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/inet_ecn.h> 41 #include <net/dst.h> 42 #include <net/mptcp.h> 43 44 #include <linux/seq_file.h> 45 #include <linux/memcontrol.h> 46 #include <linux/bpf-cgroup.h> 47 #include <linux/siphash.h> 48 49 extern struct inet_hashinfo tcp_hashinfo; 50 51 extern struct percpu_counter tcp_orphan_count; 52 void tcp_time_wait(struct sock *sk, int state, int timeo); 53 54 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) 55 #define MAX_TCP_OPTION_SPACE 40 56 #define TCP_MIN_SND_MSS 48 57 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 58 59 /* 60 * Never offer a window over 32767 without using window scaling. Some 61 * poor stacks do signed 16bit maths! 62 */ 63 #define MAX_TCP_WINDOW 32767U 64 65 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 66 #define TCP_MIN_MSS 88U 67 68 /* The initial MTU to use for probing */ 69 #define TCP_BASE_MSS 1024 70 71 /* probing interval, default to 10 minutes as per RFC4821 */ 72 #define TCP_PROBE_INTERVAL 600 73 74 /* Specify interval when tcp mtu probing will stop */ 75 #define TCP_PROBE_THRESHOLD 8 76 77 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 78 #define TCP_FASTRETRANS_THRESH 3 79 80 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 81 #define TCP_MAX_QUICKACKS 16U 82 83 /* Maximal number of window scale according to RFC1323 */ 84 #define TCP_MAX_WSCALE 14U 85 86 /* urg_data states */ 87 #define TCP_URG_VALID 0x0100 88 #define TCP_URG_NOTYET 0x0200 89 #define TCP_URG_READ 0x0400 90 91 #define TCP_RETR1 3 /* 92 * This is how many retries it does before it 93 * tries to figure out if the gateway is 94 * down. Minimal RFC value is 3; it corresponds 95 * to ~3sec-8min depending on RTO. 96 */ 97 98 #define TCP_RETR2 15 /* 99 * This should take at least 100 * 90 minutes to time out. 101 * RFC1122 says that the limit is 100 sec. 102 * 15 is ~13-30min depending on RTO. 103 */ 104 105 #define TCP_SYN_RETRIES 6 /* This is how many retries are done 106 * when active opening a connection. 107 * RFC1122 says the minimum retry MUST 108 * be at least 180secs. Nevertheless 109 * this value is corresponding to 110 * 63secs of retransmission with the 111 * current initial RTO. 112 */ 113 114 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done 115 * when passive opening a connection. 116 * This is corresponding to 31secs of 117 * retransmission with the current 118 * initial RTO. 119 */ 120 121 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 122 * state, about 60 seconds */ 123 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 124 /* BSD style FIN_WAIT2 deadlock breaker. 125 * It used to be 3min, new value is 60sec, 126 * to combine FIN-WAIT-2 timeout with 127 * TIME-WAIT timer. 128 */ 129 #define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */ 130 131 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 132 #if HZ >= 100 133 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 134 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 135 #else 136 #define TCP_DELACK_MIN 4U 137 #define TCP_ATO_MIN 4U 138 #endif 139 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 140 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 141 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ 142 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 143 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 144 * used as a fallback RTO for the 145 * initial data transmission if no 146 * valid RTT sample has been acquired, 147 * most likely due to retrans in 3WHS. 148 */ 149 150 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 151 * for local resources. 152 */ 153 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 154 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 155 #define TCP_KEEPALIVE_INTVL (75*HZ) 156 157 #define MAX_TCP_KEEPIDLE 32767 158 #define MAX_TCP_KEEPINTVL 32767 159 #define MAX_TCP_KEEPCNT 127 160 #define MAX_TCP_SYNCNT 127 161 162 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 163 164 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 165 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 166 * after this time. It should be equal 167 * (or greater than) TCP_TIMEWAIT_LEN 168 * to provide reliability equal to one 169 * provided by timewait state. 170 */ 171 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 172 * timestamps. It must be less than 173 * minimal timewait lifetime. 174 */ 175 /* 176 * TCP option 177 */ 178 179 #define TCPOPT_NOP 1 /* Padding */ 180 #define TCPOPT_EOL 0 /* End of options */ 181 #define TCPOPT_MSS 2 /* Segment size negotiating */ 182 #define TCPOPT_WINDOW 3 /* Window scaling */ 183 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 184 #define TCPOPT_SACK 5 /* SACK Block */ 185 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 186 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 187 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ 188 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 189 #define TCPOPT_EXP 254 /* Experimental */ 190 /* Magic number to be after the option value for sharing TCP 191 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 192 */ 193 #define TCPOPT_FASTOPEN_MAGIC 0xF989 194 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 195 196 /* 197 * TCP option lengths 198 */ 199 200 #define TCPOLEN_MSS 4 201 #define TCPOLEN_WINDOW 3 202 #define TCPOLEN_SACK_PERM 2 203 #define TCPOLEN_TIMESTAMP 10 204 #define TCPOLEN_MD5SIG 18 205 #define TCPOLEN_FASTOPEN_BASE 2 206 #define TCPOLEN_EXP_FASTOPEN_BASE 4 207 #define TCPOLEN_EXP_SMC_BASE 6 208 209 /* But this is what stacks really send out. */ 210 #define TCPOLEN_TSTAMP_ALIGNED 12 211 #define TCPOLEN_WSCALE_ALIGNED 4 212 #define TCPOLEN_SACKPERM_ALIGNED 4 213 #define TCPOLEN_SACK_BASE 2 214 #define TCPOLEN_SACK_BASE_ALIGNED 4 215 #define TCPOLEN_SACK_PERBLOCK 8 216 #define TCPOLEN_MD5SIG_ALIGNED 20 217 #define TCPOLEN_MSS_ALIGNED 4 218 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 219 220 /* Flags in tp->nonagle */ 221 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 222 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 223 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 224 225 /* TCP thin-stream limits */ 226 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 227 228 /* TCP initial congestion window as per rfc6928 */ 229 #define TCP_INIT_CWND 10 230 231 /* Bit Flags for sysctl_tcp_fastopen */ 232 #define TFO_CLIENT_ENABLE 1 233 #define TFO_SERVER_ENABLE 2 234 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 235 236 /* Accept SYN data w/o any cookie option */ 237 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 238 239 /* Force enable TFO on all listeners, i.e., not requiring the 240 * TCP_FASTOPEN socket option. 241 */ 242 #define TFO_SERVER_WO_SOCKOPT1 0x400 243 244 245 /* sysctl variables for tcp */ 246 extern int sysctl_tcp_max_orphans; 247 extern long sysctl_tcp_mem[3]; 248 249 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 250 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 251 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 252 253 extern atomic_long_t tcp_memory_allocated; 254 extern struct percpu_counter tcp_sockets_allocated; 255 extern unsigned long tcp_memory_pressure; 256 257 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 258 static inline bool tcp_under_memory_pressure(const struct sock *sk) 259 { 260 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 261 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 262 return true; 263 264 return READ_ONCE(tcp_memory_pressure); 265 } 266 /* 267 * The next routines deal with comparing 32 bit unsigned ints 268 * and worry about wraparound (automatic with unsigned arithmetic). 269 */ 270 271 static inline bool before(__u32 seq1, __u32 seq2) 272 { 273 return (__s32)(seq1-seq2) < 0; 274 } 275 #define after(seq2, seq1) before(seq1, seq2) 276 277 /* is s2<=s1<=s3 ? */ 278 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 279 { 280 return seq3 - seq2 >= seq1 - seq2; 281 } 282 283 static inline bool tcp_out_of_memory(struct sock *sk) 284 { 285 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 286 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 287 return true; 288 return false; 289 } 290 291 void sk_forced_mem_schedule(struct sock *sk, int size); 292 293 static inline bool tcp_too_many_orphans(struct sock *sk, int shift) 294 { 295 struct percpu_counter *ocp = sk->sk_prot->orphan_count; 296 int orphans = percpu_counter_read_positive(ocp); 297 298 if (orphans << shift > sysctl_tcp_max_orphans) { 299 orphans = percpu_counter_sum_positive(ocp); 300 if (orphans << shift > sysctl_tcp_max_orphans) 301 return true; 302 } 303 return false; 304 } 305 306 bool tcp_check_oom(struct sock *sk, int shift); 307 308 309 extern struct proto tcp_prot; 310 311 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 312 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 313 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 314 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 315 316 void tcp_tasklet_init(void); 317 318 int tcp_v4_err(struct sk_buff *skb, u32); 319 320 void tcp_shutdown(struct sock *sk, int how); 321 322 int tcp_v4_early_demux(struct sk_buff *skb); 323 int tcp_v4_rcv(struct sk_buff *skb); 324 325 void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb); 326 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 327 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 328 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 329 