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,
27 TCP_OUTPUT_NEXT_IP_REWRITE,
28 TCP_OUTPUT_NEXT_IP_ARP,
32 #define foreach_tcp4_output_next \
33 _ (DROP, "error-drop") \
34 _ (IP_LOOKUP, "ip4-lookup") \
35 _ (IP_REWRITE, "ip4-rewrite") \
38 #define foreach_tcp6_output_next \
39 _ (DROP, "error-drop") \
40 _ (IP_LOOKUP, "ip6-lookup") \
41 _ (IP_REWRITE, "ip6-rewrite") \
42 _ (IP_ARP, "ip6-discover-neighbor")
44 static char *tcp_error_strings[] = {
45 #define tcp_error(n,s) s,
46 #include <vnet/tcp/tcp_error.def>
52 tcp_header_t tcp_header;
53 tcp_connection_t tcp_connection;
59 format_tcp_tx_trace (u8 * s, va_list * args)
61 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
62 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
63 tcp_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *);
64 u32 indent = format_get_indent (s);
66 s = format (s, "%U\n%U%U",
67 format_tcp_header, &t->tcp_header, 128,
68 format_white_space, indent,
69 format_tcp_connection, &t->tcp_connection, 1);
75 tcp_window_compute_scale (u32 window)
78 while (wnd_scale < TCP_MAX_WND_SCALE && (window >> wnd_scale) > TCP_WND_MAX)
84 * Update max segment size we're able to process.
86 * The value is constrained by our interface's MTU and IP options. It is
87 * also what we advertise to our peer.
90 tcp_update_rcv_mss (tcp_connection_t * tc)
92 /* TODO find our iface MTU */
93 tc->mss = dummy_mtu - sizeof (tcp_header_t);
97 * TCP's initial window
100 tcp_initial_wnd_unscaled (tcp_connection_t * tc)
102 /* RFC 6928 recommends the value lower. However at the time our connections
103 * are initialized, fifos may not be allocated. Therefore, advertise the
104 * smallest possible unscaled window size and update once fifos are
105 * assigned to the session.
108 tcp_update_rcv_mss (tc);
109 TCP_IW_N_SEGMENTS * tc->mss;
111 return TCP_MIN_RX_FIFO_SIZE;
115 * Compute initial window and scale factor. As per RFC1323, window field in
116 * SYN and SYN-ACK segments is never scaled.
119 tcp_initial_window_to_advertise (tcp_connection_t * tc)
123 /* Initial wnd for SYN. Fifos are not allocated yet.
124 * Use some predefined value. For SYN-ACK we still want the
125 * scale to be computed in the same way */
126 max_fifo = TCP_MAX_RX_FIFO_SIZE;
128 tc->rcv_wscale = tcp_window_compute_scale (max_fifo);
129 tc->rcv_wnd = tcp_initial_wnd_unscaled (tc);
131 return clib_min (tc->rcv_wnd, TCP_WND_MAX);
135 * Compute and return window to advertise, scaled as per RFC1323
138 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
140 if (state < TCP_STATE_ESTABLISHED)
141 return tcp_initial_window_to_advertise (tc);
143 tcp_update_rcv_wnd (tc);
145 if (tc->rcv_wnd == 0)
147 tc->flags |= TCP_CONN_SENT_RCV_WND0;
151 tc->flags &= ~TCP_CONN_SENT_RCV_WND0;
154 return tc->rcv_wnd >> tc->rcv_wscale;
158 tcp_update_rcv_wnd (tcp_connection_t * tc)
161 u32 available_space, max_fifo, wnd;
164 * Figure out how much space we have available
166 available_space = stream_session_max_rx_enqueue (&tc->connection);
167 max_fifo = stream_session_rx_fifo_size (&tc->connection);
169 ASSERT (tc->rcv_opts.mss < max_fifo);
170 if (available_space < tc->rcv_opts.mss && available_space < max_fifo >> 3)
174 * Use the above and what we know about what we've previously advertised
175 * to compute the new window
177 observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las);
178 if (observed_wnd < 0)
181 /* Bad. Thou shalt not shrink */
182 if (available_space < observed_wnd)
185 TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
189 wnd = available_space;
192 /* Make sure we have a multiple of rcv_wscale */
193 if (wnd && tc->rcv_wscale)
195 wnd &= ~(1 << tc->rcv_wscale);
197 wnd = 1 << tc->rcv_wscale;
200 tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
204 * Write TCP options to segment.
