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 struct { 887 __u32 flags; 888 struct sock *sk_redir; 889 void *data_end; 890 } bpf; 891 }; 892 }; 893 894 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 895 896 static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb) 897 { 898 TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb); 899 } 900 901 static inline bool tcp_skb_bpf_ingress(const struct sk_buff *skb) 902 { 903 return TCP_SKB_CB(skb)->bpf.flags & BPF_F_INGRESS; 904 } 905 906 static inline struct sock *tcp_skb_bpf_redirect_fetch(struct sk_buff *skb) 907 { 908 return TCP_SKB_CB(skb)->bpf.sk_redir; 909 } 910 911 static inline void tcp_skb_bpf_redirect_clear(struct sk_buff *skb) 912 { 913 TCP_SKB_CB(skb)->bpf.sk_redir = NULL; 914 } 915 916 extern const struct inet_connection_sock_af_ops ipv4_specific; 917 918 #if IS_ENABLED(CONFIG_IPV6) 919 /* This is the variant of inet6_iif() that must be used by TCP, 920 * as TCP moves IP6CB into a different location in skb->cb[] 921 */ 922 static inline int tcp_v6_iif(const struct sk_buff *skb) 923 { 924 return TCP_SKB_CB(skb)->header.h6.iif; 925 } 926 927 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 928 { 929 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 930 931 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 932 } 933 934 /* TCP_SKB_CB reference means this can not be used from early demux */ 935 static inline int tcp_v6_sdif(const struct sk_buff *skb) 936 { 937 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 938 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 939 return TCP_SKB_CB(skb)->header.h6.iif; 940 #endif 941 return 0; 942 } 943 944 extern const struct inet_connection_sock_af_ops ipv6_specific; 945 946 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 947 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 948 INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *skb)); 949 950 #endif 951 952 /* TCP_SKB_CB reference means this can not be used from early demux */ 953 static inline int tcp_v4_sdif(struct sk_buff *skb) 954 { 955 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 956 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 957 return TCP_SKB_CB(skb)->header.h4.iif; 958 #endif 959 return 0; 960 } 961 962 /* Due to TSO, an SKB can be composed of multiple actual 963 * packets. To keep these tracked properly, we use this. 964 */ 965 static inline int tcp_skb_pcount(const struct sk_buff *skb) 966 { 967 return TCP_SKB_CB(skb)->tcp_gso_segs; 968 } 969 970 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 971 { 972 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 973 } 974 975 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 976 { 977 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 978 } 979 980 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 981 static inline int tcp_skb_mss(const struct sk_buff *skb) 982 { 983 return TCP_SKB_CB(skb)->tcp_gso_size; 984 } 985 986 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 987 { 988 return likely(!TCP_SKB_CB(skb)->eor); 989 } 990 991 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 992 const struct sk_buff *from) 993 { 994 return likely(tcp_skb_can_collapse_to(to) && 995 mptcp_skb_can_collapse(to, from)); 996 } 997 998 /* Events passed to congestion control interface */ 999 enum tcp_ca_event { 1000 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 1001 CA_EVENT_CWND_RESTART, /* congestion window restart */ 1002 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 1003 CA_EVENT_LOSS, /* loss timeout */ 1004 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 1005 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 1006 }; 1007 1008 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1009 enum tcp_ca_ack_event_flags { 1010 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1011 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1012 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1013 }; 1014 1015 /* 1016 * Interface for adding new TCP congestion control handlers 1017 */ 1018 #define TCP_CA_NAME_MAX 16 1019 #define TCP_CA_MAX 128 1020 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1021 1022 #define TCP_CA_UNSPEC 0 1023 1024 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1025 #define TCP_CONG_NON_RESTRICTED 0x1 1026 /* Requires ECN/ECT set on all packets */ 1027 #define TCP_CONG_NEEDS_ECN 0x2 1028 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1029 1030 union tcp_cc_info; 1031 1032 struct ack_sample { 1033 u32 pkts_acked; 1034 s32 rtt_us; 1035 u32 in_flight; 1036 }; 1037 1038 /* A rate sample measures the number of (original/retransmitted) data 1039 * packets delivered "delivered" over an interval of time "interval_us". 1040 * The tcp_rate.c code fills in the rate sample, and congestion 1041 * control modules that define a cong_control function to run at the end 1042 * of ACK processing can optionally chose to consult this sample when 1043 * setting cwnd and pacing rate. 1044 * A sample is invalid if "delivered" or "interval_us" is negative. 1045 */ 1046 struct rate_sample { 1047 u64 prior_mstamp; /* starting timestamp for interval */ 1048 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1049 s32 delivered; /* number of packets delivered over interval */ 1050 long interval_us; /* time for tp->delivered to incr "delivered" */ 1051 u32 snd_interval_us; /* snd interval for delivered packets */ 1052 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1053 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1054 int losses; /* number of packets marked lost upon ACK */ 1055 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1056 u32 prior_in_flight; /* in flight before this ACK */ 1057 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1058 bool is_retrans; /* is sample from retransmission? */ 1059 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1060 }; 1061 1062 struct tcp_congestion_ops { 1063 struct list_head list; 