2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Definitions for the TCP module.
8 * Version: @(#)tcp.h 1.0.5 05/23/93
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
21 #define FASTRETRANS_DEBUG 1
23 #include <linux/list.h>
24 #include <linux/tcp.h>
25 #include <linux/bug.h>
26 #include <linux/slab.h>
27 #include <linux/cache.h>
28 #include <linux/percpu.h>
29 #include <linux/skbuff.h>
30 #include <linux/cryptohash.h>
31 #include <linux/kref.h>
32 #include <linux/ktime.h>
34 #include <net/inet_connection_sock.h>
35 #include <net/inet_timewait_sock.h>
36 #include <net/inet_hashtables.h>
37 #include <net/checksum.h>
38 #include <net/request_sock.h>
42 #include <net/tcp_states.h>
43 #include <net/inet_ecn.h>
46 #include <linux/seq_file.h>
47 #include <linux/memcontrol.h>
48 #include <linux/bpf-cgroup.h>
50 extern struct inet_hashinfo tcp_hashinfo
;
52 extern struct percpu_counter tcp_orphan_count
;
53 void tcp_time_wait(struct sock
*sk
, int state
, int timeo
);
55 #define MAX_TCP_HEADER (128 + MAX_HEADER)
56 #define MAX_TCP_OPTION_SPACE 40
57 #define TCP_MIN_SND_MSS 48
58 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
61 * Never offer a window over 32767 without using window scaling. Some
62 * poor stacks do signed 16bit maths!
64 #define MAX_TCP_WINDOW 32767U
66 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
67 #define TCP_MIN_MSS 88U
69 /* The least MTU to use for probing */
70 #define TCP_BASE_MSS 1024
72 /* probing interval, default to 10 minutes as per RFC4821 */
73 #define TCP_PROBE_INTERVAL 600
75 /* Specify interval when tcp mtu probing will stop */
76 #define TCP_PROBE_THRESHOLD 8
78 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
79 #define TCP_FASTRETRANS_THRESH 3
81 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
82 #define TCP_MAX_QUICKACKS 16U
84 /* Maximal number of window scale according to RFC1323 */
85 #define TCP_MAX_WSCALE 14U
88 #define TCP_URG_VALID 0x0100
89 #define TCP_URG_NOTYET 0x0200
90 #define TCP_URG_READ 0x0400
92 #define TCP_RETR1 3 /*
93 * This is how many retries it does before it
94 * tries to figure out if the gateway is
95 * down. Minimal RFC value is 3; it corresponds
96 * to ~3sec-8min depending on RTO.
99 #define TCP_RETR2 15 /*
100 * This should take at least
101 * 90 minutes to time out.
102 * RFC1122 says that the limit is 100 sec.
103 * 15 is ~13-30min depending on RTO.
106 #define TCP_SYN_RETRIES 6 /* This is how many retries are done
107 * when active opening a connection.
108 * RFC1122 says the minimum retry MUST
109 * be at least 180secs. Nevertheless
110 * this value is corresponding to
111 * 63secs of retransmission with the
112 * current initial RTO.
115 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done
116 * when passive opening a connection.
117 * This is corresponding to 31secs of
118 * retransmission with the current
122 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
123 * state, about 60 seconds */
124 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
125 /* BSD style FIN_WAIT2 deadlock breaker.
126 * It used to be 3min, new value is 60sec,
127 * to combine FIN-WAIT-2 timeout with
131 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
133 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
134 #define TCP_ATO_MIN ((unsigned)(HZ/25))
136 #define TCP_DELACK_MIN 4U
137 #define TCP_ATO_MIN 4U
139 #define TCP_RTO_MAX ((unsigned)(120*HZ))
140 #define TCP_RTO_MIN ((unsigned)(HZ/5))
141 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */
142 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */
143 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now
144 * used as a fallback RTO for the
145 * initial data transmission if no
146 * valid RTT sample has been acquired,
147 * most likely due to retrans in 3WHS.
150 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
151 * for local resources.
153 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
154 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
155 #define TCP_KEEPALIVE_INTVL (75*HZ)
157 #define MAX_TCP_KEEPIDLE 32767
158 #define MAX_TCP_KEEPINTVL 32767
159 #define MAX_TCP_KEEPCNT 127
160 #define MAX_TCP_SYNCNT 127
162 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
164 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
165 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
166 * after this time. It should be equal
167 * (or greater than) TCP_TIMEWAIT_LEN
168 * to provide reliability equal to one
169 * provided by timewait state.
171 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
172 * timestamps. It must be less than
173 * minimal timewait lifetime.
179 #define TCPOPT_NOP 1 /* Padding */
180 #define TCPOPT_EOL 0 /* End of options */
181 #define TCPOPT_MSS 2 /* Segment size negotiating */
182 #define TCPOPT_WINDOW 3 /* Window scaling */
183 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
184 #define TCPOPT_SACK 5 /* SACK Block */
185 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
186 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
187 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
188 #define TCPOPT_EXP 254 /* Experimental */
189 /* Magic number to be after the option value for sharing TCP
190 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
192 #define TCPOPT_FASTOPEN_MAGIC 0xF989
193 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9
199 #define TCPOLEN_MSS 4
200 #define TCPOLEN_WINDOW 3
201 #define TCPOLEN_SACK_PERM 2
202 #define TCPOLEN_TIMESTAMP 10
203 #define TCPOLEN_MD5SIG 18
204 #define TCPOLEN_FASTOPEN_BASE 2
205 #define TCPOLEN_EXP_FASTOPEN_BASE 4
206 #define TCPOLEN_EXP_SMC_BASE 6
208 /* But this is what stacks really send out. */
209 #define TCPOLEN_TSTAMP_ALIGNED 12
210 #define TCPOLEN_WSCALE_ALIGNED 4
211 #define TCPOLEN_SACKPERM_ALIGNED 4
212 #define TCPOLEN_SACK_BASE 2
213 #define TCPOLEN_SACK_BASE_ALIGNED 4
214 #define TCPOLEN_SACK_PERBLOCK 8
215 #define TCPOLEN_MD5SIG_ALIGNED 20
216 #define TCPOLEN_MSS_ALIGNED 4
217 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8
219 /* Flags in tp->nonagle */
220 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
221 #define TCP_NAGLE_CORK 2 /* Socket is corked */
222 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
224 /* TCP thin-stream limits */
225 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
227 /* TCP initial congestion window as per rfc6928 */
228 #define TCP_INIT_CWND 10
230 /* Bit Flags for sysctl_tcp_fastopen */
231 #define TFO_CLIENT_ENABLE 1
232 #define TFO_SERVER_ENABLE 2
233 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */
235 /* Accept SYN data w/o any cookie option */
236 #define TFO_SERVER_COOKIE_NOT_REQD 0x200
238 /* Force enable TFO on all listeners, i.e., not requiring the
239 * TCP_FASTOPEN socket option.
241 #define TFO_SERVER_WO_SOCKOPT1 0x400
244 /* sysctl variables for tcp */
245 extern int sysctl_tcp_max_orphans
;
246 extern long sysctl_tcp_mem
[3];
248 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */
249 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */
251 extern atomic_long_t tcp_memory_allocated
;
252 extern struct percpu_counter tcp_sockets_allocated
;
253 extern unsigned long tcp_memory_pressure
;
255 /* optimized version of sk_under_memory_pressure() for TCP sockets */
256 static inline bool tcp_under_memory_pressure(const struct sock
*sk
)
258 if (mem_cgroup_sockets_enabled
&& sk
->sk_memcg
&&
259 mem_cgroup_under_socket_pressure(sk
->sk_memcg
))
262 return tcp_memory_pressure
;
265 * The next routines deal with comparing 32 bit unsigned ints
266 * and worry about wraparound (automatic with unsigned arithmetic).
