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cb711a4ec908b89edc9da29d3c2e093dab85fbbf
vpp/src/vnet/tcp/tcp_output.c
Florin Coras cb711a4ec9 tcp: avoid sending acks when data available 
Type: fix

Change-Id: I02e2cb2d349f9ddb2bfed040a08ca448f379d565
Signed-off-by: Florin Coras <fcoras@cisco.com>
2019-10-17 18:42:18 +00:00

2696 lines
71 KiB
C
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/*
* Copyright (c) 2016-2019 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 <vnet/tcp/tcp.h>
#include <math.h>
typedef enum _tcp_output_next
{
TCP_OUTPUT_NEXT_DROP,
TCP_OUTPUT_NEXT_IP_LOOKUP,
TCP_OUTPUT_NEXT_IP_REWRITE,
TCP_OUTPUT_NEXT_IP_ARP,
TCP_OUTPUT_N_NEXT
} tcp_output_next_t;
#define foreach_tcp4_output_next \
_ (DROP, "error-drop") \
_ (IP_LOOKUP, "ip4-lookup") \
_ (IP_REWRITE, "ip4-rewrite") \
_ (IP_ARP, "ip4-arp")
#define foreach_tcp6_output_next \
_ (DROP, "error-drop") \
_ (IP_LOOKUP, "ip6-lookup") \
_ (IP_REWRITE, "ip6-rewrite") \
_ (IP_ARP, "ip6-discover-neighbor")
static char *tcp_error_strings[] = {
#define tcp_error(n,s) s,
#include <vnet/tcp/tcp_error.def>
#undef tcp_error
};
typedef struct
{
tcp_header_t tcp_header;
tcp_connection_t tcp_connection;
} tcp_tx_trace_t;
static u8 *
format_tcp_tx_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_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *);
u32 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;
}
#ifndef CLIB_MARCH_VARIANT
static u8
tcp_window_compute_scale (u32 window)
{
u8 wnd_scale = 0;
while (wnd_scale < TCP_MAX_WND_SCALE && (window >> wnd_scale) > TCP_WND_MAX)
wnd_scale++;
return wnd_scale;
}
/**
* TCP's initial window
*/
always_inline u32
tcp_initial_wnd_unscaled (tcp_connection_t * tc)
{
/* RFC 6928 recommends the value lower. However at the time our connections
* are initialized, fifos may not be allocated. Therefore, advertise the
* smallest possible unscaled window size and update once fifos are
* assigned to the session.
*/
/*
tcp_update_rcv_mss (tc);
TCP_IW_N_SEGMENTS * tc->mss;
*/
return tcp_cfg.min_rx_fifo;
}
/**
* Compute initial window and scale factor. As per RFC1323, window field in
* SYN and SYN-ACK segments is never scaled.
*/
u32
tcp_initial_window_to_advertise (tcp_connection_t * tc)
{
/* Compute rcv wscale only if peer advertised support for it */
if (tc->state != TCP_STATE_SYN_RCVD || tcp_opts_wscale (&tc->rcv_opts))
tc->rcv_wscale = tcp_window_compute_scale (tcp_cfg.max_rx_fifo);
tc->rcv_wnd = tcp_initial_wnd_unscaled (tc);
return clib_min (tc->rcv_wnd, TCP_WND_MAX);
}
static inline void
tcp_update_rcv_wnd (tcp_connection_t * tc)
{
u32 available_space, wnd;
i32 observed_wnd;
ASSERT (tc->rcv_opts.mss < transport_rx_fifo_size (&tc->connection));
/*
* Figure out how much space we have available
*/
available_space = transport_max_rx_enqueue (&tc->connection);
if (PREDICT_FALSE (available_space < tc->rcv_opts.mss))
{
tc->rcv_wnd = 0;
return;
}
/*
* Use the above and what we know about what we've previously advertised
* to compute the new window
*/
observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las);
/* Bad. Thou shalt not shrink */
if (PREDICT_FALSE ((i32) available_space < observed_wnd))
{
wnd = clib_max (observed_wnd, 0);
TCP_EVT (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
}
else
{
wnd = available_space;
}
/* Make sure we have a multiple of rcv_wscale */
if (wnd && tc->rcv_wscale)
{
wnd &= ~((1 << tc->rcv_wscale) - 1);
if (wnd == 0)
wnd = 1 << tc->rcv_wscale;
}
tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
}
/**
* Compute and return window to advertise, scaled as per RFC1323
*/
static inline u32
tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
{
if (state < TCP_STATE_ESTABLISHED)
return tcp_initial_window_to_advertise (tc);
tcp_update_rcv_wnd (tc);
return tc->rcv_wnd >> tc->rcv_wscale;
}
/**
* Write TCP options to segment.
*/
static u32
tcp_options_write (u8 * data, tcp_options_t * opts)
{
u32 opts_len = 0;
u32 buf, seq_len = 4;
if (tcp_opts_mss (opts))
{
*data++ = TCP_OPTION_MSS;
*data++ = TCP_OPTION_LEN_MSS;
buf = clib_host_to_net_u16 (opts->mss);
clib_memcpy_fast (data, &buf, sizeof (opts->mss));
data += sizeof (opts->mss);
opts_len += TCP_OPTION_LEN_MSS;
}
if (tcp_opts_wscale (opts))
{
*data++ = TCP_OPTION_WINDOW_SCALE;
*data++ = TCP_OPTION_LEN_WINDOW_SCALE;
*data++ = opts->wscale;
opts_len += TCP_OPTION_LEN_WINDOW_SCALE;
}
if (tcp_opts_sack_permitted (opts))
{
*data++ = TCP_OPTION_SACK_PERMITTED;
*data++ = TCP_OPTION_LEN_SACK_PERMITTED;
opts_len += TCP_OPTION_LEN_SACK_PERMITTED;
}
if (tcp_opts_tstamp (opts))
{
*data++ = TCP_OPTION_TIMESTAMP;
*data++ = TCP_OPTION_LEN_TIMESTAMP;
buf = clib_host_to_net_u32 (opts->tsval);
clib_memcpy_fast (data, &buf, sizeof (opts->tsval));
data += sizeof (opts->tsval);
buf = clib_host_to_net_u32 (opts->tsecr);
clib_memcpy_fast (data, &buf, sizeof (opts->tsecr));
data += sizeof (opts->tsecr);
opts_len += TCP_OPTION_LEN_TIMESTAMP;
}
if (tcp_opts_sack (opts))
{
int i;
if (opts->n_sack_blocks != 0)
{
*data++ = TCP_OPTION_SACK_BLOCK;
*data++ = 2 + opts->n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
for (i = 0; i < opts->n_sack_blocks; i++)
{
buf = clib_host_to_net_u32 (opts->sacks[i].start);
clib_memcpy_fast (data, &buf, seq_len);
data += seq_len;
buf = clib_host_to_net_u32 (opts->sacks[i].end);
clib_memcpy_fast (data, &buf, seq_len);
data += seq_len;
}
opts_len += 2 + opts->n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
}
}
/* Terminate TCP options */
if (opts_len % 4)
{
*data++ = TCP_OPTION_EOL;
opts_len += TCP_OPTION_LEN_EOL;
}
/* Pad with zeroes to a u32 boundary */
while (opts_len % 4)
{
*data++ = TCP_OPTION_NOOP;
opts_len += TCP_OPTION_LEN_NOOP;
}
return opts_len;
}
static int
tcp_make_syn_options (tcp_connection_t * tc, tcp_options_t * opts)
{
u8 len = 0;
opts->flags |= TCP_OPTS_FLAG_MSS;
opts->mss = tc->mss;
len += TCP_OPTION_LEN_MSS;
opts->flags |= TCP_OPTS_FLAG_WSCALE;
opts->wscale = tc->rcv_wscale;
len += TCP_OPTION_LEN_WINDOW_SCALE;
opts->flags |= TCP_OPTS_FLAG_TSTAMP;
opts->tsval = tcp_time_now ();
opts->tsecr = 0;
len += TCP_OPTION_LEN_TIMESTAMP;
if (TCP_USE_SACKS)
{
opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
len += TCP_OPTION_LEN_SACK_PERMITTED;
}
/* Align to needed boundary */
len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
return len;
}
static int
tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
{
u8 len = 0;
opts->flags |= TCP_OPTS_FLAG_MSS;
opts->mss = tc->mss;
len += TCP_OPTION_LEN_MSS;
if (tcp_opts_wscale (&tc->rcv_opts))
{
opts->flags |= TCP_OPTS_FLAG_WSCALE;
opts->wscale = tc->rcv_wscale;
len += TCP_OPTION_LEN_WINDOW_SCALE;
}
if (tcp_opts_tstamp (&tc->rcv_opts))
{
opts->flags |= TCP_OPTS_FLAG_TSTAMP;
opts->tsval = tcp_time_now ();
opts->tsecr = tc->tsval_recent;
len += TCP_OPTION_LEN_TIMESTAMP;
}
if (tcp_opts_sack_permitted (&tc->rcv_opts))
{
opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
len += TCP_OPTION_LEN_SACK_PERMITTED;
}
/* Align to needed boundary */
len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
return len;
}
static int
tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
{
u8 len = 0;
opts->flags = 0;
if (tcp_opts_tstamp (&tc->rcv_opts))
{
opts->flags |= TCP_OPTS_FLAG_TSTAMP;
opts->tsval = tcp_tstamp (tc);
opts->tsecr = tc->tsval_recent;
len += TCP_OPTION_LEN_TIMESTAMP;
}
if (tcp_opts_sack_permitted (&tc->rcv_opts))
{
if (vec_len (tc->snd_sacks))
{
opts->flags |= TCP_OPTS_FLAG_SACK;
if (tc->snd_sack_pos >= vec_len (tc->snd_sacks))
tc->snd_sack_pos = 0;
opts->sacks = &tc->snd_sacks[tc->snd_sack_pos];
opts->n_sack_blocks = vec_len (tc->snd_sacks) - tc->snd_sack_pos;
opts->n_sack_blocks = clib_min (opts->n_sack_blocks,
TCP_OPTS_MAX_SACK_BLOCKS);
tc->snd_sack_pos += opts->n_sack_blocks;
len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks;
}
}
/* Align to needed boundary */
len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
return len;
}
always_inline int
tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
tcp_state_t state)
{
switch (state)
{
case TCP_STATE_ESTABLISHED:
case TCP_STATE_CLOSE_WAIT:
case TCP_STATE_FIN_WAIT_1:
case TCP_STATE_LAST_ACK:
case TCP_STATE_CLOSING:
case TCP_STATE_FIN_WAIT_2:
case TCP_STATE_TIME_WAIT:
case TCP_STATE_CLOSED:
return tcp_make_established_options (tc, opts);
case TCP_STATE_SYN_RCVD:
return tcp_make_synack_options (tc, opts);
case TCP_STATE_SYN_SENT:
return tcp_make_syn_options (tc, opts);
default:
clib_warning ("State not handled! %d", state);
return 0;
}
}
/**
* Update burst send vars
*
* - Updates snd_mss to reflect the effective segment size that we can send
* by taking into account all TCP options, including SACKs.
