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 (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
635 u32 *to_next, next_index;
638 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
641 /* Default FIB for now */
642 vnet_buffer (b)->sw_if_index[VLIB_TX] = 0;
644 /* Send to IP lookup */
645 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
646 f = vlib_get_frame_to_node (vm, next_index);
648 /* Enqueue the packet */
649 to_next = vlib_frame_vector_args (f);
652 vlib_put_frame_to_node (vm, next_index, f);
656 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
659 tcp_main_t *tm = vnet_get_tcp_main ();
660 u32 thread_index = vlib_get_thread_index ();
661 u32 *to_next, next_index;
664 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
667 /* Decide where to send the packet */
668 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
670 /* Initialize the trajectory trace, if configured */
671 if (VLIB_BUFFER_TRACE_TRAJECTORY > 0)
674 b->pre_data[1] = next_index;
677 /* Get frame to v4/6 output node */
678 f = tm->tx_frames[!is_ip4][thread_index];
681 f = vlib_get_frame_to_node (vm, next_index);
683 tm->tx_frames[!is_ip4][thread_index] = f;
685 to_next = vlib_frame_vector_args (f);
686 to_next[f->n_vectors] = bi;
688 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
690 vlib_put_frame_to_node (vm, next_index, f);
691 tm->tx_frames[!is_ip4][thread_index] = 0;
696 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
698 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
702 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
705 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
709 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
710 tcp_state_t state, u8 thread_index, u8 is_ip4)
715 ip4_address_t src_ip40, dst_ip40;
716 ip6_address_t src_ip60, dst_ip60;
717 u16 src_port, dst_port;
722 /* Find IP and TCP headers */
723 th0 = tcp_buffer_hdr (b0);
725 /* Save src and dst ip */
728 ih4 = vlib_buffer_get_current (b0);
729 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
730 src_ip40.as_u32 = ih4->src_address.as_u32;
731 dst_ip40.as_u32 = ih4->dst_address.as_u32;
735 ih6 = vlib_buffer_get_current (b0);
736 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
737 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
738 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
741 src_port = th0->src_port;
742 dst_port = th0->dst_port;
744 /* Try to determine what/why we're actually resetting */
745 if (state == TCP_STATE_CLOSED)
750 tmp = clib_net_to_host_u32 (th0->seq_number);
752 /* Got a SYN for no listener. */
753 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
754 ack = clib_host_to_net_u32 (tmp + 1);
759 flags = TCP_FLAG_RST;
760 seq = th0->ack_number;
764 tcp_reuse_buffer (vm, b0);
765 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
766 sizeof (tcp_header_t), flags, 0);
770 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
772 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
777 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
779 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
787 * Send reset without reusing existing buffer
789 * It extracts connection info out of original packet
792 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
796 tcp_main_t *tm = vnet_get_tcp_main ();
797 vlib_main_t *vm = vlib_get_main ();
798 u8 tcp_hdr_len, flags = 0;
799 tcp_header_t *th, *pkt_th;
801 ip4_header_t *ih4, *pkt_ih4;
802 ip6_header_t *ih6, *pkt_ih6;
804 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
807 b = vlib_get_buffer (vm, bi);
808 tcp_init_buffer (vm, b);
810 /* Make and write options */
811 tcp_hdr_len = sizeof (tcp_header_t);
815 pkt_ih4 = vlib_buffer_get_current (pkt);
816 pkt_th = ip4_next_header (pkt_ih4);
820 pkt_ih6 = vlib_buffer_get_current (pkt);
821 pkt_th = ip6_next_header (pkt_ih6);
824 if (tcp_ack (pkt_th))
826 flags = TCP_FLAG_RST;
827 seq = pkt_th->ack_number;
828 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
832 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
834 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
837 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
838 seq, ack, tcp_hdr_len, flags, 0);
840 /* Swap src and dst ip */
843 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
844 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
845 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
846 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
851 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
853 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
854 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
855 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
859 tcp_enqueue_to_ip_lookup (vm, b, bi, is_ip4);
860 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
864 * Build and set reset packet for connection
867 tcp_send_reset (tcp_connection_t * tc)
869 vlib_main_t *vm = vlib_get_main ();
870 tcp_main_t *tm = vnet_get_tcp_main ();
874 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
877 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
879 b = vlib_get_buffer (vm, bi);
880 tcp_init_buffer (vm, b);
882 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
883 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
884 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
885 flags = TCP_FLAG_RST;
886 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
887 tc->rcv_nxt, tcp_hdr_opts_len, flags,
889 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
890 ASSERT (opts_write_len == tc->snd_opts_len);
891 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
892 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
896 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
898 tcp_header_t *th = vlib_buffer_get_current (b);
899 vlib_main_t *vm = vlib_get_main ();
903 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
904 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
905 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
912 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
913 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
914 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
922 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
923 * The packet is not forwarded through tcpx_output to avoid doing lookups
924 * in the half_open pool.
