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 DECLARE_PER_CPU(unsigned int, tcp_orphan_count); 52 int tcp_orphan_count_sum(void); 53 54 void tcp_time_wait(struct sock *sk, int state, int timeo); 55 56 #define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER) 57 #define MAX_TCP_OPTION_SPACE 40 58 #define TCP_MIN_SND_MSS 48 59 #define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) 60 61 /* 62 * Never offer a window over 32767 without using window scaling. Some 63 * poor stacks do signed 16bit maths! 64 */ 65 #define MAX_TCP_WINDOW 32767U 66 67 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 68 #define TCP_MIN_MSS 88U 69 70 /* The initial MTU to use for probing */ 71 #define TCP_BASE_MSS 1024 72 73 /* probing interval, default to 10 minutes as per RFC4821 */ 74 #define TCP_PROBE_INTERVAL 600 75 76 /* Specify interval when tcp mtu probing will stop */ 77 #define TCP_PROBE_THRESHOLD 8 78 79 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 80 #define TCP_FASTRETRANS_THRESH 3 81 82 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 83 #define TCP_MAX_QUICKACKS 16U 84 85 /* Maximal number of window scale according to RFC1323 */ 86 #define TCP_MAX_WSCALE 14U 87 88 /* urg_data states */ 89 #define TCP_URG_VALID 0x0100 90 #define TCP_URG_NOTYET 0x0200 91 #define TCP_URG_READ 0x0400 92 93 #define TCP_RETR1 3 /* 94 * This is how many retries it does before it 95 * tries to figure out if the gateway is 96 * down. Minimal RFC value is 3; it corresponds 97 * to ~3sec-8min depending on RTO. 98 */ 99 100 #define TCP_RETR2 15 /* 101 * This should take at least 102 * 90 minutes to time out. 103 * RFC1122 says that the limit is 100 sec. 104 * 15 is ~13-30min depending on RTO. 105 */ 106 107 #define TCP_SYN_RETRIES 6 /* This is how many retries are done 108 * when active opening a connection. 109 * RFC1122 says the minimum retry MUST 110 * be at least 180secs. Nevertheless 111 * this value is corresponding to 112 * 63secs of retransmission with the 113 * current initial RTO. 114 */ 115 116 #define TCP_SYNACK_RETRIES 5 /* This is how may retries are done 117 * when passive opening a connection. 118 * This is corresponding to 31secs of 119 * retransmission with the current 120 * initial RTO. 121 */ 122 123 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 124 * state, about 60 seconds */ 125 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 126 /* BSD style FIN_WAIT2 deadlock breaker. 127 * It used to be 3min, new value is 60sec, 128 * to combine FIN-WAIT-2 timeout with 129 * TIME-WAIT timer. 130 */ 131 #define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */ 132 133 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 134 #if HZ >= 100 135 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 136 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 137 #else 138 #define TCP_DELACK_MIN 4U 139 #define TCP_ATO_MIN 4U 140 #endif 141 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 142 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 143 #define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */ 144 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 145 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 146 * used as a fallback RTO for the 147 * initial data transmission if no 148 * valid RTT sample has been acquired, 149 * most likely due to retrans in 3WHS. 150 */ 151 152 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 153 * for local resources. 154 */ 155 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 156 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 157 #define TCP_KEEPALIVE_INTVL (75*HZ) 158 159 #define MAX_TCP_KEEPIDLE 32767 160 #define MAX_TCP_KEEPINTVL 32767 161 #define MAX_TCP_KEEPCNT 127 162 #define MAX_TCP_SYNCNT 127 163 164 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 165 166 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 167 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 168 * after this time. It should be equal 169 * (or greater than) TCP_TIMEWAIT_LEN 170 * to provide reliability equal to one 171 * provided by timewait state. 172 */ 173 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 174 * timestamps. It must be less than 175 * minimal timewait lifetime. 176 */ 177 /* 178 * TCP option 179 */ 180 181 #define TCPOPT_NOP 1 /* Padding */ 182 #define TCPOPT_EOL 0 /* End of options */ 183 #define TCPOPT_MSS 2 /* Segment size negotiating */ 184 #define TCPOPT_WINDOW 3 /* Window scaling */ 185 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 186 #define TCPOPT_SACK 5 /* SACK Block */ 187 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 188 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 189 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ 190 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 191 #define TCPOPT_EXP 254 /* Experimental */ 192 /* Magic number to be after the option value for sharing TCP 193 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 194 */ 195 #define TCPOPT_FASTOPEN_MAGIC 0xF989 196 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 197 198 /* 199 * TCP option lengths 200 */ 201 202 #define TCPOLEN_MSS 4 203 #define TCPOLEN_WINDOW 3 204 #define TCPOLEN_SACK_PERM 2 205 #define TCPOLEN_TIMESTAMP 10 206 #define TCPOLEN_MD5SIG 18 207 #define TCPOLEN_FASTOPEN_BASE 2 208 #define TCPOLEN_EXP_FASTOPEN_BASE 4 209 #define TCPOLEN_EXP_SMC_BASE 6 210 211 /* But this is what stacks really send out. */ 212 #define TCPOLEN_TSTAMP_ALIGNED 12 213 #define TCPOLEN_WSCALE_ALIGNED 4 214 #define TCPOLEN_SACKPERM_ALIGNED 4 215 #define TCPOLEN_SACK_BASE 2 216 #define TCPOLEN_SACK_BASE_ALIGNED 4 217 #define TCPOLEN_SACK_PERBLOCK 8 218 #define TCPOLEN_MD5SIG_ALIGNED 20 219 #define TCPOLEN_MSS_ALIGNED 4 220 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 221 222 /* Flags in tp->nonagle */ 223 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 224 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 225 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 226 227 /* TCP thin-stream limits */ 228 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 229 230 /* TCP initial congestion window as per rfc6928 */ 231 #define TCP_INIT_CWND 10 232 233 /* Bit Flags for sysctl_tcp_fastopen */ 234 #define TFO_CLIENT_ENABLE 1 235 #define TFO_SERVER_ENABLE 2 236 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 237 238 /* Accept SYN data w/o any cookie option */ 239 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 240 241 /* Force enable TFO on all listeners, i.e., not requiring the 242 * TCP_FASTOPEN socket option. 243 */ 244 #define TFO_SERVER_WO_SOCKOPT1 0x400 245 246 247 /* sysctl variables for tcp */ 248 extern int sysctl_tcp_max_orphans; 249 extern long sysctl_tcp_mem[3]; 250 251 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 252 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 253 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 254 255 extern atomic_long_t tcp_memory_allocated; 256 DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); 257 258 extern struct percpu_counter tcp_sockets_allocated; 259 extern unsigned long tcp_memory_pressure; 260 261 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 262 static inline bool tcp_under_memory_pressure(const struct sock *sk) 263 { 264 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 265 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 266 return true; 267 268 return READ_ONCE(tcp_memory_pressure); 269 } 270 /* 271 * The next routines deal with comparing 32 bit unsigned ints 272 * and worry about wraparound (automatic with unsigned arithmetic). 273 */ 274 275 static inline bool before(__u32 seq1, __u32 seq2) 276 { 277 return (__s32)(seq1-seq2) < 0; 278 } 279 #define after(seq2, seq1) before(seq1, seq2) 280 281 /* is s2<=s1<=s3 ? */ 282 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 283 { 284 return seq3 - seq2 >= seq1 - seq2; 285 } 286 287 static inline bool tcp_out_of_memory(struct sock *sk) 288 { 289 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 290 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 291 return true; 292 return false; 293 } 294 295 static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb) 296 { 297 sk_wmem_queued_add(sk, -skb->truesize); 298 if (!skb_zcopy_pure(skb)) 299 sk_mem_uncharge(sk, skb->truesize); 300 else 301 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb))); 302 __kfree_skb(skb); 303 } 304 305 void sk_forced_mem_schedule(struct sock *sk, int size); 306 307 bool tcp_check_oom(struct sock *sk, int shift); 308 309 310 extern struct proto tcp_prot; 311 312 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 313 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 314 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 315 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 316 317 void tcp_tasklet_init(void); 318 319 int tcp_v4_err(struct sk_buff *skb, u32); 320 321 void tcp_shutdown(struct sock *sk, int how); 322 323 int tcp_v4_early_demux(struct sk_buff *skb); 324 int tcp_v4_rcv(struct sk_buff *skb); 325 326 void tcp_remove_empty_skb(struct sock *sk); 327 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 328 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 329 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 330 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, 331 int flags); 332 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, 333 size_t size, int flags); 334 ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 335 size_t size, int flags); 336 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 337 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 338 int size_goal); 339 void tcp_release_cb(struct sock *sk); 340 void tcp_wfree(struct