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>
25 #include <vnet/tcp/tcp_debug.h>
27 #define TCP_TICK 10e-3 /**< TCP tick period (s) */
28 #define THZ 1/TCP_TICK /**< TCP tick frequency */
29 #define TCP_TSTAMP_RESOLUTION TCP_TICK /**< Time stamp resolution */
30 #define TCP_PAWS_IDLE 24 * 24 * 60 * 60 * THZ /**< 24 days */
31 #define TCP_MAX_OPTION_SPACE 40
33 #define TCP_DUPACK_THRESHOLD 3
34 #define TCP_MAX_RX_FIFO_SIZE 2 << 20
35 #define TCP_IW_N_SEGMENTS 10
37 /** TCP FSM state definitions as per RFC793. */
38 #define foreach_tcp_fsm_state \
41 _(SYN_SENT, "SYN_SENT") \
42 _(SYN_RCVD, "SYN_RCVD") \
43 _(ESTABLISHED, "ESTABLISHED") \
44 _(CLOSE_WAIT, "CLOSE_WAIT") \
45 _(FIN_WAIT_1, "FIN_WAIT_1") \
46 _(LAST_ACK, "LAST_ACK") \
47 _(CLOSING, "CLOSING") \
48 _(FIN_WAIT_2, "FIN_WAIT_2") \
49 _(TIME_WAIT, "TIME_WAIT")
51 typedef enum _tcp_state
53 #define _(sym, str) TCP_STATE_##sym,
59 format_function_t format_tcp_state;
62 #define foreach_tcp_timer \
63 _(RETRANSMIT, "RETRANSMIT") \
64 _(DELACK, "DELAYED ACK") \
65 _(PERSIST, "PERSIST") \
67 _(WAITCLOSE, "WAIT CLOSE") \
68 _(RETRANSMIT_SYN, "RETRANSMIT SYN") \
69 _(ESTABLISH, "ESTABLISH")
71 typedef enum _tcp_timers
73 #define _(sym, str) TCP_TIMER_##sym,
79 typedef void (timer_expiration_handler) (u32 index);
81 extern timer_expiration_handler tcp_timer_delack_handler;
82 extern timer_expiration_handler tcp_timer_retransmit_handler;
83 extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
85 #define TCP_TIMER_HANDLE_INVALID ((u32) ~0)
87 /* Timer delays as multiples of 100ms */
88 #define TCP_TO_TIMER_TICK TCP_TICK*10 /* Period for converting from TCP
89 * ticks to timer units */
90 #define TCP_DELACK_TIME 1 /* 0.1s */
91 #define TCP_ESTABLISH_TIME 750 /* 75s */
92 #define TCP_2MSL_TIME 300 /* 30s */
93 #define TCP_CLOSEWAIT_TIME 1 /* 0.1s */
94 #define TCP_CLEANUP_TIME 5 /* 0.5s Time to wait before cleanup */
96 #define TCP_RTO_MAX 60 * THZ /* Min max RTO (60s) as per RFC6298 */
97 #define TCP_RTT_MAX 30 * THZ /* 30s (probably too much) */
98 #define TCP_RTO_SYN_RETRIES 3 /* SYN retries without doubling RTO */
99 #define TCP_RTO_INIT 1 * THZ /* Initial retransmit timer */
101 void tcp_update_time (f64 now, u32 thread_index);
103 /** TCP connection flags */
104 #define foreach_tcp_connection_flag \
105 _(DELACK, "Delay ACK") \
106 _(SNDACK, "Send ACK") \
107 _(BURSTACK, "Burst ACK set") \
108 _(FINSNT, "FIN sent") \
109 _(SENT_RCV_WND0, "Sent 0 receive window") \
110 _(RECOVERY, "Recovery on") \
111 _(FAST_RECOVERY, "Fast Recovery on")
113 typedef enum _tcp_connection_flag_bits
115 #define _(sym, str) TCP_CONN_##sym##_BIT,
116 foreach_tcp_connection_flag
119 } tcp_connection_flag_bits_e;
121 typedef enum _tcp_connection_flag
123 #define _(sym, str) TCP_CONN_##sym = 1 << TCP_CONN_##sym##_BIT,
124 foreach_tcp_connection_flag
127 } tcp_connection_flags_e;
129 /** TCP buffer flags */
130 #define foreach_tcp_buf_flag \
131 _ (ACK) /**< Sending ACK. */ \
132 _ (DUPACK) /**< Sending DUPACK. */ \
136 #define _(f) TCP_BUF_BIT_##f,
144 #define _(f) TCP_BUF_FLAG_##f = 1 << TCP_BUF_BIT_##f,
149 #define TCP_MAX_SACK_BLOCKS 5 /**< Max number of SACK blocks stored */
150 #define TCP_INVALID_SACK_HOLE_INDEX ((u32)~0)