* - Cache 'on the wire' options for reuse
* - Updates receive window which can be reused for a burst.
*
* This should *only* be called when doing bursts
*/
void
tcp_update_burst_snd_vars (tcp_connection_t * tc)
{
tcp_main_t *tm = &tcp_main;
/* Compute options to be used for connection. These may be reused when
* sending data or to compute the effective mss (snd_mss) */
tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts,
TCP_STATE_ESTABLISHED);
/* XXX check if MTU has been updated */
tc->snd_mss = clib_min (tc->mss, tc->rcv_opts.mss) - tc->snd_opts_len;
ASSERT (tc->snd_mss > 0);
tcp_options_write (tm->wrk_ctx[tc->c_thread_index].cached_opts,
&tc->snd_opts);
tcp_update_rcv_wnd (tc);
if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
tc->flags |= TCP_CONN_TRACK_BURST;
if (tc->snd_una == tc->snd_nxt)
{
tcp_cc_event (tc, TCP_CC_EVT_START_TX);
tcp_connection_tx_pacer_reset (tc, tc->cwnd, TRANSPORT_PACER_MIN_MSS);
}
}
#endif /* CLIB_MARCH_VARIANT */
static void *
tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
{
if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
vlib_buffer_free_one (vm, b->next_buffer);
/* Zero all flags but free list index and trace flag */
b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1;
b->current_data = 0;
b->current_length = 0;
b->total_length_not_including_first_buffer = 0;
vnet_buffer (b)->tcp.flags = 0;
/* Leave enough space for headers */
return vlib_buffer_make_headroom (b, TRANSPORT_MAX_HDRS_LEN);
}
#ifndef CLIB_MARCH_VARIANT
static void *
tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
{
ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
b->total_length_not_including_first_buffer = 0;
b->current_data = 0;
vnet_buffer (b)->tcp.flags = 0;
VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b);
/* Leave enough space for headers */
return vlib_buffer_make_headroom (b, TRANSPORT_MAX_HDRS_LEN);
}
/* Compute TCP checksum in software when offloading is disabled for a connection */
u16
ip6_tcp_compute_checksum_custom (vlib_main_t * vm, vlib_buffer_t * p0,
ip46_address_t * src, ip46_address_t * dst)
{
ip_csum_t sum0;
u16 payload_length_host_byte_order;
u32 i;
/* Initialize checksum with ip header. */
sum0 = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, p0)) +
clib_host_to_net_u16 (IP_PROTOCOL_TCP);
payload_length_host_byte_order = vlib_buffer_length_in_chain (vm, p0);
for (i = 0; i < ARRAY_LEN (src->ip6.as_uword); i++)
{
sum0 = ip_csum_with_carry
(sum0, clib_mem_unaligned (&src->ip6.as_uword[i], uword));
sum0 = ip_csum_with_carry
(sum0, clib_mem_unaligned (&dst->ip6.as_uword[i], uword));
}
return ip_calculate_l4_checksum (vm, p0, sum0,
payload_length_host_byte_order, NULL, 0,
NULL);
}
u16
ip4_tcp_compute_checksum_custom (vlib_main_t * vm, vlib_buffer_t * p0,
ip46_address_t * src, ip46_address_t * dst)
{
ip_csum_t sum0;
u32 payload_length_host_byte_order;
payload_length_host_byte_order = vlib_buffer_length_in_chain (vm, p0);
sum0 =
clib_host_to_net_u32 (payload_length_host_byte_order +
(IP_PROTOCOL_TCP << 16));
sum0 = ip_csum_with_carry (sum0, clib_mem_unaligned (&src->ip4, u32));
sum0 = ip_csum_with_carry (sum0, clib_mem_unaligned (&dst->ip4, u32));
return ip_calculate_l4_checksum (vm, p0, sum0,
payload_length_host_byte_order, NULL, 0,
NULL);
}
static inline u16
tcp_compute_checksum (tcp_connection_t * tc, vlib_buffer_t * b)
{
u16 checksum = 0;
if (PREDICT_FALSE (tc->cfg_flags & TCP_CFG_F_NO_CSUM_OFFLOAD))
{
tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
vlib_main_t *vm = wrk->vm;
if (tc->c_is_ip4)
checksum = ip4_tcp_compute_checksum_custom
(vm, b, &tc->c_lcl_ip, &tc->c_rmt_ip);
else
checksum = ip6_tcp_compute_checksum_custom
(vm, b, &tc->c_lcl_ip, &tc->c_rmt_ip);
}
else
{
b->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
}
return checksum;
}
/**
* Prepare ACK
*/
static inline void
tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
u8 flags)
{
tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
u8 tcp_opts_len, tcp_hdr_opts_len;
tcp_header_t *th;
u16 wnd;
wnd = tcp_window_to_advertise (tc, state);
/* Make and write options */
tcp_opts_len = tcp_make_established_options (tc, snd_opts);
tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
tcp_options_write ((u8 *) (th + 1), snd_opts);
th->checksum = tcp_compute_checksum (tc, b);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
if (wnd == 0)
tcp_zero_rwnd_sent_on (tc);
else
tcp_zero_rwnd_sent_off (tc);
}
/**
* Convert buffer to ACK
*/
static inline void
tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
{
tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
TCP_EVT (TCP_EVT_ACK_SENT, tc);
tc->rcv_las = tc->rcv_nxt;
}
/**
* Convert buffer to FIN-ACK
*/
void
tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
{
tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_FIN | TCP_FLAG_ACK);
}
/**
* Convert buffer to SYN
*/
void
tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
{
u8 tcp_hdr_opts_len, tcp_opts_len;
tcp_header_t *th;
u16 initial_wnd;
tcp_options_t snd_opts;
initial_wnd = tcp_initial_window_to_advertise (tc);
/* Make and write options */
clib_memset (&snd_opts, 0, sizeof (snd_opts));
tcp_opts_len = tcp_make_syn_options (tc, &snd_opts);
tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
initial_wnd);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
tcp_options_write ((u8 *) (th + 1), &snd_opts);
th->checksum = tcp_compute_checksum (tc, b);
}
/**
* Convert buffer to SYN-ACK
*/
void
tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
{
tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
u8 tcp_opts_len, tcp_hdr_opts_len;
tcp_header_t *th;
u16 initial_wnd;
clib_memset (snd_opts, 0, sizeof (*snd_opts));
initial_wnd = tcp_initial_window_to_advertise (tc);
tcp_opts_len = tcp_make_synack_options (tc, snd_opts);
tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
tc->rcv_nxt, tcp_hdr_opts_len,
TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd);
tcp_options_write ((u8 *) (th + 1), snd_opts);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
th->checksum = tcp_compute_checksum (tc, b);
}
always_inline void
tcp_enqueue_to_ip_lookup_i (tcp_worker_ctx_t * wrk, vlib_buffer_t * b, u32 bi,
u8 is_ip4, u32 fib_index, u8 flush)
{
vlib_main_t *vm = wrk->vm;
u32 *to_next, next_index;
vlib_frame_t *f;
b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
b->error = 0;
vnet_buffer (b)->sw_if_index[VLIB_TX] = fib_index;
vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
/* Send to IP lookup */
next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
tcp_trajectory_add_start (b, 1);
f = wrk->ip_lookup_tx_frames[!is_ip4];
if (!f)
{
f = vlib_get_frame_to_node (vm, next_index);
ASSERT (f);
wrk->ip_lookup_tx_frames[!is_ip4] = f;
}
to_next = vlib_frame_vector_args (f);
to_next[f->n_vectors] = bi;
f->n_vectors += 1;
if (flush || f->n_vectors == VLIB_FRAME_SIZE)
{
vlib_put_frame_to_node (vm, next_index, f);
wrk->ip_lookup_tx_frames[!is_ip4] = 0;
}
}
static void
tcp_enqueue_to_ip_lookup_now (tcp_worker_ctx_t * wrk, vlib_buffer_t * b,