207 tcp_options_write (u8 * data, tcp_options_t * opts)
210 u32 buf, seq_len = 4;
212 if (tcp_opts_mss (opts))
214 *data++ = TCP_OPTION_MSS;
215 *data++ = TCP_OPTION_LEN_MSS;
216 buf = clib_host_to_net_u16 (opts->mss);
217 clib_memcpy (data, &buf, sizeof (opts->mss));
218 data += sizeof (opts->mss);
219 opts_len += TCP_OPTION_LEN_MSS;
222 if (tcp_opts_wscale (opts))
224 *data++ = TCP_OPTION_WINDOW_SCALE;
225 *data++ = TCP_OPTION_LEN_WINDOW_SCALE;
226 *data++ = opts->wscale;
227 opts_len += TCP_OPTION_LEN_WINDOW_SCALE;
230 if (tcp_opts_sack_permitted (opts))
232 *data++ = TCP_OPTION_SACK_PERMITTED;
233 *data++ = TCP_OPTION_LEN_SACK_PERMITTED;
234 opts_len += TCP_OPTION_LEN_SACK_PERMITTED;
237 if (tcp_opts_tstamp (opts))
239 *data++ = TCP_OPTION_TIMESTAMP;
240 *data++ = TCP_OPTION_LEN_TIMESTAMP;
241 buf = clib_host_to_net_u32 (opts->tsval);
242 clib_memcpy (data, &buf, sizeof (opts->tsval));
243 data += sizeof (opts->tsval);
244 buf = clib_host_to_net_u32 (opts->tsecr);
245 clib_memcpy (data, &buf, sizeof (opts->tsecr));
246 data += sizeof (opts->tsecr);
247 opts_len += TCP_OPTION_LEN_TIMESTAMP;
250 if (tcp_opts_sack (opts))
253 u32 n_sack_blocks = clib_min (vec_len (opts->sacks),
254 TCP_OPTS_MAX_SACK_BLOCKS);
256 if (n_sack_blocks != 0)
258 *data++ = TCP_OPTION_SACK_BLOCK;
259 *data++ = 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
260 for (i = 0; i < n_sack_blocks; i++)
262 buf = clib_host_to_net_u32 (opts->sacks[i].start);
263 clib_memcpy (data, &buf, seq_len);
265 buf = clib_host_to_net_u32 (opts->sacks[i].end);
266 clib_memcpy (data, &buf, seq_len);
269 opts_len += 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
273 /* Terminate TCP options */
276 *data++ = TCP_OPTION_EOL;
277 opts_len += TCP_OPTION_LEN_EOL;
280 /* Pad with zeroes to a u32 boundary */
283 *data++ = TCP_OPTION_NOOP;
284 opts_len += TCP_OPTION_LEN_NOOP;
290 tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale)
294 opts->flags |= TCP_OPTS_FLAG_MSS;
295 opts->mss = dummy_mtu; /*XXX discover that */
296 len += TCP_OPTION_LEN_MSS;
298 opts->flags |= TCP_OPTS_FLAG_WSCALE;
299 opts->wscale = wnd_scale;
300 len += TCP_OPTION_LEN_WINDOW_SCALE;
302 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
303 opts->tsval = tcp_time_now ();
305 len += TCP_OPTION_LEN_TIMESTAMP;
309 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
310 len += TCP_OPTION_LEN_SACK_PERMITTED;
313 /* Align to needed boundary */
314 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
319 tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
323 opts->flags |= TCP_OPTS_FLAG_MSS;
325 len += TCP_OPTION_LEN_MSS;
327 if (tcp_opts_wscale (&tc->rcv_opts))
329 opts->flags |= TCP_OPTS_FLAG_WSCALE;
330 opts->wscale = tc->rcv_wscale;
331 len += TCP_OPTION_LEN_WINDOW_SCALE;
334 if (tcp_opts_tstamp (&tc->rcv_opts))
336 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
337 opts->tsval = tcp_time_now ();
338 opts->tsecr = tc->tsval_recent;
339 len += TCP_OPTION_LEN_TIMESTAMP;
342 if (tcp_opts_sack_permitted (&tc->rcv_opts))
344 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
345 len += TCP_OPTION_LEN_SACK_PERMITTED;
348 /* Align to needed boundary */
349 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
354 tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
360 if (tcp_opts_tstamp (&tc->rcv_opts))
362 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
363 opts->tsval = tcp_time_now ();
364 opts->tsecr = tc->tsval_recent;
365 len += TCP_OPTION_LEN_TIMESTAMP;
367 if (tcp_opts_sack_permitted (&tc->rcv_opts))
369 if (vec_len (tc->snd_sacks))
371 opts->flags |= TCP_OPTS_FLAG_SACK;
372 opts->sacks = tc->snd_sacks;
373 opts->n_sack_blocks = clib_min (vec_len (tc->snd_sacks),
374 TCP_OPTS_MAX_SACK_BLOCKS);
375 len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks;
379 /* Align to needed boundary */
380 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
385 tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
390 case TCP_STATE_ESTABLISHED:
391 case TCP_STATE_FIN_WAIT_1:
392 return tcp_make_established_options (tc, opts);
393 case TCP_STATE_SYN_RCVD:
394 return tcp_make_synack_options (tc, opts);
395 case TCP_STATE_SYN_SENT:
396 return tcp_make_syn_options (opts, tc->rcv_wscale);
398 clib_warning ("State not handled! %d", state);
404 * Update snd_mss to reflect the effective segment size that we can send
405 * by taking into account all TCP options, including SACKs
408 tcp_update_snd_mss (tcp_connection_t * tc)
410 /* Compute options to be used for connection. These may be reused when
411 * sending data or to compute the effective mss (snd_mss) */
413 tcp_make_options (tc, &tc->snd_opts, TCP_STATE_ESTABLISHED);
415 /* XXX check if MTU has been updated */
416 tc->snd_mss = clib_min (tc->mss, tc->rcv_opts.mss) - tc->snd_opts_len;
417 ASSERT (tc->snd_mss > 0);
421 tcp_init_mss (tcp_connection_t * tc)
423 u16 default_min_mss = 536;
424 tcp_update_rcv_mss (tc);
426 /* TODO cache mss and consider PMTU discovery */
427 tc->snd_mss = clib_min (tc->rcv_opts.mss, tc->mss);
429 if (tc->snd_mss < 45)
431 clib_warning ("snd mss is 0");
432 /* Assume that at least the min default mss works */
433 tc->snd_mss = default_min_mss;
434 tc->rcv_opts.mss = default_min_mss;
437 /* We should have enough space for 40 bytes of options */
438 ASSERT (tc->snd_mss > 45);
440 /* If we use timestamp option, account for it */
441 if (tcp_opts_tstamp (&tc->rcv_opts))
442 tc->snd_mss -= TCP_OPTION_LEN_TIMESTAMP;
446 tcp_alloc_tx_buffers (tcp_main_t * tm, u8 thread_index, u16 * n_bufs,
449 vlib_main_t *vm = vlib_get_main ();
452 ASSERT (wanted > *n_bufs);
453 vec_validate_aligned (tm->tx_buffers[thread_index], wanted - 1,
454 CLIB_CACHE_LINE_BYTES);
455 n_alloc = vlib_buffer_alloc (vm, &tm->tx_buffers[thread_index][*n_bufs],
458 _vec_len (tm->tx_buffers[thread_index]) = *n_bufs;
463 tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx)
465 u32 thread_index = vlib_get_thread_index ();
466 u16 n_bufs = vec_len (tm->tx_buffers[thread_index]);
468 TCP_DBG_BUFFER_ALLOC_MAYBE_FAIL (thread_index);
470 if (PREDICT_FALSE (!n_bufs))
472 if (!tcp_alloc_tx_buffers (tm, thread_index, &n_bufs, VLIB_FRAME_SIZE))
478 *bidx = tm->tx_buffers[thread_index][--n_bufs];
479 _vec_len (tm->tx_buffers[thread_index]) = n_bufs;
484 tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
486 if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
487 vlib_buffer_free_one (vm, b->next_buffer);
488 /* Zero all flags but free list index and trace flag */
489 b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1;
491 b->current_length = 0;
492 b->total_length_not_including_first_buffer = 0;
493 vnet_buffer (b)->tcp.flags = 0;
495 /* Leave enough space for headers */