1064 u32 key; 1065 u32 flags; 1066 1067 /* initialize private data (optional) */ 1068 void (*init)(struct sock *sk); 1069 /* cleanup private data (optional) */ 1070 void (*release)(struct sock *sk); 1071 1072 /* return slow start threshold (required) */ 1073 u32 (*ssthresh)(struct sock *sk); 1074 /* do new cwnd calculation (required) */ 1075 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1076 /* call before changing ca_state (optional) */ 1077 void (*set_state)(struct sock *sk, u8 new_state); 1078 /* call when cwnd event occurs (optional) */ 1079 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1080 /* call when ack arrives (optional) */ 1081 void (*in_ack_event)(struct sock *sk, u32 flags); 1082 /* new value of cwnd after loss (required) */ 1083 u32 (*undo_cwnd)(struct sock *sk); 1084 /* hook for packet ack accounting (optional) */ 1085 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1086 /* override sysctl_tcp_min_tso_segs */ 1087 u32 (*min_tso_segs)(struct sock *sk); 1088 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1089 u32 (*sndbuf_expand)(struct sock *sk); 1090 /* call when packets are delivered to update cwnd and pacing rate, 1091 * after all the ca_state processing. (optional) 1092 */ 1093 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1094 /* get info for inet_diag (optional) */ 1095 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1096 union tcp_cc_info *info); 1097 1098 char name[TCP_CA_NAME_MAX]; 1099 struct module *owner; 1100 }; 1101 1102 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1103 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1104 1105 void tcp_assign_congestion_control(struct sock *sk); 1106 void tcp_init_congestion_control(struct sock *sk); 1107 void tcp_cleanup_congestion_control(struct sock *sk); 1108 int tcp_set_default_congestion_control(struct net *net, const char *name); 1109 void tcp_get_default_congestion_control(struct net *net, char *name); 1110 void tcp_get_available_congestion_control(char *buf, size_t len); 1111 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1112 int tcp_set_allowed_congestion_control(char *allowed); 1113 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1114 bool cap_net_admin); 1115 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1116 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1117 1118 u32 tcp_reno_ssthresh(struct sock *sk); 1119 u32 tcp_reno_undo_cwnd(struct sock *sk); 1120 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1121 extern struct tcp_congestion_ops tcp_reno; 1122 1123 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1124 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1125 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1126 #ifdef CONFIG_INET 1127 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1128 #else 1129 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1130 { 1131 return NULL; 1132 } 1133 #endif 1134 1135 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1136 { 1137 const struct inet_connection_sock *icsk = inet_csk(sk); 1138 1139 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1140 } 1141 1142 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 1143 { 1144 struct inet_connection_sock *icsk = inet_csk(sk); 1145 1146 if (icsk->icsk_ca_ops->set_state) 1147 icsk->icsk_ca_ops->set_state(sk, ca_state); 1148 icsk->icsk_ca_state = ca_state; 1149 } 1150 1151 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1152 { 1153 const struct inet_connection_sock *icsk = inet_csk(sk); 1154 1155 if (icsk->icsk_ca_ops->cwnd_event) 1156 icsk->icsk_ca_ops->cwnd_event(sk, event); 1157 } 1158 1159 /* From tcp_rate.c */ 1160 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1161 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1162 struct rate_sample *rs); 1163 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1164 bool is_sack_reneg, struct rate_sample *rs); 1165 void tcp_rate_check_app_limited(struct sock *sk); 1166 1167 /* These functions determine how the current flow behaves in respect of SACK 1168 * handling. SACK is negotiated with the peer, and therefore it can vary 1169 * between different flows. 1170 * 1171 * tcp_is_sack - SACK enabled 1172 * tcp_is_reno - No SACK 1173 */ 1174 static inline int tcp_is_sack(const struct tcp_sock *tp) 1175 { 1176 return likely(tp->rx_opt.sack_ok); 1177 } 1178 1179 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1180 { 1181 return !tcp_is_sack(tp); 1182 } 1183 1184 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1185 { 1186 return tp->sacked_out + tp->lost_out; 1187 } 1188 1189 /* This determines how many packets are "in the network" to the best 1190 * of our knowledge. In many cases it is conservative, but where 1191 * detailed information is available from the receiver (via SACK 1192 * blocks etc.) we can make more aggressive calculations. 1193 * 1194 * Use this for decisions involving congestion control, use just 1195 * tp->packets_out to determine if the send queue is empty or not. 1196 * 1197 * Read this equation as: 1198 * 1199 * "Packets sent once on transmission queue" MINUS 1200 * "Packets left network, but not honestly ACKed yet" PLUS 1201 * "Packets fast retransmitted" 1202 */ 1203 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1204 { 1205 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1206 } 1207 1208 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1209 1210 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1211 { 1212 return tp->snd_cwnd < tp->snd_ssthresh; 1213 } 1214 1215 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1216 { 1217 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1218 } 1219 1220 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1221 { 1222 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1223 (1 << inet_csk(sk)->icsk_ca_state); 1224 } 1225 1226 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1227 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1228 * ssthresh. 