2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #include <vnet/tcp/tcp.h>
17 #include <vnet/lisp-cp/packets.h>
20 vlib_node_registration_t tcp4_output_node;
21 vlib_node_registration_t tcp6_output_node;
23 typedef enum _tcp_output_next
26 TCP_OUTPUT_NEXT_IP_LOOKUP,
30 #define foreach_tcp4_output_next \
31 _ (DROP, "error-drop") \
32 _ (IP_LOOKUP, "ip4-lookup")
34 #define foreach_tcp6_output_next \
35 _ (DROP, "error-drop") \
36 _ (IP_LOOKUP, "ip6-lookup")
38 static char *tcp_error_strings[] = {
39 #define tcp_error(n,s) s,
40 #include <vnet/tcp/tcp_error.def>
46 tcp_header_t tcp_header;
47 tcp_connection_t tcp_connection;
53 format_tcp_tx_trace (u8 * s, va_list * args)
55 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
56 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
57 tcp_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *);
58 uword indent = format_get_indent (s);
60 s = format (s, "%U\n%U%U",
61 format_tcp_header, &t->tcp_header, 128,
62 format_white_space, indent,
63 format_tcp_connection, &t->tcp_connection, 1);
69 tcp_window_compute_scale (u32 available_space)
72 while (wnd_scale < TCP_MAX_WND_SCALE
73 && (available_space >> wnd_scale) > TCP_WND_MAX)
79 * Update max segment size we're able to process.
81 * The value is constrained by our interface's MTU and IP options. It is
82 * also what we advertise to our peer.
85 tcp_update_rcv_mss (tcp_connection_t * tc)
87 /* TODO find our iface MTU */
88 tc->mss = dummy_mtu - sizeof (tcp_header_t);
92 * TCP's initial window
95 tcp_initial_wnd_unscaled (tcp_connection_t * tc)
97 /* RFC 6928 recommends the value lower. However at the time our connections
98 * are initialized, fifos may not be allocated. Therefore, advertise the
99 * smallest possible unscaled window size and update once fifos are
100 * assigned to the session.
103 tcp_update_rcv_mss (tc);
104 TCP_IW_N_SEGMENTS * tc->mss;
106 return TCP_MIN_RX_FIFO_SIZE;
110 * Compute initial window and scale factor. As per RFC1323, window field in
111 * SYN and SYN-ACK segments is never scaled.
114 tcp_initial_window_to_advertise (tcp_connection_t * tc)
118 /* Initial wnd for SYN. Fifos are not allocated yet.
119 * Use some predefined value. For SYN-ACK we still want the
120 * scale to be computed in the same way */
121 max_fifo = TCP_MAX_RX_FIFO_SIZE;
123 tc->rcv_wscale = tcp_window_compute_scale (max_fifo);
124 tc->rcv_wnd = tcp_initial_wnd_unscaled (tc);
126 return clib_min (tc->rcv_wnd, TCP_WND_MAX);
130 * Compute and return window to advertise, scaled as per RFC1323
133 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
135 if (state < TCP_STATE_ESTABLISHED)
136 return tcp_initial_window_to_advertise (tc);
138 tcp_update_rcv_wnd (tc);
140 if (tc->rcv_wnd == 0)
142 tc->flags |= TCP_CONN_SENT_RCV_WND0;
146 tc->flags &= ~TCP_CONN_SENT_RCV_WND0;
149 return tc->rcv_wnd >> tc->rcv_wscale;
153 tcp_update_rcv_wnd (tcp_connection_t * tc)
156 u32 available_space, max_fifo, wnd;
159 * Figure out how much space we have available
161 available_space = stream_session_max_rx_enqueue (&tc->connection);
162 max_fifo = stream_session_rx_fifo_size (&tc->connection);
164 ASSERT (tc->rcv_opts.mss < max_fifo);
165 if (available_space < tc->rcv_opts.mss && available_space < max_fifo >> 3)
169 * Use the above and what we know about what we've previously advertised
170 * to compute the new window
172 observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las);
173 if (observed_wnd < 0)
176 /* Bad. Thou shalt not shrink */
177 if (available_space < observed_wnd)
180 TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
184 wnd = available_space;
187 /* Make sure we have a multiple of rcv_wscale */
188 if (wnd && tc->rcv_wscale)
190 wnd &= ~(1 << tc->rcv_wscale);
192 wnd = 1 << tc->rcv_wscale;
195 tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
199 * Write TCP options to segment.