152 typedef struct _sack_scoreboard_hole
154 u32 next; /**< Index for next entry in linked list */
155 u32 prev; /**< Index for previous entry in linked list */
156 u32 start; /**< Start sequence number */
157 u32 end; /**< End sequence number */
158 } sack_scoreboard_hole_t;
160 typedef struct _sack_scoreboard
162 sack_scoreboard_hole_t *holes; /**< Pool of holes */
163 u32 head; /**< Index to first entry */
164 u32 sacked_bytes; /**< Number of bytes sacked in sb */
167 typedef enum _tcp_cc_algorithm_type
170 } tcp_cc_algorithm_type_e;
172 typedef struct _tcp_cc_algorithm tcp_cc_algorithm_t;
174 typedef enum _tcp_cc_ack_t
181 typedef struct _tcp_connection
183 transport_connection_t connection; /**< Common transport data. First! */
185 u8 state; /**< TCP state as per tcp_state_t */
186 u16 flags; /**< Connection flags (see tcp_conn_flags_e) */
187 u32 timers[TCP_N_TIMERS]; /**< Timer handles into timer wheel */
191 /** Send sequence variables RFC793 */
192 u32 snd_una; /**< oldest unacknowledged sequence number */
193 u32 snd_una_max; /**< newest unacknowledged sequence number + 1*/
194 u32 snd_wnd; /**< send window */
195 u32 snd_wl1; /**< seq number used for last snd.wnd update */
196 u32 snd_wl2; /**< ack number used for last snd.wnd update */
197 u32 snd_nxt; /**< next seq number to be sent */
199 /** Receive sequence variables RFC793 */
200 u32 rcv_nxt; /**< next sequence number expected */
201 u32 rcv_wnd; /**< receive window we expect */
203 u32 rcv_las; /**< rcv_nxt at last ack sent/rcv_wnd update */
204 u32 iss; /**< initial sent sequence */
205 u32 irs; /**< initial remote sequence */
208 tcp_options_t opt; /**< TCP connection options parsed */
209 u8 rcv_wscale; /**< Window scale to advertise to peer */
210 u8 snd_wscale; /**< Window scale to use when sending */
211 u32 tsval_recent; /**< Last timestamp received */
212 u32 tsval_recent_age; /**< When last updated tstamp_recent*/
214 sack_block_t *snd_sacks; /**< Vector of SACKs to send. XXX Fixed size? */
215 sack_scoreboard_t sack_sb; /**< SACK "scoreboard" that tracks holes */
217 u8 rcv_dupacks; /**< Number of DUPACKs received */
218 u8 snt_dupacks; /**< Number of DUPACKs sent in a burst */
220 /* Congestion control */
221 u32 cwnd; /**< Congestion window */
222 u32 ssthresh; /**< Slow-start threshold */
223 u32 prev_ssthresh; /**< ssthresh before congestion */
224 u32 bytes_acked; /**< Bytes acknowledged by current segment */
225 u32 rtx_bytes; /**< Retransmitted bytes */
226 u32 tsecr_last_ack; /**< Timestamp echoed to us in last healthy ACK */
227 tcp_cc_algorithm_t *cc_algo; /**< Congestion control algorithm */
230 u32 rto; /**< Retransmission timeout */
231 u32 rto_boff; /**< Index for RTO backoff */
232 u32 srtt; /**< Smoothed RTT */
233 u32 rttvar; /**< Smoothed mean RTT difference. Approximates variance */
234 u32 rtt_ts; /**< Timestamp for tracked ACK */
235 u32 rtt_seq; /**< Sequence number for tracked ACK */
237 u16 snd_mss; /**< Send MSS */
240 struct _tcp_cc_algorithm
242 void (*rcv_ack) (tcp_connection_t * tc);
243 void (*rcv_cong_ack) (tcp_connection_t * tc, tcp_cc_ack_t ack);
244 void (*congestion) (tcp_connection_t * tc);
245 void (*recovered) (tcp_connection_t * tc);