496 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
500 tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
502 ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
503 b->flags &= VLIB_BUFFER_NON_DEFAULT_FREELIST;
504 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
505 b->total_length_not_including_first_buffer = 0;
507 vnet_buffer (b)->tcp.flags = 0;
508 VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b);
509 /* Leave enough space for headers */
510 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
517 tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
520 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
521 u8 tcp_opts_len, tcp_hdr_opts_len;
525 wnd = tcp_window_to_advertise (tc, state);
527 /* Make and write options */
528 tcp_opts_len = tcp_make_established_options (tc, snd_opts);
529 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
531 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
532 tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
534 tcp_options_write ((u8 *) (th + 1), snd_opts);
535 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
539 * Convert buffer to ACK
542 tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
544 vlib_main_t *vm = vlib_get_main ();
546 tcp_reuse_buffer (vm, b);
547 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
548 TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
549 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
550 tc->rcv_las = tc->rcv_nxt;
554 * Convert buffer to FIN-ACK
557 tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
559 vlib_main_t *vm = vlib_get_main ();
562 tcp_reuse_buffer (vm, b);
564 flags = TCP_FLAG_FIN | TCP_FLAG_ACK;
565 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags);
567 /* Reset flags, make sure ack is sent */
568 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
572 * Convert buffer to SYN
575 tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
577 u8 tcp_hdr_opts_len, tcp_opts_len;
580 tcp_options_t snd_opts;
582 initial_wnd = tcp_initial_window_to_advertise (tc);
584 /* Make and write options */
585 memset (&snd_opts, 0, sizeof (snd_opts));
586 tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale);
587 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
589 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
590 tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
592 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
593 tcp_options_write ((u8 *) (th + 1), &snd_opts);
597 * Convert buffer to SYN-ACK
600 tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
602 vlib_main_t *vm = vlib_get_main ();
603 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
604 u8 tcp_opts_len, tcp_hdr_opts_len;
608 memset (snd_opts, 0, sizeof (*snd_opts));
609 tcp_reuse_buffer (vm, b);
611 initial_wnd = tcp_initial_window_to_advertise (tc);
612 tcp_opts_len = tcp_make_synack_options (tc, snd_opts);
613 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
615 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
616 tc->rcv_nxt, tcp_hdr_opts_len,
617 TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd);
618 tcp_options_write ((u8 *) (th + 1), snd_opts);
620 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
621 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
623 /* Init retransmit timer. Use update instead of set because of
625 tcp_retransmit_timer_force_update (tc);
626 TCP_EVT_DBG (TCP_EVT_SYNACK_SENT, tc);
630 tcp_enqueue_to_ip_lookup_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
631 u8 is_ip4, u32 fib_index, u8 flush)
633 tcp_main_t *tm = vnet_get_tcp_main ();
634 u32 thread_index = vlib_get_thread_index ();
635 u32 *to_next, next_index;
638 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
641 vnet_buffer (b)->sw_if_index[VLIB_TX] = fib_index;
642 vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
644 /* Send to IP lookup */
645 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
646 tcp_trajectory_add_start (b, 1);
648 f = tm->ip_lookup_tx_frames[!is_ip4][thread_index];
651 f = vlib_get_frame_to_node (vm, next_index);
653 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = f;
656 to_next = vlib_frame_vector_args (f);
657 to_next[f->n_vectors] = bi;
659 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
661 vlib_put_frame_to_node (vm, next_index, f);
662 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
667 tcp_enqueue_to_ip_lookup_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
668 u8 is_ip4, u32 fib_index)
670 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, fib_index, 1);
674 tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
675 u8 is_ip4, u32 fib_index)
677 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, fib_index, 0);
681 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
684 tcp_main_t *tm = vnet_get_tcp_main ();
685 u32 thread_index = vlib_get_thread_index ();
686 u32 *to_next, next_index;
689 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
692 /* Decide where to send the packet */
693 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
694 tcp_trajectory_add_start (b, 2);
696 /* Get frame to v4/6 output node */
697 f = tm->tx_frames[!is_ip4][thread_index];
700 f = vlib_get_frame_to_node (vm, next_index);
702 tm->tx_frames[!is_ip4][thread_index] = f;
704 to_next = vlib_frame_vector_args (f);
705 to_next[f->n_vectors] = bi;
707 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
709 vlib_put_frame_to_node (vm, next_index, f);
710 tm->tx_frames[!is_ip4][thread_index] = 0;
715 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
717 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
721 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
724 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
728 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
729 tcp_state_t state, u8 thread_index, u8 is_ip4)
734 ip4_address_t src_ip40, dst_ip40;
735 ip6_address_t src_ip60, dst_ip60;
736 u16 src_port, dst_port;
741 /* Find IP and TCP headers */
742 th0 = tcp_buffer_hdr (b0);
744 /* Save src and dst ip */
747 ih4 = vlib_buffer_get_current (b0);
748 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
749 src_ip40.as_u32 = ih4->src_address.as_u32;
750 dst_ip40.as_u32 = ih4->dst_address.as_u32;
754 ih6 = vlib_buffer_get_current (b0);
755 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
756 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
757 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
760 src_port = th0->src_port;
761 dst_port = th0->dst_port;
763 /* Try to determine what/why we're actually resetting */
764 if (state == TCP_STATE_CLOSED)
769 tmp = clib_net_to_host_u32 (th0->seq_number);
771 /* Got a SYN for no listener. */