sk_buff *skb); 341 void tcp_write_timer_handler(struct sock *sk); 342 void tcp_delack_timer_handler(struct sock *sk); 343 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); 344 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 345 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 346 void tcp_rcv_space_adjust(struct sock *sk); 347 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 348 void tcp_twsk_destructor(struct sock *sk); 349 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 350 struct pipe_inode_info *pipe, size_t len, 351 unsigned int flags); 352 struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp, 353 bool force_schedule); 354 355 void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks); 356 static inline void tcp_dec_quickack_mode(struct sock *sk, 357 const unsigned int pkts) 358 { 359 struct inet_connection_sock *icsk = inet_csk(sk); 360 361 if (icsk->icsk_ack.quick) { 362 if (pkts >= icsk->icsk_ack.quick) { 363 icsk->icsk_ack.quick = 0; 364 /* Leaving quickack mode we deflate ATO. */ 365 icsk->icsk_ack.ato = TCP_ATO_MIN; 366 } else 367 icsk->icsk_ack.quick -= pkts; 368 } 369 } 370 371 #define TCP_ECN_OK 1 372 #define TCP_ECN_QUEUE_CWR 2 373 #define TCP_ECN_DEMAND_CWR 4 374 #define TCP_ECN_SEEN 8 375 376 enum tcp_tw_status { 377 TCP_TW_SUCCESS = 0, 378 TCP_TW_RST = 1, 379 TCP_TW_ACK = 2, 380 TCP_TW_SYN = 3 381 }; 382 383 384 enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 385 struct sk_buff *skb, 386 const struct tcphdr *th); 387 struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, 388 struct request_sock *req, bool fastopen, 389 bool *lost_race); 390 int tcp_child_process(struct sock *parent, struct sock *child, 391 struct sk_buff *skb); 392 void tcp_enter_loss(struct sock *sk); 393 void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag); 394 void tcp_clear_retrans(struct tcp_sock *tp); 395 void tcp_update_metrics(struct sock *sk); 396 void tcp_init_metrics(struct sock *sk); 397 void tcp_metrics_init(void); 398 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); 399 void __tcp_close(struct sock *sk, long timeout); 400 void tcp_close(struct sock *sk, long timeout); 401 void tcp_init_sock(struct sock *sk); 402 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb); 403 __poll_t tcp_poll(struct file *file, struct socket *sock, 404 struct poll_table_struct *wait); 405 int tcp_getsockopt(struct sock *sk, int level, int optname, 406 char __user *optval, int __user *optlen); 407 bool tcp_bpf_bypass_getsockopt(int level, int optname); 408 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 409 unsigned int optlen); 410 void tcp_set_keepalive(struct sock *sk, int val); 411 void tcp_syn_ack_timeout(const struct request_sock *req); 412 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 413 int flags, int *addr_len); 414 int tcp_set_rcvlowat(struct sock *sk, int val); 415 int tcp_set_window_clamp(struct sock *sk, int val); 416 void tcp_update_recv_tstamps(struct sk_buff *skb, 417 struct scm_timestamping_internal *tss); 418 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, 419 struct scm_timestamping_internal *tss); 420 void tcp_data_ready(struct sock *sk); 421 #ifdef CONFIG_MMU 422 int tcp_mmap(struct file *file, struct socket *sock, 423 struct vm_area_struct *vma); 424 #endif 425 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 426 struct tcp_options_received *opt_rx, 427 int estab, struct tcp_fastopen_cookie *foc); 428 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); 429 430 /* 431 * BPF SKB-less helpers 432 */ 433 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 434 struct tcphdr *th, u32 *cookie); 435 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 436 struct tcphdr *th, u32 *cookie); 437 u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss); 438 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 439 const struct tcp_request_sock_ops *af_ops, 440 struct sock *sk, struct tcphdr *th); 441 /* 442 * TCP v4 functions exported for the inet6 API 443 */ 444 445 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 446 void tcp_v4_mtu_reduced(struct sock *sk); 447 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 448 void tcp_ld_RTO_revert(struct sock *sk, u32 seq); 449 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 450 struct sock *tcp_create_openreq_child(const struct sock *sk, 451 struct request_sock *req, 452 struct sk_buff *skb); 453 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 454 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 455 struct request_sock *req, 456 struct dst_entry *dst, 457 struct request_sock *req_unhash, 458 bool *own_req); 459 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 460 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 461 int tcp_connect(struct sock *sk); 462 enum tcp_synack_type { 463 TCP_SYNACK_NORMAL, 464 TCP_SYNACK_FASTOPEN, 465 TCP_SYNACK_COOKIE, 466 }; 467 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 468 struct request_sock *req, 469 struct tcp_fastopen_cookie *foc, 470 enum tcp_synack_type synack_type, 471 struct sk_buff *syn_skb); 472 int tcp_disconnect(struct sock *sk, int flags); 473 474 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 475 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 476 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 477 478 /* From syncookies.c */ 479 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 480 struct request_sock *req, 481 struct dst_entry *dst, u32 tsoff); 482 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, 483 u32 cookie); 484 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 485 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops, 486 const struct tcp_request_sock_ops *af_ops, 487 struct sock *sk, struct sk_buff *skb); 488 #ifdef CONFIG_SYN_COOKIES 489 490 /* Syncookies use a monotonic timer which increments every 60 seconds. 491 * This counter is used both as a hash input and partially encoded into 492 * the cookie value. A cookie is only validated further if the delta 493 * between the current counter value and the encoded one is less than this, 494 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 495 * the counter advances immediately after a cookie is generated). 496 */ 497 #define MAX_SYNCOOKIE_AGE 2 498 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 499 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 500 501 /* syncookies: remember time of last synqueue overflow 502 * But do not dirty this field too often (once per second is enough) 503 * It is racy as we do not hold a lock, but race is very minor. 504 */ 505 static inline void tcp_synq_overflow(const struct sock *sk) 506 { 507 unsigned int last_overflow; 508 unsigned int now = jiffies; 509 510 if (sk->sk_reuseport) { 511 struct sock_reuseport *reuse; 512 513 reuse = rcu_dereference(sk->sk_reuseport_cb); 514 if (likely(reuse)) { 515 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 516 if (!time_between32(now, last_overflow, 517 last_overflow + HZ)) 518 WRITE_ONCE(reuse->synq_overflow_ts, now); 519 return; 520 } 521 } 522 523 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 524 if (!time_between32(now, last_overflow, last_overflow + HZ)) 525 WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now); 526 } 527 528 /* syncookies: no recent synqueue overflow on this listening socket? */ 529 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 530 { 531 unsigned int last_overflow; 532 unsigned int now = jiffies; 533 534 if (sk->sk_reuseport) { 535 struct sock_reuseport *reuse; 536 537 reuse = rcu_dereference(sk->sk_reuseport_cb); 538 if (likely(reuse)) { 539 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 540 return !time_between32(now, last_overflow - HZ, 541 last_overflow + 542 TCP_SYNCOOKIE_VALID); 543 } 544 } 545 546 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 547 548 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 549 * then we're under synflood. However, we have to use 550 * 'last_overflow - HZ' as lower bound. That's because a concurrent 551 * tcp_synq_overflow() could update .ts_recent_stamp after we read 552 * jiffies but before we store .ts_recent_stamp into last_overflow, 553 * which could lead to rejecting a valid syncookie. 554 */ 555 return !time_between32(now, last_overflow - HZ, 556 last_overflow + TCP_SYNCOOKIE_VALID); 557 } 558 559 static inline u32 tcp_cookie_time(void) 560 { 561 u64 val = get_jiffies_64(); 562 563 do_div(val, TCP_SYNCOOKIE_PERIOD); 564 return val; 565 } 566 567 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 568 u16 *mssp); 569 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 570 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 571 bool cookie_timestamp_decode(const struct net *net, 572 struct tcp_options_received *opt); 573 bool cookie_ecn_ok(const struct tcp_options_received *opt, 574 const struct net *net, const struct dst_entry *dst); 575 576 /* From net/ipv6/syncookies.c */ 577 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, 578 u32 cookie); 579 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 580 581 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 582 const struct tcphdr *th, u16 *mssp); 583 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 584 #endif 585 /* tcp_output.c */ 586 587 void tcp_skb_entail(struct sock *sk, struct sk_buff *skb); 588 void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb); 589 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 590 int nonagle); 591 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 592 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 593 void tcp_retransmit_timer(struct sock *sk); 594 void tcp_xmit_retransmit_queue(struct sock *); 595 void