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.
19 #include <vnet/vnet.h>
20 #include <vnet/ip/ip.h>
21 #include <vnet/tcp/tcp_packet.h>
22 #include <vnet/tcp/tcp_timer.h>
23 #include <vnet/session/transport.h>
24 #include <vnet/session/session.h>
26 #define TCP_TICK 10e-3 /**< TCP tick period (s) */
27 #define THZ 1/TCP_TICK /**< TCP tick frequency */
28 #define TCP_TSTAMP_RESOLUTION TCP_TICK /**< Time stamp resolution */
29 #define TCP_PAWS_IDLE 24 * 24 * 60 * 60 * THZ /**< 24 days */
30 #define TCP_MAX_OPTION_SPACE 40
32 #define TCP_DUPACK_THRESHOLD 3
33 #define TCP_MAX_RX_FIFO_SIZE 2 << 20
34 #define TCP_IW_N_SEGMENTS 10
36 /** TCP FSM state definitions as per RFC793. */
37 #define foreach_tcp_fsm_state \
40 _(SYN_SENT, "SYN_SENT") \
41 _(SYN_RCVD, "SYN_RCVD") \
42 _(ESTABLISHED, "ESTABLISHED") \
43 _(CLOSE_WAIT, "CLOSE_WAIT") \
44 _(FIN_WAIT_1, "FIN_WAIT_1") \
45 _(LAST_ACK, "LAST_ACK") \
46 _(CLOSING, "CLOSING") \
47 _(FIN_WAIT_2, "FIN_WAIT_2") \
48 _(TIME_WAIT, "TIME_WAIT")
50 typedef enum _tcp_state
52 #define _(sym, str) TCP_STATE_##sym,
58 format_function_t format_tcp_state;
61 #define foreach_tcp_timer \
62 _(RETRANSMIT, "RETRANSMIT") \
63 _(DELACK, "DELAYED ACK") \
64 _(PERSIST, "PERSIST") \
67 _(RETRANSMIT_SYN, "RETRANSMIT_SYN") \
68 _(ESTABLISH, "ESTABLISH")
70 typedef enum _tcp_timers
72 #define _(sym, str) TCP_TIMER_##sym,
78 typedef void (timer_expiration_handler) (u32 index);
80 extern timer_expiration_handler tcp_timer_delack_handler;
81 extern timer_expiration_handler tcp_timer_retransmit_handler;
82 extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
84 #define TCP_TIMER_HANDLE_INVALID ((u32) ~0)
86 /* Timer delays as multiples of 100ms */
87 #define TCP_TO_TIMER_TICK TCP_TICK*10 /* Period for converting from TCP
88 * ticks to timer units */
89 #define TCP_DELACK_TIME 1 /* 0.1s */
90 #define TCP_ESTABLISH_TIME 750 /* 75s */
91 #define TCP_2MSL_TIME 300 /* 30s */
93 #define TCP_RTO_MAX 60 * THZ /* Min max RTO (60s) as per RFC6298 */
94 #define TCP_RTT_MAX 30 * THZ /* 30s (probably too much) */
95 #define TCP_RTO_SYN_RETRIES 3 /* SYN retries without doubling RTO */
96 #define TCP_RTO_INIT 1 * THZ /* Initial retransmit timer */
98 void tcp_update_time (f64 now, u32 thread_index);
100 /** TCP connection flags */
101 #define foreach_tcp_connection_flag \
102 _(DELACK, "Delay ACK") \
103 _(SNDACK, "Send ACK") \
104 _(BURSTACK, "Burst ACK set") \
105 _(SENT_RCV_WND0, "Sent 0 receive window") \
106 _(RECOVERY, "Recovery on") \
107 _(FAST_RECOVERY, "Fast Recovery on")
109 typedef enum _tcp_connection_flag_bits
111 #define _(sym, str) TCP_CONN_##sym##_BIT,
112 foreach_tcp_connection_flag
115 } tcp_connection_flag_bits_e;
117 typedef enum _tcp_connection_flag
119 #define _(sym, str) TCP_CONN_##sym = 1 << TCP_CONN_##sym##_BIT,
120 foreach_tcp_connection_flag
123 } tcp_connection_flags_e;
125 /** TCP buffer flags */
126 #define foreach_tcp_buf_flag \
127 _ (ACK) /**< Sending ACK. */ \
128 _ (DUPACK) /**< Sending DUPACK. */ \
132 #define _(f) TCP_BUF_BIT_##f,
140 #define _(f) TCP_BUF_FLAG_##f = 1 << TCP_BUF_BIT_##f,
145 #define TCP_MAX_SACK_BLOCKS 5 /**< Max number of SACK blocks stored */
