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>
39 #include <net/sock_reuseport.h>
43 #include <net/tcp_states.h>
44 #include <net/inet_ecn.h>
47 #include <linux/seq_file.h>
48 #include <linux/memcontrol.h>
49 #include <linux/bpf-cgroup.h>
51 extern struct inet_hashinfo tcp_hashinfo
;
53 extern struct percpu_counter tcp_orphan_count
;
54 void tcp_time_wait(struct sock
*sk
, int state
, int timeo
);
56 #define MAX_TCP_HEADER (128 + MAX_HEADER)
57 #define MAX_TCP_OPTION_SPACE 40
58 #define TCP_MIN_SND_MSS 48
59 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
62 * Never offer a window over 32767 without using window scaling. Some
63 * poor stacks do signed 16bit maths!
65 #define MAX_TCP_WINDOW 32767U
67 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
68 #define TCP_MIN_MSS 88U
70 /* The least MTU to use for probing */
71 #define TCP_BASE_MSS 1024
73 /* probing interval, default to 10 minutes as per RFC4821 */
74 #define TCP_PROBE_INTERVAL 600
76 /* Specify interval when tcp mtu probing will stop */
77 #define TCP_PROBE_THRESHOLD 8
79 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
80 #define TCP_FASTRETRANS_THRESH 3
82 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
83 #define TCP_MAX_QUICKACKS 16U
85 /* Maximal number of window scale according to RFC1323 */
86 #define TCP_MAX_WSCALE 14U
89 #define TCP_URG_VALID 0x0100
90 #define TCP_URG_NOTYET 0x0200
91 #define TCP_URG_READ 0x0400
93 #define TCP_RETR1 3 /*
94 * This is how many retries it does before it
95 * tries to figure out if the gateway is
96 * down. Minimal RFC value is 3; it corresponds
97 * to ~3sec-8min depending on RTO.
100 #define TCP_RETR2 15 /*
101 * This should take at least
102 * 90 minutes to time out.
103 * RFC1122 says that the limit is 100 sec.
104 * 15 is ~13-30min depending on RTO.
107 #define TCP_SYN_RETRIES 6 /* This is how many retries are done
108 * when active opening a connection.
109 * RFC1122 says the minimum retry MUST
110 * be at least 180secs. Nevertheless
111 * this value is corresponding to
112 * 63secs of retransmission with the
113 * current initial RTO.
116 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done
117 * when passive opening a connection.
118 * This is corresponding to 31secs of
119 * retransmission with the current
123 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
124 * state, about 60 seconds */
125 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
126 /* BSD style FIN_WAIT2 deadlock breaker.
127 * It used to be 3min, new value is 60sec,
128 * to combine FIN-WAIT-2 timeout with
132 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
134 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
135 #define TCP_ATO_MIN ((unsigned)(HZ/25))
137 #define TCP_DELACK_MIN 4U
138 #define TCP_ATO_MIN 4U
140 #define TCP_RTO_MAX ((unsigned)(120*HZ))
141 #define TCP_RTO_MIN ((unsigned)(HZ/5))
142 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */
143 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */
144 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now
145 * used as a fallback RTO for the
146 * initial data transmission if no
147 * valid RTT sample has been acquired,
148 * most likely due to retrans in 3WHS.
151 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
152 * for local resources.
154 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
155 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
156 #define TCP_KEEPALIVE_INTVL (75*HZ)
158 #define MAX_TCP_KEEPIDLE 32767
159 #define MAX_TCP_KEEPINTVL 32767
160 #define MAX_TCP_KEEPCNT 127
161 #define MAX_TCP_SYNCNT 127
163 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
165 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
166 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
167 * after this time. It should be equal
168 * (or greater than) TCP_TIMEWAIT_LEN
169 * to provide reliability equal to one
170 * provided by timewait state.
172 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
173 * timestamps. It must be less than
174 * minimal timewait lifetime.
180 #define TCPOPT_NOP 1 /* Padding */
181 #define TCPOPT_EOL 0 /* End of options */
182 #define TCPOPT_MSS 2 /* Segment size negotiating */
183 #define TCPOPT_WINDOW 3 /* Window scaling */
184 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
185 #define TCPOPT_SACK 5 /* SACK Block */
186 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
187 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
188 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
189 #define TCPOPT_EXP 254 /* Experimental */
190 /* Magic number to be after the option value for sharing TCP
191 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
193 #define TCPOPT_FASTOPEN_MAGIC 0xF989
194 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9
200 #define TCPOLEN_MSS 4
201 #define TCPOLEN_WINDOW 3
202 #define TCPOLEN_SACK_PERM 2
203 #define TCPOLEN_TIMESTAMP 10
204 #define TCPOLEN_MD5SIG 18
205 #define TCPOLEN_FASTOPEN_BASE 2
206 #define TCPOLEN_EXP_FASTOPEN_BASE 4
207 #define TCPOLEN_EXP_SMC_BASE 6
209 /* But this is what stacks really send out. */
210 #define TCPOLEN_TSTAMP_ALIGNED 12
211 #define TCPOLEN_WSCALE_ALIGNED 4
212 #define TCPOLEN_SACKPERM_ALIGNED 4
213 #define TCPOLEN_SACK_BASE 2
214 #define TCPOLEN_SACK_BASE_ALIGNED 4
215 #define TCPOLEN_SACK_PERBLOCK 8
216 #define TCPOLEN_MD5SIG_ALIGNED 20
217 #define TCPOLEN_MSS_ALIGNED 4
218 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8
220 /* Flags in tp->nonagle */
221 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
222 #define TCP_NAGLE_CORK 2 /* Socket is corked */
223 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
225 /* TCP thin-stream limits */
226 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
228 /* TCP initial congestion window as per rfc6928 */
229 #define TCP_INIT_CWND 10
231 /* Bit Flags for sysctl_tcp_fastopen */
232 #define TFO_CLIENT_ENABLE 1
233 #define TFO_SERVER_ENABLE 2
234 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */
236 /* Accept SYN data w/o any cookie option */
237 #define TFO_SERVER_COOKIE_NOT_REQD 0x200
239 /* Force enable TFO on all listeners, i.e., not requiring the
240 * TCP_FASTOPEN socket option.
242 #define TFO_SERVER_WO_SOCKOPT1 0x400
245 /* sysctl variables for tcp */
246 extern int sysctl_tcp_max_orphans
;
247 extern long sysctl_tcp_mem
[3];
249 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */
250 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */
251 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */
253 extern atomic_long_t tcp_memory_allocated
;
254 extern struct percpu_counter tcp_sockets_allocated
;
255 extern unsigned long tcp_memory_pressure
;
257 /* optimized version of sk_under_memory_pressure() for TCP sockets */
258 static inline bool tcp_under_memory_pressure(const struct sock
*sk
)
260 if (mem_cgroup_sockets_enabled
&& sk
->sk_memcg
&&
261 mem_cgroup_under_socket_pressure(sk
->sk_memcg
))
264 return tcp_memory_pressure
;
267 * The next routines deal with comparing 32 bit unsigned ints
268 * and worry about wraparound (automatic with unsigned arithmetic).
271 static inline bool before(__u32 seq1
, __u32 seq2
)
273 return (__s32
)(seq1
-seq2
) < 0;
275 #define after(seq2, seq1) before(seq1, seq2)
277 /* is s2<=s1<=s3 ? */
278 static inline bool between(__u32 seq1
, __u32 seq2
, __u32 seq3
)
280 return seq3
- seq2
>= seq1
- seq2
;
283 static inline bool tcp_out_of_memory(struct sock
*sk
)
285 if (sk
->sk_wmem_queued
> SOCK_MIN_SNDBUF
&&
286 sk_memory_allocated(sk
) > sk_prot_mem_limits(sk
, 2))
291 void sk_forced_mem_schedule(struct sock
*sk
, int size
);
293 static inline bool tcp_too_many_orphans(struct sock
*sk
, int shift
)
295 struct percpu_counter
*ocp
= sk
->sk_prot
->orphan_count
;
296 int orphans
= percpu_counter_read_positive(ocp
);
298 if (orphans
<< shift
> sysctl_tcp_max_orphans
) {
299 orphans
= percpu_counter_sum_positive(ocp
);
300 if (orphans
<< shift
> sysctl_tcp_max_orphans
)
306 bool tcp_check_oom(struct sock
*sk
, int shift
);
309 extern struct proto tcp_prot
;
311 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
312 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field)
313 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
314 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
316 void tcp_tasklet_init(void);
318 int tcp_v4_err(struct sk_buff
*skb
, u32
);
320 void tcp_shutdown(struct sock
*sk
, int how
);
322 int tcp_v4_early_demux(struct sk_buff
*skb
);
323 int tcp_v4_rcv(struct sk_buff
*skb
);
325 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock
*tw
);
326 int tcp_sendmsg(struct sock
*sk
, struct msghdr
*msg
, size_t size
);
327 int tcp_sendmsg_locked(struct sock
*sk
, struct msghdr
*msg
, size_t size
);
328 int tcp_sendpage(struct sock
*sk
, struct page
*page
, int offset
, size_t size
,
330 int tcp_sendpage_locked(struct sock
*sk
, struct page
*page
, int offset
,
331 size_t size
, int flags
);
332 ssize_t
do_tcp_sendpages(struct sock
*sk
, struct page
*page
, int offset
,
333 size_t size
, int flags
);
334 void tcp_release_cb(struct sock
*sk
);
335 void tcp_wfree(struct sk_buff
*skb
);
336 void tcp_write_timer_handler(struct sock
*sk
);
337 void tcp_delack_timer_handler(struct sock
*sk
);
338 int tcp_ioctl(struct sock
*sk
, int cmd
, unsigned long arg
);
339 int tcp_rcv_state_process(struct sock
*sk
, struct sk_buff
*skb
);
340 void tcp_rcv_established(struct sock
*sk
, struct sk_buff
*skb
);
341 void tcp_rcv_space_adjust(struct sock
*sk
);
342 int tcp_twsk_unique(struct sock
*sk
, struct sock
*sktw
, void *twp
);
343 void tcp_twsk_destructor(struct sock
*sk
);
344 ssize_t
tcp_splice_read(struct socket
*sk
, loff_t
*ppos
,
345 struct pipe_inode_info
