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/cryptohash.h> 27 #include <linux/kref.h> 28 #include <linux/ktime.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 43 #include <linux/seq_file.h> 44 #include <linux/memcontrol.h> 45 #include <linux/bpf-cgroup.h> 46 #include <linux/siphash.h> 47 48 extern struct inet_hashinfo tcp_hashinfo; 49 50 extern struct percpu_counter tcp_orphan_count; 51 void tcp_time_wait(struct sock *sk, int state, int timeo); 52 53 #define MAX_TCP_HEADER (128 + MAX_HEADER) 54 #define MAX_TCP_OPTION_SPACE 40 55 #define TCP_MIN_SND_MSS 48 56 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 57 58 /* 59 * Never offer a window over 32767 without using window scaling. Some 60 * poor stacks do signed 16bit maths! 61 */ 62 #define MAX_TCP_WINDOW 32767U 63 64 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 65 #define TCP_MIN_MSS 88U 66 67 /* The initial MTU to use for probing */ 68 #define TCP_BASE_MSS 1024 69 70 /* probing interval, default to 10 minutes as per RFC4821 */ 71 #define TCP_PROBE_INTERVAL 600 72 73 /* Specify interval when tcp mtu probing will stop */ 74 #define TCP_PROBE_THRESHOLD 8 75 76 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 77 #define TCP_FASTRETRANS_THRESH 3 78 79 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 80 #define TCP_MAX_QUICKACKS 16U 81 82 /* Maximal number of window scale according to RFC1323 */ 83 #define TCP_MAX_WSCALE 14U 84 85 /* urg_data states */ 86 #define TCP_URG_VALID 0x0100 87 #define TCP_URG_NOTYET 0x0200 88 #define TCP_URG_READ 0x0400 89 90 #define TCP_RETR1 3 /* 91 * This is how many retries it does before it 92 * tries to figure out if the gateway is 93 * down. Minimal RFC value is 3; it corresponds 94 * to ~3sec-8min depending on RTO. 95 */ 96 97 #define TCP_RETR2 15 /* 98 * This should take at least 99 * 90 minutes to time out. 100 * RFC1122 says that the limit is 100 sec. 101 * 15 is ~13-30min depending on RTO. 102 */ 103 104 #define TCP_SYN_RETRIES 6 /* This is how many retries are done 105 * when active opening a connection. 106 * RFC1122 says the minimum retry MUST 107 * be at least 180secs. Nevertheless 108 * this value is corresponding to 109 * 63secs of retransmission with the 110 * current initial RTO. 111 */ 112 113 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done 114 * when passive opening a connection. 115 * This is corresponding to 31secs of 116 * retransmission with the current 117 * initial RTO. 118 */ 119 120 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 121 * state, about 60 seconds */ 122 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 123 /* BSD style FIN_WAIT2 deadlock breaker. 124 * It used to be 3min, new value is 60sec, 125 * to combine FIN-WAIT-2 timeout with 126 * TIME-WAIT timer. 127 */ 128 129 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 130 #if HZ >= 100 131 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 132 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 133 #else 134 #define TCP_DELACK_MIN 4U 135 #define TCP_ATO_MIN 4U 136 #endif 137 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 138 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 139 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ 140 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 141 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 142 * used as a fallback RTO for the 143 * initial data transmission if no 144 * valid RTT sample has been acquired, 145 * most likely due to retrans in 3WHS. 146 */ 147 148 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 149 * for local resources. 150 */ 151 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 152 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 153 #define TCP_KEEPALIVE_INTVL (75*HZ) 154 155 #define MAX_TCP_KEEPIDLE 32767 156 #define MAX_TCP_KEEPINTVL 32767 157 #define MAX_TCP_KEEPCNT 127 158 #define MAX_TCP_SYNCNT 127 159 160 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 161 162 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 163 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 164 * after this time. It should be equal 165 * (or greater than) TCP_TIMEWAIT_LEN 166 * to provide reliability equal to one 167 * provided by timewait state. 168 */ 169 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 170 * timestamps. It must be less than 171 * minimal timewait lifetime. 172 */ 173 /* 174 * TCP option 175 */ 176 177 #define TCPOPT_NOP 1 /* Padding */ 178 #define TCPOPT_EOL 0 /* End of options */ 179 #define TCPOPT_MSS 2 /* Segment size negotiating */ 180 #define TCPOPT_WINDOW 3 /* Window scaling */ 181 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 182 #define TCPOPT_SACK 5 /* SACK Block */ 183 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 184 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 185 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 186 #define TCPOPT_EXP 254 /* Experimental */ 187 /* Magic number to be after the option value for sharing TCP 188 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 189 */ 190 #define TCPOPT_FASTOPEN_MAGIC 0xF989 191 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 192 193 /* 194 * TCP option lengths 195 */ 196 197 #define TCPOLEN_MSS 4 198 #define TCPOLEN_WINDOW 3 199 #define TCPOLEN_SACK_PERM 2 200 #define TCPOLEN_TIMESTAMP 10 201 #define TCPOLEN_MD5SIG 18 202 #define TCPOLEN_FASTOPEN_BASE 2 203 #define TCPOLEN_EXP_FASTOPEN_BASE 4 204 #define TCPOLEN_EXP_SMC_BASE 6 205 206 /* But this is what stacks really send out. */ 207 #define TCPOLEN_TSTAMP_ALIGNED 12 208 #define TCPOLEN_WSCALE_ALIGNED 4 209 #define TCPOLEN_SACKPERM_ALIGNED 4 210 #define TCPOLEN_SACK_BASE 2 211 #define TCPOLEN_SACK_BASE_ALIGNED 4 212 #define TCPOLEN_SACK_PERBLOCK 8 213 #define TCPOLEN_MD5SIG_ALIGNED 20 214 #define TCPOLEN_MSS_ALIGNED 4 215 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 216 217 /* Flags in tp->nonagle */ 218 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 219 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 220 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 221 222 /* TCP thin-stream limits */ 223 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 224 225 /* TCP initial congestion window as per rfc6928 */ 226 #define TCP_INIT_CWND 10 227 228 /* Bit Flags for sysctl_tcp_fastopen */ 229 #define TFO_CLIENT_ENABLE 1 230 #define TFO_SERVER_ENABLE 2 231 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 232 233 /* Accept SYN data w/o any cookie option */ 234 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 235 236 /* Force enable TFO on all listeners, i.e., not requiring the 237 * TCP_FASTOPEN socket option. 238 */ 239 #define TFO_SERVER_WO_SOCKOPT1 0x400 240 241 242 /* sysctl variables for tcp */ 243 extern int sysctl_tcp_max_orphans; 244 extern long sysctl_tcp_mem[3]; 245 246 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 247 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 248 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 249 250 extern atomic_long_t tcp_memory_allocated; 251 extern struct percpu_counter tcp_sockets_allocated; 252 extern unsigned long tcp_memory_pressure; 253 254 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 255 static inline bool tcp_under_memory_pressure(const struct sock *sk) 256 { 257 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 258 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 259 return true; 260 261 return READ_ONCE(tcp_memory_pressure); 262 } 263 /* 264 * The next routines deal with comparing 32 bit unsigned ints 265 * and worry about wraparound (automatic with unsigned arithmetic). 266 */ 267 268 static inline bool before(__u32 seq1, __u32 seq2) 269 { 270 return (__s32)(seq1-seq2) < 0; 271 } 272 #define after(seq2, seq1) before(seq1, seq2) 273 274 /* is s2<=s1<=s3 ? */ 275 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 276 { 277 return seq3 - seq2 >= seq1 - seq2; 278 } 279 280 static inline bool tcp_out_of_memory(struct sock *sk) 281 { 282 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 283 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 284 return true; 285 return false; 286 } 287 288 void sk_forced_mem_schedule(struct sock *sk, int size); 289 290 static inline bool tcp_too_many_orphans(struct sock *sk, int shift) 291 { 292 struct percpu_counter *ocp = sk->sk_prot->orphan_count; 293 int orphans = percpu_counter_read_positive(ocp); 294 295 if (orphans << shift > sysctl_tcp_max_orphans) { 296 orphans = percpu_counter_sum_positive(ocp); 297 if (orphans << shift > sysctl_tcp_max_orphans) 298 return true; 299 } 300 return false; 301 } 302 303 bool tcp_check_oom(struct sock *sk, int shift); 304 305 306 extern struct proto tcp_prot; 307 308 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 309 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 310 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 311 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 312 313 void tcp_tasklet_init(void); 314 315 int tcp_v4_err(struct sk_buff *skb, u32); 316 317 void tcp_shutdown(struct sock *sk, int how); 318 319 int tcp_v4_early_demux(struct sk_buff *skb); 320 int tcp_v4_rcv(struct sk_buff *skb); 321 322 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 323 