1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the TCP module.
8 *
9 * Version: @(#)tcp.h 1.0.5 05/23/93
10 *
11 * Authors: Ross Biro
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 */
14 #ifndef _TCP_H
15 #define _TCP_H
16
17 #define FASTRETRANS_DEBUG 1
18
19 #include <linux/list.h>
20 #include <linux/tcp.h>
21 #include <linux/bug.h>
22 #include <linux/slab.h>
23 #include <linux/cache.h>
24 #include <linux/percpu.h>
25 #include <linux/skbuff.h>
26 #include <linux/kref.h>
27 #include <linux/ktime.h>
28 #include <linux/indirect_call_wrapper.h>
29
30 #include <net/inet_connection_sock.h>
31 #include <net/inet_timewait_sock.h>
32 #include <net/inet_hashtables.h>
33 #include <net/checksum.h>
34 #include <net/request_sock.h>
35 #include <net/sock_reuseport.h>
36 #include <net/sock.h>
37 #include <net/snmp.h>
38 #include <net/ip.h>
39 #include <net/tcp_states.h>
40 #include <net/inet_ecn.h>
41 #include <net/dst.h>
42 #include <net/mptcp.h>
43 #ifdef CONFIG_NEWIP
44 #include <linux/nip.h> /* NIP */
45 #endif
46 #include <linux/seq_file.h>
47 #include <linux/memcontrol.h>
48 #include <linux/bpf-cgroup.h>
49 #include <linux/siphash.h>
50
51 extern struct inet_hashinfo tcp_hashinfo;
52
53 DECLARE_PER_CPU(unsigned int, tcp_orphan_count);
54 int tcp_orphan_count_sum(void);
55
56 void tcp_time_wait(struct sock *sk, int state, int timeo);
57
58 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER)
59 #define MAX_TCP_OPTION_SPACE 40
60 #define TCP_MIN_SND_MSS 48
61 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
62
63 /*
64 * Never offer a window over 32767 without using window scaling. Some
65 * poor stacks do signed 16bit maths!
66 */
67 #define MAX_TCP_WINDOW 32767U
68
69 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
70 #define TCP_MIN_MSS 88U
71
72 /* The initial MTU to use for probing */
73 #define TCP_BASE_MSS 1024
74
75 /* probing interval, default to 10 minutes as per RFC4821 */
76 #define TCP_PROBE_INTERVAL 600
77
78 /* Specify interval when tcp mtu probing will stop */
79 #define TCP_PROBE_THRESHOLD 8
80
81 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
82 #define TCP_FASTRETRANS_THRESH 3
83
84 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
85 #define TCP_MAX_QUICKACKS 16U
86
87 /* Maximal number of window scale according to RFC1323 */
88 #define TCP_MAX_WSCALE 14U
89
90 /* urg_data states */
91 #define TCP_URG_VALID 0x0100
92 #define TCP_URG_NOTYET 0x0200
93 #define TCP_URG_READ 0x0400
94
95 #define TCP_RETR1 3 /*
96 * This is how many retries it does before it
97 * tries to figure out if the gateway is
98 * down. Minimal RFC value is 3; it corresponds
99 * to ~3sec-8min depending on RTO.
100 */
101
102 #define TCP_RETR2 15 /*
103 * This should take at least
104 * 90 minutes to time out.
105 * RFC1122 says that the limit is 100 sec.
106 * 15 is ~13-30min depending on RTO.
107 */
108
109 #define TCP_SYN_RETRIES 6 /* This is how many retries are done
110 * when active opening a connection.
111 * RFC1122 says the minimum retry MUST
112 * be at least 180secs. Nevertheless
113 * this value is corresponding to
114 * 63secs of retransmission with the
115 * current initial RTO.
116 */
117
118 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done
119 * when passive opening a connection.
120 * This is corresponding to 31secs of
121 * retransmission with the current
122 * initial RTO.
123 */
124
125 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
126 * state, about 60 seconds */
127 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
128 /* BSD style FIN_WAIT2 deadlock breaker.
129 * It used to be 3min, new value is 60sec,
130 * to combine FIN-WAIT-2 timeout with
131 * TIME-WAIT timer.
132 */
133 #define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */
134
135 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
136 #if HZ >= 100
137 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
138 #define TCP_ATO_MIN ((unsigned)(HZ/25))
139 #else
140 #define TCP_DELACK_MIN 4U
141 #define TCP_ATO_MIN 4U
142 #endif
143 #define TCP_RTO_MAX ((unsigned)(120*HZ))
144 #define TCP_RTO_MIN ((unsigned)(HZ/5))
145 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */
146
147 #define TCP_TIMEOUT_MIN_US (2*USEC_PER_MSEC) /* Min TCP timeout in microsecs */
148
149 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */
150 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now
151 * used as a fallback RTO for the
152 * initial data transmission if no
153 * valid RTT sample has been acquired,
154 * most likely due to retrans in 3WHS.
155 */
156
157 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
158 * for local resources.
159 */
160 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
161 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
162 #define TCP_KEEPALIVE_INTVL (75*HZ)
163
164 #define MAX_TCP_KEEPIDLE 32767
165 #define MAX_TCP_KEEPINTVL 32767
166 #define MAX_TCP_KEEPCNT 127
167 #define MAX_TCP_SYNCNT 127
168
169 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
170
171 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
172 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
173 * after this time. It should be equal
174 * (or greater than) TCP_TIMEWAIT_LEN
175 * to provide reliability equal to one
176 * provided by timewait state.
177 */
178 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
179 * timestamps. It must be less than
180 * minimal timewait lifetime.
181 */
182 /*
183 * TCP option
184 */
185
186 #define TCPOPT_NOP 1 /* Padding */
187 #define TCPOPT_EOL 0 /* End of options */
188 #define TCPOPT_MSS 2 /* Segment size negotiating */
189 #define TCPOPT_WINDOW 3 /* Window scaling */
190 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
191 #define TCPOPT_SACK 5 /* SACK Block */
192 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
193 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
194 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */
195 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
196 #define TCPOPT_EXP 254 /* Experimental */
197 /* Magic number to be after the option value for sharing TCP
198 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
199 */
200 #define TCPOPT_FASTOPEN_MAGIC 0xF989
201 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9
202
203 /*
204 * TCP option lengths
205 */
206
207 #define TCPOLEN_MSS 4
208 #define TCPOLEN_WINDOW 3
209 #define TCPOLEN_SACK_PERM 2
210 #define TCPOLEN_TIMESTAMP 10
211 #define TCPOLEN_MD5SIG 18
212 #define TCPOLEN_FASTOPEN_BASE 2
213 #define TCPOLEN_EXP_FASTOPEN_BASE 4
214 #define TCPOLEN_EXP_SMC_BASE 6
215
216 /* But this is what stacks really send out. */
217 #define TCPOLEN_TSTAMP_ALIGNED 12
218 #define TCPOLEN_WSCALE_ALIGNED 4
219 #define TCPOLEN_SACKPERM_ALIGNED 4
220 #define TCPOLEN_SACK_BASE 2
221 #define TCPOLEN_SACK_BASE_ALIGNED 4
222 #define TCPOLEN_SACK_PERBLOCK 8
223 #define TCPOLEN_MD5SIG_ALIGNED 20
224 #define TCPOLEN_MSS_ALIGNED 4
225 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8
226
227 /* Flags in tp->nonagle */
228 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
229 #define TCP_NAGLE_CORK 2 /* Socket is corked */
230 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
231
232 /* TCP thin-stream limits */
233 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
234
235 /* TCP initial congestion window as per rfc6928 */
236 #define TCP_INIT_CWND 10
237
238 /* Bit Flags for sysctl_tcp_fastopen */
239 #define TFO_CLIENT_ENABLE 1
240 #define TFO_SERVER_ENABLE 2
241 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */
242
243 /* Accept SYN data w/o any cookie option */
244 #define TFO_SERVER_COOKIE_NOT_REQD 0x200
245
246 /* Force enable TFO on all listeners, i.e., not requiring the
247 * TCP_FASTOPEN socket option.
248 */
249 #define TFO_SERVER_WO_SOCKOPT1 0x400
250
251
252 /* sysctl variables for tcp */
253 extern int sysctl_tcp_max_orphans;
254 extern long sysctl_tcp_mem[3];
255
256 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */
257 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */
258 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */
259
260 extern atomic_long_t tcp_memory_allocated;
261 extern struct percpu_counter tcp_sockets_allocated;
262 extern unsigned long tcp_memory_pressure;
263
264 /* optimized version of sk_under_memory_pressure() for TCP sockets */
tcp_under_memory_pressure(const struct sock *sk)265 static inline bool tcp_under_memory_pressure(const struct sock *sk)
266 {
267 if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
268 mem_cgroup_under_socket_pressure(sk->sk_memcg))
269 return true;
270
271 return READ_ONCE(tcp_memory_pressure);
272 }
273 /*
274 * The next routines deal with comparing 32 bit unsigned ints
275 * and worry about wraparound (automatic with unsigned arithmetic).