927 tcp_send_syn (tcp_connection_t * tc)
931 tcp_main_t *tm = vnet_get_tcp_main ();
932 vlib_main_t *vm = vlib_get_main ();
934 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
937 b = vlib_get_buffer (vm, bi);
938 tcp_init_buffer (vm, b);
939 tcp_make_syn (tc, b);
941 /* Measure RTT with this */
942 tc->rtt_ts = tcp_time_now ();
943 tc->rtt_seq = tc->snd_nxt;
946 /* Set the connection establishment timer */
947 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
949 tcp_push_ip_hdr (tm, tc, b);
950 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
951 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
955 * Flush tx frame populated by retransmits and timer pops
958 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
960 if (tcp_main.tx_frames[!is_ip4][thread_index])
963 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
964 vlib_put_frame_to_node (vm, next_index,
965 tcp_main.tx_frames[!is_ip4][thread_index]);
966 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
971 * Flush both v4 and v6 tx frames for thread index
974 tcp_flush_frames_to_output (u8 thread_index)
976 vlib_main_t *vm = vlib_get_main ();
977 tcp_flush_frame_to_output (vm, thread_index, 1);
978 tcp_flush_frame_to_output (vm, thread_index, 0);
985 tcp_send_fin (tcp_connection_t * tc)
989 tcp_main_t *tm = vnet_get_tcp_main ();
990 vlib_main_t *vm = vlib_get_main ();
992 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
994 b = vlib_get_buffer (vm, bi);
995 /* buffer will be initialized by in tcp_make_fin */
996 tcp_make_fin (tc, b);
997 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
998 if (!(tc->flags & TCP_CONN_FINSNT))
1000 tc->flags |= TCP_CONN_FINSNT;
1001 tc->flags &= ~TCP_CONN_FINPNDG;
1004 tcp_retransmit_timer_force_update (tc);
1005 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1009 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1013 case TCP_STATE_ESTABLISHED:
1014 return TCP_FLAG_ACK;
1015 case TCP_STATE_SYN_RCVD:
1016 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1017 case TCP_STATE_SYN_SENT:
1018 return TCP_FLAG_SYN;
1019 case TCP_STATE_LAST_ACK:
1020 case TCP_STATE_FIN_WAIT_1:
1021 if (tc->snd_nxt + 1 < tc->snd_una_max)
1022 return TCP_FLAG_ACK;
1024 return TCP_FLAG_FIN;
1026 clib_warning ("Shouldn't be here!");
1032 * Push TCP header and update connection variables
1035 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1036 tcp_state_t next_state, u8 compute_opts)
1038 u32 advertise_wnd, data_len;
1039 u8 tcp_hdr_opts_len, opts_write_len, flags;
1042 data_len = b->current_length + b->total_length_not_including_first_buffer;
1043 ASSERT (!b->total_length_not_including_first_buffer
1044 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1045 vnet_buffer (b)->tcp.flags = 0;
1048 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1050 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1051 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1052 flags = tcp_make_state_flags (tc, next_state);
1054 /* Push header and options */
1055 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1056 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1058 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1060 ASSERT (opts_write_len == tc->snd_opts_len);
1061 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1064 * Update connection variables
1067 tc->snd_nxt += data_len;
1068 tc->rcv_las = tc->rcv_nxt;
1070 /* TODO this is updated in output as well ... */
1071 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1073 tc->snd_una_max = tc->snd_nxt;
1074 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1077 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1081 tcp_send_ack (tcp_connection_t * tc)
1083 tcp_main_t *tm = vnet_get_tcp_main ();
1084 vlib_main_t *vm = vlib_get_main ();
1090 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1092 b = vlib_get_buffer (vm, bi);
1094 /* Fill in the ACK */
1095 tcp_make_ack (tc, b);