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, 330 int flags); 331 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, 332 size_t size, int flags); 333 struct sk_buff *tcp_build_frag(struct sock *sk, int size_goal, int flags, 334 struct page *page, int offset, size_t *size); 335 ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 336 size_t size, int flags); 337 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 338 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 339 int size_goal); 340 void tcp_release_cb(struct sock *sk); 341 void tcp_wfree(struct sk_buff *skb); 342 void tcp_write_timer_handler(struct sock *sk); 343 void tcp_delack_timer_handler(struct sock *sk); 344 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); 345 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 346 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 347 void tcp_rcv_space_adjust(struct sock *sk); 348 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 349 void tcp_twsk_destructor(struct sock *sk); 350 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 351 struct pipe_inode_info *pipe, size_t len, 352 unsigned int flags); 353 354 void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks); 355 static inline void tcp_dec_quickack_mode(struct sock *sk, 356 const unsigned int pkts) 357 { 358 struct inet_connection_sock *icsk = inet_csk(sk); 359 360 if (icsk->icsk_ack.quick) { 361 if (pkts >= icsk->icsk_ack.quick) { 362 icsk->icsk_ack.quick = 0; 363 /* Leaving quickack mode we deflate ATO. */ 364 icsk->icsk_ack.ato = TCP_ATO_MIN; 365 } else 366 icsk->icsk_ack.quick -= pkts; 367 } 368 } 369 370 #define TCP_ECN_OK 1 371 #define TCP_ECN_QUEUE_CWR 2 372 #define TCP_ECN_DEMAND_CWR 4 373 #define TCP_ECN_SEEN 8 374 375 enum tcp_tw_status { 376 TCP_TW_SUCCESS = 0, 377 TCP_TW_RST = 1, 378 TCP_TW_ACK = 2, 379 TCP_TW_SYN = 3 380 }; 381 382 383 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 384 struct sk_buff *skb, 385 const struct tcphdr *th); 386 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 387 struct request_sock *req, bool fastopen, 388 bool *lost_race); 389 int tcp_child_process(struct sock *parent, struct sock *child, 390 struct sk_buff *skb); 391 void tcp_enter_loss(struct sock *sk); 392 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag); 393 void tcp_clear_retrans(struct tcp_sock *tp); 394 void tcp_update_metrics(struct sock *sk); 395 void tcp_init_metrics(struct sock *sk); 396 void tcp_metrics_init(void); 397 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 398 void __tcp_close(struct sock *sk, long timeout); 399 void tcp_close(struct sock *sk, long timeout); 400 void tcp_init_sock(struct sock *sk); 401 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb); 402 __poll_t tcp_poll(struct file *file, struct socket *sock, 403 struct poll_table_struct *wait); 404 int tcp_getsockopt(struct sock *sk, int level, int optname, 405 char __user *optval, int __user *optlen); 406 bool tcp_bpf_bypass_getsockopt(int level, int optname); 407 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 408 unsigned int optlen); 409 void tcp_set_keepalive(struct sock *sk, int val); 410 void tcp_syn_ack_timeout(const struct request_sock *req); 411 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 412 int flags, int *addr_len); 413 int tcp_set_rcvlowat(struct sock *sk, int val); 414 int tcp_set_window_clamp(struct sock *sk, int val); 415 void tcp_update_recv_tstamps(struct sk_buff *skb, 416 struct scm_timestamping_internal *tss); 417 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, 418 struct scm_timestamping_internal *tss); 419 void tcp_data_ready(struct sock *sk); 420 #ifdef CONFIG_MMU 421 int tcp_mmap(struct file *file, struct socket *sock, 422 struct vm_area_struct *vma); 423 #endif 424 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 425 struct tcp_options_received *opt_rx, 426 int estab, struct tcp_fastopen_cookie *foc); 427 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); 428 429 /* 430 * BPF SKB-less helpers 431 */ 432 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 433 struct tcphdr *th, u32 *cookie); 434 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 435 struct tcphdr *th, u32 *cookie); 436 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 437 const struct tcp_request_sock_ops *af_ops, 438 struct sock *sk, struct tcphdr *th); 439 /* 440 * TCP v4 functions exported for the inet6 API 441 */ 442 443 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 444 void tcp_v4_mtu_reduced(struct sock *sk); 445 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 446 void tcp_ld_RTO_revert(struct sock *sk, u32 seq); 447 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 448 struct sock *tcp_create_openreq_child(const struct sock *sk, 449 struct request_sock *req, 450 struct sk_buff *skb); 451 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 452 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 453 struct request_sock *req, 454 struct dst_entry *dst, 455 struct request_sock *req_unhash, 456 bool *own_req); 457 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 458 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 459 int tcp_connect(struct sock *sk); 460 enum tcp_synack_type { 461 TCP_SYNACK_NORMAL, 462 TCP_SYNACK_FASTOPEN, 463 TCP_SYNACK_COOKIE, 464 }; 465 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 466 struct request_sock *req, 467 struct tcp_fastopen_cookie *foc, 468 enum tcp_synack_type synack_type, 469 struct sk_buff *syn_skb); 470 int tcp_disconnect(struct sock *sk, int flags); 471 472 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 473 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 474 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 475 476 /* From syncookies.c */ 477 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 478 struct request_sock *req, 479 struct dst_entry *dst, u32 tsoff); 480 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, 481 u32 cookie); 482 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 483 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops, 484 struct sock *sk, struct sk_buff *skb); 485 #ifdef CONFIG_SYN_COOKIES 486 487 /* Syncookies use a monotonic timer which increments every 60 seconds. 488 * This counter is used both as a hash input and partially encoded into 489 * the cookie value. A cookie is only validated further if the delta 490 * between the current counter value and the encoded one is less than this, 491 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 492 * the counter advances immediately after a cookie is generated). 493 */ 494 #define MAX_SYNCOOKIE_AGE 2 495 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 496 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 497 498 /* syncookies: remember time of last synqueue overflow 499 * But do not dirty this field too often (once per second is enough) 500 * It is racy as we do not hold a lock, but race is very minor. 501 */ 502 static inline void tcp_synq_overflow(const struct sock *sk) 503 { 504 unsigned int last_overflow; 505 unsigned int now = jiffies; 506 507 if (sk->sk_reuseport) { 508 struct sock_reuseport *reuse; 509 510 reuse = rcu_dereference(sk->sk_reuseport_cb); 511 if (likely(reuse)) { 512 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 513 if (!time_between32(now, last_overflow, 514 last_overflow + HZ)) 515 WRITE_ONCE(reuse->synq_overflow_ts, now); 516 return; 517 } 518 } 519 520 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 521 if (!time_between32(now, last_overflow, last_overflow + HZ)) 522 WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now); 523 } 524 525 /* syncookies: no recent synqueue overflow on this listening socket? */ 526 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 527 { 528 unsigned int last_overflow; 529 unsigned int now = jiffies; 530 531 if (sk->sk_reuseport) { 532 struct sock_reuseport *reuse; 533 534 reuse = rcu_dereference(sk->sk_reuseport_cb); 535 if (likely(reuse)) { 536 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 537 return !time_between32(now, last_overflow - HZ, 538 last_overflow + 539 TCP_SYNCOOKIE_VALID); 540 } 541 } 542 543 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 544 545 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 546 * then we're under synflood. However, we have to use 547 * 'last_overflow - HZ' as lower bound. That's because a concurrent 548 * tcp_synq_overflow() could update .ts_recent_stamp after we read 549 * jiffies but before we store .ts_recent_stamp into last_overflow, 550 * which could lead to rejecting a valid syncookie. 