*pipe
, size_t len
,
348 void tcp_enter_quickack_mode(struct sock
*sk
, unsigned int max_quickacks
);
349 static inline void tcp_dec_quickack_mode(struct sock
*sk
,
350 const unsigned int pkts
)
352 struct inet_connection_sock
*icsk
= inet_csk(sk
);
354 if (icsk
->icsk_ack
.quick
) {
355 if (pkts
>= icsk
->icsk_ack
.quick
) {
356 icsk
->icsk_ack
.quick
= 0;
357 /* Leaving quickack mode we deflate ATO. */
358 icsk
->icsk_ack
.ato
= TCP_ATO_MIN
;
360 icsk
->icsk_ack
.quick
-= pkts
;
365 #define TCP_ECN_QUEUE_CWR 2
366 #define TCP_ECN_DEMAND_CWR 4
367 #define TCP_ECN_SEEN 8
377 enum tcp_tw_status
tcp_timewait_state_process(struct inet_timewait_sock
*tw
,
379 const struct tcphdr
*th
);
380 struct sock
*tcp_check_req(struct sock
*sk
, struct sk_buff
*skb
,
381 struct request_sock
*req
, bool fastopen
,
383 int tcp_child_process(struct sock
*parent
, struct sock
*child
,
384 struct sk_buff
*skb
);
385 void tcp_enter_loss(struct sock
*sk
);
386 void tcp_cwnd_reduction(struct sock
*sk
, int newly_acked_sacked
, int flag
);
387 void tcp_clear_retrans(struct tcp_sock
*tp
);
388 void tcp_update_metrics(struct sock
*sk
);
389 void tcp_init_metrics(struct sock
*sk
);
390 void tcp_metrics_init(void);
391 bool tcp_peer_is_proven(struct request_sock
*req
, struct dst_entry
*dst
);
392 void tcp_close(struct sock
*sk
, long timeout
);
393 void tcp_init_sock(struct sock
*sk
);
394 void tcp_init_transfer(struct sock
*sk
, int bpf_op
);
395 __poll_t
tcp_poll(struct file
*file
, struct socket
*sock
,
396 struct poll_table_struct
*wait
);
397 int tcp_getsockopt(struct sock
*sk
, int level
, int optname
,
398 char __user
*optval
, int __user
*optlen
);
399 int tcp_setsockopt(struct sock
*sk
, int level
, int optname
,
400 char __user
*optval
, unsigned int optlen
);
401 int compat_tcp_getsockopt(struct sock
*sk
, int level
, int optname
,
402 char __user
*optval
, int __user
*optlen
);
403 int compat_tcp_setsockopt(struct sock
*sk
, int level
, int optname
,
404 char __user
*optval
, unsigned int optlen
);
405 void tcp_set_keepalive(struct sock
*sk
, int val
);
406 void tcp_syn_ack_timeout(const struct request_sock
*req
);
407 int tcp_recvmsg(struct sock
*sk
, struct msghdr
*msg
, size_t len
, int nonblock
,
408 int flags
, int *addr_len
);
409 int tcp_set_rcvlowat(struct sock
*sk
, int val
);
410 void tcp_data_ready(struct sock
*sk
);
412 int tcp_mmap(struct file
*file
, struct socket
*sock
,
413 struct vm_area_struct
*vma
);
415 void tcp_parse_options(const struct net
*net
, const struct sk_buff
*skb
,
416 struct tcp_options_received
*opt_rx
,
417 int estab
, struct tcp_fastopen_cookie
*foc
);
418 const u8
*tcp_parse_md5sig_option(const struct tcphdr
*th
);
421 * TCP v4 functions exported for the inet6 API
424 void tcp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
);
425 void tcp_v4_mtu_reduced(struct sock
*sk
);
426 void tcp_req_err(struct sock
*sk
, u32 seq
, bool abort
);
427 int tcp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
);
428 struct sock
*tcp_create_openreq_child(const struct sock
*sk
,
429 struct request_sock
*req
,
430 struct sk_buff
*skb
);
431 void tcp_ca_openreq_child(struct sock
*sk
, const struct dst_entry
*dst
);
432 struct sock
*tcp_v4_syn_recv_sock(const struct sock
*sk
, struct sk_buff
*skb
,
433 struct request_sock
*req
,
434 struct dst_entry
*dst
,
435 struct request_sock
*req_unhash
,
437 int tcp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
);
438 int tcp_v4_connect(struct sock
*sk
, struct sockaddr
*uaddr
, int addr_len
);
439 int tcp_connect(struct sock
*sk
);
440 enum tcp_synack_type
{
445 struct sk_buff
*tcp_make_synack(const struct sock
*sk
, struct dst_entry
*dst
,
446 struct request_sock
*req
,
447 struct tcp_fastopen_cookie
*foc
,
448 enum tcp_synack_type synack_type
);
449 int tcp_disconnect(struct sock
*sk
, int flags
);
451 void tcp_finish_connect(struct sock
*sk
, struct sk_buff
*skb
);
452 int tcp_send_rcvq(struct sock
*sk
, struct msghdr
*msg
, size_t size
);
453 void inet_sk_rx_dst_set(struct sock
*sk
, const struct sk_buff
*skb
);
455 /* From syncookies.c */
456 struct sock
*tcp_get_cookie_sock(struct sock
*sk
, struct sk_buff
*skb
,
457 struct request_sock
*req
,
458 struct dst_entry
*dst
, u32 tsoff
);
459 int __cookie_v4_check(const struct iphdr
*iph
, const struct tcphdr
*th
,
461 struct sock
*cookie_v4_check(struct sock
*sk
, struct sk_buff
*skb
);
462 #ifdef CONFIG_SYN_COOKIES
464 /* Syncookies use a monotonic timer which increments every 60 seconds.
465 * This counter is used both as a hash input and partially encoded into
466 * the cookie value. A cookie is only validated further if the delta
467 * between the current counter value and the encoded one is less than this,
468 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if
469 * the counter advances immediately after a cookie is generated).
471 #define MAX_SYNCOOKIE_AGE 2
472 #define TCP_SYNCOOKIE_PERIOD (60 * HZ)
473 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD)
475 /* syncookies: remember time of last synqueue overflow
476 * But do not dirty this field too often (once per second is enough)
477 * It is racy as we do not hold a lock, but race is very minor.
479 static inline void tcp_synq_overflow(const struct sock
*sk
)
481 unsigned int last_overflow
;
482 unsigned int now
= jiffies
;
484 if (sk
->sk_reuseport
) {
485 struct sock_reuseport
*reuse
;
487 reuse
= rcu_dereference(sk
->sk_reuseport_cb
);
489 last_overflow
= READ_ONCE(reuse
->synq_overflow_ts
);
490 if (time_after32(now
, last_overflow
+ HZ
))
491 WRITE_ONCE(reuse
->synq_overflow_ts
, now
);
496 last_overflow
= tcp_sk(sk
)->rx_opt
.ts_recent_stamp
;
497 if (time_after32(now
, last_overflow
+ HZ
))
498 tcp_sk(sk
)->rx_opt
.ts_recent_stamp
= now
;
501 /* syncookies: no recent synqueue overflow on this listening socket? */
502 static inline bool tcp_synq_no_recent_overflow(const struct sock
*sk
)
504 unsigned int last_overflow
;
505 unsigned int now
= jiffies
;
507 if (sk
->sk_reuseport
) {
508 struct sock_reuseport
*reuse
;
510 reuse
= rcu_dereference(sk
->sk_reuseport_cb
);
512 last_overflow
= READ_ONCE(reuse
->synq_overflow_ts
);
513 return time_after32(now
, last_overflow
+
514 TCP_SYNCOOKIE_VALID
);
518 last_overflow
= tcp_sk(sk
)->rx_opt
.ts_recent_stamp
;
519 return time_after32(now
, last_overflow
+ TCP_SYNCOOKIE_VALID
);
522 static inline u32
tcp_cookie_time(void)
524 u64 val
= get_jiffies_64();
526 do_div(val
, TCP_SYNCOOKIE_PERIOD
);
530 u32
__cookie_v4_init_sequence(const struct iphdr
*iph
, const struct tcphdr
*th
,
532 __u32
cookie_v4_init_sequence(const struct sk_buff
*skb
, __u16
*mss
);
533 u64
cookie_init_timestamp(struct request_sock
*req
);
534 bool cookie_timestamp_decode(const struct net
*net
,
535 struct tcp_options_received
*opt
);
536 bool cookie_ecn_ok(const struct tcp_options_received
*opt
,
537 const struct net
*net
, const struct dst_entry
*dst
);
539 /* From net/ipv6/syncookies.c */
540 int __cookie_v6_check(const struct ipv6hdr
*iph
, const struct tcphdr
*th
,
542 struct sock
*cookie_v6_check(struct sock
*sk
, struct sk_buff
*skb
);
544 u32
__cookie_v6_init_sequence(const struct ipv6hdr
*iph
,
545 const struct tcphdr
*th
, u16
*mssp
);
546 __u32
cookie_v6_init_sequence(const struct sk_buff
*skb
, __u16
*mss
);
550 void __tcp_push_pending_frames(struct sock
*sk
, unsigned int cur_mss
,
552 int __tcp_retransmit_skb(struct sock
*sk
, struct sk_buff
*skb
, int segs
);
553 int tcp_retransmit_skb(struct sock
*sk
, struct sk_buff
*skb
, int segs
);
554 void tcp_retransmit_timer(struct sock
*sk
);
555 void tcp_xmit_retransmit_queue(struct sock
*);
556 void tcp_simple_retransmit(struct sock
*);
557 void tcp_enter_recovery(struct sock
*sk
, bool ece_ack
);
558 int tcp_trim_head(struct sock
*, struct sk_buff
*, u32
);
560 TCP_FRAG_IN_WRITE_QUEUE
,
561 TCP_FRAG_IN_RTX_QUEUE
,
563 int tcp_fragment(struct sock
*sk
, enum tcp_queue tcp_queue
,
564 struct sk_buff
*skb
, u32 len
,
565 unsigned int mss_now
, gfp_t gfp
);
567 void tcp_send_probe0(struct sock
*);
568 void tcp_send_partial(struct sock
*);
569 int tcp_write_wakeup(struct sock
*, int mib
);
570 void tcp_send_fin(struct sock
*sk
);
571 void tcp_send_active_reset(struct sock
*sk
, gfp_t priority
);
572 int tcp_send_synack(struct sock
*);
573 void tcp_push_one(struct sock
*, unsigned int mss_now
);
574 void __tcp_send_ack(struct sock
*sk
, u32 rcv_nxt
);
575 void tcp_send_ack(struct sock
*sk
);
576 void tcp_send_delayed_ack(struct sock
*sk
);
577 void tcp_send_loss_probe(struct sock
*sk
);
578 bool tcp_schedule_loss_probe(struct sock
*sk
, bool advancing_rto
);
579 void tcp_skb_collapse_tstamp(struct sk_buff
*skb
,
580 const struct sk_buff
*next_skb
);
583 void tcp_rearm_rto(struct sock
*sk
);
584 void tcp_synack_rtt_meas(struct sock
*sk
, struct request_sock
*req
);
585 void tcp_reset(struct sock
*sk
);
586 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock
*tp
, struct sk_buff
*skb
);
587 void tcp_fin(struct sock
*sk
);
590 void tcp_init_xmit_timers(struct sock
*);
591 static inline void tcp_clear_xmit_timers(struct sock
*sk
)
593 if (hrtimer_try_to_cancel(&tcp_sk(sk
)->pacing_timer
) == 1)
596 if (hrtimer_try_to_cancel(&tcp_sk(sk
)->compressed_ack_timer
) == 1)
599 inet_csk_clear_xmit_timers(sk
);
602 unsigned int tcp_sync_mss(struct sock
*sk
, u32 pmtu
);
603 unsigned int tcp_current_mss(struct sock
*sk
);
605 /* Bound MSS / TSO packet size with the half of the window */
606 static inline int tcp_bound_to_half_wnd(struct tcp_sock
*tp
, int pktsize
)
610 /* When peer uses tiny windows, there is no use in packetizing
611 * to sub-MSS pieces for the sake of SWS or making sure there
612 * are enough packets in the pipe for fast recovery.
