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_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 DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); 255 256 extern struct percpu_counter tcp_sockets_allocated; 257 extern unsigned long tcp_memory_pressure; 258 259 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 260 static inline bool tcp_under_memory_pressure(const struct sock *sk) 261 { 262 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 263 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 264 return true; 265 266 return READ_ONCE(tcp_memory_pressure); 267 } 268 /* 269 * The next routines deal with comparing 32 bit unsigned ints 270 * and worry about wraparound (automatic with unsigned arithmetic). 271 */ 272 273 static inline bool before(__u32 seq1, __u32 seq2) 274 { 275 return (__s32)(seq1-seq2) < 0; 276 } 277 #define after(seq2, seq1) before(seq1, seq2) 278 279 /* is s2<=s1<=s3 ? */ 280 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 281 { 282 return seq3 - seq2 >= seq1 - seq2; 283 } 284 285 static inline bool tcp_out_of_memory(struct sock *sk) 286 { 287 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 288 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 289 return true; 290 return false; 291 } 292 293 static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb) 294 { 295 sk_wmem_queued_add(sk, -skb->truesize); 296 if (!skb_zcopy_pure(skb)) 297 sk_mem_uncharge(sk, skb->truesize); 298 else 299 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb))); 300 __kfree_skb(skb); 301 } 302 303 void sk_forced_mem_schedule(struct sock *sk, int size); 304 305 bool tcp_check_oom(struct sock *sk, int shift); 306 307 308 extern struct proto tcp_prot; 309 310 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 311 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 312 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 313 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 314 315 void tcp_tasklet_init(void); 316 317 int tcp_v4_err(struct sk_buff *skb, u32); 318 319 void tcp_shutdown(struct sock *sk, int how); 320 321 int tcp_v4_early_demux(struct sk_buff *skb); 322 int tcp_v4_rcv(struct sk_buff *skb); 323 324 void tcp_remove_empty_skb(struct sock *sk); 325 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 326 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 327 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); 328 int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, 329 size_t size, struct ubuf_info *uarg); 330 void tcp_splice_eof(struct socket *sock); 331 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, 332 int flags); 333 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, 334 size_t size, int flags); 335 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 336 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 337 int size_goal); 338 void tcp_release_cb(struct sock *sk); 339 void tcp_wfree(struct sk_buff *skb); 340 void tcp_write_timer_handler(struct sock *sk); 341 void tcp_delack_timer_handler(struct sock *sk); 342 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); 343 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 344 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 345 void tcp_rcv_space_adjust(struct sock *sk); 346 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 347 void tcp_twsk_destructor(struct sock *sk); 348 void tcp_twsk_purge(struct list_head *net_exit_list, int family); 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 do_tcp_getsockopt(struct sock *sk, int level, 406 int optname, sockptr_t optval, sockptr_t optlen); 407 int tcp_getsockopt(struct sock *sk, int level, int optname, 408 char __user *optval, int __user *optlen); 409 bool tcp_bpf_bypass_getsockopt(int level, int optname); 410 int do_tcp_setsockopt(struct sock *sk, int level, int optname, 411 sockptr_t optval, unsigned int optlen); 412 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 413 unsigned int optlen); 414 void tcp_set_keepalive(struct sock *sk, int val); 415 void tcp_syn_ack_timeout(const struct request_sock *req); 416 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 417 int flags, int *addr_len); 418 int tcp_set_rcvlowat(struct sock *sk, int val); 419 int tcp_set_window_clamp(struct sock *sk, int val); 420 void tcp_update_recv_tstamps(struct sk_buff *skb, 421 struct scm_timestamping_internal *tss); 422 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk, 423 struct scm_timestamping_internal *tss); 424 void tcp_data_ready(struct sock *sk); 425 #ifdef CONFIG_MMU 426 int tcp_mmap(struct file *file, struct socket *sock, 427 struct vm_area_struct *vma); 428 #endif 429 void tcp_parse_options(const struct net *net, const struct sk_buff *skb, 430 struct tcp_options_received *opt_rx, 431 int estab, struct tcp_fastopen_cookie *foc); 432 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); 433 434 /* 435 * BPF SKB-less helpers 436 */ 437 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 438 struct tcphdr *th, u32 *cookie); 439 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 440 struct tcphdr *th, u32 *cookie); 441 u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss); 442 u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, 443 const struct tcp_request_sock_ops *af_ops, 444 struct sock *sk, struct tcphdr *th); 445 /* 446 * TCP v4 functions exported for the inet6 API 447 */ 448 449 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); 450 void tcp_v4_mtu_reduced(struct sock *sk); 451 void tcp_req_err(struct sock *sk, u32 seq, bool abort); 452 void tcp_ld_RTO_revert(struct sock *sk, u32 seq); 453 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 454 struct sock *tcp_create_openreq_child(const struct sock *sk, 455 struct request_sock *req, 456 struct sk_buff *skb); 457 void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst); 458 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 459 struct request_sock *req, 460 struct dst_entry *dst, 461 struct request_sock *req_unhash, 462 bool *own_req); 463 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 464 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 465 int tcp_connect(struct sock *sk); 466 enum tcp_synack_type { 467 TCP_SYNACK_NORMAL, 468 TCP_SYNACK_FASTOPEN, 469 TCP_SYNACK_COOKIE, 470 }; 471 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 472 struct request_sock *req, 473 struct tcp_fastopen_cookie *foc, 474 enum tcp_synack_type synack_type, 475 struct sk_buff *syn_skb); 476 int tcp_disconnect(struct sock *sk, int flags); 477 478 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb); 479 int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); 480 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); 481 482 /* From syncookies.c */ 483 struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, 484 struct request_sock *req, 485 struct dst_entry *dst, u32 tsoff); 486 int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, 487 u32 cookie); 488 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); 489 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops, 490 const struct tcp_request_sock_ops *af_ops, 491 struct sock *sk, struct sk_buff *skb); 492 #ifdef CONFIG_SYN_COOKIES 493 494 /* Syncookies use a monotonic timer which increments every 60 seconds. 495 * This counter is used both as a hash input and partially encoded into 496 * the cookie value. A cookie is only validated further if the delta 497 * between the current counter value and the encoded one is less than this, 498 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if 499 * the counter advances immediately after a cookie is generated). 500 */ 501 #define MAX_SYNCOOKIE_AGE 2 502 #define TCP_SYNCOOKIE_PERIOD (60 * HZ) 503 #define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD) 504 505 /* syncookies: remember time of last synqueue overflow 506 * But do not dirty this field too often (once per second is enough) 507 * It is racy as we do not hold a lock, but race is very minor. 508 */ 509 static inline void tcp_synq_overflow(const struct sock *sk) 510 { 511 unsigned int last_overflow; 512 unsigned int now = jiffies; 513 514 if (sk->sk_reuseport) { 515 struct sock_reuseport *reuse; 516 517 reuse = rcu_dereference(sk->sk_reuseport_cb); 518 if (likely(reuse)) { 519 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 520 if (!time_between32(now, last_overflow, 521 last_overflow + HZ)) 522 WRITE_ONCE(reuse->synq_overflow_ts, now); 523 return; 524 } 525 } 526 527 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 528 if (!time_between32(now, last_overflow, last_overflow + HZ)) 529 WRITE_ONCE(tcp_sk_rw(sk)->rx_opt.ts_recent_stamp, now); 530 } 531 532 /* syncookies: no recent synqueue overflow on this listening socket? */ 533 static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) 534 { 535 unsigned int last_overflow; 536 unsigned int now = jiffies; 537 538 if (sk->sk_reuseport) { 539 struct sock_reuseport *reuse; 540 541 reuse = rcu_dereference(sk->sk_reuseport_cb); 542 if (likely(reuse)) { 543 last_overflow = READ_ONCE(reuse->synq_overflow_ts); 544 return !time_between32(now, last_overflow - HZ, 545 last_overflow + 546 TCP_SYNCOOKIE_VALID); 547 } 548 } 549 550 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); 551 552 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, 553 * then we're under synflood. However, we have to use 554 * 'last_overflow - HZ' as lower bound. That's because a concurrent 555 * tcp_synq_overflow() could update .ts_recent_stamp after we read 556 * jiffies but before we store .ts_recent_stamp into last_overflow, 557 * which could lead to rejecting a valid syncookie. 