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1 | /* | |
2 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
3 | * operating system. INET is implemented using the BSD Socket | |
4 | * interface as the means of communication with the user level. | |
5 | * | |
6 | * Definitions for the TCP module. | |
7 | * | |
8 | * Version: @(#)tcp.h 1.0.5 05/23/93 | |
9 | * | |
10 | * Authors: Ross Biro | |
11 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or | |
14 | * modify it under the terms of the GNU General Public License | |
15 | * as published by the Free Software Foundation; either version | |
16 | * 2 of the License, or (at your option) any later version. | |
17 | */ | |
18 | #ifndef _TCP_H | |
19 | #define _TCP_H | |
20 | ||
21 | #define FASTRETRANS_DEBUG 1 | |
22 | ||
23 | #include <linux/list.h> | |
24 | #include <linux/tcp.h> | |
25 | #include <linux/bug.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/cache.h> | |
28 | #include <linux/percpu.h> | |
29 | #include <linux/skbuff.h> | |
30 | #include <linux/cryptohash.h> | |
31 | #include <linux/kref.h> | |
32 | #include <linux/ktime.h> | |
33 | ||
34 | #include <net/inet_connection_sock.h> | |
35 | #include <net/inet_timewait_sock.h> | |
36 | #include <net/inet_hashtables.h> | |
37 | #include <net/checksum.h> | |
38 | #include <net/request_sock.h> | |
39 | #include <net/sock_reuseport.h> | |
40 | #include <net/sock.h> | |
41 | #include <net/snmp.h> | |
42 | #include <net/ip.h> | |
43 | #include <net/tcp_states.h> | |
44 | #include <net/inet_ecn.h> | |
45 | #include <net/dst.h> | |
46 | ||
47 | #include <linux/seq_file.h> | |
48 | #include <linux/memcontrol.h> | |
49 | #include <linux/bpf-cgroup.h> | |
50 | ||
51 | extern struct inet_hashinfo tcp_hashinfo; | |
52 | ||
53 | extern struct percpu_counter tcp_orphan_count; | |
54 | void tcp_time_wait(struct sock *sk, int state, int timeo); | |
55 | ||
56 | #define MAX_TCP_HEADER (128 + MAX_HEADER) | |
57 | #define MAX_TCP_OPTION_SPACE 40 | |
58 | ||
59 | /* | |
60 | * Never offer a window over 32767 without using window scaling. Some | |
61 | * poor stacks do signed 16bit maths! | |
62 | */ | |
63 | #define MAX_TCP_WINDOW 32767U | |
64 | ||
65 | /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ | |
66 | #define TCP_MIN_MSS 88U | |
67 | ||
68 | /* The least MTU to use for probing */ | |
69 | #define TCP_BASE_MSS 1024 | |
70 | ||
71 | /* probing interval, default to 10 minutes as per RFC4821 */ | |
72 | #define TCP_PROBE_INTERVAL 600 | |
73 | ||
74 | /* Specify interval when tcp mtu probing will stop */ | |
75 | #define TCP_PROBE_THRESHOLD 8 | |
76 | ||
77 | /* After receiving this amount of duplicate ACKs fast retransmit starts. */ | |
78 | #define TCP_FASTRETRANS_THRESH 3 | |
79 | ||
80 | /* Maximal number of ACKs sent quickly to accelerate slow-start. */ | |
81 | #define TCP_MAX_QUICKACKS 16U | |
82 | ||
83 | /* Maximal number of window scale according to RFC1323 */ | |
84 | #define TCP_MAX_WSCALE 14U | |
85 | ||
86 | /* urg_data states */ | |
87 | #define TCP_URG_VALID 0x0100 | |
88 | #define TCP_URG_NOTYET 0x0200 | |
89 | #define TCP_URG_READ 0x0400 | |
90 | ||
91 | #define TCP_RETR1 3 /* | |
92 | * This is how many retries it does before it | |
93 | * tries to figure out if the gateway is | |
94 | * down. Minimal RFC value is 3; it corresponds | |
95 | * to ~3sec-8min depending on RTO. | |
96 | */ | |
97 | ||
98 | #define TCP_RETR2 15 /* | |
99 | * This should take at least | |
100 | * 90 minutes to time out. | |
101 | * RFC1122 says that the limit is 100 sec. | |
102 | * 15 is ~13-30min depending on RTO. | |
103 | */ | |
104 | ||
105 | #define TCP_SYN_RETRIES 6 /* This is how many retries are done | |
106 | * when active opening a connection. | |
107 | * RFC1122 says the minimum retry MUST | |
108 | * be at least 180secs. Nevertheless | |
109 | * this value is corresponding to | |
110 | * 63secs of retransmission with the | |
111 | * current initial RTO. | |
112 | */ | |
113 | ||
114 | #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done | |
115 | * when passive opening a connection. | |
116 | * This is corresponding to 31secs of | |
117 | * retransmission with the current | |
118 | * initial RTO. | |
119 | */ | |
120 | ||
121 | #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT | |
122 | * state, about 60 seconds */ | |
123 | #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN | |
124 | /* BSD style FIN_WAIT2 deadlock breaker. | |
125 | * It used to be 3min, new value is 60sec, | |
126 | * to combine FIN-WAIT-2 timeout with | |
127 | * TIME-WAIT timer. | |
128 | */ | |
129 | ||
130 | #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ | |
131 | #if HZ >= 100 | |
132 | #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ | |
133 | #define TCP_ATO_MIN ((unsigned)(HZ/25)) | |
134 | #else | |
135 | #define TCP_DELACK_MIN 4U | |
136 | #define TCP_ATO_MIN 4U | |
137 | #endif | |
138 | #define TCP_RTO_MAX ((unsigned)(120*HZ)) | |
139 | #define TCP_RTO_MIN ((unsigned)(HZ/5)) | |
140 | #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ | |
141 | #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ | |
142 | #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now | |
143 | * used as a fallback RTO for the | |
144 | * initial data transmission if no | |
145 | * valid RTT sample has been acquired, | |
146 | * most likely due to retrans in 3WHS. | |
147 | */ | |
148 | ||
149 | #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes | |
150 | * for local resources. | |
151 | */ | |
152 | #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ | |
153 | #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ | |
154 | #define TCP_KEEPALIVE_INTVL (75*HZ) | |
155 | ||
156 | #define MAX_TCP_KEEPIDLE 32767 | |
157 | #define MAX_TCP_KEEPINTVL 32767 | |
158 | #define MAX_TCP_KEEPCNT 127 | |
159 | #define MAX_TCP_SYNCNT 127 | |
160 | ||
161 | #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ | |
162 | ||
163 | #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) | |
164 | #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated | |
165 | * after this time. It should be equal | |
166 | * (or greater than) TCP_TIMEWAIT_LEN | |
167 | * to provide reliability equal to one | |
168 | * provided by timewait state. | |
169 | */ | |
170 | #define TCP_PAWS_WINDOW 1 /* Replay window for per-host | |
171 | * timestamps. It must be less than | |
172 | * minimal timewait lifetime. | |
173 | */ | |
174 | /* | |
175 | * TCP option | |
176 | */ | |
177 | ||
178 | #define TCPOPT_NOP 1 /* Padding */ | |
179 | #define TCPOPT_EOL 0 /* End of options */ | |
180 | #define TCPOPT_MSS 2 /* Segment size negotiating */ | |
181 | #define TCPOPT_WINDOW 3 /* Window scaling */ | |
182 | #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ | |
183 | #define TCPOPT_SACK 5 /* SACK Block */ | |
184 | #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ | |
185 | #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ | |
186 | #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ | |
187 | #define TCPOPT_EXP 254 /* Experimental */ | |
188 | /* Magic number to be after the option value for sharing TCP | |
189 | * experimental options. See draft-ietf-tcpm-experimental-options-00.txt | |
190 | */ | |
191 | #define TCPOPT_FASTOPEN_MAGIC 0xF989 | |
192 | #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 | |
193 | ||
194 | /* | |
195 | * TCP option lengths | |
196 | */ | |
197 | ||
198 | #define TCPOLEN_MSS 4 | |
199 | #define TCPOLEN_WINDOW 3 | |
200 | #define TCPOLEN_SACK_PERM 2 | |
201 | #define TCPOLEN_TIMESTAMP 10 | |
202 | #define TCPOLEN_MD5SIG 18 | |
203 | #define TCPOLEN_FASTOPEN_BASE 2 | |
204 | #define TCPOLEN_EXP_FASTOPEN_BASE 4 | |
205 | #define TCPOLEN_EXP_SMC_BASE 6 | |
206 | ||
207 | /* But this is what stacks really send out. */ | |
208 | #define TCPOLEN_TSTAMP_ALIGNED 12 | |
209 | #define TCPOLEN_WSCALE_ALIGNED 4 | |
210 | #define TCPOLEN_SACKPERM_ALIGNED 4 | |
211 | #define TCPOLEN_SACK_BASE 2 | |
212 | #define TCPOLEN_SACK_BASE_ALIGNED 4 | |
213 | #define TCPOLEN_SACK_PERBLOCK 8 | |
214 | #define TCPOLEN_MD5SIG_ALIGNED 20 | |
215 | #define TCPOLEN_MSS_ALIGNED 4 | |
216 | #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 | |
217 | ||
218 | /* Flags in tp->nonagle */ | |
219 | #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ | |
220 | #define TCP_NAGLE_CORK 2 /* Socket is corked */ | |
221 | #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ | |
222 | ||
223 | /* TCP thin-stream limits */ | |
224 | #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ | |
225 | ||
226 | /* TCP initial congestion window as per rfc6928 */ | |
227 | #define TCP_INIT_CWND 10 | |
228 | ||
229 | /* Bit Flags for sysctl_tcp_fastopen */ | |
230 | #define TFO_CLIENT_ENABLE 1 | |
231 | #define TFO_SERVER_ENABLE 2 | |
232 | #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ | |
233 | ||
234 | /* Accept SYN data w/o any cookie option */ | |
235 | #define TFO_SERVER_COOKIE_NOT_REQD 0x200 | |
236 | ||
237 | /* Force enable TFO on all listeners, i.e., not requiring the | |
238 | * TCP_FASTOPEN socket option. | |
239 | */ | |
240 | #define TFO_SERVER_WO_SOCKOPT1 0x400 | |
241 | ||
242 | ||
243 | /* sysctl variables for tcp */ | |
244 | extern int sysctl_tcp_max_orphans; | |
245 | extern long sysctl_tcp_mem[3]; | |
246 | ||
247 | #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ | |
248 | #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ | |
249 | #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ | |
250 | ||
251 | extern atomic_long_t tcp_memory_allocated; | |
252 | extern struct percpu_counter tcp_sockets_allocated; | |
253 | extern unsigned long tcp_memory_pressure; | |
254 | ||
255 | /* optimized version of sk_under_memory_pressure() for TCP sockets */ | |
256 | static inline bool tcp_under_memory_pressure(const struct sock *sk) | |
257 | { | |
258 | if (mem_cgroup_sockets_enabled && sk->sk_memcg && | |
259 | mem_cgroup_under_socket_pressure(sk->sk_memcg)) | |
260 | return true; | |
261 | ||
262 | return tcp_memory_pressure; | |
263 | } | |
264 | /* | |
265 | * The next routines deal with comparing 32 bit unsigned ints | |
266 | * and worry about wraparound (automatic with unsigned arithmetic). | |
267 | */ | |
268 | ||
269 | static inline bool before(__u32 seq1, __u32 seq2) | |
