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gerrit.nordix.org / fdio / vpp / 06d110189e54220c533c5fe0cea7f23e531284b9 / . / src / vnet / tcp / tcp_input.c
blob: 9d3f4cc39e997964701b12518f50d3e049430bb3 [file] [log] [blame]
/*
* 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 + 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;
}
}
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->opt) && tc->tsval_recent
&& timestamp_lt (tc->opt.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->opt) && tc->tsval_recent
&& seq_leq (seq, tc->rcv_las) && seq_leq (tc->rcv_las, seq_end))
{
tc->tsval_recent = tc->opt.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->opt)))
{
return -1;
}
if (tcp_segment_check_paws (tc0))
{
clib_warning ("paws failed");
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))
{
tcp_send_reset (b0, 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;
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;
u8 rtx_acked;
/* Determine if only rtx bytes are acked. TODO fast retransmit */
rtx_acked = tc->rto_boff && (tc->bytes_acked <= tc->snd_mss);
/* Karn's rule, part 1. Don't use retransmitted segments to estimate
* RTT because they're ambiguous. */
if (tc->rtt_ts && seq_geq (ack, tc->rtt_seq) && !rtx_acked)
{
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). 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;
}
/* Allow measuring of a new RTT */
tc->rtt_ts = 0;
/* If ACK moves left side of the wnd make sure boff is 0, even if mrtt is
* not valid */
if (tc->bytes_acked)
tc->rto_boff = 0;
/* 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 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 bytes */
stream_session_dequeue_drop (&tc->connection, tc->bytes_acked);
/* Update rtt and rto */
tcp_update_rtt (tc, ack);
}
/**
* 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, delivered_bytes, hole_index;
int i, j;
sb->last_sacked_bytes = 0;
sb->snd_una_adv = 0;
old_sacked_bytes = sb->sacked_bytes;
delivered_bytes = 0;
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);
tmp = tc->opt.sacks[vec_len (tc->opt.sacks) - 1];
sb->max_byte_sacked = tmp.end;
}
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))
delivered_bytes += next_hole->start - hole->end;
else
delivered_bytes += ack - hole->end;
}
else
{
sb->sacked_bytes += scoreboard_hole_bytes (hole);
}
/* 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 for when the last hole
* is acked */
if (seq_gt (hole->end, sb->max_byte_sacked))
sb->max_byte_sacked = hole->end;
}
/* snd_una needs to be advanced */
if (blk->end == ack && seq_geq (ack, hole->end))
{
if (next_hole && seq_lt (ack, next_hole->start))
{
sb->snd_una_adv = next_hole->start - ack;
/* all these can be delivered */
delivered_bytes += sb->snd_una_adv;
}
else if (!next_hole)
{
sb->snd_una_adv = sb->max_byte_sacked - ack;
delivered_bytes += sb->snd_una_adv;
}
}
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 - old_sacked_bytes;
sb->sacked_bytes -= delivered_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);
/* Set probe timer if we just got 0 wnd */
if (tc->snd_wnd < tc->snd_mss
&& !tcp_timer_is_active (tc, TCP_TIMER_PERSIST))
tcp_persist_timer_set (tc);
else
tcp_persist_timer_reset (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)
{
/* TODO: check if time to recover was small. It might be that RTO popped
* too soon.