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 324 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 325 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, 326 int flags); 327 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, 328 size_t size, int flags); 329 ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 330 size_t size, int flags); 331 void tcp_release_cb(struct sock *sk); 332 void tcp_wfree(struct sk_buff *skb); 333 void tcp_write_timer_handler(struct sock *sk); 334 void tcp_delack_timer_handler(struct sock *sk); 335 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); 336 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 337 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 338 void tcp_rcv_space_adjust(struct sock *sk); 339 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 340 void tcp_twsk_destructor(struct sock *sk); 341 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 342 struct pipe_inode_info *pipe, size_t len, 343 unsigned int flags); 344 345 void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks); 346 static inline void tcp_dec_quickack_mode(struct sock *sk, 347 const unsigned int pkts) 348 { 349 struct inet_connection_sock *icsk = inet_csk(sk); 350 351 if (icsk->icsk_ack.quick) { 352 if (pkts >= icsk->icsk_ack.quick) { 353 icsk->icsk_ack.quick = 0; 354 /* Leaving quickack mode we deflate ATO. */ 355 icsk->icsk_ack.ato = TCP_ATO_MIN; 356 } else 357 icsk->icsk_ack.quick -= pkts; 358 } 359 } 360 361 #define TCP_ECN_OK 1 362 #define TCP_ECN_QUEUE_CWR 2 363 #define TCP_ECN_DEMAND_CWR 4 364 #define TCP_ECN_SEEN 8 365 366 enum tcp_tw_status { 367 TCP_TW_SUCCESS = 0, 368 TCP_TW_RST = 1, 369 TCP_TW_ACK = 2, 370 TCP_TW_SYN = 3 371 }; 372 373 374 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 375 struct sk_buff *skb, 376 const struct tcphdr *th); 377 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 378 struct request_sock *req, bool fastopen, 379 bool *lost_race); 380 int tcp_child_process(struct sock *parent, struct sock *child, 381 struct sk_buff *skb); 382 void tcp_enter_loss(struct sock *sk); 383 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int flag); 384 void tcp_clear_retrans(struct tcp_sock *tp); 385 void tcp_update_metrics(struct sock *sk); 386 void tcp_init_metrics(struct sock *sk); 387 void tcp_metrics_init(void); 388 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 389 void tcp_close(struct sock *sk, long timeout); 390 void tcp_init_sock(struct sock *sk); 391 void tcp_init_transfer(struct sock *sk, int bpf_op); 392 __poll_t tcp_poll(struct file *file, struct socket *sock, 393 struct poll_table_struct *wait); 394 int tcp_getsockopt(struct sock *sk, int level, int optname, 395 char __user *optval, int __user *optlen); 396 int tcp_setsockopt(struct sock *sk, int level, int optname, 397 char __user *optval, unsigned int optlen); 398 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 399 char __user *optval, int __user *optlen); 400 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 401 char __user *optval, unsigned int optlen); 402 void tcp_set_keepalive(struct sock *sk, int val); 403 void tcp_syn_ack_timeout(const struct request_sock *req); 404 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 405 int flags, int *addr_len); 406 int tcp_set_rcvlowat(struct sock *sk, int val); 407 void tcp_data_ready(struct sock *sk); 408 #ifdef CONFIG_MMU 409 int tcp_mmap(struct file *file, struct socket *sock, 410 struct vm_area_struct *vma); 411 #endif 412 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 413 struct tcp_options_received *opt_rx, 414 int estab, struct tcp_fastopen_cookie *foc); 415 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); 416 417 /* 418 * BPF SKB-less helpers 419 */ 420 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 421 struct tcphdr *th, u32 *cookie); 422 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 423 struct tcphdr *th, u32 *cookie); 424 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 425 const struct tcp_request_sock_ops *af_ops, 426 struct sock *sk, struct tcphdr *th); 427 /* 428 * TCP v4 functions exported for the inet6 API 429 */ 430 431 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 432 void tcp_v4_mtu_reduced(struct sock *sk); 433 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 434 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 435 struct sock *tcp_create_openreq_child(const struct sock *sk, 436 struct request_sock *req, 437 struct sk_buff *skb); 438 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 439 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 440 struct request_sock *req, 441 struct dst_entry *dst, 442 struct request_sock *req_unhash, 443 bool *own_req); 444 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 445 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 446 int tcp_connect(struct sock *sk); 447 enum tcp_synack_type { 448 TCP_SYNACK_NORMAL, 449 TCP_SYNACK_FASTOPEN, 450 TCP_SYNACK_COOKIE, 451 }; 452 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 453 struct request_sock *req, 454 struct tcp_fastopen_cookie *foc, 455 enum tcp_synack_type synack_type); 456 int tcp_disconnect(struct sock *sk, int flags); 457 458 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 459 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 460 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 461 462 /* From syncookies.c */ 463 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 464 struct request_sock *req, 465 struct dst_entry *dst, u32 tsoff); 466 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, 467 u32 cookie); 468 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 469 #ifdef CONFIG_SYN_COOKIES 470 471 /* Syncookies use a monotonic timer which increments every 60 seconds. 472 * This counter is used both as a hash input and partially encoded into 473 * the cookie value. A cookie is only validated further if the delta 474 * between the current counter value and the encoded one is less than this, 475 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 476 * the counter advances immediately after a cookie is generated). 477 */ 478 #define MAX_SYNCOOKIE_AGE 2 479 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 480 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 481 482 /* syncookies: remember time of last synqueue overflow 483 * But do not dirty this field too often (once per second is enough) 484 * It is racy as we do not hold a lock, but race is very minor. 485 */ 486 static inline void tcp_synq_overflow(const struct sock *sk) 487 { 488 unsigned int last_overflow; 489 unsigned int now = jiffies; 490 491 if (sk->sk_reuseport) { 492 struct sock_reuseport *reuse; 493 494 reuse = rcu_dereference(sk->sk_reuseport_cb); 495 if (likely(reuse)) { 496 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 497 if (!time_between32(now, last_overflow, 498 last_overflow + HZ)) 499 WRITE_ONCE(reuse->synq_overflow_ts, now); 500 return; 501 } 502 } 503 504 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 505 if (!time_between32(now, last_overflow, last_overflow + HZ)) 506 WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now); 507 } 508 509 /* syncookies: no recent synqueue overflow on this listening socket? */ 510 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 511 { 512 unsigned int last_overflow; 513 unsigned int now = jiffies; 514 515 if (sk->sk_reuseport) { 516 struct sock_reuseport *reuse; 517 518 reuse = rcu_dereference(sk->sk_reuseport_cb); 519 if (likely(reuse)) { 520 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 521 return !time_between32(now, last_overflow - HZ, 522 last_overflow + 523 TCP_SYNCOOKIE_VALID); 524 } 525 } 526 527 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 528 529 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 530 * then we're under synflood. However, we have to use 531 * 'last_overflow - HZ' as lower bound. That's because a concurrent 532 * tcp_synq_overflow() could update .ts_recent_stamp after we read 533 * jiffies but before we store .ts_recent_stamp into last_overflow, 534 * which could lead to rejecting a valid syncookie. 