614 * On the other hand, for extremely large MSS devices, handling
615 * smaller than MSS windows in this way does make sense.
617 if (tp
->max_window
> TCP_MSS_DEFAULT
)
618 cutoff
= (tp
->max_window
>> 1);
620 cutoff
= tp
->max_window
;
622 if (cutoff
&& pktsize
> cutoff
)
623 return max_t(int, cutoff
, 68U - tp
->tcp_header_len
);
629 void tcp_get_info(struct sock
*, struct tcp_info
*);
631 /* Read 'sendfile()'-style from a TCP socket */
632 int tcp_read_sock(struct sock
*sk
, read_descriptor_t
*desc
,
633 sk_read_actor_t recv_actor
);
635 void tcp_initialize_rcv_mss(struct sock
*sk
);
637 int tcp_mtu_to_mss(struct sock
*sk
, int pmtu
);
638 int tcp_mss_to_mtu(struct sock
*sk
, int mss
);
639 void tcp_mtup_init(struct sock
*sk
);
640 void tcp_init_buffer_space(struct sock
*sk
);
642 static inline void tcp_bound_rto(const struct sock
*sk
)
644 if (inet_csk(sk
)->icsk_rto
> TCP_RTO_MAX
)
645 inet_csk(sk
)->icsk_rto
= TCP_RTO_MAX
;
648 static inline u32
__tcp_set_rto(const struct tcp_sock
*tp
)
650 return usecs_to_jiffies((tp
->srtt_us
>> 3) + tp
->rttvar_us
);
653 static inline void __tcp_fast_path_on(struct tcp_sock
*tp
, u32 snd_wnd
)
655 tp
->pred_flags
= htonl((tp
->tcp_header_len
<< 26) |
656 ntohl(TCP_FLAG_ACK
) |
660 static inline void tcp_fast_path_on(struct tcp_sock
*tp
)
662 __tcp_fast_path_on(tp
, tp
->snd_wnd
>> tp
->rx_opt
.snd_wscale
);
665 static inline void tcp_fast_path_check(struct sock
*sk
)
667 struct tcp_sock
*tp
= tcp_sk(sk
);
669 if (RB_EMPTY_ROOT(&tp
->out_of_order_queue
) &&
671 atomic_read(&sk
->sk_rmem_alloc
) < sk
->sk_rcvbuf
&&
673 tcp_fast_path_on(tp
);
676 /* Compute the actual rto_min value */
677 static inline u32
tcp_rto_min(struct sock
*sk
)
679 const struct dst_entry
*dst
= __sk_dst_get(sk
);
680 u32 rto_min
= TCP_RTO_MIN
;
682 if (dst
&& dst_metric_locked(dst
, RTAX_RTO_MIN
))
683 rto_min
= dst_metric_rtt(dst
, RTAX_RTO_MIN
);
687 static inline u32
tcp_rto_min_us(struct sock
*sk
)
689 return jiffies_to_usecs(tcp_rto_min(sk
));
692 static inline bool tcp_ca_dst_locked(const struct dst_entry
*dst
)
694 return dst_metric_locked(dst
, RTAX_CC_ALGO
);
697 /* Minimum RTT in usec. ~0 means not available. */
698 static inline u32
tcp_min_rtt(const struct tcp_sock
*tp
)
700 return minmax_get(&tp
->rtt_min
);
703 /* Compute the actual receive window we are currently advertising.
704 * Rcv_nxt can be after the window if our peer push more data
705 * than the offered window.
707 static inline u32
tcp_receive_window(const struct tcp_sock
*tp
)
709 s32 win
= tp
->rcv_wup
+ tp
->rcv_wnd
- tp
->rcv_nxt
;
716 /* Choose a new window, without checks for shrinking, and without
717 * scaling applied to the result. The caller does these things
718 * if necessary. This is a "raw" window selection.
720 u32
__tcp_select_window(struct sock
*sk
);
722 void tcp_send_window_probe(struct sock
*sk
);
724 /* TCP uses 32bit jiffies to save some space.
725 * Note that this is different from tcp_time_stamp, which
726 * historically has been the same until linux-4.13.
728 #define tcp_jiffies32 ((u32)jiffies)
731 * Deliver a 32bit value for TCP timestamp option (RFC 7323)
732 * It is no longer tied to jiffies, but to 1 ms clock.
733 * Note: double check if you want to use tcp_jiffies32 instead of this.
735 #define TCP_TS_HZ 1000
737 static inline u64
tcp_clock_ns(void)
739 return ktime_get_ns();
742 static inline u64
tcp_clock_us(void)
744 return div_u64(tcp_clock_ns(), NSEC_PER_USEC
);
747 /* This should only be used in contexts where tp->tcp_mstamp is up to date */
748 static inline u32
tcp_time_stamp(const struct tcp_sock
*tp
)
750 return div_u64(tp
->tcp_mstamp
, USEC_PER_SEC
/ TCP_TS_HZ
);
753 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */
754 static inline u32
tcp_time_stamp_raw(void)
756 return div_u64(tcp_clock_ns(), NSEC_PER_SEC
/ TCP_TS_HZ
);
759 void tcp_mstamp_refresh(struct tcp_sock
*tp
);
761 static inline u32
tcp_stamp_us_delta(u64 t1
, u64 t0
)
763 return max_t(s64
, t1
- t0
, 0);
766 static inline u32
tcp_skb_timestamp(const struct sk_buff
*skb
)
768 return div_u64(skb
->skb_mstamp_ns
, NSEC_PER_SEC
/ TCP_TS_HZ
);
771 /* provide the departure time in us unit */
772 static inline u64
tcp_skb_timestamp_us(const struct sk_buff
*skb
)
774 return div_u64(skb
->skb_mstamp_ns
, NSEC_PER_USEC
);
778 #define tcp_flag_byte(th) (((u_int8_t *)th)[13])
780 #define TCPHDR_FIN 0x01
781 #define TCPHDR_SYN 0x02
782 #define TCPHDR_RST 0x04
783 #define TCPHDR_PSH 0x08
784 #define TCPHDR_ACK 0x10
785 #define TCPHDR_URG 0x20
786 #define TCPHDR_ECE 0x40
787 #define TCPHDR_CWR 0x80
789 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR)
791 /* This is what the send packet queuing engine uses to pass
792 * TCP per-packet control information to the transmission code.
793 * We also store the host-order sequence numbers in here too.
794 * This is 44 bytes if IPV6 is enabled.
