2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #include <vnet/tcp/tcp.h>
17 #include <vnet/lisp-cp/packets.h>
20 vlib_node_registration_t tcp4_output_node;
21 vlib_node_registration_t tcp6_output_node;
23 typedef enum _tcp_output_next
26 TCP_OUTPUT_NEXT_IP_LOOKUP,
30 #define foreach_tcp4_output_next \
31 _ (DROP, "error-drop") \
32 _ (IP_LOOKUP, "ip4-lookup")
34 #define foreach_tcp6_output_next \
35 _ (DROP, "error-drop") \
36 _ (IP_LOOKUP, "ip6-lookup")
38 static char *tcp_error_strings[] = {
39 #define tcp_error(n,s) s,
40 #include <vnet/tcp/tcp_error.def>
46 tcp_header_t tcp_header;
47 tcp_connection_t tcp_connection;
53 format_tcp_tx_trace (u8 * s, va_list * args)
55 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
56 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
57 tcp_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *);
58 u32 indent = format_get_indent (s);
60 s = format (s, "%U\n%U%U",
61 format_tcp_header, &t->tcp_header, 128,
62 format_white_space, indent,
63 format_tcp_connection, &t->tcp_connection, 1);
69 tcp_window_compute_scale (u32 window)
72 while (wnd_scale < TCP_MAX_WND_SCALE && (window >> wnd_scale) > TCP_WND_MAX)
78 * Update max segment size we're able to process.
80 * The value is constrained by our interface's MTU and IP options. It is
81 * also what we advertise to our peer.
84 tcp_update_rcv_mss (tcp_connection_t * tc)
86 /* TODO find our iface MTU */
87 tc->mss = dummy_mtu - sizeof (tcp_header_t);
91 * TCP's initial window
94 tcp_initial_wnd_unscaled (tcp_connection_t * tc)
96 /* RFC 6928 recommends the value lower. However at the time our connections
97 * are initialized, fifos may not be allocated. Therefore, advertise the
98 * smallest possible unscaled window size and update once fifos are
99 * assigned to the session.
102 tcp_update_rcv_mss (tc);
103 TCP_IW_N_SEGMENTS * tc->mss;
105 return TCP_MIN_RX_FIFO_SIZE;
109 * Compute initial window and scale factor. As per RFC1323, window field in
110 * SYN and SYN-ACK segments is never scaled.
113 tcp_initial_window_to_advertise (tcp_connection_t * tc)
117 /* Initial wnd for SYN. Fifos are not allocated yet.
118 * Use some predefined value. For SYN-ACK we still want the
119 * scale to be computed in the same way */
120 max_fifo = TCP_MAX_RX_FIFO_SIZE;
122 tc->rcv_wscale = tcp_window_compute_scale (max_fifo);
123 tc->rcv_wnd = tcp_initial_wnd_unscaled (tc);
125 return clib_min (tc->rcv_wnd, TCP_WND_MAX);
129 * Compute and return window to advertise, scaled as per RFC1323
132 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
134 if (state < TCP_STATE_ESTABLISHED)
135 return tcp_initial_window_to_advertise (tc);
137 tcp_update_rcv_wnd (tc);
139 if (tc->rcv_wnd == 0)
141 tc->flags |= TCP_CONN_SENT_RCV_WND0;
145 tc->flags &= ~TCP_CONN_SENT_RCV_WND0;
148 return tc->rcv_wnd >> tc->rcv_wscale;
152 tcp_update_rcv_wnd (tcp_connection_t * tc)
155 u32 available_space, max_fifo, wnd;
158 * Figure out how much space we have available
160 available_space = stream_session_max_rx_enqueue (&tc->connection);
161 max_fifo = stream_session_rx_fifo_size (&tc->connection);
163 ASSERT (tc->rcv_opts.mss < max_fifo);
164 if (available_space < tc->rcv_opts.mss && available_space < max_fifo >> 3)
168 * Use the above and what we know about what we've previously advertised
169 * to compute the new window
171 observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las);
172 if (observed_wnd < 0)
175 /* Bad. Thou shalt not shrink */
176 if (available_space < observed_wnd)
179 TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
183 wnd = available_space;
186 /* Make sure we have a multiple of rcv_wscale */
187 if (wnd && tc->rcv_wscale)
189 wnd &= ~(1 << tc->rcv_wscale);
191 wnd = 1 << tc->rcv_wscale;
194 tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
198 * Write TCP options to segment.
