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 u32 current_length = vec_len (tm->tx_buffers[thread_index]);
444 vec_validate (tm->tx_buffers[thread_index],
445 current_length + n_free_buffers - 1);
446 _vec_len (tm->tx_buffers[thread_index]) = current_length
447 + vlib_buffer_alloc (vlib_get_main (),
448 &tm->tx_buffers[thread_index][current_length],
450 /* buffer shortage, report failure */
451 if (vec_len (tm->tx_buffers[thread_index]) == 0)
453 clib_warning ("out of buffers");
460 tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx)
463 u32 thread_index = vlib_get_thread_index ();
464 if (PREDICT_FALSE (vec_len (tm->tx_buffers[thread_index]) == 0))
466 if (tcp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE))
469 my_tx_buffers = tm->tx_buffers[thread_index];
470 *bidx = my_tx_buffers[vec_len (my_tx_buffers) - 1];
471 _vec_len (my_tx_buffers) -= 1;
476 tcp_return_buffer (tcp_main_t * tm)
478 _vec_len (tm->tx_buffers[vlib_get_thread_index ()]) += 1;
482 tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
484 if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
485 vlib_buffer_free_one (vm, b->next_buffer);
486 /* Zero all flags but free list index and trace flag */
487 b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1;
489 b->current_length = 0;
490 b->total_length_not_including_first_buffer = 0;
491 vnet_buffer (b)->tcp.flags = 0;
493 /* Leave enough space for headers */
494 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
498 tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
500 ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
501 b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
502 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
503 b->total_length_not_including_first_buffer = 0;
504 vnet_buffer (b)->tcp.flags = 0;
506 /* Leave enough space for headers */
507 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
514 tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
517 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
518 u8 tcp_opts_len, tcp_hdr_opts_len;
522 wnd = tcp_window_to_advertise (tc, state);
524 /* Make and write options */
525 tcp_opts_len = tcp_make_established_options (tc, snd_opts);
526 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
528 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
529 tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
531 tcp_options_write ((u8 *) (th + 1), snd_opts);
532 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
536 * Convert buffer to ACK
539 tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
541 vlib_main_t *vm = vlib_get_main ();
543 tcp_reuse_buffer (vm, b);
544 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
545 TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
546 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
547 tc->rcv_las = tc->rcv_nxt;
551 * Convert buffer to FIN-ACK
554 tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
556 vlib_main_t *vm = vlib_get_main ();
559 tcp_reuse_buffer (vm, b);
561 flags = TCP_FLAG_FIN | TCP_FLAG_ACK;
562 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags);
564 /* Reset flags, make sure ack is sent */
565 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
569 * Convert buffer to SYN
572 tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
574 u8 tcp_hdr_opts_len, tcp_opts_len;
577 tcp_options_t snd_opts;
579 initial_wnd = tcp_initial_window_to_advertise (tc);
581 /* Make and write options */
582 memset (&snd_opts, 0, sizeof (snd_opts));
583 tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale);
584 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
586 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
587 tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
589 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
590 tcp_options_write ((u8 *) (th + 1), &snd_opts);
592 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
593 tc->rto * TCP_TO_TIMER_TICK);
597 * Convert buffer to SYN-ACK
600 tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
602 vlib_main_t *vm = vlib_get_main ();
603 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
604 u8 tcp_opts_len, tcp_hdr_opts_len;
608 memset (snd_opts, 0, sizeof (*snd_opts));
609 tcp_reuse_buffer (vm, b);
611 initial_wnd = tcp_initial_window_to_advertise (tc);
612 tcp_opts_len = tcp_make_synack_options (tc, snd_opts);
613 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
615 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
616 tc->rcv_nxt, tcp_hdr_opts_len,
617 TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd);
618 tcp_options_write ((u8 *) (th + 1), snd_opts);
620 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
621 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
623 /* Init retransmit timer. Use update instead of set because of
625 tcp_retransmit_timer_force_update (tc);
626 TCP_EVT_DBG (TCP_EVT_SYNACK_SENT, tc);
630 tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
633 u32 *to_next, next_index;
636 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
639 /* Default FIB for now */
640 vnet_buffer (b)->sw_if_index[VLIB_TX] = 0;
642 /* Send to IP lookup */
643 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
644 f = vlib_get_frame_to_node (vm, next_index);
646 /* Enqueue the packet */
647 to_next = vlib_frame_vector_args (f);
650 vlib_put_frame_to_node (vm, next_index, f);
654 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
657 tcp_main_t *tm = vnet_get_tcp_main ();
658 u32 thread_index = vlib_get_thread_index ();
659 u32 *to_next, next_index;
662 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