146 #define TCP_INVALID_SACK_HOLE_INDEX ((u32)~0)
148 typedef struct _sack_scoreboard_hole
150 u32 next; /**< Index for next entry in linked list */
151 u32 prev; /**< Index for previous entry in linked list */
152 u32 start; /**< Start sequence number */
153 u32 end; /**< End sequence number */
154 } sack_scoreboard_hole_t;
156 typedef struct _sack_scoreboard
158 sack_scoreboard_hole_t *holes; /**< Pool of holes */
159 u32 head; /**< Index to first entry */
160 u32 sacked_bytes; /**< Number of bytes sacked in sb */
163 typedef enum _tcp_cc_algorithm_type
166 } tcp_cc_algorithm_type_e;
168 typedef struct _tcp_cc_algorithm tcp_cc_algorithm_t;
170 typedef enum _tcp_cc_ack_t
177 typedef struct _tcp_connection
179 transport_connection_t connection; /**< Common transport data. First! */
181 u8 state; /**< TCP state as per tcp_state_t */
182 u16 flags; /**< Connection flags (see tcp_conn_flags_e) */
183 u32 timers[TCP_N_TIMERS]; /**< Timer handles into timer wheel */
187 /** Send sequence variables RFC793 */
188 u32 snd_una; /**< oldest unacknowledged sequence number */
189 u32 snd_una_max; /**< newest unacknowledged sequence number + 1*/
190 u32 snd_wnd; /**< send window */
191 u32 snd_wl1; /**< seq number used for last snd.wnd update */
192 u32 snd_wl2; /**< ack number used for last snd.wnd update */
193 u32 snd_nxt; /**< next seq number to be sent */
195 /** Receive sequence variables RFC793 */
196 u32 rcv_nxt; /**< next sequence number expected */
197 u32 rcv_wnd; /**< receive window we expect */
199 u32 rcv_las; /**< rcv_nxt at last ack sent/rcv_wnd update */
200 u32 iss; /**< initial sent sequence */
201 u32 irs; /**< initial remote sequence */
204 tcp_options_t opt; /**< TCP connection options parsed */
205 u8 rcv_wscale; /**< Window scale to advertise to peer */
206 u8 snd_wscale; /**< Window scale to use when sending */
207 u32 tsval_recent; /**< Last timestamp received */
208 u32 tsval_recent_age; /**< When last updated tstamp_recent*/
210 sack_block_t *snd_sacks; /**< Vector of SACKs to send. XXX Fixed size? */
211 sack_scoreboard_t sack_sb; /**< SACK "scoreboard" that tracks holes */
213 u8 rcv_dupacks; /**< Number of DUPACKs received */
214 u8 snt_dupacks; /**< Number of DUPACKs sent in a burst */
216 /* Congestion control */
217 u32 cwnd; /**< Congestion window */
218 u32 ssthresh; /**< Slow-start threshold */
219 u32 prev_ssthresh; /**< ssthresh before congestion */
220 u32 bytes_acked; /**< Bytes acknowledged by current segment */
221 u32 rtx_bytes; /**< Retransmitted bytes */
222 u32 tsecr_last_ack; /**< Timestamp echoed to us in last health ACK */
223 tcp_cc_algorithm_t *cc_algo; /**< Congestion control algorithm */
226 u32 rto; /**< Retransmission timeout */
227 u32 rto_boff; /**< Index for RTO backoff */
228 u32 srtt; /**< Smoothed RTT */
229 u32 rttvar; /**< Smoothed mean RTT difference. Approximates variance */
230 u32 rtt_ts; /**< Timestamp for tracked ACK */
231 u32 rtt_seq; /**< Sequence number for tracked ACK */
233 u16 snd_mss; /**< Send MSS */
236 struct _tcp_cc_algorithm
238 void (*rcv_ack) (tcp_connection_t * tc);
239 void (*rcv_cong_ack) (tcp_connection_t * tc, tcp_cc_ack_t ack);