202 tcp_options_write (u8 * data, tcp_options_t * opts)
205 u32 buf, seq_len = 4;
207 if (tcp_opts_mss (opts))
209 *data++ = TCP_OPTION_MSS;
210 *data++ = TCP_OPTION_LEN_MSS;
211 buf = clib_host_to_net_u16 (opts->mss);
212 clib_memcpy (data, &buf, sizeof (opts->mss));
213 data += sizeof (opts->mss);
214 opts_len += TCP_OPTION_LEN_MSS;
217 if (tcp_opts_wscale (opts))
219 *data++ = TCP_OPTION_WINDOW_SCALE;
220 *data++ = TCP_OPTION_LEN_WINDOW_SCALE;
221 *data++ = opts->wscale;
222 opts_len += TCP_OPTION_LEN_WINDOW_SCALE;
225 if (tcp_opts_sack_permitted (opts))
227 *data++ = TCP_OPTION_SACK_PERMITTED;
228 *data++ = TCP_OPTION_LEN_SACK_PERMITTED;
229 opts_len += TCP_OPTION_LEN_SACK_PERMITTED;
232 if (tcp_opts_tstamp (opts))
234 *data++ = TCP_OPTION_TIMESTAMP;
235 *data++ = TCP_OPTION_LEN_TIMESTAMP;
236 buf = clib_host_to_net_u32 (opts->tsval);
237 clib_memcpy (data, &buf, sizeof (opts->tsval));
238 data += sizeof (opts->tsval);
239 buf = clib_host_to_net_u32 (opts->tsecr);
240 clib_memcpy (data, &buf, sizeof (opts->tsecr));
241 data += sizeof (opts->tsecr);
242 opts_len += TCP_OPTION_LEN_TIMESTAMP;
245 if (tcp_opts_sack (opts))
248 u32 n_sack_blocks = clib_min (vec_len (opts->sacks),
249 TCP_OPTS_MAX_SACK_BLOCKS);
251 if (n_sack_blocks != 0)
253 *data++ = TCP_OPTION_SACK_BLOCK;
254 *data++ = 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
255 for (i = 0; i < n_sack_blocks; i++)
257 buf = clib_host_to_net_u32 (opts->sacks[i].start);
258 clib_memcpy (data, &buf, seq_len);
260 buf = clib_host_to_net_u32 (opts->sacks[i].end);
261 clib_memcpy (data, &buf, seq_len);
264 opts_len += 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
268 /* Terminate TCP options */
271 *data++ = TCP_OPTION_EOL;
272 opts_len += TCP_OPTION_LEN_EOL;
275 /* Pad with zeroes to a u32 boundary */
278 *data++ = TCP_OPTION_NOOP;
279 opts_len += TCP_OPTION_LEN_NOOP;
285 tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale)
289 opts->flags |= TCP_OPTS_FLAG_MSS;
290 opts->mss = dummy_mtu; /*XXX discover that */
291 len += TCP_OPTION_LEN_MSS;
293 opts->flags |= TCP_OPTS_FLAG_WSCALE;
294 opts->wscale = wnd_scale;
295 len += TCP_OPTION_LEN_WINDOW_SCALE;
297 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
298 opts->tsval = tcp_time_now ();
300 len += TCP_OPTION_LEN_TIMESTAMP;
304 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
305 len += TCP_OPTION_LEN_SACK_PERMITTED;
308 /* Align to needed boundary */
309 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
314 tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
318 opts->flags |= TCP_OPTS_FLAG_MSS;
320 len += TCP_OPTION_LEN_MSS;
322 if (tcp_opts_wscale (&tc->rcv_opts))
324 opts->flags |= TCP_OPTS_FLAG_WSCALE;
325 opts->wscale = tc->rcv_wscale;
326 len += TCP_OPTION_LEN_WINDOW_SCALE;
329 if (tcp_opts_tstamp (&tc->rcv_opts))
331 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
332 opts->tsval = tcp_time_now ();
333 opts->tsecr = tc->tsval_recent;
334 len += TCP_OPTION_LEN_TIMESTAMP;
337 if (tcp_opts_sack_permitted (&tc->rcv_opts))
339 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
340 len += TCP_OPTION_LEN_SACK_PERMITTED;
343 /* Align to needed boundary */
344 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
349 tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
355 if (tcp_opts_tstamp (&tc->rcv_opts))
357 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
358 opts->tsval = tcp_time_now ();
359 opts->tsecr = tc->tsval_recent;
360 len += TCP_OPTION_LEN_TIMESTAMP;
362 if (tcp_opts_sack_permitted (&tc->rcv_opts))
364 if (vec_len (tc->snd_sacks))
366 opts->flags |= TCP_OPTS_FLAG_SACK;
367 opts->sacks = tc->snd_sacks;
368 opts->n_sack_blocks = clib_min (vec_len (tc->snd_sacks),
369 TCP_OPTS_MAX_SACK_BLOCKS);
370 len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks;
374 /* Align to needed boundary */
375 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
380 tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
385 case TCP_STATE_ESTABLISHED:
386 case TCP_STATE_FIN_WAIT_1:
387 return tcp_make_established_options (tc, opts);
388 case TCP_STATE_SYN_RCVD:
389 return tcp_make_synack_options (tc, opts);
390 case TCP_STATE_SYN_SENT:
391 return tcp_make_syn_options (opts, tc->rcv_wscale);
393 clib_warning ("Not handled!");
399 * Update snd_mss to reflect the effective segment size that we can send
400 * by taking into account all TCP options, including SACKs
403 tcp_update_snd_mss (tcp_connection_t * tc)
405 /* Compute options to be used for connection. These may be reused when
406 * sending data or to compute the effective mss (snd_mss) */
408 tcp_make_options (tc, &tc->snd_opts, TCP_STATE_ESTABLISHED);
410 /* XXX check if MTU has been updated */
411 tc->snd_mss = clib_min (tc->mss, tc->rcv_opts.mss) - tc->snd_opts_len;
412 ASSERT (tc->snd_mss > 0);
416 tcp_init_mss (tcp_connection_t * tc)
418 u16 default_min_mss = 536;
419 tcp_update_rcv_mss (tc);
421 /* TODO cache mss and consider PMTU discovery */
422 tc->snd_mss = clib_min (tc->rcv_opts.mss, tc->mss);
424 if (tc->snd_mss < 45)
426 clib_warning ("snd mss is 0");
427 /* Assume that at least the min default mss works */
428 tc->snd_mss = default_min_mss;
429 tc->rcv_opts.mss = default_min_mss;
432 /* We should have enough space for 40 bytes of options */
433 ASSERT (tc->snd_mss > 45);
435 /* If we use timestamp option, account for it */
436 if (tcp_opts_tstamp (&tc->rcv_opts))
437 tc->snd_mss -= TCP_OPTION_LEN_TIMESTAMP;
441 tcp_alloc_tx_buffers (tcp_main_t * tm, u8 thread_index, u32 n_free_buffers)
443 u32 current_length = vec_len (tm->tx_buffers[thread_index]);
445 vec_validate (tm->tx_buffers[thread_index],
446 current_length + n_free_buffers - 1);
447 _vec_len (tm->tx_buffers[thread_index]) =
448 current_length + vlib_buffer_alloc_from_free_list (vlib_get_main (),
452 VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
453 /* buffer shortage, report failure */
454 if (vec_len (tm->tx_buffers[thread_index]) == 0)
456 clib_warning ("out of buffers");
463 tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx)
466 u32 thread_index = vlib_get_thread_index ();
467 if (PREDICT_FALSE (vec_len (tm->tx_buffers[thread_index]) == 0))