276 */
277
before(__u32 seq1, __u32 seq2)278 static inline bool before(__u32 seq1, __u32 seq2)
279 {
280 return (__s32)(seq1-seq2) < 0;
281 }
282 #define after(seq2, seq1) before(seq1, seq2)
283
284 /* is s2<=s1<=s3 ? */
between(__u32 seq1, __u32 seq2, __u32 seq3)285 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3)
286 {
287 return seq3 - seq2 >= seq1 - seq2;
288 }
289
tcp_out_of_memory(struct sock *sk)290 static inline bool tcp_out_of_memory(struct sock *sk)
291 {
292 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
293 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
294 return true;
295 return false;
296 }
297
298 void sk_forced_mem_schedule(struct sock *sk, int size);
299
300 bool tcp_check_oom(struct sock *sk, int shift);
301
302
303 extern struct proto tcp_prot;
304
305 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
306 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field)
307 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
308 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
309
310 void tcp_tasklet_init(void);
311
312 int tcp_v4_err(struct sk_buff *skb, u32);
313
314 void tcp_shutdown(struct sock *sk, int how);
315
316 int tcp_v4_early_demux(struct sk_buff *skb);
317 int tcp_v4_rcv(struct sk_buff *skb);
318
319 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
320 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
321 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size);
322 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size,
323 int flags);
324 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset,
325 size_t size, int flags);
326 ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
327 size_t size, int flags);
328 int tcp_send_mss(struct sock *sk, int *size_goal, int flags);
329 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle,
330 int size_goal);
331 void tcp_release_cb(struct sock *sk);
332 void tcp_wfree(struct sk_buff *skb);
333 void tcp_write_timer_handler(struct sock *sk);
334 void tcp_delack_timer_handler(struct sock *sk);
335 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
336 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
337 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb);
338 void tcp_rcv_space_adjust(struct sock *sk);
339 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp);
340 void tcp_twsk_destructor(struct sock *sk);
341 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
342 struct pipe_inode_info *pipe, size_t len,
343 unsigned int flags);
344
tcp_dec_quickack_mode(struct sock *sk)345 static inline void tcp_dec_quickack_mode(struct sock *sk)
346 {
347 struct inet_connection_sock *icsk = inet_csk(sk);
348
349 if (icsk->icsk_ack.quick) {
350 /* How many ACKs S/ACKing new data have we sent? */
351 const unsigned int pkts = inet_csk_ack_scheduled(sk) ? 1 : 0;
352
353 if (pkts >= icsk->icsk_ack.quick) {
354 icsk->icsk_ack.quick = 0;
355 /* Leaving quickack mode we deflate ATO. */
356 icsk->icsk_ack.ato = TCP_ATO_MIN;
357 } else
358 icsk->icsk_ack.quick -= pkts;
359 }
360 }
361
362 #define TCP_ECN_OK 1
363 #define TCP_ECN_QUEUE_CWR 2
364 #define TCP_ECN_DEMAND_CWR 4
365 #define TCP_ECN_SEEN 8
366
367 enum tcp_tw_status {
368 TCP_TW_SUCCESS = 0,
369 TCP_TW_RST = 1,
370 TCP_TW_ACK = 2,
371 TCP_TW_SYN = 3
372 };
373
374
375 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
376 struct sk_buff *skb,
377 const struct tcphdr *th);
378 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
379 struct request_sock *req, bool fastopen,
380 bool *lost_race);
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_close(struct sock *sk, long timeout);
392 void tcp_init_sock(struct sock *sk);
393 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb);
394 __poll_t tcp_poll(struct file *file, struct socket *sock,
395 struct poll_table_struct *wait);
396 int tcp_getsockopt(struct sock *sk, int level, int optname,
397 char __user *optval, int __user *optlen);
398 bool tcp_bpf_bypass_getsockopt(int level, int optname);
399 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
400 unsigned int optlen);
401 void tcp_set_keepalive(struct sock *sk, int val);
402 void tcp_syn_ack_timeout(const struct request_sock *req);
403 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
404 int flags, int *addr_len);
405 int tcp_set_rcvlowat(struct sock *sk, int val);
406 void tcp_data_ready(struct sock *sk);
407 #ifdef CONFIG_MMU
408 int tcp_mmap(struct file *file, struct socket *sock,
409 struct vm_area_struct *vma);
410 #endif
411 void tcp_parse_options(const struct net *net, const struct sk_buff *skb,
412 struct tcp_options_received *opt_rx,
413 int estab, struct tcp_fastopen_cookie *foc);
414 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
415
416 /*
417 * BPF SKB-less helpers
418 */
419 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
420 struct tcphdr *th, u32 *cookie);
421 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph,
422 struct tcphdr *th, u32 *cookie);
423 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops,
424 const struct tcp_request_sock_ops *af_ops,
425 struct sock *sk, struct tcphdr *th);
426 /*
427 * TCP v4 functions exported for the inet6 API
428 */
429
430 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
431 void tcp_v4_mtu_reduced(struct sock *sk);
432 void tcp_req_err(struct sock *sk, u32 seq, bool abort);
433 void tcp_ld_RTO_revert(struct sock *sk, u32 seq);
434 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
435 struct sock *tcp_create_openreq_child(const struct sock *sk,
436 struct request_sock *req,
437 struct sk_buff *skb);
438 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst);
439 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
440 struct request_sock *req,
441 struct dst_entry *dst,
442 struct request_sock *req_unhash,
443 bool *own_req);
444 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
445 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
446 int tcp_connect(struct sock *sk);
447 enum tcp_synack_type {
448 TCP_SYNACK_NORMAL,
449 TCP_SYNACK_FASTOPEN,
450 TCP_SYNACK_COOKIE,
451 };
452 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
453 struct request_sock *req,
454 struct tcp_fastopen_cookie *foc,
455 enum tcp_synack_type synack_type,
456 struct sk_buff *syn_skb);
457 int tcp_disconnect(struct sock *sk, int flags);
458
459 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb);
460 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size);
461 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
462
463 /* From syncookies.c */
464 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
465 struct request_sock *req,
466 struct dst_entry *dst, u32 tsoff);
467 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th,
468 u32 cookie);
469 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb);
470 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
471 const struct tcp_request_sock_ops *af_ops,
472 struct sock *sk, struct sk_buff *skb);
473 #ifdef CONFIG_SYN_COOKIES
474
475 /* Syncookies use a monotonic timer which increments every 60 seconds.
476 * This counter is used both as a hash input and partially encoded into
477 * the cookie value. A cookie is only validated further if the delta
478 * between the current counter value and the encoded one is less than this,
479 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if
480 * the counter advances immediately after a cookie is generated).
481 */
482 #define MAX_SYNCOOKIE_AGE 2
483 #define TCP_SYNCOOKIE_PERIOD (60 * HZ)
484 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD)
485
486 /* syncookies: remember time of last synqueue overflow
487 * But do not dirty this field too often (once per second is enough)
488 * It is racy as we do not hold a lock, but race is very minor.
489 */
tcp_synq_overflow(const struct sock *sk)490 static inline void tcp_synq_overflow(const struct sock *sk)
491 {
492 unsigned int last_overflow;
493 unsigned int now = jiffies;
494
495 if (sk->sk_reuseport) {
496 struct sock_reuseport *reuse;
497
498 reuse = rcu_dereference(sk->sk_reuseport_cb);
499 if (likely(reuse)) {
500 last_overflow = READ_ONCE(reuse->synq_overflow_ts);
501 if (!time_between32(now, last_overflow,
502 last_overflow + HZ))
503 WRITE_ONCE(reuse->synq_overflow_ts, now);
504 return;
505 }
506 }
507
508 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp);
509 if (!time_between32(now, last_overflow, last_overflow + HZ))
510 WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now);
511 }
512
513 /* syncookies: no recent synqueue overflow on this listening socket? */
tcp_synq_no_recent_overflow(const struct sock *sk)514 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk)
515 {
516 unsigned int last_overflow;
517 unsigned int now = jiffies;
518
519 if (sk->sk_reuseport) {
520 struct sock_reuseport *reuse;
521
522 reuse = rcu_dereference(sk->sk_reuseport_cb);
523 if (likely(reuse)) {
524 last_overflow = READ_ONCE(reuse->synq_overflow_ts);
525 return !time_between32(now, last_overflow - HZ,
526 last_overflow +
527 TCP_SYNCOOKIE_VALID);
528 }
529 }
530
531 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp);
532
533 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID,
534 * then we're under synflood. However, we have to use
535 * 'last_overflow - HZ' as lower bound. That's because a concurrent
536 * tcp_synq_overflow() could update .ts_recent_stamp after we read
537 * jiffies but before we store .ts_recent_stamp into last_overflow,
538 * which could lead to rejecting a valid syncookie.
539 */
540 return !time_between32(now, last_overflow - HZ,
541 last_overflow + TCP_SYNCOOKIE_VALID);
542 }
543
tcp_cookie_time(void)544 static inline u32 tcp_cookie_time(void)
545 {
546 u64 val = get_jiffies_64();
547
548 do_div(val, TCP_SYNCOOKIE_PERIOD);
549 return val;
550 }
551
552 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
553 u16 *mssp);
554 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
555 u64 cookie_init_timestamp(struct request_sock *req, u64 now);
556 bool cookie_timestamp_decode(const struct net *net,
557 struct tcp_options_received *opt);
558 bool cookie_ecn_ok(const struct tcp_options_received *opt,
559 const struct net *net, const struct dst_entry *dst);
560
561 /* From net/ipv6/syncookies.c */
562 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
563 u32 cookie);
564 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
565
566 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
567 const struct tcphdr *th, u16 *mssp);
568 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss);
569 #endif
570 /* tcp_output.c */
571
572 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
573 int nonagle);
574 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
575 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
576 void tcp_retransmit_timer(struct sock *sk);
577 void tcp_xmit_retransmit_queue(struct sock *);
578 void tcp_simple_retransmit(struct sock *);
579 void tcp_enter_recovery(struct sock *sk, bool ece_ack);
580 int tcp_trim_head(struct sock *, struct sk_buff *, u32);
581 enum tcp_queue {
582 TCP_FRAG_IN_WRITE_QUEUE,
583 TCP_FRAG_IN_RTX_QUEUE,
584 };
585 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
586 struct sk_buff *skb, u32 len,
587 unsigned int mss_now, gfp_t gfp);
588
589 void tcp_send_probe0(struct sock *);
590 void tcp_send_partial(struct sock *);
591 int tcp_write_wakeup(struct sock *, int mib);
592 void tcp_send_fin(struct sock *sk);
593 void tcp_send_active_reset(struct sock *sk, gfp_t priority);
594 int tcp_send_synack(struct sock *);
595 void tcp_push_one(struct sock *, unsigned int mss_now);
596 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt);
597 void tcp_send_ack(struct sock *sk);
598 void tcp_send_delayed_ack(struct sock *sk);
599 void tcp_send_loss_probe(struct sock *sk);
600 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto);
601 void tcp_skb_collapse_tstamp(struct sk_buff *skb,
602 const struct sk_buff *next_skb);
603
604 /* tcp_input.c */
605 void tcp_rearm_rto(struct sock *sk);
606 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req);
607 void tcp_reset(struct sock *sk);
608 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb);
609 void tcp_fin(struct sock *sk);
610 void tcp_check_space(struct sock *sk);
611
612 /* tcp_timer.c */
613 void tcp_init_xmit_timers(struct sock *);
tcp_clear_xmit_timers(struct sock *sk)614 static inline void tcp_clear_xmit_timers(struct sock *sk)
615 {
616 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1)
617 __sock_put(sk);
618
619 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1)
620 __sock_put(sk);
621
622 inet_csk_clear_xmit_timers(sk);
623 }
624
625 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
626 unsigned int tcp_current_mss(struct sock *sk);
627 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when);
628
629 /* Bound MSS / TSO packet size with the half of the window */
tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)630 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
631 {
632 int cutoff;
633
634 /* When peer uses tiny windows, there is no use in packetizing
635 * to sub-MSS pieces for the sake of SWS or making sure there
636 * are enough packets in the pipe for fast recovery.
637 *
638 * On the other hand, for extremely large MSS devices, handling
639 * smaller than MSS windows in this way does make sense.