246 void (*init) (tcp_connection_t * tc);
249 #define tcp_fastrecovery_on(tc) (tc)->flags |= TCP_CONN_FAST_RECOVERY
250 #define tcp_fastrecovery_off(tc) (tc)->flags &= ~TCP_CONN_FAST_RECOVERY
251 #define tcp_in_fastrecovery(tc) ((tc)->flags & TCP_CONN_FAST_RECOVERY)
252 #define tcp_in_recovery(tc) ((tc)->flags & (TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
253 #define tcp_recovery_off(tc) ((tc)->flags &= ~(TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
254 #define tcp_in_slowstart(tc) (tc->cwnd < tc->ssthresh)
263 typedef enum _tcp_error
265 #define tcp_error(n,s) TCP_ERROR_##n,
266 #include <vnet/tcp/tcp_error.def>
271 typedef struct _tcp_lookup_dispatch
274 } tcp_lookup_dispatch_t;
276 typedef struct _tcp_main
278 /* Per-worker thread tcp connection pools */
279 tcp_connection_t **connections;
281 /* Pool of listeners. */
282 tcp_connection_t *listener_pool;
284 /** Dispatch table by state and flags */
285 tcp_lookup_dispatch_t dispatch_table[TCP_N_STATES][64];
287 u8 log2_tstamp_clocks_per_tick;
288 f64 tstamp_ticks_per_clock;
290 /** per-worker tx buffer free lists */
293 /* Per worker-thread timer wheel for connections timers */
294 tw_timer_wheel_16t_2w_512sl_t *timer_wheels;
296 /* Convenience per worker-thread vector of connections to DELACK */
297 u32 **delack_connections;
299 /* Pool of half-open connections on which we've sent a SYN */
300 tcp_connection_t *half_open_connections;
302 /* Pool of local TCP endpoints */
303 transport_endpoint_t *local_endpoints;
305 /* Local endpoints lookup table */
306 transport_endpoint_table_t local_endpoints_table;
308 /* Congestion control algorithms registered */
309 tcp_cc_algorithm_t *cc_algos;
311 /* Flag that indicates if stack is on or off */
315 vlib_main_t *vlib_main;
316 vnet_main_t *vnet_main;
317 ip4_main_t *ip4_main;
318 ip6_main_t *ip6_main;
321 extern tcp_main_t tcp_main;
322 extern vlib_node_registration_t tcp4_input_node;
323 extern vlib_node_registration_t tcp6_input_node;
324 extern vlib_node_registration_t tcp4_output_node;
325 extern vlib_node_registration_t tcp6_output_node;
327 always_inline tcp_main_t *
333 clib_error_t *vnet_tcp_enable_disable (vlib_main_t * vm, u8 is_en);
335 always_inline tcp_connection_t *
336 tcp_connection_get (u32 conn_index, u32 thread_index)
338 if (pool_is_free_index (tcp_main.connections[thread_index], conn_index))
340 return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
343 always_inline tcp_connection_t *
344 tcp_connection_get_if_valid (u32 conn_index, u32 thread_index)
346 if (tcp_main.connections[thread_index] == 0)
348 if (pool_is_free_index (tcp_main.connections[thread_index], conn_index))
350 return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
353 void tcp_connection_close (tcp_connection_t * tc);
354 void tcp_connection_cleanup (tcp_connection_t * tc);
355 void tcp_connection_del (tcp_connection_t * tc);
356 void tcp_connection_reset (tcp_connection_t * tc);
358 u8 *format_tcp_connection (u8 * s, va_list * args);
359 u8 *format_tcp_connection_verbose (u8 * s, va_list * args);
361 always_inline tcp_connection_t *
362 tcp_listener_get (u32 tli)
364 return pool_elt_at_index (tcp_main.listener_pool, tli);
367 always_inline tcp_connection_t *