201 tcp_options_write (u8 * data, tcp_options_t * opts)
204 u32 buf, seq_len = 4;
206 if (tcp_opts_mss (opts))
208 *data++ = TCP_OPTION_MSS;
209 *data++ = TCP_OPTION_LEN_MSS;
210 buf = clib_host_to_net_u16 (opts->mss);
211 clib_memcpy (data, &buf, sizeof (opts->mss));
212 data += sizeof (opts->mss);
213 opts_len += TCP_OPTION_LEN_MSS;
216 if (tcp_opts_wscale (opts))
218 *data++ = TCP_OPTION_WINDOW_SCALE;
219 *data++ = TCP_OPTION_LEN_WINDOW_SCALE;
220 *data++ = opts->wscale;
221 opts_len += TCP_OPTION_LEN_WINDOW_SCALE;
224 if (tcp_opts_sack_permitted (opts))
226 *data++ = TCP_OPTION_SACK_PERMITTED;
227 *data++ = TCP_OPTION_LEN_SACK_PERMITTED;
228 opts_len += TCP_OPTION_LEN_SACK_PERMITTED;
231 if (tcp_opts_tstamp (opts))
233 *data++ = TCP_OPTION_TIMESTAMP;
234 *data++ = TCP_OPTION_LEN_TIMESTAMP;
235 buf = clib_host_to_net_u32 (opts->tsval);
236 clib_memcpy (data, &buf, sizeof (opts->tsval));
237 data += sizeof (opts->tsval);
238 buf = clib_host_to_net_u32 (opts->tsecr);
239 clib_memcpy (data, &buf, sizeof (opts->tsecr));
240 data += sizeof (opts->tsecr);
241 opts_len += TCP_OPTION_LEN_TIMESTAMP;
244 if (tcp_opts_sack (opts))
247 u32 n_sack_blocks = clib_min (vec_len (opts->sacks),
248 TCP_OPTS_MAX_SACK_BLOCKS);
250 if (n_sack_blocks != 0)
252 *data++ = TCP_OPTION_SACK_BLOCK;
253 *data++ = 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
254 for (i = 0; i < n_sack_blocks; i++)
256 buf = clib_host_to_net_u32 (opts->sacks[i].start);
257 clib_memcpy (data, &buf, seq_len);
259 buf = clib_host_to_net_u32 (opts->sacks[i].end);
260 clib_memcpy (data, &buf, seq_len);
263 opts_len += 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK;
267 /* Terminate TCP options */
270 *data++ = TCP_OPTION_EOL;
271 opts_len += TCP_OPTION_LEN_EOL;
274 /* Pad with zeroes to a u32 boundary */
277 *data++ = TCP_OPTION_NOOP;
278 opts_len += TCP_OPTION_LEN_NOOP;
284 tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale)
288 opts->flags |= TCP_OPTS_FLAG_MSS;
289 opts->mss = dummy_mtu; /*XXX discover that */
290 len += TCP_OPTION_LEN_MSS;
292 opts->flags |= TCP_OPTS_FLAG_WSCALE;
293 opts->wscale = wnd_scale;
294 len += TCP_OPTION_LEN_WINDOW_SCALE;
296 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
297 opts->tsval = tcp_time_now ();
299 len += TCP_OPTION_LEN_TIMESTAMP;
303 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
304 len += TCP_OPTION_LEN_SACK_PERMITTED;
307 /* Align to needed boundary */
308 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
313 tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
317 opts->flags |= TCP_OPTS_FLAG_MSS;
319 len += TCP_OPTION_LEN_MSS;
321 if (tcp_opts_wscale (&tc->rcv_opts))
323 opts->flags |= TCP_OPTS_FLAG_WSCALE;
324 opts->wscale = tc->rcv_wscale;
325 len += TCP_OPTION_LEN_WINDOW_SCALE;
328 if (tcp_opts_tstamp (&tc->rcv_opts))
330 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
331 opts->tsval = tcp_time_now ();
332 opts->tsecr = tc->tsval_recent;
333 len += TCP_OPTION_LEN_TIMESTAMP;
336 if (tcp_opts_sack_permitted (&tc->rcv_opts))
338 opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED;
339 len += TCP_OPTION_LEN_SACK_PERMITTED;
342 /* Align to needed boundary */
343 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
348 tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
354 if (tcp_opts_tstamp (&tc->rcv_opts))
356 opts->flags |= TCP_OPTS_FLAG_TSTAMP;
357 opts->tsval = tcp_time_now ();
358 opts->tsecr = tc->tsval_recent;
359 len += TCP_OPTION_LEN_TIMESTAMP;
361 if (tcp_opts_sack_permitted (&tc->rcv_opts))
363 if (vec_len (tc->snd_sacks))
365 opts->flags |= TCP_OPTS_FLAG_SACK;
366 opts->sacks = tc->snd_sacks;
367 opts->n_sack_blocks = clib_min (vec_len (tc->snd_sacks),
368 TCP_OPTS_MAX_SACK_BLOCKS);
369 len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks;
373 /* Align to needed boundary */
374 len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN;
379 tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
384 case TCP_STATE_ESTABLISHED:
385 case TCP_STATE_FIN_WAIT_1:
386 return tcp_make_established_options (tc, opts);
387 case TCP_STATE_SYN_RCVD:
388 return tcp_make_synack_options (tc, opts);
389 case TCP_STATE_SYN_SENT:
390 return tcp_make_syn_options (opts, tc->rcv_wscale);
392 clib_warning ("State not handled! %d", state);
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, u16 * n_bufs,
443 vlib_main_t *vm = vlib_get_main ();
446 ASSERT (wanted > *n_bufs);
447 vec_validate_aligned (tm->tx_buffers[thread_index], wanted - 1,
448 CLIB_CACHE_LINE_BYTES);
449 n_alloc = vlib_buffer_alloc (vm, &tm->tx_buffers[thread_index][*n_bufs],
452 _vec_len (tm->tx_buffers[thread_index]) = *n_bufs;
457 tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx)
459 u32 thread_index = vlib_get_thread_index ();
460 u16 n_bufs = vec_len (tm->tx_buffers[thread_index]);
462 TCP_DBG_BUFFER_ALLOC_MAYBE_FAIL (thread_index);
464 if (PREDICT_FALSE (!n_bufs))
466 if (!tcp_alloc_tx_buffers (tm, thread_index, &n_bufs, VLIB_FRAME_SIZE))
472 *bidx = tm->tx_buffers[thread_index][--n_bufs];
473 _vec_len (tm->tx_buffers[thread_index]) = n_bufs;
478 tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
480 if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
481 vlib_buffer_free_one (vm, b->next_buffer);
482 /* Zero all flags but free list index and trace flag */
483 b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1;
485 b->current_length = 0;
486 b->total_length_not_including_first_buffer = 0;
487 vnet_buffer (b)->tcp.flags = 0;
489 /* Leave enough space for headers */
490 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
494 tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
496 ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
497 b->flags &= VLIB_BUFFER_NON_DEFAULT_FREELIST;
498 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
499 b->total_length_not_including_first_buffer = 0;
501 vnet_buffer (b)->tcp.flags = 0;
502 VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b);
503 /* Leave enough space for headers */
504 return vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
511 tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
514 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
515 u8 tcp_opts_len, tcp_hdr_opts_len;
519 wnd = tcp_window_to_advertise (tc, state);
521 /* Make and write options */
522 tcp_opts_len = tcp_make_established_options (tc, snd_opts);
523 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