772 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
773 ack = clib_host_to_net_u32 (tmp + 1);
778 flags = TCP_FLAG_RST;
779 seq = th0->ack_number;
783 tcp_reuse_buffer (vm, b0);
784 tcp_trajectory_add_start (b0, 4);
785 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
786 sizeof (tcp_header_t), flags, 0);
790 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
792 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
797 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
799 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
807 * Send reset without reusing existing buffer
809 * It extracts connection info out of original packet
812 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
815 u32 bi, sw_if_index, fib_index;
816 tcp_main_t *tm = vnet_get_tcp_main ();
817 vlib_main_t *vm = vlib_get_main ();
818 u8 tcp_hdr_len, flags = 0;
819 tcp_header_t *th, *pkt_th;
821 ip4_header_t *ih4, *pkt_ih4;
822 ip6_header_t *ih6, *pkt_ih6;
823 fib_protocol_t fib_proto;
825 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
828 b = vlib_get_buffer (vm, bi);
829 sw_if_index = vnet_buffer (pkt)->sw_if_index[VLIB_RX];
830 fib_proto = is_ip4 ? FIB_PROTOCOL_IP4 : FIB_PROTOCOL_IP6;
831 fib_index = fib_table_get_index_for_sw_if_index (fib_proto, sw_if_index);
832 tcp_init_buffer (vm, b);
834 /* Make and write options */
835 tcp_hdr_len = sizeof (tcp_header_t);
839 pkt_ih4 = vlib_buffer_get_current (pkt);
840 pkt_th = ip4_next_header (pkt_ih4);
844 pkt_ih6 = vlib_buffer_get_current (pkt);
845 pkt_th = ip6_next_header (pkt_ih6);
848 if (tcp_ack (pkt_th))
850 flags = TCP_FLAG_RST;
851 seq = pkt_th->ack_number;
852 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
856 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
858 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
861 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
862 seq, ack, tcp_hdr_len, flags, 0);
864 /* Swap src and dst ip */
867 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
868 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
869 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
870 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
875 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
877 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
878 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
879 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
883 tcp_enqueue_to_ip_lookup_now (vm, b, bi, is_ip4, fib_index);
884 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
888 * Build and set reset packet for connection
891 tcp_send_reset (tcp_connection_t * tc)
893 vlib_main_t *vm = vlib_get_main ();
894 tcp_main_t *tm = vnet_get_tcp_main ();
898 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
901 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
903 b = vlib_get_buffer (vm, bi);
904 tcp_init_buffer (vm, b);
906 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
907 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
908 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
909 flags = TCP_FLAG_RST;
910 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
911 tc->rcv_nxt, tcp_hdr_opts_len, flags,
913 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
914 ASSERT (opts_write_len == tc->snd_opts_len);
915 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
919 ih4 = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip.ip4,
920 &tc->c_rmt_ip.ip4, IP_PROTOCOL_TCP, 0);
921 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
927 ih6 = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip.ip6,
928 &tc->c_rmt_ip.ip6, IP_PROTOCOL_TCP);
929 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
932 tcp_enqueue_to_ip_lookup_now (vm, b, bi, tc->c_is_ip4, tc->c_fib_index);
933 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
937 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
939 tcp_header_t *th = vlib_buffer_get_current (b);
940 vlib_main_t *vm = vlib_get_main ();
944 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
945 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
946 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
953 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
954 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
955 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
963 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
964 * The packet is not forwarded through tcpx_output to avoid doing lookups
965 * in the half_open pool.
968 tcp_send_syn (tcp_connection_t * tc)
972 tcp_main_t *tm = vnet_get_tcp_main ();
973 vlib_main_t *vm = vlib_get_main ();
976 * Setup retransmit and establish timers before requesting buffer
977 * such that we can return if we've ran out.
979 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
980 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
981 tc->rto * TCP_TO_TIMER_TICK);
983 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
986 b = vlib_get_buffer (vm, bi);
987 tcp_init_buffer (vm, b);
988 tcp_make_syn (tc, b);
990 /* Measure RTT with this */
991 tc->rtt_ts = tcp_time_now ();
992 tc->rtt_seq = tc->snd_nxt;
995 tcp_push_ip_hdr (tm, tc, b);
996 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4, tc->c_fib_index);
997 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
1001 * Flush tx frame populated by retransmits and timer pops
1004 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1006 if (tcp_main.tx_frames[!is_ip4][thread_index])
1009 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
1010 vlib_put_frame_to_node (vm, next_index,
1011 tcp_main.tx_frames[!is_ip4][thread_index]);
1012 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
1017 * Flush ip lookup tx frames populated by timer pops
1020 tcp_flush_frame_to_ip_lookup (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1022 if (tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index])
1025 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
1026 vlib_put_frame_to_node (vm, next_index,
1027 tcp_main.ip_lookup_tx_frames[!is_ip4]
1029 tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
1034 * Flush v4 and v6 tcp and ip-lookup tx frames for thread index
1037 tcp_flush_frames_to_output (u8 thread_index)
1039 vlib_main_t *vm = vlib_get_main ();
1040 tcp_flush_frame_to_output (vm, thread_index, 1);
1041 tcp_flush_frame_to_output (vm, thread_index, 0);
1042 tcp_flush_frame_to_ip_lookup (vm, thread_index, 1);
1043 tcp_flush_frame_to_ip_lookup (vm, thread_index, 0);
1050 tcp_send_fin (tcp_connection_t * tc)
1052 tcp_main_t *tm = vnet_get_tcp_main ();
1053 vlib_main_t *vm = vlib_get_main ();
1058 tcp_retransmit_timer_force_update (tc);
1059 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1061 b = vlib_get_buffer (vm, bi);