469 if (tcp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE))
472 my_tx_buffers = tm->tx_buffers[thread_index];
473 *bidx = my_tx_buffers[_vec_len (my_tx_buffers) - 1];
474 _vec_len (my_tx_buffers) -= 1;
479 tcp_return_buffer (tcp_main_t * tm)
482 u32 thread_index = vlib_get_thread_index ();
483 my_tx_buffers = tm->tx_buffers[thread_index];
484 _vec_len (my_tx_buffers) += 1;
488 tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
490 if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
491 vlib_buffer_free_one (vm, b->next_buffer);
494 b->current_length = 0;
495 b->total_length_not_including_first_buffer = 0;
496 vnet_buffer (b)->tcp.flags = 0;
498 /* Leave enough space for headers */
499 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
503 tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
505 ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
506 b->flags = VNET_BUFFER_F_LOCALLY_ORIGINATED;
507 b->total_length_not_including_first_buffer = 0;
508 vnet_buffer (b)->tcp.flags = 0;
510 /* Leave enough space for headers */
511 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
518 tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
521 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
522 u8 tcp_opts_len, tcp_hdr_opts_len;
526 wnd = tcp_window_to_advertise (tc, state);
528 /* Make and write options */
529 tcp_opts_len = tcp_make_established_options (tc, snd_opts);
530 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
532 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
533 tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
535 tcp_options_write ((u8 *) (th + 1), snd_opts);
536 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
540 * Convert buffer to ACK
543 tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
545 vlib_main_t *vm = vlib_get_main ();
547 tcp_reuse_buffer (vm, b);
548 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
549 TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
550 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
551 tc->rcv_las = tc->rcv_nxt;
555 * Convert buffer to FIN-ACK
558 tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
560 vlib_main_t *vm = vlib_get_main ();
563 tcp_reuse_buffer (vm, b);
565 flags = TCP_FLAG_FIN | TCP_FLAG_ACK;
566 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags);
568 /* Reset flags, make sure ack is sent */
569 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
575 * Convert buffer to SYN-ACK
578 tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
580 vlib_main_t *vm = vlib_get_main ();
581 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
582 u8 tcp_opts_len, tcp_hdr_opts_len;
587 memset (snd_opts, 0, sizeof (*snd_opts));
589 tcp_reuse_buffer (vm, b);
591 /* Set random initial sequence */
592 time_now = tcp_time_now ();
594 tc->iss = random_u32 (&time_now);
595 tc->snd_una = tc->iss;
596 tc->snd_nxt = tc->iss + 1;
597 tc->snd_una_max = tc->snd_nxt;
599 initial_wnd = tcp_initial_window_to_advertise (tc);
601 /* Make and write options */
602 tcp_opts_len = tcp_make_synack_options (tc, snd_opts);
603 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
605 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
606 tc->rcv_nxt, tcp_hdr_opts_len,
607 TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd);
609 tcp_options_write ((u8 *) (th + 1), snd_opts);
611 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
612 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
614 /* Init retransmit timer */
615 tcp_retransmit_timer_set (tc);
616 TCP_EVT_DBG (TCP_EVT_SYNACK_SENT, tc);
620 tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
623 u32 *to_next, next_index;
626 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
629 /* Default FIB for now */
630 vnet_buffer (b)->sw_if_index[VLIB_TX] = 0;
632 /* Send to IP lookup */
633 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
634 f = vlib_get_frame_to_node (vm, next_index);
636 /* Enqueue the packet */
637 to_next = vlib_frame_vector_args (f);
640 vlib_put_frame_to_node (vm, next_index, f);
644 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
647 tcp_main_t *tm = vnet_get_tcp_main ();
648 u32 thread_index = vlib_get_thread_index ();
649 u32 *to_next, next_index;
652 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
655 /* Decide where to send the packet */
656 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
658 /* Initialize the trajectory trace, if configured */
659 if (VLIB_BUFFER_TRACE_TRAJECTORY > 0)
662 b->pre_data[1] = next_index;
665 /* Get frame to v4/6 output node */
666 f = tm->tx_frames[!is_ip4][thread_index];
669 f = vlib_get_frame_to_node (vm, next_index);
671 tm->tx_frames[!is_ip4][thread_index] = f;
673 to_next = vlib_frame_vector_args (f);
674 to_next[f->n_vectors] = bi;
676 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
678 vlib_put_frame_to_node (vm, next_index, f);
679 tm->tx_frames[!is_ip4][thread_index] = 0;
684 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
686 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
690 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
693 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
697 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
698 tcp_state_t state, u8 thread_index, u8 is_ip4)
703 ip4_address_t src_ip40, dst_ip40;
704 ip6_address_t src_ip60, dst_ip60;
705 u16 src_port, dst_port;
710 /* Find IP and TCP headers */
711 th0 = tcp_buffer_hdr (b0);
713 /* Save src and dst ip */
716 ih4 = vlib_buffer_get_current (b0);
717 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
718 src_ip40.as_u32 = ih4->src_address.as_u32;
719 dst_ip40.as_u32 = ih4->dst_address.as_u32;
723 ih6 = vlib_buffer_get_current (b0);
724 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
725 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
726 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
729 src_port = th0->src_port;
730 dst_port = th0->dst_port;
732 /* Try to determine what/why we're actually resetting */
733 if (state == TCP_STATE_CLOSED)
738 tmp = clib_net_to_host_u32 (th0->seq_number);
740 /* Got a SYN for no listener. */