795 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
798 __u32 seq
; /* Starting sequence number */
799 __u32 end_seq
; /* SEQ + FIN + SYN + datalen */
801 /* Note : tcp_tw_isn is used in input path only
802 * (isn chosen by tcp_timewait_state_process())
804 * tcp_gso_segs/size are used in write queue only,
805 * cf tcp_skb_pcount()/tcp_skb_mss()
813 __u8 tcp_flags
; /* TCP header flags. (tcp[13]) */
815 __u8 sacked
; /* State flags for SACK. */
816 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
817 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
818 #define TCPCB_LOST 0x04 /* SKB is lost */
819 #define TCPCB_TAGBITS 0x07 /* All tag bits */
820 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */
821 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
822 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
825 __u8 ip_dsfield
; /* IPv4 tos or IPv6 dsfield */
826 __u8 txstamp_ack
:1, /* Record TX timestamp for ack? */
827 eor
:1, /* Is skb MSG_EOR marked? */
828 has_rxtstamp
:1, /* SKB has a RX timestamp */
830 __u32 ack_seq
; /* Sequence number ACK'd */
833 /* There is space for up to 24 bytes */
834 __u32 in_flight
:30,/* Bytes in flight at transmit */
835 is_app_limited
:1, /* cwnd not fully used? */
837 /* pkts S/ACKed so far upon tx of skb, incl retrans: */
839 /* start of send pipeline phase */
841 /* when we reached the "delivered" count */
842 u64 delivered_mstamp
;
843 } tx
; /* only used for outgoing skbs */
845 struct inet_skb_parm h4
;
846 #if IS_ENABLED(CONFIG_IPV6)
847 struct inet6_skb_parm h6
;
849 } header
; /* For incoming skbs */
852 struct sock
*sk_redir
;
858 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
860 static inline void bpf_compute_data_end_sk_skb(struct sk_buff
*skb
)
862 TCP_SKB_CB(skb
)->bpf
.data_end
= skb
->data
+ skb_headlen(skb
);
865 static inline bool tcp_skb_bpf_ingress(const struct sk_buff
*skb
)
867 return TCP_SKB_CB(skb
)->bpf
.flags
& BPF_F_INGRESS
;
870 static inline struct sock
*tcp_skb_bpf_redirect_fetch(struct sk_buff
*skb
)
872 return TCP_SKB_CB(skb
)->bpf
.sk_redir
;
875 static inline void tcp_skb_bpf_redirect_clear(struct sk_buff
*skb
)
877 TCP_SKB_CB(skb
)->bpf
.sk_redir
= NULL
;
880 #if IS_ENABLED(CONFIG_IPV6)
881 /* This is the variant of inet6_iif() that must be used by TCP,
882 * as TCP moves IP6CB into a different location in skb->cb[]
884 static inline int tcp_v6_iif(const struct sk_buff
*skb
)
886 return TCP_SKB_CB(skb
)->header
.h6
.iif
;
889 static inline int tcp_v6_iif_l3_slave(const struct sk_buff
*skb
)
891 bool l3_slave
= ipv6_l3mdev_skb(TCP_SKB_CB(skb
)->header
.h6
.flags
);
893 return l3_slave
? skb
->skb_iif
: TCP_SKB_CB(skb
)->header
.h6
.iif
;
896 /* TCP_SKB_CB reference means this can not be used from early demux */
897 static inline int tcp_v6_sdif(const struct sk_buff
*skb
)
899 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
900 if (skb
&& ipv6_l3mdev_skb(TCP_SKB_CB(skb
)->header
.h6
.flags
))
901 return TCP_SKB_CB(skb
)->header
.h6
.iif
;
907 static inline bool inet_exact_dif_match(struct net
*net
, struct sk_buff
*skb
)
909 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
910 if (!net
->ipv4
.sysctl_tcp_l3mdev_accept
&&
911 skb
&& ipv4_l3mdev_skb(IPCB(skb
)->flags
))
917 /* TCP_SKB_CB reference means this can not be used from early demux */
918 static inline int tcp_v4_sdif(struct sk_buff
*skb
)
920 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
921 if (skb
&& ipv4_l3mdev_skb(TCP_SKB_CB(skb
)->header
.h4
.flags
))
922 return TCP_SKB_CB(skb
)->header
.h4
.iif
;
927 /* Due to TSO, an SKB can be composed of multiple actual
928 * packets. To keep these tracked properly, we use this.
930 static inline int tcp_skb_pcount(const struct sk_buff
*skb
)
932 return TCP_SKB_CB(skb
)->tcp_gso_segs
;
935 static inline void tcp_skb_pcount_set(struct sk_buff
*skb
, int segs
)
937 TCP_SKB_CB(skb
)->tcp_gso_segs
= segs
;
940 static inline void tcp_skb_pcount_add(struct sk_buff
*skb
, int segs
)
942 TCP_SKB_CB(skb
)->tcp_gso_segs
+= segs
;
945 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
946 static inline int tcp_skb_mss(const struct sk_buff
*skb
)
948 return TCP_SKB_CB(skb
)->tcp_gso_size
;
951 static inline bool tcp_skb_can_collapse_to(const struct sk_buff
*skb
)
953 return likely(!TCP_SKB_CB(skb
)->eor
);
956 /* Events passed to congestion control interface */
958 CA_EVENT_TX_START
, /* first transmit when no packets in flight */
959 CA_EVENT_CWND_RESTART
, /* congestion window restart */
960 CA_EVENT_COMPLETE_CWR
, /* end of congestion recovery */
961 CA_EVENT_LOSS
, /* loss timeout */
962 CA_EVENT_ECN_NO_CE
, /* ECT set, but not CE marked */
963 CA_EVENT_ECN_IS_CE
, /* received CE marked IP packet */
966 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */
967 enum tcp_ca_ack_event_flags
{
968 CA_ACK_SLOWPATH
= (1 << 0), /* In slow path processing */
969 CA_ACK_WIN_UPDATE
= (1 << 1), /* ACK updated window */
970 CA_ACK_ECE
= (1 << 2), /* ECE bit is set on ack */
974 * Interface for adding new TCP congestion control handlers
976 #define TCP_CA_NAME_MAX 16
977 #define TCP_CA_MAX 128
978 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
980 #define TCP_CA_UNSPEC 0
982 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */
983 #define TCP_CONG_NON_RESTRICTED 0x1
984 /* Requires ECN/ECT set on all packets */
985 #define TCP_CONG_NEEDS_ECN 0x2
995 /* A rate sample measures the number of (original/retransmitted) data
996 * packets delivered "delivered" over an interval of time "interval_us".
997 * The tcp_rate.c code fills in the rate sample, and congestion
998 * control modules that define a cong_control function to run at the end
999 * of ACK processing can optionally chose to consult this sample when
1000 * setting cwnd and pacing rate.
1001 * A sample is invalid if "delivered" or "interval_us" is negative.
1003 struct rate_sample
{
1004 u64 prior_mstamp
; /* starting timestamp for interval */
1005 u32 prior_delivered
; /* tp->delivered at "prior_mstamp" */
1006 s32 delivered
; /* number of packets delivered over interval */
1007 long interval_us
; /* time for tp->delivered to incr "delivered" */
1008 u32 snd_interval_us
; /* snd interval for delivered packets */
1009 u32 rcv_interval_us
; /* rcv interval for delivered packets */
1010 long rtt_us
; /* RTT of last (S)ACKed packet (or -1) */
1011 int losses
; /* number of packets marked lost upon ACK */
1012 u32 acked_sacked
; /* number of packets newly (S)ACKed upon ACK */
1013 u32 prior_in_flight
; /* in flight before this ACK */
1014 bool is_app_limited
; /* is sample from packet with bubble in pipe? */
1015 bool is_retrans
; /* is sample from retransmission? */
1016 bool is_ack_delayed
; /* is this (likely) a delayed ACK? */
1019 struct tcp_congestion_ops
{
1020 struct list_head list
;
1024 /* initialize private data (optional) */
1025 void (*init
)(struct sock
*sk
);
1026 /* cleanup private data (optional) */
1027 void (*release
)(struct sock
*sk
);
1029 /* return slow start threshold (required) */
1030 u32 (*ssthresh
)(struct sock
*sk
);
1031 /* do new cwnd calculation (required) */
1032 void (*cong_avoid
)(struct sock
*sk
, u32 ack
, u32 acked
);
1033 /* call before changing ca_state (optional) */
1034 void (*set_state
)(struct sock
*sk
, u8 new_state
);
1035 /* call when cwnd event occurs (optional) */
1036 void (*cwnd_event
)(struct sock
*sk
, enum tcp_ca_event ev
);
1037 /* call when ack arrives (optional) */
1038 void (*in_ack_event
)(struct sock
*sk
, u32 flags
);
1039 /* new value of cwnd after loss (required) */
1040 u32 (*undo_cwnd
)(struct sock
*sk
);
1041 /* hook for packet ack accounting (optional) */
1042 void (*pkts_acked
)(struct sock
*sk
, const struct ack_sample
*sample
);
1043 /* override sysctl_tcp_min_tso_segs */
1044 u32 (*min_tso_segs
)(struct sock
*sk
);
1045 /* returns the multiplier used in tcp_sndbuf_expand (optional) */
1046 u32 (*sndbuf_expand
)(struct sock
*sk
);
1047 /* call when packets are delivered to update cwnd and pacing rate,
1048 * after all the ca_state processing. (optional)
1050 void (*cong_control
)(struct sock
*sk
, const struct rate_sample
*rs
);
1051 /* get info for inet_diag (optional) */
1052 size_t (*get_info
)(struct sock
*sk
, u32 ext
, int *attr
,
1053 union tcp_cc_info
*info
);
1055 char name
[TCP_CA_NAME_MAX
];
1056 struct module
*owner
;
1059 int tcp_register_congestion_control(struct tcp_congestion_ops
*type
);
1060 void tcp_unregister_congestion_control(struct tcp_congestion_ops
*type
);
1062 void tcp_assign_congestion_control(struct sock
*sk
);
1063 void tcp_init_congestion_control(struct sock
*sk
);
1064 void tcp_cleanup_congestion_control(struct sock
*sk
);
1065 int tcp_set_default_congestion_control(struct net
*net
, const char *name
);
1066 void tcp_get_default_congestion_control(struct net
*net
, char *name
);
1067 void tcp_get_available_congestion_control(char *buf
, size_t len
);
1068 void tcp_get_allowed_congestion_control(char *buf
, size_t len
);
1069 int tcp_set_allowed_congestion_control(char *allowed
);
1070 int tcp_set_congestion_control(struct sock
*sk
, const char *name
, bool load
, bool reinit
);
1071 u32
tcp_slow_start(struct tcp_sock
*tp
, u32 acked
);
1072 void tcp_cong_avoid_ai(struct tcp_sock
*tp
, u32 w
, u32 acked
);
1074 u32
tcp_reno_ssthresh(struct sock
*sk
);
1075 u32
tcp_reno_undo_cwnd(struct sock
*sk
);
1076 void tcp_reno_cong_avoid(struct sock
*sk
, u32 ack
, u32 acked
);
1077 extern struct tcp_congestion_ops tcp_reno
;
1079 struct tcp_congestion_ops
*tcp_ca_find_key(u32 key
);
1080 u32
tcp_ca_get_key_by_name(struct net
*net
, const char *name
, bool *ecn_ca
);
1082 char *tcp_ca_get_name_by_key(u32 key
, char *buffer
);
1084 static inline char *tcp_ca_get_name_by_key(u32 key
, char *buffer
)
1090 static inline bool tcp_ca_needs_ecn(const struct sock
*sk
)
1092 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
1094 return icsk
->icsk_ca_ops
->flags
& TCP_CONG_NEEDS_ECN
;
1097 static inline void tcp_set_ca_state(struct sock
*sk
, const u8 ca_state
)
1099 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1101 if (icsk
->icsk_ca_ops
->set_state
)
1102 icsk
->icsk_ca_ops
->set_state(sk
, ca_state
);
1103 icsk
->icsk_ca_state
= ca_state
;
1106 static inline void tcp_ca_event(struct sock
*sk
, const enum tcp_ca_event event
)
1108 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
1110 if (icsk
->icsk_ca_ops
->cwnd_event
)
1111 icsk
->icsk_ca_ops
->cwnd_event(sk
, event
);
1114 /* From tcp_rate.c */
1115 void tcp_rate_skb_sent(struct sock
*sk
, struct sk_buff
*skb
);
1116 void tcp_rate_skb_delivered(struct sock
*sk
, struct sk_buff
*skb
,
1117 struct rate_sample
*rs
);
1118 void tcp_rate_gen(struct sock
*sk
, u32 delivered
, u32 lost
,
1119 bool is_sack_reneg
, struct rate_sample
*rs
);
1120 void tcp_rate_check_app_limited(struct sock
*sk
);
1122 /* These functions determine how the current flow behaves in respect of SACK
1123 * handling. SACK is negotiated with the peer, and therefore it can vary
1124 * between different flows.
