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 #include <net/mptcp.h> 43 44 #include <linux/seq_file.h> 45 #include <linux/memcontrol.h> 46 #include <linux/bpf-cgroup.h> 47 #include <linux/siphash.h> 48 49 extern struct inet_hashinfo tcp_hashinfo; 50 51 extern struct percpu_counter tcp_orphan_count; 52 void tcp_time_wait(struct sock *sk, int state, int timeo); 53 54 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) 55 #define MAX_TCP_OPTION_SPACE 40 56 #define TCP_MIN_SND_MSS 48 57 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 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 initial 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_MPTCP 30 /* Multipath TCP (RFC6824) */ 187 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 188 #define TCPOPT_EXP 254 /* Experimental */ 189 /* Magic number to be after the option value for sharing TCP 190 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 191 */ 192 #define TCPOPT_FASTOPEN_MAGIC 0xF989 193 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 194 195 /* 196 * TCP option lengths 197 */ 198 199 #define TCPOLEN_MSS 4 200 #define TCPOLEN_WINDOW 3 201 #define TCPOLEN_SACK_PERM 2 202 #define TCPOLEN_TIMESTAMP 10 203 #define TCPOLEN_MD5SIG 18 204 #define TCPOLEN_FASTOPEN_BASE 2 205 #define TCPOLEN_EXP_FASTOPEN_BASE 4 206 #define TCPOLEN_EXP_SMC_BASE 6 207 208 /* But this is what stacks really send out. */ 209 #define TCPOLEN_TSTAMP_ALIGNED 12 210 #define TCPOLEN_WSCALE_ALIGNED 4 211 #define TCPOLEN_SACKPERM_ALIGNED 4 212 #define TCPOLEN_SACK_BASE 2 213 #define TCPOLEN_SACK_BASE_ALIGNED 4 214 #define TCPOLEN_SACK_PERBLOCK 8 215 #define TCPOLEN_MD5SIG_ALIGNED 20 216 #define TCPOLEN_MSS_ALIGNED 4 217 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 218 219 /* Flags in tp->nonagle */ 220 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 221 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 222 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 223 224 /* TCP thin-stream limits */ 225 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 226 227 /* TCP initial congestion window as per rfc6928 */ 228 #define TCP_INIT_CWND 10 229 230 /* Bit Flags for sysctl_tcp_fastopen */ 231 #define TFO_CLIENT_ENABLE 1 232 #define TFO_SERVER_ENABLE 2 233 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 234 235 /* Accept SYN data w/o any cookie option */ 236 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 237 238 /* Force enable TFO on all listeners, i.e., not requiring the 239 * TCP_FASTOPEN socket option. 240 */ 241 #define TFO_SERVER_WO_SOCKOPT1 0x400 242 243 244 /* sysctl variables for tcp */ 245 extern int sysctl_tcp_max_orphans; 246 extern long sysctl_tcp_mem[3]; 247 248 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 249 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 250 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 251 252 extern atomic_long_t tcp_memory_allocated; 253 extern struct percpu_counter tcp_sockets_allocated; 254 extern unsigned long tcp_memory_pressure; 255 256 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 257 static inline bool tcp_under_memory_pressure(const struct sock *sk) 258 { 259 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 260 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 261 return true; 262 263 return READ_ONCE(tcp_memory_pressure); 264 } 265 /* 266 * The next routines deal with comparing 32 bit unsigned ints 267 * and worry about wraparound (automatic with unsigned arithmetic). 268 */ 269 270 static inline bool before(__u32 seq1, __u32 seq2) 271 { 272 return (__s32)(seq1-seq2) < 0; 273 } 274 #define after(seq2, seq1) before(seq1, seq2) 275 276 /* is s2<=s1<=s3 ? */ 277 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 278 { 279 return seq3 - seq2 >= seq1 - seq2; 280 } 281 282 static inline bool tcp_out_of_memory(struct sock *sk) 283 { 284 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 285 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 286 return true; 287 return false; 288 } 289 290 void sk_forced_mem_schedule(struct sock *sk, int size); 291 292 static inline bool tcp_too_many_orphans(struct sock *sk, int shift) 293 { 294 struct percpu_counter *ocp = sk->sk_prot->orphan_count; 295 int orphans = percpu_counter_read_positive(ocp); 296 297 if (orphans << shift > sysctl_tcp_max_orphans) { 298 orphans = percpu_counter_sum_positive(ocp); 299 if (orphans << shift > sysctl_tcp_max_orphans) 300 return true; 301 } 302 return false; 303 } 304 305 bool tcp_check_oom(struct sock *sk, int shift); 306 307 308 extern struct proto tcp_prot; 309 310 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 311 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 312 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 313 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 314 315 void tcp_tasklet_init(void); 316 317 int tcp_v4_err(struct sk_buff *skb, u32); 318 319 void tcp_shutdown(struct sock *sk, int how); 320 321 int tcp_v4_early_demux(struct sk_buff *skb); 322 int tcp_v4_rcv(struct sk_buff *skb); 323 324 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 325 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 326 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 327 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, 328 int flags); 329 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, 330 size_t size, int flags); 331 ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 332 size_t size, int flags); 333 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 334 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 335 int size_goal); 336 void tcp_release_cb(struct sock *sk); 337 void tcp_wfree(struct sk_buff *skb); 338 void tcp_write_timer_handler(struct sock *sk); 339 void tcp_delack_timer_handler(struct sock *sk); 340 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); 341 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 342 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 343 void tcp_rcv_space_adjust(struct sock *sk); 344 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 345 void tcp_twsk_destructor(struct sock *sk); 346 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 347 struct pipe_inode_info *pipe, size_t len, 348 unsigned int flags); 349 350 void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks); 351 static inline void tcp_dec_quickack_mode(struct sock *sk, 352 const unsigned int pkts) 353 { 354 struct inet_connection_sock *icsk = inet_csk(sk); 355 356 if (icsk->icsk_ack.quick) { 357 if (pkts >= icsk->icsk_ack.quick) { 358 icsk->icsk_ack.quick = 0; 359 /* Leaving quickack mode we deflate ATO. */ 360 icsk->icsk_ack.ato = TCP_ATO_MIN; 361 } else 362 icsk->icsk_ack.quick -= pkts; 363 } 364 } 365 366 #define TCP_ECN_OK 1 367 #define TCP_ECN_QUEUE_CWR 2 368 #define TCP_ECN_DEMAND_CWR 4 369 #define TCP_ECN_SEEN 8 370 371 enum tcp_tw_status { 372 TCP_TW_SUCCESS = 0, 373 TCP_TW_RST = 1, 374 TCP_TW_ACK = 2, 375 TCP_TW_SYN = 3 376 }; 377 378 379 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 380 struct sk_buff *skb, 381 const struct tcphdr *th); 382 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 383 struct request_sock *req, bool fastopen, 384 bool *lost_race); 385 int tcp_child_process(struct sock *parent, struct sock *child, 386 struct sk_buff *skb); 387 void tcp_enter_loss(struct sock *sk); 388 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int flag); 389 void tcp_clear_retrans(struct tcp_sock *tp); 390 void tcp_update_metrics(struct sock *sk); 391 void tcp_init_metrics(struct sock *sk); 392 void tcp_metrics_init(void); 393 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 394 void tcp_close(struct sock *sk, long timeout); 395 void tcp_init_sock(struct sock *sk); 396 void tcp_init_transfer(struct sock *sk, int bpf_op); 397 __poll_t tcp_poll(struct file *file, struct socket *sock, 398 struct poll_table_struct *wait); 399 int tcp_getsockopt(struct sock *sk, int level, int optname, 400 char __user *optval, int __user *optlen); 401 int tcp_setsockopt(struct sock *sk, int level, int optname, 402 char __user *optval, unsigned int optlen); 403 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 404 char __user *optval, int __user *optlen); 405 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 406 char __user *optval, unsigned int optlen); 407 void tcp_set_keepalive(struct sock *sk, int val); 408 void tcp_syn_ack_timeout(const struct request_sock *req); 409 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 410 int flags, int *addr_len); 411 int tcp_set_rcvlowat(struct sock *sk, int val); 412 void tcp_data_ready(struct sock *sk); 413 #ifdef CONFIG_MMU 414 int tcp_mmap(struct file *file, struct socket *sock, 415 struct vm_area_struct *vma); 416 #endif 417 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 418 struct