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_DEFAULT_RX_FIFO_SIZE 64 << 10
35 /** TCP FSM state definitions as per RFC793. */
36 #define foreach_tcp_fsm_state \
39 _(SYN_SENT, "SYN_SENT") \
40 _(SYN_RCVD, "SYN_RCVD") \
41 _(ESTABLISHED, "ESTABLISHED") \
42 _(CLOSE_WAIT, "CLOSE_WAIT") \
43 _(FIN_WAIT_1, "FIN_WAIT_1") \
44 _(LAST_ACK, "LAST_ACK") \
45 _(CLOSING, "CLOSING") \
46 _(FIN_WAIT_2, "FIN_WAIT_2") \
47 _(TIME_WAIT, "TIME_WAIT")
49 typedef enum _tcp_state
51 #define _(sym, str) TCP_STATE_##sym,
57 format_function_t format_tcp_state;
60 #define foreach_tcp_timer \
61 _(RETRANSMIT, "RETRANSMIT") \
62 _(DELACK, "DELAYED ACK") \
63 _(PERSIST, "PERSIST") \
66 _(RETRANSMIT_SYN, "RETRANSMIT_SYN") \
67 _(ESTABLISH, "ESTABLISH")
69 typedef enum _tcp_timers
71 #define _(sym, str) TCP_TIMER_##sym,
77 typedef void (timer_expiration_handler) (u32 index);
79 extern timer_expiration_handler tcp_timer_delack_handler;
80 extern timer_expiration_handler tcp_timer_retransmit_handler;
81 extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
83 #define TCP_TIMER_HANDLE_INVALID ((u32) ~0)
85 /* Timer delays as multiples of 100ms */
86 #define TCP_TO_TIMER_TICK TCP_TICK*10 /* Period for converting from TCP
87 * ticks to timer units */
88 #define TCP_DELACK_TIME 1 /* 0.1s */
89 #define TCP_ESTABLISH_TIME 750 /* 75s */
90 #define TCP_2MSL_TIME 300 /* 30s */
92 #define TCP_RTO_MAX 60 * THZ /* Min max RTO (60s) as per RFC6298 */
93 #define TCP_RTT_MAX 30 * THZ /* 30s (probably too much) */
94 #define TCP_RTO_SYN_RETRIES 3 /* SYN retries without doubling RTO */
95 #define TCP_RTO_INIT 1 * THZ /* Initial retransmit timer */
97 void tcp_update_time (f64 now, u32 thread_index);
99 /** TCP connection flags */
100 #define foreach_tcp_connection_flag \
101 _(DELACK, "Delay ACK") \
102 _(SNDACK, "Send ACK") \
103 _(BURSTACK, "Burst ACK set") \
104 _(SENT_RCV_WND0, "Sent 0 receive window") \
105 _(RECOVERY, "Recovery on") \
106 _(FAST_RECOVERY, "Fast Recovery on")
108 typedef enum _tcp_connection_flag_bits
110 #define _(sym, str) TCP_CONN_##sym##_BIT,
111 foreach_tcp_connection_flag
114 } tcp_connection_flag_bits_e;
116 typedef enum _tcp_connection_flag
118 #define _(sym, str) TCP_CONN_##sym = 1 << TCP_CONN_##sym##_BIT,
119 foreach_tcp_connection_flag
122 } tcp_connection_flags_e;
124 /** TCP buffer flags */
125 #define foreach_tcp_buf_flag \
126 _ (ACK) /**< Sending ACK. */ \
127 _ (DUPACK) /**< Sending DUPACK. */ \
131 #define _(f) TCP_BUF_BIT_##f,
139 #define _(f) TCP_BUF_FLAG_##f = 1 << TCP_BUF_BIT_##f,
144 #define TCP_MAX_SACK_BLOCKS 5 /**< Max number of SACK blocks stored */
145 #define TCP_INVALID_SACK_HOLE_INDEX ((u32)~0)
147 typedef struct _sack_scoreboard_hole
149 u32 next; /**< Index for next entry in linked list */
150 u32 prev; /**< Index for previous entry in linked list */
151 u32 start; /**< Start sequence number */
152 u32 end; /**< End sequence number */
153 } sack_scoreboard_hole_t;
155 typedef struct _sack_scoreboard
157 sack_scoreboard_hole_t *holes; /**< Pool of holes */
158 u32 head; /**< Index to first entry */
159 u32 sacked_bytes; /**< Number of bytes sacked in sb */
162 typedef enum _tcp_cc_algorithm_type
165 } tcp_cc_algorithm_type_e;
167 typedef struct _tcp_cc_algorithm tcp_cc_algorithm_t;
169 typedef enum _tcp_cc_ack_t
176 typedef struct _tcp_connection
178 transport_connection_t connection; /**< Common transport data. First! */
180 u8 state; /**< TCP state as per tcp_state_t */
181 u16 flags; /**< Connection flags (see tcp_conn_flags_e) */
182 u32 timers[TCP_N_TIMERS]; /**< Timer handles into timer wheel */
186 /** Send sequence variables RFC793 */
