2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #include <vnet/tcp/tcp.h>
17 #include <vnet/lisp-cp/packets.h>
20 vlib_node_registration_t tcp4_output_node;
21 vlib_node_registration_t tcp6_output_node;
23 typedef enum _tcp_output_next
26 TCP_OUTPUT_NEXT_IP_LOOKUP,
30 #define foreach_tcp4_output_next \
31 _ (DROP, "error-drop") \
32 _ (IP_LOOKUP, "ip4-lookup")
34 #define foreach_tcp6_output_next \
35 _ (DROP, "error-drop") \
36 _ (IP_LOOKUP, "ip6-lookup")
38 static char *tcp_error_strings[] = {
39 #define tcp_error(n,s) s,
40 #include <vnet/tcp/tcp_error.def>
46 tcp_header_t tcp_header;
47 tcp_connection_t tcp_connection;
53 format_tcp_tx_trace (u8 * s, va_list * args)
55 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
56 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
57 tcp_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *);
58 u32 indent = format_get_indent (s);
60 s = format (s, "%U\n%U%U",
61 format_tcp_header, &t->tcp_header, 128,
62 format_white_space, indent,
63 format_tcp_connection, &t->tcp_connection, 1);
69 tcp_window_compute_scale (u32 window)
72 while (wnd_scale < TCP_MAX_WND_SCALE && (window >> wnd_scale) > TCP_WND_MAX)
78 * Update max segment size we're able to process.
80 * The value is constrained by our interface's MTU and IP options. It is
81 * also what we advertise to our peer.
84 tcp_update_rcv_mss (tcp_connection_t * tc)
86 /* TODO find our iface MTU */
87 tc->mss = dummy_mtu - sizeof (tcp_header_t);
91 * TCP's initial window
94 tcp_initial_wnd_unscaled (tcp_connection_t * tc)
96 /* RFC 6928 recommends the value lower. However at the time our connections
97 * are initialized, fifos may not be allocated. Therefore, advertise the
98 * smallest possible unscaled window size and update once fifos are
99 * assigned to the session.
102 tcp_update_rcv_mss (tc);
103 TCP_IW_N_SEGMENTS * tc->mss;
105 return TCP_MIN_RX_FIFO_SIZE;
109 * Compute initial window and scale factor. As per RFC1323, window field in
110 * SYN and SYN-ACK segments is never scaled.
113 tcp_initial_window_to_advertise (tcp_connection_t * tc)
117 /* Initial wnd for SYN. Fifos are not allocated yet.
118 * Use some predefined value. For SYN-ACK we still want the
119 * scale to be computed in the same way */
120 max_fifo = TCP_MAX_RX_FIFO_SIZE;
122 tc->rcv_wscale = tcp_window_compute_scale (max_fifo);
123 tc->rcv_wnd = tcp_initial_wnd_unscaled (tc);
125 return clib_min (tc->rcv_wnd, TCP_WND_MAX);
129 * Compute and return window to advertise, scaled as per RFC1323
132 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
134 if (state < TCP_STATE_ESTABLISHED)
135 return tcp_initial_window_to_advertise (tc);
137 tcp_update_rcv_wnd (tc);
139 if (tc->rcv_wnd == 0)
141 tc->flags |= TCP_CONN_SENT_RCV_WND0;
145 tc->flags &= ~TCP_CONN_SENT_RCV_WND0;
148 return tc->rcv_wnd >> tc->rcv_wscale;
152 tcp_update_rcv_wnd (tcp_connection_t * tc)
155 u32 available_space, max_fifo, wnd;
158 * Figure out how much space we have available
160 available_space = stream_session_max_rx_enqueue (&tc->connection);
161 max_fifo = stream_session_rx_fifo_size (&tc->connection);
163 ASSERT (tc->rcv_opts.mss < max_fifo);
164 if (available_space < tc->rcv_opts.mss && available_space < max_fifo >> 3)
168 * Use the above and what we know about what we've previously advertised
169 * to compute the new window
171 observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las);
172 if (observed_wnd < 0)
175 /* Bad. Thou shalt not shrink */
176 if (available_space < observed_wnd)
179 TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
183 wnd = available_space;
186 /* Make sure we have a multiple of rcv_wscale */
187 if (wnd && tc->rcv_wscale)
189 wnd &= ~(1 << tc->rcv_wscale);
191 wnd = 1 << tc->rcv_wscale;
194 tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
198 * Write TCP options to segment.