558 */ 559 return !time_between32(now, last_overflow - HZ, 560 last_overflow + TCP_SYNCOOKIE_VALID); 561 } 562 563 static inline u32 tcp_cookie_time(void) 564 { 565 u64 val = get_jiffies_64(); 566 567 do_div(val, TCP_SYNCOOKIE_PERIOD); 568 return val; 569 } 570 571 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, 572 u16 *mssp); 573 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); 574 u64 cookie_init_timestamp(struct request_sock *req, u64 now); 575 bool cookie_timestamp_decode(const struct net *net, 576 struct tcp_options_received *opt); 577 bool cookie_ecn_ok(const struct tcp_options_received *opt, 578 const struct net *net, const struct dst_entry *dst); 579 580 /* From net/ipv6/syncookies.c */ 581 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, 582 u32 cookie); 583 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 584 585 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, 586 const struct tcphdr *th, u16 *mssp); 587 __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); 588 #endif 589 /* tcp_output.c */ 590 591 void tcp_skb_entail(struct sock *sk, struct sk_buff *skb); 592 void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb); 593 void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 594 int nonagle); 595 int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 596 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs); 597 void tcp_retransmit_timer(struct sock *sk); 598 void tcp_xmit_retransmit_queue(struct sock *); 599 void tcp_simple_retransmit(struct sock *); 600 void tcp_enter_recovery(struct sock *sk, bool ece_ack); 601 int tcp_trim_head(struct sock *, struct sk_buff *, u32); 602 enum tcp_queue { 603 TCP_FRAG_IN_WRITE_QUEUE, 604 TCP_FRAG_IN_RTX_QUEUE, 605 }; 606 int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue, 607 struct sk_buff *skb, u32 len, 608 unsigned int mss_now, gfp_t gfp); 609 610 void tcp_send_probe0(struct sock *); 611 void tcp_send_partial(struct sock *); 612 int tcp_write_wakeup(struct sock *, int mib); 613 void tcp_send_fin(struct sock *sk); 614 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 615 int tcp_send_synack(struct sock *); 616 void tcp_push_one(struct sock *, unsigned int mss_now); 617 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 618 void tcp_send_ack(struct sock *sk); 619 void tcp_send_delayed_ack(struct sock *sk); 620 void tcp_send_loss_probe(struct sock *sk); 621 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 622 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 623 const struct sk_buff *next_skb); 624 625 /* tcp_input.c */ 626 void tcp_rearm_rto(struct sock *sk); 627 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 628 void tcp_reset(struct sock *sk, struct sk_buff *skb); 629 void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb); 630 void tcp_fin(struct sock *sk); 631 void tcp_check_space(struct sock *sk); 632 void tcp_sack_compress_send_ack(struct sock *sk); 633 634 /* tcp_timer.c */ 635 void tcp_init_xmit_timers(struct sock *); 636 static inline void tcp_clear_xmit_timers(struct sock *sk) 637 { 638 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 639 __sock_put(sk); 640 641 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 642 __sock_put(sk); 643 644 inet_csk_clear_xmit_timers(sk); 645 } 646 647 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 648 unsigned int tcp_current_mss(struct sock *sk); 649 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 650 651 /* Bound MSS / TSO packet size with the half of the window */ 652 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 653 { 654 int cutoff; 655 656 /* When peer uses tiny windows, there is no use in packetizing 657 * to sub-MSS pieces for the sake of SWS or making sure there 658 * are enough packets in the pipe for fast recovery. 659 * 660 * On the other hand, for extremely large MSS devices, handling 661 * smaller than MSS windows in this way does make sense. 662 */ 663 if (tp->max_window > TCP_MSS_DEFAULT) 664 cutoff = (tp->max_window >> 1); 665 else 666 cutoff = tp->max_window; 667 668 if (cutoff && pktsize > cutoff) 669 return max_t(int, cutoff, 68U - tp->tcp_header_len); 670 else 671 return pktsize; 672 } 673 674 /* tcp.c */ 675 void tcp_get_info(struct sock *, struct tcp_info *); 676 677 /* Read 'sendfile()'-style from a TCP socket */ 678 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 679 sk_read_actor_t recv_actor); 680 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 681 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off); 682 void tcp_read_done(struct sock *sk, size_t len); 683 684 void tcp_initialize_rcv_mss(struct sock *sk); 685 686 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 687 int tcp_mss_to_mtu(struct sock *sk, int mss); 688 void tcp_mtup_init(struct sock *sk); 689 690 static inline void tcp_bound_rto(const struct sock *sk) 691 { 692 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 693 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 694 } 695 696 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 697 { 698 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 699 } 700 701 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 702 { 703 /* mptcp hooks are only on the slow path */ 704 if (sk_is_mptcp((struct sock *)tp)) 705 return; 706 707 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 708 ntohl(TCP_FLAG_ACK) | 709 snd_wnd); 710 } 711 712 static inline void tcp_fast_path_on(struct tcp_sock *tp) 713 { 714 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 715 } 716 717 static inline void tcp_fast_path_check(struct sock *sk) 718 { 719 struct tcp_sock *tp = tcp_sk(sk); 720 721 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 722 tp->rcv_wnd && 723 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 724 !tp->urg_data) 725 tcp_fast_path_on(tp); 726 } 727 728 /* Compute the actual rto_min value */ 729 static inline u32 tcp_rto_min(struct sock *sk) 730 { 731 const struct dst_entry *dst = __sk_dst_get(sk); 732 u32 rto_min = inet_csk(sk)->icsk_rto_min; 733 734 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 735 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 736 return rto_min; 737 } 738 739 static inline u32 tcp_rto_min_us(struct sock *sk) 740 { 741 return jiffies_to_usecs(tcp_rto_min(sk)); 742 } 743 744 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 745 { 746 return dst_metric_locked(dst, RTAX_CC_ALGO); 747 } 748 749 /* Minimum RTT in usec. ~0 means not available. */ 750 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 751 { 752 return minmax_get(&tp->rtt_min); 753 } 754 755 /* Compute the actual receive window we are currently advertising. 756 * Rcv_nxt can be after the window if our peer push more data 757 * than the offered window. 758 */ 759 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 760 { 761 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 762 763 if (win < 0) 764 win = 0; 765 return (u32) win; 766 } 767 768 /* Choose a new window, without checks for shrinking, and without 769 * scaling applied to the result. The caller does these things 770 * if necessary. This is a "raw" window selection. 771 */ 772 u32 __tcp_select_window(struct sock *sk); 773 774 void tcp_send_window_probe(struct sock *sk); 775 776 /* TCP uses 32bit jiffies to save some space. 777 * Note that this is different from tcp_time_stamp, which 778 * historically has been the same until linux-4.13. 779 */ 780 #define tcp_jiffies32 ((u32)jiffies) 781 782 /* 783 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 784 * It is no longer tied to jiffies, but to 1 ms clock. 