1229 */ 1230 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1231 { 1232 const struct tcp_sock *tp = tcp_sk(sk); 1233 1234 if (tcp_in_cwnd_reduction(sk)) 1235 return tp->snd_ssthresh; 1236 else 1237 return max(tp->snd_ssthresh, 1238 ((tp->snd_cwnd >> 1) + 1239 (tp->snd_cwnd >> 2))); 1240 } 1241 1242 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1243 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1244 1245 void tcp_enter_cwr(struct sock *sk); 1246 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1247 1248 /* The maximum number of MSS of available cwnd for which TSO defers 1249 * sending if not using sysctl_tcp_tso_win_divisor. 1250 */ 1251 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1252 { 1253 return 3; 1254 } 1255 1256 /* Returns end sequence number of the receiver's advertised window */ 1257 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1258 { 1259 return tp->snd_una + tp->snd_wnd; 1260 } 1261 1262 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1263 * flexible approach. The RFC suggests cwnd should not be raised unless 1264 * it was fully used previously. And that's exactly what we do in 1265 * congestion avoidance mode. But in slow start we allow cwnd to grow 1266 * as long as the application has used half the cwnd. 1267 * Example : 1268 * cwnd is 10 (IW10), but application sends 9 frames. 1269 * We allow cwnd to reach 18 when all frames are ACKed. 1270 * This check is safe because it's as aggressive as slow start which already 1271 * risks 100% overshoot. The advantage is that we discourage application to 1272 * either send more filler packets or data to artificially blow up the cwnd 1273 * usage, and allow application-limited process to probe bw more aggressively. 1274 */ 1275 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1276 { 1277 const struct tcp_sock *tp = tcp_sk(sk); 1278 1279 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1280 if (tcp_in_slow_start(tp)) 1281 return tp->snd_cwnd < 2 * tp->max_packets_out; 1282 1283 return tp->is_cwnd_limited; 1284 } 1285 1286 /* BBR congestion control needs pacing. 1287 * Same remark for SO_MAX_PACING_RATE. 1288 * sch_fq packet scheduler is efficiently handling pacing, 1289 * but is not always installed/used. 1290 * Return true if TCP stack should pace packets itself. 1291 */ 1292 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1293 { 1294 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1295 } 1296 1297 /* Estimates in how many jiffies next packet for this flow can be sent. 1298 * Scheduling a retransmit timer too early would be silly. 1299 */ 1300 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1301 { 1302 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1303 1304 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1305 } 1306 1307 static inline void tcp_reset_xmit_timer(struct sock *sk, 1308 const int what, 1309 unsigned long when, 1310 const unsigned long max_when) 1311 { 1312 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk), 1313 max_when); 1314 } 1315 1316 /* Something is really bad, we could not queue an additional packet, 1317 * because qdisc is full or receiver sent a 0 window, or we are paced. 1318 * We do not want to add fuel to the fire, or abort too early, 1319 * so make sure the timer we arm now is at least 200ms in the future, 1320 * regardless of current icsk_rto value (as it could be ~2ms) 1321 */ 1322 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1323 { 1324 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1325 } 1326 1327 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1328 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1329 unsigned long max_when) 1330 { 1331 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1332 inet_csk(sk)->icsk_backoff); 1333 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1334 1335 return (unsigned long)min_t(u64, when, max_when); 1336 } 1337 1338 static inline void tcp_check_probe_timer(struct sock *sk) 1339 { 1340 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1341 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1342 tcp_probe0_base(sk), TCP_RTO_MAX); 1343 } 1344 1345 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1346 { 1347 tp->snd_wl1 = seq; 1348 } 1349 1350 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1351 { 1352 tp->snd_wl1 = seq; 1353 } 1354 1355 /* 1356 * Calculate(/check) TCP checksum 1357 */ 1358 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1359 __be32 daddr, __wsum base) 1360 { 1361 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1362 } 1363 1364 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1365 { 1366 return !skb_csum_unnecessary(skb) && 1367 __skb_checksum_complete(skb); 1368 } 1369 1370 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); 1371 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1372 void tcp_set_state(struct sock *sk, int state); 1373 void tcp_done(struct sock *sk); 1374 int tcp_abort(struct sock *sk, int err); 1375 1376 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1377 { 1378 rx_opt->dsack = 0; 1379 rx_opt->num_sacks = 0; 1380 } 1381 1382 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1383 1384 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1385 { 1386 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1387 struct tcp_sock *tp = tcp_sk(sk); 1388 s32 delta; 1389 1390 if (!sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle || tp->packets_out || 1391 ca_ops->cong_control) 1392 return; 1393 delta = tcp_jiffies32 - tp->lsndtime; 1394 if (delta > inet_csk(sk)->icsk_rto) 1395 tcp_cwnd_restart(sk, delta); 1396 } 1397 1398 /* Determine a window scaling and initial window to offer. */ 1399 void tcp_select_initial_window(const struct sock *sk, int __space, 1400 __u32 mss, __u32 *rcv_wnd, 1401 __u32 *window_clamp, int wscale_ok, 1402 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1403 1404 static inline int tcp_win_from_space(const struct sock *sk, int space) 1405 { 1406 int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; 1407 1408 return tcp_adv_win_scale <= 0 ? 