525 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
526 tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
528 tcp_options_write ((u8 *) (th + 1), snd_opts);
529 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
533 * Convert buffer to ACK
536 tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
538 vlib_main_t *vm = vlib_get_main ();
540 tcp_reuse_buffer (vm, b);
541 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
542 TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
543 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
544 tc->rcv_las = tc->rcv_nxt;
548 * Convert buffer to FIN-ACK
551 tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b)
553 vlib_main_t *vm = vlib_get_main ();
556 tcp_reuse_buffer (vm, b);
558 flags = TCP_FLAG_FIN | TCP_FLAG_ACK;
559 tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags);
561 /* Reset flags, make sure ack is sent */
562 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
566 * Convert buffer to SYN
569 tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
571 u8 tcp_hdr_opts_len, tcp_opts_len;
574 tcp_options_t snd_opts;
576 initial_wnd = tcp_initial_window_to_advertise (tc);
578 /* Make and write options */
579 memset (&snd_opts, 0, sizeof (snd_opts));
580 tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale);
581 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
583 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
584 tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN,
586 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
587 tcp_options_write ((u8 *) (th + 1), &snd_opts);
591 * Convert buffer to SYN-ACK
594 tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
596 vlib_main_t *vm = vlib_get_main ();
597 tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
598 u8 tcp_opts_len, tcp_hdr_opts_len;
602 memset (snd_opts, 0, sizeof (*snd_opts));
603 tcp_reuse_buffer (vm, b);
605 initial_wnd = tcp_initial_window_to_advertise (tc);
606 tcp_opts_len = tcp_make_synack_options (tc, snd_opts);
607 tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
609 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss,
610 tc->rcv_nxt, tcp_hdr_opts_len,
611 TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd);
612 tcp_options_write ((u8 *) (th + 1), snd_opts);
614 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
615 vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
617 /* Init retransmit timer. Use update instead of set because of
619 tcp_retransmit_timer_force_update (tc);
620 TCP_EVT_DBG (TCP_EVT_SYNACK_SENT, tc);
624 tcp_enqueue_to_ip_lookup_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
625 u8 is_ip4, u32 fib_index, u8 flush)
627 tcp_main_t *tm = vnet_get_tcp_main ();
628 u32 thread_index = vlib_get_thread_index ();
629 u32 *to_next, next_index;
632 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
635 vnet_buffer (b)->sw_if_index[VLIB_TX] = fib_index;
636 vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
638 /* Send to IP lookup */
639 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
640 tcp_trajectory_add_start (b, 1);
642 f = tm->ip_lookup_tx_frames[!is_ip4][thread_index];
645 f = vlib_get_frame_to_node (vm, next_index);
647 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = f;
650 to_next = vlib_frame_vector_args (f);
651 to_next[f->n_vectors] = bi;
653 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
655 vlib_put_frame_to_node (vm, next_index, f);
656 tm->ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
661 tcp_enqueue_to_ip_lookup_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
662 u8 is_ip4, u32 fib_index)
664 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, fib_index, 1);
668 tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
669 u8 is_ip4, u32 fib_index)
671 tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, fib_index, 0);
675 tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
678 tcp_main_t *tm = vnet_get_tcp_main ();
679 u32 thread_index = vlib_get_thread_index ();
680 u32 *to_next, next_index;
683 b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
686 /* Decide where to send the packet */
687 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
688 tcp_trajectory_add_start (b, 2);
690 /* Get frame to v4/6 output node */
691 f = tm->tx_frames[!is_ip4][thread_index];
694 f = vlib_get_frame_to_node (vm, next_index);
696 tm->tx_frames[!is_ip4][thread_index] = f;
698 to_next = vlib_frame_vector_args (f);
699 to_next[f->n_vectors] = bi;
701 if (flush || f->n_vectors == VLIB_FRAME_SIZE)
703 vlib_put_frame_to_node (vm, next_index, f);
704 tm->tx_frames[!is_ip4][thread_index] = 0;
709 tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4)
711 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0);
715 tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
718 tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
722 tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
723 tcp_state_t state, u8 thread_index, u8 is_ip4)
728 ip4_address_t src_ip40, dst_ip40;
729 ip6_address_t src_ip60, dst_ip60;
730 u16 src_port, dst_port;
735 /* Find IP and TCP headers */
736 th0 = tcp_buffer_hdr (b0);
738 /* Save src and dst ip */
741 ih4 = vlib_buffer_get_current (b0);
742 ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40);
743 src_ip40.as_u32 = ih4->src_address.as_u32;
744 dst_ip40.as_u32 = ih4->dst_address.as_u32;
748 ih6 = vlib_buffer_get_current (b0);
749 ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60);
750 clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t));
751 clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t));
754 src_port = th0->src_port;
755 dst_port = th0->dst_port;
757 /* Try to determine what/why we're actually resetting */
758 if (state == TCP_STATE_CLOSED)
763 tmp = clib_net_to_host_u32 (th0->seq_number);
765 /* Got a SYN for no listener. */
766 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
767 ack = clib_host_to_net_u32 (tmp + 1);
772 flags = TCP_FLAG_RST;
773 seq = th0->ack_number;
777 tcp_reuse_buffer (vm, b0);
778 tcp_trajectory_add_start (b0, 4);
779 th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack,
780 sizeof (tcp_header_t), flags, 0);
784 ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
786 th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
791 ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60,
793 th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus);