551 */ 552 return !time_between32(now, last_overflow - HZ, 553 last_overflow + TCP_SYNCOOKIE_VALID); 554 } 555 556 static inline u32 tcp_cookie_time(void) 557 { 558 u64 val = get_jiffies_64(); 559 560 do_div(val, TCP_SYNCOOKIE_PERIOD); 561 return val; 562 } 563 564 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 565 u16 *mssp); 566 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 567 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 568 bool cookie_timestamp_decode(const struct net *net, 569 struct tcp_options_received *opt); 570 bool cookie_ecn_ok(const struct tcp_options_received *opt, 571 const struct net *net, const struct dst_entry *dst); 572 573 /* From net/ipv6/syncookies.c */ 574 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, 575 u32 cookie); 576 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 577 578 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 579 const struct tcphdr *th, u16 *mssp); 580 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 581 #endif 582 /* tcp_output.c */ 583 584 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 585 int nonagle); 586 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 587 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 588 void tcp_retransmit_timer(struct sock *sk); 589 void tcp_xmit_retransmit_queue(struct sock *); 590 void tcp_simple_retransmit(struct sock *); 591 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 592 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 593 enum tcp_queue { 594 TCP_FRAG_IN_WRITE_QUEUE, 595 TCP_FRAG_IN_RTX_QUEUE, 596 }; 597 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 598 struct sk_buff *skb, u32 len, 599 unsigned int mss_now, gfp_t gfp); 600 601 void tcp_send_probe0(struct sock *); 602 void tcp_send_partial(struct sock *); 603 int tcp_write_wakeup(struct sock *, int mib); 604 void tcp_send_fin(struct sock *sk); 605 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 606 int tcp_send_synack(struct sock *); 607 void tcp_push_one(struct sock *, unsigned int mss_now); 608 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 609 void tcp_send_ack(struct sock *sk); 610 void tcp_send_delayed_ack(struct sock *sk); 611 void tcp_send_loss_probe(struct sock *sk); 612 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 613 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 614 const struct sk_buff *next_skb); 615 616 /* tcp_input.c */ 617 void tcp_rearm_rto(struct sock *sk); 618 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 619 void tcp_reset(struct sock *sk, struct sk_buff *skb); 620 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb); 621 void tcp_fin(struct sock *sk); 622 623 /* tcp_timer.c */ 624 void tcp_init_xmit_timers(struct sock *); 625 static inline void tcp_clear_xmit_timers(struct sock *sk) 626 { 627 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 628 __sock_put(sk); 629 630 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 631 __sock_put(sk); 632 633 inet_csk_clear_xmit_timers(sk); 634 } 635 636 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 637 unsigned int tcp_current_mss(struct sock *sk); 638 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 639 640 /* Bound MSS / TSO packet size with the half of the window */ 641 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 642 { 643 int cutoff; 644 645 /* When peer uses tiny windows, there is no use in packetizing 646 * to sub-MSS pieces for the sake of SWS or making sure there 647 * are enough packets in the pipe for fast recovery. 648 * 649 * On the other hand, for extremely large MSS devices, handling 650 * smaller than MSS windows in this way does make sense. 651 */ 652 if (tp->max_window > TCP_MSS_DEFAULT) 653 cutoff = (tp->max_window >> 1); 654 else 655 cutoff = tp->max_window; 656 657 if (cutoff && pktsize > cutoff) 658 return max_t(int, cutoff, 68U - tp->tcp_header_len); 659 else 660 return pktsize; 661 } 662 663 /* tcp.c */ 664 void tcp_get_info(struct sock *, struct tcp_info *); 665 666 /* Read 'sendfile()'-style from a TCP socket */ 667 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 668 sk_read_actor_t recv_actor); 669 670 void tcp_initialize_rcv_mss(struct sock *sk); 671 672 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 673 int tcp_mss_to_mtu(struct sock *sk, int mss); 674 void tcp_mtup_init(struct sock *sk); 675 676 static inline void tcp_bound_rto(const struct sock *sk) 677 { 678 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 679 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 680 } 681 682 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 683 { 684 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 685 } 686 687 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 688 { 689 /* mptcp hooks are only on the slow path */ 690 if (sk_is_mptcp((struct sock *)tp)) 691 return; 692 693 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 694 ntohl(TCP_FLAG_ACK) | 695 snd_wnd); 696 } 697 698 static inline void tcp_fast_path_on(struct tcp_sock *tp) 699 { 700 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 701 } 702 703 static inline void tcp_fast_path_check(struct sock *sk) 704 { 705 struct tcp_sock *tp = tcp_sk(sk); 706 707 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 708 tp->rcv_wnd && 709 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 710 !tp->urg_data) 711 tcp_fast_path_on(tp); 712 } 713 714 /* Compute the actual rto_min value */ 715 static inline u32 tcp_rto_min(struct sock *sk) 716 { 717 const struct dst_entry *dst = __sk_dst_get(sk); 718 u32 rto_min = inet_csk(sk)->icsk_rto_min; 719 720 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 721 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 722 return rto_min; 723 } 724 725 static inline u32 tcp_rto_min_us(struct sock *sk) 726 { 727 return jiffies_to_usecs(tcp_rto_min(sk)); 728 } 729 730 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 731 { 732 return dst_metric_locked(dst, RTAX_CC_ALGO); 733 } 734 735 /* Minimum RTT in usec. ~0 means not available. */ 736 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 737 { 738 return minmax_get(&tp->rtt_min); 739 } 740 741 /* Compute the actual receive window we are currently advertising. 742 * Rcv_nxt can be after the window if our peer push more data 743 * than the offered window. 744 */ 745 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 746 { 747 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 748 749 if (win < 0) 750 win = 0; 751 return (u32) win; 752 } 753 754 /* Choose a new window, without checks for shrinking, and without 755 * scaling applied to the result. The caller does these things 756 * if necessary. This is a "raw" window selection. 757 */ 758 u32 __tcp_select_window(struct sock *sk); 759 760 void tcp_send_window_probe(struct sock *sk); 761 762 /* TCP uses 32bit jiffies to save some space. 763 * Note that this is different from tcp_time_stamp, which 764 * historically has been the same until linux-4.13. 765 */ 766 #define tcp_jiffies32 ((u32)jiffies) 767 768 /* 769 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 770 * It is no longer tied to jiffies, but to 1 ms clock. 771 * Note: double check if you want to use tcp_jiffies32 instead of this. 772 */ 773 #define TCP_TS_HZ 1000 774 775 static inline u64 tcp_clock_ns(void) 776 { 777 return ktime_get_ns(); 778 } 779 780 static inline u64 tcp_clock_us(void) 781 { 782 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 783 } 784 785 /* This should only be used in contexts where tp->tcp_mstamp is up to date */ 786 static inline u32 tcp_time_stamp(const struct tcp_sock *tp) 787 { 788 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); 789 } 790 791 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ 792 static inline u32 tcp_ns_to_ts(u64 ns) 793 { 794 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); 795 } 796 797 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ 798 static inline u32 tcp_time_stamp_raw(void) 799 { 800 return tcp_ns_to_ts(tcp_clock_ns()); 801 } 802 803 void tcp_mstamp_refresh(struct tcp_sock *tp); 804 805 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 806 { 807 return max_t(s64, t1 - t0, 0); 808 } 809 810 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 811 { 812 return tcp_ns_to_ts(skb->skb_mstamp_ns); 813 } 814 815 /* provide the departure time in us unit */ 816 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 817 { 818 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 819 } 820 821 822 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 823 824 #define TCPHDR_FIN 0x01 825 #define TCPHDR_SYN 0x02 826 #define TCPHDR_RST 0x04 827 #define TCPHDR_PSH 0x08 828 #define TCPHDR_ACK 0x10 829 #define TCPHDR_URG 0x20 830 #define TCPHDR_ECE 0x40 831 #define TCPHDR_CWR 0x80 832 833 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 834 835 /* This is what the send packet queuing engine uses to pass 836 * TCP per-packet control information to the transmission code. 837 * We also store the host-order sequence numbers in here too. 838 * This is 44 bytes if IPV6 is enabled. 