665 /* Decide where to send the packet */
666 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
668 /* Initialize the trajectory trace, if configured */
669 if (VLIB_BUFFER_TRACE_TRAJECTORY > 0)
672 b->pre_data[1] = next_index;
675 /* Get frame to v4/6 output node */
676 f = tm->tx_frames[!is_ip4][thread_index];
679 f = vlib_get_frame_to_node (vm, next_index);
681 tm->tx_frames[!is_ip4][thread_index] = f;
683 to_next = vlib_frame_vector_args (f);
684 to_next[f->n_vectors] = bi;
686 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
688 vlib_put_frame_to_node (vm, next_index, f);
689 tm->tx_frames[!is_ip4][thread_index] = 0;
694 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
696 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
700 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
703 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
707 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
708 tcp_state_t state, u8 thread_index, u8 is_ip4)
713 ip4_address_t src_ip40, dst_ip40;
714 ip6_address_t src_ip60, dst_ip60;
715 u16 src_port, dst_port;
720 /* Find IP and TCP headers */
721 th0 = tcp_buffer_hdr (b0);
723 /* Save src and dst ip */
726 ih4 = vlib_buffer_get_current (b0);
727 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
728 src_ip40.as_u32 = ih4->src_address.as_u32;
729 dst_ip40.as_u32 = ih4->dst_address.as_u32;
733 ih6 = vlib_buffer_get_current (b0);
734 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
735 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
736 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
739 src_port = th0->src_port;
740 dst_port = th0->dst_port;
742 /* Try to determine what/why we're actually resetting */
743 if (state == TCP_STATE_CLOSED)
748 tmp = clib_net_to_host_u32 (th0->seq_number);
750 /* Got a SYN for no listener. */
751 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
752 ack = clib_host_to_net_u32 (tmp + 1);
757 flags = TCP_FLAG_RST;
758 seq = th0->ack_number;
762 tcp_reuse_buffer (vm, b0);
763 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
764 sizeof (tcp_header_t), flags, 0);
768 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
770 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
775 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
777 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
785 * Send reset without reusing existing buffer
787 * It extracts connection info out of original packet
790 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
794 tcp_main_t *tm = vnet_get_tcp_main ();
795 vlib_main_t *vm = vlib_get_main ();
796 u8 tcp_hdr_len, flags = 0;
797 tcp_header_t *th, *pkt_th;
799 ip4_header_t *ih4, *pkt_ih4;
800 ip6_header_t *ih6, *pkt_ih6;
802 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
805 b = vlib_get_buffer (vm, bi);
806 tcp_init_buffer (vm, b);
808 /* Make and write options */
809 tcp_hdr_len = sizeof (tcp_header_t);
813 pkt_ih4 = vlib_buffer_get_current (pkt);
814 pkt_th = ip4_next_header (pkt_ih4);
818 pkt_ih6 = vlib_buffer_get_current (pkt);
819 pkt_th = ip6_next_header (pkt_ih6);
822 if (tcp_ack (pkt_th))
824 flags = TCP_FLAG_RST;
825 seq = pkt_th->ack_number;
826 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
830 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
832 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
835 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
836 seq, ack, tcp_hdr_len, flags, 0);
838 /* Swap src and dst ip */
841 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
842 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
843 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
844 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
849 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
851 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
852 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
853 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
857 tcp_enqueue_to_ip_lookup (vm, b, bi, is_ip4);
858 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
862 * Build and set reset packet for connection
865 tcp_send_reset (tcp_connection_t * tc)
867 vlib_main_t *vm = vlib_get_main ();
868 tcp_main_t *tm = vnet_get_tcp_main ();
872 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
875 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
877 b = vlib_get_buffer (vm, bi);
878 tcp_init_buffer (vm, b);
880 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
881 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
882 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
883 flags = TCP_FLAG_RST;
884 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
885 tc->rcv_nxt, tcp_hdr_opts_len, flags,
887 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
888 ASSERT (opts_write_len == tc->snd_opts_len);
889 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
890 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
894 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
896 tcp_header_t *th = vlib_buffer_get_current (b);
897 vlib_main_t *vm = vlib_get_main ();
901 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
902 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
903 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
910 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
911 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
912 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
920 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
921 * The packet is not forwarded through tcpx_output to avoid doing lookups
922 * in the half_open pool.