u32 bi, u8 is_ip4, u32 fib_index)
{
tcp_enqueue_to_ip_lookup_i (wrk, b, bi, is_ip4, fib_index, 1);
}
static void
tcp_enqueue_to_ip_lookup (tcp_worker_ctx_t * wrk, vlib_buffer_t * b, u32 bi,
u8 is_ip4, u32 fib_index)
{
tcp_enqueue_to_ip_lookup_i (wrk, b, bi, is_ip4, fib_index, 0);
if (wrk->vm->thread_index == 0 && vlib_num_workers ())
session_flush_frames_main_thread (wrk->vm);
}
always_inline void
tcp_enqueue_to_output_i (tcp_worker_ctx_t * wrk, vlib_buffer_t * b, u32 bi,
u8 is_ip4, u8 flush)
{
u32 *to_next, next_index;
vlib_frame_t *f;
b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
b->error = 0;
/* Decide where to send the packet */
next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
tcp_trajectory_add_start (b, 2);
/* Get frame to v4/6 output node */
f = wrk->tx_frames[!is_ip4];
if (!f)
{
f = vlib_get_frame_to_node (wrk->vm, next_index);
ASSERT (f);
wrk->tx_frames[!is_ip4] = f;
}
to_next = vlib_frame_vector_args (f);
to_next[f->n_vectors] = bi;
f->n_vectors += 1;
if (flush || f->n_vectors == VLIB_FRAME_SIZE)
{
vlib_put_frame_to_node (wrk->vm, next_index, f);
wrk->tx_frames[!is_ip4] = 0;
}
}
static void
tcp_enqueue_to_output (tcp_worker_ctx_t * wrk, vlib_buffer_t * b, u32 bi,
u8 is_ip4)
{
tcp_enqueue_to_output_i (wrk, b, bi, is_ip4, 0);
}
static void
tcp_enqueue_to_output_now (tcp_worker_ctx_t * wrk, vlib_buffer_t * b, u32 bi,
u8 is_ip4)
{
tcp_enqueue_to_output_i (wrk, b, bi, is_ip4, 1);
}
#endif /* CLIB_MARCH_VARIANT */
static int
tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
tcp_state_t state, u8 thread_index, u8 is_ip4)
{
ip4_header_t *ih4;
ip6_header_t *ih6;
tcp_header_t *th0;
ip4_address_t src_ip40, dst_ip40;
ip6_address_t src_ip60, dst_ip60;
u16 src_port, dst_port;
u32 tmp;
u32 seq, ack;
u8 flags;
/* Find IP and TCP headers */
th0 = tcp_buffer_hdr (b0);
/* Save src and dst ip */
if (is_ip4)
{
ih4 = vlib_buffer_get_current (b0);
ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
src_ip40.as_u32 = ih4->src_address.as_u32;
dst_ip40.as_u32 = ih4->dst_address.as_u32;
}
else
{
ih6 = vlib_buffer_get_current (b0);
ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
clib_memcpy_fast (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
clib_memcpy_fast (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
}
src_port = th0->src_port;
dst_port = th0->dst_port;
/* Try to determine what/why we're actually resetting */
if (state == TCP_STATE_CLOSED)
{
if (!tcp_syn (th0))
return -1;
tmp = clib_net_to_host_u32 (th0->seq_number);
/* Got a SYN for no listener. */
flags = TCP_FLAG_RST | TCP_FLAG_ACK;
ack = clib_host_to_net_u32 (tmp + 1);
seq = 0;
}
else
{
flags = TCP_FLAG_RST;
seq = th0->ack_number;
ack = 0;
}
tcp_reuse_buffer (vm, b0);
tcp_trajectory_add_start (b0, 4);
th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
sizeof (tcp_header_t), flags, 0);
if (is_ip4)
{
ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
IP_PROTOCOL_TCP, 1);
th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
}
else
{
int bogus = ~0;
ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
IP_PROTOCOL_TCP);
th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
ASSERT (!bogus);
}
return 0;
}
#ifndef CLIB_MARCH_VARIANT
/**
* Send reset without reusing existing buffer
*
* It extracts connection info out of original packet
*/
void
tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt,
u32 thread_index, u8 is_ip4)
{
tcp_worker_ctx_t *wrk = tcp_get_worker (thread_index);
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi, sw_if_index, fib_index;
u8 tcp_hdr_len, flags = 0;
tcp_header_t *th, *pkt_th;
u32 seq, ack;
ip4_header_t *ih4, *pkt_ih4;
ip6_header_t *ih6, *pkt_ih6;
fib_protocol_t fib_proto;
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
return;
b = vlib_get_buffer (vm, bi);
sw_if_index = vnet_buffer (pkt)->sw_if_index[VLIB_RX];
fib_proto = is_ip4 ? FIB_PROTOCOL_IP4 : FIB_PROTOCOL_IP6;
fib_index = fib_table_get_index_for_sw_if_index (fib_proto, sw_if_index);
tcp_init_buffer (vm, b);
/* Make and write options */
tcp_hdr_len = sizeof (tcp_header_t);
if (is_ip4)
{
pkt_ih4 = vlib_buffer_get_current (pkt);
pkt_th = ip4_next_header (pkt_ih4);
}
else
{
pkt_ih6 = vlib_buffer_get_current (pkt);
pkt_th = ip6_next_header (pkt_ih6);
}
if (tcp_ack (pkt_th))
{
flags = TCP_FLAG_RST;
seq = pkt_th->ack_number;
ack = (tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
}
else
{
flags = TCP_FLAG_RST | TCP_FLAG_ACK;
seq = 0;
ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
}
th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
seq, ack, tcp_hdr_len, flags, 0);
/* Swap src and dst ip */
if (is_ip4)
{
ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
&pkt_ih4->src_address, IP_PROTOCOL_TCP,
tcp_csum_offload (tc));
th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
}
else
{
int bogus = ~0;
ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
0x60);
ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
&pkt_ih6->src_address, IP_PROTOCOL_TCP);
th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
ASSERT (!bogus);
}
tcp_enqueue_to_ip_lookup_now (wrk, b, bi, is_ip4, fib_index);
TCP_EVT (TCP_EVT_RST_SENT, tc);
vlib_node_increment_counter (vm, tcp_node_index (output, tc->c_is_ip4),
TCP_ERROR_RST_SENT, 1);
}
/**
* Build and set reset packet for connection
*/
void
tcp_send_reset (tcp_connection_t * tc)
{
tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi;
tcp_header_t *th;
u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
u8 flags;
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
return;
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
flags = TCP_FLAG_RST;
th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
tc->rcv_nxt, tcp_hdr_opts_len, flags,
advertise_wnd);
opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
th->checksum = tcp_compute_checksum (tc, b);
ASSERT (opts_write_len == tc->snd_opts_len);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
TCP_EVT (TCP_EVT_RST_SENT, tc);
vlib_node_increment_counter (vm, tcp_node_index (output, tc->c_is_ip4),
TCP_ERROR_RST_SENT, 1);
}
static void
tcp_push_ip_hdr (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
vlib_buffer_t * b)
{
tcp_header_t *th = vlib_buffer_get_current (b);
vlib_main_t *vm = wrk->vm;
if (tc->c_is_ip4)
{
ip4_header_t *ih;
ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
&tc->c_rmt_ip4, IP_PROTOCOL_TCP,
tcp_csum_offload (tc));
th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
}
else
{
ip6_header_t *ih;
int bogus = ~0;
ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
&tc->c_rmt_ip6, IP_PROTOCOL_TCP);
th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
ASSERT (!bogus);
}
}
/**
* Send SYN
*
* Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
* The packet is not forwarded through tcpx_output to avoid doing lookups
* in the half_open pool.
*/
void
tcp_send_syn (tcp_connection_t * tc)
{
tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi;
/*
* Setup retransmit and establish timers before requesting buffer
* such that we can return if we've ran out.
