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, <[email protected]> 13 */ 14 #ifndef _TCP_H 15 #define _TCP_H 16 17 #define FASTRETRANS_DEBUG 1 18 19 #include <linux/list.h> 20 #include <linux/tcp.h> 21 #include <linux/bug.h> 22 #include <linux/slab.h> 23 #include <linux/cache.h> 24 #include <linux/percpu.h> 25 #include <linux/skbuff.h> 26 #include <linux/kref.h> 27 #include <linux/ktime.h> 28 #include <linux/indirect_call_wrapper.h> 29 30 #include <net/inet_connection_sock.h> 31 #include <net/inet_timewait_sock.h> 32 #include <net/inet_hashtables.h> 33 #include <net/checksum.h> 34 #include <net/request_sock.h> 35 #include <net/sock_reuseport.h> 36 #include <net/sock.h> 37 #include <net/snmp.h> 38 #include <net/ip.h> 39 #include <net/tcp_states.h> 40 #include <net/tcp_ao.h> 41 #include <net/inet_ecn.h> 42 #include <net/dst.h> 43 #include <net/mptcp.h> 44 #include <net/xfrm.h> 45 46 #include <linux/seq_file.h> 47 #include <linux/memcontrol.h> 48 #include <linux/bpf-cgroup.h> 49 #include <linux/siphash.h> 50 51 extern struct inet_hashinfo tcp_hashinfo; 52 53 DECLARE_PER_CPU(unsigned int, tcp_orphan_count); 54 int tcp_orphan_count_sum(void); 55 56 DECLARE_PER_CPU(u32, tcp_tw_isn); 57 58 void tcp_time_wait(struct sock *sk, int state, int timeo); 59 60 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) 61 #define MAX_TCP_OPTION_SPACE 40 62 #define TCP_MIN_SND_MSS 48 63 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 64 65 /* 66 * Never offer a window over 32767 without using window scaling. Some 67 * poor stacks do signed 16bit maths! 68 */ 69 #define MAX_TCP_WINDOW 32767U 70 71 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 72 #define TCP_MIN_MSS 88U 73 74 /* The initial MTU to use for probing */ 75 #define TCP_BASE_MSS 1024 76 77 /* probing interval, default to 10 minutes as per RFC4821 */ 78 #define TCP_PROBE_INTERVAL 600 79 80 /* Specify interval when tcp mtu probing will stop */ 81 #define TCP_PROBE_THRESHOLD 8 82 83 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 84 #define TCP_FASTRETRANS_THRESH 3 85 86 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 87 #define TCP_MAX_QUICKACKS 16U 88 89 /* Maximal number of window scale according to RFC1323 */ 90 #define TCP_MAX_WSCALE 14U 91 92 /* urg_data states */ 93 #define TCP_URG_VALID 0x0100 94 #define TCP_URG_NOTYET 0x0200 95 #define TCP_URG_READ 0x0400 96 97 #define TCP_RETR1 3 /* 98 * This is how many retries it does before it 99 * tries to figure out if the gateway is 100 * down. Minimal RFC value is 3; it corresponds 101 * to ~3sec-8min depending on RTO. 102 */ 103 104 #define TCP_RETR2 15 /* 105 * This should take at least 106 * 90 minutes to time out. 107 * RFC1122 says that the limit is 100 sec. 108 * 15 is ~13-30min depending on RTO. 109 */ 110 111 #define TCP_SYN_RETRIES 6 /* This is how many retries are done 112 * when active opening a connection. 113 * RFC1122 says the minimum retry MUST 114 * be at least 180secs. Nevertheless 115 * this value is corresponding to 116 * 63secs of retransmission with the 117 * current initial RTO. 118 */ 119 120 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done 121 * when passive opening a connection. 122 * This is corresponding to 31secs of 123 * retransmission with the current 124 * initial RTO. 125 */ 126 127 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 128 * state, about 60 seconds */ 129 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 130 /* BSD style FIN_WAIT2 deadlock breaker. 131 * It used to be 3min, new value is 60sec, 132 * to combine FIN-WAIT-2 timeout with 133 * TIME-WAIT timer. 134 */ 135 #define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */ 136 137 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 138 static_assert((1 << ATO_BITS) > TCP_DELACK_MAX); 139 140 #if HZ >= 100 141 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 142 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 143 #else 144 #define TCP_DELACK_MIN 4U 145 #define TCP_ATO_MIN 4U 146 #endif 147 #define TCP_RTO_MAX_SEC 120 148 #define TCP_RTO_MAX ((unsigned)(TCP_RTO_MAX_SEC * HZ)) 149 #define TCP_RTO_MIN ((unsigned)(HZ / 5)) 150 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ 151 152 #define TCP_TIMEOUT_MIN_US (2*USEC_PER_MSEC) /* Min TCP timeout in microsecs */ 153 154 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 155 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 156 * used as a fallback RTO for the 157 * initial data transmission if no 158 * valid RTT sample has been acquired, 159 * most likely due to retrans in 3WHS. 160 */ 161 162 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 163 * for local resources. 164 */ 165 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 166 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 167 #define TCP_KEEPALIVE_INTVL (75*HZ) 168 169 #define MAX_TCP_KEEPIDLE 32767 170 #define MAX_TCP_KEEPINTVL 32767 171 #define MAX_TCP_KEEPCNT 127 172 #define MAX_TCP_SYNCNT 127 173 174 /* Ensure that TCP PAWS checks are relaxed after ~2147 seconds 175 * to avoid overflows. This assumes a clock smaller than 1 Mhz. 176 * Default clock is 1 Khz, tcp_usec_ts uses 1 Mhz. 177 */ 178 #define TCP_PAWS_WRAP (INT_MAX / USEC_PER_SEC) 179 180 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 181 * after this time. It should be equal 182 * (or greater than) TCP_TIMEWAIT_LEN 183 * to provide reliability equal to one 184 * provided by timewait state. 185 */ 186 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 187 * timestamps. It must be less than 188 * minimal timewait lifetime. 189 */ 190 /* 191 * TCP option 192 */ 193 194 #define TCPOPT_NOP 1 /* Padding */ 195 #define TCPOPT_EOL 0 /* End of options */ 196 #define TCPOPT_MSS 2 /* Segment size negotiating */ 197 #define TCPOPT_WINDOW 3 /* Window scaling */ 198 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 199 #define TCPOPT_SACK 5 /* SACK Block */ 200 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 201 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 202 #define TCPOPT_AO 29 /* Authentication Option (RFC5925) */ 203 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ 204 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 205 #define TCPOPT_EXP 254 /* Experimental */ 206 /* Magic number to be after the option value for sharing TCP 207 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 208 */ 209 #define TCPOPT_FASTOPEN_MAGIC 0xF989 210 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 211 212 /* 213 * TCP option lengths 214 */ 215 216 #define TCPOLEN_MSS 4 217 #define TCPOLEN_WINDOW 3 218 #define TCPOLEN_SACK_PERM 2 219 #define TCPOLEN_TIMESTAMP 10 220 #define TCPOLEN_MD5SIG 18 221 #define TCPOLEN_FASTOPEN_BASE 2 222 #define TCPOLEN_EXP_FASTOPEN_BASE 4 223 #define TCPOLEN_EXP_SMC_BASE 6 224 225 /* But this is what stacks really send out. */ 226 #define TCPOLEN_TSTAMP_ALIGNED 12 227 #define TCPOLEN_WSCALE_ALIGNED 4 228 #define TCPOLEN_SACKPERM_ALIGNED 4 229 #define TCPOLEN_SACK_BASE 2 230 #define TCPOLEN_SACK_BASE_ALIGNED 4 231 #define TCPOLEN_SACK_PERBLOCK 8 232 #define TCPOLEN_MD5SIG_ALIGNED 20 233 #define TCPOLEN_MSS_ALIGNED 4 234 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 235 236 /* Flags in tp->nonagle */ 237 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 238 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 239 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 240 241 /* TCP thin-stream limits */ 242 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 243 244 /* TCP initial congestion window as per rfc6928 */ 245 #define TCP_INIT_CWND 10 246 247 /* Bit Flags for sysctl_tcp_fastopen */ 248 #define TFO_CLIENT_ENABLE 1 249 #define TFO_SERVER_ENABLE 2 250 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 251 252 /* Accept SYN data w/o any cookie option */ 253 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 254 255 /* Force enable TFO on all listeners, i.e., not requiring the 256 * TCP_FASTOPEN socket option. 257 */ 258 #define TFO_SERVER_WO_SOCKOPT1 0x400 259 260 261 /* sysctl variables for tcp */ 262 extern int sysctl_tcp_max_orphans; 263 extern long sysctl_tcp_mem[3]; 264 265 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 266 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 267 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 268 269 extern atomic_long_t tcp_memory_allocated; 270 DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); 271 272 extern struct percpu_counter tcp_sockets_allocated; 273 extern unsigned long tcp_memory_pressure; 274 275 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 276 static inline bool tcp_under_memory_pressure(const struct sock *sk) 277 { 278 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 279 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 280 return true; 281 282 return READ_ONCE(tcp_memory_pressure); 283 } 284 /* 285 * The next routines deal with comparing 32 bit unsigned ints 286 * and worry about wraparound (automatic with unsigned arithmetic). 287 */ 288 289 static inline bool before(__u32 seq1, __u32 seq2) 290 { 291 return (__s32)(seq1-seq2) < 0; 292 } 293 #define after(seq2, seq1) before(seq1, seq2) 294 295 /* is s2<=s1<=s3 ? */ 296 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 297 { 298 return seq3 - seq2 >= seq1 - seq2; 299 } 300 301 static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb) 302 { 303 sk_wmem_queued_add(sk, -skb->truesize); 304 if (!skb_zcopy_pure(skb)) 305 sk_mem_uncharge(sk, skb->truesize); 306 else 307 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb))); 308 __kfree_skb(skb); 309 } 310 311 void sk_forced_mem_schedule(struct sock *sk, int size); 312 313 bool tcp_check_oom(const struct sock *sk, int shift); 314 315 316 extern struct proto tcp_prot; 317 318 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 319 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 320 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 321 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 322 323 void tcp_tasklet_init(void); 324 325 int tcp_v4_err(struct sk_buff *skb, u32); 326 327 void tcp_shutdown(struct sock *sk, int how); 328 329 int tcp_v4_early_demux(struct sk_buff *skb); 330 int tcp_v4_rcv(struct sk_buff *skb); 331 332 void tcp_remove_empty_skb(struct sock *sk); 333 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 334 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 335 int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, 336 size_t size, struct ubuf_info *uarg); 337 void tcp_splice_eof(struct socket *sock); 338 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 339 int tcp_wmem_schedule(struct sock *sk, int copy); 340 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 341 int size_goal); 342 void tcp_release_cb(struct sock *sk); 343 void tcp_wfree(struct sk_buff *skb); 344 void tcp_write_timer_handler(struct sock *sk); 345 void tcp_delack_timer_handler(struct sock *sk); 346 int tcp_ioctl(struct sock *sk, int cmd, int *karg); 347 enum skb_drop_reason tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 348 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 349 void tcp_rcv_space_adjust(struct sock *sk); 350 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 351 void tcp_twsk_destructor(struct sock *sk); 352 void tcp_twsk_purge(struct list_head *net_exit_list); 353 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 354 struct pipe_inode_info *pipe, size_t len, 355 unsigned int flags); 356 struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp, 357 bool force_schedule); 358 359 static inline void tcp_dec_quickack_mode(struct sock *sk) 360 { 361 struct inet_connection_sock *icsk = inet_csk(sk); 362 363 if (icsk->icsk_ack.quick) { 364 /* How many ACKs S/ACKing new data have we sent? */ 365 const unsigned int pkts = inet_csk_ack_scheduled(sk) ? 