201 tcp_options_write (u8 * data, tcp_options_t * opts)
204 u32 buf, seq_len = 4;
206 if (tcp_opts_mss (opts))
208 *data++ = TCP_OPTION_MSS;
209 *data++ = TCP_OPTION_LEN_MSS;
210 buf = clib_host_to_net_u16 (opts->mss);
211 clib_memcpy (data, &buf, sizeof (opts->mss));
212 data += sizeof (opts->mss);
213 opts_len += TCP_OPTION_LEN_MSS;
216 if (tcp_opts_wscale (opts))
218 *data++ = TCP_OPTION_WINDOW_SCALE;
219 *data++ = TCP_OPTION_LEN_WINDOW_SCALE;
220 *data++ = opts->wscale;
221 opts_len += TCP_OPTION_LEN_WINDOW_SCALE;
224 if (tcp_opts_sack_permitted (opts))
226 *data++ = TCP_OPTION_SACK_PERMITTED;
227 *data++ = TCP_OPTION_LEN_SACK_PERMITTED;
228 opts_len += TCP_OPTION_LEN_SACK_PERMITTED;
231 if (tcp_opts_tstamp (opts))
233 *data++ = TCP_OPTION_TIMESTAMP;
234 *data++ = TCP_OPTION_LEN_TIMESTAMP;
235 buf = clib_host_to_net_u32 (opts->tsval);
236 clib_memcpy (data, &buf, sizeof (opts->tsval));
237 data += sizeof (opts->tsval);
238 buf = clib_host_to_net_u32 (opts->tsecr);
239 clib_memcpy (data, &buf, sizeof (opts->tsecr));
240 data += sizeof (opts->tsecr);
241 opts_len += TCP_OPTION_LEN_TIMESTAMP;
244 if (tcp_opts_sack (opts))
247 u32 n_sack_blocks = clib_min (vec_len (opts->sacks),
248 TCP_OPTS_MAX_SACK_BLOCKS);
250 if (n_sack_blocks != 0)
252 *data++ = TCP_OPTION_SACK_BLOCK;
253 *data++ = 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
254 for (i = 0; i < n_sack_blocks; i++)
256 buf = clib_host_to_net_u32 (opts->sacks[i].start);
257 clib_memcpy (data, &buf, seq_len);
259 buf = clib_host_to_net_u32 (opts->sacks[i].end);
260 clib_memcpy (data, &buf, seq_len);
263 opts_len += 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
267 /* Terminate TCP options */
270 *data++ = TCP_OPTION_EOL;
271 opts_len += TCP_OPTION_LEN_EOL;
274 /* Pad with zeroes to a u32 boundary */
277 *data++ = TCP_OPTION_NOOP;
278 opts_len += TCP_OPTION_LEN_NOOP;
284 tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale)
288 opts->flags |= TCP_OPTS_FLAG_MSS;
289 opts->mss = dummy_mtu; /*XXX discover that */
290 len += TCP_OPTION_LEN_MSS;
292 opts->flags |= TCP_OPTS_FLAG_WSCALE;
293 opts->wscale = wnd_scale;
294 len += TCP_OPTION_LEN_WINDOW_SCALE;
296 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
297 opts->tsval = tcp_time_now ();
299 len += TCP_OPTION_LEN_TIMESTAMP;
303 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
304 len += TCP_OPTION_LEN_SACK_PERMITTED;
307 /* Align to needed boundary */
308 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
313 tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
317 opts->flags |= TCP_OPTS_FLAG_MSS;
319 len += TCP_OPTION_LEN_MSS;
321 if (tcp_opts_wscale (&tc->rcv_opts))
323 opts->flags |= TCP_OPTS_FLAG_WSCALE;
324 opts->wscale = tc->rcv_wscale;
325 len += TCP_OPTION_LEN_WINDOW_SCALE;
328 if (tcp_opts_tstamp (&tc->rcv_opts))
330 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
331 opts->tsval = tcp_time_now ();
332 opts->tsecr = tc->tsval_recent;
333 len += TCP_OPTION_LEN_TIMESTAMP;
336 if (tcp_opts_sack_permitted (&tc->rcv_opts))
338 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
339 len += TCP_OPTION_LEN_SACK_PERMITTED;
342 /* Align to needed boundary */
343 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
348 tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
354 if (tcp_opts_tstamp (&tc->rcv_opts))
356 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
357 opts->tsval = tcp_time_now ();
358 opts->tsecr = tc->tsval_recent;
359 len += TCP_OPTION_LEN_TIMESTAMP;
361 if (tcp_opts_sack_permitted (&tc->rcv_opts))
363 if (vec_len (tc->snd_sacks))
365 opts->flags |= TCP_OPTS_FLAG_SACK;
366 opts->sacks = tc->snd_sacks;
