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