1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Definitions for the TCP module. 8 * 9 * Version: @(#)tcp.h 1.0.5 05/23/93 10 * 11 * Authors: Ross Biro 12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 13 */ 14 #ifndef _TCP_H 15 #define _TCP_H 16 17 #define FASTRETRANS_DEBUG 1 18 19 #include <linux/list.h> 20 #include <linux/tcp.h> 21 #include <linux/bug.h> 22 #include <linux/slab.h> 23 #include <linux/cache.h> 24 #include <linux/percpu.h> 25 #include <linux/skbuff.h> 26 #include <linux/kref.h> 27 #include <linux/ktime.h> 28 #include <linux/indirect_call_wrapper.h> 29 30 #include <net/inet_connection_sock.h> 31 #include <net/inet_timewait_sock.h> 32 #include <net/inet_hashtables.h> 33 #include <net/checksum.h> 34 #include <net/request_sock.h> 35 #include <net/sock_reuseport.h> 36 #include <net/sock.h> 37 #include <net/snmp.h> 38 #include <net/ip.h> 39 #include <net/tcp_states.h> 40 #include <net/tcp_ao.h> 41 #include <net/inet_ecn.h> 42 #include <net/dst.h> 43 #include <net/mptcp.h> 44 45 #include <linux/seq_file.h> 46 #include <linux/memcontrol.h> 47 #include <linux/bpf-cgroup.h> 48 #include <linux/siphash.h> 49 50 extern struct inet_hashinfo tcp_hashinfo; 51 52 DECLARE_PER_CPU(unsigned int, tcp_orphan_count); 53 int tcp_orphan_count_sum(void); 54 55 DECLARE_PER_CPU(u32, tcp_tw_isn); 56 57 void tcp_time_wait(struct sock *sk, int state, int timeo); 58 59 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) 60 #define MAX_TCP_OPTION_SPACE 40 61 #define TCP_MIN_SND_MSS 48 62 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 63 64 /* 65 * Never offer a window over 32767 without using window scaling. Some 66 * poor stacks do signed 16bit maths! 67 */ 68 #define MAX_TCP_WINDOW 32767U 69 70 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 71 #define TCP_MIN_MSS 88U 72 73 /* The initial MTU to use for probing */ 74 #define TCP_BASE_MSS 1024 75 76 /* probing interval, default to 10 minutes as per RFC4821 */ 77 #define TCP_PROBE_INTERVAL 600 78 79 /* Specify interval when tcp mtu probing will stop */ 80 #define TCP_PROBE_THRESHOLD 8 81 82 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 83 #define TCP_FASTRETRANS_THRESH 3 84 85 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 86 #define TCP_MAX_QUICKACKS 16U 87 88 /* Maximal number of window scale according to RFC1323 */ 89 #define TCP_MAX_WSCALE 14U 90 91 /* urg_data states */ 92 #define TCP_URG_VALID 0x0100 93 #define TCP_URG_NOTYET 0x0200 94 #define TCP_URG_READ 0x0400 95 96 #define TCP_RETR1 3 /* 97 * This is how many retries it does before it 98 * tries to figure out if the gateway is 99 * down. Minimal RFC value is 3; it corresponds 100 * to ~3sec-8min depending on RTO. 101 */ 102 103 #define TCP_RETR2 15 /* 104 * This should take at least 105 * 90 minutes to time out. 106 * RFC1122 says that the limit is 100 sec. 107 * 15 is ~13-30min depending on RTO. 108 */ 109 110 #define TCP_SYN_RETRIES 6 /* This is how many retries are done 111 * when active opening a connection. 112 * RFC1122 says the minimum retry MUST 113 * be at least 180secs. Nevertheless 114 * this value is corresponding to 115 * 63secs of retransmission with the 116 * current initial RTO. 117 */ 118 119 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done 120 * when passive opening a connection. 121 * This is corresponding to 31secs of 122 * retransmission with the current 123 * initial RTO. 124 */ 125 126 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 127 * state, about 60 seconds */ 128 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 129 /* BSD style FIN_WAIT2 deadlock breaker. 130 * It used to be 3min, new value is 60sec, 131 * to combine FIN-WAIT-2 timeout with 132 * TIME-WAIT timer. 133 */ 134 #define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */ 135 136 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 137 static_assert((1 << ATO_BITS) > TCP_DELACK_MAX); 138 139 #if HZ >= 100 140 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 141 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 142 #else 143 #define TCP_DELACK_MIN 4U 144 #define TCP_ATO_MIN 4U 145 #endif 146 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 147 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 148 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ 149 150 #define TCP_TIMEOUT_MIN_US (2*USEC_PER_MSEC) /* Min TCP timeout in microsecs */ 151 152 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 153 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 154 * used as a fallback RTO for the 155 * initial data transmission if no 156 * valid RTT sample has been acquired, 157 * most likely due to retrans in 3WHS. 158 */ 159 160 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 161 * for local resources. 162 */ 163 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 164 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 165 #define TCP_KEEPALIVE_INTVL (75*HZ) 166 167 #define MAX_TCP_KEEPIDLE 32767 168 #define MAX_TCP_KEEPINTVL 32767 169 #define MAX_TCP_KEEPCNT 127 170 #define MAX_TCP_SYNCNT 127 171 172 /* Ensure that TCP PAWS checks are relaxed after ~2147 seconds 173 * to avoid overflows. This assumes a clock smaller than 1 Mhz. 174 * Default clock is 1 Khz, tcp_usec_ts uses 1 Mhz. 175 */ 176 #define TCP_PAWS_WRAP (INT_MAX / USEC_PER_SEC) 177 178 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 179 * after this time. It should be equal 180 * (or greater than) TCP_TIMEWAIT_LEN 181 * to provide reliability equal to one 182 * provided by timewait state. 183 */ 184 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 185 * timestamps. It must be less than 186 * minimal timewait lifetime. 187 */ 188 /* 189 * TCP option 190 */ 191 192 #define TCPOPT_NOP 1 /* Padding */ 193 #define TCPOPT_EOL 0 /* End of options */ 194 #define TCPOPT_MSS 2 /* Segment size negotiating */ 195 #define TCPOPT_WINDOW 3 /* Window scaling */ 196 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 197 #define TCPOPT_SACK 5 /* SACK Block */ 198 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 199 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 200 #define TCPOPT_AO 29 /* Authentication Option (RFC5925) */ 201 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ 202 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 203 #define TCPOPT_EXP 254 /* Experimental */ 204 /* Magic number to be after the option value for sharing TCP 205 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 206 */ 207 #define TCPOPT_FASTOPEN_MAGIC 0xF989 208 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 209 210 /* 211 * TCP option lengths 212 */ 213 214 #define TCPOLEN_MSS 4 215 #define TCPOLEN_WINDOW 3 216 #define TCPOLEN_SACK_PERM 2 217 #define TCPOLEN_TIMESTAMP 10 218 #define TCPOLEN_MD5SIG 18 219 #define TCPOLEN_FASTOPEN_BASE 2 220 #define TCPOLEN_EXP_FASTOPEN_BASE 4 221 #define TCPOLEN_EXP_SMC_BASE 6 222 223 /* But this is what stacks really send out. */ 224 #define TCPOLEN_TSTAMP_ALIGNED 12 225 #define TCPOLEN_WSCALE_ALIGNED 4 226 #define TCPOLEN_SACKPERM_ALIGNED 4 227 #define TCPOLEN_SACK_BASE 2 228 #define TCPOLEN_SACK_BASE_ALIGNED 4 229 #define TCPOLEN_SACK_PERBLOCK 8 230 #define TCPOLEN_MD5SIG_ALIGNED 20 231 #define TCPOLEN_MSS_ALIGNED 4 232 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 233 234 /* Flags in tp->nonagle */ 235 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 236 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 237 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 238 239 /* TCP thin-stream limits */ 240 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 241 242 /* TCP initial congestion window as per rfc6928 */ 243 #define TCP_INIT_CWND 10 244 245 /* Bit Flags for sysctl_tcp_fastopen */ 246 #define TFO_CLIENT_ENABLE 1 247 #define TFO_SERVER_ENABLE 2 248 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 249 250 /* Accept SYN data w/o any cookie option */ 251 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 252 253 /* Force enable TFO on all listeners, i.e., not requiring the 254 * TCP_FASTOPEN socket option. 255 */ 256 #define TFO_SERVER_WO_SOCKOPT1 0x400 257 258 259 /* sysctl variables for tcp */ 260 extern int sysctl_tcp_max_orphans; 261 extern long sysctl_tcp_mem[3]; 262 263 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 264 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 265 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 266 267 extern atomic_long_t tcp_memory_allocated; 268 DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); 269 270 extern struct percpu_counter tcp_sockets_allocated; 271 extern unsigned long tcp_memory_pressure; 272 273 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 274 static inline bool tcp_under_memory_pressure(const struct sock *sk) 275 { 276 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 277 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 278 return true; 279 280 return READ_ONCE(tcp_memory_pressure); 281 } 282 /* 283 * The next routines deal with comparing 32 bit unsigned ints 284 * and worry about wraparound (automatic with unsigned arithmetic). 285 */ 286 287 static inline bool before(__u32 seq1, __u32 seq2) 288 { 289 return (__s32)(seq1-seq2) < 0; 290 } 291 #define after(seq2, seq1) before(seq1, seq2) 292 293 /* is s2<=s1<=s3 ? */ 294 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 295 { 296 return seq3 - seq2 >= seq1 - seq2; 297 } 298 299 static inline bool tcp_out_of_memory(struct sock *sk) 300 { 301 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 302 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 303 return true; 304 return false; 305 } 306 307 static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb) 308 { 309 sk_wmem_queued_add(sk, -skb->truesize); 310 if (!skb_zcopy_pure(skb)) 311 sk_mem_uncharge(sk, skb->truesize); 312 else 313 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb))); 314 __kfree_skb(skb); 315 } 316 317 void sk_forced_mem_schedule(struct sock *sk, int size); 318 319 bool tcp_check_oom(struct sock *sk, int shift); 320 321 322 extern struct proto tcp_prot; 323 324 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 325 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 326 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 327 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 328 329 void tcp_tasklet_init(void); 330 331 int tcp_v4_err(struct sk_buff *skb, u32); 332 333 void tcp_shutdown(struct sock *sk, int how); 334 335 int tcp_v4_early_demux(struct sk_buff *skb); 336 int tcp_v4_rcv(struct sk_buff *skb); 337 338 void tcp_remove_empty_skb(struct sock *sk); 339 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 340 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 341 int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, 342 size_t size, struct ubuf_info *uarg); 343 void tcp_splice_eof(struct socket *sock); 344 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 345 int tcp_wmem_schedule(struct sock *sk, int copy); 346 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 347 int size_goal); 348 void tcp_release_cb(struct sock *sk); 349 void tcp_wfree(struct sk_buff *skb); 350 void tcp_write_timer_handler(struct sock *sk); 351 void tcp_delack_timer_handler(struct sock *sk); 352 int tcp_ioctl(struct sock *sk, int cmd, int *karg); 353 enum skb_drop_reason tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 354 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 355 void tcp_rcv_space_adjust(struct sock *sk); 356 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 357 void tcp_twsk_destructor(struct sock *sk); 358 void tcp_twsk_purge(struct list_head *net_exit_list); 359 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 360 struct pipe_inode_info *pipe, size_t len, 361 unsigned int flags); 362 struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp, 363 bool force_schedule); 364 365 static inline void tcp_dec_quickack_mode(struct sock *sk) 366 { 367 struct inet_connection_sock *icsk = inet_csk(sk); 368 369 if (icsk->icsk_ack.quick) { 370 /* How many ACKs S/ACKing new data have we sent? */ 371 const unsigned int pkts = inet_csk_ack_scheduled(sk) ? 