741 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
742 ack = clib_host_to_net_u32 (tmp + 1);
747 flags = TCP_FLAG_RST;
748 seq = th0->ack_number;
752 tcp_reuse_buffer (vm, b0);
753 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
754 sizeof (tcp_header_t), flags, 0);
758 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
760 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
765 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
767 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
775 * Send reset without reusing existing buffer
777 * It extracts connection info out of original packet
780 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
784 tcp_main_t *tm = vnet_get_tcp_main ();
785 vlib_main_t *vm = vlib_get_main ();
786 u8 tcp_hdr_len, flags = 0;
787 tcp_header_t *th, *pkt_th;
789 ip4_header_t *ih4, *pkt_ih4;
790 ip6_header_t *ih6, *pkt_ih6;
792 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
795 b = vlib_get_buffer (vm, bi);
796 tcp_init_buffer (vm, b);
798 /* Make and write options */
799 tcp_hdr_len = sizeof (tcp_header_t);
803 pkt_ih4 = vlib_buffer_get_current (pkt);
804 pkt_th = ip4_next_header (pkt_ih4);
808 pkt_ih6 = vlib_buffer_get_current (pkt);
809 pkt_th = ip6_next_header (pkt_ih6);
812 if (tcp_ack (pkt_th))
814 flags = TCP_FLAG_RST;
815 seq = pkt_th->ack_number;
816 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
820 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
822 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
825 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
826 seq, ack, tcp_hdr_len, flags, 0);
828 /* Swap src and dst ip */
831 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
832 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
833 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
834 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
839 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
841 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
842 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
843 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
847 tcp_enqueue_to_ip_lookup (vm, b, bi, is_ip4);
848 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
852 * Build and set reset packet for connection
855 tcp_send_reset (tcp_connection_t * tc)
857 vlib_main_t *vm = vlib_get_main ();
858 tcp_main_t *tm = vnet_get_tcp_main ();
862 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
865 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
867 b = vlib_get_buffer (vm, bi);
868 tcp_init_buffer (vm, b);
870 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
871 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
872 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
873 flags = TCP_FLAG_RST;
874 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
875 tc->rcv_nxt, tcp_hdr_opts_len, flags,
877 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
878 ASSERT (opts_write_len == tc->snd_opts_len);
879 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
880 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
884 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
886 tcp_header_t *th = vlib_buffer_get_current (b);
887 vlib_main_t *vm = vlib_get_main ();
891 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
892 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
893 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
900 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
901 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
902 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
910 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
911 * The packet is not forwarded through tcpx_output to avoid doing lookups
912 * in the half_open pool.
915 tcp_send_syn (tcp_connection_t * tc)
919 tcp_main_t *tm = vnet_get_tcp_main ();
920 vlib_main_t *vm = vlib_get_main ();
921 u8 tcp_hdr_opts_len, tcp_opts_len;
925 tcp_options_t snd_opts;
927 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
930 b = vlib_get_buffer (vm, bi);
931 tcp_init_buffer (vm, b);
933 /* Set random initial sequence */
934 time_now = tcp_time_now ();
936 tc->iss = random_u32 (&time_now);
937 tc->snd_una = tc->iss;
938 tc->snd_una_max = tc->snd_nxt = tc->iss + 1;
940 initial_wnd = tcp_initial_window_to_advertise (tc);
942 /* Make and write options */
943 memset (&snd_opts, 0, sizeof (snd_opts));
944 tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale);
945 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
947 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
948 tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
951 tcp_options_write ((u8 *) (th + 1), &snd_opts);
953 /* Measure RTT with this */
954 tc->rtt_ts = tcp_time_now ();
955 tc->rtt_seq = tc->snd_nxt;
957 /* Start retransmit trimer */
958 tcp_timer_set (tc, TCP_TIMER_RETRANSMIT_SYN, tc->rto * TCP_TO_TIMER_TICK);
961 /* Set the connection establishment timer */
962 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
964 tcp_push_ip_hdr (tm, tc, b);
965 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
966 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
970 * Flush tx frame populated by retransmits and timer pops
973 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
975 if (tcp_main.tx_frames[!is_ip4][thread_index])
978 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
979 vlib_put_frame_to_node (vm, next_index,
980 tcp_main.tx_frames[!is_ip4][thread_index]);
981 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
986 * Flush both v4 and v6 tx frames for thread index
989 tcp_flush_frames_to_output (u8 thread_index)
991 vlib_main_t *vm = vlib_get_main ();
992 tcp_flush_frame_to_output (vm, thread_index, 1);
993 tcp_flush_frame_to_output (vm, thread_index, 0);
1000 tcp_send_fin (tcp_connection_t * tc)
1004 tcp_main_t *tm = vnet_get_tcp_main ();
1005 vlib_main_t *vm = vlib_get_main ();
1007 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1009 b = vlib_get_buffer (vm, bi);
1010 /* buffer will be initialized by in tcp_make_fin */
1011 tcp_make_fin (tc, b);
1012 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
1013 tc->flags |= TCP_CONN_FINSNT;