270 | { | |
271 | return (__s32)(seq1-seq2) < 0; | |
272 | } | |
273 | #define after(seq2, seq1) before(seq1, seq2) | |
274 | ||
275 | /* is s2<=s1<=s3 ? */ | |
276 | static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) | |
277 | { | |
278 | return seq3 - seq2 >= seq1 - seq2; | |
279 | } | |
280 | ||
281 | static inline bool tcp_out_of_memory(struct sock *sk) | |
282 | { | |
283 | if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && | |
284 | sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) | |
285 | return true; | |
286 | return false; | |
287 | } | |
288 | ||
289 | void sk_forced_mem_schedule(struct sock *sk, int size); | |
290 | ||
291 | static inline bool tcp_too_many_orphans(struct sock *sk, int shift) | |
292 | { | |
293 | struct percpu_counter *ocp = sk->sk_prot->orphan_count; | |
294 | int orphans = percpu_counter_read_positive(ocp); | |
295 | ||
296 | if (orphans << shift > sysctl_tcp_max_orphans) { | |
297 | orphans = percpu_counter_sum_positive(ocp); | |
298 | if (orphans << shift > sysctl_tcp_max_orphans) | |
299 | return true; | |
300 | } | |
301 | return false; | |
302 | } | |
303 | ||
304 | bool tcp_check_oom(struct sock *sk, int shift); | |
305 | ||
306 | ||
307 | extern struct proto tcp_prot; | |
308 | ||
309 | #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) | |
310 | #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) | |
311 | #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) | |
312 | #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) | |
313 | ||
314 | void tcp_tasklet_init(void); | |
315 | ||
316 | void tcp_v4_err(struct sk_buff *skb, u32); | |
317 | ||
318 | void tcp_shutdown(struct sock *sk, int how); | |
319 | ||
320 | int tcp_v4_early_demux(struct sk_buff *skb); | |
321 | int tcp_v4_rcv(struct sk_buff *skb); | |
322 | ||
323 | int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); | |
324 | int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); | |
325 | int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); | |
326 | int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, | |
327 | int flags); | |
328 | int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, | |
329 | size_t size, int flags); | |
330 | ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, | |
331 | size_t size, int flags); | |
332 | void tcp_release_cb(struct sock *sk); | |
333 | void tcp_wfree(struct sk_buff *skb); | |
334 | void tcp_write_timer_handler(struct sock *sk); | |
335 | void tcp_delack_timer_handler(struct sock *sk); | |
336 | int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); | |
337 | int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); | |
338 | void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); | |
339 | void tcp_rcv_space_adjust(struct sock *sk); | |
340 | int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); | |
341 | void tcp_twsk_destructor(struct sock *sk); | |
342 | ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, | |
343 | struct pipe_inode_info *pipe, size_t len, | |
344 | unsigned int flags); | |
345 | ||
346 | void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks); | |
347 | static inline void tcp_dec_quickack_mode(struct sock *sk, | |
348 | const unsigned int pkts) | |
349 | { | |
350 | struct inet_connection_sock *icsk = inet_csk(sk); | |
351 | ||
352 | if (icsk->icsk_ack.quick) { | |
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_init_sock(struct sock *sk); | |
392 | void tcp_init_transfer(struct sock *sk, int bpf_op); | |
393 | __poll_t tcp_poll(struct file *file, struct socket *sock, | |
394 | struct poll_table_struct *wait); | |
395 | int tcp_getsockopt(struct sock *sk, int level, int optname, | |
396 | char __user *optval, int __user *optlen); | |
397 | int tcp_setsockopt(struct sock *sk, int level, int optname, | |
398 | char __user *optval, unsigned int optlen); | |
399 | int compat_tcp_getsockopt(struct sock *sk, int level, int optname, | |
400 | char __user *optval, int __user *optlen); | |
401 | int compat_tcp_setsockopt(struct sock *sk, int level, int optname, | |
402 | char __user *optval, unsigned int optlen); | |
403 | void tcp_set_keepalive(struct sock *sk, int val); | |
404 | void tcp_syn_ack_timeout(const struct request_sock *req); | |
405 | int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, | |
406 | int flags, int *addr_len); | |
407 | int tcp_set_rcvlowat(struct sock *sk, int val); | |
408 | void tcp_data_ready(struct sock *sk); | |
409 | int tcp_mmap(struct file *file, struct socket *sock, | |
410 | struct vm_area_struct *vma); | |
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 | * TCP v4 functions exported for the inet6 API | |
418 | */ | |
419 | ||
420 | void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); | |
421 | void tcp_v4_mtu_reduced(struct sock *sk); | |
422 | void tcp_req_err(struct sock *sk, u32 seq, bool abort); | |
423 | int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); | |
424 | struct sock *tcp_create_openreq_child(const struct sock *sk, | |
425 | struct request_sock *req, | |
426 | struct sk_buff *skb); | |
427 | void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); | |
428 | struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, | |
429 | struct request_sock *req, | |
430 | struct dst_entry *dst, | |
431 | struct request_sock *req_unhash, | |
432 | bool *own_req); | |
433 | int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); | |
434 | int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); | |
435 | int tcp_connect(struct sock *sk); | |
436 | enum tcp_synack_type { | |
437 | TCP_SYNACK_NORMAL, | |
438 | TCP_SYNACK_FASTOPEN, | |
439 | TCP_SYNACK_COOKIE, | |
440 | }; | |
441 | struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, | |
442 | struct request_sock *req, | |
443 | struct tcp_fastopen_cookie *foc, | |
444 | enum tcp_synack_type synack_type); | |
445 | int tcp_disconnect(struct sock *sk, int flags); | |
446 | ||
447 | void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); | |
448 | int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); | |
449 | void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); | |
450 | ||
451 | /* From syncookies.c */ | |
452 | struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, | |
453 | struct request_sock *req, | |
454 | struct dst_entry *dst, u32 tsoff); | |
455 | int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, | |
456 | u32 cookie); | |
457 | struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); | |
458 | #ifdef CONFIG_SYN_COOKIES | |
459 | ||
460 | /* Syncookies use a monotonic timer which increments every 60 seconds. | |
461 | * This counter is used both as a hash input and partially encoded into | |
462 | * the cookie value. A cookie is only validated further if the delta | |
463 | * between the current counter value and the encoded one is less than this, | |
464 | * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if | |
465 | * the counter advances immediately after a cookie is generated). | |
466 | */ | |
467 | #define MAX_SYNCOOKIE_AGE 2 | |
468 | #define TCP_SYNCOOKIE_PERIOD (60 * HZ) | |
469 | #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) | |
470 | ||
471 | /* syncookies: remember time of last synqueue overflow | |
472 | * But do not dirty this field too often (once per second is enough) | |
473 | * It is racy as we do not hold a lock, but race is very minor. | |
474 | */ | |
475 | static inline void tcp_synq_overflow(const struct sock *sk) | |
476 | { | |
477 | unsigned int last_overflow; | |
478 | unsigned int now = jiffies; | |
479 | ||
480 | if (sk->sk_reuseport) { | |
481 | struct sock_reuseport *reuse; | |
482 | ||
483 | reuse = rcu_dereference(sk->sk_reuseport_cb); | |
484 | if (likely(reuse)) { | |
485 | last_overflow = READ_ONCE(reuse->synq_overflow_ts); | |
486 | if (time_after32(now, last_overflow + HZ)) | |
487 | WRITE_ONCE(reuse->synq_overflow_ts, now); | |
488 | return; | |
489 | } | |
490 | } | |
491 | ||
492 | last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; | |
493 | if (time_after32(now, last_overflow + HZ)) | |
494 | tcp_sk(sk)->rx_opt.ts_recent_stamp = now; | |
495 | } | |
496 | ||
497 | /* syncookies: no recent synqueue overflow on this listening socket? */ | |
498 | static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) | |
499 | { | |
500 | unsigned int last_overflow; | |
501 | unsigned int now = jiffies; | |
502 | ||
503 | if (sk->sk_reuseport) { | |
504 | struct sock_reuseport *reuse; | |
505 | ||
506 | reuse = rcu_dereference(sk->sk_reuseport_cb); | |
507 | if (likely(reuse)) { | |
508 | last_overflow = READ_ONCE(reuse->synq_overflow_ts); | |
509 | return time_after32(now, last_overflow + | |
510 | TCP_SYNCOOKIE_VALID); | |
511 | } | |
512 | } | |
513 | ||
514 | last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; | |
515 | return time_after32(now, last_overflow + TCP_SYNCOOKIE_VALID); | |
516 | } | |
517 | ||
518 | static inline u32 tcp_cookie_time(void) | |
519 | { | |
520 | u64 val = get_jiffies_64(); | |
521 | ||
522 | do_div(val, TCP_SYNCOOKIE_PERIOD); | |
523 | return val; | |
524 | } | |
525 | ||
526 | u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, | |
527 | u16 *mssp); | |
528 | __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); | |
529 | u64 cookie_init_timestamp(struct request_sock *req); | |
530 | bool cookie_timestamp_decode(const struct net *net, | |
531 | struct tcp_options_received *opt); | |
532 | bool cookie_ecn_ok(const struct tcp_options_received *opt, | |
533 | const struct net *net, const struct dst_entry *dst); | |
534 | ||
535 | /* From net/ipv6/syncookies.c */ | |
536 | int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, | |
537 | u32 cookie); | |
538 | struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); | |
539 | ||
540 | u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, | |
541 | const struct tcphdr *th, u16 *mssp); | |
542 | __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); | |
543 | #endif | |
544 | /* tcp_output.c */ | |
545 | ||
546 | void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, | |
547 | int nonagle); | |
548 | int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); | |
549 | int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); | |