785 * Note: double check if you want to use tcp_jiffies32 instead of this. 786 */ 787 #define TCP_TS_HZ 1000 788 789 static inline u64 tcp_clock_ns(void) 790 { 791 return ktime_get_ns(); 792 } 793 794 static inline u64 tcp_clock_us(void) 795 { 796 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 797 } 798 799 /* This should only be used in contexts where tp->tcp_mstamp is up to date */ 800 static inline u32 tcp_time_stamp(const struct tcp_sock *tp) 801 { 802 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); 803 } 804 805 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ 806 static inline u32 tcp_ns_to_ts(u64 ns) 807 { 808 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); 809 } 810 811 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ 812 static inline u32 tcp_time_stamp_raw(void) 813 { 814 return tcp_ns_to_ts(tcp_clock_ns()); 815 } 816 817 void tcp_mstamp_refresh(struct tcp_sock *tp); 818 819 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 820 { 821 return max_t(s64, t1 - t0, 0); 822 } 823 824 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 825 { 826 return tcp_ns_to_ts(skb->skb_mstamp_ns); 827 } 828 829 /* provide the departure time in us unit */ 830 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 831 { 832 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 833 } 834 835 836 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 837 838 #define TCPHDR_FIN 0x01 839 #define TCPHDR_SYN 0x02 840 #define TCPHDR_RST 0x04 841 #define TCPHDR_PSH 0x08 842 #define TCPHDR_ACK 0x10 843 #define TCPHDR_URG 0x20 844 #define TCPHDR_ECE 0x40 845 #define TCPHDR_CWR 0x80 846 847 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 848 849 /* This is what the send packet queuing engine uses to pass 850 * TCP per-packet control information to the transmission code. 851 * We also store the host-order sequence numbers in here too. 852 * This is 44 bytes if IPV6 is enabled. 853 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 854 */ 855 struct tcp_skb_cb { 856 __u32 seq; /* Starting sequence number */ 857 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 858 union { 859 /* Note : tcp_tw_isn is used in input path only 860 * (isn chosen by tcp_timewait_state_process()) 861 * 862 * tcp_gso_segs/size are used in write queue only, 863 * cf tcp_skb_pcount()/tcp_skb_mss() 864 */ 865 __u32 tcp_tw_isn; 866 struct { 867 u16 tcp_gso_segs; 868 u16 tcp_gso_size; 869 }; 870 }; 871 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 872 873 __u8 sacked; /* State flags for SACK. */ 874 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 875 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 876 #define TCPCB_LOST 0x04 /* SKB is lost */ 877 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 878 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 879 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 880 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 881 TCPCB_REPAIRED) 882 883 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 884 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 885 eor:1, /* Is skb MSG_EOR marked? */ 886 has_rxtstamp:1, /* SKB has a RX timestamp */ 887 unused:5; 888 __u32 ack_seq; /* Sequence number ACK'd */ 889 union { 890 struct { 891 #define TCPCB_DELIVERED_CE_MASK ((1U<<20) - 1) 892 /* There is space for up to 24 bytes */ 893 __u32 is_app_limited:1, /* cwnd not fully used? */ 894 delivered_ce:20, 895 unused:11; 896 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 897 __u32 delivered; 898 /* start of send pipeline phase */ 899 u64 first_tx_mstamp; 900 /* when we reached the "delivered" count */ 901 u64 delivered_mstamp; 902 } tx; /* only used for outgoing skbs */ 903 union { 904 struct inet_skb_parm h4; 905 #if IS_ENABLED(CONFIG_IPV6) 906 struct inet6_skb_parm h6; 907 #endif 908 } header; /* For incoming skbs */ 909 }; 910 }; 911 912 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 913 914 extern const struct inet_connection_sock_af_ops ipv4_specific; 915 916 #if IS_ENABLED(CONFIG_IPV6) 917 /* This is the variant of inet6_iif() that must be used by TCP, 918 * as TCP moves IP6CB into a different location in skb->cb[] 919 */ 920 static inline int tcp_v6_iif(const struct sk_buff *skb) 921 { 922 return TCP_SKB_CB(skb)->header.h6.iif; 923 } 924 925 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 926 { 927 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 928 929 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 930 } 931 932 /* TCP_SKB_CB reference means this can not be used from early demux */ 933 static inline int tcp_v6_sdif(const struct sk_buff *skb) 934 { 935 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 936 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 937 return TCP_SKB_CB(skb)->header.h6.iif; 938 #endif 939 return 0; 940 } 941 942 extern const struct inet_connection_sock_af_ops ipv6_specific; 943 944 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 945 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 946 void tcp_v6_early_demux(struct sk_buff *skb); 947 948 #endif 949 950 /* TCP_SKB_CB reference means this can not be used from early demux */ 951 static inline int tcp_v4_sdif(struct sk_buff *skb) 952 { 953 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 954 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 955 return TCP_SKB_CB(skb)->header.h4.iif; 956 #endif 957 return 0; 958 } 959 960 /* Due to TSO, an SKB can be composed of multiple actual 961 * packets. To keep these tracked properly, we use this. 962 */ 963 static inline int tcp_skb_pcount(const struct sk_buff *skb) 964 { 965 return TCP_SKB_CB(skb)->tcp_gso_segs; 966 } 967 968 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 969 { 970 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 971 } 972 973 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 974 { 975 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 976 } 977 978 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 979 static inline int tcp_skb_mss(const struct sk_buff *skb) 980 { 981 return TCP_SKB_CB(skb)->tcp_gso_size; 982 } 983 984 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 985 { 986 return likely(!TCP_SKB_CB(skb)->eor); 987 } 988 989 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 990 const struct sk_buff *from) 991 { 992 return likely(tcp_skb_can_collapse_to(to) && 993 mptcp_skb_can_collapse(to, from) && 994 skb_pure_zcopy_same(to, from)); 995 } 996 997 /* Events passed to congestion control interface */ 998 enum tcp_ca_event { 999 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 1000 CA_EVENT_CWND_RESTART, /* congestion window restart */ 1001 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 1002 CA_EVENT_LOSS, /* loss timeout */ 1003 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 1004 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 1005 }; 1006 1007 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1008 enum tcp_ca_ack_event_flags { 1009 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1010 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1011 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1012 }; 1013 1014 /* 1015 * Interface for adding new TCP congestion control handlers 1016 */ 1017 #define TCP_CA_NAME_MAX 16 1018 #define TCP_CA_MAX 128 1019 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1020 1021 #define TCP_CA_UNSPEC 0 1022 1023 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1024 #define TCP_CONG_NON_RESTRICTED 0x1 1025 /* Requires ECN/ECT set on all packets */ 1026 #define TCP_CONG_NEEDS_ECN 0x2 1027 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1028 1029 union tcp_cc_info; 1030 1031 struct ack_sample { 1032 u32 pkts_acked; 1033 s32 rtt_us; 1034 u32 in_flight; 1035 }; 1036 1037 /* A rate sample measures the number of (original/retransmitted) data 1038 * packets delivered "delivered" over an interval of time "interval_us". 1039 * The tcp_rate.c code fills in the rate sample, and congestion 1040 * control modules that define a cong_control function to run at the end 1041 * of ACK processing can optionally chose to consult this sample when 1042 * setting cwnd and pacing rate. 1043 * A sample is invalid if "delivered" or "interval_us" is negative. 