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 u64 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, u32 new_ssthresh) 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, new_ssthresh); 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 static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) 1495 { 1496 __tcp_adjust_rcv_ssthresh(sk, 4U * tcp_sk(sk)->advmss); 1497 } 1498 1499 void tcp_cleanup_rbuf(struct sock *sk, int copied); 1500 void __tcp_cleanup_rbuf(struct sock *sk, int copied); 1501 1502 1503 /* We provision sk_rcvbuf around 200% of sk_rcvlowat. 1504 * If 87.5 % (7/8) of the space has been consumed, we want to override 1505 * SO_RCVLOWAT constraint, since we are receiving skbs with too small 1506 * len/truesize ratio. 1507 */ 1508 static inline bool tcp_rmem_pressure(const struct sock *sk) 1509 { 1510 int rcvbuf, threshold; 1511 1512 if (tcp_under_memory_pressure(sk)) 1513 return true; 1514 1515 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1516 threshold = rcvbuf - (rcvbuf >> 3); 1517 1518 return atomic_read(&sk->sk_rmem_alloc) > threshold; 1519 } 1520 1521 static inline bool tcp_epollin_ready(const struct sock *sk, int target) 1522 { 1523 const struct tcp_sock *tp = tcp_sk(sk); 1524 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); 1525 1526 if (avail <= 0) 1527 return false; 1528 1529 return (avail >= target) || tcp_rmem_pressure(sk) || 1530 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); 1531 } 1532 1533 extern void tcp_openreq_init_rwin(struct request_sock *req, 1534 const struct sock *sk_listener, 1535 const struct dst_entry *dst); 1536 1537 void tcp_enter_memory_pressure(struct sock *sk); 1538 void tcp_leave_memory_pressure(struct sock *sk); 1539 1540 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1541 { 1542 struct net *net = sock_net((struct sock *)tp); 1543 int val; 1544 1545 /* Paired with WRITE_ONCE() in tcp_sock_set_keepintvl() 1546 * and do_tcp_setsockopt(). 1547 */ 1548 val = READ_ONCE(tp->keepalive_intvl); 1549 1550 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); 1551 } 1552 1553 static inline int keepalive_time_when(const struct tcp_sock *tp) 1554 { 1555 struct net *net = sock_net((struct sock *)tp); 1556 int val; 1557 1558 /* Paired with WRITE_ONCE() in tcp_sock_set_keepidle_locked() */ 1559 val = READ_ONCE(tp->keepalive_time); 1560 1561 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); 1562 } 1563 1564 static inline int keepalive_probes(const struct tcp_sock *tp) 1565 { 1566 struct net *net = sock_net((struct sock *)tp); 1567 int val; 1568 1569 /* Paired with WRITE_ONCE() in tcp_sock_set_keepcnt() 1570 * and do_tcp_setsockopt(). 1571 */ 1572 val = READ_ONCE(tp->keepalive_probes); 1573 1574 return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); 1575 } 1576 1577 static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) 1578 { 1579 const struct inet_connection_sock *icsk = &tp->inet_conn; 1580 1581 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime, 1582 tcp_jiffies32 - tp->rcv_tstamp); 1583 } 1584 1585 static inline int tcp_fin_time(const struct sock *sk) 1586 { 1587 int fin_timeout = tcp_sk(sk)->linger2 ? : 1588 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout); 1589 const int rto = inet_csk(sk)->icsk_rto; 1590 1591 if (fin_timeout < (rto << 2) - (rto >> 1)) 1592 fin_timeout = (rto << 2) - (rto >> 1); 1593 1594 return fin_timeout; 1595 } 1596 1597 static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, 1598 int paws_win) 1599 { 1600 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1601 return true; 1602 if (unlikely(!time_before32(ktime_get_seconds(), 1603 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) 1604 return true; 1605 /* 1606 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, 1607 * then following tcp messages have valid values. Ignore 0 value, 1608 * or else 'negative' tsval might forbid us to accept their packets. 