801 * Send reset without reusing existing buffer
803 * It extracts connection info out of original packet
806 tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
809 u32 bi, sw_if_index, fib_index;
810 tcp_main_t *tm = vnet_get_tcp_main ();
811 vlib_main_t *vm = vlib_get_main ();
812 u8 tcp_hdr_len, flags = 0;
813 tcp_header_t *th, *pkt_th;
815 ip4_header_t *ih4, *pkt_ih4;
816 ip6_header_t *ih6, *pkt_ih6;
817 fib_protocol_t fib_proto;
819 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
822 b = vlib_get_buffer (vm, bi);
823 sw_if_index = vnet_buffer (pkt)->sw_if_index[VLIB_RX];
824 fib_proto = is_ip4 ? FIB_PROTOCOL_IP4 : FIB_PROTOCOL_IP6;
825 fib_index = fib_table_get_index_for_sw_if_index (fib_proto, sw_if_index);
826 tcp_init_buffer (vm, b);
828 /* Make and write options */
829 tcp_hdr_len = sizeof (tcp_header_t);
833 pkt_ih4 = vlib_buffer_get_current (pkt);
834 pkt_th = ip4_next_header (pkt_ih4);
838 pkt_ih6 = vlib_buffer_get_current (pkt);
839 pkt_th = ip6_next_header (pkt_ih6);
842 if (tcp_ack (pkt_th))
844 flags = TCP_FLAG_RST;
845 seq = pkt_th->ack_number;
846 ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
850 flags = TCP_FLAG_RST | TCP_FLAG_ACK;
852 ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end);
855 th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port,
856 seq, ack, tcp_hdr_len, flags, 0);
858 /* Swap src and dst ip */
861 ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
862 ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
863 &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
864 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
869 ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
871 ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
872 &pkt_ih6->src_address, IP_PROTOCOL_TCP);
873 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
877 tcp_enqueue_to_ip_lookup_now (vm, b, bi, is_ip4, fib_index);
878 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
882 * Build and set reset packet for connection
885 tcp_send_reset (tcp_connection_t * tc)
887 vlib_main_t *vm = vlib_get_main ();
888 tcp_main_t *tm = vnet_get_tcp_main ();
892 u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len;
895 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
897 b = vlib_get_buffer (vm, bi);
898 tcp_init_buffer (vm, b);
900 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
901 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
902 advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
903 flags = TCP_FLAG_RST;
904 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
905 tc->rcv_nxt, tcp_hdr_opts_len, flags,
907 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
908 ASSERT (opts_write_len == tc->snd_opts_len);
909 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
913 ih4 = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip.ip4,
914 &tc->c_rmt_ip.ip4, IP_PROTOCOL_TCP, 0);
915 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
921 ih6 = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip.ip6,
922 &tc->c_rmt_ip.ip6, IP_PROTOCOL_TCP);
923 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
926 tcp_enqueue_to_ip_lookup_now (vm, b, bi, tc->c_is_ip4, tc->c_fib_index);
927 TCP_EVT_DBG (TCP_EVT_RST_SENT, tc);
931 tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
933 tcp_header_t *th = vlib_buffer_get_current (b);
934 vlib_main_t *vm = vlib_get_main ();
938 ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
939 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
940 th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
947 ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
948 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
949 th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
957 * Builds a SYN packet for a half-open connection and sends it to ipx_lookup.
958 * The packet is not forwarded through tcpx_output to avoid doing lookups
959 * in the half_open pool.
962 tcp_send_syn (tcp_connection_t * tc)
966 tcp_main_t *tm = vnet_get_tcp_main ();
967 vlib_main_t *vm = vlib_get_main ();
970 * Setup retransmit and establish timers before requesting buffer
971 * such that we can return if we've ran out.
973 tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
974 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
975 tc->rto * TCP_TO_TIMER_TICK);
977 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
980 b = vlib_get_buffer (vm, bi);
981 tcp_init_buffer (vm, b);
982 tcp_make_syn (tc, b);
984 /* Measure RTT with this */
985 tc->rtt_ts = tcp_time_now ();
986 tc->rtt_seq = tc->snd_nxt;
989 tcp_push_ip_hdr (tm, tc, b);
990 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4, tc->c_fib_index);
991 TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
995 * Flush tx frame populated by retransmits and timer pops
998 tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1000 if (tcp_main.tx_frames[!is_ip4][thread_index])
1003 next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index;
1004 vlib_put_frame_to_node (vm, next_index,
1005 tcp_main.tx_frames[!is_ip4][thread_index]);
1006 tcp_main.tx_frames[!is_ip4][thread_index] = 0;
1011 * Flush ip lookup tx frames populated by timer pops
1014 tcp_flush_frame_to_ip_lookup (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
1016 if (tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index])
1019 next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
1020 vlib_put_frame_to_node (vm, next_index,
1021 tcp_main.ip_lookup_tx_frames[!is_ip4]
1023 tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
1028 * Flush v4 and v6 tcp and ip-lookup tx frames for thread index
1031 tcp_flush_frames_to_output (u8 thread_index)
1033 vlib_main_t *vm = vlib_get_main ();
1034 tcp_flush_frame_to_output (vm, thread_index, 1);
1035 tcp_flush_frame_to_output (vm, thread_index, 0);
1036 tcp_flush_frame_to_ip_lookup (vm, thread_index, 1);
1037 tcp_flush_frame_to_ip_lookup (vm, thread_index, 0);
1044 tcp_send_fin (tcp_connection_t * tc)
1046 tcp_main_t *tm = vnet_get_tcp_main ();
1047 vlib_main_t *vm = vlib_get_main ();
1052 tcp_retransmit_timer_force_update (tc);
1053 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1055 b = vlib_get_buffer (vm, bi);
1056 tcp_init_buffer (vm, b);
1057 fin_snt = tc->flags & TCP_CONN_FINSNT;
1059 tc->snd_nxt = tc->snd_una;
1060 tcp_make_fin (tc, b);
1061 tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4);
1064 tc->flags |= TCP_CONN_FINSNT;
1065 tc->flags &= ~TCP_CONN_FINPNDG;