1044 */ 1045 struct rate_sample { 1046 u64 prior_mstamp; /* starting timestamp for interval */ 1047 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1048 u32 prior_delivered_ce;/* tp->delivered_ce at "prior_mstamp" */ 1049 s32 delivered; /* number of packets delivered over interval */ 1050 s32 delivered_ce; /* number of packets delivered w/ CE marks*/ 1051 long interval_us; /* time for tp->delivered to incr "delivered" */ 1052 u32 snd_interval_us; /* snd interval for delivered packets */ 1053 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1054 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1055 int losses; /* number of packets marked lost upon ACK */ 1056 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1057 u32 prior_in_flight; /* in flight before this ACK */ 1058 u32 last_end_seq; /* end_seq of most recently ACKed packet */ 1059 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1060 bool is_retrans; /* is sample from retransmission? */ 1061 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1062 }; 1063 1064 struct tcp_congestion_ops { 1065 /* fast path fields are put first to fill one cache line */ 1066 1067 /* return slow start threshold (required) */ 1068 u32 (*ssthresh)(struct sock *sk); 1069 1070 /* do new cwnd calculation (required) */ 1071 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1072 1073 /* call before changing ca_state (optional) */ 1074 void (*set_state)(struct sock *sk, u8 new_state); 1075 1076 /* call when cwnd event occurs (optional) */ 1077 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1078 1079 /* call when ack arrives (optional) */ 1080 void (*in_ack_event)(struct sock *sk, u32 flags); 1081 1082 /* hook for packet ack accounting (optional) */ 1083 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1084 1085 /* override sysctl_tcp_min_tso_segs */ 1086 u32 (*min_tso_segs)(struct sock *sk); 1087 1088 /* call when packets are delivered to update cwnd and pacing rate, 1089 * after all the ca_state processing. (optional) 1090 */ 1091 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1092 1093 1094 /* new value of cwnd after loss (required) */ 1095 u32 (*undo_cwnd)(struct sock *sk); 1096 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1097 u32 (*sndbuf_expand)(struct sock *sk); 1098 1099 /* control/slow paths put last */ 1100 /* get info for inet_diag (optional) */ 1101 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1102 union tcp_cc_info *info); 1103 1104 char name[TCP_CA_NAME_MAX]; 1105 struct module *owner; 1106 struct list_head list; 1107 u32 key; 1108 u32 flags; 1109 1110 /* initialize private data (optional) */ 1111 void (*init)(struct sock *sk); 1112 /* cleanup private data (optional) */ 1113 void (*release)(struct sock *sk); 1114 } ____cacheline_aligned_in_smp; 1115 1116 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1117 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1118 int tcp_update_congestion_control(struct tcp_congestion_ops *type, 1119 struct tcp_congestion_ops *old_type); 1120 int tcp_validate_congestion_control(struct tcp_congestion_ops *ca); 1121 1122 void tcp_assign_congestion_control(struct sock *sk); 1123 void tcp_init_congestion_control(struct sock *sk); 1124 void tcp_cleanup_congestion_control(struct sock *sk); 1125 int tcp_set_default_congestion_control(struct net *net, const char *name); 1126 void tcp_get_default_congestion_control(struct net *net, char *name); 1127 void tcp_get_available_congestion_control(char *buf, size_t len); 1128 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1129 int tcp_set_allowed_congestion_control(char *allowed); 1130 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1131 bool cap_net_admin); 1132 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1133 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1134 1135 u32 tcp_reno_ssthresh(struct sock *sk); 1136 u32 tcp_reno_undo_cwnd(struct sock *sk); 1137 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1138 extern struct tcp_congestion_ops tcp_reno; 1139 1140 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1141 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1142 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1143 #ifdef CONFIG_INET 1144 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1145 #else 1146 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1147 { 1148 return NULL; 1149 } 1150 #endif 1151 1152 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1153 { 1154 const struct inet_connection_sock *icsk = inet_csk(sk); 1155 1156 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1157 } 1158 1159 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1160 { 1161 const struct inet_connection_sock *icsk = inet_csk(sk); 1162 1163 if (icsk->icsk_ca_ops->cwnd_event) 1164 icsk->icsk_ca_ops->cwnd_event(sk, event); 1165 } 1166 1167 /* From tcp_cong.c */ 1168 void tcp_set_ca_state(struct sock *sk, const u8 ca_state); 1169 1170 /* From tcp_rate.c */ 1171 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1172 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1173 struct rate_sample *rs); 1174 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1175 bool is_sack_reneg, struct rate_sample *rs); 1176 void tcp_rate_check_app_limited(struct sock *sk); 1177 1178 static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2) 1179 { 1180 return t1 > t2 || (t1 == t2 && after(seq1, seq2)); 1181 } 1182 1183 /* These functions determine how the current flow behaves in respect of SACK 1184 * handling. SACK is negotiated with the peer, and therefore it can vary 1185 * between different flows. 1186 * 1187 * tcp_is_sack - SACK enabled 1188 * tcp_is_reno - No SACK 1189 */ 1190 static inline int tcp_is_sack(const struct tcp_sock *tp) 1191 { 1192 return likely(tp->rx_opt.sack_ok); 1193 } 1194 1195 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1196 { 1197 return !tcp_is_sack(tp); 1198 } 1199 1200 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1201 { 1202 return tp->sacked_out + tp->lost_out; 1203 } 1204 1205 /* This determines how many packets are "in the network" to the best 1206 * of our knowledge. In many cases it is conservative, but where 1207 * detailed information is available from the receiver (via SACK 1208 * blocks etc.) we can make more aggressive calculations. 1209 * 1210 * Use this for decisions involving congestion control, use just 1211 * tp->packets_out to determine if the send queue is empty or not. 1212 * 1213 * Read this equation as: 1214 * 1215 * "Packets sent once on transmission queue" MINUS 1216 * "Packets left network, but not honestly ACKed yet" PLUS 1217 * "Packets fast retransmitted" 1218 */ 1219 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1220 { 1221 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1222 } 1223 1224 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1225 1226 static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp) 1227 { 1228 return tp->snd_cwnd; 1229 } 1230 1231 static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val) 1232 { 1233 WARN_ON_ONCE((int)val <= 0); 1234 tp->snd_cwnd = val; 1235 } 1236 1237 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1238 { 1239 return tcp_snd_cwnd(tp) < tp->snd_ssthresh; 1240 } 1241 1242 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1243 { 1244 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1245 } 1246 1247 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1248 { 1249 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1250 (1 << inet_csk(sk)->icsk_ca_state); 1251 } 1252 1253 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1254 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1255 * ssthresh. 1256 */ 1257 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1258 { 1259 const struct tcp_sock *tp = tcp_sk(sk); 1260 1261 if (tcp_in_cwnd_reduction(sk)) 1262 return tp->snd_ssthresh; 1263 else 1264 return max(tp->snd_ssthresh, 1265 ((tcp_snd_cwnd(tp) >> 1) + 1266 (tcp_snd_cwnd(tp) >> 2))); 1267 } 1268 1269 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1270 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1271 1272 void tcp_enter_cwr(struct sock *sk); 1273 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1274 1275 /* The maximum number of MSS of available cwnd for which TSO defers 1276 * sending if not using sysctl_tcp_tso_win_divisor. 1277 */ 1278 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1279 { 1280 return 3; 1281 } 1282 1283 /* Returns end sequence number of the receiver's advertised window */ 1284 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1285 { 1286 return tp->snd_una + tp->snd_wnd; 1287 } 1288 1289 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1290 * flexible approach. The RFC suggests cwnd should not be raised unless 1291 * it was fully used previously. And that's exactly what we do in 1292 * congestion avoidance mode. But in slow start we allow cwnd to grow 1293 * as long as the application has used half the cwnd. 1294 * Example : 1295 * cwnd is 10 (IW10), but application sends 9 frames. 1296 * We allow cwnd to reach 18 when all frames are ACKed. 1297 * This check is safe because it's as aggressive as slow start which already 1298 * risks 100% overshoot. The advantage is that we discourage application to 1299 * either send more filler packets or data to artificially blow up the cwnd 1300 * usage, and allow application-limited process to probe bw more aggressively. 1301 */ 1302 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1303 { 1304 const struct tcp_sock *tp = tcp_sk(sk); 1305 1306 if (tp->is_cwnd_limited) 1307 return true; 1308 1309 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1310 if (tcp_in_slow_start(tp)) 1311 return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out; 1312 1313 return false; 1314 } 1315 1316 /* BBR congestion control needs pacing. 1317 * Same remark for SO_MAX_PACING_RATE. 1318 * sch_fq packet scheduler is efficiently handling pacing, 1319 * but is not always installed/used. 1320 * Return true if TCP stack should pace packets itself. 1321 */ 1322 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1323 { 1324 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1325 } 1326 1327 /* Estimates in how many jiffies next packet for this flow can be sent. 1328 * Scheduling a retransmit timer too early would be silly. 