240 void (*congestion) (tcp_connection_t * tc);
241 void (*recovered) (tcp_connection_t * tc);
242 void (*init) (tcp_connection_t * tc);
245 #define tcp_fastrecovery_on(tc) (tc)->flags |= TCP_CONN_FAST_RECOVERY
246 #define tcp_fastrecovery_off(tc) (tc)->flags &= ~TCP_CONN_FAST_RECOVERY
247 #define tcp_in_fastrecovery(tc) ((tc)->flags & TCP_CONN_FAST_RECOVERY)
248 #define tcp_in_recovery(tc) ((tc)->flags & (TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
249 #define tcp_recovery_off(tc) ((tc)->flags &= ~(TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
250 #define tcp_in_slowstart(tc) (tc->cwnd < tc->ssthresh)
259 typedef enum _tcp_error
261 #define tcp_error(n,s) TCP_ERROR_##n,
262 #include <vnet/tcp/tcp_error.def>
267 typedef struct _tcp_lookup_dispatch
270 } tcp_lookup_dispatch_t;
272 typedef struct _tcp_main
274 /* Per-worker thread tcp connection pools */
275 tcp_connection_t **connections;
277 /* Pool of listeners. */
278 tcp_connection_t *listener_pool;
280 /** Dispatch table by state and flags */
281 tcp_lookup_dispatch_t dispatch_table[TCP_N_STATES][64];
283 u8 log2_tstamp_clocks_per_tick;
284 f64 tstamp_ticks_per_clock;
286 /** per-worker tx buffer free lists */
289 /* Per worker-thread timer wheel for connections timers */
290 tw_timer_wheel_16t_2w_512sl_t *timer_wheels;
292 /* Convenience per worker-thread vector of connections to DELACK */
293 u32 **delack_connections;
295 /* Pool of half-open connections on which we've sent a SYN */
296 tcp_connection_t *half_open_connections;
298 /* Pool of local TCP endpoints */
299 transport_endpoint_t *local_endpoints;
301 /* Local endpoints lookup table */
302 transport_endpoint_table_t local_endpoints_table;
304 /* Congestion control algorithms registered */
305 tcp_cc_algorithm_t *cc_algos;
308 vlib_main_t *vlib_main;
309 vnet_main_t *vnet_main;
310 ip4_main_t *ip4_main;
311 ip6_main_t *ip6_main;
314 extern tcp_main_t tcp_main;
315 extern vlib_node_registration_t tcp4_input_node;
316 extern vlib_node_registration_t tcp6_input_node;
317 extern vlib_node_registration_t tcp4_output_node;
318 extern vlib_node_registration_t tcp6_output_node;
320 always_inline tcp_main_t *
326 always_inline tcp_connection_t *
327 tcp_connection_get (u32 conn_index, u32 thread_index)
329 return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
332 always_inline tcp_connection_t *
333 tcp_connection_get_if_valid (u32 conn_index, u32 thread_index)
335 if (tcp_main.connections[thread_index] == 0)
337 if (pool_is_free_index (tcp_main.connections[thread_index], conn_index))
339 return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
342 void tcp_connection_close (tcp_connection_t * tc);
343 void tcp_connection_cleanup (tcp_connection_t * tc);
344 void tcp_connection_del (tcp_connection_t * tc);
346 always_inline tcp_connection_t *
347 tcp_listener_get (u32 tli)
349 return pool_elt_at_index (tcp_main.listener_pool, tli);
352 always_inline tcp_connection_t *
353 tcp_half_open_connection_get (u32 conn_index)
355 return pool_elt_at_index (tcp_main.half_open_connections, conn_index);
358 void tcp_make_ack (tcp_connection_t * ts, vlib_buffer_t * b);