tcp_simple_retransmit(struct sock *); 596 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 597 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 598 enum tcp_queue { 599 TCP_FRAG_IN_WRITE_QUEUE, 600 TCP_FRAG_IN_RTX_QUEUE, 601 }; 602 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 603 struct sk_buff *skb, u32 len, 604 unsigned int mss_now, gfp_t gfp); 605 606 void tcp_send_probe0(struct sock *); 607 void tcp_send_partial(struct sock *); 608 int tcp_write_wakeup(struct sock *, int mib); 609 void tcp_send_fin(struct sock *sk); 610 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 611 int tcp_send_synack(struct sock *); 612 void tcp_push_one(struct sock *, unsigned int mss_now); 613 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 614 void tcp_send_ack(struct sock *sk); 615 void tcp_send_delayed_ack(struct sock *sk); 616 void tcp_send_loss_probe(struct sock *sk); 617 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 618 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 619 const struct sk_buff *next_skb); 620 621 /* tcp_input.c */ 622 void tcp_rearm_rto(struct sock *sk); 623 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 624 void tcp_reset(struct sock *sk, struct sk_buff *skb); 625 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb); 626 void tcp_fin(struct sock *sk); 627 void tcp_check_space(struct sock *sk); 628 629 /* tcp_timer.c */ 630 void tcp_init_xmit_timers(struct sock *); 631 static inline void tcp_clear_xmit_timers(struct sock *sk) 632 { 633 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 634 __sock_put(sk); 635 636 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 637 __sock_put(sk); 638 639 inet_csk_clear_xmit_timers(sk); 640 } 641 642 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 643 unsigned int tcp_current_mss(struct sock *sk); 644 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 645 646 /* Bound MSS / TSO packet size with the half of the window */ 647 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 648 { 649 int cutoff; 650 651 /* When peer uses tiny windows, there is no use in packetizing 652 * to sub-MSS pieces for the sake of SWS or making sure there 653 * are enough packets in the pipe for fast recovery. 654 * 655 * On the other hand, for extremely large MSS devices, handling 656 * smaller than MSS windows in this way does make sense. 657 */ 658 if (tp->max_window > TCP_MSS_DEFAULT) 659 cutoff = (tp->max_window >> 1); 660 else 661 cutoff = tp->max_window; 662 663 if (cutoff && pktsize > cutoff) 664 return max_t(int, cutoff, 68U - tp->tcp_header_len); 665 else 666 return pktsize; 667 } 668 669 /* tcp.c */ 670 void tcp_get_info(struct sock *, struct tcp_info *); 671 672 /* Read 'sendfile()'-style from a TCP socket */ 673 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 674 sk_read_actor_t recv_actor); 675 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 676 677 void tcp_initialize_rcv_mss(struct sock *sk); 678 679 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 680 int tcp_mss_to_mtu(struct sock *sk, int mss); 681 void tcp_mtup_init(struct sock *sk); 682 683 static inline void tcp_bound_rto(const struct sock *sk) 684 { 685 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 686 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 687 } 688 689 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 690 { 691 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 692 } 693 694 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 695 { 696 /* mptcp hooks are only on the slow path */ 697 if (sk_is_mptcp((struct sock *)tp)) 698 return; 699 700 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 701 ntohl(TCP_FLAG_ACK) | 702 snd_wnd); 703 } 704 705 static inline void tcp_fast_path_on(struct tcp_sock *tp) 706 { 707 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 708 } 709 710 static inline void tcp_fast_path_check(struct sock *sk) 711 { 712 struct tcp_sock *tp = tcp_sk(sk); 713 714 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 715 tp->rcv_wnd && 716 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 717 !tp->urg_data) 718 tcp_fast_path_on(tp); 719 } 720 721 /* Compute the actual rto_min value */ 722 static inline u32 tcp_rto_min(struct sock *sk) 723 { 724 const struct dst_entry *dst = __sk_dst_get(sk); 725 u32 rto_min = inet_csk(sk)->icsk_rto_min; 726 727 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 728 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 729 return rto_min; 730 } 731 732 static inline u32 tcp_rto_min_us(struct sock *sk) 733 { 734 return jiffies_to_usecs(tcp_rto_min(sk)); 735 } 736 737 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 738 { 739 return dst_metric_locked(dst, RTAX_CC_ALGO); 740 } 741 742 /* Minimum RTT in usec. ~0 means not available. */ 743 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 744 { 745 return minmax_get(&tp->rtt_min); 746 } 747 748 /* Compute the actual receive window we are currently advertising. 749 * Rcv_nxt can be after the window if our peer push more data 750 * than the offered window. 751 */ 752 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 753 { 754 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 755 756 if (win < 0) 757 win = 0; 758 return (u32) win; 759 } 760 761 /* Choose a new window, without checks for shrinking, and without 762 * scaling applied to the result. The caller does these things 763 * if necessary. This is a "raw" window selection. 764 */ 765 u32 __tcp_select_window(struct sock *sk); 766 767 void tcp_send_window_probe(struct sock *sk); 768 769 /* TCP uses 32bit jiffies to save some space. 770 * Note that this is different from tcp_time_stamp, which 771 * historically has been the same until linux-4.13. 772 */ 773 #define tcp_jiffies32 ((u32)jiffies) 774 775 /* 776 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 777 * It is no longer tied to jiffies, but to 1 ms clock. 778 * Note: double check if you want to use tcp_jiffies32 instead of this. 779 */ 780 #define TCP_TS_HZ 1000 781 782 static inline u64 tcp_clock_ns(void) 783 { 784 return ktime_get_ns(); 785 } 786 787 static inline u64 tcp_clock_us(void) 788 { 789 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 790 } 791 792 /* This should only be used in contexts where tp->tcp_mstamp is up to date */ 793 static inline u32 tcp_time_stamp(const struct tcp_sock *tp) 794 { 795 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); 796 } 797 798 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ 799 static inline u32 tcp_ns_to_ts(u64 ns) 800 { 801 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); 802 } 803 804 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ 805 static inline u32 tcp_time_stamp_raw(void) 806 { 807 return tcp_ns_to_ts(tcp_clock_ns()); 808 } 809 810 void tcp_mstamp_refresh(struct tcp_sock *tp); 811 812 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 813 { 814 return max_t(s64, t1 - t0, 0); 815 } 816 817 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 818 { 819 return tcp_ns_to_ts(skb->skb_mstamp_ns); 820 } 821 822 /* provide the departure time in us unit */ 823 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 824 { 825 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 826 } 827 828 829 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 830 831 #define TCPHDR_FIN 0x01 832 #define TCPHDR_SYN 0x02 833 #define TCPHDR_RST 0x04 834 #define TCPHDR_PSH 0x08 835 #define TCPHDR_ACK 0x10 836 #define TCPHDR_URG 0x20 837 #define TCPHDR_ECE 0x40 838 #define TCPHDR_CWR 0x80 839 840 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 841 842 /* This is what the send packet queuing engine uses to pass 843 * TCP per-packet control information to the transmission code. 844 * We also store the host-order sequence numbers in here too. 845 * This is 44 bytes if IPV6 is enabled. 846 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 847 */ 848 struct tcp_skb_cb { 849 __u32 seq; /* Starting sequence number */ 850 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 851 union { 852 /* Note : tcp_tw_isn is used in input path only 853 * (isn chosen by tcp_timewait_state_process()) 854 * 855 * tcp_gso_segs/size are used in write queue only, 856 * cf tcp_skb_pcount()/tcp_skb_mss() 857 */ 858 __u32 tcp_tw_isn; 859 struct { 860 u16 tcp_gso_segs; 861 u16 tcp_gso_size; 862 }; 863 }; 864 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 865 866 __u8 sacked; /* State flags for SACK. */ 867 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 868 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 869 #define TCPCB_LOST 0x04 /* SKB is lost */ 870 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 871 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 872 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 873 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 874 TCPCB_REPAIRED) 875 876 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 877 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 878 eor:1, /* Is skb MSG_EOR marked? */ 879 has_rxtstamp:1, /* SKB has a RX timestamp */ 880 unused:5; 881 __u32 ack_seq; /* Sequence number ACK'd */ 882 union { 883 struct { 884 #define TCPCB_DELIVERED_CE_MASK ((1U<<20) - 1) 885 /* There is space for up to 24 bytes */ 886 __u32 is_app_limited:1, /* cwnd not fully used? */ 887 delivered_ce:20, 888 unused:11; 889 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 890 __u32 delivered; 891 /* start of send pipeline phase */ 892 u64 first_tx_mstamp; 893 /* when we reached the "delivered" count */ 894 u64 delivered_mstamp; 895 } tx; /* only used for outgoing skbs */ 896 union { 897 struct inet_skb_parm h4; 898 #if IS_ENABLED(CONFIG_IPV6) 899 struct inet6_skb_parm h6; 900 #endif 901 } header; /* For