1 : 0; 366 367 if (pkts >= icsk->icsk_ack.quick) { 368 icsk->icsk_ack.quick = 0; 369 /* Leaving quickack mode we deflate ATO. */ 370 icsk->icsk_ack.ato = TCP_ATO_MIN; 371 } else 372 icsk->icsk_ack.quick -= pkts; 373 } 374 } 375 376 #define TCP_ECN_OK 1 377 #define TCP_ECN_QUEUE_CWR 2 378 #define TCP_ECN_DEMAND_CWR 4 379 #define TCP_ECN_SEEN 8 380 381 enum tcp_tw_status { 382 TCP_TW_SUCCESS = 0, 383 TCP_TW_RST = 1, 384 TCP_TW_ACK = 2, 385 TCP_TW_SYN = 3 386 }; 387 388 389 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 390 struct sk_buff *skb, 391 const struct tcphdr *th, 392 u32 *tw_isn); 393 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 394 struct request_sock *req, bool fastopen, 395 bool *lost_race); 396 enum skb_drop_reason tcp_child_process(struct sock *parent, struct sock *child, 397 struct sk_buff *skb); 398 void tcp_enter_loss(struct sock *sk); 399 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag); 400 void tcp_clear_retrans(struct tcp_sock *tp); 401 void tcp_update_metrics(struct sock *sk); 402 void tcp_init_metrics(struct sock *sk); 403 void tcp_metrics_init(void); 404 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 405 void __tcp_close(struct sock *sk, long timeout); 406 void tcp_close(struct sock *sk, long timeout); 407 void tcp_init_sock(struct sock *sk); 408 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb); 409 __poll_t tcp_poll(struct file *file, struct socket *sock, 410 struct poll_table_struct *wait); 411 int do_tcp_getsockopt(struct sock *sk, int level, 412 int optname, sockptr_t optval, sockptr_t optlen); 413 int tcp_getsockopt(struct sock *sk, int level, int optname, 414 char __user *optval, int __user *optlen); 415 bool tcp_bpf_bypass_getsockopt(int level, int optname); 416 int do_tcp_setsockopt(struct sock *sk, int level, int optname, 417 sockptr_t optval, unsigned int optlen); 418 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 419 unsigned int optlen); 420 void tcp_reset_keepalive_timer(struct sock *sk, unsigned long timeout); 421 void tcp_set_keepalive(struct sock *sk, int val); 422 void tcp_syn_ack_timeout(const struct request_sock *req); 423 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 424 int flags, int *addr_len); 425 int tcp_set_rcvlowat(struct sock *sk, int val); 426 int tcp_set_window_clamp(struct sock *sk, int val); 427 void tcp_update_recv_tstamps(struct sk_buff *skb, 428 struct scm_timestamping_internal *tss); 429 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, 430 struct scm_timestamping_internal *tss); 431 void tcp_data_ready(struct sock *sk); 432 #ifdef CONFIG_MMU 433 int tcp_mmap(struct file *file, struct socket *sock, 434 struct vm_area_struct *vma); 435 #endif 436 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 437 struct tcp_options_received *opt_rx, 438 int estab, struct tcp_fastopen_cookie *foc); 439 440 /* 441 * BPF SKB-less helpers 442 */ 443 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 444 struct tcphdr *th, u32 *cookie); 445 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 446 struct tcphdr *th, u32 *cookie); 447 u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss); 448 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 449 const struct tcp_request_sock_ops *af_ops, 450 struct sock *sk, struct tcphdr *th); 451 /* 452 * TCP v4 functions exported for the inet6 API 453 */ 454 455 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 456 void tcp_v4_mtu_reduced(struct sock *sk); 457 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 458 void tcp_ld_RTO_revert(struct sock *sk, u32 seq); 459 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 460 struct sock *tcp_create_openreq_child(const struct sock *sk, 461 struct request_sock *req, 462 struct sk_buff *skb); 463 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 464 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 465 struct request_sock *req, 466 struct dst_entry *dst, 467 struct request_sock *req_unhash, 468 bool *own_req); 469 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 470 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 471 int tcp_connect(struct sock *sk); 472 enum tcp_synack_type { 473 TCP_SYNACK_NORMAL, 474 TCP_SYNACK_FASTOPEN, 475 TCP_SYNACK_COOKIE, 476 }; 477 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 478 struct request_sock *req, 479 struct tcp_fastopen_cookie *foc, 480 enum tcp_synack_type synack_type, 481 struct sk_buff *syn_skb); 482 int tcp_disconnect(struct sock *sk, int flags); 483 484 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 485 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 486 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 487 488 /* From syncookies.c */ 489 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 490 struct request_sock *req, 491 struct dst_entry *dst); 492 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th); 493 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 494 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops, 495 struct sock *sk, struct sk_buff *skb, 496 struct tcp_options_received *tcp_opt, 497 int mss, u32 tsoff); 498 499 #if IS_ENABLED(CONFIG_BPF) 500 struct bpf_tcp_req_attrs { 501 u32 rcv_tsval; 502 u32 rcv_tsecr; 503 u16 mss; 504 u8 rcv_wscale; 505 u8 snd_wscale; 506 u8 ecn_ok; 507 u8 wscale_ok; 508 u8 sack_ok; 509 u8 tstamp_ok; 510 u8 usec_ts_ok; 511 u8 reserved[3]; 512 }; 513 #endif 514 515 #ifdef CONFIG_SYN_COOKIES 516 517 /* Syncookies use a monotonic timer which increments every 60 seconds. 518 * This counter is used both as a hash input and partially encoded into 519 * the cookie value. A cookie is only validated further if the delta 520 * between the current counter value and the encoded one is less than this, 521 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 522 * the counter advances immediately after a cookie is generated). 523 */ 524 #define MAX_SYNCOOKIE_AGE 2 525 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 526 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 527 528 /* syncookies: remember time of last synqueue overflow 529 * But do not dirty this field too often (once per second is enough) 530 * It is racy as we do not hold a lock, but race is very minor. 531 */ 532 static inline void tcp_synq_overflow(const struct sock *sk) 533 { 534 unsigned int last_overflow; 535 unsigned int now = jiffies; 536 537 if (sk->sk_reuseport) { 538 struct sock_reuseport *reuse; 539 540 reuse = rcu_dereference(sk->sk_reuseport_cb); 541 if (likely(reuse)) { 542 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 543 if (!time_between32(now, last_overflow, 544 last_overflow + HZ)) 545 WRITE_ONCE(reuse->synq_overflow_ts, now); 546 return; 547 } 548 } 549 550 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 551 if (!time_between32(now, last_overflow, last_overflow + HZ)) 552 WRITE_ONCE(tcp_sk_rw(sk)->rx_opt.ts_recent_stamp, now); 553 } 554 555 /* syncookies: no recent synqueue overflow on this listening socket? */ 556 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 557 { 558 unsigned int last_overflow; 559 unsigned int now = jiffies; 560 561 if (sk->sk_reuseport) { 562 struct sock_reuseport *reuse; 563 564 reuse = rcu_dereference(sk->sk_reuseport_cb); 565 if (likely(reuse)) { 566 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 567 return !time_between32(now, last_overflow - HZ, 568 last_overflow + 569 TCP_SYNCOOKIE_VALID); 570 } 571 } 572 573 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 574 575 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 576 * then we're under synflood. However, we have to use 577 * 'last_overflow - HZ' as lower bound. That's because a concurrent 578 * tcp_synq_overflow() could update .ts_recent_stamp after we read 579 * jiffies but before we store .ts_recent_stamp into last_overflow, 580 * which could lead to rejecting a valid syncookie. 581 */ 582 return !time_between32(now, last_overflow - HZ, 583 last_overflow + TCP_SYNCOOKIE_VALID); 584 } 585 586 static inline u32 tcp_cookie_time(void) 587 { 588 u64 val = get_jiffies_64(); 589 590 do_div(val, TCP_SYNCOOKIE_PERIOD); 591 return val; 592 } 593 594 /* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */ 595 static inline u64 tcp_ns_to_ts(bool usec_ts, u64 val) 596 { 597 if (usec_ts) 598 return div_u64(val, NSEC_PER_USEC); 599 600 return div_u64(val, NSEC_PER_MSEC); 601 } 602 603 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 604 u16 *mssp); 605 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 606 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 607 bool cookie_timestamp_decode(const struct net *net, 608 struct tcp_options_received *opt); 609 610 static inline bool cookie_ecn_ok(const struct net *net, const struct dst_entry *dst) 611 { 612 return READ_ONCE(net->ipv4.sysctl_tcp_ecn) || 613 dst_feature(dst, RTAX_FEATURE_ECN); 614 } 615 616 #if IS_ENABLED(CONFIG_BPF) 617 static inline bool cookie_bpf_ok(struct sk_buff *skb) 618 { 619 return skb->sk; 620 } 621 622 struct request_sock *cookie_bpf_check(struct sock *sk, struct sk_buff *skb); 623 #else 624 static inline bool cookie_bpf_ok(struct sk_buff *skb) 625 { 626 return false; 627 } 628 629 static inline struct request_sock *cookie_bpf_check(struct net *net, struct sock *sk, 630 struct sk_buff *skb) 631 { 632 return NULL; 633 } 634 #endif 635 636 /* From net/ipv6/syncookies.c */ 637 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th); 638 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 639 640 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 641 const struct tcphdr *th, u16 *mssp); 642 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 643 #endif 644 /* tcp_output.c */ 645 646 void tcp_skb_entail(struct sock *sk, struct sk_buff *skb); 647 void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb); 648 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 649 int nonagle); 650 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 651 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 652 void tcp_retransmit_timer(struct sock *sk); 653 void tcp_xmit_retransmit_queue(struct sock *); 654 void tcp_simple_retransmit(struct sock *); 655 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 656 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 657 enum tcp_queue { 658 TCP_FRAG_IN_WRITE_QUEUE, 659 TCP_FRAG_IN_RTX_QUEUE, 660 }; 661 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 662 struct sk_buff *skb, u32 len, 663 unsigned int mss_now, gfp_t gfp); 664 665 void tcp_send_probe0(struct sock *); 666 int tcp_write_wakeup(struct sock *, int mib); 667 void tcp_send_fin(struct sock *sk); 668 void tcp_send_active_reset(struct sock *sk, gfp_t priority, 669 enum sk_rst_reason reason); 670 int tcp_send_synack(struct sock *); 671 void tcp_push_one(struct sock *, unsigned int mss_now); 672 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 673 void tcp_send_ack(struct sock *sk); 674 void tcp_send_delayed_ack(struct sock *sk); 675 void tcp_send_loss_probe(struct sock *sk); 676 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 677 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 678 const struct sk_buff *next_skb); 679 680 /* tcp_input.c */ 681 void tcp_rearm_rto(struct sock *sk); 682 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 683 void tcp_done_with_error(struct sock *sk, int err); 684 void tcp_reset(struct sock *sk, struct sk_buff *skb); 685 void tcp_fin(struct sock *sk); 686 void tcp_check_space(struct sock *sk); 687 void tcp_sack_compress_send_ack(struct sock *sk); 688 689 static inline void tcp_cleanup_skb(struct sk_buff *skb) 690 { 691 skb_dst_drop(skb); 692 secpath_reset(skb); 693 } 694 695 static inline void tcp_add_receive_queue(struct sock *sk, struct sk_buff *skb) 696 { 697 DEBUG_NET_WARN_ON_ONCE(skb_dst(skb)); 698 DEBUG_NET_WARN_ON_ONCE(secpath_exists(skb)); 699 __skb_queue_tail(&sk->sk_receive_queue, skb); 700 } 701 702 /* tcp_timer.c */ 703 void tcp_init_xmit_timers(struct sock *); 704 static inline void tcp_clear_xmit_timers(struct sock *sk) 705 { 706 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 707 __sock_put(sk); 708 709 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 710 __sock_put(sk); 711 712 inet_csk_clear_xmit_timers(sk); 713 } 714 715 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 716 unsigned int tcp_current_mss(struct sock *sk); 717 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 718 719 /* Bound MSS / TSO packet size with the half of the window */ 720 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 721 { 722 int cutoff; 723 724 /* When peer uses tiny windows, there is no use in packetizing 725 * to sub-MSS pieces for the sake of SWS or making sure there 726 * are enough packets in the pipe for fast recovery. 