550 | void tcp_retransmit_timer(struct sock *sk); | |
551 | void tcp_xmit_retransmit_queue(struct sock *); | |
552 | void tcp_simple_retransmit(struct sock *); | |
553 | void tcp_enter_recovery(struct sock *sk, bool ece_ack); | |
554 | int tcp_trim_head(struct sock *, struct sk_buff *, u32); | |
555 | enum tcp_queue { | |
556 | TCP_FRAG_IN_WRITE_QUEUE, | |
557 | TCP_FRAG_IN_RTX_QUEUE, | |
558 | }; | |
559 | int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, | |
560 | struct sk_buff *skb, u32 len, | |
561 | unsigned int mss_now, gfp_t gfp); | |
562 | ||
563 | void tcp_send_probe0(struct sock *); | |
564 | void tcp_send_partial(struct sock *); | |
565 | int tcp_write_wakeup(struct sock *, int mib); | |
566 | void tcp_send_fin(struct sock *sk); | |
567 | void tcp_send_active_reset(struct sock *sk, gfp_t priority); | |
568 | int tcp_send_synack(struct sock *); | |
569 | void tcp_push_one(struct sock *, unsigned int mss_now); | |
570 | void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); | |
571 | void tcp_send_ack(struct sock *sk); | |
572 | void tcp_send_delayed_ack(struct sock *sk); | |
573 | void tcp_send_loss_probe(struct sock *sk); | |
574 | bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); | |
575 | void tcp_skb_collapse_tstamp(struct sk_buff *skb, | |
576 | const struct sk_buff *next_skb); | |
577 | ||
578 | /* tcp_input.c */ | |
579 | void tcp_rearm_rto(struct sock *sk); | |
580 | void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); | |
581 | void tcp_reset(struct sock *sk); | |
582 | void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb); | |
583 | void tcp_fin(struct sock *sk); | |
584 | ||
585 | /* tcp_timer.c */ | |
586 | void tcp_init_xmit_timers(struct sock *); | |
587 | static inline void tcp_clear_xmit_timers(struct sock *sk) | |
588 | { | |
589 | if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) | |
590 | __sock_put(sk); | |
591 | ||
592 | if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) | |
593 | __sock_put(sk); | |
594 | ||
595 | inet_csk_clear_xmit_timers(sk); | |
596 | } | |
597 | ||
598 | unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); | |
599 | unsigned int tcp_current_mss(struct sock *sk); | |
600 | ||
601 | /* Bound MSS / TSO packet size with the half of the window */ | |
602 | static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) | |
603 | { | |
604 | int cutoff; | |
605 | ||
606 | /* When peer uses tiny windows, there is no use in packetizing | |
607 | * to sub-MSS pieces for the sake of SWS or making sure there | |
608 | * are enough packets in the pipe for fast recovery. | |
609 | * | |
610 | * On the other hand, for extremely large MSS devices, handling | |
611 | * smaller than MSS windows in this way does make sense. | |
612 | */ | |
613 | if (tp->max_window > TCP_MSS_DEFAULT) | |
614 | cutoff = (tp->max_window >> 1); | |
615 | else | |
616 | cutoff = tp->max_window; | |
617 | ||
618 | if (cutoff && pktsize > cutoff) | |
619 | return max_t(int, cutoff, 68U - tp->tcp_header_len); | |
620 | else | |
621 | return pktsize; | |
622 | } | |
623 | ||
624 | /* tcp.c */ | |
625 | void tcp_get_info(struct sock *, struct tcp_info *); | |
626 | ||
627 | /* Read 'sendfile()'-style from a TCP socket */ | |
628 | int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, | |
629 | sk_read_actor_t recv_actor); | |
630 | ||
631 | void tcp_initialize_rcv_mss(struct sock *sk); | |
632 | ||
633 | int tcp_mtu_to_mss(struct sock *sk, int pmtu); | |
634 | int tcp_mss_to_mtu(struct sock *sk, int mss); | |
635 | void tcp_mtup_init(struct sock *sk); | |
636 | void tcp_init_buffer_space(struct sock *sk); | |
637 | ||
638 | static inline void tcp_bound_rto(const struct sock *sk) | |
639 | { | |
640 | if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) | |
641 | inet_csk(sk)->icsk_rto = TCP_RTO_MAX; | |
642 | } | |
643 | ||
644 | static inline u32 __tcp_set_rto(const struct tcp_sock *tp) | |
645 | { | |
646 | return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); | |
647 | } | |
648 | ||
649 | static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) | |
650 | { | |
651 | tp->pred_flags = htonl((tp->tcp_header_len << 26) | | |
652 | ntohl(TCP_FLAG_ACK) | | |
653 | snd_wnd); | |
654 | } | |
655 | ||
656 | static inline void tcp_fast_path_on(struct tcp_sock *tp) | |
657 | { | |
658 | __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); | |
659 | } | |
660 | ||
661 | static inline void tcp_fast_path_check(struct sock *sk) | |
662 | { | |
663 | struct tcp_sock *tp = tcp_sk(sk); | |
664 | ||
665 | if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && | |
666 | tp->rcv_wnd && | |
667 | atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && | |
668 | !tp->urg_data) | |
669 | tcp_fast_path_on(tp); | |
670 | } | |
671 | ||
672 | /* Compute the actual rto_min value */ | |
673 | static inline u32 tcp_rto_min(struct sock *sk) | |
674 | { | |
675 | const struct dst_entry *dst = __sk_dst_get(sk); | |
676 | u32 rto_min = TCP_RTO_MIN; | |
677 | ||
678 | if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) | |
679 | rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); | |
680 | return rto_min; | |
681 | } | |
682 | ||
683 | static inline u32 tcp_rto_min_us(struct sock *sk) | |
684 | { | |
685 | return jiffies_to_usecs(tcp_rto_min(sk)); | |
686 | } | |
687 | ||
688 | static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) | |
689 | { | |
690 | return dst_metric_locked(dst, RTAX_CC_ALGO); | |
691 | } | |
692 | ||
693 | /* Minimum RTT in usec. ~0 means not available. */ | |
694 | static inline u32 tcp_min_rtt(const struct tcp_sock *tp) | |
695 | { | |
696 | return minmax_get(&tp->rtt_min); | |
697 | } | |
698 | ||
699 | /* Compute the actual receive window we are currently advertising. | |
700 | * Rcv_nxt can be after the window if our peer push more data | |
701 | * than the offered window. | |
702 | */ | |
703 | static inline u32 tcp_receive_window(const struct tcp_sock *tp) | |
704 | { | |
705 | s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; | |
706 | ||
707 | if (win < 0) | |
708 | win = 0; | |
709 | return (u32) win; | |
710 | } | |
711 | ||
712 | /* Choose a new window, without checks for shrinking, and without | |
713 | * scaling applied to the result. The caller does these things | |
714 | * if necessary. This is a "raw" window selection. | |
715 | */ | |
716 | u32 __tcp_select_window(struct sock *sk); | |
717 | ||
718 | void tcp_send_window_probe(struct sock *sk); | |
719 | ||
720 | /* TCP uses 32bit jiffies to save some space. | |
721 | * Note that this is different from tcp_time_stamp, which | |
722 | * historically has been the same until linux-4.13. | |
723 | */ | |
724 | #define tcp_jiffies32 ((u32)jiffies) | |
725 | ||
726 | /* | |
727 | * Deliver a 32bit value for TCP timestamp option (RFC 7323) | |
728 | * It is no longer tied to jiffies, but to 1 ms clock. | |
729 | * Note: double check if you want to use tcp_jiffies32 instead of this. | |
730 | */ | |
731 | #define TCP_TS_HZ 1000 | |
732 | ||
733 | static inline u64 tcp_clock_ns(void) | |
734 | { | |
735 | return ktime_get_tai_ns(); | |
736 | } | |
737 | ||
738 | static inline u64 tcp_clock_us(void) | |
739 | { | |
740 | return div_u64(tcp_clock_ns(), NSEC_PER_USEC); | |
741 | } | |
742 | ||
743 | /* This should only be used in contexts where tp->tcp_mstamp is up to date */ | |
744 | static inline u32 tcp_time_stamp(const struct tcp_sock *tp) | |
745 | { | |
746 | return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); | |
747 | } | |
748 | ||
749 | /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ | |
750 | static inline u32 tcp_time_stamp_raw(void) | |
751 | { | |
752 | return div_u64(tcp_clock_ns(), NSEC_PER_SEC / TCP_TS_HZ); | |
753 | } | |
754 | ||
755 | void tcp_mstamp_refresh(struct tcp_sock *tp); | |
756 | ||
757 | static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) | |
758 | { | |
759 | return max_t(s64, t1 - t0, 0); | |
760 | } | |
761 | ||
762 | static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) | |
763 | { | |
764 | return div_u64(skb->skb_mstamp_ns, NSEC_PER_SEC / TCP_TS_HZ); | |
765 | } | |
766 | ||
767 | /* provide the departure time in us unit */ | |
768 | static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) | |
769 | { | |
770 | return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); | |
771 | } | |
772 | ||
773 | ||
774 | #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) | |
775 | ||
776 | #define TCPHDR_FIN 0x01 | |
777 | #define TCPHDR_SYN 0x02 | |
778 | #define TCPHDR_RST 0x04 | |
779 | #define TCPHDR_PSH 0x08 | |
780 | #define TCPHDR_ACK 0x10 | |
781 | #define TCPHDR_URG 0x20 | |
782 | #define TCPHDR_ECE 0x40 | |
783 | #define TCPHDR_CWR 0x80 | |
784 | ||
785 | #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) | |
786 | ||
787 | /* This is what the send packet queuing engine uses to pass | |
788 | * TCP per-packet control information to the transmission code. | |
789 | * We also store the host-order sequence numbers in here too. | |
790 | * This is 44 bytes if IPV6 is enabled. | |
791 | * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. | |
792 | */ | |
793 | struct tcp_skb_cb { | |
794 | __u32 seq; /* Starting sequence number */ | |
795 | __u32 end_seq; /* SEQ + FIN + SYN + datalen */ | |
796 | union { | |
797 | /* Note : tcp_tw_isn is used in input path only | |
798 | * (isn chosen by tcp_timewait_state_process()) | |
799 | * | |
800 | * tcp_gso_segs/size are used in write queue only, | |
801 | * cf tcp_skb_pcount()/tcp_skb_mss() | |
802 | */ | |
803 | __u32 tcp_tw_isn; | |
804 | struct { | |
805 | u16 tcp_gso_segs; | |
806 | u16 tcp_gso_size; | |
807 | }; | |
808 | }; | |
809 | __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ | |
810 | ||
811 | __u8 sacked; /* State flags for SACK. */ | |
812 | #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ | |
813 | #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ | |
814 | #define TCPCB_LOST 0x04 /* SKB is lost */ | |
815 | #define TCPCB_TAGBITS 0x07 /* All tag bits */ | |
816 | #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ | |
817 | #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ | |
818 | #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ | |
819 | TCPCB_REPAIRED) | |
820 | ||
821 | __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ | |
822 | __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ | |
823 | eor:1, /* Is skb MSG_EOR marked? */ | |
824 | has_rxtstamp:1, /* SKB has a RX timestamp */ | |
825 | unused:5; | |
826 | __u32 ack_seq; /* Sequence number ACK'd */ | |
827 | union { | |
828 | struct { | |
829 | /* There is space for up to 24 bytes */ | |
830 | __u32 in_flight:30,/* Bytes in flight at transmit */ | |
831 | is_app_limited:1, /* cwnd not fully used? */ | |
832 | unused:1; | |
833 | /* pkts S/ACKed so far upon tx of skb, incl retrans: */ | |
834 | __u32 delivered; | |
835 | /* start of send pipeline phase */ | |
836 | u64 first_tx_mstamp; | |
837 | /* when we reached the "delivered" count */ | |
838 | u64 delivered_mstamp; | |
839 | } tx; /* only used for outgoing skbs */ | |
840 | union { | |
841 | struct inet_skb_parm h4; | |
842 | #if IS_ENABLED(CONFIG_IPV6) | |
843 | struct inet6_skb_parm h6; | |
844 | #endif | |
845 | } header; /* For incoming skbs */ | |
846 | struct { | |
847 | __u32 flags; | |
848 | struct sock *sk_redir; | |
849 | void *data_end; | |
850 | } bpf; | |
851 | }; | |
852 | }; | |
853 | ||
854 | #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) | |
855 | ||
856 | static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb) | |
857 | { | |
858 | TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb); | |
859 | } | |
860 | ||
861 | #if IS_ENABLED(CONFIG_IPV6) | |
862 | /* This is the variant of inet6_iif() that must be used by TCP, | |
863 | * as TCP moves IP6CB into a different location in skb->cb[] | |
864 | */ | |
865 | static inline int tcp_v6_iif(const struct sk_buff *skb) | |
866 | { | |
867 | return TCP_SKB_CB(skb)->header.h6.iif; | |
868 | } | |
869 | ||
870 | static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) | |
871 | { | |
872 | bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); | |
873 | ||
874 | return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; | |
875 | } | |
876 | ||
877 | /* TCP_SKB_CB reference means this can not be used from early demux */ | |
878 | static inline int tcp_v6_sdif(const struct sk_buff *skb) | |
879 | { | |
880 | #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) | |
881 | if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) | |
882 | return TCP_SKB_CB(skb)->header.h6.iif; | |
883 | #endif | |
884 | return 0; | |
885 | } | |
886 | #endif | |
887 | ||
888 | static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb) | |
889 | { | |
890 | #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) | |
891 | if (!net->ipv4.sysctl_tcp_l3mdev_accept && | |
892 | skb && ipv4_l3mdev_skb(IPCB(skb)->flags)) | |
893 | return true; | |
894 | #endif | |
895 | return false; | |
896 | } | |
897 | ||
898 | /* TCP_SKB_CB reference means this can not be used from early demux */ | |
899 | static inline int tcp_v4_sdif(struct sk_buff *skb) | |
900 | { | |
901 | #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) | |
902 | if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) | |
903 | return TCP_SKB_CB(skb)->header.h4.iif; | |
904 | #endif | |
905 | return 0; | |
906 | } | |
907 | ||
908 | /* Due to TSO, an SKB can be composed of multiple actual | |
909 | * packets. To keep these tracked properly, we use this. | |
910 | */ | |
911 | static inline int tcp_skb_pcount(const struct sk_buff *skb) | |
912 | { | |
913 | return TCP_SKB_CB(skb)->tcp_gso_segs; | |
914 | } | |
915 | ||
916 | static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) | |
917 | { | |
918 | TCP_SKB_CB(skb)->tcp_gso_segs = segs; | |
919 | } | |
920 | ||
921 | static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) | |
922 | { | |
923 | TCP_SKB_CB(skb)->tcp_gso_segs += segs; | |
924 | } | |
925 | ||
926 | /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ | |
927 | static inline int tcp_skb_mss(const struct sk_buff *skb) | |
928 | { | |
929 | return TCP_SKB_CB(skb)->tcp_gso_size; | |
930 | } | |
931 | ||
932 | static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) | |
933 | { | |
934 | return likely(!TCP_SKB_CB(skb)->eor); | |
935 | } | |
936 | ||
937 | /* Events passed to congestion control interface */ | |
938 | enum tcp_ca_event { | |
939 | CA_EVENT_TX_START, /* first transmit when no packets in flight */ | |
940 | CA_EVENT_CWND_RESTART, /* congestion window restart */ | |
941 | CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ | |
942 | CA_EVENT_LOSS, /* loss timeout */ | |
943 | CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ | |
944 | CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ | |
945 | }; | |
946 | ||
947 | /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ | |
948 | enum tcp_ca_ack_event_flags { | |
949 | CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ | |
950 | CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ | |
951 | CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ | |
952 | }; | |
953 | ||
954 | /* | |
955 | * Interface for adding new TCP congestion control handlers | |
956 | */ | |
957 | #define TCP_CA_NAME_MAX 16 | |
958 | #define TCP_CA_MAX 128 | |
959 | #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) | |
960 | ||
961 | #define TCP_CA_UNSPEC 0 | |
962 | ||
963 | /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ | |
964 | #define TCP_CONG_NON_RESTRICTED 0x1 | |
965 | /* Requires ECN/ECT set on all packets */ | |
966 | #define TCP_CONG_NEEDS_ECN 0x2 | |
967 | ||
968 | union tcp_cc_info; | |
969 | ||
970 | struct ack_sample { | |
971 | u32 pkts_acked; | |
972 | s32 rtt_us; | |
973 | u32 in_flight; | |
974 | }; | |
975 | ||
976 | /* A rate sample measures the number of (original/retransmitted) data | |
977 | * packets delivered "delivered" over an interval of time "interval_us". | |
978 | * The tcp_rate.c code fills in the rate sample, and congestion | |
979 | * control modules that define a cong_control function to run at the end | |
980 | * of ACK processing can optionally chose to consult this sample when | |
981 | * setting cwnd and pacing rate. | |
982 | * A sample is invalid if "delivered" or "interval_us" is negative. | |
983 | */ | |
984 | struct rate_sample { | |
985 | u64 prior_mstamp; /* starting timestamp for interval */ | |
986 | u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ | |
987 | s32 delivered; /* number of packets delivered over interval */ | |
988 | long interval_us; /* time for tp->delivered to incr "delivered" */ | |
989 | u32 snd_interval_us; /* snd interval for delivered packets */ | |
990 | u32 rcv_interval_us; /* rcv interval for delivered packets */ | |
991 | long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ | |
992 | int losses; /* number of packets marked lost upon ACK */ | |
993 | u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ | |
994 | u32 prior_in_flight; /* in flight before this ACK */ | |
995 | bool is_app_limited; /* is sample from packet with bubble in pipe? */ | |
996 | bool is_retrans; /* is sample from retransmission? */ | |
997 | bool is_ack_delayed; /* is this (likely) a delayed ACK? */ | |
998 | }; | |
999 | ||
1000 | struct tcp_congestion_ops { | |
1001 | struct list_head list; | |
1002 | u32 key; | |
1003 | u32 flags; | |
1004 | ||
1005 | /* initialize private data (optional) */ | |
1006 | void (*init)(struct sock *sk); | |
1007 | /* cleanup private data (optional) */ | |
1008 | void (*release)(struct sock *sk); | |
1009 | ||
1010 | /* return slow start threshold (required) */ | |
1011 | u32 (*ssthresh)(struct sock *sk); | |
1012 | /* do new cwnd calculation (required) */ | |
1013 | void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); | |
1014 | /* call before changing ca_state (optional) */ | |
1015 | void (*set_state)(struct sock *sk, u8 new_state); | |
1016 | /* call when cwnd event occurs (optional) */ | |
1017 | void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); | |
1018 | /* call when ack arrives (optional) */ | |
1019 | void (*in_ack_event)(struct sock *sk, u32 flags); | |
1020 | /* new value of cwnd after loss (required) */ | |
1021 | u32 (*undo_cwnd)(struct sock *sk); | |
1022 | /* hook for packet ack accounting (optional) */ | |
1023 | void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); | |
1024 | /* override sysctl_tcp_min_tso_segs */ | |
1025 | u32 (*min_tso_segs)(struct sock *sk); | |
1026 | /* returns the multiplier used in tcp_sndbuf_expand (optional) */ | |
1027 | u32 (*sndbuf_expand)(struct sock *sk); | |
1028 | /* call when packets are delivered to update cwnd and pacing rate, | |
1029 | * after all the ca_state processing. (optional) | |
1030 | */ | |
1031 | void (*cong_control)(struct sock *sk, const struct rate_sample *rs); | |
1032 | /* get info for inet_diag (optional) */ | |
1033 | size_t (*get_info)(struct sock *sk, u32 ext, int *attr, | |
1034 | union tcp_cc_info *info); | |
1035 | ||
1036 | char name[TCP_CA_NAME_MAX]; | |
1037 | struct module *owner; | |
1038 | }; | |
1039 | ||
1040 | int tcp_register_congestion_control(struct tcp_congestion_ops *type); | |
1041 | void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); | |
1042 | ||
1043 | void tcp_assign_congestion_control(struct sock *sk); | |
1044 | void tcp_init_congestion_control(struct sock *sk); | |
1045 | void tcp_cleanup_congestion_control(struct sock *sk); | |
1046 | int tcp_set_default_congestion_control(struct net *net, const char *name); | |
1047 | void tcp_get_default_congestion_control(struct net *net, char *name); | |
1048 | void tcp_get_available_congestion_control(char *buf, size_t len); | |
1049 | void tcp_get_allowed_congestion_control(char *buf, size_t len); | |
1050 | int tcp_set_allowed_congestion_control(char *allowed); | |
1051 | int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, bool reinit); | |
1052 | u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); | |
1053 | void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); | |
1054 | ||
1055 | u32 tcp_reno_ssthresh(struct sock *sk); | |
1056 | u32 tcp_reno_undo_cwnd(struct sock *sk); | |
1057 | void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); | |
1058 | extern struct tcp_congestion_ops tcp_reno; | |
1059 | ||
1060 | struct tcp_congestion_ops *tcp_ca_find_key(u32 key); | |