925 tcp_send_syn (tcp_connection_t * tc)
929 tcp_main_t *tm = vnet_get_tcp_main ();
930 vlib_main_t *vm = vlib_get_main ();
932 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
935 b = vlib_get_buffer (vm, bi);
936 tcp_init_buffer (vm, b);
937 tcp_make_syn (tc, b);
939 /* Measure RTT with this */
940 tc->rtt_ts = tcp_time_now ();
941 tc->rtt_seq = tc->snd_nxt;
944 /* Set the connection establishment timer */
945 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
947 tcp_push_ip_hdr (tm, tc, b);
948 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
949 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
953 * Flush tx frame populated by retransmits and timer pops
956 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
958 if (tcp_main.tx_frames[!is_ip4][thread_index])
961 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
962 vlib_put_frame_to_node (vm, next_index,
963 tcp_main.tx_frames[!is_ip4][thread_index]);
964 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
969 * Flush both v4 and v6 tx frames for thread index
972 tcp_flush_frames_to_output (u8 thread_index)
974 vlib_main_t *vm = vlib_get_main ();
975 tcp_flush_frame_to_output (vm, thread_index, 1);
976 tcp_flush_frame_to_output (vm, thread_index, 0);
983 tcp_send_fin (tcp_connection_t * tc)
987 tcp_main_t *tm = vnet_get_tcp_main ();
988 vlib_main_t *vm = vlib_get_main ();
990 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
992 b = vlib_get_buffer (vm, bi);
993 /* buffer will be initialized by in tcp_make_fin */
994 tcp_make_fin (tc, b);
995 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
996 if (!(tc->flags & TCP_CONN_FINSNT))
998 tc->flags |= TCP_CONN_FINSNT;
999 tc->flags &= ~TCP_CONN_FINPNDG;
1002 tcp_retransmit_timer_force_update (tc);
1003 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1007 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1011 case TCP_STATE_ESTABLISHED:
1012 return TCP_FLAG_ACK;
1013 case TCP_STATE_SYN_RCVD:
1014 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1015 case TCP_STATE_SYN_SENT:
1016 return TCP_FLAG_SYN;
1017 case TCP_STATE_LAST_ACK:
1018 case TCP_STATE_FIN_WAIT_1:
1019 if (tc->snd_nxt + 1 < tc->snd_una_max)
1020 return TCP_FLAG_ACK;
1022 return TCP_FLAG_FIN;
1024 clib_warning ("Shouldn't be here!");
1030 * Push TCP header and update connection variables
1033 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1034 tcp_state_t next_state, u8 compute_opts)
1036 u32 advertise_wnd, data_len;
1037 u8 tcp_hdr_opts_len, opts_write_len, flags;
1040 data_len = b->current_length + b->total_length_not_including_first_buffer;
1041 ASSERT (!b->total_length_not_including_first_buffer
1042 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1043 vnet_buffer (b)->tcp.flags = 0;
1046 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1048 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1049 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1050 flags = tcp_make_state_flags (tc, next_state);
1052 /* Push header and options */
1053 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1054 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1056 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1058 ASSERT (opts_write_len == tc->snd_opts_len);
1059 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1062 * Update connection variables
1065 tc->snd_nxt += data_len;
1066 tc->rcv_las = tc->rcv_nxt;
1068 /* TODO this is updated in output as well ... */
1069 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1071 tc->snd_una_max = tc->snd_nxt;
1072 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1075 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1079 tcp_send_ack (tcp_connection_t * tc)
1081 tcp_main_t *tm = vnet_get_tcp_main ();
1082 vlib_main_t *vm = vlib_get_main ();
1088 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1090 b = vlib_get_buffer (vm, bi);
1092 /* Fill in the ACK */
1093 tcp_make_ack (tc, b);