tcp_options_received *opt_rx, 419 int estab, struct tcp_fastopen_cookie *foc); 420 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); 421 422 /* 423 * BPF SKB-less helpers 424 */ 425 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 426 struct tcphdr *th, u32 *cookie); 427 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 428 struct tcphdr *th, u32 *cookie); 429 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 430 const struct tcp_request_sock_ops *af_ops, 431 struct sock *sk, struct tcphdr *th); 432 /* 433 * TCP v4 functions exported for the inet6 API 434 */ 435 436 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 437 void tcp_v4_mtu_reduced(struct sock *sk); 438 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 439 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 440 struct sock *tcp_create_openreq_child(const struct sock *sk, 441 struct request_sock *req, 442 struct sk_buff *skb); 443 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 444 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 445 struct request_sock *req, 446 struct dst_entry *dst, 447 struct request_sock *req_unhash, 448 bool *own_req); 449 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 450 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 451 int tcp_connect(struct sock *sk); 452 enum tcp_synack_type { 453 TCP_SYNACK_NORMAL, 454 TCP_SYNACK_FASTOPEN, 455 TCP_SYNACK_COOKIE, 456 }; 457 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 458 struct request_sock *req, 459 struct tcp_fastopen_cookie *foc, 460 enum tcp_synack_type synack_type); 461 int tcp_disconnect(struct sock *sk, int flags); 462 463 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 464 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 465 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 466 467 /* From syncookies.c */ 468 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 469 struct request_sock *req, 470 struct dst_entry *dst, u32 tsoff); 471 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, 472 u32 cookie); 473 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 474 #ifdef CONFIG_SYN_COOKIES 475 476 /* Syncookies use a monotonic timer which increments every 60 seconds. 477 * This counter is used both as a hash input and partially encoded into 478 * the cookie value. A cookie is only validated further if the delta 479 * between the current counter value and the encoded one is less than this, 480 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 481 * the counter advances immediately after a cookie is generated). 482 */ 483 #define MAX_SYNCOOKIE_AGE 2 484 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 485 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 486 487 /* syncookies: remember time of last synqueue overflow 488 * But do not dirty this field too often (once per second is enough) 489 * It is racy as we do not hold a lock, but race is very minor. 490 */ 491 static inline void tcp_synq_overflow(const struct sock *sk) 492 { 493 unsigned int last_overflow; 494 unsigned int now = jiffies; 495 496 if (sk->sk_reuseport) { 497 struct sock_reuseport *reuse; 498 499 reuse = rcu_dereference(sk->sk_reuseport_cb); 500 if (likely(reuse)) { 501 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 502 if (!time_between32(now, last_overflow, 503 last_overflow + HZ)) 504 WRITE_ONCE(reuse->synq_overflow_ts, now); 505 return; 506 } 507 } 508 509 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 510 if (!time_between32(now, last_overflow, last_overflow + HZ)) 511 WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now); 512 } 513 514 /* syncookies: no recent synqueue overflow on this listening socket? */ 515 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 516 { 517 unsigned int last_overflow; 518 unsigned int now = jiffies; 519 520 if (sk->sk_reuseport) { 521 struct sock_reuseport *reuse; 522 523 reuse = rcu_dereference(sk->sk_reuseport_cb); 524 if (likely(reuse)) { 525 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 526 return !time_between32(now, last_overflow - HZ, 527 last_overflow + 528 TCP_SYNCOOKIE_VALID); 529 } 530 } 531 532 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 533 534 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 535 * then we're under synflood. However, we have to use 536 * 'last_overflow - HZ' as lower bound. That's because a concurrent 537 * tcp_synq_overflow() could update .ts_recent_stamp after we read 538 * jiffies but before we store .ts_recent_stamp into last_overflow, 539 * which could lead to rejecting a valid syncookie. 540 */ 541 return !time_between32(now, last_overflow - HZ, 542 last_overflow + TCP_SYNCOOKIE_VALID); 543 } 544 545 static inline u32 tcp_cookie_time(void) 546 { 547 u64 val = get_jiffies_64(); 548 549 do_div(val, TCP_SYNCOOKIE_PERIOD); 550 return val; 551 } 552 553 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 554 u16 *mssp); 555 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 556 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 557 bool cookie_timestamp_decode(const struct net *net, 558 struct tcp_options_received *opt); 559 bool cookie_ecn_ok(const struct tcp_options_received *opt, 560 const struct net *net, const struct dst_entry *dst); 561 562 /* From net/ipv6/syncookies.c */ 563 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, 564 u32 cookie); 565 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 566 567 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 568 const struct tcphdr *th, u16 *mssp); 569 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 570 #endif 571 /* tcp_output.c */ 572 573 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 574 int nonagle); 575 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 576 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 577 void tcp_retransmit_timer(struct sock *sk); 578 void tcp_xmit_retransmit_queue(struct sock *); 579 void tcp_simple_retransmit(struct sock *); 580 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 581 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 582 enum tcp_queue { 583 TCP_FRAG_IN_WRITE_QUEUE, 584 TCP_FRAG_IN_RTX_QUEUE, 585 }; 586 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 587 struct sk_buff *skb, u32 len, 588 unsigned int mss_now, gfp_t gfp); 589 590 void tcp_send_probe0(struct sock *); 591 void tcp_send_partial(struct sock *); 592 int tcp_write_wakeup(struct sock *, int mib); 593 void tcp_send_fin(struct sock *sk); 594 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 595 int tcp_send_synack(struct sock *); 596 void tcp_push_one(struct sock *, unsigned int mss_now); 597 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 598 void tcp_send_ack(struct sock *sk); 599 void tcp_send_delayed_ack(struct sock *sk); 600 void tcp_send_loss_probe(struct sock *sk); 601 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 602 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 603 const struct sk_buff *next_skb); 604 605 /* tcp_input.c */ 606 void tcp_rearm_rto(struct sock *sk); 607 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 608 void tcp_reset(struct sock *sk); 609 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb); 610 void tcp_fin(struct sock *sk); 611 612 /* tcp_timer.c */ 613 void tcp_init_xmit_timers(struct sock *); 614 static inline void tcp_clear_xmit_timers(struct sock *sk) 615 { 616 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 617 __sock_put(sk); 618 619 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 620 __sock_put(sk); 621 622 inet_csk_clear_xmit_timers(sk); 623 } 624 625 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 626 unsigned int tcp_current_mss(struct sock *sk); 627 628 /* Bound MSS / TSO packet size with the half of the window */ 629 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 630 { 631 int cutoff; 632 633 /* When peer uses tiny windows, there is no use in packetizing 634 * to sub-MSS pieces for the sake of SWS or making sure there 635 * are enough packets in the pipe for fast recovery. 636 * 637 * On the other hand, for extremely large MSS devices, handling 638 * smaller than MSS windows in this way does make sense. 