269 static inline bool before(__u32 seq1
, __u32 seq2
)
271 return (__s32
)(seq1
-seq2
) < 0;
273 #define after(seq2, seq1) before(seq1, seq2)
275 /* is s2<=s1<=s3 ? */
276 static inline bool between(__u32 seq1
, __u32 seq2
, __u32 seq3
)
278 return seq3
- seq2
>= seq1
- seq2
;
281 static inline bool tcp_out_of_memory(struct sock
*sk
)
283 if (sk
->sk_wmem_queued
> SOCK_MIN_SNDBUF
&&
284 sk_memory_allocated(sk
) > sk_prot_mem_limits(sk
, 2))
289 void sk_forced_mem_schedule(struct sock
*sk
, int size
);
291 static inline bool tcp_too_many_orphans(struct sock
*sk
, int shift
)
293 struct percpu_counter
*ocp
= sk
->sk_prot
->orphan_count
;
294 int orphans
= percpu_counter_read_positive(ocp
);
296 if (orphans
<< shift
> sysctl_tcp_max_orphans
) {
297 orphans
= percpu_counter_sum_positive(ocp
);
298 if (orphans
<< shift
> sysctl_tcp_max_orphans
)
304 bool tcp_check_oom(struct sock
*sk
, int shift
);
307 extern struct proto tcp_prot
;
309 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
310 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field)
311 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
312 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
314 void tcp_tasklet_init(void);
316 void tcp_v4_err(struct sk_buff
*skb
, u32
);
318 void tcp_shutdown(struct sock
*sk
, int how
);
320 int tcp_v4_early_demux(struct sk_buff
*skb
);
321 int tcp_v4_rcv(struct sk_buff
*skb
);
323 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock
*tw
);
324 int tcp_sendmsg(struct sock
*sk
, struct msghdr
*msg
, size_t size
);
325 int tcp_sendmsg_locked(struct sock
*sk
, struct msghdr
*msg
, size_t size
);
326 int tcp_sendpage(struct sock
*sk
, struct page
*page
, int offset
, size_t size
,
328 int tcp_sendpage_locked(struct sock
*sk
, struct page
*page
, int offset
,
329 size_t size
, int flags
);
330 ssize_t
do_tcp_sendpages(struct sock
*sk
, struct page
*page
, int offset
,
331 size_t size
, int flags
);
332 void tcp_release_cb(struct sock
*sk
);
333 void tcp_wfree(struct sk_buff
*skb
);
334 void tcp_write_timer_handler(struct sock
*sk
);
335 void tcp_delack_timer_handler(struct sock
*sk
);
336 int tcp_ioctl(struct sock
*sk
, int cmd
, unsigned long arg
);
337 int tcp_rcv_state_process(struct sock
*sk
, struct sk_buff
*skb
);
338 void tcp_rcv_established(struct sock
*sk
, struct sk_buff
*skb
,
339 const struct tcphdr
*th
);
340 void tcp_rcv_space_adjust(struct sock
*sk
);
341 int tcp_twsk_unique(struct sock
*sk
, struct sock
*sktw
, void *twp
);
342 void tcp_twsk_destructor(struct sock
*sk
);
343 ssize_t
tcp_splice_read(struct socket
*sk
, loff_t
*ppos
,
344 struct pipe_inode_info
*pipe
, size_t len
,
347 void tcp_enter_quickack_mode(struct sock
*sk
, unsigned int max_quickacks
);
348 static inline void tcp_dec_quickack_mode(struct sock
*sk
,
349 const unsigned int pkts
)
351 struct inet_connection_sock
*icsk
= inet_csk(sk
);
353 if (icsk
->icsk_ack
.quick
) {
354 if (pkts
>= icsk
->icsk_ack
.quick
) {
355 icsk
->icsk_ack
.quick
= 0;
356 /* Leaving quickack mode we deflate ATO. */
357 icsk
->icsk_ack
.ato
= TCP_ATO_MIN
;
359 icsk
->icsk_ack
.quick
-= pkts
;
364 #define TCP_ECN_QUEUE_CWR 2
365 #define TCP_ECN_DEMAND_CWR 4
366 #define TCP_ECN_SEEN 8
376 enum tcp_tw_status
tcp_timewait_state_process(struct inet_timewait_sock
*tw
,
378 const struct tcphdr
*th
);
379 struct sock
*tcp_check_req(struct sock
*sk
, struct sk_buff
*skb
,
380 struct request_sock
*req
, bool fastopen
);
381 int tcp_child_process(struct sock
*parent
, struct sock
*child
,
382 struct sk_buff
*skb
);
383 void tcp_enter_loss(struct sock
*sk
);
384 void tcp_cwnd_reduction(struct sock
*sk
, int newly_acked_sacked
, int flag
);
385 void tcp_clear_retrans(struct tcp_sock
*tp
);
386 void tcp_update_metrics(struct sock
*sk
);
387 void tcp_init_metrics(struct sock
*sk
);
388 void tcp_metrics_init(void);
389 bool tcp_peer_is_proven(struct request_sock
*req
, struct dst_entry
*dst
);
390 void tcp_close(struct sock
*sk
, long timeout
);
391 void tcp_init_sock(struct sock
*sk
);
392 void tcp_init_transfer(struct sock
*sk
, int bpf_op
);
393 unsigned int tcp_poll(struct file
*file
, struct socket
*sock
,
394 struct poll_table_struct
*wait
);
395 int tcp_getsockopt(struct sock
*sk
, int level
, int optname
,
396 char __user
*optval
, int __user
*optlen
);
397 int tcp_setsockopt(struct sock
*sk
, int level
, int optname
,
398 char __user
*optval
, unsigned int optlen
);
399 int compat_tcp_getsockopt(struct sock
*sk
, int level
, int optname
,
400 char __user
*optval
, int __user
*optlen
);
401 int compat_tcp_setsockopt(struct sock
*sk
, int level
, int optname
,
402 char __user
*optval
, unsigned int optlen
);
403 void tcp_set_keepalive(struct sock
*sk
, int val
);
404 void tcp_syn_ack_timeout(const struct request_sock
*req
);
405 int tcp_recvmsg(struct sock
*sk
, struct msghdr
*msg
, size_t len
, int nonblock
,
406 int flags
, int *addr_len
);
407 void tcp_parse_options(const struct net
*net
, const struct sk_buff
*skb
,
408 struct tcp_options_received
*opt_rx
,
409 int estab
, struct tcp_fastopen_cookie
*foc
);
410 const u8
*tcp_parse_md5sig_option(const struct tcphdr
*th
);
413 * TCP v4 functions exported for the inet6 API
416 void tcp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
);
417 void tcp_v4_mtu_reduced(struct sock
*sk
);
418 void tcp_req_err(struct sock
*sk
, u32 seq
, bool abort
);
419 int tcp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
);
420 struct sock
*tcp_create_openreq_child(const struct sock
*sk
,
421 struct request_sock
*req
,
422 struct sk_buff
*skb
);
423 void tcp_ca_openreq_child(struct sock
*sk
, const struct dst_entry
*dst
);
424 struct sock
*tcp_v4_syn_recv_sock(const struct sock
*sk
, struct sk_buff
*skb
,
425 struct request_sock
*req
,
426 struct dst_entry
*dst
,
427 struct request_sock
*req_unhash
,
429 int tcp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
);
430 int tcp_v4_connect(struct sock
*sk
, struct sockaddr
*uaddr
, int addr_len
);
431 int tcp_connect(struct sock
*sk
);
432 enum tcp_synack_type
{
437 struct sk_buff
*tcp_make_synack(const struct sock
*sk
, struct dst_entry
*dst
,
438 struct request_sock
*req
,
439 struct tcp_fastopen_cookie
*foc
,
440 enum tcp_synack_type synack_type
);
441 int tcp_disconnect(struct sock
*sk
, int flags
);
443 void tcp_finish_connect(struct sock
*sk
, struct sk_buff
*skb
);
444 int tcp_send_rcvq(struct sock
*sk
, struct msghdr
*msg
, size_t size
);
445 void inet_sk_rx_dst_set(struct sock
*sk
, const struct sk_buff
*skb
);
447 /* From syncookies.c */
448 struct sock
*tcp_get_cookie_sock(struct sock
*sk
, struct sk_buff
*skb
,
449 struct request_sock
*req
,
450 struct dst_entry
*dst
, u32 tsoff
);
451 int __cookie_v4_check(const struct iphdr
*iph
, const struct tcphdr
*th
,
453 struct sock
*cookie_v4_check(struct sock
*sk
, struct sk_buff
*skb
);
454 #ifdef CONFIG_SYN_COOKIES
456 /* Syncookies use a monotonic timer which increments every 60 seconds.
457 * This counter is used both as a hash input and partially encoded into
458 * the cookie value. A cookie is only validated further if the delta
459 * between the current counter value and the encoded one is less than this,
460 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if
461 * the counter advances immediately after a cookie is generated).
463 #define MAX_SYNCOOKIE_AGE 2
464 #define TCP_SYNCOOKIE_PERIOD (60 * HZ)
465 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD)
467 /* syncookies: remember time of last synqueue overflow
468 * But do not dirty this field too often (once per second is enough)
469 * It is racy as we do not hold a lock, but race is very minor.