1014 tc->flags &= ~TCP_CONN_FINPNDG;
1015 tcp_retransmit_timer_force_update (tc);
1016 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1020 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1024 case TCP_STATE_ESTABLISHED:
1025 return TCP_FLAG_ACK;
1026 case TCP_STATE_SYN_RCVD:
1027 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1028 case TCP_STATE_SYN_SENT:
1029 return TCP_FLAG_SYN;
1030 case TCP_STATE_LAST_ACK:
1031 case TCP_STATE_FIN_WAIT_1:
1032 if (tc->snd_nxt + 1 < tc->snd_una_max)
1033 return TCP_FLAG_ACK;
1035 return TCP_FLAG_FIN;
1037 clib_warning ("Shouldn't be here!");
1043 * Push TCP header and update connection variables
1046 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1047 tcp_state_t next_state, u8 compute_opts)
1049 u32 advertise_wnd, data_len;
1050 u8 tcp_hdr_opts_len, opts_write_len, flags;
1053 data_len = b->current_length + b->total_length_not_including_first_buffer;
1054 ASSERT (!b->total_length_not_including_first_buffer
1055 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1056 vnet_buffer (b)->tcp.flags = 0;
1059 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1061 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1062 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1063 flags = tcp_make_state_flags (tc, next_state);
1065 /* Push header and options */
1066 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1067 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1069 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1071 ASSERT (opts_write_len == tc->snd_opts_len);
1072 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1075 * Update connection variables
1078 tc->snd_nxt += data_len;
1079 tc->rcv_las = tc->rcv_nxt;
1081 /* TODO this is updated in output as well ... */
1082 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1084 tc->snd_una_max = tc->snd_nxt;
1085 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1088 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1092 tcp_send_ack (tcp_connection_t * tc)
1094 tcp_main_t *tm = vnet_get_tcp_main ();
1095 vlib_main_t *vm = vlib_get_main ();
1101 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1103 b = vlib_get_buffer (vm, bi);
1105 /* Fill in the ACK */
1106 tcp_make_ack (tc, b);
1107 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1111 * Delayed ack timer handler
1113 * Sends delayed ACK when timer expires
1116 tcp_timer_delack_handler (u32 index)
1118 u32 thread_index = vlib_get_thread_index ();
1119 tcp_connection_t *tc;
1121 tc = tcp_connection_get (index, thread_index);
1122 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1127 * Build a retransmit segment
1129 * @return the number of bytes in the segment or 0 if there's nothing to
1133 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1134 u32 max_deq_bytes, vlib_buffer_t ** b)
1136 tcp_main_t *tm = vnet_get_tcp_main ();
1137 vlib_main_t *vm = vlib_get_main ();
1139 u32 start, bi, available_bytes, seg_size;
1142 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1143 ASSERT (max_deq_bytes != 0);
1146 * Make sure we can retransmit something
1148 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1149 available_bytes -= offset;
1150 if (!available_bytes)
1152 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1153 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1155 /* Start is beyond snd_congestion */
1156 start = tc->snd_una + offset;
1157 if (seq_geq (start, tc->snd_congestion))
1160 /* Don't overshoot snd_congestion */
1161 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1163 max_deq_bytes = tc->snd_congestion - start;
1164 if (max_deq_bytes == 0)
1168 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1173 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1176 * Allocate and fill in buffer(s)
1179 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1181 *b = vlib_get_buffer (vm, bi);
1182 data = tcp_init_buffer (vm, *b);
1184 /* Easy case, buffer size greater than mss */
1185 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1187 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1189 ASSERT (n_bytes == max_deq_bytes);
1190 b[0]->current_length = n_bytes;
1191 tcp_push_hdr_i (tc, *b, tc->state, 0);
1193 /* Split mss into multiple buffers */
1196 u32 chain_bi = ~0, n_bufs_per_seg;
1197 u32 thread_index = vlib_get_thread_index ();
1198 u16 n_peeked, len_to_deq, available_bufs;
1199 vlib_buffer_t *chain_b, *prev_b;
1202 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1204 /* Make sure we have enough buffers */
1205 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1206 if (n_bufs_per_seg > available_bufs)
1208 if (tcp_alloc_tx_buffers (tm, thread_index,
1209 VLIB_FRAME_SIZE - available_bufs))
1211 tcp_return_buffer (tm);
1216 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1217 tm->bytes_per_buffer -
1219 b[0]->current_length = n_bytes;
1220 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1221 b[0]->total_length_not_including_first_buffer = 0;
1222 max_deq_bytes -= n_bytes;
1225 for (i = 1; i < n_bufs_per_seg; i++)
1228 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1229 tcp_get_free_buffer_index (tm, &chain_bi);
1230 ASSERT (chain_bi != (u32) ~ 0);
1231 chain_b = vlib_get_buffer (vm, chain_bi);
1232 chain_b->current_data = 0;
1233 data = vlib_buffer_get_current (chain_b);
1234 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1235 offset + n_bytes, len_to_deq);
1236 ASSERT (n_peeked == len_to_deq);
1237 n_bytes += n_peeked;
1238 chain_b->current_length = n_peeked;
1240 chain_b->next_buffer = 0;
1242 /* update previous buffer */
1243 prev_b->next_buffer = chain_bi;
1244 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1246 max_deq_bytes -= n_peeked;
1247 b[0]->total_length_not_including_first_buffer += n_peeked;
1250 tcp_push_hdr_i (tc, *b, tc->state, 0);
1253 ASSERT (n_bytes > 0);
1254 ASSERT (((*b)->current_data + (*b)->current_length) <=
1255 tm->bytes_per_buffer);
1257 if (tcp_in_fastrecovery (tc))
1258 tc->snd_rxt_bytes += n_bytes;
1261 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1266 * Reset congestion control, switch cwnd to loss window and try again.