639 */ 640 if (tp->max_window > TCP_MSS_DEFAULT) 641 cutoff = (tp->max_window >> 1); 642 else 643 cutoff = tp->max_window; 644 645 if (cutoff && pktsize > cutoff) 646 return max_t(int, cutoff, 68U - tp->tcp_header_len); 647 else 648 return pktsize; 649 } 650 651 /* tcp.c */ 652 void tcp_get_info(struct sock *, struct tcp_info *); 653 654 /* Read 'sendfile()'-style from a TCP socket */ 655 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 656 sk_read_actor_t recv_actor); 657 658 void tcp_initialize_rcv_mss(struct sock *sk); 659 660 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 661 int tcp_mss_to_mtu(struct sock *sk, int mss); 662 void tcp_mtup_init(struct sock *sk); 663 void tcp_init_buffer_space(struct sock *sk); 664 665 static inline void tcp_bound_rto(const struct sock *sk) 666 { 667 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 668 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 669 } 670 671 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 672 { 673 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 674 } 675 676 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 677 { 678 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 679 ntohl(TCP_FLAG_ACK) | 680 snd_wnd); 681 } 682 683 static inline void tcp_fast_path_on(struct tcp_sock *tp) 684 { 685 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 686 } 687 688 static inline void tcp_fast_path_check(struct sock *sk) 689 { 690 struct tcp_sock *tp = tcp_sk(sk); 691 692 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 693 tp->rcv_wnd && 694 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 695 !tp->urg_data) 696 tcp_fast_path_on(tp); 697 } 698 699 /* Compute the actual rto_min value */ 700 static inline u32 tcp_rto_min(struct sock *sk) 701 { 702 const struct dst_entry *dst = __sk_dst_get(sk); 703 u32 rto_min = TCP_RTO_MIN; 704 705 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 706 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 707 return rto_min; 708 } 709 710 static inline u32 tcp_rto_min_us(struct sock *sk) 711 { 712 return jiffies_to_usecs(tcp_rto_min(sk)); 713 } 714 715 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 716 { 717 return dst_metric_locked(dst, RTAX_CC_ALGO); 718 } 719 720 /* Minimum RTT in usec. ~0 means not available. */ 721 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 722 { 723 return minmax_get(&tp->rtt_min); 724 } 725 726 /* Compute the actual receive window we are currently advertising. 727 * Rcv_nxt can be after the window if our peer push more data 728 * than the offered window. 729 */ 730 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 731 { 732 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 733 734 if (win < 0) 735 win = 0; 736 return (u32) win; 737 } 738 739 /* Choose a new window, without checks for shrinking, and without 740 * scaling applied to the result. The caller does these things 741 * if necessary. This is a "raw" window selection. 742 */ 743 u32 __tcp_select_window(struct sock *sk); 744 745 void tcp_send_window_probe(struct sock *sk); 746 747 /* TCP uses 32bit jiffies to save some space. 748 * Note that this is different from tcp_time_stamp, which 749 * historically has been the same until linux-4.13. 750 */ 751 #define tcp_jiffies32 ((u32)jiffies) 752 753 /* 754 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 755 * It is no longer tied to jiffies, but to 1 ms clock. 756 * Note: double check if you want to use tcp_jiffies32 instead of this. 757 */ 758 #define TCP_TS_HZ 1000 759 760 static inline u64 tcp_clock_ns(void) 761 { 762 return ktime_get_ns(); 763 } 764 765 static inline u64 tcp_clock_us(void) 766 { 767 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 768 } 769 770 /* This should only be used in contexts where tp->tcp_mstamp is up to date */ 771 static inline u32 tcp_time_stamp(const struct tcp_sock *tp) 772 { 773 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); 774 } 775 776 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ 777 static inline u32 tcp_ns_to_ts(u64 ns) 778 { 779 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); 780 } 781 782 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ 783 static inline u32 tcp_time_stamp_raw(void) 784 { 785 return tcp_ns_to_ts(tcp_clock_ns()); 786 } 787 788 void tcp_mstamp_refresh(struct tcp_sock *tp); 789 790 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 791 { 792 return max_t(s64, t1 - t0, 0); 793 } 794 795 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 796 { 797 return tcp_ns_to_ts(skb->skb_mstamp_ns); 798 } 799 800 /* provide the departure time in us unit */ 801 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 802 { 803 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 804 } 805 806 807 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 808 809 #define TCPHDR_FIN 0x01 810 #define TCPHDR_SYN 0x02 811 #define TCPHDR_RST 0x04 812 #define TCPHDR_PSH 0x08 813 #define TCPHDR_ACK 0x10 814 #define TCPHDR_URG 0x20 815 #define TCPHDR_ECE 0x40 816 #define TCPHDR_CWR 0x80 817 818 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 819 820 /* This is what the send packet queuing engine uses to pass 821 * TCP per-packet control information to the transmission code. 822 * We also store the host-order sequence numbers in here too. 823 * This is 44 bytes if IPV6 is enabled. 824 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 825 */ 826 struct tcp_skb_cb { 827 __u32 seq; /* Starting sequence number */ 828 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 829 union { 830 /* Note : tcp_tw_isn is used in input path only 831 * (isn chosen by tcp_timewait_state_process()) 832 * 833 * tcp_gso_segs/size are used in write queue only, 834 * cf tcp_skb_pcount()/tcp_skb_mss() 835 */ 836 __u32 tcp_tw_isn; 837 struct { 838 u16 tcp_gso_segs; 839 u16 tcp_gso_size; 840 }; 841 }; 842 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 843 844 __u8 sacked; /* State flags for SACK. */ 845 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 846 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 847 #define TCPCB_LOST 0x04 /* SKB is lost */ 848 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 849 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 850 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 851 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 852 TCPCB_REPAIRED) 853 854 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 855 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 856 eor:1, /* Is skb MSG_EOR marked? */ 857 has_rxtstamp:1, /* SKB has a RX timestamp */ 858 unused:5; 859 __u32 ack_seq; /* Sequence number ACK'd */ 860 union { 861 struct { 862 /* There is space for up to 24 bytes */ 863 __u32 in_flight:30,/* Bytes in flight at transmit */ 864 is_app_limited:1, /* cwnd not fully used? */ 865 unused:1; 866 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 867 __u32 delivered; 868 /* start of send pipeline phase */ 869 u64 first_tx_mstamp; 870 /* when we reached the "delivered" count */ 871 u64 delivered_mstamp; 872 } tx; /* only used for outgoing skbs */ 873 union { 874 struct inet_skb_parm h4; 875 #if IS_ENABLED(CONFIG_IPV6) 876 struct inet6_skb_parm h6; 877 #endif 878 } header; /* For incoming skbs */ 879 struct { 880 __u32 flags; 881 struct sock *sk_redir; 882 void *data_end; 883 } bpf; 884 }; 885 }; 886 887 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 888 889 static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb) 890 { 891 TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb); 892 } 893 894 static inline bool tcp_skb_bpf_ingress(const struct sk_buff *skb) 895 { 896 return TCP_SKB_CB(skb)->bpf.flags & BPF_F_INGRESS; 897 } 898 899 static inline struct sock *tcp_skb_bpf_redirect_fetch(struct sk_buff *skb) 900 { 901 return TCP_SKB_CB(skb)->bpf.sk_redir; 902 } 903 904 static inline void tcp_skb_bpf_redirect_clear(struct sk_buff *skb) 905 { 906 TCP_SKB_CB(skb)->bpf.sk_redir = NULL; 907 } 908 909 #if IS_ENABLED(CONFIG_IPV6) 910 /* This is the variant of inet6_iif() that must be used by TCP, 911 * as TCP moves IP6CB into a different location in skb->cb[] 912 */ 913 static inline int tcp_v6_iif(const struct sk_buff *skb) 914 { 915 return TCP_SKB_CB(skb)->header.h6.iif; 916 } 917 918 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 919 { 920 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 921 922 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 923 } 924 925 /* TCP_SKB_CB reference means this can not be used from early demux */ 926 static inline int tcp_v6_sdif(const struct sk_buff *skb) 927 { 928 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 929 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 930 return TCP_SKB_CB(skb)->header.h6.iif; 931 #endif 932 return 0; 933 } 934 #endif 935 936 static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb) 937 { 938 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 939 if (!net->ipv4.sysctl_tcp_l3mdev_accept && 940 skb && ipv4_l3mdev_skb(IPCB(skb)->flags)) 941 return true; 942 #endif 943 return false; 944 } 945 946 /* TCP_SKB_CB reference means this can not be used from early demux */ 947 static inline int tcp_v4_sdif(struct sk_buff *skb) 948 { 949 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 950 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 951 return TCP_SKB_CB(skb)->header.h4.iif; 952 #endif 953 return 0; 954 } 955 956 /* Due to TSO, an SKB can be composed of multiple actual 957 * packets. To keep