367 opts->n_sack_blocks = clib_min (vec_len (tc->snd_sacks),
368 TCP_OPTS_MAX_SACK_BLOCKS);
369 len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks;
373 /* Align to needed boundary */
374 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
379 tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
384 case TCP_STATE_ESTABLISHED:
385 case TCP_STATE_FIN_WAIT_1:
386 return tcp_make_established_options (tc, opts);
387 case TCP_STATE_SYN_RCVD:
388 return tcp_make_synack_options (tc, opts);
389 case TCP_STATE_SYN_SENT:
390 return tcp_make_syn_options (opts, tc->rcv_wscale);
392 clib_warning ("Not handled!");
398 * Update snd_mss to reflect the effective segment size that we can send
399 * by taking into account all TCP options, including SACKs
402 tcp_update_snd_mss (tcp_connection_t * tc)
404 /* Compute options to be used for connection. These may be reused when
405 * sending data or to compute the effective mss (snd_mss) */
407 tcp_make_options (tc, &tc->snd_opts, TCP_STATE_ESTABLISHED);
409 /* XXX check if MTU has been updated */
410 tc->snd_mss = clib_min (tc->mss, tc->rcv_opts.mss) - tc->snd_opts_len;
411 ASSERT (tc->snd_mss > 0);
415 tcp_init_mss (tcp_connection_t * tc)
417 u16 default_min_mss = 536;
418 tcp_update_rcv_mss (tc);
420 /* TODO cache mss and consider PMTU discovery */
421 tc->snd_mss = clib_min (tc->rcv_opts.mss, tc->mss);
423 if (tc->snd_mss < 45)
425 clib_warning ("snd mss is 0");
426 /* Assume that at least the min default mss works */
427 tc->snd_mss = default_min_mss;
428 tc->rcv_opts.mss = default_min_mss;
431 /* We should have enough space for 40 bytes of options */
432 ASSERT (tc->snd_mss > 45);
434 /* If we use timestamp option, account for it */
435 if (tcp_opts_tstamp (&tc->rcv_opts))
436 tc->snd_mss -= TCP_OPTION_LEN_TIMESTAMP;
440 tcp_alloc_tx_buffers (tcp_main_t * tm, u8 thread_index, u32 n_free_buffers)
442 vlib_main_t *vm = vlib_get_main ();
443 u32 current_length = vec_len (tm->tx_buffers[thread_index]);
446 vec_validate (tm->tx_buffers[thread_index],
447 current_length + n_free_buffers - 1);
449 vlib_buffer_alloc (vm, &tm->tx_buffers[thread_index][current_length],
451 _vec_len (tm->tx_buffers[thread_index]) = current_length + n_allocated;
452 /* buffer shortage, report failure */
453 if (vec_len (tm->tx_buffers[thread_index]) == 0)
455 clib_warning ("out of buffers");
462 tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx)
465 u32 thread_index = vlib_get_thread_index ();
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;
924 ih4 = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip.ip4,
925 &tc->c_rmt_ip.ip4, IP_PROTOCOL_TCP, 0);
926 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
932 ih6 = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip.ip6,
933 &tc->c_rmt_ip.ip6, IP_PROTOCOL_TCP);
934 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
937 tcp_enqueue_to_ip_lookup_now (vm, b, bi, tc->c_is_ip4);
938 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
942 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
944 tcp_header_t *th = vlib_buffer_get_current (b);
945 vlib_main_t *vm = vlib_get_main ();
949 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
950 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
951 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
958 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
959 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
960 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
968 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
969 * The packet is not forwarded through tcpx_output to avoid doing lookups
970 * in the half_open pool.
