diff options
author | Sachin Saxena <sachin.saxena@freescale.com> | 2018-02-28 20:28:52 +0530 |
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committer | Sachin Saxena <sachin.saxena@nxp.com> | 2018-02-28 20:34:56 +0530 |
commit | 0689fce93ba269c48f83a2f70f971b3976d04c90 (patch) | |
tree | 4cc2908df3598507cc1828ac19d8c43b22450ffa /src/vnet/tcp/tcp_input.c | |
parent | 746b57564deede624261ab8a96c94f562f24d22c (diff) | |
parent | d594711a5d79859a7d0bde83a516f7ab52051d9b (diff) |
Merge branch 'stable/1710' of https://gerrit.fd.io/r/vpp into 17101710
Diffstat (limited to 'src/vnet/tcp/tcp_input.c')
-rw-r--r-- | src/vnet/tcp/tcp_input.c | 3215 |
1 files changed, 3215 insertions, 0 deletions
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c new file mode 100644 index 00000000..63d6fd87 --- /dev/null +++ b/src/vnet/tcp/tcp_input.c @@ -0,0 +1,3215 @@ +/* + * 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)); +} + +/** + * Parse TCP header options. + * + * @param th TCP header + * @param to TCP options data structure to be populated + * @return -1 if parsing failed + */ +int +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; + continue; + } + else + { + /* broken options */ + if (opts_len < 2) + return -1; + opt_len = data[1]; + + /* weird option length */ + if (opt_len < 2 || opt_len > opts_len) + return -1; + } + + /* 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 + 8 * j)); + b.end = clib_net_to_host_u32 (*(u32 *) (data + 6 + 8 * j)); + vec_add1 (to->sacks, b); + } + break; + default: + /* Nothing to see here */ + continue; + } + } + return 0; +} + +/** + * 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 + * + * Or at least that's what the theory says. It seems that this might not work + * very well with packet reordering and fast retransmit. XXX + */ +always_inline int +tcp_segment_check_paws (tcp_connection_t * tc) +{ + return tcp_opts_tstamp (&tc->rcv_opts) && tc->tsval_recent + && timestamp_lt (tc->rcv_opts.tsval, tc->tsval_recent); +} + +/** + * Update tsval recent + */ +always_inline void +tcp_update_timestamp (tcp_connection_t * tc, u32 seq, u32 seq_end) +{ + /* + * RFC1323: If Last.ACK.sent falls within the range of sequence numbers + * of an incoming segment: + * SEG.SEQ <= Last.ACK.sent < SEG.SEQ + SEG.LEN + * then the TSval from the segment is copied to TS.Recent; + * otherwise, the TSval is ignored. + */ + if (tcp_opts_tstamp (&tc->rcv_opts) && seq_leq (seq, tc->rcv_las) + && seq_leq (tc->rcv_las, seq_end)) + { + ASSERT (timestamp_leq (tc->tsval_recent, tc->rcv_opts.tsval)); + tc->tsval_recent = tc->rcv_opts.tsval; + tc->tsval_recent_age = tcp_time_now (); + } +} + +/** + * 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) +{ + if (PREDICT_FALSE (!tcp_ack (th0) && !tcp_rst (th0) && !tcp_syn (th0))) + return -1; + + if (PREDICT_FALSE (tcp_options_parse (th0, &tc0->rcv_opts))) + { + clib_warning ("options parse error"); + return -1; + } + + if (tcp_segment_check_paws (tc0)) + { + if (CLIB_DEBUG > 2) + { + clib_warning ("paws failed\n%U", format_tcp_connection, tc0, 2); + clib_warning ("seq %u seq_end %u ack %u", + vnet_buffer (b0)->tcp.seq_number - tc0->irs, + vnet_buffer (b0)->tcp.seq_end - tc0->irs, + vnet_buffer (b0)->tcp.ack_number - tc0->iss); + } + TCP_EVT_DBG (TCP_EVT_PAWS_FAIL, tc0, vnet_buffer (b0)->tcp.seq_number, + vnet_buffer (b0)->tcp.seq_end); + + /* 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; + clib_warning ("paws failed - really old segment. REALLY?"); + } + 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) + { + /* TODO Should segment be tagged? */ + } + 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)) + { + /* TODO implement RFC 5961 */ + if (tc0->state == TCP_STATE_SYN_RCVD) + { + tcp_make_synack (tc0, b0); + TCP_EVT_DBG (TCP_EVT_SYN_RCVD, tc0, 0); + } + else + { + tcp_make_ack (tc0, b0); + TCP_EVT_DBG (TCP_EVT_SYNACK_RCVD, tc0); + } + *next0 = tcp_next_output (tc0->c_is_ip4); + return -1; + } + + /* If segment in window, save timestamp */ + tcp_update_timestamp (tc0, vnet_buffer (b0)->tcp.seq_number, + vnet_buffer (b0)->tcp.seq_end); + 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, diff; + + if (tc->srtt != 0) + { + err = mrtt - tc->srtt; + + /* XXX Drop in RTT results in RTTVAR increase and bigger RTO. + * The increase should be bound */ + tc->srtt = clib_max ((int) tc->srtt + (err >> 3), 1); + diff = (clib_abs (err) - (int) tc->rttvar) >> 2; + tc->rttvar = clib_max ((int) tc->rttvar + diff, 1); + } + else + { + /* First measurement. */ + tc->srtt = mrtt; + tc->rttvar = mrtt >> 1; + } +} + +void +tcp_update_rto (tcp_connection_t * tc) +{ + tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX); + tc->rto = clib_max (tc->rto, TCP_RTO_MIN); +} + +/** + * 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. + * + * This should be called only if previously sent bytes have been acked. + * + * 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 (tcp_in_cong_recovery (tc) || tc->sack_sb.sacked_bytes) + goto done; + + if (tc->rtt_ts && seq_geq (ack, tc->rtt_seq)) + { + mrtt = tcp_time_now () - tc->rtt_ts; + } + /* 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). This is a condition for calling update_rtt */ + else if (tcp_opts_tstamp (&tc->rcv_opts) && tc->rcv_opts.tsecr) + { + mrtt = tcp_time_now () - tc->rcv_opts.tsecr; + } + + /* Ignore dubious measurements */ + if (mrtt == 0 || mrtt > TCP_RTT_MAX) + goto done; + + tcp_estimate_rtt (tc, mrtt); + +done: + + /* Allow measuring of a new RTT */ + tc->rtt_ts = 0; + + /* If we got here something must've been ACKed so make sure boff is 0, + * even if mrrt is not valid since we update the rto lower */ + tc->rto_boff = 0; + tcp_update_rto (tc); + + return 0; +} + +/** + * 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 add SACKed bytes */ + stream_session_dequeue_drop (&tc->connection, + tc->bytes_acked + tc->sack_sb.snd_una_adv); + + tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una); + + /* Update rtt and rto */ + tcp_update_rtt (tc, ack); + + /* If everything has been acked, stop retransmit timer + * otherwise update. */ + tcp_retransmit_timer_update (tc); +} + +/** + * Check if duplicate ack as per RFC5681 Sec. 2 + */ +static u8 +tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 prev_snd_wnd, + u32 prev_snd_una) +{ + return ((vnet_buffer (b)->tcp.ack_number == prev_snd_una) + && seq_gt (tc->snd_una_max, tc->snd_una) + && (vnet_buffer (b)->tcp.seq_end == vnet_buffer (b)->tcp.seq_number) + && (prev_snd_wnd == tc->snd_wnd)); +} + +/** + * Checks if ack is a congestion control event. + */ +static u8 +tcp_ack_is_cc_event (tcp_connection_t * tc, vlib_buffer_t * b, + u32 prev_snd_wnd, u32 prev_snd_una, u8 * is_dack) +{ + /* Check if ack is duplicate. Per RFC 6675, ACKs that SACK new data are + * defined to be 'duplicate' */ + *is_dack = tc->sack_sb.last_sacked_bytes + || tcp_ack_is_dupack (tc, b, prev_snd_wnd, prev_snd_una); + + return ((*is_dack || tcp_in_cong_recovery (tc)) && !tcp_is_lost_fin (tc)); +} + +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; + } + else + { + sb->tail = 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; + } + + if (scoreboard_hole_index (sb, hole) == sb->cur_rxt_hole) + sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX; + + /* Poison the entry */ + if (CLIB_DEBUG > 0) + memset (hole, 0xfe, sizeof (*hole)); + + 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 = scoreboard_hole_index (sb, hole); + + prev = scoreboard_get_hole (sb, prev_index); + if (prev) + { + hole->prev = prev_index; + hole->next = prev->next; + + if ((next = scoreboard_next_hole (sb, hole))) + next->prev = hole_index; + else + sb->tail = 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 +scoreboard_update_bytes (tcp_connection_t * tc, sack_scoreboard_t * sb) +{ + sack_scoreboard_hole_t *hole, *prev; + u32 bytes = 0, blks = 0; + + sb->lost_bytes = 0; + sb->sacked_bytes = 0; + hole = scoreboard_last_hole (sb); + if (!hole) + return; + + if (seq_gt (sb->high_sacked, hole->end)) + { + bytes = sb->high_sacked - hole->end; + blks = 1; + } + + while ((prev = scoreboard_prev_hole (sb, hole)) + && (bytes < (TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss + && blks < TCP_DUPACK_THRESHOLD)) + { + bytes += hole->start - prev->end; + blks++; + hole = prev; + } + + while (hole) + { + sb->lost_bytes += scoreboard_hole_bytes (hole); + hole->is_lost = 1; + prev = hole; + hole = scoreboard_prev_hole (sb, hole); + if (hole) + bytes += prev->start - hole->end; + } + sb->sacked_bytes = bytes; +} + +/** + * Figure out the next hole to retransmit + * + * Follows logic proposed in RFC6675 Sec. 4, NextSeg() + */ +sack_scoreboard_hole_t * +scoreboard_next_rxt_hole (sack_scoreboard_t * sb, + sack_scoreboard_hole_t * start, + u8 have_sent_1_smss, + u8 * can_rescue, u8 * snd_limited) +{ + sack_scoreboard_hole_t *hole = 0; + + hole = start ? start : scoreboard_first_hole (sb); + while (hole && seq_leq (hole->end, sb->high_rxt) && hole->is_lost) + hole = scoreboard_next_hole (sb, hole); + + /* Nothing, return */ + if (!hole) + { + sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX; + return 0; + } + + /* Rule (1): if higher than rxt, less than high_sacked and lost */ + if (hole->is_lost && seq_lt (hole->start, sb->high_sacked)) + { + sb->cur_rxt_hole = scoreboard_hole_index (sb, hole); + } + else + { + /* Rule (2): output takes care of transmitting new data */ + if (!have_sent_1_smss) + { + hole = 0; + sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX; + } + /* Rule (3): if hole not lost */ + else if (seq_lt (hole->start, sb->high_sacked)) + { + *snd_limited = 1; + sb->cur_rxt_hole = scoreboard_hole_index (sb, hole); + } + /* Rule (4): if hole beyond high_sacked */ + else + { + ASSERT (seq_geq (hole->start, sb->high_sacked)); + *snd_limited = 1; + *can_rescue = 1; + /* HighRxt MUST NOT be updated */ + return 0; + } + } + + if (hole && seq_lt (sb->high_rxt, hole->start)) + sb->high_rxt = hole->start; + + return hole; +} + +void +scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 seq) +{ + sack_scoreboard_hole_t *hole; + hole = scoreboard_first_hole (sb); + if (hole) + { + seq = seq_gt (seq, hole->start) ? seq : hole->start; + sb->cur_rxt_hole = sb->head; + } + sb->high_rxt = seq; +} + +/** + * Test that scoreboard is sane after recovery + * + * Returns 1 if scoreboard is empty or if first hole beyond + * snd_una. + */ +u8 +tcp_scoreboard_is_sane_post_recovery (tcp_connection_t * tc) +{ + sack_scoreboard_hole_t *hole; + hole = scoreboard_first_hole (&tc->sack_sb); + return (!hole || seq_geq (hole->start, tc->snd_una)); +} + +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; + 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; + sb->last_bytes_delivered = 0; + + if (!tcp_opts_sack (&tc->rcv_opts) + && sb->head == TCP_INVALID_SACK_HOLE_INDEX) + return; + + /* Remove invalid blocks */ + blk = tc->rcv_opts.sacks; + while (blk < vec_end (tc->rcv_opts.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_una_max)) + { + blk++; + continue; + } + vec_del1 (tc->rcv_opts.sacks, blk - tc->rcv_opts.sacks); + } + + /* Add block for cumulative ack */ + if (seq_gt (ack, tc->snd_una)) + { + tmp.start = tc->snd_una; + tmp.end = ack; + vec_add1 (tc->rcv_opts.sacks, tmp); + } + + if (vec_len (tc->rcv_opts.sacks) == 0) + return; + + tcp_scoreboard_trace_add (tc, ack); + + /* Make sure blocks are ordered */ + for (i = 0; i < vec_len (tc->rcv_opts.sacks); i++) + for (j = i + 1; j < vec_len (tc->rcv_opts.sacks); j++) + if (seq_lt (tc->rcv_opts.sacks[j].start, tc->rcv_opts.sacks[i].start)) + { + tmp = tc->rcv_opts.sacks[i]; + tc->rcv_opts.sacks[i] = tc->rcv_opts.sacks[j]; + tc->rcv_opts.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); + tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1]; + sb->high_sacked = tmp.end; + } + else + { + /* If we have holes but snd_una_max is beyond the last hole, update + * last hole end */ + tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1]; + last_hole = scoreboard_last_hole (sb); + if (seq_gt (tc->snd_una_max, last_hole->end)) + { + if (seq_geq (last_hole->start, sb->high_sacked)) + { + last_hole->end = tc->snd_una_max; + } + /* New hole after high sacked block */ + else if (seq_lt (sb->high_sacked, tc->snd_una_max)) + { + scoreboard_insert_hole (sb, sb->tail, sb->high_sacked, + tc->snd_una_max); + } + } + /* Keep track of max byte sacked for when the last hole + * is acked */ + if (seq_gt (tmp.end, sb->high_sacked)) + sb->high_sacked = tmp.end; + } + + /* Walk the holes with the SACK blocks */ + hole = pool_elt_at_index (sb->holes, sb->head); + while (hole && blk_index < vec_len (tc->rcv_opts.sacks)) + { + blk = &tc->rcv_opts.