incoming skbs */ 902 }; 903 }; 904 905 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 906 907 extern const struct inet_connection_sock_af_ops ipv4_specific; 908 909 #if IS_ENABLED(CONFIG_IPV6) 910 /* This is the variant of inet6_iif() that must be used by TCP, 911 * as TCP moves IP6CB into a different location in skb->cb[] 912 */ 913 static inline int tcp_v6_iif(const struct sk_buff *skb) 914 { 915 return TCP_SKB_CB(skb)->header.h6.iif; 916 } 917 918 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 919 { 920 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 921 922 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 923 } 924 925 /* TCP_SKB_CB reference means this can not be used from early demux */ 926 static inline int tcp_v6_sdif(const struct sk_buff *skb) 927 { 928 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 929 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 930 return TCP_SKB_CB(skb)->header.h6.iif; 931 #endif 932 return 0; 933 } 934 935 extern const struct inet_connection_sock_af_ops ipv6_specific; 936 937 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 938 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 939 void tcp_v6_early_demux(struct sk_buff *skb); 940 941 #endif 942 943 /* TCP_SKB_CB reference means this can not be used from early demux */ 944 static inline int tcp_v4_sdif(struct sk_buff *skb) 945 { 946 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 947 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 948 return TCP_SKB_CB(skb)->header.h4.iif; 949 #endif 950 return 0; 951 } 952 953 /* Due to TSO, an SKB can be composed of multiple actual 954 * packets. To keep these tracked properly, we use this. 955 */ 956 static inline int tcp_skb_pcount(const struct sk_buff *skb) 957 { 958 return TCP_SKB_CB(skb)->tcp_gso_segs; 959 } 960 961 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 962 { 963 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 964 } 965 966 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 967 { 968 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 969 } 970 971 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 972 static inline int tcp_skb_mss(const struct sk_buff *skb) 973 { 974 return TCP_SKB_CB(skb)->tcp_gso_size; 975 } 976 977 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 978 { 979 return likely(!TCP_SKB_CB(skb)->eor); 980 } 981 982 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 983 const struct sk_buff *from) 984 { 985 return likely(tcp_skb_can_collapse_to(to) && 986 mptcp_skb_can_collapse(to, from) && 987 skb_pure_zcopy_same(to, from)); 988 } 989 990 /* Events passed to congestion control interface */ 991 enum tcp_ca_event { 992 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 993 CA_EVENT_CWND_RESTART, /* congestion window restart */ 994 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 995 CA_EVENT_LOSS, /* loss timeout */ 996 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 997 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 998 }; 999 1000 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1001 enum tcp_ca_ack_event_flags { 1002 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1003 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1004 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1005 }; 1006 1007 /* 1008 * Interface for adding new TCP congestion control handlers 1009 */ 1010 #define TCP_CA_NAME_MAX 16 1011 #define TCP_CA_MAX 128 1012 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1013 1014 #define TCP_CA_UNSPEC 0 1015 1016 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1017 #define TCP_CONG_NON_RESTRICTED 0x1 1018 /* Requires ECN/ECT set on all packets */ 1019 #define TCP_CONG_NEEDS_ECN 0x2 1020 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1021 1022 union tcp_cc_info; 1023 1024 struct ack_sample { 1025 u32 pkts_acked; 1026 s32 rtt_us; 1027 u32 in_flight; 1028 }; 1029 1030 /* A rate sample measures the number of (original/retransmitted) data 1031 * packets delivered "delivered" over an interval of time "interval_us". 1032 * The tcp_rate.c code fills in the rate sample, and congestion 1033 * control modules that define a cong_control function to run at the end 1034 * of ACK processing can optionally chose to consult this sample when 1035 * setting cwnd and pacing rate. 1036 * A sample is invalid if "delivered" or "interval_us" is negative. 1037 */ 1038 struct rate_sample { 1039 u64 prior_mstamp; /* starting timestamp for interval */ 1040 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1041 u32 prior_delivered_ce;/* tp->delivered_ce at "prior_mstamp" */ 1042 s32 delivered; /* number of packets delivered over interval */ 1043 s32 delivered_ce; /* number of packets delivered w/ CE marks*/ 1044 long interval_us; /* time for tp->delivered to incr "delivered" */ 1045 u32 snd_interval_us; /* snd interval for delivered packets */ 1046 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1047 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1048 int losses; /* number of packets marked lost upon ACK */ 1049 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1050 u32 prior_in_flight; /* in flight before this ACK */ 1051 u32 last_end_seq; /* end_seq of most recently ACKed packet */ 1052 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1053 bool is_retrans; /* is sample from retransmission? */ 1054 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1055 }; 1056 1057 struct tcp_congestion_ops { 1058 /* fast path fields are put first to fill one cache line */ 1059 1060 /* return slow start threshold (required) */ 1061 u32 (*ssthresh)(struct sock *sk); 1062 1063 /* do new cwnd calculation (required) */ 1064 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1065 1066 /* call before changing ca_state (optional) */ 1067 void (*set_state)(struct sock *sk, u8 new_state); 1068 1069 /* call when cwnd event occurs (optional) */ 1070 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1071 1072 /* call when ack arrives (optional) */ 1073 void (*in_ack_event)(struct sock *sk, u32 flags); 1074 1075 /* hook for packet ack accounting (optional) */ 1076 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1077 1078 /* override sysctl_tcp_min_tso_segs */ 1079 u32 (*min_tso_segs)(struct sock *sk); 1080 1081 /* call when packets are delivered to update cwnd and pacing rate, 1082 * after all the ca_state processing. (optional) 1083 */ 1084 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1085 1086 1087 /* new value of cwnd after loss (required) */ 1088 u32 (*undo_cwnd)(struct sock *sk); 1089 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1090 u32 (*sndbuf_expand)(struct sock *sk); 1091 1092 /* control/slow paths put last */ 1093 /* get info for inet_diag (optional) */ 1094 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1095 union tcp_cc_info *info); 1096 1097 char name[TCP_CA_NAME_MAX]; 1098 struct module *owner; 1099 struct list_head list; 1100 u32 key; 1101 u32 flags; 1102 1103 /* initialize private data (optional) */ 1104 void (*init)(struct sock *sk); 1105 /* cleanup private data (optional) */ 1106 void (*release)(struct sock *sk); 1107 } ____cacheline_aligned_in_smp; 1108 1109 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1110 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1111 1112 void tcp_assign_congestion_control(struct sock *sk); 1113 void tcp_init_congestion_control(struct sock *sk); 1114 void tcp_cleanup_congestion_control(struct sock *sk); 1115 int tcp_set_default_congestion_control(struct net *net, const char *name); 1116 void tcp_get_default_congestion_control(struct net *net, char *name); 1117 void tcp_get_available_congestion_control(char *buf, size_t len); 1118 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1119 int tcp_set_allowed_congestion_control(char *allowed); 1120 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1121 bool cap_net_admin); 1122 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1123 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1124 1125 u32 tcp_reno_ssthresh(struct sock *sk); 1126 u32 tcp_reno_undo_cwnd(struct sock *sk); 1127 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1128 extern struct tcp_congestion_ops tcp_reno; 1129 1130 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1131 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1132 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1133 #ifdef CONFIG_INET 1134 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1135 #else 1136 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1137 { 1138 return NULL; 1139 } 1140 #endif 1141 1142 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1143 { 1144 const struct inet_connection_sock *icsk = inet_csk(sk); 1145 1146 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1147 } 1148 1149 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1150 { 1151 const struct inet_connection_sock *icsk = inet_csk(sk); 1152 1153 if (icsk->icsk_ca_ops->cwnd_event) 1154 icsk->icsk_ca_ops->cwnd_event(sk, event); 1155 } 1156 1157 /* From tcp_cong.c */ 1158 void tcp_set_ca_state(struct sock *sk, const u8 ca_state); 1159 1160 /* From tcp_rate.c */ 1161 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1162 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1163 struct rate_sample *rs); 1164 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1165 bool is_sack_reneg, struct rate_sample *rs); 1166 void tcp_rate_check_app_limited(struct sock *sk); 1167 1168 static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2) 1169 { 1170 return t1 > t2 || (t1 == t2 && after(seq1, seq2)); 1171 } 1172 1173 /* These functions determine how the current flow behaves in respect of SACK 1174 * handling. SACK is negotiated with the peer, and therefore it can vary 1175 * between different flows. 