1269 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1271 tc->prev_ssthresh = tc->ssthresh;
1272 tc->prev_cwnd = tc->cwnd;
1274 /* Cleanly recover cc (also clears up fast retransmit) */
1275 if (tcp_in_fastrecovery (tc))
1276 tcp_cc_fastrecovery_exit (tc);
1278 /* Start again from the beginning */
1279 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1280 tc->cwnd = tcp_loss_wnd (tc);
1281 tc->snd_congestion = tc->snd_una_max;
1283 tcp_recovery_on (tc);
1287 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1289 tcp_main_t *tm = vnet_get_tcp_main ();
1290 vlib_main_t *vm = vlib_get_main ();
1291 u32 thread_index = vlib_get_thread_index ();
1292 tcp_connection_t *tc;
1293 vlib_buffer_t *b = 0;
1298 tc = tcp_half_open_connection_get (index);
1299 /* Note: the connection may have transitioned to ESTABLISHED... */
1300 if (PREDICT_FALSE (tc == 0))
1302 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1306 tc = tcp_connection_get (index, thread_index);
1307 /* Note: the connection may have been closed and pool_put */
1308 if (PREDICT_FALSE (tc == 0))
1310 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1313 if (!tcp_in_recovery (tc) && tc->rto_boff > 0
1314 && tc->state >= TCP_STATE_ESTABLISHED)
1317 tcp_update_rto (tc);
1320 /* Increment RTO backoff (also equal to number of retries) */
1323 /* Go back to first un-acked byte */
1324 tc->snd_nxt = tc->snd_una;
1326 if (tc->state >= TCP_STATE_ESTABLISHED)
1328 /* Lost FIN, retransmit and return */
1329 if (tcp_is_lost_fin (tc))
1335 /* First retransmit timeout */
1336 if (tc->rto_boff == 1)
1337 tcp_rtx_timeout_cc (tc);
1339 /* Exponential backoff */
1340 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1342 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1344 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1345 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1347 /* TODO be less aggressive about this */
1348 scoreboard_clear (&tc->sack_sb);
1354 clib_warning ("retransmit fail: %U", format_tcp_connection, tc,
1356 ASSERT (tc->rto_boff > 1 && tc->snd_una == tc->snd_congestion);
1358 /* Try again eventually */
1359 tcp_retransmit_timer_set (tc);
1363 bi = vlib_get_buffer_index (vm, b);
1365 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1366 if (tc->rto_boff == 1)
1367 tc->snd_rxt_ts = tcp_time_now ();
1369 /* Retransmit for SYN/SYNACK */
1370 else if (tc->state == TCP_STATE_SYN_RCVD || tc->state == TCP_STATE_SYN_SENT)
1372 /* Half-open connection actually moved to established but we were
1373 * waiting for syn retransmit to pop to call cleanup from the right
1375 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1377 ASSERT (tc->state == TCP_STATE_SYN_SENT);
1378 if (tcp_half_open_connection_cleanup (tc))
1380 clib_warning ("could not remove half-open connection");
1386 /* Try without increasing RTO a number of times. If this fails,
1387 * start growing RTO exponentially */
1388 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1389 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1391 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1393 clib_warning ("tcp_get_free_buffer_index FAIL");
1396 b = vlib_get_buffer (vm, bi);
1397 tcp_init_buffer (vm, b);
1398 tcp_push_hdr_i (tc, b, tc->state, 1);
1400 /* Account for the SYN */
1403 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc,
1404 (tc->state == TCP_STATE_SYN_SENT ? 0 : 1));
1408 ASSERT (tc->state == TCP_STATE_CLOSED);
1409 clib_warning ("connection closed ...");
1415 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1417 /* Re-enable retransmit timer */
1418 tcp_retransmit_timer_set (tc);
1422 ASSERT (tc->state == TCP_STATE_SYN_SENT);
1424 /* This goes straight to ipx_lookup */
1425 tcp_push_ip_hdr (tm, tc, b);
1426 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
1428 /* Re-enable retransmit timer */
1429 tcp_timer_set (tc, TCP_TIMER_RETRANSMIT_SYN,
1430 tc->rto * TCP_TO_TIMER_TICK);
1435 tcp_timer_retransmit_handler (u32 index)
1437 tcp_timer_retransmit_handler_i (index, 0);
1441 tcp_timer_retransmit_syn_handler (u32 index)
1443 tcp_timer_retransmit_handler_i (index, 1);
1447 * Got 0 snd_wnd from peer, try to do something about it.
