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 u32 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 window)
72 while (wnd_scale < TCP_MAX_WND_SCALE && (window >> wnd_scale) > TCP_WND_MAX)
78 * Update max segment size we're able to process.
80 * The value is constrained by our interface's MTU and IP options. It is
81 * also what we advertise to our peer.
84 tcp_update_rcv_mss (tcp_connection_t * tc)
86 /* TODO find our iface MTU */
87 tc->mss = dummy_mtu - sizeof (tcp_header_t);
91 * TCP's initial window
94 tcp_initial_wnd_unscaled (tcp_connection_t * tc)
96 /* RFC 6928 recommends the value lower. However at the time our connections
97 * are initialized, fifos may not be allocated. Therefore, advertise the
98 * smallest possible unscaled window size and update once fifos are
99 * assigned to the session.
102 tcp_update_rcv_mss (tc);
103 TCP_IW_N_SEGMENTS * tc->mss;
105 return TCP_MIN_RX_FIFO_SIZE;
109 * Compute initial window and scale factor. As per RFC1323, window field in
110 * SYN and SYN-ACK segments is never scaled.
113 tcp_initial_window_to_advertise (tcp_connection_t * tc)
117 /* Initial wnd for SYN. Fifos are not allocated yet.
118 * Use some predefined value. For SYN-ACK we still want the
119 * scale to be computed in the same way */
120 max_fifo = TCP_MAX_RX_FIFO_SIZE;
122 tc->rcv_wscale = tcp_window_compute_scale (max_fifo);
123 tc->rcv_wnd = tcp_initial_wnd_unscaled (tc);
125 return clib_min (tc->rcv_wnd, TCP_WND_MAX);
129 * Compute and return window to advertise, scaled as per RFC1323
132 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
134 if (state < TCP_STATE_ESTABLISHED)
135 return tcp_initial_window_to_advertise (tc);
137 tcp_update_rcv_wnd (tc);
139 if (tc->rcv_wnd == 0)
141 tc->flags |= TCP_CONN_SENT_RCV_WND0;
145 tc->flags &= ~TCP_CONN_SENT_RCV_WND0;
148 return tc->rcv_wnd >> tc->rcv_wscale;
152 tcp_update_rcv_wnd (tcp_connection_t * tc)
155 u32 available_space, max_fifo, wnd;
158 * Figure out how much space we have available
160 available_space = stream_session_max_rx_enqueue (&tc->connection);
161 max_fifo = stream_session_rx_fifo_size (&tc->connection);
163 ASSERT (tc->rcv_opts.mss < max_fifo);
164 if (available_space < tc->rcv_opts.mss && available_space < max_fifo >> 3)
168 * Use the above and what we know about what we've previously advertised
169 * to compute the new window
171 observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las);
172 if (observed_wnd < 0)
175 /* Bad. Thou shalt not shrink */
176 if (available_space < observed_wnd)
179 TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
183 wnd = available_space;
186 /* Make sure we have a multiple of rcv_wscale */
187 if (wnd && tc->rcv_wscale)
189 wnd &= ~(1 << tc->rcv_wscale);
191 wnd = 1 << tc->rcv_wscale;
194 tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
198 * Write TCP options to segment.
201 tcp_options_write (u8 * data, tcp_options_t * opts)
204 u32 buf, seq_len = 4;
206 if (tcp_opts_mss (opts))
208 *data++ = TCP_OPTION_MSS;
209 *data++ = TCP_OPTION_LEN_MSS;
210 buf = clib_host_to_net_u16 (opts->mss);
211 clib_memcpy (data, &buf, sizeof (opts->mss));
212 data += sizeof (opts->mss);
213 opts_len += TCP_OPTION_LEN_MSS;
216 if (tcp_opts_wscale (opts))
218 *data++ = TCP_OPTION_WINDOW_SCALE;
219 *data++ = TCP_OPTION_LEN_WINDOW_SCALE;
220 *data++ = opts->wscale;
221 opts_len += TCP_OPTION_LEN_WINDOW_SCALE;
224 if (tcp_opts_sack_permitted (opts))
226 *data++ = TCP_OPTION_SACK_PERMITTED;
227 *data++ = TCP_OPTION_LEN_SACK_PERMITTED;
228 opts_len += TCP_OPTION_LEN_SACK_PERMITTED;
231 if (tcp_opts_tstamp (opts))
233 *data++ = TCP_OPTION_TIMESTAMP;
234 *data++ = TCP_OPTION_LEN_TIMESTAMP;
235 buf = clib_host_to_net_u32 (opts->tsval);
236 clib_memcpy (data, &buf, sizeof (opts->tsval));
237 data += sizeof (opts->tsval);
238 buf = clib_host_to_net_u32 (opts->tsecr);
239 clib_memcpy (data, &buf, sizeof (opts->tsecr));
240 data += sizeof (opts->tsecr);
241 opts_len += TCP_OPTION_LEN_TIMESTAMP;
244 if (tcp_opts_sack (opts))
247 u32 n_sack_blocks = clib_min (vec_len (opts->sacks),
248 TCP_OPTS_MAX_SACK_BLOCKS);
250 if (n_sack_blocks != 0)
252 *data++ = TCP_OPTION_SACK_BLOCK;
253 *data++ = 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
254 for (i = 0; i < n_sack_blocks; i++)
256 buf = clib_host_to_net_u32 (opts->sacks[i].start);
257 clib_memcpy (data, &buf, seq_len);
259 buf = clib_host_to_net_u32 (opts->sacks[i].end);
260 clib_memcpy (data, &buf, seq_len);
263 opts_len += 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
267 /* Terminate TCP options */
270 *data++ = TCP_OPTION_EOL;
271 opts_len += TCP_OPTION_LEN_EOL;
274 /* Pad with zeroes to a u32 boundary */
277 *data++ = TCP_OPTION_NOOP;
278 opts_len += TCP_OPTION_LEN_NOOP;
284 tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale)
288 opts->flags |= TCP_OPTS_FLAG_MSS;
289 opts->mss = dummy_mtu; /*XXX discover that */
290 len += TCP_OPTION_LEN_MSS;
292 opts->flags |= TCP_OPTS_FLAG_WSCALE;
293 opts->wscale = wnd_scale;
294 len += TCP_OPTION_LEN_WINDOW_SCALE;
296 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
297 opts->tsval = tcp_time_now ();
299 len += TCP_OPTION_LEN_TIMESTAMP;
303 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
304 len += TCP_OPTION_LEN_SACK_PERMITTED;
307 /* Align to needed boundary */
308 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
313 tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
317 opts->flags |= TCP_OPTS_FLAG_MSS;
319 len += TCP_OPTION_LEN_MSS;
321 if (tcp_opts_wscale (&tc->rcv_opts))
323 opts->flags |= TCP_OPTS_FLAG_WSCALE;
324 opts->wscale = tc->rcv_wscale;
325 len += TCP_OPTION_LEN_WINDOW_SCALE;
328 if (tcp_opts_tstamp (&tc->rcv_opts))
330 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
331 opts->tsval = tcp_time_now ();
332 opts->tsecr = tc->tsval_recent;