1096 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1100 * Delayed ack timer handler
1102 * Sends delayed ACK when timer expires
1105 tcp_timer_delack_handler (u32 index)
1107 u32 thread_index = vlib_get_thread_index ();
1108 tcp_connection_t *tc;
1110 tc = tcp_connection_get (index, thread_index);
1111 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1116 * Build a retransmit segment
1118 * @return the number of bytes in the segment or 0 if there's nothing to
1122 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1123 u32 max_deq_bytes, vlib_buffer_t ** b)
1125 tcp_main_t *tm = vnet_get_tcp_main ();
1126 vlib_main_t *vm = vlib_get_main ();
1128 u32 start, bi, available_bytes, seg_size;
1131 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1132 ASSERT (max_deq_bytes != 0);
1135 * Make sure we can retransmit something
1137 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1138 ASSERT (available_bytes >= offset);
1139 available_bytes -= offset;
1140 if (!available_bytes)
1142 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1143 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1145 /* Start is beyond snd_congestion */
1146 start = tc->snd_una + offset;
1147 if (seq_geq (start, tc->snd_congestion))
1150 /* Don't overshoot snd_congestion */
1151 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1153 max_deq_bytes = tc->snd_congestion - start;
1154 if (max_deq_bytes == 0)
1158 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1163 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1166 * Allocate and fill in buffer(s)
1169 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1171 *b = vlib_get_buffer (vm, bi);
1172 data = tcp_init_buffer (vm, *b);
1174 /* Easy case, buffer size greater than mss */
1175 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1177 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1179 ASSERT (n_bytes == max_deq_bytes);
1180 b[0]->current_length = n_bytes;
1181 tcp_push_hdr_i (tc, *b, tc->state, 0);
1183 /* Split mss into multiple buffers */
1186 u32 chain_bi = ~0, n_bufs_per_seg;
1187 u32 thread_index = vlib_get_thread_index ();
1188 u16 n_peeked, len_to_deq, available_bufs;
1189 vlib_buffer_t *chain_b, *prev_b;
1192 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1194 /* Make sure we have enough buffers */
1195 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1196 if (n_bufs_per_seg > available_bufs)
1198 if (tcp_alloc_tx_buffers (tm, thread_index,
1199 VLIB_FRAME_SIZE - available_bufs))
1201 tcp_return_buffer (tm);
1207 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1208 tm->bytes_per_buffer -
1210 b[0]->current_length = n_bytes;
1211 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1212 b[0]->total_length_not_including_first_buffer = 0;
1213 max_deq_bytes -= n_bytes;
1216 for (i = 1; i < n_bufs_per_seg; i++)
1219 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1220 tcp_get_free_buffer_index (tm, &chain_bi);
1221 ASSERT (chain_bi != (u32) ~ 0);
1222 chain_b = vlib_get_buffer (vm, chain_bi);
1223 chain_b->current_data = 0;
1224 data = vlib_buffer_get_current (chain_b);
1225 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1226 offset + n_bytes, len_to_deq);
1227 ASSERT (n_peeked == len_to_deq);
1228 n_bytes += n_peeked;
1229 chain_b->current_length = n_peeked;
1230 chain_b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
1231 chain_b->next_buffer = 0;
1233 /* update previous buffer */
1234 prev_b->next_buffer = chain_bi;
1235 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1237 max_deq_bytes -= n_peeked;
1238 b[0]->total_length_not_including_first_buffer += n_peeked;
1241 tcp_push_hdr_i (tc, *b, tc->state, 0);
1244 ASSERT (n_bytes > 0);
1245 ASSERT (((*b)->current_data + (*b)->current_length) <=
1246 tm->bytes_per_buffer);
1248 if (tcp_in_fastrecovery (tc))
1249 tc->snd_rxt_bytes += n_bytes;
1252 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1257 * Reset congestion control, switch cwnd to loss window and try again.