1066 /* Account for the FIN */
1067 tc->snd_una_max += 1;
1068 tc->snd_nxt = tc->snd_una_max;
1072 tc->snd_nxt = tc->snd_una_max;
1074 TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
1078 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state)
1082 case TCP_STATE_ESTABLISHED:
1083 return TCP_FLAG_ACK;
1084 case TCP_STATE_SYN_RCVD:
1085 return TCP_FLAG_SYN | TCP_FLAG_ACK;
1086 case TCP_STATE_SYN_SENT:
1087 return TCP_FLAG_SYN;
1088 case TCP_STATE_LAST_ACK:
1089 case TCP_STATE_FIN_WAIT_1:
1090 if (tc->snd_nxt + 1 < tc->snd_una_max)
1091 return TCP_FLAG_ACK;
1093 return TCP_FLAG_FIN;
1095 clib_warning ("Shouldn't be here!");
1101 * Push TCP header and update connection variables
1104 tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
1105 tcp_state_t next_state, u8 compute_opts)
1107 u32 advertise_wnd, data_len;
1108 u8 tcp_hdr_opts_len, opts_write_len, flags;
1111 data_len = b->current_length + b->total_length_not_including_first_buffer;
1112 ASSERT (!b->total_length_not_including_first_buffer
1113 || (b->flags & VLIB_BUFFER_NEXT_PRESENT));
1114 vnet_buffer (b)->tcp.flags = 0;
1117 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1119 tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
1120 advertise_wnd = tcp_window_to_advertise (tc, next_state);
1121 flags = tcp_make_state_flags (tc, next_state);
1123 /* Push header and options */
1124 th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
1125 tc->rcv_nxt, tcp_hdr_opts_len, flags,
1127 opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
1129 ASSERT (opts_write_len == tc->snd_opts_len);
1130 vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
1133 * Update connection variables
1136 tc->snd_nxt += data_len;
1137 tc->rcv_las = tc->rcv_nxt;
1139 /* TODO this is updated in output as well ... */
1140 if (seq_gt (tc->snd_nxt, tc->snd_una_max))
1142 tc->snd_una_max = tc->snd_nxt;
1143 tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
1146 TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
1150 tcp_send_ack (tcp_connection_t * tc)
1152 tcp_main_t *tm = vnet_get_tcp_main ();
1153 vlib_main_t *vm = vlib_get_main ();
1159 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1161 b = vlib_get_buffer (vm, bi);
1162 tcp_init_buffer (vm, b);
1164 /* Fill in the ACK */
1165 tcp_make_ack (tc, b);
1166 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1170 * Delayed ack timer handler
1172 * Sends delayed ACK when timer expires
1175 tcp_timer_delack_handler (u32 index)
1177 u32 thread_index = vlib_get_thread_index ();
1178 tcp_connection_t *tc;
1180 tc = tcp_connection_get (index, thread_index);
1181 tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
1186 * Build a retransmit segment
1188 * @return the number of bytes in the segment or 0 if there's nothing to
1192 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
1193 u32 max_deq_bytes, vlib_buffer_t ** b)
1195 tcp_main_t *tm = vnet_get_tcp_main ();
1196 vlib_main_t *vm = vlib_get_main ();
1198 u32 start, bi, available_bytes, seg_size;
1201 ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
1202 ASSERT (max_deq_bytes != 0);
1205 * Make sure we can retransmit something
1207 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1208 ASSERT (available_bytes >= offset);
1209 available_bytes -= offset;
1210 if (!available_bytes)
1212 max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
1213 max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
1215 /* Start is beyond snd_congestion */
1216 start = tc->snd_una + offset;
1217 if (seq_geq (start, tc->snd_congestion))
1220 /* Don't overshoot snd_congestion */
1221 if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
1223 max_deq_bytes = tc->snd_congestion - start;
1224 if (max_deq_bytes == 0)
1228 seg_size = max_deq_bytes + MAX_HDRS_LEN;
1233 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1236 * Allocate and fill in buffer(s)
1239 /* Easy case, buffer size greater than mss */
1240 if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
1242 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1244 *b = vlib_get_buffer (vm, bi);
1245 data = tcp_init_buffer (vm, *b);
1246 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1248 ASSERT (n_bytes == max_deq_bytes);
1249 b[0]->current_length = n_bytes;
1250 tcp_push_hdr_i (tc, *b, tc->state, 0);
1252 /* Split mss into multiple buffers */
1255 u32 chain_bi = ~0, n_bufs_per_seg;
1256 u32 thread_index = vlib_get_thread_index ();
1257 u16 n_peeked, len_to_deq, available_bufs;
1258 vlib_buffer_t *chain_b, *prev_b;
1261 /* Make sure we have enough buffers */
1262 n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer);
1263 available_bufs = vec_len (tm->tx_buffers[thread_index]);
1264 if (n_bufs_per_seg > available_bufs)
1266 tcp_alloc_tx_buffers (tm, thread_index, &available_bufs,
1269 if (n_bufs_per_seg > available_bufs)
1276 tcp_get_free_buffer_index (tm, &bi);
1277 ASSERT (bi != (u32) ~ 0);
1278 *b = vlib_get_buffer (vm, bi);
1279 data = tcp_init_buffer (vm, *b);
1280 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1281 tm->bytes_per_buffer -
1283 b[0]->current_length = n_bytes;
1284 b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
1285 b[0]->total_length_not_including_first_buffer = 0;
1286 max_deq_bytes -= n_bytes;
1289 for (i = 1; i < n_bufs_per_seg; i++)
1292 len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer);
1293 tcp_get_free_buffer_index (tm, &chain_bi);
1294 ASSERT (chain_bi != (u32) ~ 0);
1295 chain_b = vlib_get_buffer (vm, chain_bi);
1296 chain_b->current_data = 0;
1297 data = vlib_buffer_get_current (chain_b);
1298 n_peeked = stream_session_peek_bytes (&tc->connection, data,
1299 offset + n_bytes, len_to_deq);
1300 ASSERT (n_peeked == len_to_deq);
1301 n_bytes += n_peeked;
1302 chain_b->current_length = n_peeked;
1303 chain_b->next_buffer = 0;
1305 /* update previous buffer */
1306 prev_b->next_buffer = chain_bi;
1307 prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
1309 max_deq_bytes -= n_peeked;
1310 b[0]->total_length_not_including_first_buffer += n_peeked;
1313 tcp_push_hdr_i (tc, *b, tc->state, 0);
1316 ASSERT (n_bytes > 0);
1317 ASSERT (((*b)->current_data + (*b)->current_length) <=
1318 tm->bytes_per_buffer);
1320 if (tcp_in_fastrecovery (tc))
1321 tc->snd_rxt_bytes += n_bytes;
1324 TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes);
1329 * Reset congestion control, switch cwnd to loss window and try again.