333 len += TCP_OPTION_LEN_TIMESTAMP;
336 if (tcp_opts_sack_permitted (&tc->rcv_opts))
338 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
339 len += TCP_OPTION_LEN_SACK_PERMITTED;
342 /* Align to needed boundary */
343 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
348 tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
354 if (tcp_opts_tstamp (&tc->rcv_opts))
356 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
357 opts->tsval = tcp_time_now ();
358 opts->tsecr = tc->tsval_recent;
359 len += TCP_OPTION_LEN_TIMESTAMP;
361 if (tcp_opts_sack_permitted (&tc->rcv_opts))
363 if (vec_len (tc->snd_sacks))
365 opts->flags |= TCP_OPTS_FLAG_SACK;
366 opts->sacks = tc->snd_sacks;
367 opts->n_sack_blocks = clib_min (vec_len (tc->snd_sacks),
368 TCP_OPTS_MAX_SACK_BLOCKS);
369 len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks;
373 /* Align to needed boundary */
374 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
379 tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
384 case TCP_STATE_ESTABLISHED:
385 case TCP_STATE_FIN_WAIT_1:
386 return tcp_make_established_options (tc, opts);
387 case TCP_STATE_SYN_RCVD:
388 return tcp_make_synack_options (tc, opts);
389 case TCP_STATE_SYN_SENT:
390 return tcp_make_syn_options (opts, tc->rcv_wscale);
392 clib_warning ("Not handled!");
398 * Update snd_mss to reflect the effective segment size that we can send
399 * by taking into account all TCP options, including SACKs
402 tcp_update_snd_mss (tcp_connection_t * tc)
404 /* Compute options to be used for connection. These may be reused when
405 * sending data or to compute the effective mss (snd_mss) */
407 tcp_make_options (tc, &tc->snd_opts, TCP_STATE_ESTABLISHED);
409 /* XXX check if MTU has been updated */
410 tc->snd_mss = clib_min (tc->mss, tc->rcv_opts.mss) - tc->snd_opts_len;
411 ASSERT (tc->snd_mss > 0);
415 tcp_init_mss (tcp_connection_t * tc)
417 u16 default_min_mss = 536;
418 tcp_update_rcv_mss (tc);
420 /* TODO cache mss and consider PMTU discovery */
421 tc->snd_mss = clib_min (tc->rcv_opts.mss, tc->mss);
423 if (tc->snd_mss < 45)
425 clib_warning ("snd mss is 0");
426 /* Assume that at least the min default mss works */
427 tc->snd_mss = default_min_mss;
428 tc->rcv_opts.mss = default_min_mss;
431 /* We should have enough space for 40 bytes of options */
432 ASSERT (tc->snd_mss > 45);
434 /* If we use timestamp option, account for it */
435 if (tcp_opts_tstamp (&tc->rcv_opts))
436 tc->snd_mss -= TCP_OPTION_LEN_TIMESTAMP;
440 tcp_alloc_tx_buffers (tcp_main_t * tm, u8 thread_index, u32 n_free_buffers)
442 vlib_main_t *vm = vlib_get_main ();
443 u32 current_length = vec_len (tm->tx_buffers[thread_index]);
446 vec_validate (tm->tx_buffers[thread_index],
447 current_length + n_free_buffers - 1);
449 vlib_buffer_alloc (vm, &tm->tx_buffers[thread_index][current_length],
451 _vec_len (tm->tx_buffers[thread_index]) = current_length + n_allocated;
452 /* buffer shortage, report failure */
453 if (vec_len (tm->tx_buffers[thread_index]) == 0)
455 clib_warning ("out of buffers");
462 tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx)
465 u32 thread_index = vlib_get_thread_index ();
467 TCP_DBG_BUFFER_ALLOC_MAYBE_FAIL (thread_index);
469 if (PREDICT_FALSE (vec_len (tm->tx_buffers[thread_index]) == 0))
471 if (tcp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE))
474 my_tx_buffers = tm->tx_buffers[thread_index];
475 *bidx = my_tx_buffers[vec_len (my_tx_buffers) - 1];
476 _vec_len (my_tx_buffers) -= 1;
481 tcp_return_buffer (tcp_main_t * tm)
483 _vec_len (tm->tx_buffers[vlib_get_thread_index ()]) += 1;
487 tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
489 if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
490 vlib_buffer_free_one (vm, b->next_buffer);
491 /* Zero all flags but free list index and trace flag */
492 b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1;
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 &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
507 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
508 b->total_length_not_including_first_buffer = 0;
509 vnet_buffer (b)->tcp.flags = 0;
510 VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b);
511 /* Leave enough space for headers */
512 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
519 tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
522 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
523 u8 tcp_opts_len, tcp_hdr_opts_len;
527 wnd = tcp_window_to_advertise (tc, state);
529 /* Make and write options */
530 tcp_opts_len = tcp_make_established_options (tc, snd_opts);
531 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
533 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
534 tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
536 tcp_options_write ((u8 *) (th + 1), snd_opts);
537 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
541 * Convert buffer to ACK
544 tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
546 vlib_main_t *vm = vlib_get_main ();
548 tcp_reuse_buffer (vm, b);
549 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
550 TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
551 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
552 tc->rcv_las = tc->rcv_nxt;
556 * Convert buffer to FIN-ACK
559 tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
561 vlib_main_t *vm = vlib_get_main ();
564 tcp_reuse_buffer (vm, b);
566 flags = TCP_FLAG_FIN | TCP_FLAG_ACK;
567 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags);
569 /* Reset flags, make sure ack is sent */
570 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
574 * Convert buffer to SYN
577 tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
579 u8 tcp_hdr_opts_len, tcp_opts_len;
582 tcp_options_t snd_opts;
584 initial_wnd = tcp_initial_window_to_advertise (tc);