727 * 728 * On the other hand, for extremely large MSS devices, handling 729 * smaller than MSS windows in this way does make sense. 730 */ 731 if (tp->max_window > TCP_MSS_DEFAULT) 732 cutoff = (tp->max_window >> 1); 733 else 734 cutoff = tp->max_window; 735 736 if (cutoff && pktsize > cutoff) 737 return max_t(int, cutoff, 68U - tp->tcp_header_len); 738 else 739 return pktsize; 740 } 741 742 /* tcp.c */ 743 void tcp_get_info(struct sock *, struct tcp_info *); 744 745 /* Read 'sendfile()'-style from a TCP socket */ 746 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 747 sk_read_actor_t recv_actor); 748 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 749 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off); 750 void tcp_read_done(struct sock *sk, size_t len); 751 752 void tcp_initialize_rcv_mss(struct sock *sk); 753 754 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 755 int tcp_mss_to_mtu(struct sock *sk, int mss); 756 void tcp_mtup_init(struct sock *sk); 757 758 static inline unsigned int tcp_rto_max(const struct sock *sk) 759 { 760 return READ_ONCE(inet_csk(sk)->icsk_rto_max); 761 } 762 763 static inline void tcp_bound_rto(struct sock *sk) 764 { 765 inet_csk(sk)->icsk_rto = min(inet_csk(sk)->icsk_rto, tcp_rto_max(sk)); 766 } 767 768 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 769 { 770 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 771 } 772 773 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 774 { 775 /* mptcp hooks are only on the slow path */ 776 if (sk_is_mptcp((struct sock *)tp)) 777 return; 778 779 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 780 ntohl(TCP_FLAG_ACK) | 781 snd_wnd); 782 } 783 784 static inline void tcp_fast_path_on(struct tcp_sock *tp) 785 { 786 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 787 } 788 789 static inline void tcp_fast_path_check(struct sock *sk) 790 { 791 struct tcp_sock *tp = tcp_sk(sk); 792 793 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 794 tp->rcv_wnd && 795 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 796 !tp->urg_data) 797 tcp_fast_path_on(tp); 798 } 799 800 u32 tcp_delack_max(const struct sock *sk); 801 802 /* Compute the actual rto_min value */ 803 static inline u32 tcp_rto_min(const struct sock *sk) 804 { 805 const struct dst_entry *dst = __sk_dst_get(sk); 806 u32 rto_min = inet_csk(sk)->icsk_rto_min; 807 808 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 809 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 810 return rto_min; 811 } 812 813 static inline u32 tcp_rto_min_us(const struct sock *sk) 814 { 815 return jiffies_to_usecs(tcp_rto_min(sk)); 816 } 817 818 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 819 { 820 return dst_metric_locked(dst, RTAX_CC_ALGO); 821 } 822 823 /* Minimum RTT in usec. ~0 means not available. */ 824 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 825 { 826 return minmax_get(&tp->rtt_min); 827 } 828 829 /* Compute the actual receive window we are currently advertising. 830 * Rcv_nxt can be after the window if our peer push more data 831 * than the offered window. 832 */ 833 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 834 { 835 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 836 837 if (win < 0) 838 win = 0; 839 return (u32) win; 840 } 841 842 /* Choose a new window, without checks for shrinking, and without 843 * scaling applied to the result. The caller does these things 844 * if necessary. This is a "raw" window selection. 845 */ 846 u32 __tcp_select_window(struct sock *sk); 847 848 void tcp_send_window_probe(struct sock *sk); 849 850 /* TCP uses 32bit jiffies to save some space. 851 * Note that this is different from tcp_time_stamp, which 852 * historically has been the same until linux-4.13. 853 */ 854 #define tcp_jiffies32 ((u32)jiffies) 855 856 /* 857 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 858 * It is no longer tied to jiffies, but to 1 ms clock. 859 * Note: double check if you want to use tcp_jiffies32 instead of this. 860 */ 861 #define TCP_TS_HZ 1000 862 863 static inline u64 tcp_clock_ns(void) 864 { 865 return ktime_get_ns(); 866 } 867 868 static inline u64 tcp_clock_us(void) 869 { 870 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 871 } 872 873 static inline u64 tcp_clock_ms(void) 874 { 875 return div_u64(tcp_clock_ns(), NSEC_PER_MSEC); 876 } 877 878 /* TCP Timestamp included in TS option (RFC 1323) can either use ms 879 * or usec resolution. Each socket carries a flag to select one or other 880 * resolution, as the route attribute could change anytime. 881 * Each flow must stick to initial resolution. 882 */ 883 static inline u32 tcp_clock_ts(bool usec_ts) 884 { 885 return usec_ts ? tcp_clock_us() : tcp_clock_ms(); 886 } 887 888 static inline u32 tcp_time_stamp_ms(const struct tcp_sock *tp) 889 { 890 return div_u64(tp->tcp_mstamp, USEC_PER_MSEC); 891 } 892 893 static inline u32 tcp_time_stamp_ts(const struct tcp_sock *tp) 894 { 895 if (tp->tcp_usec_ts) 896 return tp->tcp_mstamp; 897 return tcp_time_stamp_ms(tp); 898 } 899 900 void tcp_mstamp_refresh(struct tcp_sock *tp); 901 902 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 903 { 904 return max_t(s64, t1 - t0, 0); 905 } 906 907 /* provide the departure time in us unit */ 908 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 909 { 910 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 911 } 912 913 /* Provide skb TSval in usec or ms unit */ 914 static inline u32 tcp_skb_timestamp_ts(bool usec_ts, const struct sk_buff *skb) 915 { 916 if (usec_ts) 917 return tcp_skb_timestamp_us(skb); 918 919 return div_u64(skb->skb_mstamp_ns, NSEC_PER_MSEC); 920 } 921 922 static inline u32 tcp_tw_tsval(const struct tcp_timewait_sock *tcptw) 923 { 924 return tcp_clock_ts(tcptw->tw_sk.tw_usec_ts) + tcptw->tw_ts_offset; 925 } 926 927 static inline u32 tcp_rsk_tsval(const struct tcp_request_sock *treq) 928 { 929 return tcp_clock_ts(treq->req_usec_ts) + treq->ts_off; 930 } 931 932 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 933 934 #define TCPHDR_FIN 0x01 935 #define TCPHDR_SYN 0x02 936 #define TCPHDR_RST 0x04 937 #define TCPHDR_PSH 0x08 938 #define TCPHDR_ACK 0x10 939 #define TCPHDR_URG 0x20 940 #define TCPHDR_ECE 0x40 941 #define TCPHDR_CWR 0x80 942 943 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 944 945 /* State flags for sacked in struct tcp_skb_cb */ 946 enum tcp_skb_cb_sacked_flags { 947 TCPCB_SACKED_ACKED = (1 << 0), /* SKB ACK'd by a SACK block */ 948 TCPCB_SACKED_RETRANS = (1 << 1), /* SKB retransmitted */ 949 TCPCB_LOST = (1 << 2), /* SKB is lost */ 950 TCPCB_TAGBITS = (TCPCB_SACKED_ACKED | TCPCB_SACKED_RETRANS | 951 TCPCB_LOST), /* All tag bits */ 952 TCPCB_REPAIRED = (1 << 4), /* SKB repaired (no skb_mstamp_ns) */ 953 TCPCB_EVER_RETRANS = (1 << 7), /* Ever retransmitted frame */ 954 TCPCB_RETRANS = (TCPCB_SACKED_RETRANS | TCPCB_EVER_RETRANS | 955 TCPCB_REPAIRED), 956 }; 957 958 /* This is what the send packet queuing engine uses to pass 959 * TCP per-packet control information to the transmission code. 960 * We also store the host-order sequence numbers in here too. 961 * This is 44 bytes if IPV6 is enabled. 962 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 963 */ 964 struct tcp_skb_cb { 965 __u32 seq; /* Starting sequence number */ 966 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 967 union { 968 /* Note : 969 * tcp_gso_segs/size are used in write queue only, 970 * cf tcp_skb_pcount()/tcp_skb_mss() 971 */ 972 struct { 973 u16 tcp_gso_segs; 974 u16 tcp_gso_size; 975 }; 976 }; 977 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 978 979 __u8 sacked; /* State flags for SACK. */ 980 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 981 #define TSTAMP_ACK_SK 0x1 982 #define TSTAMP_ACK_BPF 0x2 983 __u8 txstamp_ack:2, /* Record TX timestamp for ack? */ 984 eor:1, /* Is skb MSG_EOR marked? */ 985 has_rxtstamp:1, /* SKB has a RX timestamp */ 986 unused:4; 987 __u32 ack_seq; /* Sequence number ACK'd */ 988 union { 989 struct { 990 #define TCPCB_DELIVERED_CE_MASK ((1U<<20) - 1) 991 /* There is space for up to 24 bytes */ 992 __u32 is_app_limited:1, /* cwnd not fully used? */ 993 delivered_ce:20, 994 unused:11; 995 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 996 __u32 delivered; 997 /* start of send pipeline phase */ 998 u64 first_tx_mstamp; 999 /* when we reached the "delivered" count */ 1000 u64 delivered_mstamp; 1001 } tx; /* only used for outgoing skbs */ 1002 union { 1003 struct inet_skb_parm h4; 1004 #if IS_ENABLED(CONFIG_IPV6) 1005 struct inet6_skb_parm h6; 1006 #endif 1007 } header; /* For incoming skbs */ 1008 }; 1009 }; 1010 1011 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 1012 1013 extern const struct inet_connection_sock_af_ops ipv4_specific; 1014 1015 #if IS_ENABLED(CONFIG_IPV6) 1016 /* This is the variant of inet6_iif() that must be used by TCP, 1017 * as TCP moves IP6CB into a different location in skb->cb[] 1018 */ 1019 static inline int tcp_v6_iif(const struct sk_buff *skb) 1020 { 1021 return TCP_SKB_CB(skb)->header.h6.iif; 1022 } 1023 1024 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 1025 { 1026 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 1027 1028 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 1029 } 1030 1031 /* TCP_SKB_CB reference means this can not be used from early demux */ 1032 static inline int tcp_v6_sdif(const struct sk_buff *skb) 1033 { 1034 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 1035 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 1036 return TCP_SKB_CB(skb)->header.h6.iif; 1037 #endif 1038 return 0; 1039 } 1040 1041 extern const struct inet_connection_sock_af_ops ipv6_specific; 1042 1043 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 1044 