1 : 0; 372 373 if (pkts >= icsk->icsk_ack.quick) { 374 icsk->icsk_ack.quick = 0; 375 /* Leaving quickack mode we deflate ATO. */ 376 icsk->icsk_ack.ato = TCP_ATO_MIN; 377 } else 378 icsk->icsk_ack.quick -= pkts; 379 } 380 } 381 382 #define TCP_ECN_OK 1 383 #define TCP_ECN_QUEUE_CWR 2 384 #define TCP_ECN_DEMAND_CWR 4 385 #define TCP_ECN_SEEN 8 386 387 enum tcp_tw_status { 388 TCP_TW_SUCCESS = 0, 389 TCP_TW_RST = 1, 390 TCP_TW_ACK = 2, 391 TCP_TW_SYN = 3 392 }; 393 394 395 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 396 struct sk_buff *skb, 397 const struct tcphdr *th, 398 u32 *tw_isn); 399 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 400 struct request_sock *req, bool fastopen, 401 bool *lost_race); 402 enum skb_drop_reason tcp_child_process(struct sock *parent, struct sock *child, 403 struct sk_buff *skb); 404 void tcp_enter_loss(struct sock *sk); 405 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag); 406 void tcp_clear_retrans(struct tcp_sock *tp); 407 void tcp_update_metrics(struct sock *sk); 408 void tcp_init_metrics(struct sock *sk); 409 void tcp_metrics_init(void); 410 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 411 void __tcp_close(struct sock *sk, long timeout); 412 void tcp_close(struct sock *sk, long timeout); 413 void tcp_init_sock(struct sock *sk); 414 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb); 415 __poll_t tcp_poll(struct file *file, struct socket *sock, 416 struct poll_table_struct *wait); 417 int do_tcp_getsockopt(struct sock *sk, int level, 418 int optname, sockptr_t optval, sockptr_t optlen); 419 int tcp_getsockopt(struct sock *sk, int level, int optname, 420 char __user *optval, int __user *optlen); 421 bool tcp_bpf_bypass_getsockopt(int level, int optname); 422 int do_tcp_setsockopt(struct sock *sk, int level, int optname, 423 sockptr_t optval, unsigned int optlen); 424 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 425 unsigned int optlen); 426 void tcp_set_keepalive(struct sock *sk, int val); 427 void tcp_syn_ack_timeout(const struct request_sock *req); 428 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 429 int flags, int *addr_len); 430 int tcp_set_rcvlowat(struct sock *sk, int val); 431 int tcp_set_window_clamp(struct sock *sk, int val); 432 void tcp_update_recv_tstamps(struct sk_buff *skb, 433 struct scm_timestamping_internal *tss); 434 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, 435 struct scm_timestamping_internal *tss); 436 void tcp_data_ready(struct sock *sk); 437 #ifdef CONFIG_MMU 438 int tcp_mmap(struct file *file, struct socket *sock, 439 struct vm_area_struct *vma); 440 #endif 441 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 442 struct tcp_options_received *opt_rx, 443 int estab, struct tcp_fastopen_cookie *foc); 444 445 /* 446 * BPF SKB-less helpers 447 */ 448 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 449 struct tcphdr *th, u32 *cookie); 450 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 451 struct tcphdr *th, u32 *cookie); 452 u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss); 453 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 454 const struct tcp_request_sock_ops *af_ops, 455 struct sock *sk, struct tcphdr *th); 456 /* 457 * TCP v4 functions exported for the inet6 API 458 */ 459 460 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 461 void tcp_v4_mtu_reduced(struct sock *sk); 462 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 463 void tcp_ld_RTO_revert(struct sock *sk, u32 seq); 464 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 465 struct sock *tcp_create_openreq_child(const struct sock *sk, 466 struct request_sock *req, 467 struct sk_buff *skb); 468 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 469 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 470 struct request_sock *req, 471 struct dst_entry *dst, 472 struct request_sock *req_unhash, 473 bool *own_req); 474 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 475 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 476 int tcp_connect(struct sock *sk); 477 enum tcp_synack_type { 478 TCP_SYNACK_NORMAL, 479 TCP_SYNACK_FASTOPEN, 480 TCP_SYNACK_COOKIE, 481 }; 482 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 483 struct request_sock *req, 484 struct tcp_fastopen_cookie *foc, 485 enum tcp_synack_type synack_type, 486 struct sk_buff *syn_skb); 487 int tcp_disconnect(struct sock *sk, int flags); 488 489 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 490 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 491 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 492 493 /* From syncookies.c */ 494 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 495 struct request_sock *req, 496 struct dst_entry *dst); 497 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th); 498 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 499 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops, 500 struct sock *sk, struct sk_buff *skb, 501 struct tcp_options_received *tcp_opt, 502 int mss, u32 tsoff); 503 504 #if IS_ENABLED(CONFIG_BPF) 505 struct bpf_tcp_req_attrs { 506 u32 rcv_tsval; 507 u32 rcv_tsecr; 508 u16 mss; 509 u8 rcv_wscale; 510 u8 snd_wscale; 511 u8 ecn_ok; 512 u8 wscale_ok; 513 u8 sack_ok; 514 u8 tstamp_ok; 515 u8 usec_ts_ok; 516 u8 reserved[3]; 517 }; 518 #endif 519 520 #ifdef CONFIG_SYN_COOKIES 521 522 /* Syncookies use a monotonic timer which increments every 60 seconds. 523 * This counter is used both as a hash input and partially encoded into 524 * the cookie value. A cookie is only validated further if the delta 525 * between the current counter value and the encoded one is less than this, 526 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 527 * the counter advances immediately after a cookie is generated). 528 */ 529 #define MAX_SYNCOOKIE_AGE 2 530 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 531 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 532 533 /* syncookies: remember time of last synqueue overflow 534 * But do not dirty this field too often (once per second is enough) 535 * It is racy as we do not hold a lock, but race is very minor. 536 */ 537 static inline void tcp_synq_overflow(const struct sock *sk) 538 { 539 unsigned int last_overflow; 540 unsigned int now = jiffies; 541 542 if (sk->sk_reuseport) { 543 struct sock_reuseport *reuse; 544 545 reuse = rcu_dereference(sk->sk_reuseport_cb); 546 if (likely(reuse)) { 547 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 548 if (!time_between32(now, last_overflow, 549 last_overflow + HZ)) 550 WRITE_ONCE(reuse->synq_overflow_ts, now); 551 return; 552 } 553 } 554 555 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 556 if (!time_between32(now, last_overflow, last_overflow + HZ)) 557 WRITE_ONCE(tcp_sk_rw(sk)->rx_opt.ts_recent_stamp, now); 558 } 559 560 /* syncookies: no recent synqueue overflow on this listening socket? */ 561 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 562 { 563 unsigned int last_overflow; 564 unsigned int now = jiffies; 565 566 if (sk->sk_reuseport) { 567 struct sock_reuseport *reuse; 568 569 reuse = rcu_dereference(sk->sk_reuseport_cb); 570 if (likely(reuse)) { 571 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 572 return !time_between32(now, last_overflow - HZ, 573 last_overflow + 574 TCP_SYNCOOKIE_VALID); 575 } 576 } 577 578 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 579 580 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 581 * then we're under synflood. However, we have to use 582 * 'last_overflow - HZ' as lower bound. That's because a concurrent 583 * tcp_synq_overflow() could update .ts_recent_stamp after we read 584 * jiffies but before we store .ts_recent_stamp into last_overflow, 585 * which could lead to rejecting a valid syncookie. 586 */ 587 return !time_between32(now, last_overflow - HZ, 588 last_overflow + TCP_SYNCOOKIE_VALID); 589 } 590 591 static inline u32 tcp_cookie_time(void) 592 { 593 u64 val = get_jiffies_64(); 594 595 do_div(val, TCP_SYNCOOKIE_PERIOD); 596 return val; 597 } 598 599 /* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */ 600 static inline u64 tcp_ns_to_ts(bool usec_ts, u64 val) 601 { 602 if (usec_ts) 603 return div_u64(val, NSEC_PER_USEC); 604 605 return div_u64(val, NSEC_PER_MSEC); 606 } 607 608 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 609 u16 *mssp); 610 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 611 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 612 bool cookie_timestamp_decode(const struct net *net, 613 struct tcp_options_received *opt); 614 615 static inline bool cookie_ecn_ok(const struct net *net, const struct dst_entry *dst) 616 { 617 return READ_ONCE(net->ipv4.sysctl_tcp_ecn) || 618 dst_feature(dst, RTAX_FEATURE_ECN); 619 } 620 621 #if IS_ENABLED(CONFIG_BPF) 622 static inline bool cookie_bpf_ok(struct sk_buff *skb) 623 { 624 return skb->sk; 625 } 626 627 struct request_sock *cookie_bpf_check(struct sock *sk, struct sk_buff *skb); 628 #else 629 static inline bool cookie_bpf_ok(struct sk_buff *skb) 630 { 631 return false; 632 } 633 634 static inline struct request_sock *cookie_bpf_check(struct net *net, struct sock *sk, 635 struct sk_buff *skb) 636 { 637 return NULL; 638 } 639 #endif 640 641 /* From net/ipv6/syncookies.c */ 642 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th); 643 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 644 645 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 646 const struct tcphdr *th, u16 *mssp); 647 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 648 #endif 649 /* tcp_output.c */ 650 651 void tcp_skb_entail(struct sock *sk, struct sk_buff *skb); 652 void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb); 653 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 654 int nonagle); 655 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 656 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 657 void tcp_retransmit_timer(struct sock *sk); 658 void tcp_xmit_retransmit_queue(struct sock *); 659 void tcp_simple_retransmit(struct sock *); 660 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 661 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 662 enum tcp_queue { 663 TCP_FRAG_IN_WRITE_QUEUE, 664 TCP_FRAG_IN_RTX_QUEUE, 665 }; 666 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 667 struct sk_buff *skb, u32 len, 668 unsigned int mss_now, gfp_t gfp); 669 670 void tcp_send_probe0(struct sock *); 671 int tcp_write_wakeup(struct sock *, int mib); 672 void tcp_send_fin(struct sock *sk); 673 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 674 int tcp_send_synack(struct sock *); 675 void tcp_push_one(struct sock *, unsigned int mss_now); 676 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 677 void tcp_send_ack(struct sock *sk); 678 void tcp_send_delayed_ack(struct sock *sk); 679 void tcp_send_loss_probe(struct sock *sk); 680 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 681 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 682 const struct sk_buff *next_skb); 683 684 /* tcp_input.c */ 685 void tcp_rearm_rto(struct sock *sk); 686 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 687 void tcp_reset(struct sock *sk, struct sk_buff *skb); 688 void tcp_fin(struct sock *sk); 689 void tcp_check_space(struct sock *sk); 690 void tcp_sack_compress_send_ack(struct sock *sk); 691 692 /* tcp_timer.c */ 693 void tcp_init_xmit_timers(struct sock *); 694 static inline void tcp_clear_xmit_timers(struct sock *sk) 695 { 696 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 697 __sock_put(sk); 698 699 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 700 __sock_put(sk); 701 702 inet_csk_clear_xmit_timers(sk); 703 } 704 705 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 706 unsigned int tcp_current_mss(struct sock *sk); 707 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 708 709 /* Bound MSS / TSO packet size with the half of the window */ 710 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 711 { 712 int cutoff; 713 714 /* When peer uses tiny windows, there is no use in packetizing 715 * to sub-MSS pieces for the sake of SWS or making sure there 716 * are enough packets in the pipe for fast recovery. 