1409 (space>>(-tcp_adv_win_scale)) : 1410 space - (space>>tcp_adv_win_scale); 1411 } 1412 1413 /* Note: caller must be prepared to deal with negative returns */ 1414 static inline int tcp_space(const struct sock *sk) 1415 { 1416 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1417 READ_ONCE(sk->sk_backlog.len) - 1418 atomic_read(&sk->sk_rmem_alloc)); 1419 } 1420 1421 static inline int tcp_full_space(const struct sock *sk) 1422 { 1423 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1424 } 1425 1426 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1427 1428 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1429 * If 87.5 % (7/8) of the space has been consumed, we want to override 1430 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1431 * len/truesize ratio. 1432 */ 1433 static inline bool tcp_rmem_pressure(const struct sock *sk) 1434 { 1435 int rcvbuf, threshold; 1436 1437 if (tcp_under_memory_pressure(sk)) 1438 return true; 1439 1440 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1441 threshold = rcvbuf - (rcvbuf >> 3); 1442 1443 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1444 } 1445 1446 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1447 { 1448 const struct tcp_sock *tp = tcp_sk(sk); 1449 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1450 1451 if (avail <= 0) 1452 return false; 1453 1454 return (avail >= target) || tcp_rmem_pressure(sk) || 1455 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1456 } 1457 1458 extern void tcp_openreq_init_rwin(struct request_sock *req, 1459 const struct sock *sk_listener, 1460 const struct dst_entry *dst); 1461 1462 void tcp_enter_memory_pressure(struct sock *sk); 1463 void tcp_leave_memory_pressure(struct sock *sk); 1464 1465 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1466 { 1467 struct net *net = sock_net((struct sock *)tp); 1468 1469 return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl; 1470 } 1471 1472 static inline int keepalive_time_when(const struct tcp_sock *tp) 1473 { 1474 struct net *net = sock_net((struct sock *)tp); 1475 1476 return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time; 1477 } 1478 1479 static inline int keepalive_probes(const struct tcp_sock *tp) 1480 { 1481 struct net *net = sock_net((struct sock *)tp); 1482 1483 return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes; 1484 } 1485 1486 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1487 { 1488 const struct inet_connection_sock *icsk = &tp->inet_conn; 1489 1490 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1491 tcp_jiffies32 - tp->rcv_tstamp); 1492 } 1493 1494 static inline int tcp_fin_time(const struct sock *sk) 1495 { 1496 int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout; 1497 const int rto = inet_csk(sk)->icsk_rto; 1498 1499 if (fin_timeout < (rto << 2) - (rto >> 1)) 1500 fin_timeout = (rto << 2) - (rto >> 1); 1501 1502 return fin_timeout; 1503 } 1504 1505 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1506 int paws_win) 1507 { 1508 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1509 return true; 1510 if (unlikely(!time_before32(ktime_get_seconds(), 1511 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1512 return true; 1513 /* 1514 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1515 * then following tcp messages have valid values. Ignore 0 value, 1516 * or else 'negative' tsval might forbid us to accept their packets. 1517 */ 1518 if (!rx_opt->ts_recent) 1519 return true; 1520 return false; 1521 } 1522 1523 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1524 int rst) 1525 { 1526 if (tcp_paws_check(rx_opt, 0)) 1527 return false; 1528 1529 /* RST segments are not recommended to carry timestamp, 1530 and, if they do, it is recommended to ignore PAWS because 1531 "their cleanup function should take precedence over timestamps." 1532 Certainly, it is mistake. It is necessary to understand the reasons 1533 of this constraint to relax it: if peer reboots, clock may go 1534 out-of-sync and half-open connections will not be reset. 1535 Actually, the problem would be not existing if all 1536 the implementations followed draft about maintaining clock 1537 via reboots. Linux-2.2 DOES NOT! 1538 1539 However, we can relax time bounds for RST segments to MSL. 1540 */ 1541 if (rst && !time_before32(ktime_get_seconds(), 1542 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1543 return false; 1544 return true; 1545 } 1546 1547 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1548 int mib_idx, u32 *last_oow_ack_time); 1549 1550 static inline void tcp_mib_init(struct net *net) 1551 { 1552 /* See RFC 2012 */ 1553 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1554 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1555 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1556 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1557 } 1558 1559 /* from STCP */ 1560 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1561 { 1562 tp->lost_skb_hint = NULL; 1563 } 1564 1565 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1566 { 1567 tcp_clear_retrans_hints_partial(tp); 1568 tp->retransmit_skb_hint = NULL; 1569 } 1570 1571 union tcp_md5_addr { 1572 struct in_addr a4; 1573 #if IS_ENABLED(CONFIG_IPV6) 1574 struct in6_addr a6; 1575 #endif 1576 }; 1577 1578 /* - key database */ 1579 struct tcp_md5sig_key { 1580 struct hlist_node node; 1581 u8 keylen; 1582 u8 family; /* AF_INET or AF_INET6 */ 1583 u8 prefixlen; 1584 union tcp_md5_addr addr; 1585 int l3index; /* set if key added with L3 scope */ 1586 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1587 struct rcu_head rcu; 1588 }; 1589 1590 /* - sock block */ 1591 struct tcp_md5sig_info { 1592 struct hlist_head head; 1593 struct rcu_head rcu; 1594 }; 1595 1596 /* - pseudo header */ 1597 struct tcp4_pseudohdr { 1598 __be32 saddr; 1599 __be32 daddr; 1600 __u8 pad; 1601 __u8 protocol; 1602 __be16 len; 1603 }; 1604 1605 struct tcp6_pseudohdr { 1606 struct in6_addr saddr; 1607 struct in6_addr daddr; 1608 __be32 len; 1609 __be32 protocol; /* including padding */ 1610 }; 1611 1612 union tcp_md5sum_block { 1613 struct tcp4_pseudohdr ip4; 1614 #if IS_ENABLED(CONFIG_IPV6) 1615 struct tcp6_pseudohdr ip6; 1616 #endif 1617 }; 1618 1619 /* - pool: digest algorithm, hash description and scratch buffer */ 1620 struct tcp_md5sig_pool { 1621 struct ahash_request *md5_req; 1622 void *scratch; 1623 }; 1624 1625 /* - functions */ 1626 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1627 const struct sock *sk, const struct sk_buff *skb); 1628 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1629 int family, u8 prefixlen, int l3index, 1630 const u8 *newkey, u8 newkeylen, gfp_t gfp); 1631 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1632 int family, u8 prefixlen, int l3index); 1633 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1634 const struct sock *addr_sk); 1635 1636 #ifdef CONFIG_TCP_MD5SIG 1637 #include <linux/jump_label.h> 1638 extern struct static_key_false tcp_md5_needed; 1639 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1640 const union tcp_md5_addr *addr, 1641 int family); 1642 static inline struct tcp_md5sig_key * 1643 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1644 const union tcp_md5_addr *addr, int family) 1645 { 1646 if (!static_branch_unlikely(&tcp_md5_needed)) 1647 return NULL; 1648 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1649 } 1650 1651 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1652 #else 1653 static inline struct tcp_md5sig_key * 1654 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1655 const union tcp_md5_addr *addr, int family) 1656 { 1657 return NULL; 1658 } 1659 #define tcp_twsk_md5_key(twsk) NULL 1660 #endif 1661 1662 bool tcp_alloc_md5sig_pool(void); 1663 1664 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1665 static inline void tcp_put_md5sig_pool(void) 1666 { 1667 local_bh_enable(); 1668 } 1669 1670 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1671 unsigned int header_len); 1672 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1673 const struct tcp_md5sig_key *key); 1674 1675 /* From tcp_fastopen.c */ 1676 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1677 struct tcp_fastopen_cookie *cookie); 1678 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1679 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1680 u16 try_exp); 1681 struct tcp_fastopen_request { 1682 /* Fast Open cookie. Size 0 means a cookie request */ 1683 struct tcp_fastopen_cookie cookie; 1684 struct msghdr *data; /* data in MSG_FASTOPEN */ 1685 size_t size; 1686 int copied; /* queued in tcp_connect() */ 1687 struct ubuf_info *uarg; 1688 }; 1689 void tcp_free_fastopen_req(struct tcp_sock *tp); 1690 void tcp_fastopen_destroy_cipher(struct sock *sk); 1691 void tcp_fastopen_ctx_destroy(struct net *net); 1692 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1693 void *primary_key, void *backup_key); 1694 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1695 u64 *key); 1696 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1697 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1698 struct request_sock *req, 1699 struct tcp_fastopen_cookie *foc, 1700 const struct dst_entry *dst); 1701 void tcp_fastopen_init_key_once(struct net *net); 1702 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1703 struct tcp_fastopen_cookie *cookie); 1704 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1705 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1706 #define TCP_FASTOPEN_KEY_MAX 2 1707 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1708 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1709 1710 /* Fastopen key context */ 1711 struct tcp_fastopen_context { 1712 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1713 int num; 1714 struct rcu_head rcu; 1715 }; 1716 1717 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout; 1718 void tcp_fastopen_active_disable(struct sock *sk); 1719 bool tcp_fastopen_active_should_disable(struct sock *sk); 1720 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1721 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1722 1723 /* Caller needs to wrap with rcu_read_(un)lock() */ 1724 static inline 1725 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1726 { 1727 struct tcp_fastopen_context *ctx; 1728 1729 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1730 if (!ctx) 1731 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1732 return ctx; 1733 } 1734 1735 static inline 1736 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1737 const struct tcp_fastopen_cookie *orig) 1738 { 1739 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1740 orig->len == foc->len && 1741 !memcmp(orig->val, foc->val, foc->len)) 1742 return true; 1743 return false; 1744 } 1745 1746 static inline 1747 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1748 { 1749 return ctx->num; 1750 } 1751 1752 /* Latencies incurred by various limits for a sender. They are 1753 * chronograph-like stats that are mutually exclusive. 