640 */
641 if (tp->max_window > TCP_MSS_DEFAULT)
642 cutoff = (tp->max_window >> 1);
643 else
644 cutoff = tp->max_window;
645
646 if (cutoff && pktsize > cutoff)
647 return max_t(int, cutoff, 68U - tp->tcp_header_len);
648 else
649 return pktsize;
650 }
651
652 /* tcp.c */
653 void tcp_get_info(struct sock *, struct tcp_info *);
654
655 /* Read 'sendfile()'-style from a TCP socket */
656 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
657 sk_read_actor_t recv_actor);
658
659 void tcp_initialize_rcv_mss(struct sock *sk);
660
661 int tcp_mtu_to_mss(struct sock *sk, int pmtu);
662 int tcp_mss_to_mtu(struct sock *sk, int mss);
663 void tcp_mtup_init(struct sock *sk);
664
tcp_bound_rto(const struct sock *sk)665 static inline void tcp_bound_rto(const struct sock *sk)
666 {
667 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
668 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
669 }
670
__tcp_set_rto(const struct tcp_sock *tp)671 static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
672 {
673 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us);
674 }
675
__tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)676 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
677 {
678 /* mptcp hooks are only on the slow path */
679 if (sk_is_mptcp((struct sock *)tp))
680 return;
681
682 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
683 ntohl(TCP_FLAG_ACK) |
684 snd_wnd);
685 }
686
tcp_fast_path_on(struct tcp_sock *tp)687 static inline void tcp_fast_path_on(struct tcp_sock *tp)
688 {
689 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
690 }
691
tcp_fast_path_check(struct sock *sk)692 static inline void tcp_fast_path_check(struct sock *sk)
693 {
694 struct tcp_sock *tp = tcp_sk(sk);
695
696 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) &&
697 tp->rcv_wnd &&
698 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
699 !tp->urg_data)
700 tcp_fast_path_on(tp);
701 }
702
703 /* Compute the actual rto_min value */
tcp_rto_min(struct sock *sk)704 static inline u32 tcp_rto_min(struct sock *sk)
705 {
706 const struct dst_entry *dst = __sk_dst_get(sk);
707 u32 rto_min = inet_csk(sk)->icsk_rto_min;
708
709 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
710 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
711 return rto_min;
712 }
713
tcp_rto_min_us(struct sock *sk)714 static inline u32 tcp_rto_min_us(struct sock *sk)
715 {
716 return jiffies_to_usecs(tcp_rto_min(sk));
717 }
718
tcp_ca_dst_locked(const struct dst_entry *dst)719 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst)
720 {
721 return dst_metric_locked(dst, RTAX_CC_ALGO);
722 }
723
724 /* Minimum RTT in usec. ~0 means not available. */
tcp_min_rtt(const struct tcp_sock *tp)725 static inline u32 tcp_min_rtt(const struct tcp_sock *tp)
726 {
727 return minmax_get(&tp->rtt_min);
728 }
729
730 /* Compute the actual receive window we are currently advertising.
731 * Rcv_nxt can be after the window if our peer push more data
732 * than the offered window.
733 */
tcp_receive_window(const struct tcp_sock *tp)734 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
735 {
736 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
737
738 if (win < 0)
739 win = 0;
740 return (u32) win;
741 }
742
743 /* Choose a new window, without checks for shrinking, and without
744 * scaling applied to the result. The caller does these things
745 * if necessary. This is a "raw" window selection.
746 */
747 u32 __tcp_select_window(struct sock *sk);
748
749 void tcp_send_window_probe(struct sock *sk);
750
751 /* TCP uses 32bit jiffies to save some space.
752 * Note that this is different from tcp_time_stamp, which
753 * historically has been the same until linux-4.13.
754 */
755 #define tcp_jiffies32 ((u32)jiffies)
756
757 /*
758 * Deliver a 32bit value for TCP timestamp option (RFC 7323)
759 * It is no longer tied to jiffies, but to 1 ms clock.
760 * Note: double check if you want to use tcp_jiffies32 instead of this.
761 */
762 #define TCP_TS_HZ 1000
763
tcp_clock_ns(void)764 static inline u64 tcp_clock_ns(void)
765 {
766 return ktime_get_ns();
767 }
768
tcp_clock_us(void)769 static inline u64 tcp_clock_us(void)
770 {
771 return div_u64(tcp_clock_ns(), NSEC_PER_USEC);
772 }
773
774 /* This should only be used in contexts where tp->tcp_mstamp is up to date */
tcp_time_stamp(const struct tcp_sock *tp)775 static inline u32 tcp_time_stamp(const struct tcp_sock *tp)
776 {
777 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ);
778 }
779
780 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */
tcp_ns_to_ts(u64 ns)781 static inline u64 tcp_ns_to_ts(u64 ns)
782 {
783 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ);
784 }
785
786 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */
tcp_time_stamp_raw(void)787 static inline u32 tcp_time_stamp_raw(void)
788 {
789 return tcp_ns_to_ts(tcp_clock_ns());
790 }
791
792 void tcp_mstamp_refresh(struct tcp_sock *tp);
793
tcp_stamp_us_delta(u64 t1, u64 t0)794 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0)
795 {
796 return max_t(s64, t1 - t0, 0);
797 }
798
tcp_skb_timestamp(const struct sk_buff *skb)799 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
800 {
801 return tcp_ns_to_ts(skb->skb_mstamp_ns);
802 }
803
804 /* provide the departure time in us unit */
tcp_skb_timestamp_us(const struct sk_buff *skb)805 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb)
806 {
807 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC);
808 }
809
810
811 #define tcp_flag_byte(th) (((u_int8_t *)th)[13])
812
813 #define TCPHDR_FIN 0x01
814 #define TCPHDR_SYN 0x02
815 #define TCPHDR_RST 0x04
816 #define TCPHDR_PSH 0x08
817 #define TCPHDR_ACK 0x10
818 #define TCPHDR_URG 0x20
819 #define TCPHDR_ECE 0x40
820 #define TCPHDR_CWR 0x80
821
822 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR)
823
824 /* This is what the send packet queuing engine uses to pass
825 * TCP per-packet control information to the transmission code.
826 * We also store the host-order sequence numbers in here too.
827 * This is 44 bytes if IPV6 is enabled.
828 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
829 */
830 struct tcp_skb_cb {
831 __u32 seq; /* Starting sequence number */
832 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
833 union {
834 /* Note : tcp_tw_isn is used in input path only
835 * (isn chosen by tcp_timewait_state_process())
836 *
837 * tcp_gso_segs/size are used in write queue only,
838 * cf tcp_skb_pcount()/tcp_skb_mss()
839 */
840 __u32 tcp_tw_isn;
841 struct {
842 u16 tcp_gso_segs;
843 u16 tcp_gso_size;
844 };
845 };
846 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */
847
848 __u8 sacked; /* State flags for SACK. */
849 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
850 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
851 #define TCPCB_LOST 0x04 /* SKB is lost */
852 #define TCPCB_TAGBITS 0x07 /* All tag bits */
853 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */
854 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
855 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
856 TCPCB_REPAIRED)
857
858 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */
859 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */
860 eor:1, /* Is skb MSG_EOR marked? */
861 has_rxtstamp:1, /* SKB has a RX timestamp */
862 unused:5;
863 __u32 ack_seq; /* Sequence number ACK'd */
864 union {
865 struct {
866 /* There is space for up to 24 bytes */
867 __u32 in_flight:30,/* Bytes in flight at transmit */
868 is_app_limited:1, /* cwnd not fully used? */
869 unused:1;
870 /* pkts S/ACKed so far upon tx of skb, incl retrans: */
871 __u32 delivered;
872 /* start of send pipeline phase */
873 u64 first_tx_mstamp;
874 /* when we reached the "delivered" count */
875 u64 delivered_mstamp;
876 } tx; /* only used for outgoing skbs */
877 union {
878 struct inet_skb_parm h4;
879 #if IS_ENABLED(CONFIG_IPV6)
880 struct inet6_skb_parm h6;
881 #endif
882 #if IS_ENABLED(CONFIG_NEWIP)
883 struct ninet_skb_parm hnip; /* NIP */
884 #endif
885 } header; /* For incoming skbs */
886 struct {
887 __u32 flags;
888 struct sock *sk_redir;
889 void *data_end;
890 } bpf;
891 };
892 };
893
894 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
895
bpf_compute_data_end_sk_skb(struct sk_buff *skb)896 static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb)
897 {
898 TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb);
899 }
900
tcp_skb_bpf_ingress(const struct sk_buff *skb)901 static inline bool tcp_skb_bpf_ingress(const struct sk_buff *skb)
902 {
903 return TCP_SKB_CB(skb)->bpf.flags & BPF_F_INGRESS;
904 }
905
tcp_skb_bpf_redirect_fetch(struct sk_buff *skb)906 static inline struct sock *tcp_skb_bpf_redirect_fetch(struct sk_buff *skb)
907 {
908 return TCP_SKB_CB(skb)->bpf.sk_redir;
909 }
910
tcp_skb_bpf_redirect_clear(struct sk_buff *skb)911 static inline void tcp_skb_bpf_redirect_clear(struct sk_buff *skb)
912 {
913 TCP_SKB_CB(skb)->bpf.sk_redir = NULL;
914 }
915
916 extern const struct inet_connection_sock_af_ops ipv4_specific;
917
918 #if IS_ENABLED(CONFIG_IPV6)
919 /* This is the variant of inet6_iif() that must be used by TCP,
920 * as TCP moves IP6CB into a different location in skb->cb[]
921 */
tcp_v6_iif(const struct sk_buff *skb)922 static inline int tcp_v6_iif(const struct sk_buff *skb)
923 {
924 return TCP_SKB_CB(skb)->header.h6.iif;
925 }
926
tcp_v6_iif_l3_slave(const struct sk_buff *skb)927 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb)
928 {
929 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
930
931 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif;
932 }
933
934 /* TCP_SKB_CB reference means this can not be used from early demux */
tcp_v6_sdif(const struct sk_buff *skb)935 static inline int tcp_v6_sdif(const struct sk_buff *skb)
936 {
937 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
938 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags))
939 return TCP_SKB_CB(skb)->header.h6.iif;
940 #endif
941 return 0;
942 }
943
944 extern const struct inet_connection_sock_af_ops ipv6_specific;
945
946 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb));
947 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb));
948 void tcp_v6_early_demux(struct sk_buff *skb);
949
950 #endif
951
952 /* TCP_SKB_CB reference means this can not be used from early demux */
tcp_v4_sdif(struct sk_buff *skb)953 static inline int tcp_v4_sdif(struct sk_buff *skb)
954 {
955 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
956 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
957 return TCP_SKB_CB(skb)->header.h4.iif;
958 #endif
959 return 0;
960 }
961
962 /* Due to TSO, an SKB can be composed of multiple actual
963 * packets. To keep these tracked properly, we use this.