1451 tcp_timer_persist_handler (u32 index)
1453 tcp_main_t *tm = vnet_get_tcp_main ();
1454 vlib_main_t *vm = vlib_get_main ();
1455 u32 thread_index = vlib_get_thread_index ();
1456 tcp_connection_t *tc;
1458 u32 bi, old_snd_nxt, max_snd_bytes, available_bytes, offset;
1462 tc = tcp_connection_get_if_valid (index, thread_index);
1467 /* Make sure timer handle is set to invalid */
1468 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1470 /* Problem already solved or worse */
1471 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1472 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1475 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1476 offset = tc->snd_una_max - tc->snd_una;
1478 /* Reprogram persist if no new bytes available to send. We may have data
1480 if (!available_bytes)
1482 tcp_persist_timer_set (tc);
1486 if (available_bytes <= offset)
1488 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1492 /* Increment RTO backoff */
1494 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1497 * Try to force the first unsent segment (or buffer)
1499 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1501 b = vlib_get_buffer (vm, bi);
1502 data = tcp_init_buffer (vm, b);
1504 tcp_validate_txf_size (tc, offset);
1505 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1506 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1507 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1509 b->current_length = n_bytes;
1510 ASSERT (n_bytes != 0 && (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1
1511 || tcp_timer_is_active (tc,
1512 TCP_TIMER_RETRANSMIT)));
1514 /* Allow updating of snd_una_max but don't update snd_nxt */
1515 old_snd_nxt = tc->snd_nxt;
1516 tcp_push_hdr_i (tc, b, tc->state, 0);
1517 tc->snd_nxt = old_snd_nxt;
1518 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1520 /* Just sent new data, enable retransmit */
1521 tcp_retransmit_timer_update (tc);
1525 * Retransmit first unacked segment
1528 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1530 vlib_main_t *vm = vlib_get_main ();
1532 u32 bi, old_snd_nxt, n_bytes;
1534 old_snd_nxt = tc->snd_nxt;
1535 tc->snd_nxt = tc->snd_una;
1537 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1538 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1541 bi = vlib_get_buffer_index (vm, b);
1542 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1544 tc->snd_nxt = old_snd_nxt;
1548 * Do fast retransmit with SACKs
1551 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1553 vlib_main_t *vm = vlib_get_main ();
1554 u32 n_written = 0, offset, max_bytes;
1555 vlib_buffer_t *b = 0;
1556 sack_scoreboard_hole_t *hole;
1557 sack_scoreboard_t *sb;
1558 u32 bi, old_snd_nxt;
1560 u8 snd_limited = 0, can_rescue = 0;
1562 ASSERT (tcp_in_fastrecovery (tc));
1563 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1565 old_snd_nxt = tc->snd_nxt;
1567 snd_space = tcp_available_snd_space (tc);
1569 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1570 while (hole && snd_space > 0)
1572 hole = scoreboard_next_rxt_hole (sb, hole,
1573 tcp_fastrecovery_sent_1_smss (tc),
1574 &can_rescue, &snd_limited);
1577 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1578 || seq_gt (sb->rescue_rxt,
1579 tc->snd_congestion)))
1582 /* If rescue rxt undefined or less than snd_una then one segment of
1583 * up to SMSS octets that MUST include the highest outstanding
1584 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1585 * RecoveryPoint. HighRxt MUST NOT be updated.
1587 max_bytes = clib_min (tc->snd_mss,
1588 tc->snd_congestion - tc->snd_una);
1589 max_bytes = clib_min (max_bytes, snd_space);
1590 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1591 sb->rescue_rxt = tc->snd_congestion;
1592 tc->snd_nxt = tc->snd_una + offset;
1593 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1596 bi = vlib_get_buffer_index (vm, b);
1597 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1601 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1602 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1605 offset = sb->high_rxt - tc->snd_una;
1606 tc->snd_nxt = sb->high_rxt;
1607 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1609 /* Nothing left to retransmit */
1613 bi = vlib_get_buffer_index (vm, b);
1614 sb->high_rxt += n_written;
1615 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1616 ASSERT (n_written <= snd_space);
1617 snd_space -= n_written;
1620 /* If window allows, send 1 SMSS of new data */
1621 tc->snd_nxt = old_snd_nxt;
1625 * Fast retransmit without SACK info
1628 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1630 vlib_main_t *vm = vlib_get_main ();
1631 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1635 ASSERT (tcp_in_fastrecovery (tc));
1636 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1638 /* Start resending from first un-acked segment */
1639 old_snd_nxt = tc->snd_nxt;
1640 tc->snd_nxt = tc->snd_una;
1641 snd_space = tcp_available_snd_space (tc);
1643 while (snd_space > 0)
1645 offset += n_written;
1646 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1648 /* Nothing left to retransmit */
1652 bi = vlib_get_buffer_index (vm, b);
1653 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1654 snd_space -= n_written;
1657 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1658 tc->snd_nxt = old_snd_nxt;
1662 * Do fast retransmit
1665 tcp_fast_retransmit (tcp_connection_t * tc)
1667 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1668 && scoreboard_first_hole (&tc->sack_sb))
1669 tcp_fast_retransmit_sack (tc);
1671 tcp_fast_retransmit_no_sack (tc);
1675 tcp_session_has_ooo_data (tcp_connection_t * tc)
1677 stream_session_t *s =
1678 stream_session_get (tc->c_s_index, tc->c_thread_index);
1679 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1683 tcp46_output_inline (vlib_main_t * vm,
1684 vlib_node_runtime_t * node,
1685 vlib_frame_t * from_frame, int is_ip4)
1687 u32 n_left_from, next_index, *from, *to_next;
1688 u32 my_thread_index = vm->thread_index;
1690 from = vlib_frame_vector_args (from_frame);
1691 n_left_from = from_frame->n_vectors;
1692 next_index = node->cached_next_index;
1693 tcp_set_time_now (my_thread_index);
1695 while (n_left_from > 0)
1699 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1701 while (n_left_from > 0 && n_left_to_next > 0)
1705 tcp_connection_t *tc0;
1707 tcp_header_t *th0 = 0;
1708 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1715 n_left_to_next -= 1;
1717 b0 = vlib_get_buffer (vm, bi0);
1718 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1720 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1722 error0 = TCP_ERROR_INVALID_CONNECTION;
1723 next0 = TCP_OUTPUT_NEXT_DROP;
1727 th0 = vlib_buffer_get_current (b0);
1728 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1732 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1733 IP_PROTOCOL_TCP, 1);