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: snd_una needs to be advanced */ + if (blk->end == ack) + { + if (next_hole) + { + if (seq_lt (ack, next_hole->start)) + sb->snd_una_adv = next_hole->start - ack; + sb->last_bytes_delivered += + next_hole->start - hole->end; + } + else + { + ASSERT (seq_geq (sb->high_sacked, ack)); + sb->snd_una_adv = sb->high_sacked - ack; + sb->last_bytes_delivered += sb->high_sacked - hole->end; + } + } + + scoreboard_remove_hole (sb, hole); + hole = next_hole; + } + /* Partial 'head' overlap */ + else + { + if (seq_gt (blk->end, hole->start)) + { + hole->start = blk->end; + } + blk_index++; + } + } + else + { + /* Hole must be split */ + if (seq_lt (blk->end, hole->end)) + { + hole_index = scoreboard_hole_index (sb, hole); + next_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; + blk_index++; + ASSERT (hole->next == scoreboard_hole_index (sb, next_hole)); + } + else if (seq_lt (blk->start, hole->end)) + { + hole->end = blk->start; + } + hole = scoreboard_next_hole (sb, hole); + } + } + + scoreboard_update_bytes (tc, sb); + sb->last_sacked_bytes = sb->sacked_bytes + - (old_sacked_bytes - sb->last_bytes_delivered); + ASSERT (sb->last_sacked_bytes <= sb->sacked_bytes); + ASSERT (sb->sacked_bytes == 0 + || sb->sacked_bytes < tc->snd_una_max - seq_max (tc->snd_una, ack)); + ASSERT (sb->last_sacked_bytes + sb->lost_bytes <= tc->snd_una_max + - seq_max (tc->snd_una, ack)); + ASSERT (sb->head == TCP_INVALID_SACK_HOLE_INDEX || tcp_in_recovery (tc) + || sb->holes[sb->head].start == ack + sb->snd_una_adv); +} + +/** + * Try to update snd_wnd based on feedback received from peer. + * + * If successful, and new window is 'effectively' 0, activate persist + * timer. + */ +static void +tcp_update_snd_wnd (tcp_connection_t * tc, u32 seq, u32 ack, u32 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 */ + 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); + + if (tc->snd_wnd < tc->snd_mss) + { + /* Set persist timer if not set and we just got 0 wnd */ + if (!tcp_timer_is_active (tc, TCP_TIMER_PERSIST) + && !tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)) + tcp_persist_timer_set (tc); + } + else + { + tcp_persist_timer_reset (tc); + if (!tcp_in_recovery (tc) && tc->rto_boff > 0) + { + tc->rto_boff = 0; + tcp_update_rto (tc); + } + } + } +} + +void +tcp_cc_init_congestion (tcp_connection_t * tc) +{ + tcp_fastrecovery_on (tc); + tc->snd_congestion = tc->snd_una_max; + tc->cc_algo->congestion (tc); + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 4); +} + +static void +tcp_cc_recovery_exit (tcp_connection_t * tc) +{ + /* Deflate rto */ + tc->rto_boff = 0; + tcp_update_rto (tc); + tc->snd_rxt_ts = 0; + tc->snd_nxt = tc->snd_una_max; + tcp_recovery_off (tc); + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3); +} + +void +tcp_cc_fastrecovery_exit (tcp_connection_t * tc) +{ + tc->cc_algo->recovered (tc); + tc->snd_rxt_bytes = 0; + tc->rcv_dupacks = 0; + tc->snd_nxt = tc->snd_una_max; + tcp_fastrecovery_off (tc); + tcp_fastrecovery_1_smss_off (tc); + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3); +} + +static void +tcp_cc_congestion_undo (tcp_connection_t * tc) +{ + tc->cwnd = tc->prev_cwnd; + tc->ssthresh = tc->prev_ssthresh; + tc->snd_nxt = tc->snd_una_max; + tc->rcv_dupacks = 0; + if (tcp_in_recovery (tc)) + tcp_cc_recovery_exit (tc); + ASSERT (tc->rto_boff == 0); + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 5); + /* TODO extend for fastrecovery */ +} + +static u8 +tcp_cc_is_spurious_retransmit (tcp_connection_t * tc) +{ + return (tcp_in_recovery (tc) && tc->rto_boff == 1 + && tc->snd_rxt_ts + && tcp_opts_tstamp (&tc->rcv_opts) + && timestamp_lt (tc->rcv_opts.tsecr, tc->snd_rxt_ts)); +} + +int +tcp_cc_recover (tcp_connection_t * tc) +{ + ASSERT (tcp_in_cong_recovery (tc)); + if (tcp_cc_is_spurious_retransmit (tc)) + { + tcp_cc_congestion_undo (tc); + return 1; + } + + if (tcp_in_recovery (tc)) + tcp_cc_recovery_exit (tc); + else if (tcp_in_fastrecovery (tc)) + tcp_cc_fastrecovery_exit (tc); + + ASSERT (tc->rto_boff == 0); + ASSERT (!tcp_in_cong_recovery (tc)); + ASSERT (tcp_scoreboard_is_sane_post_recovery (tc)); + return 0; +} + +static void +tcp_cc_update (tcp_connection_t * tc, vlib_buffer_t * b) +{ + ASSERT (!tcp_in_cong_recovery (tc) || tcp_is_lost_fin (tc)); + + /* Congestion avoidance */ + tc->cc_algo->rcv_ack (tc); + tc->tsecr_last_ack = tc->rcv_opts.tsecr; + + /* If a cumulative ack, make sure dupacks is 0 */ + tc->rcv_dupacks = 0; + + /* When dupacks hits the threshold we only enter fast retransmit if + * cumulative ack covers more than snd_congestion. Should snd_una + * wrap this test may fail under otherwise valid circumstances. + * Therefore, proactively update snd_congestion when wrap detected. */ + if (PREDICT_FALSE + (seq_leq (tc->snd_congestion, tc->snd_una - tc->bytes_acked) + && seq_gt (tc->snd_congestion, tc->snd_una))) + tc->snd_congestion = tc->snd_una - 1; +} + +static u8 +tcp_should_fastrecover_sack (tcp_connection_t * tc) +{ + return (TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss < tc->sack_sb.sacked_bytes; +} + +static u8 +tcp_should_fastrecover (tcp_connection_t * tc) +{ + return (tc->rcv_dupacks == TCP_DUPACK_THRESHOLD + || tcp_should_fastrecover_sack (tc)); +} + +/** + * One function to rule them all ... and in the darkness bind them + */ +static void +tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack) +{ + u32 rxt_delivered; + + /* + * Duplicate ACK. Check if we should enter fast recovery, or if already in + * it account for the bytes that left the network. + */ + if (is_dack) + { + ASSERT (tc->snd_una != tc->snd_una_max + || tc->sack_sb.last_sacked_bytes); + + tc->rcv_dupacks++; + + if (tc->rcv_dupacks > TCP_DUPACK_THRESHOLD && !tc->bytes_acked) + { + ASSERT (tcp_in_fastrecovery (tc)); + /* Pure duplicate ack. If some data got acked, it's handled lower */ + tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK); + return; + } + else if (tcp_should_fastrecover (tc)) + { + /* Things are already bad */ + if (tcp_in_cong_recovery (tc)) + { + tc->rcv_dupacks = 0; + goto partial_ack_test; + } + + /* If of of the two conditions lower hold, reset dupacks because + * we're probably after timeout (RFC6582 heuristics). + * If Cumulative ack does not cover more than congestion threshold, + * and: + * 1) The following doesn't hold: The congestion window is greater + * than SMSS bytes and the difference between highest_ack + * and prev_highest_ack is at most 4*SMSS bytes + * 2) Echoed timestamp in the last non-dup ack does not equal the + * stored timestamp + */ + if (seq_leq (tc->snd_una, tc->snd_congestion) + && ((!