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