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 void tcp_time_wait(struct sock *sk, int state, int timeo); 56 57 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) 58 #define MAX_TCP_OPTION_SPACE 40 59 #define TCP_MIN_SND_MSS 48 60 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 61 62 /* 63 * Never offer a window over 32767 without using window scaling. Some 64 * poor stacks do signed 16bit maths! 65 */ 66 #define MAX_TCP_WINDOW 32767U 67 68 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 69 #define TCP_MIN_MSS 88U 70 71 /* The initial MTU to use for probing */ 72 #define TCP_BASE_MSS 1024 73 74 /* probing interval, default to 10 minutes as per RFC4821 */ 75 #define TCP_PROBE_INTERVAL 600 76 77 /* Specify interval when tcp mtu probing will stop */ 78 #define TCP_PROBE_THRESHOLD 8 79 80 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 81 #define TCP_FASTRETRANS_THRESH 3 82 83 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 84 #define TCP_MAX_QUICKACKS 16U 85 86 /* Maximal number of window scale according to RFC1323 */ 87 #define TCP_MAX_WSCALE 14U 88 89 /* urg_data states */ 90 #define TCP_URG_VALID 0x0100 91 #define TCP_URG_NOTYET 0x0200 92 #define TCP_URG_READ 0x0400 93 94 #define TCP_RETR1 3 /* 95 * This is how many retries it does before it 96 * tries to figure out if the gateway is 97 * down. Minimal RFC value is 3; it corresponds 98 * to ~3sec-8min depending on RTO. 99 */ 100 101 #define TCP_RETR2 15 /* 102 * This should take at least 103 * 90 minutes to time out. 104 * RFC1122 says that the limit is 100 sec. 105 * 15 is ~13-30min depending on RTO. 106 */ 107 108 #define TCP_SYN_RETRIES 6 /* This is how many retries are done 109 * when active opening a connection. 110 * RFC1122 says the minimum retry MUST 111 * be at least 180secs. Nevertheless 112 * this value is corresponding to 113 * 63secs of retransmission with the 114 * current initial RTO. 115 */ 116 117 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done 118 * when passive opening a connection. 119 * This is corresponding to 31secs of 120 * retransmission with the current 121 * initial RTO. 122 */ 123 124 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 125 * state, about 60 seconds */ 126 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 127 /* BSD style FIN_WAIT2 deadlock breaker. 128 * It used to be 3min, new value is 60sec, 129 * to combine FIN-WAIT-2 timeout with 130 * TIME-WAIT timer. 131 */ 132 #define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */ 133 134 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 135 static_assert((1 << ATO_BITS) > TCP_DELACK_MAX); 136 137 #if HZ >= 100 138 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 139 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 140 #else 141 #define TCP_DELACK_MIN 4U 142 #define TCP_ATO_MIN 4U 143 #endif 144 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 145 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 146 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ 147 148 #define TCP_TIMEOUT_MIN_US (2*USEC_PER_MSEC) /* Min TCP timeout in microsecs */ 149 150 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 151 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 152 * used as a fallback RTO for the 153 * initial data transmission if no 154 * valid RTT sample has been acquired, 155 * most likely due to retrans in 3WHS. 156 */ 157 158 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 159 * for local resources. 160 */ 161 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 162 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 163 #define TCP_KEEPALIVE_INTVL (75*HZ) 164 165 #define MAX_TCP_KEEPIDLE 32767 166 #define MAX_TCP_KEEPINTVL 32767 167 #define MAX_TCP_KEEPCNT 127 168 #define MAX_TCP_SYNCNT 127 169 170 /* Ensure that TCP PAWS checks are relaxed after ~2147 seconds 171 * to avoid overflows. This assumes a clock smaller than 1 Mhz. 172 * Default clock is 1 Khz, tcp_usec_ts uses 1 Mhz. 173 */ 174 #define TCP_PAWS_WRAP (INT_MAX / USEC_PER_SEC) 175 176 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 177 * after this time. It should be equal 178 * (or greater than) TCP_TIMEWAIT_LEN 179 * to provide reliability equal to one 180 * provided by timewait state. 181 */ 182 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 183 * timestamps. It must be less than 184 * minimal timewait lifetime. 185 */ 186 /* 187 * TCP option 188 */ 189 190 #define TCPOPT_NOP 1 /* Padding */ 191 #define TCPOPT_EOL 0 /* End of options */ 192 #define TCPOPT_MSS 2 /* Segment size negotiating */ 193 #define TCPOPT_WINDOW 3 /* Window scaling */ 194 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 195 #define TCPOPT_SACK 5 /* SACK Block */ 196 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 197 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 198 #define TCPOPT_AO 29 /* Authentication Option (RFC5925) */ 199 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ 200 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 201 #define TCPOPT_EXP 254 /* Experimental */ 202 /* Magic number to be after the option value for sharing TCP 203 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 204 */ 205 #define TCPOPT_FASTOPEN_MAGIC 0xF989 206 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 207 208 /* 209 * TCP option lengths 210 */ 211 212 #define TCPOLEN_MSS 4 213 #define TCPOLEN_WINDOW 3 214 #define TCPOLEN_SACK_PERM 2 215 #define TCPOLEN_TIMESTAMP 10 216 #define TCPOLEN_MD5SIG 18 217 #define TCPOLEN_FASTOPEN_BASE 2 218 #define TCPOLEN_EXP_FASTOPEN_BASE 4 219 #define TCPOLEN_EXP_SMC_BASE 6 220 221 /* But this is what stacks really send out. */ 222 #define TCPOLEN_TSTAMP_ALIGNED 12 223 #define TCPOLEN_WSCALE_ALIGNED 4 224 #define TCPOLEN_SACKPERM_ALIGNED 4 225 #define TCPOLEN_SACK_BASE 2 226 #define