586 /* Make and write options */
587 memset (&snd_opts, 0, sizeof (snd_opts));
588 tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale);
589 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
591 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
592 tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
594 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
595 tcp_options_write ((u8 *) (th + 1), &snd_opts);
599 * Convert buffer to SYN-ACK
602 tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
604 vlib_main_t *vm = vlib_get_main ();
605 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
606 u8 tcp_opts_len, tcp_hdr_opts_len;
610 memset (snd_opts, 0, sizeof (*snd_opts));
611 tcp_reuse_buffer (vm, b);
613 initial_wnd = tcp_initial_window_to_advertise (tc);
614 tcp_opts_len = tcp_make_synack_options (tc, snd_opts);
615 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
617 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
618 tc->rcv_nxt, tcp_hdr_opts_len,
619 TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd);
620 tcp_options_write ((u8 *) (th + 1), snd_opts);
622 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
623 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
625 /* Init retransmit timer. Use update instead of set because of
627 tcp_retransmit_timer_force_update (tc);
628 TCP_EVT_DBG (TCP_EVT_SYNACK_SENT, tc);
632 tcp_enqueue_to_ip_lookup_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
635 tcp_main_t *tm = vnet_get_tcp_main ();
636 u32 thread_index = vlib_get_thread_index ();
637 u32 *to_next, next_index;
640 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
643 /* Default FIB for now */
644 vnet_buffer (b)->sw_if_index[VLIB_TX] = ~0;
646 /* Send to IP lookup */
647 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
648 tcp_trajectory_add_start (b, 1);
650 f = tm->ip_lookup_tx_frames[!is_ip4][thread_index];
653 f = vlib_get_frame_to_node (vm, next_index);
655 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = f;
658 to_next = vlib_frame_vector_args (f);
659 to_next[f->n_vectors] = bi;
661 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
663 vlib_put_frame_to_node (vm, next_index, f);
664 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
669 tcp_enqueue_to_ip_lookup_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
672 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, 1);
676 tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
679 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, 0);
683 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
686 tcp_main_t *tm = vnet_get_tcp_main ();
687 u32 thread_index = vlib_get_thread_index ();
688 u32 *to_next, next_index;
691 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
694 /* Decide where to send the packet */
695 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
696 tcp_trajectory_add_start (b, 2);
698 /* Get frame to v4/6 output node */
699 f = tm->tx_frames[!is_ip4][thread_index];
702 f = vlib_get_frame_to_node (vm, next_index);
704 tm->tx_frames[!is_ip4][thread_index] = f;
706 to_next = vlib_frame_vector_args (f);
707 to_next[f->n_vectors] = bi;
709 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
711 vlib_put_frame_to_node (vm, next_index, f);
712 tm->tx_frames[!is_ip4][thread_index] = 0;
717 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
719 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
723 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
726 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
730 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
731 tcp_state_t state, u8 thread_index, u8 is_ip4)
736 ip4_address_t src_ip40, dst_ip40;
737 ip6_address_t src_ip60, dst_ip60;
738 u16 src_port, dst_port;
743 /* Find IP and TCP headers */
744 th0 = tcp_buffer_hdr (b0);
746 /* Save src and dst ip */
749 ih4 = vlib_buffer_get_current (b0);
750 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
751 src_ip40.as_u32 = ih4->src_address.as_u32;
752 dst_ip40.as_u32 = ih4->dst_address.as_u32;
756 ih6 = vlib_buffer_get_current (b0);
757 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
758 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
759 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
762 src_port = th0->src_port;
763 dst_port = th0->dst_port;
765 /* Try to determine what/why we're actually resetting */
766 if (state == TCP_STATE_CLOSED)
771 tmp = clib_net_to_host_u32 (th0->seq_number);
773 /* Got a SYN for no listener. */
774 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
775 ack = clib_host_to_net_u32 (tmp + 1);
780 flags = TCP_FLAG_RST;
781 seq = th0->ack_number;
785 tcp_reuse_buffer (vm, b0);
786 tcp_trajectory_add_start (b0, 4);
787 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
788 sizeof (tcp_header_t), flags, 0);
792 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
794 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
799 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
801 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
809 * Send reset without reusing existing buffer
811 * It extracts connection info out of original packet
814 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
818 tcp_main_t *tm = vnet_get_tcp_main ();
819 vlib_main_t *vm = vlib_get_main ();
820 u8 tcp_hdr_len, flags = 0;
821 tcp_header_t *th, *pkt_th;
823 ip4_header_t *ih4, *pkt_ih4;
824 ip6_header_t *ih6, *pkt_ih6;
826 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
829 b = vlib_get_buffer (vm, bi);
830 tcp_init_buffer (vm, b);
832 /* Make and write options */
833 tcp_hdr_len = sizeof (tcp_header_t);
837 pkt_ih4 = vlib_buffer_get_current (pkt);
838 pkt_th = ip4_next_header (pkt_ih4);
842 pkt_ih6 = vlib_buffer_get_current (pkt);
843 pkt_th = ip6_next_header (pkt_ih6);
846 if (tcp_ack (pkt_th))