1260 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1262 tc->prev_ssthresh = tc->ssthresh;
1263 tc->prev_cwnd = tc->cwnd;
1265 /* Cleanly recover cc (also clears up fast retransmit) */
1266 if (tcp_in_fastrecovery (tc))
1267 tcp_cc_fastrecovery_exit (tc);
1269 /* Start again from the beginning */
1270 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1271 tc->cwnd = tcp_loss_wnd (tc);
1272 tc->snd_congestion = tc->snd_una_max;
1274 tcp_recovery_on (tc);
1278 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1280 tcp_main_t *tm = vnet_get_tcp_main ();
1281 vlib_main_t *vm = vlib_get_main ();
1282 u32 thread_index = vlib_get_thread_index ();
1283 tcp_connection_t *tc;
1284 vlib_buffer_t *b = 0;
1289 tc = tcp_half_open_connection_get (index);
1290 /* Note: the connection may have transitioned to ESTABLISHED... */
1291 if (PREDICT_FALSE (tc == 0))
1293 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1297 tc = tcp_connection_get (index, thread_index);
1298 /* Note: the connection may have been closed and pool_put */
1299 if (PREDICT_FALSE (tc == 0))
1301 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1304 if (tc->state >= TCP_STATE_ESTABLISHED)
1306 /* Lost FIN, retransmit and return */
1307 if (tcp_is_lost_fin (tc))
1313 /* We're not in recovery so make sure rto_boff is 0 */
1314 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1317 tcp_update_rto (tc);
1320 /* Increment RTO backoff (also equal to number of retries) and go back
1321 * to first un-acked byte */
1323 tc->snd_nxt = tc->snd_una;
1325 /* First retransmit timeout */
1326 if (tc->rto_boff == 1)
1327 tcp_rtx_timeout_cc (tc);
1329 /* Exponential backoff */
1330 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1332 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1334 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1335 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1337 /* TODO be less aggressive about this */
1338 scoreboard_clear (&tc->sack_sb);
1343 if (tc->snd_una == tc->snd_una_max)
1345 ASSERT (tc->rto_boff > 1 && tc->snd_una == tc->snd_congestion);
1346 clib_warning ("retransmit fail: %U", format_tcp_connection, tc, 2);
1347 /* Try again eventually */
1348 tcp_retransmit_timer_set (tc);
1352 bi = vlib_get_buffer_index (vm, b);
1354 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1355 if (tc->rto_boff == 1)
1356 tc->snd_rxt_ts = tcp_time_now ();
1358 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1359 tcp_retransmit_timer_update (tc);
1361 /* Retransmit for SYN */
1362 else if (tc->state == TCP_STATE_SYN_SENT)
1364 /* Half-open connection actually moved to established but we were
1365 * waiting for syn retransmit to pop to call cleanup from the right
1367 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1369 if (tcp_half_open_connection_cleanup (tc))
1371 clib_warning ("could not remove half-open connection");
1377 /* Try without increasing RTO a number of times. If this fails,
1378 * start growing RTO exponentially */
1380 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1381 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1383 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1386 b = vlib_get_buffer (vm, bi);
1387 tcp_init_buffer (vm, b);
1388 tcp_make_syn (tc, b);
1391 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1393 /* This goes straight to ipx_lookup. Retransmit timer set already */
1394 tcp_push_ip_hdr (tm, tc, b);
1395 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
1397 /* Retransmit SYN-ACK */
1398 else if (tc->state == TCP_STATE_SYN_RCVD)
1401 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1404 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1407 b = vlib_get_buffer (vm, bi);
1408 tcp_make_synack (tc, b);
1409 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1411 /* Retransmit timer already updated, just enqueue to output */
1412 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1416 ASSERT (tc->state == TCP_STATE_CLOSED);
1417 clib_warning ("connection closed ...");
1423 tcp_timer_retransmit_handler (u32 index)
1425 tcp_timer_retransmit_handler_i (index, 0);
1429 tcp_timer_retransmit_syn_handler (u32 index)
1431 tcp_timer_retransmit_handler_i (index, 1);
1435 * Got 0 snd_wnd from peer, try to do something about it.