*/
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_cong_recovery_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_fastrecovery (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_max;
/* XXX need proper RFC6675 support */
if (tc->sack_sb.last_sacked_bytes && !tcp_in_recovery (tc))
{
tcp_fast_retransmit (tc);
}
else
{
/* Retransmit first unacked segment */
tcp_retransmit_first_unacked (tc);
}
}
}
else
{
tc->cc_algo->rcv_ack (tc);
tc->tsecr_last_ack = tc->opt.tsecr;
tc->rcv_dupacks = 0;
if (tcp_in_recovery (tc))
{
tc->rtx_bytes -= clib_min (tc->bytes_acked, tc->rtx_bytes);
tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
if (seq_geq (tc->snd_una, tc->snd_congestion))
tcp_recovery_off (tc);
}
}
}
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;
}
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 (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);
}
/* Don't drop yet */
return 0;
}
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);
/* 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
*/
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]);
}
}
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, 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 = 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. Inform peer */
tc->flags |= TCP_CONN_SNDACK;
return 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->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;
int rv;
/* Pure ACK. Do nothing */
if (PREDICT_FALSE (data_len == 0))
{
return TCP_ERROR_PURE_ACK;
}
/* Enqueue out-of-order data with absolute offset */
rv = stream_session_enqueue_data (&tc->connection, b,
vnet_buffer (b)->tcp.seq_number,
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->opt))
{
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);
start = ooo_segment_offset (s0->server_rx_fifo, newest);
end = 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, n_bytes_to_drop;
/* 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_lt (vnet_buffer (b)->tcp.seq_end, tc->rcv_nxt))
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;
vlib_buffer_advance (b, n_bytes_to_drop);
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);
if (n_data_bytes == 0)
{
*next0 = TCP_NEXT_DROP;
goto done;
}
/* 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_verbose, &t->tcp_connection);
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);
is_fin = (th0->flags & TCP_FLAG_FIN) != 0;
/* 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 */
vlib_buffer_advance (b0, vnet_buffer (b0)->tcp.data_offset);
error0 = tcp_segment_rcv (tm, tc0, b0,
vnet_buffer (b0)->tcp.data_len, &next0);
/* N.B. buffer is rewritten if segment is ooo. Thus, th0 becomes a
* dangling reference. */
/* 8: check the FIN bit */
if (is_fin)
{
/* 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))
{
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);
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;
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;
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_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);
ack0 = vnet_buffer (b0)->tcp.ack_number;
seq0 = vnet_buffer (b0)->tcp.seq_number;
tcp0 = tcp_buffer_hdr (b0);
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 (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;
new_tc0->c_c_index = new_tc0 - tm->connections[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 */
if (tcp_options_parse (tcp0, &new_tc0->opt))
goto drop;
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);
stream_session_init_fifos_pointers (&new_tc0->connection,
new_tc0->irs + 1,
new_tc0->iss + 1);
/* 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);
stream_session_init_fifos_pointers (&new_tc0->connection,
new_tc0->irs + 1,
new_tc0->iss + 1);
tcp_make_synack (new_tc0, b0);
next0 = tcp_next_output (is_ip4);
goto drop;
}
/* Read data, if any */
if (vnet_buffer (b0)->tcp.data_len)
{
vlib_buffer_advance (b0, vnet_buffer (b0)->tcp.data_offset);
error0 = tcp_segment_rcv (tm, new_tc0, b0,
vnet_buffer (b0)->tcp.data_len,
&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))
{
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;
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);
/* 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)
+ vnet_buffer (b0)->tcp.data_len;
/*
* 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;
}
/* Update rtt and rto */
tc0->bytes_acked = 1;
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->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:
vlib_buffer_advance (b0, vnet_buffer (b0)->tcp.data_offset);
error0 = tcp_segment_rcv (tm, tc0, b0,
vnet_buffer (b0)->tcp.data_len,
&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_connection_timers_reset (tc0);
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);
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;
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_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) */
/* 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;
}
if (tcp_options_parse (th0, &child0->opt))
{
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;
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);
/* Init fifo pointers after we have iss */
stream_session_init_fifos_pointers (&child0->connection,
child0->irs + 1,
child0->iss + 1);
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_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")
#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;
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;
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;
/* 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);
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]);
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);
}
/* 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
{
/* 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);
/* 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-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);
/* 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_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);
_(LAST_ACK, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(CLOSED, TCP_FLAG_ACK, TCP_INPUT_NEXT_RESET, TCP_ERROR_CONNECTION_CLOSED);
_(CLOSED, TCP_FLAG_RST, 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:
*/