187 u32 snd_una; /**< oldest unacknowledged sequence number */
188 u32 snd_una_max; /**< newest unacknowledged sequence number + 1*/
189 u32 snd_wnd; /**< send window */
190 u32 snd_wl1; /**< seq number used for last snd.wnd update */
191 u32 snd_wl2; /**< ack number used for last snd.wnd update */
192 u32 snd_nxt; /**< next seq number to be sent */
194 /** Receive sequence variables RFC793 */
195 u32 rcv_nxt; /**< next sequence number expected */
196 u32 rcv_wnd; /**< receive window we expect */
198 u32 rcv_las; /**< rcv_nxt at last ack sent/rcv_wnd update */
199 u32 iss; /**< initial sent sequence */
200 u32 irs; /**< initial remote sequence */
203 tcp_options_t opt; /**< TCP connection options parsed */
204 u8 rcv_wscale; /**< Window scale to advertise to peer */
205 u8 snd_wscale; /**< Window scale to use when sending */
206 u32 tsval_recent; /**< Last timestamp received */
207 u32 tsval_recent_age; /**< When last updated tstamp_recent*/
209 sack_block_t *snd_sacks; /**< Vector of SACKs to send. XXX Fixed size? */
210 sack_scoreboard_t sack_sb; /**< SACK "scoreboard" that tracks holes */
212 u8 rcv_dupacks; /**< Number of DUPACKs received */
213 u8 snt_dupacks; /**< Number of DUPACKs sent in a burst */
215 /* Congestion control */
216 u32 cwnd; /**< Congestion window */
217 u32 ssthresh; /**< Slow-start threshold */
218 u32 prev_ssthresh; /**< ssthresh before congestion */
219 u32 bytes_acked; /**< Bytes acknowledged by current segment */
220 u32 rtx_bytes; /**< Retransmitted bytes */
221 u32 tsecr_last_ack; /**< Timestamp echoed to us in last health ACK */
222 tcp_cc_algorithm_t *cc_algo; /**< Congestion control algorithm */
225 u32 rto; /**< Retransmission timeout */
226 u32 rto_boff; /**< Index for RTO backoff */
227 u32 srtt; /**< Smoothed RTT */
228 u32 rttvar; /**< Smoothed mean RTT difference. Approximates variance */
229 u32 rtt_ts; /**< Timestamp for tracked ACK */
230 u32 rtt_seq; /**< Sequence number for tracked ACK */
232 u16 snd_mss; /**< Send MSS */
235 struct _tcp_cc_algorithm
237 void (*rcv_ack) (tcp_connection_t * tc);
238 void (*rcv_cong_ack) (tcp_connection_t * tc, tcp_cc_ack_t ack);
239 void (*congestion) (tcp_connection_t * tc);
240 void (*recovered) (tcp_connection_t * tc);
241 void (*init) (tcp_connection_t * tc);
244 #define tcp_fastrecovery_on(tc) (tc)->flags |= TCP_CONN_FAST_RECOVERY
245 #define tcp_fastrecovery_off(tc) (tc)->flags &= ~TCP_CONN_FAST_RECOVERY
246 #define tcp_in_fastrecovery(tc) ((tc)->flags & TCP_CONN_FAST_RECOVERY)
247 #define tcp_in_recovery(tc) ((tc)->flags & (TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
248 #define tcp_recovery_off(tc) ((tc)->flags &= ~(TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
249 #define tcp_in_slowstart(tc) (tc->cwnd < tc->ssthresh)
258 typedef enum _tcp_error
260 #define tcp_error(n,s) TCP_ERROR_##n,
261 #include <vnet/tcp/tcp_error.def>
266 typedef struct _tcp_lookup_dispatch
269 } tcp_lookup_dispatch_t;
271 typedef struct _tcp_main
273 /* Per-worker thread tcp connection pools */
274 tcp_connection_t **connections;
276 /* Pool of listeners. */
277 tcp_connection_t *listener_pool;
279 /** Dispatch table by state and flags */
280 tcp_lookup_dispatch_t dispatch_table[TCP_N_STATES][64];
282 u8 log2_tstamp_clocks_per_tick;
283 f64 tstamp_ticks_per_clock;
285 /** per-worker tx buffer free lists */
288 /* Per worker-thread timer wheel for connections timers */
289 tw_timer_wheel_16t_2w_512sl_t *timer_wheels;
291 /* Convenience per worker-thread vector of connections to DELACK */
292 u32 **delack_connections;
294 /* Pool of half-open connections on which we've sent a SYN */