*/
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
tc->rto * TCP_TO_TIMER_TICK);
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN, 1);
return;
}
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tcp_make_syn (tc, b);
/* Measure RTT with this */
tc->rtt_ts = tcp_time_now_us (vlib_num_workers ()? 1 : 0);
tc->rtt_seq = tc->snd_nxt;
tc->rto_boff = 0;
tcp_push_ip_hdr (wrk, tc, b);
tcp_enqueue_to_ip_lookup (wrk, b, bi, tc->c_is_ip4, tc->c_fib_index);
TCP_EVT (TCP_EVT_SYN_SENT, tc);
}
void
tcp_send_synack (tcp_connection_t * tc)
{
tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi;
tcp_retransmit_timer_force_update (tc);
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT, 1);
return;
}
tc->rtt_ts = tcp_time_now_us (tc->c_thread_index);
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tcp_make_synack (tc, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
TCP_EVT (TCP_EVT_SYNACK_SENT, tc);
}
/**
* Flush tx frame populated by retransmits and timer pops
*/
void
tcp_flush_frame_to_output (tcp_worker_ctx_t * wrk, u8 is_ip4)
{
if (wrk->tx_frames[!is_ip4])
{
u32 next_index;
next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
vlib_put_frame_to_node (wrk->vm, next_index, wrk->tx_frames[!is_ip4]);
wrk->tx_frames[!is_ip4] = 0;
}
}
/**
* Flush ip lookup tx frames populated by timer pops
*/
static void
tcp_flush_frame_to_ip_lookup (tcp_worker_ctx_t * wrk, u8 is_ip4)
{
if (wrk->ip_lookup_tx_frames[!is_ip4])
{
u32 next_index;
next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
vlib_put_frame_to_node (wrk->vm, next_index,
wrk->ip_lookup_tx_frames[!is_ip4]);
wrk->ip_lookup_tx_frames[!is_ip4] = 0;
}
}
/**
* Flush v4 and v6 tcp and ip-lookup tx frames for thread index
*/
void
tcp_flush_frames_to_output (tcp_worker_ctx_t * wrk)
{
tcp_flush_frame_to_output (wrk, 1);
tcp_flush_frame_to_output (wrk, 0);
tcp_flush_frame_to_ip_lookup (wrk, 1);
tcp_flush_frame_to_ip_lookup (wrk, 0);
}
/**
* Send FIN
*/
void
tcp_send_fin (tcp_connection_t * tc)
{
tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi;
u8 fin_snt = 0;
fin_snt = tc->flags & TCP_CONN_FINSNT;
if (fin_snt)
tc->snd_nxt -= 1;
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
/* Out of buffers so program fin retransmit ASAP */
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT, 1);
if (fin_snt)
tc->snd_nxt += 1;
else
/* Make sure retransmit retries a fin not data */
tc->flags |= TCP_CONN_FINSNT;
return;
}
/* If we have non-dupacks programmed, no need to send them */
if ((tc->flags & TCP_CONN_SNDACK) && !tc->pending_dupacks)
tc->flags &= ~TCP_CONN_SNDACK;
tcp_retransmit_timer_force_update (tc);
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tcp_make_fin (tc, b);
tcp_enqueue_to_output_now (wrk, b, bi, tc->c_is_ip4);
TCP_EVT (TCP_EVT_FIN_SENT, tc);
/* Account for the FIN */
tc->snd_nxt += 1;
if (!fin_snt)
{
tc->flags |= TCP_CONN_FINSNT;
tc->flags &= ~TCP_CONN_FINPNDG;
tc->snd_una_max = seq_max (tc->snd_una_max, tc->snd_nxt);
}
}
/**
* Push TCP header and update connection variables. Should only be called
* for segments with data, not for 'control' packets.
*/
always_inline void
tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b, u32 snd_nxt,
u8 compute_opts, u8 maybe_burst, u8 update_snd_nxt)
{
u8 tcp_hdr_opts_len, flags = TCP_FLAG_ACK;
u32 advertise_wnd, data_len;
tcp_main_t *tm = &tcp_main;
tcp_header_t *th;
data_len = b->current_length;
if (PREDICT_FALSE (b->flags & VLIB_BUFFER_NEXT_PRESENT))
data_len += b->total_length_not_including_first_buffer;
vnet_buffer (b)->tcp.flags = 0;
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
if (compute_opts)
tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
if (maybe_burst)
advertise_wnd = tc->rcv_wnd >> tc->rcv_wscale;
else
advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
if (PREDICT_FALSE (tc->flags & TCP_CONN_PSH_PENDING))
{
if (seq_geq (tc->psh_seq, snd_nxt)
&& seq_lt (tc->psh_seq, snd_nxt + data_len))
flags |= TCP_FLAG_PSH;
}
th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, snd_nxt,
tc->rcv_nxt, tcp_hdr_opts_len, flags,
advertise_wnd);
if (maybe_burst)
{
clib_memcpy_fast ((u8 *) (th + 1),
tm->wrk_ctx[tc->c_thread_index].cached_opts,
tc->snd_opts_len);
}
else
{
u8 len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
ASSERT (len == tc->snd_opts_len);
}
/*
* Update connection variables
*/
if (update_snd_nxt)
tc->snd_nxt += data_len;
tc->rcv_las = tc->rcv_nxt;
tc->bytes_out += data_len;
tc->data_segs_out += 1;
th->checksum = tcp_compute_checksum (tc, b);
TCP_EVT (TCP_EVT_PKTIZE, tc);
}
u32
tcp_session_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
{
tcp_connection_t *tc = (tcp_connection_t *) tconn;
if (tc->flags & TCP_CONN_TRACK_BURST)
{
tcp_bt_check_app_limited (tc);
tcp_bt_track_tx (tc);
tc->flags &= ~TCP_CONN_TRACK_BURST;
}
tcp_push_hdr_i (tc, b, tc->snd_nxt, /* compute opts */ 0, /* burst */ 1,
/* update_snd_nxt */ 1);
tc->snd_una_max = seq_max (tc->snd_nxt, tc->snd_una_max);
tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
/* If not tracking an ACK, start tracking */
if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
{
tc->rtt_ts = tcp_time_now_us (tc->c_thread_index);
tc->rtt_seq = tc->snd_nxt;
}
if (PREDICT_FALSE (!tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)))
{
tcp_retransmit_timer_set (tc);
tc->rto_boff = 0;
}
tcp_trajectory_add_start (b, 3);
return 0;
}
void
tcp_send_ack (tcp_connection_t * tc)
{
tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi;
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
tcp_update_rcv_wnd (tc);
return;
}
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tcp_make_ack (tc, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
}
void
tcp_program_ack (tcp_connection_t * tc)
{
if (!(tc->flags & TCP_CONN_SNDACK))
{
session_add_self_custom_tx_evt (&tc->connection, 1);
tc->flags |= TCP_CONN_SNDACK;
}
}
void
tcp_program_dupack (tcp_connection_t * tc)
{
if (!(tc->flags & TCP_CONN_SNDACK))
{
session_add_self_custom_tx_evt (&tc->connection, 1);
tc->flags |= TCP_CONN_SNDACK;
}
if (tc->pending_dupacks < 255)
tc->pending_dupacks += 1;
}
void
tcp_program_retransmit (tcp_connection_t * tc)
{
if (!(tc->flags & TCP_CONN_RXT_PENDING))
{
session_add_self_custom_tx_evt (&tc->connection, 0);
tc->flags |= TCP_CONN_RXT_PENDING;
}
}
/**
* Delayed ack timer handler
*
* Sends delayed ACK when timer expires
*/
void
tcp_timer_delack_handler (u32 index)
{
u32 thread_index = vlib_get_thread_index ();
tcp_connection_t *tc;
tc = tcp_connection_get (index, thread_index);
tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
tcp_send_ack (tc);
}
/**
* Send window update ack
*
* Ensures that it will be sent only once, after a zero rwnd has been
* advertised in a previous ack, and only if rwnd has grown beyond a
* configurable value.