1332 tcp_rtx_timeout_cc (tcp_connection_t * tc)
1334 tc->prev_ssthresh = tc->ssthresh;
1335 tc->prev_cwnd = tc->cwnd;
1337 /* Cleanly recover cc (also clears up fast retransmit) */
1338 if (tcp_in_fastrecovery (tc))
1339 tcp_cc_fastrecovery_exit (tc);
1341 /* Start again from the beginning */
1342 tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
1343 tc->cwnd = tcp_loss_wnd (tc);
1344 tc->snd_congestion = tc->snd_una_max;
1346 tcp_recovery_on (tc);
1350 tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
1352 tcp_main_t *tm = vnet_get_tcp_main ();
1353 vlib_main_t *vm = vlib_get_main ();
1354 u32 thread_index = vlib_get_thread_index ();
1355 tcp_connection_t *tc;
1356 vlib_buffer_t *b = 0;
1361 tc = tcp_half_open_connection_get (index);
1362 /* Note: the connection may have transitioned to ESTABLISHED... */
1363 if (PREDICT_FALSE (tc == 0))
1365 tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
1369 tc = tcp_connection_get (index, thread_index);
1370 /* Note: the connection may have been closed and pool_put */
1371 if (PREDICT_FALSE (tc == 0))
1373 tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID;
1376 if (tc->state >= TCP_STATE_ESTABLISHED)
1378 /* Lost FIN, retransmit and return */
1379 if (tcp_is_lost_fin (tc))
1383 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1387 /* Shouldn't be here */
1388 if (tc->snd_una == tc->snd_una_max)
1390 tcp_recovery_off (tc);
1394 /* We're not in recovery so make sure rto_boff is 0 */
1395 if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
1398 tcp_update_rto (tc);
1401 /* Increment RTO backoff (also equal to number of retries) and go back
1402 * to first un-acked byte */
1405 /* First retransmit timeout */
1406 if (tc->rto_boff == 1)
1407 tcp_rtx_timeout_cc (tc);
1409 tc->snd_nxt = tc->snd_una;
1410 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1412 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
1414 /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */
1415 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1417 /* TODO be less aggressive about this */
1418 scoreboard_clear (&tc->sack_sb);
1422 tcp_retransmit_timer_set (tc);
1426 bi = vlib_get_buffer_index (vm, b);
1428 /* For first retransmit, record timestamp (Eifel detection RFC3522) */
1429 if (tc->rto_boff == 1)
1430 tc->snd_rxt_ts = tcp_time_now ();
1432 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1433 tcp_retransmit_timer_update (tc);
1435 /* Retransmit for SYN */
1436 else if (tc->state == TCP_STATE_SYN_SENT)
1438 /* Half-open connection actually moved to established but we were
1439 * waiting for syn retransmit to pop to call cleanup from the right
1441 if (tc->flags & TCP_CONN_HALF_OPEN_DONE)
1443 if (tcp_half_open_connection_cleanup (tc))
1445 clib_warning ("could not remove half-open connection");
1451 /* Try without increasing RTO a number of times. If this fails,
1452 * start growing RTO exponentially */
1454 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1455 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1457 tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
1458 tc->rto * TCP_TO_TIMER_TICK);
1460 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1463 b = vlib_get_buffer (vm, bi);
1464 tcp_init_buffer (vm, b);
1465 tcp_make_syn (tc, b);
1468 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0);
1470 /* This goes straight to ipx_lookup. Retransmit timer set already */
1471 tcp_push_ip_hdr (tm, tc, b);
1472 tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4, tc->c_fib_index);
1474 /* Retransmit SYN-ACK */
1475 else if (tc->state == TCP_STATE_SYN_RCVD)
1478 if (tc->rto_boff > TCP_RTO_SYN_RETRIES)
1479 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1482 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1484 tcp_retransmit_timer_force_update (tc);
1488 b = vlib_get_buffer (vm, bi);
1489 tcp_init_buffer (vm, b);
1490 tcp_make_synack (tc, b);
1491 TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1);
1493 /* Retransmit timer already updated, just enqueue to output */
1494 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1498 ASSERT (tc->state == TCP_STATE_CLOSED);
1504 tcp_timer_retransmit_handler (u32 index)
1506 tcp_timer_retransmit_handler_i (index, 0);
1510 tcp_timer_retransmit_syn_handler (u32 index)
1512 tcp_timer_retransmit_handler_i (index, 1);
1516 * Got 0 snd_wnd from peer, try to do something about it.
1520 tcp_timer_persist_handler (u32 index)
1522 tcp_main_t *tm = vnet_get_tcp_main ();
1523 vlib_main_t *vm = vlib_get_main ();
1524 u32 thread_index = vlib_get_thread_index ();
1525 tcp_connection_t *tc;
1527 u32 bi, max_snd_bytes, available_bytes, offset;
1531 tc = tcp_connection_get_if_valid (index, thread_index);
1536 /* Make sure timer handle is set to invalid */
1537 tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
1539 /* Problem already solved or worse */
1540 if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED
1541 || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
1544 available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection);
1545 offset = tc->snd_una_max - tc->snd_una;
1547 /* Reprogram persist if no new bytes available to send. We may have data
1549 if (!available_bytes)
1551 tcp_persist_timer_set (tc);
1555 if (available_bytes <= offset)
1557 ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT));
1561 /* Increment RTO backoff */
1563 tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
1566 * Try to force the first unsent segment (or buffer)
1568 if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
1570 b = vlib_get_buffer (vm, bi);
1571 data = tcp_init_buffer (vm, b);
1573 tcp_validate_txf_size (tc, offset);
1574 tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
1575 max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN);
1576 n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
1578 b->current_length = n_bytes;
1579 ASSERT (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)
1580 || tc->snd_nxt == tc->snd_una_max
1581 || tc->rto_boff > 1));
1583 tcp_push_hdr_i (tc, b, tc->state, 0);
1584 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1586 /* Just sent new data, enable retransmit */
1587 tcp_retransmit_timer_update (tc);
1591 * Retransmit first unacked segment
1594 tcp_retransmit_first_unacked (tcp_connection_t * tc)
1596 vlib_main_t *vm = vlib_get_main ();
1598 u32 bi, old_snd_nxt, n_bytes;
1600 old_snd_nxt = tc->snd_nxt;
1601 tc->snd_nxt = tc->snd_una;
1603 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2);
1604 n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b);
1607 bi = vlib_get_buffer_index (vm, b);
1608 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1610 tc->snd_nxt = old_snd_nxt;
1614 * Do fast retransmit with SACKs
1617 tcp_fast_retransmit_sack (tcp_connection_t * tc)
1619 vlib_main_t *vm = vlib_get_main ();
1620 u32 n_written = 0, offset, max_bytes;
1621 vlib_buffer_t *b = 0;
1622 sack_scoreboard_hole_t *hole;
1623 sack_scoreboard_t *sb;
1624 u32 bi, old_snd_nxt;
1626 u8 snd_limited = 0, can_rescue = 0;
1628 ASSERT (tcp_in_fastrecovery (tc));
1629 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1631 old_snd_nxt = tc->snd_nxt;
1633 snd_space = tcp_available_snd_space (tc);
1635 hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
1636 while (hole && snd_space > 0)
1638 hole = scoreboard_next_rxt_hole (sb, hole,
1639 tcp_fastrecovery_sent_1_smss (tc),
1640 &can_rescue, &snd_limited);
1643 if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
1644 || seq_gt (sb->rescue_rxt,
1645 tc->snd_congestion)))
1648 /* If rescue rxt undefined or less than snd_una then one segment of
1649 * up to SMSS octets that MUST include the highest outstanding
1650 * unSACKed sequence number SHOULD be returned, and RescueRxt set to
1651 * RecoveryPoint. HighRxt MUST NOT be updated.