839 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 840 */ 841 struct tcp_skb_cb { 842 __u32 seq; /* Starting sequence number */ 843 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 844 union { 845 /* Note : tcp_tw_isn is used in input path only 846 * (isn chosen by tcp_timewait_state_process()) 847 * 848 * tcp_gso_segs/size are used in write queue only, 849 * cf tcp_skb_pcount()/tcp_skb_mss() 850 */ 851 __u32 tcp_tw_isn; 852 struct { 853 u16 tcp_gso_segs; 854 u16 tcp_gso_size; 855 }; 856 }; 857 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 858 859 __u8 sacked; /* State flags for SACK. */ 860 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 861 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 862 #define TCPCB_LOST 0x04 /* SKB is lost */ 863 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 864 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 865 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 866 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 867 TCPCB_REPAIRED) 868 869 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 870 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 871 eor:1, /* Is skb MSG_EOR marked? */ 872 has_rxtstamp:1, /* SKB has a RX timestamp */ 873 unused:5; 874 __u32 ack_seq; /* Sequence number ACK'd */ 875 union { 876 struct { 877 /* There is space for up to 24 bytes */ 878 __u32 in_flight:30,/* Bytes in flight at transmit */ 879 is_app_limited:1, /* cwnd not fully used? */ 880 unused:1; 881 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 882 __u32 delivered; 883 /* start of send pipeline phase */ 884 u64 first_tx_mstamp; 885 /* when we reached the "delivered" count */ 886 u64 delivered_mstamp; 887 } tx; /* only used for outgoing skbs */ 888 union { 889 struct inet_skb_parm h4; 890 #if IS_ENABLED(CONFIG_IPV6) 891 struct inet6_skb_parm h6; 892 #endif 893 } header; /* For incoming skbs */ 894 }; 895 }; 896 897 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 898 899 extern const struct inet_connection_sock_af_ops ipv4_specific; 900 901 #if IS_ENABLED(CONFIG_IPV6) 902 /* This is the variant of inet6_iif() that must be used by TCP, 903 * as TCP moves IP6CB into a different location in skb->cb[] 904 */ 905 static inline int tcp_v6_iif(const struct sk_buff *skb) 906 { 907 return TCP_SKB_CB(skb)->header.h6.iif; 908 } 909 910 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 911 { 912 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 913 914 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 915 } 916 917 /* TCP_SKB_CB reference means this can not be used from early demux */ 918 static inline int tcp_v6_sdif(const struct sk_buff *skb) 919 { 920 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 921 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 922 return TCP_SKB_CB(skb)->header.h6.iif; 923 #endif 924 return 0; 925 } 926 927 extern const struct inet_connection_sock_af_ops ipv6_specific; 928 929 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 930 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 931 INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *skb)); 932 933 #endif 934 935 /* TCP_SKB_CB reference means this can not be used from early demux */ 936 static inline int tcp_v4_sdif(struct sk_buff *skb) 937 { 938 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 939 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 940 return TCP_SKB_CB(skb)->header.h4.iif; 941 #endif 942 return 0; 943 } 944 945 /* Due to TSO, an SKB can be composed of multiple actual 946 * packets. To keep these tracked properly, we use this. 947 */ 948 static inline int tcp_skb_pcount(const struct sk_buff *skb) 949 { 950 return TCP_SKB_CB(skb)->tcp_gso_segs; 951 } 952 953 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 954 { 955 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 956 } 957 958 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 959 { 960 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 961 } 962 963 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 964 static inline int tcp_skb_mss(const struct sk_buff *skb) 965 { 966 return TCP_SKB_CB(skb)->tcp_gso_size; 967 } 968 969 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 970 { 971 return likely(!TCP_SKB_CB(skb)->eor); 972 } 973 974 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 975 const struct sk_buff *from) 976 { 977 return likely(tcp_skb_can_collapse_to(to) && 978 mptcp_skb_can_collapse(to, from)); 979 } 980 981 /* Events passed to congestion control interface */ 982 enum tcp_ca_event { 983 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 984 CA_EVENT_CWND_RESTART, /* congestion window restart */ 985 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 986 CA_EVENT_LOSS, /* loss timeout */ 987 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 988 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 989 }; 990 991 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 992 enum tcp_ca_ack_event_flags { 993 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 994 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 995 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 996 }; 997 998 /* 999 * Interface for adding new TCP congestion control handlers 1000 */ 1001 #define TCP_CA_NAME_MAX 16 1002 #define TCP_CA_MAX 128 1003 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1004 1005 #define TCP_CA_UNSPEC 0 1006 1007 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1008 #define TCP_CONG_NON_RESTRICTED 0x1 1009 /* Requires ECN/ECT set on all packets */ 1010 #define TCP_CONG_NEEDS_ECN 0x2 1011 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1012 1013 union tcp_cc_info; 1014 1015 struct ack_sample { 1016 u32 pkts_acked; 1017 s32 rtt_us; 1018 u32 in_flight; 1019 }; 1020 1021 /* A rate sample measures the number of (original/retransmitted) data 1022 * packets delivered "delivered" over an interval of time "interval_us". 1023 * The tcp_rate.c code fills in the rate sample, and congestion 1024 * control modules that define a cong_control function to run at the end 1025 * of ACK processing can optionally chose to consult this sample when 1026 * setting cwnd and pacing rate. 1027 * A sample is invalid if "delivered" or "interval_us" is negative. 1028 */ 1029 struct rate_sample { 1030 u64 prior_mstamp; /* starting timestamp for interval */ 1031 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1032 s32 delivered; /* number of packets delivered over interval */ 1033 long interval_us; /* time for tp->delivered to incr "delivered" */ 1034 u32 snd_interval_us; /* snd interval for delivered packets */ 1035 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1036 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1037 int losses; /* number of packets marked lost upon ACK */ 1038 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1039 u32 prior_in_flight; /* in flight before this ACK */ 1040 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1041 bool is_retrans; /* is sample from retransmission? */ 1042 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1043 }; 1044 1045 struct tcp_congestion_ops { 1046 /* fast path fields are put first to fill one cache line */ 1047 1048 /* return slow start threshold (required) */ 1049 u32 (*ssthresh)(struct sock *sk); 1050 1051 /* do new cwnd calculation (required) */ 1052 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1053 1054 /* call before changing ca_state (optional) */ 1055 void (*set_state)(struct sock *sk, u8 new_state); 1056 1057 /* call when cwnd event occurs (optional) */ 1058 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1059 1060 /* call when ack arrives (optional) */ 1061 void (*in_ack_event)(struct sock *sk, u32 flags); 1062 1063 /* hook for packet ack accounting (optional) */ 1064 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1065 1066 /* override sysctl_tcp_min_tso_segs */ 1067 u32 (*min_tso_segs)(struct sock *sk); 1068 1069 /* call when packets are delivered to update cwnd and pacing rate, 1070 * after all the ca_state processing. (optional) 1071 */ 1072 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1073 1074 1075 /* new value of cwnd after loss (required) */ 1076 u32 (*undo_cwnd)(struct sock *sk); 1077 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1078 u32 (*sndbuf_expand)(struct sock *sk); 1079 1080 /* control/slow paths put last */ 1081 /* get info for inet_diag (optional) */ 1082 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1083 union tcp_cc_info *info); 1084 1085 char name[TCP_CA_NAME_MAX]; 1086 struct module *owner; 1087 struct list_head list; 1088 u32 key; 1089 u32 flags; 1090 1091 /* initialize private data (optional) */ 1092 void (*init)(struct sock *sk); 1093 /* cleanup private data (optional) */ 1094 void (*release)(struct sock *sk); 1095 } ____cacheline_aligned_in_smp; 1096 1097 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1098 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1099 1100 void tcp_assign_congestion_control(struct sock *sk); 1101 void tcp_init_congestion_control(struct sock *sk); 1102 void tcp_cleanup_congestion_control(struct sock *sk); 1103 int tcp_set_default_congestion_control(struct net *net, const char *name); 1104 void tcp_get_default_congestion_control(struct net *net, char *name); 1105 void tcp_get_available_congestion_control(char *buf, size_t len); 1106 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1107 int tcp_set_allowed_congestion_control(char *allowed); 1108 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1109 bool cap_net_admin); 1110 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1111 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1112 1113 u32 tcp_reno_ssthresh(struct sock *sk); 1114 u32 tcp_reno_undo_cwnd(struct sock *sk); 1115 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1116 extern struct tcp_congestion_ops tcp_reno; 1117 1118 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1119 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1120 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1121 #ifdef CONFIG_INET 1122 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1123 #else 1124 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1125 { 1126 return NULL; 1127 } 1128 #endif 1129 1130 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1131 { 1132 const struct inet_connection_sock *icsk = inet_csk(sk); 1133 1134 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1135 } 1136 1137 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 1138 { 1139 struct inet_connection_sock *icsk = inet_csk(sk); 1140 1141 if (icsk->icsk_ca_ops->set_state) 1142 icsk->icsk_ca_ops->set_state(sk, ca_state); 1143 icsk->icsk_ca_state = ca_state; 1144 } 1145 1146 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1147 { 1148 const struct inet_connection_sock *icsk = inet_csk(sk); 1149 1150 if (icsk->icsk_ca_ops->cwnd_event) 1151 icsk->icsk_ca_ops->cwnd_event(sk, event); 1152 } 1153 1154 /* From tcp_rate.c */ 1155 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1156 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1157 struct rate_sample *rs); 1158 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1159 bool is_sack_reneg, struct rate_sample *rs); 1160 void tcp_rate_check_app_limited(struct sock *sk); 1161 1162 /* These functions determine how the current flow behaves in respect of SACK 1163 * handling. SACK is negotiated with the peer, and therefore it can vary 1164 * between different flows. 