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