1609 */ 1610 if (!rx_opt->ts_recent) 1611 return true; 1612 return false; 1613 } 1614 1615 static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt, 1616 int rst) 1617 { 1618 if (tcp_paws_check(rx_opt, 0)) 1619 return false; 1620 1621 /* RST segments are not recommended to carry timestamp, 1622 and, if they do, it is recommended to ignore PAWS because 1623 "their cleanup function should take precedence over timestamps." 1624 Certainly, it is mistake. It is necessary to understand the reasons 1625 of this constraint to relax it: if peer reboots, clock may go 1626 out-of-sync and half-open connections will not be reset. 1627 Actually, the problem would be not existing if all 1628 the implementations followed draft about maintaining clock 1629 via reboots. Linux-2.2 DOES NOT! 1630 1631 However, we can relax time bounds for RST segments to MSL. 1632 */ 1633 if (rst && !time_before32(ktime_get_seconds(), 1634 rx_opt->ts_recent_stamp + TCP_PAWS_MSL)) 1635 return false; 1636 return true; 1637 } 1638 1639 bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, 1640 int mib_idx, u32 *last_oow_ack_time); 1641 1642 static inline void tcp_mib_init(struct net *net) 1643 { 1644 /* See RFC 2012 */ 1645 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1); 1646 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1647 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1648 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1); 1649 } 1650 1651 /* from STCP */ 1652 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1653 { 1654 tp->lost_skb_hint = NULL; 1655 } 1656 1657 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1658 { 1659 tcp_clear_retrans_hints_partial(tp); 1660 tp->retransmit_skb_hint = NULL; 1661 } 1662 1663 union tcp_md5_addr { 1664 struct in_addr a4; 1665 #if IS_ENABLED(CONFIG_IPV6) 1666 struct in6_addr a6; 1667 #endif 1668 }; 1669 1670 /* - key database */ 1671 struct tcp_md5sig_key { 1672 struct hlist_node node; 1673 u8 keylen; 1674 u8 family; /* AF_INET or AF_INET6 */ 1675 u8 prefixlen; 1676 u8 flags; 1677 union tcp_md5_addr addr; 1678 int l3index; /* set if key added with L3 scope */ 1679 u8 key[TCP_MD5SIG_MAXKEYLEN]; 1680 struct rcu_head rcu; 1681 }; 1682 1683 /* - sock block */ 1684 struct tcp_md5sig_info { 1685 struct hlist_head head; 1686 struct rcu_head rcu; 1687 }; 1688 1689 /* - pseudo header */ 1690 struct tcp4_pseudohdr { 1691 __be32 saddr; 1692 __be32 daddr; 1693 __u8 pad; 1694 __u8 protocol; 1695 __be16 len; 1696 }; 1697 1698 struct tcp6_pseudohdr { 1699 struct in6_addr saddr; 1700 struct in6_addr daddr; 1701 __be32 len; 1702 __be32 protocol; /* including padding */ 1703 }; 1704 1705 union tcp_md5sum_block { 1706 struct tcp4_pseudohdr ip4; 1707 #if IS_ENABLED(CONFIG_IPV6) 1708 struct tcp6_pseudohdr ip6; 1709 #endif 1710 }; 1711 1712 /* - pool: digest algorithm, hash description and scratch buffer */ 1713 struct tcp_md5sig_pool { 1714 struct ahash_request *md5_req; 1715 void *scratch; 1716 }; 1717 1718 /* - functions */ 1719 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1720 const struct sock *sk, const struct sk_buff *skb); 1721 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1722 int family, u8 prefixlen, int l3index, u8 flags, 1723 const u8 *newkey, u8 newkeylen); 1724 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1725 int family, u8 prefixlen, int l3index, 1726 struct tcp_md5sig_key *key); 1727 1728 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, 1729 int family, u8 prefixlen, int l3index, u8 flags); 1730 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1731 const struct sock *addr_sk); 1732 1733 #ifdef CONFIG_TCP_MD5SIG 1734 #include <linux/jump_label.h> 1735 extern struct static_key_false_deferred tcp_md5_needed; 1736 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1737 const union