2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #include <vnet/tcp/tcp.h>
17 #include <vnet/lisp-cp/packets.h>
20 vlib_node_registration_t tcp4_output_node;
21 vlib_node_registration_t tcp6_output_node;
23 typedef enum _tcp_output_next
26 TCP_OUTPUT_NEXT_IP_LOOKUP,
30 #define foreach_tcp4_output_next \
31 _ (DROP, "error-drop") \
32 _ (IP_LOOKUP, "ip4-lookup")
34 #define foreach_tcp6_output_next \
35 _ (DROP, "error-drop") \
36 _ (IP_LOOKUP, "ip6-lookup")
38 static char *tcp_error_strings[] = {
39 #define tcp_error(n,s) s,
40 #include <vnet/tcp/tcp_error.def>
46 tcp_header_t tcp_header;
47 tcp_connection_t tcp_connection;
53 format_tcp_tx_trace (u8 * s, va_list * args)
55 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
56 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
57 tcp_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *);
58 uword indent = format_get_indent (s);
60 s = format (s, "%U\n%U%U",
61 format_tcp_header, &t->tcp_header, 128,
62 format_white_space, indent,
63 format_tcp_connection, &t->tcp_connection, 1);
69 tcp_window_compute_scale (u32 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 ();
466 if (PREDICT_FALSE (vec_len (tm->tx_buffers[thread_index]) == 0))
468 if (tcp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE))
471 my_tx_buffers = tm->tx_buffers[thread_index];
472 *bidx = my_tx_buffers[vec_len (my_tx_buffers) - 1];
473 _vec_len (my_tx_buffers) -= 1;
478 tcp_return_buffer (tcp_main_t * tm)
480 _vec_len (tm->tx_buffers[vlib_get_thread_index ()]) += 1;
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_FREE_LIST_INDEX_MASK;
504 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
505 b->total_length_not_including_first_buffer = 0;
506 vnet_buffer (b)->tcp.flags = 0;
508 /* Leave enough space for headers */
509 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
516 tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
519 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
520 u8 tcp_opts_len, tcp_hdr_opts_len;
524 wnd = tcp_window_to_advertise (tc, state);
526 /* Make and write options */
527 tcp_opts_len = tcp_make_established_options (tc, snd_opts);
528 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
530 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
531 tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
533 tcp_options_write ((u8 *) (th + 1), snd_opts);
534 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
538 * Convert buffer to ACK
541 tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
543 vlib_main_t *vm = vlib_get_main ();
545 tcp_reuse_buffer (vm, b);
546 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
547 TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
548 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
549 tc->rcv_las = tc->rcv_nxt;
553 * Convert buffer to FIN-ACK
556 tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
558 vlib_main_t *vm = vlib_get_main ();
561 tcp_reuse_buffer (vm, b);
563 flags = TCP_FLAG_FIN | TCP_FLAG_ACK;
564 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags);
566 /* Reset flags, make sure ack is sent */
567 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
571 * Convert buffer to SYN
574 tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
576 u8 tcp_hdr_opts_len, tcp_opts_len;
579 tcp_options_t snd_opts;
581 initial_wnd = tcp_initial_window_to_advertise (tc);
583 /* Make and write options */
584 memset (&snd_opts, 0, sizeof (snd_opts));
585 tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale);
586 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
588 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
589 tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
591 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
592 tcp_options_write ((u8 *) (th + 1), &snd_opts);
594 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
595 tc->rto * TCP_TO_TIMER_TICK);
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 if (VLIB_BUFFER_TRACE_TRAJECTORY > 0)
651 b->pre_data[1] = next_index;
654 f = tm->ip_lookup_tx_frames[!is_ip4][thread_index];
657 f = vlib_get_frame_to_node (vm, next_index);
659 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = f;
662 to_next = vlib_frame_vector_args (f);
663 to_next[f->n_vectors] = bi;
665 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
667 vlib_put_frame_to_node (vm, next_index, f);
668 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
673 tcp_enqueue_to_ip_lookup_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
676 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, 1);
680 tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
683 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, 0);
687 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
690 tcp_main_t *tm = vnet_get_tcp_main ();
691 u32 thread_index = vlib_get_thread_index ();
692 u32 *to_next, next_index;
695 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
698 /* Decide where to send the packet */
699 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
700 if (VLIB_BUFFER_TRACE_TRAJECTORY > 0)
703 b->pre_data[1] = next_index;
706 /* Get frame to v4/6 output node */
707 f = tm->tx_frames[!is_ip4][thread_index];
710 f = vlib_get_frame_to_node (vm, next_index);