TCPOLEN_SACK_BASE_ALIGNED 4 227 #define TCPOLEN_SACK_PERBLOCK 8 228 #define TCPOLEN_MD5SIG_ALIGNED 20 229 #define TCPOLEN_MSS_ALIGNED 4 230 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 231 232 /* Flags in tp->nonagle */ 233 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 234 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 235 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 236 237 /* TCP thin-stream limits */ 238 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 239 240 /* TCP initial congestion window as per rfc6928 */ 241 #define TCP_INIT_CWND 10 242 243 /* Bit Flags for sysctl_tcp_fastopen */ 244 #define TFO_CLIENT_ENABLE 1 245 #define TFO_SERVER_ENABLE 2 246 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 247 248 /* Accept SYN data w/o any cookie option */ 249 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 250 251 /* Force enable TFO on all listeners, i.e., not requiring the 252 * TCP_FASTOPEN socket option. 253 */ 254 #define TFO_SERVER_WO_SOCKOPT1 0x400 255 256 257 /* sysctl variables for tcp */ 258 extern int sysctl_tcp_max_orphans; 259 extern long sysctl_tcp_mem[3]; 260 261 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 262 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 263 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 264 265 extern atomic_long_t tcp_memory_allocated; 266 DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); 267 268 extern struct percpu_counter tcp_sockets_allocated; 269 extern unsigned long tcp_memory_pressure; 270 271 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 272 static inline bool tcp_under_memory_pressure(const struct sock *sk) 273 { 274 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 275 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 276 return true; 277 278 return READ_ONCE(tcp_memory_pressure); 279 } 280 /* 281 * The next routines deal with comparing 32 bit unsigned ints 282 * and worry about wraparound (automatic with unsigned arithmetic). 283 */ 284 285 static inline bool before(__u32 seq1, __u32 seq2) 286 { 287 return (__s32)(seq1-seq2) < 0; 288 } 289 #define after(seq2, seq1) before(seq1, seq2) 290 291 /* is s2<=s1<=s3 ? */ 292 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 293 { 294 return seq3 - seq2 >= seq1 - seq2; 295 } 296 297 static inline bool tcp_out_of_memory(struct sock *sk) 298 { 299 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 300 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 301 return true; 302 return false; 303 } 304 305 static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb) 306 { 307 sk_wmem_queued_add(sk, -skb->truesize); 308 if (!skb_zcopy_pure(skb)) 309 sk_mem_uncharge(sk, skb->truesize); 310 else 311 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb))); 312 __kfree_skb(skb); 313 } 314 315 void sk_forced_mem_schedule(struct sock *sk, int size); 316 317 bool tcp_check_oom(struct sock *sk, int shift); 318 319 320 extern struct proto tcp_prot; 321 322 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 323 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 324 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 325 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 326 327 void tcp_tasklet_init(void); 328 329 int tcp_v4_err(struct sk_buff *skb, u32); 330 331 void tcp_shutdown(struct sock *sk, int how); 332 333 int tcp_v4_early_demux(struct sk_buff *skb); 334 int tcp_v4_rcv(struct sk_buff *skb); 335 336 void tcp_remove_empty_skb(struct sock *sk); 337 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 338 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 339 int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, 340 size_t size, struct ubuf_info *uarg); 341 void tcp_splice_eof(struct socket *sock); 342 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 343 int tcp_wmem_schedule(struct sock *sk, int copy); 344 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 345 int size_goal); 346 void tcp_release_cb(struct sock *sk); 347 void tcp_wfree(struct sk_buff *skb); 348 void tcp_write_timer_handler(struct sock *sk); 349 void tcp_delack_timer_handler(struct sock *sk); 350 int tcp_ioctl(struct sock *sk, int cmd, int *karg); 351 enum skb_drop_reason tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 352 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 353 void tcp_rcv_space_adjust(struct sock *sk); 354 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 355 void tcp_twsk_destructor(struct sock *sk); 356 void tcp_twsk_purge(struct list_head *net_exit_list, int family); 357 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 358 struct pipe_inode_info *pipe, size_t len, 359 unsigned int flags); 360 struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp, 361 bool force_schedule); 362 363 static inline void tcp_dec_quickack_mode(struct sock *sk) 364 { 365 struct inet_connection_sock *icsk = inet_csk(sk); 366 367 if (icsk->icsk_ack.quick) { 368 /* How many ACKs S/ACKing new data have we sent? */ 369 const unsigned int pkts = inet_csk_ack_scheduled(sk) ? 