535 */ 536 return !time_between32(now, last_overflow - HZ, 537 last_overflow + TCP_SYNCOOKIE_VALID); 538 } 539 540 static inline u32 tcp_cookie_time(void) 541 { 542 u64 val = get_jiffies_64(); 543 544 do_div(val, TCP_SYNCOOKIE_PERIOD); 545 return val; 546 } 547 548 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 549 u16 *mssp); 550 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 551 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 552 bool cookie_timestamp_decode(const struct net *net, 553 struct tcp_options_received *opt); 554 bool cookie_ecn_ok(const struct tcp_options_received *opt, 555 const struct net *net, const struct dst_entry *dst); 556 557 /* From net/ipv6/syncookies.c */ 558 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, 559 u32 cookie); 560 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 561 562 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 563 const struct tcphdr *th, u16 *mssp); 564 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 565 #endif 566 /* tcp_output.c */ 567 568 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 569 int nonagle); 570 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 571 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 572 void tcp_retransmit_timer(struct sock *sk); 573 void tcp_xmit_retransmit_queue(struct sock *); 574 void tcp_simple_retransmit(struct sock *); 575 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 576 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 577 enum tcp_queue { 578 TCP_FRAG_IN_WRITE_QUEUE, 579 TCP_FRAG_IN_RTX_QUEUE, 580 }; 581 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 582 struct sk_buff *skb, u32 len, 583 unsigned int mss_now, gfp_t gfp); 584 585 void tcp_send_probe0(struct sock *); 586 void tcp_send_partial(struct sock *); 587 int tcp_write_wakeup(struct sock *, int mib); 588 void tcp_send_fin(struct sock *sk); 589 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 590 int tcp_send_synack(struct sock *); 591 void tcp_push_one(struct sock *, unsigned int mss_now); 592 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 593 void tcp_send_ack(struct sock *sk); 594 void tcp_send_delayed_ack(struct sock *sk); 595 void tcp_send_loss_probe(struct sock *sk); 596 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 597 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 598 const struct sk_buff *next_skb); 599 600 /* tcp_input.c */ 601 void tcp_rearm_rto(struct sock *sk); 602 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 603 void tcp_reset(struct sock *sk); 604 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb); 605 void tcp_fin(struct sock *sk); 606 607 /* tcp_timer.c */ 608 void tcp_init_xmit_timers(struct sock *); 609 static inline void tcp_clear_xmit_timers(struct sock *sk) 610 { 611 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 612 __sock_put(sk); 613 614 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 615 __sock_put(sk); 616 617 inet_csk_clear_xmit_timers(sk); 618 } 619 620 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 621 unsigned int tcp_current_mss(struct sock *sk); 622 623 /* Bound MSS / TSO packet size with the half of the window */ 624 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 625 { 626 int cutoff; 627 628 /* When peer uses tiny windows, there is no use in packetizing 629 * to sub-MSS pieces for the sake of SWS or making sure there 630 * are enough packets in the pipe for fast recovery. 631 * 632 * On the other hand, for extremely large MSS devices, handling 633 * smaller than MSS windows in this way does make sense. 634 */ 635 if (tp->max_window > TCP_MSS_DEFAULT) 636 cutoff = (tp->max_window >> 1); 637 else 638 cutoff = tp->max_window; 639 640 if (cutoff && pktsize > cutoff) 641 return max_t(int, cutoff, 68U - tp->tcp_header_len); 642 else 643 return pktsize; 644 } 645 646 /* tcp.c */ 647 void tcp_get_info(struct sock *, struct tcp_info *); 648 649 /* Read 'sendfile()'-style from a TCP socket */ 650 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 651 sk_read_actor_t recv_actor); 652 653 void tcp_initialize_rcv_mss(struct sock *sk); 654 655 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 656 int tcp_mss_to_mtu(struct sock *sk, int mss); 657 void tcp_mtup_init(struct sock *sk); 658 void tcp_init_buffer_space(struct sock *sk); 659 660 static inline void tcp_bound_rto(const struct sock *sk) 661 { 662 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 663 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 664 } 665 666 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 667 { 668 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 669 } 670 671 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 672 { 673 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 674 ntohl(TCP_FLAG_ACK) | 675 snd_wnd); 676 } 677 678 static inline void tcp_fast_path_on(struct tcp_sock *tp) 679 { 680 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 681 } 682 683 static inline void tcp_fast_path_check(struct sock *sk) 684 { 685 struct tcp_sock *tp = tcp_sk(sk); 686 687 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 688 tp->rcv_wnd && 689 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 690 !tp->urg_data) 691 tcp_fast_path_on(tp); 692 } 693 694 /* Compute the actual rto_min value */ 695 static inline u32 tcp_rto_min(struct sock *sk) 696 { 697 const struct dst_entry *dst = __sk_dst_get(sk); 698 u32 rto_min = TCP_RTO_MIN; 699 700 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 701 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 702 return rto_min; 703 } 704 705 static inline u32 tcp_rto_min_us(struct sock *sk) 706 { 707 return jiffies_to_usecs(tcp_rto_min(sk)); 708 } 709 710 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 711 { 712 return dst_metric_locked(dst, RTAX_CC_ALGO); 713 } 714 715 /* Minimum RTT in usec. ~0 means not available. */ 716 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 717 { 718 return minmax_get(&tp->rtt_min); 719 } 720 721 /* Compute the actual receive window we are currently advertising. 722 * Rcv_nxt can be after the window if our peer push more data 723 * than the offered window. 724 */ 725 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 726 { 727 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 728 729 if (win < 0) 730 win = 0; 731 return (u32) win; 732 } 733 734 /* Choose a new window, without checks for shrinking, and without 735 * scaling applied to the result. The caller does these things 736 * if necessary. This is a "raw" window selection. 737 */ 738 u32 __tcp_select_window(struct sock *sk); 739 740 void tcp_send_window_probe(struct sock *sk); 741 742 /* TCP uses 32bit jiffies to save some space. 743 * Note that this is different from tcp_time_stamp, which 744 * historically has been the same until linux-4.13. 745 */ 746 #define tcp_jiffies32 ((u32)jiffies) 747 748 /* 749 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 750 * It is no longer tied to jiffies, but to 1 ms clock. 751 * Note: double check if you want to use tcp_jiffies32 instead of this. 752 */ 753 #define TCP_TS_HZ 1000 754 755 static inline u64 tcp_clock_ns(void) 756 { 757 return ktime_get_ns(); 758 } 759 760 static inline u64 tcp_clock_us(void) 761 { 762 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 763 } 764 765 /* This should only be used in contexts where tp->tcp_mstamp is up to date */ 766 static inline u32 tcp_time_stamp(const struct tcp_sock *tp) 767 { 768 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); 769 } 770 771 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ 772 static inline u32 tcp_ns_to_ts(u64 ns) 773 { 774 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); 775 } 776 777 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ 778 static inline u32 tcp_time_stamp_raw(void) 779 { 780 return tcp_ns_to_ts(tcp_clock_ns()); 781 } 782 783 void tcp_mstamp_refresh(struct tcp_sock *tp); 784 785 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 786 { 787 return max_t(s64, t1 - t0, 0); 788 } 789 790 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 791 { 792 return tcp_ns_to_ts(skb->skb_mstamp_ns); 793 } 794 795 /* provide the departure time in us unit */ 796 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 797 { 798 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 799 } 800 801 802 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 803 804 #define TCPHDR_FIN 0x01 805 #define TCPHDR_SYN 0x02 806 #define TCPHDR_RST 0x04 807 #define TCPHDR_PSH 0x08 808 #define TCPHDR_ACK 0x10 809 #define TCPHDR_URG 0x20 810 #define TCPHDR_ECE 0x40 811 #define TCPHDR_CWR 0x80 812 813 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 814 815 /* This is what the send packet queuing engine uses to pass 816 * TCP per-packet control information to the transmission code. 817 * We also store the host-order sequence numbers in here too. 818 * This is 44 bytes if IPV6 is enabled. 819 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 820 */ 821 struct tcp_skb_cb { 822 __u32 seq; /* Starting sequence number */ 823 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 824 union { 825 /* Note : tcp_tw_isn is used in input path only 826 * (isn chosen by tcp_timewait_state_process()) 827 * 828 * tcp_gso_segs/size are used in write queue only, 829 * cf tcp_skb_pcount()/tcp_skb_mss() 830 */ 831 __u32 tcp_tw_isn; 832 struct { 833 u16 tcp_gso_segs; 834 u16 tcp_gso_size; 835 }; 836 }; 837 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 838 839 __u8 sacked; /* State flags for SACK. */ 840 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 841 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 842 #define TCPCB_LOST 0x04 /* SKB is lost */ 843 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 844 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 845 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 846 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 847 TCPCB_REPAIRED) 848 849 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 850 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 851 eor:1, /* Is skb MSG_EOR marked? */ 852 has_rxtstamp:1, /* SKB has a RX timestamp */ 853 unused:5; 854 __u32 ack_seq; /* Sequence number ACK'd */ 855 union { 856 struct { 857 /* There is space for up to 24 bytes */ 858 __u32 in_flight:30,/* Bytes in flight at transmit */ 859 