tcp_md5_addr *addr, 1738 int family); 1739 static inline struct tcp_md5sig_key * 1740 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1741 const union tcp_md5_addr *addr, int family) 1742 { 1743 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1744 return NULL; 1745 return __tcp_md5_do_lookup(sk, l3index, addr, family); 1746 } 1747 1748 enum skb_drop_reason 1749 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1750 const void *saddr, const void *daddr, 1751 int family, int dif, int sdif); 1752 1753 1754 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 1755 #else 1756 static inline struct tcp_md5sig_key * 1757 tcp_md5_do_lookup(const struct sock *sk, int l3index, 1758 const union tcp_md5_addr *addr, int family) 1759 { 1760 return NULL; 1761 } 1762 1763 static inline enum skb_drop_reason 1764 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, 1765 const void *saddr, const void *daddr, 1766 int family, int dif, int sdif) 1767 { 1768 return SKB_NOT_DROPPED_YET; 1769 } 1770 #define tcp_twsk_md5_key(twsk) NULL 1771 #endif 1772 1773 bool tcp_alloc_md5sig_pool(void); 1774 1775 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); 1776 static inline void tcp_put_md5sig_pool(void) 1777 { 1778 local_bh_enable(); 1779 } 1780 1781 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, 1782 unsigned int header_len); 1783 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1784 const struct tcp_md5sig_key *key); 1785 1786 /* From tcp_fastopen.c */ 1787 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 1788 struct tcp_fastopen_cookie *cookie); 1789 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 1790 struct tcp_fastopen_cookie *cookie, bool syn_lost, 1791 u16 try_exp); 1792 struct tcp_fastopen_request { 1793 /* Fast Open cookie. Size 0 means a cookie request */ 1794 struct tcp_fastopen_cookie cookie; 1795 struct msghdr *data; /* data in MSG_FASTOPEN */ 1796 size_t size; 1797 int copied; /* queued in tcp_connect() */ 1798 struct ubuf_info *uarg; 1799 }; 1800 void tcp_free_fastopen_req(struct tcp_sock *tp); 1801 void tcp_fastopen_destroy_cipher(struct sock *sk); 1802 void tcp_fastopen_ctx_destroy(struct net *net); 1803 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk, 1804 void *primary_key, void *backup_key); 1805 int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk, 1806 u64 *key); 1807 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb); 1808 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, 1809 struct request_sock *req, 1810 struct tcp_fastopen_cookie *foc, 1811 const struct dst_entry *dst); 1812 void tcp_fastopen_init_key_once(struct net *net); 1813 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, 1814 struct tcp_fastopen_cookie *cookie); 1815 bool tcp_fastopen_defer_connect(struct sock *sk, int *err); 1816 #define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t) 1817 #define TCP_FASTOPEN_KEY_MAX 2 1818 #define TCP_FASTOPEN_KEY_BUF_LENGTH \ 1819 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX) 1820 1821 /* Fastopen key context */ 1822 struct tcp_fastopen_context { 1823 siphash_key_t key[TCP_FASTOPEN_KEY_MAX]; 1824 int num; 1825 struct rcu_head rcu; 1826 }; 1827 1828 void tcp_fastopen_active_disable(struct sock *sk); 1829 bool tcp_fastopen_active_should_disable(struct sock *sk); 1830 void tcp_fastopen_active_disable_ofo_check(struct sock *sk); 1831 void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired); 1832 1833 /* Caller needs to wrap with rcu_read_(un)lock() */ 1834 static inline 1835 struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk) 1836 { 1837 struct tcp_fastopen_context *ctx; 1838 1839 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx); 1840 if (!ctx) 1841 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx); 1842 return ctx; 1843 } 1844 1845 static inline 1846 bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc, 1847 const struct tcp_fastopen_cookie *orig) 1848 { 1849 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE && 1850 orig->len == foc->len && 1851 !memcmp(orig->val, foc->val, foc->len)) 1852 return true; 1853 return false; 1854 } 1855 1856 static inline 1857 int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx) 1858 { 1859 return ctx->num; 1860 } 1861 1862 /* Latencies incurred by various limits for a sender. They are 1863 * chronograph-like stats that are mutually exclusive. 