1165 * 1166 * tcp_is_sack - SACK enabled 1167 * tcp_is_reno - No SACK 1168 */ 1169 static inline int tcp_is_sack(const struct tcp_sock *tp) 1170 { 1171 return likely(tp->rx_opt.sack_ok); 1172 } 1173 1174 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1175 { 1176 return !tcp_is_sack(tp); 1177 } 1178 1179 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1180 { 1181 return tp->sacked_out + tp->lost_out; 1182 } 1183 1184 /* This determines how many packets are "in the network" to the best 1185 * of our knowledge. In many cases it is conservative, but where 1186 * detailed information is available from the receiver (via SACK 1187 * blocks etc.) we can make more aggressive calculations. 1188 * 1189 * Use this for decisions involving congestion control, use just 1190 * tp->packets_out to determine if the send queue is empty or not. 1191 * 1192 * Read this equation as: 1193 * 1194 * "Packets sent once on transmission queue" MINUS 1195 * "Packets left network, but not honestly ACKed yet" PLUS 1196 * "Packets fast retransmitted" 1197 */ 1198 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1199 { 1200 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1201 } 1202 1203 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1204 1205 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1206 { 1207 return tp->snd_cwnd < tp->snd_ssthresh; 1208 } 1209 1210 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1211 { 1212 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1213 } 1214 1215 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1216 { 1217 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1218 (1 << inet_csk(sk)->icsk_ca_state); 1219 } 1220 1221 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1222 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1223 * ssthresh. 1224 */ 1225 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1226 { 1227 const struct tcp_sock *tp = tcp_sk(sk); 1228 1229 if (tcp_in_cwnd_reduction(sk)) 1230 return tp->snd_ssthresh; 1231 else 1232 return max(tp->snd_ssthresh, 1233 ((tp->snd_cwnd >> 1) + 1234 (tp->snd_cwnd >> 2))); 1235 } 1236 1237 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1238 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1239 1240 void tcp_enter_cwr(struct sock *sk); 1241 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1242 1243 /* The maximum number of MSS of available cwnd for which TSO defers 1244 * sending if not using sysctl_tcp_tso_win_divisor. 1245 */ 1246 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1247 { 1248 return 3; 1249 } 1250 1251 /* Returns end sequence number of the receiver's advertised window */ 1252 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1253 { 1254 return tp->snd_una + tp->snd_wnd; 1255 } 1256 1257 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1258 * flexible approach. The RFC suggests cwnd should not be raised unless 1259 * it was fully used previously. And that's exactly what we do in 1260 * congestion avoidance mode. But in slow start we allow cwnd to grow 1261 * as long as the application has used half the cwnd. 1262 * Example : 1263 * cwnd is 10 (IW10), but application sends 9 frames. 1264 * We allow cwnd to reach 18 when all frames are ACKed. 1265 * This check is safe because it's as aggressive as slow start which already 1266 * risks 100% overshoot. The advantage is that we discourage application to 1267 * either send more filler packets or data to artificially blow up the cwnd 1268 * usage, and allow application-limited process to probe bw more aggressively. 1269 */ 1270 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1271 { 1272 const struct tcp_sock *tp = tcp_sk(sk); 1273 1274 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1275 if (tcp_in_slow_start(tp)) 1276 return tp->snd_cwnd < 2 * tp->max_packets_out; 1277 1278 return tp->is_cwnd_limited; 1279 } 1280 1281 /* BBR congestion control needs pacing. 1282 * Same remark for SO_MAX_PACING_RATE. 1283 * sch_fq packet scheduler is efficiently handling pacing, 1284 * but is not always installed/used. 1285 * Return true if TCP stack should pace packets itself. 1286 */ 1287 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1288 { 1289 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1290 } 1291 1292 /* Estimates in how many jiffies next packet for this flow can be sent. 1293 * Scheduling a retransmit timer too early would be silly. 1294 */ 1295 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1296 { 1297 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1298 1299 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1300 } 1301 1302 static inline void tcp_reset_xmit_timer(struct sock *sk, 1303 const int what, 1304 unsigned long when, 1305 const unsigned long max_when) 1306 { 1307 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk), 1308 max_when); 1309 } 1310 1311 /* Something is really bad, we could not queue an additional packet, 1312 * because qdisc is full or receiver sent a 0 window, or we are paced. 1313 * We do not want to add fuel to the fire, or abort too early, 1314 * so make sure the timer we arm now is at least 200ms in the future, 1315 * regardless of current icsk_rto value (as it could be ~2ms) 1316 */ 1317 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1318 { 1319 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1320 } 1321 1322 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1323 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1324 unsigned long max_when) 1325 { 1326 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1327 inet_csk(sk)->icsk_backoff); 1328 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1329 1330 return (unsigned long)min_t(u64, when, max_when); 1331 } 1332 1333 static inline void tcp_check_probe_timer(struct sock *sk) 1334 { 1335 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1336 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1337 tcp_probe0_base(sk), TCP_RTO_MAX); 1338 } 1339 1340 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1341 { 1342 tp->snd_wl1 = seq; 1343 } 1344 1345 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1346 { 1347 tp->snd_wl1 = seq; 1348 } 1349 1350 /* 1351 * Calculate(/check) TCP checksum 1352 */ 1353 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1354 __be32 daddr, __wsum base) 1355 { 1356 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1357 } 1358 1359 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1360 { 1361 return !skb_csum_unnecessary(skb) && 1362 __skb_checksum_complete(skb); 1363 } 1364 1365 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); 1366 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1367 void tcp_set_state(struct sock *sk, int state); 1368 void tcp_done(struct sock *sk); 1369 int tcp_abort(struct sock *sk, int err); 1370 1371 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1372 { 1373 rx_opt->dsack = 0; 1374 rx_opt->num_sacks = 0; 1375 } 1376 1377 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1378 1379 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1380 { 1381 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1382 struct tcp_sock *tp = tcp_sk(sk); 1383 s32 delta; 1384 1385 if (!sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle || tp->packets_out || 1386 ca_ops->cong_control) 1387 return; 1388 delta = tcp_jiffies32 - tp->lsndtime; 1389 if (delta > inet_csk(sk)->icsk_rto) 1390 tcp_cwnd_restart(sk, delta); 1391 } 1392 1393 /* Determine a window scaling and initial window to offer. */ 1394 void tcp_select_initial_window(const struct sock *sk, int __space, 1395 __u32 mss, __u32 *rcv_wnd, 1396 __u32 *window_clamp, int wscale_ok, 1397 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1398 1399 static inline int tcp_win_from_space(const struct sock *sk, int space) 1400 { 1401 int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; 1402 1403 return tcp_adv_win_scale <= 0 ? 1404 (space>>(-tcp_adv_win_scale)) : 1405 space - (space>>tcp_adv_win_scale); 1406 } 1407 1408 /* Note: caller must be prepared to deal with negative returns */ 1409 static inline int tcp_space(const struct sock *sk) 1410 { 1411 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1412 READ_ONCE(sk->sk_backlog.len) - 1413 atomic_read(&sk->sk_rmem_alloc)); 1414 } 1415 1416 static inline int tcp_full_space(const struct sock *sk) 1417 { 1418 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1419 } 1420 1421 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1422 1423 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1424 * If 87.5 % (7/8) of the space has been consumed, we want to override 1425 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1426 * len/truesize ratio. 