717 * 718 * On the other hand, for extremely large MSS devices, handling 719 * smaller than MSS windows in this way does make sense. 720 */ 721 if (tp->max_window > TCP_MSS_DEFAULT) 722 cutoff = (tp->max_window >> 1); 723 else 724 cutoff = tp->max_window; 725 726 if (cutoff && pktsize > cutoff) 727 return max_t(int, cutoff, 68U - tp->tcp_header_len); 728 else 729 return pktsize; 730 } 731 732 /* tcp.c */ 733 void tcp_get_info(struct sock *, struct tcp_info *); 734 735 /* Read 'sendfile()'-style from a TCP socket */ 736 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 737 sk_read_actor_t recv_actor); 738 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 739 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off); 740 void tcp_read_done(struct sock *sk, size_t len); 741 742 void tcp_initialize_rcv_mss(struct sock *sk); 743 744 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 745 int tcp_mss_to_mtu(struct sock *sk, int mss); 746 void tcp_mtup_init(struct sock *sk); 747 748 static inline void tcp_bound_rto(struct sock *sk) 749 { 750 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 751 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 752 } 753 754 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 755 { 756 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 757 } 758 759 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 760 { 761 /* mptcp hooks are only on the slow path */ 762 if (sk_is_mptcp((struct sock *)tp)) 763 return; 764 765 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 766 ntohl(TCP_FLAG_ACK) | 767 snd_wnd); 768 } 769 770 static inline void tcp_fast_path_on(struct tcp_sock *tp) 771 { 772 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 773 } 774 775 static inline void tcp_fast_path_check(struct sock *sk) 776 { 777 struct tcp_sock *tp = tcp_sk(sk); 778 779 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 780 tp->rcv_wnd && 781 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 782 !tp->urg_data) 783 tcp_fast_path_on(tp); 784 } 785 786 u32 tcp_delack_max(const struct sock *sk); 787 788 /* Compute the actual rto_min value */ 789 static inline u32 tcp_rto_min(const struct sock *sk) 790 { 791 const struct dst_entry *dst = __sk_dst_get(sk); 792 u32 rto_min = inet_csk(sk)->icsk_rto_min; 793 794 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 795 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 796 return rto_min; 797 } 798 799 static inline u32 tcp_rto_min_us(const struct sock *sk) 800 { 801 return jiffies_to_usecs(tcp_rto_min(sk)); 802 } 803 804 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 805 { 806 return dst_metric_locked(dst, RTAX_CC_ALGO); 807 } 808 809 /* Minimum RTT in usec. ~0 means not available. */ 810 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 811 { 812 return minmax_get(&tp->rtt_min); 813 } 814 815 /* Compute the actual receive window we are currently advertising. 816 * Rcv_nxt can be after the window if our peer push more data 817 * than the offered window. 818 */ 819 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 820 { 821 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 822 823 if (win < 0) 824 win = 0; 825 return (u32) win; 826 } 827 828 /* Choose a new window, without checks for shrinking, and without 829 * scaling applied to the result. The caller does these things 830 * if necessary. This is a "raw" window selection. 831 */ 832 u32 __tcp_select_window(struct sock *sk); 833 834 void tcp_send_window_probe(struct sock *sk); 835 836 /* TCP uses 32bit jiffies to save some space. 837 * Note that this is different from tcp_time_stamp, which 838 * historically has been the same until linux-4.13. 839 */ 840 #define tcp_jiffies32 ((u32)jiffies) 841 842 /* 843 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 844 * It is no longer tied to jiffies, but to 1 ms clock. 845 * Note: double check if you want to use tcp_jiffies32 instead of this. 846 */ 847 #define TCP_TS_HZ 1000 848 849 static inline u64 tcp_clock_ns(void) 850 { 851 return ktime_get_ns(); 852 } 853 854 static inline u64 tcp_clock_us(void) 855 { 856 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 857 } 858 859 static inline u64 tcp_clock_ms(void) 860 { 861 return div_u64(tcp_clock_ns(), NSEC_PER_MSEC); 862 } 863 864 /* TCP Timestamp included in TS option (RFC 1323) can either use ms 865 * or usec resolution. Each socket carries a flag to select one or other 866 * resolution, as the route attribute could change anytime. 867 * Each flow must stick to initial resolution. 868 */ 869 static inline u32 tcp_clock_ts(bool usec_ts) 870 { 871 return usec_ts ? tcp_clock_us() : tcp_clock_ms(); 872 } 873 874 static inline u32 tcp_time_stamp_ms(const struct tcp_sock *tp) 875 { 876 return div_u64(tp->tcp_mstamp, USEC_PER_MSEC); 877 } 878 879 static inline u32 tcp_time_stamp_ts(const struct tcp_sock *tp) 880 { 881 if (tp->tcp_usec_ts) 882 return tp->tcp_mstamp; 883 return tcp_time_stamp_ms(tp); 884 } 885 886 void tcp_mstamp_refresh(struct tcp_sock *tp); 887 888 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 889 { 890 return max_t(s64, t1 - t0, 0); 891 } 892 893 /* provide the departure time in us unit */ 894 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 895 { 896 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 897 } 898 899 /* Provide skb TSval in usec or ms unit */ 900 static inline u32 tcp_skb_timestamp_ts(bool usec_ts, const struct sk_buff *skb) 901 { 902 if (usec_ts) 903 return tcp_skb_timestamp_us(skb); 904 905 return div_u64(skb->skb_mstamp_ns, NSEC_PER_MSEC); 906 } 907 908 static inline u32 tcp_tw_tsval(const struct tcp_timewait_sock *tcptw) 909 { 910 return tcp_clock_ts(tcptw->tw_sk.tw_usec_ts) + tcptw->tw_ts_offset; 911 } 912 913 static inline u32 tcp_rsk_tsval(const struct tcp_request_sock *treq) 914 { 915 return tcp_clock_ts(treq->req_usec_ts) + treq->ts_off; 916 } 917 918 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 919 920 #define TCPHDR_FIN 0x01 921 #define TCPHDR_SYN 0x02 922 #define TCPHDR_RST 0x04 923 #define TCPHDR_PSH 0x08 924 #define TCPHDR_ACK 0x10 925 #define TCPHDR_URG 0x20 926 #define TCPHDR_ECE 0x40 927 #define TCPHDR_CWR 0x80 928 929 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 930 931 /* This is what the send packet queuing engine uses to pass 932 * TCP per-packet control information to the transmission code. 933 * We also store the host-order sequence numbers in here too. 934 * This is 44 bytes if IPV6 is enabled. 935 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 936 */ 937 struct tcp_skb_cb { 938 __u32 seq; /* Starting sequence number */ 939 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 940 union { 941 /* Note : 942 * tcp_gso_segs/size are used in write queue only, 943 * cf tcp_skb_pcount()/tcp_skb_mss() 944 */ 945 struct { 946 u16 tcp_gso_segs; 947 u16 tcp_gso_size; 948 }; 949 }; 950 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 951 952 __u8 sacked; /* State flags for SACK. */ 953 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 954 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 955 #define TCPCB_LOST 0x04 /* SKB is lost */ 956 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 957 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 958 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 959 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 960 TCPCB_REPAIRED) 961 962 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 963 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 964 eor:1, /* Is skb MSG_EOR marked? */ 965 has_rxtstamp:1, /* SKB has a RX timestamp */ 966 unused:5; 967 __u32 ack_seq; /* Sequence number ACK'd */ 968 union { 969 struct { 970 #define TCPCB_DELIVERED_CE_MASK ((1U<<20) - 1) 971 /* There is space for up to 24 bytes */ 972 __u32 is_app_limited:1, /* cwnd not fully used? */ 973 delivered_ce:20, 974 unused:11; 975 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 976 __u32 delivered; 977 /* start of send pipeline phase */ 978 u64 first_tx_mstamp; 979 /* when we reached the "delivered" count */ 980 u64 delivered_mstamp; 981 } tx; /* only used for outgoing skbs */ 982 union { 983 struct inet_skb_parm h4; 984 #if IS_ENABLED(CONFIG_IPV6) 985 struct inet6_skb_parm h6; 986 #endif 987 } header; /* For incoming skbs */ 988 }; 989 }; 990 991 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 992 993 extern const struct inet_connection_sock_af_ops ipv4_specific; 994 995 #if IS_ENABLED(CONFIG_IPV6) 996 /* This is the variant of inet6_iif() that must be used by TCP, 997 * as TCP moves IP6CB into a different location in skb->cb[] 998 */ 999 static inline int tcp_v6_iif(const struct sk_buff *skb) 1000 { 1001 return TCP_SKB_CB(skb)->header.h6.iif; 1002 } 1003 1004 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 1005 { 1006 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 1007 1008 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 1009 } 1010 1011 /* TCP_SKB_CB reference means this can not be used from early demux */ 1012 static inline int tcp_v6_sdif(const struct sk_buff *skb) 1013 { 1014 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 1015 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 1016 return TCP_SKB_CB(skb)->header.h6.iif; 1017 #endif 1018 return 0; 1019 } 1020 1021 extern const struct inet_connection_sock_af_ops ipv6_specific; 1022 1023 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 1024 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 1025 void tcp_v6_early_demux(struct sk_buff *skb); 1026 1027 #endif 1028 1029 /* TCP_SKB_CB reference means this can not be used from early demux */ 1030 static inline int tcp_v4_sdif(struct sk_buff *skb) 1031 { 1032 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 1033 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 1034 return TCP_SKB_CB(skb)->header.h4.iif; 1035 #endif 1036 return 0; 1037 } 1038 1039 /* Due to TSO, an SKB can be composed of multiple actual 1040 * packets. To keep these tracked properly, we use this. 1041 */ 1042 static inline int tcp_skb_pcount(const struct sk_buff *skb) 1043 { 1044 return