295 tcp_connection_t *half_open_connections;
297 /* Pool of local TCP endpoints */
298 transport_endpoint_t *local_endpoints;
300 /* Local endpoints lookup table */
301 transport_endpoint_table_t local_endpoints_table;
303 /* Congestion control algorithms registered */
304 tcp_cc_algorithm_t *cc_algos;
307 vlib_main_t *vlib_main;
308 vnet_main_t *vnet_main;
309 ip4_main_t *ip4_main;
310 ip6_main_t *ip6_main;
313 extern tcp_main_t tcp_main;
314 extern vlib_node_registration_t tcp4_input_node;
315 extern vlib_node_registration_t tcp6_input_node;
316 extern vlib_node_registration_t tcp4_output_node;
317 extern vlib_node_registration_t tcp6_output_node;
319 always_inline tcp_main_t *
325 always_inline tcp_connection_t *
326 tcp_connection_get (u32 conn_index, u32 thread_index)
328 return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
331 always_inline tcp_connection_t *
332 tcp_connection_get_if_valid (u32 conn_index, u32 thread_index)
334 if (tcp_main.connections[thread_index] == 0)
336 if (pool_is_free_index (tcp_main.connections[thread_index], conn_index))
338 return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
341 void tcp_connection_close (tcp_connection_t * tc);
342 void tcp_connection_cleanup (tcp_connection_t * tc);
343 void tcp_connection_del (tcp_connection_t * tc);
345 always_inline tcp_connection_t *
346 tcp_listener_get (u32 tli)
348 return pool_elt_at_index (tcp_main.listener_pool, tli);
351 always_inline tcp_connection_t *
352 tcp_half_open_connection_get (u32 conn_index)
354 return pool_elt_at_index (tcp_main.half_open_connections, conn_index);
357 void tcp_make_ack (tcp_connection_t * ts, vlib_buffer_t * b);
358 void tcp_make_finack (tcp_connection_t * tc, vlib_buffer_t * b);
359 void tcp_make_synack (tcp_connection_t * ts, vlib_buffer_t * b);
360 void tcp_send_reset (vlib_buffer_t * pkt, u8 is_ip4);
361 void tcp_send_syn (tcp_connection_t * tc);
362 void tcp_send_fin (tcp_connection_t * tc);
363 void tcp_set_snd_mss (tcp_connection_t * tc);
366 tcp_end_seq (tcp_header_t * th, u32 len)
368 return th->seq_number + tcp_is_syn (th) + tcp_is_fin (th) + len;
371 /* Modulo arithmetic for TCP sequence numbers */
372 #define seq_lt(_s1, _s2) ((i32)((_s1)-(_s2)) < 0)
373 #define seq_leq(_s1, _s2) ((i32)((_s1)-(_s2)) <= 0)
374 #define seq_gt(_s1, _s2) ((i32)((_s1)-(_s2)) > 0)
375 #define seq_geq(_s1, _s2) ((i32)((_s1)-(_s2)) >= 0)
377 /* Modulo arithmetic for timestamps */
378 #define timestamp_lt(_t1, _t2) ((i32)((_t1)-(_t2)) < 0)
379 #define timestamp_leq(_t1, _t2) ((i32)((_t1)-(_t2)) <= 0)
382 tcp_flight_size (const tcp_connection_t * tc)
384 return tc->snd_una_max - tc->snd_una - tc->sack_sb.sacked_bytes
389 * Initial cwnd as per RFC5681
392 tcp_initial_cwnd (const tcp_connection_t * tc)
394 if (tc->snd_mss > 2190)
395 return 2 * tc->snd_mss;
396 else if (tc->snd_mss > 1095)
397 return 3 * tc->snd_mss;
399 return 4 * tc->snd_mss;
403 tcp_loss_wnd (const tcp_connection_t * tc)
409 tcp_available_wnd (const tcp_connection_t * tc)
411 return clib_min (tc->cwnd, tc->snd_wnd);
415 tcp_available_snd_space (const tcp_connection_t * tc)
417 u32 available_wnd = tcp_available_wnd (tc);
418 u32 flight_size = tcp_flight_size (tc);
420 if (available_wnd <= flight_size)
423 return available_wnd - flight_size;
426 void tcp_retransmit_first_unacked (tcp_connection_t * tc);
428 void tcp_fast_retransmit (tcp_connection_t * tc);
433 return clib_cpu_time_now () * tcp_main.tstamp_ticks_per_clock;
436 u32 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b);
439 tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