1754 */ 1755 enum tcp_chrono { 1756 TCP_CHRONO_UNSPEC, 1757 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1758 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1759 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1760 __TCP_CHRONO_MAX, 1761 }; 1762 1763 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1764 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1765 1766 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1767 * the same memory storage than skb->destructor/_skb_refdst 1768 */ 1769 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1770 { 1771 skb->destructor = NULL; 1772 skb->_skb_refdst = 0UL; 1773 } 1774 1775 #define tcp_skb_tsorted_save(skb) { \ 1776 unsigned long _save = skb->_skb_refdst; \ 1777 skb->_skb_refdst = 0UL; 1778 1779 #define tcp_skb_tsorted_restore(skb) \ 1780 skb->_skb_refdst = _save; \ 1781 } 1782 1783 void tcp_write_queue_purge(struct sock *sk); 1784 1785 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1786 { 1787 return skb_rb_first(&sk->tcp_rtx_queue); 1788 } 1789 1790 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1791 { 1792 return skb_rb_last(&sk->tcp_rtx_queue); 1793 } 1794 1795 static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) 1796 { 1797 return skb_peek(&sk->sk_write_queue); 1798 } 1799 1800 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1801 { 1802 return skb_peek_tail(&sk->sk_write_queue); 1803 } 1804 1805 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1806 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1807 1808 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1809 { 1810 return skb_peek(&sk->sk_write_queue); 1811 } 1812 1813 static inline bool tcp_skb_is_last(const struct sock *sk, 1814 const struct sk_buff *skb) 1815 { 1816 return skb_queue_is_last(&sk->sk_write_queue, skb); 1817 } 1818 1819 /** 1820 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1821 * @sk: socket 1822 * 1823 * Since the write queue can have a temporary empty skb in it, 1824 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1825 */ 1826 static inline bool tcp_write_queue_empty(const struct sock *sk) 1827 { 1828 const struct tcp_sock *tp = tcp_sk(sk); 1829 1830 return tp->write_seq == tp->snd_nxt; 1831 } 1832 1833 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1834 { 1835 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1836 } 1837 1838 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1839 { 1840 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1841 } 1842 1843 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1844 { 1845 __skb_queue_tail(&sk->sk_write_queue, skb); 1846 1847 /* Queue it, remembering where we must start sending. */ 1848 if (sk->sk_write_queue.next == skb) 1849 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1850 } 1851 1852 /* Insert new before skb on the write queue of sk. */ 1853 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1854 struct sk_buff *skb, 1855 struct sock *sk) 1856 { 1857 __skb_queue_before(&sk->sk_write_queue, skb, new); 1858 } 1859 1860 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1861 { 1862 tcp_skb_tsorted_anchor_cleanup(skb); 1863 __skb_unlink(skb, &sk->sk_write_queue); 1864 } 1865 1866 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1867 1868 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1869 { 1870 tcp_skb_tsorted_anchor_cleanup(skb); 1871 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1872 } 1873 1874 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1875 { 1876 list_del(&skb->tcp_tsorted_anchor); 1877 tcp_rtx_queue_unlink(skb, sk); 1878 sk_wmem_free_skb(sk, skb); 1879 } 1880 1881 static inline void tcp_push_pending_frames(struct sock *sk) 1882 { 1883 if (tcp_send_head(sk)) { 1884 struct tcp_sock *tp = tcp_sk(sk); 1885 1886 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1887 } 1888 } 1889 1890 /* Start sequence of the skb just after the highest skb with SACKed 1891 * bit, valid only if sacked_out > 0 or when the caller has ensured 1892 * validity by itself. 1893 */ 1894 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1895 { 1896 if (!tp->sacked_out) 1897 return tp->snd_una; 1898 1899 if (tp->highest_sack == NULL) 1900 return tp->snd_nxt; 1901 1902 return TCP_SKB_CB(tp->highest_sack)->seq; 1903 } 1904 1905 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1906 { 1907 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 1908 } 1909 1910 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1911 { 1912 return tcp_sk(sk)->highest_sack; 1913 } 1914 1915 static inline void tcp_highest_sack_reset(struct sock *sk) 1916 { 1917 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 1918 } 1919 1920 /* Called when old skb is about to be deleted and replaced by new skb */ 1921 static inline void tcp_highest_sack_replace(struct sock *sk, 1922 struct sk_buff *old, 1923 struct sk_buff *new) 1924 { 1925 if (old == tcp_highest_sack(sk)) 1926 tcp_sk(sk)->highest_sack = new; 1927 } 1928 1929 /* This helper checks if socket has IP_TRANSPARENT set */ 1930 static inline bool inet_sk_transparent(const struct sock *sk) 1931 { 1932 switch (sk->sk_state) { 1933 case TCP_TIME_WAIT: 1934 return inet_twsk(sk)->tw_transparent; 1935 case TCP_NEW_SYN_RECV: 1936 return inet_rsk(inet_reqsk(sk))->no_srccheck; 1937 } 1938 return inet_sk(sk)->transparent; 1939 } 1940 1941 /* Determines whether this is a thin stream (which may suffer from 1942 * increased latency). Used to trigger latency-reducing mechanisms. 1943 */ 1944 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 1945 { 1946 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 1947 } 1948 1949 /* /proc */ 1950 enum tcp_seq_states { 1951 TCP_SEQ_STATE_LISTENING, 1952 TCP_SEQ_STATE_ESTABLISHED, 1953 }; 1954 1955 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 1956 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 1957 void tcp_seq_stop(struct seq_file *seq, void *v); 1958 1959 struct tcp_seq_afinfo { 1960 sa_family_t family; 1961 }; 1962 1963 struct tcp_iter_state { 1964 struct seq_net_private p; 1965 enum tcp_seq_states state; 1966 struct sock *syn_wait_sk; 1967 struct tcp_seq_afinfo *bpf_seq_afinfo; 1968 int bucket, offset, sbucket, num; 1969 loff_t last_pos; 1970 }; 1971 1972 extern struct request_sock_ops tcp_request_sock_ops; 1973 extern struct request_sock_ops tcp6_request_sock_ops; 1974 1975 void tcp_v4_destroy_sock(struct sock *sk); 1976 1977 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 1978 netdev_features_t features); 1979 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 1980 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 1981 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 1982 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 