712 tm->tx_frames[!is_ip4][thread_index] = f;
714 to_next = vlib_frame_vector_args (f);
715 to_next[f->n_vectors] = bi;
717 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
719 vlib_put_frame_to_node (vm, next_index, f);
720 tm->tx_frames[!is_ip4][thread_index] = 0;
725 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
727 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
731 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
734 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
738 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
739 tcp_state_t state, u8 thread_index, u8 is_ip4)
744 ip4_address_t src_ip40, dst_ip40;
745 ip6_address_t src_ip60, dst_ip60;
746 u16 src_port, dst_port;
751 /* Find IP and TCP headers */
752 th0 = tcp_buffer_hdr (b0);
754 /* Save src and dst ip */
757 ih4 = vlib_buffer_get_current (b0);
758 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
759 src_ip40.as_u32 = ih4->src_address.as_u32;
760 dst_ip40.as_u32 = ih4->dst_address.as_u32;
764 ih6 = vlib_buffer_get_current (b0);
765 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
766 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
767 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
770 src_port = th0->src_port;
771 dst_port = th0->dst_port;
773 /* Try to determine what/why we're actually resetting */
774 if (state == TCP_STATE_CLOSED)
779 tmp = clib_net_to_host_u32 (th0->seq_number);
781 /* Got a SYN for no listener. */
782 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
783 ack = clib_host_to_net_u32 (tmp + 1);
788 flags = TCP_FLAG_RST;
789 seq = th0->ack_number;
793 tcp_reuse_buffer (vm, b0);
794 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
795 sizeof (tcp_header_t), flags, 0);
799 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
801 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
806 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
808 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
816 * Send reset without reusing existing buffer
818 * It extracts connection info out of original packet
821 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
825 tcp_main_t *tm = vnet_get_tcp_main ();
826 vlib_main_t *vm = vlib_get_main ();
827 u8 tcp_hdr_len, flags = 0;
828 tcp_header_t *th, *pkt_th;
830 ip4_header_t *ih4, *pkt_ih4;
831 ip6_header_t *ih6, *pkt_ih6;
833 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
836 b = vlib_get_buffer (vm, bi);
837 tcp_init_buffer (vm, b);
839 /* Make and write options */
840 tcp_hdr_len = sizeof (tcp_header_t);
844 pkt_ih4 = vlib_buffer_get_current (pkt);
845 pkt_th = ip4_next_header (pkt_ih4);
849 pkt_ih6 = vlib_buffer_get_current (pkt);
850 pkt_th = ip6_next_header (pkt_ih6);
853 if (tcp_ack (pkt_th))
855 flags = TCP_FLAG_RST;
856 seq = pkt_th->ack_number;
857 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
861 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
863 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
866 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
867 seq, ack, tcp_hdr_len, flags, 0);
869 /* Swap src and dst ip */
872 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
873 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
874 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
875 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
880 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
882 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
883 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
884 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
888 tcp_enqueue_to_ip_lookup_now (vm, b, bi, is_ip4);
889 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
893 * Build and set reset packet for connection
896 tcp_send_reset (tcp_connection_t * tc)
898 vlib_main_t *vm = vlib_get_main ();
899 tcp_main_t *tm = vnet_get_tcp_main ();
903 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
906 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
908 b = vlib_get_buffer (vm, bi);
909 tcp_init_buffer (vm, b);
911 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
912 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
913 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
914 flags = TCP_FLAG_RST;
915 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
916 tc->rcv_nxt, tcp_hdr_opts_len, flags,
918 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
919 ASSERT (opts_write_len == tc->snd_opts_len);
920 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
921 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
925 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
927 tcp_header_t *th = vlib_buffer_get_current (b);
928 vlib_main_t *vm = vlib_get_main ();
932 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
933 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
934 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
941 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
942 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
943 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
951 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
952 * The packet is not forwarded through tcpx_output to avoid doing lookups
953 * in the half_open pool.