964 */
tcp_skb_pcount(const struct sk_buff *skb)965 static inline int tcp_skb_pcount(const struct sk_buff *skb)
966 {
967 return TCP_SKB_CB(skb)->tcp_gso_segs;
968 }
969
tcp_skb_pcount_set(struct sk_buff *skb, int segs)970 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs)
971 {
972 TCP_SKB_CB(skb)->tcp_gso_segs = segs;
973 }
974
tcp_skb_pcount_add(struct sk_buff *skb, int segs)975 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs)
976 {
977 TCP_SKB_CB(skb)->tcp_gso_segs += segs;
978 }
979
980 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
tcp_skb_mss(const struct sk_buff *skb)981 static inline int tcp_skb_mss(const struct sk_buff *skb)
982 {
983 return TCP_SKB_CB(skb)->tcp_gso_size;
984 }
985
tcp_skb_can_collapse_to(const struct sk_buff *skb)986 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb)
987 {
988 return likely(!TCP_SKB_CB(skb)->eor);
989 }
990
tcp_skb_can_collapse(const struct sk_buff *to, const struct sk_buff *from)991 static inline bool tcp_skb_can_collapse(const struct sk_buff *to,
992 const struct sk_buff *from)
993 {
994 return likely(tcp_skb_can_collapse_to(to) &&
995 mptcp_skb_can_collapse(to, from));
996 }
997
998 /* Events passed to congestion control interface */
999 enum tcp_ca_event {
1000 CA_EVENT_TX_START, /* first transmit when no packets in flight */
1001 CA_EVENT_CWND_RESTART, /* congestion window restart */
1002 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
1003 CA_EVENT_LOSS, /* loss timeout */
1004 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */
1005 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */
1006 };
1007
1008 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */
1009 enum tcp_ca_ack_event_flags {
1010 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */
1011 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */
1012 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */
1013 };
1014
1015 /*
1016 * Interface for adding new TCP congestion control handlers
1017 */
1018 #define TCP_CA_NAME_MAX 16
1019 #define TCP_CA_MAX 128
1020 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
1021
1022 #define TCP_CA_UNSPEC 0
1023
1024 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */
1025 #define TCP_CONG_NON_RESTRICTED 0x1
1026 /* Requires ECN/ECT set on all packets */
1027 #define TCP_CONG_NEEDS_ECN 0x2
1028 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN)
1029
1030 union tcp_cc_info;
1031
1032 struct ack_sample {
1033 u32 pkts_acked;
1034 s32 rtt_us;
1035 u32 in_flight;
1036 };
1037
1038 /* A rate sample measures the number of (original/retransmitted) data
1039 * packets delivered "delivered" over an interval of time "interval_us".
1040 * The tcp_rate.c code fills in the rate sample, and congestion
1041 * control modules that define a cong_control function to run at the end
1042 * of ACK processing can optionally chose to consult this sample when
1043 * setting cwnd and pacing rate.
1044 * A sample is invalid if "delivered" or "interval_us" is negative.
1045 */
1046 struct rate_sample {
1047 u64 prior_mstamp; /* starting timestamp for interval */
1048 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */
1049 s32 delivered; /* number of packets delivered over interval */
1050 long interval_us; /* time for tp->delivered to incr "delivered" */
1051 u32 snd_interval_us; /* snd interval for delivered packets */
1052 u32 rcv_interval_us; /* rcv interval for delivered packets */
1053 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */
1054 int losses; /* number of packets marked lost upon ACK */
1055 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */
1056 u32 prior_in_flight; /* in flight before this ACK */
1057 u32 last_end_seq; /* end_seq of most recently ACKed packet */
1058 bool is_app_limited; /* is sample from packet with bubble in pipe? */
1059 bool is_retrans; /* is sample from retransmission? */
1060 bool is_ack_delayed; /* is this (likely) a delayed ACK? */
1061 };
1062
1063 struct tcp_congestion_ops {
1064 struct list_head list;
1065 u32 key;
1066 u32 flags;
1067
1068 /* initialize private data (optional) */
1069 void (*init)(struct sock *sk);
1070 /* cleanup private data (optional) */
1071 void (*release)(struct sock *sk);
1072
1073 /* return slow start threshold (required) */
1074 u32 (*ssthresh)(struct sock *sk);
1075 /* do new cwnd calculation (required) */
1076 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked);
1077 /* call before changing ca_state (optional) */
1078 void (*set_state)(struct sock *sk, u8 new_state);
1079 /* call when cwnd event occurs (optional) */
1080 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
1081 /* call when ack arrives (optional) */
1082 void (*in_ack_event)(struct sock *sk, u32 flags);
1083 /* new value of cwnd after loss (required) */
1084 u32 (*undo_cwnd)(struct sock *sk);
1085 /* hook for packet ack accounting (optional) */
1086 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample);
1087 /* override sysctl_tcp_min_tso_segs */
1088 u32 (*min_tso_segs)(struct sock *sk);
1089 /* returns the multiplier used in tcp_sndbuf_expand (optional) */
1090 u32 (*sndbuf_expand)(struct sock *sk);
1091 /* call when packets are delivered to update cwnd and pacing rate,
1092 * after all the ca_state processing. (optional)
1093 */
1094 void (*cong_control)(struct sock *sk, const struct rate_sample *rs);
1095 /* get info for inet_diag (optional) */
1096 size_t (*get_info)(struct sock *sk, u32 ext, int *attr,
1097 union tcp_cc_info *info);
1098
1099 char name[TCP_CA_NAME_MAX];
1100 struct module *owner;
1101 };
1102
1103 int tcp_register_congestion_control(struct tcp_congestion_ops *type);
1104 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
1105
1106 void tcp_assign_congestion_control(struct sock *sk);
1107 void tcp_init_congestion_control(struct sock *sk);
1108 void tcp_cleanup_congestion_control(struct sock *sk);
1109 int tcp_set_default_congestion_control(struct net *net, const char *name);
1110 void tcp_get_default_congestion_control(struct net *net, char *name);
1111 void tcp_get_available_congestion_control(char *buf, size_t len);
1112 void tcp_get_allowed_congestion_control(char *buf, size_t len);
1113 int tcp_set_allowed_congestion_control(char *allowed);
1114 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
1115 bool cap_net_admin);
1116 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
1117 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
1118
1119 u32 tcp_reno_ssthresh(struct sock *sk);
1120 u32 tcp_reno_undo_cwnd(struct sock *sk);
1121 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked);
1122 extern struct tcp_congestion_ops tcp_reno;
1123
1124 struct tcp_congestion_ops *tcp_ca_find(const char *name);
1125 struct tcp_congestion_ops *tcp_ca_find_key(u32 key);
1126 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca);
1127 #ifdef CONFIG_INET
1128 char *tcp_ca_get_name_by_key(u32 key, char *buffer);
1129 #else
tcp_ca_get_name_by_key(u32 key, char *buffer)1130 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer)
1131 {
1132 return NULL;
1133 }
1134 #endif
1135
tcp_ca_needs_ecn(const struct sock *sk)1136 static inline bool tcp_ca_needs_ecn(const struct sock *sk)
1137 {
1138 const struct inet_connection_sock *icsk = inet_csk(sk);
1139
1140 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN;
1141 }
1142
tcp_set_ca_state(struct sock *sk, const u8 ca_state)1143 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
1144 {
1145 struct inet_connection_sock *icsk = inet_csk(sk);
1146
1147 if (icsk->icsk_ca_ops->set_state)
1148 icsk->icsk_ca_ops->set_state(sk, ca_state);
1149 icsk->icsk_ca_state = ca_state;
1150 }
1151
tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)1152 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
1153 {
1154 const struct inet_connection_sock *icsk = inet_csk(sk);
1155
1156 if (icsk->icsk_ca_ops->cwnd_event)
1157 icsk->icsk_ca_ops->cwnd_event(sk, event);
1158 }
1159
1160 /* From tcp_rate.c */
1161 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
1162 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
1163 struct rate_sample *rs);
1164 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
1165 bool is_sack_reneg, struct rate_sample *rs);
1166 void tcp_rate_check_app_limited(struct sock *sk);
1167
tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2)1168 static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2)
1169 {
1170 return t1 > t2 || (t1 == t2 && after(seq1, seq2));
1171 }
1172
1173 /* These functions determine how the current flow behaves in respect of SACK
1174 * handling. SACK is negotiated with the peer, and therefore it can vary
1175 * between different flows.
1176 *
1177 * tcp_is_sack - SACK enabled
1178 * tcp_is_reno - No SACK
1179 */
tcp_is_sack(const struct tcp_sock *tp)1180 static inline int tcp_is_sack(const struct tcp_sock *tp)
1181 {
1182 return likely(tp->rx_opt.sack_ok);
1183 }
1184
tcp_is_reno(const struct tcp_sock *tp)1185 static inline bool tcp_is_reno(const struct tcp_sock *tp)
1186 {
1187 return !tcp_is_sack(tp);
1188 }
1189
tcp_left_out(const struct tcp_sock *tp)1190 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
1191 {
1192 return tp->sacked_out + tp->lost_out;
1193 }
1194
1195 /* This determines how many packets are "in the network" to the best
1196 * of our knowledge. In many cases it is conservative, but where
1197 * detailed information is available from the receiver (via SACK
1198 * blocks etc.) we can make more aggressive calculations.
1199 *
1200 * Use this for decisions involving congestion control, use just
1201 * tp->packets_out to determine if the send queue is empty or not.
1202 *
1203 * Read this equation as:
1204 *
1205 * "Packets sent once on transmission queue" MINUS
1206 * "Packets left network, but not honestly ACKed yet" PLUS
1207 * "Packets fast retransmitted"
1208 */
tcp_packets_in_flight(const struct tcp_sock *tp)1209 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
1210 {
1211 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
1212 }
1213
1214 #define TCP_INFINITE_SSTHRESH 0x7fffffff
1215
tcp_in_slow_start(const struct tcp_sock *tp)1216 static inline bool tcp_in_slow_start(const struct tcp_sock *tp)
1217 {
1218 return tp->snd_cwnd < tp->snd_ssthresh;
1219 }
1220
tcp_in_initial_slowstart(const struct tcp_sock *tp)1221 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
1222 {
1223 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
1224 }
1225
tcp_in_cwnd_reduction(const struct sock *sk)1226 static inline bool tcp_in_cwnd_reduction(const struct sock *sk)
1227 {
1228 return (TCPF_CA_CWR | TCPF_CA_Recovery) &
1229 (1 << inet_csk(sk)->icsk_ca_state);
1230 }
1231
1232 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
1233 * The exception is cwnd reduction phase, when cwnd is decreasing towards
1234 * ssthresh.