848 flags = TCP_FLAG_RST;
849 seq = pkt_th->ack_number;
850 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
854 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
856 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
859 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
860 seq, ack, tcp_hdr_len, flags, 0);
862 /* Swap src and dst ip */
865 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
866 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
867 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
868 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
873 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
875 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
876 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
877 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
881 tcp_enqueue_to_ip_lookup_now (vm, b, bi, is_ip4);
882 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
886 * Build and set reset packet for connection
889 tcp_send_reset (tcp_connection_t * tc)
891 vlib_main_t *vm = vlib_get_main ();
892 tcp_main_t *tm = vnet_get_tcp_main ();
896 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
899 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
901 b = vlib_get_buffer (vm, bi);
902 tcp_init_buffer (vm, b);
904 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
905 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
906 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
907 flags = TCP_FLAG_RST;
908 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
909 tc->rcv_nxt, tcp_hdr_opts_len, flags,
911 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
912 ASSERT (opts_write_len == tc->snd_opts_len);
913 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
917 ih4 = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip.ip4,
918 &tc->c_rmt_ip.ip4, IP_PROTOCOL_TCP, 0);
919 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
925 ih6 = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip.ip6,
926 &tc->c_rmt_ip.ip6, IP_PROTOCOL_TCP);
927 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
930 tcp_enqueue_to_ip_lookup_now (vm, b, bi, tc->c_is_ip4);
931 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
935 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
937 tcp_header_t *th = vlib_buffer_get_current (b);
938 vlib_main_t *vm = vlib_get_main ();
942 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
943 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
944 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
951 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
952 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
953 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
961 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
962 * The packet is not forwarded through tcpx_output to avoid doing lookups
963 * in the half_open pool.
966 tcp_send_syn (tcp_connection_t * tc)
970 tcp_main_t *tm = vnet_get_tcp_main ();
971 vlib_main_t *vm = vlib_get_main ();
974 * Setup retransmit and establish timers before requesting buffer
975 * such that we can return if we've ran out.
977 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
978 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
979 tc->rto * TCP_TO_TIMER_TICK);
981 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
984 b = vlib_get_buffer (vm, bi);
985 tcp_init_buffer (vm, b);
986 tcp_make_syn (tc, b);
988 /* Measure RTT with this */
989 tc->rtt_ts = tcp_time_now ();
990 tc->rtt_seq = tc->snd_nxt;
993 tcp_push_ip_hdr (tm, tc, b);
994 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
995 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
999 * Flush tx frame populated by retransmits and timer pops
1002 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1004 if (tcp_main.tx_frames[!is_ip4][thread_index])
1007 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
1008 vlib_put_frame_to_node (vm, next_index,
1009 tcp_main.tx_frames[!is_ip4][thread_index]);
1010 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
1015 * Flush ip lookup tx frames populated by timer pops
1018 tcp_flush_frame_to_ip_lookup (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1020 if (tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index])
1023 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
1024 vlib_put_frame_to_node (vm, next_index,
1025 tcp_main.ip_lookup_tx_frames[!is_ip4]
1027 tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
1032 * Flush v4 and v6 tcp and ip-lookup tx frames for thread index
1035 tcp_flush_frames_to_output (u8 thread_index)
1037 vlib_main_t *vm = vlib_get_main ();
1038 tcp_flush_frame_to_output (vm, thread_index, 1);
1039 tcp_flush_frame_to_output (vm, thread_index, 0);
1040 tcp_flush_frame_to_ip_lookup (vm, thread_index, 1);
1041 tcp_flush_frame_to_ip_lookup (vm, thread_index, 0);
1048 tcp_send_fin (tcp_connection_t * tc)
1050 tcp_main_t *tm = vnet_get_tcp_main ();
1051 vlib_main_t *vm = vlib_get_main ();
1056 tcp_retransmit_timer_force_update (tc);
1057 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1059 b = vlib_get_buffer (vm, bi);
1060 fin_snt = tc->flags & TCP_CONN_FINSNT;
1062 tc->snd_nxt = tc->snd_una;
1063 tcp_make_fin (tc, b);
1064 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
1067 tc->flags |= TCP_CONN_FINSNT;
1068 tc->flags &= ~TCP_CONN_FINPNDG;
1069 /* Account for the FIN */
1070 tc->snd_una_max += 1;
1071 tc->snd_nxt = tc->snd_una_max;
1075 tc->snd_nxt = tc->snd_una_max;
1077 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1081 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1085 case TCP_STATE_ESTABLISHED:
1086 return TCP_FLAG_ACK;
1087 case TCP_STATE_SYN_RCVD:
1088 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1089 case TCP_STATE_SYN_SENT:
1090 return TCP_FLAG_SYN;
1091 case TCP_STATE_LAST_ACK:
1092 case TCP_STATE_FIN_WAIT_1:
1093 if (tc->snd_nxt + 1 < tc->snd_una_max)
1094 return TCP_FLAG_ACK;
1096 return TCP_FLAG_FIN;
1098 clib_warning ("Shouldn't be here!");
1104 * Push TCP header and update connection variables
1107 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1108 tcp_state_t next_state, u8 compute_opts)
1110 u32 advertise_wnd, data_len;
1111 u8 tcp_hdr_opts_len, opts_write_len, flags;
1114 data_len = b->current_length + b->total_length_not_including_first_buffer;
1115 ASSERT (!b->total_length_not_including_first_buffer
1116 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1117 vnet_buffer (b)->tcp.flags = 0;
1120 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1122 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1123 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1124 flags = tcp_make_state_flags (tc, next_state);
1126 /* Push header and options */
1127 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1128 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1130 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1132 ASSERT (opts_write_len == tc->snd_opts_len);
1133 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1136 * Update connection variables
1139 tc->snd_nxt += data_len;
1140 tc->rcv_las = tc->rcv_nxt;
1142 /* TODO this is updated in output as well ... */
1143 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1145 tc->snd_una_max = tc->snd_nxt;
1146 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1149 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1153 tcp_send_ack (tcp_connection_t * tc)
1155 tcp_main_t *tm = vnet_get_tcp_main ();
1156 vlib_main_t *vm = vlib_get_main ();
1162 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1164 b = vlib_get_buffer (vm, bi);
1166 /* Fill in the ACK */
1167 tcp_make_ack (tc, b);
1168 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1172 * Delayed ack timer handler
1174 * Sends delayed ACK when timer expires
1177 tcp_timer_delack_handler (u32 index)
1179 u32 thread_index = vlib_get_thread_index ();
1180 tcp_connection_t *tc;
1182 tc = tcp_connection_get (index, thread_index);
1183 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1188 * Build a retransmit segment
1190 * @return the number of bytes in the segment or 0 if there's nothing to
1194 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1195 u32 max_deq_bytes, vlib_buffer_t ** b)
1197 tcp_main_t *tm = vnet_get_tcp_main ();
1198 vlib_main_t *vm = vlib_get_main ();
1200 u32 start, bi, available_bytes, seg_size;
1203 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1204 ASSERT (max_deq_bytes != 0);
1207 * Make sure we can retransmit something
1209 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1210 ASSERT (available_bytes >= offset);
1211 available_bytes -= offset;
1212 if (!available_bytes)
1214 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1215 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1217 /* Start is beyond snd_congestion */
1218 start = tc->snd_una + offset;
1219 if (seq_geq (start, tc->snd_congestion))
1222 /* Don't overshoot snd_congestion */
1223 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1225 max_deq_bytes = tc->snd_congestion - start;
1226 if (max_deq_bytes == 0)
1230 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1235 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1238 * Allocate and fill in buffer(s)
1241 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1243 *b = vlib_get_buffer (vm, bi);
1244 data = tcp_init_buffer (vm, *b);
1246 /* Easy case, buffer size greater than mss */
1247 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1249 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1251 ASSERT (n_bytes == max_deq_bytes);
1252 b[0]->current_length = n_bytes;
1253 tcp_push_hdr_i (tc, *b, tc->state, 0);
1255 /* Split mss into multiple buffers */
1258 u32 chain_bi = ~0, n_bufs_per_seg;
1259 u32 thread_index = vlib_get_thread_index ();
1260 u16 n_peeked, len_to_deq, available_bufs;
1261 vlib_buffer_t *chain_b, *prev_b;
1264 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1266 /* Make sure we have enough buffers */
1267 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1268 if (n_bufs_per_seg > available_bufs)
1270 if (tcp_alloc_tx_buffers (tm, thread_index,
1271 VLIB_FRAME_SIZE - available_bufs))
1273 tcp_return_buffer (tm);
1279 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1280 tm->bytes_per_buffer -
1282 b[0]->current_length = n_bytes;
1283 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1284 b[0]->total_length_not_including_first_buffer = 0;
1285 max_deq_bytes -= n_bytes;
1288 for (i = 1; i < n_bufs_per_seg; i++)
1291 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1292 tcp_get_free_buffer_index (tm, &chain_bi);
1293 ASSERT (chain_bi != (u32) ~ 0);
1294 chain_b = vlib_get_buffer (vm, chain_bi);
1295 chain_b->current_data = 0;
1296 data = vlib_buffer_get_current (chain_b);
1297 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1298 offset + n_bytes, len_to_deq);
1299 ASSERT (n_peeked == len_to_deq);
1300 n_bytes += n_peeked;
1301 chain_b->current_length = n_peeked;
1302 chain_b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
1303 chain_b->next_buffer = 0;
1305 /* update previous buffer */
1306 prev_b->next_buffer = chain_bi;
1307 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1309 max_deq_bytes -= n_peeked;
1310 b[0]->total_length_not_including_first_buffer += n_peeked;
1313 tcp_push_hdr_i (tc, *b, tc->state, 0);
1316 ASSERT (n_bytes > 0);
1317 ASSERT (((*b)->current_data + (*b)->current_length) <=
1318 tm->bytes_per_buffer);
1320 if (tcp_in_fastrecovery (tc))
1321 tc->snd_rxt_bytes += n_bytes;
1324 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1329 * Reset congestion control, switch cwnd to loss window and try again.