956 tcp_send_syn (tcp_connection_t * tc)
960 tcp_main_t *tm = vnet_get_tcp_main ();
961 vlib_main_t *vm = vlib_get_main ();
963 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
966 b = vlib_get_buffer (vm, bi);
967 tcp_init_buffer (vm, b);
968 tcp_make_syn (tc, b);
970 /* Measure RTT with this */
971 tc->rtt_ts = tcp_time_now ();
972 tc->rtt_seq = tc->snd_nxt;
975 /* Set the connection establishment timer */
976 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
978 tcp_push_ip_hdr (tm, tc, b);
979 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
980 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
984 * Flush tx frame populated by retransmits and timer pops
987 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
989 if (tcp_main.tx_frames[!is_ip4][thread_index])
992 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
993 vlib_put_frame_to_node (vm, next_index,
994 tcp_main.tx_frames[!is_ip4][thread_index]);
995 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
1000 * Flush ip lookup tx frames populated by timer pops
1003 tcp_flush_frame_to_ip_lookup (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1005 if (tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index])
1008 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
1009 vlib_put_frame_to_node (vm, next_index,
1010 tcp_main.ip_lookup_tx_frames[!is_ip4]
1012 tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
1017 * Flush v4 and v6 tcp and ip-lookup tx frames for thread index
1020 tcp_flush_frames_to_output (u8 thread_index)
1022 vlib_main_t *vm = vlib_get_main ();
1023 tcp_flush_frame_to_output (vm, thread_index, 1);
1024 tcp_flush_frame_to_output (vm, thread_index, 0);
1025 tcp_flush_frame_to_ip_lookup (vm, thread_index, 1);
1026 tcp_flush_frame_to_ip_lookup (vm, thread_index, 0);
1033 tcp_send_fin (tcp_connection_t * tc)
1035 tcp_main_t *tm = vnet_get_tcp_main ();
1036 vlib_main_t *vm = vlib_get_main ();
1042 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1044 b = vlib_get_buffer (vm, bi);
1045 fin_snt = tc->flags & TCP_CONN_FINSNT;
1047 tc->snd_nxt = tc->snd_una;
1048 tcp_make_fin (tc, b);
1049 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
1052 tc->flags |= TCP_CONN_FINSNT;
1053 tc->flags &= ~TCP_CONN_FINPNDG;
1054 /* Account for the FIN */
1055 tc->snd_una_max += 1;
1056 tc->snd_nxt = tc->snd_una_max;
1058 tcp_retransmit_timer_force_update (tc);
1059 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1063 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1067 case TCP_STATE_ESTABLISHED:
1068 return TCP_FLAG_ACK;
1069 case TCP_STATE_SYN_RCVD:
1070 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1071 case TCP_STATE_SYN_SENT:
1072 return TCP_FLAG_SYN;
1073 case TCP_STATE_LAST_ACK:
1074 case TCP_STATE_FIN_WAIT_1:
1075 if (tc->snd_nxt + 1 < tc->snd_una_max)
1076 return TCP_FLAG_ACK;
1078 return TCP_FLAG_FIN;
1080 clib_warning ("Shouldn't be here!");
1086 * Push TCP header and update connection variables
1089 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1090 tcp_state_t next_state, u8 compute_opts)
1092 u32 advertise_wnd, data_len;
1093 u8 tcp_hdr_opts_len, opts_write_len, flags;
1096 data_len = b->current_length + b->total_length_not_including_first_buffer;
1097 ASSERT (!b->total_length_not_including_first_buffer
1098 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1099 vnet_buffer (b)->tcp.flags = 0;
1102 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1104 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1105 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1106 flags = tcp_make_state_flags (tc, next_state);
1108 /* Push header and options */
1109 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1110 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1112 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1114 ASSERT (opts_write_len == tc->snd_opts_len);
1115 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1118 * Update connection variables
1121 tc->snd_nxt += data_len;
1122 tc->rcv_las = tc->rcv_nxt;
1124 /* TODO this is updated in output as well ... */
1125 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1127 tc->snd_una_max = tc->snd_nxt;
1128 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1131 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1135 tcp_send_ack (tcp_connection_t * tc)