368 tcp_half_open_connection_get (u32 conn_index)
370 return pool_elt_at_index (tcp_main.half_open_connections, conn_index);
373 void tcp_make_ack (tcp_connection_t * ts, vlib_buffer_t * b);
374 void tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b);
375 void tcp_make_synack (tcp_connection_t * ts, vlib_buffer_t * b);
376 void tcp_send_reset (vlib_buffer_t * pkt, u8 is_ip4);
377 void tcp_send_syn (tcp_connection_t * tc);
378 void tcp_send_fin (tcp_connection_t * tc);
379 void tcp_set_snd_mss (tcp_connection_t * tc);
382 tcp_end_seq (tcp_header_t * th, u32 len)
384 return th->seq_number + tcp_is_syn (th) + tcp_is_fin (th) + len;
387 /* Modulo arithmetic for TCP sequence numbers */
388 #define seq_lt(_s1, _s2) ((i32)((_s1)-(_s2)) < 0)
389 #define seq_leq(_s1, _s2) ((i32)((_s1)-(_s2)) <= 0)
390 #define seq_gt(_s1, _s2) ((i32)((_s1)-(_s2)) > 0)
391 #define seq_geq(_s1, _s2) ((i32)((_s1)-(_s2)) >= 0)
393 /* Modulo arithmetic for timestamps */
394 #define timestamp_lt(_t1, _t2) ((i32)((_t1)-(_t2)) < 0)
395 #define timestamp_leq(_t1, _t2) ((i32)((_t1)-(_t2)) <= 0)
398 tcp_flight_size (const tcp_connection_t * tc)
400 return tc->snd_una_max - tc->snd_una - tc->sack_sb.sacked_bytes
405 * Initial cwnd as per RFC5681
408 tcp_initial_cwnd (const tcp_connection_t * tc)
410 if (tc->snd_mss > 2190)
411 return 2 * tc->snd_mss;
412 else if (tc->snd_mss > 1095)
413 return 3 * tc->snd_mss;
415 return 4 * tc->snd_mss;
419 tcp_loss_wnd (const tcp_connection_t * tc)
425 tcp_available_wnd (const tcp_connection_t * tc)
427 return clib_min (tc->cwnd, tc->snd_wnd);
431 tcp_available_snd_space (const tcp_connection_t * tc)
433 u32 available_wnd = tcp_available_wnd (tc);
434 u32 flight_size = tcp_flight_size (tc);
436 if (available_wnd <= flight_size)
439 return available_wnd - flight_size;
442 void tcp_retransmit_first_unacked (tcp_connection_t * tc);
444 void tcp_fast_retransmit (tcp_connection_t * tc);
449 return clib_cpu_time_now () * tcp_main.tstamp_ticks_per_clock;
452 u32 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b);
455 tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
458 void tcp_connection_timers_init (tcp_connection_t * tc);
459 void tcp_connection_timers_reset (tcp_connection_t * tc);
461 void tcp_connection_init_vars (tcp_connection_t * tc);
464 tcp_connection_force_ack (tcp_connection_t * tc, vlib_buffer_t * b)
466 /* Reset flags, make sure ack is sent */
467 tc->flags = TCP_CONN_SNDACK;
468 vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
472 tcp_timer_set (tcp_connection_t * tc, u8 timer_id, u32 interval)
475 = tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
476 tc->c_c_index, timer_id, interval);
480 tcp_retransmit_timer_set (tcp_connection_t * tc)
482 /* XXX Switch to faster TW */
483 tcp_timer_set (tc, TCP_TIMER_RETRANSMIT,
484 clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
488 tcp_timer_reset (tcp_connection_t * tc, u8 timer_id)
490 if (tc->timers[timer_id] == TCP_TIMER_HANDLE_INVALID)
493 tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
494 tc->timers[timer_id]);
495 tc->timers[timer_id] = TCP_TIMER_HANDLE_INVALID;
499 tcp_timer_update (tcp_connection_t * tc, u8 timer_id, u32 interval)
501 if (tc->timers[timer_id] != TCP_TIMER_HANDLE_INVALID)