1332 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1334 tc->prev_ssthresh = tc->ssthresh;
1335 tc->prev_cwnd = tc->cwnd;
1337 /* Cleanly recover cc (also clears up fast retransmit) */
1338 if (tcp_in_fastrecovery (tc))
1339 tcp_cc_fastrecovery_exit (tc);
1341 /* Start again from the beginning */
1342 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1343 tc->cwnd = tcp_loss_wnd (tc);
1344 tc->snd_congestion = tc->snd_una_max;
1346 tcp_recovery_on (tc);
1350 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1352 tcp_main_t *tm = vnet_get_tcp_main ();
1353 vlib_main_t *vm = vlib_get_main ();
1354 u32 thread_index = vlib_get_thread_index ();
1355 tcp_connection_t *tc;
1356 vlib_buffer_t *b = 0;
1361 tc = tcp_half_open_connection_get (index);
1362 /* Note: the connection may have transitioned to ESTABLISHED... */
1363 if (PREDICT_FALSE (tc == 0))
1365 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1369 tc = tcp_connection_get (index, thread_index);
1370 /* Note: the connection may have been closed and pool_put */
1371 if (PREDICT_FALSE (tc == 0))
1373 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1376 if (tc->state >= TCP_STATE_ESTABLISHED)
1378 /* Lost FIN, retransmit and return */
1379 if (tcp_is_lost_fin (tc))
1383 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1387 /* Shouldn't be here */
1388 if (tc->snd_una == tc->snd_una_max)
1390 tcp_recovery_off (tc);
1394 /* We're not in recovery so make sure rto_boff is 0 */
1395 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1398 tcp_update_rto (tc);
1401 /* Increment RTO backoff (also equal to number of retries) and go back
1402 * to first un-acked byte */
1405 /* First retransmit timeout */
1406 if (tc->rto_boff == 1)
1407 tcp_rtx_timeout_cc (tc);
1409 tc->snd_nxt = tc->snd_una;
1410 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1412 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1414 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1415 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1417 /* TODO be less aggressive about this */
1418 scoreboard_clear (&tc->sack_sb);
1422 tcp_retransmit_timer_set (tc);
1426 bi = vlib_get_buffer_index (vm, b);
1428 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1429 if (tc->rto_boff == 1)
1430 tc->snd_rxt_ts = tcp_time_now ();
1432 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1433 tcp_retransmit_timer_update (tc);
1435 /* Retransmit for SYN */
1436 else if (tc->state == TCP_STATE_SYN_SENT)
1438 /* Half-open connection actually moved to established but we were
1439 * waiting for syn retransmit to pop to call cleanup from the right
1441 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1443 if (tcp_half_open_connection_cleanup (tc))
1445 clib_warning ("could not remove half-open connection");
1451 /* Try without increasing RTO a number of times. If this fails,
1452 * start growing RTO exponentially */
1454 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1455 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1457 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
1458 tc->rto * TCP_TO_TIMER_TICK);
1460 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1463 b = vlib_get_buffer (vm, bi);
1464 tcp_init_buffer (vm, b);
1465 tcp_make_syn (tc, b);
1468 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1470 /* This goes straight to ipx_lookup. Retransmit timer set already */
1471 tcp_push_ip_hdr (tm, tc, b);
1472 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
1474 /* Retransmit SYN-ACK */
1475 else if (tc->state == TCP_STATE_SYN_RCVD)
1478 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1479 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1482 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1484 tcp_retransmit_timer_force_update (tc);
1488 b = vlib_get_buffer (vm, bi);
1489 tcp_make_synack (tc, b);
1490 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1492 /* Retransmit timer already updated, just enqueue to output */
1493 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1497 ASSERT (tc->state == TCP_STATE_CLOSED);
1503 tcp_timer_retransmit_handler (u32 index)
1505 tcp_timer_retransmit_handler_i (index, 0);
1509 tcp_timer_retransmit_syn_handler (u32 index)
1511 tcp_timer_retransmit_handler_i (index, 1);
1515 * Got 0 snd_wnd from peer, try to do something about it.