1864 */ 1865 enum tcp_chrono { 1866 TCP_CHRONO_UNSPEC, 1867 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */ 1868 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */ 1869 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */ 1870 __TCP_CHRONO_MAX, 1871 }; 1872 1873 void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type); 1874 void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type); 1875 1876 /* This helper is needed, because skb->tcp_tsorted_anchor uses 1877 * the same memory storage than skb->destructor/_skb_refdst 1878 */ 1879 static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb) 1880 { 1881 skb->destructor = NULL; 1882 skb->_skb_refdst = 0UL; 1883 } 1884 1885 #define tcp_skb_tsorted_save(skb) { \ 1886 unsigned long _save = skb->_skb_refdst; \ 1887 skb->_skb_refdst = 0UL; 1888 1889 #define tcp_skb_tsorted_restore(skb) \ 1890 skb->_skb_refdst = _save; \ 1891 } 1892 1893 void tcp_write_queue_purge(struct sock *sk); 1894 1895 static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) 1896 { 1897 return skb_rb_first(&sk->tcp_rtx_queue); 1898 } 1899 1900 static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) 1901 { 1902 return skb_rb_last(&sk->tcp_rtx_queue); 1903 } 1904 1905 static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk) 1906 { 1907 return skb_peek_tail(&sk->sk_write_queue); 1908 } 1909 1910 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1911 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1912 1913 static inline struct sk_buff *tcp_send_head(const struct sock *sk) 1914 { 1915 return skb_peek(&sk->sk_write_queue); 1916 } 1917 1918 static inline bool tcp_skb_is_last(const struct sock *sk, 1919 const struct sk_buff *skb) 1920 { 1921 return skb_queue_is_last(&sk->sk_write_queue, skb); 1922 } 1923 1924 /** 1925 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue 1926 * @sk: socket 1927 * 1928 * Since the write queue can have a temporary empty skb in it, 1929 * we must not use "return skb_queue_empty(&sk->sk_write_queue)" 1930 */ 1931 static inline bool tcp_write_queue_empty(const struct sock *sk) 1932 { 1933 const struct tcp_sock *tp = tcp_sk(sk); 1934 1935 return tp->write_seq == tp->snd_nxt; 1936 } 1937 1938 static inline bool tcp_rtx_queue_empty(const struct sock *sk) 1939 { 1940 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue); 1941 } 1942 1943 static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk) 1944 { 1945 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk); 1946 } 1947 1948 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1949 { 1950 __skb_queue_tail(&sk->sk_write_queue, skb); 1951 1952 /* Queue it, remembering where we must start sending. */ 1953 if (sk->sk_write_queue.next == skb) 1954 tcp_chrono_start(sk, TCP_CHRONO_BUSY); 1955 } 1956 1957 /* Insert new before skb on the write queue of sk. */ 1958 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1959 struct sk_buff *skb, 1960 struct sock *sk) 1961 { 1962 __skb_queue_before(&sk->sk_write_queue, skb, new); 1963 } 1964 1965 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1966 { 1967 tcp_skb_tsorted_anchor_cleanup(skb); 1968 __skb_unlink(skb, &sk->sk_write_queue); 1969 } 1970 1971 void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb); 1972 1973 static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk) 1974 { 1975 tcp_skb_tsorted_anchor_cleanup(skb); 