359 void tcp_make_finack (tcp_connection_t * tc, vlib_buffer_t * b);
360 void tcp_make_synack (tcp_connection_t * ts, vlib_buffer_t * b);
361 void tcp_send_reset (vlib_buffer_t * pkt, u8 is_ip4);
362 void tcp_send_syn (tcp_connection_t * tc);
363 void tcp_send_fin (tcp_connection_t * tc);
364 void tcp_set_snd_mss (tcp_connection_t * tc);
367 tcp_end_seq (tcp_header_t * th, u32 len)
369 return th->seq_number + tcp_is_syn (th) + tcp_is_fin (th) + len;
372 /* Modulo arithmetic for TCP sequence numbers */
373 #define seq_lt(_s1, _s2) ((i32)((_s1)-(_s2)) < 0)
374 #define seq_leq(_s1, _s2) ((i32)((_s1)-(_s2)) <= 0)
375 #define seq_gt(_s1, _s2) ((i32)((_s1)-(_s2)) > 0)
376 #define seq_geq(_s1, _s2) ((i32)((_s1)-(_s2)) >= 0)
378 /* Modulo arithmetic for timestamps */
379 #define timestamp_lt(_t1, _t2) ((i32)((_t1)-(_t2)) < 0)
380 #define timestamp_leq(_t1, _t2) ((i32)((_t1)-(_t2)) <= 0)
383 tcp_flight_size (const tcp_connection_t * tc)
385 return tc->snd_una_max - tc->snd_una - tc->sack_sb.sacked_bytes
390 * Initial cwnd as per RFC5681
393 tcp_initial_cwnd (const tcp_connection_t * tc)
395 if (tc->snd_mss > 2190)
396 return 2 * tc->snd_mss;
397 else if (tc->snd_mss > 1095)
398 return 3 * tc->snd_mss;
400 return 4 * tc->snd_mss;
404 tcp_loss_wnd (const tcp_connection_t * tc)
410 tcp_available_wnd (const tcp_connection_t * tc)
412 return clib_min (tc->cwnd, tc->snd_wnd);
416 tcp_available_snd_space (const tcp_connection_t * tc)
418 u32 available_wnd = tcp_available_wnd (tc);
419 u32 flight_size = tcp_flight_size (tc);
421 if (available_wnd <= flight_size)
424 return available_wnd - flight_size;
427 void tcp_retransmit_first_unacked (tcp_connection_t * tc);
429 void tcp_fast_retransmit (tcp_connection_t * tc);
434 return clib_cpu_time_now () * tcp_main.tstamp_ticks_per_clock;
437 u32 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b);
440 tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
443 void tcp_connection_timers_init (tcp_connection_t * tc);
444 void tcp_connection_timers_reset (tcp_connection_t * tc);
446 void tcp_connection_init_vars (tcp_connection_t * tc);
449 tcp_connection_force_ack (tcp_connection_t * tc, vlib_buffer_t * b)
451 /* Reset flags, make sure ack is sent */
452 tc->flags = TCP_CONN_SNDACK;
453 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
457 tcp_timer_set (tcp_connection_t * tc, u8 timer_id, u32 interval)
460 = tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
461 tc->c_c_index, timer_id, interval);
465 tcp_retransmit_timer_set (tcp_main_t * tm, tcp_connection_t * tc)
467 /* XXX Switch to faster TW */
468 tcp_timer_set (tc, TCP_TIMER_RETRANSMIT,
469 clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
473 tcp_timer_reset (tcp_connection_t * tc, u8 timer_id)
475 if (tc->timers[timer_id] == TCP_TIMER_HANDLE_INVALID)
478 tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
479 tc->timers[timer_id]);
480 tc->timers[timer_id] = TCP_TIMER_HANDLE_INVALID;
484 tcp_timer_update (tcp_connection_t * tc, u8 timer_id, u32 interval)
486 if (tc->timers[timer_id] != TCP_TIMER_HANDLE_INVALID)
487 tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