1439 tcp_timer_persist_handler (u32 index)
1441 tcp_main_t *tm = vnet_get_tcp_main ();
1442 vlib_main_t *vm = vlib_get_main ();
1443 u32 thread_index = vlib_get_thread_index ();
1444 tcp_connection_t *tc;
1446 u32 bi, old_snd_nxt, max_snd_bytes, available_bytes, offset;
1450 tc = tcp_connection_get_if_valid (index, thread_index);
1455 /* Make sure timer handle is set to invalid */
1456 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1458 /* Problem already solved or worse */
1459 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1460 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1463 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1464 offset = tc->snd_una_max - tc->snd_una;
1466 /* Reprogram persist if no new bytes available to send. We may have data
1468 if (!available_bytes)
1470 tcp_persist_timer_set (tc);
1474 if (available_bytes <= offset)
1476 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1480 /* Increment RTO backoff */
1482 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1485 * Try to force the first unsent segment (or buffer)
1487 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1489 b = vlib_get_buffer (vm, bi);
1490 data = tcp_init_buffer (vm, b);
1492 tcp_validate_txf_size (tc, offset);
1493 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1494 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1495 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1497 b->current_length = n_bytes;
1498 ASSERT (n_bytes != 0 && (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1
1499 || tcp_timer_is_active (tc,
1500 TCP_TIMER_RETRANSMIT)));
1502 /* Allow updating of snd_una_max but don't update snd_nxt */
1503 old_snd_nxt = tc->snd_nxt;
1504 tcp_push_hdr_i (tc, b, tc->state, 0);
1505 tc->snd_nxt = old_snd_nxt;
1506 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1508 /* Just sent new data, enable retransmit */
1509 tcp_retransmit_timer_update (tc);
1513 * Retransmit first unacked segment
1516 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1518 vlib_main_t *vm = vlib_get_main ();
1520 u32 bi, old_snd_nxt, n_bytes;
1522 old_snd_nxt = tc->snd_nxt;
1523 tc->snd_nxt = tc->snd_una;
1525 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1526 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1529 bi = vlib_get_buffer_index (vm, b);
1530 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1532 tc->snd_nxt = old_snd_nxt;
1536 * Do fast retransmit with SACKs
1539 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1541 vlib_main_t *vm = vlib_get_main ();
1542 u32 n_written = 0, offset, max_bytes;
1543 vlib_buffer_t *b = 0;
1544 sack_scoreboard_hole_t *hole;
1545 sack_scoreboard_t *sb;
1546 u32 bi, old_snd_nxt;
1548 u8 snd_limited = 0, can_rescue = 0;
1550 ASSERT (tcp_in_fastrecovery (tc));
1551 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1553 old_snd_nxt = tc->snd_nxt;
1555 snd_space = tcp_available_snd_space (tc);
1557 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1558 while (hole && snd_space > 0)
1560 hole = scoreboard_next_rxt_hole (sb, hole,
1561 tcp_fastrecovery_sent_1_smss (tc),
1562 &can_rescue, &snd_limited);
1565 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1566 || seq_gt (sb->rescue_rxt,
1567 tc->snd_congestion)))
1570 /* If rescue rxt undefined or less than snd_una then one segment of
1571 * up to SMSS octets that MUST include the highest outstanding
1572 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1573 * RecoveryPoint. HighRxt MUST NOT be updated.