1062 tcp_init_buffer (vm, b);
1063 fin_snt = tc->flags & TCP_CONN_FINSNT;
1065 tc->snd_nxt = tc->snd_una;
1066 tcp_make_fin (tc, b);
1067 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
1070 tc->flags |= TCP_CONN_FINSNT;
1071 tc->flags &= ~TCP_CONN_FINPNDG;
1072 /* Account for the FIN */
1073 tc->snd_una_max += 1;
1074 tc->snd_nxt = tc->snd_una_max;
1078 tc->snd_nxt = tc->snd_una_max;
1080 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1084 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1088 case TCP_STATE_ESTABLISHED:
1089 return TCP_FLAG_ACK;
1090 case TCP_STATE_SYN_RCVD:
1091 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1092 case TCP_STATE_SYN_SENT:
1093 return TCP_FLAG_SYN;
1094 case TCP_STATE_LAST_ACK:
1095 case TCP_STATE_FIN_WAIT_1:
1096 if (tc->snd_nxt + 1 < tc->snd_una_max)
1097 return TCP_FLAG_ACK;
1099 return TCP_FLAG_FIN;
1101 clib_warning ("Shouldn't be here!");
1107 * Push TCP header and update connection variables
1110 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1111 tcp_state_t next_state, u8 compute_opts)
1113 u32 advertise_wnd, data_len;
1114 u8 tcp_hdr_opts_len, opts_write_len, flags;
1117 data_len = b->current_length + b->total_length_not_including_first_buffer;
1118 ASSERT (!b->total_length_not_including_first_buffer
1119 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1120 vnet_buffer (b)->tcp.flags = 0;
1123 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1125 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1126 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1127 flags = tcp_make_state_flags (tc, next_state);
1129 /* Push header and options */
1130 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1131 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1133 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1135 ASSERT (opts_write_len == tc->snd_opts_len);
1136 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1139 * Update connection variables
1142 tc->snd_nxt += data_len;
1143 tc->rcv_las = tc->rcv_nxt;
1145 /* TODO this is updated in output as well ... */
1146 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1148 tc->snd_una_max = tc->snd_nxt;
1149 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1152 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1156 tcp_send_ack (tcp_connection_t * tc)
1158 tcp_main_t *tm = vnet_get_tcp_main ();
1159 vlib_main_t *vm = vlib_get_main ();
1165 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1167 b = vlib_get_buffer (vm, bi);
1168 tcp_init_buffer (vm, b);
1170 /* Fill in the ACK */
1171 tcp_make_ack (tc, b);
1172 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1176 * Delayed ack timer handler
1178 * Sends delayed ACK when timer expires
1181 tcp_timer_delack_handler (u32 index)
1183 u32 thread_index = vlib_get_thread_index ();
1184 tcp_connection_t *tc;
1186 tc = tcp_connection_get (index, thread_index);
1187 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1192 * Build a retransmit segment
1194 * @return the number of bytes in the segment or 0 if there's nothing to
1198 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1199 u32 max_deq_bytes, vlib_buffer_t ** b)
1201 tcp_main_t *tm = vnet_get_tcp_main ();
1202 vlib_main_t *vm = vlib_get_main ();
1204 u32 start, bi, available_bytes, seg_size;
1207 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1208 ASSERT (max_deq_bytes != 0);
1211 * Make sure we can retransmit something
1213 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1214 ASSERT (available_bytes >= offset);
1215 available_bytes -= offset;
1216 if (!available_bytes)
1218 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1219 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1221 /* Start is beyond snd_congestion */
1222 start = tc->snd_una + offset;
1223 if (seq_geq (start, tc->snd_congestion))
1226 /* Don't overshoot snd_congestion */
1227 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1229 max_deq_bytes = tc->snd_congestion - start;
1230 if (max_deq_bytes == 0)
1234 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1239 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1242 * Allocate and fill in buffer(s)
1245 /* Easy case, buffer size greater than mss */
1246 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1248 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1250 *b = vlib_get_buffer (vm, bi);
1251 data = tcp_init_buffer (vm, *b);
1252 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1254 ASSERT (n_bytes == max_deq_bytes);
1255 b[0]->current_length = n_bytes;
1256 tcp_push_hdr_i (tc, *b, tc->state, 0);
1258 /* Split mss into multiple buffers */
1261 u32 chain_bi = ~0, n_bufs_per_seg;
1262 u32 thread_index = vlib_get_thread_index ();
1263 u16 n_peeked, len_to_deq, available_bufs;
1264 vlib_buffer_t *chain_b, *prev_b;
1267 /* Make sure we have enough buffers */
1268 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1269 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1270 if (n_bufs_per_seg > available_bufs)
1272 tcp_alloc_tx_buffers (tm, thread_index, &available_bufs,
1275 if (n_bufs_per_seg > available_bufs)
1282 tcp_get_free_buffer_index (tm, &bi);
1283 ASSERT (bi != (u32) ~ 0);
1284 *b = vlib_get_buffer (vm, bi);
1285 data = tcp_init_buffer (vm, *b);
1286 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1287 tm->bytes_per_buffer -
1289 b[0]->current_length = n_bytes;
1290 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1291 b[0]->total_length_not_including_first_buffer = 0;
1292 max_deq_bytes -= n_bytes;
1295 for (i = 1; i < n_bufs_per_seg; i++)
1298 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1299 tcp_get_free_buffer_index (tm, &chain_bi);
1300 ASSERT (chain_bi != (u32) ~ 0);
1301 chain_b = vlib_get_buffer (vm, chain_bi);
1302 chain_b->current_data = 0;
1303 data = vlib_buffer_get_current (chain_b);
1304 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1305 offset + n_bytes, len_to_deq);
1306 ASSERT (n_peeked == len_to_deq);
1307 n_bytes += n_peeked;
1308 chain_b->current_length = n_peeked;
1309 chain_b->next_buffer = 0;
1311 /* update previous buffer */
1312 prev_b->next_buffer = chain_bi;
1313 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1315 max_deq_bytes -= n_peeked;
1316 b[0]->total_length_not_including_first_buffer += n_peeked;
1319 tcp_push_hdr_i (tc, *b, tc->state, 0);
1322 ASSERT (n_bytes > 0);
1323 ASSERT (((*b)->current_data + (*b)->current_length) <=
1324 tm->bytes_per_buffer);
1326 if (tcp_in_fastrecovery (tc))
1327 tc->snd_rxt_bytes += n_bytes;
1330 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1335 * Reset congestion control, switch cwnd to loss window and try again.