471 static inline void tcp_synq_overflow(const struct sock
*sk
)
473 unsigned long last_overflow
= tcp_sk(sk
)->rx_opt
.ts_recent_stamp
;
474 unsigned long now
= jiffies
;
476 if (time_after(now
, last_overflow
+ HZ
))
477 tcp_sk(sk
)->rx_opt
.ts_recent_stamp
= now
;
480 /* syncookies: no recent synqueue overflow on this listening socket? */
481 static inline bool tcp_synq_no_recent_overflow(const struct sock
*sk
)
483 unsigned long last_overflow
= tcp_sk(sk
)->rx_opt
.ts_recent_stamp
;
485 return time_after(jiffies
, last_overflow
+ TCP_SYNCOOKIE_VALID
);
488 static inline u32
tcp_cookie_time(void)
490 u64 val
= get_jiffies_64();
492 do_div(val
, TCP_SYNCOOKIE_PERIOD
);
496 u32
__cookie_v4_init_sequence(const struct iphdr
*iph
, const struct tcphdr
*th
,
498 __u32
cookie_v4_init_sequence(const struct sk_buff
*skb
, __u16
*mss
);
499 u64
cookie_init_timestamp(struct request_sock
*req
);
500 bool cookie_timestamp_decode(const struct net
*net
,
501 struct tcp_options_received
*opt
);
502 bool cookie_ecn_ok(const struct tcp_options_received
*opt
,
503 const struct net
*net
, const struct dst_entry
*dst
);
505 /* From net/ipv6/syncookies.c */
506 int __cookie_v6_check(const struct ipv6hdr
*iph
, const struct tcphdr
*th
,
508 struct sock
*cookie_v6_check(struct sock
*sk
, struct sk_buff
*skb
);
510 u32
__cookie_v6_init_sequence(const struct ipv6hdr
*iph
,
511 const struct tcphdr
*th
, u16
*mssp
);
512 __u32
cookie_v6_init_sequence(const struct sk_buff
*skb
, __u16
*mss
);
516 u32
tcp_tso_autosize(const struct sock
*sk
, unsigned int mss_now
,
518 void __tcp_push_pending_frames(struct sock
*sk
, unsigned int cur_mss
,
520 int __tcp_retransmit_skb(struct sock
*sk
, struct sk_buff
*skb
, int segs
);
521 int tcp_retransmit_skb(struct sock
*sk
, struct sk_buff
*skb
, int segs
);
522 void tcp_retransmit_timer(struct sock
*sk
);
523 void tcp_xmit_retransmit_queue(struct sock
*);
524 void tcp_simple_retransmit(struct sock
*);
525 void tcp_enter_recovery(struct sock
*sk
, bool ece_ack
);
526 int tcp_trim_head(struct sock
*, struct sk_buff
*, u32
);
528 TCP_FRAG_IN_WRITE_QUEUE
,
529 TCP_FRAG_IN_RTX_QUEUE
,
531 int tcp_fragment(struct sock
*sk
, enum tcp_queue tcp_queue
,
532 struct sk_buff
*skb
, u32 len
,
533 unsigned int mss_now
, gfp_t gfp
);
535 void tcp_send_probe0(struct sock
*);
536 void tcp_send_partial(struct sock
*);
537 int tcp_write_wakeup(struct sock
*, int mib
);
538 void tcp_send_fin(struct sock
*sk
);
539 void tcp_send_active_reset(struct sock
*sk
, gfp_t priority
);
540 int tcp_send_synack(struct sock
*);
541 void tcp_push_one(struct sock
*, unsigned int mss_now
);
542 void __tcp_send_ack(struct sock
*sk
, u32 rcv_nxt
);
543 void tcp_send_ack(struct sock
*sk
);
544 void tcp_send_delayed_ack(struct sock
*sk
);
545 void tcp_send_loss_probe(struct sock
*sk
);
546 bool tcp_schedule_loss_probe(struct sock
*sk
, bool advancing_rto
);
547 void tcp_skb_collapse_tstamp(struct sk_buff
*skb
,
548 const struct sk_buff
*next_skb
);
551 void tcp_rearm_rto(struct sock
*sk
);
552 void tcp_synack_rtt_meas(struct sock
*sk
, struct request_sock
*req
);
553 void tcp_reset(struct sock
*sk
);
554 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock
*tp
, struct sk_buff
*skb
);
555 void tcp_fin(struct sock
*sk
);
558 void tcp_init_xmit_timers(struct sock
*);
559 static inline void tcp_clear_xmit_timers(struct sock
*sk
)
561 hrtimer_cancel(&tcp_sk(sk
)->pacing_timer
);
562 inet_csk_clear_xmit_timers(sk
);
565 unsigned int tcp_sync_mss(struct sock
*sk
, u32 pmtu
);
566 unsigned int tcp_current_mss(struct sock
*sk
);
568 /* Bound MSS / TSO packet size with the half of the window */
569 static inline int tcp_bound_to_half_wnd(struct tcp_sock
*tp
, int pktsize
)
573 /* When peer uses tiny windows, there is no use in packetizing
574 * to sub-MSS pieces for the sake of SWS or making sure there
575 * are enough packets in the pipe for fast recovery.
577 * On the other hand, for extremely large MSS devices, handling
578 * smaller than MSS windows in this way does make sense.
580 if (tp
->max_window
> TCP_MSS_DEFAULT
)
581 cutoff
= (tp
->max_window
>> 1);
583 cutoff
= tp
->max_window
;
585 if (cutoff
&& pktsize
> cutoff
)
586 return max_t(int, cutoff
, 68U - tp
->tcp_header_len
);
592 void tcp_get_info(struct sock
*, struct tcp_info
*);
594 /* Read 'sendfile()'-style from a TCP socket */
595 int tcp_read_sock(struct sock
*sk
, read_descriptor_t
*desc
,
596 sk_read_actor_t recv_actor
);
598 void tcp_initialize_rcv_mss(struct sock
*sk
);
600 int tcp_mtu_to_mss(struct sock
*sk
, int pmtu
);
601 int tcp_mss_to_mtu(struct sock
*sk
, int mss
);
602 void tcp_mtup_init(struct sock
*sk
);
603 void tcp_init_buffer_space(struct sock
*sk
);
605 static inline void tcp_bound_rto(const struct sock
*sk
)
607 if (inet_csk(sk
)->icsk_rto
> TCP_RTO_MAX
)
608 inet_csk(sk
)->icsk_rto
= TCP_RTO_MAX
;
611 static inline u32
__tcp_set_rto(const struct tcp_sock
*tp
)
613 return usecs_to_jiffies((tp
->srtt_us
>> 3) + tp
->rttvar_us
);
616 static inline void __tcp_fast_path_on(struct tcp_sock
*tp
, u32 snd_wnd
)
618 tp
->pred_flags
= htonl((tp
->tcp_header_len
<< 26) |
619 ntohl(TCP_FLAG_ACK
) |
623 static inline void tcp_fast_path_on(struct tcp_sock
*tp
)
625 __tcp_fast_path_on(tp
, tp
->snd_wnd
>> tp
->rx_opt
.snd_wscale
);
628 static inline void tcp_fast_path_check(struct sock
*sk
)
630 struct tcp_sock
*tp
= tcp_sk(sk
);
632 if (RB_EMPTY_ROOT(&tp
->out_of_order_queue
) &&
634 atomic_read(&sk
->sk_rmem_alloc
) < sk
->sk_rcvbuf
&&
636 tcp_fast_path_on(tp
);
639 /* Compute the actual rto_min value */
640 static inline u32
tcp_rto_min(struct sock
*sk
)
642 const struct dst_entry
*dst
= __sk_dst_get(sk
);
643 u32 rto_min
= TCP_RTO_MIN
;
645 if (dst
&& dst_metric_locked(dst
, RTAX_RTO_MIN
))
646 rto_min
= dst_metric_rtt(dst
, RTAX_RTO_MIN
);
650 static inline u32
tcp_rto_min_us(struct sock
*sk
)
652 return jiffies_to_usecs(tcp_rto_min(sk
));
655 static inline bool tcp_ca_dst_locked(const struct dst_entry
*dst
)
657 return dst_metric_locked(dst
, RTAX_CC_ALGO
);
660 /* Minimum RTT in usec. ~0 means not available. */
661 static inline u32
tcp_min_rtt(const struct tcp_sock
*tp
)
663 return minmax_get(&tp
->rtt_min
);
666 /* Compute the actual receive window we are currently advertising.
667 * Rcv_nxt can be after the window if our peer push more data
668 * than the offered window.
670 static inline u32
tcp_receive_window(const struct tcp_sock
*tp
)
672 s32 win
= tp
->rcv_wup
+ tp
->rcv_wnd
- tp
->rcv_nxt
;
679 /* Choose a new window, without checks for shrinking, and without
680 * scaling applied to the result. The caller does these things
681 * if necessary. This is a "raw" window selection.
683 u32
__tcp_select_window(struct sock
*sk
);
685 void tcp_send_window_probe(struct sock
*sk
);
687 /* TCP uses 32bit jiffies to save some space.
688 * Note that this is different from tcp_time_stamp, which
689 * historically has been the same until linux-4.13.
691 #define tcp_jiffies32 ((u32)jiffies)
694 * Deliver a 32bit value for TCP timestamp option (RFC 7323)
695 * It is no longer tied to jiffies, but to 1 ms clock.
696 * Note: double check if you want to use tcp_jiffies32 instead of this.
698 #define TCP_TS_HZ 1000
700 static inline u64
tcp_clock_ns(void)
702 return local_clock();
705 static inline u64
tcp_clock_us(void)
707 return div_u64(tcp_clock_ns(), NSEC_PER_USEC
);
710 /* This should only be used in contexts where tp->tcp_mstamp is up to date */
711 static inline u32
tcp_time_stamp(const struct tcp_sock
*tp
)
713 return div_u64(tp
->tcp_mstamp
, USEC_PER_SEC
/ TCP_TS_HZ
);
716 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */
717 static inline u32
tcp_time_stamp_raw(void)
719 return div_u64(tcp_clock_ns(), NSEC_PER_SEC
/ TCP_TS_HZ
);
723 /* Refresh 1us clock of a TCP socket,
724 * ensuring monotically increasing values.
726 static inline void tcp_mstamp_refresh(struct tcp_sock
*tp
)
728 u64 val
= tcp_clock_us();
730 if (val
> tp
->tcp_mstamp
)
731 tp
->tcp_mstamp
= val
;
734 static inline u32
tcp_stamp_us_delta(u64 t1
, u64 t0
)
736 return max_t(s64
, t1
- t0
, 0);
739 static inline u32
tcp_skb_timestamp(const struct sk_buff
*skb
)
741 return div_u64(skb
->skb_mstamp
, USEC_PER_SEC
/ TCP_TS_HZ
);
745 #define tcp_flag_byte(th) (((u_int8_t *)th)[13])
747 #define TCPHDR_FIN 0x01
748 #define TCPHDR_SYN 0x02
749 #define TCPHDR_RST 0x04
750 #define TCPHDR_PSH 0x08
751 #define TCPHDR_ACK 0x10
752 #define TCPHDR_URG 0x20
753 #define TCPHDR_ECE 0x40
754 #define TCPHDR_CWR 0x80
756 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR)
758 /* This is what the send packet queuing engine uses to pass
759 * TCP per-packet control information to the transmission code.
760 * We also store the host-order sequence numbers in here too.
761 * This is 44 bytes if IPV6 is enabled.