1126 * tcp_is_sack - SACK enabled
1127 * tcp_is_reno - No SACK
1129 static inline int tcp_is_sack(const struct tcp_sock
*tp
)
1131 return likely(tp
->rx_opt
.sack_ok
);
1134 static inline bool tcp_is_reno(const struct tcp_sock
*tp
)
1136 return !tcp_is_sack(tp
);
1139 static inline unsigned int tcp_left_out(const struct tcp_sock
*tp
)
1141 return tp
->sacked_out
+ tp
->lost_out
;
1144 /* This determines how many packets are "in the network" to the best
1145 * of our knowledge. In many cases it is conservative, but where
1146 * detailed information is available from the receiver (via SACK
1147 * blocks etc.) we can make more aggressive calculations.
1149 * Use this for decisions involving congestion control, use just
1150 * tp->packets_out to determine if the send queue is empty or not.
1152 * Read this equation as:
1154 * "Packets sent once on transmission queue" MINUS
1155 * "Packets left network, but not honestly ACKed yet" PLUS
1156 * "Packets fast retransmitted"
1158 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock
*tp
)
1160 return tp
->packets_out
- tcp_left_out(tp
) + tp
->retrans_out
;
1163 #define TCP_INFINITE_SSTHRESH 0x7fffffff
1165 static inline bool tcp_in_slow_start(const struct tcp_sock
*tp
)
1167 return tp
->snd_cwnd
< tp
->snd_ssthresh
;
1170 static inline bool tcp_in_initial_slowstart(const struct tcp_sock
*tp
)
1172 return tp
->snd_ssthresh
>= TCP_INFINITE_SSTHRESH
;
1175 static inline bool tcp_in_cwnd_reduction(const struct sock
*sk
)
1177 return (TCPF_CA_CWR
| TCPF_CA_Recovery
) &
1178 (1 << inet_csk(sk
)->icsk_ca_state
);
1181 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
1182 * The exception is cwnd reduction phase, when cwnd is decreasing towards
1185 static inline __u32
tcp_current_ssthresh(const struct sock
*sk
)
1187 const struct tcp_sock
*tp
= tcp_sk(sk
);
1189 if (tcp_in_cwnd_reduction(sk
))
1190 return tp
->snd_ssthresh
;
1192 return max(tp
->snd_ssthresh
,
1193 ((tp
->snd_cwnd
>> 1) +
1194 (tp
->snd_cwnd
>> 2)));
1197 /* Use define here intentionally to get WARN_ON location shown at the caller */
1198 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
1200 void tcp_enter_cwr(struct sock
*sk
);
1201 __u32
tcp_init_cwnd(const struct tcp_sock
*tp
, const struct dst_entry
*dst
);
1203 /* The maximum number of MSS of available cwnd for which TSO defers
1204 * sending if not using sysctl_tcp_tso_win_divisor.
1206 static inline __u32
tcp_max_tso_deferred_mss(const struct tcp_sock
*tp
)
1211 /* Returns end sequence number of the receiver's advertised window */
1212 static inline u32
tcp_wnd_end(const struct tcp_sock
*tp
)
1214 return tp
->snd_una
+ tp
->snd_wnd
;
1217 /* We follow the spirit of RFC2861 to validate cwnd but implement a more
1218 * flexible approach. The RFC suggests cwnd should not be raised unless
1219 * it was fully used previously. And that's exactly what we do in
1220 * congestion avoidance mode. But in slow start we allow cwnd to grow
1221 * as long as the application has used half the cwnd.
1223 * cwnd is 10 (IW10), but application sends 9 frames.
1224 * We allow cwnd to reach 18 when all frames are ACKed.
1225 * This check is safe because it's as aggressive as slow start which already
1226 * risks 100% overshoot. The advantage is that we discourage application to
1227 * either send more filler packets or data to artificially blow up the cwnd
1228 * usage, and allow application-limited process to probe bw more aggressively.
1230 static inline bool tcp_is_cwnd_limited(const struct sock
*sk
)
1232 const struct tcp_sock
*tp
= tcp_sk(sk
);
1234 /* If in slow start, ensure cwnd grows to twice what was ACKed. */
1235 if (tcp_in_slow_start(tp
))
1236 return tp
->snd_cwnd
< 2 * tp
->max_packets_out
;
1238 return tp
->is_cwnd_limited
;
1241 /* BBR congestion control needs pacing.
1242 * Same remark for SO_MAX_PACING_RATE.
1243 * sch_fq packet scheduler is efficiently handling pacing,
1244 * but is not always installed/used.
1245 * Return true if TCP stack should pace packets itself.
1247 static inline bool tcp_needs_internal_pacing(const struct sock
*sk
)
1249 return smp_load_acquire(&sk
->sk_pacing_status
) == SK_PACING_NEEDED
;
1252 /* Return in jiffies the delay before one skb is sent.
1253 * If @skb is NULL, we look at EDT for next packet being sent on the socket.
1255 static inline unsigned long tcp_pacing_delay(const struct sock
*sk
,
1256 const struct sk_buff
*skb
)
1258 s64 pacing_delay
= skb
? skb
->tstamp
: tcp_sk(sk
)->tcp_wstamp_ns
;
1260 pacing_delay
-= tcp_sk(sk
)->tcp_clock_cache
;
1262 return pacing_delay
> 0 ? nsecs_to_jiffies(pacing_delay
) : 0;
1265 static inline void tcp_reset_xmit_timer(struct sock
*sk
,
1268 const unsigned long max_when
,
1269 const struct sk_buff
*skb
)
1271 inet_csk_reset_xmit_timer(sk
, what
, when
+ tcp_pacing_delay(sk
, skb
),
1275 /* Something is really bad, we could not queue an additional packet,
1276 * because qdisc is full or receiver sent a 0 window, or we are paced.
1277 * We do not want to add fuel to the fire, or abort too early,
1278 * so make sure the timer we arm now is at least 200ms in the future,
1279 * regardless of current icsk_rto value (as it could be ~2ms)
1281 static inline unsigned long tcp_probe0_base(const struct sock
*sk
)
1283 return max_t(unsigned long, inet_csk(sk
)->icsk_rto
, TCP_RTO_MIN
);
1286 /* Variant of inet_csk_rto_backoff() used for zero window probes */
1287 static inline unsigned long tcp_probe0_when(const struct sock
*sk
,
1288 unsigned long max_when
)
1290 u64 when
= (u64
)tcp_probe0_base(sk
) << inet_csk(sk
)->icsk_backoff
;
1292 return (unsigned long)min_t(u64
, when
, max_when
);
1295 static inline void tcp_check_probe_timer(struct sock
*sk
)
1297 if (!tcp_sk(sk
)->packets_out
&& !inet_csk(sk
)->icsk_pending
)
1298 tcp_reset_xmit_timer(sk
, ICSK_TIME_PROBE0
,
1299 tcp_probe0_base(sk
), TCP_RTO_MAX
,
1303 static inline void tcp_init_wl(struct tcp_sock
*tp
, u32 seq
)
1308 static inline void tcp_update_wl(struct tcp_sock
*tp
, u32 seq
)
1314 * Calculate(/check) TCP checksum
1316 static inline __sum16
tcp_v4_check(int len
, __be32 saddr
,
1317 __be32 daddr
, __wsum base
)
1319 return csum_tcpudp_magic(saddr
,daddr
,len
,IPPROTO_TCP
,base
);
1322 static inline bool tcp_checksum_complete(struct sk_buff
*skb
)
1324 return !skb_csum_unnecessary(skb
) &&
1325 __skb_checksum_complete(skb
);
1328 bool tcp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
);
1329 int tcp_filter(struct sock
*sk
, struct sk_buff
*skb
);
1330 void tcp_set_state(struct sock
*sk
, int state
);
1331 void tcp_done(struct sock
*sk
);
1332 int tcp_abort(struct sock
*sk
, int err
);
1334 static inline void tcp_sack_reset(struct tcp_options_received
*rx_opt
)
1337 rx_opt
->num_sacks
= 0;
1340 u32
tcp_default_init_rwnd(u32 mss
);
1341 void tcp_cwnd_restart(struct sock
*sk
, s32 delta
);
1343 static inline void tcp_slow_start_after_idle_check(struct sock
*sk
)
1345 const struct tcp_congestion_ops
*ca_ops
= inet_csk(sk
)->icsk_ca_ops
;
1346 struct tcp_sock
*tp
= tcp_sk(sk
);
1349 if (!sock_net(sk
)->ipv4
.sysctl_tcp_slow_start_after_idle
|| tp
->packets_out
||
1350 ca_ops
->cong_control
)
1352 delta
= tcp_jiffies32
- tp
->lsndtime
;
1353 if (delta
> inet_csk(sk
)->icsk_rto
)
1354 tcp_cwnd_restart(sk
, delta
);
1357 /* Determine a window scaling and initial window to offer. */
1358 void tcp_select_initial_window(const struct sock
*sk
, int __space
,
1359 __u32 mss
, __u32
*rcv_wnd
,
1360 __u32
*window_clamp
, int wscale_ok
,
1361 __u8
*rcv_wscale
, __u32 init_rcv_wnd
);
1363 static inline int tcp_win_from_space(const struct sock
*sk
, int space
)
1365 int tcp_adv_win_scale
= sock_net(sk
)->ipv4
.sysctl_tcp_adv_win_scale
;
1367 return tcp_adv_win_scale
<= 0 ?