1176 * 1177 * tcp_is_sack - SACK enabled 1178 * tcp_is_reno - No SACK 1179 */ 1180 static inline int tcp_is_sack(const struct tcp_sock *tp) 1181 { 1182 return likely(tp->rx_opt.sack_ok); 1183 } 1184 1185 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1186 { 1187 return !tcp_is_sack(tp); 1188 } 1189 1190 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1191 { 1192 return tp->sacked_out + tp->lost_out; 1193 } 1194 1195 /* This determines how many packets are "in the network" to the best 1196 * of our knowledge. In many cases it is conservative, but where 1197 * detailed information is available from the receiver (via SACK 1198 * blocks etc.) we can make more aggressive calculations. 1199 * 1200 * Use this for decisions involving congestion control, use just 1201 * tp->packets_out to determine if the send queue is empty or not. 1202 * 1203 * Read this equation as: 1204 * 1205 * "Packets sent once on transmission queue" MINUS 1206 * "Packets left network, but not honestly ACKed yet" PLUS 1207 * "Packets fast retransmitted" 1208 */ 1209 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1210 { 1211 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1212 } 1213 1214 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1215 1216 static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp) 1217 { 1218 return tp->snd_cwnd; 1219 } 1220 1221 static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val) 1222 { 1223 WARN_ON_ONCE((int)val <= 0); 1224 tp->snd_cwnd = val; 1225 } 1226 1227 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1228 { 1229 return tcp_snd_cwnd(tp) < tp->snd_ssthresh; 1230 } 1231 1232 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1233 { 1234 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1235 } 1236 1237 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1238 { 1239 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1240 (1 << inet_csk(sk)->icsk_ca_state); 1241 } 1242 1243 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1244 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1245 * ssthresh. 1246 */ 1247 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1248 { 1249 const struct tcp_sock *tp = tcp_sk(sk); 1250 1251 if (tcp_in_cwnd_reduction(sk)) 1252 return tp->snd_ssthresh; 1253 else 1254 return max(tp->snd_ssthresh, 1255 ((tcp_snd_cwnd(tp) >> 1) + 1256 (tcp_snd_cwnd(tp) >> 2))); 1257 } 1258 1259 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1260 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1261 1262 void tcp_enter_cwr(struct sock *sk); 1263 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1264 1265 /* The maximum number of MSS of available cwnd for which TSO defers 1266 * sending if not using sysctl_tcp_tso_win_divisor. 1267 */ 1268 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1269 { 1270 return 3; 1271 } 1272 1273 /* Returns end sequence number of the receiver's advertised window */ 1274 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1275 { 1276 return tp->snd_una + tp->snd_wnd; 1277 } 1278 1279 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1280 * flexible approach. The RFC suggests cwnd should not be raised unless 1281 * it was fully used previously. And that's exactly what we do in 1282 * congestion avoidance mode. But in slow start we allow cwnd to grow 1283 * as long as the application has used half the cwnd. 1284 * Example : 1285 * cwnd is 10 (IW10), but application sends 9 frames. 1286 * We allow cwnd to reach 18 when all frames are ACKed. 1287 * This check is safe because it's as aggressive as slow start which already 1288 * risks 100% overshoot. The advantage is that we discourage application to 1289 * either send more filler packets or data to artificially blow up the cwnd 1290 * usage, and allow application-limited process to probe bw more aggressively. 1291 */ 1292 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1293 { 1294 const struct tcp_sock *tp = tcp_sk(sk); 1295 1296 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1297 if (tcp_in_slow_start(tp)) 1298 return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out; 1299 1300 return tp->is_cwnd_limited; 1301 } 1302 1303 /* BBR congestion control needs pacing. 1304 * Same remark for SO_MAX_PACING_RATE. 1305 * sch_fq packet scheduler is efficiently handling pacing, 1306 * but is not always installed/used. 1307 * Return true if TCP stack should pace packets itself. 1308 */ 1309 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1310 { 1311 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1312 } 1313 1314 /* Estimates in how many jiffies next packet for this flow can be sent. 1315 * Scheduling a retransmit timer too early would be silly. 1316 */ 1317 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1318 { 1319 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1320 1321 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1322 } 1323 1324 static inline void tcp_reset_xmit_timer(struct sock *sk, 1325 const int what, 1326 unsigned long when, 1327 const unsigned long max_when) 1328 { 1329 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk), 1330 max_when); 1331 } 1332 1333 /* Something is really bad, we could not queue an additional packet, 1334 * because qdisc is full or receiver sent a 0 window, or we are paced. 1335 * We do not want to add fuel to the fire, or abort too early, 1336 * so make sure the timer we arm now is at least 200ms in the future, 1337 * regardless of current icsk_rto value (as it could be ~2ms) 1338 */ 1339 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1340 { 1341 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1342 } 1343 1344 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1345 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1346 unsigned long max_when) 1347 { 1348 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1349 inet_csk(sk)->icsk_backoff); 1350 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1351 1352 return (unsigned long)min_t(u64, when, max_when); 1353 } 1354 1355 static inline void tcp_check_probe_timer(struct sock *sk) 1356 { 1357 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1358 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1359 tcp_probe0_base(sk), TCP_RTO_MAX); 1360 } 1361 1362 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1363 { 1364 tp->snd_wl1 = seq; 1365 } 1366 1367 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1368 { 1369 tp->snd_wl1 = seq; 1370 } 1371 1372 /* 1373 * Calculate(/check) TCP checksum 1374 */ 1375 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1376 __be32 daddr, __wsum base) 1377 { 1378 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1379 } 1380 1381 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1382 { 1383 return !skb_csum_unnecessary(skb) && 1384 __skb_checksum_complete(skb); 1385 } 1386 1387 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1388 enum skb_drop_reason *reason); 1389 1390 1391 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1392 void tcp_set_state(struct sock *sk, int state); 1393 void tcp_done(struct sock *sk); 1394 int tcp_abort(struct sock *sk, int err); 1395 1396 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1397 { 1398 rx_opt->dsack = 0; 1399 rx_opt->num_sacks = 0; 1400 } 1401 1402 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1403 1404 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1405 { 1406 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1407 struct tcp_sock *tp = tcp_sk(sk); 1408 s32 delta; 1409 1410 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) || 1411 tp->packets_out || ca_ops->cong_control) 1412 return; 1413 delta = tcp_jiffies32 - tp->lsndtime; 1414 if (delta > inet_csk(sk)->icsk_rto) 1415 tcp_cwnd_restart(sk, delta); 1416 } 1417 1418 /* Determine a window scaling and initial window to offer. */ 1419 void tcp_select_initial_window(const struct sock *sk, int __space, 1420 __u32 mss, __u32 *rcv_wnd, 1421 __u32 *window_clamp, int wscale_ok, 1422 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1423 1424 static inline int tcp_win_from_space(const struct sock *sk, int space) 1425 { 1426 int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; 1427 1428 return tcp_adv_win_scale <= 0 ? 1429 (space>>(-tcp_adv_win_scale)) : 1430 space - (space>>tcp_adv_win_scale); 1431 } 1432 1433 /* Note: caller must be prepared to deal with negative returns */ 1434 static inline int tcp_space(const struct sock *sk) 1435 { 1436 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1437 READ_ONCE(sk->sk_backlog.len) - 1438 atomic_read(&sk->sk_rmem_alloc)); 1439 } 1440 1441 static inline int tcp_full_space(const struct sock *sk) 1442 { 1443 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1444 } 1445 1446 static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) 1447 { 1448 int unused_mem = sk_unused_reserved_mem(sk); 1449 struct tcp_sock *tp = tcp_sk(sk); 1450 1451 tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss); 1452 if (unused_mem) 1453 tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh, 1454 tcp_win_from_space(sk, unused_mem)); 1455 } 1456 1457 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1458 1459 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1460 * If 87.5 % (7/8) of the space has been consumed, we want to override 1461 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1462 * len/truesize ratio. 