1983 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 1984 int tcp_gro_complete(struct sk_buff *skb); 1985 1986 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 1987 1988 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 1989 { 1990 struct net *net = sock_net((struct sock *)tp); 1991 return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat; 1992 } 1993 1994 bool tcp_stream_memory_free(const struct sock *sk, int wake); 1995 1996 #ifdef CONFIG_PROC_FS 1997 int tcp4_proc_init(void); 1998 void tcp4_proc_exit(void); 1999 #endif 2000 2001 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2002 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2003 const struct tcp_request_sock_ops *af_ops, 2004 struct sock *sk, struct sk_buff *skb); 2005 2006 /* TCP af-specific functions */ 2007 struct tcp_sock_af_ops { 2008 #ifdef CONFIG_TCP_MD5SIG 2009 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2010 const struct sock *addr_sk); 2011 int (*calc_md5_hash)(char *location, 2012 const struct tcp_md5sig_key *md5, 2013 const struct sock *sk, 2014 const struct sk_buff *skb); 2015 int (*md5_parse)(struct sock *sk, 2016 int optname, 2017 sockptr_t optval, 2018 int optlen); 2019 #endif 2020 }; 2021 2022 struct tcp_request_sock_ops { 2023 u16 mss_clamp; 2024 #ifdef CONFIG_TCP_MD5SIG 2025 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2026 const struct sock *addr_sk); 2027 int (*calc_md5_hash) (char *location, 2028 const struct tcp_md5sig_key *md5, 2029 const struct sock *sk, 2030 const struct sk_buff *skb); 2031 #endif 2032 #ifdef CONFIG_SYN_COOKIES 2033 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2034 __u16 *mss); 2035 #endif 2036 struct dst_entry *(*route_req)(const struct sock *sk, 2037 struct sk_buff *skb, 2038 struct flowi *fl, 2039 struct request_sock *req); 2040 u32 (*init_seq)(const struct sk_buff *skb); 2041 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2042 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2043 struct flowi *fl, struct request_sock *req, 2044 struct tcp_fastopen_cookie *foc, 2045 enum tcp_synack_type synack_type, 2046 struct sk_buff *syn_skb); 2047 }; 2048 2049 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2050 #if IS_ENABLED(CONFIG_IPV6) 2051 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2052 #endif 2053 2054 #ifdef CONFIG_SYN_COOKIES 2055 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2056 const struct sock *sk, struct sk_buff *skb, 2057 __u16 *mss) 2058 { 2059 tcp_synq_overflow(sk); 2060 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2061 return ops->cookie_init_seq(skb, mss); 2062 } 2063 #else 2064 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2065 const struct sock *sk, struct sk_buff *skb, 2066 __u16 *mss) 2067 { 2068 return 0; 2069 } 2070 #endif 2071 2072 int tcpv4_offload_init(void); 2073 2074 void tcp_v4_init(void); 2075 void tcp_init(void); 2076 2077 /* tcp_recovery.c */ 2078 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2079 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2080 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2081 u32 reo_wnd); 2082 extern bool tcp_rack_mark_lost(struct sock *sk); 2083 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2084 u64 xmit_time); 2085 extern void tcp_rack_reo_timeout(struct sock *sk); 2086 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2087 2088 /* At how many usecs into the future should the RTO fire? */ 2089 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2090 { 2091 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2092 u32 rto = inet_csk(sk)->icsk_rto; 2093 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2094 2095 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2096 } 2097 2098 /* 2099 * Save and compile IPv4 options, return a pointer to it 2100 */ 2101 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2102 struct sk_buff *skb) 2103 { 2104 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2105 struct ip_options_rcu *dopt = NULL; 2106 2107 if (opt->optlen) { 2108 int opt_size = sizeof(*dopt) + opt->optlen; 2109 2110 dopt = kmalloc(opt_size, GFP_ATOMIC); 2111 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2112 kfree(dopt); 2113 dopt = NULL; 2114 } 2115 } 2116 return dopt; 2117 } 2118 2119 /* locally generated TCP pure ACKs have skb->truesize == 2 2120 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2121 * This is much faster than dissecting the packet to find out. 2122 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2123 */ 2124 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2125 { 2126 return skb->truesize == 2; 2127 } 2128 2129 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2130 { 2131 skb->truesize = 2; 2132 } 2133 2134 static inline int tcp_inq(struct sock *sk) 2135 { 2136 struct tcp_sock *tp = tcp_sk(sk); 2137 int answ; 2138 2139 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2140 answ = 0; 2141 } else if (sock_flag(sk, SOCK_URGINLINE) || 2142 !tp->urg_data || 2143 before(tp->urg_seq, tp->copied_seq) || 2144 !before(tp->urg_seq, tp->rcv_nxt)) { 2145 2146 answ = tp->rcv_nxt - tp->copied_seq; 2147 2148 /* Subtract 1, if FIN was received */ 2149 if (answ && sock_flag(sk, SOCK_DONE)) 2150 answ--; 2151 } else { 2152 answ = tp->urg_seq - tp->copied_seq; 2153 } 2154 2155 return answ; 2156 } 2157 2158 int tcp_peek_len(struct socket *sock); 2159 2160 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2161 { 2162 u16 segs_in; 2163 2164 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2165 tp->segs_in += segs_in; 2166 if (skb->len > tcp_hdrlen(skb)) 2167 tp->data_segs_in += segs_in; 2168 } 2169 2170 /* 2171 * TCP listen path runs lockless. 2172 * We forced "struct sock" to be const qualified to make sure 2173 * we don't modify one of its field by mistake. 2174 * Here, we increment sk_drops which is an atomic_t, so we can safely 2175 * make sock writable again. 