488 tc->timers[timer_id]);
489 tc->timers[timer_id] =
490 tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
491 tc->c_c_index, timer_id, interval);
495 tcp_timer_is_active (tcp_connection_t * tc, tcp_timers_e timer)
497 return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID;
501 scoreboard_remove_hole (sack_scoreboard_t * sb,
502 sack_scoreboard_hole_t * hole);
504 always_inline sack_scoreboard_hole_t *
505 scoreboard_next_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
507 if (hole->next != TCP_INVALID_SACK_HOLE_INDEX)
508 return pool_elt_at_index (sb->holes, hole->next);
512 always_inline sack_scoreboard_hole_t *
513 scoreboard_first_hole (sack_scoreboard_t * sb)
515 if (sb->head != TCP_INVALID_SACK_HOLE_INDEX)
516 return pool_elt_at_index (sb->holes, sb->head);
521 scoreboard_clear (sack_scoreboard_t * sb)
523 sack_scoreboard_hole_t *hole = scoreboard_first_hole (sb);
524 while ((hole = scoreboard_first_hole (sb)))
526 scoreboard_remove_hole (sb, hole);
531 scoreboard_hole_bytes (sack_scoreboard_hole_t * hole)
533 return hole->end - hole->start;
537 tcp_cc_algo_register (tcp_cc_algorithm_type_e type,
538 const tcp_cc_algorithm_t * vft)
540 tcp_main_t *tm = vnet_get_tcp_main ();
541 vec_validate (tm->cc_algos, type);
543 tm->cc_algos[type] = *vft;
546 always_inline tcp_cc_algorithm_t *
547 tcp_cc_algo_get (tcp_cc_algorithm_type_e type)
549 tcp_main_t *tm = vnet_get_tcp_main ();
550 return &tm->cc_algos[type];
553 void tcp_cc_init (tcp_connection_t * tc);
556 * Push TCP header to buffer
558 * @param vm - vlib_main
559 * @param b - buffer to write the header to
560 * @param sp_net - source port net order
561 * @param dp_net - destination port net order
562 * @param seq - sequence number net order
563 * @param ack - ack number net order
564 * @param tcp_hdr_opts_len - header and options length in bytes
565 * @param flags - header flags
566 * @param wnd - window size
568 * @return - pointer to start of TCP header
571 vlib_buffer_push_tcp_net_order (vlib_buffer_t * b, u16 sp, u16 dp, u32 seq,
572 u32 ack, u8 tcp_hdr_opts_len, u8 flags,
577 th = vlib_buffer_push_uninit (b, tcp_hdr_opts_len);
581 th->seq_number = seq;
582 th->ack_number = ack;
583 th->data_offset_and_reserved = (tcp_hdr_opts_len >> 2) << 4;
587 th->urgent_pointer = 0;
592 * Push TCP header to buffer
594 * @param b - buffer to write the header to
595 * @param sp_net - source port net order
596 * @param dp_net - destination port net order
597 * @param seq - sequence number host order
598 * @param ack - ack number host order
599 * @param tcp_hdr_opts_len - header and options length in bytes
600 * @param flags - header flags
601 * @param wnd - window size
603 * @return - pointer to start of TCP header
606 vlib_buffer_push_tcp (vlib_buffer_t * b, u16 sp_net, u16 dp_net, u32 seq,
607 u32 ack, u8 tcp_hdr_opts_len, u8 flags, u16 wnd)
609 return vlib_buffer_push_tcp_net_order (b, sp_net, dp_net,
610 clib_host_to_net_u32 (seq),
611 clib_host_to_net_u32 (ack),
612 tcp_hdr_opts_len, flags,
613 clib_host_to_net_u16 (wnd));
616 #endif /* _vnet_tcp_h_ */
619 * fd.io coding-style-patch-verification: ON
622 * eval: (c-set-style "gnu")