1329 */ 1330 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1331 { 1332 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1333 1334 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1335 } 1336 1337 static inline void tcp_reset_xmit_timer(struct sock *sk, 1338 const int what, 1339 unsigned long when, 1340 const unsigned long max_when) 1341 { 1342 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk), 1343 max_when); 1344 } 1345 1346 /* Something is really bad, we could not queue an additional packet, 1347 * because qdisc is full or receiver sent a 0 window, or we are paced. 1348 * We do not want to add fuel to the fire, or abort too early, 1349 * so make sure the timer we arm now is at least 200ms in the future, 1350 * regardless of current icsk_rto value (as it could be ~2ms) 1351 */ 1352 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1353 { 1354 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1355 } 1356 1357 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1358 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1359 unsigned long max_when) 1360 { 1361 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1362 inet_csk(sk)->icsk_backoff); 1363 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1364 1365 return (unsigned long)min_t(u64, when, max_when); 1366 } 1367 1368 static inline void tcp_check_probe_timer(struct sock *sk) 1369 { 1370 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1371 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1372 tcp_probe0_base(sk), TCP_RTO_MAX); 1373 } 1374 1375 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1376 { 1377 tp->snd_wl1 = seq; 1378 } 1379 1380 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1381 { 1382 tp->snd_wl1 = seq; 1383 } 1384 1385 /* 1386 * Calculate(/check) TCP checksum 1387 */ 1388 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1389 __be32 daddr, __wsum base) 1390 { 1391 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1392 } 1393 1394 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1395 { 1396 return !skb_csum_unnecessary(skb) && 1397 __skb_checksum_complete(skb); 1398 } 1399 1400 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1401 enum skb_drop_reason *reason); 1402 1403 1404 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1405 void tcp_set_state(struct sock *sk, int state); 1406 void tcp_done(struct sock *sk); 1407 int tcp_abort(struct sock *sk, int err); 1408 1409 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1410 { 1411 rx_opt->dsack = 0; 1412 rx_opt->num_sacks = 0; 1413 } 1414 1415 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1416 1417 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1418 { 1419 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1420 struct tcp_sock *tp = tcp_sk(sk); 1421 s32 delta; 1422 1423 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) || 1424 tp->packets_out || ca_ops->cong_control) 1425 return; 1426 delta = tcp_jiffies32 - tp->lsndtime; 1427 if (delta > inet_csk(sk)->icsk_rto) 1428 tcp_cwnd_restart(sk, delta); 1429 } 1430 1431 /* Determine a window scaling and initial window to offer. */ 1432 void tcp_select_initial_window(const struct sock *sk, int __space, 1433 __u32 mss, __u32 *rcv_wnd, 1434 __u32 *window_clamp, int wscale_ok, 1435 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1436 1437 static inline int tcp_win_from_space(const struct sock *sk, int space) 1438 { 1439 int tcp_adv_win_scale = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale); 1440 1441 return tcp_adv_win_scale <= 0 ? 1442 (space>>(-tcp_adv_win_scale)) : 1443 space - (space>>tcp_adv_win_scale); 1444 } 1445 1446 /* Note: caller must be prepared to deal with negative returns */ 1447 static inline int tcp_space(const struct sock *sk) 1448 { 1449 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1450 READ_ONCE(sk->sk_backlog.len) - 1451 atomic_read(&sk->sk_rmem_alloc)); 1452 } 1453 1454 static inline int tcp_full_space(const struct sock *sk) 1455 { 1456 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1457 } 1458 1459 static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) 1460 { 1461 int unused_mem = sk_unused_reserved_mem(sk); 1462 struct tcp_sock *tp = tcp_sk(sk); 1463 1464 tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss); 1465 if (unused_mem) 1466 tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh, 1467 tcp_win_from_space(sk, unused_mem)); 1468 } 1469 1470 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1471 void __tcp_cleanup_rbuf(struct sock *sk, int copied); 1472 1473 1474 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1475 * If 87.5 % (7/8) of the space has been consumed, we want to override 1476 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1477 * len/truesize ratio. 1478 */ 1479 static inline bool tcp_rmem_pressure(const struct sock *sk) 1480 { 1481 int rcvbuf, threshold; 1482 1483 if (tcp_under_memory_pressure(sk)) 1484 return true; 1485 1486 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1487 threshold = rcvbuf - (rcvbuf >> 3); 1488 1489 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1490 } 1491 1492 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1493 { 1494 const struct tcp_sock *tp = tcp_sk(sk); 1495 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1496 1497 if (avail <= 0) 1498 return false; 1499 1500 return (avail >= target) || tcp_rmem_pressure(sk) || 1501 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1502 } 1503 1504 extern void tcp_openreq_init_rwin(struct request_sock *req, 1505 const struct sock *sk_listener, 1506 const struct dst_entry *dst); 1507 1508 void tcp_enter_memory_pressure(struct sock *sk); 1509 void tcp_leave_memory_pressure(struct sock *sk); 1510 1511 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1512 { 1513 struct net *net = sock_net((struct sock *)tp); 1514 1515 return tp->keepalive_intvl ? : 1516 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); 1517 } 1518 1519 static inline int keepalive_time_when(const struct tcp_sock *tp) 1520 { 1521 struct net *net = sock_net((struct sock *)tp); 1522 1523 return tp->keepalive_time ? : 1524 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); 1525 } 1526 1527 static inline int keepalive_probes(const struct tcp_sock *tp) 1528 { 1529 struct net *net = sock_net((struct sock *)tp); 1530 1531 return tp->keepalive_probes ? : 1532 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); 1533 } 1534 1535 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1536 { 1537 const struct inet_connection_sock *icsk = &tp->inet_conn; 1538 1539 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1540 tcp_jiffies32 - tp->rcv_tstamp); 1541 } 1542 1543 static inline int tcp_fin_time(const struct sock *sk) 1544 { 1545 int fin_timeout = tcp_sk(sk)->linger2 ? : 1546 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); 1547 const int rto = inet_csk(sk)->icsk_rto; 1548 1549 if (fin_timeout < (rto << 2) - (rto >> 1)) 1550 fin_timeout = (rto << 2) - (rto >> 1); 1551 1552 return fin_timeout; 1553 } 1554 1555 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1556 int paws_win) 1557 { 1558 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1559 return true; 1560 if (unlikely(!time_before32(ktime_get_seconds(), 1561 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1562 return true; 1563 /* 1564 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1565 * then following tcp messages have valid values. Ignore 0 value, 1566 * or else 'negative' tsval might forbid us to accept their packets. 1567 */ 1568 if (!rx_opt->ts_recent) 1569 return true; 1570 return false; 1571 } 1572 1573 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1574 int rst) 1575 { 1576 if (tcp_paws_check(rx_opt, 0)) 1577 return false; 1578 1579 /* RST segments are not recommended to carry timestamp, 1580 and, if they do, it is recommended to ignore PAWS because 1581 "their cleanup function should take precedence over timestamps." 1582 Certainly, it is mistake. It is necessary to understand the reasons 1583 of this constraint to relax it: if peer reboots, clock may go 1584 out-of-sync and half-open connections will not be reset. 