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 1045 void tcp_v6_early_demux(struct sk_buff *skb); 1046 1047 #endif 1048 1049 /* TCP_SKB_CB reference means this can not be used from early demux */ 1050 static inline int tcp_v4_sdif(struct sk_buff *skb) 1051 { 1052 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 1053 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 1054 return TCP_SKB_CB(skb)->header.h4.iif; 1055 #endif 1056 return 0; 1057 } 1058 1059 /* Due to TSO, an SKB can be composed of multiple actual 1060 * packets. To keep these tracked properly, we use this. 1061 */ 1062 static inline int tcp_skb_pcount(const struct sk_buff *skb) 1063 { 1064 return TCP_SKB_CB(skb)->tcp_gso_segs; 1065 } 1066 1067 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 1068 { 1069 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 1070 } 1071 1072 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 1073 { 1074 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 1075 } 1076 1077 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 1078 static inline int tcp_skb_mss(const struct sk_buff *skb) 1079 { 1080 return TCP_SKB_CB(skb)->tcp_gso_size; 1081 } 1082 1083 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 1084 { 1085 return likely(!TCP_SKB_CB(skb)->eor); 1086 } 1087 1088 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 1089 const struct sk_buff *from) 1090 { 1091 /* skb_cmp_decrypted() not needed, use tcp_write_collapse_fence() */ 1092 return likely(tcp_skb_can_collapse_to(to) && 1093 mptcp_skb_can_collapse(to, from) && 1094 skb_pure_zcopy_same(to, from) && 1095 skb_frags_readable(to) == skb_frags_readable(from)); 1096 } 1097 1098 static inline bool tcp_skb_can_collapse_rx(const struct sk_buff *to, 1099 const struct sk_buff *from) 1100 { 1101 return likely(mptcp_skb_can_collapse(to, from) && 1102 !skb_cmp_decrypted(to, from)); 1103 } 1104 1105 /* Events passed to congestion control interface */ 1106 enum tcp_ca_event { 1107 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 1108 CA_EVENT_CWND_RESTART, /* congestion window restart */ 1109 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 1110 CA_EVENT_LOSS, /* loss timeout */ 1111 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 1112 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 1113 }; 1114 1115 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1116 enum tcp_ca_ack_event_flags { 1117 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1118 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1119 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1120 }; 1121 1122 /* 1123 * Interface for adding new TCP congestion control handlers 1124 */ 1125 #define TCP_CA_NAME_MAX 16 1126 #define TCP_CA_MAX 128 1127 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1128 1129 #define TCP_CA_UNSPEC 0 1130 1131 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1132 #define TCP_CONG_NON_RESTRICTED 0x1 1133 /* Requires ECN/ECT set on all packets */ 1134 #define TCP_CONG_NEEDS_ECN 0x2 1135 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1136 1137 union tcp_cc_info; 1138 1139 struct ack_sample { 1140 u32 pkts_acked; 1141 s32 rtt_us; 1142 u32 in_flight; 1143 }; 1144 1145 /* A rate sample measures the number of (original/retransmitted) data 1146 * packets delivered "delivered" over an interval of time "interval_us". 1147 * The tcp_rate.c code fills in the rate sample, and congestion 1148 * control modules that define a cong_control function to run at the end 1149 * of ACK processing can optionally chose to consult this sample when 1150 * setting cwnd and pacing rate. 1151 * A sample is invalid if "delivered" or "interval_us" is negative. 1152 */ 1153 struct rate_sample { 1154 u64 prior_mstamp; /* starting timestamp for interval */ 1155 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1156 u32 prior_delivered_ce;/* tp->delivered_ce at "prior_mstamp" */ 1157 s32 delivered; /* number of packets delivered over interval */ 1158 s32 delivered_ce; /* number of packets delivered w/ CE marks*/ 1159 long interval_us; /* time for tp->delivered to incr "delivered" */ 1160 u32 snd_interval_us; /* snd interval for delivered packets */ 1161 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1162 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1163 int losses; /* number of packets marked lost upon ACK */ 1164 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1165 u32 prior_in_flight; /* in flight before this ACK */ 1166 u32 last_end_seq; /* end_seq of most recently ACKed packet */ 1167 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1168 bool is_retrans; /* is sample from retransmission? */ 1169 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1170 }; 1171 1172 struct tcp_congestion_ops { 1173 /* fast path fields are put first to fill one cache line */ 1174 1175 /* return slow start threshold (required) */ 1176 u32 (*ssthresh)(struct sock *sk); 1177 1178 /* do new cwnd calculation (required) */ 1179 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1180 1181 /* call before changing ca_state (optional) */ 1182 void (*set_state)(struct sock *sk, u8 new_state); 1183 1184 /* call when cwnd event occurs (optional) */ 1185 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1186 1187 /* call when ack arrives (optional) */ 1188 void (*in_ack_event)(struct sock *sk, u32 flags); 1189 1190 /* hook for packet ack accounting (optional) */ 1191 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1192 1193 /* override sysctl_tcp_min_tso_segs */ 1194 u32 (*min_tso_segs)(struct sock *sk); 1195 1196 /* call when packets are delivered to update cwnd and pacing rate, 1197 * after all the ca_state processing. (optional) 1198 */ 1199 void (*cong_control)(struct sock *sk, u32 ack, int flag, const struct rate_sample *rs); 1200 1201 1202 /* new value of cwnd after loss (required) */ 1203 u32 (*undo_cwnd)(struct sock *sk); 1204 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1205 u32 (*sndbuf_expand)(struct sock *sk); 1206 1207 /* control/slow paths put last */ 1208 /* get info for inet_diag (optional) */ 1209 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1210 union tcp_cc_info *info); 1211 1212 char name[TCP_CA_NAME_MAX]; 1213 struct module *owner; 1214 struct list_head list; 1215 u32 key; 1216 u32 flags; 1217 1218 /* initialize private data (optional) */ 1219 void (*init)(struct sock *sk); 1220 /* cleanup private data (optional) */ 1221 void (*release)(struct sock *sk); 1222 } ____cacheline_aligned_in_smp; 1223 1224 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1225 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1226 int tcp_update_congestion_control(struct tcp_congestion_ops *type, 1227 struct tcp_congestion_ops *old_type); 1228 int tcp_validate_congestion_control(struct tcp_congestion_ops *ca); 1229 1230 void tcp_assign_congestion_control(struct sock *sk); 1231 void tcp_init_congestion_control(struct sock *sk); 1232 void tcp_cleanup_congestion_control(struct sock *sk); 1233 int tcp_set_default_congestion_control(struct net *net, const char *name); 1234 void tcp_get_default_congestion_control(struct net *net, char *name); 1235 void tcp_get_available_congestion_control(char *buf, size_t len); 1236 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1237 int tcp_set_allowed_congestion_control(char *allowed); 1238 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1239 bool cap_net_admin); 1240 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1241 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1242 1243 u32 tcp_reno_ssthresh(struct sock *sk); 1244 u32 tcp_reno_undo_cwnd(struct sock *sk); 1245 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1246 extern struct tcp_congestion_ops tcp_reno; 1247 1248 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1249 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1250 u32 tcp_ca_get_key_by_name(const char *name, bool *ecn_ca); 1251 #ifdef CONFIG_INET 1252 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1253 #else 1254 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1255 { 1256 return NULL; 1257 } 1258 #endif 1259 1260 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1261 { 1262 const struct inet_connection_sock *icsk = inet_csk(sk); 1263 1264 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1265 } 1266 1267 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1268 { 1269 const struct inet_connection_sock *icsk = inet_csk(sk); 1270 1271 if (icsk->icsk_ca_ops->cwnd_event) 1272 icsk->icsk_ca_ops->cwnd_event(sk, event); 1273 } 1274 1275 /* From tcp_cong.c */ 1276 void tcp_set_ca_state(struct sock *sk, const u8 ca_state); 1277 1278 /* From tcp_rate.c */ 1279 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1280 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1281 struct rate_sample *rs); 1282 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1283 bool is_sack_reneg, struct rate_sample *rs); 1284 void tcp_rate_check_app_limited(struct sock *sk); 1285 1286 static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2) 1287 { 1288 return t1 > t2 || (t1 == t2 && after(seq1, seq2)); 1289 } 1290 1291 /* These functions determine how the current flow behaves in respect of SACK 1292 * handling. SACK is negotiated with the peer, and therefore it can vary 1293 * between different flows. 1294 * 1295 * tcp_is_sack - SACK enabled 1296 * tcp_is_reno - No SACK 1297 */ 1298 static inline int tcp_is_sack(const struct tcp_sock *tp) 1299 { 1300 return likely(tp->rx_opt.sack_ok); 1301 } 1302 1303 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1304 { 1305 return !tcp_is_sack(tp); 1306 } 1307 1308 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1309 { 1310 return tp->sacked_out + tp->lost_out; 1311 } 1312 1313 /* This determines how many packets are "in the network" to the best 1314 * of our knowledge. In many cases it is conservative, but where 1315 * detailed information is available from the receiver (via SACK 1316 * blocks etc.) we can make more aggressive calculations. 1317 * 1318 * Use this for decisions involving congestion control, use just 1319 * tp->packets_out to determine if the send queue is empty or not. 1320 * 1321 * Read this equation as: 1322 * 1323 * "Packets sent once on transmission queue" MINUS 1324 * "Packets left network, but not honestly ACKed yet" PLUS 1325 * "Packets fast retransmitted" 1326 */ 1327 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1328 { 1329 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1330 } 1331 1332 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1333 1334 static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp) 1335 { 1336 return tp->snd_cwnd; 1337 } 1338 1339 static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val) 1340 { 1341 WARN_ON_ONCE((int)val <= 0); 1342 tp->snd_cwnd = val; 1343 } 1344 1345 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1346 { 1347 return tcp_snd_cwnd(tp) < tp->snd_ssthresh; 1348 } 1349 1350 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1351 { 1352 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1353 } 1354 1355 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1356 { 1357 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1358 (1 << inet_csk(sk)->icsk_ca_state); 1359 } 1360 1361 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1362 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1363 * ssthresh. 