1137 tcp_main_t *tm = vnet_get_tcp_main ();
1138 vlib_main_t *vm = vlib_get_main ();
1144 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1146 b = vlib_get_buffer (vm, bi);
1148 /* Fill in the ACK */
1149 tcp_make_ack (tc, b);
1150 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1154 * Delayed ack timer handler
1156 * Sends delayed ACK when timer expires
1159 tcp_timer_delack_handler (u32 index)
1161 u32 thread_index = vlib_get_thread_index ();
1162 tcp_connection_t *tc;
1164 tc = tcp_connection_get (index, thread_index);
1165 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1170 * Build a retransmit segment
1172 * @return the number of bytes in the segment or 0 if there's nothing to
1176 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1177 u32 max_deq_bytes, vlib_buffer_t ** b)
1179 tcp_main_t *tm = vnet_get_tcp_main ();
1180 vlib_main_t *vm = vlib_get_main ();
1182 u32 start, bi, available_bytes, seg_size;
1185 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1186 ASSERT (max_deq_bytes != 0);
1189 * Make sure we can retransmit something
1191 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1192 ASSERT (available_bytes >= offset);
1193 available_bytes -= offset;
1194 if (!available_bytes)
1196 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1197 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1199 /* Start is beyond snd_congestion */
1200 start = tc->snd_una + offset;
1201 if (seq_geq (start, tc->snd_congestion))
1204 /* Don't overshoot snd_congestion */
1205 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1207 max_deq_bytes = tc->snd_congestion - start;
1208 if (max_deq_bytes == 0)
1212 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1217 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1220 * Allocate and fill in buffer(s)
1223 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1225 *b = vlib_get_buffer (vm, bi);
1226 data = tcp_init_buffer (vm, *b);
1228 /* Easy case, buffer size greater than mss */
1229 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1231 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1233 ASSERT (n_bytes == max_deq_bytes);
1234 b[0]->current_length = n_bytes;
1235 tcp_push_hdr_i (tc, *b, tc->state, 0);
1237 /* Split mss into multiple buffers */
1240 u32 chain_bi = ~0, n_bufs_per_seg;
1241 u32 thread_index = vlib_get_thread_index ();
1242 u16 n_peeked, len_to_deq, available_bufs;
1243 vlib_buffer_t *chain_b, *prev_b;
1246 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1248 /* Make sure we have enough buffers */
1249 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1250 if (n_bufs_per_seg > available_bufs)
1252 if (tcp_alloc_tx_buffers (tm, thread_index,
1253 VLIB_FRAME_SIZE - available_bufs))
1255 tcp_return_buffer (tm);
1261 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1262 tm->bytes_per_buffer -
1264 b[0]->current_length = n_bytes;
1265 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1266 b[0]->total_length_not_including_first_buffer = 0;
1267 max_deq_bytes -= n_bytes;
1270 for (i = 1; i < n_bufs_per_seg; i++)
1273 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1274 tcp_get_free_buffer_index (tm, &chain_bi);
1275 ASSERT (chain_bi != (u32) ~ 0);
1276 chain_b = vlib_get_buffer (vm, chain_bi);
1277 chain_b->current_data = 0;
1278 data = vlib_buffer_get_current (chain_b);
1279 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1280 offset + n_bytes, len_to_deq);
1281 ASSERT (n_peeked == len_to_deq);
1282 n_bytes += n_peeked;
1283 chain_b->current_length = n_peeked;
1284 chain_b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
1285 chain_b->next_buffer = 0;
1287 /* update previous buffer */
1288 prev_b->next_buffer = chain_bi;
1289 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1291 max_deq_bytes -= n_peeked;
1292 b[0]->total_length_not_including_first_buffer += n_peeked;
1295 tcp_push_hdr_i (tc, *b, tc->state, 0);
1298 ASSERT (n_bytes > 0);
1299 ASSERT (((*b)->current_data + (*b)->current_length) <=
1300 tm->bytes_per_buffer);
1302 if (tcp_in_fastrecovery (tc))
1303 tc->snd_rxt_bytes += n_bytes;
1306 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1311 * Reset congestion control, switch cwnd to loss window and try again.