TCP_SKB_CB(skb)->tcp_gso_segs; 1045 } 1046 1047 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 1048 { 1049 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 1050 } 1051 1052 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 1053 { 1054 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 1055 } 1056 1057 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 1058 static inline int tcp_skb_mss(const struct sk_buff *skb) 1059 { 1060 return TCP_SKB_CB(skb)->tcp_gso_size; 1061 } 1062 1063 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 1064 { 1065 return likely(!TCP_SKB_CB(skb)->eor); 1066 } 1067 1068 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 1069 const struct sk_buff *from) 1070 { 1071 return likely(tcp_skb_can_collapse_to(to) && 1072 mptcp_skb_can_collapse(to, from) && 1073 skb_pure_zcopy_same(to, from)); 1074 } 1075 1076 /* Events passed to congestion control interface */ 1077 enum tcp_ca_event { 1078 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 1079 CA_EVENT_CWND_RESTART, /* congestion window restart */ 1080 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 1081 CA_EVENT_LOSS, /* loss timeout */ 1082 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 1083 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 1084 }; 1085 1086 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1087 enum tcp_ca_ack_event_flags { 1088 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1089 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1090 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1091 }; 1092 1093 /* 1094 * Interface for adding new TCP congestion control handlers 1095 */ 1096 #define TCP_CA_NAME_MAX 16 1097 #define TCP_CA_MAX 128 1098 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1099 1100 #define TCP_CA_UNSPEC 0 1101 1102 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1103 #define TCP_CONG_NON_RESTRICTED 0x1 1104 /* Requires ECN/ECT set on all packets */ 1105 #define TCP_CONG_NEEDS_ECN 0x2 1106 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1107 1108 union tcp_cc_info; 1109 1110 struct ack_sample { 1111 u32 pkts_acked; 1112 s32 rtt_us; 1113 u32 in_flight; 1114 }; 1115 1116 /* A rate sample measures the number of (original/retransmitted) data 1117 * packets delivered "delivered" over an interval of time "interval_us". 1118 * The tcp_rate.c code fills in the rate sample, and congestion 1119 * control modules that define a cong_control function to run at the end 1120 * of ACK processing can optionally chose to consult this sample when 1121 * setting cwnd and pacing rate. 1122 * A sample is invalid if "delivered" or "interval_us" is negative. 1123 */ 1124 struct rate_sample { 1125 u64 prior_mstamp; /* starting timestamp for interval */ 1126 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1127 u32 prior_delivered_ce;/* tp->delivered_ce at "prior_mstamp" */ 1128 s32 delivered; /* number of packets delivered over interval */ 1129 s32 delivered_ce; /* number of packets delivered w/ CE marks*/ 1130 long interval_us; /* time for tp->delivered to incr "delivered" */ 1131 u32 snd_interval_us; /* snd interval for delivered packets */ 1132 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1133 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1134 int losses; /* number of packets marked lost upon ACK */ 1135 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1136 u32 prior_in_flight; /* in flight before this ACK */ 1137 u32 last_end_seq; /* end_seq of most recently ACKed packet */ 1138 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1139 bool is_retrans; /* is sample from retransmission? */ 1140 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1141 }; 1142 1143 struct tcp_congestion_ops { 1144 /* fast path fields are put first to fill one cache line */ 1145 1146 /* return slow start threshold (required) */ 1147 u32 (*ssthresh)(struct sock *sk); 1148 1149 /* do new cwnd calculation (required) */ 1150 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1151 1152 /* call before changing ca_state (optional) */ 1153 void (*set_state)(struct sock *sk, u8 new_state); 1154 1155 /* call when cwnd event occurs (optional) */ 1156 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1157 1158 /* call when ack arrives (optional) */ 1159 void (*in_ack_event)(struct sock *sk, u32 flags); 1160 1161 /* hook for packet ack accounting (optional) */ 1162 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1163 1164 /* override sysctl_tcp_min_tso_segs */ 1165 u32 (*min_tso_segs)(struct sock *sk); 1166 1167 /* call when packets are delivered to update cwnd and pacing rate, 1168 * after all the ca_state processing. (optional) 1169 */ 1170 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1171 1172 1173 /* new value of cwnd after loss (required) */ 1174 u32 (*undo_cwnd)(struct sock *sk); 1175 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1176 u32 (*sndbuf_expand)(struct sock *sk); 1177 1178 /* control/slow paths put last */ 1179 /* get info for inet_diag (optional) */ 1180 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1181 union tcp_cc_info *info); 1182 1183 char name[TCP_CA_NAME_MAX]; 1184 struct module *owner; 1185 struct list_head list; 1186 u32 key; 1187 u32 flags; 1188 1189 /* initialize private data (optional) */ 1190 void (*init)(struct sock *sk); 1191 /* cleanup private data (optional) */ 1192 void (*release)(struct sock *sk); 1193 } ____cacheline_aligned_in_smp; 1194 1195 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1196 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1197 int tcp_update_congestion_control(struct tcp_congestion_ops *type, 1198 struct tcp_congestion_ops *old_type); 1199 int tcp_validate_congestion_control(struct tcp_congestion_ops *ca); 1200 1201 void tcp_assign_congestion_control(struct sock *sk); 1202 void tcp_init_congestion_control(struct sock *sk); 1203 void tcp_cleanup_congestion_control(struct sock *sk); 1204 int tcp_set_default_congestion_control(struct net *net, const char *name); 1205 void tcp_get_default_congestion_control(struct net *net, char *name); 1206 void tcp_get_available_congestion_control(char *buf, size_t len); 1207 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1208 int tcp_set_allowed_congestion_control(char *allowed); 1209 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1210 bool cap_net_admin); 1211 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1212 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1213 1214 u32 tcp_reno_ssthresh(struct sock *sk); 1215 u32 tcp_reno_undo_cwnd(struct sock *sk); 1216 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1217 extern struct tcp_congestion_ops tcp_reno; 1218 1219 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1220 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1221 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1222 #ifdef CONFIG_INET 1223 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1224 #else 1225 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1226 { 1227 return NULL; 1228 } 1229 #endif 1230 1231 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1232 { 1233 const struct inet_connection_sock *icsk = inet_csk(sk); 1234 1235 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1236 } 1237 1238 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1239 { 1240 const struct inet_connection_sock *icsk = inet_csk(sk); 1241 1242 if (icsk->icsk_ca_ops->cwnd_event) 1243 icsk->icsk_ca_ops->cwnd_event(sk, event); 1244 } 1245 1246 /* From tcp_cong.c */ 1247 void tcp_set_ca_state(struct sock *sk, const u8 ca_state); 1248 1249 /* From tcp_rate.c */ 1250 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1251 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1252 struct rate_sample *rs); 1253 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1254 bool is_sack_reneg, struct rate_sample *rs); 1255 void tcp_rate_check_app_limited(struct sock *sk); 1256 1257 static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2) 1258 { 1259 return t1 > t2 || (t1 == t2 && after(seq1, seq2)); 1260 } 1261 1262 /* These functions determine how the current flow behaves in respect of SACK 1263 * handling. SACK is negotiated with the peer, and therefore it can vary 1264 * between different flows. 1265 * 1266 * tcp_is_sack - SACK enabled 1267 * tcp_is_reno - No SACK 1268 */ 1269 static inline int tcp_is_sack(const struct tcp_sock *tp) 1270 { 1271 return likely(tp->rx_opt.sack_ok); 1272 } 1273 1274 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1275 { 1276 return !tcp_is_sack(tp); 1277 } 1278 1279 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1280 { 1281 return tp->sacked_out + tp->lost_out; 1282 } 1283 1284 /* This determines how many packets are "in the network" to the best 1285 * of our knowledge. In many cases it is conservative, but where 1286 * detailed information is available from the receiver (via SACK 1287 * blocks etc.) we can make more aggressive calculations. 1288 * 1289 * Use this for decisions involving congestion control, use just 1290 * tp->packets_out to determine if the send queue is empty or not. 1291 * 1292 * Read this equation as: 1293 * 1294 * "Packets sent once on transmission queue" MINUS 1295 * "Packets left network, but not honestly ACKed yet" PLUS 1296 * "Packets fast retransmitted" 1297 */ 1298 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1299 { 1300 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1301 } 1302 1303 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1304 1305 static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp) 1306 { 1307 return tp->snd_cwnd; 1308 } 1309 1310 static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val) 1311 { 1312 WARN_ON_ONCE((int)val <= 0); 1313 tp->snd_cwnd = val; 1314 } 1315 1316 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1317 { 1318 return tcp_snd_cwnd(tp) < tp->snd_ssthresh; 1319 } 1320 1321 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1322 { 1323 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1324 } 1325 1326 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1327 { 1328 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1329 (1 << inet_csk(sk)->icsk_ca_state); 1330 } 1331 1332 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1333 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1334 * ssthresh. 1335 */ 1336 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1337 { 1338 const struct tcp_sock *tp = tcp_sk(sk); 1339 1340 if (tcp_in_cwnd_reduction(sk)) 1341 return tp->snd_ssthresh; 1342 else 1343 return max(tp->snd_ssthresh, 1344 ((tcp_snd_cwnd(tp) >> 1) + 1345 (tcp_snd_cwnd(tp) >> 2))); 1346 } 1347 1348 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1349 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1350 1351 void tcp_enter_cwr(struct sock *sk); 1352 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1353 1354 /* The maximum number of MSS of available cwnd for which TSO defers 1355 * sending if not using sysctl_tcp_tso_win_divisor. 1356 */ 1357 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1358 { 1359 return 3; 1360 } 1361 1362 /* Returns end sequence number of the receiver's advertised window */ 1363 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1364 { 1365 return tp->snd_una + tp->snd_wnd; 1366 } 1367 1368 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1369 * flexible approach. The RFC suggests cwnd should not be raised unless 1370 * it was fully used previously. And that's exactly what we do in 1371 * congestion avoidance mode. But in slow start we allow cwnd to grow 1372 * as long as the application has used half the cwnd. 1373 * Example : 1374 * cwnd is 10 (IW10), but application sends 9 frames. 