(tc->cwnd > tc->snd_mss + && tc->bytes_acked <= 4 * tc->snd_mss)) + || (tc->rcv_opts.tsecr != tc->tsecr_last_ack))) + { + tc->rcv_dupacks = 0; + return; + } + + tcp_cc_init_congestion (tc); + tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK); + + /* The first segment MUST be retransmitted */ + tcp_retransmit_first_unacked (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 XXX */ + tc->cwnd = tc->ssthresh + tc->rcv_dupacks * tc->snd_mss; + ASSERT (tc->cwnd >= tc->snd_mss); + + /* If cwnd allows, send more data */ + if (tcp_opts_sack_permitted (&tc->rcv_opts)) + { + scoreboard_init_high_rxt (&tc->sack_sb, + tc->snd_una + tc->snd_mss); + tcp_fast_retransmit_sack (tc); + } + else + { + tcp_fast_retransmit_no_sack (tc); + } + + return; + } + else if (!tc->bytes_acked + || (tc->bytes_acked && !tcp_in_cong_recovery (tc))) + { + tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK); + return; + } + else + goto partial_ack; + } + +partial_ack_test: + + if (!tc->bytes_acked) + return; + +partial_ack: + /* + * Legitimate ACK. 1) See if we can exit recovery + */ + /* XXX limit this only to first partial ack? */ + tcp_retransmit_timer_update (tc); + + if (seq_geq (tc->snd_una, tc->snd_congestion)) + { + /* If spurious return, we've already updated everything */ + if (tcp_cc_recover (tc)) + { + tc->tsecr_last_ack = tc->rcv_opts.tsecr; + return; + } + + tc->snd_nxt = tc->snd_una_max; + + /* Treat as congestion avoidance ack */ + tc->cc_algo->rcv_ack (tc); + tc->tsecr_last_ack = tc->rcv_opts.tsecr; + return; + } + + /* + * Legitimate ACK. 2) If PARTIAL ACK try to retransmit + */ + TCP_EVT_DBG (TCP_EVT_CC_PACK, tc); + + /* RFC6675: If the incoming ACK is a cumulative acknowledgment, + * reset dupacks to 0 */ + tc->rcv_dupacks = 0; + + tcp_retransmit_first_unacked (tc); + + /* Post RTO timeout don't try anything fancy */ + if (tcp_in_recovery (tc)) + return; + + /* Remove retransmitted bytes that have been delivered */ + ASSERT (tc->bytes_acked + tc->sack_sb.snd_una_adv + >= tc->sack_sb.last_bytes_delivered + || (tc->flags & TCP_CONN_FINSNT)); + + if (seq_lt (tc->snd_una, tc->sack_sb.high_rxt)) + { + /* If we have sacks and we haven't gotten an ack beyond high_rxt, + * remove sacked bytes delivered */ + rxt_delivered = tc->bytes_acked + tc->sack_sb.snd_una_adv + - tc->sack_sb.last_bytes_delivered; + ASSERT (tc->snd_rxt_bytes >= rxt_delivered); + tc->snd_rxt_bytes -= rxt_delivered; + } + else + { + /* Either all retransmitted holes have been acked, or we're + * "in the blind" and retransmitting segment by segment */ + tc->snd_rxt_bytes = 0; + } + + tc->cc_algo->rcv_cong_ack (tc, TCP_CC_PARTIALACK); + + /* + * Since this was a partial ack, try to retransmit some more data + */ + tcp_fast_retransmit (tc); +} + +void +tcp_cc_init (tcp_connection_t * tc) +{ + tc->cc_algo = tcp_cc_algo_get (TCP_CC_NEWRENO); + tc->cc_algo->init (tc); +} + +/** + * Process incoming ACK + */ +static int +tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b, + tcp_header_t * th, u32 * next, u32 * error) +{ + u32 prev_snd_wnd, prev_snd_una; + u8 is_dack; + + TCP_EVT_DBG (TCP_EVT_CC_STAT, tc); + + /* If the ACK acks something not yet sent (SEG.ACK > SND.NXT) */ + if (PREDICT_FALSE (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; + } + + TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 2, + vnet_buffer (b)->tcp.ack_number); + + tc->snd_nxt = vnet_buffer (b)->tcp.ack_number; + *error = TCP_ERROR_ACK_FUTURE; + } + + /* If old ACK, probably it's an old dupack */ + if (PREDICT_FALSE (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_handle_event (tc, 1); + } + /* Don't drop yet */ + return 0; + } + + /* + * Looks okay, process feedback + */ + + if (tcp_opts_sack_permitted (&tc->rcv_opts)) + tcp_rcv_sacks (tc, vnet_buffer (b)->tcp.ack_number); + + prev_snd_wnd = tc->snd_wnd; + prev_snd_una = tc->snd_una; + tcp_update_snd_wnd (tc, vnet_buffer (b)->tcp.seq_number, + vnet_buffer (b)->tcp.ack_number, + clib_net_to_host_u16 (th->window) << tc->snd_wscale); + 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; + tcp_validate_txf_size (tc, tc->bytes_acked); + + if (tc->bytes_acked) + tcp_dequeue_acked (tc, vnet_buffer (b)->tcp.ack_number); + + TCP_EVT_DBG (TCP_EVT_ACK_RCVD, tc); + + /* + * Check if we have congestion event + */ + + if (tcp_ack_is_cc_event (tc, b, prev_snd_wnd, prev_snd_una, &is_dack)) + { + tcp_cc_handle_event (tc, is_dack); + if (!tcp_in_cong_recovery (tc)) + return 0; + *error = TCP_ERROR_ACK_DUP; + TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc, 1); + return vnet_buffer (b)->tcp.data_len ? 0 : -1; + } + + /* + * Update congestion control (slow start/congestion avoidance) + */ + tcp_cc_update (tc, b); + + return 0; +} + +static u8 +tcp_sack_vector_is_sane (sack_block_t * sacks) +{ + int i; + for (i = 1; i < vec_len (sacks); i++) + { + if (sacks[i - 1].end == sacks[i].start) + return 0; + } + return 1; +} + +/** + * 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 + */ +void +tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end) +{ + sack_block_t *new_list = 0, *block = 0; + 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)) + { + vec_add2 (new_list, block, 1); + block->start = start; + block->end = end; + } + + /* Find the blocks still worth keeping. */ + for (i = 0; i < vec_len (tc->snd_sacks); i++) + { + /* Discard if rcv_nxt advanced beyond current block */ + if (seq_leq (tc->snd_sacks[i].start, tc->rcv_nxt)) + continue; + + /* Merge or drop if segment overlapped by the new segment */ + if (block && (seq_geq (tc->snd_sacks[i].end, new_list[0].start) + && seq_leq (tc->snd_sacks[i].start, new_list[0].end))) + { + if (seq_lt (tc->snd_sacks[i].start, new_list[0].start)) + new_list[0].start = tc->snd_sacks[i].start; + if (seq_lt (new_list[0].end, tc->snd_sacks[i].end)) + new_list[0].end = tc->snd_sacks[i].end; + continue; + } + + /* Save