1061 | u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); | |
1062 | #ifdef CONFIG_INET | |
1063 | char *tcp_ca_get_name_by_key(u32 key, char *buffer); | |
1064 | #else | |
1065 | static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) | |
1066 | { | |
1067 | return NULL; | |
1068 | } | |
1069 | #endif | |
1070 | ||
1071 | static inline bool tcp_ca_needs_ecn(const struct sock *sk) | |
1072 | { | |
1073 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
1074 | ||
1075 | return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; | |
1076 | } | |
1077 | ||
1078 | static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) | |
1079 | { | |
1080 | struct inet_connection_sock *icsk = inet_csk(sk); | |
1081 | ||
1082 | if (icsk->icsk_ca_ops->set_state) | |
1083 | icsk->icsk_ca_ops->set_state(sk, ca_state); | |
1084 | icsk->icsk_ca_state = ca_state; | |
1085 | } | |
1086 | ||
1087 | static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) | |
1088 | { | |
1089 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
1090 | ||
1091 | if (icsk->icsk_ca_ops->cwnd_event) | |
1092 | icsk->icsk_ca_ops->cwnd_event(sk, event); | |
1093 | } | |
1094 | ||
1095 | /* From tcp_rate.c */ | |
1096 | void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); | |
1097 | void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, | |
1098 | struct rate_sample *rs); | |
1099 | void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, | |
1100 | bool is_sack_reneg, struct rate_sample *rs); | |
1101 | void tcp_rate_check_app_limited(struct sock *sk); | |
1102 | ||
1103 | /* These functions determine how the current flow behaves in respect of SACK | |
1104 | * handling. SACK is negotiated with the peer, and therefore it can vary | |
1105 | * between different flows. | |
1106 | * | |
1107 | * tcp_is_sack - SACK enabled | |
1108 | * tcp_is_reno - No SACK | |
1109 | */ | |
1110 | static inline int tcp_is_sack(const struct tcp_sock *tp) | |
1111 | { | |
1112 | return tp->rx_opt.sack_ok; | |
1113 | } | |
1114 | ||
1115 | static inline bool tcp_is_reno(const struct tcp_sock *tp) | |
1116 | { | |
1117 | return !tcp_is_sack(tp); | |
1118 | } | |
1119 | ||
1120 | static inline unsigned int tcp_left_out(const struct tcp_sock *tp) | |
1121 | { | |
1122 | return tp->sacked_out + tp->lost_out; | |
1123 | } | |
1124 | ||
1125 | /* This determines how many packets are "in the network" to the best | |
1126 | * of our knowledge. In many cases it is conservative, but where | |
1127 | * detailed information is available from the receiver (via SACK | |
1128 | * blocks etc.) we can make more aggressive calculations. | |
1129 | * | |
1130 | * Use this for decisions involving congestion control, use just | |
1131 | * tp->packets_out to determine if the send queue is empty or not. | |
1132 | * | |
1133 | * Read this equation as: | |
1134 | * | |
1135 | * "Packets sent once on transmission queue" MINUS | |
1136 | * "Packets left network, but not honestly ACKed yet" PLUS | |
1137 | * "Packets fast retransmitted" | |
1138 | */ | |
1139 | static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) | |
1140 | { | |
1141 | return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; | |
1142 | } | |
1143 | ||
1144 | #define TCP_INFINITE_SSTHRESH 0x7fffffff | |
1145 | ||
1146 | static inline bool tcp_in_slow_start(const struct tcp_sock *tp) | |
1147 | { | |
1148 | return tp->snd_cwnd < tp->snd_ssthresh; | |
1149 | } | |
1150 | ||
1151 | static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) | |
1152 | { | |
1153 | return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; | |
1154 | } | |
1155 | ||
1156 | static inline bool tcp_in_cwnd_reduction(const struct sock *sk) | |
1157 | { | |
1158 | return (TCPF_CA_CWR | TCPF_CA_Recovery) & | |
1159 | (1 << inet_csk(sk)->icsk_ca_state); | |
1160 | } | |
1161 | ||
1162 | /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. | |
1163 | * The exception is cwnd reduction phase, when cwnd is decreasing towards | |
1164 | * ssthresh. | |
1165 | */ | |
1166 | static inline __u32 tcp_current_ssthresh(const struct sock *sk) | |
1167 | { | |
1168 | const struct tcp_sock *tp = tcp_sk(sk); | |
1169 | ||
1170 | if (tcp_in_cwnd_reduction(sk)) | |
1171 | return tp->snd_ssthresh; | |
1172 | else | |
1173 | return max(tp->snd_ssthresh, | |
1174 | ((tp->snd_cwnd >> 1) + | |
1175 | (tp->snd_cwnd >> 2))); | |
1176 | } | |
1177 | ||
1178 | /* Use define here intentionally to get WARN_ON location shown at the caller */ | |
1179 | #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) | |
1180 | ||
1181 | void tcp_enter_cwr(struct sock *sk); | |
1182 | __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); | |
1183 | ||
1184 | /* The maximum number of MSS of available cwnd for which TSO defers | |
1185 | * sending if not using sysctl_tcp_tso_win_divisor. | |
1186 | */ | |
1187 | static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) | |
1188 | { | |
1189 | return 3; | |
1190 | } | |
1191 | ||
1192 | /* Returns end sequence number of the receiver's advertised window */ | |
1193 | static inline u32 tcp_wnd_end(const struct tcp_sock *tp) | |
1194 | { | |
1195 | return tp->snd_una + tp->snd_wnd; | |
1196 | } | |
1197 | ||
1198 | /* We follow the spirit of RFC2861 to validate cwnd but implement a more | |
1199 | * flexible approach. The RFC suggests cwnd should not be raised unless | |
1200 | * it was fully used previously. And that's exactly what we do in | |
1201 | * congestion avoidance mode. But in slow start we allow cwnd to grow | |
1202 | * as long as the application has used half the cwnd. | |
1203 | * Example : | |
1204 | * cwnd is 10 (IW10), but application sends 9 frames. | |
1205 | * We allow cwnd to reach 18 when all frames are ACKed. | |
1206 | * This check is safe because it's as aggressive as slow start which already | |
1207 | * risks 100% overshoot. The advantage is that we discourage application to | |
1208 | * either send more filler packets or data to artificially blow up the cwnd | |
1209 | * usage, and allow application-limited process to probe bw more aggressively. | |
1210 | */ | |
1211 | static inline bool tcp_is_cwnd_limited(const struct sock *sk) | |
1212 | { | |
1213 | const struct tcp_sock *tp = tcp_sk(sk); | |
1214 | ||
1215 | /* If in slow start, ensure cwnd grows to twice what was ACKed. */ | |
1216 | if (tcp_in_slow_start(tp)) | |
1217 | return tp->snd_cwnd < 2 * tp->max_packets_out; | |
1218 | ||
1219 | return tp->is_cwnd_limited; | |
1220 | } | |
1221 | ||
1222 | /* BBR congestion control needs pacing. | |
1223 | * Same remark for SO_MAX_PACING_RATE. | |
1224 | * sch_fq packet scheduler is efficiently handling pacing, | |
1225 | * but is not always installed/used. | |
1226 | * Return true if TCP stack should pace packets itself. | |
1227 | */ | |
1228 | static inline bool tcp_needs_internal_pacing(const struct sock *sk) | |
1229 | { | |
1230 | return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; | |
1231 | } | |
1232 | ||
1233 | /* Something is really bad, we could not queue an additional packet, | |
1234 | * because qdisc is full or receiver sent a 0 window. | |
1235 | * We do not want to add fuel to the fire, or abort too early, | |
1236 | * so make sure the timer we arm now is at least 200ms in the future, | |
1237 | * regardless of current icsk_rto value (as it could be ~2ms) | |
1238 | */ | |
1239 | static inline unsigned long tcp_probe0_base(const struct sock *sk) | |
1240 | { | |
1241 | return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); | |
1242 | } | |
1243 | ||
1244 | /* Variant of inet_csk_rto_backoff() used for zero window probes */ | |
1245 | static inline unsigned long tcp_probe0_when(const struct sock *sk, | |
1246 | unsigned long max_when) | |
1247 | { | |
1248 | u64 when = (u64)tcp_probe0_base(sk) << inet_csk(sk)->icsk_backoff; | |
1249 | ||
1250 | return (unsigned long)min_t(u64, when, max_when); | |
1251 | } | |
1252 | ||
1253 | static inline void tcp_check_probe_timer(struct sock *sk) | |
1254 | { | |
1255 | if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) | |
1256 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, | |
1257 | tcp_probe0_base(sk), TCP_RTO_MAX); | |
1258 | } | |
1259 | ||
1260 | static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) | |
1261 | { | |
1262 | tp->snd_wl1 = seq; | |
1263 | } | |
1264 | ||
1265 | static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) | |
1266 | { | |
1267 | tp->snd_wl1 = seq; | |
1268 | } | |
1269 | ||
1270 | /* | |
1271 | * Calculate(/check) TCP checksum | |
1272 | */ | |
1273 | static inline __sum16 tcp_v4_check(int len, __be32 saddr, | |
1274 | __be32 daddr, __wsum base) | |
1275 | { | |
1276 | return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); | |
1277 | } | |
1278 | ||
1279 | static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) | |
1280 | { | |
1281 | return __skb_checksum_complete(skb); | |
1282 | } | |
1283 | ||
1284 | static inline bool tcp_checksum_complete(struct sk_buff *skb) | |
1285 | { | |
1286 | return !skb_csum_unnecessary(skb) && | |
1287 | __tcp_checksum_complete(skb); | |
1288 | } | |
1289 | ||
1290 | bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); | |
1291 | int tcp_filter(struct sock *sk, struct sk_buff *skb); | |
1292 | ||
1293 | #undef STATE_TRACE | |
1294 | ||
1295 | #ifdef STATE_TRACE | |
1296 | static const char *statename[]={ | |
1297 | "Unused","Established","Syn Sent","Syn Recv", | |
1298 | "Fin Wait 1","Fin Wait 2","Time Wait", "Close", | |
1299 | "Close Wait","Last ACK","Listen","Closing" | |
1300 | }; | |
1301 | #endif | |
1302 | void tcp_set_state(struct sock *sk, int state); | |
1303 | ||
1304 | void tcp_done(struct sock *sk); | |
1305 | ||
1306 | int tcp_abort(struct sock *sk, int err); | |
1307 | ||
1308 | static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) | |
1309 | { | |
1310 | rx_opt->dsack = 0; | |
1311 | rx_opt->num_sacks = 0; | |
1312 | } | |
1313 | ||
1314 | u32 tcp_default_init_rwnd(u32 mss); | |
1315 | void tcp_cwnd_restart(struct sock *sk, s32 delta); | |
1316 | ||
1317 | static inline void tcp_slow_start_after_idle_check(struct sock *sk) | |
1318 | { | |
1319 | const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; | |
1320 | struct tcp_sock *tp = tcp_sk(sk); | |
1321 | s32 delta; | |