1235 */
tcp_current_ssthresh(const struct sock *sk)1236 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
1237 {
1238 const struct tcp_sock *tp = tcp_sk(sk);
1239
1240 if (tcp_in_cwnd_reduction(sk))
1241 return tp->snd_ssthresh;
1242 else
1243 return max(tp->snd_ssthresh,
1244 ((tp->snd_cwnd >> 1) +
1245 (tp->snd_cwnd >> 2)));
1246 }
1247
1248 /* Use define here intentionally to get WARN_ON location shown at the caller */
1249 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
1250
1251 void tcp_enter_cwr(struct sock *sk);
1252 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst);
1253
1254 /* The maximum number of MSS of available cwnd for which TSO defers
1255 * sending if not using sysctl_tcp_tso_win_divisor.
1256 */
tcp_max_tso_deferred_mss(const struct tcp_sock *tp)1257 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp)
1258 {
1259 return 3;
1260 }
1261
1262 /* Returns end sequence number of the receiver's advertised window */
tcp_wnd_end(const struct tcp_sock *tp)1263 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
1264 {
1265 return tp->snd_una + tp->snd_wnd;
1266 }
1267
1268 /* We follow the spirit of RFC2861 to validate cwnd but implement a more
1269 * flexible approach. The RFC suggests cwnd should not be raised unless
1270 * it was fully used previously. And that's exactly what we do in
1271 * congestion avoidance mode. But in slow start we allow cwnd to grow
1272 * as long as the application has used half the cwnd.
1273 * Example :
1274 * cwnd is 10 (IW10), but application sends 9 frames.
1275 * We allow cwnd to reach 18 when all frames are ACKed.
1276 * This check is safe because it's as aggressive as slow start which already
1277 * risks 100% overshoot. The advantage is that we discourage application to
1278 * either send more filler packets or data to artificially blow up the cwnd
1279 * usage, and allow application-limited process to probe bw more aggressively.
1280 */
tcp_is_cwnd_limited(const struct sock *sk)1281 static inline bool tcp_is_cwnd_limited(const struct sock *sk)
1282 {
1283 const struct tcp_sock *tp = tcp_sk(sk);
1284
1285 if (tp->is_cwnd_limited)
1286 return true;
1287
1288 /* If in slow start, ensure cwnd grows to twice what was ACKed. */
1289 if (tcp_in_slow_start(tp))
1290 return tp->snd_cwnd < 2 * tp->max_packets_out;
1291
1292 return false;
1293 }
1294
1295 /* BBR congestion control needs pacing.
1296 * Same remark for SO_MAX_PACING_RATE.
1297 * sch_fq packet scheduler is efficiently handling pacing,
1298 * but is not always installed/used.
1299 * Return true if TCP stack should pace packets itself.
1300 */
tcp_needs_internal_pacing(const struct sock *sk)1301 static inline bool tcp_needs_internal_pacing(const struct sock *sk)
1302 {
1303 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED;
1304 }
1305
1306 /* Estimates in how many jiffies next packet for this flow can be sent.
1307 * Scheduling a retransmit timer too early would be silly.
1308 */
tcp_pacing_delay(const struct sock *sk)1309 static inline unsigned long tcp_pacing_delay(const struct sock *sk)
1310 {
1311 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache;
1312
1313 return delay > 0 ? nsecs_to_jiffies(delay) : 0;
1314 }
1315
tcp_reset_xmit_timer(struct sock *sk, const int what, unsigned long when, const unsigned long max_when)1316 static inline void tcp_reset_xmit_timer(struct sock *sk,
1317 const int what,
1318 unsigned long when,
1319 const unsigned long max_when)
1320 {
1321 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk),
1322 max_when);
1323 }
1324
1325 /* Something is really bad, we could not queue an additional packet,
1326 * because qdisc is full or receiver sent a 0 window, or we are paced.
1327 * We do not want to add fuel to the fire, or abort too early,
1328 * so make sure the timer we arm now is at least 200ms in the future,
1329 * regardless of current icsk_rto value (as it could be ~2ms)
1330 */
tcp_probe0_base(const struct sock *sk)1331 static inline unsigned long tcp_probe0_base(const struct sock *sk)
1332 {
1333 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN);
1334 }
1335
1336 /* Variant of inet_csk_rto_backoff() used for zero window probes */
tcp_probe0_when(const struct sock *sk, unsigned long max_when)1337 static inline unsigned long tcp_probe0_when(const struct sock *sk,
1338 unsigned long max_when)
1339 {
1340 u64 when = (u64)tcp_probe0_base(sk) << inet_csk(sk)->icsk_backoff;
1341
1342 return (unsigned long)min_t(u64, when, max_when);
1343 }
1344
tcp_check_probe_timer(struct sock *sk)1345 static inline void tcp_check_probe_timer(struct sock *sk)
1346 {
1347 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending)
1348 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
1349 tcp_probe0_base(sk), TCP_RTO_MAX);
1350 }
1351
tcp_init_wl(struct tcp_sock *tp, u32 seq)1352 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
1353 {
1354 tp->snd_wl1 = seq;
1355 }
1356
tcp_update_wl(struct tcp_sock *tp, u32 seq)1357 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
1358 {
1359 tp->snd_wl1 = seq;
1360 }
1361
1362 /*
1363 * Calculate(/check) TCP checksum
1364 */
tcp_v4_check(int len, __be32 saddr, __be32 daddr, __wsum base)1365 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
1366 __be32 daddr, __wsum base)
1367 {
1368 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base);
1369 }
1370
tcp_checksum_complete(struct sk_buff *skb)1371 static inline bool tcp_checksum_complete(struct sk_buff *skb)
1372 {
1373 return !skb_csum_unnecessary(skb) &&
1374 __skb_checksum_complete(skb);
1375 }
1376
1377 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb);
1378 int tcp_filter(struct sock *sk, struct sk_buff *skb);
1379 void tcp_set_state(struct sock *sk, int state);
1380 void tcp_done(struct sock *sk);
1381 int tcp_abort(struct sock *sk, int err);
1382
tcp_sack_reset(struct tcp_options_received *rx_opt)1383 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
1384 {
1385 rx_opt->dsack = 0;
1386 rx_opt->num_sacks = 0;
1387 }
1388
1389 void tcp_cwnd_restart(struct sock *sk, s32 delta);
1390
tcp_slow_start_after_idle_check(struct sock *sk)1391 static inline void tcp_slow_start_after_idle_check(struct sock *sk)
1392 {
1393 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
1394 struct tcp_sock *tp = tcp_sk(sk);
1395 s32 delta;
1396
1397 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) ||
1398 tp->packets_out || ca_ops->cong_control)
1399 return;
1400 delta = tcp_jiffies32 - tp->lsndtime;
1401 if (delta > inet_csk(sk)->icsk_rto)
1402 tcp_cwnd_restart(sk, delta);
1403 }
1404
1405 /* Determine a window scaling and initial window to offer. */
1406 void tcp_select_initial_window(const struct sock *sk, int __space,
1407 __u32 mss, __u32 *rcv_wnd,
1408 __u32 *window_clamp, int wscale_ok,
1409 __u8 *rcv_wscale, __u32 init_rcv_wnd);
1410
tcp_win_from_space(const struct sock *sk, int space)1411 static inline int tcp_win_from_space(const struct sock *sk, int space)
1412 {
1413 int tcp_adv_win_scale = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale);
1414
1415 return tcp_adv_win_scale <= 0 ?
1416 (space>>(-tcp_adv_win_scale)) :
1417 space - (space>>tcp_adv_win_scale);
1418 }
1419
1420 /* Note: caller must be prepared to deal with negative returns */
tcp_space(const struct sock *sk)1421 static inline int tcp_space(const struct sock *sk)
1422 {
1423 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) -
1424 READ_ONCE(sk->sk_backlog.len) -
1425 atomic_read(&sk->sk_rmem_alloc));
1426 }
1427
tcp_full_space(const struct sock *sk)1428 static inline int tcp_full_space(const struct sock *sk)
1429 {
1430 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf));
1431 }
1432
1433 void tcp_cleanup_rbuf(struct sock *sk, int copied);
1434
1435 /* We provision sk_rcvbuf around 200% of sk_rcvlowat.
1436 * If 87.5 % (7/8) of the space has been consumed, we want to override
1437 * SO_RCVLOWAT constraint, since we are receiving skbs with too small
1438 * len/truesize ratio.
1439 */
tcp_rmem_pressure(const struct sock *sk)1440 static inline bool tcp_rmem_pressure(const struct sock *sk)
1441 {
1442 int rcvbuf, threshold;
1443
1444 if (tcp_under_memory_pressure(sk))
1445 return true;
1446
1447 rcvbuf = READ_ONCE(sk->sk_rcvbuf);
1448 threshold = rcvbuf - (rcvbuf >> 3);
1449
1450 return atomic_read(&sk->sk_rmem_alloc) > threshold;
1451 }
1452
1453 extern void tcp_openreq_init_rwin(struct request_sock *req,
1454 const struct sock *sk_listener,
1455 const struct dst_entry *dst);
1456
1457 void tcp_enter_memory_pressure(struct sock *sk);
1458 void tcp_leave_memory_pressure(struct sock *sk);
1459
keepalive_intvl_when(const struct tcp_sock *tp)1460 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1461 {
1462 struct net *net = sock_net((struct sock *)tp);
1463 int val;
1464
1465 /* Paired with WRITE_ONCE() in tcp_sock_set_keepintvl()
1466 * and do_tcp_setsockopt().
1467 */
1468 val = READ_ONCE(tp->keepalive_intvl);
1469
1470 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl);
1471 }
1472
keepalive_time_when(const struct tcp_sock *tp)1473 static inline int keepalive_time_when(const struct tcp_sock *tp)
1474 {
1475 struct net *net = sock_net((struct sock *)tp);
1476 int val;
1477
1478 /* Paired with WRITE_ONCE() in tcp_sock_set_keepidle_locked() */
1479 val = READ_ONCE(tp->keepalive_time);
1480
1481 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time);
1482 }
1483
keepalive_probes(const struct tcp_sock *tp)1484 static inline int keepalive_probes(const struct tcp_sock *tp)
1485 {
1486 struct net *net = sock_net((struct sock *)tp);
1487 int val;
1488
1489 /* Paired with WRITE_ONCE() in tcp_sock_set_keepcnt()
1490 * and do_tcp_setsockopt().