1 : 0; 370 371 if (pkts >= icsk->icsk_ack.quick) { 372 icsk->icsk_ack.quick = 0; 373 /* Leaving quickack mode we deflate ATO. */ 374 icsk->icsk_ack.ato = TCP_ATO_MIN; 375 } else 376 icsk->icsk_ack.quick -= pkts; 377 } 378 } 379 380 #define TCP_ECN_OK 1 381 #define TCP_ECN_QUEUE_CWR 2 382 #define TCP_ECN_DEMAND_CWR 4 383 #define TCP_ECN_SEEN 8 384 385 enum tcp_tw_status { 386 TCP_TW_SUCCESS = 0, 387 TCP_TW_RST = 1, 388 TCP_TW_ACK = 2, 389 TCP_TW_SYN = 3 390 }; 391 392 393 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 394 struct sk_buff *skb, 395 const struct tcphdr *th); 396 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 397 struct request_sock *req, bool fastopen, 398 bool *lost_race); 399 enum skb_drop_reason tcp_child_process(struct sock *parent, struct sock *child, 400 struct sk_buff *skb); 401 void tcp_enter_loss(struct sock *sk); 402 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag); 403 void tcp_clear_retrans(struct tcp_sock *tp); 404 void tcp_update_metrics(struct sock *sk); 405 void tcp_init_metrics(struct sock *sk); 406 void tcp_metrics_init(void); 407 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 408 void __tcp_close(struct sock *sk, long timeout); 409 void tcp_close(struct sock *sk, long timeout); 410 void tcp_init_sock(struct sock *sk); 411 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb); 412 __poll_t tcp_poll(struct file *file, struct socket *sock, 413 struct poll_table_struct *wait); 414 int do_tcp_getsockopt(struct sock *sk, int level, 415 int optname, sockptr_t optval, sockptr_t optlen); 416 int tcp_getsockopt(struct sock *sk, int level, int optname, 417 char __user *optval, int __user *optlen); 418 bool tcp_bpf_bypass_getsockopt(int level, int optname); 419 int do_tcp_setsockopt(struct sock *sk, int level, int optname, 420 sockptr_t optval, unsigned int optlen); 421 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 422 unsigned int optlen); 423 void tcp_set_keepalive(struct sock *sk, int val); 424 void tcp_syn_ack_timeout(const struct request_sock *req); 425 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 426 int flags, int *addr_len); 427 int tcp_set_rcvlowat(struct sock *sk, int val); 428 int tcp_set_window_clamp(struct sock *sk, int val); 429 void tcp_update_recv_tstamps(struct sk_buff *skb, 430 struct scm_timestamping_internal *tss); 431 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, 432 struct scm_timestamping_internal *tss); 433 void tcp_data_ready(struct sock *sk); 434 #ifdef CONFIG_MMU 435 int tcp_mmap(struct file *file, struct socket *sock, 436 struct vm_area_struct *vma); 437 #endif 438 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 439 struct tcp_options_received *opt_rx, 440 int estab, struct tcp_fastopen_cookie *foc); 441 442 /* 443 * BPF SKB-less helpers 444 */ 445 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 446 struct tcphdr *th, u32 *cookie); 447 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 448 struct tcphdr *th, u32 *cookie); 449 u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss); 450 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 451 const struct tcp_request_sock_ops *af_ops, 452 struct sock *sk, struct tcphdr *th); 453 /* 454 * TCP v4 functions exported for the inet6 API 455 */ 456 457 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 458 void tcp_v4_mtu_reduced(struct sock *sk); 459 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 460 void tcp_ld_RTO_revert(struct sock *sk, u32 seq); 461 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 462 struct sock *tcp_create_openreq_child(const struct sock *sk, 463 struct request_sock *req, 464 struct sk_buff *skb); 465 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 466 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 467 struct request_sock *req, 468 struct dst_entry *dst, 469 struct request_sock *req_unhash, 470 bool *own_req); 471 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 472 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 473 int tcp_connect(struct sock *sk); 474 enum tcp_synack_type { 475 TCP_SYNACK_NORMAL, 476 TCP_SYNACK_FASTOPEN, 477 TCP_SYNACK_COOKIE, 478 }; 479 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 480 struct request_sock *req, 481 struct tcp_fastopen_cookie *foc, 482 enum tcp_synack_type synack_type, 483 struct sk_buff *syn_skb); 484 int tcp_disconnect(struct sock *sk, int flags); 485 486 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 487 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 488 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 489 490 /* From syncookies.c */ 491 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 492 struct request_sock *req, 493 struct dst_entry *dst); 494 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th); 495 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 496 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops, 497 struct sock *sk, struct sk_buff *skb, 498 struct tcp_options_received *tcp_opt, 499 int mss, u32 tsoff); 500 501 #if IS_ENABLED(CONFIG_BPF) 502 struct bpf_tcp_req_attrs { 503 u32 rcv_tsval; 504 u32 rcv_tsecr; 505 u16 mss; 506 u8 rcv_wscale; 507 u8 snd_wscale; 508 u8 ecn_ok; 509 u8 wscale_ok; 510 u8 sack_ok; 511 u8 tstamp_ok; 512 u8 usec_ts_ok; 513 u8 reserved[3]; 514 }; 515 #endif 516 517 #ifdef CONFIG_SYN_COOKIES 518 519 /* Syncookies use a monotonic timer which increments every 60 seconds. 520 * This counter is used both as a hash input and partially encoded into 521 * the cookie value. A cookie is only validated further if the delta 522 * between the current counter value and the encoded one is less than this, 523 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 524 * the counter advances immediately after a cookie is generated). 525 */ 526 #define MAX_SYNCOOKIE_AGE 2 527 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 528 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 529 530 /* syncookies: remember time of last synqueue overflow 531 * But do not dirty this field too often (once per second is enough) 532 * It is racy as we do not hold a lock, but race is very minor. 