973 tcp_send_syn (tcp_connection_t * tc)
977 tcp_main_t *tm = vnet_get_tcp_main ();
978 vlib_main_t *vm = vlib_get_main ();
980 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
983 b = vlib_get_buffer (vm, bi);
984 tcp_init_buffer (vm, b);
985 tcp_make_syn (tc, b);
987 /* Measure RTT with this */
988 tc->rtt_ts = tcp_time_now ();
989 tc->rtt_seq = tc->snd_nxt;
992 /* Set the connection establishment timer */
993 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
995 tcp_push_ip_hdr (tm, tc, b);
996 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
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 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1060 b = vlib_get_buffer (vm, bi);
1061 fin_snt = tc->flags & TCP_CONN_FINSNT;
1063 tc->snd_nxt = tc->snd_una;
1064 tcp_make_fin (tc, b);
1065 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
1068 tc->flags |= TCP_CONN_FINSNT;
1069 tc->flags &= ~TCP_CONN_FINPNDG;
1070 /* Account for the FIN */
1071 tc->snd_una_max += 1;
1072 tc->snd_nxt = tc->snd_una_max;
1076 tc->snd_nxt = tc->snd_una_max;
1078 tcp_retransmit_timer_force_update (tc);
1079 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1083 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1087 case TCP_STATE_ESTABLISHED:
1088 return TCP_FLAG_ACK;
1089 case TCP_STATE_SYN_RCVD:
1090 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1091 case TCP_STATE_SYN_SENT:
1092 return TCP_FLAG_SYN;
1093 case TCP_STATE_LAST_ACK:
1094 case TCP_STATE_FIN_WAIT_1:
1095 if (tc->snd_nxt + 1 < tc->snd_una_max)
1096 return TCP_FLAG_ACK;
1098 return TCP_FLAG_FIN;
1100 clib_warning ("Shouldn't be here!");
1106 * Push TCP header and update connection variables
1109 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1110 tcp_state_t next_state, u8 compute_opts)
1112 u32 advertise_wnd, data_len;
1113 u8 tcp_hdr_opts_len, opts_write_len, flags;
1116 data_len = b->current_length + b->total_length_not_including_first_buffer;
1117 ASSERT (!b->total_length_not_including_first_buffer
1118 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1119 vnet_buffer (b)->tcp.flags = 0;
1122 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1124 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1125 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1126 flags = tcp_make_state_flags (tc, next_state);
1128 /* Push header and options */
1129 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1130 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1132 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1134 ASSERT (opts_write_len == tc->snd_opts_len);
1135 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1138 * Update connection variables
1141 tc->snd_nxt += data_len;
1142 tc->rcv_las = tc->rcv_nxt;
1144 /* TODO this is updated in output as well ... */
1145 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1147 tc->snd_una_max = tc->snd_nxt;
1148 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1151 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1155 tcp_send_ack (tcp_connection_t * tc)
1157 tcp_main_t *tm = vnet_get_tcp_main ();
1158 vlib_main_t *vm = vlib_get_main ();
1164 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1166 b = vlib_get_buffer (vm, bi);
1168 /* Fill in the ACK */
1169 tcp_make_ack (tc, b);
1170 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1174 * Delayed ack timer handler
1176 * Sends delayed ACK when timer expires
1179 tcp_timer_delack_handler (u32 index)
1181 u32 thread_index = vlib_get_thread_index ();
1182 tcp_connection_t *tc;
1184 tc = tcp_connection_get (index, thread_index);
1185 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1190 * Build a retransmit segment
1192 * @return the number of bytes in the segment or 0 if there's nothing to
1196 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1197 u32 max_deq_bytes, vlib_buffer_t ** b)
1199 tcp_main_t *tm = vnet_get_tcp_main ();
1200 vlib_main_t *vm = vlib_get_main ();
1202 u32 start, bi, available_bytes, seg_size;
1205 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1206 ASSERT (max_deq_bytes != 0);
1209 * Make sure we can retransmit something
1211 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1212 ASSERT (available_bytes >= offset);
1213 available_bytes -= offset;
1214 if (!available_bytes)
1216 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1217 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1219 /* Start is beyond snd_congestion */
1220 start = tc->snd_una + offset;
1221 if (seq_geq (start, tc->snd_congestion))
1224 /* Don't overshoot snd_congestion */
1225 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1227 max_deq_bytes = tc->snd_congestion - start;
1228 if (max_deq_bytes == 0)
1232 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1237 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1240 * Allocate and fill in buffer(s)
1243 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1245 *b = vlib_get_buffer (vm, bi);
1246 data = tcp_init_buffer (vm, *b);
1248 /* Easy case, buffer size greater than mss */
1249 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1251 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1253 ASSERT (n_bytes == max_deq_bytes);
1254 b[0]->current_length = n_bytes;
1255 tcp_push_hdr_i (tc, *b, tc->state, 0);
1257 /* Split mss into multiple buffers */
1260 u32 chain_bi = ~0, n_bufs_per_seg;
1261 u32 thread_index = vlib_get_thread_index ();