1427 */ 1428 static inline bool tcp_rmem_pressure(const struct sock *sk) 1429 { 1430 int rcvbuf, threshold; 1431 1432 if (tcp_under_memory_pressure(sk)) 1433 return true; 1434 1435 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1436 threshold = rcvbuf - (rcvbuf >> 3); 1437 1438 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1439 } 1440 1441 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1442 { 1443 const struct tcp_sock *tp = tcp_sk(sk); 1444 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1445 1446 if (avail <= 0) 1447 return false; 1448 1449 return (avail >= target) || tcp_rmem_pressure(sk) || 1450 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1451 } 1452 1453 extern void tcp_openreq_init_rwin(struct request_sock *req, 1454 const struct sock *sk_listener, 1455 const struct dst_entry *dst); 1456 1457 void tcp_enter_memory_pressure(struct sock *sk); 1458 void tcp_leave_memory_pressure(struct sock *sk); 1459 1460 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1461 { 1462 struct net *net = sock_net((struct sock *)tp); 1463 1464 return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl; 1465 } 1466 1467 static inline int keepalive_time_when(const struct tcp_sock *tp) 1468 { 1469 struct net *net = sock_net((struct sock *)tp); 1470 1471 return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time; 1472 } 1473 1474 static inline int keepalive_probes(const struct tcp_sock *tp) 1475 { 1476 struct net *net = sock_net((struct sock *)tp); 1477 1478 return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes; 1479 } 1480 1481 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1482 { 1483 const struct inet_connection_sock *icsk = &tp->inet_conn; 1484 1485 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1486 tcp_jiffies32 - tp->rcv_tstamp); 1487 } 1488 1489 static inline int tcp_fin_time(const struct sock *sk) 1490 { 1491 int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout; 1492 const int rto = inet_csk(sk)->icsk_rto; 1493 1494 if (fin_timeout < (rto << 2) - (rto >> 1)) 1495 fin_timeout = (rto << 2) - (rto >> 1); 1496 1497 return fin_timeout; 1498 } 1499 1500 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1501 int paws_win) 1502 { 1503 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1504 return true; 1505 if (unlikely(!time_before32(ktime_get_seconds(), 1506 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1507 return true; 1508 /* 1509 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1510 * then following tcp messages have valid values. Ignore 0 value, 1511 * or else 'negative' tsval might forbid us to accept their packets. 1512 */ 1513 if (!rx_opt->ts_recent) 1514 return true; 1515 return false; 1516 } 1517 1518 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1519 int rst) 1520 { 1521 if (tcp_paws_check(rx_opt, 0)) 1522 return false; 1523 1524 /* RST segments are not recommended to carry timestamp, 1525 and, if they do, it is recommended to ignore PAWS because 1526 "their cleanup function should take precedence over timestamps." 1527 Certainly, it is mistake. It is necessary to understand the reasons 1528 of this constraint to relax it: if peer reboots, clock may go 1529 out-of-sync and half-open connections will not be reset. 1530 Actually, the problem would be not existing if all 1531 the implementations followed draft about maintaining clock 1532 via reboots. Linux-2.2 DOES NOT! 1533 1534 However, we can relax time bounds for RST segments to MSL. 1535 */ 1536 if (rst && !time_before32(ktime_get_seconds(), 1537 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1538 return false; 1539 return true; 1540 } 1541 1542 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1543 int mib_idx, u32 *last_oow_ack_time); 1544 1545 static inline void tcp_mib_init(struct net *net) 1546 { 1547 /* See RFC 2012 */ 1548 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1549 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1550 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1551 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1552 } 1553 1554 /* from STCP */ 1555 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1556 { 1557 tp->lost_skb_hint = NULL; 1558 } 1559 1560 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1561 { 1562 tcp_clear_retrans_hints_partial(tp); 1563 tp->retransmit_skb_hint = NULL; 1564 } 1565 1566 union tcp_md5_addr { 1567 struct in_addr a4; 1568 #if IS_ENABLED(CONFIG_IPV6) 1569 struct in6_addr a6; 1570 #endif 1571 }; 1572 1573 /* - key database */ 1574 struct tcp_md5sig_key { 1575 struct hlist_node node; 1576 u8 keylen; 1577 u8 family; /* AF_INET or AF_INET6 */ 1578 u8 prefixlen; 1579 union tcp_md5_addr addr; 1580 int l3index; /* set if key added with L3 scope */ 1581 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1582 struct rcu_head rcu; 1583 }; 1584 1585 /* - sock block */ 1586 struct tcp_md5sig_info { 1587 struct hlist_head head; 1588 struct rcu_head rcu; 1589 }; 1590 1591 /* - pseudo header */ 1592 struct tcp4_pseudohdr { 1593 __be32 saddr; 1594 __be32 daddr; 1595 __u8 pad; 1596 __u8 protocol; 1597 __be16 len; 1598 }; 1599 1600 struct tcp6_pseudohdr { 1601 struct in6_addr saddr; 1602 struct in6_addr daddr; 1603 __be32 len; 1604 __be32 protocol; /* including padding */ 1605 }; 1606 1607 union tcp_md5sum_block { 1608 struct tcp4_pseudohdr ip4; 1609 #if IS_ENABLED(CONFIG_IPV6) 1610 struct tcp6_pseudohdr ip6; 1611 #endif 1612 }; 1613 1614 /* - pool: digest algorithm, hash description and scratch buffer */ 1615 struct tcp_md5sig_pool { 1616 struct ahash_request *md5_req; 1617 void *scratch; 1618 }; 1619 1620 /* - functions */ 1621 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1622 const struct sock *sk, const struct sk_buff *skb); 1623 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1624 int family, u8 prefixlen, int l3index, 1625 const u8 *newkey, u8 newkeylen, gfp_t gfp); 1626 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1627 int family, u8 prefixlen, int l3index); 1628 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1629 const struct sock *addr_sk); 1630 1631 #ifdef CONFIG_TCP_MD5SIG 1632 #include <linux/jump_label.h> 1633 extern struct static_key_false tcp_md5_needed; 1634 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1635 const union tcp_md5_addr *addr, 1636 int family); 1637 static inline struct tcp_md5sig_key * 1638 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1639 const union tcp_md5_addr *addr, int family) 1640 { 1641 if (!static_branch_unlikely(&tcp_md5_needed)) 1642 return NULL; 1643 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1644 } 1645 1646 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1647 #else 1648 static inline struct tcp_md5sig_key * 1649 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1650 const union tcp_md5_addr *addr, int family) 1651 { 1652 return NULL; 1653 } 1654 #define tcp_twsk_md5_key(twsk) NULL 1655 #endif 1656 1657 bool tcp_alloc_md5sig_pool(void); 1658 1659 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1660 static inline void tcp_put_md5sig_pool(void) 1661 { 1662 local_bh_enable(); 1663 } 1664 1665 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1666 unsigned int header_len); 1667 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1668 const struct tcp_md5sig_key *key); 1669 1670 /* From tcp_fastopen.c */ 1671 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1672 struct tcp_fastopen_cookie *cookie); 1673 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1674 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1675 u16 try_exp); 1676 struct tcp_fastopen_request { 1677 /* Fast Open cookie. Size 0 means a cookie request */ 1678 struct tcp_fastopen_cookie cookie; 1679 struct msghdr *data; /* data in MSG_FASTOPEN */ 1680 size_t size; 1681 int copied; /* queued in tcp_connect() */ 1682 struct ubuf_info *uarg; 1683 }; 1684 void tcp_free_fastopen_req(struct tcp_sock *tp); 1685 void tcp_fastopen_destroy_cipher(struct sock *sk); 1686 void tcp_fastopen_ctx_destroy(struct net *net); 1687 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1688 void *primary_key, void *backup_key); 1689 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1690 u64 *key); 1691 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1692 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1693 struct request_sock *req, 1694 struct tcp_fastopen_cookie *foc, 1695 const struct dst_entry *dst); 1696 void tcp_fastopen_init_key_once(struct net *net); 1697 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1698 struct tcp_fastopen_cookie *cookie); 1699 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1700 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1701 #define TCP_FASTOPEN_KEY_MAX 2 1702 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1703 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1704 1705 /* Fastopen key context */ 1706 struct tcp_fastopen_context { 1707 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1708 int num; 1709 struct rcu_head rcu; 1710 }; 1711 1712 void tcp_fastopen_active_disable(struct sock *sk); 1713 bool tcp_fastopen_active_should_disable(struct sock *sk); 1714 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1715 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1716 1717 /* Caller needs to wrap with rcu_read_(un)lock() */ 1718 static inline 1719 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1720 { 1721 struct tcp_fastopen_context *ctx; 1722 1723 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1724 if (!ctx) 1725 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1726 return ctx; 1727 } 1728 1729 static inline 1730 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1731 const struct tcp_fastopen_cookie *orig) 1732 { 1733 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1734 orig->len == foc->len && 1735 !memcmp(orig->val, foc->val, foc->len)) 1736 return true; 1737 return false; 1738 } 1739 1740 static inline 1741 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1742 { 1743 return ctx->num; 1744 } 1745 1746 /* Latencies incurred by various limits for a sender. They are 1747 * chronograph-like stats that are mutually exclusive. 