1368 (space
>>(-tcp_adv_win_scale
)) :
1369 space
- (space
>>tcp_adv_win_scale
);
1372 /* Note: caller must be prepared to deal with negative returns */
1373 static inline int tcp_space(const struct sock
*sk
)
1375 return tcp_win_from_space(sk
, sk
->sk_rcvbuf
- sk
->sk_backlog
.len
-
1376 atomic_read(&sk
->sk_rmem_alloc
));
1379 static inline int tcp_full_space(const struct sock
*sk
)
1381 return tcp_win_from_space(sk
, sk
->sk_rcvbuf
);
1384 extern void tcp_openreq_init_rwin(struct request_sock
*req
,
1385 const struct sock
*sk_listener
,
1386 const struct dst_entry
*dst
);
1388 void tcp_enter_memory_pressure(struct sock
*sk
);
1389 void tcp_leave_memory_pressure(struct sock
*sk
);
1391 static inline int keepalive_intvl_when(const struct tcp_sock
*tp
)
1393 struct net
*net
= sock_net((struct sock
*)tp
);
1395 return tp
->keepalive_intvl
? : net
->ipv4
.sysctl_tcp_keepalive_intvl
;
1398 static inline int keepalive_time_when(const struct tcp_sock
*tp
)
1400 struct net
*net
= sock_net((struct sock
*)tp
);
1402 return tp
->keepalive_time
? : net
->ipv4
.sysctl_tcp_keepalive_time
;
1405 static inline int keepalive_probes(const struct tcp_sock
*tp
)
1407 struct net
*net
= sock_net((struct sock
*)tp
);
1409 return tp
->keepalive_probes
? : net
->ipv4
.sysctl_tcp_keepalive_probes
;
1412 static inline u32
keepalive_time_elapsed(const struct tcp_sock
*tp
)
1414 const struct inet_connection_sock
*icsk
= &tp
->inet_conn
;
1416 return min_t(u32
, tcp_jiffies32
- icsk
->icsk_ack
.lrcvtime
,
1417 tcp_jiffies32
- tp
->rcv_tstamp
);
1420 static inline int tcp_fin_time(const struct sock
*sk
)
1422 int fin_timeout
= tcp_sk(sk
)->linger2
? : sock_net(sk
)->ipv4
.sysctl_tcp_fin_timeout
;
1423 const int rto
= inet_csk(sk
)->icsk_rto
;
1425 if (fin_timeout
< (rto
<< 2) - (rto
>> 1))
1426 fin_timeout
= (rto
<< 2) - (rto
>> 1);
1431 static inline bool tcp_paws_check(const struct tcp_options_received
*rx_opt
,
1434 if ((s32
)(rx_opt
->ts_recent
- rx_opt
->rcv_tsval
) <= paws_win
)
1436 if (unlikely(!time_before32(ktime_get_seconds(),
1437 rx_opt
->ts_recent_stamp
+ TCP_PAWS_24DAYS
)))
1440 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0,
1441 * then following tcp messages have valid values. Ignore 0 value,
1442 * or else 'negative' tsval might forbid us to accept their packets.
1444 if (!rx_opt
->ts_recent
)
1449 static inline bool tcp_paws_reject(const struct tcp_options_received
*rx_opt
,
1452 if (tcp_paws_check(rx_opt
, 0))
1455 /* RST segments are not recommended to carry timestamp,
1456 and, if they do, it is recommended to ignore PAWS because
1457 "their cleanup function should take precedence over timestamps."
1458 Certainly, it is mistake. It is necessary to understand the reasons
1459 of this constraint to relax it: if peer reboots, clock may go
1460 out-of-sync and half-open connections will not be reset.
1461 Actually, the problem would be not existing if all
1462 the implementations followed draft about maintaining clock
1463 via reboots. Linux-2.2 DOES NOT!
1465 However, we can relax time bounds for RST segments to MSL.
1467 if (rst
&& !time_before32(ktime_get_seconds(),
1468 rx_opt
->ts_recent_stamp
+ TCP_PAWS_MSL
))
1473 bool tcp_oow_rate_limited(struct net
*net
, const struct sk_buff
*skb
,
1474 int mib_idx
, u32
*last_oow_ack_time
);
1476 static inline void tcp_mib_init(struct net
*net
)
1479 TCP_ADD_STATS(net
, TCP_MIB_RTOALGORITHM
, 1);
1480 TCP_ADD_STATS(net
, TCP_MIB_RTOMIN
, TCP_RTO_MIN
*1000/HZ
);
1481 TCP_ADD_STATS(net
, TCP_MIB_RTOMAX
, TCP_RTO_MAX
*1000/HZ
);
1482 TCP_ADD_STATS(net
, TCP_MIB_MAXCONN
, -1);
1486 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock
*tp
)
1488 tp
->lost_skb_hint
= NULL
;
1491 static inline void tcp_clear_all_retrans_hints(struct tcp_sock
*tp
)
1493 tcp_clear_retrans_hints_partial(tp
);
1494 tp
->retransmit_skb_hint
= NULL
;
1497 union tcp_md5_addr
{
1499 #if IS_ENABLED(CONFIG_IPV6)
1504 /* - key database */
1505 struct tcp_md5sig_key
{
1506 struct hlist_node node
;
1508 u8 family
; /* AF_INET or AF_INET6 */
1509 union tcp_md5_addr addr
;
1511 u8 key
[TCP_MD5SIG_MAXKEYLEN
];
1512 struct rcu_head rcu
;
1516 struct tcp_md5sig_info
{
1517 struct hlist_head head
;
1518 struct rcu_head rcu
;
1521 /* - pseudo header */
1522 struct tcp4_pseudohdr
{
1530 struct tcp6_pseudohdr
{
1531 struct in6_addr saddr
;
1532 struct in6_addr daddr
;
1534 __be32 protocol
; /* including padding */
1537 union tcp_md5sum_block
{
1538 struct tcp4_pseudohdr ip4
;
1539 #if IS_ENABLED(CONFIG_IPV6)
1540 struct tcp6_pseudohdr ip6
;
1544 /* - pool: digest algorithm, hash description and scratch buffer */
1545 struct tcp_md5sig_pool
{
1546 struct ahash_request
*md5_req
;
1551 int tcp_v4_md5_hash_skb(char *md5_hash
, const struct tcp_md5sig_key
*key
,
1552 const struct sock
*sk
, const struct sk_buff
*skb
);
1553 int tcp_md5_do_add(struct sock
*sk
, const union tcp_md5_addr
*addr
,
1554 int family
, u8 prefixlen
, const u8
*newkey
, u8 newkeylen
,
1556 int tcp_md5_do_del(struct sock
*sk
, const union tcp_md5_addr
*addr
,
1557 int family
, u8 prefixlen
);
1558 struct tcp_md5sig_key
*tcp_v4_md5_lookup(const struct sock
*sk
,
1559 const struct sock
*addr_sk
);
1561 #ifdef CONFIG_TCP_MD5SIG
1562 #include <linux/jump_label.h>
1563 extern struct static_key_false tcp_md5_needed
;
1564 struct tcp_md5sig_key
*__tcp_md5_do_lookup(const struct sock
*sk
,
1565 const union tcp_md5_addr
*addr
,
1567 static inline struct tcp_md5sig_key
*
1568 tcp_md5_do_lookup(const struct sock
*sk
,
1569 const union tcp_md5_addr
*addr
,
1572 if (!static_branch_unlikely(&tcp_md5_needed
))
1574 return __tcp_md5_do_lookup(sk
, addr
, family
);
1577 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key)
1579 static inline struct tcp_md5sig_key
*tcp_md5_do_lookup(const struct sock
*sk
,
1580 const union tcp_md5_addr
*addr
,
1585 #define tcp_twsk_md5_key(twsk) NULL
1588 bool tcp_alloc_md5sig_pool(void);
1590 struct tcp_md5sig_pool
*tcp_get_md5sig_pool(void);
1591 static inline void tcp_put_md5sig_pool(void)
1596 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool
*, const struct sk_buff
*,
1597 unsigned int header_len
);
1598 int tcp_md5_hash_key(struct tcp_md5sig_pool
*hp
,
1599 const struct tcp_md5sig_key
*key
);
1601 /* From tcp_fastopen.c */
1602 void tcp_fastopen_cache_get(struct sock
*sk
, u16
*mss
,
1603 struct tcp_fastopen_cookie
*cookie
);
1604 void tcp_fastopen_cache_set(struct sock
*sk
, u16 mss
,
1605 struct tcp_fastopen_cookie
*cookie
, bool syn_lost
,
1607 struct tcp_fastopen_request
{
1608 /* Fast Open cookie. Size 0 means a cookie request */
1609 struct tcp_fastopen_cookie cookie
;
1610 struct msghdr
*data
; /* data in MSG_FASTOPEN */
1612 int copied
; /* queued in tcp_connect() */
1613 struct ubuf_info
*uarg
;
1615 void tcp_free_fastopen_req(struct tcp_sock
*tp
);
1616 void tcp_fastopen_destroy_cipher(struct sock
*sk
);
1617 void tcp_fastopen_ctx_destroy(struct net
*net
);
1618 int tcp_fastopen_reset_cipher(struct net
*net
, struct sock
*sk
,
1619 void *key
, unsigned int len
);
1620 void tcp_fastopen_add_skb(struct sock
*sk
, struct sk_buff
*skb
);
1621 struct sock
*tcp_try_fastopen(struct sock
*sk
, struct sk_buff
*skb
,
1622 struct request_sock
*req
,
1623 struct tcp_fastopen_cookie
*foc
,
1624 const struct dst_entry
*dst
);
1625 void tcp_fastopen_init_key_once(struct net
*net
);
1626 bool tcp_fastopen_cookie_check(struct sock
*sk
, u16
*mss
,
1627 struct tcp_fastopen_cookie
*cookie
);
1628 bool tcp_fastopen_defer_connect(struct sock
*sk
, int *err
);
1629 #define TCP_FASTOPEN_KEY_LENGTH 16
1631 /* Fastopen key context */
1632 struct tcp_fastopen_context
{
1633 struct crypto_cipher
*tfm
;
1634 __u8 key
[TCP_FASTOPEN_KEY_LENGTH
];
1635 struct rcu_head rcu
;
1638 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout
;
1639 void tcp_fastopen_active_disable(struct sock
*sk
);
1640 bool tcp_fastopen_active_should_disable(struct sock
*sk
);
1641 void tcp_fastopen_active_disable_ofo_check(struct sock
*sk
);
1642 void tcp_fastopen_active_detect_blackhole(struct sock
*sk
, bool expired
);
1644 /* Latencies incurred by various limits for a sender. They are
1645 * chronograph-like stats that are mutually exclusive.