1322 | ||
1323 | if (!sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle || tp->packets_out || | |
1324 | ca_ops->cong_control) | |
1325 | return; | |
1326 | delta = tcp_jiffies32 - tp->lsndtime; | |
1327 | if (delta > inet_csk(sk)->icsk_rto) | |
1328 | tcp_cwnd_restart(sk, delta); | |
1329 | } | |
1330 | ||
1331 | /* Determine a window scaling and initial window to offer. */ | |
1332 | void tcp_select_initial_window(const struct sock *sk, int __space, | |
1333 | __u32 mss, __u32 *rcv_wnd, | |
1334 | __u32 *window_clamp, int wscale_ok, | |
1335 | __u8 *rcv_wscale, __u32 init_rcv_wnd); | |
1336 | ||
1337 | static inline int tcp_win_from_space(const struct sock *sk, int space) | |
1338 | { | |
1339 | int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; | |
1340 | ||
1341 | return tcp_adv_win_scale <= 0 ? | |
1342 | (space>>(-tcp_adv_win_scale)) : | |
1343 | space - (space>>tcp_adv_win_scale); | |
1344 | } | |
1345 | ||
1346 | /* Note: caller must be prepared to deal with negative returns */ | |
1347 | static inline int tcp_space(const struct sock *sk) | |
1348 | { | |
1349 | return tcp_win_from_space(sk, sk->sk_rcvbuf - | |
1350 | atomic_read(&sk->sk_rmem_alloc)); | |
1351 | } | |
1352 | ||
1353 | static inline int tcp_full_space(const struct sock *sk) | |
1354 | { | |
1355 | return tcp_win_from_space(sk, sk->sk_rcvbuf); | |
1356 | } | |
1357 | ||
1358 | extern void tcp_openreq_init_rwin(struct request_sock *req, | |
1359 | const struct sock *sk_listener, | |
1360 | const struct dst_entry *dst); | |
1361 | ||
1362 | void tcp_enter_memory_pressure(struct sock *sk); | |
1363 | void tcp_leave_memory_pressure(struct sock *sk); | |
1364 | ||
1365 | static inline int keepalive_intvl_when(const struct tcp_sock *tp) | |
1366 | { | |
1367 | struct net *net = sock_net((struct sock *)tp); | |
1368 | ||
1369 | return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl; | |
1370 | } | |
1371 | ||
1372 | static inline int keepalive_time_when(const struct tcp_sock *tp) | |
1373 | { | |
1374 | struct net *net = sock_net((struct sock *)tp); | |
1375 | ||
1376 | return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time; | |
1377 | } | |
1378 | ||
1379 | static inline int keepalive_probes(const struct tcp_sock *tp) | |
1380 | { | |
1381 | struct net *net = sock_net((struct sock *)tp); | |
1382 | ||
1383 | return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes; | |
1384 | } | |
1385 | ||
1386 | static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) | |
1387 | { | |
1388 | const struct inet_connection_sock *icsk = &tp->inet_conn; | |
1389 | ||
1390 | return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, | |
1391 | tcp_jiffies32 - tp->rcv_tstamp); | |
1392 | } | |
1393 | ||
1394 | static inline int tcp_fin_time(const struct sock *sk) | |
1395 | { | |
1396 | int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout; | |
1397 | const int rto = inet_csk(sk)->icsk_rto; | |
1398 | ||
1399 | if (fin_timeout < (rto << 2) - (rto >> 1)) | |
1400 | fin_timeout = (rto << 2) - (rto >> 1); | |
1401 | ||
1402 | return fin_timeout; | |
1403 | } | |
1404 | ||
1405 | static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, | |
1406 | int paws_win) | |
1407 | { | |
1408 | if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) | |
1409 | return true; | |
1410 | if (unlikely(!time_before32(ktime_get_seconds(), | |
1411 | rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) | |
1412 | return true; | |
1413 | /* | |
1414 | * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, | |
1415 | * then following tcp messages have valid values. Ignore 0 value, | |
1416 | * or else 'negative' tsval might forbid us to accept their packets. | |
1417 | */ | |
1418 | if (!rx_opt->ts_recent) | |
1419 | return true; | |
1420 | return false; | |
1421 | } | |
1422 | ||
1423 | static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, | |
1424 | int rst) | |
1425 | { | |
1426 | if (tcp_paws_check(rx_opt, 0)) | |
1427 | return false; | |
1428 | ||
1429 | /* RST segments are not recommended to carry timestamp, | |
1430 | and, if they do, it is recommended to ignore PAWS because | |
1431 | "their cleanup function should take precedence over timestamps." | |
1432 | Certainly, it is mistake. It is necessary to understand the reasons | |
1433 | of this constraint to relax it: if peer reboots, clock may go | |
1434 | out-of-sync and half-open connections will not be reset. | |
1435 | Actually, the problem would be not existing if all | |
1436 | the implementations followed draft about maintaining clock | |
1437 | via reboots. Linux-2.2 DOES NOT! | |
1438 | ||
1439 | However, we can relax time bounds for RST segments to MSL. | |
1440 | */ | |
1441 | if (rst && !time_before32(ktime_get_seconds(), | |
1442 | rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) | |
1443 | return false; | |
1444 | return true; | |
1445 | } | |
1446 | ||
1447 | bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, | |
1448 | int mib_idx, u32 *last_oow_ack_time); | |
1449 | ||
1450 | static inline void tcp_mib_init(struct net *net) | |
1451 | { | |
1452 | /* See RFC 2012 */ | |
1453 | TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); | |
1454 | TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); | |
1455 | TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); | |
1456 | TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); | |
1457 | } | |
1458 | ||
1459 | /* from STCP */ | |
1460 | static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) | |
1461 | { | |
1462 | tp->lost_skb_hint = NULL; | |
1463 | } | |
1464 | ||
1465 | static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) | |
1466 | { | |
1467 | tcp_clear_retrans_hints_partial(tp); | |
1468 | tp->retransmit_skb_hint = NULL; | |
1469 | } | |
1470 | ||
1471 | union tcp_md5_addr { | |
1472 | struct in_addr a4; | |
1473 | #if IS_ENABLED(CONFIG_IPV6) | |
1474 | struct in6_addr a6; | |
1475 | #endif | |
1476 | }; | |
1477 | ||
1478 | /* - key database */ | |
1479 | struct tcp_md5sig_key { | |
1480 | struct hlist_node node; | |
1481 | u8 keylen; | |
1482 | u8 family; /* AF_INET or AF_INET6 */ | |
1483 | union tcp_md5_addr addr; | |
1484 | u8 prefixlen; | |
1485 | u8 key[TCP_MD5SIG_MAXKEYLEN]; | |
1486 | struct rcu_head rcu; | |
1487 | }; | |
1488 | ||
1489 | /* - sock block */ | |
1490 | struct tcp_md5sig_info { | |
1491 | struct hlist_head head; | |
1492 | struct rcu_head rcu; | |
1493 | }; | |
1494 | ||
1495 | /* - pseudo header */ | |
1496 | struct tcp4_pseudohdr { | |
1497 | __be32 saddr; | |
1498 | __be32 daddr; | |
1499 | __u8 pad; | |
1500 | __u8 protocol; | |
1501 | __be16 len; | |
1502 | }; | |
1503 | ||
1504 | struct tcp6_pseudohdr { | |
1505 | struct in6_addr saddr; | |
1506 | struct in6_addr daddr; | |
1507 | __be32 len; | |
1508 | __be32 protocol; /* including padding */ | |
1509 | }; | |
1510 | ||
1511 | union tcp_md5sum_block { | |
1512 | struct tcp4_pseudohdr ip4; | |
1513 | #if IS_ENABLED(CONFIG_IPV6) | |
1514 | struct tcp6_pseudohdr ip6; | |
1515 | #endif | |
1516 | }; | |
1517 | ||
1518 | /* - pool: digest algorithm, hash description and scratch buffer */ | |
1519 | struct tcp_md5sig_pool { | |
1520 | struct ahash_request *md5_req; | |
1521 | void *scratch; | |
1522 | }; | |
1523 | ||
1524 | /* - functions */ | |
1525 | int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, | |
1526 | const struct sock *sk, const struct sk_buff *skb); | |
1527 | int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, | |
1528 | int family, u8 prefixlen, const u8 *newkey, u8 newkeylen, | |
1529 | gfp_t gfp); | |
1530 | int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, | |
1531 | int family, u8 prefixlen); | |
1532 | struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, | |
1533 | const struct sock *addr_sk); | |
1534 | ||
1535 | #ifdef CONFIG_TCP_MD5SIG | |
1536 | struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk, | |
1537 | const union tcp_md5_addr *addr, | |
1538 | int family); | |
1539 | #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) | |
1540 | #else | |
1541 | static inline struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk, | |
1542 | const union tcp_md5_addr *addr, | |
1543 | int family) | |
1544 | { | |
1545 | return NULL; | |
1546 | } | |
1547 | #define tcp_twsk_md5_key(twsk) NULL | |
1548 | #endif | |
1549 | ||
1550 | bool tcp_alloc_md5sig_pool(void); | |
1551 | ||
1552 | struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); | |
1553 | static inline void tcp_put_md5sig_pool(void) | |
1554 | { | |
1555 | local_bh_enable(); | |
1556 | } | |
1557 | ||
1558 | int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, | |
1559 | unsigned int header_len); | |
1560 | int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, | |
1561 | const struct tcp_md5sig_key *key); | |
1562 | ||
1563 | /* From tcp_fastopen.c */ | |
1564 | void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, | |
1565 | struct tcp_fastopen_cookie *cookie); | |
1566 | void tcp_fastopen_cache_set(struct sock *sk, u16 mss, | |
1567 | struct tcp_fastopen_cookie *cookie, bool syn_lost, | |
1568 | u16 try_exp); | |
1569 | struct tcp_fastopen_request { | |
1570 | /* Fast Open cookie. Size 0 means a cookie request */ | |
1571 | struct tcp_fastopen_cookie cookie; | |
1572 | struct msghdr *data; /* data in MSG_FASTOPEN */ | |
1573 | size_t size; | |
1574 | int copied; /* queued in tcp_connect() */ | |
1575 | }; | |
1576 | void tcp_free_fastopen_req(struct tcp_sock *tp); | |
1577 | void tcp_fastopen_destroy_cipher(struct sock *sk); | |
1578 | void tcp_fastopen_ctx_destroy(struct net *net); | |
1579 | int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, | |
1580 | void *key, unsigned int len); | |
1581 | void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); | |
1582 | struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, | |
1583 | struct request_sock *req, | |
1584 | struct tcp_fastopen_cookie *foc, | |
1585 | const struct dst_entry *dst); | |
1586 | void tcp_fastopen_init_key_once(struct net *net); | |
1587 | bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, | |
1588 | struct tcp_fastopen_cookie *cookie); | |
1589 | bool tcp_fastopen_defer_connect(struct sock *sk, int *err); | |