442 void tcp_connection_timers_init (tcp_connection_t * tc);
443 void tcp_connection_timers_reset (tcp_connection_t * tc);
445 void tcp_connection_init_vars (tcp_connection_t * tc);
448 tcp_connection_force_ack (tcp_connection_t * tc, vlib_buffer_t * b)
450 /* Reset flags, make sure ack is sent */
451 tc->flags = TCP_CONN_SNDACK;
452 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
456 tcp_timer_set (tcp_connection_t * tc, u8 timer_id, u32 interval)
459 = tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
460 tc->c_c_index, timer_id, interval);
464 tcp_retransmit_timer_set (tcp_main_t * tm, tcp_connection_t * tc)
466 /* XXX Switch to faster TW */
467 tcp_timer_set (tc, TCP_TIMER_RETRANSMIT,
468 clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
472 tcp_timer_reset (tcp_connection_t * tc, u8 timer_id)
474 if (tc->timers[timer_id] == TCP_TIMER_HANDLE_INVALID)
477 tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
478 tc->timers[timer_id]);
479 tc->timers[timer_id] = TCP_TIMER_HANDLE_INVALID;
483 tcp_timer_update (tcp_connection_t * tc, u8 timer_id, u32 interval)
485 if (tc->timers[timer_id] != TCP_TIMER_HANDLE_INVALID)
486 tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
487 tc->timers[timer_id]);
488 tc->timers[timer_id] =
489 tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
490 tc->c_c_index, timer_id, interval);
494 tcp_timer_is_active (tcp_connection_t * tc, tcp_timers_e timer)
496 return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID;
500 scoreboard_remove_hole (sack_scoreboard_t * sb,
501 sack_scoreboard_hole_t * hole);
503 always_inline sack_scoreboard_hole_t *
504 scoreboard_next_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
506 if (hole->next != TCP_INVALID_SACK_HOLE_INDEX)
507 return pool_elt_at_index (sb->holes, hole->next);
511 always_inline sack_scoreboard_hole_t *
512 scoreboard_first_hole (sack_scoreboard_t * sb)
514 if (sb->head != TCP_INVALID_SACK_HOLE_INDEX)
515 return pool_elt_at_index (sb->holes, sb->head);
520 scoreboard_clear (sack_scoreboard_t * sb)
522 sack_scoreboard_hole_t *hole = scoreboard_first_hole (sb);
523 while ((hole = scoreboard_first_hole (sb)))
525 scoreboard_remove_hole (sb, hole);
530 scoreboard_hole_bytes (sack_scoreboard_hole_t * hole)
532 return hole->end - hole->start;
536 tcp_cc_algo_register (tcp_cc_algorithm_type_e type,
537 const tcp_cc_algorithm_t * vft)
539 tcp_main_t *tm = vnet_get_tcp_main ();
540 vec_validate (tm->cc_algos, type);
542 tm->cc_algos[type] = *vft;
545 always_inline tcp_cc_algorithm_t *
546 tcp_cc_algo_get (tcp_cc_algorithm_type_e type)
548 tcp_main_t *tm = vnet_get_tcp_main ();
549 return &tm->cc_algos[type];
552 void tcp_cc_init (tcp_connection_t * tc);
555 * Push TCP header to buffer
557 * @param vm - vlib_main
558 * @param b - buffer to write the header to
559 * @param sp_net - source port net order
560 * @param dp_net - destination port net order
561 * @param seq - sequence number net order
562 * @param ack - ack number net order
563 * @param tcp_hdr_opts_len - header and options length in bytes
564 * @param flags - header flags
565 * @param wnd - window size
567 * @return - pointer to start of TCP header
570 vlib_buffer_push_tcp_net_order (vlib_buffer_t * b, u16 sp, u16 dp, u32 seq,
571 u32 ack, u8 tcp_hdr_opts_len, u8 flags,
576 th = vlib_buffer_push_uninit (b, tcp_hdr_opts_len);
580 th->seq_number = seq;
581 th->ack_number = ack;
582 th->data_offset_and_reserved = (tcp_hdr_opts_len >> 2) << 4;
586 th->urgent_pointer = 0;
591 * Push TCP header to buffer
593 * @param vm - vlib_main
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")