1375 * We allow cwnd to reach 18 when all frames are ACKed. 1376 * This check is safe because it's as aggressive as slow start which already 1377 * risks 100% overshoot. The advantage is that we discourage application to 1378 * either send more filler packets or data to artificially blow up the cwnd 1379 * usage, and allow application-limited process to probe bw more aggressively. 1380 */ 1381 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1382 { 1383 const struct tcp_sock *tp = tcp_sk(sk); 1384 1385 if (tp->is_cwnd_limited) 1386 return true; 1387 1388 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1389 if (tcp_in_slow_start(tp)) 1390 return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out; 1391 1392 return false; 1393 } 1394 1395 /* BBR congestion control needs pacing. 1396 * Same remark for SO_MAX_PACING_RATE. 1397 * sch_fq packet scheduler is efficiently handling pacing, 1398 * but is not always installed/used. 1399 * Return true if TCP stack should pace packets itself. 1400 */ 1401 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1402 { 1403 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1404 } 1405 1406 /* Estimates in how many jiffies next packet for this flow can be sent. 1407 * Scheduling a retransmit timer too early would be silly. 1408 */ 1409 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1410 { 1411 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1412 1413 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1414 } 1415 1416 static inline void tcp_reset_xmit_timer(struct sock *sk, 1417 const int what, 1418 unsigned long when, 1419 const unsigned long max_when) 1420 { 1421 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk), 1422 max_when); 1423 } 1424 1425 /* Something is really bad, we could not queue an additional packet, 1426 * because qdisc is full or receiver sent a 0 window, or we are paced. 1427 * We do not want to add fuel to the fire, or abort too early, 1428 * so make sure the timer we arm now is at least 200ms in the future, 1429 * regardless of current icsk_rto value (as it could be ~2ms) 1430 */ 1431 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1432 { 1433 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1434 } 1435 1436 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1437 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1438 unsigned long max_when) 1439 { 1440 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1441 inet_csk(sk)->icsk_backoff); 1442 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1443 1444 return (unsigned long)min_t(u64, when, max_when); 1445 } 1446 1447 static inline void tcp_check_probe_timer(struct sock *sk) 1448 { 1449 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1450 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1451 tcp_probe0_base(sk), TCP_RTO_MAX); 1452 } 1453 1454 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1455 { 1456 tp->snd_wl1 = seq; 1457 } 1458 1459 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1460 { 1461 tp->snd_wl1 = seq; 1462 } 1463 1464 /* 1465 * Calculate(/check) TCP checksum 1466 */ 1467 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1468 __be32 daddr, __wsum base) 1469 { 1470 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1471 } 1472 1473 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1474 { 1475 return !skb_csum_unnecessary(skb) && 1476 __skb_checksum_complete(skb); 1477 } 1478 1479 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1480 enum skb_drop_reason *reason); 1481 1482 1483 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1484 void tcp_set_state(struct sock *sk, int state); 1485 void tcp_done(struct sock *sk); 1486 int tcp_abort(struct sock *sk, int err); 1487 1488 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1489 { 1490 rx_opt->dsack = 0; 1491 rx_opt->num_sacks = 0; 1492 } 1493 1494 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1495 1496 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1497 { 1498 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1499 struct tcp_sock *tp = tcp_sk(sk); 1500 s32 delta; 1501 1502 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) || 1503 tp->packets_out || ca_ops->cong_control) 1504 return; 1505 delta = tcp_jiffies32 - tp->lsndtime; 1506 if (delta > inet_csk(sk)->icsk_rto) 1507 tcp_cwnd_restart(sk, delta); 1508 } 1509 1510 /* Determine a window scaling and initial window to offer. */ 1511 void tcp_select_initial_window(const struct sock *sk, int __space, 1512 __u32 mss, __u32 *rcv_wnd, 1513 __u32 *window_clamp, int wscale_ok, 1514 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1515 1516 static inline int __tcp_win_from_space(u8 scaling_ratio, int space) 1517 { 1518 s64 scaled_space = (s64)space * scaling_ratio; 1519 1520 return scaled_space >> TCP_RMEM_TO_WIN_SCALE; 1521 } 1522 1523 static inline int tcp_win_from_space(const struct sock *sk, int space) 1524 { 1525 return __tcp_win_from_space(tcp_sk(sk)->scaling_ratio, space); 1526 } 1527 1528 /* inverse of __tcp_win_from_space() */ 1529 static inline int __tcp_space_from_win(u8 scaling_ratio, int win) 1530 { 1531 u64 val = (u64)win << TCP_RMEM_TO_WIN_SCALE; 1532 1533 do_div(val, scaling_ratio); 1534 return val; 1535 } 1536 1537 static inline int tcp_space_from_win(const struct sock *sk, int win) 1538 { 1539 return __tcp_space_from_win(tcp_sk(sk)->scaling_ratio, win); 1540 } 1541 1542 /* Assume a conservative default of 1200 bytes of payload per 4K page. 1543 * This may be adjusted later in tcp_measure_rcv_mss(). 1544 */ 1545 #define TCP_DEFAULT_SCALING_RATIO ((1200 << TCP_RMEM_TO_WIN_SCALE) / \ 1546 SKB_TRUESIZE(4096)) 1547 1548 static inline void tcp_scaling_ratio_init(struct sock *sk) 1549 { 1550 tcp_sk(sk)->scaling_ratio = TCP_DEFAULT_SCALING_RATIO; 1551 } 1552 1553 /* Note: caller must be prepared to deal with negative returns */ 1554 static inline int tcp_space(const struct sock *sk) 1555 { 1556 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1557 READ_ONCE(sk->sk_backlog.len) - 1558 atomic_read(&sk->sk_rmem_alloc)); 1559 } 1560 1561 static inline int tcp_full_space(const struct sock *sk) 1562 { 1563 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1564 } 1565 1566 static inline void __tcp_adjust_rcv_ssthresh(struct sock *sk, u32 new_ssthresh) 1567 { 1568 int unused_mem = sk_unused_reserved_mem(sk); 1569 struct tcp_sock *tp = tcp_sk(sk); 1570 1571 tp->rcv_ssthresh = min(tp->rcv_ssthresh, new_ssthresh); 1572 if (unused_mem) 1573 tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh, 1574 tcp_win_from_space(sk, unused_mem)); 1575 } 1576 1577 static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) 1578 { 1579 __tcp_adjust_rcv_ssthresh(sk, 4U * tcp_sk(sk)->advmss); 1580 } 1581 1582 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1583 void __tcp_cleanup_rbuf(struct sock *sk, int copied); 1584 1585 1586 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1587 * If 87.5 % (7/8) of the space has been consumed, we want to override 1588 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1589 * len/truesize ratio. 1590 */ 1591 static inline bool tcp_rmem_pressure(const struct sock *sk) 1592 { 1593 int rcvbuf, threshold; 1594 1595 if (tcp_under_memory_pressure(sk)) 1596 return true; 1597 1598 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1599 threshold = rcvbuf - (rcvbuf >> 3); 1600 1601 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1602 } 1603 1604 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1605 { 1606 const struct tcp_sock *tp = tcp_sk(sk); 1607 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1608 1609 if (avail <= 0) 1610 return false; 1611 1612 return (avail >= target) || tcp_rmem_pressure(sk) || 1613 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1614 } 1615 1616 extern void tcp_openreq_init_rwin(struct request_sock *req, 1617 const struct sock *sk_listener, 1618 const struct dst_entry *dst); 1619 1620 void tcp_enter_memory_pressure(struct sock *sk); 1621 void tcp_leave_memory_pressure(struct sock *sk); 1622 1623 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1624 { 1625 struct net *net = sock_net((struct sock *)tp); 1626 int val; 1627 1628 /* Paired with WRITE_ONCE() in tcp_sock_set_keepintvl() 1629 * and do_tcp_setsockopt(). 1630 */ 1631 val = READ_ONCE(tp->keepalive_intvl); 1632 1633 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); 1634 } 1635 1636 static inline int keepalive_time_when(const struct tcp_sock *tp) 1637 { 1638 struct net *net = sock_net((struct sock *)tp); 1639 int val; 1640 1641 /* Paired with WRITE_ONCE() in tcp_sock_set_keepidle_locked() */ 1642 val = READ_ONCE(tp->keepalive_time); 1643 1644 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); 1645 } 1646 1647 static inline int keepalive_probes(const struct tcp_sock *tp) 1648 { 1649 struct net *net = sock_net((struct sock *)tp); 1650 int val; 1651 1652 /* Paired with WRITE_ONCE() in tcp_sock_set_keepcnt() 1653 * and do_tcp_setsockopt(). 1654 */ 1655 val = READ_ONCE(tp->keepalive_probes); 1656 1657 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); 1658 } 1659 1660 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1661 { 1662 const struct inet_connection_sock *icsk = &tp->inet_conn; 1663 1664 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1665 tcp_jiffies32 - tp->rcv_tstamp); 1666 } 1667 1668 static inline int tcp_fin_time(const struct sock *sk) 1669 { 1670 int fin_timeout = tcp_sk(sk)->linger2 ? : 1671 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); 1672 const int rto = inet_csk(sk)->icsk_rto; 1673 1674 if (fin_timeout < (rto << 2) - (rto >> 1)) 1675 fin_timeout = (rto << 2) - (rto >> 1); 1676 1677 return fin_timeout; 1678 } 1679 1680 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1681 int paws_win) 1682 { 1683 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1684 return true; 1685 if (unlikely(!time_before32(ktime_get_seconds(), 1686 rx_opt->ts_recent_stamp + TCP_PAWS_WRAP))) 1687 return true; 1688 /* 1689 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1690 * then following tcp messages have valid values. Ignore 0 value, 1691 * or else 'negative' tsval might forbid us to accept their packets. 1692 */ 1693 if (!rx_opt->ts_recent) 1694 return true; 1695 return false; 1696 } 1697 1698 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1699 int rst) 1700 { 1701 if (tcp_paws_check(rx_opt, 0)) 1702 return false; 1703 1704 /* RST segments are not recommended to carry timestamp, 1705 and, if they do, it is recommended to ignore PAWS because 1706 "their cleanup function should take precedence over timestamps." 1707 Certainly, it is mistake. It is necessary to understand the reasons 1708 of this constraint to relax it: if peer reboots, clock may go 1709 out-of-sync and half-open connections will not be reset. 