1585 Actually, the problem would be not existing if all 1586 the implementations followed draft about maintaining clock 1587 via reboots. Linux-2.2 DOES NOT! 1588 1589 However, we can relax time bounds for RST segments to MSL. 1590 */ 1591 if (rst && !time_before32(ktime_get_seconds(), 1592 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1593 return false; 1594 return true; 1595 } 1596 1597 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1598 int mib_idx, u32 *last_oow_ack_time); 1599 1600 static inline void tcp_mib_init(struct net *net) 1601 { 1602 /* See RFC 2012 */ 1603 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1604 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1605 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1606 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1607 } 1608 1609 /* from STCP */ 1610 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1611 { 1612 tp->lost_skb_hint = NULL; 1613 } 1614 1615 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1616 { 1617 tcp_clear_retrans_hints_partial(tp); 1618 tp->retransmit_skb_hint = NULL; 1619 } 1620 1621 union tcp_md5_addr { 1622 struct in_addr a4; 1623 #if IS_ENABLED(CONFIG_IPV6) 1624 struct in6_addr a6; 1625 #endif 1626 }; 1627 1628 /* - key database */ 1629 struct tcp_md5sig_key { 1630 struct hlist_node node; 1631 u8 keylen; 1632 u8 family; /* AF_INET or AF_INET6 */ 1633 u8 prefixlen; 1634 u8 flags; 1635 union tcp_md5_addr addr; 1636 int l3index; /* set if key added with L3 scope */ 1637 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1638 struct rcu_head rcu; 1639 }; 1640 1641 /* - sock block */ 1642 struct tcp_md5sig_info { 1643 struct hlist_head head; 1644 struct rcu_head rcu; 1645 }; 1646 1647 /* - pseudo header */ 1648 struct tcp4_pseudohdr { 1649 __be32 saddr; 1650 __be32 daddr; 1651 __u8 pad; 1652 __u8 protocol; 1653 __be16 len; 1654 }; 1655 1656 struct tcp6_pseudohdr { 1657 struct in6_addr saddr; 1658 struct in6_addr daddr; 1659 __be32 len; 1660 __be32 protocol; /* including padding */ 1661 }; 1662 1663 union tcp_md5sum_block { 1664 struct tcp4_pseudohdr ip4; 1665 #if IS_ENABLED(CONFIG_IPV6) 1666 struct tcp6_pseudohdr ip6; 1667 #endif 1668 }; 1669 1670 /* - pool: digest algorithm, hash description and scratch buffer */ 1671 struct tcp_md5sig_pool { 1672 struct ahash_request *md5_req; 1673 void *scratch; 1674 }; 1675 1676 /* - functions */ 1677 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1678 const struct sock *sk, const struct sk_buff *skb); 1679 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1680 int family, u8 prefixlen, int l3index, u8 flags, 1681 const u8 *newkey, u8 newkeylen); 1682 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1683 int family, u8 prefixlen, int l3index, 1684 struct tcp_md5sig_key *key); 1685 1686 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1687 int family, u8 prefixlen, int l3index, u8 flags); 1688 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1689 const struct sock *addr_sk); 1690 1691 #ifdef CONFIG_TCP_MD5SIG 1692 #include <linux/jump_label.h> 1693 extern struct static_key_false_deferred tcp_md5_needed; 1694 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1695 const union tcp_md5_addr *addr, 1696 int family); 1697 static inline struct tcp_md5sig_key * 1698 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1699 const union tcp_md5_addr *addr, int family) 1700 { 1701 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1702 return NULL; 1703 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1704 } 1705 1706 enum skb_drop_reason 1707 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1708 const void *saddr, const void *daddr, 1709 int family, int dif, int sdif); 1710 1711 1712 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1713 #else 1714 static inline struct tcp_md5sig_key * 1715 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1716 const union tcp_md5_addr *addr, int family) 1717 { 1718 return NULL; 1719 } 1720 1721 static inline enum skb_drop_reason 1722 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1723 const void *saddr, const void *daddr, 1724 int family, int dif, int sdif) 1725 { 1726 return SKB_NOT_DROPPED_YET; 1727 } 1728 #define tcp_twsk_md5_key(twsk) NULL 1729 #endif 1730 1731 bool tcp_alloc_md5sig_pool(void); 1732 1733 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1734 static inline void tcp_put_md5sig_pool(void) 1735 { 1736 local_bh_enable(); 1737 } 1738 1739 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1740 unsigned int header_len); 1741 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1742 const struct tcp_md5sig_key *key); 1743 1744 /* From tcp_fastopen.c */ 1745 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1746 struct tcp_fastopen_cookie *cookie); 1747 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1748 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1749 u16 try_exp); 1750 struct tcp_fastopen_request { 1751 /* Fast Open cookie. Size 0 means a cookie request */ 1752 struct tcp_fastopen_cookie cookie; 1753 struct msghdr *data; /* data in MSG_FASTOPEN */ 1754 size_t size; 1755 int copied; /* queued in tcp_connect() */ 1756 struct ubuf_info *uarg; 1757 }; 1758 void tcp_free_fastopen_req(struct tcp_sock *tp); 1759 void tcp_fastopen_destroy_cipher(struct sock *sk); 1760 void tcp_fastopen_ctx_destroy(struct net *net); 1761 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1762 void *primary_key, void *backup_key); 1763 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1764 u64 *key); 1765 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1766 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1767 struct request_sock *req, 1768 struct tcp_fastopen_cookie *foc, 1769 const struct dst_entry *dst); 1770 void tcp_fastopen_init_key_once(struct net *net); 1771 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1772 struct tcp_fastopen_cookie *cookie); 1773 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1774 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1775 #define TCP_FASTOPEN_KEY_MAX 2 1776 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1777 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1778 1779 /* Fastopen key context */ 1780 struct tcp_fastopen_context { 1781 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1782 int num; 1783 struct rcu_head rcu; 1784 }; 1785 1786 void tcp_fastopen_active_disable(struct sock *sk); 1787 bool tcp_fastopen_active_should_disable(struct sock *sk); 1788 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1789 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1790 1791 /* Caller needs to wrap with rcu_read_(un)lock() */ 1792 static inline 1793 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1794 { 1795 struct tcp_fastopen_context *ctx; 1796 1797 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1798 if (!ctx) 1799 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1800 return ctx; 1801 } 1802 1803 static inline 1804 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1805 const struct tcp_fastopen_cookie *orig) 1806 { 1807 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1808 orig->len == foc->len && 1809 !memcmp(orig->val, foc->val, foc->len)) 1810 return true; 1811 return false; 1812 } 1813 1814 static inline 1815 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1816 { 1817 return ctx->num; 1818 } 1819 1820 /* Latencies incurred by various limits for a sender. They are 1821 * chronograph-like stats that are mutually exclusive. 1822 */ 1823 enum tcp_chrono { 1824 TCP_CHRONO_UNSPEC, 1825 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1826 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1827 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1828 __TCP_CHRONO_MAX, 1829 }; 1830 1831 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1832 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1833 1834 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1835 * the same memory storage than skb->destructor/_skb_refdst 1836 */ 1837 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1838 { 1839 skb->destructor = NULL; 1840 skb->_skb_refdst = 0UL; 1841 } 1842 1843 #define tcp_skb_tsorted_save(skb) { \ 1844 unsigned long _save = skb->_skb_refdst; \ 1845 skb->_skb_refdst = 0UL; 1846 1847 #define tcp_skb_tsorted_restore(skb) \ 1848 skb->_skb_refdst = _save; \ 1849 } 1850 1851 void tcp_write_queue_purge(struct sock *sk); 1852 1853 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1854 { 1855 return skb_rb_first(&sk->tcp_rtx_queue); 1856 } 1857 1858 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1859 { 1860 return skb_rb_last(&sk->tcp_rtx_queue); 1861 } 1862 1863 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1864 { 1865 return skb_peek_tail(&sk->sk_write_queue); 1866 } 1867 1868 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1869 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1870 1871 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1872 { 1873 return skb_peek(&sk->sk_write_queue); 1874 } 1875 1876 static inline bool tcp_skb_is_last(const struct sock *sk, 1877 const struct sk_buff *skb) 1878 { 1879 return skb_queue_is_last(&sk->sk_write_queue, skb); 1880 } 1881 1882 /** 1883 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1884 * @sk: socket 1885 * 1886 * Since the write queue can have a temporary empty skb in it, 1887 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1888 */ 1889 static inline bool tcp_write_queue_empty(const struct sock *sk) 1890 { 1891 const struct tcp_sock *tp = tcp_sk(sk); 1892 1893 return tp->write_seq == tp->snd_nxt; 