is_app_limited:1, /* cwnd not fully used? */ 860 unused:1; 861 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 862 __u32 delivered; 863 /* start of send pipeline phase */ 864 u64 first_tx_mstamp; 865 /* when we reached the "delivered" count */ 866 u64 delivered_mstamp; 867 } tx; /* only used for outgoing skbs */ 868 union { 869 struct inet_skb_parm h4; 870 #if IS_ENABLED(CONFIG_IPV6) 871 struct inet6_skb_parm h6; 872 #endif 873 } header; /* For incoming skbs */ 874 struct { 875 __u32 flags; 876 struct sock *sk_redir; 877 void *data_end; 878 } bpf; 879 }; 880 }; 881 882 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 883 884 static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb) 885 { 886 TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb); 887 } 888 889 static inline bool tcp_skb_bpf_ingress(const struct sk_buff *skb) 890 { 891 return TCP_SKB_CB(skb)->bpf.flags & BPF_F_INGRESS; 892 } 893 894 static inline struct sock *tcp_skb_bpf_redirect_fetch(struct sk_buff *skb) 895 { 896 return TCP_SKB_CB(skb)->bpf.sk_redir; 897 } 898 899 static inline void tcp_skb_bpf_redirect_clear(struct sk_buff *skb) 900 { 901 TCP_SKB_CB(skb)->bpf.sk_redir = NULL; 902 } 903 904 #if IS_ENABLED(CONFIG_IPV6) 905 /* This is the variant of inet6_iif() that must be used by TCP, 906 * as TCP moves IP6CB into a different location in skb->cb[] 907 */ 908 static inline int tcp_v6_iif(const struct sk_buff *skb) 909 { 910 return TCP_SKB_CB(skb)->header.h6.iif; 911 } 912 913 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 914 { 915 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 916 917 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 918 } 919 920 /* TCP_SKB_CB reference means this can not be used from early demux */ 921 static inline int tcp_v6_sdif(const struct sk_buff *skb) 922 { 923 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 924 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 925 return TCP_SKB_CB(skb)->header.h6.iif; 926 #endif 927 return 0; 928 } 929 #endif 930 931 static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb) 932 { 933 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 934 if (!net->ipv4.sysctl_tcp_l3mdev_accept && 935 skb && ipv4_l3mdev_skb(IPCB(skb)->flags)) 936 return true; 937 #endif 938 return false; 939 } 940 941 /* TCP_SKB_CB reference means this can not be used from early demux */ 942 static inline int tcp_v4_sdif(struct sk_buff *skb) 943 { 944 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 945 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 946 return TCP_SKB_CB(skb)->header.h4.iif; 947 #endif 948 return 0; 949 } 950 951 /* Due to TSO, an SKB can be composed of multiple actual 952 * packets. To keep these tracked properly, we use this. 953 */ 954 static inline int tcp_skb_pcount(const struct sk_buff *skb) 955 { 956 return TCP_SKB_CB(skb)->tcp_gso_segs; 957 } 958 959 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 960 { 961 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 962 } 963 964 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 965 { 966 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 967 } 968 969 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 970 static inline int tcp_skb_mss(const struct sk_buff *skb) 971 { 972 return TCP_SKB_CB(skb)->tcp_gso_size; 973 } 974 975 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 976 { 977 return likely(!TCP_SKB_CB(skb)->eor); 978 } 979 980 /* Events passed to congestion control interface */ 981 enum tcp_ca_event { 982 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 983 CA_EVENT_CWND_RESTART, /* congestion window restart */ 984 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 985 CA_EVENT_LOSS, /* loss timeout */ 986 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 987 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 988 }; 989 990 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 991 enum tcp_ca_ack_event_flags { 992 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 993 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 994 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 995 }; 996 997 /* 998 * Interface for adding new TCP congestion control handlers 999 */ 1000 #define TCP_CA_NAME_MAX 16 1001 #define TCP_CA_MAX 128 1002 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1003 1004 #define TCP_CA_UNSPEC 0 1005 1006 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1007 #define TCP_CONG_NON_RESTRICTED 0x1 1008 /* Requires ECN/ECT set on all packets */ 1009 #define TCP_CONG_NEEDS_ECN 0x2 1010 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1011 1012 union tcp_cc_info; 1013 1014 struct ack_sample { 1015 u32 pkts_acked; 1016 s32 rtt_us; 1017 u32 in_flight; 1018 }; 1019 1020 /* A rate sample measures the number of (original/retransmitted) data 1021 * packets delivered "delivered" over an interval of time "interval_us". 1022 * The tcp_rate.c code fills in the rate sample, and congestion 1023 * control modules that define a cong_control function to run at the end 1024 * of ACK processing can optionally chose to consult this sample when 1025 * setting cwnd and pacing rate. 1026 * A sample is invalid if "delivered" or "interval_us" is negative. 1027 */ 1028 struct rate_sample { 1029 u64 prior_mstamp; /* starting timestamp for interval */ 1030 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1031 s32 delivered; /* number of packets delivered over interval */ 1032 long interval_us; /* time for tp->delivered to incr "delivered" */ 1033 u32 snd_interval_us; /* snd interval for delivered packets */ 1034 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1035 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1036 int losses; /* number of packets marked lost upon ACK */ 1037 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1038 u32 prior_in_flight; /* in flight before this ACK */ 1039 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1040 bool is_retrans; /* is sample from retransmission? */ 1041 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1042 }; 1043 1044 struct tcp_congestion_ops { 1045 struct list_head list; 1046 u32 key; 1047 u32 flags; 1048 1049 /* initialize private data (optional) */ 1050 void (*init)(struct sock *sk); 1051 /* cleanup private data (optional) */ 1052 void (*release)(struct sock *sk); 1053 1054 /* return slow start threshold (required) */ 1055 u32 (*ssthresh)(struct sock *sk); 1056 /* do new cwnd calculation (required) */ 1057 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1058 /* call before changing ca_state (optional) */ 1059 void (*set_state)(struct sock *sk, u8 new_state); 1060 /* call when cwnd event occurs (optional) */ 1061 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1062 /* call when ack arrives (optional) */ 1063 void (*in_ack_event)(struct sock *sk, u32 flags); 1064 /* new value of cwnd after loss (required) */ 1065 u32 (*undo_cwnd)(struct sock *sk); 1066 /* hook for packet ack accounting (optional) */ 1067 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1068 /* override sysctl_tcp_min_tso_segs */ 1069 u32 (*min_tso_segs)(struct sock *sk); 1070 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1071 u32 (*sndbuf_expand)(struct sock *sk); 1072 /* call when packets are delivered to update cwnd and pacing rate, 1073 * after all the ca_state processing. (optional) 1074 */ 1075 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1076 /* get info for inet_diag (optional) */ 1077 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1078 union tcp_cc_info *info); 1079 1080 char name[TCP_CA_NAME_MAX]; 1081 struct module *owner; 1082 }; 1083 1084 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1085 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1086 1087 void tcp_assign_congestion_control(struct sock *sk); 1088 void tcp_init_congestion_control(struct sock *sk); 1089 void tcp_cleanup_congestion_control(struct sock *sk); 1090 int tcp_set_default_congestion_control(struct net *net, const char *name); 1091 void tcp_get_default_congestion_control(struct net *net, char *name); 1092 void tcp_get_available_congestion_control(char *buf, size_t len); 1093 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1094 int tcp_set_allowed_congestion_control(char *allowed); 1095 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1096 bool reinit, bool cap_net_admin); 1097 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1098 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1099 1100 u32 tcp_reno_ssthresh(struct sock *sk); 1101 u32 tcp_reno_undo_cwnd(struct sock *sk); 1102 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1103 extern struct tcp_congestion_ops tcp_reno; 1104 1105 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1106 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1107 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1108 #ifdef CONFIG_INET 1109 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1110 #else 1111 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1112 { 1113 return NULL; 1114 } 1115 #endif 1116 1117 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1118 { 1119 const struct inet_connection_sock *icsk = inet_csk(sk); 1120 1121 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1122 } 1123 1124 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 1125 { 1126 struct inet_connection_sock *icsk = inet_csk(sk); 1127 1128 if (icsk->icsk_ca_ops->set_state) 1129 icsk->icsk_ca_ops->set_state(sk, ca_state); 1130 icsk->icsk_ca_state = ca_state; 1131 } 1132 1133 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1134 { 1135 const struct inet_connection_sock *icsk = inet_csk(sk); 1136 1137 if (icsk->icsk_ca_ops->cwnd_event) 1138 icsk->icsk_ca_ops->cwnd_event(sk, event); 1139 } 1140 1141 /* From tcp_rate.c */ 1142 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1143 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1144 struct rate_sample *rs); 1145 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1146 bool is_sack_reneg, struct rate_sample *rs); 1147 void tcp_rate_check_app_limited(struct sock *sk); 1148 1149 /* These functions determine how the current flow behaves in respect of SACK 1150 * handling. SACK is negotiated with the peer, and therefore it can vary 1151 * between different flows. 