1314 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1316 tc->prev_ssthresh = tc->ssthresh;
1317 tc->prev_cwnd = tc->cwnd;
1319 /* Cleanly recover cc (also clears up fast retransmit) */
1320 if (tcp_in_fastrecovery (tc))
1321 tcp_cc_fastrecovery_exit (tc);
1323 /* Start again from the beginning */
1324 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1325 tc->cwnd = tcp_loss_wnd (tc);
1326 tc->snd_congestion = tc->snd_una_max;
1328 tcp_recovery_on (tc);
1332 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1334 tcp_main_t *tm = vnet_get_tcp_main ();
1335 vlib_main_t *vm = vlib_get_main ();
1336 u32 thread_index = vlib_get_thread_index ();
1337 tcp_connection_t *tc;
1338 vlib_buffer_t *b = 0;
1343 tc = tcp_half_open_connection_get (index);
1344 /* Note: the connection may have transitioned to ESTABLISHED... */
1345 if (PREDICT_FALSE (tc == 0))
1347 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1351 tc = tcp_connection_get (index, thread_index);
1352 /* Note: the connection may have been closed and pool_put */
1353 if (PREDICT_FALSE (tc == 0))
1355 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1358 if (tc->state >= TCP_STATE_ESTABLISHED)
1360 /* Lost FIN, retransmit and return */
1361 if (tcp_is_lost_fin (tc))
1367 /* We're not in recovery so make sure rto_boff is 0 */
1368 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1371 tcp_update_rto (tc);
1374 /* Increment RTO backoff (also equal to number of retries) and go back
1375 * to first un-acked byte */
1377 tc->snd_nxt = tc->snd_una;
1379 /* First retransmit timeout */
1380 if (tc->rto_boff == 1)
1381 tcp_rtx_timeout_cc (tc);
1383 /* Exponential backoff */
1384 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1386 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1388 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1389 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1391 /* TODO be less aggressive about this */
1392 scoreboard_clear (&tc->sack_sb);
1397 if (tc->snd_una == tc->snd_una_max)
1399 ASSERT (tc->rto_boff > 1 && tc->snd_una == tc->snd_congestion);
1400 clib_warning ("retransmit fail: %U", format_tcp_connection, tc, 2);
1401 /* Try again eventually */
1402 tcp_retransmit_timer_set (tc);
1406 bi = vlib_get_buffer_index (vm, b);
1408 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1409 if (tc->rto_boff == 1)
1410 tc->snd_rxt_ts = tcp_time_now ();
1412 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1413 tcp_retransmit_timer_update (tc);
1415 /* Retransmit for SYN */
1416 else if (tc->state == TCP_STATE_SYN_SENT)
1418 /* Half-open connection actually moved to established but we were
1419 * waiting for syn retransmit to pop to call cleanup from the right
1421 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1423 if (tcp_half_open_connection_cleanup (tc))
1425 clib_warning ("could not remove half-open connection");
1431 /* Try without increasing RTO a number of times. If this fails,
1432 * start growing RTO exponentially */
1434 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1435 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1437 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1440 b = vlib_get_buffer (vm, bi);
1441 tcp_init_buffer (vm, b);
1442 tcp_make_syn (tc, b);
1445 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1447 /* This goes straight to ipx_lookup. Retransmit timer set already */
1448 tcp_push_ip_hdr (tm, tc, b);
1449 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
1451 /* Retransmit SYN-ACK */
1452 else if (tc->state == TCP_STATE_SYN_RCVD)
1455 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1456 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1459 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1462 b = vlib_get_buffer (vm, bi);
1463 tcp_make_synack (tc, b);
1464 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1466 /* Retransmit timer already updated, just enqueue to output */
1467 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1471 ASSERT (tc->state == TCP_STATE_CLOSED);
1472 TCP_DBG ("connection state: %d", tc->state);
1478 tcp_timer_retransmit_handler (u32 index)
1480 tcp_timer_retransmit_handler_i (index, 0);
1484 tcp_timer_retransmit_syn_handler (u32 index)
1486 tcp_timer_retransmit_handler_i (index, 1);
1490 * Got 0 snd_wnd from peer, try to do something about it.