1094 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1098 * Delayed ack timer handler
1100 * Sends delayed ACK when timer expires
1103 tcp_timer_delack_handler (u32 index)
1105 u32 thread_index = vlib_get_thread_index ();
1106 tcp_connection_t *tc;
1108 tc = tcp_connection_get (index, thread_index);
1109 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1114 * Build a retransmit segment
1116 * @return the number of bytes in the segment or 0 if there's nothing to
1120 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1121 u32 max_deq_bytes, vlib_buffer_t ** b)
1123 tcp_main_t *tm = vnet_get_tcp_main ();
1124 vlib_main_t *vm = vlib_get_main ();
1126 u32 start, bi, available_bytes, seg_size;
1129 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1130 ASSERT (max_deq_bytes != 0);
1133 * Make sure we can retransmit something
1135 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1136 ASSERT (available_bytes >= offset);
1137 available_bytes -= offset;
1138 if (!available_bytes)
1140 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1141 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1143 /* Start is beyond snd_congestion */
1144 start = tc->snd_una + offset;
1145 if (seq_geq (start, tc->snd_congestion))
1148 /* Don't overshoot snd_congestion */
1149 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1151 max_deq_bytes = tc->snd_congestion - start;
1152 if (max_deq_bytes == 0)
1156 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1161 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1164 * Allocate and fill in buffer(s)
1167 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1169 *b = vlib_get_buffer (vm, bi);
1170 data = tcp_init_buffer (vm, *b);
1172 /* Easy case, buffer size greater than mss */
1173 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1175 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1177 ASSERT (n_bytes == max_deq_bytes);
1178 b[0]->current_length = n_bytes;
1179 tcp_push_hdr_i (tc, *b, tc->state, 0);
1181 /* Split mss into multiple buffers */
1184 u32 chain_bi = ~0, n_bufs_per_seg;
1185 u32 thread_index = vlib_get_thread_index ();
1186 u16 n_peeked, len_to_deq, available_bufs;
1187 vlib_buffer_t *chain_b, *prev_b;
1190 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1192 /* Make sure we have enough buffers */
1193 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1194 if (n_bufs_per_seg > available_bufs)
1196 if (tcp_alloc_tx_buffers (tm, thread_index,
1197 VLIB_FRAME_SIZE - available_bufs))
1199 tcp_return_buffer (tm);
1205 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1206 tm->bytes_per_buffer -
1208 b[0]->current_length = n_bytes;
1209 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1210 b[0]->total_length_not_including_first_buffer = 0;
1211 max_deq_bytes -= n_bytes;
1214 for (i = 1; i < n_bufs_per_seg; i++)
1217 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1218 tcp_get_free_buffer_index (tm, &chain_bi);
1219 ASSERT (chain_bi != (u32) ~ 0);
1220 chain_b = vlib_get_buffer (vm, chain_bi);
1221 chain_b->current_data = 0;
1222 data = vlib_buffer_get_current (chain_b);
1223 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1224 offset + n_bytes, len_to_deq);
1225 ASSERT (n_peeked == len_to_deq);
1226 n_bytes += n_peeked;
1227 chain_b->current_length = n_peeked;
1228 chain_b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK;
1229 chain_b->next_buffer = 0;
1231 /* update previous buffer */
1232 prev_b->next_buffer = chain_bi;
1233 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1235 max_deq_bytes -= n_peeked;
1236 b[0]->total_length_not_including_first_buffer += n_peeked;
1239 tcp_push_hdr_i (tc, *b, tc->state, 0);
1242 ASSERT (n_bytes > 0);
1243 ASSERT (((*b)->current_data + (*b)->current_length) <=
1244 tm->bytes_per_buffer);
1246 if (tcp_in_fastrecovery (tc))
1247 tc->snd_rxt_bytes += n_bytes;
1250 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1255 * Reset congestion control, switch cwnd to loss window and try again.