533 */ 534 static inline void tcp_synq_overflow(const struct sock *sk) 535 { 536 unsigned int last_overflow; 537 unsigned int now = jiffies; 538 539 if (sk->sk_reuseport) { 540 struct sock_reuseport *reuse; 541 542 reuse = rcu_dereference(sk->sk_reuseport_cb); 543 if (likely(reuse)) { 544 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 545 if (!time_between32(now, last_overflow, 546 last_overflow + HZ)) 547 WRITE_ONCE(reuse->synq_overflow_ts, now); 548 return; 549 } 550 } 551 552 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 553 if (!time_between32(now, last_overflow, last_overflow + HZ)) 554 WRITE_ONCE(tcp_sk_rw(sk)->rx_opt.ts_recent_stamp, now); 555 } 556 557 /* syncookies: no recent synqueue overflow on this listening socket? */ 558 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 559 { 560 unsigned int last_overflow; 561 unsigned int now = jiffies; 562 563 if (sk->sk_reuseport) { 564 struct sock_reuseport *reuse; 565 566 reuse = rcu_dereference(sk->sk_reuseport_cb); 567 if (likely(reuse)) { 568 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 569 return !time_between32(now, last_overflow - HZ, 570 last_overflow + 571 TCP_SYNCOOKIE_VALID); 572 } 573 } 574 575 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 576 577 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 578 * then we're under synflood. However, we have to use 579 * 'last_overflow - HZ' as lower bound. That's because a concurrent 580 * tcp_synq_overflow() could update .ts_recent_stamp after we read 581 * jiffies but before we store .ts_recent_stamp into last_overflow, 582 * which could lead to rejecting a valid syncookie. 583 */ 584 return !time_between32(now, last_overflow - HZ, 585 last_overflow + TCP_SYNCOOKIE_VALID); 586 } 587 588 static inline u32 tcp_cookie_time(void) 589 { 590 u64 val = get_jiffies_64(); 591 592 do_div(val, TCP_SYNCOOKIE_PERIOD); 593 return val; 594 } 595 596 /* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */ 597 static inline u64 tcp_ns_to_ts(bool usec_ts, u64 val) 598 { 599 if (usec_ts) 600 return div_u64(val, NSEC_PER_USEC); 601 602 return div_u64(val, NSEC_PER_MSEC); 603 } 604 605 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 606 u16 *mssp); 607 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 608 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 609 bool cookie_timestamp_decode(const struct net *net, 610 struct tcp_options_received *opt); 611 612 static inline bool cookie_ecn_ok(const struct net *net, const struct dst_entry *dst) 613 { 614 return READ_ONCE(net->ipv4.sysctl_tcp_ecn) || 615 dst_feature(dst, RTAX_FEATURE_ECN); 616 } 617 618 #if IS_ENABLED(CONFIG_BPF) 619 static inline bool cookie_bpf_ok(struct sk_buff *skb) 620 { 621 return skb->sk; 622 } 623 624 struct request_sock *cookie_bpf_check(struct sock *sk, struct sk_buff *skb); 625 #else 626 static inline bool cookie_bpf_ok(struct sk_buff *skb) 627 { 628 return false; 629 } 630 631 static inline struct request_sock *cookie_bpf_check(struct net *net, struct sock *sk, 632 struct sk_buff *skb) 633 { 634 return NULL; 635 } 636 #endif 637 638 /* From net/ipv6/syncookies.c */ 639 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th); 640 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 641 642 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 643 const struct tcphdr *th, u16 *mssp); 644 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 645 #endif 646 /* tcp_output.c */ 647 648 void tcp_skb_entail(struct sock *sk, struct sk_buff *skb); 649 void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb); 650 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 651 int nonagle); 652 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 653 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 654 void tcp_retransmit_timer(struct sock *sk); 655 void tcp_xmit_retransmit_queue(struct sock *); 656 void tcp_simple_retransmit(struct sock *); 657 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 658 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 659 enum tcp_queue { 660 TCP_FRAG_IN_WRITE_QUEUE, 661 TCP_FRAG_IN_RTX_QUEUE, 662 }; 663 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 664 struct sk_buff *skb, u32 len, 665 unsigned int mss_now, gfp_t gfp); 666 667 void tcp_send_probe0(struct sock *); 668 int tcp_write_wakeup(struct sock *, int mib); 669 void tcp_send_fin(struct sock *sk); 670 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 671 int tcp_send_synack(struct sock *); 672 void tcp_push_one(struct sock *, unsigned int mss_now); 673 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 674 void tcp_send_ack(struct sock *sk); 675 void tcp_send_delayed_ack(struct sock *sk); 676 void tcp_send_loss_probe(struct sock *sk); 677 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 678 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 679 const struct sk_buff *next_skb); 680 681 /* tcp_input.c */ 682 void tcp_rearm_rto(struct sock *sk); 683 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 684 void tcp_reset(struct sock *sk, struct sk_buff *skb); 685 void tcp_fin(struct sock *sk); 686 void tcp_check_space(struct sock *sk); 687 void tcp_sack_compress_send_ack(struct sock *sk); 688 689 /* tcp_timer.c */ 690 void tcp_init_xmit_timers(struct sock *); 691 static inline void tcp_clear_xmit_timers(struct sock *sk) 692 { 693 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 694 __sock_put(sk); 695 696 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 697 __sock_put(sk); 698 699 inet_csk_clear_xmit_timers(sk); 700 } 701 702 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 703 unsigned int tcp_current_mss(struct sock *sk); 704 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 705 706 /* Bound MSS / TSO packet size with the half of the window */ 707 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 708 { 709 int cutoff; 710 711 /* When peer uses tiny windows, there is no use in packetizing 712 * to sub-MSS pieces for the sake of SWS or making sure there 713 * are enough packets in the pipe for fast recovery. 714 * 715 * On the other hand, for extremely large MSS devices, handling 716 * smaller than MSS windows in this way does make sense. 