1976 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue); 1977 } 1978 1979 static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk) 1980 { 1981 list_del(&skb->tcp_tsorted_anchor); 1982 tcp_rtx_queue_unlink(skb, sk); 1983 tcp_wmem_free_skb(sk, skb); 1984 } 1985 1986 static inline void tcp_push_pending_frames(struct sock *sk) 1987 { 1988 if (tcp_send_head(sk)) { 1989 struct tcp_sock *tp = tcp_sk(sk); 1990 1991 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 1992 } 1993 } 1994 1995 /* Start sequence of the skb just after the highest skb with SACKed 1996 * bit, valid only if sacked_out > 0 or when the caller has ensured 1997 * validity by itself. 1998 */ 1999 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 2000 { 2001 if (!tp->sacked_out) 2002 return tp->snd_una; 2003 2004 if (tp->highest_sack == NULL) 2005 return tp->snd_nxt; 2006 2007 return TCP_SKB_CB(tp->highest_sack)->seq; 2008 } 2009 2010 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 2011 { 2012 tcp_sk(sk)->highest_sack = skb_rb_next(skb); 2013 } 2014 2015 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 2016 { 2017 return tcp_sk(sk)->highest_sack; 2018 } 2019 2020 static inline void tcp_highest_sack_reset(struct sock *sk) 2021 { 2022 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk); 2023 } 2024 2025 /* Called when old skb is about to be deleted and replaced by new skb */ 2026 static inline void tcp_highest_sack_replace(struct sock *sk, 2027 struct sk_buff *old, 2028 struct sk_buff *new) 2029 { 2030 if (old == tcp_highest_sack(sk)) 2031 tcp_sk(sk)->highest_sack = new; 2032 } 2033 2034 /* This helper checks if socket has IP_TRANSPARENT set */ 2035 static inline bool inet_sk_transparent(const struct sock *sk) 2036 { 2037 switch (sk->sk_state) { 2038 case TCP_TIME_WAIT: 2039 return inet_twsk(sk)->tw_transparent; 2040 case TCP_NEW_SYN_RECV: 2041 return inet_rsk(inet_reqsk(sk))->no_srccheck; 2042 } 2043 return inet_test_bit(TRANSPARENT, sk); 2044 } 2045 2046 /* Determines whether this is a thin stream (which may suffer from 2047 * increased latency). Used to trigger latency-reducing mechanisms. 2048 */ 2049 static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 2050 { 2051 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); 2052 } 2053 2054 /* /proc */ 2055 enum tcp_seq_states { 2056 TCP_SEQ_STATE_LISTENING, 2057 TCP_SEQ_STATE_ESTABLISHED, 2058 }; 2059 2060 void *tcp_seq_start(struct seq_file *seq, loff_t *pos); 2061 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 2062 void tcp_seq_stop(struct seq_file *seq, void *v); 2063 2064 struct tcp_seq_afinfo { 2065 sa_family_t family; 2066 }; 2067 2068 struct tcp_iter_state { 2069 struct seq_net_private p; 2070 enum tcp_seq_states state; 2071 struct sock *syn_wait_sk; 2072 int bucket, offset, sbucket, num; 2073 loff_t last_pos; 2074 }; 2075 2076 extern struct request_sock_ops tcp_request_sock_ops; 2077 extern struct request_sock_ops tcp6_request_sock_ops; 2078 2079 void tcp_v4_destroy_sock(struct sock *sk); 2080 2081 struct sk_buff *tcp_gso_segment(struct sk_buff *skb, 2082 netdev_features_t features); 2083 struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb); 2084 INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff)); 2085 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)); 2086 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff)); 2087 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)); 2088 void tcp_gro_complete(struct sk_buff *skb); 2089 2090 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 2091 2092 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) 2093 { 2094 struct net *net = sock_net((struct sock *)tp); 2095 u32 val; 2096 2097 val = READ_ONCE(tp->notsent_lowat); 2098 2099 return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); 2100 } 2101 2102 bool tcp_stream_memory_free(const struct sock *sk, int wake); 2103 2104 #ifdef CONFIG_PROC_FS 2105 int tcp4_proc_init(void); 2106 void tcp4_proc_exit(void); 2107 #endif 2108 2109 int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); 2110 int tcp_conn_request(struct request_sock_ops *rsk_ops, 2111 const struct tcp_request_sock_ops *af_ops, 2112 struct sock *sk, struct sk_buff *skb); 2113 2114 /* TCP af-specific functions */ 2115 struct tcp_sock_af_ops { 2116 #ifdef CONFIG_TCP_MD5SIG 2117 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk, 2118 const struct sock *addr_sk); 2119 int (*calc_md5_hash)(char *location, 2120 const struct tcp_md5sig_key *md5, 2121 const struct sock *sk, 2122 const struct sk_buff *skb); 2123 int (*md5_parse)(struct sock *sk, 2124 int optname, 2125 sockptr_t optval, 2126 int optlen); 2127 #endif 2128 }; 2129 2130 struct tcp_request_sock_ops { 2131 u16 mss_clamp; 2132 #ifdef CONFIG_TCP_MD5SIG 2133 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk, 2134 const struct sock *addr_sk); 2135 int (*calc_md5_hash) (char *location, 2136 const struct tcp_md5sig_key *md5, 2137 const struct sock *sk, 2138 const struct sk_buff *skb); 2139 #endif 2140 #ifdef CONFIG_SYN_COOKIES 2141 __u32 (*cookie_init_seq)(const struct sk_buff *skb, 2142 __u16 *mss); 2143 #endif 2144 struct dst_entry *(*route_req)(const struct sock *sk, 2145 struct sk_buff *skb, 2146 struct flowi *fl, 2147 struct request_sock *req); 2148 u32 (*init_seq)(const struct sk_buff *skb); 2149 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb); 2150 int (*send_synack)(const struct sock *sk, struct dst_entry *dst, 2151 struct flowi *fl, struct request_sock *req, 2152 struct tcp_fastopen_cookie *foc, 2153 enum tcp_synack_type synack_type, 2154 struct sk_buff *syn_skb); 2155 }; 2156 2157 extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops; 2158 #if IS_ENABLED(CONFIG_IPV6) 2159 extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops; 2160 #endif 2161 2162 #ifdef CONFIG_SYN_COOKIES 2163 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2164 const struct sock *sk, struct sk_buff *skb, 2165 __u16 *mss) 2166 { 2167 tcp_synq_overflow(sk); 2168 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 2169 return ops->cookie_init_seq(skb, mss); 2170 } 2171 #else 2172 static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, 2173 const struct sock *sk, struct sk_buff *skb, 2174 __u16 *mss) 2175 { 2176 return 0; 2177 } 2178 #endif 2179 2180 int tcpv4_offload_init(void); 2181 2182 void tcp_v4_init(void); 2183 void tcp_init(void); 2184 2185 /* tcp_recovery.c */ 2186 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb); 2187 void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced); 2188 extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, 2189 u32 reo_wnd); 2190 extern bool tcp_rack_mark_lost(struct sock *sk); 2191 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq, 2192 u64 xmit_time); 2193 extern void tcp_rack_reo_timeout(struct sock *sk); 2194 extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs); 2195 2196 /* tcp_plb.c */ 2197 2198 /* 2199 * Scaling factor for fractions in PLB. For example, tcp_plb_update_state 2200 * expects cong_ratio which represents fraction of traffic that experienced 2201 * congestion over a single RTT. In order to avoid floating point operations, 2202 * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in. 2203 */ 2204 #define TCP_PLB_SCALE 8 2205 2206 /* State for PLB (Protective Load Balancing) for a single TCP connection. */ 2207 struct tcp_plb_state { 2208 u8 consec_cong_rounds:5, /* consecutive congested rounds */ 2209 unused:3; 2210 u32 pause_until; /* jiffies32 when PLB can resume rerouting */ 2211 }; 2212 2213 static inline void tcp_plb_init(const struct sock *sk, 2214 struct tcp_plb_state *plb) 2215 { 2216 plb->consec_cong_rounds = 0; 2217 plb->pause_until = 0; 2218 } 2219 void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb, 2220 const int cong_ratio); 2221 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb); 2222 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb); 2223 2224 /* At how many usecs into the future should the RTO fire? */ 2225 static inline s64 tcp_rto_delta_us(const struct sock *sk) 2226 { 2227 const struct sk_buff *skb = tcp_rtx_queue_head(sk); 2228 u32 rto = inet_csk(sk)->icsk_rto; 2229 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto); 2230 2231 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp; 2232 } 2233 2234 /* 2235 * Save and compile IPv4 options, return a pointer to it 2236 */ 2237 static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net, 2238 struct sk_buff *skb) 2239 { 2240 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt; 2241 struct ip_options_rcu *dopt = NULL; 2242 2243 if (opt->optlen) { 2244 int opt_size = sizeof(*dopt) + opt->optlen; 2245 2246 dopt = kmalloc(opt_size, GFP_ATOMIC); 2247 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) { 2248 kfree(dopt); 2249 dopt = NULL; 2250 } 2251 } 2252 return dopt; 2253 } 2254 2255 /* locally generated TCP pure ACKs have skb->truesize == 2 2256 * (check tcp_send_ack() in net/ipv4/tcp_output.c ) 2257 * This is much faster than dissecting the packet to find out. 2258 * (Think of GRE encapsulations, IPv4, IPv6, ...) 2259 */ 2260 static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb) 2261 { 2262 return skb->truesize == 2; 2263 } 2264 2265 static inline void skb_set_tcp_pure_ack(struct sk_buff *skb) 2266 { 2267 skb->truesize = 2; 2268 } 2269 2270 static inline int tcp_inq(struct sock *sk) 2271 { 2272 struct tcp_sock *tp = tcp_sk(sk); 2273 int answ; 2274 2275 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 2276 answ = 0; 2277 } else if (sock_flag(sk, SOCK_URGINLINE) || 2278 !tp->urg_data || 2279 before(tp->urg_seq, tp->copied_seq) || 2280 !before(tp->urg_seq, tp->rcv_nxt)) { 2281 2282 answ = tp->rcv_nxt - tp->copied_seq; 2283 2284 /* Subtract 1, if FIN was received */ 2285 if (answ && sock_flag(sk, SOCK_DONE)) 2286 answ--; 2287 } else { 2288 answ = tp->urg_seq - tp->copied_seq; 2289 } 2290 2291 return answ; 2292 } 2293 2294 int tcp_peek_len(struct socket *sock); 2295 2296 static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) 2297 { 2298 u16 segs_in; 2299 2300 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs); 2301 2302 /* We update these fields while other threads might 2303 * read them from tcp_get_info() 2304 */ 2305 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in); 2306 if (skb->len > tcp_hdrlen(skb)) 2307 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in); 2308 } 2309 2310 /* 2311 * TCP listen path runs lockless. 2312 * We forced "struct sock" to be const qualified to make sure 2313 * we don't modify one of its field by mistake. 2314 * Here, we increment sk_drops which is an atomic_t, so we can safely 2315 * make sock writable again. 2316 */ 2317 static inline void tcp_listendrop(const struct sock *sk) 2318 { 2319 atomic_inc(&((struct sock *)sk)->sk_drops); 2320 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 2321 } 2322 2323 enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); 2324 2325 /* 2326 * Interface for adding Upper Level Protocols over TCP 2327 */ 2328 2329 #define TCP_ULP_NAME_MAX 16 2330 #define TCP_ULP_MAX 128 2331 #define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) 2332 2333 struct tcp_ulp_ops { 2334 struct list_head list; 2335 2336 /* initialize ulp */ 2337 int (*init)(struct sock *sk); 2338 /* update ulp */ 2339 void (*update)(struct sock *sk, struct proto *p, 2340 void (*write_space)(struct sock *sk)); 2341 /* cleanup ulp */ 2342 void (*release)(struct sock *sk); 2343 /* diagnostic */ 2344 int (*get_info)(const struct sock *sk, struct sk_buff *skb); 2345 size_t (*get_info_size)(const struct sock *sk); 2346 /* clone ulp */ 2347 