these tracked properly, we use this. 958 */ 959 static inline int tcp_skb_pcount(const struct sk_buff *skb) 960 { 961 return TCP_SKB_CB(skb)->tcp_gso_segs; 962 } 963 964 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 965 { 966 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 967 } 968 969 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 970 { 971 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 972 } 973 974 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 975 static inline int tcp_skb_mss(const struct sk_buff *skb) 976 { 977 return TCP_SKB_CB(skb)->tcp_gso_size; 978 } 979 980 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 981 { 982 return likely(!TCP_SKB_CB(skb)->eor); 983 } 984 985 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 986 const struct sk_buff *from) 987 { 988 return likely(tcp_skb_can_collapse_to(to) && 989 mptcp_skb_can_collapse(to, from)); 990 } 991 992 /* Events passed to congestion control interface */ 993 enum tcp_ca_event { 994 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 995 CA_EVENT_CWND_RESTART, /* congestion window restart */ 996 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 997 CA_EVENT_LOSS, /* loss timeout */ 998 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 999 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 1000 }; 1001 1002 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1003 enum tcp_ca_ack_event_flags { 1004 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1005 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1006 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1007 }; 1008 1009 /* 1010 * Interface for adding new TCP congestion control handlers 1011 */ 1012 #define TCP_CA_NAME_MAX 16 1013 #define TCP_CA_MAX 128 1014 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1015 1016 #define TCP_CA_UNSPEC 0 1017 1018 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1019 #define TCP_CONG_NON_RESTRICTED 0x1 1020 /* Requires ECN/ECT set on all packets */ 1021 #define TCP_CONG_NEEDS_ECN 0x2 1022 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1023 1024 union tcp_cc_info; 1025 1026 struct ack_sample { 1027 u32 pkts_acked; 1028 s32 rtt_us; 1029 u32 in_flight; 1030 }; 1031 1032 /* A rate sample measures the number of (original/retransmitted) data 1033 * packets delivered "delivered" over an interval of time "interval_us". 1034 * The tcp_rate.c code fills in the rate sample, and congestion 1035 * control modules that define a cong_control function to run at the end 1036 * of ACK processing can optionally chose to consult this sample when 1037 * setting cwnd and pacing rate. 1038 * A sample is invalid if "delivered" or "interval_us" is negative. 1039 */ 1040 struct rate_sample { 1041 u64 prior_mstamp; /* starting timestamp for interval */ 1042 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1043 s32 delivered; /* number of packets delivered over interval */ 1044 long interval_us; /* time for tp->delivered to incr "delivered" */ 1045 u32 snd_interval_us; /* snd interval for delivered packets */ 1046 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1047 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1048 int losses; /* number of packets marked lost upon ACK */ 1049 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1050 u32 prior_in_flight; /* in flight before this ACK */ 1051 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1052 bool is_retrans; /* is sample from retransmission? */ 1053 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1054 }; 1055 1056 struct tcp_congestion_ops { 1057 struct list_head list; 1058 u32 key; 1059 u32 flags; 1060 1061 /* initialize private data (optional) */ 1062 void (*init)(struct sock *sk); 1063 /* cleanup private data (optional) */ 1064 void (*release)(struct sock *sk); 1065 1066 /* return slow start threshold (required) */ 1067 u32 (*ssthresh)(struct sock *sk); 1068 /* do new cwnd calculation (required) */ 1069 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1070 /* call before changing ca_state (optional) */ 1071 void (*set_state)(struct sock *sk, u8 new_state); 1072 /* call when cwnd event occurs (optional) */ 1073 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1074 /* call when ack arrives (optional) */ 1075 void (*in_ack_event)(struct sock *sk, u32 flags); 1076 /* new value of cwnd after loss (required) */ 1077 u32 (*undo_cwnd)(struct sock *sk); 1078 /* hook for packet ack accounting (optional) */ 1079 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1080 /* override sysctl_tcp_min_tso_segs */ 1081 u32 (*min_tso_segs)(struct sock *sk); 1082 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1083 u32 (*sndbuf_expand)(struct sock *sk); 1084 /* call when packets are delivered to update cwnd and pacing rate, 1085 * after all the ca_state processing. (optional) 1086 */ 1087 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1088 /* get info for inet_diag (optional) */ 1089 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1090 union tcp_cc_info *info); 1091 1092 char name[TCP_CA_NAME_MAX]; 1093 struct module *owner; 1094 }; 1095 1096 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1097 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1098 1099 void tcp_assign_congestion_control(struct sock *sk); 1100 void tcp_init_congestion_control(struct sock *sk); 1101 void tcp_cleanup_congestion_control(struct sock *sk); 1102 int tcp_set_default_congestion_control(struct net *net, const char *name); 1103 void tcp_get_default_congestion_control(struct net *net, char *name); 1104 void tcp_get_available_congestion_control(char *buf, size_t len); 1105 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1106 int tcp_set_allowed_congestion_control(char *allowed); 1107 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1108 bool reinit, bool cap_net_admin); 1109 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1110 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1111 1112 u32 tcp_reno_ssthresh(struct sock *sk); 1113 u32 tcp_reno_undo_cwnd(struct sock *sk); 1114 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1115 extern struct tcp_congestion_ops tcp_reno; 1116 1117 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1118 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1119 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1120 #ifdef CONFIG_INET 1121 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1122 #else 1123 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1124 { 1125 return NULL; 1126 } 1127 #endif 1128 1129 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1130 { 1131 const struct inet_connection_sock *icsk = inet_csk(sk); 1132 1133 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1134 } 1135 1136 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 1137 { 1138 struct inet_connection_sock *icsk = inet_csk(sk); 1139 1140 if (icsk->icsk_ca_ops->set_state) 1141 icsk->icsk_ca_ops->set_state(sk, ca_state); 1142 icsk->icsk_ca_state = ca_state; 1143 } 1144 1145 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1146 { 1147 const struct inet_connection_sock *icsk = inet_csk(sk); 1148 1149 if (icsk->icsk_ca_ops->cwnd_event) 1150 icsk->icsk_ca_ops->cwnd_event(sk, event); 1151 } 1152 1153 /* From tcp_rate.c */ 1154 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1155 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1156 struct rate_sample *rs); 1157 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1158 bool is_sack_reneg, struct rate_sample *rs); 1159 void tcp_rate_check_app_limited(struct sock *sk); 1160 1161 /* These functions determine how the current flow behaves in respect of SACK 1162 * handling. SACK is negotiated with the peer, and therefore it can vary 1163 * between different flows. 1164 * 1165 * tcp_is_sack - SACK enabled 1166 * tcp_is_reno - No SACK 1167 */ 1168 static inline int tcp_is_sack(const struct tcp_sock *tp) 1169 { 1170 return likely(tp->rx_opt.sack_ok); 1171 } 1172 1173 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1174 { 1175 return !tcp_is_sack(tp); 1176 } 1177 1178 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1179 { 1180 return tp->sacked_out + tp->lost_out; 1181 } 1182 1183 /* This determines how many packets are "in the network" to the best 1184 * of our knowledge. In many cases it is conservative, but where 1185 * detailed information is available from the receiver (via SACK 1186 * blocks etc.) we can make more aggressive calculations. 