to new SACK list if we have space. */ + if (vec_len (new_list) < TCP_MAX_SACK_BLOCKS) + { + vec_add1 (new_list, tc->snd_sacks[i]); + } + else + { + clib_warning ("sack discarded"); + } + } + + 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; + + /* Segments should not 'touch' */ + ASSERT (tcp_sack_vector_is_sane (tc->snd_sacks)); +} + +/** 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, error = TCP_ERROR_ENQUEUED; + + ASSERT (seq_geq (vnet_buffer (b)->tcp.seq_number, tc->rcv_nxt)); + + /* Pure ACK. Update rcv_nxt and be done. */ + if (PREDICT_FALSE (data_len == 0)) + { + return TCP_ERROR_PURE_ACK; + } + + written = stream_session_enqueue_data (&tc->connection, b, 0, + 1 /* queue event */ , 1); + + TCP_EVT_DBG (TCP_EVT_INPUT, tc, 0, data_len, written); + + /* Update rcv_nxt */ + if (PREDICT_TRUE (written == data_len)) + { + tc->rcv_nxt += written; + } + /* If more data written than expected, account for out-of-order bytes. */ + else if (written > data_len) + { + tc->rcv_nxt += written; + + /* 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. Inform peer */ + tc->flags |= TCP_CONN_SNDACK; + + error = TCP_ERROR_PARTIALLY_ENQUEUED; + } + else + { + tc->flags |= TCP_CONN_SNDACK; + return TCP_ERROR_FIFO_FULL; + } + + /* Update SACK list if need be */ + if (tcp_opts_sack_permitted (&tc->rcv_opts)) + { + /* Remove SACK blocks that have been delivered */ + tcp_update_sack_list (tc, tc->rcv_nxt, tc->rcv_nxt); + } + + return error; +} + +/** 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; + int rv, offset; + + ASSERT (seq_gt (vnet_buffer (b)->tcp.seq_number, tc->rcv_nxt)); + + /* Pure ACK. Do nothing */ + if (PREDICT_FALSE (data_len == 0)) + { + return TCP_ERROR_PURE_ACK; + } + + /* Enqueue out-of-order data with relative offset */ + rv = stream_session_enqueue_data (&tc->connection, b, + vnet_buffer (b)->tcp.seq_number - + tc->rcv_nxt, 0 /* queue event */ , 0); + + /* 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->rcv_opts)) + { + ooo_segment_t *newest; + u32 start, end; + + s0 = stream_session_get (tc->c_s_index, tc->c_thread_index); + + /* Get the newest segment from the fifo */ + newest = svm_fifo_newest_ooo_segment (s0->server_rx_fifo); + if (newest) + { + offset = ooo_segment_offset (s0->server_rx_fifo, newest); + ASSERT (offset <= vnet_buffer (b)->tcp.seq_number - tc->rcv_nxt); + start = tc->rcv_nxt + offset; + end = start + ooo_segment_length (s0->server_rx_fifo, newest); + tcp_update_sack_list (tc, start, end); + svm_fifo_newest_ooo_segment_reset (s0->server_rx_fifo); + } + } + + 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) < 4 * tc->snd_mss) + return 0; + + return 1; +} + +static int +tcp_buffer_discard_bytes (vlib_buffer_t * b, u32 n_bytes_to_drop) +{ + u32 discard, first = b->current_length; + vlib_main_t *vm = vlib_get_main (); + + /* Handle multi-buffer segments */ + if (n_bytes_to_drop > b->current_length) + { + if (!(b->flags & VLIB_BUFFER_NEXT_PRESENT)) + return -1; + do + { + discard = clib_min (n_bytes_to_drop, b->current_length); + vlib_buffer_advance (b, discard); + b = vlib_get_buffer (vm, b->next_buffer); + n_bytes_to_drop -= discard; + } + while (n_bytes_to_drop); + if (n_bytes_to_drop > first) + b->total_length_not_including_first_buffer -= n_bytes_to_drop - first; + } + else + vlib_buffer_advance (b, n_bytes_to_drop); + vnet_buffer (b)->tcp.data_len -= n_bytes_to_drop; + return 0; +} + +static int +tcp_segment_rcv (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b, + u32 * next0) +{ + u32 error = 0, n_bytes_to_drop, n_data_bytes; + + vlib_buffer_advance (b, vnet_buffer (b)->tcp.data_offset); + n_data_bytes = vnet_buffer (b)->tcp.data_len; + ASSERT (n_data_bytes); + + /* 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; + + /* Completely in the past (possible retransmit) */ + if (seq_leq (vnet_buffer (b)->tcp.seq_end, tc->rcv_nxt)) + { + /* Ack retransmissions since we may not have any data to send */ + tcp_make_ack (tc, b); + *next0 = tcp_next_output (tc->c_is_ip4); + goto done; + } + + /* Chop off the bytes in the past */ + n_bytes_to_drop = tc->rcv_nxt - vnet_buffer (b)->tcp.seq_number; + n_data_bytes -= n_bytes_to_drop; + vnet_buffer (b)->tcp.seq_number = tc->rcv_nxt; + if (tcp_buffer_discard_bytes (b, n_bytes_to_drop)) + goto done; + + goto in_order; + } + + 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: + + /* 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); + + /* Check if ACK can be delayed */ + if (tcp_can_delack (tc)) + { + if (!tcp_timer_is_active (tc, TCP_TIMER_DELACK)) + tcp_timer_set (tc, TCP_TIMER_DELACK, TCP_DELACK_TIME); + goto done; + } + + *next0 = tcp_next_output (tc->c_is_ip4); + tcp_make_ack (tc, b); + +done: + return error; +} + +typedef struct +{ + tcp_header_t tcp_header; + tcp_connection_t tcp_connection; +} 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 *); + uword indent = format_get_indent (s); + + s = format (s, "%U\n%U%U", + format_tcp_header, &t->tcp_header, 128, + format_white_space, indent, + format_tcp_connection, &t->tcp_connection, 1); + + return s; +} + +u8 * +format_tcp_rx_trace_short (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, "%d -> %d (%U)", + clib_net_to_host_u16 (t->tcp_header.src_port), + clib_net_to_host_u16 (t->tcp_header.dst_port), format_tcp_state, + t->tcp_connection.state); + + return s; +} + +void +tcp_set_rx_trace_data (tcp_rx_trace_t * t0, tcp_connection_t * tc0, + tcp_header_t * th0, vlib_buffer_t * b0, u8 is_ip4) +{ + if (tc0) + { + clib_memcpy (&t0->tcp_connection, tc0, sizeof (t0->tcp_connection)); + } + else + { + th0 = tcp_buffer_hdr (b0); + } + clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header)); +} + +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->thread_index, errors = 0; + tcp_main_t *tm = vnet_get_tcp_main (); + u8 is_fin = 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 *th0 = 0; + tcp_connection_t *tc0; + 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; + } + + th0 = tcp_buffer_hdr (b0); + /* N.B. buffer is rewritten if segment is ooo. Thus, th0 becomes a + * dangling reference. */ + is_fin = tcp_is_fin (th0); + + /* SYNs, FINs and data consume sequence numbers */ + vnet_buffer (b0)->tcp.seq_end = vnet_buffer (b0)->tcp.seq_number + + tcp_is_syn (th0) + is_fin + vnet_buffer (b0)->tcp.data_len; + + /* 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 */ + if (vnet_buffer (b0)->tcp.data_len) + error0 = tcp_segment_rcv (tm, tc0, b0, &next0); + + /* 8: check the FIN bit */ + if (PREDICT_FALSE (is_fin)) + { + /* Enter CLOSE-WAIT and notify session. To avoid lingering + * in CLOSE-WAIT, set timer (reuse WAITCLOSE). */ + /* Account for the FIN if nothing else was received */ + if (vnet_buffer (b0)->tcp.data_len == 0) + tc0->rcv_nxt += 1; + tcp_make_ack (tc0, b0); + next0 = tcp_next_output (tc0->c_is_ip4); + tc0->state = TCP_STATE_CLOSE_WAIT; + stream_session_disconnect_notify (&tc0->connection); + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_CLOSEWAIT_TIME); + TCP_EVT_DBG (TCP_EVT_FIN_RCVD, tc0); + } + + done: + b0->error = node->errors[error0]; + if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) + { + tcp_rx_trace_t *t0 = + vlib_add_trace (vm, node, b0, sizeof (*t0)); + tcp_set_rx_trace_data (t0, tc0, th0, b0, is_ip4); + } + + 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); + tcp_flush_frame_to_output (vm, my_thread_index, is_ip4); + + 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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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; + +static u8 +tcp_lookup_is_valid (tcp_connection_t * tc, tcp_header_t * hdr) +{ + transport_connection_t *tmp; + if (!tc) + return 1; + + u8 is_valid = (tc->c_lcl_port == hdr->dst_port + && (tc->state == TCP_STATE_LISTEN + || tc->c_rmt_port == hdr->src_port)); + + if (!is_valid) + { + if ((tmp = + stream_session_half_open_lookup (&tc->c_lcl_ip, &tc->c_rmt_ip, + tc->c_lcl_port, tc->c_rmt_port, + tc->c_transport_proto))) + { + if (tmp->lcl_port == hdr->dst_port + && tmp->rmt_port == hdr->src_port) + { + clib_warning ("half-open is valid!"); + } + } + } + return is_valid; +} + +/** + * Lookup transport connection + */ +static tcp_connection_t * +tcp_lookup_connection (vlib_buffer_t * b, u8 thread_index, u8 is_ip4) +{ + tcp_header_t *tcp; + transport_connection_t *tconn; + tcp_connection_t *tc; + if (is_ip4) + { + ip4_header_t *ip4; + ip4 = vlib_buffer_get_current (b); + tcp = ip4_next_header (ip4); + tconn = stream_session_lookup_transport_wt4 (&ip4->dst_address, + &ip4->src_address, + tcp->dst_port, + tcp->src_port, + SESSION_TYPE_IP4_TCP, + thread_index); + tc = tcp_get_connection_from_transport (tconn); + ASSERT (tcp_lookup_is_valid (tc, tcp)); + } + else + { + ip6_header_t *ip6; + ip6 = vlib_buffer_get_current (b); + tcp = ip6_next_header (ip6); + tconn = stream_session_lookup_transport_wt6 (&ip6->dst_address, + &ip6->src_address, + tcp->dst_port, + tcp->src_port, + SESSION_TYPE_IP6_TCP, + thread_index); + tc = tcp_get_connection_from_transport (tconn); + ASSERT (tcp_lookup_is_valid (tc, tcp)); + } + return tc; +} + +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->thread_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, ack0, seq0; + vlib_buffer_t *b0; + tcp_rx_trace_t *t0; + tcp_header_t *tcp0 = 0; + tcp_connection_t *tc0; + 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); + if (PREDICT_FALSE (tc0 == 0)) + { + error0 = TCP_ERROR_INVALID_CONNECTION; + goto drop; + } + + /* Half-open completed recently but the connection was't removed + * yet by the owning thread */ + if (PREDICT_FALSE (tc0->flags & TCP_CONN_HALF_OPEN_DONE)) + { + /* Make sure the connection actually exists */ + ASSERT (tcp_lookup_connection (b0, my_thread_index, is_ip4)); + goto drop; + } + + ack0 = vnet_buffer (b0)->tcp.ack_number; + seq0 = vnet_buffer (b0)->tcp.seq_number; + tcp0 = tcp_buffer_hdr (b0); + + /* Crude check to see if the connection handle does not match + * the packet. Probably connection just switched to established */ + if (PREDICT_FALSE (tcp0->dst_port != tc0->c_lcl_port + || tcp0->src_port != tc0->c_rmt_port)) + goto drop; + + 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) + vnet_buffer (b0)->tcp.data_len; + + /* + * 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 (seq_leq (ack0, tc0->iss) || seq_gt (ack0, tc0->snd_nxt)) + { + clib_warning ("ack not in rcv wnd"); + if (!tcp_rst (tcp0)) + tcp_send_reset_w_pkt (tc0, b0, is_ip4); + goto drop; + } + + /* Make sure ACK is valid */ + if (seq_gt (tc0->snd_una, ack0)) + { + clib_warning ("ack invalid"); + 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)) + tcp_connection_reset (tc0); + goto drop; + } + + /* + * 3. check the security and precedence (skipped) + */ + + /* + * 4. check the SYN bit + */ + + /* No SYN flag. Drop. */ + if (!tcp_syn (tcp0)) + { + clib_warning ("not synack"); + goto drop; + } + + /* Parse options */ + if (tcp_options_parse (tcp0, &tc0->rcv_opts)) + { + clib_warning ("options parse fail"); + goto drop; + } + + /* 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_c_index = new_tc0 - tm->connections[my_thread_index]; + new_tc0->c_thread_index = my_thread_index; + new_tc0->rcv_nxt = vnet_buffer (b0)->tcp.seq_end; + new_tc0->irs = seq0; + new_tc0->timers[TCP_TIMER_ESTABLISH] = TCP_TIMER_HANDLE_INVALID; + new_tc0->timers[TCP_TIMER_RETRANSMIT_SYN] = + TCP_TIMER_HANDLE_INVALID; + + /* If this is not the owning thread, wait for syn retransmit to + * expire and cleanup then */ + if (tcp_half_open_connection_cleanup (tc0)) + tc0->flags |= TCP_CONN_HALF_OPEN_DONE; + + if (tcp_opts_tstamp (&new_tc0->rcv_opts)) + { + new_tc0->tsval_recent = new_tc0->rcv_opts.tsval; + new_tc0->tsval_recent_age = tcp_time_now (); + } + + if (tcp_opts_wscale (&new_tc0->rcv_opts)) + new_tc0->snd_wscale = new_tc0->rcv_opts.wscale; + + /* RFC1323: SYN and SYN-ACK wnd not scaled */ + 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 (PREDICT_TRUE (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. If session layer can't + * allocate session send reset */ + if (stream_session_connect_notify (&new_tc0->connection, 0)) + { + clib_warning ("connect notify fail"); + tcp_send_reset_w_pkt (new_tc0, b0, is_ip4); + tcp_connection_cleanup (new_tc0); + goto drop; + } + + /* Make sure after data segment processing ACK is sent */ + new_tc0->flags |= TCP_CONN_SNDACK; + + /* Update rtt with the syn-ack sample */ + tcp_update_rtt (new_tc0, vnet_buffer (b0)->tcp.ack_number); + TCP_EVT_DBG (TCP_EVT_SYNACK_RCVD, new_tc0); + } + /* 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 */ + if (stream_session_connect_notify (&new_tc0->connection, 0)) + { + tcp_connection_cleanup (new_tc0); + tcp_send_reset_w_pkt (tc0, b0, is_ip4); + TCP_EVT_DBG (TCP_EVT_RST_SENT, tc0); + goto drop; + } + + tc0->rtt_ts = 0; + tcp_init_snd_vars (tc0); + tcp_make_synack (new_tc0, b0); + next0 = tcp_next_output (is_ip4); + + goto drop; + } + + /* Read data, if any */ + if (PREDICT_FALSE (vnet_buffer (b0)->tcp.data_len)) + { + ASSERT (0); + error0 = tcp_segment_rcv (tm, new_tc0, b0, &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) && tcp0 != 0)) + { + t0 = vlib_add_trace (vm, node, b0, sizeof (*t0)); + clib_memcpy (&t0->tcp_header, tcp0, sizeof (t0->tcp_header)); + clib_memcpy (&t0->tcp_connection, tc0, + sizeof (t0->tcp_connection)); + } + + 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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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->thread_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; + u32 next0 = TCP_RCV_PROCESS_NEXT_DROP, error0 = TCP_ERROR_ENQUEUED; + u8 is_fin0; + + 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; + } + + tcp0 = tcp_buffer_hdr (b0); + is_fin0 = tcp_is_fin (tcp0); + + /* SYNs, FINs and data consume sequence numbers */ + vnet_buffer (b0)->tcp.seq_end = vnet_buffer (b0)->tcp.seq_number + + tcp_is_syn (tcp0) + is_fin0 + vnet_buffer (b0)->tcp.data_len; + + if (CLIB_DEBUG) + { + tcp_connection_t *tmp; + tmp = tcp_lookup_connection (b0, my_thread_index, is_ip4); + if (tmp->state != tc0->state) + { + clib_warning ("state changed"); + ASSERT (0); + goto drop; + } + } + + /* + * 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)) + { + clib_warning ("connection not accepted"); + tcp_send_reset_w_pkt (tc0, b0, is_ip4); + goto drop; + } + + /* Update rtt and rto */ + tcp_update_rtt (tc0, vnet_buffer (b0)->tcp.ack_number); + + /* 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->rcv_opts.wscale; + tc0->snd_wl1 = vnet_buffer (b0)->tcp.seq_number; + tc0->snd_wl2 = vnet_buffer (b0)->tcp.ack_number; + stream_session_accept_notify (&tc0->connection); + + /* Reset SYN-ACK retransmit and SYN_RCV establish timers */ + tcp_retransmit_timer_reset (tc0); + tcp_timer_reset (tc0, TCP_TIMER_ESTABLISH); + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, 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; + + /* Still have to send the FIN */ + if (tc0->flags & TCP_CONN_FINPNDG) + { + /* TX fifo finally drained */ + if (!stream_session_tx_fifo_max_dequeue (&tc0->connection)) + tcp_send_fin (tc0); + } + /* If FIN is ACKed */ + else if (tc0->snd_una == tc0->snd_una_max) + { + tc0->state = TCP_STATE_FIN_WAIT_2; + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, tc0); + + /* Stop all retransmit timers because we have nothing more + * to send. Enable waitclose though because we're willing to + * wait for peer's FIN but not indefinitely. */ + tcp_connection_timers_reset (tc0); + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME); + } + 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; + 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; + + tc0->state = TCP_STATE_TIME_WAIT; + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, tc0); + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME); + goto drop; + + break; + case TCP_STATE_LAST_ACK: + /* The only thing that [should] 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->snd_una = vnet_buffer (b0)->tcp.ack_number; + /* Apparently our FIN was lost */ + if (is_fin0) + { + tcp_send_fin (tc0); + goto drop; + } + + tc0->state = TCP_STATE_CLOSED; + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, tc0); + + /* 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); + 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. */ + + if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0)) + goto drop; + + tcp_make_ack (tc0, b0); + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME); + + 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: + if (vnet_buffer (b0)->tcp.data_len) + error0 = tcp_segment_rcv (tm, tc0, b0, &next0); + else if (is_fin0) + tc0->rcv_nxt += 1; + 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 (!is_fin0) + 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); + tc0->snd_nxt += 1; + next0 = tcp_next_output (tc0->c_is_ip4); + stream_session_disconnect_notify (&tc0->connection); + tc0->state = TCP_STATE_CLOSE_WAIT; + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, tc0); + 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_CLOSING; + tcp_make_ack (tc0, b0); + next0 = tcp_next_output (is_ip4); + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, tc0); + /* Wait for ACK but not forever */ + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME); + break; + case TCP_STATE_FIN_WAIT_2: + /* Got FIN, send ACK! Be more aggressive with resource cleanup */ + tc0->state = TCP_STATE_TIME_WAIT; + tcp_connection_timers_reset (tc0); + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_TIMEWAIT_TIME); + tcp_make_ack (tc0, b0); + next0 = tcp_next_output (is_ip4); + TCP_EVT_DBG (TCP_EVT_STATE_CHANGE, tc0); + break; + case TCP_STATE_TIME_WAIT: + /* Remain in the TIME-WAIT state. Restart the time-wait + * timeout. + */ + tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_TIMEWAIT_TIME); + break; + } + TCP_EVT_DBG (TCP_EVT_FIN_RCVD, tc0); + + drop: + b0->error = error0 ? node->errors[error0] : 0; + + if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) + { + tcp_rx_trace_t *t0 = + vlib_add_trace (vm, node, b0, sizeof (*t0)); + tcp_set_rx_trace_data (t0, tc0, tcp0, b0, is_ip4); + } + + 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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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->thread_index; + 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_rx_trace_t *t0; + 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: handled in dispatch */ + /* if (tcp_rst (th0)) + goto drop; */ + + /* 2. second check for an ACK: handled in dispatch */ + /* if (tcp_ack (th0)) + { + tcp_send_reset (b0, is_ip4); + goto drop; + } */ + + /* 3. check for a SYN (did that already) */ + + /* Make sure connection wasn't just created */ + child0 = tcp_lookup_connection (b0, my_thread_index, is_ip4); + if (PREDICT_FALSE (child0->state != TCP_STATE_LISTEN)) + { + error0 = TCP_ERROR_CREATE_EXISTS; + goto drop; + } + + /* Create child session and send SYN-ACK */ + child0 = tcp_connection_new (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->state = TCP_STATE_SYN_RCVD; + + 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 */ )) + { + clib_warning ("session accept fail"); + tcp_connection_cleanup (child0); + error0 = TCP_ERROR_CREATE_SESSION_FAIL; + goto drop; + } + + if (tcp_options_parse (th0, &child0->rcv_opts)) + { + clib_warning ("options parse fail"); + goto drop; + } + + child0->irs = vnet_buffer (b0)->tcp.seq_number; + child0->rcv_nxt = vnet_buffer (b0)->tcp.seq_number + 1; + child0->rcv_las = child0->rcv_nxt; + + /* RFC1323: TSval timestamps sent on {SYN} and {SYN,ACK} + * segments are used to initialize PAWS. */ + if (tcp_opts_tstamp (&child0->rcv_opts)) + { + child0->tsval_recent = child0->rcv_opts.tsval; + child0->tsval_recent_age = tcp_time_now (); + } + + if (tcp_opts_wscale (&child0->rcv_opts)) + child0->snd_wscale = child0->rcv_opts.wscale; + + child0->snd_wnd = clib_net_to_host_u16 (th0->window) + << child0->snd_wscale; + 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, 1); + + /* Reuse buffer to make syn-ack and send */ + tcp_make_synack (child0, b0); + next0 = tcp_next_output (is_ip4); + tcp_timer_set (child0, TCP_TIMER_ESTABLISH, TCP_SYN_RCVD_TIME); + + drop: + if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) + { + t0 = vlib_add_trace (vm, node, b0, sizeof (*t0)); + clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header)); + clib_memcpy (&t0->tcp_connection, lc0, + sizeof (t0->tcp_connection)); + } + + 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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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 _ + }, + .format_trace = format_tcp_rx_trace_short, +}; +/* *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_NEXT_PUNT, + 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") \ + _ (PUNT, "error-punt") + +#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") \ + _ (PUNT, "error-punt") + +#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->thread_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; + tcp_set_time_now (my_thread_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) + { + int n_advance_bytes0, n_data_bytes0; + u32 bi0; + vlib_buffer_t *b0; + tcp_header_t *tcp0 = 0; + tcp_connection_t *tc0; + transport_connection_t *tconn; + 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; + + /* 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; + tconn = stream_session_lookup_transport_wt4 (&ip40->dst_address, + &ip40->src_address, + tcp0->dst_port, + tcp0->src_port, + SESSION_TYPE_IP4_TCP, + my_thread_index); + tc0 = tcp_get_connection_from_transport (tconn); + ASSERT (tcp_lookup_is_valid (tc0, tcp0)); + } + 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]); + tconn = stream_session_lookup_transport_wt6 (&ip60->dst_address, + &ip60->src_address, + tcp0->dst_port, + tcp0->src_port, + SESSION_TYPE_IP6_TCP, + my_thread_index); + tc0 = tcp_get_connection_from_transport (tconn); + ASSERT (tcp_lookup_is_valid (tc0, tcp0)); + } + + /* Length check */ + if (PREDICT_FALSE (n_advance_bytes0 < 0)) + { + error0 = TCP_ERROR_LENGTH; + goto done; + } + + /* 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); + + vnet_buffer (b0)->tcp.hdr_offset = (u8 *) tcp0 + - (u8 *) vlib_buffer_get_current (b0); + vnet_buffer (b0)->tcp.data_offset = n_advance_bytes0; + vnet_buffer (b0)->tcp.data_len = n_data_bytes0; + + 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 + || next0 == TCP_INPUT_NEXT_RESET)) + { + /* Overload tcp flags to store state */ + tcp_state_t state0 = tc0->state; + vnet_buffer (b0)->tcp.flags = tc0->state; + + if (error0 == TCP_ERROR_DISPATCH) + clib_warning ("disp error state %U flags %U", + format_tcp_state, state0, format_tcp_flags, + (int) flags0); + } + } + else + { + if ((is_ip4 && tm->punt_unknown4) || + (!is_ip4 && tm->punt_unknown6)) + { + next0 = TCP_INPUT_NEXT_PUNT; + error0 = TCP_ERROR_PUNT; + } + else + { + /* Send reset */ + next0 = TCP_INPUT_NEXT_RESET; + error0 = TCP_ERROR_NO_LISTENER; + } + } + + done: + b0->error = error0 ? node->errors[error0] : 0; + + if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) + { + tcp_rx_trace_t *t0 = + vlib_add_trace (vm, node, b0, sizeof (*t0)); + tcp_set_rx_trace_data (t0, tc0, tcp0, b0, is_ip4); + } + 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); + +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); + _(LISTEN, TCP_FLAG_ACK, TCP_INPUT_NEXT_RESET, TCP_ERROR_NONE); + _(LISTEN, TCP_FLAG_RST, TCP_INPUT_NEXT_DROP, TCP_ERROR_NONE); + _(LISTEN, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RESET, + 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_RCVD, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(SYN_RCVD, TCP_FLAG_SYN, 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); + _(ESTABLISHED, TCP_FLAG_RST | TCP_FLAG_ACK, TCP_INPUT_NEXT_ESTABLISHED, + TCP_ERROR_NONE); + _(ESTABLISHED, TCP_FLAG_SYN, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE); + _(ESTABLISHED, TCP_FLAG_SYN | TCP_FLAG_ACK, 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_WAIT_1, TCP_FLAG_RST, 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_ACK, 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); + _(CLOSE_WAIT, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(CLOSE_WAIT, 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); + _(LAST_ACK, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(LAST_ACK, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, + TCP_ERROR_NONE); + _(LAST_ACK, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(TIME_WAIT, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(TIME_WAIT, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, + TCP_ERROR_NONE); + _(TIME_WAIT, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(TIME_WAIT, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE); + _(CLOSED, TCP_FLAG_ACK, TCP_INPUT_NEXT_DROP, TCP_ERROR_CONNECTION_CLOSED); + _(CLOSED, TCP_FLAG_RST, TCP_INPUT_NEXT_DROP, TCP_ERROR_CONNECTION_CLOSED); + _(CLOSED, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_DROP, + TCP_ERROR_CONNECTION_CLOSED); +#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: + */ |