1519 tcp_timer_persist_handler (u32 index)
1521 tcp_main_t *tm = vnet_get_tcp_main ();
1522 vlib_main_t *vm = vlib_get_main ();
1523 u32 thread_index = vlib_get_thread_index ();
1524 tcp_connection_t *tc;
1526 u32 bi, max_snd_bytes, available_bytes, offset;
1530 tc = tcp_connection_get_if_valid (index, thread_index);
1535 /* Make sure timer handle is set to invalid */
1536 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1538 /* Problem already solved or worse */
1539 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1540 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1543 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1544 offset = tc->snd_una_max - tc->snd_una;
1546 /* Reprogram persist if no new bytes available to send. We may have data
1548 if (!available_bytes)
1550 tcp_persist_timer_set (tc);
1554 if (available_bytes <= offset)
1556 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1560 /* Increment RTO backoff */
1562 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1565 * Try to force the first unsent segment (or buffer)
1567 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1569 b = vlib_get_buffer (vm, bi);
1570 data = tcp_init_buffer (vm, b);
1572 tcp_validate_txf_size (tc, offset);
1573 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1574 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1575 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1577 b->current_length = n_bytes;
1578 ASSERT (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)
1579 || tc->snd_nxt == tc->snd_una_max
1580 || tc->rto_boff > 1));
1582 tcp_push_hdr_i (tc, b, tc->state, 0);
1583 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1585 /* Just sent new data, enable retransmit */
1586 tcp_retransmit_timer_update (tc);
1590 * Retransmit first unacked segment
1593 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1595 vlib_main_t *vm = vlib_get_main ();
1597 u32 bi, old_snd_nxt, n_bytes;
1599 old_snd_nxt = tc->snd_nxt;
1600 tc->snd_nxt = tc->snd_una;
1602 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1603 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1606 bi = vlib_get_buffer_index (vm, b);
1607 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1609 tc->snd_nxt = old_snd_nxt;
1613 * Do fast retransmit with SACKs
1616 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1618 vlib_main_t *vm = vlib_get_main ();
1619 u32 n_written = 0, offset, max_bytes;
1620 vlib_buffer_t *b = 0;
1621 sack_scoreboard_hole_t *hole;
1622 sack_scoreboard_t *sb;
1623 u32 bi, old_snd_nxt;
1625 u8 snd_limited = 0, can_rescue = 0;
1627 ASSERT (tcp_in_fastrecovery (tc));
1628 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1630 old_snd_nxt = tc->snd_nxt;
1632 snd_space = tcp_available_snd_space (tc);
1634 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1635 while (hole && snd_space > 0)
1637 hole = scoreboard_next_rxt_hole (sb, hole,
1638 tcp_fastrecovery_sent_1_smss (tc),
1639 &can_rescue, &snd_limited);
1642 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1643 || seq_gt (sb->rescue_rxt,
1644 tc->snd_congestion)))
1647 /* If rescue rxt undefined or less than snd_una then one segment of
1648 * up to SMSS octets that MUST include the highest outstanding
1649 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1650 * RecoveryPoint. HighRxt MUST NOT be updated.
1652 max_bytes = clib_min (tc->snd_mss,
1653 tc->snd_congestion - tc->snd_una);
1654 max_bytes = clib_min (max_bytes, snd_space);
1655 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1656 sb->rescue_rxt = tc->snd_congestion;
1657 tc->snd_nxt = tc->snd_una + offset;
1658 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1661 bi = vlib_get_buffer_index (vm, b);
1662 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1666 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1667 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1670 offset = sb->high_rxt - tc->snd_una;
1671 tc->snd_nxt = sb->high_rxt;
1672 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1674 /* Nothing left to retransmit */
1678 bi = vlib_get_buffer_index (vm, b);
1679 sb->high_rxt += n_written;
1680 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1681 ASSERT (n_written <= snd_space);
1682 snd_space -= n_written;
1685 /* If window allows, send 1 SMSS of new data */
1686 tc->snd_nxt = old_snd_nxt;
1690 * Fast retransmit without SACK info
1693 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1695 vlib_main_t *vm = vlib_get_main ();
1696 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1700 ASSERT (tcp_in_fastrecovery (tc));
1701 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1703 /* Start resending from first un-acked segment */
1704 old_snd_nxt = tc->snd_nxt;
1705 tc->snd_nxt = tc->snd_una;
1706 snd_space = tcp_available_snd_space (tc);
1708 while (snd_space > 0)
1710 offset += n_written;
1711 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1713 /* Nothing left to retransmit */
1717 bi = vlib_get_buffer_index (vm, b);
1718 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1719 snd_space -= n_written;
1722 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1723 tc->snd_nxt = old_snd_nxt;
1727 * Do fast retransmit
1730 tcp_fast_retransmit (tcp_connection_t * tc)
1732 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1733 && scoreboard_first_hole (&tc->sack_sb))
1734 tcp_fast_retransmit_sack (tc);
1736 tcp_fast_retransmit_no_sack (tc);
1740 tcp_session_has_ooo_data (tcp_connection_t * tc)
1742 stream_session_t *s = session_get (tc->c_s_index, tc->c_thread_index);
1743 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1747 tcp46_output_inline (vlib_main_t * vm,
1748 vlib_node_runtime_t * node,
1749 vlib_frame_t * from_frame, int is_ip4)
1751 u32 n_left_from, next_index, *from, *to_next;
1752 u32 my_thread_index = vm->thread_index;
1754 from = vlib_frame_vector_args (from_frame);
1755 n_left_from = from_frame->n_vectors;
1756 next_index = node->cached_next_index;
1757 tcp_set_time_now (my_thread_index);
1759 while (n_left_from > 0)
1763 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1765 while (n_left_from > 0 && n_left_to_next > 0)
1769 tcp_connection_t *tc0;
1771 tcp_header_t *th0 = 0;
1772 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1779 n_left_to_next -= 1;
1781 b0 = vlib_get_buffer (vm, bi0);
1782 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1784 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1786 error0 = TCP_ERROR_INVALID_CONNECTION;
1787 next0 = TCP_OUTPUT_NEXT_DROP;
1791 th0 = vlib_buffer_get_current (b0);
1792 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1796 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1797 IP_PROTOCOL_TCP, 1);
1798 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1799 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1805 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1806 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1807 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1808 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1809 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1813 /* Filter out DUPACKs if there are no OOO segments left */