1262 u16 n_peeked, len_to_deq, available_bufs;
1263 vlib_buffer_t *chain_b, *prev_b;
1266 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1268 /* Make sure we have enough buffers */
1269 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1270 if (n_bufs_per_seg > available_bufs)
1272 if (tcp_alloc_tx_buffers (tm, thread_index,
1273 VLIB_FRAME_SIZE - available_bufs))
1275 tcp_return_buffer (tm);
1281 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1282 tm->bytes_per_buffer -
1284 b[0]->current_length = n_bytes;
1285 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1286 b[0]->total_length_not_including_first_buffer = 0;
1287 max_deq_bytes -= n_bytes;
1290 for (i = 1; i < n_bufs_per_seg; i++)
1293 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1294 tcp_get_free_buffer_index (tm, &chain_bi);
1295 ASSERT (chain_bi != (u32) ~ 0);
1296 chain_b = vlib_get_buffer (vm, chain_bi);
1297 chain_b->current_data = 0;
1298 data = vlib_buffer_get_current (chain_b);
1299 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1300 offset + n_bytes, len_to_deq);
1301 ASSERT (n_peeked == len_to_deq);
1302 n_bytes += n_peeked;
1303 chain_b->current_length = n_peeked;
1304 chain_b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
1305 chain_b->next_buffer = 0;
1307 /* update previous buffer */
1308 prev_b->next_buffer = chain_bi;
1309 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1311 max_deq_bytes -= n_peeked;
1312 b[0]->total_length_not_including_first_buffer += n_peeked;
1315 tcp_push_hdr_i (tc, *b, tc->state, 0);
1318 ASSERT (n_bytes > 0);
1319 ASSERT (((*b)->current_data + (*b)->current_length) <=
1320 tm->bytes_per_buffer);
1322 if (tcp_in_fastrecovery (tc))
1323 tc->snd_rxt_bytes += n_bytes;
1326 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1331 * Reset congestion control, switch cwnd to loss window and try again.
1334 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1336 tc->prev_ssthresh = tc->ssthresh;
1337 tc->prev_cwnd = tc->cwnd;
1339 /* Cleanly recover cc (also clears up fast retransmit) */
1340 if (tcp_in_fastrecovery (tc))
1341 tcp_cc_fastrecovery_exit (tc);
1343 /* Start again from the beginning */
1344 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1345 tc->cwnd = tcp_loss_wnd (tc);
1346 tc->snd_congestion = tc->snd_una_max;
1348 tcp_recovery_on (tc);
1352 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1354 tcp_main_t *tm = vnet_get_tcp_main ();
1355 vlib_main_t *vm = vlib_get_main ();
1356 u32 thread_index = vlib_get_thread_index ();
1357 tcp_connection_t *tc;
1358 vlib_buffer_t *b = 0;
1363 tc = tcp_half_open_connection_get (index);
1364 /* Note: the connection may have transitioned to ESTABLISHED... */
1365 if (PREDICT_FALSE (tc == 0))
1367 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1371 tc = tcp_connection_get (index, thread_index);
1372 /* Note: the connection may have been closed and pool_put */
1373 if (PREDICT_FALSE (tc == 0))
1375 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1378 if (tc->state >= TCP_STATE_ESTABLISHED)
1380 /* Lost FIN, retransmit and return */
1381 if (tcp_is_lost_fin (tc))
1387 /* Shouldn't be here */
1388 if (tc->snd_una == tc->snd_una_max)
1390 tcp_recovery_off (tc);
1394 /* We're not in recovery so make sure rto_boff is 0 */
1395 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1398 tcp_update_rto (tc);
1401 /* Increment RTO backoff (also equal to number of retries) and go back
1402 * to first un-acked byte */
1405 /* First retransmit timeout */
1406 if (tc->rto_boff == 1)
1407 tcp_rtx_timeout_cc (tc);
1409 tc->snd_nxt = tc->snd_una;
1410 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1412 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1414 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1415 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1417 /* TODO be less aggressive about this */
1418 scoreboard_clear (&tc->sack_sb);
1423 if (tc->snd_una == tc->snd_una_max)
1425 ASSERT (tc->rto_boff > 1 && tc->snd_una == tc->snd_congestion);
1426 clib_warning ("retransmit fail: %U", format_tcp_connection, tc, 2);
1427 /* Try again eventually */
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 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1466 b = vlib_get_buffer (vm, bi);
1467 tcp_init_buffer (vm, b);
1468 tcp_make_syn (tc, b);
1471 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1473 /* This goes straight to ipx_lookup. Retransmit timer set already */
1474 tcp_push_ip_hdr (tm, tc, b);
1475 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
1477 /* Retransmit SYN-ACK */
1478 else if (tc->state == TCP_STATE_SYN_RCVD)
1481 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1482 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1485 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1488 b = vlib_get_buffer (vm, bi);
1489 tcp_make_synack (tc, b);
1490 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1492 /* Retransmit timer already updated, just enqueue to output */
1493 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1497 ASSERT (tc->state == TCP_STATE_CLOSED);
1499 TCP_DBG ("connection state: %U", format_tcp_connection, tc, 2);
1505 tcp_timer_retransmit_handler (u32 index)
1507 tcp_timer_retransmit_handler_i (index, 0);
1511 tcp_timer_retransmit_syn_handler (u32 index)
1513 tcp_timer_retransmit_handler_i (index, 1);
1517 * Got 0 snd_wnd from peer, try to do something about it.