762 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
765 __u32 seq
; /* Starting sequence number */
766 __u32 end_seq
; /* SEQ + FIN + SYN + datalen */
768 /* Note : tcp_tw_isn is used in input path only
769 * (isn chosen by tcp_timewait_state_process())
771 * tcp_gso_segs/size are used in write queue only,
772 * cf tcp_skb_pcount()/tcp_skb_mss()
780 __u8 tcp_flags
; /* TCP header flags. (tcp[13]) */
782 __u8 sacked
; /* State flags for SACK. */
783 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
784 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
785 #define TCPCB_LOST 0x04 /* SKB is lost */
786 #define TCPCB_TAGBITS 0x07 /* All tag bits */
787 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */
788 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
789 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
792 __u8 ip_dsfield
; /* IPv4 tos or IPv6 dsfield */
793 __u8 txstamp_ack
:1, /* Record TX timestamp for ack? */
794 eor
:1, /* Is skb MSG_EOR marked? */
795 has_rxtstamp
:1, /* SKB has a RX timestamp */
797 __u32 ack_seq
; /* Sequence number ACK'd */
800 /* There is space for up to 24 bytes */
801 __u32 in_flight
:30,/* Bytes in flight at transmit */
802 is_app_limited
:1, /* cwnd not fully used? */
804 /* pkts S/ACKed so far upon tx of skb, incl retrans: */
806 /* start of send pipeline phase */
808 /* when we reached the "delivered" count */
809 u64 delivered_mstamp
;
810 } tx
; /* only used for outgoing skbs */
812 struct inet_skb_parm h4
;
813 #if IS_ENABLED(CONFIG_IPV6)
814 struct inet6_skb_parm h6
;
816 } header
; /* For incoming skbs */
826 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
829 #if IS_ENABLED(CONFIG_IPV6)
830 /* This is the variant of inet6_iif() that must be used by TCP,
831 * as TCP moves IP6CB into a different location in skb->cb[]
833 static inline int tcp_v6_iif(const struct sk_buff
*skb
)
835 return TCP_SKB_CB(skb
)->header
.h6
.iif
;
838 static inline int tcp_v6_iif_l3_slave(const struct sk_buff
*skb
)
840 bool l3_slave
= ipv6_l3mdev_skb(TCP_SKB_CB(skb
)->header
.h6
.flags
);
842 return l3_slave
? skb
->skb_iif
: TCP_SKB_CB(skb
)->header
.h6
.iif
;
845 /* TCP_SKB_CB reference means this can not be used from early demux */
846 static inline int tcp_v6_sdif(const struct sk_buff
*skb
)
848 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
849 if (skb
&& ipv6_l3mdev_skb(TCP_SKB_CB(skb
)->header
.h6
.flags
))
850 return TCP_SKB_CB(skb
)->header
.h6
.iif
;
856 static inline bool inet_exact_dif_match(struct net
*net
, struct sk_buff
*skb
)
858 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
859 if (!net
->ipv4
.sysctl_tcp_l3mdev_accept
&&
860 skb
&& ipv4_l3mdev_skb(IPCB(skb
)->flags
))
866 /* TCP_SKB_CB reference means this can not be used from early demux */
867 static inline int tcp_v4_sdif(struct sk_buff
*skb
)
869 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
870 if (skb
&& ipv4_l3mdev_skb(TCP_SKB_CB(skb
)->header
.h4
.flags
))
871 return TCP_SKB_CB(skb
)->header
.h4
.iif
;
876 /* Due to TSO, an SKB can be composed of multiple actual
877 * packets. To keep these tracked properly, we use this.
879 static inline int tcp_skb_pcount(const struct sk_buff
*skb
)
881 return TCP_SKB_CB(skb
)->tcp_gso_segs
;
884 static inline void tcp_skb_pcount_set(struct sk_buff
*skb
, int segs
)
886 TCP_SKB_CB(skb
)->tcp_gso_segs
= segs
;
889 static inline void tcp_skb_pcount_add(struct sk_buff
*skb
, int segs
)
891 TCP_SKB_CB(skb
)->tcp_gso_segs
+= segs
;
894 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
895 static inline int tcp_skb_mss(const struct sk_buff
*skb
)
897 return TCP_SKB_CB(skb
)->tcp_gso_size
;
900 static inline bool tcp_skb_can_collapse_to(const struct sk_buff
*skb
)
902 return likely(!TCP_SKB_CB(skb
)->eor
);
905 /* Events passed to congestion control interface */
907 CA_EVENT_TX_START
, /* first transmit when no packets in flight */
908 CA_EVENT_CWND_RESTART
, /* congestion window restart */
909 CA_EVENT_COMPLETE_CWR
, /* end of congestion recovery */
910 CA_EVENT_LOSS
, /* loss timeout */
911 CA_EVENT_ECN_NO_CE
, /* ECT set, but not CE marked */
912 CA_EVENT_ECN_IS_CE
, /* received CE marked IP packet */
915 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */
916 enum tcp_ca_ack_event_flags
{
917 CA_ACK_SLOWPATH
= (1 << 0), /* In slow path processing */
918 CA_ACK_WIN_UPDATE
= (1 << 1), /* ACK updated window */
919 CA_ACK_ECE
= (1 << 2), /* ECE bit is set on ack */
923 * Interface for adding new TCP congestion control handlers
925 #define TCP_CA_NAME_MAX 16
926 #define TCP_CA_MAX 128
927 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
929 #define TCP_CA_UNSPEC 0
931 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */
932 #define TCP_CONG_NON_RESTRICTED 0x1
933 /* Requires ECN/ECT set on all packets */
934 #define TCP_CONG_NEEDS_ECN 0x2
944 /* A rate sample measures the number of (original/retransmitted) data
945 * packets delivered "delivered" over an interval of time "interval_us".
946 * The tcp_rate.c code fills in the rate sample, and congestion
947 * control modules that define a cong_control function to run at the end
948 * of ACK processing can optionally chose to consult this sample when
949 * setting cwnd and pacing rate.
950 * A sample is invalid if "delivered" or "interval_us" is negative.
953 u64 prior_mstamp
; /* starting timestamp for interval */
954 u32 prior_delivered
; /* tp->delivered at "prior_mstamp" */
955 s32 delivered
; /* number of packets delivered over interval */
956 long interval_us
; /* time for tp->delivered to incr "delivered" */
957 long rtt_us
; /* RTT of last (S)ACKed packet (or -1) */
958 int losses
; /* number of packets marked lost upon ACK */
959 u32 acked_sacked
; /* number of packets newly (S)ACKed upon ACK */
960 u32 prior_in_flight
; /* in flight before this ACK */
961 bool is_app_limited
; /* is sample from packet with bubble in pipe? */
962 bool is_retrans
; /* is sample from retransmission? */
965 struct tcp_congestion_ops
{
966 struct list_head list
;
970 /* initialize private data (optional) */
971 void (*init
)(struct sock
*sk
);
972 /* cleanup private data (optional) */
973 void (*release
)(struct sock
*sk
);
975 /* return slow start threshold (required) */
976 u32 (*ssthresh
)(struct sock
*sk
);
977 /* do new cwnd calculation (required) */
978 void (*cong_avoid
)(struct sock
*sk
, u32 ack
, u32 acked
);
979 /* call before changing ca_state (optional) */
980 void (*set_state
)(struct sock
*sk
, u8 new_state
);
981 /* call when cwnd event occurs (optional) */
982 void (*cwnd_event
)(struct sock
*sk
, enum tcp_ca_event ev
);
983 /* call when ack arrives (optional) */
984 void (*in_ack_event
)(struct sock
*sk
, u32 flags
);
985 /* new value of cwnd after loss (required) */
986 u32 (*undo_cwnd
)(struct sock
*sk
);
987 /* hook for packet ack accounting (optional) */
988 void (*pkts_acked
)(struct sock
*sk
, const struct ack_sample
*sample
);
989 /* suggest number of segments for each skb to transmit (optional) */
990 u32 (*tso_segs_goal
)(struct sock
*sk
);
991 /* returns the multiplier used in tcp_sndbuf_expand (optional) */
992 u32 (*sndbuf_expand
)(struct sock
*sk
);
993 /* call when packets are delivered to update cwnd and pacing rate,
994 * after all the ca_state processing. (optional)
996 void (*cong_control
)(struct sock
*sk
, const struct rate_sample
*rs
);
997 /* get info for inet_diag (optional) */
998 size_t (*get_info
)(struct sock
*sk
, u32 ext
, int *attr
,
999 union tcp_cc_info
*info
);
1001 char name
[TCP_CA_NAME_MAX
];
1002 struct module
*owner
;
1005 int tcp_register_congestion_control(struct tcp_congestion_ops
*type
);
1006 void tcp_unregister_congestion_control(struct tcp_congestion_ops
*type
);
1008 void tcp_assign_congestion_control(struct sock
*sk
);
1009 void tcp_init_congestion_control(struct sock
*sk
);
1010 void tcp_cleanup_congestion_control(struct sock
*sk
);
1011 int tcp_set_default_congestion_control(struct net
*net
, const char *name
);
1012 void tcp_get_default_congestion_control(struct net
*net
, char *name
);
1013 void tcp_get_available_congestion_control(char *buf
, size_t len
);
1014 void tcp_get_allowed_congestion_control(char *buf
, size_t len
);
1015 int tcp_set_allowed_congestion_control(char *allowed
);
1016 int tcp_set_congestion_control(struct sock
*sk
, const char *name
, bool load
,
1017 bool reinit
, bool cap_net_admin
);
1018 u32
tcp_slow_start(struct tcp_sock
*tp
, u32 acked
);
1019 void tcp_cong_avoid_ai(struct tcp_sock
*tp
, u32 w
, u32 acked
);
1021 u32
tcp_reno_ssthresh(struct sock
*sk
);
1022 u32
tcp_reno_undo_cwnd(struct sock
*sk
);
1023 void tcp_reno_cong_avoid(struct sock
*sk
, u32 ack
, u32 acked
);
1024 extern struct tcp_congestion_ops tcp_reno
;
1026 struct tcp_congestion_ops
*tcp_ca_find_key(u32 key
);
1027 u32
tcp_ca_get_key_by_name(struct net
*net
, const char *name
, bool *ecn_ca
);
1029 char *tcp_ca_get_name_by_key(u32 key
, char *buffer
);
1031 static inline char *tcp_ca_get_name_by_key(u32 key
, char *buffer
)
1037 static inline bool tcp_ca_needs_ecn(const struct sock
*sk
)
1039 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
1041 return icsk
->icsk_ca_ops
->flags
& TCP_CONG_NEEDS_ECN
;
1044 static inline void tcp_set_ca_state(struct sock
*sk
, const u8 ca_state
)
1046 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1048 if (icsk
->icsk_ca_ops
->set_state
)
1049 icsk
->icsk_ca_ops
->set_state(sk
, ca_state
);
1050 icsk
->icsk_ca_state
= ca_state
;
1053 static inline void tcp_ca_event(struct sock
*sk
, const enum tcp_ca_event event
)
1055 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
1057 if (icsk
->icsk_ca_ops
->cwnd_event
)
1058 icsk
->icsk_ca_ops
->cwnd_event(sk
, event
);
1061 /* From tcp_rate.c */
1062 void tcp_rate_skb_sent(struct sock
*sk
, struct sk_buff
*skb
);
1063 void tcp_rate_skb_delivered(struct sock
*sk
, struct sk_buff
*skb
,
1064 struct rate_sample
*rs
);
1065 void tcp_rate_gen(struct sock
*sk
, u32 delivered
, u32 lost
,
1066 bool is_sack_reneg
, struct rate_sample
*rs
);
1067 void tcp_rate_check_app_limited(struct sock
*sk
);
1069 /* These functions determine how the current flow behaves in respect of SACK
1070 * handling. SACK is negotiated with the peer, and therefore it can vary
1071 * between different flows.