1710 Actually, the problem would be not existing if all 1711 the implementations followed draft about maintaining clock 1712 via reboots. Linux-2.2 DOES NOT! 1713 1714 However, we can relax time bounds for RST segments to MSL. 1715 */ 1716 if (rst && !time_before32(ktime_get_seconds(), 1717 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1718 return false; 1719 return true; 1720 } 1721 1722 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1723 int mib_idx, u32 *last_oow_ack_time); 1724 1725 static inline void tcp_mib_init(struct net *net) 1726 { 1727 /* See RFC 2012 */ 1728 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1729 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1730 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1731 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1732 } 1733 1734 /* from STCP */ 1735 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1736 { 1737 tp->lost_skb_hint = NULL; 1738 } 1739 1740 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1741 { 1742 tcp_clear_retrans_hints_partial(tp); 1743 tp->retransmit_skb_hint = NULL; 1744 } 1745 1746 #define tcp_md5_addr tcp_ao_addr 1747 1748 /* - key database */ 1749 struct tcp_md5sig_key { 1750 struct hlist_node node; 1751 u8 keylen; 1752 u8 family; /* AF_INET or AF_INET6 */ 1753 u8 prefixlen; 1754 u8 flags; 1755 union tcp_md5_addr addr; 1756 int l3index; /* set if key added with L3 scope */ 1757 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1758 struct rcu_head rcu; 1759 }; 1760 1761 /* - sock block */ 1762 struct tcp_md5sig_info { 1763 struct hlist_head head; 1764 struct rcu_head rcu; 1765 }; 1766 1767 /* - pseudo header */ 1768 struct tcp4_pseudohdr { 1769 __be32 saddr; 1770 __be32 daddr; 1771 __u8 pad; 1772 __u8 protocol; 1773 __be16 len; 1774 }; 1775 1776 struct tcp6_pseudohdr { 1777 struct in6_addr saddr; 1778 struct in6_addr daddr; 1779 __be32 len; 1780 __be32 protocol; /* including padding */ 1781 }; 1782 1783 union tcp_md5sum_block { 1784 struct tcp4_pseudohdr ip4; 1785 #if IS_ENABLED(CONFIG_IPV6) 1786 struct tcp6_pseudohdr ip6; 1787 #endif 1788 }; 1789 1790 /* 1791 * struct tcp_sigpool - per-CPU pool of ahash_requests 1792 * @scratch: per-CPU temporary area, that can be used between 1793 * tcp_sigpool_start() and tcp_sigpool_end() to perform 1794 * crypto request 1795 * @req: pre-allocated ahash request 1796 */ 1797 struct tcp_sigpool { 1798 void *scratch; 1799 struct ahash_request *req; 1800 }; 1801 1802 int tcp_sigpool_alloc_ahash(const char *alg, size_t scratch_size); 1803 void tcp_sigpool_get(unsigned int id); 1804 void tcp_sigpool_release(unsigned int id); 1805 int tcp_sigpool_hash_skb_data(struct tcp_sigpool *hp, 1806 const struct sk_buff *skb, 1807 unsigned int header_len); 1808 1809 /** 1810 * tcp_sigpool_start - disable bh and start using tcp_sigpool_ahash 1811 * @id: tcp_sigpool that was previously allocated by tcp_sigpool_alloc_ahash() 1812 * @c: returned tcp_sigpool for usage (uninitialized on failure) 1813 * 1814 * Returns 0 on success, error otherwise. 1815 */ 1816 int tcp_sigpool_start(unsigned int id, struct tcp_sigpool *c); 1817 /** 1818 * tcp_sigpool_end - enable bh and stop using tcp_sigpool 1819 * @c: tcp_sigpool context that was returned by tcp_sigpool_start() 1820 */ 1821 void tcp_sigpool_end(struct tcp_sigpool *c); 1822 size_t tcp_sigpool_algo(unsigned int id, char *buf, size_t buf_len); 1823 /* - functions */ 1824 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1825 const struct sock *sk, const struct sk_buff *skb); 1826 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1827 int family, u8 prefixlen, int l3index, u8 flags, 1828 const u8 *newkey, u8 newkeylen); 1829 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1830 int family, u8 prefixlen, int l3index, 1831 struct tcp_md5sig_key *key); 1832 1833 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1834 int family, u8 prefixlen, int l3index, u8 flags); 1835 void tcp_clear_md5_list(struct sock *sk); 1836 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1837 const struct sock *addr_sk); 1838 1839 #ifdef CONFIG_TCP_MD5SIG 1840 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1841 const union tcp_md5_addr *addr, 1842 int family, bool any_l3index); 1843 static inline struct tcp_md5sig_key * 1844 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1845 const union tcp_md5_addr *addr, int family) 1846 { 1847 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1848 return NULL; 1849 return __tcp_md5_do_lookup(sk, l3index, addr, family, false); 1850 } 1851 1852 static inline struct tcp_md5sig_key * 1853 tcp_md5_do_lookup_any_l3index(const struct sock *sk, 1854 const union tcp_md5_addr *addr, int family) 1855 { 1856 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1857 return NULL; 1858 return __tcp_md5_do_lookup(sk, 0, addr, family, true); 1859 } 1860 1861 enum skb_drop_reason 1862 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1863 const void *saddr, const void *daddr, 1864 int family, int l3index, const __u8 *hash_location); 1865 1866 1867 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1868 #else 1869 static inline struct tcp_md5sig_key * 1870 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1871 const union tcp_md5_addr *addr, int family) 1872 { 1873 return NULL; 1874 } 1875 1876 static inline struct tcp_md5sig_key * 1877 tcp_md5_do_lookup_any_l3index(const struct sock *sk, 1878 const union tcp_md5_addr *addr, int family) 1879 { 1880 return NULL; 1881 } 1882 1883 static inline enum skb_drop_reason 1884 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1885 const void *saddr, const void *daddr, 1886 int family, int l3index, const __u8 *hash_location) 1887 { 1888 return SKB_NOT_DROPPED_YET; 1889 } 1890 #define tcp_twsk_md5_key(twsk) NULL 1891 #endif 1892 1893 int tcp_md5_alloc_sigpool(void); 1894 void tcp_md5_release_sigpool(void); 1895 void tcp_md5_add_sigpool(void); 1896 extern int tcp_md5_sigpool_id; 1897 1898 int tcp_md5_hash_key(struct tcp_sigpool *hp, 1899 const struct tcp_md5sig_key *key); 1900 1901 /* From tcp_fastopen.c */ 1902 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1903 struct tcp_fastopen_cookie *cookie); 1904 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1905 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1906 u16 try_exp); 1907 struct tcp_fastopen_request { 1908 /* Fast Open cookie. Size 0 means a cookie request */ 1909 struct tcp_fastopen_cookie cookie; 1910 struct msghdr *data; /* data in MSG_FASTOPEN */ 1911 size_t size; 1912 int copied; /* queued in tcp_connect() */ 1913 struct ubuf_info *uarg; 1914 }; 1915 void tcp_free_fastopen_req(struct tcp_sock *tp); 1916 void tcp_fastopen_destroy_cipher(struct sock *sk); 1917 void tcp_fastopen_ctx_destroy(struct net *net); 1918 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1919 void *primary_key, void *backup_key); 1920 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1921 u64 *key); 1922 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1923 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1924 struct request_sock *req, 1925 struct tcp_fastopen_cookie *foc, 1926 const struct dst_entry *dst); 1927 void tcp_fastopen_init_key_once(struct net *net); 1928 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1929 struct tcp_fastopen_cookie *cookie); 1930 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1931 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1932 #define TCP_FASTOPEN_KEY_MAX 2 1933 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1934 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1935 1936 /* Fastopen key context */ 1937 struct tcp_fastopen_context { 1938 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1939 int num; 1940 struct rcu_head rcu; 1941 }; 1942 1943 void tcp_fastopen_active_disable(struct sock *sk); 1944 bool tcp_fastopen_active_should_disable(struct sock *sk); 1945 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1946 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1947 1948 /* Caller needs to wrap with rcu_read_(un)lock() */ 1949 static inline 1950 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1951 { 1952 struct tcp_fastopen_context *ctx; 1953 1954 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1955 if (!ctx) 1956 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1957 return ctx; 1958 } 1959 1960 static inline 1961 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1962 const struct tcp_fastopen_cookie *orig) 1963 { 1964 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1965 orig->len == foc->len && 1966 !memcmp(orig->val, foc->val, foc->len)) 1967 return true; 1968 return false; 1969 } 1970 1971 static inline 1972 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1973 { 1974 return ctx->num; 1975 } 1976 1977 /* Latencies incurred by various limits for a sender. They are 1978 * chronograph-like stats that are mutually exclusive. 1979 */ 1980 enum tcp_chrono { 1981 TCP_CHRONO_UNSPEC, 1982 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1983 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1984 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1985 __TCP_CHRONO_MAX, 1986 }; 1987 1988 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1989 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1990 1991 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1992 * the same memory storage than skb->destructor/_skb_refdst 1993 */ 1994 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1995 { 1996 skb->destructor = NULL; 1997 skb->_skb_refdst = 0UL; 1998 } 1999 2000 #define tcp_skb_tsorted_save(skb) { \ 2001 unsigned long _save = skb->_skb_refdst; \ 2002 skb->_skb_refdst = 0UL; 2003 2004 #define tcp_skb_tsorted_restore(skb) \ 2005 skb->_skb_refdst = _save; \ 2006 } 2007 2008 void tcp_write_queue_purge(struct sock *sk); 2009 2010 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 2011 { 2012 return skb_rb_first(&sk->tcp_rtx_queue); 2013 } 2014 2015 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 2016 { 2017 return skb_rb_last(&sk->tcp_rtx_queue); 2018 } 2019 2020 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 2021 { 2022 return skb_peek_tail(&sk->sk_write_queue); 2023 } 2024 2025 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 2026 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 2027 2028 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 2029 { 2030 return skb_peek(&sk->sk_write_queue); 2031 } 2032 2033 static inline bool tcp_skb_is_last(const struct sock *sk, 2034 const struct sk_buff *skb) 2035 { 2036 return skb_queue_is_last(&sk->sk_write_queue, skb); 2037 } 2038 2039 /** 2040 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 2041 * @sk: socket 2042 * 2043 * Since the write queue can have a temporary empty skb in it, 2044 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 2045 */ 2046 static inline bool tcp_write_queue_empty(const struct sock *sk) 2047 { 2048 const struct tcp_sock *tp = tcp_sk(sk); 2049 2050 return tp->write_seq == tp->snd_nxt; 2051 } 2052 2053 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 2054 { 2055 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 2056 } 2057 2058 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 2059 { 2060 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 2061 } 2062 2063 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 2064 { 2065 __skb_queue_tail(&sk->sk_write_queue, skb); 2066 2067 /* Queue it, remembering where we must start sending. */ 2068 if (sk->sk_write_queue.next == skb) 2069 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 2070 } 2071 2072 /* Insert new before skb on the write queue of sk. */ 2073 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 2074 struct sk_buff *skb, 2075 struct sock *sk) 2076 { 2077 __skb_queue_before(&sk->sk_write_queue, skb, new); 2078 } 2079 2080 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 2081 { 2082 tcp_skb_tsorted_anchor_cleanup(skb); 2083 __skb_unlink(skb, &sk->sk_write_queue); 2084 } 2085 2086 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 2087 2088 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 2089 { 2090 tcp_skb_tsorted_anchor_cleanup(skb); 2091 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 2092 } 2093 2094 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 2095 { 2096 list_del(&skb->tcp_tsorted_anchor); 2097 tcp_rtx_queue_unlink(skb, sk); 2098 tcp_wmem_free_skb(sk, skb); 2099 } 2100 2101 static inline void tcp_push_pending_frames(struct sock *sk) 2102 { 2103 if (tcp_send_head(sk)) { 2104 struct tcp_sock *tp = tcp_sk(sk); 2105 2106 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 2107 } 2108 } 2109 2110 /* Start sequence of the skb just after the highest skb with SACKed 2111 * bit, valid only if sacked_out > 0 or when the caller has ensured 2112 * validity by itself. 