1590 | #define TCP_FASTOPEN_KEY_LENGTH 16 | |
1591 | ||
1592 | /* Fastopen key context */ | |
1593 | struct tcp_fastopen_context { | |
1594 | struct crypto_cipher *tfm; | |
1595 | __u8 key[TCP_FASTOPEN_KEY_LENGTH]; | |
1596 | struct rcu_head rcu; | |
1597 | }; | |
1598 | ||
1599 | extern unsigned int sysctl_tcp_fastopen_blackhole_timeout; | |
1600 | void tcp_fastopen_active_disable(struct sock *sk); | |
1601 | bool tcp_fastopen_active_should_disable(struct sock *sk); | |
1602 | void tcp_fastopen_active_disable_ofo_check(struct sock *sk); | |
1603 | void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); | |
1604 | ||
1605 | /* Latencies incurred by various limits for a sender. They are | |
1606 | * chronograph-like stats that are mutually exclusive. | |
1607 | */ | |
1608 | enum tcp_chrono { | |
1609 | TCP_CHRONO_UNSPEC, | |
1610 | TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ | |
1611 | TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ | |
1612 | TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ | |
1613 | __TCP_CHRONO_MAX, | |
1614 | }; | |
1615 | ||
1616 | void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); | |
1617 | void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); | |
1618 | ||
1619 | /* This helper is needed, because skb->tcp_tsorted_anchor uses | |
1620 | * the same memory storage than skb->destructor/_skb_refdst | |
1621 | */ | |
1622 | static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) | |
1623 | { | |
1624 | skb->destructor = NULL; | |
1625 | skb->_skb_refdst = 0UL; | |
1626 | } | |
1627 | ||
1628 | #define tcp_skb_tsorted_save(skb) { \ | |
1629 | unsigned long _save = skb->_skb_refdst; \ | |
1630 | skb->_skb_refdst = 0UL; | |
1631 | ||
1632 | #define tcp_skb_tsorted_restore(skb) \ | |
1633 | skb->_skb_refdst = _save; \ | |
1634 | } | |
1635 | ||
1636 | void tcp_write_queue_purge(struct sock *sk); | |
1637 | ||
1638 | static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) | |
1639 | { | |
1640 | return skb_rb_first(&sk->tcp_rtx_queue); | |
1641 | } | |
1642 | ||
1643 | static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) | |
1644 | { | |
1645 | return skb_peek(&sk->sk_write_queue); | |
1646 | } | |
1647 | ||
1648 | static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) | |
1649 | { | |
1650 | return skb_peek_tail(&sk->sk_write_queue); | |
1651 | } | |
1652 | ||
1653 | #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ | |
1654 | skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) | |
1655 | ||
1656 | static inline struct sk_buff *tcp_send_head(const struct sock *sk) | |
1657 | { | |
1658 | return skb_peek(&sk->sk_write_queue); | |
1659 | } | |
1660 | ||
1661 | static inline bool tcp_skb_is_last(const struct sock *sk, | |
1662 | const struct sk_buff *skb) | |
1663 | { | |
1664 | return skb_queue_is_last(&sk->sk_write_queue, skb); | |
1665 | } | |
1666 | ||
1667 | static inline bool tcp_write_queue_empty(const struct sock *sk) | |
1668 | { | |
1669 | return skb_queue_empty(&sk->sk_write_queue); | |
1670 | } | |
1671 | ||
1672 | static inline bool tcp_rtx_queue_empty(const struct sock *sk) | |
1673 | { | |
1674 | return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); | |
1675 | } | |
1676 | ||
1677 | static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) | |
1678 | { | |
1679 | return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); | |
1680 | } | |
1681 | ||
1682 | static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked) | |
1683 | { | |
1684 | if (tcp_write_queue_empty(sk)) | |
1685 | tcp_chrono_stop(sk, TCP_CHRONO_BUSY); | |
1686 | } | |
1687 | ||
1688 | static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) | |
1689 | { | |
1690 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1691 | } | |
1692 | ||
1693 | static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) | |
1694 | { | |
1695 | __tcp_add_write_queue_tail(sk, skb); | |
1696 | ||
1697 | /* Queue it, remembering where we must start sending. */ | |
1698 | if (sk->sk_write_queue.next == skb) | |
1699 | tcp_chrono_start(sk, TCP_CHRONO_BUSY); | |
1700 | } | |
1701 | ||
1702 | /* Insert new before skb on the write queue of sk. */ | |
1703 | static inline void tcp_insert_write_queue_before(struct sk_buff *new, | |
1704 | struct sk_buff *skb, | |
1705 | struct sock *sk) | |
1706 | { | |
1707 | __skb_queue_before(&sk->sk_write_queue, skb, new); | |
1708 | } | |
1709 | ||
1710 | static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) | |
1711 | { | |
1712 | tcp_skb_tsorted_anchor_cleanup(skb); | |
1713 | __skb_unlink(skb, &sk->sk_write_queue); | |
1714 | } | |
1715 | ||
1716 | void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); | |
1717 | ||
1718 | static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) | |
1719 | { | |
1720 | tcp_skb_tsorted_anchor_cleanup(skb); | |
1721 | rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); | |
1722 | } | |
1723 | ||
1724 | static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) | |
1725 | { | |
1726 | list_del(&skb->tcp_tsorted_anchor); | |
1727 | tcp_rtx_queue_unlink(skb, sk); | |
1728 | sk_wmem_free_skb(sk, skb); | |
1729 | } | |
1730 | ||
1731 | static inline void tcp_push_pending_frames(struct sock *sk) | |
1732 | { | |
1733 | if (tcp_send_head(sk)) { | |
1734 | struct tcp_sock *tp = tcp_sk(sk); | |
1735 | ||
1736 | __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); | |
1737 | } | |
1738 | } | |
1739 | ||
1740 | /* Start sequence of the skb just after the highest skb with SACKed | |
1741 | * bit, valid only if sacked_out > 0 or when the caller has ensured | |
1742 | * validity by itself. | |
1743 | */ | |
1744 | static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) | |
1745 | { | |
1746 | if (!tp->sacked_out) | |
1747 | return tp->snd_una; | |
1748 | ||
1749 | if (tp->highest_sack == NULL) | |
1750 | return tp->snd_nxt; | |
1751 | ||
1752 | return TCP_SKB_CB(tp->highest_sack)->seq; | |
1753 | } | |
1754 | ||
1755 | static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) | |
1756 | { | |
1757 | tcp_sk(sk)->highest_sack = skb_rb_next(skb); | |
1758 | } | |
1759 | ||
1760 | static inline struct sk_buff *tcp_highest_sack(struct sock *sk) | |
1761 | { | |
1762 | return tcp_sk(sk)->highest_sack; | |
1763 | } | |
1764 | ||
1765 | static inline void tcp_highest_sack_reset(struct sock *sk) | |
1766 | { | |
1767 | tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); | |
1768 | } | |
1769 | ||
1770 | /* Called when old skb is about to be deleted and replaced by new skb */ | |
1771 | static inline void tcp_highest_sack_replace(struct sock *sk, | |
1772 | struct sk_buff *old, | |
1773 | struct sk_buff *new) | |
1774 | { | |
1775 | if (old == tcp_highest_sack(sk)) | |
1776 | tcp_sk(sk)->highest_sack = new; | |
1777 | } | |
1778 | ||
1779 | /* This helper checks if socket has IP_TRANSPARENT set */ | |
1780 | static inline bool inet_sk_transparent(const struct sock *sk) | |
1781 | { | |
1782 | switch (sk->sk_state) { | |
1783 | case TCP_TIME_WAIT: | |
1784 | return inet_twsk(sk)->tw_transparent; | |
1785 | case TCP_NEW_SYN_RECV: | |
1786 | return inet_rsk(inet_reqsk(sk))->no_srccheck; | |
1787 | } | |
1788 | return inet_sk(sk)->transparent; | |
1789 | } | |
1790 | ||
1791 | /* Determines whether this is a thin stream (which may suffer from | |
1792 | * increased latency). Used to trigger latency-reducing mechanisms. | |
1793 | */ | |
1794 | static inline bool tcp_stream_is_thin(struct tcp_sock *tp) | |
1795 | { | |
1796 | return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); | |
1797 | } | |
1798 | ||
1799 | /* /proc */ | |
1800 | enum tcp_seq_states { | |
1801 | TCP_SEQ_STATE_LISTENING, | |
1802 | TCP_SEQ_STATE_ESTABLISHED, | |
1803 | }; | |
1804 | ||
1805 | void *tcp_seq_start(struct seq_file *seq, loff_t *pos); | |
1806 | void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); | |
1807 | void tcp_seq_stop(struct seq_file *seq, void *v); | |
1808 | ||
1809 | struct tcp_seq_afinfo { | |
1810 | sa_family_t family; | |
1811 | }; | |
1812 | ||
1813 | struct tcp_iter_state { | |
1814 | struct seq_net_private p; | |
1815 | enum tcp_seq_states state; | |
1816 | struct sock *syn_wait_sk; | |
1817 | int bucket, offset, sbucket, num; | |
1818 | loff_t last_pos; | |
1819 | }; | |
1820 | ||
1821 | extern struct request_sock_ops tcp_request_sock_ops; | |
1822 | extern struct request_sock_ops tcp6_request_sock_ops; | |
1823 | ||
1824 | void tcp_v4_destroy_sock(struct sock *sk); | |
1825 | ||
1826 | struct sk_buff *tcp_gso_segment(struct sk_buff *skb, | |
1827 | netdev_features_t features); | |
1828 | struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); | |
1829 | int tcp_gro_complete(struct sk_buff *skb); | |
1830 | ||
1831 | void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); | |
1832 | ||
1833 | static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) | |
1834 | { | |
1835 | struct net *net = sock_net((struct sock *)tp); | |
1836 | return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat; | |
1837 | } | |
1838 | ||
1839 | static inline bool tcp_stream_memory_free(const struct sock *sk) | |
1840 | { | |
1841 | const struct tcp_sock *tp = tcp_sk(sk); | |
1842 | u32 notsent_bytes = tp->write_seq - tp->snd_nxt; | |
1843 | ||
1844 | return notsent_bytes < tcp_notsent_lowat(tp); | |
1845 | } | |
1846 | ||
1847 | #ifdef CONFIG_PROC_FS | |
1848 | int tcp4_proc_init(void); | |
1849 | void tcp4_proc_exit(void); | |
1850 | #endif | |
1851 | ||
1852 | int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); | |
1853 | int tcp_conn_request(struct request_sock_ops *rsk_ops, | |
1854 | const struct tcp_request_sock_ops *af_ops, | |
1855 | struct sock *sk, struct sk_buff *skb); | |
1856 | ||
1857 | /* TCP af-specific functions */ | |
1858 | struct tcp_sock_af_ops { | |
1859 | #ifdef CONFIG_TCP_MD5SIG | |
1860 | struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, | |
1861 | const struct sock *addr_sk); | |
1862 | int (*calc_md5_hash)(char *location, | |
1863 | const struct tcp_md5sig_key *md5, | |
1864 | const struct sock *sk, | |
1865 | const struct sk_buff *skb); | |
1866 | int (*md5_parse)(struct sock *sk, | |
1867 | int optname, | |
1868 | char __user *optval, | |
1869 | int optlen); | |
1870 | #endif | |
1871 | }; | |
1872 | ||