1494 tcp_timer_persist_handler (u32 index)
1496 tcp_main_t *tm = vnet_get_tcp_main ();
1497 vlib_main_t *vm = vlib_get_main ();
1498 u32 thread_index = vlib_get_thread_index ();
1499 tcp_connection_t *tc;
1501 u32 bi, old_snd_nxt, max_snd_bytes, available_bytes, offset;
1505 tc = tcp_connection_get_if_valid (index, thread_index);
1510 /* Make sure timer handle is set to invalid */
1511 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1513 /* Problem already solved or worse */
1514 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1515 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1518 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1519 offset = tc->snd_una_max - tc->snd_una;
1521 /* Reprogram persist if no new bytes available to send. We may have data
1523 if (!available_bytes)
1525 tcp_persist_timer_set (tc);
1529 if (available_bytes <= offset)
1531 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1535 /* Increment RTO backoff */
1537 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1540 * Try to force the first unsent segment (or buffer)
1542 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1544 b = vlib_get_buffer (vm, bi);
1545 data = tcp_init_buffer (vm, b);
1547 tcp_validate_txf_size (tc, offset);
1548 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1549 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1550 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1552 b->current_length = n_bytes;
1553 ASSERT (n_bytes != 0 && (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1
1554 || tcp_timer_is_active (tc,
1555 TCP_TIMER_RETRANSMIT)));
1557 /* Allow updating of snd_una_max but don't update snd_nxt */
1558 old_snd_nxt = tc->snd_nxt;
1559 tcp_push_hdr_i (tc, b, tc->state, 0);
1560 tc->snd_nxt = old_snd_nxt;
1561 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1563 /* Just sent new data, enable retransmit */
1564 tcp_retransmit_timer_update (tc);
1568 * Retransmit first unacked segment
1571 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1573 vlib_main_t *vm = vlib_get_main ();
1575 u32 bi, old_snd_nxt, n_bytes;
1577 old_snd_nxt = tc->snd_nxt;
1578 tc->snd_nxt = tc->snd_una;
1580 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1581 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1584 bi = vlib_get_buffer_index (vm, b);
1585 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1587 tc->snd_nxt = old_snd_nxt;
1591 * Do fast retransmit with SACKs
1594 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1596 vlib_main_t *vm = vlib_get_main ();
1597 u32 n_written = 0, offset, max_bytes;
1598 vlib_buffer_t *b = 0;
1599 sack_scoreboard_hole_t *hole;
1600 sack_scoreboard_t *sb;
1601 u32 bi, old_snd_nxt;
1603 u8 snd_limited = 0, can_rescue = 0;
1605 ASSERT (tcp_in_fastrecovery (tc));
1606 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1608 old_snd_nxt = tc->snd_nxt;
1610 snd_space = tcp_available_snd_space (tc);
1612 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1613 while (hole && snd_space > 0)
1615 hole = scoreboard_next_rxt_hole (sb, hole,
1616 tcp_fastrecovery_sent_1_smss (tc),
1617 &can_rescue, &snd_limited);
1620 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1621 || seq_gt (sb->rescue_rxt,
1622 tc->snd_congestion)))
1625 /* If rescue rxt undefined or less than snd_una then one segment of
1626 * up to SMSS octets that MUST include the highest outstanding
1627 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1628 * RecoveryPoint. HighRxt MUST NOT be updated.