1338 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1340 tc->prev_ssthresh = tc->ssthresh;
1341 tc->prev_cwnd = tc->cwnd;
1343 /* Cleanly recover cc (also clears up fast retransmit) */
1344 if (tcp_in_fastrecovery (tc))
1345 tcp_cc_fastrecovery_exit (tc);
1347 /* Start again from the beginning */
1348 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1349 tc->cwnd = tcp_loss_wnd (tc);
1350 tc->snd_congestion = tc->snd_una_max;
1352 tcp_recovery_on (tc);
1356 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1358 tcp_main_t *tm = vnet_get_tcp_main ();
1359 vlib_main_t *vm = vlib_get_main ();
1360 u32 thread_index = vlib_get_thread_index ();
1361 tcp_connection_t *tc;
1362 vlib_buffer_t *b = 0;
1367 tc = tcp_half_open_connection_get (index);
1368 /* Note: the connection may have transitioned to ESTABLISHED... */
1369 if (PREDICT_FALSE (tc == 0))
1371 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1375 tc = tcp_connection_get (index, thread_index);
1376 /* Note: the connection may have been closed and pool_put */
1377 if (PREDICT_FALSE (tc == 0))
1379 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1382 if (tc->state >= TCP_STATE_ESTABLISHED)
1384 /* Lost FIN, retransmit and return */
1385 if (tcp_is_lost_fin (tc))
1389 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1393 /* Shouldn't be here */
1394 if (tc->snd_una == tc->snd_una_max)
1396 tcp_recovery_off (tc);
1400 /* We're not in recovery so make sure rto_boff is 0 */
1401 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1404 tcp_update_rto (tc);
1407 /* Increment RTO backoff (also equal to number of retries) and go back
1408 * to first un-acked byte */
1411 /* First retransmit timeout */
1412 if (tc->rto_boff == 1)
1413 tcp_rtx_timeout_cc (tc);
1415 tc->snd_nxt = tc->snd_una;
1416 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1418 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1420 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1421 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1423 /* TODO be less aggressive about this */
1424 scoreboard_clear (&tc->sack_sb);
1428 tcp_retransmit_timer_set (tc);
1432 bi = vlib_get_buffer_index (vm, b);
1434 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1435 if (tc->rto_boff == 1)
1436 tc->snd_rxt_ts = tcp_time_now ();
1438 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1439 tcp_retransmit_timer_update (tc);
1441 /* Retransmit for SYN */
1442 else if (tc->state == TCP_STATE_SYN_SENT)
1444 /* Half-open connection actually moved to established but we were
1445 * waiting for syn retransmit to pop to call cleanup from the right
1447 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1449 if (tcp_half_open_connection_cleanup (tc))
1451 clib_warning ("could not remove half-open connection");
1457 /* Try without increasing RTO a number of times. If this fails,
1458 * start growing RTO exponentially */
1460 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1461 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1463 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
1464 tc->rto * TCP_TO_TIMER_TICK);
1466 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1469 b = vlib_get_buffer (vm, bi);
1470 tcp_init_buffer (vm, b);
1471 tcp_make_syn (tc, b);
1474 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1476 /* This goes straight to ipx_lookup. Retransmit timer set already */
1477 tcp_push_ip_hdr (tm, tc, b);
1478 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4, tc->c_fib_index);
1480 /* Retransmit SYN-ACK */
1481 else if (tc->state == TCP_STATE_SYN_RCVD)
1484 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1485 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1488 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1490 tcp_retransmit_timer_force_update (tc);
1494 b = vlib_get_buffer (vm, bi);
1495 tcp_init_buffer (vm, b);
1496 tcp_make_synack (tc, b);
1497 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1499 /* Retransmit timer already updated, just enqueue to output */
1500 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1504 ASSERT (tc->state == TCP_STATE_CLOSED);
1510 tcp_timer_retransmit_handler (u32 index)
1512 tcp_timer_retransmit_handler_i (index, 0);
1516 tcp_timer_retransmit_syn_handler (u32 index)
1518 tcp_timer_retransmit_handler_i (index, 1);
1522 * Got 0 snd_wnd from peer, try to do something about it.
1526 tcp_timer_persist_handler (u32 index)
1528 tcp_main_t *tm = vnet_get_tcp_main ();
1529 vlib_main_t *vm = vlib_get_main ();
1530 u32 thread_index = vlib_get_thread_index ();
1531 tcp_connection_t *tc;
1533 u32 bi, max_snd_bytes, available_bytes, offset;
1537 tc = tcp_connection_get_if_valid (index, thread_index);
1542 /* Make sure timer handle is set to invalid */
1543 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1545 /* Problem already solved or worse */
1546 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1547 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1550 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1551 offset = tc->snd_una_max - tc->snd_una;
1553 /* Reprogram persist if no new bytes available to send. We may have data
1555 if (!available_bytes)
1557 tcp_persist_timer_set (tc);
1561 if (available_bytes <= offset)
1563 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1567 /* Increment RTO backoff */
1569 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1572 * Try to force the first unsent segment (or buffer)
1574 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1576 b = vlib_get_buffer (vm, bi);
1577 data = tcp_init_buffer (vm, b);
1579 tcp_validate_txf_size (tc, offset);
1580 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1581 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1582 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1584 b->current_length = n_bytes;
1585 ASSERT (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)
1586 || tc->snd_nxt == tc->snd_una_max
1587 || tc->rto_boff > 1));
1589 tcp_push_hdr_i (tc, b, tc->state, 0);
1590 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1592 /* Just sent new data, enable retransmit */
1593 tcp_retransmit_timer_update (tc);
1597 * Retransmit first unacked segment
1600 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1602 vlib_main_t *vm = vlib_get_main ();
1604 u32 bi, old_snd_nxt, n_bytes;
1606 old_snd_nxt = tc->snd_nxt;
1607 tc->snd_nxt = tc->snd_una;
1609 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1610 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1613 bi = vlib_get_buffer_index (vm, b);
1614 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1616 tc->snd_nxt = old_snd_nxt;
1620 * Do fast retransmit with SACKs
1623 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1625 vlib_main_t *vm = vlib_get_main ();
1626 u32 n_written = 0, offset, max_bytes;
1627 vlib_buffer_t *b = 0;
1628 sack_scoreboard_hole_t *hole;
1629 sack_scoreboard_t *sb;
1630 u32 bi, old_snd_nxt;
1632 u8 snd_limited = 0, can_rescue = 0;
1634 ASSERT (tcp_in_fastrecovery (tc));
1635 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1637 old_snd_nxt = tc->snd_nxt;
1639 snd_space = tcp_available_snd_space (tc);
1641 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1642 while (hole && snd_space > 0)
1644 hole = scoreboard_next_rxt_hole (sb, hole,
1645 tcp_fastrecovery_sent_1_smss (tc),
1646 &can_rescue, &snd_limited);
1649 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1650 || seq_gt (sb->rescue_rxt,
1651 tc->snd_congestion)))
1654 /* If rescue rxt undefined or less than snd_una then one segment of
1655 * up to SMSS octets that MUST include the highest outstanding
1656 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1657 * RecoveryPoint. HighRxt MUST NOT be updated.