1894 } 1895 1896 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1897 { 1898 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1899 } 1900 1901 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1902 { 1903 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1904 } 1905 1906 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1907 { 1908 __skb_queue_tail(&sk->sk_write_queue, skb); 1909 1910 /* Queue it, remembering where we must start sending. */ 1911 if (sk->sk_write_queue.next == skb) 1912 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1913 } 1914 1915 /* Insert new before skb on the write queue of sk. */ 1916 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1917 struct sk_buff *skb, 1918 struct sock *sk) 1919 { 1920 __skb_queue_before(&sk->sk_write_queue, skb, new); 1921 } 1922 1923 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1924 { 1925 tcp_skb_tsorted_anchor_cleanup(skb); 1926 __skb_unlink(skb, &sk->sk_write_queue); 1927 } 1928 1929 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1930 1931 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1932 { 1933 tcp_skb_tsorted_anchor_cleanup(skb); 1934 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1935 } 1936 1937 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1938 { 1939 list_del(&skb->tcp_tsorted_anchor); 1940 tcp_rtx_queue_unlink(skb, sk); 1941 tcp_wmem_free_skb(sk, skb); 1942 } 1943 1944 static inline void tcp_push_pending_frames(struct sock *sk) 1945 { 1946 if (tcp_send_head(sk)) { 1947 struct tcp_sock *tp = tcp_sk(sk); 1948 1949 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1950 } 1951 } 1952 1953 /* Start sequence of the skb just after the highest skb with SACKed 1954 * bit, valid only if sacked_out > 0 or when the caller has ensured 1955 * validity by itself. 1956 */ 1957 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1958 { 1959 if (!tp->sacked_out) 1960 return tp->snd_una; 1961 1962 if (tp->highest_sack == NULL) 1963 return tp->snd_nxt; 1964 1965 return TCP_SKB_CB(tp->highest_sack)->seq; 1966 } 1967 1968 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1969 { 1970 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 1971 } 1972 1973 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1974 { 1975 return tcp_sk(sk)->highest_sack; 1976 } 1977 1978 static inline void tcp_highest_sack_reset(struct sock *sk) 1979 { 1980 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 1981 } 1982 1983 /* Called when old skb is about to be deleted and replaced by new skb */ 1984 static inline void tcp_highest_sack_replace(struct sock *sk, 1985 struct sk_buff *old, 1986 struct sk_buff *new) 1987 { 1988 if (old == tcp_highest_sack(sk)) 1989 tcp_sk(sk)->highest_sack = new; 1990 } 1991 1992 /* This helper checks if socket has IP_TRANSPARENT set */ 1993 static inline bool inet_sk_transparent(const struct sock *sk) 1994 { 1995 switch (sk->sk_state) { 1996 case TCP_TIME_WAIT: 1997 return inet_twsk(sk)->tw_transparent; 1998 case TCP_NEW_SYN_RECV: 1999 return inet_rsk(inet_reqsk(sk))->no_srccheck; 2000 } 2001 return inet_sk(sk)->transparent; 2002 } 2003 2004 /* Determines whether this is a thin stream (which may suffer from 2005 * increased latency). Used to trigger latency-reducing mechanisms. 2006 */ 2007 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 2008 { 2009 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 2010 } 2011 2012 /* /proc */ 2013 enum tcp_seq_states { 2014 TCP_SEQ_STATE_LISTENING, 2015 TCP_SEQ_STATE_ESTABLISHED, 2016 }; 2017 2018 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 2019 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 2020 void tcp_seq_stop(struct seq_file *seq, void *v); 2021 2022 struct tcp_seq_afinfo { 2023 sa_family_t family; 2024 }; 2025 2026 struct tcp_iter_state { 2027 struct seq_net_private p; 2028 enum tcp_seq_states state; 2029 struct sock *syn_wait_sk; 2030 int bucket, offset, sbucket, num; 2031 loff_t last_pos; 2032 }; 2033 2034 extern struct request_sock_ops tcp_request_sock_ops; 2035 extern struct request_sock_ops tcp6_request_sock_ops; 2036 2037 void tcp_v4_destroy_sock(struct sock *sk); 2038 2039 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 2040 netdev_features_t features); 2041 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 2042 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 2043 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 2044 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 2045 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 2046 void tcp_gro_complete(struct sk_buff *skb); 2047 2048 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 2049 2050 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 2051 { 2052 struct net *net = sock_net((struct sock *)tp); 2053 return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); 2054 } 2055 2056 bool tcp_stream_memory_free(const struct sock *sk, int wake); 2057 2058 #ifdef CONFIG_PROC_FS 2059 int tcp4_proc_init(void); 2060 void tcp4_proc_exit(void); 2061 #endif 2062 2063 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2064 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2065 const struct tcp_request_sock_ops *af_ops, 2066 struct sock *sk, struct sk_buff *skb); 2067 2068 /* TCP af-specific functions */ 2069 struct tcp_sock_af_ops { 2070 #ifdef CONFIG_TCP_MD5SIG 2071 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2072 const struct sock *addr_sk); 2073 int (*calc_md5_hash)(char *location, 2074 const struct tcp_md5sig_key *md5, 2075 const struct sock *sk, 2076 const struct sk_buff *skb); 2077 int (*md5_parse)(struct sock *sk, 2078 int optname, 2079 sockptr_t optval, 2080 int optlen); 2081 #endif 2082 }; 2083 2084 struct tcp_request_sock_ops { 2085 u16 mss_clamp; 2086 #ifdef CONFIG_TCP_MD5SIG 2087 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2088 const struct sock *addr_sk); 2089 int (*calc_md5_hash) (char *location, 2090 const struct tcp_md5sig_key *md5, 2091 const struct sock *sk, 2092 const struct sk_buff *skb); 2093 #endif 2094 #ifdef CONFIG_SYN_COOKIES 2095 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2096 __u16 *mss); 2097 #endif 2098 struct dst_entry *(*route_req)(const struct sock *sk, 2099 struct sk_buff *skb, 2100 struct flowi *fl, 2101 struct request_sock *req); 2102 u32 (*init_seq)(const struct sk_buff *skb); 2103 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2104 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2105 struct flowi *fl, struct request_sock *req, 2106 struct tcp_fastopen_cookie *foc, 2107 enum tcp_synack_type synack_type, 2108 struct sk_buff *syn_skb); 2109 }; 2110 2111 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2112 #if IS_ENABLED(CONFIG_IPV6) 2113 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2114 #endif 2115 2116 #ifdef CONFIG_SYN_COOKIES 2117 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2118 const struct sock *sk, struct sk_buff *skb, 2119 __u16 *mss) 2120 { 2121 tcp_synq_overflow(sk); 2122 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2123 return ops->cookie_init_seq(skb, mss); 2124 } 2125 #else 2126 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2127 const struct sock *sk, struct sk_buff *skb, 2128 __u16 *mss) 2129 { 2130 return 0; 2131 } 2132 #endif 2133 2134 int tcpv4_offload_init(void); 2135 2136 void tcp_v4_init(void); 2137 void tcp_init(void); 2138 2139 /* tcp_recovery.c */ 2140 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2141 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2142 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2143 u32 reo_wnd); 2144 extern bool tcp_rack_mark_lost(struct sock *sk); 2145 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2146 u64 xmit_time); 2147 extern void tcp_rack_reo_timeout(struct sock *sk); 2148 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2149 2150 /* tcp_plb.c */ 2151 2152 /* 2153 * Scaling factor for fractions in PLB. For example, tcp_plb_update_state 2154 * expects cong_ratio which represents fraction of traffic that experienced 2155 * congestion over a single RTT. In order to avoid floating point operations, 2156 * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in. 2157 */ 2158 #define TCP_PLB_SCALE 8 2159 2160 /* State for PLB (Protective Load Balancing) for a single TCP connection. */ 2161 struct tcp_plb_state { 2162 u8 consec_cong_rounds:5, /* consecutive congested rounds */ 2163 unused:3; 2164 u32 pause_until; /* jiffies32 when PLB can resume rerouting */ 2165 }; 2166 2167 static inline void tcp_plb_init(const struct sock *sk, 2168 struct tcp_plb_state *plb) 2169 { 2170 plb->consec_cong_rounds = 0; 2171 plb->pause_until = 0; 2172 } 2173 void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb, 2174 const int cong_ratio); 2175 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb); 2176 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb); 2177 2178 /* At how many usecs into the future should the RTO