1187 * 1188 * Use this for decisions involving congestion control, use just 1189 * tp->packets_out to determine if the send queue is empty or not. 1190 * 1191 * Read this equation as: 1192 * 1193 * "Packets sent once on transmission queue" MINUS 1194 * "Packets left network, but not honestly ACKed yet" PLUS 1195 * "Packets fast retransmitted" 1196 */ 1197 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1198 { 1199 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1200 } 1201 1202 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1203 1204 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1205 { 1206 return tp->snd_cwnd < tp->snd_ssthresh; 1207 } 1208 1209 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1210 { 1211 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1212 } 1213 1214 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1215 { 1216 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1217 (1 << inet_csk(sk)->icsk_ca_state); 1218 } 1219 1220 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1221 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1222 * ssthresh. 1223 */ 1224 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1225 { 1226 const struct tcp_sock *tp = tcp_sk(sk); 1227 1228 if (tcp_in_cwnd_reduction(sk)) 1229 return tp->snd_ssthresh; 1230 else 1231 return max(tp->snd_ssthresh, 1232 ((tp->snd_cwnd >> 1) + 1233 (tp->snd_cwnd >> 2))); 1234 } 1235 1236 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1237 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1238 1239 void tcp_enter_cwr(struct sock *sk); 1240 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1241 1242 /* The maximum number of MSS of available cwnd for which TSO defers 1243 * sending if not using sysctl_tcp_tso_win_divisor. 1244 */ 1245 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1246 { 1247 return 3; 1248 } 1249 1250 /* Returns end sequence number of the receiver's advertised window */ 1251 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1252 { 1253 return tp->snd_una + tp->snd_wnd; 1254 } 1255 1256 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1257 * flexible approach. The RFC suggests cwnd should not be raised unless 1258 * it was fully used previously. And that's exactly what we do in 1259 * congestion avoidance mode. But in slow start we allow cwnd to grow 1260 * as long as the application has used half the cwnd. 1261 * Example : 1262 * cwnd is 10 (IW10), but application sends 9 frames. 1263 * We allow cwnd to reach 18 when all frames are ACKed. 1264 * This check is safe because it's as aggressive as slow start which already 1265 * risks 100% overshoot. The advantage is that we discourage application to 1266 * either send more filler packets or data to artificially blow up the cwnd 1267 * usage, and allow application-limited process to probe bw more aggressively. 1268 */ 1269 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1270 { 1271 const struct tcp_sock *tp = tcp_sk(sk); 1272 1273 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1274 if (tcp_in_slow_start(tp)) 1275 return tp->snd_cwnd < 2 * tp->max_packets_out; 1276 1277 return tp->is_cwnd_limited; 1278 } 1279 1280 /* BBR congestion control needs pacing. 1281 * Same remark for SO_MAX_PACING_RATE. 1282 * sch_fq packet scheduler is efficiently handling pacing, 1283 * but is not always installed/used. 1284 * Return true if TCP stack should pace packets itself. 1285 */ 1286 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1287 { 1288 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1289 } 1290 1291 /* Return in jiffies the delay before one skb is sent. 1292 * If @skb is NULL, we look at EDT for next packet being sent on the socket. 1293 */ 1294 static inline unsigned long tcp_pacing_delay(const struct sock *sk, 1295 const struct sk_buff *skb) 1296 { 1297 s64 pacing_delay = skb ? skb->tstamp : tcp_sk(sk)->tcp_wstamp_ns; 1298 1299 pacing_delay -= tcp_sk(sk)->tcp_clock_cache; 1300 1301 return pacing_delay > 0 ? nsecs_to_jiffies(pacing_delay) : 0; 1302 } 1303 1304 static inline void tcp_reset_xmit_timer(struct sock *sk, 1305 const int what, 1306 unsigned long when, 1307 const unsigned long max_when, 1308 const struct sk_buff *skb) 1309 { 1310 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk, skb), 1311 max_when); 1312 } 1313 1314 /* Something is really bad, we could not queue an additional packet, 1315 * because qdisc is full or receiver sent a 0 window, or we are paced. 1316 * We do not want to add fuel to the fire, or abort too early, 1317 * so make sure the timer we arm now is at least 200ms in the future, 1318 * regardless of current icsk_rto value (as it could be ~2ms) 1319 */ 1320 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1321 { 1322 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1323 } 1324 1325 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1326 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1327 unsigned long max_when) 1328 { 1329 u64 when = (u64)tcp_probe0_base(sk) << inet_csk(sk)->icsk_backoff; 1330 1331 return (unsigned long)min_t(u64, when, max_when); 1332 } 1333 1334 static inline void tcp_check_probe_timer(struct sock *sk) 1335 { 1336 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1337 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1338 tcp_probe0_base(sk), TCP_RTO_MAX, 1339 NULL); 1340 } 1341 1342 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1343 { 1344 tp->snd_wl1 = seq; 1345 } 1346 1347 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1348 { 1349 tp->snd_wl1 = seq; 1350 } 1351 1352 /* 1353 * Calculate(/check) TCP checksum 1354 */ 1355 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1356 __be32 daddr, __wsum base) 1357 { 1358 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1359 } 1360 1361 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1362 { 1363 return !skb_csum_unnecessary(skb) && 1364 __skb_checksum_complete(skb); 1365 } 1366 1367 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); 1368 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1369 void tcp_set_state(struct sock *sk, int state); 1370 void tcp_done(struct sock *sk); 1371 int tcp_abort(struct sock *sk, int err); 1372 1373 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1374 { 1375 rx_opt->dsack = 0; 1376 rx_opt->num_sacks = 0; 1377 } 1378 1379 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1380 1381 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1382 { 1383 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1384 struct tcp_sock *tp = tcp_sk(sk); 1385 s32 delta; 1386 1387 if (!sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle || tp->packets_out || 1388 ca_ops->cong_control) 1389 return; 1390 delta = tcp_jiffies32 - tp->lsndtime; 1391 if (delta > inet_csk(sk)->icsk_rto) 1392 tcp_cwnd_restart(sk, delta); 1393 } 1394 1395 /* Determine a window scaling and initial window to offer. */ 1396 void tcp_select_initial_window(const struct sock *sk, int __space, 1397 __u32 mss, __u32 *rcv_wnd, 1398 __u32 *window_clamp, int wscale_ok, 1399 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1400 1401 static inline int tcp_win_from_space(const struct sock *sk, int space) 1402 { 1403 int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; 1404 1405 return tcp_adv_win_scale <= 0 ? 1406 (space>>(-tcp_adv_win_scale)) : 1407 space - (space>>tcp_adv_win_scale); 1408 } 1409 1410 /* Note: caller must be prepared to deal with negative returns */ 1411 static inline int tcp_space(const struct sock *sk) 1412 { 1413 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1414 READ_ONCE(sk->sk_backlog.len) - 1415 atomic_read(&sk->sk_rmem_alloc)); 1416 } 1417 1418 static inline int tcp_full_space(const struct sock *sk) 1419 { 1420 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1421 } 1422 1423 extern void tcp_openreq_init_rwin(struct request_sock *req, 1424 const struct sock *sk_listener, 1425 const struct dst_entry *dst); 1426 1427 void tcp_enter_memory_pressure(struct sock *sk); 1428 void tcp_leave_memory_pressure(struct sock *sk); 1429 1430 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1431 { 1432 struct net *net = sock_net((struct sock *)tp); 1433 1434 return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl; 1435 } 1436 1437 static inline int keepalive_time_when(const struct tcp_sock *tp) 1438 { 1439 struct net *net = sock_net((struct sock *)tp); 1440 1441 return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time; 1442 } 1443 1444 static inline int keepalive_probes(const struct tcp_sock *tp) 1445 { 1446 struct net *net = sock_net((struct sock *)tp); 1447 1448 return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes; 1449 } 1450 1451 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1452 { 1453 const struct inet_connection_sock *icsk = &tp->inet_conn; 1454 1455 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1456 tcp_jiffies32 - tp->rcv_tstamp); 1457 } 1458 1459 static inline int tcp_fin_time(const struct sock *sk) 1460 { 1461 int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout; 1462 const int rto = inet_csk(sk)->icsk_rto; 1463 1464 if (fin_timeout < (rto << 2) - (rto >> 1)) 1465 fin_timeout = (rto << 2) - (rto >> 1); 1466 1467 return fin_timeout; 1468 } 1469 1470 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1471 int paws_win) 1472 { 1473 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1474 return true; 1475 if (unlikely(!time_before32(ktime_get_seconds(), 1476 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1477 return true; 1478 /* 1479 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1480 * then following tcp messages have valid values. Ignore 0 value, 1481 * or else 'negative' tsval might forbid us to accept their packets. 