717 */ 718 if (tp->max_window > TCP_MSS_DEFAULT) 719 cutoff = (tp->max_window >> 1); 720 else 721 cutoff = tp->max_window; 722 723 if (cutoff && pktsize > cutoff) 724 return max_t(int, cutoff, 68U - tp->tcp_header_len); 725 else 726 return pktsize; 727 } 728 729 /* tcp.c */ 730 void tcp_get_info(struct sock *, struct tcp_info *); 731 732 /* Read 'sendfile()'-style from a TCP socket */ 733 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 734 sk_read_actor_t recv_actor); 735 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 736 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off); 737 void tcp_read_done(struct sock *sk, size_t len); 738 739 void tcp_initialize_rcv_mss(struct sock *sk); 740 741 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 742 int tcp_mss_to_mtu(struct sock *sk, int mss); 743 void tcp_mtup_init(struct sock *sk); 744 745 static inline void tcp_bound_rto(const struct sock *sk) 746 { 747 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 748 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 749 } 750 751 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 752 { 753 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 754 } 755 756 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 757 { 758 /* mptcp hooks are only on the slow path */ 759 if (sk_is_mptcp((struct sock *)tp)) 760 return; 761 762 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 763 ntohl(TCP_FLAG_ACK) | 764 snd_wnd); 765 } 766 767 static inline void tcp_fast_path_on(struct tcp_sock *tp) 768 { 769 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 770 } 771 772 static inline void tcp_fast_path_check(struct sock *sk) 773 { 774 struct tcp_sock *tp = tcp_sk(sk); 775 776 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 777 tp->rcv_wnd && 778 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 779 !tp->urg_data) 780 tcp_fast_path_on(tp); 781 } 782 783 u32 tcp_delack_max(const struct sock *sk); 784 785 /* Compute the actual rto_min value */ 786 static inline u32 tcp_rto_min(const struct sock *sk) 787 { 788 const struct dst_entry *dst = __sk_dst_get(sk); 789 u32 rto_min = inet_csk(sk)->icsk_rto_min; 790 791 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 792 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 793 return rto_min; 794 } 795 796 static inline u32 tcp_rto_min_us(const struct sock *sk) 797 { 798 return jiffies_to_usecs(tcp_rto_min(sk)); 799 } 800 801 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 802 { 803 return dst_metric_locked(dst, RTAX_CC_ALGO); 804 } 805 806 /* Minimum RTT in usec. ~0 means not available. */ 807 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 808 { 809 return minmax_get(&tp->rtt_min); 810 } 811 812 /* Compute the actual receive window we are currently advertising. 813 * Rcv_nxt can be after the window if our peer push more data 814 * than the offered window. 815 */ 816 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 817 { 818 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 819 820 if (win < 0) 821 win = 0; 822 return (u32) win; 823 } 824 825 /* Choose a new window, without checks for shrinking, and without 826 * scaling applied to the result. The caller does these things 827 * if necessary. This is a "raw" window selection. 828 */ 829 u32 __tcp_select_window(struct sock *sk); 830 831 void tcp_send_window_probe(struct sock *sk); 832 833 /* TCP uses 32bit jiffies to save some space. 834 * Note that this is different from tcp_time_stamp, which 835 * historically has been the same until linux-4.13. 836 */ 837 #define tcp_jiffies32 ((u32)jiffies) 838 839 /* 840 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 841 * It is no longer tied to jiffies, but to 1 ms clock. 842 * Note: double check if you want to use tcp_jiffies32 instead of this. 843 */ 844 #define TCP_TS_HZ 1000 845 846 static inline u64 tcp_clock_ns(void) 847 { 848 return ktime_get_ns(); 849 } 850 851 static inline u64 tcp_clock_us(void) 852 { 853 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 854 } 855 856 static inline u64 tcp_clock_ms(void) 857 { 858 return div_u64(tcp_clock_ns(), NSEC_PER_MSEC); 859 } 860 861 /* TCP Timestamp included in TS option (RFC 1323) can either use ms 862 * or usec resolution. Each socket carries a flag to select one or other 863 * resolution, as the route attribute could change anytime. 864 * Each flow must stick to initial resolution. 865 */ 866 static inline u32 tcp_clock_ts(bool usec_ts) 867 { 868 return usec_ts ? tcp_clock_us() : tcp_clock_ms(); 869 } 870 871 static inline u32 tcp_time_stamp_ms(const struct tcp_sock *tp) 872 { 873 return div_u64(tp->tcp_mstamp, USEC_PER_MSEC); 874 } 875 876 static inline u32 tcp_time_stamp_ts(const struct tcp_sock *tp) 877 { 878 if (tp->tcp_usec_ts) 879 return tp->tcp_mstamp; 880 return tcp_time_stamp_ms(tp); 881 } 882 883 void tcp_mstamp_refresh(struct tcp_sock *tp); 884 885 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 886 { 887 return max_t(s64, t1 - t0, 0); 888 } 889 890 /* provide the departure time in us unit */ 891 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 892 { 893 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 894 } 895 896 /* Provide skb TSval in usec or ms unit */ 897 static inline u32 tcp_skb_timestamp_ts(bool usec_ts, const struct sk_buff *skb) 898 { 899 if (usec_ts) 900 return tcp_skb_timestamp_us(skb); 901 902 return div_u64(skb->skb_mstamp_ns, NSEC_PER_MSEC); 903 } 904 905 static inline u32 tcp_tw_tsval(const struct tcp_timewait_sock *tcptw) 906 { 907 return tcp_clock_ts(tcptw->tw_sk.tw_usec_ts) + tcptw->tw_ts_offset; 908 } 909 910 static inline u32 tcp_rsk_tsval(const struct tcp_request_sock *treq) 911 { 912 return tcp_clock_ts(treq->req_usec_ts) + treq->ts_off; 913 } 914 915 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 916 917 #define TCPHDR_FIN 0x01 918 #define TCPHDR_SYN 0x02 919 #define TCPHDR_RST 0x04 920 #define TCPHDR_PSH 0x08 921 #define TCPHDR_ACK 0x10 922 #define TCPHDR_URG 0x20 923 #define TCPHDR_ECE 0x40 924 #define TCPHDR_CWR 0x80 925 926 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 927 928 /* This is what the send packet queuing engine uses to pass 929 * TCP per-packet control information to the transmission code. 930 * We also store the host-order sequence numbers in here too. 931 * This is 44 bytes if IPV6 is enabled. 