2113 */ 2114 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 2115 { 2116 if (!tp->sacked_out) 2117 return tp->snd_una; 2118 2119 if (tp->highest_sack == NULL) 2120 return tp->snd_nxt; 2121 2122 return TCP_SKB_CB(tp->highest_sack)->seq; 2123 } 2124 2125 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 2126 { 2127 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 2128 } 2129 2130 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 2131 { 2132 return tcp_sk(sk)->highest_sack; 2133 } 2134 2135 static inline void tcp_highest_sack_reset(struct sock *sk) 2136 { 2137 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 2138 } 2139 2140 /* Called when old skb is about to be deleted and replaced by new skb */ 2141 static inline void tcp_highest_sack_replace(struct sock *sk, 2142 struct sk_buff *old, 2143 struct sk_buff *new) 2144 { 2145 if (old == tcp_highest_sack(sk)) 2146 tcp_sk(sk)->highest_sack = new; 2147 } 2148 2149 /* This helper checks if socket has IP_TRANSPARENT set */ 2150 static inline bool inet_sk_transparent(const struct sock *sk) 2151 { 2152 switch (sk->sk_state) { 2153 case TCP_TIME_WAIT: 2154 return inet_twsk(sk)->tw_transparent; 2155 case TCP_NEW_SYN_RECV: 2156 return inet_rsk(inet_reqsk(sk))->no_srccheck; 2157 } 2158 return inet_test_bit(TRANSPARENT, sk); 2159 } 2160 2161 /* Determines whether this is a thin stream (which may suffer from 2162 * increased latency). Used to trigger latency-reducing mechanisms. 2163 */ 2164 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 2165 { 2166 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 2167 } 2168 2169 /* /proc */ 2170 enum tcp_seq_states { 2171 TCP_SEQ_STATE_LISTENING, 2172 TCP_SEQ_STATE_ESTABLISHED, 2173 }; 2174 2175 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 2176 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 2177 void tcp_seq_stop(struct seq_file *seq, void *v); 2178 2179 struct tcp_seq_afinfo { 2180 sa_family_t family; 2181 }; 2182 2183 struct tcp_iter_state { 2184 struct seq_net_private p; 2185 enum tcp_seq_states state; 2186 struct sock *syn_wait_sk; 2187 int bucket, offset, sbucket, num; 2188 loff_t last_pos; 2189 }; 2190 2191 extern struct request_sock_ops tcp_request_sock_ops; 2192 extern struct request_sock_ops tcp6_request_sock_ops; 2193 2194 void tcp_v4_destroy_sock(struct sock *sk); 2195 2196 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 2197 netdev_features_t features); 2198 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 2199 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 2200 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 2201 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 2202 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 2203 #ifdef CONFIG_INET 2204 void tcp_gro_complete(struct sk_buff *skb); 2205 #else 2206 static inline void tcp_gro_complete(struct sk_buff *skb) { } 2207 #endif 2208 2209 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 2210 2211 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 2212 { 2213 struct net *net = sock_net((struct sock *)tp); 2214 u32 val; 2215 2216 val = READ_ONCE(tp->notsent_lowat); 2217 2218 return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); 2219 } 2220 2221 bool tcp_stream_memory_free(const struct sock *sk, int wake); 2222 2223 #ifdef CONFIG_PROC_FS 2224 int tcp4_proc_init(void); 2225 void tcp4_proc_exit(void); 2226 #endif 2227 2228 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2229 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2230 const struct tcp_request_sock_ops *af_ops, 2231 struct sock *sk, struct sk_buff *skb); 2232 2233 /* TCP af-specific functions */ 2234 struct tcp_sock_af_ops { 2235 #ifdef CONFIG_TCP_MD5SIG 2236 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2237 const struct sock *addr_sk); 2238 int (*calc_md5_hash)(char *location, 2239 const struct tcp_md5sig_key *md5, 2240 const struct sock *sk, 2241 const struct sk_buff *skb); 2242 int (*md5_parse)(struct sock *sk, 2243 int optname, 2244 sockptr_t optval, 2245 int optlen); 2246 #endif 2247 #ifdef CONFIG_TCP_AO 2248 int (*ao_parse)(struct sock *sk, int optname, sockptr_t optval, int optlen); 2249 struct tcp_ao_key *(*ao_lookup)(const struct sock *sk, 2250 struct sock *addr_sk, 2251 int sndid, int rcvid); 2252 int (*ao_calc_key_sk)(struct tcp_ao_key *mkt, u8 *key, 2253 const struct sock *sk, 2254 __be32 sisn, __be32 disn, bool send); 2255 int (*calc_ao_hash)(char *location, struct tcp_ao_key *ao, 2256 const struct sock *sk, const struct sk_buff *skb, 2257 const u8 *tkey, int hash_offset, u32 sne); 2258 #endif 2259 }; 2260 2261 struct tcp_request_sock_ops { 2262 u16 mss_clamp; 2263 #ifdef CONFIG_TCP_MD5SIG 2264 struct tcp_md5sig_key *(*req_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 #endif 2271 #ifdef CONFIG_TCP_AO 2272 struct tcp_ao_key *(*ao_lookup)(const struct sock *sk, 2273 struct request_sock *req, 2274 int sndid, int rcvid); 2275 int (*ao_calc_key)(struct tcp_ao_key *mkt, u8 *key, struct request_sock *sk); 2276 int (*ao_synack_hash)(char *ao_hash, struct tcp_ao_key *mkt, 2277 struct request_sock *req, const struct sk_buff *skb, 2278 int hash_offset, u32 sne); 2279 #endif 2280 #ifdef CONFIG_SYN_COOKIES 2281 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2282 __u16 *mss); 2283 #endif 2284 struct dst_entry *(*route_req)(const struct sock *sk, 2285 struct sk_buff *skb, 2286 struct flowi *fl, 2287 struct request_sock *req, 2288 u32 tw_isn); 2289 u32 (*init_seq)(const struct sk_buff *skb); 2290 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2291 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2292 struct flowi *fl, struct request_sock *req, 2293 struct tcp_fastopen_cookie *foc, 2294 enum tcp_synack_type synack_type, 2295 struct sk_buff *syn_skb); 2296 }; 2297 2298 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2299 #if IS_ENABLED(CONFIG_IPV6) 2300 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2301 #endif 2302 2303 #ifdef CONFIG_SYN_COOKIES 2304 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2305 const struct sock *sk, struct sk_buff *skb, 2306 __u16 *mss) 2307 { 2308 tcp_synq_overflow(sk); 2309 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2310 return ops->cookie_init_seq(skb, mss); 2311 } 2312 #else 2313 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2314 const struct sock *sk, struct sk_buff *skb, 2315 __u16 *mss) 2316 { 2317 return 0; 2318 } 2319 #endif 2320 2321 struct tcp_key { 2322 union { 2323 struct { 2324 struct tcp_ao_key *ao_key; 2325 char *traffic_key; 2326 u32 sne; 2327 u8 rcv_next; 2328 }; 2329 struct tcp_md5sig_key *md5_key; 2330 }; 2331 enum { 2332 TCP_KEY_NONE = 0, 2333 TCP_KEY_MD5, 2334 TCP_KEY_AO, 2335 } type; 2336 }; 2337 2338 static inline void tcp_get_current_key(const struct sock *sk, 2339 struct tcp_key *out) 2340 { 2341 #if defined(CONFIG_TCP_AO) || defined(CONFIG_TCP_MD5SIG) 2342 const struct tcp_sock *tp = tcp_sk(sk); 2343 #endif 2344 2345 #ifdef CONFIG_TCP_AO 2346 if (static_branch_unlikely(&tcp_ao_needed.key)) { 2347 struct tcp_ao_info *ao; 2348 2349 ao = rcu_dereference_protected(tp->ao_info, 2350 lockdep_sock_is_held(sk)); 2351 if (ao) { 2352 out->ao_key = READ_ONCE(ao->current_key); 2353 out->type = TCP_KEY_AO; 2354 return; 2355 } 2356 } 2357 #endif 2358 #ifdef CONFIG_TCP_MD5SIG 2359 if (static_branch_unlikely(&tcp_md5_needed.key) && 2360 rcu_access_pointer(tp->md5sig_info)) { 2361 out->md5_key = tp->af_specific->md5_lookup(sk, sk); 2362 if (out->md5_key) { 2363 out->type = TCP_KEY_MD5; 2364 return; 2365 } 2366 } 2367 #endif 2368 out->type = TCP_KEY_NONE; 2369 } 2370 2371 static inline bool tcp_key_is_md5(const struct tcp_key *key) 2372 { 2373 #ifdef CONFIG_TCP_MD5SIG 2374 if (static_branch_unlikely(&tcp_md5_needed.key) && 2375 key->type == TCP_KEY_MD5) 2376 return true; 2377 #endif 2378 return false; 2379 } 2380 2381 static inline bool tcp_key_is_ao(const struct tcp_key *key) 2382 { 2383 #ifdef CONFIG_TCP_AO 2384 if (static_branch_unlikely(&tcp_ao_needed.key) && 2385 key->type == TCP_KEY_AO) 2386 return true; 2387 #endif 2388 return false; 2389 } 2390 2391 int tcpv4_offload_init(void); 2392 2393 void tcp_v4_init(void); 2394 void tcp_init(void); 2395 2396 /* tcp_recovery.c */ 2397 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2398 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2399 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2400 u32 reo_wnd); 2401 extern bool tcp_rack_mark_lost(struct sock *sk); 2402 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2403 u64 xmit_time); 2404 extern void tcp_rack_reo_timeout(struct sock *sk); 2405 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2406 2407 /* tcp_plb.c */ 2408 2409 /* 2410 * Scaling factor for fractions in PLB. For example, tcp_plb_update_state 2411 * expects cong_ratio which represents fraction of traffic that experienced 2412 * congestion over a single RTT. In order to avoid floating point operations, 2413 * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in. 2414 */ 2415 #define TCP_PLB_SCALE 8 2416 2417 /* State for PLB (Protective Load Balancing) for a single TCP connection. */ 2418 struct tcp_plb_state { 2419 u8 consec_cong_rounds:5, /* consecutive congested rounds */ 2420 unused:3; 2421 u32 pause_until; /* jiffies32 when PLB can resume rerouting */ 2422 }; 2423 2424 static inline void tcp_plb_init(const struct sock *sk, 2425 struct tcp_plb_state *plb) 2426 { 2427 plb->consec_cong_rounds = 0; 2428 plb->pause_until = 0; 2429 } 2430 void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb, 2431 const int cong_ratio); 2432 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb); 2433 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb); 2434 2435 /* At how many usecs into the future should the RTO fire? */ 2436 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2437 { 2438 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2439 u32 rto = inet_csk(sk)->icsk_rto; 2440 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2441 2442 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2443 } 2444 2445 /* 2446 * Save and compile IPv4 options, return a pointer to it 2447 */ 2448 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2449 struct sk_buff *skb) 2450 { 2451 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2452 struct ip_options_rcu *dopt = NULL; 2453 2454 if (opt->optlen) { 2455 int opt_size = sizeof(*dopt) + opt->optlen; 2456 2457 dopt = kmalloc(opt_size, GFP_ATOMIC); 2458 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2459 kfree(dopt); 2460 dopt = NULL; 2461 } 2462 } 2463 return dopt; 2464 } 2465 2466 /* locally generated TCP pure ACKs have skb->truesize == 2 2467 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2468 * This is much faster than dissecting the packet to find out. 2469 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2470 */ 2471 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2472 { 2473 return skb->truesize == 2; 2474 } 2475 2476 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2477 { 2478 skb->truesize = 2; 2479 } 2480 2481 static inline int tcp_inq(struct sock *sk) 2482 { 2483 struct tcp_sock *tp = tcp_sk(sk); 2484 int answ; 2485 2486 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2487 answ = 0; 2488 } else if (sock_flag(sk, SOCK_URGINLINE) || 2489 !tp->urg_data || 2490 before(tp->urg_seq, tp->copied_seq) || 2491 !before(tp->urg_seq, tp->rcv_nxt)) { 2492 2493 answ = tp->rcv_nxt - tp->copied_seq; 2494 2495 /* Subtract 1, if FIN was received */ 2496 if (answ && sock_flag(sk, SOCK_DONE)) 2497 answ--; 2498 } else { 2499 answ = tp->urg_seq - tp->copied_seq; 2500 } 2501 2502 return answ; 2503 } 2504 2505 int tcp_peek_len(struct socket *sock); 2506 2507 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2508 { 2509 u16 segs_in; 2510 2511 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2512 2513 /* We update these fields while other threads might 2514 * read them from tcp_get_info() 2515 */ 2516 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2517 if (skb->len > tcp_hdrlen(skb)) 2518 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2519 } 2520 2521 /* 2522 * TCP listen path runs lockless. 