1364 */ 1365 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1366 { 1367 const struct tcp_sock *tp = tcp_sk(sk); 1368 1369 if (tcp_in_cwnd_reduction(sk)) 1370 return tp->snd_ssthresh; 1371 else 1372 return max(tp->snd_ssthresh, 1373 ((tcp_snd_cwnd(tp) >> 1) + 1374 (tcp_snd_cwnd(tp) >> 2))); 1375 } 1376 1377 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1378 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1379 1380 void tcp_enter_cwr(struct sock *sk); 1381 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1382 1383 /* The maximum number of MSS of available cwnd for which TSO defers 1384 * sending if not using sysctl_tcp_tso_win_divisor. 1385 */ 1386 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1387 { 1388 return 3; 1389 } 1390 1391 /* Returns end sequence number of the receiver's advertised window */ 1392 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1393 { 1394 return tp->snd_una + tp->snd_wnd; 1395 } 1396 1397 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1398 * flexible approach. The RFC suggests cwnd should not be raised unless 1399 * it was fully used previously. And that's exactly what we do in 1400 * congestion avoidance mode. But in slow start we allow cwnd to grow 1401 * as long as the application has used half the cwnd. 1402 * Example : 1403 * cwnd is 10 (IW10), but application sends 9 frames. 1404 * We allow cwnd to reach 18 when all frames are ACKed. 1405 * This check is safe because it's as aggressive as slow start which already 1406 * risks 100% overshoot. The advantage is that we discourage application to 1407 * either send more filler packets or data to artificially blow up the cwnd 1408 * usage, and allow application-limited process to probe bw more aggressively. 1409 */ 1410 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1411 { 1412 const struct tcp_sock *tp = tcp_sk(sk); 1413 1414 if (tp->is_cwnd_limited) 1415 return true; 1416 1417 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1418 if (tcp_in_slow_start(tp)) 1419 return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out; 1420 1421 return false; 1422 } 1423 1424 /* BBR congestion control needs pacing. 1425 * Same remark for SO_MAX_PACING_RATE. 1426 * sch_fq packet scheduler is efficiently handling pacing, 1427 * but is not always installed/used. 1428 * Return true if TCP stack should pace packets itself. 1429 */ 1430 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1431 { 1432 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1433 } 1434 1435 /* Estimates in how many jiffies next packet for this flow can be sent. 1436 * Scheduling a retransmit timer too early would be silly. 1437 */ 1438 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1439 { 1440 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1441 1442 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1443 } 1444 1445 static inline void tcp_reset_xmit_timer(struct sock *sk, 1446 const int what, 1447 unsigned long when, 1448 bool pace_delay) 1449 { 1450 if (pace_delay) 1451 when += tcp_pacing_delay(sk); 1452 inet_csk_reset_xmit_timer(sk, what, when, 1453 tcp_rto_max(sk)); 1454 } 1455 1456 /* Something is really bad, we could not queue an additional packet, 1457 * because qdisc is full or receiver sent a 0 window, or we are paced. 1458 * We do not want to add fuel to the fire, or abort too early, 1459 * so make sure the timer we arm now is at least 200ms in the future, 1460 * regardless of current icsk_rto value (as it could be ~2ms) 1461 */ 1462 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1463 { 1464 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1465 } 1466 1467 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1468 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1469 unsigned long max_when) 1470 { 1471 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1472 inet_csk(sk)->icsk_backoff); 1473 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1474 1475 return (unsigned long)min_t(u64, when, max_when); 1476 } 1477 1478 static inline void tcp_check_probe_timer(struct sock *sk) 1479 { 1480 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1481 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1482 tcp_probe0_base(sk), true); 1483 } 1484 1485 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1486 { 1487 tp->snd_wl1 = seq; 1488 } 1489 1490 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1491 { 1492 tp->snd_wl1 = seq; 1493 } 1494 1495 /* 1496 * Calculate(/check) TCP checksum 1497 */ 1498 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1499 __be32 daddr, __wsum base) 1500 { 1501 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1502 } 1503 1504 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1505 { 1506 return !skb_csum_unnecessary(skb) && 1507 __skb_checksum_complete(skb); 1508 } 1509 1510 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1511 enum skb_drop_reason *reason); 1512 1513 1514 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1515 void tcp_set_state(struct sock *sk, int state); 1516 void tcp_done(struct sock *sk); 1517 int tcp_abort(struct sock *sk, int err); 1518 1519 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1520 { 1521 rx_opt->dsack = 0; 1522 rx_opt->num_sacks = 0; 1523 } 1524 1525 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1526 1527 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1528 { 1529 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1530 struct tcp_sock *tp = tcp_sk(sk); 1531 s32 delta; 1532 1533 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) || 1534 tp->packets_out || ca_ops->cong_control) 1535 return; 1536 delta = tcp_jiffies32 - tp->lsndtime; 1537 if (delta > inet_csk(sk)->icsk_rto) 1538 tcp_cwnd_restart(sk, delta); 1539 } 1540 1541 /* Determine a window scaling and initial window to offer. */ 1542 void tcp_select_initial_window(const struct sock *sk, int __space, 1543 __u32 mss, __u32 *rcv_wnd, 1544 __u32 *window_clamp, int wscale_ok, 1545 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1546 1547 static inline int __tcp_win_from_space(u8 scaling_ratio, int space) 1548 { 1549 s64 scaled_space = (s64)space * scaling_ratio; 1550 1551 return scaled_space >> TCP_RMEM_TO_WIN_SCALE; 1552 } 1553 1554 static inline int tcp_win_from_space(const struct sock *sk, int space) 1555 { 1556 return __tcp_win_from_space(tcp_sk(sk)->scaling_ratio, space); 1557 } 1558 1559 /* inverse of __tcp_win_from_space() */ 1560 static inline int __tcp_space_from_win(u8 scaling_ratio, int win) 1561 { 1562 u64 val = (u64)win << TCP_RMEM_TO_WIN_SCALE; 1563 1564 do_div(val, scaling_ratio); 1565 return val; 1566 } 1567 1568 static inline int tcp_space_from_win(const struct sock *sk, int win) 1569 { 1570 return __tcp_space_from_win(tcp_sk(sk)->scaling_ratio, win); 1571 } 1572 1573 /* Assume a 50% default for skb->len/skb->truesize ratio. 1574 * This may be adjusted later in tcp_measure_rcv_mss(). 1575 */ 1576 #define TCP_DEFAULT_SCALING_RATIO (1 << (TCP_RMEM_TO_WIN_SCALE - 1)) 1577 1578 static inline void tcp_scaling_ratio_init(struct sock *sk) 1579 { 1580 tcp_sk(sk)->scaling_ratio = TCP_DEFAULT_SCALING_RATIO; 1581 } 1582 1583 /* Note: caller must be prepared to deal with negative returns */ 1584 static inline int tcp_space(const struct sock *sk) 1585 { 1586 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1587 READ_ONCE(sk->sk_backlog.len) - 1588 atomic_read(&sk->sk_rmem_alloc)); 1589 } 1590 1591 static inline int tcp_full_space(const struct sock *sk) 1592 { 1593 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1594 } 1595 1596 static inline void __tcp_adjust_rcv_ssthresh(struct sock *sk, u32 new_ssthresh) 1597 { 1598 int unused_mem = sk_unused_reserved_mem(sk); 1599 struct tcp_sock *tp = tcp_sk(sk); 1600 1601 tp->rcv_ssthresh = min(tp->rcv_ssthresh, new_ssthresh); 1602 if (unused_mem) 1603 tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh, 1604 tcp_win_from_space(sk, unused_mem)); 1605 } 1606 1607 static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) 1608 { 1609 __tcp_adjust_rcv_ssthresh(sk, 4U * tcp_sk(sk)->advmss); 1610 } 1611 1612 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1613 void __tcp_cleanup_rbuf(struct sock *sk, int copied); 1614 1615 1616 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1617 * If 87.5 % (7/8) of the space has been consumed, we want to override 1618 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1619 * len/truesize ratio. 1620 */ 1621 static inline bool tcp_rmem_pressure(const struct sock *sk) 1622 { 1623 int rcvbuf, threshold; 1624 1625 if (tcp_under_memory_pressure(sk)) 1626 return true; 1627 1628 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1629 threshold = rcvbuf - (rcvbuf >> 3); 1630 1631 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1632 } 1633 1634 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1635 { 1636 const struct tcp_sock *tp = tcp_sk(sk); 1637 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1638 1639 if (avail <= 0) 1640 return false; 1641 1642 return (avail >= target) || tcp_rmem_pressure(sk) || 1643 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1644 } 1645 1646 extern void tcp_openreq_init_rwin(struct request_sock *req, 1647 const struct sock *sk_listener, 1648 const struct dst_entry *dst); 1649 1650 void tcp_enter_memory_pressure(struct sock *sk); 1651 void tcp_leave_memory_pressure(struct sock *sk); 1652 1653 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1654 { 1655 struct net *net = sock_net((struct sock *)tp); 1656 int val; 1657 1658 /* Paired with WRITE_ONCE() in tcp_sock_set_keepintvl() 1659 * and do_tcp_setsockopt(). 1660 */ 1661 val = READ_ONCE(tp->keepalive_intvl); 1662 1663 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); 1664 } 1665 1666 static inline int keepalive_time_when(const struct tcp_sock *tp) 1667 { 1668 struct net *net = sock_net((struct sock *)tp); 1669 int val; 1670 1671 /* Paired with WRITE_ONCE() in tcp_sock_set_keepidle_locked() */ 1672 val = READ_ONCE(tp->keepalive_time); 1673 1674 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); 1675 } 1676 1677 static inline int keepalive_probes(const struct tcp_sock *tp) 1678 { 1679 struct net *net = sock_net((struct sock *)tp); 1680 int val; 1681 1682 /* Paired with WRITE_ONCE() in tcp_sock_set_keepcnt() 1683 * and do_tcp_setsockopt(). 1684 */ 1685 val = READ_ONCE(tp->keepalive_probes); 1686 1687 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); 1688 } 1689 1690 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1691 { 1692 const struct inet_connection_sock *icsk = &tp->inet_conn; 1693 1694 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1695 tcp_jiffies32 - tp->rcv_tstamp); 1696 } 1697 1698 static inline int tcp_fin_time(const struct sock *sk) 1699 { 1700 int fin_timeout = tcp_sk(sk)->linger2 ? : 1701 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); 1702 const int rto = inet_csk(sk)->icsk_rto; 1703 1704 if (fin_timeout < (rto << 2) - (rto >> 1)) 1705 fin_timeout = (rto << 2) - (rto >> 1); 1706 1707 return fin_timeout; 1708 } 1709 1710 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1711 int paws_win) 1712 { 1713 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1714 return true; 1715 if (unlikely(!time_before32(ktime_get_seconds(), 1716 rx_opt->ts_recent_stamp + TCP_PAWS_WRAP))) 1717 return true; 1718 /* 1719 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1720 * then following tcp messages have valid values. Ignore 0 value, 1721 * or else 'negative' tsval might forbid us to accept their packets. 