1521 tcp_timer_persist_handler (u32 index)
1523 tcp_main_t *tm = vnet_get_tcp_main ();
1524 vlib_main_t *vm = vlib_get_main ();
1525 u32 thread_index = vlib_get_thread_index ();
1526 tcp_connection_t *tc;
1528 u32 bi, max_snd_bytes, available_bytes, offset;
1532 tc = tcp_connection_get_if_valid (index, thread_index);
1537 /* Make sure timer handle is set to invalid */
1538 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1540 /* Problem already solved or worse */
1541 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1542 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1545 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1546 offset = tc->snd_una_max - tc->snd_una;
1548 /* Reprogram persist if no new bytes available to send. We may have data
1550 if (!available_bytes)
1552 tcp_persist_timer_set (tc);
1556 if (available_bytes <= offset)
1558 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1562 /* Increment RTO backoff */
1564 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1567 * Try to force the first unsent segment (or buffer)
1569 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1571 b = vlib_get_buffer (vm, bi);
1572 data = tcp_init_buffer (vm, b);
1574 tcp_validate_txf_size (tc, offset);
1575 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1576 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1577 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1579 b->current_length = n_bytes;
1580 ASSERT (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)
1581 || tc->snd_nxt == tc->snd_una_max
1582 || tc->rto_boff > 1));
1584 tcp_push_hdr_i (tc, b, tc->state, 0);
1585 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1587 /* Just sent new data, enable retransmit */
1588 tcp_retransmit_timer_update (tc);
1592 * Retransmit first unacked segment
1595 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1597 vlib_main_t *vm = vlib_get_main ();
1599 u32 bi, old_snd_nxt, n_bytes;
1601 old_snd_nxt = tc->snd_nxt;
1602 tc->snd_nxt = tc->snd_una;
1604 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1605 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1608 bi = vlib_get_buffer_index (vm, b);
1609 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1611 tc->snd_nxt = old_snd_nxt;
1615 * Do fast retransmit with SACKs
1618 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1620 vlib_main_t *vm = vlib_get_main ();
1621 u32 n_written = 0, offset, max_bytes;
1622 vlib_buffer_t *b = 0;
1623 sack_scoreboard_hole_t *hole;
1624 sack_scoreboard_t *sb;
1625 u32 bi, old_snd_nxt;
1627 u8 snd_limited = 0, can_rescue = 0;
1629 ASSERT (tcp_in_fastrecovery (tc));
1630 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1632 old_snd_nxt = tc->snd_nxt;
1634 snd_space = tcp_available_snd_space (tc);
1636 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1637 while (hole && snd_space > 0)
1639 hole = scoreboard_next_rxt_hole (sb, hole,
1640 tcp_fastrecovery_sent_1_smss (tc),
1641 &can_rescue, &snd_limited);
1644 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1645 || seq_gt (sb->rescue_rxt,
1646 tc->snd_congestion)))
1649 /* If rescue rxt undefined or less than snd_una then one segment of
1650 * up to SMSS octets that MUST include the highest outstanding
1651 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1652 * RecoveryPoint. HighRxt MUST NOT be updated.