932 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 933 */ 934 struct tcp_skb_cb { 935 __u32 seq; /* Starting sequence number */ 936 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 937 union { 938 /* Note : tcp_tw_isn is used in input path only 939 * (isn chosen by tcp_timewait_state_process()) 940 * 941 * tcp_gso_segs/size are used in write queue only, 942 * cf tcp_skb_pcount()/tcp_skb_mss() 943 */ 944 __u32 tcp_tw_isn; 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 (*init_seq)(const struct sk_buff *skb); 2289 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2290 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2291 struct flowi *fl, struct request_sock *req, 2292 struct tcp_fastopen_cookie *foc, 2293 enum tcp_synack_type synack_type, 2294 struct sk_buff *syn_skb); 2295 }; 2296 2297 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2298 #if IS_ENABLED(CONFIG_IPV6) 2299 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2300 #endif 2301 2302 #ifdef CONFIG_SYN_COOKIES 2303 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2304 const struct sock *sk, struct sk_buff *skb, 2305 __u16 *mss) 2306 { 2307 tcp_synq_overflow(sk); 2308 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2309 return ops->cookie_init_seq(skb, mss); 2310 } 2311 #else 2312 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2313 const struct sock *sk, struct sk_buff *skb, 2314 __u16 *mss) 2315 { 2316 return 0; 2317 } 2318 #endif 2319 2320 struct tcp_key { 2321 union { 2322 struct { 2323 struct tcp_ao_key *ao_key; 2324 char *traffic_key; 2325 u32 sne; 2326 u8 rcv_next; 2327 }; 2328 struct tcp_md5sig_key *md5_key; 2329 }; 2330 enum { 2331 TCP_KEY_NONE = 0, 2332 TCP_KEY_MD5, 2333 TCP_KEY_AO, 2334 } type; 2335 }; 2336 2337 static inline void tcp_get_current_key(const struct sock *sk, 2338 struct tcp_key *out) 2339 { 2340 #if defined(CONFIG_TCP_AO) || defined(CONFIG_TCP_MD5SIG) 2341 const struct tcp_sock *tp = tcp_sk(sk); 2342 #endif 2343 2344 #ifdef CONFIG_TCP_AO 2345 if (static_branch_unlikely(&tcp_ao_needed.key)) { 2346 struct tcp_ao_info *ao; 2347 2348 ao = rcu_dereference_protected(tp->ao_info, 2349 lockdep_sock_is_held(sk)); 2350 if (ao) { 2351 out->ao_key = READ_ONCE(ao->current_key); 2352 out->type = TCP_KEY_AO; 2353 return; 2354 } 2355 } 2356 #endif 2357 #ifdef CONFIG_TCP_MD5SIG 2358 if (static_branch_unlikely(&tcp_md5_needed.key) && 2359 rcu_access_pointer(tp->md5sig_info)) { 2360 out->md5_key = tp->af_specific->md5_lookup(sk, sk); 2361 if (out->md5_key) { 2362 out->type = TCP_KEY_MD5; 2363 return; 2364 } 2365 } 2366 #endif 2367 out->type = TCP_KEY_NONE; 2368 } 2369 2370 static inline bool tcp_key_is_md5(const struct tcp_key *key) 2371 { 2372 #ifdef CONFIG_TCP_MD5SIG 2373 if (static_branch_unlikely(&tcp_md5_needed.key) && 2374 key->type == TCP_KEY_MD5) 2375 return true; 2376 #endif 2377 return false; 2378 } 2379 2380 static inline bool tcp_key_is_ao(const struct tcp_key *key) 2381 { 2382 #ifdef CONFIG_TCP_AO 2383 if (static_branch_unlikely(&tcp_ao_needed.key) && 2384 key->type == TCP_KEY_AO) 2385 return true; 2386 #endif 2387 return false; 2388 } 2389 2390 int tcpv4_offload_init(void); 2391 2392 void tcp_v4_init(void); 2393 void tcp_init(void); 2394 2395 /* tcp_recovery.c */ 2396 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2397 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2398 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2399 u32 reo_wnd); 2400 extern bool tcp_rack_mark_lost(struct sock *sk); 2401 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2402 u64 xmit_time); 2403 extern void tcp_rack_reo_timeout(struct sock *sk); 2404 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2405 2406 /* tcp_plb.c */ 2407 2408 /* 2409 * Scaling factor for fractions in PLB. For example, tcp_plb_update_state 2410 * expects cong_ratio which represents fraction of traffic that experienced 2411 * congestion over a single RTT. In order to avoid floating point operations, 2412 * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in. 2413 */ 2414 #define TCP_PLB_SCALE 8 2415 2416 /* State for PLB (Protective Load Balancing) for a single TCP connection. */ 2417 struct tcp_plb_state { 2418 u8 consec_cong_rounds:5, /* consecutive congested rounds */ 2419 unused:3; 2420 u32 pause_until; /* jiffies32 when PLB can resume rerouting */ 2421 }; 2422 2423 static inline void tcp_plb_init(const struct sock *sk, 2424 struct tcp_plb_state *plb) 2425 { 2426 plb->consec_cong_rounds = 0; 2427 plb->pause_until = 0; 2428 } 2429 void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb, 2430 const int cong_ratio); 2431 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb); 2432 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb); 2433 2434 /* At how many usecs into the future should the RTO fire? */ 2435 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2436 { 2437 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2438 u32 rto = inet_csk(sk)->icsk_rto; 2439 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2440 2441 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2442 } 2443 2444 /* 2445 * Save and compile IPv4 options, return a pointer to it 2446 */ 2447 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2448 struct sk_buff *skb) 2449 { 2450 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2451 struct ip_options_rcu *dopt = NULL; 2452 2453 if (opt->optlen) { 2454 int opt_size = sizeof(*dopt) + opt->optlen; 