1722 */ 1723 if (!rx_opt->ts_recent) 1724 return true; 1725 return false; 1726 } 1727 1728 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1729 int rst) 1730 { 1731 if (tcp_paws_check(rx_opt, 0)) 1732 return false; 1733 1734 /* RST segments are not recommended to carry timestamp, 1735 and, if they do, it is recommended to ignore PAWS because 1736 "their cleanup function should take precedence over timestamps." 1737 Certainly, it is mistake. It is necessary to understand the reasons 1738 of this constraint to relax it: if peer reboots, clock may go 1739 out-of-sync and half-open connections will not be reset. 1740 Actually, the problem would be not existing if all 1741 the implementations followed draft about maintaining clock 1742 via reboots. Linux-2.2 DOES NOT! 1743 1744 However, we can relax time bounds for RST segments to MSL. 1745 */ 1746 if (rst && !time_before32(ktime_get_seconds(), 1747 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1748 return false; 1749 return true; 1750 } 1751 1752 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1753 int mib_idx, u32 *last_oow_ack_time); 1754 1755 static inline void tcp_mib_init(struct net *net) 1756 { 1757 /* See RFC 2012 */ 1758 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1759 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1760 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1761 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1762 } 1763 1764 /* from STCP */ 1765 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1766 { 1767 tp->lost_skb_hint = NULL; 1768 } 1769 1770 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1771 { 1772 tcp_clear_retrans_hints_partial(tp); 1773 tp->retransmit_skb_hint = NULL; 1774 } 1775 1776 #define tcp_md5_addr tcp_ao_addr 1777 1778 /* - key database */ 1779 struct tcp_md5sig_key { 1780 struct hlist_node node; 1781 u8 keylen; 1782 u8 family; /* AF_INET or AF_INET6 */ 1783 u8 prefixlen; 1784 u8 flags; 1785 union tcp_md5_addr addr; 1786 int l3index; /* set if key added with L3 scope */ 1787 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1788 struct rcu_head rcu; 1789 }; 1790 1791 /* - sock block */ 1792 struct tcp_md5sig_info { 1793 struct hlist_head head; 1794 struct rcu_head rcu; 1795 }; 1796 1797 /* - pseudo header */ 1798 struct tcp4_pseudohdr { 1799 __be32 saddr; 1800 __be32 daddr; 1801 __u8 pad; 1802 __u8 protocol; 1803 __be16 len; 1804 }; 1805 1806 struct tcp6_pseudohdr { 1807 struct in6_addr saddr; 1808 struct in6_addr daddr; 1809 __be32 len; 1810 __be32 protocol; /* including padding */ 1811 }; 1812 1813 union tcp_md5sum_block { 1814 struct tcp4_pseudohdr ip4; 1815 #if IS_ENABLED(CONFIG_IPV6) 1816 struct tcp6_pseudohdr ip6; 1817 #endif 1818 }; 1819 1820 /* 1821 * struct tcp_sigpool - per-CPU pool of ahash_requests 1822 * @scratch: per-CPU temporary area, that can be used between 1823 * tcp_sigpool_start() and tcp_sigpool_end() to perform 1824 * crypto request 1825 * @req: pre-allocated ahash request 1826 */ 1827 struct tcp_sigpool { 1828 void *scratch; 1829 struct ahash_request *req; 1830 }; 1831 1832 int tcp_sigpool_alloc_ahash(const char *alg, size_t scratch_size); 1833 void tcp_sigpool_get(unsigned int id); 1834 void tcp_sigpool_release(unsigned int id); 1835 int tcp_sigpool_hash_skb_data(struct tcp_sigpool *hp, 1836 const struct sk_buff *skb, 1837 unsigned int header_len); 1838 1839 /** 1840 * tcp_sigpool_start - disable bh and start using tcp_sigpool_ahash 1841 * @id: tcp_sigpool that was previously allocated by tcp_sigpool_alloc_ahash() 1842 * @c: returned tcp_sigpool for usage (uninitialized on failure) 1843 * 1844 * Returns: 0 on success, error otherwise. 1845 */ 1846 int tcp_sigpool_start(unsigned int id, struct tcp_sigpool *c); 1847 /** 1848 * tcp_sigpool_end - enable bh and stop using tcp_sigpool 1849 * @c: tcp_sigpool context that was returned by tcp_sigpool_start() 1850 */ 1851 void tcp_sigpool_end(struct tcp_sigpool *c); 1852 size_t tcp_sigpool_algo(unsigned int id, char *buf, size_t buf_len); 1853 /* - functions */ 1854 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1855 const struct sock *sk, const struct sk_buff *skb); 1856 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1857 int family, u8 prefixlen, int l3index, u8 flags, 1858 const u8 *newkey, u8 newkeylen); 1859 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1860 int family, u8 prefixlen, int l3index, 1861 struct tcp_md5sig_key *key); 1862 1863 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1864 int family, u8 prefixlen, int l3index, u8 flags); 1865 void tcp_clear_md5_list(struct sock *sk); 1866 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1867 const struct sock *addr_sk); 1868 1869 #ifdef CONFIG_TCP_MD5SIG 1870 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1871 const union tcp_md5_addr *addr, 1872 int family, bool any_l3index); 1873 static inline struct tcp_md5sig_key * 1874 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1875 const union tcp_md5_addr *addr, int family) 1876 { 1877 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1878 return NULL; 1879 return __tcp_md5_do_lookup(sk, l3index, addr, family, false); 1880 } 1881 1882 static inline struct tcp_md5sig_key * 1883 tcp_md5_do_lookup_any_l3index(const struct sock *sk, 1884 const union tcp_md5_addr *addr, int family) 1885 { 1886 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1887 return NULL; 1888 return __tcp_md5_do_lookup(sk, 0, addr, family, true); 1889 } 1890 1891 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1892 #else 1893 static inline struct tcp_md5sig_key * 1894 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1895 const union tcp_md5_addr *addr, int family) 1896 { 1897 return NULL; 1898 } 1899 1900 static inline struct tcp_md5sig_key * 1901 tcp_md5_do_lookup_any_l3index(const struct sock *sk, 1902 const union tcp_md5_addr *addr, int family) 1903 { 1904 return NULL; 1905 } 1906 1907 #define tcp_twsk_md5_key(twsk) NULL 1908 #endif 1909 1910 int tcp_md5_alloc_sigpool(void); 1911 void tcp_md5_release_sigpool(void); 1912 void tcp_md5_add_sigpool(void); 1913 extern int tcp_md5_sigpool_id; 1914 1915 int tcp_md5_hash_key(struct tcp_sigpool *hp, 1916 const struct tcp_md5sig_key *key); 1917 1918 /* From tcp_fastopen.c */ 1919 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1920 struct tcp_fastopen_cookie *cookie); 1921 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1922 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1923 u16 try_exp); 1924 struct tcp_fastopen_request { 1925 /* Fast Open cookie. Size 0 means a cookie request */ 1926 struct tcp_fastopen_cookie cookie; 1927 struct msghdr *data; /* data in MSG_FASTOPEN */ 1928 size_t size; 1929 int copied; /* queued in tcp_connect() */ 1930 struct ubuf_info *uarg; 1931 }; 1932 void tcp_free_fastopen_req(struct tcp_sock *tp); 1933 void tcp_fastopen_destroy_cipher(struct sock *sk); 1934 void tcp_fastopen_ctx_destroy(struct net *net); 1935 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1936 void *primary_key, void *backup_key); 1937 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1938 u64 *key); 1939 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1940 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1941 struct request_sock *req, 1942 struct tcp_fastopen_cookie *foc, 1943 const struct dst_entry *dst); 1944 void tcp_fastopen_init_key_once(struct net *net); 1945 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1946 struct tcp_fastopen_cookie *cookie); 1947 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1948 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1949 #define TCP_FASTOPEN_KEY_MAX 2 1950 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1951 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1952 1953 /* Fastopen key context */ 1954 struct tcp_fastopen_context { 1955 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1956 int num; 1957 struct rcu_head rcu; 1958 }; 1959 1960 void tcp_fastopen_active_disable(struct sock *sk); 1961 bool tcp_fastopen_active_should_disable(struct sock *sk); 1962 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1963 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1964 1965 /* Caller needs to wrap with rcu_read_(un)lock() */ 1966 static inline 1967 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1968 { 1969 struct tcp_fastopen_context *ctx; 1970 1971 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1972 if (!ctx) 1973 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1974 return ctx; 1975 } 1976 1977 static inline 1978 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1979 const struct tcp_fastopen_cookie *orig) 1980 { 1981 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1982 orig->len == foc->len && 1983 !memcmp(orig->val, foc->val, foc->len)) 1984 return true; 1985 return false; 1986 } 1987 1988 static inline 1989 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1990 { 1991 return ctx->num; 1992 } 1993 1994 /* Latencies incurred by various limits for a sender. They are 1995 * chronograph-like stats that are mutually exclusive. 1996 */ 1997 enum tcp_chrono { 1998 TCP_CHRONO_UNSPEC, 1999 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 2000 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 2001 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 2002 __TCP_CHRONO_MAX, 2003 }; 2004 2005 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 2006 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 2007 2008 /* This helper is needed, because skb->tcp_tsorted_anchor uses 2009 * the same memory storage than skb->destructor/_skb_refdst 2010 */ 2011 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 2012 { 2013 skb->destructor = NULL; 2014 skb->_skb_refdst = 0UL; 2015 } 2016 2017 #define tcp_skb_tsorted_save(skb) { \ 2018 unsigned long _save = skb->_skb_refdst; \ 2019 skb->_skb_refdst = 0UL; 2020 2021 #define tcp_skb_tsorted_restore(skb) \ 2022 skb->_skb_refdst = _save; \ 2023 } 2024 2025 void tcp_write_queue_purge(struct sock *sk); 2026 2027 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 2028 { 2029 return skb_rb_first(&sk->tcp_rtx_queue); 2030 } 2031 2032 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 2033 { 2034 return skb_rb_last(&sk->tcp_rtx_queue); 2035 } 2036 2037 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 2038 { 2039 return skb_peek_tail(&sk->sk_write_queue); 2040 } 2041 2042 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 2043 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 2044 2045 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 2046 { 2047 return skb_peek(&sk->sk_write_queue); 2048 } 2049 2050 static inline bool tcp_skb_is_last(const struct sock *sk, 2051 const struct sk_buff *skb) 2052 { 2053 return skb_queue_is_last(&sk->sk_write_queue, skb); 2054 } 2055 2056 /** 2057 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 2058 * @sk: socket 2059 * 2060 * Since the write queue can have a temporary empty skb in it, 2061 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 2062 */ 2063 static inline bool tcp_write_queue_empty(const struct sock *sk) 2064 { 2065 const struct tcp_sock *tp = tcp_sk(sk); 2066 2067 return tp->write_seq == tp->snd_nxt; 2068 } 2069 2070 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 2071 { 2072 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 2073 } 2074 2075 