1258 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1260 tc->prev_ssthresh = tc->ssthresh;
1261 tc->prev_cwnd = tc->cwnd;
1263 /* Cleanly recover cc (also clears up fast retransmit) */
1264 if (tcp_in_fastrecovery (tc))
1265 tcp_cc_fastrecovery_exit (tc);
1267 /* Start again from the beginning */
1268 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1269 tc->cwnd = tcp_loss_wnd (tc);
1270 tc->snd_congestion = tc->snd_una_max;
1272 tcp_recovery_on (tc);
1276 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1278 tcp_main_t *tm = vnet_get_tcp_main ();
1279 vlib_main_t *vm = vlib_get_main ();
1280 u32 thread_index = vlib_get_thread_index ();
1281 tcp_connection_t *tc;
1282 vlib_buffer_t *b = 0;
1287 tc = tcp_half_open_connection_get (index);
1288 /* Note: the connection may have transitioned to ESTABLISHED... */
1289 if (PREDICT_FALSE (tc == 0))
1291 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1295 tc = tcp_connection_get (index, thread_index);
1296 /* Note: the connection may have been closed and pool_put */
1297 if (PREDICT_FALSE (tc == 0))
1299 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1302 if (tc->state >= TCP_STATE_ESTABLISHED)
1304 /* Lost FIN, retransmit and return */
1305 if (tcp_is_lost_fin (tc))
1311 /* We're not in recovery so make sure rto_boff is 0 */
1312 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1315 tcp_update_rto (tc);
1318 /* Increment RTO backoff (also equal to number of retries) and go back
1319 * to first un-acked byte */
1321 tc->snd_nxt = tc->snd_una;
1323 /* First retransmit timeout */
1324 if (tc->rto_boff == 1)
1325 tcp_rtx_timeout_cc (tc);
1327 /* Exponential backoff */
1328 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1330 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1332 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1333 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1335 /* TODO be less aggressive about this */
1336 scoreboard_clear (&tc->sack_sb);
1341 if (tc->snd_una == tc->snd_una_max)
1343 ASSERT (tc->rto_boff > 1 && tc->snd_una == tc->snd_congestion);
1344 clib_warning ("retransmit fail: %U", format_tcp_connection, tc, 2);
1345 /* Try again eventually */
1346 tcp_retransmit_timer_set (tc);
1350 bi = vlib_get_buffer_index (vm, b);
1352 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1353 if (tc->rto_boff == 1)
1354 tc->snd_rxt_ts = tcp_time_now ();
1356 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1357 tcp_retransmit_timer_update (tc);
1359 /* Retransmit for SYN */
1360 else if (tc->state == TCP_STATE_SYN_SENT)
1362 /* Half-open connection actually moved to established but we were
1363 * waiting for syn retransmit to pop to call cleanup from the right
1365 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1367 if (tcp_half_open_connection_cleanup (tc))
1369 clib_warning ("could not remove half-open connection");
1375 /* Try without increasing RTO a number of times. If this fails,
1376 * start growing RTO exponentially */
1378 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1379 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1381 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1384 b = vlib_get_buffer (vm, bi);
1385 tcp_init_buffer (vm, b);
1386 tcp_make_syn (tc, b);
1389 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1391 /* This goes straight to ipx_lookup. Retransmit timer set already */
1392 tcp_push_ip_hdr (tm, tc, b);
1393 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
1395 /* Retransmit SYN-ACK */
1396 else if (tc->state == TCP_STATE_SYN_RCVD)
1399 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1402 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1405 b = vlib_get_buffer (vm, bi);
1406 tcp_make_synack (tc, b);
1407 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1409 /* Retransmit timer already updated, just enqueue to output */
1410 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1414 ASSERT (tc->state == TCP_STATE_CLOSED);
1415 clib_warning ("connection closed ...");
1421 tcp_timer_retransmit_handler (u32 index)
1423 tcp_timer_retransmit_handler_i (index, 0);
1427 tcp_timer_retransmit_syn_handler (u32 index)
1429 tcp_timer_retransmit_handler_i (index, 1);
1433 * Got 0 snd_wnd from peer, try to do something about it.