1649 TCP_CHRONO_BUSY
, /* Actively sending data (non-empty write queue) */
1650 TCP_CHRONO_RWND_LIMITED
, /* Stalled by insufficient receive window */
1651 TCP_CHRONO_SNDBUF_LIMITED
, /* Stalled by insufficient send buffer */
1655 void tcp_chrono_start(struct sock
*sk
, const enum tcp_chrono type
);
1656 void tcp_chrono_stop(struct sock
*sk
, const enum tcp_chrono type
);
1658 /* This helper is needed, because skb->tcp_tsorted_anchor uses
1659 * the same memory storage than skb->destructor/_skb_refdst
1661 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff
*skb
)
1663 skb
->destructor
= NULL
;
1664 skb
->_skb_refdst
= 0UL;
1667 #define tcp_skb_tsorted_save(skb) { \
1668 unsigned long _save = skb->_skb_refdst; \
1669 skb->_skb_refdst = 0UL;
1671 #define tcp_skb_tsorted_restore(skb) \
1672 skb->_skb_refdst = _save; \
1675 void tcp_write_queue_purge(struct sock
*sk
);
1677 static inline struct sk_buff
*tcp_rtx_queue_head(const struct sock
*sk
)
1679 return skb_rb_first(&sk
->tcp_rtx_queue
);
1682 static inline struct sk_buff
*tcp_rtx_queue_tail(const struct sock
*sk
)
1684 return skb_rb_last(&sk
->tcp_rtx_queue
);
1687 static inline struct sk_buff
*tcp_write_queue_head(const struct sock
*sk
)
1689 return skb_peek(&sk
->sk_write_queue
);
1692 static inline struct sk_buff
*tcp_write_queue_tail(const struct sock
*sk
)
1694 return skb_peek_tail(&sk
->sk_write_queue
);
1697 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1698 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1700 static inline struct sk_buff
*tcp_send_head(const struct sock
*sk
)
1702 return skb_peek(&sk
->sk_write_queue
);
1705 static inline bool tcp_skb_is_last(const struct sock
*sk
,
1706 const struct sk_buff
*skb
)
1708 return skb_queue_is_last(&sk
->sk_write_queue
, skb
);
1711 static inline bool tcp_write_queue_empty(const struct sock
*sk
)
1713 return skb_queue_empty(&sk
->sk_write_queue
);
1716 static inline bool tcp_rtx_queue_empty(const struct sock
*sk
)
1718 return RB_EMPTY_ROOT(&sk
->tcp_rtx_queue
);
1721 static inline bool tcp_rtx_and_write_queues_empty(const struct sock
*sk
)
1723 return tcp_rtx_queue_empty(sk
) && tcp_write_queue_empty(sk
);
1726 static inline void tcp_add_write_queue_tail(struct sock
*sk
, struct sk_buff
*skb
)
1728 __skb_queue_tail(&sk
->sk_write_queue
, skb
);
1730 /* Queue it, remembering where we must start sending. */
1731 if (sk
->sk_write_queue
.next
== skb
)
1732 tcp_chrono_start(sk
, TCP_CHRONO_BUSY
);
1735 /* Insert new before skb on the write queue of sk. */
1736 static inline void tcp_insert_write_queue_before(struct sk_buff
*new,
1737 struct sk_buff
*skb
,
1740 __skb_queue_before(&sk
->sk_write_queue
, skb
, new);
1743 static inline void tcp_unlink_write_queue(struct sk_buff
*skb
, struct sock
*sk
)
1745 tcp_skb_tsorted_anchor_cleanup(skb
);
1746 __skb_unlink(skb
, &sk
->sk_write_queue
);
1749 void tcp_rbtree_insert(struct rb_root
*root
, struct sk_buff
*skb
);
1751 static inline void tcp_rtx_queue_unlink(struct sk_buff
*skb
, struct sock
*sk
)
1753 tcp_skb_tsorted_anchor_cleanup(skb
);
1754 rb_erase(&skb
->rbnode
, &sk
->tcp_rtx_queue
);
1757 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff
*skb
, struct sock
*sk
)
1759 list_del(&skb
->tcp_tsorted_anchor
);
1760 tcp_rtx_queue_unlink(skb
, sk
);
1761 sk_wmem_free_skb(sk
, skb
);
1764 static inline void tcp_push_pending_frames(struct sock
*sk
)
1766 if (tcp_send_head(sk
)) {
1767 struct tcp_sock
*tp
= tcp_sk(sk
);
1769 __tcp_push_pending_frames(sk
, tcp_current_mss(sk
), tp
->nonagle
);
1773 /* Start sequence of the skb just after the highest skb with SACKed
1774 * bit, valid only if sacked_out > 0 or when the caller has ensured
1775 * validity by itself.
1777 static inline u32
tcp_highest_sack_seq(struct tcp_sock
*tp
)
1779 if (!tp
->sacked_out
)
1782 if (tp
->highest_sack
== NULL
)
1785 return TCP_SKB_CB(tp
->highest_sack
)->seq
;
1788 static inline void tcp_advance_highest_sack(struct sock
*sk
, struct sk_buff
*skb
)
1790 tcp_sk(sk
)->highest_sack
= skb_rb_next(skb
);
1793 static inline struct sk_buff
*tcp_highest_sack(struct sock
*sk
)
1795 return tcp_sk(sk
)->highest_sack
;
1798 static inline void tcp_highest_sack_reset(struct sock
*sk
)
1800 tcp_sk(sk
)->highest_sack
= tcp_rtx_queue_head(sk
);
1803 /* Called when old skb is about to be deleted and replaced by new skb */
1804 static inline void tcp_highest_sack_replace(struct sock
*sk
,
1805 struct sk_buff
*old
,
1806 struct sk_buff
*new)
1808 if (old
== tcp_highest_sack(sk
))
1809 tcp_sk(sk
)->highest_sack
= new;
1812 /* This helper checks if socket has IP_TRANSPARENT set */
1813 static inline bool inet_sk_transparent(const struct sock
*sk
)
1815 switch (sk
->sk_state
) {
1817 return inet_twsk(sk
)->tw_transparent
;
1818 case TCP_NEW_SYN_RECV
:
1819 return inet_rsk(inet_reqsk(sk
))->no_srccheck
;
1821 return inet_sk(sk
)->transparent
;
1824 /* Determines whether this is a thin stream (which may suffer from
1825 * increased latency). Used to trigger latency-reducing mechanisms.
1827 static inline bool tcp_stream_is_thin(struct tcp_sock
*tp
)
1829 return tp
->packets_out
< 4 && !tcp_in_initial_slowstart(tp
);
1833 enum tcp_seq_states
{
1834 TCP_SEQ_STATE_LISTENING
,
1835 TCP_SEQ_STATE_ESTABLISHED
,
1838 void *tcp_seq_start(struct seq_file
*seq
, loff_t
*pos
);
1839 void *tcp_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
);
1840 void tcp_seq_stop(struct seq_file
*seq
, void *v
);
1842 struct tcp_seq_afinfo
{
1846 struct tcp_iter_state
{
1847 struct seq_net_private p
;
1848 enum tcp_seq_states state
;
1849 struct sock
*syn_wait_sk
;
1850 int bucket
, offset
, sbucket
, num
;
1854 extern struct request_sock_ops tcp_request_sock_ops
;
1855 extern struct request_sock_ops tcp6_request_sock_ops
;
1857 void tcp_v4_destroy_sock(struct sock
*sk
);
1859 struct sk_buff
*tcp_gso_segment(struct sk_buff
*skb
,
1860 netdev_features_t features
);
1861 struct sk_buff
*tcp_gro_receive(struct list_head
*head
, struct sk_buff
*skb
);
1862 int tcp_gro_complete(struct sk_buff
*skb
);
1864 void __tcp_v4_send_check(struct sk_buff
*skb
, __be32 saddr
, __be32 daddr
);
1866 static inline u32
tcp_notsent_lowat(const struct tcp_sock
*tp
)
1868 struct net
*net
= sock_net((struct sock
*)tp
);
1869 return tp
->notsent_lowat
?: net
->ipv4
.sysctl_tcp_notsent_lowat
;
1872 /* @wake is one when sk_stream_write_space() calls us.
1873 * This sends EPOLLOUT only if notsent_bytes is half the limit.
1874 * This mimics the strategy used in sock_def_write_space().