1653 max_bytes = clib_min (tc->snd_mss,
1654 tc->snd_congestion - tc->snd_una);
1655 max_bytes = clib_min (max_bytes, snd_space);
1656 offset = tc->snd_congestion - tc->snd_una - max_bytes;
1657 sb->rescue_rxt = tc->snd_congestion;
1658 tc->snd_nxt = tc->snd_una + offset;
1659 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes,
1664 bi = vlib_get_buffer_index (vm, b);
1665 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1669 max_bytes = clib_min (hole->end - sb->high_rxt, snd_space);
1670 max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
1673 offset = sb->high_rxt - tc->snd_una;
1674 tc->snd_nxt = sb->high_rxt;
1675 n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b);
1677 /* Nothing left to retransmit */
1681 bi = vlib_get_buffer_index (vm, b);
1682 sb->high_rxt += n_written;
1683 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1684 ASSERT (n_written <= snd_space);
1685 snd_space -= n_written;
1689 /* If window allows, send 1 SMSS of new data */
1690 tc->snd_nxt = old_snd_nxt;
1694 * Fast retransmit without SACK info
1697 tcp_fast_retransmit_no_sack (tcp_connection_t * tc)
1699 vlib_main_t *vm = vlib_get_main ();
1700 u32 n_written = 0, offset = 0, bi, old_snd_nxt;
1704 ASSERT (tcp_in_fastrecovery (tc));
1705 TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
1707 /* Start resending from first un-acked segment */
1708 old_snd_nxt = tc->snd_nxt;
1709 tc->snd_nxt = tc->snd_una;
1710 snd_space = tcp_available_snd_space (tc);
1712 while (snd_space > 0)
1714 offset += n_written;
1715 n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b);
1717 /* Nothing left to retransmit */
1721 bi = vlib_get_buffer_index (vm, b);
1722 tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
1723 snd_space -= n_written;
1726 /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
1727 tc->snd_nxt = old_snd_nxt;
1731 * Do fast retransmit
1734 tcp_fast_retransmit (tcp_connection_t * tc)
1736 if (tcp_opts_sack_permitted (&tc->rcv_opts)
1737 && scoreboard_first_hole (&tc->sack_sb))
1738 tcp_fast_retransmit_sack (tc);
1740 tcp_fast_retransmit_no_sack (tc);
1744 tcp_session_has_ooo_data (tcp_connection_t * tc)
1746 stream_session_t *s = session_get (tc->c_s_index, tc->c_thread_index);
1747 return svm_fifo_has_ooo_data (s->server_rx_fifo);
1751 tcp46_output_inline (vlib_main_t * vm,
1752 vlib_node_runtime_t * node,
1753 vlib_frame_t * from_frame, int is_ip4)
1755 u32 n_left_from, next_index, *from, *to_next;
1756 u32 my_thread_index = vm->thread_index;
1758 from = vlib_frame_vector_args (from_frame);
1759 n_left_from = from_frame->n_vectors;
1760 next_index = node->cached_next_index;
1761 tcp_set_time_now (my_thread_index);
1763 while (n_left_from > 0)
1767 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1769 while (n_left_from > 0 && n_left_to_next > 0)
1773 tcp_connection_t *tc0;
1775 tcp_header_t *th0 = 0;
1776 u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP;
1778 if (n_left_from > 1)
1781 pb = vlib_get_buffer (vm, from[1]);
1782 vlib_prefetch_buffer_header (pb, STORE);
1783 CLIB_PREFETCH (pb->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
1791 n_left_to_next -= 1;
1793 b0 = vlib_get_buffer (vm, bi0);
1794 tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
1796 if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED))
1798 error0 = TCP_ERROR_INVALID_CONNECTION;
1799 next0 = TCP_OUTPUT_NEXT_DROP;
1803 th0 = vlib_buffer_get_current (b0);
1804 TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
1808 vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
1809 IP_PROTOCOL_TCP, 1);
1810 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1811 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1817 ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
1818 &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
1819 b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
1820 vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
1821 vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
1825 /* Filter out DUPACKs if there are no OOO segments left */
1827 (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
1829 /* N.B. Should not filter burst of dupacks. Two issues:
1830 * 1) dupacks open cwnd on remote peer when congested
1831 * 2) acks leaving should have the latest rcv_wnd since the
1832 * burst may have eaten up all of it, so only the old ones
1833 * could be filtered.
