip4 */ ); } static uword tcp6_syn_sent_rcv (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_syn_sent_inline (vm, node, from_frame, 0 /* is_ip4 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_syn_sent_node) = { .function = tcp4_syn_sent, .name = "tcp4-syn-sent", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_SYN_SENT_N_NEXT, .next_nodes = { #define _(s,n) [TCP_SYN_SENT_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_syn_sent_node, tcp4_syn_sent); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_syn_sent_node) = { .function = tcp6_syn_sent_rcv, .name = "tcp6-syn-sent", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_SYN_SENT_N_NEXT, .next_nodes = { #define _(s,n) [TCP_SYN_SENT_NEXT_##s] = n, foreach_tcp_state_next #undef _ } ,}; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_syn_sent_node, tcp6_syn_sent_rcv); /** * Handles reception for all states except LISTEN, SYN-SENT and ESTABLISHED * as per RFC793 p. 64 */ always_inline uword tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip4) { tcp_main_t *tm = vnet_get_tcp_main (); u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->cpu_index, errors = 0; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; tcp_header_t *tcp0 = 0; tcp_connection_t *tc0; ip4_header_t *ip40; ip6_header_t *ip60; u32 n_advance_bytes0, n_data_bytes0; u32 next0 = TCP_RCV_PROCESS_NEXT_DROP, error0 = TCP_ERROR_ENQUEUED; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index, my_thread_index); if (PREDICT_FALSE (tc0 == 0)) { error0 = TCP_ERROR_INVALID_CONNECTION; goto drop; } /* Checksum computed by ipx_local no need to compute again */ if (is_ip4) { ip40 = vlib_buffer_get_current (b0); tcp0 = ip4_next_header (ip40); n_advance_bytes0 = (ip4_header_bytes (ip40) + tcp_header_bytes (tcp0)); n_data_bytes0 = clib_net_to_host_u16 (ip40->length) - n_advance_bytes0; } else { ip60 = vlib_buffer_get_current (b0); tcp0 = ip6_next_header (ip60); n_advance_bytes0 = tcp_header_bytes (tcp0); n_data_bytes0 = clib_net_to_host_u16 (ip60->payload_length) - n_advance_bytes0; n_advance_bytes0 += sizeof (ip60[0]); } /* SYNs, FINs and data consume sequence numbers */ vnet_buffer (b0)->tcp.seq_end = vnet_buffer (b0)->tcp.seq_number + tcp_is_syn (tcp0) + tcp_is_fin (tcp0) + n_data_bytes0; /* * Special treatment for CLOSED */ switch (tc0->state) { case TCP_STATE_CLOSED: goto drop; break; } /* * For all other states (except LISTEN) */ /* 1-4: check SEQ, RST, SYN */ if (PREDICT_FALSE (tcp_segment_validate (vm, tc0, b0, tcp0, &next0))) { error0 = TCP_ERROR_SEGMENT_INVALID; goto drop; } /* 5: check the ACK field */ switch (tc0->state) { case TCP_STATE_SYN_RCVD: /* * If the segment acknowledgment is not acceptable, form a * reset segment, * <SEQ=SEG.ACK><CTL=RST> * and send it. */ if (!tcp_rcv_ack_is_acceptable (tc0, b0)) { tcp_send_reset (b0, is_ip4); goto drop; } /* Switch state to ESTABLISHED */ tc0->state = TCP_STATE_ESTABLISHED; /* Initialize session variables */ tc0->snd_una = vnet_buffer (b0)->tcp.ack_number; tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window) << tc0->opt.wscale; tc0->snd_wl1 = vnet_buffer (b0)->tcp.seq_number; tc0->snd_wl2 = vnet_buffer (b0)->tcp.ack_number; /* Shoulder tap the server */ stream_session_accept_notify (&tc0->connection); /* Reset SYN-ACK retransmit timer */ tcp_retransmit_timer_reset (tc0); break; case TCP_STATE_ESTABLISHED: /* We can get packets in established state here because they * were enqueued before state change */ if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0)) goto drop; break; case TCP_STATE_FIN_WAIT_1: /* In addition to the processing for the ESTABLISHED state, if * our FIN is now acknowledged then enter FIN-WAIT-2 and * continue processing in that state. */ if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0)) goto drop; /* If FIN is ACKed */ if (tc0->snd_una == tc0->snd_una_max) { tc0->state = TCP_STATE_FIN_WAIT_2; /* Stop all timers, 2MSL will be set lower */ tcp_connection_timers_reset (tc0); } break; case TCP_STATE_FIN_WAIT_2: /* In addition to the processing for the ESTABLISHED state, if * the retransmission queue is empty, the user's CLOSE can be * acknowledged ("ok") but do not delete the TCB. */ if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0)) goto drop; /* check if rtx queue is empty and ack CLOSE TODO */ break; case TCP_STATE_CLOSE_WAIT: /* Do the same processing as for the ESTABLISHED state. */ if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0)) goto drop; break; case TCP_STATE_CLOSING: /* In addition to the processing for the ESTABLISHED state, if * the ACK acknowledges our FIN then enter the TIME-WAIT state, * otherwise ignore the segment. */ if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0)) goto drop; /* XXX test that send queue empty */ tc0->state = TCP_STATE_TIME_WAIT; goto drop; break; case TCP_STATE_LAST_ACK: /* The only thing that can arrive in this state is an * acknowledgment of our FIN. If our FIN is now acknowledged, * delete the TCB, enter the CLOSED state, and return. */ if (!tcp_rcv_ack_is_acceptable (tc0, b0)) goto drop; tc0->state = TCP_STATE_CLOSED; /* Don't delete the connection/session yet. Instead, wait a * reasonable amount of time until the pipes are cleared. In * particular, this makes sure that we won't have dead sessions * when processing events on the tx path */ tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_CLEANUP_TIME); /* Stop retransmit */ tcp_retransmit_timer_reset (tc0); goto drop; break; case TCP_STATE_TIME_WAIT: /* The only thing that can arrive in this state is a * retransmission of the remote FIN. Acknowledge it, and restart * the 2 MSL timeout. */ /* TODO */ goto drop; break; default: ASSERT (0); } /* 6: check the URG bit TODO */ /* 7: process the segment text */ switch (tc0->state) { case TCP_STATE_ESTABLISHED: case TCP_STATE_FIN_WAIT_1: case TCP_STATE_FIN_WAIT_2: error0 = tcp_segment_rcv (tm, tc0, b0, n_data_bytes0, &next0); break; case TCP_STATE_CLOSE_WAIT: case TCP_STATE_CLOSING: case TCP_STATE_LAST_ACK: case TCP_STATE_TIME_WAIT: /* This should not occur, since a FIN has been received from the * remote side. Ignore the segment text. */ break; } /* 8: check the FIN bit */ if (!tcp_fin (tcp0)) goto drop; switch (tc0->state) { case TCP_STATE_ESTABLISHED: case TCP_STATE_SYN_RCVD: /* Send FIN-ACK notify app and enter CLOSE-WAIT */ tcp_connection_timers_reset (tc0); tcp_make_fin (tc0, b0); next0 = tcp_next_output (tc0->c_is_ip4); stream_session_disconnect_notify (&tc0->connection); tc0->state = TCP_STATE_CLOSE_WAIT; break; case TCP_STATE_CLOSE_WAIT: case TCP_STATE_CLOSING: case TCP_STATE_LAST_ACK: /* move along .. */ break; case TCP_STATE_FIN_WAIT_1: tc0->state = TCP_STATE_TIME_WAIT; tcp_connection_timers_reset (tc0); tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME); break; case TCP_STATE_FIN_WAIT_2: /* Got FIN, send ACK! */ tc0->state = TCP_STATE_TIME_WAIT; tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_CLOSEWAIT_TIME); tcp_make_ack (tc0, b0); next0 = tcp_next_output (is_ip4); break; case TCP_STATE_TIME_WAIT: /* Remain in the TIME-WAIT state. Restart the 2 MSL time-wait * timeout. */ tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME); break; } TCP_EVT_DBG (TCP_EVT_FIN_RCVD, tc0); b0->error = error0 ? node->errors[error0] : 0; drop: if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } errors = session_manager_flush_enqueue_events (my_thread_index); if (errors) { if (is_ip4) vlib_node_increment_counter (vm, tcp4_established_node.index, TCP_ERROR_EVENT_FIFO_FULL, errors); else vlib_node_increment_counter (vm, tcp6_established_node.index, TCP_ERROR_EVENT_FIFO_FULL, errors); } return from_frame->n_vectors; } static uword tcp4_rcv_process (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_rcv_process_inline (vm, node, from_frame, 1 /* is_ip4 */ ); } static uword tcp6_rcv_process (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_rcv_process_inline (vm, node, from_frame, 0 /* is_ip4 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_rcv_process_node) = { .function = tcp4_rcv_process, .name = "tcp4-rcv-process", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_RCV_PROCESS_N_NEXT, .next_nodes = { #define _(s,n) [TCP_RCV_PROCESS_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_rcv_process_node, tcp4_rcv_process); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_rcv_process_node) = { .function = tcp6_rcv_process, .name = "tcp6-rcv-process", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_RCV_PROCESS_N_NEXT, .next_nodes = { #define _(s,n) [TCP_RCV_PROCESS_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_rcv_process_node, tcp6_rcv_process); vlib_node_registration_t tcp4_listen_node; vlib_node_registration_t tcp6_listen_node; /** * LISTEN state processing as per RFC 793 p. 65 */ always_inline uword tcp46_listen_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip4) { u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->cpu_index; tcp_main_t *tm = vnet_get_tcp_main (); u8 sst = is_ip4 ? SESSION_TYPE_IP4_TCP : SESSION_TYPE_IP6_TCP; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; tcp_header_t *th0 = 0; tcp_connection_t *lc0; ip4_header_t *ip40; ip6_header_t *ip60; tcp_connection_t *child0; u32 error0 = TCP_ERROR_SYNS_RCVD, next0 = TCP_LISTEN_NEXT_DROP; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); lc0 = tcp_listener_get (vnet_buffer (b0)->tcp.connection_index); if (is_ip4) { ip40 = vlib_buffer_get_current (b0); th0 = ip4_next_header (ip40); } else { ip60 = vlib_buffer_get_current (b0); th0 = ip6_next_header (ip60); } /* Create child session. For syn-flood protection use filter */ /* 1. first check for an RST */ if (tcp_rst (th0)) goto drop; /* 2. second check for an ACK */ if (tcp_ack (th0)) { tcp_send_reset (b0, is_ip4); goto drop; } /* 3. check for a SYN (did that already) */ /* Create child session and send SYN-ACK */ pool_get (tm->connections[my_thread_index], child0); memset (child0, 0, sizeof (*child0)); child0->c_c_index = child0 - tm->connections[my_thread_index]; child0->c_lcl_port = lc0->c_lcl_port; child0->c_rmt_port = th0->src_port; child0->c_is_ip4 = is_ip4; child0->c_thread_index = my_thread_index; if (is_ip4) { child0->c_lcl_ip4.as_u32 = ip40->dst_address.as_u32; child0->c_rmt_ip4.as_u32 = ip40->src_address.as_u32; } else { clib_memcpy (&child0->c_lcl_ip6, &ip60->dst_address, sizeof (ip6_address_t)); clib_memcpy (&child0->c_rmt_ip6, &ip60->src_address, sizeof (ip6_address_t)); } if (stream_session_accept (&child0->connection, lc0->c_s_index, sst, 0 /* notify */ )) { error0 = TCP_ERROR_CREATE_SESSION_FAIL; goto drop; } tcp_options_parse (th0, &child0->opt); child0->irs = vnet_buffer (b0)->tcp.seq_number; child0->rcv_nxt = vnet_buffer (b0)->tcp.seq_number + 1; child0->state = TCP_STATE_SYN_RCVD; /* RFC1323: TSval timestamps sent on {SYN} and {SYN,ACK} * segments are used to initialize PAWS. */ if (tcp_opts_tstamp (&child0->opt)) { child0->tsval_recent = child0->opt.tsval; child0->tsval_recent_age = tcp_time_now (); } if (tcp_opts_wscale (&child0->opt)) child0->snd_wscale = child0->opt.wscale; /* No scaling */ child0->snd_wnd = clib_net_to_host_u16 (th0->window); child0->snd_wl1 = vnet_buffer (b0)->tcp.seq_number; child0->snd_wl2 = vnet_buffer (b0)->tcp.ack_number; tcp_connection_init_vars (child0); TCP_EVT_DBG (TCP_EVT_SYN_RCVD, child0); /* Reuse buffer to make syn-ack and send */ tcp_make_synack (child0, b0); next0 = tcp_next_output (is_ip4); drop: if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { } b0->error = node->errors[error0]; vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } return from_frame->n_vectors; } static uword tcp4_listen (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_listen_inline (vm, node, from_frame, 1 /* is_ip4 */ ); } static uword tcp6_listen (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_listen_inline (vm, node, from_frame, 0 /* is_ip4 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_listen_node) = { .function = tcp4_listen, .name = "tcp4-listen", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_LISTEN_N_NEXT, .next_nodes = { #define _(s,n) [TCP_LISTEN_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_listen_node, tcp4_listen); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_listen_node) = { .function = tcp6_listen, .name = "tcp6-listen", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_LISTEN_N_NEXT, .next_nodes = { #define _(s,n) [TCP_LISTEN_NEXT_##s] = n, foreach_tcp_state_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_listen_node, tcp6_listen); vlib_node_registration_t tcp4_input_node; vlib_node_registration_t tcp6_input_node; typedef enum _tcp_input_next { TCP_INPUT_NEXT_DROP, TCP_INPUT_NEXT_LISTEN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_INPUT_NEXT_SYN_SENT, TCP_INPUT_NEXT_ESTABLISHED, TCP_INPUT_NEXT_RESET, TCP_INPUT_N_NEXT } tcp_input_next_t; #define foreach_tcp4_input_next \ _ (DROP, "error-drop") \ _ (LISTEN, "tcp4-listen") \ _ (RCV_PROCESS, "tcp4-rcv-process") \ _ (SYN_SENT, "tcp4-syn-sent") \ _ (ESTABLISHED, "tcp4-established") \ _ (RESET, "tcp4-reset") #define foreach_tcp6_input_next \ _ (DROP, "error-drop") \ _ (LISTEN, "tcp6-listen") \ _ (RCV_PROCESS, "tcp6-rcv-process") \ _ (SYN_SENT, "tcp6-syn-sent") \ _ (ESTABLISHED, "tcp6-established") \ _ (RESET, "tcp6-reset") typedef struct { u16 src_port; u16 dst_port; u8 state; } tcp_rx_trace_t; u8 * format_tcp_rx_trace (u8 * s, va_list * args) { CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *); CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *); tcp_rx_trace_t *t = va_arg (*args, tcp_rx_trace_t *); s = format (s, "TCP: src-port %d dst-port %U%s\n", clib_net_to_host_u16 (t->src_port), clib_net_to_host_u16 (t->dst_port), format_tcp_state, t->state); return s; } #define filter_flags (TCP_FLAG_SYN|TCP_FLAG_ACK|TCP_FLAG_RST|TCP_FLAG_FIN) always_inline uword tcp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip4) { u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->cpu_index; tcp_main_t *tm = vnet_get_tcp_main (); from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; tcp_header_t *tcp0 = 0; tcp_connection_t *tc0; ip4_header_t *ip40; ip6_header_t *ip60; u32 error0 = TCP_ERROR_NO_LISTENER, next0 = TCP_INPUT_NEXT_DROP; u8 flags0; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); vnet_buffer (b0)->tcp.flags = 0; if (is_ip4) { ip40 = vlib_buffer_get_current (b0); tcp0 = ip4_next_header (ip40); /* lookup session */ tc0 = (tcp_connection_t *) stream_session_lookup_transport4 (&ip40->dst_address, &ip40->src_address, tcp0->dst_port, tcp0->src_port, SESSION_TYPE_IP4_TCP, my_thread_index); } else { ip60 = vlib_buffer_get_current (b0); tcp0 = ip6_next_header (ip60); tc0 = (tcp_connection_t *) stream_session_lookup_transport6 (&ip60->src_address, &ip60->dst_address, tcp0->src_port, tcp0->dst_port, SESSION_TYPE_IP6_TCP, my_thread_index); } /* Session exists */ if (PREDICT_TRUE (0 != tc0)) { /* Save connection index */ vnet_buffer (b0)->tcp.connection_index = tc0->c_c_index; vnet_buffer (b0)->tcp.seq_number = clib_net_to_host_u32 (tcp0->seq_number); vnet_buffer (b0)->tcp.ack_number = clib_net_to_host_u32 (tcp0->ack_number); flags0 = tcp0->flags & filter_flags; next0 = tm->dispatch_table[tc0->state][flags0].next; error0 = tm->dispatch_table[tc0->state][flags0].error; if (PREDICT_FALSE (error0 == TCP_ERROR_DISPATCH)) { /* Overload tcp flags to store state */ vnet_buffer (b0)->tcp.flags = tc0->state; } } else { /* Send reset */ next0 = TCP_INPUT_NEXT_RESET; error0 = TCP_ERROR_NO_LISTENER; } b0->error = error0 ? node->errors[error0] : 0; if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } return from_frame->n_vectors; } static uword tcp4_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_input_inline (vm, node, from_frame, 1 /* is_ip4 */ ); } static uword tcp6_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_input_inline (vm, node, from_frame, 0 /* is_ip4 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_input_node) = { .function = tcp4_input, .name = "tcp4-input", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_INPUT_N_NEXT, .next_nodes = { #define _(s,n) [TCP_INPUT_NEXT_##s] = n, foreach_tcp4_input_next #undef _ }, .format_buffer = format_tcp_header, .format_trace = format_tcp_rx_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_input_node, tcp4_input); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_input_node) = { .function = tcp6_input, .name = "tcp6-input", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_INPUT_N_NEXT, .next_nodes = { #define _(s,n) [TCP_INPUT_NEXT_##s] = n, foreach_tcp6_input_next #undef _ }, .format_buffer = format_tcp_header, .format_trace = format_tcp_rx_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_input_node, tcp6_input); void tcp_update_time (f64 now, u32 thread_index) { tcp_main_t *tm = vnet_get_tcp_main (); tw_timer_expire_timers_16t_2w_512sl (&tm->timer_wheels[thread_index], now); } static void tcp_dispatch_table_init (tcp_main_t * tm) { int i, j; for (i = 0; i < ARRAY_LEN (tm->dispatch_table); i++) for (j = 0; j < ARRAY_LEN (tm->dispatch_table[i]); j++) { tm->dispatch_table[i][j].next = TCP_INPUT_NEXT_DROP; tm->dispatch_table[i][j].error = TCP_ERROR_DISPATCH; } #define _(t,f,n,e) \ do { \ tm->dispatch_table[TCP_STATE_##t][f].next = (n); \ tm->dispatch_table[TCP_STATE_##t][f].error = (e); \ } while (0) /* SYNs for new connections -> tcp-listen. */ _(LISTEN, TCP_FLAG_SYN, TCP_INPUT_NEXT_LISTEN, TCP_ERROR_NONE); /* ACK for for a SYN-ACK -> tcp-rcv-process. */ _(SYN_RCVD, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); /* SYN-ACK for a SYN */ _(SYN_SENT, TCP_FLAG_SYN | TCP_FLAG_ACK, TCP_INPUT_NEXT_SYN_SENT, TCP_ERROR_NONE); _(SYN_SENT, TCP_FLAG_ACK, TCP_INPUT_NEXT_SYN_SENT, TCP_ERROR_NONE); _(SYN_SENT, TCP_FLAG_RST, TCP_INPUT_NEXT_SYN_SENT, TCP_ERROR_NONE); _(SYN_SENT, TCP_FLAG_RST | TCP_FLAG_ACK, TCP_INPUT_NEXT_SYN_SENT, TCP_ERROR_NONE); /* ACK for for established connection -> tcp-established. */ _(ESTABLISHED, TCP_FLAG_ACK, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE); /* FIN for for established connection -> tcp-established. */ _(ESTABLISHED, TCP_FLAG_FIN, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE); _(ESTABLISHED, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE); _(ESTABLISHED, TCP_FLAG_RST, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE); /* ACK or FIN-ACK to our FIN */ _(FIN_WAIT_1, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); _(FIN_WAIT_1, TCP_FLAG_ACK | TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); /* FIN in reply to our FIN from the other side */ _(FIN_WAIT_1, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); /* FIN confirming that the peer (app) has closed */ _(FIN_WAIT_2, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); _(FIN_WAIT_2, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); _(LAST_ACK, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); #undef _ } clib_error_t * tcp_input_init (vlib_main_t * vm) { clib_error_t *error = 0; tcp_main_t *tm = vnet_get_tcp_main (); if ((error = vlib_call_init_function (vm, tcp_init))) return error; /* Initialize dispatch table. */ tcp_dispatch_table_init (tm); return error; } VLIB_INIT_FUNCTION (tcp_input_init); /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */