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 */ 144 145 #define TCP_TIMEOUT_MIN_US (2*USEC_PER_MSEC) /* Min TCP timeout in microsecs */ 146 147 #define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */ 148 #define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now 149 * used as a fallback RTO for the 150 * initial data transmission if no 151 * valid RTT sample has been acquired, 152 * most likely due to retrans in 3WHS. 153 */ 154 155 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 156 * for local resources. 157 */ 158 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 159 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 160 #define TCP_KEEPALIVE_INTVL (75*HZ) 161 162 #define MAX_TCP_KEEPIDLE 32767 163 #define MAX_TCP_KEEPINTVL 32767 164 #define MAX_TCP_KEEPCNT 127 165 #define MAX_TCP_SYNCNT 127 166 167 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 168 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 169 * after this time. It should be equal 170 * (or greater than) TCP_TIMEWAIT_LEN 171 * to provide reliability equal to one 172 * provided by timewait state. 173 */ 174 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 175 * timestamps. It must be less than 176 * minimal timewait lifetime. 177 */ 178 /* 179 * TCP option 180 */ 181 182 #define TCPOPT_NOP 1 /* Padding */ 183 #define TCPOPT_EOL 0 /* End of options */ 184 #define TCPOPT_MSS 2 /* Segment size negotiating */ 185 #define TCPOPT_WINDOW 3 /* Window scaling */ 186 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 187 #define TCPOPT_SACK 5 /* SACK Block */ 188 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 189 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 190 #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ 191 #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ 192 #define TCPOPT_EXP 254 /* Experimental */ 193 /* Magic number to be after the option value for sharing TCP 194 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt 195 */ 196 #define TCPOPT_FASTOPEN_MAGIC 0xF989 197 #define TCPOPT_SMC_MAGIC 0xE2D4C3D9 198 199 /* 200 * TCP option lengths 201 */ 202 203 #define TCPOLEN_MSS 4 204 #define TCPOLEN_WINDOW 3 205 #define TCPOLEN_SACK_PERM 2 206 #define TCPOLEN_TIMESTAMP 10 207 #define TCPOLEN_MD5SIG 18 208 #define TCPOLEN_FASTOPEN_BASE 2 209 #define TCPOLEN_EXP_FASTOPEN_BASE 4 210 #define TCPOLEN_EXP_SMC_BASE 6 211 212 /* But this is what stacks really send out. */ 213 #define TCPOLEN_TSTAMP_ALIGNED 12 214 #define TCPOLEN_WSCALE_ALIGNED 4 215 #define TCPOLEN_SACKPERM_ALIGNED 4 216 #define TCPOLEN_SACK_BASE 2 217 #define TCPOLEN_SACK_BASE_ALIGNED 4 218 #define TCPOLEN_SACK_PERBLOCK 8 219 #define TCPOLEN_MD5SIG_ALIGNED 20 220 #define TCPOLEN_MSS_ALIGNED 4 221 #define TCPOLEN_EXP_SMC_BASE_ALIGNED 8 222 223 /* Flags in tp->nonagle */ 224 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 225 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 226 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 227 228 /* TCP thin-stream limits */ 229 #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ 230 231 /* TCP initial congestion window as per rfc6928 */ 232 #define TCP_INIT_CWND 10 233 234 /* Bit Flags for sysctl_tcp_fastopen */ 235 #define TFO_CLIENT_ENABLE 1 236 #define TFO_SERVER_ENABLE 2 237 #define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */ 238 239 /* Accept SYN data w/o any cookie option */ 240 #define TFO_SERVER_COOKIE_NOT_REQD 0x200 241 242 /* Force enable TFO on all listeners, i.e., not requiring the 243 * TCP_FASTOPEN socket option. 244 */ 245 #define TFO_SERVER_WO_SOCKOPT1 0x400 246 247 248 /* sysctl variables for tcp */ 249 extern int sysctl_tcp_max_orphans; 250 extern long sysctl_tcp_mem[3]; 251 252 #define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */ 253 #define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */ 254 #define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */ 255 256 extern atomic_long_t tcp_memory_allocated; 257 DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc); 258 259 extern struct percpu_counter tcp_sockets_allocated; 260 extern unsigned long tcp_memory_pressure; 261 262 /* optimized version of sk_under_memory_pressure() for TCP sockets */ 263 static inline bool tcp_under_memory_pressure(const struct sock *sk) 264 { 265 if (mem_cgroup_sockets_enabled && sk->sk_memcg && 266 mem_cgroup_under_socket_pressure(sk->sk_memcg)) 267 return true; 268 269 return READ_ONCE(tcp_memory_pressure); 270 } 271 /* 272 * The next routines deal with comparing 32 bit unsigned ints 273 * and worry about wraparound (automatic with unsigned arithmetic). 274 */ 275 276 static inline bool before(__u32 seq1, __u32 seq2) 277 { 278 return (__s32)(seq1-seq2) < 0; 279 } 280 #define after(seq2, seq1) before(seq1, seq2) 281 282 /* is s2<=s1<=s3 ? */ 283 static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3) 284 { 285 return seq3 - seq2 >= seq1 - seq2; 286 } 287 288 static inline bool tcp_out_of_memory(struct sock *sk) 289 { 290 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 291 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2)) 292 return true; 293 return false; 294 } 295 296 static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb) 297 { 298 sk_wmem_queued_add(sk, -skb->truesize); 299 if (!skb_zcopy_pure(skb)) 300 sk_mem_uncharge(sk, skb->truesize); 301 else 302 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb))); 303 __kfree_skb(skb); 304 } 305 306 void sk_forced_mem_schedule(struct sock *sk, int size); 307 308 bool tcp_check_oom(struct sock *sk, int shift); 309 310 311 extern struct proto tcp_prot; 312 313 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 314 #define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field) 315 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 316 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) 317 318 void tcp_tasklet_init(void); 319 320 int tcp_v4_err(struct sk_buff *skb, u32); 321 322 void tcp_shutdown(struct sock *sk, int how); 323 324 int tcp_v4_early_demux(struct sk_buff *skb); 325 int tcp_v4_rcv(struct sk_buff *skb); 326 327 void tcp_remove_empty_skb(struct sock *sk); 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_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, 331 size_t size, struct ubuf_info *uarg); 332 void tcp_splice_eof(struct socket *sock); 333 int tcp_send_mss(struct sock *sk, int *size_goal, int flags); 334 int tcp_wmem_schedule(struct sock *sk, int copy); 335 void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, 336 int size_goal); 337 void tcp_release_cb(struct sock *sk); 338 void tcp_wfree(struct sk_buff *skb); 339 void tcp_write_timer_handler(struct sock *sk); 340 void tcp_delack_timer_handler(struct sock *sk); 341 int tcp_ioctl(struct sock *sk, int cmd, int *karg); 342 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb); 343 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); 344 void tcp_rcv_space_adjust(struct sock *sk); 345 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); 346 void tcp_twsk_destructor(struct sock *sk); 347 void tcp_twsk_purge(struct list_head *net_exit_list, int family); 348 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 349 struct pipe_inode_info *pipe, size_t len, 350 unsigned int flags); 351 struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp, 352 bool force_schedule); 353 354 static inline void tcp_dec_quickack_mode(struct sock *sk) 355 { 356 struct inet_connection_sock *icsk = inet_csk(sk); 357 358 if (icsk->icsk_ack.quick) { 359 /* How many ACKs S/ACKing new data have we sent? */ 360 const unsigned int pkts = inet_csk_ack_scheduled(sk) ? 1 : 0; 361 362 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 int tcp_write_wakeup(struct sock *, int mib); 612 void tcp_send_fin(struct sock *sk); 613 void tcp_send_active_reset(struct sock *sk, gfp_t priority); 614 int tcp_send_synack(struct sock *); 615 void tcp_push_one(struct sock *, unsigned int mss_now); 616 void __tcp_send_ack(struct sock *sk, u32 rcv_nxt); 617 void tcp_send_ack(struct sock *sk); 618 void tcp_send_delayed_ack(struct sock *sk); 619 void tcp_send_loss_probe(struct sock *sk); 620 bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto); 621 void tcp_skb_collapse_tstamp(struct sk_buff *skb, 622 const struct sk_buff *next_skb); 623 624 /* tcp_input.c */ 625 void tcp_rearm_rto(struct sock *sk); 626 void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req); 627 void tcp_reset(struct sock *sk, struct sk_buff *skb); 628 void tcp_fin(struct sock *sk); 629 void tcp_check_space(struct sock *sk); 630 void tcp_sack_compress_send_ack(struct sock *sk); 631 632 /* tcp_timer.c */ 633 void tcp_init_xmit_timers(struct sock *); 634 static inline void tcp_clear_xmit_timers(struct sock *sk) 635 { 636 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) 637 __sock_put(sk); 638 639 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) 640 __sock_put(sk); 641 642 inet_csk_clear_xmit_timers(sk); 643 } 644 645 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 646 unsigned int tcp_current_mss(struct sock *sk); 647 u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when); 648 649 /* Bound MSS / TSO packet size with the half of the window */ 650 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 651 { 652 int cutoff; 653 654 /* When peer uses tiny windows, there is no use in packetizing 655 * to sub-MSS pieces for the sake of SWS or making sure there 656 * are enough packets in the pipe for fast recovery. 657 * 658 * On the other hand, for extremely large MSS devices, handling 659 * smaller than MSS windows in this way does make sense. 660 */ 661 if (tp->max_window > TCP_MSS_DEFAULT) 662 cutoff = (tp->max_window >> 1); 663 else 664 cutoff = tp->max_window; 665 666 if (cutoff && pktsize > cutoff) 667 return max_t(int, cutoff, 68U - tp->tcp_header_len); 668 else 669 return pktsize; 670 } 671 672 /* tcp.c */ 673 void tcp_get_info(struct sock *, struct tcp_info *); 674 675 /* Read 'sendfile()'-style from a TCP socket */ 676 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 677 sk_read_actor_t recv_actor); 678 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 679 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off); 680 void tcp_read_done(struct sock *sk, size_t len); 681 682 void tcp_initialize_rcv_mss(struct sock *sk); 683 684 int tcp_mtu_to_mss(struct sock *sk, int pmtu); 685 int tcp_mss_to_mtu(struct sock *sk, int mss); 686 void tcp_mtup_init(struct sock *sk); 687 688 static inline void tcp_bound_rto(const struct sock *sk) 689 { 690 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 691 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 692 } 693 694 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 695 { 696 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us); 697 } 698 699 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 700 { 701 /* mptcp hooks are only on the slow path */ 702 if (sk_is_mptcp((struct sock *)tp)) 703 return; 704 705 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 706 ntohl(TCP_FLAG_ACK) | 707 snd_wnd); 708 } 709 710 static inline void tcp_fast_path_on(struct tcp_sock *tp) 711 { 712 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 713 } 714 715 static inline void tcp_fast_path_check(struct sock *sk) 716 { 717 struct tcp_sock *tp = tcp_sk(sk); 718 719 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) && 720 tp->rcv_wnd && 721 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 722 !tp->urg_data) 723 tcp_fast_path_on(tp); 724 } 725 726 /* Compute the actual rto_min value */ 727 static inline u32 tcp_rto_min(struct sock *sk) 728 { 729 const struct dst_entry *dst = __sk_dst_get(sk); 730 u32 rto_min = inet_csk(sk)->icsk_rto_min; 731 732 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 733 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 734 return rto_min; 735 } 736 737 static inline u32 tcp_rto_min_us(struct sock *sk) 738 { 739 return jiffies_to_usecs(tcp_rto_min(sk)); 740 } 741 742 static inline bool tcp_ca_dst_locked(const struct dst_entry *dst) 743 { 744 return dst_metric_locked(dst, RTAX_CC_ALGO); 745 } 746 747 /* Minimum RTT in usec. ~0 means not available. */ 748 static inline u32 tcp_min_rtt(const struct tcp_sock *tp) 749 { 750 return minmax_get(&tp->rtt_min); 751 } 752 753 /* Compute the actual receive window we are currently advertising. 754 * Rcv_nxt can be after the window if our peer push more data 755 * than the offered window. 756 */ 757 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 758 { 759 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 760 761 if (win < 0) 762 win = 0; 763 return (u32) win; 764 } 765 766 /* Choose a new window, without checks for shrinking, and without 767 * scaling applied to the result. The caller does these things 768 * if necessary. This is a "raw" window selection. 769 */ 770 u32 __tcp_select_window(struct sock *sk); 771 772 void tcp_send_window_probe(struct sock *sk); 773 774 /* TCP uses 32bit jiffies to save some space. 775 * Note that this is different from tcp_time_stamp, which 776 * historically has been the same until linux-4.13. 777 */ 778 #define tcp_jiffies32 ((u32)jiffies) 779 780 /* 781 * Deliver a 32bit value for TCP timestamp option (RFC 7323) 782 * It is no longer tied to jiffies, but to 1 ms clock. 783 * Note: double check if you want to use tcp_jiffies32 instead of this. 784 */ 785 #define TCP_TS_HZ 1000 786 787 static inline u64 tcp_clock_ns(void) 788 { 789 return ktime_get_ns(); 790 } 791 792 static inline u64 tcp_clock_us(void) 793 { 794 return div_u64(tcp_clock_ns(), NSEC_PER_USEC); 795 } 796 797 /* This should only be used in contexts where tp->tcp_mstamp is up to date */ 798 static inline u32 tcp_time_stamp(const struct tcp_sock *tp) 799 { 800 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ); 801 } 802 803 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */ 804 static inline u32 tcp_ns_to_ts(u64 ns) 805 { 806 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ); 807 } 808 809 /* Could use tcp_clock_us() / 1000, but this version uses a single divide */ 810 static inline u32 tcp_time_stamp_raw(void) 811 { 812 return tcp_ns_to_ts(tcp_clock_ns()); 813 } 814 815 void tcp_mstamp_refresh(struct tcp_sock *tp); 816 817 static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0) 818 { 819 return max_t(s64, t1 - t0, 0); 820 } 821 822 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 823 { 824 return tcp_ns_to_ts(skb->skb_mstamp_ns); 825 } 826 827 /* provide the departure time in us unit */ 828 static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb) 829 { 830 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC); 831 } 832 833 834 #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) 835 836 #define TCPHDR_FIN 0x01 837 #define TCPHDR_SYN 0x02 838 #define TCPHDR_RST 0x04 839 #define TCPHDR_PSH 0x08 840 #define TCPHDR_ACK 0x10 841 #define TCPHDR_URG 0x20 842 #define TCPHDR_ECE 0x40 843 #define TCPHDR_CWR 0x80 844 845 #define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR) 846 847 /* This is what the send packet queuing engine uses to pass 848 * TCP per-packet control information to the transmission code. 849 * We also store the host-order sequence numbers in here too. 850 * This is 44 bytes if IPV6 is enabled. 851 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. 852 */ 853 struct tcp_skb_cb { 854 __u32 seq; /* Starting sequence number */ 855 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 856 union { 857 /* Note : tcp_tw_isn is used in input path only 858 * (isn chosen by tcp_timewait_state_process()) 859 * 860 * tcp_gso_segs/size are used in write queue only, 861 * cf tcp_skb_pcount()/tcp_skb_mss() 862 */ 863 __u32 tcp_tw_isn; 864 struct { 865 u16 tcp_gso_segs; 866 u16 tcp_gso_size; 867 }; 868 }; 869 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ 870 871 __u8 sacked; /* State flags for SACK. */ 872 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 873 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 874 #define TCPCB_LOST 0x04 /* SKB is lost */ 875 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 876 #define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */ 877 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 878 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ 879 TCPCB_REPAIRED) 880 881 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ 882 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */ 883 eor:1, /* Is skb MSG_EOR marked? */ 884 has_rxtstamp:1, /* SKB has a RX timestamp */ 885 unused:5; 886 __u32 ack_seq; /* Sequence number ACK'd */ 887 union { 888 struct { 889 #define TCPCB_DELIVERED_CE_MASK ((1U<<20) - 1) 890 /* There is space for up to 24 bytes */ 891 __u32 is_app_limited:1, /* cwnd not fully used? */ 892 delivered_ce:20, 893 unused:11; 894 /* pkts S/ACKed so far upon tx of skb, incl retrans: */ 895 __u32 delivered; 896 /* start of send pipeline phase */ 897 u64 first_tx_mstamp; 898 /* when we reached the "delivered" count */ 899 u64 delivered_mstamp; 900 } tx; /* only used for outgoing skbs */ 901 union { 902 struct inet_skb_parm h4; 903 #if IS_ENABLED(CONFIG_IPV6) 904 struct inet6_skb_parm h6; 905 #endif 906 } header; /* For incoming skbs */ 907 }; 908 }; 909 910 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 911 912 extern const struct inet_connection_sock_af_ops ipv4_specific; 913 914 #if IS_ENABLED(CONFIG_IPV6) 915 /* This is the variant of inet6_iif() that must be used by TCP, 916 * as TCP moves IP6CB into a different location in skb->cb[] 917 */ 918 static inline int tcp_v6_iif(const struct sk_buff *skb) 919 { 920 return TCP_SKB_CB(skb)->header.h6.iif; 921 } 922 923 static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb) 924 { 925 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 926 927 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; 928 } 929 930 /* TCP_SKB_CB reference means this can not be used from early demux */ 931 static inline int tcp_v6_sdif(const struct sk_buff *skb) 932 { 933 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 934 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags)) 935 return TCP_SKB_CB(skb)->header.h6.iif; 936 #endif 937 return 0; 938 } 939 940 extern const struct inet_connection_sock_af_ops ipv6_specific; 941 942 INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)); 943 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); 944 void tcp_v6_early_demux(struct sk_buff *skb); 945 946 #endif 947 948 /* TCP_SKB_CB reference means this can not be used from early demux */ 949 static inline int tcp_v4_sdif(struct sk_buff *skb) 950 { 951 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 952 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) 953 return TCP_SKB_CB(skb)->header.h4.iif; 954 #endif 955 return 0; 956 } 957 958 /* Due to TSO, an SKB can be composed of multiple actual 959 * packets. To keep these tracked properly, we use this. 960 */ 961 static inline int tcp_skb_pcount(const struct sk_buff *skb) 962 { 963 return TCP_SKB_CB(skb)->tcp_gso_segs; 964 } 965 966 static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs) 967 { 968 TCP_SKB_CB(skb)->tcp_gso_segs = segs; 969 } 970 971 static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs) 972 { 973 TCP_SKB_CB(skb)->tcp_gso_segs += segs; 974 } 975 976 /* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */ 977 static inline int tcp_skb_mss(const struct sk_buff *skb) 978 { 979 return TCP_SKB_CB(skb)->tcp_gso_size; 980 } 981 982 static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) 983 { 984 return likely(!TCP_SKB_CB(skb)->eor); 985 } 986 987 static inline bool tcp_skb_can_collapse(const struct sk_buff *to, 988 const struct sk_buff *from) 989 { 990 return likely(tcp_skb_can_collapse_to(to) && 991 mptcp_skb_can_collapse(to, from) && 992 skb_pure_zcopy_same(to, from)); 993 } 994 995 /* Events passed to congestion control interface */ 996 enum tcp_ca_event { 997 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 998 CA_EVENT_CWND_RESTART, /* congestion window restart */ 999 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 1000 CA_EVENT_LOSS, /* loss timeout */ 1001 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */ 1002 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */ 1003 }; 1004 1005 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ 1006 enum tcp_ca_ack_event_flags { 1007 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ 1008 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ 1009 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ 1010 }; 1011 1012 /* 1013 * Interface for adding new TCP congestion control handlers 1014 */ 1015 #define TCP_CA_NAME_MAX 16 1016 #define TCP_CA_MAX 128 1017 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 1018 1019 #define TCP_CA_UNSPEC 0 1020 1021 /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ 1022 #define TCP_CONG_NON_RESTRICTED 0x1 1023 /* Requires ECN/ECT set on all packets */ 1024 #define TCP_CONG_NEEDS_ECN 0x2 1025 #define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN) 1026 1027 union tcp_cc_info; 1028 1029 struct ack_sample { 1030 u32 pkts_acked; 1031 s32 rtt_us; 1032 u32 in_flight; 1033 }; 1034 1035 /* A rate sample measures the number of (original/retransmitted) data 1036 * packets delivered "delivered" over an interval of time "interval_us". 1037 * The tcp_rate.c code fills in the rate sample, and congestion 1038 * control modules that define a cong_control function to run at the end 1039 * of ACK processing can optionally chose to consult this sample when 1040 * setting cwnd and pacing rate. 1041 * A sample is invalid if "delivered" or "interval_us" is negative. 1042 */ 1043 struct rate_sample { 1044 u64 prior_mstamp; /* starting timestamp for interval */ 1045 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 1046 u32 prior_delivered_ce;/* tp->delivered_ce at "prior_mstamp" */ 1047 s32 delivered; /* number of packets delivered over interval */ 1048 s32 delivered_ce; /* number of packets delivered w/ CE marks*/ 1049 long interval_us; /* time for tp->delivered to incr "delivered" */ 1050 u32 snd_interval_us; /* snd interval for delivered packets */ 1051 u32 rcv_interval_us; /* rcv interval for delivered packets */ 1052 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 1053 int losses; /* number of packets marked lost upon ACK */ 1054 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 1055 u32 prior_in_flight; /* in flight before this ACK */ 1056 u32 last_end_seq; /* end_seq of most recently ACKed packet */ 1057 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 1058 bool is_retrans; /* is sample from retransmission? */ 1059 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 1060 }; 1061 1062 struct tcp_congestion_ops { 1063 /* fast path fields are put first to fill one cache line */ 1064 1065 /* return slow start threshold (required) */ 1066 u32 (*ssthresh)(struct sock *sk); 1067 1068 /* do new cwnd calculation (required) */ 1069 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked); 1070 1071 /* call before changing ca_state (optional) */ 1072 void (*set_state)(struct sock *sk, u8 new_state); 1073 1074 /* call when cwnd event occurs (optional) */ 1075 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 1076 1077 /* call when ack arrives (optional) */ 1078 void (*in_ack_event)(struct sock *sk, u32 flags); 1079 1080 /* hook for packet ack accounting (optional) */ 1081 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 1082 1083 /* override sysctl_tcp_min_tso_segs */ 1084 u32 (*min_tso_segs)(struct sock *sk); 1085 1086 /* call when packets are delivered to update cwnd and pacing rate, 1087 * after all the ca_state processing. (optional) 1088 */ 1089 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 1090 1091 1092 /* new value of cwnd after loss (required) */ 1093 u32 (*undo_cwnd)(struct sock *sk); 1094 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 1095 u32 (*sndbuf_expand)(struct sock *sk); 1096 1097 /* control/slow paths put last */ 1098 /* get info for inet_diag (optional) */ 1099 size_t (*get_info)(struct sock *sk, u32 ext, int *attr, 1100 union tcp_cc_info *info); 1101 1102 char name[TCP_CA_NAME_MAX]; 1103 struct module *owner; 1104 struct list_head list; 1105 u32 key; 1106 u32 flags; 1107 1108 /* initialize private data (optional) */ 1109 void (*init)(struct sock *sk); 1110 /* cleanup private data (optional) */ 1111 void (*release)(struct sock *sk); 1112 } ____cacheline_aligned_in_smp; 1113 1114 int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1115 void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1116 int tcp_update_congestion_control(struct tcp_congestion_ops *type, 1117 struct tcp_congestion_ops *old_type); 1118 int tcp_validate_congestion_control(struct tcp_congestion_ops *ca); 1119 1120 void tcp_assign_congestion_control(struct sock *sk); 1121 void tcp_init_congestion_control(struct sock *sk); 1122 void tcp_cleanup_congestion_control(struct sock *sk); 1123 int tcp_set_default_congestion_control(struct net *net, const char *name); 1124 void tcp_get_default_congestion_control(struct net *net, char *name); 1125 void tcp_get_available_congestion_control(char *buf, size_t len); 1126 void tcp_get_allowed_congestion_control(char *buf, size_t len); 1127 int tcp_set_allowed_congestion_control(char *allowed); 1128 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, 1129 bool cap_net_admin); 1130 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); 1131 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); 1132 1133 u32 tcp_reno_ssthresh(struct sock *sk); 1134 u32 tcp_reno_undo_cwnd(struct sock *sk); 1135 void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); 1136 extern struct tcp_congestion_ops tcp_reno; 1137 1138 struct tcp_congestion_ops *tcp_ca_find(const char *name); 1139 struct tcp_congestion_ops *tcp_ca_find_key(u32 key); 1140 u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca); 1141 #ifdef CONFIG_INET 1142 char *tcp_ca_get_name_by_key(u32 key, char *buffer); 1143 #else 1144 static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer) 1145 { 1146 return NULL; 1147 } 1148 #endif 1149 1150 static inline bool tcp_ca_needs_ecn(const struct sock *sk) 1151 { 1152 const struct inet_connection_sock *icsk = inet_csk(sk); 1153 1154 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN; 1155 } 1156 1157 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 1158 { 1159 const struct inet_connection_sock *icsk = inet_csk(sk); 1160 1161 if (icsk->icsk_ca_ops->cwnd_event) 1162 icsk->icsk_ca_ops->cwnd_event(sk, event); 1163 } 1164 1165 /* From tcp_cong.c */ 1166 void tcp_set_ca_state(struct sock *sk, const u8 ca_state); 1167 1168 /* From tcp_rate.c */ 1169 void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb); 1170 void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 1171 struct rate_sample *rs); 1172 void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost, 1173 bool is_sack_reneg, struct rate_sample *rs); 1174 void tcp_rate_check_app_limited(struct sock *sk); 1175 1176 static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2) 1177 { 1178 return t1 > t2 || (t1 == t2 && after(seq1, seq2)); 1179 } 1180 1181 /* These functions determine how the current flow behaves in respect of SACK 1182 * handling. SACK is negotiated with the peer, and therefore it can vary 1183 * between different flows. 1184 * 1185 * tcp_is_sack - SACK enabled 1186 * tcp_is_reno - No SACK 1187 */ 1188 static inline int tcp_is_sack(const struct tcp_sock *tp) 1189 { 1190 return likely(tp->rx_opt.sack_ok); 1191 } 1192 1193 static inline bool tcp_is_reno(const struct tcp_sock *tp) 1194 { 1195 return !tcp_is_sack(tp); 1196 } 1197 1198 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 1199 { 1200 return tp->sacked_out + tp->lost_out; 1201 } 1202 1203 /* This determines how many packets are "in the network" to the best 1204 * of our knowledge. In many cases it is conservative, but where 1205 * detailed information is available from the receiver (via SACK 1206 * blocks etc.) we can make more aggressive calculations. 1207 * 1208 * Use this for decisions involving congestion control, use just 1209 * tp->packets_out to determine if the send queue is empty or not. 1210 * 1211 * Read this equation as: 1212 * 1213 * "Packets sent once on transmission queue" MINUS 1214 * "Packets left network, but not honestly ACKed yet" PLUS 1215 * "Packets fast retransmitted" 1216 */ 1217 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1218 { 1219 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 1220 } 1221 1222 #define TCP_INFINITE_SSTHRESH 0x7fffffff 1223 1224 static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp) 1225 { 1226 return tp->snd_cwnd; 1227 } 1228 1229 static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val) 1230 { 1231 WARN_ON_ONCE((int)val <= 0); 1232 tp->snd_cwnd = val; 1233 } 1234 1235 static inline bool tcp_in_slow_start(const struct tcp_sock *tp) 1236 { 1237 return tcp_snd_cwnd(tp) < tp->snd_ssthresh; 1238 } 1239 1240 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 1241 { 1242 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 1243 } 1244 1245 static inline bool tcp_in_cwnd_reduction(const struct sock *sk) 1246 { 1247 return (TCPF_CA_CWR | TCPF_CA_Recovery) & 1248 (1 << inet_csk(sk)->icsk_ca_state); 1249 } 1250 1251 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1252 * The exception is cwnd reduction phase, when cwnd is decreasing towards 1253 * ssthresh. 1254 */ 1255 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 1256 { 1257 const struct tcp_sock *tp = tcp_sk(sk); 1258 1259 if (tcp_in_cwnd_reduction(sk)) 1260 return tp->snd_ssthresh; 1261 else 1262 return max(tp->snd_ssthresh, 1263 ((tcp_snd_cwnd(tp) >> 1) + 1264 (tcp_snd_cwnd(tp) >> 2))); 1265 } 1266 1267 /* Use define here intentionally to get WARN_ON location shown at the caller */ 1268 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 1269 1270 void tcp_enter_cwr(struct sock *sk); 1271 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst); 1272 1273 /* The maximum number of MSS of available cwnd for which TSO defers 1274 * sending if not using sysctl_tcp_tso_win_divisor. 1275 */ 1276 static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp) 1277 { 1278 return 3; 1279 } 1280 1281 /* Returns end sequence number of the receiver's advertised window */ 1282 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 1283 { 1284 return tp->snd_una + tp->snd_wnd; 1285 } 1286 1287 /* We follow the spirit of RFC2861 to validate cwnd but implement a more 1288 * flexible approach. The RFC suggests cwnd should not be raised unless 1289 * it was fully used previously. And that's exactly what we do in 1290 * congestion avoidance mode. But in slow start we allow cwnd to grow 1291 * as long as the application has used half the cwnd. 1292 * Example : 1293 * cwnd is 10 (IW10), but application sends 9 frames. 1294 * We allow cwnd to reach 18 when all frames are ACKed. 1295 * This check is safe because it's as aggressive as slow start which already 1296 * risks 100% overshoot. The advantage is that we discourage application to 1297 * either send more filler packets or data to artificially blow up the cwnd 1298 * usage, and allow application-limited process to probe bw more aggressively. 1299 */ 1300 static inline bool tcp_is_cwnd_limited(const struct sock *sk) 1301 { 1302 const struct tcp_sock *tp = tcp_sk(sk); 1303 1304 if (tp->is_cwnd_limited) 1305 return true; 1306 1307 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 1308 if (tcp_in_slow_start(tp)) 1309 return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out; 1310 1311 return false; 1312 } 1313 1314 /* BBR congestion control needs pacing. 1315 * Same remark for SO_MAX_PACING_RATE. 1316 * sch_fq packet scheduler is efficiently handling pacing, 1317 * but is not always installed/used. 1318 * Return true if TCP stack should pace packets itself. 1319 */ 1320 static inline bool tcp_needs_internal_pacing(const struct sock *sk) 1321 { 1322 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; 1323 } 1324 1325 /* Estimates in how many jiffies next packet for this flow can be sent. 1326 * Scheduling a retransmit timer too early would be silly. 1327 */ 1328 static inline unsigned long tcp_pacing_delay(const struct sock *sk) 1329 { 1330 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache; 1331 1332 return delay > 0 ? nsecs_to_jiffies(delay) : 0; 1333 } 1334 1335 static inline void tcp_reset_xmit_timer(struct sock *sk, 1336 const int what, 1337 unsigned long when, 1338 const unsigned long max_when) 1339 { 1340 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk), 1341 max_when); 1342 } 1343 1344 /* Something is really bad, we could not queue an additional packet, 1345 * because qdisc is full or receiver sent a 0 window, or we are paced. 1346 * We do not want to add fuel to the fire, or abort too early, 1347 * so make sure the timer we arm now is at least 200ms in the future, 1348 * regardless of current icsk_rto value (as it could be ~2ms) 1349 */ 1350 static inline unsigned long tcp_probe0_base(const struct sock *sk) 1351 { 1352 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN); 1353 } 1354 1355 /* Variant of inet_csk_rto_backoff() used for zero window probes */ 1356 static inline unsigned long tcp_probe0_when(const struct sock *sk, 1357 unsigned long max_when) 1358 { 1359 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1, 1360 inet_csk(sk)->icsk_backoff); 1361 u64 when = (u64)tcp_probe0_base(sk) << backoff; 1362 1363 return (unsigned long)min_t(u64, when, max_when); 1364 } 1365 1366 static inline void tcp_check_probe_timer(struct sock *sk) 1367 { 1368 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending) 1369 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 1370 tcp_probe0_base(sk), TCP_RTO_MAX); 1371 } 1372 1373 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 1374 { 1375 tp->snd_wl1 = seq; 1376 } 1377 1378 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 1379 { 1380 tp->snd_wl1 = seq; 1381 } 1382 1383 /* 1384 * Calculate(/check) TCP checksum 1385 */ 1386 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 1387 __be32 daddr, __wsum base) 1388 { 1389 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base); 1390 } 1391 1392 static inline bool tcp_checksum_complete(struct sk_buff *skb) 1393 { 1394 return !skb_csum_unnecessary(skb) && 1395 __skb_checksum_complete(skb); 1396 } 1397 1398 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1399 enum skb_drop_reason *reason); 1400 1401 1402 int tcp_filter(struct sock *sk, struct sk_buff *skb); 1403 void tcp_set_state(struct sock *sk, int state); 1404 void tcp_done(struct sock *sk); 1405 int tcp_abort(struct sock *sk, int err); 1406 1407 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 1408 { 1409 rx_opt->dsack = 0; 1410 rx_opt->num_sacks = 0; 1411 } 1412 1413 void tcp_cwnd_restart(struct sock *sk, s32 delta); 1414 1415 static inline void tcp_slow_start_after_idle_check(struct sock *sk) 1416 { 1417 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; 1418 struct tcp_sock *tp = tcp_sk(sk); 1419 s32 delta; 1420 1421 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) || 1422 tp->packets_out || ca_ops->cong_control) 1423 return; 1424 delta = tcp_jiffies32 - tp->lsndtime; 1425 if (delta > inet_csk(sk)->icsk_rto) 1426 tcp_cwnd_restart(sk, delta); 1427 } 1428 1429 /* Determine a window scaling and initial window to offer. */ 1430 void tcp_select_initial_window(const struct sock *sk, int __space, 1431 __u32 mss, __u32 *rcv_wnd, 1432 __u32 *window_clamp, int wscale_ok, 1433 __u8 *rcv_wscale, __u32 init_rcv_wnd); 1434 1435 static inline int __tcp_win_from_space(u8 scaling_ratio, int space) 1436 { 1437 s64 scaled_space = (s64)space * scaling_ratio; 1438 1439 return scaled_space >> TCP_RMEM_TO_WIN_SCALE; 1440 } 1441 1442 static inline int tcp_win_from_space(const struct sock *sk, int space) 1443 { 1444 return __tcp_win_from_space(tcp_sk(sk)->scaling_ratio, space); 1445 } 1446 1447 /* inverse of __tcp_win_from_space() */ 1448 static inline int __tcp_space_from_win(u8 scaling_ratio, int win) 1449 { 1450 u64 val = (u64)win << TCP_RMEM_TO_WIN_SCALE; 1451 1452 do_div(val, scaling_ratio); 1453 return val; 1454 } 1455 1456 static inline int tcp_space_from_win(const struct sock *sk, int win) 1457 { 1458 return __tcp_space_from_win(tcp_sk(sk)->scaling_ratio, win); 1459 } 1460 1461 static inline void tcp_scaling_ratio_init(struct sock *sk) 1462 { 1463 /* Assume a conservative default of 1200 bytes of payload per 4K page. 1464 * This may be adjusted later in tcp_measure_rcv_mss(). 1465 */ 1466 tcp_sk(sk)->scaling_ratio = (1200 << TCP_RMEM_TO_WIN_SCALE) / 1467 SKB_TRUESIZE(4096); 1468 } 1469 1470 /* Note: caller must be prepared to deal with negative returns */ 1471 static inline int tcp_space(const struct sock *sk) 1472 { 1473 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - 1474 READ_ONCE(sk->sk_backlog.len) - 1475 atomic_read(&sk->sk_rmem_alloc)); 1476 } 1477 1478 static inline int tcp_full_space(const struct sock *sk) 1479 { 1480 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); 1481 } 1482 1483 static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) 1484 { 1485 int unused_mem = sk_unused_reserved_mem(sk); 1486 struct tcp_sock *tp = tcp_sk(sk); 1487 1488 tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss); 1489 if (unused_mem) 1490 tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh, 1491 tcp_win_from_space(sk, unused_mem)); 1492 } 1493 1494 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1495 void __tcp_cleanup_rbuf(struct sock *sk, int copied); 1496 1497 1498 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1499 * If 87.5 % (7/8) of the space has been consumed, we want to override 1500 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1501 * len/truesize ratio. 1502 */ 1503 static inline bool tcp_rmem_pressure(const struct sock *sk) 1504 { 1505 int rcvbuf, threshold; 1506 1507 if (tcp_under_memory_pressure(sk)) 1508 return true; 1509 1510 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1511 threshold = rcvbuf - (rcvbuf >> 3); 1512 1513 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1514 } 1515 1516 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1517 { 1518 const struct tcp_sock *tp = tcp_sk(sk); 1519 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1520 1521 if (avail <= 0) 1522 return false; 1523 1524 return (avail >= target) || tcp_rmem_pressure(sk) || 1525 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1526 } 1527 1528 extern void tcp_openreq_init_rwin(struct request_sock *req, 1529 const struct sock *sk_listener, 1530 const struct dst_entry *dst); 1531 1532 void tcp_enter_memory_pressure(struct sock *sk); 1533 void tcp_leave_memory_pressure(struct sock *sk); 1534 1535 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1536 { 1537 struct net *net = sock_net((struct sock *)tp); 1538 int val; 1539 1540 /* Paired with WRITE_ONCE() in tcp_sock_set_keepintvl() 1541 * and do_tcp_setsockopt(). 1542 */ 1543 val = READ_ONCE(tp->keepalive_intvl); 1544 1545 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); 1546 } 1547 1548 static inline int keepalive_time_when(const struct tcp_sock *tp) 1549 { 1550 struct net *net = sock_net((struct sock *)tp); 1551 int val; 1552 1553 /* Paired with WRITE_ONCE() in tcp_sock_set_keepidle_locked() */ 1554 val = READ_ONCE(tp->keepalive_time); 1555 1556 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); 1557 } 1558 1559 static inline int keepalive_probes(const struct tcp_sock *tp) 1560 { 1561 struct net *net = sock_net((struct sock *)tp); 1562 int val; 1563 1564 /* Paired with WRITE_ONCE() in tcp_sock_set_keepcnt() 1565 * and do_tcp_setsockopt(). 1566 */ 1567 val = READ_ONCE(tp->keepalive_probes); 1568 1569 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); 1570 } 1571 1572 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1573 { 1574 const struct inet_connection_sock *icsk = &tp->inet_conn; 1575 1576 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1577 tcp_jiffies32 - tp->rcv_tstamp); 1578 } 1579 1580 static inline int tcp_fin_time(const struct sock *sk) 1581 { 1582 int fin_timeout = tcp_sk(sk)->linger2 ? : 1583 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); 1584 const int rto = inet_csk(sk)->icsk_rto; 1585 1586 if (fin_timeout < (rto << 2) - (rto >> 1)) 1587 fin_timeout = (rto << 2) - (rto >> 1); 1588 1589 return fin_timeout; 1590 } 1591 1592 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1593 int paws_win) 1594 { 1595 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1596 return true; 1597 if (unlikely(!time_before32(ktime_get_seconds(), 1598 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1599 return true; 1600 /* 1601 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1602 * then following tcp messages have valid values. Ignore 0 value, 1603 * or else 'negative' tsval might forbid us to accept their packets. 1604 */ 1605 if (!rx_opt->ts_recent) 1606 return true; 1607 return false; 1608 } 1609 1610 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1611 int rst) 1612 { 1613 if (tcp_paws_check(rx_opt, 0)) 1614 return false; 1615 1616 /* RST segments are not recommended to carry timestamp, 1617 and, if they do, it is recommended to ignore PAWS because 1618 "their cleanup function should take precedence over timestamps." 1619 Certainly, it is mistake. It is necessary to understand the reasons 1620 of this constraint to relax it: if peer reboots, clock may go 1621 out-of-sync and half-open connections will not be reset. 1622 Actually, the problem would be not existing if all 1623 the implementations followed draft about maintaining clock 1624 via reboots. Linux-2.2 DOES NOT! 1625 1626 However, we can relax time bounds for RST segments to MSL. 1627 */ 1628 if (rst && !time_before32(ktime_get_seconds(), 1629 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1630 return false; 1631 return true; 1632 } 1633 1634 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1635 int mib_idx, u32 *last_oow_ack_time); 1636 1637 static inline void tcp_mib_init(struct net *net) 1638 { 1639 /* See RFC 2012 */ 1640 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1641 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1642 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1643 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1644 } 1645 1646 /* from STCP */ 1647 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1648 { 1649 tp->lost_skb_hint = NULL; 1650 } 1651 1652 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1653 { 1654 tcp_clear_retrans_hints_partial(tp); 1655 tp->retransmit_skb_hint = NULL; 1656 } 1657 1658 union tcp_md5_addr { 1659 struct in_addr a4; 1660 #if IS_ENABLED(CONFIG_IPV6) 1661 struct in6_addr a6; 1662 #endif 1663 }; 1664 1665 /* - key database */ 1666 struct tcp_md5sig_key { 1667 struct hlist_node node; 1668 u8 keylen; 1669 u8 family; /* AF_INET or AF_INET6 */ 1670 u8 prefixlen; 1671 u8 flags; 1672 union tcp_md5_addr addr; 1673 int l3index; /* set if key added with L3 scope */ 1674 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1675 struct rcu_head rcu; 1676 }; 1677 1678 /* - sock block */ 1679 struct tcp_md5sig_info { 1680 struct hlist_head head; 1681 struct rcu_head rcu; 1682 }; 1683 1684 /* - pseudo header */ 1685 struct tcp4_pseudohdr { 1686 __be32 saddr; 1687 __be32 daddr; 1688 __u8 pad; 1689 __u8 protocol; 1690 __be16 len; 1691 }; 1692 1693 struct tcp6_pseudohdr { 1694 struct in6_addr saddr; 1695 struct in6_addr daddr; 1696 __be32 len; 1697 __be32 protocol; /* including padding */ 1698 }; 1699 1700 union tcp_md5sum_block { 1701 struct tcp4_pseudohdr ip4; 1702 #if IS_ENABLED(CONFIG_IPV6) 1703 struct tcp6_pseudohdr ip6; 1704 #endif 1705 }; 1706 1707 /* - pool: digest algorithm, hash description and scratch buffer */ 1708 struct tcp_md5sig_pool { 1709 struct ahash_request *md5_req; 1710 void *scratch; 1711 }; 1712 1713 /* - functions */ 1714 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1715 const struct sock *sk, const struct sk_buff *skb); 1716 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1717 int family, u8 prefixlen, int l3index, u8 flags, 1718 const u8 *newkey, u8 newkeylen); 1719 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1720 int family, u8 prefixlen, int l3index, 1721 struct tcp_md5sig_key *key); 1722 1723 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1724 int family, u8 prefixlen, int l3index, u8 flags); 1725 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1726 const struct sock *addr_sk); 1727 1728 #ifdef CONFIG_TCP_MD5SIG 1729 #include <linux/jump_label.h> 1730 extern struct static_key_false_deferred tcp_md5_needed; 1731 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1732 const union tcp_md5_addr *addr, 1733 int family); 1734 static inline struct tcp_md5sig_key * 1735 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1736 const union tcp_md5_addr *addr, int family) 1737 { 1738 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1739 return NULL; 1740 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1741 } 1742 1743 enum skb_drop_reason 1744 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1745 const void *saddr, const void *daddr, 1746 int family, int dif, int sdif); 1747 1748 1749 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1750 #else 1751 static inline struct tcp_md5sig_key * 1752 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1753 const union tcp_md5_addr *addr, int family) 1754 { 1755 return NULL; 1756 } 1757 1758 static inline enum skb_drop_reason 1759 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1760 const void *saddr, const void *daddr, 1761 int family, int dif, int sdif) 1762 { 1763 return SKB_NOT_DROPPED_YET; 1764 } 1765 #define tcp_twsk_md5_key(twsk) NULL 1766 #endif 1767 1768 bool tcp_alloc_md5sig_pool(void); 1769 1770 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1771 static inline void tcp_put_md5sig_pool(void) 1772 { 1773 local_bh_enable(); 1774 } 1775 1776 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1777 unsigned int header_len); 1778 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1779 const struct tcp_md5sig_key *key); 1780 1781 /* From tcp_fastopen.c */ 1782 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1783 struct tcp_fastopen_cookie *cookie); 1784 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1785 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1786 u16 try_exp); 1787 struct tcp_fastopen_request { 1788 /* Fast Open cookie. Size 0 means a cookie request */ 1789 struct tcp_fastopen_cookie cookie; 1790 struct msghdr *data; /* data in MSG_FASTOPEN */ 1791 size_t size; 1792 int copied; /* queued in tcp_connect() */ 1793 struct ubuf_info *uarg; 1794 }; 1795 void tcp_free_fastopen_req(struct tcp_sock *tp); 1796 void tcp_fastopen_destroy_cipher(struct sock *sk); 1797 void tcp_fastopen_ctx_destroy(struct net *net); 1798 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1799 void *primary_key, void *backup_key); 1800 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1801 u64 *key); 1802 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1803 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1804 struct request_sock *req, 1805 struct tcp_fastopen_cookie *foc, 1806 const struct dst_entry *dst); 1807 void tcp_fastopen_init_key_once(struct net *net); 1808 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1809 struct tcp_fastopen_cookie *cookie); 1810 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1811 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1812 #define TCP_FASTOPEN_KEY_MAX 2 1813 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1814 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1815 1816 /* Fastopen key context */ 1817 struct tcp_fastopen_context { 1818 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1819 int num; 1820 struct rcu_head rcu; 1821 }; 1822 1823 void tcp_fastopen_active_disable(struct sock *sk); 1824 bool tcp_fastopen_active_should_disable(struct sock *sk); 1825 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1826 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1827 1828 /* Caller needs to wrap with rcu_read_(un)lock() */ 1829 static inline 1830 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1831 { 1832 struct tcp_fastopen_context *ctx; 1833 1834 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1835 if (!ctx) 1836 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1837 return ctx; 1838 } 1839 1840 static inline 1841 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1842 const struct tcp_fastopen_cookie *orig) 1843 { 1844 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1845 orig->len == foc->len && 1846 !memcmp(orig->val, foc->val, foc->len)) 1847 return true; 1848 return false; 1849 } 1850 1851 static inline 1852 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1853 { 1854 return ctx->num; 1855 } 1856 1857 /* Latencies incurred by various limits for a sender. They are 1858 * chronograph-like stats that are mutually exclusive. 1859 */ 1860 enum tcp_chrono { 1861 TCP_CHRONO_UNSPEC, 1862 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1863 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1864 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1865 __TCP_CHRONO_MAX, 1866 }; 1867 1868 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1869 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1870 1871 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1872 * the same memory storage than skb->destructor/_skb_refdst 1873 */ 1874 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1875 { 1876 skb->destructor = NULL; 1877 skb->_skb_refdst = 0UL; 1878 } 1879 1880 #define tcp_skb_tsorted_save(skb) { \ 1881 unsigned long _save = skb->_skb_refdst; \ 1882 skb->_skb_refdst = 0UL; 1883 1884 #define tcp_skb_tsorted_restore(skb) \ 1885 skb->_skb_refdst = _save; \ 1886 } 1887 1888 void tcp_write_queue_purge(struct sock *sk); 1889 1890 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1891 { 1892 return skb_rb_first(&sk->tcp_rtx_queue); 1893 } 1894 1895 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1896 { 1897 return skb_rb_last(&sk->tcp_rtx_queue); 1898 } 1899 1900 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1901 { 1902 return skb_peek_tail(&sk->sk_write_queue); 1903 } 1904 1905 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1906 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1907 1908 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1909 { 1910 return skb_peek(&sk->sk_write_queue); 1911 } 1912 1913 static inline bool tcp_skb_is_last(const struct sock *sk, 1914 const struct sk_buff *skb) 1915 { 1916 return skb_queue_is_last(&sk->sk_write_queue, skb); 1917 } 1918 1919 /** 1920 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1921 * @sk: socket 1922 * 1923 * Since the write queue can have a temporary empty skb in it, 1924 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1925 */ 1926 static inline bool tcp_write_queue_empty(const struct sock *sk) 1927 { 1928 const struct tcp_sock *tp = tcp_sk(sk); 1929 1930 return tp->write_seq == tp->snd_nxt; 1931 } 1932 1933 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1934 { 1935 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1936 } 1937 1938 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1939 { 1940 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1941 } 1942 1943 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1944 { 1945 __skb_queue_tail(&sk->sk_write_queue, skb); 1946 1947 /* Queue it, remembering where we must start sending. */ 1948 if (sk->sk_write_queue.next == skb) 1949 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1950 } 1951 1952 /* Insert new before skb on the write queue of sk. */ 1953 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1954 struct sk_buff *skb, 1955 struct sock *sk) 1956 { 1957 __skb_queue_before(&sk->sk_write_queue, skb, new); 1958 } 1959 1960 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1961 { 1962 tcp_skb_tsorted_anchor_cleanup(skb); 1963 __skb_unlink(skb, &sk->sk_write_queue); 1964 } 1965 1966 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1967 1968 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1969 { 1970 tcp_skb_tsorted_anchor_cleanup(skb); 1971 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1972 } 1973 1974 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1975 { 1976 list_del(&skb->tcp_tsorted_anchor); 1977 tcp_rtx_queue_unlink(skb, sk); 1978 tcp_wmem_free_skb(sk, skb); 1979 } 1980 1981 static inline void tcp_push_pending_frames(struct sock *sk) 1982 { 1983 if (tcp_send_head(sk)) { 1984 struct tcp_sock *tp = tcp_sk(sk); 1985 1986 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1987 } 1988 } 1989 1990 /* Start sequence of the skb just after the highest skb with SACKed 1991 * bit, valid only if sacked_out > 0 or when the caller has ensured 1992 * validity by itself. 1993 */ 1994 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1995 { 1996 if (!tp->sacked_out) 1997 return tp->snd_una; 1998 1999 if (tp->highest_sack == NULL) 2000 return tp->snd_nxt; 2001 2002 return TCP_SKB_CB(tp->highest_sack)->seq; 2003 } 2004 2005 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 2006 { 2007 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 2008 } 2009 2010 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 2011 { 2012 return tcp_sk(sk)->highest_sack; 2013 } 2014 2015 static inline void tcp_highest_sack_reset(struct sock *sk) 2016 { 2017 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 2018 } 2019 2020 /* Called when old skb is about to be deleted and replaced by new skb */ 2021 static inline void tcp_highest_sack_replace(struct sock *sk, 2022 struct sk_buff *old, 2023 struct sk_buff *new) 2024 { 2025 if (old == tcp_highest_sack(sk)) 2026 tcp_sk(sk)->highest_sack = new; 2027 } 2028 2029 /* This helper checks if socket has IP_TRANSPARENT set */ 2030 static inline bool inet_sk_transparent(const struct sock *sk) 2031 { 2032 switch (sk->sk_state) { 2033 case TCP_TIME_WAIT: 2034 return inet_twsk(sk)->tw_transparent; 2035 case TCP_NEW_SYN_RECV: 2036 return inet_rsk(inet_reqsk(sk))->no_srccheck; 2037 } 2038 return inet_test_bit(TRANSPARENT, sk); 2039 } 2040 2041 /* Determines whether this is a thin stream (which may suffer from 2042 * increased latency). Used to trigger latency-reducing mechanisms. 2043 */ 2044 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 2045 { 2046 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 2047 } 2048 2049 /* /proc */ 2050 enum tcp_seq_states { 2051 TCP_SEQ_STATE_LISTENING, 2052 TCP_SEQ_STATE_ESTABLISHED, 2053 }; 2054 2055 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 2056 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 2057 void tcp_seq_stop(struct seq_file *seq, void *v); 2058 2059 struct tcp_seq_afinfo { 2060 sa_family_t family; 2061 }; 2062 2063 struct tcp_iter_state { 2064 struct seq_net_private p; 2065 enum tcp_seq_states state; 2066 struct sock *syn_wait_sk; 2067 int bucket, offset, sbucket, num; 2068 loff_t last_pos; 2069 }; 2070 2071 extern struct request_sock_ops tcp_request_sock_ops; 2072 extern struct request_sock_ops tcp6_request_sock_ops; 2073 2074 void tcp_v4_destroy_sock(struct sock *sk); 2075 2076 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 2077 netdev_features_t features); 2078 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 2079 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 2080 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 2081 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 2082 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 2083 void tcp_gro_complete(struct sk_buff *skb); 2084 2085 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 2086 2087 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 2088 { 2089 struct net *net = sock_net((struct sock *)tp); 2090 u32 val; 2091 2092 val = READ_ONCE(tp->notsent_lowat); 2093 2094 return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); 2095 } 2096 2097 bool tcp_stream_memory_free(const struct sock *sk, int wake); 2098 2099 #ifdef CONFIG_PROC_FS 2100 int tcp4_proc_init(void); 2101 void tcp4_proc_exit(void); 2102 #endif 2103 2104 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2105 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2106 const struct tcp_request_sock_ops *af_ops, 2107 struct sock *sk, struct sk_buff *skb); 2108 2109 /* TCP af-specific functions */ 2110 struct tcp_sock_af_ops { 2111 #ifdef CONFIG_TCP_MD5SIG 2112 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2113 const struct sock *addr_sk); 2114 int (*calc_md5_hash)(char *location, 2115 const struct tcp_md5sig_key *md5, 2116 const struct sock *sk, 2117 const struct sk_buff *skb); 2118 int (*md5_parse)(struct sock *sk, 2119 int optname, 2120 sockptr_t optval, 2121 int optlen); 2122 #endif 2123 }; 2124 2125 struct tcp_request_sock_ops { 2126 u16 mss_clamp; 2127 #ifdef CONFIG_TCP_MD5SIG 2128 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2129 const struct sock *addr_sk); 2130 int (*calc_md5_hash) (char *location, 2131 const struct tcp_md5sig_key *md5, 2132 const struct sock *sk, 2133 const struct sk_buff *skb); 2134 #endif 2135 #ifdef CONFIG_SYN_COOKIES 2136 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2137 __u16 *mss); 2138 #endif 2139 struct dst_entry *(*route_req)(const struct sock *sk, 2140 struct sk_buff *skb, 2141 struct flowi *fl, 2142 struct request_sock *req); 2143 u32 (*init_seq)(const struct sk_buff *skb); 2144 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2145 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2146 struct flowi *fl, struct request_sock *req, 2147 struct tcp_fastopen_cookie *foc, 2148 enum tcp_synack_type synack_type, 2149 struct sk_buff *syn_skb); 2150 }; 2151 2152 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2153 #if IS_ENABLED(CONFIG_IPV6) 2154 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2155 #endif 2156 2157 #ifdef CONFIG_SYN_COOKIES 2158 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2159 const struct sock *sk, struct sk_buff *skb, 2160 __u16 *mss) 2161 { 2162 tcp_synq_overflow(sk); 2163 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2164 return ops->cookie_init_seq(skb, mss); 2165 } 2166 #else 2167 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2168 const struct sock *sk, struct sk_buff *skb, 2169 __u16 *mss) 2170 { 2171 return 0; 2172 } 2173 #endif 2174 2175 int tcpv4_offload_init(void); 2176 2177 void tcp_v4_init(void); 2178 void tcp_init(void); 2179 2180 /* tcp_recovery.c */ 2181 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2182 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2183 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2184 u32 reo_wnd); 2185 extern bool tcp_rack_mark_lost(struct sock *sk); 2186 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2187 u64 xmit_time); 2188 extern void tcp_rack_reo_timeout(struct sock *sk); 2189 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2190 2191 /* tcp_plb.c */ 2192 2193 /* 2194 * Scaling factor for fractions in PLB. For example, tcp_plb_update_state 2195 * expects cong_ratio which represents fraction of traffic that experienced 2196 * congestion over a single RTT. In order to avoid floating point operations, 2197 * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in. 2198 */ 2199 #define TCP_PLB_SCALE 8 2200 2201 /* State for PLB (Protective Load Balancing) for a single TCP connection. */ 2202 struct tcp_plb_state { 2203 u8 consec_cong_rounds:5, /* consecutive congested rounds */ 2204 unused:3; 2205 u32 pause_until; /* jiffies32 when PLB can resume rerouting */ 2206 }; 2207 2208 static inline void tcp_plb_init(const struct sock *sk, 2209 struct tcp_plb_state *plb) 2210 { 2211 plb->consec_cong_rounds = 0; 2212 plb->pause_until = 0; 2213 } 2214 void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb, 2215 const int cong_ratio); 2216 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb); 2217 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb); 2218 2219 /* At how many usecs into the future should the RTO fire? */ 2220 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2221 { 2222 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2223 u32 rto = inet_csk(sk)->icsk_rto; 2224 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2225 2226 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2227 } 2228 2229 /* 2230 * Save and compile IPv4 options, return a pointer to it 2231 */ 2232 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2233 struct sk_buff *skb) 2234 { 2235 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2236 struct ip_options_rcu *dopt = NULL; 2237 2238 if (opt->optlen) { 2239 int opt_size = sizeof(*dopt) + opt->optlen; 2240 2241 dopt = kmalloc(opt_size, GFP_ATOMIC); 2242 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2243 kfree(dopt); 2244 dopt = NULL; 2245 } 2246 } 2247 return dopt; 2248 } 2249 2250 /* locally generated TCP pure ACKs have skb->truesize == 2 2251 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2252 * This is much faster than dissecting the packet to find out. 2253 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2254 */ 2255 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2256 { 2257 return skb->truesize == 2; 2258 } 2259 2260 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2261 { 2262 skb->truesize = 2; 2263 } 2264 2265 static inline int tcp_inq(struct sock *sk) 2266 { 2267 struct tcp_sock *tp = tcp_sk(sk); 2268 int answ; 2269 2270 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2271 answ = 0; 2272 } else if (sock_flag(sk, SOCK_URGINLINE) || 2273 !tp->urg_data || 2274 before(tp->urg_seq, tp->copied_seq) || 2275 !before(tp->urg_seq, tp->rcv_nxt)) { 2276 2277 answ = tp->rcv_nxt - tp->copied_seq; 2278 2279 /* Subtract 1, if FIN was received */ 2280 if (answ && sock_flag(sk, SOCK_DONE)) 2281 answ--; 2282 } else { 2283 answ = tp->urg_seq - tp->copied_seq; 2284 } 2285 2286 return answ; 2287 } 2288 2289 int tcp_peek_len(struct socket *sock); 2290 2291 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2292 { 2293 u16 segs_in; 2294 2295 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2296 2297 /* We update these fields while other threads might 2298 * read them from tcp_get_info() 2299 */ 2300 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2301 if (skb->len > tcp_hdrlen(skb)) 2302 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2303 } 2304 2305 /* 2306 * TCP listen path runs lockless. 2307 * We forced "struct sock" to be const qualified to make sure 2308 * we don't modify one of its field by mistake. 2309 * Here, we increment sk_drops which is an atomic_t, so we can safely 2310 * make sock writable again. 2311 */ 2312 static inline void tcp_listendrop(const struct sock *sk) 2313 { 2314 atomic_inc(&((struct sock *)sk)->sk_drops); 2315 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2316 } 2317 2318 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2319 2320 /* 2321 * Interface for adding Upper Level Protocols over TCP 2322 */ 2323 2324 #define TCP_ULP_NAME_MAX 16 2325 #define TCP_ULP_MAX 128 2326 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2327 2328 struct tcp_ulp_ops { 2329 struct list_head list; 2330 2331 /* initialize ulp */ 2332 int (*init)(struct sock *sk); 2333 /* update ulp */ 2334 void (*update)(struct sock *sk, struct proto *p, 2335 void (*write_space)(struct sock *sk)); 2336 /* cleanup ulp */ 2337 void (*release)(struct sock *sk); 2338 /* diagnostic */ 2339 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2340 size_t (*get_info_size)(const struct sock *sk); 2341 /* clone ulp */ 2342 void (*clone)(const struct request_sock *req, struct sock *newsk, 2343 const gfp_t priority); 2344 2345 char name[TCP_ULP_NAME_MAX]; 2346 struct module *owner; 2347 }; 2348 int tcp_register_ulp(struct tcp_ulp_ops *type); 2349 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2350 int tcp_set_ulp(struct sock *sk, const char *name); 2351 void tcp_get_available_ulp(char *buf, size_t len); 2352 void tcp_cleanup_ulp(struct sock *sk); 2353 void tcp_update_ulp(struct sock *sk, struct proto *p, 2354 void (*write_space)(struct sock *sk)); 2355 2356 #define MODULE_ALIAS_TCP_ULP(name) \ 2357 __MODULE_INFO(alias, alias_userspace, name); \ 2358 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2359 2360 #ifdef CONFIG_NET_SOCK_MSG 2361 struct sk_msg; 2362 struct sk_psock; 2363 2364 #ifdef CONFIG_BPF_SYSCALL 2365 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2366 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2367 #endif /* CONFIG_BPF_SYSCALL */ 2368 2369 #ifdef CONFIG_INET 2370 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); 2371 #else 2372 static inline void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) 2373 { 2374 } 2375 #endif 2376 2377 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 2378 struct sk_msg *msg, u32 bytes, int flags); 2379 #endif /* CONFIG_NET_SOCK_MSG */ 2380 2381 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2382 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2383 { 2384 } 2385 #endif 2386 2387 #ifdef CONFIG_CGROUP_BPF 2388 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2389 struct sk_buff *skb, 2390 unsigned int end_offset) 2391 { 2392 skops->skb = skb; 2393 skops->skb_data_end = skb->data + end_offset; 2394 } 2395 #else 2396 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2397 struct sk_buff *skb, 2398 unsigned int end_offset) 2399 { 2400 } 2401 #endif 2402 2403 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2404 * is < 0, then the BPF op failed (for example if the loaded BPF 2405 * program does not support the chosen operation or there is no BPF 2406 * program loaded). 2407 */ 2408 #ifdef CONFIG_BPF 2409 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2410 { 2411 struct bpf_sock_ops_kern sock_ops; 2412 int ret; 2413 2414 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2415 if (sk_fullsock(sk)) { 2416 sock_ops.is_fullsock = 1; 2417 sock_owned_by_me(sk); 2418 } 2419 2420 sock_ops.sk = sk; 2421 sock_ops.op = op; 2422 if (nargs > 0) 2423 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2424 2425 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2426 if (ret == 0) 2427 ret = sock_ops.reply; 2428 else 2429 ret = -1; 2430 return ret; 2431 } 2432 2433 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2434 { 2435 u32 args[2] = {arg1, arg2}; 2436 2437 return tcp_call_bpf(sk, op, 2, args); 2438 } 2439 2440 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2441 u32 arg3) 2442 { 2443 u32 args[3] = {arg1, arg2, arg3}; 2444 2445 return tcp_call_bpf(sk, op, 3, args); 2446 } 2447 2448 #else 2449 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2450 { 2451 return -EPERM; 2452 } 2453 2454 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2455 { 2456 return -EPERM; 2457 } 2458 2459 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2460 u32 arg3) 2461 { 2462 return -EPERM; 2463 } 2464 2465 #endif 2466 2467 static inline u32 tcp_timeout_init(struct sock *sk) 2468 { 2469 int timeout; 2470 2471 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2472 2473 if (timeout <= 0) 2474 timeout = TCP_TIMEOUT_INIT; 2475 return min_t(int, timeout, TCP_RTO_MAX); 2476 } 2477 2478 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2479 { 2480 int rwnd; 2481 2482 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2483 2484 if (rwnd < 0) 2485 rwnd = 0; 2486 return rwnd; 2487 } 2488 2489 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2490 { 2491 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2492 } 2493 2494 static inline void tcp_bpf_rtt(struct sock *sk) 2495 { 2496 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2497 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2498 } 2499 2500 #if IS_ENABLED(CONFIG_SMC) 2501 extern struct static_key_false tcp_have_smc; 2502 #endif 2503 2504 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2505 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2506 void (*cad)(struct sock *sk, u32 ack_seq)); 2507 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2508 void clean_acked_data_flush(void); 2509 #endif 2510 2511 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2512 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2513 const struct tcp_sock *tp) 2514 { 2515 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2516 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2517 } 2518 2519 /* Compute Earliest Departure Time for some control packets 2520 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2521 */ 2522 static inline u64 tcp_transmit_time(const struct sock *sk) 2523 { 2524 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2525 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2526 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2527 2528 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2529 } 2530 return 0; 2531 } 2532 2533 #endif /* _TCP_H */ 2534