1437 tcp_timer_persist_handler (u32 index)
1439 tcp_main_t *tm = vnet_get_tcp_main ();
1440 vlib_main_t *vm = vlib_get_main ();
1441 u32 thread_index = vlib_get_thread_index ();
1442 tcp_connection_t *tc;
1444 u32 bi, old_snd_nxt, max_snd_bytes, available_bytes, offset;
1448 tc = tcp_connection_get_if_valid (index, thread_index);
1453 /* Make sure timer handle is set to invalid */
1454 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1456 /* Problem already solved or worse */
1457 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1458 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1461 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1462 offset = tc->snd_una_max - tc->snd_una;
1464 /* Reprogram persist if no new bytes available to send. We may have data
1466 if (!available_bytes)
1468 tcp_persist_timer_set (tc);
1472 if (available_bytes <= offset)
1474 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1478 /* Increment RTO backoff */
1480 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1483 * Try to force the first unsent segment (or buffer)
1485 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1487 b = vlib_get_buffer (vm, bi);
1488 data = tcp_init_buffer (vm, b);
1490 tcp_validate_txf_size (tc, offset);
1491 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1492 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1493 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1495 b->current_length = n_bytes;
1496 ASSERT (n_bytes != 0 && (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1
1497 || tcp_timer_is_active (tc,
1498 TCP_TIMER_RETRANSMIT)));
1500 /* Allow updating of snd_una_max but don't update snd_nxt */
1501 old_snd_nxt = tc->snd_nxt;
1502 tcp_push_hdr_i (tc, b, tc->state, 0);
1503 tc->snd_nxt = old_snd_nxt;
1504 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1506 /* Just sent new data, enable retransmit */
1507 tcp_retransmit_timer_update (tc);
1511 * Retransmit first unacked segment
1514 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1516 vlib_main_t *vm = vlib_get_main ();
1518 u32 bi, old_snd_nxt, n_bytes;
1520 old_snd_nxt = tc->snd_nxt;
1521 tc->snd_nxt = tc->snd_una;
1523 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1524 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1527 bi = vlib_get_buffer_index (vm, b);
1528 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1530 tc->snd_nxt = old_snd_nxt;
1534 * Do fast retransmit with SACKs
1537 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1539 vlib_main_t *vm = vlib_get_main ();
1540 u32 n_written = 0, offset, max_bytes;
1541 vlib_buffer_t *b = 0;
1542 sack_scoreboard_hole_t *hole;
1543 sack_scoreboard_t *sb;
1544 u32 bi, old_snd_nxt;
1546 u8 snd_limited = 0, can_rescue = 0;
1548 ASSERT (tcp_in_fastrecovery (tc));
1549 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1551 old_snd_nxt = tc->snd_nxt;
1553 snd_space = tcp_available_snd_space (tc);
1555 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1556 while (hole && snd_space > 0)
1558 hole = scoreboard_next_rxt_hole (sb, hole,
1559 tcp_fastrecovery_sent_1_smss (tc),
1560 &can_rescue, &snd_limited);
1563 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1564 || seq_gt (sb->rescue_rxt,
1565 tc->snd_congestion)))
1568 /* If rescue rxt undefined or less than snd_una then one segment of
1569 * up to SMSS octets that MUST include the highest outstanding
1570 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1571 * RecoveryPoint. HighRxt MUST NOT be updated.