*/
void
tcp_send_window_update_ack (tcp_connection_t * tc)
{
if (tcp_zero_rwnd_sent (tc))
{
tcp_update_rcv_wnd (tc);
if (tc->rcv_wnd >= tcp_cfg.rwnd_min_update_ack * tc->snd_mss)
{
tcp_zero_rwnd_sent_off (tc);
tcp_program_ack (tc);
}
}
}
/**
* Allocate a new buffer and build a new tcp segment
*
* @param wrk tcp worker
* @param tc connection for which the segment will be allocated
* @param offset offset of the first byte in the tx fifo
* @param max_deq_byte segment size
* @param[out] b pointer to buffer allocated
*
* @return the number of bytes in the segment or 0 if buffer cannot be
* allocated or no data available
*/
static int
tcp_prepare_segment (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
u32 offset, u32 max_deq_bytes, vlib_buffer_t ** b)
{
u32 bytes_per_buffer = vnet_get_tcp_main ()->bytes_per_buffer;
vlib_main_t *vm = wrk->vm;
u32 bi, seg_size;
int n_bytes = 0;
u8 *data;
seg_size = max_deq_bytes + TRANSPORT_MAX_HDRS_LEN;
/*
* Prepare options
*/
tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
/*
* Allocate and fill in buffer(s)
*/
/* Easy case, buffer size greater than mss */
if (PREDICT_TRUE (seg_size <= bytes_per_buffer))
{
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
return 0;
*b = vlib_get_buffer (vm, bi);
data = tcp_init_buffer (vm, *b);
n_bytes = session_tx_fifo_peek_bytes (&tc->connection, data, offset,
max_deq_bytes);
ASSERT (n_bytes == max_deq_bytes);
b[0]->current_length = n_bytes;
tcp_push_hdr_i (tc, *b, tc->snd_una + offset, /* compute opts */ 0,
/* burst */ 0, /* update_snd_nxt */ 0);
}
/* Split mss into multiple buffers */
else
{
u32 chain_bi = ~0, n_bufs_per_seg, n_bufs;
u16 n_peeked, len_to_deq;
vlib_buffer_t *chain_b, *prev_b;
int i;
/* Make sure we have enough buffers */
n_bufs_per_seg = ceil ((double) seg_size / bytes_per_buffer);
vec_validate_aligned (wrk->tx_buffers, n_bufs_per_seg - 1,
CLIB_CACHE_LINE_BYTES);
n_bufs = vlib_buffer_alloc (vm, wrk->tx_buffers, n_bufs_per_seg);
if (PREDICT_FALSE (n_bufs != n_bufs_per_seg))
{
if (n_bufs)
vlib_buffer_free (vm, wrk->tx_buffers, n_bufs);
return 0;
}
*b = vlib_get_buffer (vm, wrk->tx_buffers[--n_bufs]);
data = tcp_init_buffer (vm, *b);
n_bytes = session_tx_fifo_peek_bytes (&tc->connection, data, offset,
bytes_per_buffer -
TRANSPORT_MAX_HDRS_LEN);
b[0]->current_length = n_bytes;
b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
b[0]->total_length_not_including_first_buffer = 0;
max_deq_bytes -= n_bytes;
chain_b = *b;
for (i = 1; i < n_bufs_per_seg; i++)
{
prev_b = chain_b;
len_to_deq = clib_min (max_deq_bytes, bytes_per_buffer);
chain_bi = wrk->tx_buffers[--n_bufs];
chain_b = vlib_get_buffer (vm, chain_bi);
chain_b->current_data = 0;
data = vlib_buffer_get_current (chain_b);
n_peeked = session_tx_fifo_peek_bytes (&tc->connection, data,
offset + n_bytes,
len_to_deq);
ASSERT (n_peeked == len_to_deq);
n_bytes += n_peeked;
chain_b->current_length = n_peeked;
chain_b->next_buffer = 0;
/* update previous buffer */
prev_b->next_buffer = chain_bi;
prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
max_deq_bytes -= n_peeked;
b[0]->total_length_not_including_first_buffer += n_peeked;
}
tcp_push_hdr_i (tc, *b, tc->snd_una + offset, /* compute opts */ 0,
/* burst */ 0, /* update_snd_nxt */ 0);
if (PREDICT_FALSE (n_bufs))
{
clib_warning ("not all buffers consumed");
vlib_buffer_free (vm, wrk->tx_buffers, n_bufs);
}
}
ASSERT (n_bytes > 0);
ASSERT (((*b)->current_data + (*b)->current_length) <= bytes_per_buffer);
return n_bytes;
}
/**
* Build a retransmit segment
*
* @return the number of bytes in the segment or 0 if there's nothing to
* retransmit
*/
static u32
tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
tcp_connection_t * tc, u32 offset,
u32 max_deq_bytes, vlib_buffer_t ** b)
{
u32 start, available_bytes;
int n_bytes = 0;
ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
ASSERT (max_deq_bytes != 0);
/*
* Make sure we can retransmit something
*/
available_bytes = transport_max_tx_dequeue (&tc->connection);
ASSERT (available_bytes >= offset);
available_bytes -= offset;
if (!available_bytes)
return 0;
max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
start = tc->snd_una + offset;
n_bytes = tcp_prepare_segment (wrk, tc, offset, max_deq_bytes, b);
if (!n_bytes)
return 0;
tc->snd_rxt_bytes += n_bytes;
if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
tcp_bt_track_rxt (tc, start, start + n_bytes);
tc->bytes_retrans += n_bytes;
tc->segs_retrans += 1;
TCP_EVT (TCP_EVT_CC_RTX, tc, offset, n_bytes);
return n_bytes;
}
static void
tcp_check_sack_reneging (tcp_connection_t * tc)
{
sack_scoreboard_t *sb = &tc->sack_sb;
sack_scoreboard_hole_t *hole;
hole = scoreboard_first_hole (sb);
if (!sb->is_reneging && (!hole || hole->start == tc->snd_una))
return;
scoreboard_clear_reneging (sb, tc->snd_una, tc->snd_nxt);
}
/**
* Reset congestion control, switch cwnd to loss window and try again.
*/
static void
tcp_cc_init_rxt_timeout (tcp_connection_t * tc)
{
TCP_EVT (TCP_EVT_CC_EVT, tc, 6);
tc->prev_ssthresh = tc->ssthresh;
tc->prev_cwnd = tc->cwnd;
/* If we entrered loss without fast recovery, notify cc algo of the
* congestion event such that it can update ssthresh and its state */
if (!tcp_in_fastrecovery (tc))
tcp_cc_congestion (tc);
/* Let cc algo decide loss cwnd and ssthresh post unrecovered loss */
tcp_cc_loss (tc);
tc->rtt_ts = 0;
tc->cwnd_acc_bytes = 0;
tc->tr_occurences += 1;
tcp_recovery_on (tc);
}
void
tcp_timer_retransmit_handler (u32 tc_index)
{
u32 thread_index = vlib_get_thread_index ();
tcp_worker_ctx_t *wrk = tcp_get_worker (thread_index);
vlib_main_t *vm = wrk->vm;
tcp_connection_t *tc;
vlib_buffer_t *b = 0;
u32 bi, n_bytes;
tc = tcp_connection_get (tc_index, thread_index);
/* Note: the connection may have been closed and pool_put */
if (PREDICT_FALSE (tc == 0 || tc->state == TCP_STATE_SYN_SENT))
return;
tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
/* Wait-close and retransmit could pop at the same time */
if (tc->state == TCP_STATE_CLOSED)
return;
if (tc->state >= TCP_STATE_ESTABLISHED)
{
TCP_EVT (TCP_EVT_CC_EVT, tc, 2);
/* Lost FIN, retransmit and return */
if (tc->flags & TCP_CONN_FINSNT)
{
tcp_send_fin (tc);
tc->rto_boff += 1;
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
return;
}
/* Shouldn't be here. This condition is tricky because it has to take
* into account boff > 0 due to persist timeout. */
if ((tc->rto_boff == 0 && tc->snd_una == tc->snd_nxt)
|| (tc->rto_boff > 0 && seq_geq (tc->snd_una, tc->snd_congestion)
&& !tcp_flight_size (tc)))
{
ASSERT (!tcp_in_recovery (tc));
tc->rto_boff = 0;
return;
}
/* We're not in recovery so make sure rto_boff is 0. Can be non 0 due
* to persist timer timeout */
if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
{
tc->rto_boff = 0;
tcp_update_rto (tc);
}
/* Peer is dead or network connectivity is lost. Close connection.
* RFC 1122 section 4.2.3.5 recommends a value of at least 100s. For
* a min rto of 0.2s we need to retry about 8 times. */
if (tc->rto_boff >= TCP_RTO_BOFF_MAX)
{
tcp_send_reset (tc);
tcp_connection_set_state (tc, TCP_STATE_CLOSED);
session_transport_closing_notify (&tc->connection);
tcp_connection_timers_reset (tc);
tcp_timer_update (tc, TCP_TIMER_WAITCLOSE, tcp_cfg.closewait_time);
return;
}
if (tcp_opts_sack_permitted (&tc->rcv_opts))
tcp_check_sack_reneging (tc);
/* Update send congestion to make sure that rxt has data to send */
tc->snd_congestion = tc->snd_nxt;
/* Send the first unacked segment. If we're short on buffers, return
* as soon as possible */
n_bytes = tcp_prepare_retransmit_segment (wrk, tc, 0, tc->snd_mss, &b);
if (!n_bytes)
{
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT, 1);
return;
}
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
tcp_retransmit_timer_force_update (tc);
tc->rto_boff += 1;
if (tc->rto_boff == 1)
{
tcp_cc_init_rxt_timeout (tc);
/* Record timestamp. Eifel detection algorithm RFC3522 */
tc->snd_rxt_ts = tcp_tstamp (tc);
}
if (tcp_opts_sack_permitted (&tc->rcv_opts))
scoreboard_init_rxt (&tc->sack_sb, tc->snd_una + n_bytes);
tcp_program_retransmit (tc);
}
/* Retransmit SYN-ACK */
else if (tc->state == TCP_STATE_SYN_RCVD)
{
TCP_EVT (TCP_EVT_CC_EVT, tc, 2);
tc->rtt_ts = 0;
/* Passive open establish timeout */
if (tc->rto > TCP_ESTABLISH_TIME >> 1)
{
tcp_connection_set_state (tc, TCP_STATE_CLOSED);
tcp_connection_timers_reset (tc);
tcp_timer_update (tc, TCP_TIMER_WAITCLOSE, tcp_cfg.cleanup_time);
return;
}
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT, 1);
return;
}
tc->rto_boff += 1;
if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
tcp_retransmit_timer_force_update (tc);
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tcp_make_synack (tc, b);
TCP_EVT (TCP_EVT_SYN_RXT, tc, 1);
/* Retransmit timer already updated, just enqueue to output */
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
}
else
{
ASSERT (tc->state == TCP_STATE_CLOSED);
return;
}
}
/**
* SYN retransmit timer handler. Active open only.