1748 */ 1749 enum tcp_chrono { 1750 TCP_CHRONO_UNSPEC, 1751 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1752 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1753 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1754 __TCP_CHRONO_MAX, 1755 }; 1756 1757 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1758 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1759 1760 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1761 * the same memory storage than skb->destructor/_skb_refdst 1762 */ 1763 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1764 { 1765 skb->destructor = NULL; 1766 skb->_skb_refdst = 0UL; 1767 } 1768 1769 #define tcp_skb_tsorted_save(skb) { \ 1770 unsigned long _save = skb->_skb_refdst; \ 1771 skb->_skb_refdst = 0UL; 1772 1773 #define tcp_skb_tsorted_restore(skb) \ 1774 skb->_skb_refdst = _save; \ 1775 } 1776 1777 void tcp_write_queue_purge(struct sock *sk); 1778 1779 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1780 { 1781 return skb_rb_first(&sk->tcp_rtx_queue); 1782 } 1783 1784 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1785 { 1786 return skb_rb_last(&sk->tcp_rtx_queue); 1787 } 1788 1789 static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) 1790 { 1791 return skb_peek(&sk->sk_write_queue); 1792 } 1793 1794 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1795 { 1796 return skb_peek_tail(&sk->sk_write_queue); 1797 } 1798 1799 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1800 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1801 1802 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1803 { 1804 return skb_peek(&sk->sk_write_queue); 1805 } 1806 1807 static inline bool tcp_skb_is_last(const struct sock *sk, 1808 const struct sk_buff *skb) 1809 { 1810 return skb_queue_is_last(&sk->sk_write_queue, skb); 1811 } 1812 1813 /** 1814 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1815 * @sk: socket 1816 * 1817 * Since the write queue can have a temporary empty skb in it, 1818 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1819 */ 1820 static inline bool tcp_write_queue_empty(const struct sock *sk) 1821 { 1822 const struct tcp_sock *tp = tcp_sk(sk); 1823 1824 return tp->write_seq == tp->snd_nxt; 1825 } 1826 1827 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1828 { 1829 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1830 } 1831 1832 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1833 { 1834 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1835 } 1836 1837 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1838 { 1839 __skb_queue_tail(&sk->sk_write_queue, skb); 1840 1841 /* Queue it, remembering where we must start sending. */ 1842 if (sk->sk_write_queue.next == skb) 1843 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1844 } 1845 1846 /* Insert new before skb on the write queue of sk. */ 1847 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1848 struct sk_buff *skb, 1849 struct sock *sk) 1850 { 1851 __skb_queue_before(&sk->sk_write_queue, skb, new); 1852 } 1853 1854 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1855 { 1856 tcp_skb_tsorted_anchor_cleanup(skb); 1857 __skb_unlink(skb, &sk->sk_write_queue); 1858 } 1859 1860 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1861 1862 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1863 { 1864 tcp_skb_tsorted_anchor_cleanup(skb); 1865 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1866 } 1867 1868 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1869 { 1870 list_del(&skb->tcp_tsorted_anchor); 1871 tcp_rtx_queue_unlink(skb, sk); 1872 sk_wmem_free_skb(sk, skb); 1873 } 1874 1875 static inline void tcp_push_pending_frames(struct sock *sk) 1876 { 1877 if (tcp_send_head(sk)) { 1878 struct tcp_sock *tp = tcp_sk(sk); 1879 1880 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1881 } 1882 } 1883 1884 /* Start sequence of the skb just after the highest skb with SACKed 1885 * bit, valid only if sacked_out > 0 or when the caller has ensured 1886 * validity by itself. 1887 */ 1888 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1889 { 1890 if (!tp->sacked_out) 1891 return tp->snd_una; 1892 1893 if (tp->highest_sack == NULL) 1894 return tp->snd_nxt; 1895 1896 return TCP_SKB_CB(tp->highest_sack)->seq; 1897 } 1898 1899 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1900 { 1901 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 1902 } 1903 1904 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1905 { 1906 return tcp_sk(sk)->highest_sack; 1907 } 1908 1909 static inline void tcp_highest_sack_reset(struct sock *sk) 1910 { 1911 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 1912 } 1913 1914 /* Called when old skb is about to be deleted and replaced by new skb */ 1915 static inline void tcp_highest_sack_replace(struct sock *sk, 1916 struct sk_buff *old, 1917 struct sk_buff *new) 1918 { 1919 if (old == tcp_highest_sack(sk)) 1920 tcp_sk(sk)->highest_sack = new; 1921 } 1922 1923 /* This helper checks if socket has IP_TRANSPARENT set */ 1924 static inline bool inet_sk_transparent(const struct sock *sk) 1925 { 1926 switch (sk->sk_state) { 1927 case TCP_TIME_WAIT: 1928 return inet_twsk(sk)->tw_transparent; 1929 case TCP_NEW_SYN_RECV: 1930 return inet_rsk(inet_reqsk(sk))->no_srccheck; 1931 } 1932 return inet_sk(sk)->transparent; 1933 } 1934 1935 /* Determines whether this is a thin stream (which may suffer from 1936 * increased latency). Used to trigger latency-reducing mechanisms. 1937 */ 1938 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 1939 { 1940 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 1941 } 1942 1943 /* /proc */ 1944 enum tcp_seq_states { 1945 TCP_SEQ_STATE_LISTENING, 1946 TCP_SEQ_STATE_ESTABLISHED, 1947 }; 1948 1949 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 1950 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 1951 void tcp_seq_stop(struct seq_file *seq, void *v); 1952 1953 struct tcp_seq_afinfo { 1954 sa_family_t family; 1955 }; 1956 1957 struct tcp_iter_state { 1958 struct seq_net_private p; 1959 enum tcp_seq_states state; 1960 struct sock *syn_wait_sk; 1961 struct tcp_seq_afinfo *bpf_seq_afinfo; 1962 int bucket, offset, sbucket, num; 1963 loff_t last_pos; 1964 }; 1965 1966 extern struct request_sock_ops tcp_request_sock_ops; 1967 extern struct request_sock_ops tcp6_request_sock_ops; 1968 1969 void tcp_v4_destroy_sock(struct sock *sk); 1970 1971 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 1972 netdev_features_t features); 1973 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 1974 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 1975 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 1976 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 1977 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 1978 int tcp_gro_complete(struct sk_buff *skb); 1979 1980 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 1981 1982 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 1983 { 1984 struct net *net = sock_net((struct sock *)tp); 1985 return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat; 1986 } 1987 1988 bool tcp_stream_memory_free(const struct sock *sk, int wake); 1989 1990 #ifdef CONFIG_PROC_FS 1991 int tcp4_proc_init(void); 1992 void tcp4_proc_exit(void); 1993 #endif 1994 1995 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 1996 int tcp_conn_request(struct request_sock_ops *rsk_ops, 1997 const struct tcp_request_sock_ops *af_ops, 1998 struct sock *sk, struct sk_buff *skb); 1999 2000 /* TCP af-specific functions */ 2001 struct tcp_sock_af_ops { 2002 #ifdef CONFIG_TCP_MD5SIG 2003 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2004 const struct sock *addr_sk); 2005 int (*calc_md5_hash)(char *location, 2006 const struct tcp_md5sig_key *md5, 2007 const struct sock *sk, 2008 const struct sk_buff *skb); 2009 int (*md5_parse)(struct sock *sk, 2010 int optname, 2011 sockptr_t optval, 2012 int optlen); 2013 #endif 2014 }; 2015 2016 struct tcp_request_sock_ops { 2017 u16 mss_clamp; 2018 #ifdef CONFIG_TCP_MD5SIG 2019 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2020 const struct sock *addr_sk); 2021 int (*calc_md5_hash) (char *location, 2022 const struct tcp_md5sig_key *md5, 2023 const struct sock *sk, 2024 const struct sk_buff *skb); 2025 #endif 2026 #ifdef CONFIG_SYN_COOKIES 2027 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2028 __u16 *mss); 2029 #endif 2030 struct dst_entry *(*route_req)(const struct sock *sk, 2031 struct sk_buff *skb, 2032 struct flowi *fl, 2033 struct request_sock *req); 2034 u32 (*init_seq)(const struct sk_buff *skb); 2035 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2036 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2037 struct flowi *fl, struct request_sock *req, 2038 struct tcp_fastopen_cookie *foc, 2039 enum tcp_synack_type synack_type, 2040 struct sk_buff *syn_skb); 2041 }; 2042 2043 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2044 #if IS_ENABLED(CONFIG_IPV6) 2045 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2046 #endif 2047 2048 #ifdef CONFIG_SYN_COOKIES 2049 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2050 