1734 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1735 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1741 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1742 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1743 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1744 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1745 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1749 /* Filter out DUPACKs if there are no OOO segments left */
1751 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1753 if (!tcp_session_has_ooo_data (tc0))
1755 error0 = TCP_ERROR_FILTERED_DUPACKS;
1756 next0 = TCP_OUTPUT_NEXT_DROP;
1761 /* Stop DELACK timer and fix flags */
1762 tc0->flags &= ~(TCP_CONN_SNDACK);
1763 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1765 /* If not retransmitting
1766 * 1) update snd_una_max (SYN, SYNACK, FIN)
1767 * 2) If we're not tracking an ACK, start tracking */
1768 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1770 tc0->snd_una_max = tc0->snd_nxt;
1771 if (tc0->rtt_ts == 0)
1773 tc0->rtt_ts = tcp_time_now ();
1774 tc0->rtt_seq = tc0->snd_nxt;
1778 /* Set the retransmit timer if not set already and not
1779 * doing a pure ACK */
1780 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1781 && tc0->snd_nxt != tc0->snd_una)
1783 tcp_retransmit_timer_set (tc0);
1788 /* Make sure we haven't lost route to our peer */
1789 if (PREDICT_FALSE (tc0->last_fib_check
1790 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1793 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1795 tc0->last_fib_check = tc0->snd_opts.tsval;
1799 clib_warning ("lost connection to peer");
1800 tcp_connection_reset (tc0);
1805 /* Use pre-computed dpo to set next node */
1806 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1807 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1810 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1811 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1813 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1815 b0->error = node->errors[error0];
1816 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1818 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1821 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1825 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1827 clib_memcpy (&t0->tcp_connection, tc0,
1828 sizeof (t0->tcp_connection));
1831 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1832 n_left_to_next, bi0, next0);
1835 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1838 return from_frame->n_vectors;
1842 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1843 vlib_frame_t * from_frame)
1845 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1849 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1850 vlib_frame_t * from_frame)
1852 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1856 VLIB_REGISTER_NODE (tcp4_output_node) =
1858 .function = tcp4_output,.name = "tcp4-output",
1859 /* Takes a vector of packets. */
1860 .vector_size = sizeof (u32),
1861 .n_errors = TCP_N_ERROR,
1862 .error_strings = tcp_error_strings,
1863 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1865 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1866 foreach_tcp4_output_next
1869 .format_buffer = format_tcp_header,
1870 .format_trace = format_tcp_tx_trace,
1874 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1877 VLIB_REGISTER_NODE (tcp6_output_node) =
1879 .function = tcp6_output,
1880 .name = "tcp6-output",
1881 /* Takes a vector of packets. */
1882 .vector_size = sizeof (u32),
1883 .n_errors = TCP_N_ERROR,
1884 .error_strings = tcp_error_strings,
1885 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1887 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1888 foreach_tcp6_output_next
1891 .format_buffer = format_tcp_header,
1892 .format_trace = format_tcp_tx_trace,
1896 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1899 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1901 tcp_connection_t *tc;
1903 tc = (tcp_connection_t *) tconn;
1904 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1905 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1907 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1909 tc->rtt_ts = tcp_time_now ();
1910 tc->rtt_seq = tc->snd_nxt;
1915 typedef enum _tcp_reset_next
1917 TCP_RESET_NEXT_DROP,
1918 TCP_RESET_NEXT_IP_LOOKUP,
1922 #define foreach_tcp4_reset_next \
1923 _(DROP, "error-drop") \
1924 _(IP_LOOKUP, "ip4-lookup")
1926 #define foreach_tcp6_reset_next \
1927 _(DROP, "error-drop") \
1928 _(IP_LOOKUP, "ip6-lookup")
1931 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
1932 vlib_frame_t * from_frame, u8 is_ip4)
1934 u32 n_left_from, next_index, *from, *to_next;
1935 u32 my_thread_index = vm->thread_index;
1937 from = vlib_frame_vector_args (from_frame);
1938 n_left_from = from_frame->n_vectors;
1940 next_index = node->cached_next_index;
1942 while (n_left_from > 0)
1946 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1948 while (n_left_from > 0 && n_left_to_next > 0)
1954 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
1961 n_left_to_next -= 1;
1963 b0 = vlib_get_buffer (vm, bi0);
1965 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
1966 my_thread_index, is_ip4))
1968 error0 = TCP_ERROR_LOOKUP_DROPS;
1969 next0 = TCP_RESET_NEXT_DROP;
1973 /* Prepare to send to IP lookup */
1974 vnet_buffer (b0)->sw_if_index[VLIB_TX] = 0;
1975 next0 = TCP_RESET_NEXT_IP_LOOKUP;
1978 b0->error = node->errors[error0];
1979 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1980 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1982 th0 = vlib_buffer_get_current (b0);
1984 th0 = ip4_next_header ((ip4_header_t *) th0);
1986 th0 = ip6_next_header ((ip6_header_t *) th0);
1987 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1988 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1991 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1992 n_left_to_next, bi0, next0);
1994 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1996 return from_frame->n_vectors;
2000 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2001 vlib_frame_t * from_frame)
2003 return tcp46_send_reset_inline (vm, node, from_frame, 1);
2007 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2008 vlib_frame_t * from_frame)
2010 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2014 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2015 .function = tcp4_send_reset,
2016 .name = "tcp4-reset",
2017 .vector_size = sizeof (u32),
2018 .n_errors = TCP_N_ERROR,
2019 .error_strings = tcp_error_strings,
2020 .n_next_nodes = TCP_RESET_N_NEXT,
2022 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2023 foreach_tcp4_reset_next
2026 .format_trace = format_tcp_tx_trace,
2030 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2033 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2034 .function = tcp6_send_reset,
2035 .name = "tcp6-reset",
2036 .vector_size = sizeof (u32),
2037 .n_errors = TCP_N_ERROR,
2038 .error_strings = tcp_error_strings,
2039 .n_next_nodes = TCP_RESET_N_NEXT,
2041 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2042 foreach_tcp6_reset_next
2045 .format_trace = format_tcp_tx_trace,
2049 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2052 * fd.io coding-style-patch-verification: ON
2055 * eval: (c-set-style "gnu")