*/
void
tcp_timer_retransmit_syn_handler (u32 tc_index)
{
u32 thread_index = vlib_get_thread_index ();
tcp_worker_ctx_t *wrk = tcp_get_worker (thread_index);
vlib_main_t *vm = wrk->vm;
tcp_connection_t *tc;
vlib_buffer_t *b = 0;
u32 bi;
tc = tcp_half_open_connection_get (tc_index);
/* Note: the connection may have transitioned to ESTABLISHED... */
if (PREDICT_FALSE (tc == 0 || tc->state != TCP_STATE_SYN_SENT))
return;
tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
/* Half-open connection actually moved to established but we were
* waiting for syn retransmit to pop to call cleanup from the right
* thread. */
if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
{
if (tcp_half_open_connection_cleanup (tc))
TCP_DBG ("could not remove half-open connection");
return;
}
TCP_EVT (TCP_EVT_CC_EVT, tc, 2);
tc->rtt_ts = 0;
/* Active open establish timeout */
if (tc->rto >= TCP_ESTABLISH_TIME >> 1)
{
session_stream_connect_notify (&tc->connection, 1 /* fail */ );
tcp_connection_cleanup (tc);
return;
}
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN, 1);
return;
}
/* Try without increasing RTO a number of times. If this fails,
* start growing RTO exponentially */
tc->rto_boff += 1;
if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
b = vlib_get_buffer (vm, bi);
tcp_init_buffer (vm, b);
tcp_make_syn (tc, b);
TCP_EVT (TCP_EVT_SYN_RXT, tc, 0);
/* This goes straight to ipx_lookup */
tcp_push_ip_hdr (wrk, tc, b);
tcp_enqueue_to_ip_lookup (wrk, b, bi, tc->c_is_ip4, tc->c_fib_index);
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
tc->rto * TCP_TO_TIMER_TICK);
}
/**
* Got 0 snd_wnd from peer, try to do something about it.
*
*/
void
tcp_timer_persist_handler (u32 index)
{
u32 thread_index = vlib_get_thread_index ();
tcp_worker_ctx_t *wrk = tcp_get_worker (thread_index);
u32 bi, max_snd_bytes, available_bytes, offset;
tcp_main_t *tm = vnet_get_tcp_main ();
vlib_main_t *vm = wrk->vm;
tcp_connection_t *tc;
vlib_buffer_t *b;
int n_bytes = 0;
u8 *data;
tc = tcp_connection_get_if_valid (index, thread_index);
if (!tc)
return;
/* Make sure timer handle is set to invalid */
tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
/* Problem already solved or worse */
if (tc->state == TCP_STATE_CLOSED || tc->snd_wnd > tc->snd_mss
|| (tc->flags & TCP_CONN_FINSNT))
return;
available_bytes = transport_max_tx_dequeue (&tc->connection);
offset = tc->snd_nxt - tc->snd_una;
/* Reprogram persist if no new bytes available to send. We may have data
* next time */
if (!available_bytes)
{
tcp_persist_timer_set (tc);
return;
}
if (available_bytes <= offset)
{
ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
return;
}
/* Increment RTO backoff */
tc->rto_boff += 1;
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
/*
* Try to force the first unsent segment (or buffer)
*/
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
tcp_persist_timer_set (tc);
return;
}
b = vlib_get_buffer (vm, bi);
data = tcp_init_buffer (vm, b);
tcp_validate_txf_size (tc, offset);
tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
max_snd_bytes = clib_min (tc->snd_mss,
tm->bytes_per_buffer - TRANSPORT_MAX_HDRS_LEN);
n_bytes = session_tx_fifo_peek_bytes (&tc->connection, data, offset,
max_snd_bytes);
b->current_length = n_bytes;
ASSERT (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)
|| tc->snd_nxt == tc->snd_una_max
|| tc->rto_boff > 1));
if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
{
tcp_bt_check_app_limited (tc);
tcp_bt_track_tx (tc);
}
tcp_push_hdr_i (tc, b, tc->snd_nxt, /* compute opts */ 0,
/* burst */ 0, /* update_snd_nxt */ 1);
tc->snd_una_max = seq_max (tc->snd_nxt, tc->snd_una_max);
tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
/* Just sent new data, enable retransmit */
tcp_retransmit_timer_update (tc);
}
/**
* Retransmit first unacked segment
*/
int
tcp_retransmit_first_unacked (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
{
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
u32 bi, n_bytes;
TCP_EVT (TCP_EVT_CC_EVT, tc, 1);
n_bytes = tcp_prepare_retransmit_segment (wrk, tc, 0, tc->snd_mss, &b);
if (!n_bytes)
return -1;
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
return 0;
}
static int
tcp_transmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
u32 burst_size)
{
u32 offset, n_segs = 0, n_written, bi, available_wnd;
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b = 0;
offset = tc->snd_nxt - tc->snd_una;
available_wnd = tc->snd_wnd - offset;
burst_size = clib_min (burst_size, available_wnd / tc->snd_mss);
while (n_segs < burst_size)
{
n_written = tcp_prepare_segment (wrk, tc, offset, tc->snd_mss, &b);
if (!n_written)
goto done;
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
offset += n_written;
n_segs += 1;
tc->snd_nxt += n_written;
tc->snd_una_max = seq_max (tc->snd_nxt, tc->snd_una_max);
}
done:
return n_segs;
}
/**
* Estimate send space using proportional rate reduction (RFC6937)
*/
int
tcp_fastrecovery_prr_snd_space (tcp_connection_t * tc)
{
u32 pipe, prr_out;
int space;
pipe = tcp_flight_size (tc);
prr_out = tc->snd_rxt_bytes + (tc->snd_nxt - tc->snd_congestion);
if (pipe > tc->ssthresh)
{
space = ((int) tc->prr_delivered * ((f64) tc->ssthresh / tc->prev_cwnd))
- prr_out;
}
else
{
int limit;
limit = clib_max ((int) (tc->prr_delivered - prr_out), 0) + tc->snd_mss;
space = clib_min (tc->ssthresh - pipe, limit);
}
space = clib_max (space, prr_out ? 0 : tc->snd_mss);
return space;
}
static inline u8
tcp_retransmit_should_retry_head (tcp_connection_t * tc,
sack_scoreboard_t * sb)
{
u32 tx_adv_sack = sb->high_sacked - tc->snd_congestion;
f64 rr = (f64) tc->ssthresh / tc->prev_cwnd;
return (tx_adv_sack > (tc->snd_una - tc->prr_start) * rr);
}
static inline u8
tcp_max_tx_deq (tcp_connection_t * tc)
{
return (transport_max_tx_dequeue (&tc->connection)
- (tc->snd_nxt - tc->snd_una));
}
#define scoreboard_rescue_rxt_valid(_sb, _tc) \
(seq_geq (_sb->rescue_rxt, _tc->snd_una) \
&& seq_leq (_sb->rescue_rxt, _tc->snd_congestion))
/**
* Do retransmit with SACKs
*/
static int
tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
u32 burst_size)
{
u8 snd_limited = 0, can_rescue = 0, reset_pacer = 0;
u32 n_written = 0, offset, max_bytes, n_segs = 0;
u32 bi, max_deq, burst_bytes, sent_bytes;
sack_scoreboard_hole_t *hole;
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b = 0;
sack_scoreboard_t *sb;
int snd_space;
u64 time_now;
ASSERT (tcp_in_cong_recovery (tc));
time_now = wrk->vm->clib_time.last_cpu_time;
burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
time_now);
burst_size = clib_min (burst_size, burst_bytes / tc->snd_mss);
if (!burst_size)
{
tcp_program_retransmit (tc);
return 0;
}
if (tcp_in_recovery (tc))
snd_space = tcp_available_cc_snd_space (tc);
else
snd_space = tcp_fastrecovery_prr_snd_space (tc);
if (snd_space < tc->snd_mss)
{
reset_pacer = burst_bytes > tc->snd_mss;
goto done;
}
reset_pacer = snd_space < burst_bytes;
sb = &tc->sack_sb;
/* Check if snd_una is a lost retransmit */
if (pool_elts (sb->holes)
&& seq_gt (sb->high_sacked, tc->snd_congestion)
&& tc->rxt_head != tc->snd_una
&& tcp_retransmit_should_retry_head (tc, sb))
{
n_written = tcp_prepare_retransmit_segment (wrk, tc, 0, tc->snd_mss,
&b);
if (!n_written)
{
tcp_program_retransmit (tc);
goto done;
}
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
n_segs = 1;
tc->rxt_head = tc->snd_una;
tc->rxt_delivered += n_written;
tc->prr_delivered += n_written;
ASSERT (tc->rxt_delivered <= tc->snd_rxt_bytes);
}
TCP_EVT (TCP_EVT_CC_EVT, tc, 0);
hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
max_deq = transport_max_tx_dequeue (&tc->connection);
max_deq -= tc->snd_nxt - tc->snd_una;
while (snd_space > 0 && n_segs < burst_size)
{
hole = scoreboard_next_rxt_hole (sb, hole, max_deq, &can_rescue,
&snd_limited);
if (!hole)
{
/* We are out of lost holes to retransmit so send some new data. */
if (max_deq > tc->snd_mss)
{
u32 n_segs_new;
int av_wnd;
av_wnd = (int) tc->snd_wnd - (tc->snd_nxt - tc->snd_una);
av_wnd = clib_max (av_wnd, 0);
snd_space = clib_min (snd_space, av_wnd);
snd_space = clib_min (max_deq, snd_space);
burst_size = clib_min (burst_size - n_segs,
snd_space / tc->snd_mss);
burst_size = clib_min (burst_size, TCP_RXT_MAX_BURST);
n_segs_new = tcp_transmit_unsent (wrk, tc, burst_size);
if (max_deq > n_segs_new * tc->snd_mss)
tcp_program_retransmit (tc);
n_segs += n_segs_new;
goto done;
}
if (tcp_in_recovery (tc) || !can_rescue
|| scoreboard_rescue_rxt_valid (sb, tc))
break;
/* If rescue rxt undefined or less than snd_una then one segment of
* up to SMSS octets that MUST include the highest outstanding
* unSACKed sequence number SHOULD be returned, and RescueRxt set to
* RecoveryPoint. HighRxt MUST NOT be updated.