2523 * We forced "struct sock" to be const qualified to make sure 2524 * we don't modify one of its field by mistake. 2525 * Here, we increment sk_drops which is an atomic_t, so we can safely 2526 * make sock writable again. 2527 */ 2528 static inline void tcp_listendrop(const struct sock *sk) 2529 { 2530 atomic_inc(&((struct sock *)sk)->sk_drops); 2531 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2532 } 2533 2534 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2535 2536 /* 2537 * Interface for adding Upper Level Protocols over TCP 2538 */ 2539 2540 #define TCP_ULP_NAME_MAX 16 2541 #define TCP_ULP_MAX 128 2542 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2543 2544 struct tcp_ulp_ops { 2545 struct list_head list; 2546 2547 /* initialize ulp */ 2548 int (*init)(struct sock *sk); 2549 /* update ulp */ 2550 void (*update)(struct sock *sk, struct proto *p, 2551 void (*write_space)(struct sock *sk)); 2552 /* cleanup ulp */ 2553 void (*release)(struct sock *sk); 2554 /* diagnostic */ 2555 int (*get_info)(struct sock *sk, struct sk_buff *skb); 2556 size_t (*get_info_size)(const struct sock *sk); 2557 /* clone ulp */ 2558 void (*clone)(const struct request_sock *req, struct sock *newsk, 2559 const gfp_t priority); 2560 2561 char name[TCP_ULP_NAME_MAX]; 2562 struct module *owner; 2563 }; 2564 int tcp_register_ulp(struct tcp_ulp_ops *type); 2565 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2566 int tcp_set_ulp(struct sock *sk, const char *name); 2567 void tcp_get_available_ulp(char *buf, size_t len); 2568 void tcp_cleanup_ulp(struct sock *sk); 2569 void tcp_update_ulp(struct sock *sk, struct proto *p, 2570 void (*write_space)(struct sock *sk)); 2571 2572 #define MODULE_ALIAS_TCP_ULP(name) \ 2573 __MODULE_INFO(alias, alias_userspace, name); \ 2574 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2575 2576 #ifdef CONFIG_NET_SOCK_MSG 2577 struct sk_msg; 2578 struct sk_psock; 2579 2580 #ifdef CONFIG_BPF_SYSCALL 2581 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2582 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2583 #endif /* CONFIG_BPF_SYSCALL */ 2584 2585 #ifdef CONFIG_INET 2586 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); 2587 #else 2588 static inline void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) 2589 { 2590 } 2591 #endif 2592 2593 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 2594 struct sk_msg *msg, u32 bytes, int flags); 2595 #endif /* CONFIG_NET_SOCK_MSG */ 2596 2597 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2598 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2599 { 2600 } 2601 #endif 2602 2603 #ifdef CONFIG_CGROUP_BPF 2604 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2605 struct sk_buff *skb, 2606 unsigned int end_offset) 2607 { 2608 skops->skb = skb; 2609 skops->skb_data_end = skb->data + end_offset; 2610 } 2611 #else 2612 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2613 struct sk_buff *skb, 2614 unsigned int end_offset) 2615 { 2616 } 2617 #endif 2618 2619 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2620 * is < 0, then the BPF op failed (for example if the loaded BPF 2621 * program does not support the chosen operation or there is no BPF 2622 * program loaded). 2623 */ 2624 #ifdef CONFIG_BPF 2625 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2626 { 2627 struct bpf_sock_ops_kern sock_ops; 2628 int ret; 2629 2630 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2631 if (sk_fullsock(sk)) { 2632 sock_ops.is_fullsock = 1; 2633 sock_owned_by_me(sk); 2634 } 2635 2636 sock_ops.sk = sk; 2637 sock_ops.op = op; 2638 if (nargs > 0) 2639 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2640 2641 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2642 if (ret == 0) 2643 ret = sock_ops.reply; 2644 else 2645 ret = -1; 2646 return ret; 2647 } 2648 2649 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2650 { 2651 u32 args[2] = {arg1, arg2}; 2652 2653 return tcp_call_bpf(sk, op, 2, args); 2654 } 2655 2656 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2657 u32 arg3) 2658 { 2659 u32 args[3] = {arg1, arg2, arg3}; 2660 2661 return tcp_call_bpf(sk, op, 3, args); 2662 } 2663 2664 #else 2665 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2666 { 2667 return -EPERM; 2668 } 2669 2670 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2671 { 2672 return -EPERM; 2673 } 2674 2675 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2676 u32 arg3) 2677 { 2678 return -EPERM; 2679 } 2680 2681 #endif 2682 2683 static inline u32 tcp_timeout_init(struct sock *sk) 2684 { 2685 int timeout; 2686 2687 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2688 2689 if (timeout <= 0) 2690 timeout = TCP_TIMEOUT_INIT; 2691 return min_t(int, timeout, TCP_RTO_MAX); 2692 } 2693 2694 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2695 { 2696 int rwnd; 2697 2698 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2699 2700 if (rwnd < 0) 2701 rwnd = 0; 2702 return rwnd; 2703 } 2704 2705 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2706 { 2707 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2708 } 2709 2710 static inline void tcp_bpf_rtt(struct sock *sk) 2711 { 2712 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2713 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2714 } 2715 2716 #if IS_ENABLED(CONFIG_SMC) 2717 extern struct static_key_false tcp_have_smc; 2718 #endif 2719 2720 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2721 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2722 void (*cad)(struct sock *sk, u32 ack_seq)); 2723 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2724 void clean_acked_data_flush(void); 2725 #endif 2726 2727 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2728 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2729 const struct tcp_sock *tp) 2730 { 2731 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2732 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2733 } 2734 2735 /* Compute Earliest Departure Time for some control packets 2736 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2737 */ 2738 static inline u64 tcp_transmit_time(const struct sock *sk) 2739 { 2740 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2741 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2742 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2743 2744 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2745 } 2746 return 0; 2747 } 2748 2749 static inline int tcp_parse_auth_options(const struct tcphdr *th, 2750 const u8 **md5_hash, const struct tcp_ao_hdr **aoh) 2751 { 2752 const u8 *md5_tmp, *ao_tmp; 2753 int ret; 2754 2755 ret = tcp_do_parse_auth_options(th, &md5_tmp, &ao_tmp); 2756 if (ret) 2757 return ret; 2758 2759 if (md5_hash) 2760 *md5_hash = md5_tmp; 2761 2762 if (aoh) { 2763 if (!ao_tmp) 2764 *aoh = NULL; 2765 else 2766 *aoh = (struct tcp_ao_hdr *)(ao_tmp - 2); 2767 } 2768 2769 return 0; 2770 } 2771 2772 static inline bool tcp_ao_required(struct sock *sk, const void *saddr, 2773 int family, int l3index, bool stat_inc) 2774 { 2775 #ifdef CONFIG_TCP_AO 2776 struct tcp_ao_info *ao_info; 2777 struct tcp_ao_key *ao_key; 2778 2779 if (!static_branch_unlikely(&tcp_ao_needed.key)) 2780 return false; 2781 2782 ao_info = rcu_dereference_check(tcp_sk(sk)->ao_info, 2783 lockdep_sock_is_held(sk)); 2784 if (!ao_info) 2785 return false; 2786 2787 ao_key = tcp_ao_do_lookup(sk, l3index, saddr, family, -1, -1); 2788 if (ao_info->ao_required || ao_key) { 2789 if (stat_inc) { 2790 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOREQUIRED); 2791 atomic64_inc(&ao_info->counters.ao_required); 2792 } 2793 return true; 2794 } 2795 #endif 2796 return false; 2797 } 2798 2799 /* Called with rcu_read_lock() */ 2800 static inline enum skb_drop_reason 2801 tcp_inbound_hash(struct sock *sk, const struct request_sock *req, 2802 const struct sk_buff *skb, 2803 const void *saddr, const void *daddr, 2804 int family, int dif, int sdif) 2805 { 2806 const struct tcphdr *th = tcp_hdr(skb); 2807 const struct tcp_ao_hdr *aoh; 2808 const __u8 *md5_location; 2809 int l3index; 2810 2811 /* Invalid option or two times meet any of auth options */ 2812 if (tcp_parse_auth_options(th, &md5_location, &aoh)) { 2813 tcp_hash_fail("TCP segment has incorrect auth options set", 2814 family, skb, ""); 2815 return SKB_DROP_REASON_TCP_AUTH_HDR; 2816 } 2817 2818 if (req) { 2819 if (tcp_rsk_used_ao(req) != !!aoh) { 2820 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD); 2821 tcp_hash_fail("TCP connection can't start/end using TCP-AO", 2822 family, skb, "%s", 2823 !aoh ? "missing AO" : "AO signed"); 2824 return SKB_DROP_REASON_TCP_AOFAILURE; 2825 } 2826 } 2827 2828 /* sdif set, means packet ingressed via a device 2829 * in an L3 domain and dif is set to the l3mdev 2830 */ 2831 l3index = sdif ? dif : 0; 2832 2833 /* Fast path: unsigned segments */ 2834 if (likely(!md5_location && !aoh)) { 2835 /* Drop if there's TCP-MD5 or TCP-AO key with any rcvid/sndid 2836 * for the remote peer. On TCP-AO established connection 2837 * the last key is impossible to remove, so there's 2838 * always at least one current_key. 2839 */ 2840 if (tcp_ao_required(sk, saddr, family, l3index, true)) { 2841 tcp_hash_fail("AO hash is required, but not found", 2842 family, skb, "L3 index %d", l3index); 2843 return SKB_DROP_REASON_TCP_AONOTFOUND; 2844 } 2845 if (unlikely(tcp_md5_do_lookup(sk, l3index, saddr, family))) { 2846 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); 2847 tcp_hash_fail("MD5 Hash not found", 2848 family, skb, "L3 index %d", l3index); 2849 return SKB_DROP_REASON_TCP_MD5NOTFOUND; 2850 } 2851 return SKB_NOT_DROPPED_YET; 2852 } 2853 2854 if (aoh) 2855 return tcp_inbound_ao_hash(sk, skb, family, req, l3index, aoh); 2856 2857 return tcp_inbound_md5_hash(sk, skb, saddr, daddr, family, 2858 l3index, md5_location); 2859 } 2860 2861 #endif /* _TCP_H */ 2862