1835 if (!tcp_session_has_ooo_data (tc0))
1837 error0 = TCP_ERROR_FILTERED_DUPACKS;
1838 next0 = TCP_OUTPUT_NEXT_DROP;
1843 /* Stop DELACK timer and fix flags */
1844 tc0->flags &= ~(TCP_CONN_SNDACK);
1845 tcp_timer_reset (tc0, TCP_TIMER_DELACK);
1847 /* If not retransmitting
1848 * 1) update snd_una_max (SYN, SYNACK, FIN)
1849 * 2) If we're not tracking an ACK, start tracking */
1850 if (seq_lt (tc0->snd_una_max, tc0->snd_nxt))
1852 tc0->snd_una_max = tc0->snd_nxt;
1853 if (tc0->rtt_ts == 0)
1855 tc0->rtt_ts = tcp_time_now ();
1856 tc0->rtt_seq = tc0->snd_nxt;
1860 /* Set the retransmit timer if not set already and not
1861 * doing a pure ACK */
1862 if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT)
1863 && tc0->snd_nxt != tc0->snd_una)
1865 tcp_retransmit_timer_set (tc0);
1870 /* Make sure we haven't lost route to our peer */
1871 if (PREDICT_FALSE (tc0->last_fib_check
1872 < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD))
1875 (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0)))
1877 tc0->last_fib_check = tc0->snd_opts.tsval;
1881 clib_warning ("lost connection to peer");
1882 tcp_connection_reset (tc0);
1887 /* Use pre-computed dpo to set next node */
1888 next0 = tc0->c_rmt_dpo.dpoi_next_node;
1889 vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index;
1892 vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
1893 vnet_buffer (b0)->sw_if_index[VLIB_TX] = tc0->c_fib_index;
1895 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
1897 b0->error = node->errors[error0];
1898 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1900 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
1903 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
1907 memset (&t0->tcp_header, 0, sizeof (t0->tcp_header));
1909 clib_memcpy (&t0->tcp_connection, tc0,
1910 sizeof (t0->tcp_connection));
1913 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1914 n_left_to_next, bi0, next0);
1917 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1920 return from_frame->n_vectors;
1924 tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1925 vlib_frame_t * from_frame)
1927 return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
1931 tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node,
1932 vlib_frame_t * from_frame)
1934 return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
1938 VLIB_REGISTER_NODE (tcp4_output_node) =
1940 .function = tcp4_output,.name = "tcp4-output",
1941 /* Takes a vector of packets. */
1942 .vector_size = sizeof (u32),
1943 .n_errors = TCP_N_ERROR,
1944 .error_strings = tcp_error_strings,
1945 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1947 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1948 foreach_tcp4_output_next
1951 .format_buffer = format_tcp_header,
1952 .format_trace = format_tcp_tx_trace,
1956 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output);
1959 VLIB_REGISTER_NODE (tcp6_output_node) =
1961 .function = tcp6_output,
1962 .name = "tcp6-output",
1963 /* Takes a vector of packets. */
1964 .vector_size = sizeof (u32),
1965 .n_errors = TCP_N_ERROR,
1966 .error_strings = tcp_error_strings,
1967 .n_next_nodes = TCP_OUTPUT_N_NEXT,
1969 #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n,
1970 foreach_tcp6_output_next
1973 .format_buffer = format_tcp_header,
1974 .format_trace = format_tcp_tx_trace,
1978 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output);
1981 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
1983 tcp_connection_t *tc;
1985 tc = (tcp_connection_t *) tconn;
1986 tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
1987 ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
1989 if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc))
1991 tc->rtt_ts = tcp_time_now ();
1992 tc->rtt_seq = tc->snd_nxt;
1994 tcp_trajectory_add_start (b, 3);
1998 typedef enum _tcp_reset_next
2000 TCP_RESET_NEXT_DROP,
2001 TCP_RESET_NEXT_IP_LOOKUP,
2005 #define foreach_tcp4_reset_next \
2006 _(DROP, "error-drop") \
2007 _(IP_LOOKUP, "ip4-lookup")
2009 #define foreach_tcp6_reset_next \
2010 _(DROP, "error-drop") \
2011 _(IP_LOOKUP, "ip6-lookup")
2014 tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
2015 vlib_frame_t * from_frame, u8 is_ip4)
2017 u32 n_left_from, next_index, *from, *to_next;
2018 u32 my_thread_index = vm->thread_index;
2020 from = vlib_frame_vector_args (from_frame);
2021 n_left_from = from_frame->n_vectors;
2023 next_index = node->cached_next_index;
2025 while (n_left_from > 0)
2029 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
2031 while (n_left_from > 0 && n_left_to_next > 0)
2037 u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP;
2044 n_left_to_next -= 1;
2046 b0 = vlib_get_buffer (vm, bi0);
2048 if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags,
2049 my_thread_index, is_ip4))
2051 error0 = TCP_ERROR_LOOKUP_DROPS;
2052 next0 = TCP_RESET_NEXT_DROP;
2056 /* Prepare to send to IP lookup */
2057 vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
2058 next0 = TCP_RESET_NEXT_IP_LOOKUP;
2061 b0->error = node->errors[error0];
2062 b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
2063 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
2065 th0 = vlib_buffer_get_current (b0);
2067 th0 = ip4_next_header ((ip4_header_t *) th0);
2069 th0 = ip6_next_header ((ip6_header_t *) th0);
2070 t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
2071 clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header));
2074 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
2075 n_left_to_next, bi0, next0);
2077 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
2079 return from_frame->n_vectors;
2083 tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2084 vlib_frame_t * from_frame)
2086 return tcp46_send_reset_inline (vm, node, from_frame, 1);
2090 tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node,
2091 vlib_frame_t * from_frame)
2093 return tcp46_send_reset_inline (vm, node, from_frame, 0);
2097 VLIB_REGISTER_NODE (tcp4_reset_node) = {
2098 .function = tcp4_send_reset,
2099 .name = "tcp4-reset",
2100 .vector_size = sizeof (u32),
2101 .n_errors = TCP_N_ERROR,
2102 .error_strings = tcp_error_strings,
2103 .n_next_nodes = TCP_RESET_N_NEXT,
2105 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2106 foreach_tcp4_reset_next
2109 .format_trace = format_tcp_tx_trace,
2113 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset);
2116 VLIB_REGISTER_NODE (tcp6_reset_node) = {
2117 .function = tcp6_send_reset,
2118 .name = "tcp6-reset",
2119 .vector_size = sizeof (u32),
2120 .n_errors = TCP_N_ERROR,
2121 .error_strings = tcp_error_strings,
2122 .n_next_nodes = TCP_RESET_N_NEXT,
2124 #define _(s,n) [TCP_RESET_NEXT_##s] = n,
2125 foreach_tcp6_reset_next
2128 .format_trace = format_tcp_tx_trace,
2132 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset);
2135 * fd.io coding-style-patch-verification: ON
2138 * eval: (c-set-style "gnu")