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 2076 { 2077 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 2078 } 2079 2080 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 2081 { 2082 __skb_queue_tail(&sk->sk_write_queue, skb); 2083 2084 /* Queue it, remembering where we must start sending. */ 2085 if (sk->sk_write_queue.next == skb) 2086 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 2087 } 2088 2089 /* Insert new before skb on the write queue of sk. */ 2090 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 2091 struct sk_buff *skb, 2092 struct sock *sk) 2093 { 2094 __skb_queue_before(&sk->sk_write_queue, skb, new); 2095 } 2096 2097 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 2098 { 2099 tcp_skb_tsorted_anchor_cleanup(skb); 2100 __skb_unlink(skb, &sk->sk_write_queue); 2101 } 2102 2103 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 2104 2105 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 2106 { 2107 tcp_skb_tsorted_anchor_cleanup(skb); 2108 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 2109 } 2110 2111 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 2112 { 2113 list_del(&skb->tcp_tsorted_anchor); 2114 tcp_rtx_queue_unlink(skb, sk); 2115 tcp_wmem_free_skb(sk, skb); 2116 } 2117 2118 static inline void tcp_write_collapse_fence(struct sock *sk) 2119 { 2120 struct sk_buff *skb = tcp_write_queue_tail(sk); 2121 2122 if (skb) 2123 TCP_SKB_CB(skb)->eor = 1; 2124 } 2125 2126 static inline void tcp_push_pending_frames(struct sock *sk) 2127 { 2128 if (tcp_send_head(sk)) { 2129 struct tcp_sock *tp = tcp_sk(sk); 2130 2131 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 2132 } 2133 } 2134 2135 /* Start sequence of the skb just after the highest skb with SACKed 2136 * bit, valid only if sacked_out > 0 or when the caller has ensured 2137 * validity by itself. 2138 */ 2139 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 2140 { 2141 if (!tp->sacked_out) 2142 return tp->snd_una; 2143 2144 if (tp->highest_sack == NULL) 2145 return tp->snd_nxt; 2146 2147 return TCP_SKB_CB(tp->highest_sack)->seq; 2148 } 2149 2150 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 2151 { 2152 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 2153 } 2154 2155 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 2156 { 2157 return tcp_sk(sk)->highest_sack; 2158 } 2159 2160 static inline void tcp_highest_sack_reset(struct sock *sk) 2161 { 2162 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 2163 } 2164 2165 /* Called when old skb is about to be deleted and replaced by new skb */ 2166 static inline void tcp_highest_sack_replace(struct sock *sk, 2167 struct sk_buff *old, 2168 struct sk_buff *new) 2169 { 2170 if (old == tcp_highest_sack(sk)) 2171 tcp_sk(sk)->highest_sack = new; 2172 } 2173 2174 /* This helper checks if socket has IP_TRANSPARENT set */ 2175 static inline bool inet_sk_transparent(const struct sock *sk) 2176 { 2177 switch (sk->sk_state) { 2178 case TCP_TIME_WAIT: 2179 return inet_twsk(sk)->tw_transparent; 2180 case TCP_NEW_SYN_RECV: 2181 return inet_rsk(inet_reqsk(sk))->no_srccheck; 2182 } 2183 return inet_test_bit(TRANSPARENT, sk); 2184 } 2185 2186 /* Determines whether this is a thin stream (which may suffer from 2187 * increased latency). Used to trigger latency-reducing mechanisms. 2188 */ 2189 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 2190 { 2191 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 2192 } 2193 2194 /* /proc */ 2195 enum tcp_seq_states { 2196 TCP_SEQ_STATE_LISTENING, 2197 TCP_SEQ_STATE_ESTABLISHED, 2198 }; 2199 2200 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 2201 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 2202 void tcp_seq_stop(struct seq_file *seq, void *v); 2203 2204 struct tcp_seq_afinfo { 2205 sa_family_t family; 2206 }; 2207 2208 struct tcp_iter_state { 2209 struct seq_net_private p; 2210 enum tcp_seq_states state; 2211 struct sock *syn_wait_sk; 2212 int bucket, offset, sbucket, num; 2213 loff_t last_pos; 2214 }; 2215 2216 extern struct request_sock_ops tcp_request_sock_ops; 2217 extern struct request_sock_ops tcp6_request_sock_ops; 2218 2219 void tcp_v4_destroy_sock(struct sock *sk); 2220 2221 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 2222 netdev_features_t features); 2223 struct tcphdr *tcp_gro_pull_header(struct sk_buff *skb); 2224 struct sk_buff *tcp_gro_lookup(struct list_head *head, struct tcphdr *th); 2225 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb, 2226 struct tcphdr *th); 2227 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 2228 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 2229 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 2230 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 2231 #ifdef CONFIG_INET 2232 void tcp_gro_complete(struct sk_buff *skb); 2233 #else 2234 static inline void tcp_gro_complete(struct sk_buff *skb) { } 2235 #endif 2236 2237 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 2238 2239 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 2240 { 2241 struct net *net = sock_net((struct sock *)tp); 2242 u32 val; 2243 2244 val = READ_ONCE(tp->notsent_lowat); 2245 2246 return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); 2247 } 2248 2249 bool tcp_stream_memory_free(const struct sock *sk, int wake); 2250 2251 #ifdef CONFIG_PROC_FS 2252 int tcp4_proc_init(void); 2253 void tcp4_proc_exit(void); 2254 #endif 2255 2256 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2257 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2258 const struct tcp_request_sock_ops *af_ops, 2259 struct sock *sk, struct sk_buff *skb); 2260 2261 /* TCP af-specific functions */ 2262 struct tcp_sock_af_ops { 2263 #ifdef CONFIG_TCP_MD5SIG 2264 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2265 const struct sock *addr_sk); 2266 int (*calc_md5_hash)(char *location, 2267 const struct tcp_md5sig_key *md5, 2268 const struct sock *sk, 2269 const struct sk_buff *skb); 2270 int (*md5_parse)(struct sock *sk, 2271 int optname, 2272 sockptr_t optval, 2273 int optlen); 2274 #endif 2275 #ifdef CONFIG_TCP_AO 2276 int (*ao_parse)(struct sock *sk, int optname, sockptr_t optval, int optlen); 2277 struct tcp_ao_key *(*ao_lookup)(const struct sock *sk, 2278 struct sock *addr_sk, 2279 int sndid, int rcvid); 2280 int (*ao_calc_key_sk)(struct tcp_ao_key *mkt, u8 *key, 2281 const struct sock *sk, 2282 __be32 sisn, __be32 disn, bool send); 2283 int (*calc_ao_hash)(char *location, struct tcp_ao_key *ao, 2284 const struct sock *sk, const struct sk_buff *skb, 2285 const u8 *tkey, int hash_offset, u32 sne); 2286 #endif 2287 }; 2288 2289 struct tcp_request_sock_ops { 2290 u16 mss_clamp; 2291 #ifdef CONFIG_TCP_MD5SIG 2292 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2293 const struct sock *addr_sk); 2294 int (*calc_md5_hash) (char *location, 2295 const struct tcp_md5sig_key *md5, 2296 const struct sock *sk, 2297 const struct sk_buff *skb); 2298 #endif 2299 #ifdef CONFIG_TCP_AO 2300 struct tcp_ao_key *(*ao_lookup)(const struct sock *sk, 2301 struct request_sock *req, 2302 int sndid, int rcvid); 2303 int (*ao_calc_key)(struct tcp_ao_key *mkt, u8 *key, struct request_sock *sk); 2304 int (*ao_synack_hash)(char *ao_hash, struct tcp_ao_key *mkt, 2305 struct request_sock *req, const struct sk_buff *skb, 2306 int hash_offset, u32 sne); 2307 #endif 2308 #ifdef CONFIG_SYN_COOKIES 2309 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2310 __u16 *mss); 2311 #endif 2312 struct dst_entry *(*route_req)(const struct sock *sk, 2313 struct sk_buff *skb, 2314 struct flowi *fl, 2315 struct request_sock *req, 2316 u32 tw_isn); 2317 u32 (*init_seq)(const struct sk_buff *skb); 2318 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2319 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2320 struct flowi *fl, struct request_sock *req, 2321 struct tcp_fastopen_cookie *foc, 2322 enum tcp_synack_type synack_type, 2323 struct sk_buff *syn_skb); 2324 }; 2325 2326 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2327 #if IS_ENABLED(CONFIG_IPV6) 2328 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2329 #endif 2330 2331 #ifdef CONFIG_SYN_COOKIES 2332 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2333 const struct sock *sk, struct sk_buff *skb, 2334 __u16 *mss) 2335 { 2336 tcp_synq_overflow(sk); 2337 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2338 return ops->cookie_init_seq(skb, mss); 2339 } 2340 #else 2341 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2342 const struct sock *sk, struct sk_buff *skb, 2343 __u16 *mss) 2344 { 2345 return 0; 2346 } 2347 #endif 2348 2349 struct tcp_key { 2350 union { 2351 struct { 2352 struct tcp_ao_key *ao_key; 2353 char *traffic_key; 2354 u32 sne; 2355 u8 rcv_next; 2356 }; 2357 struct tcp_md5sig_key *md5_key; 2358 }; 2359 enum { 2360 TCP_KEY_NONE = 0, 2361 TCP_KEY_MD5, 2362 TCP_KEY_AO, 2363 } type; 2364 }; 2365 2366 static inline void tcp_get_current_key(const struct sock *sk, 2367 struct tcp_key *out) 2368 { 2369 #if defined(CONFIG_TCP_AO) || defined(CONFIG_TCP_MD5SIG) 2370 const struct tcp_sock *tp = tcp_sk(sk); 2371 #endif 2372 2373 #ifdef CONFIG_TCP_AO 2374 if (static_branch_unlikely(&tcp_ao_needed.key)) { 2375 struct tcp_ao_info *ao; 2376 2377 ao = rcu_dereference_protected(tp->ao_info, 2378 lockdep_sock_is_held(sk)); 2379 if (ao) { 2380 out->ao_key = READ_ONCE(ao->current_key); 2381 out->type = TCP_KEY_AO; 2382 return; 2383 } 2384 } 2385 #endif 2386 #ifdef CONFIG_TCP_MD5SIG 2387 if (static_branch_unlikely(&tcp_md5_needed.key) && 2388 rcu_access_pointer(tp->md5sig_info)) { 2389 out->md5_key = tp->af_specific->md5_lookup(sk, sk); 2390 if (out->md5_key) { 2391 out->type = TCP_KEY_MD5; 2392 return; 2393 } 2394 } 2395 #endif 2396 out->type = TCP_KEY_NONE; 2397 } 2398 2399 static inline bool tcp_key_is_md5(const struct tcp_key *key) 2400 { 2401 if (static_branch_tcp_md5()) 2402 return key->type == TCP_KEY_MD5; 2403 return false; 2404 } 2405 2406 static inline bool tcp_key_is_ao(const struct tcp_key *key) 2407 { 2408 if (static_branch_tcp_ao()) 2409 return key->type == TCP_KEY_AO; 2410 return false; 2411 } 2412 2413 int tcpv4_offload_init(void); 2414 2415 void tcp_v4_init(void); 2416 void tcp_init(void); 2417 2418 /* tcp_recovery.c */ 2419 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2420 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2421 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2422 u32 reo_wnd); 2423 extern bool tcp_rack_mark_lost(struct sock *sk); 2424 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2425 u64 xmit_time); 2426 extern void tcp_rack_reo_timeout(struct sock *sk); 2427 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2428 2429 /* tcp_plb.c */ 2430 2431 /* 2432 * Scaling factor for fractions in PLB. For example, tcp_plb_update_state 2433 * expects cong_ratio which represents fraction of traffic that experienced 2434 * congestion over a single RTT. In order to avoid floating point operations, 2435 * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in. 2436 */ 2437 #define TCP_PLB_SCALE 8 2438 2439 /* State for PLB (Protective Load Balancing) for a single TCP connection. */ 2440 struct tcp_plb_state { 2441 u8 consec_cong_rounds:5, /* consecutive congested rounds */ 2442 unused:3; 2443 u32 pause_until; /* jiffies32 when PLB can resume rerouting */ 2444 }; 2445 2446 static inline void tcp_plb_init(const struct sock *sk, 2447 struct tcp_plb_state *plb) 2448 { 2449 plb->consec_cong_rounds = 0; 2450 plb->pause_until = 0; 2451 } 2452 void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb, 2453 const int cong_ratio); 2454 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb); 2455 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb); 2456 2457 static inline void tcp_warn_once(const struct sock *sk, bool cond, const char *str) 2458 { 2459 WARN_ONCE(cond, 2460 "%scwn:%u out:%u sacked:%u lost:%u retrans:%u tlp_high_seq:%u sk_state:%u ca_state:%u advmss:%u mss_cache:%u pmtu:%u\n", 2461 str, 2462 tcp_snd_cwnd(tcp_sk(sk)), 2463 tcp_sk(sk)->packets_out, tcp_sk(sk)->sacked_out, 2464 tcp_sk(sk)->lost_out, tcp_sk(sk)->retrans_out, 2465 tcp_sk(sk)->tlp_high_seq, sk->sk_state, 2466 inet_csk(sk)->icsk_ca_state, 2467 tcp_sk(sk)->advmss, tcp_sk(sk)->mss_cache, 2468 inet_csk(sk)->icsk_pmtu_cookie); 2469 } 2470 2471 /* At how many usecs into the future should the RTO fire? */ 2472 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2473 { 2474 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2475 u32 rto = inet_csk(sk)->icsk_rto; 2476 2477 if (likely(skb)) { 2478 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2479 2480 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2481 } else { 2482 tcp_warn_once(sk, 1, "rtx queue empty: "); 2483 return jiffies_to_usecs(rto); 2484 } 2485 2486 } 2487 2488 /* 2489 * Save and compile IPv4 options, return a pointer to it 2490 */ 2491 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2492 struct sk_buff *skb) 2493 { 2494 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2495 struct ip_options_rcu *dopt = NULL; 2496 2497 if (opt->optlen) { 2498 int opt_size = sizeof(*dopt) + opt->optlen; 2499 2500 dopt = kmalloc(opt_size, GFP_ATOMIC); 2501 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2502 kfree(dopt); 2503 dopt = NULL; 2504 } 2505 } 2506 return dopt; 2507 } 2508 2509 /* locally generated TCP pure ACKs have skb->truesize == 2 2510 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2511 * This is much faster than dissecting the packet to find out. 2512 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2513 */ 2514 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2515 { 2516 return skb->truesize == 2; 2517 } 2518 2519 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2520 { 2521 skb->truesize = 2; 2522 } 2523 2524 static inline int tcp_inq(struct sock *sk) 2525 { 2526 struct tcp_sock *tp = tcp_sk(sk); 2527 int answ; 2528 2529 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2530 answ = 0; 2531 } else if (sock_flag(sk, SOCK_URGINLINE) || 2532 !tp->urg_data || 2533 before(tp->urg_seq, tp->copied_seq) || 2534 !before(tp->urg_seq, tp->rcv_nxt)) { 2535 2536 answ = tp->rcv_nxt - tp->copied_seq; 2537 2538 /* Subtract 1, if FIN was received */ 2539 if (answ && sock_flag(sk, SOCK_DONE)) 2540 answ--; 2541 } else { 2542 answ = tp->urg_seq - tp->copied_seq; 2543 } 2544 2545 return answ; 2546 } 2547 2548 int tcp_peek_len(struct socket *sock); 2549 2550 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2551 { 2552 u16 segs_in; 2553 2554 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2555 2556 /* We update these fields while other threads might 2557 * read them from tcp_get_info() 2558 */ 2559 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2560 if (skb->len > tcp_hdrlen(skb)) 2561 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2562 } 2563 2564 /* 2565 * TCP listen path runs lockless. 2566 * We forced "struct sock" to be const qualified to make sure 2567 * we don't modify one of its field by mistake. 2568 * Here, we increment sk_drops which is an atomic_t, so we can safely 2569 * make sock writable again. 2570 */ 2571 static inline void tcp_listendrop(const struct sock *sk) 2572 { 2573 atomic_inc(&((struct sock *)sk)->sk_drops); 2574 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2575 } 2576 2577 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2578 2579 /* 2580 * Interface for adding Upper Level Protocols over TCP 2581 */ 2582 2583 #define TCP_ULP_NAME_MAX 16 2584 #define TCP_ULP_MAX 128 2585 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2586 2587 struct tcp_ulp_ops { 2588 struct list_head list; 2589 2590 /* initialize ulp */ 2591 int (*init)(struct sock *sk); 2592 /* update ulp */ 2593 void (*update)(struct sock *sk, struct proto *p, 2594 void (*write_space)(struct sock *sk)); 2595 /* cleanup ulp */ 2596 void (*release)(struct sock *sk); 2597 /* diagnostic */ 2598 int (*get_info)(struct sock *sk, struct sk_buff *skb); 2599 size_t (*get_info_size)(const struct sock *sk); 2600 /* clone ulp */ 2601 void (*clone)(const struct request_sock *req, struct sock *newsk, 2602 const gfp_t priority); 2603 2604 char name[TCP_ULP_NAME_MAX]; 2605 struct module *owner; 2606 }; 2607 int tcp_register_ulp(struct tcp_ulp_ops *type); 2608 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2609 int tcp_set_ulp(struct sock *sk, const char *name); 2610 void tcp_get_available_ulp(char *buf, size_t len); 2611 void tcp_cleanup_ulp(struct sock *sk); 2612 void tcp_update_ulp(struct sock *sk, struct proto *p, 2613 void (*write_space)(struct sock *sk)); 2614 2615 #define MODULE_ALIAS_TCP_ULP(name) \ 2616 __MODULE_INFO(alias, alias_userspace, name); \ 2617 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2618 2619 #ifdef CONFIG_NET_SOCK_MSG 2620 struct sk_msg; 2621 struct sk_psock; 2622 2623 #ifdef CONFIG_BPF_SYSCALL 2624 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2625 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2626 #endif /* CONFIG_BPF_SYSCALL */ 2627 2628 #ifdef CONFIG_INET 2629 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); 2630 #else 2631 static inline void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) 2632 { 2633 } 2634 #endif 2635 2636 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 2637 struct sk_msg *msg, u32 bytes, int flags); 2638 #endif /* CONFIG_NET_SOCK_MSG */ 2639 2640 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2641 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2642 { 2643 } 2644 #endif 2645 2646 #ifdef CONFIG_CGROUP_BPF 2647 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2648 struct sk_buff *skb, 2649 unsigned int end_offset) 2650 { 2651 skops->skb = skb; 2652 skops->skb_data_end = skb->data + end_offset; 2653 } 2654 #else 2655 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2656 struct sk_buff *skb, 2657 unsigned int end_offset) 2658 { 2659 } 2660 #endif 2661 2662 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2663 * is < 0, then the BPF op failed (for example if the loaded BPF 2664 * program does not support the chosen operation or there is no BPF 2665 * program loaded). 2666 */ 2667 #ifdef CONFIG_BPF 2668 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2669 { 2670 struct bpf_sock_ops_kern sock_ops; 2671 int ret; 2672 2673 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2674 if (sk_fullsock(sk)) { 2675 sock_ops.is_fullsock = 1; 2676 sock_ops.is_locked_tcp_sock = 1; 2677 sock_owned_by_me(sk); 2678 } 2679 2680 sock_ops.sk = sk; 2681 sock_ops.op = op; 2682 if (nargs > 0) 2683 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2684 2685 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2686 if (ret == 0) 2687 ret = sock_ops.reply; 2688 else 2689 ret = -1; 2690 return ret; 2691 } 2692 2693 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2694 { 2695 u32 args[2] = {arg1, arg2}; 2696 2697 return tcp_call_bpf(sk, op, 2, args); 2698 } 2699 2700 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2701 u32 arg3) 2702 { 2703 u32 args[3] = {arg1, arg2, arg3}; 2704 2705 return tcp_call_bpf(sk, op, 3, args); 2706 } 2707 2708 #else 2709 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2710 { 2711 return -EPERM; 2712 } 2713 2714 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2715 { 2716 return -EPERM; 2717 } 2718 2719 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2720 u32 arg3) 2721 { 2722 return -EPERM; 2723 } 2724 2725 #endif 2726 2727 static inline u32 tcp_timeout_init(struct sock *sk) 2728 { 2729 int timeout; 2730 2731 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2732 2733 if (timeout <= 0) 2734 timeout = TCP_TIMEOUT_INIT; 2735 return min_t(int, timeout, TCP_RTO_MAX); 2736 } 2737 2738 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2739 { 2740 int rwnd; 2741 2742 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2743 2744 if (rwnd < 0) 2745 rwnd = 0; 2746 return rwnd; 2747 } 2748 2749 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2750 { 2751 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2752 } 2753 2754 static inline void tcp_bpf_rtt(struct sock *sk, long mrtt, u32 srtt) 2755 { 2756 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2757 tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_RTT_CB, mrtt, srtt); 2758 } 2759 2760 #if IS_ENABLED(CONFIG_SMC) 2761 extern struct static_key_false tcp_have_smc; 2762 #endif 2763 2764 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2765 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2766 void (*cad)(struct sock *sk, u32 ack_seq)); 2767 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2768 void clean_acked_data_flush(void); 2769 #endif 2770 2771 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2772 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2773 const struct tcp_sock *tp) 2774 { 2775 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2776 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2777 } 2778 2779 /* Compute Earliest Departure Time for some control packets 2780 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2781 */ 2782 static inline u64 tcp_transmit_time(const struct sock *sk) 2783 { 2784 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2785 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2786 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2787 2788 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2789 } 2790 return 0; 2791 } 2792 2793 static inline int tcp_parse_auth_options(const struct tcphdr *th, 2794 const u8 **md5_hash, const struct tcp_ao_hdr **aoh) 2795 { 2796 const u8 *md5_tmp, *ao_tmp; 2797 int ret; 2798 2799 ret = tcp_do_parse_auth_options(th, &md5_tmp, &ao_tmp); 2800 if (ret) 2801 return ret; 2802 2803 if (md5_hash) 2804 *md5_hash = md5_tmp; 2805 2806 if (aoh) { 2807 if (!ao_tmp) 2808 *aoh = NULL; 2809 else 2810 *aoh = (struct tcp_ao_hdr *)(ao_tmp - 2); 2811 } 2812 2813 return 0; 2814 } 2815 2816 static inline bool tcp_ao_required(struct sock *sk, const void *saddr, 2817 int family, int l3index, bool stat_inc) 2818 { 2819 #ifdef CONFIG_TCP_AO 2820 struct tcp_ao_info *ao_info; 2821 struct tcp_ao_key *ao_key; 2822 2823 if (!static_branch_unlikely(&tcp_ao_needed.key)) 2824 return false; 2825 2826 ao_info = rcu_dereference_check(tcp_sk(sk)->ao_info, 2827 lockdep_sock_is_held(sk)); 2828 if (!ao_info) 2829 return false; 2830 2831 ao_key = tcp_ao_do_lookup(sk, l3index, saddr, family, -1, -1); 2832 if (ao_info->ao_required || ao_key) { 2833 if (stat_inc) { 2834 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOREQUIRED); 2835 atomic64_inc(&ao_info->counters.ao_required); 2836 } 2837 return true; 2838 } 2839 #endif 2840 return false; 2841 } 2842 2843 enum skb_drop_reason tcp_inbound_hash(struct sock *sk, 2844 const struct request_sock *req, const struct sk_buff *skb, 2845 const void *saddr, const void *daddr, 2846 int family, int dif, int sdif); 2847 2848 #endif /* _TCP_H */ 2849