*/
max_bytes = clib_min (tc->snd_mss,
tc->snd_congestion - tc->snd_una);
max_bytes = clib_min (max_bytes, snd_space);
offset = tc->snd_congestion - tc->snd_una - max_bytes;
sb->rescue_rxt = tc->snd_congestion;
n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
max_bytes, &b);
if (!n_written)
goto done;
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
n_segs += 1;
break;
}
max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
if (max_bytes == 0)
break;
offset = sb->high_rxt - tc->snd_una;
n_written = tcp_prepare_retransmit_segment (wrk, tc, offset, max_bytes,
&b);
ASSERT (n_written <= snd_space);
/* Nothing left to retransmit */
if (n_written == 0)
break;
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
sb->high_rxt += n_written;
snd_space -= n_written;
n_segs += 1;
}
if (hole)
tcp_program_retransmit (tc);
done:
if (reset_pacer)
{
transport_connection_tx_pacer_reset_bucket (&tc->connection,
vm->clib_time.
last_cpu_time);
}
else
{
sent_bytes = clib_min (n_segs * tc->snd_mss, burst_bytes);
transport_connection_tx_pacer_update_bytes (&tc->connection,
sent_bytes);
}
return n_segs;
}
/**
* Fast retransmit without SACK info
*/
static int
tcp_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
u32 burst_size)
{
u32 n_written = 0, offset = 0, bi, max_deq, n_segs_now;
u32 burst_bytes, sent_bytes;
vlib_main_t *vm = wrk->vm;
int snd_space, n_segs = 0;
u8 cc_limited = 0;
vlib_buffer_t *b;
u64 time_now;
ASSERT (tcp_in_fastrecovery (tc));
TCP_EVT (TCP_EVT_CC_EVT, tc, 0);
time_now = wrk->vm->clib_time.last_cpu_time;
burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
time_now);
burst_size = clib_min (burst_size, burst_bytes / tc->snd_mss);
if (!burst_size)
{
tcp_program_retransmit (tc);
return 0;
}
snd_space = tcp_available_cc_snd_space (tc);
cc_limited = snd_space < burst_bytes;
if (!tcp_fastrecovery_first (tc))
goto send_unsent;
/* RFC 6582: [If a partial ack], retransmit the first unacknowledged
* segment. */
while (snd_space > 0 && n_segs < burst_size)
{
n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
tc->snd_mss, &b);
/* Nothing left to retransmit */
if (n_written == 0)
break;
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
snd_space -= n_written;
offset += n_written;
n_segs += 1;
}
if (n_segs == burst_size)
goto done;
send_unsent:
/* RFC 6582: Send a new segment if permitted by the new value of cwnd. */
if (snd_space < tc->snd_mss || tc->snd_mss == 0)
goto done;
max_deq = transport_max_tx_dequeue (&tc->connection);
max_deq -= tc->snd_nxt - tc->snd_una;
if (max_deq)
{
snd_space = clib_min (max_deq, snd_space);
burst_size = clib_min (burst_size - n_segs, snd_space / tc->snd_mss);
n_segs_now = tcp_transmit_unsent (wrk, tc, burst_size);
if (max_deq > n_segs_now * tc->snd_mss)
tcp_program_retransmit (tc);
n_segs += n_segs_now;
}
done:
tcp_fastrecovery_first_off (tc);
sent_bytes = clib_min (n_segs * tc->snd_mss, burst_bytes);
sent_bytes = cc_limited ? burst_bytes : sent_bytes;
transport_connection_tx_pacer_update_bytes (&tc->connection, sent_bytes);
return n_segs;
}
static int
tcp_send_acks (tcp_connection_t * tc, u32 max_burst_size)
{
int j, n_acks;
if (!tc->pending_dupacks)
{
if (tcp_in_cong_recovery (tc) || !tcp_max_tx_deq (tc)
|| tc->state != TCP_STATE_ESTABLISHED)
{
tcp_send_ack (tc);
return 1;
}
return 0;
}
/* If we're supposed to send dupacks but have no ooo data
* send only one ack */
if (!vec_len (tc->snd_sacks))
{
tcp_send_ack (tc);
tc->pending_dupacks = 0;
return 1;
}
/* Start with first sack block */
tc->snd_sack_pos = 0;
/* Generate enough dupacks to cover all sack blocks. Do not generate
* more sacks than the number of packets received. But do generate at
* least 3, i.e., the number needed to signal congestion, if needed. */
n_acks = vec_len (tc->snd_sacks) / TCP_OPTS_MAX_SACK_BLOCKS;
n_acks = clib_min (n_acks, tc->pending_dupacks);
n_acks = clib_max (n_acks, clib_min (tc->pending_dupacks, 3));
for (j = 0; j < clib_min (n_acks, max_burst_size); j++)
tcp_send_ack (tc);
if (n_acks < max_burst_size)
{
tc->pending_dupacks = 0;
tc->snd_sack_pos = 0;
tc->dupacks_out += n_acks;
return n_acks;
}
else
{
TCP_DBG ("constrained by burst size");
tc->pending_dupacks = n_acks - max_burst_size;
tc->dupacks_out += max_burst_size;
tcp_program_dupack (tc);
return max_burst_size;
}
}
static int
tcp_do_retransmit (tcp_connection_t * tc, u32 max_burst_size)
{
tcp_worker_ctx_t *wrk;
u32 n_segs;
wrk = tcp_get_worker (tc->c_thread_index);
if (tcp_opts_sack_permitted (&tc->rcv_opts))
n_segs = tcp_retransmit_sack (wrk, tc, max_burst_size);
else
n_segs = tcp_retransmit_no_sack (wrk, tc, max_burst_size);
return n_segs;
}
int
tcp_session_custom_tx (void *conn, u32 max_burst_size)
{
tcp_connection_t *tc = (tcp_connection_t *) conn;
u32 n_segs = 0;
if (tcp_in_cong_recovery (tc) && (tc->flags & TCP_CONN_RXT_PENDING))
{
tc->flags &= ~TCP_CONN_RXT_PENDING;
n_segs = tcp_do_retransmit (tc, max_burst_size);
max_burst_size -= n_segs;
}
if (!(tc->flags & TCP_CONN_SNDACK))
return n_segs;
tc->flags &= ~TCP_CONN_SNDACK;
/* We have retransmitted packets and no dupack */
if (n_segs && !tc->pending_dupacks)
return n_segs;
if (!max_burst_size)
{
tcp_program_ack (tc);
return max_burst_size;
}
n_segs += tcp_send_acks (tc, max_burst_size);
return n_segs;
}
#endif /* CLIB_MARCH_VARIANT */
static void
tcp_output_handle_link_local (tcp_connection_t * tc0, vlib_buffer_t * b0,
u16 * next0, u32 * error0)
{
ip_adjacency_t *adj;
adj_index_t ai;
/* Not thread safe but as long as the connection exists the adj should
* not be removed */
ai = adj_nbr_find (FIB_PROTOCOL_IP6, VNET_LINK_IP6, &tc0->c_rmt_ip,
tc0->sw_if_index);
if (ai == ADJ_INDEX_INVALID)
{
vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
*next0 = TCP_OUTPUT_NEXT_DROP;
*error0 = TCP_ERROR_LINK_LOCAL_RW;
return;
}
adj = adj_get (ai);
if (PREDICT_TRUE (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE))
*next0 = TCP_OUTPUT_NEXT_IP_REWRITE;
else if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP)
*next0 = TCP_OUTPUT_NEXT_IP_ARP;
else
{
*next0 = TCP_OUTPUT_NEXT_DROP;
*error0 = TCP_ERROR_LINK_LOCAL_RW;
}
vnet_buffer (b0)->ip.adj_index[VLIB_TX] = ai;
}
static void
tcp46_output_trace_frame (vlib_main_t * vm, vlib_node_runtime_t * node,
u32 * to_next, u32 n_bufs)
{
u32 n_trace = vlib_get_trace_count (vm, node);
tcp_connection_t *tc;
tcp_tx_trace_t *t;
vlib_buffer_t *b;
tcp_header_t *th;
int i;
for (i = 0; i < clib_min (n_trace, n_bufs); i++)
{
b = vlib_get_buffer (vm, to_next[i]);
th = vlib_buffer_get_current (b);
tc = tcp_connection_get (vnet_buffer (b)->tcp.connection_index,
vm->thread_index);
t = vlib_add_trace (vm, node, b, sizeof (*t));
clib_memcpy_fast (&t->tcp_header, th, sizeof (t->tcp_header));
clib_memcpy_fast (&t->tcp_connection, tc, sizeof (t->tcp_connection));
}
}
always_inline void
tcp_output_push_ip (vlib_main_t * vm, vlib_buffer_t * b0,
tcp_connection_t * tc0, u8 is_ip4)
{
u8 __clib_unused *ih0;
tcp_header_t __clib_unused *th0 = vlib_buffer_get_current (b0);
TCP_EVT (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
if (is_ip4)
ih0 = vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
IP_PROTOCOL_TCP, tcp_csum_offload (tc0));
else
ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6, &tc0->c_rmt_ip6,
IP_PROTOCOL_TCP);
}
always_inline void
tcp_check_if_gso (tcp_connection_t * tc, vlib_buffer_t * b)
{
if (PREDICT_TRUE (!(tc->cfg_flags & TCP_CFG_F_TSO)))
return;
u16 data_len = b->current_length - sizeof (tcp_header_t) - tc->snd_opts_len;
if (PREDICT_FALSE (b->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID))