1630 max_bytes = clib_min (tc->snd_mss,
1631 tc->snd_congestion - tc->snd_una);
1632 max_bytes = clib_min (max_bytes, snd_space);
1633 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1634 sb->rescue_rxt = tc->snd_congestion;
1635 tc->snd_nxt = tc->snd_una + offset;
1636 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1639 bi = vlib_get_buffer_index (vm, b);
1640 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1644 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1645 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1648 offset = sb->high_rxt - tc->snd_una;
1649 tc->snd_nxt = sb->high_rxt;
1650 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1652 /* Nothing left to retransmit */
1656 bi = vlib_get_buffer_index (vm, b);
1657 sb->high_rxt += n_written;
1658 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1659 ASSERT (n_written <= snd_space);
1660 snd_space -= n_written;
1663 /* If window allows, send 1 SMSS of new data */
1664 tc->snd_nxt = old_snd_nxt;
1668 * Fast retransmit without SACK info
1671 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1673 vlib_main_t *vm = vlib_get_main ();
1674 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1678 ASSERT (tcp_in_fastrecovery (tc));
1679 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1681 /* Start resending from first un-acked segment */
1682 old_snd_nxt = tc->snd_nxt;
1683 tc->snd_nxt = tc->snd_una;
1684 snd_space = tcp_available_snd_space (tc);
1686 while (snd_space > 0)
1688 offset += n_written;
1689 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1691 /* Nothing left to retransmit */
1695 bi = vlib_get_buffer_index (vm, b);
1696 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1697 snd_space -= n_written;
1700 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1701 tc->snd_nxt = old_snd_nxt;
1705 * Do fast retransmit
1708 tcp_fast_retransmit (tcp_connection_t * tc)
1710 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1711 && scoreboard_first_hole (&tc->sack_sb))
1712 tcp_fast_retransmit_sack (tc);
1714 tcp_fast_retransmit_no_sack (tc);
1718 tcp_session_has_ooo_data (tcp_connection_t * tc)
1720 stream_session_t *s =
1721 stream_session_get (tc->c_s_index, tc->c_thread_index);
1722 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1726 tcp46_output_inline (vlib_main_t * vm,
1727 vlib_node_runtime_t * node,
1728 vlib_frame_t * from_frame, int is_ip4)
1730 u32 n_left_from, next_index, *from, *to_next;
1731 u32 my_thread_index = vm->thread_index;
1733 from = vlib_frame_vector_args (from_frame);
1734 n_left_from = from_frame->n_vectors;
1735 next_index = node->cached_next_index;
1736 tcp_set_time_now (my_thread_index);
1738 while (n_left_from > 0)
1742 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1744 while (n_left_from > 0 && n_left_to_next > 0)
1748 tcp_connection_t *tc0;
1750 tcp_header_t *th0 = 0;
1751 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1758 n_left_to_next -= 1;
1760 b0 = vlib_get_buffer (vm, bi0);
1761 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1763 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1765 error0 = TCP_ERROR_INVALID_CONNECTION;
1766 next0 = TCP_OUTPUT_NEXT_DROP;
1770 th0 = vlib_buffer_get_current (b0);
1771 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1775 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1776 IP_PROTOCOL_TCP, 1);
1777 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1778 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1784 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1785 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1786 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1787 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1788 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1792 /* Filter out DUPACKs if there are no OOO segments left */
1794 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1796 if (!tcp_session_has_ooo_data (tc0))
1798 error0 = TCP_ERROR_FILTERED_DUPACKS;
1799 next0 = TCP_OUTPUT_NEXT_DROP;
1804 /* Stop DELACK timer and fix flags */
1805 tc0->flags &= ~(TCP_CONN_SNDACK);
1806 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1808 /* If not retransmitting
1809 * 1) update snd_una_max (SYN, SYNACK, FIN)
1810 * 2) If we're not tracking an ACK, start tracking */
1811 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1813 tc0->snd_una_max = tc0->snd_nxt;
1814 if (tc0->rtt_ts == 0)
1816 tc0->rtt_ts = tcp_time_now ();
1817 tc0->rtt_seq = tc0->snd_nxt;
1821 /* Set the retransmit timer if not set already and not
1822 * doing a pure ACK */
1823 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1824 && tc0->snd_nxt != tc0->snd_una)
1826 tcp_retransmit_timer_set (tc0);
1831 /* Make sure we haven't lost route to our peer */
1832 if (PREDICT_FALSE (tc0->last_fib_check
1833 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1836 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1838 tc0->last_fib_check = tc0->snd_opts.tsval;
1842 clib_warning ("lost connection to peer");
1843 tcp_connection_reset (tc0);
1848 /* Use pre-computed dpo to set next node */
1849 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1850 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1853 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1854 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1856 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1858 b0->error = node->errors[error0];