1575 max_bytes = clib_min (tc->snd_mss,
1576 tc->snd_congestion - tc->snd_una);
1577 max_bytes = clib_min (max_bytes, snd_space);
1578 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1579 sb->rescue_rxt = tc->snd_congestion;
1580 tc->snd_nxt = tc->snd_una + offset;
1581 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1584 bi = vlib_get_buffer_index (vm, b);
1585 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1589 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1590 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1593 offset = sb->high_rxt - tc->snd_una;
1594 tc->snd_nxt = sb->high_rxt;
1595 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1597 /* Nothing left to retransmit */
1601 bi = vlib_get_buffer_index (vm, b);
1602 sb->high_rxt += n_written;
1603 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1604 ASSERT (n_written <= snd_space);
1605 snd_space -= n_written;
1608 /* If window allows, send 1 SMSS of new data */
1609 tc->snd_nxt = old_snd_nxt;
1613 * Fast retransmit without SACK info
1616 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1618 vlib_main_t *vm = vlib_get_main ();
1619 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1623 ASSERT (tcp_in_fastrecovery (tc));
1624 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1626 /* Start resending from first un-acked segment */
1627 old_snd_nxt = tc->snd_nxt;
1628 tc->snd_nxt = tc->snd_una;
1629 snd_space = tcp_available_snd_space (tc);
1631 while (snd_space > 0)
1633 offset += n_written;
1634 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1636 /* Nothing left to retransmit */
1640 bi = vlib_get_buffer_index (vm, b);
1641 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1642 snd_space -= n_written;
1645 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1646 tc->snd_nxt = old_snd_nxt;
1650 * Do fast retransmit
1653 tcp_fast_retransmit (tcp_connection_t * tc)
1655 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1656 && scoreboard_first_hole (&tc->sack_sb))
1657 tcp_fast_retransmit_sack (tc);
1659 tcp_fast_retransmit_no_sack (tc);
1663 tcp_session_has_ooo_data (tcp_connection_t * tc)
1665 stream_session_t *s =
1666 stream_session_get (tc->c_s_index, tc->c_thread_index);
1667 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1671 tcp46_output_inline (vlib_main_t * vm,
1672 vlib_node_runtime_t * node,
1673 vlib_frame_t * from_frame, int is_ip4)
1675 u32 n_left_from, next_index, *from, *to_next;
1676 u32 my_thread_index = vm->thread_index;
1678 from = vlib_frame_vector_args (from_frame);
1679 n_left_from = from_frame->n_vectors;
1680 next_index = node->cached_next_index;
1681 tcp_set_time_now (my_thread_index);
1683 while (n_left_from > 0)
1687 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1689 while (n_left_from > 0 && n_left_to_next > 0)
1693 tcp_connection_t *tc0;
1695 tcp_header_t *th0 = 0;
1696 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1703 n_left_to_next -= 1;
1705 b0 = vlib_get_buffer (vm, bi0);
1706 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1708 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1710 error0 = TCP_ERROR_INVALID_CONNECTION;
1711 next0 = TCP_OUTPUT_NEXT_DROP;
1715 th0 = vlib_buffer_get_current (b0);
1716 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1720 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1721 IP_PROTOCOL_TCP, 1);
1722 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1723 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1729 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1730 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1731 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1732 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1733 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1737 /* Filter out DUPACKs if there are no OOO segments left */
1739 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1741 if (!tcp_session_has_ooo_data (tc0))
1743 error0 = TCP_ERROR_FILTERED_DUPACKS;
1744 next0 = TCP_OUTPUT_NEXT_DROP;
1749 /* Stop DELACK timer and fix flags */
1750 tc0->flags &= ~(TCP_CONN_SNDACK);
1751 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1753 /* If not retransmitting
1754 * 1) update snd_una_max (SYN, SYNACK, FIN)
1755 * 2) If we're not tracking an ACK, start tracking */
1756 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1758 tc0->snd_una_max = tc0->snd_nxt;
1759 if (tc0->rtt_ts == 0)
1761 tc0->rtt_ts = tcp_time_now ();
1762 tc0->rtt_seq = tc0->snd_nxt;
1766 /* Set the retransmit timer if not set already and not
1767 * doing a pure ACK */
1768 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1769 && tc0->snd_nxt != tc0->snd_una)
1771 tcp_retransmit_timer_set (tc0);
1776 /* Make sure we haven't lost route to our peer */
1777 if (PREDICT_FALSE (tc0->last_fib_check
1778 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1781 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1783 tc0->last_fib_check = tc0->snd_opts.tsval;
1787 clib_warning ("lost connection to peer");
1788 tcp_connection_reset (tc0);
1793 /* Use pre-computed dpo to set next node */
1794 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1795 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1798 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1799 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1801 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1803 b0->error = node->errors[error0];
1804 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1806 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1809 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1813 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1815 clib_memcpy (&t0->tcp_connection, tc0,
1816 sizeof (t0->tcp_connection));
1819 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1820 n_left_to_next, bi0, next0);
1823 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1826 return from_frame->n_vectors;
1830 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1831 vlib_frame_t * from_frame)
1833 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1837 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1838 vlib_frame_t * from_frame)
1840 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1844 VLIB_REGISTER_NODE (tcp4_output_node) =
1846 .function = tcp4_output,.name = "tcp4-output",
1847 /* Takes a vector of packets. */
1848 .vector_size = sizeof (u32),
1849 .n_errors = TCP_N_ERROR,
1850 .error_strings = tcp_error_strings,
1851 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1853 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1854 foreach_tcp4_output_next
1857 .format_buffer = format_tcp_header,
1858 .format_trace = format_tcp_tx_trace,
1862 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1865 VLIB_REGISTER_NODE (tcp6_output_node) =
1867 .function = tcp6_output,
1868 .name = "tcp6-output",
1869 /* Takes a vector of packets. */
1870 .vector_size = sizeof (u32),
1871 .n_errors = TCP_N_ERROR,
1872 .error_strings = tcp_error_strings,
1873 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1875 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1876 foreach_tcp6_output_next
1879 .format_buffer = format_tcp_header,
1880 .format_trace = format_tcp_tx_trace,
1884 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1887 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1889 tcp_connection_t *tc;
1891 tc = (tcp_connection_t *) tconn;
1892 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1893 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1895 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1897 tc->rtt_ts = tcp_time_now ();
1898 tc->rtt_seq = tc->snd_nxt;
1903 typedef enum _tcp_reset_next
1905 TCP_RESET_NEXT_DROP,
1906 TCP_RESET_NEXT_IP_LOOKUP,
1910 #define foreach_tcp4_reset_next \
1911 _(DROP, "error-drop") \
1912 _(IP_LOOKUP, "ip4-lookup")
1914 #define foreach_tcp6_reset_next \
1915 _(DROP, "error-drop") \
1916 _(IP_LOOKUP, "ip6-lookup")
1919 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
1920 vlib_frame_t * from_frame, u8 is_ip4)
1922 u32 n_left_from, next_index, *from, *to_next;
1923 u32 my_thread_index = vm->thread_index;
1925 from = vlib_frame_vector_args (from_frame);
1926 n_left_from = from_frame->n_vectors;
1928 next_index = node->cached_next_index;
1930 while (n_left_from > 0)
1934 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1936 while (n_left_from > 0 && n_left_to_next > 0)
1942 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
1949 n_left_to_next -= 1;
1951 b0 = vlib_get_buffer (vm, bi0);
1953 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
1954 my_thread_index, is_ip4))
1956 error0 = TCP_ERROR_LOOKUP_DROPS;
1957 next0 = TCP_RESET_NEXT_DROP;
1961 /* Prepare to send to IP lookup */
1962 vnet_buffer (b0)->sw_if_index[VLIB_TX] = 0;
1963 next0 = TCP_RESET_NEXT_IP_LOOKUP;
1966 b0->error = node->errors[error0];
1967 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1968 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1970 th0 = vlib_buffer_get_current (b0);
1972 th0 = ip4_next_header ((ip4_header_t *) th0);
1974 th0 = ip6_next_header ((ip6_header_t *) th0);
1975 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1976 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1979 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1980 n_left_to_next, bi0, next0);
1982 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1984 return from_frame->n_vectors;
1988 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
1989 vlib_frame_t * from_frame)
1991 return tcp46_send_reset_inline (vm, node, from_frame, 1);
1995 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
1996 vlib_frame_t * from_frame)
1998 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2002 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2003 .function = tcp4_send_reset,
2004 .name = "tcp4-reset",
2005 .vector_size = sizeof (u32),
2006 .n_errors = TCP_N_ERROR,
2007 .error_strings = tcp_error_strings,
2008 .n_next_nodes = TCP_RESET_N_NEXT,
2010 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2011 foreach_tcp4_reset_next
2014 .format_trace = format_tcp_tx_trace,
2018 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2021 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2022 .function = tcp6_send_reset,
2023 .name = "tcp6-reset",
2024 .vector_size = sizeof (u32),
2025 .n_errors = TCP_N_ERROR,
2026 .error_strings = tcp_error_strings,
2027 .n_next_nodes = TCP_RESET_N_NEXT,
2029 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2030 foreach_tcp6_reset_next
2033 .format_trace = format_tcp_tx_trace,
2037 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2040 * fd.io coding-style-patch-verification: ON
2043 * eval: (c-set-style "gnu")