1491 */
1492 val = READ_ONCE(tp->keepalive_probes);
1493
1494 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes);
1495 }
1496
keepalive_time_elapsed(const struct tcp_sock *tp)1497 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
1498 {
1499 const struct inet_connection_sock *icsk = &tp->inet_conn;
1500
1501 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime,
1502 tcp_jiffies32 - tp->rcv_tstamp);
1503 }
1504
tcp_fin_time(const struct sock *sk)1505 static inline int tcp_fin_time(const struct sock *sk)
1506 {
1507 int fin_timeout = tcp_sk(sk)->linger2 ? :
1508 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout);
1509 const int rto = inet_csk(sk)->icsk_rto;
1510
1511 if (fin_timeout < (rto << 2) - (rto >> 1))
1512 fin_timeout = (rto << 2) - (rto >> 1);
1513
1514 return fin_timeout;
1515 }
1516
tcp_paws_check(const struct tcp_options_received *rx_opt, int paws_win)1517 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt,
1518 int paws_win)
1519 {
1520 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1521 return true;
1522 if (unlikely(!time_before32(ktime_get_seconds(),
1523 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)))
1524 return true;
1525 /*
1526 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0,
1527 * then following tcp messages have valid values. Ignore 0 value,
1528 * or else 'negative' tsval might forbid us to accept their packets.
1529 */
1530 if (!rx_opt->ts_recent)
1531 return true;
1532 return false;
1533 }
1534
tcp_paws_reject(const struct tcp_options_received *rx_opt, int rst)1535 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt,
1536 int rst)
1537 {
1538 if (tcp_paws_check(rx_opt, 0))
1539 return false;
1540
1541 /* RST segments are not recommended to carry timestamp,
1542 and, if they do, it is recommended to ignore PAWS because
1543 "their cleanup function should take precedence over timestamps."
1544 Certainly, it is mistake. It is necessary to understand the reasons
1545 of this constraint to relax it: if peer reboots, clock may go
1546 out-of-sync and half-open connections will not be reset.
1547 Actually, the problem would be not existing if all
1548 the implementations followed draft about maintaining clock
1549 via reboots. Linux-2.2 DOES NOT!
1550
1551 However, we can relax time bounds for RST segments to MSL.
1552 */
1553 if (rst && !time_before32(ktime_get_seconds(),
1554 rx_opt->ts_recent_stamp + TCP_PAWS_MSL))
1555 return false;
1556 return true;
1557 }
1558
1559 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
1560 int mib_idx, u32 *last_oow_ack_time);
1561
tcp_mib_init(struct net *net)1562 static inline void tcp_mib_init(struct net *net)
1563 {
1564 /* See RFC 2012 */
1565 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1);
1566 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1567 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1568 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1);
1569 }
1570
1571 /* from STCP */
tcp_clear_retrans_hints_partial(struct tcp_sock *tp)1572 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1573 {
1574 tp->lost_skb_hint = NULL;
1575 }
1576
tcp_clear_all_retrans_hints(struct tcp_sock *tp)1577 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1578 {
1579 tcp_clear_retrans_hints_partial(tp);
1580 tp->retransmit_skb_hint = NULL;
1581 }
1582
1583 union tcp_md5_addr {
1584 struct in_addr a4;
1585 #if IS_ENABLED(CONFIG_IPV6)
1586 struct in6_addr a6;
1587 #endif
1588 };
1589
1590 /* - key database */
1591 struct tcp_md5sig_key {
1592 struct hlist_node node;
1593 u8 keylen;
1594 u8 family; /* AF_INET or AF_INET6 */
1595 u8 prefixlen;
1596 union tcp_md5_addr addr;
1597 int l3index; /* set if key added with L3 scope */
1598 u8 key[TCP_MD5SIG_MAXKEYLEN];
1599 struct rcu_head rcu;
1600 };
1601
1602 /* - sock block */
1603 struct tcp_md5sig_info {
1604 struct hlist_head head;
1605 struct rcu_head rcu;
1606 };
1607
1608 /* - pseudo header */
1609 struct tcp4_pseudohdr {
1610 __be32 saddr;
1611 __be32 daddr;
1612 __u8 pad;
1613 __u8 protocol;
1614 __be16 len;
1615 };
1616
1617 struct tcp6_pseudohdr {
1618 struct in6_addr saddr;
1619 struct in6_addr daddr;
1620 __be32 len;
1621 __be32 protocol; /* including padding */
1622 };
1623
1624 union tcp_md5sum_block {
1625 struct tcp4_pseudohdr ip4;
1626 #if IS_ENABLED(CONFIG_IPV6)
1627 struct tcp6_pseudohdr ip6;
1628 #endif
1629 };
1630
1631 /* - pool: digest algorithm, hash description and scratch buffer */
1632 struct tcp_md5sig_pool {
1633 struct ahash_request *md5_req;
1634 void *scratch;
1635 };
1636
1637 /* - functions */
1638 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1639 const struct sock *sk, const struct sk_buff *skb);
1640 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1641 int family, u8 prefixlen, int l3index,
1642 const u8 *newkey, u8 newkeylen, gfp_t gfp);
1643 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
1644 int family, u8 prefixlen, int l3index);
1645 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1646 const struct sock *addr_sk);
1647
1648 #ifdef CONFIG_TCP_MD5SIG
1649 #include <linux/jump_label.h>
1650 extern struct static_key_false tcp_md5_needed;
1651 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1652 const union tcp_md5_addr *addr,
1653 int family);
1654 static inline struct tcp_md5sig_key *
tcp_md5_do_lookup(const struct sock *sk, int l3index, const union tcp_md5_addr *addr, int family)1655 tcp_md5_do_lookup(const struct sock *sk, int l3index,
1656 const union tcp_md5_addr *addr, int family)
1657 {
1658 if (!static_branch_unlikely(&tcp_md5_needed))
1659 return NULL;
1660 return __tcp_md5_do_lookup(sk, l3index, addr, family);
1661 }
1662
1663 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key)
1664 #else
1665 static inline struct tcp_md5sig_key *
tcp_md5_do_lookup(const struct sock *sk, int l3index, const union tcp_md5_addr *addr, int family)1666 tcp_md5_do_lookup(const struct sock *sk, int l3index,
1667 const union tcp_md5_addr *addr, int family)
1668 {
1669 return NULL;
1670 }
1671 #define tcp_twsk_md5_key(twsk) NULL
1672 #endif
1673
1674 bool tcp_alloc_md5sig_pool(void);
1675
1676 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void);
tcp_put_md5sig_pool(void)1677 static inline void tcp_put_md5sig_pool(void)
1678 {
1679 local_bh_enable();
1680 }
1681
1682 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *,
1683 unsigned int header_len);
1684 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1685 const struct tcp_md5sig_key *key);
1686
1687 /* From tcp_fastopen.c */
1688 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
1689 struct tcp_fastopen_cookie *cookie);
1690 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
1691 struct tcp_fastopen_cookie *cookie, bool syn_lost,
1692 u16 try_exp);
1693 struct tcp_fastopen_request {
1694 /* Fast Open cookie. Size 0 means a cookie request */
1695 struct tcp_fastopen_cookie cookie;
1696 struct msghdr *data; /* data in MSG_FASTOPEN */
1697 size_t size;
1698 int copied; /* queued in tcp_connect() */
1699 struct ubuf_info *uarg;
1700 };
1701 void tcp_free_fastopen_req(struct tcp_sock *tp);
1702 void tcp_fastopen_destroy_cipher(struct sock *sk);
1703 void tcp_fastopen_ctx_destroy(struct net *net);
1704 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
1705 void *primary_key, void *backup_key);
1706 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk,
1707 u64 *key);
1708 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
1709 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
1710 struct request_sock *req,
1711 struct tcp_fastopen_cookie *foc,
1712 const struct dst_entry *dst);
1713 void tcp_fastopen_init_key_once(struct net *net);
1714 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss,
1715 struct tcp_fastopen_cookie *cookie);
1716 bool tcp_fastopen_defer_connect(struct sock *sk, int *err);
1717 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t)
1718 #define TCP_FASTOPEN_KEY_MAX 2
1719 #define TCP_FASTOPEN_KEY_BUF_LENGTH \
1720 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX)
1721
1722 /* Fastopen key context */
1723 struct tcp_fastopen_context {
1724 siphash_key_t key[TCP_FASTOPEN_KEY_MAX];
1725 int num;
1726 struct rcu_head rcu;
1727 };
1728
1729 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout;
1730 void tcp_fastopen_active_disable(struct sock *sk);
1731 bool tcp_fastopen_active_should_disable(struct sock *sk);
1732 void tcp_fastopen_active_disable_ofo_check(struct sock *sk);
1733 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired);
1734
1735 /* Caller needs to wrap with rcu_read_(un)lock() */
1736 static inline
tcp_fastopen_get_ctx(const struct sock *sk)1737 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk)
1738 {
1739 struct tcp_fastopen_context *ctx;
1740
1741 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx);
1742 if (!ctx)
1743 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx);
1744 return ctx;
1745 }
1746
1747 static inline
tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, const struct tcp_fastopen_cookie *orig)1748 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc,
1749 const struct tcp_fastopen_cookie *orig)
1750 {
1751 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE &&
1752 orig->len == foc->len &&
1753 !memcmp(orig->val, foc->val, foc->len))
1754 return true;
1755 return false;
1756 }
1757
1758 static inline
tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx)1759 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx)
1760 {
1761 return ctx->num;
1762 }
1763
1764 /* Latencies incurred by various limits for a sender. They are
1765 * chronograph-like stats that are mutually exclusive.