1659 max_bytes = clib_min (tc->snd_mss,
1660 tc->snd_congestion - tc->snd_una);
1661 max_bytes = clib_min (max_bytes, snd_space);
1662 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1663 sb->rescue_rxt = tc->snd_congestion;
1664 tc->snd_nxt = tc->snd_una + offset;
1665 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1670 bi = vlib_get_buffer_index (vm, b);
1671 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1675 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1676 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1679 offset = sb->high_rxt - tc->snd_una;
1680 tc->snd_nxt = sb->high_rxt;
1681 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1683 /* Nothing left to retransmit */
1687 bi = vlib_get_buffer_index (vm, b);
1688 sb->high_rxt += n_written;
1689 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1690 ASSERT (n_written <= snd_space);
1691 snd_space -= n_written;
1695 /* If window allows, send 1 SMSS of new data */
1696 tc->snd_nxt = old_snd_nxt;
1700 * Fast retransmit without SACK info
1703 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1705 vlib_main_t *vm = vlib_get_main ();
1706 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1710 ASSERT (tcp_in_fastrecovery (tc));
1711 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1713 /* Start resending from first un-acked segment */
1714 old_snd_nxt = tc->snd_nxt;
1715 tc->snd_nxt = tc->snd_una;
1716 snd_space = tcp_available_snd_space (tc);
1718 while (snd_space > 0)
1720 offset += n_written;
1721 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1723 /* Nothing left to retransmit */
1727 bi = vlib_get_buffer_index (vm, b);
1728 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1729 snd_space -= n_written;
1732 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1733 tc->snd_nxt = old_snd_nxt;
1737 * Do fast retransmit
1740 tcp_fast_retransmit (tcp_connection_t * tc)
1742 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1743 && scoreboard_first_hole (&tc->sack_sb))
1744 tcp_fast_retransmit_sack (tc);
1746 tcp_fast_retransmit_no_sack (tc);
1750 tcp_session_has_ooo_data (tcp_connection_t * tc)
1752 stream_session_t *s = session_get (tc->c_s_index, tc->c_thread_index);
1753 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1758 fib_protocol_t nh_proto;
1759 vnet_link_t link_type;
1762 } tcp_adj_add_args_t;
1765 tcp_output_add_adj (tcp_adj_add_args_t * args)
1767 adj_nbr_add_or_lock (args->nh_proto, args->link_type, &args->ip,
1772 tcp_output_handle_link_local (tcp_connection_t * tc0, vlib_buffer_t * b0,
1773 u32 * next0, u32 * error0)
1775 ip_adjacency_t *adj;
1778 ai = adj_nbr_find (FIB_PROTOCOL_IP6, VNET_LINK_IP6, &tc0->c_rmt_ip,
1780 if (ai == ADJ_INDEX_INVALID)
1782 tcp_adj_add_args_t args = {
1783 .nh_proto = FIB_PROTOCOL_IP6,
1784 .link_type = VNET_LINK_IP6,
1785 .ip = tc0->c_rmt_ip,
1786 .sw_if_index = tc0->sw_if_index
1788 vlib_rpc_call_main_thread (tcp_output_add_adj, (u8 *) & args,
1790 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1791 *next0 = TCP_OUTPUT_NEXT_DROP;
1792 *error0 = TCP_ERROR_LINK_LOCAL_RW;
1797 if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE)
1798 *next0 = TCP_OUTPUT_NEXT_IP_REWRITE;
1799 else if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP)
1800 *next0 = TCP_OUTPUT_NEXT_IP_ARP;
1804 tcp46_output_inline (vlib_main_t * vm,
1805 vlib_node_runtime_t * node,
1806 vlib_frame_t * from_frame, int is_ip4)
1808 u32 n_left_from, next_index, *from, *to_next;
1809 u32 my_thread_index = vm->thread_index;
1811 from = vlib_frame_vector_args (from_frame);
1812 n_left_from = from_frame->n_vectors;
1813 next_index = node->cached_next_index;
1814 tcp_set_time_now (my_thread_index);
1816 while (n_left_from > 0)
1820 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1822 while (n_left_from > 0 && n_left_to_next > 0)
1826 tcp_connection_t *tc0;
1828 tcp_header_t *th0 = 0;
1829 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1831 if (n_left_from > 1)
1834 pb = vlib_get_buffer (vm, from[1]);
1835 vlib_prefetch_buffer_header (pb, STORE);
1836 CLIB_PREFETCH (pb->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
1844 n_left_to_next -= 1;
1846 b0 = vlib_get_buffer (vm, bi0);
1847 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1849 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1851 error0 = TCP_ERROR_INVALID_CONNECTION;
1852 next0 = TCP_OUTPUT_NEXT_DROP;
1856 th0 = vlib_buffer_get_current (b0);
1857 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1858 vnet_buffer (b0)->sw_if_index[VLIB_TX] = tc0->c_fib_index;
1859 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1863 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1864 IP_PROTOCOL_TCP, 1);
1865 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1866 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1872 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1873 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1874 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1875 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1876 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1880 (ip6_address_is_link_local_unicast (&tc0->c_rmt_ip6)))
1881 tcp_output_handle_link_local (tc0, b0, &next0, &error0);
1884 /* Filter out DUPACKs if there are no OOO segments left */
1886 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1888 /* N.B. Should not filter burst of dupacks. Two issues:
1889 * 1) dupacks open cwnd on remote peer when congested
1890 * 2) acks leaving should have the latest rcv_wnd since the
1891 * burst may have eaten up all of it, so only the old ones
1892 * could be filtered.