2455 2456 dopt = kmalloc(opt_size, GFP_ATOMIC); 2457 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2458 kfree(dopt); 2459 dopt = NULL; 2460 } 2461 } 2462 return dopt; 2463 } 2464 2465 /* locally generated TCP pure ACKs have skb->truesize == 2 2466 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2467 * This is much faster than dissecting the packet to find out. 2468 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2469 */ 2470 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2471 { 2472 return skb->truesize == 2; 2473 } 2474 2475 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2476 { 2477 skb->truesize = 2; 2478 } 2479 2480 static inline int tcp_inq(struct sock *sk) 2481 { 2482 struct tcp_sock *tp = tcp_sk(sk); 2483 int answ; 2484 2485 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2486 answ = 0; 2487 } else if (sock_flag(sk, SOCK_URGINLINE) || 2488 !tp->urg_data || 2489 before(tp->urg_seq, tp->copied_seq) || 2490 !before(tp->urg_seq, tp->rcv_nxt)) { 2491 2492 answ = tp->rcv_nxt - tp->copied_seq; 2493 2494 /* Subtract 1, if FIN was received */ 2495 if (answ && sock_flag(sk, SOCK_DONE)) 2496 answ--; 2497 } else { 2498 answ = tp->urg_seq - tp->copied_seq; 2499 } 2500 2501 return answ; 2502 } 2503 2504 int tcp_peek_len(struct socket *sock); 2505 2506 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2507 { 2508 u16 segs_in; 2509 2510 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2511 2512 /* We update these fields while other threads might 2513 * read them from tcp_get_info() 2514 */ 2515 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2516 if (skb->len > tcp_hdrlen(skb)) 2517 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2518 } 2519 2520 /* 2521 * TCP listen path runs lockless. 2522 * We forced "struct sock" to be const qualified to make sure 2523 * we don't modify one of its field by mistake. 2524 * Here, we increment sk_drops which is an atomic_t, so we can safely 2525 * make sock writable again. 2526 */ 2527 static inline void tcp_listendrop(const struct sock *sk) 2528 { 2529 atomic_inc(&((struct sock *)sk)->sk_drops); 2530 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2531 } 2532 2533 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2534 2535 /* 2536 * Interface for adding Upper Level Protocols over TCP 2537 */ 2538 2539 #define TCP_ULP_NAME_MAX 16 2540 #define TCP_ULP_MAX 128 2541 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2542 2543 struct tcp_ulp_ops { 2544 struct list_head list; 2545 2546 /* initialize ulp */ 2547 int (*init)(struct sock *sk); 2548 /* update ulp */ 2549 void (*update)(struct sock *sk, struct proto *p, 2550 void (*write_space)(struct sock *sk)); 2551 /* cleanup ulp */ 2552 void (*release)(struct sock *sk); 2553 /* diagnostic */ 2554 int (*get_info)(struct sock *sk, struct sk_buff *skb); 2555 size_t (*get_info_size)(const struct sock *sk); 2556 /* clone ulp */ 2557 void (*clone)(const struct request_sock *req, struct sock *newsk, 2558 const gfp_t priority); 2559 2560 char name[TCP_ULP_NAME_MAX]; 2561 struct module *owner; 2562 }; 2563 int tcp_register_ulp(struct tcp_ulp_ops *type); 2564 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2565 int tcp_set_ulp(struct sock *sk, const char *name); 2566 void tcp_get_available_ulp(char *buf, size_t len); 2567 void tcp_cleanup_ulp(struct sock *sk); 2568 void tcp_update_ulp(struct sock *sk, struct proto *p, 2569 void (*write_space)(struct sock *sk)); 2570 2571 #define MODULE_ALIAS_TCP_ULP(name) \ 2572 __MODULE_INFO(alias, alias_userspace, name); \ 2573 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2574 2575 #ifdef CONFIG_NET_SOCK_MSG 2576 struct sk_msg; 2577 struct sk_psock; 2578 2579 #ifdef CONFIG_BPF_SYSCALL 2580 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2581 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2582 #endif /* CONFIG_BPF_SYSCALL */ 2583 2584 #ifdef CONFIG_INET 2585 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); 2586 #else 2587 static inline void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) 2588 { 2589 } 2590 #endif 2591 2592 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 2593 struct sk_msg *msg, u32 bytes, int flags); 2594 #endif /* CONFIG_NET_SOCK_MSG */ 2595 2596 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2597 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2598 { 2599 } 2600 #endif 2601 2602 #ifdef CONFIG_CGROUP_BPF 2603 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2604 struct sk_buff *skb, 2605 unsigned int end_offset) 2606 { 2607 skops->skb = skb; 2608 skops->skb_data_end = skb->data + end_offset; 2609 } 2610 #else 2611 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2612 struct sk_buff *skb, 2613 unsigned int end_offset) 2614 { 2615 } 2616 #endif 2617 2618 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2619 * is < 0, then the BPF op failed (for example if the loaded BPF 2620 * program does not support the chosen operation or there is no BPF 2621 * program loaded). 