1073 * tcp_is_sack - SACK enabled
1074 * tcp_is_reno - No SACK
1076 static inline int tcp_is_sack(const struct tcp_sock
*tp
)
1078 return tp
->rx_opt
.sack_ok
;
1081 static inline bool tcp_is_reno(const struct tcp_sock
*tp
)
1083 return !tcp_is_sack(tp
);
1086 static inline unsigned int tcp_left_out(const struct tcp_sock
*tp
)
1088 return tp
->sacked_out
+ tp
->lost_out
;
1091 /* This determines how many packets are "in the network" to the best
1092 * of our knowledge. In many cases it is conservative, but where
1093 * detailed information is available from the receiver (via SACK
1094 * blocks etc.) we can make more aggressive calculations.
1096 * Use this for decisions involving congestion control, use just
1097 * tp->packets_out to determine if the send queue is empty or not.
1099 * Read this equation as:
1101 * "Packets sent once on transmission queue" MINUS
1102 * "Packets left network, but not honestly ACKed yet" PLUS
1103 * "Packets fast retransmitted"
1105 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock
*tp
)
1107 return tp
->packets_out
- tcp_left_out(tp
) + tp
->retrans_out
;
1110 #define TCP_INFINITE_SSTHRESH 0x7fffffff
1112 static inline bool tcp_in_slow_start(const struct tcp_sock
*tp
)
1114 return tp
->snd_cwnd
< tp
->snd_ssthresh
;
1117 static inline bool tcp_in_initial_slowstart(const struct tcp_sock
*tp
)
1119 return tp
->snd_ssthresh
>= TCP_INFINITE_SSTHRESH
;
1122 static inline bool tcp_in_cwnd_reduction(const struct sock
*sk
)
1124 return (TCPF_CA_CWR
| TCPF_CA_Recovery
) &
1125 (1 << inet_csk(sk
)->icsk_ca_state
);
1128 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
1129 * The exception is cwnd reduction phase, when cwnd is decreasing towards
1132 static inline __u32
tcp_current_ssthresh(const struct sock
*sk
)
1134 const struct tcp_sock
*tp
= tcp_sk(sk
);
1136 if (tcp_in_cwnd_reduction(sk
))
1137 return tp
->snd_ssthresh
;
1139 return max(tp
->snd_ssthresh
,
1140 ((tp
->snd_cwnd
>> 1) +
1141 (tp
->snd_cwnd
>> 2)));
1144 /* Use define here intentionally to get WARN_ON location shown at the caller */
1145 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
1147 void tcp_enter_cwr(struct sock
*sk
);
1148 __u32
tcp_init_cwnd(const struct tcp_sock
*tp
, const struct dst_entry
*dst
);
1150 /* The maximum number of MSS of available cwnd for which TSO defers
1151 * sending if not using sysctl_tcp_tso_win_divisor.
1153 static inline __u32
tcp_max_tso_deferred_mss(const struct tcp_sock
*tp
)
1158 /* Returns end sequence number of the receiver's advertised window */
1159 static inline u32
tcp_wnd_end(const struct tcp_sock
*tp
)
1161 return tp
->snd_una
+ tp
->snd_wnd
;
1164 /* We follow the spirit of RFC2861 to validate cwnd but implement a more
1165 * flexible approach. The RFC suggests cwnd should not be raised unless
1166 * it was fully used previously. And that's exactly what we do in
1167 * congestion avoidance mode. But in slow start we allow cwnd to grow
1168 * as long as the application has used half the cwnd.
1170 * cwnd is 10 (IW10), but application sends 9 frames.
1171 * We allow cwnd to reach 18 when all frames are ACKed.
1172 * This check is safe because it's as aggressive as slow start which already
1173 * risks 100% overshoot. The advantage is that we discourage application to
1174 * either send more filler packets or data to artificially blow up the cwnd
1175 * usage, and allow application-limited process to probe bw more aggressively.
1177 static inline bool tcp_is_cwnd_limited(const struct sock
*sk
)
1179 const struct tcp_sock
*tp
= tcp_sk(sk
);
1181 /* If in slow start, ensure cwnd grows to twice what was ACKed. */
1182 if (tcp_in_slow_start(tp
))
1183 return tp
->snd_cwnd
< 2 * tp
->max_packets_out
;
1185 return tp
->is_cwnd_limited
;
1188 /* Something is really bad, we could not queue an additional packet,
1189 * because qdisc is full or receiver sent a 0 window.
1190 * We do not want to add fuel to the fire, or abort too early,
1191 * so make sure the timer we arm now is at least 200ms in the future,
1192 * regardless of current icsk_rto value (as it could be ~2ms)
1194 static inline unsigned long tcp_probe0_base(const struct sock
*sk
)
1196 return max_t(unsigned long, inet_csk(sk
)->icsk_rto
, TCP_RTO_MIN
);
1199 /* Variant of inet_csk_rto_backoff() used for zero window probes */
1200 static inline unsigned long tcp_probe0_when(const struct sock
*sk
,
1201 unsigned long max_when
)
1203 u64 when
= (u64
)tcp_probe0_base(sk
) << inet_csk(sk
)->icsk_backoff
;
1205 return (unsigned long)min_t(u64
, when
, max_when
);
1208 static inline void tcp_check_probe_timer(struct sock
*sk
)
1210 if (!tcp_sk(sk
)->packets_out
&& !inet_csk(sk
)->icsk_pending
)
1211 inet_csk_reset_xmit_timer(sk
, ICSK_TIME_PROBE0
,
1212 tcp_probe0_base(sk
), TCP_RTO_MAX
);
1215 static inline void tcp_init_wl(struct tcp_sock
*tp
, u32 seq
)
1220 static inline void tcp_update_wl(struct tcp_sock
*tp
, u32 seq
)
1226 * Calculate(/check) TCP checksum
1228 static inline __sum16
tcp_v4_check(int len
, __be32 saddr
,
1229 __be32 daddr
, __wsum base
)
1231 return csum_tcpudp_magic(saddr
,daddr
,len
,IPPROTO_TCP
,base
);
1234 static inline __sum16
__tcp_checksum_complete(struct sk_buff
*skb
)
1236 return __skb_checksum_complete(skb
);
1239 static inline bool tcp_checksum_complete(struct sk_buff
*skb
)
1241 return !skb_csum_unnecessary(skb
) &&
1242 __tcp_checksum_complete(skb
);
1245 bool tcp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
);
1246 int tcp_filter(struct sock
*sk
, struct sk_buff
*skb
);
1251 static const char *statename
[]={
1252 "Unused","Established","Syn Sent","Syn Recv",
1253 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
1254 "Close Wait","Last ACK","Listen","Closing"
1257 void tcp_set_state(struct sock
*sk
, int state
);
1259 void tcp_done(struct sock
*sk
);
1261 int tcp_abort(struct sock
*sk
, int err
);
1263 static inline void tcp_sack_reset(struct tcp_options_received
*rx_opt
)
1266 rx_opt
->num_sacks
= 0;
1269 u32
tcp_default_init_rwnd(u32 mss
);
1270 void tcp_cwnd_restart(struct sock
*sk
, s32 delta
);
1272 static inline void tcp_slow_start_after_idle_check(struct sock
*sk
)
1274 const struct tcp_congestion_ops
*ca_ops
= inet_csk(sk
)->icsk_ca_ops
;
1275 struct tcp_sock
*tp
= tcp_sk(sk
);
1278 if (!sock_net(sk
)->ipv4
.sysctl_tcp_slow_start_after_idle
|| tp
->packets_out
||
1279 ca_ops
->cong_control
)
1281 delta
= tcp_jiffies32
- tp
->lsndtime
;
1282 if (delta
> inet_csk(sk
)->icsk_rto
)
1283 tcp_cwnd_restart(sk
, delta
);
1286 /* Determine a window scaling and initial window to offer. */
1287 void tcp_select_initial_window(const struct sock
*sk
, int __space
,
1288 __u32 mss
, __u32
*rcv_wnd
,
1289 __u32
*window_clamp
, int wscale_ok
,
1290 __u8
*rcv_wscale
, __u32 init_rcv_wnd
);
1292 static inline int tcp_win_from_space(const struct sock
*sk
, int space
)
1294 int tcp_adv_win_scale
= sock_net(sk
)->ipv4
.sysctl_tcp_adv_win_scale
;
1296 return tcp_adv_win_scale
<= 0 ?