1463 */ 1464 static inline bool tcp_rmem_pressure(const struct sock *sk) 1465 { 1466 int rcvbuf, threshold; 1467 1468 if (tcp_under_memory_pressure(sk)) 1469 return true; 1470 1471 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1472 threshold = rcvbuf - (rcvbuf >> 3); 1473 1474 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1475 } 1476 1477 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1478 { 1479 const struct tcp_sock *tp = tcp_sk(sk); 1480 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1481 1482 if (avail <= 0) 1483 return false; 1484 1485 return (avail >= target) || tcp_rmem_pressure(sk) || 1486 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1487 } 1488 1489 extern void tcp_openreq_init_rwin(struct request_sock *req, 1490 const struct sock *sk_listener, 1491 const struct dst_entry *dst); 1492 1493 void tcp_enter_memory_pressure(struct sock *sk); 1494 void tcp_leave_memory_pressure(struct sock *sk); 1495 1496 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1497 { 1498 struct net *net = sock_net((struct sock *)tp); 1499 1500 return tp->keepalive_intvl ? : 1501 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); 1502 } 1503 1504 static inline int keepalive_time_when(const struct tcp_sock *tp) 1505 { 1506 struct net *net = sock_net((struct sock *)tp); 1507 1508 return tp->keepalive_time ? : 1509 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); 1510 } 1511 1512 static inline int keepalive_probes(const struct tcp_sock *tp) 1513 { 1514 struct net *net = sock_net((struct sock *)tp); 1515 1516 return tp->keepalive_probes ? : 1517 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); 1518 } 1519 1520 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1521 { 1522 const struct inet_connection_sock *icsk = &tp->inet_conn; 1523 1524 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1525 tcp_jiffies32 - tp->rcv_tstamp); 1526 } 1527 1528 static inline int tcp_fin_time(const struct sock *sk) 1529 { 1530 int fin_timeout = tcp_sk(sk)->linger2 ? : 1531 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); 1532 const int rto = inet_csk(sk)->icsk_rto; 1533 1534 if (fin_timeout < (rto << 2) - (rto >> 1)) 1535 fin_timeout = (rto << 2) - (rto >> 1); 1536 1537 return fin_timeout; 1538 } 1539 1540 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1541 int paws_win) 1542 { 1543 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1544 return true; 1545 if (unlikely(!time_before32(ktime_get_seconds(), 1546 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1547 return true; 1548 /* 1549 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1550 * then following tcp messages have valid values. Ignore 0 value, 1551 * or else 'negative' tsval might forbid us to accept their packets. 1552 */ 1553 if (!rx_opt->ts_recent) 1554 return true; 1555 return false; 1556 } 1557 1558 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1559 int rst) 1560 { 1561 if (tcp_paws_check(rx_opt, 0)) 1562 return false; 1563 1564 /* RST segments are not recommended to carry timestamp, 1565 and, if they do, it is recommended to ignore PAWS because 1566 "their cleanup function should take precedence over timestamps." 1567 Certainly, it is mistake. It is necessary to understand the reasons 1568 of this constraint to relax it: if peer reboots, clock may go 1569 out-of-sync and half-open connections will not be reset. 1570 Actually, the problem would be not existing if all 1571 the implementations followed draft about maintaining clock 1572 via reboots. Linux-2.2 DOES NOT! 1573 1574 However, we can relax time bounds for RST segments to MSL. 1575 */ 1576 if (rst && !time_before32(ktime_get_seconds(), 1577 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1578 return false; 1579 return true; 1580 } 1581 1582 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1583 int mib_idx, u32 *last_oow_ack_time); 1584 1585 static inline void tcp_mib_init(struct net *net) 1586 { 1587 /* See RFC 2012 */ 1588 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1589 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1590 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1591 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1592 } 1593 1594 /* from STCP */ 1595 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1596 { 1597 tp->lost_skb_hint = NULL; 1598 } 1599 1600 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1601 { 1602 tcp_clear_retrans_hints_partial(tp); 1603 tp->retransmit_skb_hint = NULL; 1604 } 1605 1606 union tcp_md5_addr { 1607 struct in_addr a4; 1608 #if IS_ENABLED(CONFIG_IPV6) 1609 struct in6_addr a6; 1610 #endif 1611 }; 1612 1613 /* - key database */ 1614 struct tcp_md5sig_key { 1615 struct hlist_node node; 1616 u8 keylen; 1617 u8 family; /* AF_INET or AF_INET6 */ 1618 u8 prefixlen; 1619 u8 flags; 1620 union tcp_md5_addr addr; 1621 int l3index; /* set if key added with L3 scope */ 1622 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1623 struct rcu_head rcu; 1624 }; 1625 1626 /* - sock block */ 1627 struct tcp_md5sig_info { 1628 struct hlist_head head; 1629 struct rcu_head rcu; 1630 }; 1631 1632 /* - pseudo header */ 1633 struct tcp4_pseudohdr { 1634 __be32 saddr; 1635 __be32 daddr; 1636 __u8 pad; 1637 __u8 protocol; 1638 __be16 len; 1639 }; 1640 1641 struct tcp6_pseudohdr { 1642 struct in6_addr saddr; 1643 struct in6_addr daddr; 1644 __be32 len; 1645 __be32 protocol; /* including padding */ 1646 }; 1647 1648 union tcp_md5sum_block { 1649 struct tcp4_pseudohdr ip4; 1650 #if IS_ENABLED(CONFIG_IPV6) 1651 struct tcp6_pseudohdr ip6; 1652 #endif 1653 }; 1654 1655 /* - pool: digest algorithm, hash description and scratch buffer */ 1656 struct tcp_md5sig_pool { 1657 struct ahash_request *md5_req; 1658 void *scratch; 1659 }; 1660 1661 /* - functions */ 1662 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1663 const struct sock *sk, const struct sk_buff *skb); 1664 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1665 int family, u8 prefixlen, int l3index, u8 flags, 1666 const u8 *newkey, u8 newkeylen, gfp_t gfp); 1667 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1668 int family, u8 prefixlen, int l3index, u8 flags); 1669 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1670 const struct sock *addr_sk); 1671 1672 #ifdef CONFIG_TCP_MD5SIG 1673 #include <linux/jump_label.h> 1674 extern struct static_key_false tcp_md5_needed; 1675 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1676 const union tcp_md5_addr *addr, 1677 int family); 1678 static inline struct tcp_md5sig_key * 1679 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1680 const union tcp_md5_addr *addr, int family) 1681 { 1682 if (!static_branch_unlikely(&tcp_md5_needed)) 1683 return NULL; 1684 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1685 } 1686 1687 enum skb_drop_reason 1688 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1689 const void *saddr, const void *daddr, 1690 int family, int dif, int sdif); 1691 1692 1693 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1694 #else 1695 static inline struct tcp_md5sig_key * 1696 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1697 const union tcp_md5_addr *addr, int family) 1698 { 1699 return NULL; 1700 } 1701 1702 static inline enum skb_drop_reason 1703 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1704 const void *saddr, const void *daddr, 1705 int family, int dif, int sdif) 1706 { 1707 return SKB_NOT_DROPPED_YET; 1708 } 1709 #define tcp_twsk_md5_key(twsk) NULL 1710 #endif 1711 1712 bool tcp_alloc_md5sig_pool(void); 1713 1714 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1715 static inline void tcp_put_md5sig_pool(void) 1716 { 1717 local_bh_enable(); 1718 } 1719 1720 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1721 unsigned int header_len); 1722 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1723 const struct tcp_md5sig_key *key); 1724 1725 /* From tcp_fastopen.c */ 1726 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1727 struct tcp_fastopen_cookie *cookie); 1728 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1729 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1730 u16 try_exp); 1731 struct tcp_fastopen_request { 1732 /* Fast Open cookie. Size 0 means a cookie request */ 1733 struct tcp_fastopen_cookie cookie; 1734 struct msghdr *data; /* data in MSG_FASTOPEN */ 1735 size_t size; 1736 int copied; /* queued in tcp_connect() */ 1737 struct ubuf_info *uarg; 1738 }; 1739 void tcp_free_fastopen_req(struct tcp_sock *tp); 1740 void tcp_fastopen_destroy_cipher(struct sock *sk); 1741 void tcp_fastopen_ctx_destroy(struct net *net); 1742 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1743 void *primary_key, void *backup_key); 1744 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1745 u64 *key); 1746 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1747 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1748 struct request_sock *req, 1749 struct tcp_fastopen_cookie *foc, 1750 const struct dst_entry *dst); 1751 void tcp_fastopen_init_key_once(struct net *net); 1752 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1753 struct tcp_fastopen_cookie *cookie); 1754 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1755 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1756 #define TCP_FASTOPEN_KEY_MAX 2 1757 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1758 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1759 1760 /* Fastopen key context */ 1761 struct tcp_fastopen_context { 1762 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1763 int num; 1764 struct rcu_head rcu; 1765 }; 1766 1767 void tcp_fastopen_active_disable(struct sock *sk); 1768 bool tcp_fastopen_active_should_disable(struct sock *sk); 1769 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1770 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1771 1772 /* Caller needs to wrap with rcu_read_(un)lock() */ 1773 static inline 1774 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1775 { 1776 struct tcp_fastopen_context *ctx; 1777 1778 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1779 if (!ctx) 1780 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1781 return ctx; 1782 } 1783 1784 static inline 1785 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1786 const struct tcp_fastopen_cookie *orig) 1787 { 1788 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1789 orig->len == foc->len && 1790 !memcmp(orig->val, foc->val, foc->len)) 1791 return true; 1792 return false; 1793 } 1794 1795 static inline 1796 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1797 { 1798 return ctx->num; 1799 } 1800 1801 /* Latencies incurred by various limits for a sender. They are 1802 * chronograph-like stats that are mutually exclusive. 