2622 */ 2623 #ifdef CONFIG_BPF 2624 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2625 { 2626 struct bpf_sock_ops_kern sock_ops; 2627 int ret; 2628 2629 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2630 if (sk_fullsock(sk)) { 2631 sock_ops.is_fullsock = 1; 2632 sock_owned_by_me(sk); 2633 } 2634 2635 sock_ops.sk = sk; 2636 sock_ops.op = op; 2637 if (nargs > 0) 2638 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2639 2640 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2641 if (ret == 0) 2642 ret = sock_ops.reply; 2643 else 2644 ret = -1; 2645 return ret; 2646 } 2647 2648 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2649 { 2650 u32 args[2] = {arg1, arg2}; 2651 2652 return tcp_call_bpf(sk, op, 2, args); 2653 } 2654 2655 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2656 u32 arg3) 2657 { 2658 u32 args[3] = {arg1, arg2, arg3}; 2659 2660 return tcp_call_bpf(sk, op, 3, args); 2661 } 2662 2663 #else 2664 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2665 { 2666 return -EPERM; 2667 } 2668 2669 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2670 { 2671 return -EPERM; 2672 } 2673 2674 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2675 u32 arg3) 2676 { 2677 return -EPERM; 2678 } 2679 2680 #endif 2681 2682 static inline u32 tcp_timeout_init(struct sock *sk) 2683 { 2684 int timeout; 2685 2686 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2687 2688 if (timeout <= 0) 2689 timeout = TCP_TIMEOUT_INIT; 2690 return min_t(int, timeout, TCP_RTO_MAX); 2691 } 2692 2693 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2694 { 2695 int rwnd; 2696 2697 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2698 2699 if (rwnd < 0) 2700 rwnd = 0; 2701 return rwnd; 2702 } 2703 2704 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2705 { 2706 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2707 } 2708 2709 static inline void tcp_bpf_rtt(struct sock *sk) 2710 { 2711 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2712 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2713 } 2714 2715 #if IS_ENABLED(CONFIG_SMC) 2716 extern struct static_key_false tcp_have_smc; 2717 #endif 2718 2719 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2720 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2721 void (*cad)(struct sock *sk, u32 ack_seq)); 2722 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2723 void clean_acked_data_flush(void); 2724 #endif 2725 2726 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2727 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2728 const struct tcp_sock *tp) 2729 { 2730 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2731 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2732 } 2733 2734 /* Compute Earliest Departure Time for some control packets 2735 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2736 */ 2737 static inline u64 tcp_transmit_time(const struct sock *sk) 2738 { 2739 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2740 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2741 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2742 2743 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2744 } 2745 return 0; 2746 } 2747 2748 static inline int tcp_parse_auth_options(const struct tcphdr *th, 2749 const u8 **md5_hash, const struct tcp_ao_hdr **aoh) 2750 { 2751 const u8 *md5_tmp, *ao_tmp; 2752 int ret; 2753 2754 ret = tcp_do_parse_auth_options(th, &md5_tmp, &ao_tmp); 2755 if (ret) 2756 return ret; 2757 2758 if (md5_hash) 2759 *md5_hash = md5_tmp; 2760 2761 if (aoh) { 2762 if (!ao_tmp) 2763 *aoh = NULL; 2764 else 2765 *aoh = (struct tcp_ao_hdr *)(ao_tmp - 2); 2766 } 2767 2768 return 0; 2769 } 2770 2771 static inline bool tcp_ao_required(struct sock *sk, const void *saddr, 2772 int family, int l3index, bool stat_inc) 2773 { 2774 #ifdef CONFIG_TCP_AO 2775 struct tcp_ao_info *ao_info; 2776 struct tcp_ao_key *ao_key; 2777 2778 if (!static_branch_unlikely(&tcp_ao_needed.key)) 2779 return false; 2780 2781 ao_info = rcu_dereference_check(tcp_sk(sk)->ao_info, 2782 lockdep_sock_is_held(sk)); 2783 if (!ao_info) 2784 return false; 2785 2786 ao_key = tcp_ao_do_lookup(sk, l3index, saddr, family, -1, -1); 2787 if (ao_info->ao_required || ao_key) { 2788 if (stat_inc) { 2789 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOREQUIRED); 2790 atomic64_inc(&ao_info->counters.ao_required); 2791 } 2792 return true; 2793 } 2794 #endif 2795 return false; 2796 } 2797 2798 /* Called with rcu_read_lock() */ 2799 static inline enum skb_drop_reason 2800 tcp_inbound_hash(struct sock *sk, const struct request_sock *req, 2801 const struct sk_buff *skb, 2802 const void *saddr, const void *daddr, 2803 int family, int dif, int sdif) 2804 { 2805 const struct tcphdr *th = tcp_hdr(skb); 2806 const struct tcp_ao_hdr *aoh; 2807 const __u8 *md5_location; 2808 int l3index; 2809 2810 /* Invalid option or two times meet any of auth options */ 2811 if (tcp_parse_auth_options(th, &md5_location, &aoh)) { 2812 tcp_hash_fail("TCP segment has incorrect auth options set", 2813 family, skb, ""); 2814 return SKB_DROP_REASON_TCP_AUTH_HDR; 2815 } 2816 2817 if (req) { 2818 if (tcp_rsk_used_ao(req) != !!aoh) { 2819 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD); 2820 tcp_hash_fail("TCP connection can't start/end using TCP-AO", 2821 family, skb, "%s", 2822 !aoh ? "missing AO" : "AO signed"); 2823 return SKB_DROP_REASON_TCP_AOFAILURE; 2824 } 2825 } 2826 2827 /* sdif set, means packet ingressed via a device 2828 * in an L3 domain and dif is set to the l3mdev 2829 */ 2830 l3index = sdif ? dif : 0; 2831 2832 /* Fast path: unsigned segments */ 2833 if (likely(!md5_location && !aoh)) { 2834 /* Drop if there's TCP-MD5 or TCP-AO key with any rcvid/sndid 2835 * for the remote peer. On TCP-AO established connection 2836 * the last key is impossible to remove, so there's 2837 * always at least one current_key. 2838 */ 2839 if (tcp_ao_required(sk, saddr, family, l3index, true)) { 2840 tcp_hash_fail("AO hash is required, but not found", 2841 family, skb, "L3 index %d", l3index); 2842 return SKB_DROP_REASON_TCP_AONOTFOUND; 2843 } 2844 if (unlikely(tcp_md5_do_lookup(sk, l3index, saddr, family))) { 2845 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); 2846 tcp_hash_fail("MD5 Hash not found", 2847 family, skb, "L3 index %d", l3index); 2848 return SKB_DROP_REASON_TCP_MD5NOTFOUND; 2849 } 2850 return SKB_NOT_DROPPED_YET; 2851 } 2852 2853 if (aoh) 2854 return tcp_inbound_ao_hash(sk, skb, family, req, l3index, aoh); 2855 2856 return tcp_inbound_md5_hash(sk, skb, saddr, daddr, family, 2857 l3index, md5_location); 2858 } 2859 2860 #endif /* _TCP_H */ 2861