1297 (space
>>(-tcp_adv_win_scale
)) :
1298 space
- (space
>>tcp_adv_win_scale
);
1301 /* Note: caller must be prepared to deal with negative returns */
1302 static inline int tcp_space(const struct sock
*sk
)
1304 return tcp_win_from_space(sk
, sk
->sk_rcvbuf
-
1305 atomic_read(&sk
->sk_rmem_alloc
));
1308 static inline int tcp_full_space(const struct sock
*sk
)
1310 return tcp_win_from_space(sk
, sk
->sk_rcvbuf
);
1313 extern void tcp_openreq_init_rwin(struct request_sock
*req
,
1314 const struct sock
*sk_listener
,
1315 const struct dst_entry
*dst
);
1317 void tcp_enter_memory_pressure(struct sock
*sk
);
1318 void tcp_leave_memory_pressure(struct sock
*sk
);
1320 static inline int keepalive_intvl_when(const struct tcp_sock
*tp
)
1322 struct net
*net
= sock_net((struct sock
*)tp
);
1324 return tp
->keepalive_intvl
? : net
->ipv4
.sysctl_tcp_keepalive_intvl
;
1327 static inline int keepalive_time_when(const struct tcp_sock
*tp
)
1329 struct net
*net
= sock_net((struct sock
*)tp
);
1331 return tp
->keepalive_time
? : net
->ipv4
.sysctl_tcp_keepalive_time
;
1334 static inline int keepalive_probes(const struct tcp_sock
*tp
)
1336 struct net
*net
= sock_net((struct sock
*)tp
);
1338 return tp
->keepalive_probes
? : net
->ipv4
.sysctl_tcp_keepalive_probes
;
1341 static inline u32
keepalive_time_elapsed(const struct tcp_sock
*tp
)
1343 const struct inet_connection_sock
*icsk
= &tp
->inet_conn
;
1345 return min_t(u32
, tcp_jiffies32
- icsk
->icsk_ack
.lrcvtime
,
1346 tcp_jiffies32
- tp
->rcv_tstamp
);
1349 static inline int tcp_fin_time(const struct sock
*sk
)
1351 int fin_timeout
= tcp_sk(sk
)->linger2
? : sock_net(sk
)->ipv4
.sysctl_tcp_fin_timeout
;
1352 const int rto
= inet_csk(sk
)->icsk_rto
;
1354 if (fin_timeout
< (rto
<< 2) - (rto
>> 1))
1355 fin_timeout
= (rto
<< 2) - (rto
>> 1);
1360 static inline bool tcp_paws_check(const struct tcp_options_received
*rx_opt
,
1363 if ((s32
)(rx_opt
->ts_recent
- rx_opt
->rcv_tsval
) <= paws_win
)
1365 if (unlikely(get_seconds() >= rx_opt
->ts_recent_stamp
+ TCP_PAWS_24DAYS
))
1368 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0,
1369 * then following tcp messages have valid values. Ignore 0 value,
1370 * or else 'negative' tsval might forbid us to accept their packets.
1372 if (!rx_opt
->ts_recent
)
1377 static inline bool tcp_paws_reject(const struct tcp_options_received
*rx_opt
,
1380 if (tcp_paws_check(rx_opt
, 0))
1383 /* RST segments are not recommended to carry timestamp,
1384 and, if they do, it is recommended to ignore PAWS because
1385 "their cleanup function should take precedence over timestamps."
1386 Certainly, it is mistake. It is necessary to understand the reasons
1387 of this constraint to relax it: if peer reboots, clock may go
1388 out-of-sync and half-open connections will not be reset.
1389 Actually, the problem would be not existing if all
1390 the implementations followed draft about maintaining clock
1391 via reboots. Linux-2.2 DOES NOT!
1393 However, we can relax time bounds for RST segments to MSL.
1395 if (rst
&& get_seconds() >= rx_opt
->ts_recent_stamp
+ TCP_PAWS_MSL
)
1400 bool tcp_oow_rate_limited(struct net
*net
, const struct sk_buff
*skb
,
1401 int mib_idx
, u32
*last_oow_ack_time
);
1403 static inline void tcp_mib_init(struct net
*net
)
1406 TCP_ADD_STATS(net
, TCP_MIB_RTOALGORITHM
, 1);
1407 TCP_ADD_STATS(net
, TCP_MIB_RTOMIN
, TCP_RTO_MIN
*1000/HZ
);
1408 TCP_ADD_STATS(net
, TCP_MIB_RTOMAX
, TCP_RTO_MAX
*1000/HZ
);
1409 TCP_ADD_STATS(net
, TCP_MIB_MAXCONN
, -1);
1413 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock
*tp
)
1415 tp
->lost_skb_hint
= NULL
;
1418 static inline void tcp_clear_all_retrans_hints(struct tcp_sock
*tp
)
1420 tcp_clear_retrans_hints_partial(tp
);
1421 tp
->retransmit_skb_hint
= NULL
;
1424 union tcp_md5_addr
{
1426 #if IS_ENABLED(CONFIG_IPV6)
1431 /* - key database */
1432 struct tcp_md5sig_key
{
1433 struct hlist_node node
;
1435 u8 family
; /* AF_INET or AF_INET6 */
1436 union tcp_md5_addr addr
;
1438 u8 key
[TCP_MD5SIG_MAXKEYLEN
];
1439 struct rcu_head rcu
;
1443 struct tcp_md5sig_info
{
1444 struct hlist_head head
;
1445 struct rcu_head rcu
;
1448 /* - pseudo header */
1449 struct tcp4_pseudohdr
{
1457 struct tcp6_pseudohdr
{
1458 struct in6_addr saddr
;
1459 struct in6_addr daddr
;
1461 __be32 protocol
; /* including padding */
1464 union tcp_md5sum_block
{
1465 struct tcp4_pseudohdr ip4
;
1466 #if IS_ENABLED(CONFIG_IPV6)
1467 struct tcp6_pseudohdr ip6
;
1471 /* - pool: digest algorithm, hash description and scratch buffer */
1472 struct tcp_md5sig_pool
{
1473 struct ahash_request
*md5_req
;
1478 int tcp_v4_md5_hash_skb(char *md5_hash
, const struct tcp_md5sig_key
*key
,
1479 const struct sock
*sk
, const struct sk_buff
*skb
);
1480 int tcp_md5_do_add(struct sock
*sk
, const union tcp_md5_addr
*addr
,
1481 int family
, u8 prefixlen
, const u8
*newkey
, u8 newkeylen
,
1483 int tcp_md5_do_del(struct sock
*sk
, const union tcp_md5_addr
*addr
,
1484 int family
, u8 prefixlen
);
1485 struct tcp_md5sig_key
*tcp_v4_md5_lookup(const struct sock
*sk
,
1486 const struct sock
*addr_sk
);
1488 #ifdef CONFIG_TCP_MD5SIG
1489 struct tcp_md5sig_key
*tcp_md5_do_lookup(const struct sock
*sk
,
1490 const union tcp_md5_addr
*addr
,
1492 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key)
1494 static inline struct tcp_md5sig_key
*tcp_md5_do_lookup(const struct sock
*sk
,
1495 const union tcp_md5_addr
*addr
,
1500 #define tcp_twsk_md5_key(twsk) NULL
1503 bool tcp_alloc_md5sig_pool(void);
1505 struct tcp_md5sig_pool
*tcp_get_md5sig_pool(void);
1506 static inline void tcp_put_md5sig_pool(void)
1511 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool
*, const struct sk_buff
*,
1512 unsigned int header_len
);
1513 int tcp_md5_hash_key(struct tcp_md5sig_pool
*hp
,
1514 const struct tcp_md5sig_key
*key
);
1516 /* From tcp_fastopen.c */
1517 void tcp_fastopen_cache_get(struct sock
*sk
, u16
*mss
,
1518 struct tcp_fastopen_cookie
*cookie
, int *syn_loss
,
1519 unsigned long *last_syn_loss
);
1520 void tcp_fastopen_cache_set(struct sock
*sk
, u16 mss
,
1521 struct tcp_fastopen_cookie
*cookie
, bool syn_lost
,
1523 struct tcp_fastopen_request
{
1524 /* Fast Open cookie. Size 0 means a cookie request */
1525 struct tcp_fastopen_cookie cookie
;
1526 struct msghdr
*data
; /* data in MSG_FASTOPEN */
1528 int copied
; /* queued in tcp_connect() */
1530 void tcp_free_fastopen_req(struct tcp_sock
*tp
);
1531 void tcp_fastopen_destroy_cipher(struct sock
*sk
);
1532 void tcp_fastopen_ctx_destroy(struct net
*net
);
1533 int tcp_fastopen_reset_cipher(struct net
*net
, struct sock
*sk
,
1534 void *key
, unsigned int len
);
1535 void tcp_fastopen_add_skb(struct sock
*sk
, struct sk_buff
*skb
);
1536 struct sock
*tcp_try_fastopen(struct sock
*sk
, struct sk_buff
*skb
,
1537 struct request_sock
*req
,
1538 struct tcp_fastopen_cookie
*foc
,
1539 const struct dst_entry
*dst
);
1540 void tcp_fastopen_init_key_once(struct net
*net
);
1541 bool tcp_fastopen_cookie_check(struct sock
*sk
, u16
*mss
,
1542 struct tcp_fastopen_cookie
*cookie
);
1543 bool tcp_fastopen_defer_connect(struct sock
*sk
, int *err
);
1544 #define TCP_FASTOPEN_KEY_LENGTH 16
1546 /* Fastopen key context */
1547 struct tcp_fastopen_context
{
1548 struct crypto_cipher
*tfm
;
1549 __u8 key
[TCP_FASTOPEN_KEY_LENGTH
];
1550 struct rcu_head rcu
;
1553 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout
;
1554 void tcp_fastopen_active_disable(struct sock
*sk
);
1555 bool tcp_fastopen_active_should_disable(struct sock
*sk
);
1556 void tcp_fastopen_active_disable_ofo_check(struct sock
*sk
);
1557 void tcp_fastopen_active_timeout_reset(void);
1559 /* Latencies incurred by various limits for a sender. They are
1560 * chronograph-like stats that are mutually exclusive.