1815 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1817 if (!tcp_session_has_ooo_data (tc0))
1819 error0 = TCP_ERROR_FILTERED_DUPACKS;
1820 next0 = TCP_OUTPUT_NEXT_DROP;
1825 /* Stop DELACK timer and fix flags */
1826 tc0->flags &= ~(TCP_CONN_SNDACK);
1827 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1829 /* If not retransmitting
1830 * 1) update snd_una_max (SYN, SYNACK, FIN)
1831 * 2) If we're not tracking an ACK, start tracking */
1832 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1834 tc0->snd_una_max = tc0->snd_nxt;
1835 if (tc0->rtt_ts == 0)
1837 tc0->rtt_ts = tcp_time_now ();
1838 tc0->rtt_seq = tc0->snd_nxt;
1842 /* Set the retransmit timer if not set already and not
1843 * doing a pure ACK */
1844 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1845 && tc0->snd_nxt != tc0->snd_una)
1847 tcp_retransmit_timer_set (tc0);
1852 /* Make sure we haven't lost route to our peer */
1853 if (PREDICT_FALSE (tc0->last_fib_check
1854 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1857 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1859 tc0->last_fib_check = tc0->snd_opts.tsval;
1863 clib_warning ("lost connection to peer");
1864 tcp_connection_reset (tc0);
1869 /* Use pre-computed dpo to set next node */
1870 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1871 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1874 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1875 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1877 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1879 b0->error = node->errors[error0];
1880 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1882 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1885 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1889 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1891 clib_memcpy (&t0->tcp_connection, tc0,
1892 sizeof (t0->tcp_connection));
1895 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1896 n_left_to_next, bi0, next0);
1899 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1902 return from_frame->n_vectors;
1906 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1907 vlib_frame_t * from_frame)
1909 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1913 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1914 vlib_frame_t * from_frame)
1916 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1920 VLIB_REGISTER_NODE (tcp4_output_node) =
1922 .function = tcp4_output,.name = "tcp4-output",
1923 /* Takes a vector of packets. */
1924 .vector_size = sizeof (u32),
1925 .n_errors = TCP_N_ERROR,
1926 .error_strings = tcp_error_strings,
1927 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1929 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1930 foreach_tcp4_output_next
1933 .format_buffer = format_tcp_header,
1934 .format_trace = format_tcp_tx_trace,
1938 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1941 VLIB_REGISTER_NODE (tcp6_output_node) =
1943 .function = tcp6_output,
1944 .name = "tcp6-output",
1945 /* Takes a vector of packets. */
1946 .vector_size = sizeof (u32),
1947 .n_errors = TCP_N_ERROR,
1948 .error_strings = tcp_error_strings,
1949 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1951 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1952 foreach_tcp6_output_next
1955 .format_buffer = format_tcp_header,
1956 .format_trace = format_tcp_tx_trace,
1960 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1963 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1965 tcp_connection_t *tc;
1967 tc = (tcp_connection_t *) tconn;
1968 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1969 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1971 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1973 tc->rtt_ts = tcp_time_now ();
1974 tc->rtt_seq = tc->snd_nxt;
1976 tcp_trajectory_add_start (b0, 3);
1980 typedef enum _tcp_reset_next
1982 TCP_RESET_NEXT_DROP,
1983 TCP_RESET_NEXT_IP_LOOKUP,
1987 #define foreach_tcp4_reset_next \
1988 _(DROP, "error-drop") \
1989 _(IP_LOOKUP, "ip4-lookup")
1991 #define foreach_tcp6_reset_next \
1992 _(DROP, "error-drop") \
1993 _(IP_LOOKUP, "ip6-lookup")
1996 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
1997 vlib_frame_t * from_frame, u8 is_ip4)
1999 u32 n_left_from, next_index, *from, *to_next;
2000 u32 my_thread_index = vm->thread_index;
2002 from = vlib_frame_vector_args (from_frame);
2003 n_left_from = from_frame->n_vectors;
2005 next_index = node->cached_next_index;
2007 while (n_left_from > 0)
2011 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
2013 while (n_left_from > 0 && n_left_to_next > 0)
2019 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
2026 n_left_to_next -= 1;
2028 b0 = vlib_get_buffer (vm, bi0);
2030 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
2031 my_thread_index, is_ip4))
2033 error0 = TCP_ERROR_LOOKUP_DROPS;
2034 next0 = TCP_RESET_NEXT_DROP;
2038 /* Prepare to send to IP lookup */
2039 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
2040 next0 = TCP_RESET_NEXT_IP_LOOKUP;
2043 b0->error = node->errors[error0];
2044 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
2045 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
2047 th0 = vlib_buffer_get_current (b0);
2049 th0 = ip4_next_header ((ip4_header_t *) th0);
2051 th0 = ip6_next_header ((ip6_header_t *) th0);
2052 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
2053 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
2056 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
2057 n_left_to_next, bi0, next0);
2059 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
2061 return from_frame->n_vectors;
2065 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2066 vlib_frame_t * from_frame)
2068 return tcp46_send_reset_inline (vm, node, from_frame, 1);
2072 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2073 vlib_frame_t * from_frame)
2075 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2079 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2080 .function = tcp4_send_reset,
2081 .name = "tcp4-reset",
2082 .vector_size = sizeof (u32),
2083 .n_errors = TCP_N_ERROR,
2084 .error_strings = tcp_error_strings,
2085 .n_next_nodes = TCP_RESET_N_NEXT,
2087 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2088 foreach_tcp4_reset_next
2091 .format_trace = format_tcp_tx_trace,
2095 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2098 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2099 .function = tcp6_send_reset,
2100 .name = "tcp6-reset",
2101 .vector_size = sizeof (u32),
2102 .n_errors = TCP_N_ERROR,
2103 .error_strings = tcp_error_strings,
2104 .n_next_nodes = TCP_RESET_N_NEXT,
2106 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2107 foreach_tcp6_reset_next
2110 .format_trace = format_tcp_tx_trace,
2114 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2117 * fd.io coding-style-patch-verification: ON
2120 * eval: (c-set-style "gnu")