1766 */
1767 enum tcp_chrono {
1768 TCP_CHRONO_UNSPEC,
1769 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */
1770 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */
1771 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */
1772 __TCP_CHRONO_MAX,
1773 };
1774
1775 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type);
1776 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type);
1777
1778 /* This helper is needed, because skb->tcp_tsorted_anchor uses
1779 * the same memory storage than skb->destructor/_skb_refdst
1780 */
tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb)1781 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb)
1782 {
1783 skb->destructor = NULL;
1784 skb->_skb_refdst = 0UL;
1785 }
1786
1787 #define tcp_skb_tsorted_save(skb) { \
1788 unsigned long _save = skb->_skb_refdst; \
1789 skb->_skb_refdst = 0UL;
1790
1791 #define tcp_skb_tsorted_restore(skb) \
1792 skb->_skb_refdst = _save; \
1793 }
1794
1795 void tcp_write_queue_purge(struct sock *sk);
1796
tcp_rtx_queue_head(const struct sock *sk)1797 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk)
1798 {
1799 return skb_rb_first(&sk->tcp_rtx_queue);
1800 }
1801
tcp_rtx_queue_tail(const struct sock *sk)1802 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk)
1803 {
1804 return skb_rb_last(&sk->tcp_rtx_queue);
1805 }
1806
tcp_write_queue_head(const struct sock *sk)1807 static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk)
1808 {
1809 return skb_peek(&sk->sk_write_queue);
1810 }
1811
tcp_write_queue_tail(const struct sock *sk)1812 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk)
1813 {
1814 return skb_peek_tail(&sk->sk_write_queue);
1815 }
1816
1817 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1818 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1819
tcp_send_head(const struct sock *sk)1820 static inline struct sk_buff *tcp_send_head(const struct sock *sk)
1821 {
1822 return skb_peek(&sk->sk_write_queue);
1823 }
1824
tcp_skb_is_last(const struct sock *sk, const struct sk_buff *skb)1825 static inline bool tcp_skb_is_last(const struct sock *sk,
1826 const struct sk_buff *skb)
1827 {
1828 return skb_queue_is_last(&sk->sk_write_queue, skb);
1829 }
1830
1831 /**
1832 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue
1833 * @sk: socket
1834 *
1835 * Since the write queue can have a temporary empty skb in it,
1836 * we must not use "return skb_queue_empty(&sk->sk_write_queue)"
1837 */
tcp_write_queue_empty(const struct sock *sk)1838 static inline bool tcp_write_queue_empty(const struct sock *sk)
1839 {
1840 const struct tcp_sock *tp = tcp_sk(sk);
1841
1842 return tp->write_seq == tp->snd_nxt;
1843 }
1844
tcp_rtx_queue_empty(const struct sock *sk)1845 static inline bool tcp_rtx_queue_empty(const struct sock *sk)
1846 {
1847 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue);
1848 }
1849
tcp_rtx_and_write_queues_empty(const struct sock *sk)1850 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk)
1851 {
1852 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk);
1853 }
1854
tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)1855 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1856 {
1857 __skb_queue_tail(&sk->sk_write_queue, skb);
1858
1859 /* Queue it, remembering where we must start sending. */
1860 if (sk->sk_write_queue.next == skb)
1861 tcp_chrono_start(sk, TCP_CHRONO_BUSY);
1862 }
1863
1864 /* Insert new before skb on the write queue of sk. */
tcp_insert_write_queue_before(struct sk_buff *new, struct sk_buff *skb, struct sock *sk)1865 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1866 struct sk_buff *skb,
1867 struct sock *sk)
1868 {
1869 __skb_queue_before(&sk->sk_write_queue, skb, new);
1870 }
1871
tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)1872 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1873 {
1874 tcp_skb_tsorted_anchor_cleanup(skb);
1875 __skb_unlink(skb, &sk->sk_write_queue);
1876 }
1877
1878 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb);
1879
tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk)1880 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk)
1881 {
1882 tcp_skb_tsorted_anchor_cleanup(skb);
1883 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue);
1884 }
1885
tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk)1886 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk)
1887 {
1888 list_del(&skb->tcp_tsorted_anchor);
1889 tcp_rtx_queue_unlink(skb, sk);
1890 sk_wmem_free_skb(sk, skb);
1891 }
1892
tcp_push_pending_frames(struct sock *sk)1893 static inline void tcp_push_pending_frames(struct sock *sk)
1894 {
1895 if (tcp_send_head(sk)) {
1896 struct tcp_sock *tp = tcp_sk(sk);
1897
1898 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
1899 }
1900 }
1901
1902 /* Start sequence of the skb just after the highest skb with SACKed
1903 * bit, valid only if sacked_out > 0 or when the caller has ensured
1904 * validity by itself.
1905 */
tcp_highest_sack_seq(struct tcp_sock *tp)1906 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1907 {
1908 if (!tp->sacked_out)
1909 return tp->snd_una;
1910
1911 if (tp->highest_sack == NULL)
1912 return tp->snd_nxt;
1913
1914 return TCP_SKB_CB(tp->highest_sack)->seq;
1915 }
1916
tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)1917 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1918 {
1919 tcp_sk(sk)->highest_sack = skb_rb_next(skb);
1920 }
1921
tcp_highest_sack(struct sock *sk)1922 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1923 {
1924 return tcp_sk(sk)->highest_sack;
1925 }
1926
tcp_highest_sack_reset(struct sock *sk)1927 static inline void tcp_highest_sack_reset(struct sock *sk)
1928 {
1929 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk);
1930 }
1931
1932 /* Called when old skb is about to be deleted and replaced by new skb */
tcp_highest_sack_replace(struct sock *sk, struct sk_buff *old, struct sk_buff *new)1933 static inline void tcp_highest_sack_replace(struct sock *sk,
1934 struct sk_buff *old,
1935 struct sk_buff *new)
1936 {
1937 if (old == tcp_highest_sack(sk))
1938 tcp_sk(sk)->highest_sack = new;
1939 }
1940
1941 /* This helper checks if socket has IP_TRANSPARENT set */
inet_sk_transparent(const struct sock *sk)1942 static inline bool inet_sk_transparent(const struct sock *sk)
1943 {
1944 switch (sk->sk_state) {
1945 case TCP_TIME_WAIT:
1946 return inet_twsk(sk)->tw_transparent;
1947 case TCP_NEW_SYN_RECV:
1948 return inet_rsk(inet_reqsk(sk))->no_srccheck;
1949 }
1950 return inet_sk(sk)->transparent;
1951 }
1952
1953 /* Determines whether this is a thin stream (which may suffer from
1954 * increased latency). Used to trigger latency-reducing mechanisms.
1955 */
tcp_stream_is_thin(struct tcp_sock *tp)1956 static inline bool tcp_stream_is_thin(struct tcp_sock *tp)
1957 {
1958 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp);
1959 }
1960
1961 /* /proc */
1962 enum tcp_seq_states {
1963 TCP_SEQ_STATE_LISTENING,
1964 TCP_SEQ_STATE_ESTABLISHED,
1965 };
1966
1967 void *tcp_seq_start(struct seq_file *seq, loff_t *pos);
1968 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
1969 void tcp_seq_stop(struct seq_file *seq, void *v);
1970
1971 struct tcp_seq_afinfo {
1972 sa_family_t family;
1973 };
1974
1975 struct tcp_iter_state {
1976 struct seq_net_private p;
1977 enum tcp_seq_states state;
1978 struct sock *syn_wait_sk;
1979 struct tcp_seq_afinfo *bpf_seq_afinfo;
1980 int bucket, offset, sbucket, num;
1981 loff_t last_pos;
1982 };
1983
1984 extern struct request_sock_ops tcp_request_sock_ops;
1985 extern struct request_sock_ops tcp6_request_sock_ops;
1986
1987 void tcp_v4_destroy_sock(struct sock *sk);
1988
1989 struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
1990 netdev_features_t features);
1991 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb);
1992 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff));
1993 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb));
1994 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff));
1995 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb));
1996 int tcp_gro_complete(struct sk_buff *skb);
1997
1998 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
1999
tcp_notsent_lowat(const struct tcp_sock *tp)2000 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
2001 {
2002 struct net *net = sock_net((struct sock *)tp);
2003 u32 val;
2004
2005 val = READ_ONCE(tp->notsent_lowat);
2006
2007 return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
2008 }
2009
2010 /* @wake is one when sk_stream_write_space() calls us.
2011 * This sends EPOLLOUT only if notsent_bytes is half the limit.
2012 * This mimics the strategy used in sock_def_write_space().
2013 */
tcp_stream_memory_free(const struct sock *sk, int wake)2014 static inline bool tcp_stream_memory_free(const struct sock *sk, int wake)
2015 {
2016 const struct tcp_sock *tp = tcp_sk(sk);
2017 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
2018 READ_ONCE(tp->snd_nxt);
2019
2020 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
2021 }
2022
2023 #ifdef CONFIG_PROC_FS
2024 int tcp4_proc_init(void);
2025 void tcp4_proc_exit(void);
2026 #endif
2027
2028 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req);
2029 int tcp_conn_request(struct request_sock_ops *rsk_ops,
2030 const struct tcp_request_sock_ops *af_ops,
2031 struct sock *sk, struct sk_buff *skb);
2032
2033 /* TCP af-specific functions */
2034 struct tcp_sock_af_ops {
2035 #ifdef CONFIG_TCP_MD5SIG
2036 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk,
2037 const struct sock *addr_sk);
2038 int (*calc_md5_hash)(char *location,
2039 const struct tcp_md5sig_key *md5,
2040 const struct sock *sk,
2041 const struct sk_buff *skb);
2042 int (*md5_parse)(struct sock *sk,
2043 int optname,
2044 sockptr_t optval,
2045 int optlen);
2046 #endif
2047 };
2048
2049 struct tcp_request_sock_ops {
2050 u16 mss_clamp;
2051 #ifdef CONFIG_TCP_MD5SIG
2052 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk,
2053 const struct sock *addr_sk);
2054 int (*calc_md5_hash) (char *location,
2055 const struct tcp_md5sig_key *md5,
2056 const struct sock *sk,
2057 const struct sk_buff *skb);
2058 #endif
2059 void (*init_req)(struct request_sock *req,
2060 const struct sock *sk_listener,
2061 struct sk_buff *skb);
2062 #ifdef CONFIG_SYN_COOKIES
2063 __u32 (*cookie_init_seq)(const struct sk_buff *skb,
2064 __u16 *mss);
2065 #endif
2066 struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl,
2067 const struct request_sock *req);
2068 u32 (*init_seq)(const struct sk_buff *skb);
2069 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb);
2070 int (*send_synack)(const struct sock *sk, struct dst_entry *dst,
2071 struct flowi *fl, struct request_sock *req,
2072 struct tcp_fastopen_cookie *foc,
2073 enum tcp_synack_type synack_type,
2074 struct sk_buff *syn_skb);
2075 };
2076
2077 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops;
2078 #if IS_ENABLED(CONFIG_IPV6)
2079 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops;
2080 #endif
2081
2082 #ifdef CONFIG_SYN_COOKIES
cookie_init_sequence(const struct tcp_request_sock_ops *ops, const struct sock *sk, struct sk_buff *skb, __u16 *mss)2083 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
2084 const struct sock *sk, struct sk_buff *skb,
2085 __u16 *mss)
2086 {
2087 tcp_synq_overflow(sk);
2088 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);
2089 return ops->cookie_init_seq(skb, mss);
2090 }
2091 #else
cookie_init_sequence(const struct tcp_request_sock_ops *ops, const struct sock *sk, struct sk_buff *skb, __u16 *mss)2092 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
2093 const struct sock *sk, struct sk_buff *skb,
2094 __u16 *mss)
2095 {
2096 return 0;
2097 }
2098 #endif
2099
2100 int tcpv4_offload_init(void);
2101
2102 void tcp_v4_init(void);
2103 void tcp_init(void);
2104
2105 /* tcp_recovery.c */
2106 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb);
2107 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced);
2108 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb,
2109 u32 reo_wnd);
2110 extern bool tcp_rack_mark_lost(struct sock *sk);
2111 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
2112 u64 xmit_time);
2113 extern void tcp_rack_reo_timeout(struct sock *sk);
2114 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs);
2115
2116 /* At how many usecs into the future should the RTO fire? */
tcp_rto_delta_us(const struct sock *sk)2117 static inline s64 tcp_rto_delta_us(const struct sock *sk)
2118 {
2119 const struct sk_buff *skb = tcp_rtx_queue_head(sk);
2120 u32 rto = inet_csk(sk)->icsk_rto;
2121 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto);
2122
2123 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp;
2124 }
2125
2126 /*
2127 * Save and compile IPv4 options, return a pointer to it
2128 */
tcp_v4_save_options(struct net *net, struct sk_buff *skb)2129 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net,
2130 struct sk_buff *skb)
2131 {
2132 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt;
2133 struct ip_options_rcu *dopt = NULL;
2134
2135 if (opt->optlen) {
2136 int opt_size = sizeof(*dopt) + opt->optlen;
2137
2138 dopt = kmalloc(opt_size, GFP_ATOMIC);
2139 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) {
2140 kfree(dopt);
2141 dopt = NULL;
2142 }
2143 }
2144 return dopt;
2145 }
2146
2147 /* locally generated TCP pure ACKs have skb->truesize == 2
2148 * (check tcp_send_ack() in net/ipv4/tcp_output.c )
2149 * This is much faster than dissecting the packet to find out.