1564 TCP_CHRONO_BUSY
, /* Actively sending data (non-empty write queue) */
1565 TCP_CHRONO_RWND_LIMITED
, /* Stalled by insufficient receive window */
1566 TCP_CHRONO_SNDBUF_LIMITED
, /* Stalled by insufficient send buffer */
1570 void tcp_chrono_start(struct sock
*sk
, const enum tcp_chrono type
);
1571 void tcp_chrono_stop(struct sock
*sk
, const enum tcp_chrono type
);
1573 /* This helper is needed, because skb->tcp_tsorted_anchor uses
1574 * the same memory storage than skb->destructor/_skb_refdst
1576 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff
*skb
)
1578 skb
->destructor
= NULL
;
1579 skb
->_skb_refdst
= 0UL;
1582 #define tcp_skb_tsorted_save(skb) { \
1583 unsigned long _save = skb->_skb_refdst; \
1584 skb->_skb_refdst = 0UL;
1586 #define tcp_skb_tsorted_restore(skb) \
1587 skb->_skb_refdst = _save; \
1590 void tcp_write_queue_purge(struct sock
*sk
);
1592 static inline struct sk_buff
*tcp_rtx_queue_head(const struct sock
*sk
)
1594 return skb_rb_first(&sk
->tcp_rtx_queue
);
1597 static inline struct sk_buff
*tcp_rtx_queue_tail(const struct sock
*sk
)
1599 return skb_rb_last(&sk
->tcp_rtx_queue
);
1602 static inline struct sk_buff
*tcp_write_queue_head(const struct sock
*sk
)
1604 return skb_peek(&sk
->sk_write_queue
);
1607 static inline struct sk_buff
*tcp_write_queue_tail(const struct sock
*sk
)
1609 return skb_peek_tail(&sk
->sk_write_queue
);
1612 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1613 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1615 static inline struct sk_buff
*tcp_send_head(const struct sock
*sk
)
1617 return skb_peek(&sk
->sk_write_queue
);
1620 static inline bool tcp_skb_is_last(const struct sock
*sk
,
1621 const struct sk_buff
*skb
)
1623 return skb_queue_is_last(&sk
->sk_write_queue
, skb
);
1626 static inline bool tcp_write_queue_empty(const struct sock
*sk
)
1628 return skb_queue_empty(&sk
->sk_write_queue
);
1631 static inline bool tcp_rtx_queue_empty(const struct sock
*sk
)
1633 return RB_EMPTY_ROOT(&sk
->tcp_rtx_queue
);
1636 static inline bool tcp_rtx_and_write_queues_empty(const struct sock
*sk
)
1638 return tcp_rtx_queue_empty(sk
) && tcp_write_queue_empty(sk
);
1641 static inline void tcp_check_send_head(struct sock
*sk
, struct sk_buff
*skb_unlinked
)
1643 if (tcp_write_queue_empty(sk
))
1644 tcp_chrono_stop(sk
, TCP_CHRONO_BUSY
);
1647 static inline void __tcp_add_write_queue_tail(struct sock
*sk
, struct sk_buff
*skb
)
1649 __skb_queue_tail(&sk
->sk_write_queue
, skb
);
1652 static inline void tcp_add_write_queue_tail(struct sock
*sk
, struct sk_buff
*skb
)
1654 __tcp_add_write_queue_tail(sk
, skb
);
1656 /* Queue it, remembering where we must start sending. */
1657 if (sk
->sk_write_queue
.next
== skb
)
1658 tcp_chrono_start(sk
, TCP_CHRONO_BUSY
);
1661 /* Insert new before skb on the write queue of sk. */
1662 static inline void tcp_insert_write_queue_before(struct sk_buff
*new,
1663 struct sk_buff
*skb
,
1666 __skb_queue_before(&sk
->sk_write_queue
, skb
, new);
1669 static inline void tcp_unlink_write_queue(struct sk_buff
*skb
, struct sock
*sk
)
1671 tcp_skb_tsorted_anchor_cleanup(skb
);
1672 __skb_unlink(skb
, &sk
->sk_write_queue
);
1675 void tcp_rbtree_insert(struct rb_root
*root
, struct sk_buff
*skb
);
1677 static inline void tcp_rtx_queue_unlink(struct sk_buff
*skb
, struct sock
*sk
)
1679 tcp_skb_tsorted_anchor_cleanup(skb
);
1680 rb_erase(&skb
->rbnode
, &sk
->tcp_rtx_queue
);
1683 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff
*skb
, struct sock
*sk
)
1685 list_del(&skb
->tcp_tsorted_anchor
);
1686 tcp_rtx_queue_unlink(skb
, sk
);
1687 sk_wmem_free_skb(sk
, skb
);
1690 static inline void tcp_push_pending_frames(struct sock
*sk
)
1692 if (tcp_send_head(sk
)) {
1693 struct tcp_sock
*tp
= tcp_sk(sk
);
1695 __tcp_push_pending_frames(sk
, tcp_current_mss(sk
), tp
->nonagle
);
1699 /* Start sequence of the skb just after the highest skb with SACKed
1700 * bit, valid only if sacked_out > 0 or when the caller has ensured
1701 * validity by itself.
1703 static inline u32
tcp_highest_sack_seq(struct tcp_sock
*tp
)
1705 if (!tp
->sacked_out
)
1708 if (tp
->highest_sack
== NULL
)
1711 return TCP_SKB_CB(tp
->highest_sack
)->seq
;
1714 static inline void tcp_advance_highest_sack(struct sock
*sk
, struct sk_buff
*skb
)
1716 tcp_sk(sk
)->highest_sack
= skb_rb_next(skb
);
1719 static inline struct sk_buff
*tcp_highest_sack(struct sock
*sk
)
1721 return tcp_sk(sk
)->highest_sack
;
1724 static inline void tcp_highest_sack_reset(struct sock
*sk
)
1726 tcp_sk(sk
)->highest_sack
= tcp_rtx_queue_head(sk
);
1729 /* Called when old skb is about to be deleted and replaced by new skb */
1730 static inline void tcp_highest_sack_replace(struct sock
*sk
,
1731 struct sk_buff
*old
,
1732 struct sk_buff
*new)
1734 if (old
== tcp_highest_sack(sk
))
1735 tcp_sk(sk
)->highest_sack
= new;
1738 /* This helper checks if socket has IP_TRANSPARENT set */
1739 static inline bool inet_sk_transparent(const struct sock
*sk
)
1741 switch (sk
->sk_state
) {
1743 return inet_twsk(sk
)->tw_transparent
;
1744 case TCP_NEW_SYN_RECV
:
1745 return inet_rsk(inet_reqsk(sk
))->no_srccheck
;
1747 return inet_sk(sk
)->transparent
;
1750 /* Determines whether this is a thin stream (which may suffer from
1751 * increased latency). Used to trigger latency-reducing mechanisms.