data_len += b->total_length_not_including_first_buffer;
if (PREDICT_TRUE (data_len <= tc->snd_mss))
return;
else
{
ASSERT ((b->flags & VNET_BUFFER_F_L3_HDR_OFFSET_VALID) != 0);
ASSERT ((b->flags & VNET_BUFFER_F_L4_HDR_OFFSET_VALID) != 0);
b->flags |= VNET_BUFFER_F_GSO;
vnet_buffer2 (b)->gso_l4_hdr_sz =
sizeof (tcp_header_t) + tc->snd_opts_len;
vnet_buffer2 (b)->gso_size = tc->snd_mss;
}
}
always_inline void
tcp_output_handle_packet (tcp_connection_t * tc0, vlib_buffer_t * b0,
vlib_node_runtime_t * error_node, u16 * next0,
u8 is_ip4)
{
/* If next_index is not drop use it */
if (tc0->next_node_index)
{
*next0 = tc0->next_node_index;
vnet_buffer (b0)->tcp.next_node_opaque = tc0->next_node_opaque;
}
else
{
*next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
}
vnet_buffer (b0)->sw_if_index[VLIB_TX] = tc0->c_fib_index;
vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
if (!is_ip4)
{
u32 error0 = 0;
if (PREDICT_FALSE (ip6_address_is_link_local_unicast (&tc0->c_rmt_ip6)))
tcp_output_handle_link_local (tc0, b0, next0, &error0);
if (PREDICT_FALSE (error0))
{
b0->error = error_node->errors[error0];
return;
}
}
if (!TCP_ALWAYS_ACK)
tcp_timer_reset (tc0, TCP_TIMER_DELACK);
tc0->segs_out += 1;
}
always_inline uword
tcp46_output_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * frame, int is_ip4)
{
u32 n_left_from, *from, thread_index = vm->thread_index;
vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
u16 nexts[VLIB_FRAME_SIZE], *next;
vlib_node_runtime_t *error_node;
error_node = vlib_node_get_runtime (vm, tcp_node_index (output, is_ip4));
from = vlib_frame_vector_args (frame);
n_left_from = frame->n_vectors;
tcp_set_time_now (tcp_get_worker (thread_index));
if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
tcp46_output_trace_frame (vm, node, from, n_left_from);
vlib_get_buffers (vm, from, bufs, n_left_from);
b = bufs;
next = nexts;
while (n_left_from >= 4)
{
tcp_connection_t *tc0, *tc1;
{
vlib_prefetch_buffer_header (b[2], STORE);
CLIB_PREFETCH (b[2]->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
vlib_prefetch_buffer_header (b[3], STORE);
CLIB_PREFETCH (b[3]->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
}
tc0 = tcp_connection_get (vnet_buffer (b[0])->tcp.connection_index,
thread_index);
tc1 = tcp_connection_get (vnet_buffer (b[1])->tcp.connection_index,
thread_index);
if (PREDICT_TRUE (!tc0 + !tc1 == 0))
{
tcp_output_push_ip (vm, b[0], tc0, is_ip4);
tcp_output_push_ip (vm, b[1], tc1, is_ip4);
tcp_check_if_gso (tc0, b[0]);
tcp_check_if_gso (tc1, b[1]);
tcp_output_handle_packet (tc0, b[0], error_node, &next[0], is_ip4);
tcp_output_handle_packet (tc1, b[1], error_node, &next[1], is_ip4);
}
else
{
if (tc0 != 0)
{
tcp_output_push_ip (vm, b[0], tc0, is_ip4);
tcp_check_if_gso (tc0, b[0]);
tcp_output_handle_packet (tc0, b[0], error_node, &next[0],
is_ip4);
}
else
{
b[0]->error = error_node->errors[TCP_ERROR_INVALID_CONNECTION];
next[0] = TCP_OUTPUT_NEXT_DROP;
}
if (tc1 != 0)
{
tcp_output_push_ip (vm, b[1], tc1, is_ip4);
tcp_check_if_gso (tc1, b[1]);
tcp_output_handle_packet (tc1, b[1], error_node, &next[1],
is_ip4);
}
else
{
b[1]->error = error_node->errors[TCP_ERROR_INVALID_CONNECTION];
next[1] = TCP_OUTPUT_NEXT_DROP;
}
}
b += 2;
next += 2;
n_left_from -= 2;
}
while (n_left_from > 0)
{
tcp_connection_t *tc0;
if (n_left_from > 1)
{
vlib_prefetch_buffer_header (b[1], STORE);
CLIB_PREFETCH (b[1]->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
}
tc0 = tcp_connection_get (vnet_buffer (b[0])->tcp.connection_index,
thread_index);
if (PREDICT_TRUE (tc0 != 0))
{
tcp_output_push_ip (vm, b[0], tc0, is_ip4);
tcp_check_if_gso (tc0, b[0]);
tcp_output_handle_packet (tc0, b[0], error_node, &next[0], is_ip4);
}
else
{
b[0]->error = error_node->errors[TCP_ERROR_INVALID_CONNECTION];
next[0] = TCP_OUTPUT_NEXT_DROP;
}
b += 1;
next += 1;
n_left_from -= 1;
}
vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
vlib_node_increment_counter (vm, tcp_node_index (output, is_ip4),
TCP_ERROR_PKTS_SENT, frame->n_vectors);
return frame->n_vectors;
}
VLIB_NODE_FN (tcp4_output_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
}
VLIB_NODE_FN (tcp6_output_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (tcp4_output_node) =
{
.name = "tcp4-output",
/* Takes a vector of packets. */
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.protocol_hint = VLIB_NODE_PROTO_HINT_TCP,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_OUTPUT_N_NEXT,
.next_nodes = {
#define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
foreach_tcp4_output_next
#undef _
},
.format_buffer = format_tcp_header,
.format_trace = format_tcp_tx_trace,
};
/* *INDENT-ON* */
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (tcp6_output_node) =
{
.name = "tcp6-output",
/* Takes a vector of packets. */
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.protocol_hint = VLIB_NODE_PROTO_HINT_TCP,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_OUTPUT_N_NEXT,
.next_nodes = {
#define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
foreach_tcp6_output_next
#undef _
},
.format_buffer = format_tcp_header,
.format_trace = format_tcp_tx_trace,
};
/* *INDENT-ON* */
typedef enum _tcp_reset_next
{
TCP_RESET_NEXT_DROP,
TCP_RESET_NEXT_IP_LOOKUP,
TCP_RESET_N_NEXT
} tcp_reset_next_t;
#define foreach_tcp4_reset_next \
_(DROP, "error-drop") \
_(IP_LOOKUP, "ip4-lookup")
#define foreach_tcp6_reset_next \
_(DROP, "error-drop") \
_(IP_LOOKUP, "ip6-lookup")
static uword
tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * from_frame, u8 is_ip4)
{
u32 n_left_from, next_index, *from, *to_next;
u32 my_thread_index = vm->thread_index;
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_tx_trace_t *t0;
tcp_header_t *th0;
u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
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);
if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
my_thread_index, is_ip4))
{
error0 = TCP_ERROR_LOOKUP_DROPS;
next0 = TCP_RESET_NEXT_DROP;
goto done;
}
/* Prepare to send to IP lookup */
vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
next0 = TCP_RESET_NEXT_IP_LOOKUP;
done:
b0->error = node->errors[error0];
b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
{
th0 = vlib_buffer_get_current (b0);
if (is_ip4)
th0 = ip4_next_header ((ip4_header_t *) th0);
else
th0 = ip6_next_header ((ip6_header_t *) th0);
t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
clib_memcpy_fast (&t0->tcp_header, th0,
sizeof (t0->tcp_header));
}
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;
}
VLIB_NODE_FN (tcp4_reset_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return tcp46_send_reset_inline (vm, node, from_frame, 1);
}
VLIB_NODE_FN (tcp6_reset_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return tcp46_send_reset_inline (vm, node, from_frame, 0);
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (tcp4_reset_node) = {
.name = "tcp4-reset",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_RESET_N_NEXT,
.next_nodes = {
#define _(s,n) [TCP_RESET_NEXT_##s] = n,
foreach_tcp4_reset_next
#undef _
},
.format_trace = format_tcp_tx_trace,
};
/* *INDENT-ON* */
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (tcp6_reset_node) = {
.name = "tcp6-reset",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_RESET_N_NEXT,
.next_nodes = {
#define _(s,n) [TCP_RESET_NEXT_##s] = n,
foreach_tcp6_reset_next
#undef _
},
.format_trace = format_tcp_tx_trace,
};
/* *INDENT-ON* */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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