2176 */ 2177 static inline void tcp_listendrop(const struct sock *sk) 2178 { 2179 atomic_inc(&((struct sock *)sk)->sk_drops); 2180 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2181 } 2182 2183 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2184 2185 /* 2186 * Interface for adding Upper Level Protocols over TCP 2187 */ 2188 2189 #define TCP_ULP_NAME_MAX 16 2190 #define TCP_ULP_MAX 128 2191 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2192 2193 struct tcp_ulp_ops { 2194 struct list_head list; 2195 2196 /* initialize ulp */ 2197 int (*init)(struct sock *sk); 2198 /* update ulp */ 2199 void (*update)(struct sock *sk, struct proto *p, 2200 void (*write_space)(struct sock *sk)); 2201 /* cleanup ulp */ 2202 void (*release)(struct sock *sk); 2203 /* diagnostic */ 2204 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2205 size_t (*get_info_size)(const struct sock *sk); 2206 /* clone ulp */ 2207 void (*clone)(const struct request_sock *req, struct sock *newsk, 2208 const gfp_t priority); 2209 2210 char name[TCP_ULP_NAME_MAX]; 2211 struct module *owner; 2212 }; 2213 int tcp_register_ulp(struct tcp_ulp_ops *type); 2214 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2215 int tcp_set_ulp(struct sock *sk, const char *name); 2216 void tcp_get_available_ulp(char *buf, size_t len); 2217 void tcp_cleanup_ulp(struct sock *sk); 2218 void tcp_update_ulp(struct sock *sk, struct proto *p, 2219 void (*write_space)(struct sock *sk)); 2220 2221 #define MODULE_ALIAS_TCP_ULP(name) \ 2222 __MODULE_INFO(alias, alias_userspace, name); \ 2223 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2224 2225 struct sk_msg; 2226 struct sk_psock; 2227 2228 #ifdef CONFIG_BPF_STREAM_PARSER 2229 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 2230 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2231 #else 2232 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2233 { 2234 } 2235 #endif /* CONFIG_BPF_STREAM_PARSER */ 2236 2237 #ifdef CONFIG_NET_SOCK_MSG 2238 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes, 2239 int flags); 2240 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, 2241 struct msghdr *msg, int len, int flags); 2242 #endif /* CONFIG_NET_SOCK_MSG */ 2243 2244 #ifdef CONFIG_CGROUP_BPF 2245 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2246 struct sk_buff *skb, 2247 unsigned int end_offset) 2248 { 2249 skops->skb = skb; 2250 skops->skb_data_end = skb->data + end_offset; 2251 } 2252 #else 2253 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2254 struct sk_buff *skb, 2255 unsigned int end_offset) 2256 { 2257 } 2258 #endif 2259 2260 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2261 * is < 0, then the BPF op failed (for example if the loaded BPF 2262 * program does not support the chosen operation or there is no BPF 2263 * program loaded). 2264 */ 2265 #ifdef CONFIG_BPF 2266 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2267 { 2268 struct bpf_sock_ops_kern sock_ops; 2269 int ret; 2270 2271 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2272 if (sk_fullsock(sk)) { 2273 sock_ops.is_fullsock = 1; 2274 sock_owned_by_me(sk); 2275 } 2276 2277 sock_ops.sk = sk; 2278 sock_ops.op = op; 2279 if (nargs > 0) 2280 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2281 2282 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2283 if (ret == 0) 2284 ret = sock_ops.reply; 2285 else 2286 ret = -1; 2287 return ret; 2288 } 2289 2290 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2291 { 2292 u32 args[2] = {arg1, arg2}; 2293 2294 return tcp_call_bpf(sk, op, 2, args); 2295 } 2296 2297 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2298 u32 arg3) 2299 { 2300 u32 args[3] = {arg1, arg2, arg3}; 2301 2302 return tcp_call_bpf(sk, op, 3, args); 2303 } 2304 2305 #else 2306 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2307 { 2308 return -EPERM; 2309 } 2310 2311 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2312 { 2313 return -EPERM; 2314 } 2315 2316 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2317 u32 arg3) 2318 { 2319 return -EPERM; 2320 } 2321 2322 #endif 2323 2324 static inline u32 tcp_timeout_init(struct sock *sk) 2325 { 2326 int timeout; 2327 2328 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2329 2330 if (timeout <= 0) 2331 timeout = TCP_TIMEOUT_INIT; 2332 return timeout; 2333 } 2334 2335 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2336 { 2337 int rwnd; 2338 2339 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2340 2341 if (rwnd < 0) 2342 rwnd = 0; 2343 return rwnd; 2344 } 2345 2346 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2347 { 2348 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2349 } 2350 2351 static inline void tcp_bpf_rtt(struct sock *sk) 2352 { 2353 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2354 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2355 } 2356 2357 #if IS_ENABLED(CONFIG_SMC) 2358 extern struct static_key_false tcp_have_smc; 2359 #endif 2360 2361 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2362 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2363 void (*cad)(struct sock *sk, u32 ack_seq)); 2364 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2365 void clean_acked_data_flush(void); 2366 #endif 2367 2368 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2369 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2370 const struct tcp_sock *tp) 2371 { 2372 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2373 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2374 } 2375 2376 /* Compute Earliest Departure Time for some control packets 2377 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2378 */ 2379 static inline u64 tcp_transmit_time(const struct sock *sk) 2380 { 2381 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2382 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2383 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2384 2385 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2386 } 2387 return 0; 2388 } 2389 2390 #endif /* _TCP_H */ 2391