1573 max_bytes = clib_min (tc->snd_mss,
1574 tc->snd_congestion - tc->snd_una);
1575 max_bytes = clib_min (max_bytes, snd_space);
1576 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1577 sb->rescue_rxt = tc->snd_congestion;
1578 tc->snd_nxt = tc->snd_una + offset;
1579 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1582 bi = vlib_get_buffer_index (vm, b);
1583 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1587 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1588 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1591 offset = sb->high_rxt - tc->snd_una;
1592 tc->snd_nxt = sb->high_rxt;
1593 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1595 /* Nothing left to retransmit */
1599 bi = vlib_get_buffer_index (vm, b);
1600 sb->high_rxt += n_written;
1601 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1602 ASSERT (n_written <= snd_space);
1603 snd_space -= n_written;
1606 /* If window allows, send 1 SMSS of new data */
1607 tc->snd_nxt = old_snd_nxt;
1611 * Fast retransmit without SACK info
1614 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1616 vlib_main_t *vm = vlib_get_main ();
1617 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1621 ASSERT (tcp_in_fastrecovery (tc));
1622 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1624 /* Start resending from first un-acked segment */
1625 old_snd_nxt = tc->snd_nxt;
1626 tc->snd_nxt = tc->snd_una;
1627 snd_space = tcp_available_snd_space (tc);
1629 while (snd_space > 0)
1631 offset += n_written;
1632 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1634 /* Nothing left to retransmit */
1638 bi = vlib_get_buffer_index (vm, b);
1639 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1640 snd_space -= n_written;
1643 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1644 tc->snd_nxt = old_snd_nxt;
1648 * Do fast retransmit
1651 tcp_fast_retransmit (tcp_connection_t * tc)
1653 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1654 && scoreboard_first_hole (&tc->sack_sb))
1655 tcp_fast_retransmit_sack (tc);
1657 tcp_fast_retransmit_no_sack (tc);
1661 tcp_session_has_ooo_data (tcp_connection_t * tc)
1663 stream_session_t *s =
1664 stream_session_get (tc->c_s_index, tc->c_thread_index);
1665 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1669 tcp46_output_inline (vlib_main_t * vm,
1670 vlib_node_runtime_t * node,
1671 vlib_frame_t * from_frame, int is_ip4)
1673 u32 n_left_from, next_index, *from, *to_next;
1674 u32 my_thread_index = vm->thread_index;
1676 from = vlib_frame_vector_args (from_frame);
1677 n_left_from = from_frame->n_vectors;
1678 next_index = node->cached_next_index;
1679 tcp_set_time_now (my_thread_index);
1681 while (n_left_from > 0)
1685 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1687 while (n_left_from > 0 && n_left_to_next > 0)
1691 tcp_connection_t *tc0;
1693 tcp_header_t *th0 = 0;
1694 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1701 n_left_to_next -= 1;
1703 b0 = vlib_get_buffer (vm, bi0);
1704 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1706 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1708 error0 = TCP_ERROR_INVALID_CONNECTION;
1709 next0 = TCP_OUTPUT_NEXT_DROP;
1713 th0 = vlib_buffer_get_current (b0);
1714 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1718 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1719 IP_PROTOCOL_TCP, 1);
1720 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1721 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1727 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1728 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1729 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1730 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1731 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1735 /* Filter out DUPACKs if there are no OOO segments left */
1737 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1739 if (!tcp_session_has_ooo_data (tc0))
1741 error0 = TCP_ERROR_FILTERED_DUPACKS;
1742 next0 = TCP_OUTPUT_NEXT_DROP;
1747 /* Stop DELACK timer and fix flags */
1748 tc0->flags &= ~(TCP_CONN_SNDACK);
1749 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1751 /* If not retransmitting
1752 * 1) update snd_una_max (SYN, SYNACK, FIN)
1753 * 2) If we're not tracking an ACK, start tracking */
1754 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1756 tc0->snd_una_max = tc0->snd_nxt;
1757 if (tc0->rtt_ts == 0)
1759 tc0->rtt_ts = tcp_time_now ();
1760 tc0->rtt_seq = tc0->snd_nxt;
1764 /* Set the retransmit timer if not set already and not
1765 * doing a pure ACK */
1766 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1767 && tc0->snd_nxt != tc0->snd_una)
1769 tcp_retransmit_timer_set (tc0);
1774 /* Make sure we haven't lost route to our peer */
1775 if (PREDICT_FALSE (tc0->last_fib_check
1776 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1779 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1781 tc0->last_fib_check = tc0->snd_opts.tsval;
1785 clib_warning ("lost connection to peer");
1786 tcp_connection_reset (tc0);
1791 /* Use pre-computed dpo to set next node */
1792 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1793 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1796 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1797 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