1876 static inline bool tcp_stream_memory_free(const struct sock
*sk
, int wake
)
1878 const struct tcp_sock
*tp
= tcp_sk(sk
);
1879 u32 notsent_bytes
= tp
->write_seq
- tp
->snd_nxt
;
1881 return (notsent_bytes
<< wake
) < tcp_notsent_lowat(tp
);
1884 #ifdef CONFIG_PROC_FS
1885 int tcp4_proc_init(void);
1886 void tcp4_proc_exit(void);
1889 int tcp_rtx_synack(const struct sock
*sk
, struct request_sock
*req
);
1890 int tcp_conn_request(struct request_sock_ops
*rsk_ops
,
1891 const struct tcp_request_sock_ops
*af_ops
,
1892 struct sock
*sk
, struct sk_buff
*skb
);
1894 /* TCP af-specific functions */
1895 struct tcp_sock_af_ops
{
1896 #ifdef CONFIG_TCP_MD5SIG
1897 struct tcp_md5sig_key
*(*md5_lookup
) (const struct sock
*sk
,
1898 const struct sock
*addr_sk
);
1899 int (*calc_md5_hash
)(char *location
,
1900 const struct tcp_md5sig_key
*md5
,
1901 const struct sock
*sk
,
1902 const struct sk_buff
*skb
);
1903 int (*md5_parse
)(struct sock
*sk
,
1905 char __user
*optval
,
1910 struct tcp_request_sock_ops
{
1912 #ifdef CONFIG_TCP_MD5SIG
1913 struct tcp_md5sig_key
*(*req_md5_lookup
)(const struct sock
*sk
,
1914 const struct sock
*addr_sk
);
1915 int (*calc_md5_hash
) (char *location
,
1916 const struct tcp_md5sig_key
*md5
,
1917 const struct sock
*sk
,
1918 const struct sk_buff
*skb
);
1920 void (*init_req
)(struct request_sock
*req
,
1921 const struct sock
*sk_listener
,
1922 struct sk_buff
*skb
);
1923 #ifdef CONFIG_SYN_COOKIES
1924 __u32 (*cookie_init_seq
)(const struct sk_buff
*skb
,
1927 struct dst_entry
*(*route_req
)(const struct sock
*sk
, struct flowi
*fl
,
1928 const struct request_sock
*req
);
1929 u32 (*init_seq
)(const struct sk_buff
*skb
);
1930 u32 (*init_ts_off
)(const struct net
*net
, const struct sk_buff
*skb
);
1931 int (*send_synack
)(const struct sock
*sk
, struct dst_entry
*dst
,
1932 struct flowi
*fl
, struct request_sock
*req
,
1933 struct tcp_fastopen_cookie
*foc
,
1934 enum tcp_synack_type synack_type
);
1937 #ifdef CONFIG_SYN_COOKIES
1938 static inline __u32
cookie_init_sequence(const struct tcp_request_sock_ops
*ops
,
1939 const struct sock
*sk
, struct sk_buff
*skb
,
1942 tcp_synq_overflow(sk
);
1943 __NET_INC_STATS(sock_net(sk
), LINUX_MIB_SYNCOOKIESSENT
);
1944 return ops
->cookie_init_seq(skb
, mss
);
1947 static inline __u32
cookie_init_sequence(const struct tcp_request_sock_ops
*ops
,
1948 const struct sock
*sk
, struct sk_buff
*skb
,
1955 int tcpv4_offload_init(void);
1957 void tcp_v4_init(void);
1958 void tcp_init(void);
1960 /* tcp_recovery.c */
1961 void tcp_mark_skb_lost(struct sock
*sk
, struct sk_buff
*skb
);
1962 void tcp_newreno_mark_lost(struct sock
*sk
, bool snd_una_advanced
);
1963 extern s32
tcp_rack_skb_timeout(struct tcp_sock
*tp
, struct sk_buff
*skb
,
1965 extern void tcp_rack_mark_lost(struct sock
*sk
);
1966 extern void tcp_rack_advance(struct tcp_sock
*tp
, u8 sacked
, u32 end_seq
,
1968 extern void tcp_rack_reo_timeout(struct sock
*sk
);
1969 extern void tcp_rack_update_reo_wnd(struct sock
*sk
, struct rate_sample
*rs
);
1971 /* At how many usecs into the future should the RTO fire? */
1972 static inline s64
tcp_rto_delta_us(const struct sock
*sk
)
1974 const struct sk_buff
*skb
= tcp_rtx_queue_head(sk
);
1975 u32 rto
= inet_csk(sk
)->icsk_rto
;
1976 u64 rto_time_stamp_us
= tcp_skb_timestamp_us(skb
) + jiffies_to_usecs(rto
);
1978 return rto_time_stamp_us
- tcp_sk(sk
)->tcp_mstamp
;
1982 * Save and compile IPv4 options, return a pointer to it
1984 static inline struct ip_options_rcu
*tcp_v4_save_options(struct net
*net
,
1985 struct sk_buff
*skb
)
1987 const struct ip_options
*opt
= &TCP_SKB_CB(skb
)->header
.h4
.opt
;
1988 struct ip_options_rcu
*dopt
= NULL
;
1991 int opt_size
= sizeof(*dopt
) + opt
->optlen
;
1993 dopt
= kmalloc(opt_size
, GFP_ATOMIC
);
1994 if (dopt
&& __ip_options_echo(net
, &dopt
->opt
, skb
, opt
)) {
2002 /* locally generated TCP pure ACKs have skb->truesize == 2
2003 * (check tcp_send_ack() in net/ipv4/tcp_output.c )
2004 * This is much faster than dissecting the packet to find out.
2005 * (Think of GRE encapsulations, IPv4, IPv6, ...)
2007 static inline bool skb_is_tcp_pure_ack(const struct sk_buff
*skb
)
2009 return skb
->truesize
== 2;
2012 static inline void skb_set_tcp_pure_ack(struct sk_buff
*skb
)
2017 static inline int tcp_inq(struct sock
*sk
)
2019 struct tcp_sock
*tp
= tcp_sk(sk
);
2022 if ((1 << sk
->sk_state
) & (TCPF_SYN_SENT
| TCPF_SYN_RECV
)) {
2024 } else if (sock_flag(sk
, SOCK_URGINLINE
) ||
2026 before(tp
->urg_seq
, tp
->copied_seq
) ||
2027 !before(tp
->urg_seq
, tp
->rcv_nxt
)) {
2029 answ
= tp
->rcv_nxt
- tp
->copied_seq
;
2031 /* Subtract 1, if FIN was received */
2032 if (answ
&& sock_flag(sk
, SOCK_DONE
))
2035 answ
= tp
->urg_seq
- tp
->copied_seq
;
2041 int tcp_peek_len(struct socket
*sock
);
2043 static inline void tcp_segs_in(struct tcp_sock
*tp
, const struct sk_buff
*skb
)
2047 segs_in
= max_t(u16
, 1, skb_shinfo(skb
)->gso_segs
);
2048 tp
->segs_in
+= segs_in
;
2049 if (skb
->len
> tcp_hdrlen(skb
))
2050 tp
->data_segs_in
+= segs_in
;
2054 * TCP listen path runs lockless.
2055 * We forced "struct sock" to be const qualified to make sure
2056 * we don't modify one of its field by mistake.
2057 * Here, we increment sk_drops which is an atomic_t, so we can safely
2058 * make sock writable again.
2060 static inline void tcp_listendrop(const struct sock
*sk
)
2062 atomic_inc(&((struct sock
*)sk
)->sk_drops
);
2063 __NET_INC_STATS(sock_net(sk
), LINUX_MIB_LISTENDROPS
);
2066 enum hrtimer_restart
tcp_pace_kick(struct hrtimer
*timer
);
2069 * Interface for adding Upper Level Protocols over TCP
2072 #define TCP_ULP_NAME_MAX 16
2073 #define TCP_ULP_MAX 128
2074 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX)
2076 struct tcp_ulp_ops
{
2077 struct list_head list
;
2079 /* initialize ulp */
2080 int (*init
)(struct sock
*sk
);
2082 void (*release
)(struct sock
*sk
);
2084 char name
[TCP_ULP_NAME_MAX
];
2085 struct module
*owner
;
2087 int tcp_register_ulp(struct tcp_ulp_ops
*type
);
2088 void tcp_unregister_ulp(struct tcp_ulp_ops
*type
);
2089 int tcp_set_ulp(struct sock
*sk
, const char *name
);
2090 void tcp_get_available_ulp(char *buf
, size_t len
);
2091 void tcp_cleanup_ulp(struct sock
*sk
);
2093 #define MODULE_ALIAS_TCP_ULP(name) \
2094 __MODULE_INFO(alias, alias_userspace, name); \
2095 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name)
2100 int tcp_bpf_init(struct sock
*sk
);
2101 void tcp_bpf_reinit(struct sock
*sk
);
2102 int tcp_bpf_sendmsg_redir(struct sock
*sk
, struct sk_msg
*msg
, u32 bytes
,
2104 int tcp_bpf_recvmsg(struct sock
*sk
, struct msghdr
*msg
, size_t len
,
2105 int nonblock
, int flags
, int *addr_len
);
2106 int __tcp_bpf_recvmsg(struct sock
*sk
, struct sk_psock
*psock
,
2107 struct msghdr
*msg
, int len
, int flags
);
2109 /* Call BPF_SOCK_OPS program that returns an int. If the return value
2110 * is < 0, then the BPF op failed (for example if the loaded BPF
2111 * program does not support the chosen operation or there is no BPF
2115 static inline int tcp_call_bpf(struct sock
*sk
, int op
, u32 nargs
, u32
*args
)
2117 struct bpf_sock_ops_kern sock_ops
;
2120 memset(&sock_ops
, 0, offsetof(struct bpf_sock_ops_kern
, temp
));
2121 if (sk_fullsock(sk
)) {
2122 sock_ops
.is_fullsock
= 1;
2123 sock_owned_by_me(sk
);
2129 memcpy(sock_ops
.args
, args
, nargs
* sizeof(*args
));
2131 ret
= BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops
);
2133 ret
= sock_ops
.reply
;
2139 static inline int tcp_call_bpf_2arg(struct sock
*sk
, int op
, u32 arg1
, u32 arg2
)
2141 u32 args
[2] = {arg1
, arg2
};
2143 return tcp_call_bpf(sk
, op
, 2, args
);
2146 static inline int tcp_call_bpf_3arg(struct sock
*sk
, int op
, u32 arg1
, u32 arg2
,
2149 u32 args
[3] = {arg1
, arg2
, arg3
};
2151 return tcp_call_bpf(sk
, op
, 3, args
);
2155 static inline int tcp_call_bpf(struct sock
*sk
, int op
, u32 nargs
, u32
*args
)
2160 static inline int tcp_call_bpf_2arg(struct sock
*sk
, int op
, u32 arg1
, u32 arg2
)
2165 static inline int tcp_call_bpf_3arg(struct sock
*sk
, int op
, u32 arg1
, u32 arg2
,
2173 static inline u32
tcp_timeout_init(struct sock
*sk
)
2177 timeout
= tcp_call_bpf(sk
, BPF_SOCK_OPS_TIMEOUT_INIT
, 0, NULL
);
2180 timeout
= TCP_TIMEOUT_INIT
;
2184 static inline u32
tcp_rwnd_init_bpf(struct sock
*sk
)
2188 rwnd
= tcp_call_bpf(sk
, BPF_SOCK_OPS_RWND_INIT
, 0, NULL
);
2195 static inline bool tcp_bpf_ca_needs_ecn(struct sock
*sk
)
2197 return (tcp_call_bpf(sk
, BPF_SOCK_OPS_NEEDS_ECN
, 0, NULL
) == 1);
2200 #if IS_ENABLED(CONFIG_SMC)
2201 extern struct static_key_false tcp_have_smc
;
2204 #if IS_ENABLED(CONFIG_TLS_DEVICE)
2205 void clean_acked_data_enable(struct inet_connection_sock
*icsk
,
2206 void (*cad
)(struct sock
*sk
, u32 ack_seq
));
2207 void clean_acked_data_disable(struct inet_connection_sock
*icsk
);