1873 | struct tcp_request_sock_ops { | |
1874 | u16 mss_clamp; | |
1875 | #ifdef CONFIG_TCP_MD5SIG | |
1876 | struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, | |
1877 | const struct sock *addr_sk); | |
1878 | int (*calc_md5_hash) (char *location, | |
1879 | const struct tcp_md5sig_key *md5, | |
1880 | const struct sock *sk, | |
1881 | const struct sk_buff *skb); | |
1882 | #endif | |
1883 | void (*init_req)(struct request_sock *req, | |
1884 | const struct sock *sk_listener, | |
1885 | struct sk_buff *skb); | |
1886 | #ifdef CONFIG_SYN_COOKIES | |
1887 | __u32 (*cookie_init_seq)(const struct sk_buff *skb, | |
1888 | __u16 *mss); | |
1889 | #endif | |
1890 | struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl, | |
1891 | const struct request_sock *req); | |
1892 | u32 (*init_seq)(const struct sk_buff *skb); | |
1893 | u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); | |
1894 | int (*send_synack)(const struct sock *sk, struct dst_entry *dst, | |
1895 | struct flowi *fl, struct request_sock *req, | |
1896 | struct tcp_fastopen_cookie *foc, | |
1897 | enum tcp_synack_type synack_type); | |
1898 | }; | |
1899 | ||
1900 | #ifdef CONFIG_SYN_COOKIES | |
1901 | static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, | |
1902 | const struct sock *sk, struct sk_buff *skb, | |
1903 | __u16 *mss) | |
1904 | { | |
1905 | tcp_synq_overflow(sk); | |
1906 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); | |
1907 | return ops->cookie_init_seq(skb, mss); | |
1908 | } | |
1909 | #else | |
1910 | static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, | |
1911 | const struct sock *sk, struct sk_buff *skb, | |
1912 | __u16 *mss) | |
1913 | { | |
1914 | return 0; | |
1915 | } | |
1916 | #endif | |
1917 | ||
1918 | int tcpv4_offload_init(void); | |
1919 | ||
1920 | void tcp_v4_init(void); | |
1921 | void tcp_init(void); | |
1922 | ||
1923 | /* tcp_recovery.c */ | |
1924 | void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); | |
1925 | void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); | |
1926 | extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, | |
1927 | u32 reo_wnd); | |
1928 | extern void tcp_rack_mark_lost(struct sock *sk); | |
1929 | extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, | |
1930 | u64 xmit_time); | |
1931 | extern void tcp_rack_reo_timeout(struct sock *sk); | |
1932 | extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); | |
1933 | ||
1934 | /* At how many usecs into the future should the RTO fire? */ | |
1935 | static inline s64 tcp_rto_delta_us(const struct sock *sk) | |
1936 | { | |
1937 | const struct sk_buff *skb = tcp_rtx_queue_head(sk); | |
1938 | u32 rto = inet_csk(sk)->icsk_rto; | |
1939 | u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); | |
1940 | ||
1941 | return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; | |
1942 | } | |
1943 | ||
1944 | /* | |
1945 | * Save and compile IPv4 options, return a pointer to it | |
1946 | */ | |
1947 | static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, | |
1948 | struct sk_buff *skb) | |
1949 | { | |
1950 | const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; | |
1951 | struct ip_options_rcu *dopt = NULL; | |
1952 | ||
1953 | if (opt->optlen) { | |
1954 | int opt_size = sizeof(*dopt) + opt->optlen; | |
1955 | ||
1956 | dopt = kmalloc(opt_size, GFP_ATOMIC); | |
1957 | if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { | |
1958 | kfree(dopt); | |
1959 | dopt = NULL; | |
1960 | } | |
1961 | } | |
1962 | return dopt; | |
1963 | } | |
1964 | ||
1965 | /* locally generated TCP pure ACKs have skb->truesize == 2 | |
1966 | * (check tcp_send_ack() in net/ipv4/tcp_output.c ) | |
1967 | * This is much faster than dissecting the packet to find out. | |
1968 | * (Think of GRE encapsulations, IPv4, IPv6, ...) | |
1969 | */ | |
1970 | static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) | |
1971 | { | |
1972 | return skb->truesize == 2; | |
1973 | } | |
1974 | ||
1975 | static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) | |
1976 | { | |
1977 | skb->truesize = 2; | |
1978 | } | |
1979 | ||
1980 | static inline int tcp_inq(struct sock *sk) | |
1981 | { | |
1982 | struct tcp_sock *tp = tcp_sk(sk); | |
1983 | int answ; | |
1984 | ||
1985 | if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { | |
1986 | answ = 0; | |
1987 | } else if (sock_flag(sk, SOCK_URGINLINE) || | |
1988 | !tp->urg_data || | |
1989 | before(tp->urg_seq, tp->copied_seq) || | |
1990 | !before(tp->urg_seq, tp->rcv_nxt)) { | |
1991 | ||
1992 | answ = tp->rcv_nxt - tp->copied_seq; | |
1993 | ||
1994 | /* Subtract 1, if FIN was received */ | |
1995 | if (answ && sock_flag(sk, SOCK_DONE)) | |
1996 | answ--; | |
1997 | } else { | |
1998 | answ = tp->urg_seq - tp->copied_seq; | |
1999 | } | |
2000 | ||
2001 | return answ; | |
2002 | } | |
2003 | ||
2004 | int tcp_peek_len(struct socket *sock); | |
2005 | ||
2006 | static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) | |
2007 | { | |
2008 | u16 segs_in; | |
2009 | ||
2010 | segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); | |
2011 | tp->segs_in += segs_in; | |
2012 | if (skb->len > tcp_hdrlen(skb)) | |
2013 | tp->data_segs_in += segs_in; | |
2014 | } | |
2015 | ||
2016 | /* | |
2017 | * TCP listen path runs lockless. | |
2018 | * We forced "struct sock" to be const qualified to make sure | |
2019 | * we don't modify one of its field by mistake. | |
2020 | * Here, we increment sk_drops which is an atomic_t, so we can safely | |
2021 | * make sock writable again. | |
2022 | */ | |
2023 | static inline void tcp_listendrop(const struct sock *sk) | |
2024 | { | |
2025 | atomic_inc(&((struct sock *)sk)->sk_drops); | |
2026 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); | |
2027 | } | |
2028 | ||
2029 | enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); | |
2030 | ||
2031 | /* | |
2032 | * Interface for adding Upper Level Protocols over TCP | |
2033 | */ | |
2034 | ||
2035 | #define TCP_ULP_NAME_MAX 16 | |
2036 | #define TCP_ULP_MAX 128 | |
2037 | #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) | |
2038 | ||
2039 | enum { | |
2040 | TCP_ULP_TLS, | |
2041 | TCP_ULP_BPF, | |
2042 | }; | |
2043 | ||
2044 | struct tcp_ulp_ops { | |
2045 | struct list_head list; | |
2046 | ||
2047 | /* initialize ulp */ | |
2048 | int (*init)(struct sock *sk); | |
2049 | /* cleanup ulp */ | |
2050 | void (*release)(struct sock *sk); | |
2051 | ||
2052 | int uid; | |
2053 | char name[TCP_ULP_NAME_MAX]; | |
2054 | bool user_visible; | |
2055 | struct module *owner; | |
2056 | }; | |
2057 | int tcp_register_ulp(struct tcp_ulp_ops *type); | |
2058 | void tcp_unregister_ulp(struct tcp_ulp_ops *type); | |
2059 | int tcp_set_ulp(struct sock *sk, const char *name); | |
2060 | int tcp_set_ulp_id(struct sock *sk, const int ulp); | |
2061 | void tcp_get_available_ulp(char *buf, size_t len); | |
2062 | void tcp_cleanup_ulp(struct sock *sk); | |
2063 | ||
2064 | #define MODULE_ALIAS_TCP_ULP(name) \ | |
2065 | __MODULE_INFO(alias, alias_userspace, name); \ | |
2066 | __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) | |
2067 | ||
2068 | /* Call BPF_SOCK_OPS program that returns an int. If the return value | |
2069 | * is < 0, then the BPF op failed (for example if the loaded BPF | |
2070 | * program does not support the chosen operation or there is no BPF | |
2071 | * program loaded). | |
2072 | */ | |
2073 | #ifdef CONFIG_BPF | |
2074 | static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) | |
2075 | { | |
2076 | struct bpf_sock_ops_kern sock_ops; | |
2077 | int ret; | |
2078 | ||
2079 | memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); | |
2080 | if (sk_fullsock(sk)) { | |
2081 | sock_ops.is_fullsock = 1; | |
2082 | sock_owned_by_me(sk); | |
2083 | } | |
2084 | ||
2085 | sock_ops.sk = sk; | |
2086 | sock_ops.op = op; | |
2087 | if (nargs > 0) | |
2088 | memcpy(sock_ops.args, args, nargs * sizeof(*args)); | |
2089 | ||
2090 | ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); | |
2091 | if (ret == 0) | |
2092 | ret = sock_ops.reply; | |
2093 | else | |
2094 | ret = -1; | |
2095 | return ret; | |
2096 | } | |
2097 | ||
2098 | static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) | |
2099 | { | |
2100 | u32 args[2] = {arg1, arg2}; | |
2101 | ||
2102 | return tcp_call_bpf(sk, op, 2, args); | |
2103 | } | |
2104 | ||
2105 | static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, | |
2106 | u32 arg3) | |
2107 | { | |
2108 | u32 args[3] = {arg1, arg2, arg3}; | |
2109 | ||
2110 | return tcp_call_bpf(sk, op, 3, args); | |
2111 | } | |
2112 | ||
2113 | #else | |
2114 | static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) | |
2115 | { | |
2116 | return -EPERM; | |
2117 | } | |
2118 | ||
2119 | static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) | |
2120 | { | |
2121 | return -EPERM; | |
2122 | } | |
2123 | ||
2124 | static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, | |
2125 | u32 arg3) | |
2126 | { | |
2127 | return -EPERM; | |
2128 | } | |
2129 | ||
2130 | #endif | |
2131 | ||
2132 | static inline u32 tcp_timeout_init(struct sock *sk) | |
2133 | { | |
2134 | int timeout; | |
2135 | ||
2136 | timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); | |
2137 | ||
2138 | if (timeout <= 0) | |
2139 | timeout = TCP_TIMEOUT_INIT; | |
2140 | return timeout; | |
2141 | } | |
2142 | ||
2143 | static inline u32 tcp_rwnd_init_bpf(struct sock *sk) | |
2144 | { | |
2145 | int rwnd; | |
2146 | ||
2147 | rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); | |
2148 | ||
2149 | if (rwnd < 0) | |
2150 | rwnd = 0; | |
2151 | return rwnd; | |
2152 | } | |
2153 | ||
2154 | static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) | |
2155 | { | |
2156 | return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); | |
2157 | } | |
2158 | ||
2159 | #if IS_ENABLED(CONFIG_SMC) | |
2160 | extern struct static_key_false tcp_have_smc; | |
2161 | #endif | |
2162 | ||
2163 | #if IS_ENABLED(CONFIG_TLS_DEVICE) | |
2164 | void clean_acked_data_enable(struct inet_connection_sock *icsk, | |
2165 | void (*cad)(struct sock *sk, u32 ack_seq)); | |
2166 | void clean_acked_data_disable(struct inet_connection_sock *icsk); | |
2167 | ||
2168 | #endif | |
2169 | ||
2170 | #endif /* _TCP_H */ |