1152 * 1153 * tcp_is_sack - SACK enabled 1154 * tcp_is_reno - No SACK 1155 */ 1156 static inline int tcp_is_sack(const struct tcp_sock *tp) 1157 { 1158 return likely(tp->rx_opt.sack_ok); 1159 } 1160 1161 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1162 { 1163 return !tcp_is_sack(tp); 1164 } 1165 1166 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1167 { 1168 return tp->sacked_out + tp->lost_out; 1169 } 1170 1171 /* This determines how many packets are "in the network" to the best 1172 * of our knowledge. In many cases it is conservative, but where 1173 * detailed information is available from the receiver (via SACK 1174 * blocks etc.) we can make more aggressive calculations. 1175 * 1176 * Use this for decisions involving congestion control, use just 1177 * tp->packets_out to determine if the send queue is empty or not. 1178 * 1179 * Read this equation as: 1180 * 1181 * "Packets sent once on transmission queue" MINUS 1182 * "Packets left network, but not honestly ACKed yet" PLUS 1183 * "Packets fast retransmitted" 1184 */ 1185 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1186 { 1187 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1188 } 1189 1190 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1191 1192 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1193 { 1194 return tp->snd_cwnd < tp->snd_ssthresh; 1195 } 1196 1197 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1198 { 1199 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1200 } 1201 1202 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1203 { 1204 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1205 (1 << inet_csk(sk)->icsk_ca_state); 1206 } 1207 1208 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1209 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1210 * ssthresh. 1211 */ 1212 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1213 { 1214 const struct tcp_sock *tp = tcp_sk(sk); 1215 1216 if (tcp_in_cwnd_reduction(sk)) 1217 return tp->snd_ssthresh; 1218 else 1219 return max(tp->snd_ssthresh, 1220 ((tp->snd_cwnd >> 1) + 1221 (tp->snd_cwnd >> 2))); 1222 } 1223 1224 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1225 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1226 1227 void tcp_enter_cwr(struct sock *sk); 1228 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1229 1230 /* The maximum number of MSS of available cwnd for which TSO defers 1231 * sending if not using sysctl_tcp_tso_win_divisor. 1232 */ 1233 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1234 { 1235 return 3; 1236 } 1237 1238 /* Returns end sequence number of the receiver's advertised window */ 1239 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1240 { 1241 return tp->snd_una + tp->snd_wnd; 1242 } 1243 1244 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1245 * flexible approach. The RFC suggests cwnd should not be raised unless 1246 * it was fully used previously. And that's exactly what we do in 1247 * congestion avoidance mode. But in slow start we allow cwnd to grow 1248 * as long as the application has used half the cwnd. 1249 * Example : 1250 * cwnd is 10 (IW10), but application sends 9 frames. 1251 * We allow cwnd to reach 18 when all frames are ACKed. 1252 * This check is safe because it's as aggressive as slow start which already 1253 * risks 100% overshoot. The advantage is that we discourage application to 1254 * either send more filler packets or data to artificially blow up the cwnd 1255 * usage, and allow application-limited process to probe bw more aggressively. 1256 */ 1257 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1258 { 1259 const struct tcp_sock *tp = tcp_sk(sk); 1260 1261 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1262 if (tcp_in_slow_start(tp)) 1263 return tp->snd_cwnd < 2 * tp->max_packets_out; 1264 1265 return tp->is_cwnd_limited; 1266 } 1267 1268 /* BBR congestion control needs pacing. 1269 * Same remark for SO_MAX_PACING_RATE. 1270 * sch_fq packet scheduler is efficiently handling pacing, 1271 * but is not always installed/used. 1272 * Return true if TCP stack should pace packets itself. 1273 */ 1274 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1275 { 1276 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1277 } 1278 1279 /* Return in jiffies the delay before one skb is sent. 1280 * If @skb is NULL, we look at EDT for next packet being sent on the socket. 1281 */ 1282 static inline unsigned long tcp_pacing_delay(const struct sock *sk, 1283 const struct sk_buff *skb) 1284 { 1285 s64 pacing_delay = skb ? skb->tstamp : tcp_sk(sk)->tcp_wstamp_ns; 1286 1287 pacing_delay -= tcp_sk(sk)->tcp_clock_cache; 1288 1289 return pacing_delay > 0 ? nsecs_to_jiffies(pacing_delay) : 0; 1290 } 1291 1292 static inline void tcp_reset_xmit_timer(struct sock *sk, 1293 const int what, 1294 unsigned long when, 1295 const unsigned long max_when, 1296 const struct sk_buff *skb) 1297 { 1298 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk, skb), 1299 max_when); 1300 } 1301 1302 /* Something is really bad, we could not queue an additional packet, 1303 * because qdisc is full or receiver sent a 0 window, or we are paced. 1304 * We do not want to add fuel to the fire, or abort too early, 1305 * so make sure the timer we arm now is at least 200ms in the future, 1306 * regardless of current icsk_rto value (as it could be ~2ms) 1307 */ 1308 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1309 { 1310 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1311 } 1312 1313 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1314 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1315 unsigned long max_when) 1316 { 1317 u64 when = (u64)tcp_probe0_base(sk) << inet_csk(sk)->icsk_backoff; 1318 1319 return (unsigned long)min_t(u64, when, max_when); 1320 } 1321 1322 static inline void tcp_check_probe_timer(struct sock *sk) 1323 { 1324 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1325 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1326 tcp_probe0_base(sk), TCP_RTO_MAX, 1327 NULL); 1328 } 1329 1330 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1331 { 1332 tp->snd_wl1 = seq; 1333 } 1334 1335 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1336 { 1337 tp->snd_wl1 = seq; 1338 } 1339 1340 /* 1341 * Calculate(/check) TCP checksum 1342 */ 1343 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1344 __be32 daddr, __wsum base) 1345 { 1346 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1347 } 1348 1349 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1350 { 1351 return !skb_csum_unnecessary(skb) && 1352 __skb_checksum_complete(skb); 1353 } 1354 1355 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); 1356 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1357 void tcp_set_state(struct sock *sk, int state); 1358 void tcp_done(struct sock *sk); 1359 int tcp_abort(struct sock *sk, int err); 1360 1361 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1362 { 1363 rx_opt->dsack = 0; 1364 rx_opt->num_sacks = 0; 1365 } 1366 1367 u32 tcp_default_init_rwnd(u32 mss); 1368 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1369 1370 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1371 { 1372 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1373 struct tcp_sock *tp = tcp_sk(sk); 1374 s32 delta; 1375 1376 if (!sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle || tp->packets_out || 1377 ca_ops->cong_control) 1378 return; 1379 delta = tcp_jiffies32 - tp->lsndtime; 1380 if (delta > inet_csk(sk)->icsk_rto) 1381 tcp_cwnd_restart(sk, delta); 1382 } 1383 1384 /* Determine a window scaling and initial window to offer. */ 1385 void tcp_select_initial_window(const struct sock *sk, int __space, 1386 __u32 mss, __u32 *rcv_wnd, 1387 __u32 *window_clamp, int wscale_ok, 1388 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1389 1390 static inline int tcp_win_from_space(const struct sock *sk, int space) 1391 { 1392 int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; 1393 1394 return tcp_adv_win_scale <= 0 ? 