1654 max_bytes = clib_min (tc->snd_mss,
1655 tc->snd_congestion - tc->snd_una);
1656 max_bytes = clib_min (max_bytes, snd_space);
1657 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1658 sb->rescue_rxt = tc->snd_congestion;
1659 tc->snd_nxt = tc->snd_una + offset;
1660 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1663 bi = vlib_get_buffer_index (vm, b);
1664 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1668 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1669 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1672 offset = sb->high_rxt - tc->snd_una;
1673 tc->snd_nxt = sb->high_rxt;
1674 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1676 /* Nothing left to retransmit */
1680 bi = vlib_get_buffer_index (vm, b);
1681 sb->high_rxt += n_written;
1682 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1683 ASSERT (n_written <= snd_space);
1684 snd_space -= n_written;
1687 /* If window allows, send 1 SMSS of new data */
1688 tc->snd_nxt = old_snd_nxt;
1692 * Fast retransmit without SACK info
1695 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1697 vlib_main_t *vm = vlib_get_main ();
1698 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1702 ASSERT (tcp_in_fastrecovery (tc));
1703 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1705 /* Start resending from first un-acked segment */
1706 old_snd_nxt = tc->snd_nxt;
1707 tc->snd_nxt = tc->snd_una;
1708 snd_space = tcp_available_snd_space (tc);
1710 while (snd_space > 0)
1712 offset += n_written;
1713 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1715 /* Nothing left to retransmit */
1719 bi = vlib_get_buffer_index (vm, b);
1720 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1721 snd_space -= n_written;
1724 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1725 tc->snd_nxt = old_snd_nxt;
1729 * Do fast retransmit
1732 tcp_fast_retransmit (tcp_connection_t * tc)
1734 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1735 && scoreboard_first_hole (&tc->sack_sb))
1736 tcp_fast_retransmit_sack (tc);
1738 tcp_fast_retransmit_no_sack (tc);
1742 tcp_session_has_ooo_data (tcp_connection_t * tc)
1744 stream_session_t *s = session_get (tc->c_s_index, tc->c_thread_index);
1745 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1749 tcp46_output_inline (vlib_main_t * vm,
1750 vlib_node_runtime_t * node,
1751 vlib_frame_t * from_frame, int is_ip4)
1753 u32 n_left_from, next_index, *from, *to_next;
1754 u32 my_thread_index = vm->thread_index;
1756 from = vlib_frame_vector_args (from_frame);
1757 n_left_from = from_frame->n_vectors;
1758 next_index = node->cached_next_index;
1759 tcp_set_time_now (my_thread_index);
1761 while (n_left_from > 0)
1765 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1767 while (n_left_from > 0 && n_left_to_next > 0)
1771 tcp_connection_t *tc0;
1773 tcp_header_t *th0 = 0;
1774 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1781 n_left_to_next -= 1;
1783 b0 = vlib_get_buffer (vm, bi0);
1784 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1786 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1788 error0 = TCP_ERROR_INVALID_CONNECTION;
1789 next0 = TCP_OUTPUT_NEXT_DROP;
1793 th0 = vlib_buffer_get_current (b0);
1794 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1798 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1799 IP_PROTOCOL_TCP, 1);
1800 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1801 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1807 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1808 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1809 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1810 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1811 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1815 /* Filter out DUPACKs if there are no OOO segments left */
1817 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1819 if (!tcp_session_has_ooo_data (tc0))
1821 error0 = TCP_ERROR_FILTERED_DUPACKS;
1822 next0 = TCP_OUTPUT_NEXT_DROP;
1827 /* Stop DELACK timer and fix flags */
1828 tc0->flags &= ~(TCP_CONN_SNDACK);
1829 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1831 /* If not retransmitting
1832 * 1) update snd_una_max (SYN, SYNACK, FIN)
1833 * 2) If we're not tracking an ACK, start tracking */
1834 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1836 tc0->snd_una_max = tc0->snd_nxt;
1837 if (tc0->rtt_ts == 0)
1839 tc0->rtt_ts = tcp_time_now ();
1840 tc0->rtt_seq = tc0->snd_nxt;
1844 /* Set the retransmit timer if not set already and not
1845 * doing a pure ACK */
1846 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1847 && tc0->snd_nxt != tc0->snd_una)
1849 tcp_retransmit_timer_set (tc0);
1854 /* Make sure we haven't lost route to our peer */
1855 if (PREDICT_FALSE (tc0->last_fib_check
1856 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1859 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1861 tc0->last_fib_check = tc0->snd_opts.tsval;
1865 clib_warning ("lost connection to peer");
1866 tcp_connection_reset (tc0);
1871 /* Use pre-computed dpo to set next node */
1872 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1873 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1876 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1877 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1879 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1881 b0->error = node->errors[error0];