1859 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1861 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1864 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1868 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1870 clib_memcpy (&t0->tcp_connection, tc0,
1871 sizeof (t0->tcp_connection));
1874 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1875 n_left_to_next, bi0, next0);
1878 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1881 return from_frame->n_vectors;
1885 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1886 vlib_frame_t * from_frame)
1888 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1892 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1893 vlib_frame_t * from_frame)
1895 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1899 VLIB_REGISTER_NODE (tcp4_output_node) =
1901 .function = tcp4_output,.name = "tcp4-output",
1902 /* Takes a vector of packets. */
1903 .vector_size = sizeof (u32),
1904 .n_errors = TCP_N_ERROR,
1905 .error_strings = tcp_error_strings,
1906 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1908 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1909 foreach_tcp4_output_next
1912 .format_buffer = format_tcp_header,
1913 .format_trace = format_tcp_tx_trace,
1917 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1920 VLIB_REGISTER_NODE (tcp6_output_node) =
1922 .function = tcp6_output,
1923 .name = "tcp6-output",
1924 /* Takes a vector of packets. */
1925 .vector_size = sizeof (u32),
1926 .n_errors = TCP_N_ERROR,
1927 .error_strings = tcp_error_strings,
1928 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1930 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1931 foreach_tcp6_output_next
1934 .format_buffer = format_tcp_header,
1935 .format_trace = format_tcp_tx_trace,
1939 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1942 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1944 tcp_connection_t *tc;
1946 tc = (tcp_connection_t *) tconn;
1947 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1948 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1950 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1952 tc->rtt_ts = tcp_time_now ();
1953 tc->rtt_seq = tc->snd_nxt;
1958 typedef enum _tcp_reset_next
1960 TCP_RESET_NEXT_DROP,
1961 TCP_RESET_NEXT_IP_LOOKUP,
1965 #define foreach_tcp4_reset_next \
1966 _(DROP, "error-drop") \
1967 _(IP_LOOKUP, "ip4-lookup")
1969 #define foreach_tcp6_reset_next \
1970 _(DROP, "error-drop") \
1971 _(IP_LOOKUP, "ip6-lookup")
1974 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
1975 vlib_frame_t * from_frame, u8 is_ip4)
1977 u32 n_left_from, next_index, *from, *to_next;
1978 u32 my_thread_index = vm->thread_index;
1980 from = vlib_frame_vector_args (from_frame);
1981 n_left_from = from_frame->n_vectors;
1983 next_index = node->cached_next_index;
1985 while (n_left_from > 0)
1989 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1991 while (n_left_from > 0 && n_left_to_next > 0)
1997 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
2004 n_left_to_next -= 1;
2006 b0 = vlib_get_buffer (vm, bi0);
2008 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
2009 my_thread_index, is_ip4))
2011 error0 = TCP_ERROR_LOOKUP_DROPS;
2012 next0 = TCP_RESET_NEXT_DROP;
2016 /* Prepare to send to IP lookup */
2017 vnet_buffer (b0)->sw_if_index[VLIB_TX] = 0;
2018 next0 = TCP_RESET_NEXT_IP_LOOKUP;
2021 b0->error = node->errors[error0];
2022 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
2023 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
2025 th0 = vlib_buffer_get_current (b0);
2027 th0 = ip4_next_header ((ip4_header_t *) th0);
2029 th0 = ip6_next_header ((ip6_header_t *) th0);
2030 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
2031 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
2034 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
2035 n_left_to_next, bi0, next0);
2037 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
2039 return from_frame->n_vectors;
2043 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2044 vlib_frame_t * from_frame)
2046 return tcp46_send_reset_inline (vm, node, from_frame, 1);
2050 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2051 vlib_frame_t * from_frame)
2053 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2057 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2058 .function = tcp4_send_reset,
2059 .name = "tcp4-reset",
2060 .vector_size = sizeof (u32),
2061 .n_errors = TCP_N_ERROR,
2062 .error_strings = tcp_error_strings,
2063 .n_next_nodes = TCP_RESET_N_NEXT,
2065 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2066 foreach_tcp4_reset_next
2069 .format_trace = format_tcp_tx_trace,
2073 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2076 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2077 .function = tcp6_send_reset,
2078 .name = "tcp6-reset",
2079 .vector_size = sizeof (u32),
2080 .n_errors = TCP_N_ERROR,
2081 .error_strings = tcp_error_strings,
2082 .n_next_nodes = TCP_RESET_N_NEXT,
2084 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2085 foreach_tcp6_reset_next
2088 .format_trace = format_tcp_tx_trace,
2092 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2095 * fd.io coding-style-patch-verification: ON
2098 * eval: (c-set-style "gnu")