fire? */ 2179 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2180 { 2181 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2182 u32 rto = inet_csk(sk)->icsk_rto; 2183 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2184 2185 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2186 } 2187 2188 /* 2189 * Save and compile IPv4 options, return a pointer to it 2190 */ 2191 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2192 struct sk_buff *skb) 2193 { 2194 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2195 struct ip_options_rcu *dopt = NULL; 2196 2197 if (opt->optlen) { 2198 int opt_size = sizeof(*dopt) + opt->optlen; 2199 2200 dopt = kmalloc(opt_size, GFP_ATOMIC); 2201 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2202 kfree(dopt); 2203 dopt = NULL; 2204 } 2205 } 2206 return dopt; 2207 } 2208 2209 /* locally generated TCP pure ACKs have skb->truesize == 2 2210 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2211 * This is much faster than dissecting the packet to find out. 2212 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2213 */ 2214 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2215 { 2216 return skb->truesize == 2; 2217 } 2218 2219 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2220 { 2221 skb->truesize = 2; 2222 } 2223 2224 static inline int tcp_inq(struct sock *sk) 2225 { 2226 struct tcp_sock *tp = tcp_sk(sk); 2227 int answ; 2228 2229 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2230 answ = 0; 2231 } else if (sock_flag(sk, SOCK_URGINLINE) || 2232 !tp->urg_data || 2233 before(tp->urg_seq, tp->copied_seq) || 2234 !before(tp->urg_seq, tp->rcv_nxt)) { 2235 2236 answ = tp->rcv_nxt - tp->copied_seq; 2237 2238 /* Subtract 1, if FIN was received */ 2239 if (answ && sock_flag(sk, SOCK_DONE)) 2240 answ--; 2241 } else { 2242 answ = tp->urg_seq - tp->copied_seq; 2243 } 2244 2245 return answ; 2246 } 2247 2248 int tcp_peek_len(struct socket *sock); 2249 2250 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2251 { 2252 u16 segs_in; 2253 2254 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2255 2256 /* We update these fields while other threads might 2257 * read them from tcp_get_info() 2258 */ 2259 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2260 if (skb->len > tcp_hdrlen(skb)) 2261 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2262 } 2263 2264 /* 2265 * TCP listen path runs lockless. 2266 * We forced "struct sock" to be const qualified to make sure 2267 * we don't modify one of its field by mistake. 2268 * Here, we increment sk_drops which is an atomic_t, so we can safely 2269 * make sock writable again. 2270 */ 2271 static inline void tcp_listendrop(const struct sock *sk) 2272 { 2273 atomic_inc(&((struct sock *)sk)->sk_drops); 2274 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2275 } 2276 2277 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2278 2279 /* 2280 * Interface for adding Upper Level Protocols over TCP 2281 */ 2282 2283 #define TCP_ULP_NAME_MAX 16 2284 #define TCP_ULP_MAX 128 2285 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2286 2287 struct tcp_ulp_ops { 2288 struct list_head list; 2289 2290 /* initialize ulp */ 2291 int (*init)(struct sock *sk); 2292 /* update ulp */ 2293 void (*update)(struct sock *sk, struct proto *p, 2294 void (*write_space)(struct sock *sk)); 2295 /* cleanup ulp */ 2296 void (*release)(struct sock *sk); 2297 /* diagnostic */ 2298 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2299 size_t (*get_info_size)(const struct sock *sk); 2300 /* clone ulp */ 2301 void (*clone)(const struct request_sock *req, struct sock *newsk, 2302 const gfp_t priority); 2303 2304 char name[TCP_ULP_NAME_MAX]; 2305 struct module *owner; 2306 }; 2307 int tcp_register_ulp(struct tcp_ulp_ops *type); 2308 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2309 int tcp_set_ulp(struct sock *sk, const char *name); 2310 void tcp_get_available_ulp(char *buf, size_t len); 2311 void tcp_cleanup_ulp(struct sock *sk); 2312 void tcp_update_ulp(struct sock *sk, struct proto *p, 2313 void (*write_space)(struct sock *sk)); 2314 2315 #define MODULE_ALIAS_TCP_ULP(name) \ 2316 __MODULE_INFO(alias, alias_userspace, name); \ 2317 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2318 2319 #ifdef CONFIG_NET_SOCK_MSG 2320 struct sk_msg; 2321 struct sk_psock; 2322 2323 #ifdef CONFIG_BPF_SYSCALL 2324 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 2325 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2326 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2327 #endif /* CONFIG_BPF_SYSCALL */ 2328 2329 #ifdef CONFIG_INET 2330 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); 2331 #else 2332 static inline void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) 2333 { 2334 } 2335 #endif 2336 2337 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 2338 struct sk_msg *msg, u32 bytes, int flags); 2339 #endif /* CONFIG_NET_SOCK_MSG */ 2340 2341 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2342 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2343 { 2344 } 2345 #endif 2346 2347 #ifdef CONFIG_CGROUP_BPF 2348 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2349 struct sk_buff *skb, 2350 unsigned int end_offset) 2351 { 2352 skops->skb = skb; 2353 skops->skb_data_end = skb->data + end_offset; 2354 } 2355 #else 2356 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2357 struct sk_buff *skb, 2358 unsigned int end_offset) 2359 { 2360 } 2361 #endif 2362 2363 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2364 * is < 0, then the BPF op failed (for example if the loaded BPF 2365 * program does not support the chosen operation or there is no BPF 2366 * program loaded). 2367 */ 2368 #ifdef CONFIG_BPF 2369 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2370 { 2371 struct bpf_sock_ops_kern sock_ops; 2372 int ret; 2373 2374 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2375 if (sk_fullsock(sk)) { 2376 sock_ops.is_fullsock = 1; 2377 sock_owned_by_me(sk); 2378 } 2379 2380 sock_ops.sk = sk; 2381 sock_ops.op = op; 2382 if (nargs > 0) 2383 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2384 2385 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2386 if (ret == 0) 2387 ret = sock_ops.reply; 2388 else 2389 ret = -1; 2390 return ret; 2391 } 2392 2393 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2394 { 2395 u32 args[2] = {arg1, arg2}; 2396 2397 return tcp_call_bpf(sk, op, 2, args); 2398 } 2399 2400 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2401 u32 arg3) 2402 { 2403 u32 args[3] = {arg1, arg2, arg3}; 2404 2405 return tcp_call_bpf(sk, op, 3, args); 2406 } 2407 2408 #else 2409 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2410 { 2411 return -EPERM; 2412 } 2413 2414 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2415 { 2416 return -EPERM; 2417 } 2418 2419 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2420 u32 arg3) 2421 { 2422 return -EPERM; 2423 } 2424 2425 #endif 2426 2427 static inline u32 tcp_timeout_init(struct sock *sk) 2428 { 2429 int timeout; 2430 2431 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2432 2433 if (timeout <= 0) 2434 timeout = TCP_TIMEOUT_INIT; 2435 return min_t(int, timeout, TCP_RTO_MAX); 2436 } 2437 2438 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2439 { 2440 int rwnd; 2441 2442 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2443 2444 if (rwnd < 0) 2445 rwnd = 0; 2446 return rwnd; 2447 } 2448 2449 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2450 { 2451 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2452 } 2453 2454 static inline void tcp_bpf_rtt(struct sock *sk) 2455 { 2456 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2457 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2458 } 2459 2460 #if IS_ENABLED(CONFIG_SMC) 2461 extern struct static_key_false tcp_have_smc; 2462 #endif 2463 2464 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2465 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2466 void (*cad)(struct sock *sk, u32 ack_seq)); 2467 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2468 void clean_acked_data_flush(void); 2469 #endif 2470 2471 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2472 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2473 const struct tcp_sock *tp) 2474 { 2475 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2476 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2477 } 2478 2479 /* Compute Earliest Departure Time for some control packets 2480 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2481 */ 2482 static inline u64 tcp_transmit_time(const struct sock *sk) 2483 { 2484 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2485 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2486 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2487 2488 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2489 } 2490 return 0; 2491 } 2492 2493 #endif /* _TCP_H */ 2494