1882 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1884 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1887 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1891 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1893 clib_memcpy (&t0->tcp_connection, tc0,
1894 sizeof (t0->tcp_connection));
1897 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1898 n_left_to_next, bi0, next0);
1901 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1904 return from_frame->n_vectors;
1908 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1909 vlib_frame_t * from_frame)
1911 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1915 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1916 vlib_frame_t * from_frame)
1918 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1922 VLIB_REGISTER_NODE (tcp4_output_node) =
1924 .function = tcp4_output,.name = "tcp4-output",
1925 /* Takes a vector of packets. */
1926 .vector_size = sizeof (u32),
1927 .n_errors = TCP_N_ERROR,
1928 .error_strings = tcp_error_strings,
1929 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1931 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1932 foreach_tcp4_output_next
1935 .format_buffer = format_tcp_header,
1936 .format_trace = format_tcp_tx_trace,
1940 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1943 VLIB_REGISTER_NODE (tcp6_output_node) =
1945 .function = tcp6_output,
1946 .name = "tcp6-output",
1947 /* Takes a vector of packets. */
1948 .vector_size = sizeof (u32),
1949 .n_errors = TCP_N_ERROR,
1950 .error_strings = tcp_error_strings,
1951 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1953 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1954 foreach_tcp6_output_next
1957 .format_buffer = format_tcp_header,
1958 .format_trace = format_tcp_tx_trace,
1962 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1965 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1967 tcp_connection_t *tc;
1969 tc = (tcp_connection_t *) tconn;
1970 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1971 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1973 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1975 tc->rtt_ts = tcp_time_now ();
1976 tc->rtt_seq = tc->snd_nxt;
1981 typedef enum _tcp_reset_next
1983 TCP_RESET_NEXT_DROP,
1984 TCP_RESET_NEXT_IP_LOOKUP,
1988 #define foreach_tcp4_reset_next \
1989 _(DROP, "error-drop") \
1990 _(IP_LOOKUP, "ip4-lookup")
1992 #define foreach_tcp6_reset_next \
1993 _(DROP, "error-drop") \
1994 _(IP_LOOKUP, "ip6-lookup")
1997 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
1998 vlib_frame_t * from_frame, u8 is_ip4)
2000 u32 n_left_from, next_index, *from, *to_next;
2001 u32 my_thread_index = vm->thread_index;
2003 from = vlib_frame_vector_args (from_frame);
2004 n_left_from = from_frame->n_vectors;
2006 next_index = node->cached_next_index;
2008 while (n_left_from > 0)
2012 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
2014 while (n_left_from > 0 && n_left_to_next > 0)
2020 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
2027 n_left_to_next -= 1;
2029 b0 = vlib_get_buffer (vm, bi0);
2031 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
2032 my_thread_index, is_ip4))
2034 error0 = TCP_ERROR_LOOKUP_DROPS;
2035 next0 = TCP_RESET_NEXT_DROP;
2039 /* Prepare to send to IP lookup */
2040 vnet_buffer (b0)->sw_if_index[VLIB_TX] = 0;
2041 next0 = TCP_RESET_NEXT_IP_LOOKUP;
2044 b0->error = node->errors[error0];
2045 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
2046 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
2048 th0 = vlib_buffer_get_current (b0);
2050 th0 = ip4_next_header ((ip4_header_t *) th0);
2052 th0 = ip6_next_header ((ip6_header_t *) th0);
2053 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
2054 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
2057 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
2058 n_left_to_next, bi0, next0);
2060 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
2062 return from_frame->n_vectors;
2066 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2067 vlib_frame_t * from_frame)
2069 return tcp46_send_reset_inline (vm, node, from_frame, 1);
2073 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2074 vlib_frame_t * from_frame)
2076 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2080 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2081 .function = tcp4_send_reset,
2082 .name = "tcp4-reset",
2083 .vector_size = sizeof (u32),
2084 .n_errors = TCP_N_ERROR,
2085 .error_strings = tcp_error_strings,
2086 .n_next_nodes = TCP_RESET_N_NEXT,
2088 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2089 foreach_tcp4_reset_next
2092 .format_trace = format_tcp_tx_trace,
2096 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2099 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2100 .function = tcp6_send_reset,
2101 .name = "tcp6-reset",
2102 .vector_size = sizeof (u32),
2103 .n_errors = TCP_N_ERROR,
2104 .error_strings = tcp_error_strings,
2105 .n_next_nodes = TCP_RESET_N_NEXT,
2107 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2108 foreach_tcp6_reset_next
2111 .format_trace = format_tcp_tx_trace,
2115 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2118 * fd.io coding-style-patch-verification: ON
2121 * eval: (c-set-style "gnu")