1395 (space>>(-tcp_adv_win_scale)) : 1396 space - (space>>tcp_adv_win_scale); 1397 } 1398 1399 /* Note: caller must be prepared to deal with negative returns */ 1400 static inline int tcp_space(const struct sock *sk) 1401 { 1402 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1403 READ_ONCE(sk->sk_backlog.len) - 1404 atomic_read(&sk->sk_rmem_alloc)); 1405 } 1406 1407 static inline int tcp_full_space(const struct sock *sk) 1408 { 1409 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1410 } 1411 1412 extern void tcp_openreq_init_rwin(struct request_sock *req, 1413 const struct sock *sk_listener, 1414 const struct dst_entry *dst); 1415 1416 void tcp_enter_memory_pressure(struct sock *sk); 1417 void tcp_leave_memory_pressure(struct sock *sk); 1418 1419 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1420 { 1421 struct net *net = sock_net((struct sock *)tp); 1422 1423 return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl; 1424 } 1425 1426 static inline int keepalive_time_when(const struct tcp_sock *tp) 1427 { 1428 struct net *net = sock_net((struct sock *)tp); 1429 1430 return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time; 1431 } 1432 1433 static inline int keepalive_probes(const struct tcp_sock *tp) 1434 { 1435 struct net *net = sock_net((struct sock *)tp); 1436 1437 return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes; 1438 } 1439 1440 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1441 { 1442 const struct inet_connection_sock *icsk = &tp->inet_conn; 1443 1444 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1445 tcp_jiffies32 - tp->rcv_tstamp); 1446 } 1447 1448 static inline int tcp_fin_time(const struct sock *sk) 1449 { 1450 int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout; 1451 const int rto = inet_csk(sk)->icsk_rto; 1452 1453 if (fin_timeout < (rto << 2) - (rto >> 1)) 1454 fin_timeout = (rto << 2) - (rto >> 1); 1455 1456 return fin_timeout; 1457 } 1458 1459 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1460 int paws_win) 1461 { 1462 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1463 return true; 1464 if (unlikely(!time_before32(ktime_get_seconds(), 1465 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1466 return true; 1467 /* 1468 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1469 * then following tcp messages have valid values. Ignore 0 value, 1470 * or else 'negative' tsval might forbid us to accept their packets. 1471 */ 1472 if (!rx_opt->ts_recent) 1473 return true; 1474 return false; 1475 } 1476 1477 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1478 int rst) 1479 { 1480 if (tcp_paws_check(rx_opt, 0)) 1481 return false; 1482 1483 /* RST segments are not recommended to carry timestamp, 1484 and, if they do, it is recommended to ignore PAWS because 1485 "their cleanup function should take precedence over timestamps." 1486 Certainly, it is mistake. It is necessary to understand the reasons 1487 of this constraint to relax it: if peer reboots, clock may go 1488 out-of-sync and half-open connections will not be reset. 1489 Actually, the problem would be not existing if all 1490 the implementations followed draft about maintaining clock 1491 via reboots. Linux-2.2 DOES NOT! 1492 1493 However, we can relax time bounds for RST segments to MSL. 1494 */ 1495 if (rst && !time_before32(ktime_get_seconds(), 1496 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1497 return false; 1498 return true; 1499 } 1500 1501 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1502 int mib_idx, u32 *last_oow_ack_time); 1503 1504 static inline void tcp_mib_init(struct net *net) 1505 { 1506 /* See RFC 2012 */ 1507 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1508 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1509 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1510 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1511 } 1512 1513 /* from STCP */ 1514 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1515 { 1516 tp->lost_skb_hint = NULL; 1517 } 1518 1519 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1520 { 1521 tcp_clear_retrans_hints_partial(tp); 1522 tp->retransmit_skb_hint = NULL; 1523 } 1524 1525 union tcp_md5_addr { 1526 struct in_addr a4; 1527 #if IS_ENABLED(CONFIG_IPV6) 1528 struct in6_addr a6; 1529 #endif 1530 }; 1531 1532 /* - key database */ 1533 struct tcp_md5sig_key { 1534 struct hlist_node node; 1535 u8 keylen; 1536 u8 family; /* AF_INET or AF_INET6 */ 1537 u8 prefixlen; 1538 union tcp_md5_addr addr; 1539 int l3index; /* set if key added with L3 scope */ 1540 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1541 struct rcu_head rcu; 1542 }; 1543 1544 /* - sock block */ 1545 struct tcp_md5sig_info { 1546 struct hlist_head head; 1547 struct rcu_head rcu; 1548 }; 1549 1550 /* - pseudo header */ 1551 struct tcp4_pseudohdr { 1552 __be32 saddr; 1553 __be32 daddr; 1554 __u8 pad; 1555 __u8 protocol; 1556 __be16 len; 1557 }; 1558 1559 struct tcp6_pseudohdr { 1560 struct in6_addr saddr; 1561 struct in6_addr daddr; 1562 __be32 len; 1563 __be32 protocol; /* including padding */ 1564 }; 1565 1566 union tcp_md5sum_block { 1567 struct tcp4_pseudohdr ip4; 1568 #if IS_ENABLED(CONFIG_IPV6) 1569 struct tcp6_pseudohdr ip6; 1570 #endif 1571 }; 1572 1573 /* - pool: digest algorithm, hash description and scratch buffer */ 1574 struct tcp_md5sig_pool { 1575 struct ahash_request *md5_req; 1576 void *scratch; 1577 }; 1578 1579 /* - functions */ 1580 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1581 const struct sock *sk, const struct sk_buff *skb); 1582 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1583 int family, u8 prefixlen, int l3index, 1584 const u8 *newkey, u8 newkeylen, gfp_t gfp); 1585 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1586 int family, u8 prefixlen, int l3index); 1587 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1588 const struct sock *addr_sk); 1589 1590 #ifdef CONFIG_TCP_MD5SIG 1591 #include <linux/jump_label.h> 1592 extern struct static_key_false tcp_md5_needed; 1593 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1594 const union tcp_md5_addr *addr, 1595 int family); 1596 static inline struct tcp_md5sig_key * 1597 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1598 const union tcp_md5_addr *addr, int family) 1599 { 1600 if (!static_branch_unlikely(&tcp_md5_needed)) 1601 return NULL; 1602 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1603 } 1604 1605 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1606 #else 1607 static inline struct tcp_md5sig_key * 1608 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1609 const union tcp_md5_addr *addr, int family) 1610 { 1611 return NULL; 1612 } 1613 #define tcp_twsk_md5_key(twsk) NULL 1614 #endif 1615 1616 bool tcp_alloc_md5sig_pool(void); 1617 1618 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1619 static inline void tcp_put_md5sig_pool(void) 1620 { 1621 local_bh_enable(); 1622 } 1623 1624 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1625 unsigned int header_len); 1626 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1627 const struct tcp_md5sig_key *key); 1628 1629 /* From tcp_fastopen.c */ 1630 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1631 struct tcp_fastopen_cookie *cookie); 1632 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1633 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1634 u16 try_exp); 1635 struct tcp_fastopen_request { 1636 /* Fast Open cookie. Size 0 means a cookie request */ 1637 struct tcp_fastopen_cookie cookie; 1638 struct msghdr *data; /* data in MSG_FASTOPEN */ 1639 size_t size; 1640 int copied; /* queued in tcp_connect() */ 1641 struct ubuf_info *uarg; 1642 }; 1643 void tcp_free_fastopen_req(struct tcp_sock *tp); 1644 void tcp_fastopen_destroy_cipher(struct sock *sk); 1645 void tcp_fastopen_ctx_destroy(struct net *net); 1646 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1647 void *primary_key, void *backup_key); 1648 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1649 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1650 struct request_sock *req, 1651 struct tcp_fastopen_cookie *foc, 1652 const struct dst_entry *dst); 1653 void tcp_fastopen_init_key_once(struct net *net); 1654 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1655 struct tcp_fastopen_cookie *cookie); 1656 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1657 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1658 #define TCP_FASTOPEN_KEY_MAX 2 1659 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1660 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1661 1662 /* Fastopen key context */ 1663 struct tcp_fastopen_context { 1664 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1665 int num; 1666 struct rcu_head rcu; 1667 }; 1668 1669 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout; 1670 void tcp_fastopen_active_disable(struct sock *sk); 1671 bool tcp_fastopen_active_should_disable(struct sock *sk); 1672 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1673 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1674 1675 /* Caller needs to wrap with rcu_read_(un)lock() */ 1676 static inline 1677 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1678 { 1679 struct tcp_fastopen_context *ctx; 1680 1681 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1682 if (!ctx) 1683 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1684 return ctx; 1685 } 1686 1687 static inline 1688 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1689 const struct tcp_fastopen_cookie *orig) 1690 { 1691 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1692 orig->len == foc->len && 1693 !memcmp(orig->val, foc->val, foc->len)) 1694 return true; 1695 return false; 1696 } 1697 1698 static inline 1699 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1700 { 1701 return ctx->num; 1702 } 1703 1704 /* Latencies incurred by various limits for a sender. They are 1705 * chronograph-like stats that are mutually exclusive. 