1753 static inline bool tcp_stream_is_thin(struct tcp_sock
*tp
)
1755 return tp
->packets_out
< 4 && !tcp_in_initial_slowstart(tp
);
1759 enum tcp_seq_states
{
1760 TCP_SEQ_STATE_LISTENING
,
1761 TCP_SEQ_STATE_ESTABLISHED
,
1764 int tcp_seq_open(struct inode
*inode
, struct file
*file
);
1766 struct tcp_seq_afinfo
{
1769 const struct file_operations
*seq_fops
;
1770 struct seq_operations seq_ops
;
1773 struct tcp_iter_state
{
1774 struct seq_net_private p
;
1776 enum tcp_seq_states state
;
1777 struct sock
*syn_wait_sk
;
1778 int bucket
, offset
, sbucket
, num
;
1782 int tcp_proc_register(struct net
*net
, struct tcp_seq_afinfo
*afinfo
);
1783 void tcp_proc_unregister(struct net
*net
, struct tcp_seq_afinfo
*afinfo
);
1785 extern struct request_sock_ops tcp_request_sock_ops
;
1786 extern struct request_sock_ops tcp6_request_sock_ops
;
1788 void tcp_v4_destroy_sock(struct sock
*sk
);
1790 struct sk_buff
*tcp_gso_segment(struct sk_buff
*skb
,
1791 netdev_features_t features
);
1792 struct sk_buff
**tcp_gro_receive(struct sk_buff
**head
, struct sk_buff
*skb
);
1793 int tcp_gro_complete(struct sk_buff
*skb
);
1795 void __tcp_v4_send_check(struct sk_buff
*skb
, __be32 saddr
, __be32 daddr
);
1797 static inline u32
tcp_notsent_lowat(const struct tcp_sock
*tp
)
1799 struct net
*net
= sock_net((struct sock
*)tp
);
1800 return tp
->notsent_lowat
?: net
->ipv4
.sysctl_tcp_notsent_lowat
;
1803 static inline bool tcp_stream_memory_free(const struct sock
*sk
)
1805 const struct tcp_sock
*tp
= tcp_sk(sk
);
1806 u32 notsent_bytes
= tp
->write_seq
- tp
->snd_nxt
;
1808 return notsent_bytes
< tcp_notsent_lowat(tp
);
1811 #ifdef CONFIG_PROC_FS
1812 int tcp4_proc_init(void);
1813 void tcp4_proc_exit(void);
1816 int tcp_rtx_synack(const struct sock
*sk
, struct request_sock
*req
);
1817 int tcp_conn_request(struct request_sock_ops
*rsk_ops
,
1818 const struct tcp_request_sock_ops
*af_ops
,
1819 struct sock
*sk
, struct sk_buff
*skb
);
1821 /* TCP af-specific functions */
1822 struct tcp_sock_af_ops
{
1823 #ifdef CONFIG_TCP_MD5SIG
1824 struct tcp_md5sig_key
*(*md5_lookup
) (const struct sock
*sk
,
1825 const struct sock
*addr_sk
);
1826 int (*calc_md5_hash
)(char *location
,
1827 const struct tcp_md5sig_key
*md5
,
1828 const struct sock
*sk
,
1829 const struct sk_buff
*skb
);
1830 int (*md5_parse
)(struct sock
*sk
,
1832 char __user
*optval
,
1837 struct tcp_request_sock_ops
{
1839 #ifdef CONFIG_TCP_MD5SIG
1840 struct tcp_md5sig_key
*(*req_md5_lookup
)(const struct sock
*sk
,
1841 const struct sock
*addr_sk
);
1842 int (*calc_md5_hash
) (char *location
,
1843 const struct tcp_md5sig_key
*md5
,
1844 const struct sock
*sk
,
1845 const struct sk_buff
*skb
);
1847 void (*init_req
)(struct request_sock
*req
,
1848 const struct sock
*sk_listener
,
1849 struct sk_buff
*skb
);
1850 #ifdef CONFIG_SYN_COOKIES
1851 __u32 (*cookie_init_seq
)(const struct sk_buff
*skb
,
1854 struct dst_entry
*(*route_req
)(const struct sock
*sk
, struct flowi
*fl
,
1855 const struct request_sock
*req
);
1856 u32 (*init_seq
)(const struct sk_buff
*skb
);
1857 u32 (*init_ts_off
)(const struct net
*net
, const struct sk_buff
*skb
);
1858 int (*send_synack
)(const struct sock
*sk
, struct dst_entry
*dst
,
1859 struct flowi
*fl
, struct request_sock
*req
,
1860 struct tcp_fastopen_cookie
*foc
,
1861 enum tcp_synack_type synack_type
);
1864 #ifdef CONFIG_SYN_COOKIES
1865 static inline __u32
cookie_init_sequence(const struct tcp_request_sock_ops
*ops
,
1866 const struct sock
*sk
, struct sk_buff
*skb
,
1869 tcp_synq_overflow(sk
);
1870 __NET_INC_STATS(sock_net(sk
), LINUX_MIB_SYNCOOKIESSENT
);
1871 return ops
->cookie_init_seq(skb
, mss
);
1874 static inline __u32
cookie_init_sequence(const struct tcp_request_sock_ops
*ops
,
1875 const struct sock
*sk
, struct sk_buff
*skb
,
1882 int tcpv4_offload_init(void);
1884 void tcp_v4_init(void);
1885 void tcp_init(void);
1887 /* tcp_recovery.c */
1888 extern void tcp_rack_mark_lost(struct sock
*sk
);
1889 extern void tcp_rack_advance(struct tcp_sock
*tp
, u8 sacked
, u32 end_seq
,
1891 extern void tcp_rack_reo_timeout(struct sock
*sk
);
1892 extern void tcp_rack_update_reo_wnd(struct sock
*sk
, struct rate_sample
*rs
);
1894 /* At how many usecs into the future should the RTO fire? */
1895 static inline s64
tcp_rto_delta_us(const struct sock
*sk
)
1897 const struct sk_buff
*skb
= tcp_rtx_queue_head(sk
);
1898 u32 rto
= inet_csk(sk
)->icsk_rto
;
1899 u64 rto_time_stamp_us
= skb
->skb_mstamp
+ jiffies_to_usecs(rto
);
1901 return rto_time_stamp_us
- tcp_sk(sk
)->tcp_mstamp
;
1905 * Save and compile IPv4 options, return a pointer to it
1907 static inline struct ip_options_rcu
*tcp_v4_save_options(struct net
*net
,
1908 struct sk_buff
*skb
)
1910 const struct ip_options
*opt
= &TCP_SKB_CB(skb
)->header
.h4
.opt
;
1911 struct ip_options_rcu
*dopt
= NULL
;
1914 int opt_size
= sizeof(*dopt
) + opt
->optlen
;
1916 dopt
= kmalloc(opt_size
, GFP_ATOMIC
);
1917 if (dopt
&& __ip_options_echo(net
, &dopt
->opt
, skb
, opt
)) {
1925 /* locally generated TCP pure ACKs have skb->truesize == 2
1926 * (check tcp_send_ack() in net/ipv4/tcp_output.c )
1927 * This is much faster than dissecting the packet to find out.
1928 * (Think of GRE encapsulations, IPv4, IPv6, ...)
1930 static inline bool skb_is_tcp_pure_ack(const struct sk_buff
*skb
)
1932 return skb
->truesize
== 2;
1935 static inline void skb_set_tcp_pure_ack(struct sk_buff
*skb
)
1940 static inline int tcp_inq(struct sock
*sk
)
1942 struct tcp_sock
*tp
= tcp_sk(sk
);
1945 if ((1 << sk
->sk_state
) & (TCPF_SYN_SENT
| TCPF_SYN_RECV
)) {
1947 } else if (sock_flag(sk
, SOCK_URGINLINE
) ||
1949 before(tp
->urg_seq
, tp
->copied_seq
) ||
1950 !before(tp
->urg_seq
, tp
->rcv_nxt
)) {
1952 answ
= tp
->rcv_nxt
- tp
->copied_seq
;
1954 /* Subtract 1, if FIN was received */
1955 if (answ
&& sock_flag(sk
, SOCK_DONE
))
1958 answ
= tp
->urg_seq
- tp
->copied_seq
;
1964 int tcp_peek_len(struct socket
*sock
);
1966 static inline void tcp_segs_in(struct tcp_sock
*tp
, const struct sk_buff
*skb
)
1970 segs_in
= max_t(u16
, 1, skb_shinfo(skb
)->gso_segs
);
1971 tp
->segs_in
+= segs_in
;
1972 if (skb
->len
> tcp_hdrlen(skb
))
1973 tp
->data_segs_in
+= segs_in
;
1977 * TCP listen path runs lockless.
1978 * We forced "struct sock" to be const qualified to make sure
1979 * we don't modify one of its field by mistake.
1980 * Here, we increment sk_drops which is an atomic_t, so we can safely
1981 * make sock writable again.
1983 static inline void tcp_listendrop(const struct sock
*sk
)
1985 atomic_inc(&((struct sock
*)sk
)->sk_drops
);
1986 __NET_INC_STATS(sock_net(sk
), LINUX_MIB_LISTENDROPS
);
1989 enum hrtimer_restart
tcp_pace_kick(struct hrtimer
*timer
);
1992 * Interface for adding Upper Level Protocols over TCP
1995 #define TCP_ULP_NAME_MAX 16
1996 #define TCP_ULP_MAX 128
1997 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX)
1999 struct tcp_ulp_ops
{
2000 struct list_head list
;
2002 /* initialize ulp */
2003 int (*init
)(struct sock
*sk
);
2005 void (*release
)(struct sock
*sk
);
2007 char name
[TCP_ULP_NAME_MAX
];
2008 struct module
*owner
;
2010 int tcp_register_ulp(struct tcp_ulp_ops
*type
);
2011 void tcp_unregister_ulp(struct tcp_ulp_ops
*type
);
2012 int tcp_set_ulp(struct sock
*sk
, const char *name
);
2013 void tcp_get_available_ulp(char *buf
, size_t len
);
2014 void tcp_cleanup_ulp(struct sock
*sk
);
2016 #define MODULE_ALIAS_TCP_ULP(name) \
2017 __MODULE_INFO(alias, alias_userspace, name); \
2018 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name)
2020 /* Call BPF_SOCK_OPS program that returns an int. If the return value
2021 * is < 0, then the BPF op failed (for example if the loaded BPF
2022 * program does not support the chosen operation or there is no BPF
2026 static inline int tcp_call_bpf(struct sock
*sk
, int op
)
2028 struct bpf_sock_ops_kern sock_ops
;
2031 if (sk_fullsock(sk
))
2032 sock_owned_by_me(sk
);
2034 memset(&sock_ops
, 0, sizeof(sock_ops
));
2038 ret
= BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops
);
2040 ret
= sock_ops
.reply
;
2046 static inline int tcp_call_bpf(struct sock
*sk
, int op
)
2052 static inline u32
tcp_timeout_init(struct sock
*sk
)
2056 timeout
= tcp_call_bpf(sk
, BPF_SOCK_OPS_TIMEOUT_INIT
);
2059 timeout
= TCP_TIMEOUT_INIT
;
2063 static inline u32
tcp_rwnd_init_bpf(struct sock
*sk
)
2067 rwnd
= tcp_call_bpf(sk
, BPF_SOCK_OPS_RWND_INIT
);
2074 static inline bool tcp_bpf_ca_needs_ecn(struct sock
*sk
)
2076 return (tcp_call_bpf(sk
, BPF_SOCK_OPS_NEEDS_ECN
) == 1);
2079 #if IS_ENABLED(CONFIG_SMC)
2080 extern struct static_key_false tcp_have_smc
;