1803 */ 1804 enum tcp_chrono { 1805 TCP_CHRONO_UNSPEC, 1806 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1807 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1808 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1809 __TCP_CHRONO_MAX, 1810 }; 1811 1812 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1813 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1814 1815 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1816 * the same memory storage than skb->destructor/_skb_refdst 1817 */ 1818 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1819 { 1820 skb->destructor = NULL; 1821 skb->_skb_refdst = 0UL; 1822 } 1823 1824 #define tcp_skb_tsorted_save(skb) { \ 1825 unsigned long _save = skb->_skb_refdst; \ 1826 skb->_skb_refdst = 0UL; 1827 1828 #define tcp_skb_tsorted_restore(skb) \ 1829 skb->_skb_refdst = _save; \ 1830 } 1831 1832 void tcp_write_queue_purge(struct sock *sk); 1833 1834 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1835 { 1836 return skb_rb_first(&sk->tcp_rtx_queue); 1837 } 1838 1839 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1840 { 1841 return skb_rb_last(&sk->tcp_rtx_queue); 1842 } 1843 1844 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1845 { 1846 return skb_peek_tail(&sk->sk_write_queue); 1847 } 1848 1849 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1850 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1851 1852 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1853 { 1854 return skb_peek(&sk->sk_write_queue); 1855 } 1856 1857 static inline bool tcp_skb_is_last(const struct sock *sk, 1858 const struct sk_buff *skb) 1859 { 1860 return skb_queue_is_last(&sk->sk_write_queue, skb); 1861 } 1862 1863 /** 1864 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1865 * @sk: socket 1866 * 1867 * Since the write queue can have a temporary empty skb in it, 1868 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1869 */ 1870 static inline bool tcp_write_queue_empty(const struct sock *sk) 1871 { 1872 const struct tcp_sock *tp = tcp_sk(sk); 1873 1874 return tp->write_seq == tp->snd_nxt; 1875 } 1876 1877 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1878 { 1879 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1880 } 1881 1882 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1883 { 1884 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1885 } 1886 1887 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1888 { 1889 __skb_queue_tail(&sk->sk_write_queue, skb); 1890 1891 /* Queue it, remembering where we must start sending. */ 1892 if (sk->sk_write_queue.next == skb) 1893 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1894 } 1895 1896 /* Insert new before skb on the write queue of sk. */ 1897 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1898 struct sk_buff *skb, 1899 struct sock *sk) 1900 { 1901 __skb_queue_before(&sk->sk_write_queue, skb, new); 1902 } 1903 1904 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1905 { 1906 tcp_skb_tsorted_anchor_cleanup(skb); 1907 __skb_unlink(skb, &sk->sk_write_queue); 1908 } 1909 1910 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1911 1912 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1913 { 1914 tcp_skb_tsorted_anchor_cleanup(skb); 1915 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1916 } 1917 1918 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1919 { 1920 list_del(&skb->tcp_tsorted_anchor); 1921 tcp_rtx_queue_unlink(skb, sk); 1922 tcp_wmem_free_skb(sk, skb); 1923 } 1924 1925 static inline void tcp_push_pending_frames(struct sock *sk) 1926 { 1927 if (tcp_send_head(sk)) { 1928 struct tcp_sock *tp = tcp_sk(sk); 1929 1930 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1931 } 1932 } 1933 1934 /* Start sequence of the skb just after the highest skb with SACKed 1935 * bit, valid only if sacked_out > 0 or when the caller has ensured 1936 * validity by itself. 1937 */ 1938 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1939 { 1940 if (!tp->sacked_out) 1941 return tp->snd_una; 1942 1943 if (tp->highest_sack == NULL) 1944 return tp->snd_nxt; 1945 1946 return TCP_SKB_CB(tp->highest_sack)->seq; 1947 } 1948 1949 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1950 { 1951 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 1952 } 1953 1954 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1955 { 1956 return tcp_sk(sk)->highest_sack; 1957 } 1958 1959 static inline void tcp_highest_sack_reset(struct sock *sk) 1960 { 1961 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 1962 } 1963 1964 /* Called when old skb is about to be deleted and replaced by new skb */ 1965 static inline void tcp_highest_sack_replace(struct sock *sk, 1966 struct sk_buff *old, 1967 struct sk_buff *new) 1968 { 1969 if (old == tcp_highest_sack(sk)) 1970 tcp_sk(sk)->highest_sack = new; 1971 } 1972 1973 /* This helper checks if socket has IP_TRANSPARENT set */ 1974 static inline bool inet_sk_transparent(const struct sock *sk) 1975 { 1976 switch (sk->sk_state) { 1977 case TCP_TIME_WAIT: 1978 return inet_twsk(sk)->tw_transparent; 1979 case TCP_NEW_SYN_RECV: 1980 return inet_rsk(inet_reqsk(sk))->no_srccheck; 1981 } 1982 return inet_sk(sk)->transparent; 1983 } 1984 1985 /* Determines whether this is a thin stream (which may suffer from 1986 * increased latency). Used to trigger latency-reducing mechanisms. 1987 */ 1988 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 1989 { 1990 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 1991 } 1992 1993 /* /proc */ 1994 enum tcp_seq_states { 1995 TCP_SEQ_STATE_LISTENING, 1996 TCP_SEQ_STATE_ESTABLISHED, 1997 }; 1998 1999 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 2000 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 2001 void tcp_seq_stop(struct seq_file *seq, void *v); 2002 2003 struct tcp_seq_afinfo { 2004 sa_family_t family; 2005 }; 2006 2007 struct tcp_iter_state { 2008 struct seq_net_private p; 2009 enum tcp_seq_states state; 2010 struct sock *syn_wait_sk; 2011 int bucket, offset, sbucket, num; 2012 loff_t last_pos; 2013 }; 2014 2015 extern struct request_sock_ops tcp_request_sock_ops; 2016 extern struct request_sock_ops tcp6_request_sock_ops; 2017 2018 void tcp_v4_destroy_sock(struct sock *sk); 2019 2020 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 2021 netdev_features_t features); 2022 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 2023 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 2024 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 2025 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 2026 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 2027 int tcp_gro_complete(struct sk_buff *skb); 2028 2029 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 2030 2031 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 2032 { 2033 struct net *net = sock_net((struct sock *)tp); 2034 return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); 2035 } 2036 2037 bool tcp_stream_memory_free(const struct sock *sk, int wake); 2038 2039 #ifdef CONFIG_PROC_FS 2040 int tcp4_proc_init(void); 2041 void tcp4_proc_exit(void); 2042 #endif 2043 2044 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2045 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2046 const struct tcp_request_sock_ops *af_ops, 2047 struct sock *sk, struct sk_buff *skb); 2048 2049 /* TCP af-specific functions */ 2050 struct tcp_sock_af_ops { 2051 #ifdef CONFIG_TCP_MD5SIG 2052 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2053 const struct sock *addr_sk); 2054 int (*calc_md5_hash)(char *location, 2055 const struct tcp_md5sig_key *md5, 2056 const struct sock *sk, 2057 const struct sk_buff *skb); 2058 int (*md5_parse)(struct sock *sk, 2059 int optname, 2060 sockptr_t optval, 2061 int optlen); 2062 #endif 2063 }; 2064 2065 struct tcp_request_sock_ops { 2066 u16 mss_clamp; 2067 #ifdef CONFIG_TCP_MD5SIG 2068 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2069 const struct sock *addr_sk); 2070 int (*calc_md5_hash) (char *location, 2071 const struct tcp_md5sig_key *md5, 2072 const struct sock *sk, 2073 const struct sk_buff *skb); 2074 #endif 2075 #ifdef CONFIG_SYN_COOKIES 2076 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2077 __u16 *mss); 2078 #endif 2079 struct dst_entry *(*route_req)(const struct sock *sk, 2080 struct sk_buff *skb, 2081 struct flowi *fl, 2082 struct request_sock *req); 2083 u32 (*init_seq)(const struct sk_buff *skb); 2084 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2085 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2086 struct flowi *fl, struct request_sock *req, 2087 struct tcp_fastopen_cookie *foc, 2088 enum tcp_synack_type synack_type, 2089 struct sk_buff *syn_skb); 2090 }; 2091 2092 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2093 #if IS_ENABLED(CONFIG_IPV6) 2094 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2095 #endif 2096 2097 #ifdef CONFIG_SYN_COOKIES 2098 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2099 