1482 */ 1483 if (!rx_opt->ts_recent) 1484 return true; 1485 return false; 1486 } 1487 1488 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1489 int rst) 1490 { 1491 if (tcp_paws_check(rx_opt, 0)) 1492 return false; 1493 1494 /* RST segments are not recommended to carry timestamp, 1495 and, if they do, it is recommended to ignore PAWS because 1496 "their cleanup function should take precedence over timestamps." 1497 Certainly, it is mistake. It is necessary to understand the reasons 1498 of this constraint to relax it: if peer reboots, clock may go 1499 out-of-sync and half-open connections will not be reset. 1500 Actually, the problem would be not existing if all 1501 the implementations followed draft about maintaining clock 1502 via reboots. Linux-2.2 DOES NOT! 1503 1504 However, we can relax time bounds for RST segments to MSL. 1505 */ 1506 if (rst && !time_before32(ktime_get_seconds(), 1507 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1508 return false; 1509 return true; 1510 } 1511 1512 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1513 int mib_idx, u32 *last_oow_ack_time); 1514 1515 static inline void tcp_mib_init(struct net *net) 1516 { 1517 /* See RFC 2012 */ 1518 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1519 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1520 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1521 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1522 } 1523 1524 /* from STCP */ 1525 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1526 { 1527 tp->lost_skb_hint = NULL; 1528 } 1529 1530 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1531 { 1532 tcp_clear_retrans_hints_partial(tp); 1533 tp->retransmit_skb_hint = NULL; 1534 } 1535 1536 union tcp_md5_addr { 1537 struct in_addr a4; 1538 #if IS_ENABLED(CONFIG_IPV6) 1539 struct in6_addr a6; 1540 #endif 1541 }; 1542 1543 /* - key database */ 1544 struct tcp_md5sig_key { 1545 struct hlist_node node; 1546 u8 keylen; 1547 u8 family; /* AF_INET or AF_INET6 */ 1548 u8 prefixlen; 1549 union tcp_md5_addr addr; 1550 int l3index; /* set if key added with L3 scope */ 1551 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1552 struct rcu_head rcu; 1553 }; 1554 1555 /* - sock block */ 1556 struct tcp_md5sig_info { 1557 struct hlist_head head; 1558 struct rcu_head rcu; 1559 }; 1560 1561 /* - pseudo header */ 1562 struct tcp4_pseudohdr { 1563 __be32 saddr; 1564 __be32 daddr; 1565 __u8 pad; 1566 __u8 protocol; 1567 __be16 len; 1568 }; 1569 1570 struct tcp6_pseudohdr { 1571 struct in6_addr saddr; 1572 struct in6_addr daddr; 1573 __be32 len; 1574 __be32 protocol; /* including padding */ 1575 }; 1576 1577 union tcp_md5sum_block { 1578 struct tcp4_pseudohdr ip4; 1579 #if IS_ENABLED(CONFIG_IPV6) 1580 struct tcp6_pseudohdr ip6; 1581 #endif 1582 }; 1583 1584 /* - pool: digest algorithm, hash description and scratch buffer */ 1585 struct tcp_md5sig_pool { 1586 struct ahash_request *md5_req; 1587 void *scratch; 1588 }; 1589 1590 /* - functions */ 1591 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1592 const struct sock *sk, const struct sk_buff *skb); 1593 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1594 int family, u8 prefixlen, int l3index, 1595 const u8 *newkey, u8 newkeylen, gfp_t gfp); 1596 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1597 int family, u8 prefixlen, int l3index); 1598 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1599 const struct sock *addr_sk); 1600 1601 #ifdef CONFIG_TCP_MD5SIG 1602 #include <linux/jump_label.h> 1603 extern struct static_key_false tcp_md5_needed; 1604 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1605 const union tcp_md5_addr *addr, 1606 int family); 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 if (!static_branch_unlikely(&tcp_md5_needed)) 1612 return NULL; 1613 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1614 } 1615 1616 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1617 #else 1618 static inline struct tcp_md5sig_key * 1619 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1620 const union tcp_md5_addr *addr, int family) 1621 { 1622 return NULL; 1623 } 1624 #define tcp_twsk_md5_key(twsk) NULL 1625 #endif 1626 1627 bool tcp_alloc_md5sig_pool(void); 1628 1629 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1630 static inline void tcp_put_md5sig_pool(void) 1631 { 1632 local_bh_enable(); 1633 } 1634 1635 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1636 unsigned int header_len); 1637 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1638 const struct tcp_md5sig_key *key); 1639 1640 /* From tcp_fastopen.c */ 1641 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1642 struct tcp_fastopen_cookie *cookie); 1643 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1644 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1645 u16 try_exp); 1646 struct tcp_fastopen_request { 1647 /* Fast Open cookie. Size 0 means a cookie request */ 1648 struct tcp_fastopen_cookie cookie; 1649 struct msghdr *data; /* data in MSG_FASTOPEN */ 1650 size_t size; 1651 int copied; /* queued in tcp_connect() */ 1652 struct ubuf_info *uarg; 1653 }; 1654 void tcp_free_fastopen_req(struct tcp_sock *tp); 1655 void tcp_fastopen_destroy_cipher(struct sock *sk); 1656 void tcp_fastopen_ctx_destroy(struct net *net); 1657 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1658 void *primary_key, void *backup_key); 1659 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1660 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1661 struct request_sock *req, 1662 struct tcp_fastopen_cookie *foc, 1663 const struct dst_entry *dst); 1664 void tcp_fastopen_init_key_once(struct net *net); 1665 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1666 struct tcp_fastopen_cookie *cookie); 1667 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1668 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1669 #define TCP_FASTOPEN_KEY_MAX 2 1670 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1671 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1672 1673 /* Fastopen key context */ 1674 struct tcp_fastopen_context { 1675 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1676 int num; 1677 struct rcu_head rcu; 1678 }; 1679 1680 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout; 1681 void tcp_fastopen_active_disable(struct sock *sk); 1682 bool tcp_fastopen_active_should_disable(struct sock *sk); 1683 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1684 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1685 1686 /* Caller needs to wrap with rcu_read_(un)lock() */ 1687 static inline 1688 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1689 { 1690 struct tcp_fastopen_context *ctx; 1691 1692 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1693 if (!ctx) 1694 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1695 return ctx; 1696 } 1697 1698 static inline 1699 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1700 const struct tcp_fastopen_cookie *orig) 1701 { 1702 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1703 orig->len == foc->len && 1704 !memcmp(orig->val, foc->val, foc->len)) 1705 return true; 1706 return false; 1707 } 1708 1709 static inline 1710 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1711 { 1712 return ctx->num; 1713 } 1714 1715 /* Latencies incurred by various limits for a sender. They are 1716 * chronograph-like stats that are mutually exclusive. 