502 tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
503 tc->timers[timer_id]);
504 tc->timers[timer_id] =
505 tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
506 tc->c_c_index, timer_id, interval);
510 tcp_timer_is_active (tcp_connection_t * tc, tcp_timers_e timer)
512 return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID;
516 scoreboard_remove_hole (sack_scoreboard_t * sb,
517 sack_scoreboard_hole_t * hole);
519 always_inline sack_scoreboard_hole_t *
520 scoreboard_next_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
522 if (hole->next != TCP_INVALID_SACK_HOLE_INDEX)
523 return pool_elt_at_index (sb->holes, hole->next);
527 always_inline sack_scoreboard_hole_t *
528 scoreboard_first_hole (sack_scoreboard_t * sb)
530 if (sb->head != TCP_INVALID_SACK_HOLE_INDEX)
531 return pool_elt_at_index (sb->holes, sb->head);
536 scoreboard_clear (sack_scoreboard_t * sb)
538 sack_scoreboard_hole_t *hole = scoreboard_first_hole (sb);
539 while ((hole = scoreboard_first_hole (sb)))
541 scoreboard_remove_hole (sb, hole);
546 scoreboard_hole_bytes (sack_scoreboard_hole_t * hole)
548 return hole->end - hole->start;
552 tcp_cc_algo_register (tcp_cc_algorithm_type_e type,
553 const tcp_cc_algorithm_t * vft)
555 tcp_main_t *tm = vnet_get_tcp_main ();
556 vec_validate (tm->cc_algos, type);
558 tm->cc_algos[type] = *vft;
561 always_inline tcp_cc_algorithm_t *
562 tcp_cc_algo_get (tcp_cc_algorithm_type_e type)
564 tcp_main_t *tm = vnet_get_tcp_main ();
565 return &tm->cc_algos[type];
568 void tcp_cc_init (tcp_connection_t * tc);
571 * Push TCP header to buffer
573 * @param vm - vlib_main
574 * @param b - buffer to write the header to
575 * @param sp_net - source port net order
576 * @param dp_net - destination port net order
577 * @param seq - sequence number net order
578 * @param ack - ack number net order
579 * @param tcp_hdr_opts_len - header and options length in bytes
580 * @param flags - header flags
581 * @param wnd - window size
583 * @return - pointer to start of TCP header
586 vlib_buffer_push_tcp_net_order (vlib_buffer_t * b, u16 sp, u16 dp, u32 seq,
587 u32 ack, u8 tcp_hdr_opts_len, u8 flags,
592 th = vlib_buffer_push_uninit (b, tcp_hdr_opts_len);
596 th->seq_number = seq;
597 th->ack_number = ack;
598 th->data_offset_and_reserved = (tcp_hdr_opts_len >> 2) << 4;
602 th->urgent_pointer = 0;
607 * Push TCP header to buffer
609 * @param b - buffer to write the header to
610 * @param sp_net - source port net order
611 * @param dp_net - destination port net order
612 * @param seq - sequence number host order
613 * @param ack - ack number host order
614 * @param tcp_hdr_opts_len - header and options length in bytes
615 * @param flags - header flags
616 * @param wnd - window size
618 * @return - pointer to start of TCP header
621 vlib_buffer_push_tcp (vlib_buffer_t * b, u16 sp_net, u16 dp_net, u32 seq,
622 u32 ack, u8 tcp_hdr_opts_len, u8 flags, u16 wnd)
624 return vlib_buffer_push_tcp_net_order (b, sp_net, dp_net,
625 clib_host_to_net_u32 (seq),
626 clib_host_to_net_u32 (ack),
627 tcp_hdr_opts_len, flags,
628 clib_host_to_net_u16 (wnd));
631 #endif /* _vnet_tcp_h_ */
634 * fd.io coding-style-patch-verification: ON
637 * eval: (c-set-style "gnu")