const struct sock *sk, struct sk_buff *skb, 2100 __u16 *mss) 2101 { 2102 tcp_synq_overflow(sk); 2103 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2104 return ops->cookie_init_seq(skb, mss); 2105 } 2106 #else 2107 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2108 const struct sock *sk, struct sk_buff *skb, 2109 __u16 *mss) 2110 { 2111 return 0; 2112 } 2113 #endif 2114 2115 int tcpv4_offload_init(void); 2116 2117 void tcp_v4_init(void); 2118 void tcp_init(void); 2119 2120 /* tcp_recovery.c */ 2121 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2122 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2123 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2124 u32 reo_wnd); 2125 extern bool tcp_rack_mark_lost(struct sock *sk); 2126 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2127 u64 xmit_time); 2128 extern void tcp_rack_reo_timeout(struct sock *sk); 2129 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2130 2131 /* At how many usecs into the future should the RTO fire? */ 2132 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2133 { 2134 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2135 u32 rto = inet_csk(sk)->icsk_rto; 2136 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2137 2138 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2139 } 2140 2141 /* 2142 * Save and compile IPv4 options, return a pointer to it 2143 */ 2144 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2145 struct sk_buff *skb) 2146 { 2147 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2148 struct ip_options_rcu *dopt = NULL; 2149 2150 if (opt->optlen) { 2151 int opt_size = sizeof(*dopt) + opt->optlen; 2152 2153 dopt = kmalloc(opt_size, GFP_ATOMIC); 2154 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2155 kfree(dopt); 2156 dopt = NULL; 2157 } 2158 } 2159 return dopt; 2160 } 2161 2162 /* locally generated TCP pure ACKs have skb->truesize == 2 2163 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2164 * This is much faster than dissecting the packet to find out. 2165 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2166 */ 2167 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2168 { 2169 return skb->truesize == 2; 2170 } 2171 2172 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2173 { 2174 skb->truesize = 2; 2175 } 2176 2177 static inline int tcp_inq(struct sock *sk) 2178 { 2179 struct tcp_sock *tp = tcp_sk(sk); 2180 int answ; 2181 2182 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2183 answ = 0; 2184 } else if (sock_flag(sk, SOCK_URGINLINE) || 2185 !tp->urg_data || 2186 before(tp->urg_seq, tp->copied_seq) || 2187 !before(tp->urg_seq, tp->rcv_nxt)) { 2188 2189 answ = tp->rcv_nxt - tp->copied_seq; 2190 2191 /* Subtract 1, if FIN was received */ 2192 if (answ && sock_flag(sk, SOCK_DONE)) 2193 answ--; 2194 } else { 2195 answ = tp->urg_seq - tp->copied_seq; 2196 } 2197 2198 return answ; 2199 } 2200 2201 int tcp_peek_len(struct socket *sock); 2202 2203 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2204 { 2205 u16 segs_in; 2206 2207 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2208 2209 /* We update these fields while other threads might 2210 * read them from tcp_get_info() 2211 */ 2212 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2213 if (skb->len > tcp_hdrlen(skb)) 2214 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2215 } 2216 2217 /* 2218 * TCP listen path runs lockless. 2219 * We forced "struct sock" to be const qualified to make sure 2220 * we don't modify one of its field by mistake. 2221 * Here, we increment sk_drops which is an atomic_t, so we can safely 2222 * make sock writable again. 2223 */ 2224 static inline void tcp_listendrop(const struct sock *sk) 2225 { 2226 atomic_inc(&((struct sock *)sk)->sk_drops); 2227 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2228 } 2229 2230 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2231 2232 /* 2233 * Interface for adding Upper Level Protocols over TCP 2234 */ 2235 2236 #define TCP_ULP_NAME_MAX 16 2237 #define TCP_ULP_MAX 128 2238 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2239 2240 struct tcp_ulp_ops { 2241 struct list_head list; 2242 2243 /* initialize ulp */ 2244 int (*init)(struct sock *sk); 2245 /* update ulp */ 2246 void (*update)(struct sock *sk, struct proto *p, 2247 void (*write_space)(struct sock *sk)); 2248 /* cleanup ulp */ 2249 void (*release)(struct sock *sk); 2250 /* diagnostic */ 2251 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2252 size_t (*get_info_size)(const struct sock *sk); 2253 /* clone ulp */ 2254 void (*clone)(const struct request_sock *req, struct sock *newsk, 2255 const gfp_t priority); 2256 2257 char name[TCP_ULP_NAME_MAX]; 2258 struct module *owner; 2259 }; 2260 int tcp_register_ulp(struct tcp_ulp_ops *type); 2261 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2262 int tcp_set_ulp(struct sock *sk, const char *name); 2263 void tcp_get_available_ulp(char *buf, size_t len); 2264 void tcp_cleanup_ulp(struct sock *sk); 2265 void tcp_update_ulp(struct sock *sk, struct proto *p, 2266 void (*write_space)(struct sock *sk)); 2267 2268 #define MODULE_ALIAS_TCP_ULP(name) \ 2269 __MODULE_INFO(alias, alias_userspace, name); \ 2270 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2271 2272 #ifdef CONFIG_NET_SOCK_MSG 2273 struct sk_msg; 2274 struct sk_psock; 2275 2276 #ifdef CONFIG_BPF_SYSCALL 2277 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 2278 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2279 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2280 #endif /* CONFIG_BPF_SYSCALL */ 2281 2282 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes, 2283 int flags); 2284 #endif /* CONFIG_NET_SOCK_MSG */ 2285 2286 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2287 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2288 { 2289 } 2290 #endif 2291 2292 #ifdef CONFIG_CGROUP_BPF 2293 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2294 struct sk_buff *skb, 2295 unsigned int end_offset) 2296 { 2297 skops->skb = skb; 2298 skops->skb_data_end = skb->data + end_offset; 2299 } 2300 #else 2301 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2302 struct sk_buff *skb, 2303 unsigned int end_offset) 2304 { 2305 } 2306 #endif 2307 2308 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2309 * is < 0, then the BPF op failed (for example if the loaded BPF 2310 * program does not support the chosen operation or there is no BPF 2311 * program loaded). 2312 */ 2313 #ifdef CONFIG_BPF 2314 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2315 { 2316 struct bpf_sock_ops_kern sock_ops; 2317 int ret; 2318 2319 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2320 if (sk_fullsock(sk)) { 2321 sock_ops.is_fullsock = 1; 2322 sock_owned_by_me(sk); 2323 } 2324 2325 sock_ops.sk = sk; 2326 sock_ops.op = op; 2327 if (nargs > 0) 2328 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2329 2330 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2331 if (ret == 0) 2332 ret = sock_ops.reply; 2333 else 2334 ret = -1; 2335 return ret; 2336 } 2337 2338 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2339 { 2340 u32 args[2] = {arg1, arg2}; 2341 2342 return tcp_call_bpf(sk, op, 2, args); 2343 } 2344 2345 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2346 u32 arg3) 2347 { 2348 u32 args[3] = {arg1, arg2, arg3}; 2349 2350 return tcp_call_bpf(sk, op, 3, args); 2351 } 2352 2353 #else 2354 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2355 { 2356 return -EPERM; 2357 } 2358 2359 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2360 { 2361 return -EPERM; 2362 } 2363 2364 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2365 u32 arg3) 2366 { 2367 return -EPERM; 2368 } 2369 2370 #endif 2371 2372 static inline u32 tcp_timeout_init(struct sock *sk) 2373 { 2374 int timeout; 2375 2376 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2377 2378 if (timeout <= 0) 2379 timeout = TCP_TIMEOUT_INIT; 2380 return min_t(int, timeout, TCP_RTO_MAX); 2381 } 2382 2383 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2384 { 2385 int rwnd; 2386 2387 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2388 2389 if (rwnd < 0) 2390 rwnd = 0; 2391 return rwnd; 2392 } 2393 2394 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2395 { 2396 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2397 } 2398 2399 static inline void tcp_bpf_rtt(struct sock *sk) 2400 { 2401 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2402 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2403 } 2404 2405 #if IS_ENABLED(CONFIG_SMC) 2406 extern struct static_key_false tcp_have_smc; 2407 #endif 2408 2409 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2410 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2411 void (*cad)(struct sock *sk, u32 ack_seq)); 2412 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2413 void clean_acked_data_flush(void); 2414 #endif 2415 2416 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2417 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2418 const struct tcp_sock *tp) 2419 { 2420 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2421 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2422 } 2423 2424 /* Compute Earliest Departure Time for some control packets 2425 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2426 */ 2427 static inline u64 tcp_transmit_time(const struct sock *sk) 2428 { 2429 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2430 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2431 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2432 2433 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2434 } 2435 return 0; 2436 } 2437 2438 #endif /* _TCP_H */ 2439