1717 */ 1718 enum tcp_chrono { 1719 TCP_CHRONO_UNSPEC, 1720 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1721 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1722 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1723 __TCP_CHRONO_MAX, 1724 }; 1725 1726 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1727 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1728 1729 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1730 * the same memory storage than skb->destructor/_skb_refdst 1731 */ 1732 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1733 { 1734 skb->destructor = NULL; 1735 skb->_skb_refdst = 0UL; 1736 } 1737 1738 #define tcp_skb_tsorted_save(skb) { \ 1739 unsigned long _save = skb->_skb_refdst; \ 1740 skb->_skb_refdst = 0UL; 1741 1742 #define tcp_skb_tsorted_restore(skb) \ 1743 skb->_skb_refdst = _save; \ 1744 } 1745 1746 void tcp_write_queue_purge(struct sock *sk); 1747 1748 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1749 { 1750 return skb_rb_first(&sk->tcp_rtx_queue); 1751 } 1752 1753 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1754 { 1755 return skb_rb_last(&sk->tcp_rtx_queue); 1756 } 1757 1758 static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) 1759 { 1760 return skb_peek(&sk->sk_write_queue); 1761 } 1762 1763 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1764 { 1765 return skb_peek_tail(&sk->sk_write_queue); 1766 } 1767 1768 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1769 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1770 1771 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1772 { 1773 return skb_peek(&sk->sk_write_queue); 1774 } 1775 1776 static inline bool tcp_skb_is_last(const struct sock *sk, 1777 const struct sk_buff *skb) 1778 { 1779 return skb_queue_is_last(&sk->sk_write_queue, skb); 1780 } 1781 1782 /** 1783 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1784 * @sk: socket 1785 * 1786 * Since the write queue can have a temporary empty skb in it, 1787 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1788 */ 1789 static inline bool tcp_write_queue_empty(const struct sock *sk) 1790 { 1791 const struct tcp_sock *tp = tcp_sk(sk); 1792 1793 return tp->write_seq == tp->snd_nxt; 1794 } 1795 1796 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1797 { 1798 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1799 } 1800 1801 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1802 { 1803 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1804 } 1805 1806 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1807 { 1808 __skb_queue_tail(&sk->sk_write_queue, skb); 1809 1810 /* Queue it, remembering where we must start sending. */ 1811 if (sk->sk_write_queue.next == skb) 1812 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1813 } 1814 1815 /* Insert new before skb on the write queue of sk. */ 1816 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1817 struct sk_buff *skb, 1818 struct sock *sk) 1819 { 1820 __skb_queue_before(&sk->sk_write_queue, skb, new); 1821 } 1822 1823 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1824 { 1825 tcp_skb_tsorted_anchor_cleanup(skb); 1826 __skb_unlink(skb, &sk->sk_write_queue); 1827 } 1828 1829 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1830 1831 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1832 { 1833 tcp_skb_tsorted_anchor_cleanup(skb); 1834 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1835 } 1836 1837 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1838 { 1839 list_del(&skb->tcp_tsorted_anchor); 1840 tcp_rtx_queue_unlink(skb, sk); 1841 sk_wmem_free_skb(sk, skb); 1842 } 1843 1844 static inline void tcp_push_pending_frames(struct sock *sk) 1845 { 1846 if (tcp_send_head(sk)) { 1847 struct tcp_sock *tp = tcp_sk(sk); 1848 1849 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1850 } 1851 } 1852 1853 /* Start sequence of the skb just after the highest skb with SACKed 1854 * bit, valid only if sacked_out > 0 or when the caller has ensured 1855 * validity by itself. 1856 */ 1857 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1858 { 1859 if (!tp->sacked_out) 1860 return tp->snd_una; 1861 1862 if (tp->highest_sack == NULL) 1863 return tp->snd_nxt; 1864 1865 return TCP_SKB_CB(tp->highest_sack)->seq; 1866 } 1867 1868 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1869 { 1870 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 1871 } 1872 1873 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1874 { 1875 return tcp_sk(sk)->highest_sack; 1876 } 1877 1878 static inline void tcp_highest_sack_reset(struct sock *sk) 1879 { 1880 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 1881 } 1882 1883 /* Called when old skb is about to be deleted and replaced by new skb */ 1884 static inline void tcp_highest_sack_replace(struct sock *sk, 1885 struct sk_buff *old, 1886 struct sk_buff *new) 1887 { 1888 if (old == tcp_highest_sack(sk)) 1889 tcp_sk(sk)->highest_sack = new; 1890 } 1891 1892 /* This helper checks if socket has IP_TRANSPARENT set */ 1893 static inline bool inet_sk_transparent(const struct sock *sk) 1894 { 1895 switch (sk->sk_state) { 1896 case TCP_TIME_WAIT: 1897 return inet_twsk(sk)->tw_transparent; 1898 case TCP_NEW_SYN_RECV: 1899 return inet_rsk(inet_reqsk(sk))->no_srccheck; 1900 } 1901 return inet_sk(sk)->transparent; 1902 } 1903 1904 /* Determines whether this is a thin stream (which may suffer from 1905 * increased latency). Used to trigger latency-reducing mechanisms. 1906 */ 1907 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 1908 { 1909 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 1910 } 1911 1912 /* /proc */ 1913 enum tcp_seq_states { 1914 TCP_SEQ_STATE_LISTENING, 1915 TCP_SEQ_STATE_ESTABLISHED, 1916 }; 1917 1918 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 1919 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 1920 void tcp_seq_stop(struct seq_file *seq, void *v); 1921 1922 struct tcp_seq_afinfo { 1923 sa_family_t family; 1924 }; 1925 1926 struct tcp_iter_state { 1927 struct seq_net_private p; 1928 enum tcp_seq_states state; 1929 struct sock *syn_wait_sk; 1930 int bucket, offset, sbucket, num; 1931 loff_t last_pos; 1932 }; 1933 1934 extern struct request_sock_ops tcp_request_sock_ops; 1935 extern struct request_sock_ops tcp6_request_sock_ops; 1936 1937 void tcp_v4_destroy_sock(struct sock *sk); 1938 1939 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 1940 netdev_features_t features); 1941 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 1942 int tcp_gro_complete(struct sk_buff *skb); 1943 1944 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 1945 1946 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 1947 { 1948 struct net *net = sock_net((struct sock *)tp); 1949 return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat; 1950 } 1951 1952 /* @wake is one when sk_stream_write_space() calls us. 1953 * This sends EPOLLOUT only if notsent_bytes is half the limit. 1954 * This mimics the strategy used in sock_def_write_space(). 1955 */ 1956 static inline bool tcp_stream_memory_free(const struct sock *sk, int wake) 1957 { 1958 const struct tcp_sock *tp = tcp_sk(sk); 1959 u32 notsent_bytes = READ_ONCE(tp->write_seq) - 1960 READ_ONCE(tp->snd_nxt); 1961 1962 return (notsent_bytes << wake) < tcp_notsent_lowat(tp); 1963 } 1964 1965 #ifdef CONFIG_PROC_FS 1966 int tcp4_proc_init(void); 1967 void tcp4_proc_exit(void); 1968 #endif 1969 1970 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 1971 int tcp_conn_request(struct request_sock_ops *rsk_ops, 1972 const struct tcp_request_sock_ops *af_ops, 1973 struct sock *sk, struct sk_buff *skb); 1974 1975 /* TCP af-specific functions */ 1976 struct tcp_sock_af_ops { 1977 #ifdef CONFIG_TCP_MD5SIG 1978 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 1979 const struct sock *addr_sk); 1980 int (*calc_md5_hash)(char *location, 1981 const struct tcp_md5sig_key *md5, 1982 const struct sock *sk, 1983 const struct sk_buff *skb); 1984 int (*md5_parse)(struct sock *sk, 1985 int optname, 1986 char __user *optval, 1987 int optlen); 1988 #endif 1989 }; 1990 1991 struct tcp_request_sock_ops { 1992 u16 mss_clamp; 1993 #ifdef CONFIG_TCP_MD5SIG 1994 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 1995 const struct sock *addr_sk); 1996 int (*calc_md5_hash) (char *location, 1997 const struct tcp_md5sig_key *md5, 1998 const struct sock *sk, 1999 const struct sk_buff *skb); 2000 #endif 2001 void (*init_req)(struct request_sock *req, 2002 const struct sock *sk_listener, 2003 struct sk_buff *skb); 2004 #ifdef CONFIG_SYN_COOKIES 2005 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2006 __u16 *mss); 2007 #endif 2008 struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl, 2009 const struct request_sock *req); 2010 u32 (*init_seq)(const struct sk_buff *skb); 2011 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2012 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2013 struct flowi *fl, struct request_sock *req, 2014 struct tcp_fastopen_cookie *foc, 2015 enum tcp_synack_type synack_type); 2016 }; 2017 2018 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2019 #if IS_ENABLED(CONFIG_IPV6) 2020 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2021 #endif 2022 2023 #ifdef CONFIG_SYN_COOKIES 2024 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2025 const struct sock *sk, struct sk_buff *skb, 2026 __u16 *mss) 2027 { 2028 tcp_synq_overflow(sk); 2029 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2030 return ops->cookie_init_seq(skb, mss); 2031 } 2032 #else 2033 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2034 const struct sock *sk, struct sk_buff *skb, 2035 __u16 *mss) 2036 { 2037 return 0; 2038 } 2039 #endif 2040 2041 int tcpv4_offload_init(void); 2042 2043 void tcp_v4_init(void); 2044 void tcp_init(void); 2045 2046 /* tcp_recovery.c */ 2047 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2048 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2049 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2050 u32 reo_wnd); 2051 extern void tcp_rack_mark_lost(struct sock *sk); 2052 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2053 u64 xmit_time); 2054 extern void tcp_rack_reo_timeout(struct sock *sk); 2055 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2056 2057 /* At how many usecs into the future should the RTO fire? */ 2058 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2059 { 2060 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2061 u32 rto = inet_csk(sk)->icsk_rto; 2062 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2063 2064 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2065 } 2066 2067 /* 2068 * Save and compile IPv4 options, return a pointer to it 2069 */ 2070 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2071 struct sk_buff *skb) 2072 { 2073 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2074 struct ip_options_rcu *dopt = NULL; 2075 2076 if (opt->optlen) { 2077 int opt_size = sizeof(*dopt) + opt->optlen; 2078 2079 dopt = kmalloc(opt_size, GFP_ATOMIC); 2080 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2081 kfree(dopt); 2082 dopt = NULL; 2083 } 2084 } 2085 return dopt; 2086 } 2087 2088 /* locally generated TCP pure ACKs have skb->truesize == 2 2089 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2090 * This is much faster than dissecting the packet to find out. 2091 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2092 */ 2093 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2094 { 2095 return skb->truesize == 2; 2096 } 2097 2098 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2099 { 2100 skb->truesize = 2; 2101 } 2102 2103 static inline int tcp_inq(struct sock *sk) 2104 { 2105 struct tcp_sock *tp = tcp_sk(sk); 2106 int answ; 2107 2108 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2109 answ = 0; 2110 } else if (sock_flag(sk, SOCK_URGINLINE) || 2111 !tp->urg_data || 2112 before(tp->urg_seq, tp->copied_seq) || 2113 !before(tp->urg_seq, tp->rcv_nxt)) { 2114 2115 answ = tp->rcv_nxt - tp->copied_seq; 2116 2117 /* Subtract 1, if FIN was received */ 2118 if (answ && sock_flag(sk, SOCK_DONE)) 2119 answ--; 2120 } else { 2121 answ = tp->urg_seq - tp->copied_seq; 2122 } 2123 2124 return answ; 2125 } 2126 2127 int tcp_peek_len(struct socket *sock); 2128 2129 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2130 { 2131 u16 segs_in; 2132 2133 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2134 tp->segs_in += segs_in; 2135 if (skb->len > tcp_hdrlen(skb)) 2136 tp->data_segs_in += segs_in; 2137 } 2138 2139 /* 2140 * TCP listen path runs lockless. 2141 * We forced "struct sock" to be const qualified to make sure 2142 * we don't modify one of its field by mistake. 2143 * Here, we increment sk_drops which is an atomic_t, so we can safely 2144 * make sock writable again. 2145 */ 2146 static inline void tcp_listendrop(const struct sock *sk) 2147 { 2148 atomic_inc(&((struct sock *)sk)->sk_drops); 2149 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2150 } 2151 2152 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2153 2154 /* 2155 * Interface for adding Upper Level Protocols over TCP 2156 */ 2157 2158 #define TCP_ULP_NAME_MAX 16 2159 #define TCP_ULP_MAX 128 2160 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2161 2162 struct tcp_ulp_ops { 2163 struct list_head list; 2164 2165 /* initialize ulp */ 2166 int (*init)(struct sock *sk); 2167 /* update ulp */ 2168 void (*update)(struct sock *sk, struct proto *p, 2169 void (*write_space)(struct sock *sk)); 2170 /* cleanup ulp */ 2171 void (*release)(struct sock *sk); 2172 /* diagnostic */ 2173 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2174 size_t (*get_info_size)(const struct sock *sk); 2175 /* clone ulp */ 2176 void (*clone)(const struct request_sock *req, struct sock *newsk, 2177 const gfp_t priority); 2178 2179 char name[TCP_ULP_NAME_MAX]; 2180 struct module *owner; 2181 }; 2182 int tcp_register_ulp(struct tcp_ulp_ops *type); 2183 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2184 int tcp_set_ulp(struct sock *sk, const char *name); 2185 void tcp_get_available_ulp(char *buf, size_t len); 2186 void tcp_cleanup_ulp(struct sock *sk); 2187 void tcp_update_ulp(struct sock *sk, struct proto *p, 2188 void (*write_space)(struct sock *sk)); 2189 2190 #define MODULE_ALIAS_TCP_ULP(name) \ 2191 __MODULE_INFO(alias, alias_userspace, name); \ 2192 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2193 2194 struct sk_msg; 2195 struct sk_psock; 2196 2197 #ifdef CONFIG_BPF_STREAM_PARSER 2198 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 2199 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2200 #else 2201 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2202 { 2203 } 2204 #endif /* CONFIG_BPF_STREAM_PARSER */ 2205 2206 #ifdef CONFIG_NET_SOCK_MSG 2207 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes, 2208 int flags); 2209 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, 2210 struct msghdr *msg, int len, int flags); 2211 #endif /* CONFIG_NET_SOCK_MSG */ 2212 2213 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2214 * is < 0, then the BPF op failed (for example if the loaded BPF 2215 * program does not support the chosen operation or there is no BPF 2216 * program loaded). 2217 */ 2218 #ifdef CONFIG_BPF 2219 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2220 { 2221 struct bpf_sock_ops_kern sock_ops; 2222 int ret; 2223 2224 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2225 if (sk_fullsock(sk)) { 2226 sock_ops.is_fullsock = 1; 2227 sock_owned_by_me(sk); 2228 } 2229 2230 sock_ops.sk = sk; 2231 sock_ops.op = op; 2232 if (nargs > 0) 2233 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2234 2235 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2236 if (ret == 0) 2237 ret = sock_ops.reply; 2238 else 2239 ret = -1; 2240 return ret; 2241 } 2242 2243 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2244 { 2245 u32 args[2] = {arg1, arg2}; 2246 2247 return tcp_call_bpf(sk, op, 2, args); 2248 } 2249 2250 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2251 u32 arg3) 2252 { 2253 u32 args[3] = {arg1, arg2, arg3}; 2254 2255 return tcp_call_bpf(sk, op, 3, args); 2256 } 2257 2258 #else 2259 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2260 { 2261 return -EPERM; 2262 } 2263 2264 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2265 { 2266 return -EPERM; 2267 } 2268 2269 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2270 u32 arg3) 2271 { 2272 return -EPERM; 2273 } 2274 2275 #endif 2276 2277 static inline u32 tcp_timeout_init(struct sock *sk) 2278 { 2279 int timeout; 2280 2281 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2282 2283 if (timeout <= 0) 2284 timeout = TCP_TIMEOUT_INIT; 2285 return timeout; 2286 } 2287 2288 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2289 { 2290 int rwnd; 2291 2292 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2293 2294 if (rwnd < 0) 2295 rwnd = 0; 2296 return rwnd; 2297 } 2298 2299 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2300 { 2301 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2302 } 2303 2304 static inline void tcp_bpf_rtt(struct sock *sk) 2305 { 2306 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2307 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2308 } 2309 2310 #if IS_ENABLED(CONFIG_SMC) 2311 extern struct static_key_false tcp_have_smc; 2312 #endif 2313 2314 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2315 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2316 void (*cad)(struct sock *sk, u32 ack_seq)); 2317 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2318 void clean_acked_data_flush(void); 2319 #endif 2320 2321 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2322 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2323 const struct tcp_sock *tp) 2324 { 2325 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2326 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2327 } 2328 2329 /* Compute Earliest Departure Time for some control packets 2330 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2331 */ 2332 static inline u64 tcp_transmit_time(const struct sock *sk) 2333 { 2334 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2335 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2336 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2337 2338 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2339 } 2340 return 0; 2341 } 2342 2343 #endif /* _TCP_H */ 2344