const struct sock *sk, struct sk_buff *skb, 2051 __u16 *mss) 2052 { 2053 tcp_synq_overflow(sk); 2054 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2055 return ops->cookie_init_seq(skb, mss); 2056 } 2057 #else 2058 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2059 const struct sock *sk, struct sk_buff *skb, 2060 __u16 *mss) 2061 { 2062 return 0; 2063 } 2064 #endif 2065 2066 int tcpv4_offload_init(void); 2067 2068 void tcp_v4_init(void); 2069 void tcp_init(void); 2070 2071 /* tcp_recovery.c */ 2072 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2073 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2074 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2075 u32 reo_wnd); 2076 extern bool tcp_rack_mark_lost(struct sock *sk); 2077 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2078 u64 xmit_time); 2079 extern void tcp_rack_reo_timeout(struct sock *sk); 2080 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2081 2082 /* At how many usecs into the future should the RTO fire? */ 2083 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2084 { 2085 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2086 u32 rto = inet_csk(sk)->icsk_rto; 2087 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2088 2089 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2090 } 2091 2092 /* 2093 * Save and compile IPv4 options, return a pointer to it 2094 */ 2095 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2096 struct sk_buff *skb) 2097 { 2098 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2099 struct ip_options_rcu *dopt = NULL; 2100 2101 if (opt->optlen) { 2102 int opt_size = sizeof(*dopt) + opt->optlen; 2103 2104 dopt = kmalloc(opt_size, GFP_ATOMIC); 2105 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2106 kfree(dopt); 2107 dopt = NULL; 2108 } 2109 } 2110 return dopt; 2111 } 2112 2113 /* locally generated TCP pure ACKs have skb->truesize == 2 2114 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2115 * This is much faster than dissecting the packet to find out. 2116 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2117 */ 2118 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2119 { 2120 return skb->truesize == 2; 2121 } 2122 2123 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2124 { 2125 skb->truesize = 2; 2126 } 2127 2128 static inline int tcp_inq(struct sock *sk) 2129 { 2130 struct tcp_sock *tp = tcp_sk(sk); 2131 int answ; 2132 2133 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2134 answ = 0; 2135 } else if (sock_flag(sk, SOCK_URGINLINE) || 2136 !tp->urg_data || 2137 before(tp->urg_seq, tp->copied_seq) || 2138 !before(tp->urg_seq, tp->rcv_nxt)) { 2139 2140 answ = tp->rcv_nxt - tp->copied_seq; 2141 2142 /* Subtract 1, if FIN was received */ 2143 if (answ && sock_flag(sk, SOCK_DONE)) 2144 answ--; 2145 } else { 2146 answ = tp->urg_seq - tp->copied_seq; 2147 } 2148 2149 return answ; 2150 } 2151 2152 int tcp_peek_len(struct socket *sock); 2153 2154 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2155 { 2156 u16 segs_in; 2157 2158 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2159 tp->segs_in += segs_in; 2160 if (skb->len > tcp_hdrlen(skb)) 2161 tp->data_segs_in += segs_in; 2162 } 2163 2164 /* 2165 * TCP listen path runs lockless. 2166 * We forced "struct sock" to be const qualified to make sure 2167 * we don't modify one of its field by mistake. 2168 * Here, we increment sk_drops which is an atomic_t, so we can safely 2169 * make sock writable again. 2170 */ 2171 static inline void tcp_listendrop(const struct sock *sk) 2172 { 2173 atomic_inc(&((struct sock *)sk)->sk_drops); 2174 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2175 } 2176 2177 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2178 2179 /* 2180 * Interface for adding Upper Level Protocols over TCP 2181 */ 2182 2183 #define TCP_ULP_NAME_MAX 16 2184 #define TCP_ULP_MAX 128 2185 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2186 2187 struct tcp_ulp_ops { 2188 struct list_head list; 2189 2190 /* initialize ulp */ 2191 int (*init)(struct sock *sk); 2192 /* update ulp */ 2193 void (*update)(struct sock *sk, struct proto *p, 2194 void (*write_space)(struct sock *sk)); 2195 /* cleanup ulp */ 2196 void (*release)(struct sock *sk); 2197 /* diagnostic */ 2198 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2199 size_t (*get_info_size)(const struct sock *sk); 2200 /* clone ulp */ 2201 void (*clone)(const struct request_sock *req, struct sock *newsk, 2202 const gfp_t priority); 2203 2204 char name[TCP_ULP_NAME_MAX]; 2205 struct module *owner; 2206 }; 2207 int tcp_register_ulp(struct tcp_ulp_ops *type); 2208 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2209 int tcp_set_ulp(struct sock *sk, const char *name); 2210 void tcp_get_available_ulp(char *buf, size_t len); 2211 void tcp_cleanup_ulp(struct sock *sk); 2212 void tcp_update_ulp(struct sock *sk, struct proto *p, 2213 void (*write_space)(struct sock *sk)); 2214 2215 #define MODULE_ALIAS_TCP_ULP(name) \ 2216 __MODULE_INFO(alias, alias_userspace, name); \ 2217 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2218 2219 #ifdef CONFIG_NET_SOCK_MSG 2220 struct sk_msg; 2221 struct sk_psock; 2222 2223 #ifdef CONFIG_BPF_SYSCALL 2224 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 2225 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2226 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2227 #endif /* CONFIG_BPF_SYSCALL */ 2228 2229 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes, 2230 int flags); 2231 #endif /* CONFIG_NET_SOCK_MSG */ 2232 2233 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2234 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2235 { 2236 } 2237 #endif 2238 2239 #ifdef CONFIG_CGROUP_BPF 2240 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2241 struct sk_buff *skb, 2242 unsigned int end_offset) 2243 { 2244 skops->skb = skb; 2245 skops->skb_data_end = skb->data + end_offset; 2246 } 2247 #else 2248 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2249 struct sk_buff *skb, 2250 unsigned int end_offset) 2251 { 2252 } 2253 #endif 2254 2255 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2256 * is < 0, then the BPF op failed (for example if the loaded BPF 2257 * program does not support the chosen operation or there is no BPF 2258 * program loaded). 2259 */ 2260 #ifdef CONFIG_BPF 2261 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2262 { 2263 struct bpf_sock_ops_kern sock_ops; 2264 int ret; 2265 2266 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2267 if (sk_fullsock(sk)) { 2268 sock_ops.is_fullsock = 1; 2269 sock_owned_by_me(sk); 2270 } 2271 2272 sock_ops.sk = sk; 2273 sock_ops.op = op; 2274 if (nargs > 0) 2275 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2276 2277 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2278 if (ret == 0) 2279 ret = sock_ops.reply; 2280 else 2281 ret = -1; 2282 return ret; 2283 } 2284 2285 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2286 { 2287 u32 args[2] = {arg1, arg2}; 2288 2289 return tcp_call_bpf(sk, op, 2, args); 2290 } 2291 2292 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2293 u32 arg3) 2294 { 2295 u32 args[3] = {arg1, arg2, arg3}; 2296 2297 return tcp_call_bpf(sk, op, 3, args); 2298 } 2299 2300 #else 2301 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2302 { 2303 return -EPERM; 2304 } 2305 2306 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2307 { 2308 return -EPERM; 2309 } 2310 2311 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2312 u32 arg3) 2313 { 2314 return -EPERM; 2315 } 2316 2317 #endif 2318 2319 static inline u32 tcp_timeout_init(struct sock *sk) 2320 { 2321 int timeout; 2322 2323 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2324 2325 if (timeout <= 0) 2326 timeout = TCP_TIMEOUT_INIT; 2327 return timeout; 2328 } 2329 2330 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2331 { 2332 int rwnd; 2333 2334 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2335 2336 if (rwnd < 0) 2337 rwnd = 0; 2338 return rwnd; 2339 } 2340 2341 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2342 { 2343 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2344 } 2345 2346 static inline void tcp_bpf_rtt(struct sock *sk) 2347 { 2348 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2349 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2350 } 2351 2352 #if IS_ENABLED(CONFIG_SMC) 2353 extern struct static_key_false tcp_have_smc; 2354 #endif 2355 2356 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2357 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2358 void (*cad)(struct sock *sk, u32 ack_seq)); 2359 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2360 void clean_acked_data_flush(void); 2361 #endif 2362 2363 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2364 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2365 const struct tcp_sock *tp) 2366 { 2367 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2368 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2369 } 2370 2371 /* Compute Earliest Departure Time for some control packets 2372 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2373 */ 2374 static inline u64 tcp_transmit_time(const struct sock *sk) 2375 { 2376 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2377 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2378 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2379 2380 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2381 } 2382 return 0; 2383 } 2384 2385 #endif /* _TCP_H */ 2386