2150 * (Think of GRE encapsulations, IPv4, IPv6, ...)
2151 */
skb_is_tcp_pure_ack(const struct sk_buff *skb)2152 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb)
2153 {
2154 return skb->truesize == 2;
2155 }
2156
skb_set_tcp_pure_ack(struct sk_buff *skb)2157 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb)
2158 {
2159 skb->truesize = 2;
2160 }
2161
tcp_inq(struct sock *sk)2162 static inline int tcp_inq(struct sock *sk)
2163 {
2164 struct tcp_sock *tp = tcp_sk(sk);
2165 int answ;
2166
2167 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
2168 answ = 0;
2169 } else if (sock_flag(sk, SOCK_URGINLINE) ||
2170 !tp->urg_data ||
2171 before(tp->urg_seq, tp->copied_seq) ||
2172 !before(tp->urg_seq, tp->rcv_nxt)) {
2173
2174 answ = tp->rcv_nxt - tp->copied_seq;
2175
2176 /* Subtract 1, if FIN was received */
2177 if (answ && sock_flag(sk, SOCK_DONE))
2178 answ--;
2179 } else {
2180 answ = tp->urg_seq - tp->copied_seq;
2181 }
2182
2183 return answ;
2184 }
2185
2186 int tcp_peek_len(struct socket *sock);
2187
tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)2188 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)
2189 {
2190 u16 segs_in;
2191
2192 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2193 tp->segs_in += segs_in;
2194 if (skb->len > tcp_hdrlen(skb))
2195 tp->data_segs_in += segs_in;
2196 }
2197
2198 /*
2199 * TCP listen path runs lockless.
2200 * We forced "struct sock" to be const qualified to make sure
2201 * we don't modify one of its field by mistake.
2202 * Here, we increment sk_drops which is an atomic_t, so we can safely
2203 * make sock writable again.
2204 */
tcp_listendrop(const struct sock *sk)2205 static inline void tcp_listendrop(const struct sock *sk)
2206 {
2207 atomic_inc(&((struct sock *)sk)->sk_drops);
2208 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
2209 }
2210
2211 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer);
2212
2213 /*
2214 * Interface for adding Upper Level Protocols over TCP
2215 */
2216
2217 #define TCP_ULP_NAME_MAX 16
2218 #define TCP_ULP_MAX 128
2219 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX)
2220
2221 struct tcp_ulp_ops {
2222 struct list_head list;
2223
2224 /* initialize ulp */
2225 int (*init)(struct sock *sk);
2226 /* update ulp */
2227 void (*update)(struct sock *sk, struct proto *p,
2228 void (*write_space)(struct sock *sk));
2229 /* cleanup ulp */
2230 void (*release)(struct sock *sk);
2231 /* diagnostic */
2232 int (*get_info)(const struct sock *sk, struct sk_buff *skb);
2233 size_t (*get_info_size)(const struct sock *sk);
2234 /* clone ulp */
2235 void (*clone)(const struct request_sock *req, struct sock *newsk,
2236 const gfp_t priority);
2237
2238 char name[TCP_ULP_NAME_MAX];
2239 struct module *owner;
2240 };
2241 int tcp_register_ulp(struct tcp_ulp_ops *type);
2242 void tcp_unregister_ulp(struct tcp_ulp_ops *type);
2243 int tcp_set_ulp(struct sock *sk, const char *name);
2244 void tcp_get_available_ulp(char *buf, size_t len);
2245 void tcp_cleanup_ulp(struct sock *sk);
2246 void tcp_update_ulp(struct sock *sk, struct proto *p,
2247 void (*write_space)(struct sock *sk));
2248
2249 #define MODULE_ALIAS_TCP_ULP(name) \
2250 __MODULE_INFO(alias, alias_userspace, name); \
2251 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name)
2252
2253 struct sk_msg;
2254 struct sk_psock;
2255
2256 #ifdef CONFIG_BPF_STREAM_PARSER
2257 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
2258 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk);
2259 #else
tcp_bpf_clone(const struct sock *sk, struct sock *newsk)2260 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
2261 {
2262 }
2263 #endif /* CONFIG_BPF_STREAM_PARSER */
2264
2265 #ifdef CONFIG_NET_SOCK_MSG
2266 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes,
2267 int flags);
2268 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
2269 struct msghdr *msg, int len, int flags);
2270 #endif /* CONFIG_NET_SOCK_MSG */
2271
2272 #ifdef CONFIG_CGROUP_BPF
bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, struct sk_buff *skb, unsigned int end_offset)2273 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
2274 struct sk_buff *skb,
2275 unsigned int end_offset)
2276 {
2277 skops->skb = skb;
2278 skops->skb_data_end = skb->data + end_offset;
2279 }
2280 #else
bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, struct sk_buff *skb, unsigned int end_offset)2281 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
2282 struct sk_buff *skb,
2283 unsigned int end_offset)
2284 {
2285 }
2286 #endif
2287
2288 /* Call BPF_SOCK_OPS program that returns an int. If the return value
2289 * is < 0, then the BPF op failed (for example if the loaded BPF
2290 * program does not support the chosen operation or there is no BPF
2291 * program loaded).
2292 */
2293 #ifdef CONFIG_BPF
tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)2294 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
2295 {
2296 struct bpf_sock_ops_kern sock_ops;
2297 int ret;
2298
2299 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
2300 if (sk_fullsock(sk)) {
2301 sock_ops.is_fullsock = 1;
2302 sock_owned_by_me(sk);
2303 }
2304
2305 sock_ops.sk = sk;
2306 sock_ops.op = op;
2307 if (nargs > 0)
2308 memcpy(sock_ops.args, args, nargs * sizeof(*args));
2309
2310 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops);
2311 if (ret == 0)
2312 ret = sock_ops.reply;
2313 else
2314 ret = -1;
2315 return ret;
2316 }
2317
tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)2318 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)
2319 {
2320 u32 args[2] = {arg1, arg2};
2321
2322 return tcp_call_bpf(sk, op, 2, args);
2323 }
2324
tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, u32 arg3)2325 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
2326 u32 arg3)
2327 {
2328 u32 args[3] = {arg1, arg2, arg3};
2329
2330 return tcp_call_bpf(sk, op, 3, args);
2331 }
2332
2333 #else
tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)2334 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
2335 {
2336 return -EPERM;
2337 }
2338
tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)2339 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)
2340 {
2341 return -EPERM;
2342 }
2343
tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, u32 arg3)2344 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
2345 u32 arg3)
2346 {
2347 return -EPERM;
2348 }
2349
2350 #endif
2351
tcp_timeout_init(struct sock *sk)2352 static inline u32 tcp_timeout_init(struct sock *sk)
2353 {
2354 int timeout;
2355
2356 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL);
2357
2358 if (timeout <= 0)
2359 timeout = TCP_TIMEOUT_INIT;
2360 return timeout;
2361 }
2362
tcp_rwnd_init_bpf(struct sock *sk)2363 static inline u32 tcp_rwnd_init_bpf(struct sock *sk)
2364 {
2365 int rwnd;
2366
2367 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL);
2368
2369 if (rwnd < 0)
2370 rwnd = 0;
2371 return rwnd;
2372 }
2373
tcp_bpf_ca_needs_ecn(struct sock *sk)2374 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk)
2375 {
2376 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1);
2377 }
2378
tcp_bpf_rtt(struct sock *sk)2379 static inline void tcp_bpf_rtt(struct sock *sk)
2380 {
2381 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG))
2382 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL);
2383 }
2384
2385 #if IS_ENABLED(CONFIG_SMC)
2386 extern struct static_key_false tcp_have_smc;
2387 #endif
2388
2389 #if IS_ENABLED(CONFIG_TLS_DEVICE)
2390 void clean_acked_data_enable(struct inet_connection_sock *icsk,
2391 void (*cad)(struct sock *sk, u32 ack_seq));
2392 void clean_acked_data_disable(struct inet_connection_sock *icsk);
2393 void clean_acked_data_flush(void);
2394 #endif
2395
2396 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled);
tcp_add_tx_delay(struct sk_buff *skb, const struct tcp_sock *tp)2397 static inline void tcp_add_tx_delay(struct sk_buff *skb,
2398 const struct tcp_sock *tp)
2399 {
2400 if (static_branch_unlikely(&tcp_tx_delay_enabled))
2401 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC;
2402 }
2403
2404 /* Compute Earliest Departure Time for some control packets
2405 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets.
2406 */
tcp_transmit_time(const struct sock *sk)2407 static inline u64 tcp_transmit_time(const struct sock *sk)
2408 {
2409 if (static_branch_unlikely(&tcp_tx_delay_enabled)) {
2410 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ?
2411 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay;
2412
2413 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC;
2414 }
2415 return 0;
2416 }
2417
2418 #endif /* _TCP_H */
2419