1799 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1801 b0->error = node->errors[error0];
1802 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1804 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1807 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1811 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1813 clib_memcpy (&t0->tcp_connection, tc0,
1814 sizeof (t0->tcp_connection));
1817 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1818 n_left_to_next, bi0, next0);
1821 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1824 return from_frame->n_vectors;
1828 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1829 vlib_frame_t * from_frame)
1831 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1835 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1836 vlib_frame_t * from_frame)
1838 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1842 VLIB_REGISTER_NODE (tcp4_output_node) =
1844 .function = tcp4_output,.name = "tcp4-output",
1845 /* Takes a vector of packets. */
1846 .vector_size = sizeof (u32),
1847 .n_errors = TCP_N_ERROR,
1848 .error_strings = tcp_error_strings,
1849 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1851 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1852 foreach_tcp4_output_next
1855 .format_buffer = format_tcp_header,
1856 .format_trace = format_tcp_tx_trace,
1860 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1863 VLIB_REGISTER_NODE (tcp6_output_node) =
1865 .function = tcp6_output,
1866 .name = "tcp6-output",
1867 /* Takes a vector of packets. */
1868 .vector_size = sizeof (u32),
1869 .n_errors = TCP_N_ERROR,
1870 .error_strings = tcp_error_strings,
1871 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1873 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1874 foreach_tcp6_output_next
1877 .format_buffer = format_tcp_header,
1878 .format_trace = format_tcp_tx_trace,
1882 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1885 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1887 tcp_connection_t *tc;
1889 tc = (tcp_connection_t *) tconn;
1890 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1891 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1893 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1895 tc->rtt_ts = tcp_time_now ();
1896 tc->rtt_seq = tc->snd_nxt;
1901 typedef enum _tcp_reset_next
1903 TCP_RESET_NEXT_DROP,
1904 TCP_RESET_NEXT_IP_LOOKUP,
1908 #define foreach_tcp4_reset_next \
1909 _(DROP, "error-drop") \
1910 _(IP_LOOKUP, "ip4-lookup")
1912 #define foreach_tcp6_reset_next \
1913 _(DROP, "error-drop") \
1914 _(IP_LOOKUP, "ip6-lookup")
1917 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
1918 vlib_frame_t * from_frame, u8 is_ip4)
1920 u32 n_left_from, next_index, *from, *to_next;
1921 u32 my_thread_index = vm->thread_index;
1923 from = vlib_frame_vector_args (from_frame);
1924 n_left_from = from_frame->n_vectors;
1926 next_index = node->cached_next_index;
1928 while (n_left_from > 0)
1932 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1934 while (n_left_from > 0 && n_left_to_next > 0)
1940 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
1947 n_left_to_next -= 1;
1949 b0 = vlib_get_buffer (vm, bi0);
1951 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
1952 my_thread_index, is_ip4))
1954 error0 = TCP_ERROR_LOOKUP_DROPS;
1955 next0 = TCP_RESET_NEXT_DROP;
1959 /* Prepare to send to IP lookup */
1960 vnet_buffer (b0)->sw_if_index[VLIB_TX] = 0;
1961 next0 = TCP_RESET_NEXT_IP_LOOKUP;
1964 b0->error = node->errors[error0];
1965 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1966 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1968 th0 = vlib_buffer_get_current (b0);
1970 th0 = ip4_next_header ((ip4_header_t *) th0);
1972 th0 = ip6_next_header ((ip6_header_t *) th0);
1973 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1974 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1977 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1978 n_left_to_next, bi0, next0);
1980 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1982 return from_frame->n_vectors;
1986 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
1987 vlib_frame_t * from_frame)
1989 return tcp46_send_reset_inline (vm, node, from_frame, 1);
1993 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
1994 vlib_frame_t * from_frame)
1996 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2000 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2001 .function = tcp4_send_reset,
2002 .name = "tcp4-reset",
2003 .vector_size = sizeof (u32),
2004 .n_errors = TCP_N_ERROR,
2005 .error_strings = tcp_error_strings,
2006 .n_next_nodes = TCP_RESET_N_NEXT,
2008 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2009 foreach_tcp4_reset_next
2012 .format_trace = format_tcp_tx_trace,
2016 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2019 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2020 .function = tcp6_send_reset,
2021 .name = "tcp6-reset",
2022 .vector_size = sizeof (u32),
2023 .n_errors = TCP_N_ERROR,
2024 .error_strings = tcp_error_strings,
2025 .n_next_nodes = TCP_RESET_N_NEXT,
2027 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2028 foreach_tcp6_reset_next
2031 .format_trace = format_tcp_tx_trace,
2035 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2038 * fd.io coding-style-patch-verification: ON
2041 * eval: (c-set-style "gnu")