1706 */ 1707 enum tcp_chrono { 1708 TCP_CHRONO_UNSPEC, 1709 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1710 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1711 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1712 __TCP_CHRONO_MAX, 1713 }; 1714 1715 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1716 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1717 1718 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1719 * the same memory storage than skb->destructor/_skb_refdst 1720 */ 1721 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1722 { 1723 skb->destructor = NULL; 1724 skb->_skb_refdst = 0UL; 1725 } 1726 1727 #define tcp_skb_tsorted_save(skb) { \ 1728 unsigned long _save = skb->_skb_refdst; \ 1729 skb->_skb_refdst = 0UL; 1730 1731 #define tcp_skb_tsorted_restore(skb) \ 1732 skb->_skb_refdst = _save; \ 1733 } 1734 1735 void tcp_write_queue_purge(struct sock *sk); 1736 1737 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1738 { 1739 return skb_rb_first(&sk->tcp_rtx_queue); 1740 } 1741 1742 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1743 { 1744 return skb_rb_last(&sk->tcp_rtx_queue); 1745 } 1746 1747 static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) 1748 { 1749 return skb_peek(&sk->sk_write_queue); 1750 } 1751 1752 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1753 { 1754 return skb_peek_tail(&sk->sk_write_queue); 1755 } 1756 1757 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1758 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1759 1760 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1761 { 1762 return skb_peek(&sk->sk_write_queue); 1763 } 1764 1765 static inline bool tcp_skb_is_last(const struct sock *sk, 1766 const struct sk_buff *skb) 1767 { 1768 return skb_queue_is_last(&sk->sk_write_queue, skb); 1769 } 1770 1771 /** 1772 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1773 * @sk: socket 1774 * 1775 * Since the write queue can have a temporary empty skb in it, 1776 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1777 */ 1778 static inline bool tcp_write_queue_empty(const struct sock *sk) 1779 { 1780 const struct tcp_sock *tp = tcp_sk(sk); 1781 1782 return tp->write_seq == tp->snd_nxt; 1783 } 1784 1785 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1786 { 1787 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1788 } 1789 1790 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1791 { 1792 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1793 } 1794 1795 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1796 { 1797 __skb_queue_tail(&sk->sk_write_queue, skb); 1798 1799 /* Queue it, remembering where we must start sending. */ 1800 if (sk->sk_write_queue.next == skb) 1801 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1802 } 1803 1804 /* Insert new before skb on the write queue of sk. */ 1805 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1806 struct sk_buff *skb, 1807 struct sock *sk) 1808 { 1809 __skb_queue_before(&sk->sk_write_queue, skb, new); 1810 } 1811 1812 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1813 { 1814 tcp_skb_tsorted_anchor_cleanup(skb); 1815 __skb_unlink(skb, &sk->sk_write_queue); 1816 } 1817 1818 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1819 1820 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1821 { 1822 tcp_skb_tsorted_anchor_cleanup(skb); 1823 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1824 } 1825 1826 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1827 { 1828 list_del(&skb->tcp_tsorted_anchor); 1829 tcp_rtx_queue_unlink(skb, sk); 1830 sk_wmem_free_skb(sk, skb); 1831 } 1832 1833 static inline void tcp_push_pending_frames(struct sock *sk) 1834 { 1835 if (tcp_send_head(sk)) { 1836 struct tcp_sock *tp = tcp_sk(sk); 1837 1838 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1839 } 1840 } 1841 1842 /* Start sequence of the skb just after the highest skb with SACKed 1843 * bit, valid only if sacked_out > 0 or when the caller has ensured 1844 * validity by itself. 1845 */ 1846 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1847 { 1848 if (!tp->sacked_out) 1849 return tp->snd_una; 1850 1851 if (tp->highest_sack == NULL) 1852 return tp->snd_nxt; 1853 1854 return TCP_SKB_CB(tp->highest_sack)->seq; 1855 } 1856 1857 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1858 { 1859 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 1860 } 1861 1862 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1863 { 1864 return tcp_sk(sk)->highest_sack; 1865 } 1866 1867 static inline void tcp_highest_sack_reset(struct sock *sk) 1868 { 1869 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 1870 } 1871 1872 /* Called when old skb is about to be deleted and replaced by new skb */ 1873 static inline void tcp_highest_sack_replace(struct sock *sk, 1874 struct sk_buff *old, 1875 struct sk_buff *new) 1876 { 1877 if (old == tcp_highest_sack(sk)) 1878 tcp_sk(sk)->highest_sack = new; 1879 } 1880 1881 /* This helper checks if socket has IP_TRANSPARENT set */ 1882 static inline bool inet_sk_transparent(const struct sock *sk) 1883 { 1884 switch (sk->sk_state) { 1885 case TCP_TIME_WAIT: 1886 return inet_twsk(sk)->tw_transparent; 1887 case TCP_NEW_SYN_RECV: 1888 return inet_rsk(inet_reqsk(sk))->no_srccheck; 1889 } 1890 return inet_sk(sk)->transparent; 1891 } 1892 1893 /* Determines whether this is a thin stream (which may suffer from 1894 * increased latency). Used to trigger latency-reducing mechanisms. 1895 */ 1896 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 1897 { 1898 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 1899 } 1900 1901 /* /proc */ 1902 enum tcp_seq_states { 1903 TCP_SEQ_STATE_LISTENING, 1904 TCP_SEQ_STATE_ESTABLISHED, 1905 }; 1906 1907 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 1908 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 1909 void tcp_seq_stop(struct seq_file *seq, void *v); 1910 1911 struct tcp_seq_afinfo { 1912 sa_family_t family; 1913 }; 1914 1915 struct tcp_iter_state { 1916 struct seq_net_private p; 1917 enum tcp_seq_states state; 1918 struct sock *syn_wait_sk; 1919 int bucket, offset, sbucket, num; 1920 loff_t last_pos; 1921 }; 1922 1923 extern struct request_sock_ops tcp_request_sock_ops; 1924 extern struct request_sock_ops tcp6_request_sock_ops; 1925 1926 void tcp_v4_destroy_sock(struct sock *sk); 1927 1928 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 1929 netdev_features_t features); 1930 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 1931 int tcp_gro_complete(struct sk_buff *skb); 1932 1933 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 1934 1935 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 1936 { 1937 struct net *net = sock_net((struct sock *)tp); 1938 return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat; 1939 } 1940 1941 /* @wake is one when sk_stream_write_space() calls us. 1942 * This sends EPOLLOUT only if notsent_bytes is half the limit. 1943 * This mimics the strategy used in sock_def_write_space(). 1944 */ 1945 static inline bool tcp_stream_memory_free(const struct sock *sk, int wake) 1946 { 1947 const struct tcp_sock *tp = tcp_sk(sk); 1948 u32 notsent_bytes = READ_ONCE(tp->write_seq) - 1949 READ_ONCE(tp->snd_nxt); 1950 1951 return (notsent_bytes << wake) < tcp_notsent_lowat(tp); 1952 } 1953 1954 #ifdef CONFIG_PROC_FS 1955 int tcp4_proc_init(void); 1956 void tcp4_proc_exit(void); 1957 #endif 1958 1959 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 1960 int tcp_conn_request(struct request_sock_ops *rsk_ops, 1961 const struct tcp_request_sock_ops *af_ops, 1962 struct sock *sk, struct sk_buff *skb); 1963 1964 /* TCP af-specific functions */ 1965 struct tcp_sock_af_ops { 1966 #ifdef CONFIG_TCP_MD5SIG 1967 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 1968 const struct sock *addr_sk); 1969 int (*calc_md5_hash)(char *location, 1970 const struct tcp_md5sig_key *md5, 1971 const struct sock *sk, 1972 const struct sk_buff *skb); 1973 int (*md5_parse)(struct sock *sk, 1974 int optname, 1975 char __user *optval, 1976 int optlen); 1977 #endif 1978 }; 1979 1980 struct tcp_request_sock_ops { 1981 u16 mss_clamp; 1982 #ifdef CONFIG_TCP_MD5SIG 1983 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 1984 const struct sock *addr_sk); 1985 int (*calc_md5_hash) (char *location, 1986 const struct tcp_md5sig_key *md5, 1987 const struct sock *sk, 1988 const struct sk_buff *skb); 1989 #endif 1990 void (*init_req)(struct request_sock *req, 1991 const struct sock *sk_listener, 1992 struct sk_buff *skb); 1993 #ifdef CONFIG_SYN_COOKIES 1994 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 1995 __u16 *mss); 1996 #endif 1997 struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl, 1998 const struct request_sock *req); 1999 u32 (*init_seq)(const struct sk_buff *skb); 2000 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2001 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2002 struct flowi *fl, struct request_sock *req, 2003 struct tcp_fastopen_cookie *foc, 2004 enum tcp_synack_type synack_type); 2005 }; 2006 2007 #ifdef CONFIG_SYN_COOKIES 2008 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2009 const struct sock *sk, struct sk_buff *skb, 2010 __u16 *mss) 2011 { 2012 tcp_synq_overflow(sk); 2013 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2014 return ops->cookie_init_seq(skb, mss); 2015 } 2016 #else 2017 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2018 const struct sock *sk, struct sk_buff *skb, 2019 __u16 *mss) 2020 { 2021 return 0; 2022 } 2023 #endif 2024 2025 int tcpv4_offload_init(void); 2026 2027 void tcp_v4_init(void); 2028 void tcp_init(void); 2029 2030 /* tcp_recovery.c */ 2031 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2032 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2033 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2034 u32 reo_wnd); 2035 extern void tcp_rack_mark_lost(struct sock *sk); 2036 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2037 u64 xmit_time); 2038 extern void tcp_rack_reo_timeout(struct sock *sk); 2039 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2040 2041 /* At how many usecs into the future should the RTO fire? */ 2042 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2043 { 2044 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2045 u32 rto = inet_csk(sk)->icsk_rto; 2046 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2047 2048 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2049 } 2050 2051 /* 2052 * Save and compile IPv4 options, return a pointer to it 2053 */ 2054 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2055 struct sk_buff *skb) 2056 { 2057 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2058 struct ip_options_rcu *dopt = NULL; 2059 2060 if (opt->optlen) { 2061 int opt_size = sizeof(*dopt) + opt->optlen; 2062 2063 dopt = kmalloc(opt_size, GFP_ATOMIC); 2064 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2065 kfree(dopt); 2066 dopt = NULL; 2067 } 2068 } 2069 return dopt; 2070 } 2071 2072 /* locally generated TCP pure ACKs have skb->truesize == 2 2073 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2074 * This is much faster than dissecting the packet to find out. 2075 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2076 */ 2077 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2078 { 2079 return skb->truesize == 2; 2080 } 2081 2082 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2083 { 2084 skb->truesize = 2; 2085 } 2086 2087 static inline int tcp_inq(struct sock *sk) 2088 { 2089 struct tcp_sock *tp = tcp_sk(sk); 2090 int answ; 2091 2092 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2093 answ = 0; 2094 } else if (sock_flag(sk, SOCK_URGINLINE) || 2095 !tp->urg_data || 2096 before(tp->urg_seq, tp->copied_seq) || 2097 !before(tp->urg_seq, tp->rcv_nxt)) { 2098 2099 answ = tp->rcv_nxt - tp->copied_seq; 2100 2101 /* Subtract 1, if FIN was received */ 2102 if (answ && sock_flag(sk, SOCK_DONE)) 2103 answ--; 2104 } else { 2105 answ = tp->urg_seq - tp->copied_seq; 2106 } 2107 2108 return answ; 2109 } 2110 2111 int tcp_peek_len(struct socket *sock); 2112 2113 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2114 { 2115 u16 segs_in; 2116 2117 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2118 tp->segs_in += segs_in; 2119 if (skb->len > tcp_hdrlen(skb)) 2120 tp->data_segs_in += segs_in; 2121 } 2122 2123 /* 2124 * TCP listen path runs lockless. 2125 * We forced "struct sock" to be const qualified to make sure 2126 * we don't modify one of its field by mistake. 2127 * Here, we increment sk_drops which is an atomic_t, so we can safely 2128 * make sock writable again. 2129 */ 2130 static inline void tcp_listendrop(const struct sock *sk) 2131 { 2132 atomic_inc(&((struct sock *)sk)->sk_drops); 2133 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2134 } 2135 2136 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2137 2138 /* 2139 * Interface for adding Upper Level Protocols over TCP 2140 */ 2141 2142 #define TCP_ULP_NAME_MAX 16 2143 #define TCP_ULP_MAX 128 2144 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2145 2146 struct tcp_ulp_ops { 2147 struct list_head list; 2148 2149 /* initialize ulp */ 2150 int (*init)(struct sock *sk); 2151 /* update ulp */ 2152 void (*update)(struct sock *sk, struct proto *p); 2153 /* cleanup ulp */ 2154 void (*release)(struct sock *sk); 2155 /* diagnostic */ 2156 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2157 size_t (*get_info_size)(const struct sock *sk); 2158 2159 char name[TCP_ULP_NAME_MAX]; 2160 struct module *owner; 2161 }; 2162 int tcp_register_ulp(struct tcp_ulp_ops *type); 2163 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2164 int tcp_set_ulp(struct sock *sk, const char *name); 2165 void tcp_get_available_ulp(char *buf, size_t len); 2166 void tcp_cleanup_ulp(struct sock *sk); 2167 void tcp_update_ulp(struct sock *sk, struct proto *p); 2168 2169 #define MODULE_ALIAS_TCP_ULP(name) \ 2170 __MODULE_INFO(alias, alias_userspace, name); \ 2171 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2172 2173 struct sk_msg; 2174 struct sk_psock; 2175 2176 int tcp_bpf_init(struct sock *sk); 2177 void tcp_bpf_reinit(struct sock *sk); 2178 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes, 2179 int flags); 2180 int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 2181 int nonblock, int flags, int *addr_len); 2182 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, 2183 struct msghdr *msg, int len, int flags); 2184 2185 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2186 * is < 0, then the BPF op failed (for example if the loaded BPF 2187 * program does not support the chosen operation or there is no BPF 2188 * program loaded). 2189 */ 2190 #ifdef CONFIG_BPF 2191 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2192 { 2193 struct bpf_sock_ops_kern sock_ops; 2194 int ret; 2195 2196 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2197 if (sk_fullsock(sk)) { 2198 sock_ops.is_fullsock = 1; 2199 sock_owned_by_me(sk); 2200 } 2201 2202 sock_ops.sk = sk; 2203 sock_ops.op = op; 2204 if (nargs > 0) 2205 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2206 2207 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2208 if (ret == 0) 2209 ret = sock_ops.reply; 2210 else 2211 ret = -1; 2212 return ret; 2213 } 2214 2215 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2216 { 2217 u32 args[2] = {arg1, arg2}; 2218 2219 return tcp_call_bpf(sk, op, 2, args); 2220 } 2221 2222 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2223 u32 arg3) 2224 { 2225 u32 args[3] = {arg1, arg2, arg3}; 2226 2227 return tcp_call_bpf(sk, op, 3, args); 2228 } 2229 2230 #else 2231 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2232 { 2233 return -EPERM; 2234 } 2235 2236 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2237 { 2238 return -EPERM; 2239 } 2240 2241 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2242 u32 arg3) 2243 { 2244 return -EPERM; 2245 } 2246 2247 #endif 2248 2249 static inline u32 tcp_timeout_init(struct sock *sk) 2250 { 2251 int timeout; 2252 2253 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2254 2255 if (timeout <= 0) 2256 timeout = TCP_TIMEOUT_INIT; 2257 return timeout; 2258 } 2259 2260 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2261 { 2262 int rwnd; 2263 2264 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2265 2266 if (rwnd < 0) 2267 rwnd = 0; 2268 return rwnd; 2269 } 2270 2271 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2272 { 2273 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2274 } 2275 2276 static inline void tcp_bpf_rtt(struct sock *sk) 2277 { 2278 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2279 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2280 } 2281 2282 #if IS_ENABLED(CONFIG_SMC) 2283 extern struct static_key_false tcp_have_smc; 2284 #endif 2285 2286 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2287 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2288 void (*cad)(struct sock *sk, u32 ack_seq)); 2289 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2290 void clean_acked_data_flush(void); 2291 #endif 2292 2293 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2294 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2295 const struct tcp_sock *tp) 2296 { 2297 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2298 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2299 } 2300 2301 /* Compute Earliest Departure Time for some control packets 2302 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2303 */ 2304 static inline u64 tcp_transmit_time(const struct sock *sk) 2305 { 2306 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2307 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2308 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2309 2310 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2311 } 2312 return 0; 2313 } 2314 2315 #endif /* _TCP_H */ 2316