1894 if (!tcp_session_has_ooo_data (tc0))
1896 error0 = TCP_ERROR_FILTERED_DUPACKS;
1897 next0 = TCP_OUTPUT_NEXT_DROP;
1902 /* Stop DELACK timer and fix flags */
1903 tc0->flags &= ~(TCP_CONN_SNDACK);
1904 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1906 /* If not retransmitting
1907 * 1) update snd_una_max (SYN, SYNACK, FIN)
1908 * 2) If we're not tracking an ACK, start tracking */
1909 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1911 tc0->snd_una_max = tc0->snd_nxt;
1912 if (tc0->rtt_ts == 0)
1914 tc0->rtt_ts = tcp_time_now ();
1915 tc0->rtt_seq = tc0->snd_nxt;
1919 /* Set the retransmit timer if not set already and not
1920 * doing a pure ACK */
1921 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1922 && tc0->snd_nxt != tc0->snd_una)
1924 tcp_retransmit_timer_set (tc0);
1929 /* Make sure we haven't lost route to our peer */
1930 if (PREDICT_FALSE (tc0->last_fib_check
1931 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1934 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1936 tc0->last_fib_check = tc0->snd_opts.tsval;
1940 clib_warning ("lost connection to peer");
1941 tcp_connection_reset (tc0);
1946 /* Use pre-computed dpo to set next node */
1947 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1948 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1952 b0->error = node->errors[error0];
1953 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1955 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1958 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1962 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1964 clib_memcpy (&t0->tcp_connection, tc0,
1965 sizeof (t0->tcp_connection));
1968 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1969 n_left_to_next, bi0, next0);
1972 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1975 return from_frame->n_vectors;
1979 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1980 vlib_frame_t * from_frame)
1982 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1986 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1987 vlib_frame_t * from_frame)
1989 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1993 VLIB_REGISTER_NODE (tcp4_output_node) =
1995 .function = tcp4_output,.name = "tcp4-output",
1996 /* Takes a vector of packets. */
1997 .vector_size = sizeof (u32),
1998 .n_errors = TCP_N_ERROR,
1999 .error_strings = tcp_error_strings,
2000 .n_next_nodes = TCP_OUTPUT_N_NEXT,
2002 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
2003 foreach_tcp4_output_next
2006 .format_buffer = format_tcp_header,
2007 .format_trace = format_tcp_tx_trace,
2011 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
2014 VLIB_REGISTER_NODE (tcp6_output_node) =
2016 .function = tcp6_output,
2017 .name = "tcp6-output",
2018 /* Takes a vector of packets. */
2019 .vector_size = sizeof (u32),
2020 .n_errors = TCP_N_ERROR,
2021 .error_strings = tcp_error_strings,
2022 .n_next_nodes = TCP_OUTPUT_N_NEXT,
2024 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
2025 foreach_tcp6_output_next
2028 .format_buffer = format_tcp_header,
2029 .format_trace = format_tcp_tx_trace,
2033 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
2036 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
2038 tcp_connection_t *tc;
2040 tc = (tcp_connection_t *) tconn;
2041 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
2042 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
2044 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
2046 tc->rtt_ts = tcp_time_now ();
2047 tc->rtt_seq = tc->snd_nxt;
2049 tcp_trajectory_add_start (b, 3);
2053 typedef enum _tcp_reset_next
2055 TCP_RESET_NEXT_DROP,
2056 TCP_RESET_NEXT_IP_LOOKUP,
2060 #define foreach_tcp4_reset_next \
2061 _(DROP, "error-drop") \
2062 _(IP_LOOKUP, "ip4-lookup")
2064 #define foreach_tcp6_reset_next \
2065 _(DROP, "error-drop") \
2066 _(IP_LOOKUP, "ip6-lookup")
2069 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
2070 vlib_frame_t * from_frame, u8 is_ip4)
2072 u32 n_left_from, next_index, *from, *to_next;
2073 u32 my_thread_index = vm->thread_index;
2075 from = vlib_frame_vector_args (from_frame);
2076 n_left_from = from_frame->n_vectors;
2078 next_index = node->cached_next_index;
2080 while (n_left_from > 0)
2084 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
2086 while (n_left_from > 0 && n_left_to_next > 0)
2092 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
2099 n_left_to_next -= 1;
2101 b0 = vlib_get_buffer (vm, bi0);
2103 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
2104 my_thread_index, is_ip4))
2106 error0 = TCP_ERROR_LOOKUP_DROPS;
2107 next0 = TCP_RESET_NEXT_DROP;
2111 /* Prepare to send to IP lookup */
2112 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
2113 next0 = TCP_RESET_NEXT_IP_LOOKUP;
2116 b0->error = node->errors[error0];
2117 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
2118 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
2120 th0 = vlib_buffer_get_current (b0);
2122 th0 = ip4_next_header ((ip4_header_t *) th0);
2124 th0 = ip6_next_header ((ip6_header_t *) th0);
2125 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
2126 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
2129 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
2130 n_left_to_next, bi0, next0);
2132 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
2134 return from_frame->n_vectors;
2138 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2139 vlib_frame_t * from_frame)
2141 return tcp46_send_reset_inline (vm, node, from_frame, 1);
2145 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2146 vlib_frame_t * from_frame)
2148 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2152 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2153 .function = tcp4_send_reset,
2154 .name = "tcp4-reset",
2155 .vector_size = sizeof (u32),
2156 .n_errors = TCP_N_ERROR,
2157 .error_strings = tcp_error_strings,
2158 .n_next_nodes = TCP_RESET_N_NEXT,
2160 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2161 foreach_tcp4_reset_next
2164 .format_trace = format_tcp_tx_trace,
2168 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2171 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2172 .function = tcp6_send_reset,
2173 .name = "tcp6-reset",
2174 .vector_size = sizeof (u32),
2175 .n_errors = TCP_N_ERROR,
2176 .error_strings = tcp_error_strings,
2177 .n_next_nodes = TCP_RESET_N_NEXT,
2179 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2180 foreach_tcp6_reset_next
2183 .format_trace = format_tcp_tx_trace,
2187 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2190 * fd.io coding-style-patch-verification: ON
2193 * eval: (c-set-style "gnu")