void (*clone)(const struct request_sock *req, struct sock *newsk, 2348 const gfp_t priority); 2349 2350 char name[TCP_ULP_NAME_MAX]; 2351 struct module *owner; 2352 }; 2353 int tcp_register_ulp(struct tcp_ulp_ops *type); 2354 void tcp_unregister_ulp(struct tcp_ulp_ops *type); 2355 int tcp_set_ulp(struct sock *sk, const char *name); 2356 void tcp_get_available_ulp(char *buf, size_t len); 2357 void tcp_cleanup_ulp(struct sock *sk); 2358 void tcp_update_ulp(struct sock *sk, struct proto *p, 2359 void (*write_space)(struct sock *sk)); 2360 2361 #define MODULE_ALIAS_TCP_ULP(name) \ 2362 __MODULE_INFO(alias, alias_userspace, name); \ 2363 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name) 2364 2365 #ifdef CONFIG_NET_SOCK_MSG 2366 struct sk_msg; 2367 struct sk_psock; 2368 2369 #ifdef CONFIG_BPF_SYSCALL 2370 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 2371 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); 2372 #endif /* CONFIG_BPF_SYSCALL */ 2373 2374 #ifdef CONFIG_INET 2375 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); 2376 #else 2377 static inline void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) 2378 { 2379 } 2380 #endif 2381 2382 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 2383 struct sk_msg *msg, u32 bytes, int flags); 2384 #endif /* CONFIG_NET_SOCK_MSG */ 2385 2386 #if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG) 2387 static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 2388 { 2389 } 2390 #endif 2391 2392 #ifdef CONFIG_CGROUP_BPF 2393 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2394 struct sk_buff *skb, 2395 unsigned int end_offset) 2396 { 2397 skops->skb = skb; 2398 skops->skb_data_end = skb->data + end_offset; 2399 } 2400 #else 2401 static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops, 2402 struct sk_buff *skb, 2403 unsigned int end_offset) 2404 { 2405 } 2406 #endif 2407 2408 /* Call BPF_SOCK_OPS program that returns an int. If the return value 2409 * is < 0, then the BPF op failed (for example if the loaded BPF 2410 * program does not support the chosen operation or there is no BPF 2411 * program loaded). 2412 */ 2413 #ifdef CONFIG_BPF 2414 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2415 { 2416 struct bpf_sock_ops_kern sock_ops; 2417 int ret; 2418 2419 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); 2420 if (sk_fullsock(sk)) { 2421 sock_ops.is_fullsock = 1; 2422 sock_owned_by_me(sk); 2423 } 2424 2425 sock_ops.sk = sk; 2426 sock_ops.op = op; 2427 if (nargs > 0) 2428 memcpy(sock_ops.args, args, nargs * sizeof(*args)); 2429 2430 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); 2431 if (ret == 0) 2432 ret = sock_ops.reply; 2433 else 2434 ret = -1; 2435 return ret; 2436 } 2437 2438 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2439 { 2440 u32 args[2] = {arg1, arg2}; 2441 2442 return tcp_call_bpf(sk, op, 2, args); 2443 } 2444 2445 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2446 u32 arg3) 2447 { 2448 u32 args[3] = {arg1, arg2, arg3}; 2449 2450 return tcp_call_bpf(sk, op, 3, args); 2451 } 2452 2453 #else 2454 static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) 2455 { 2456 return -EPERM; 2457 } 2458 2459 static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2) 2460 { 2461 return -EPERM; 2462 } 2463 2464 static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, 2465 u32 arg3) 2466 { 2467 return -EPERM; 2468 } 2469 2470 #endif 2471 2472 static inline u32 tcp_timeout_init(struct sock *sk) 2473 { 2474 int timeout; 2475 2476 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL); 2477 2478 if (timeout <= 0) 2479 timeout = TCP_TIMEOUT_INIT; 2480 return min_t(int, timeout, TCP_RTO_MAX); 2481 } 2482 2483 static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 2484 { 2485 int rwnd; 2486 2487 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL); 2488 2489 if (rwnd < 0) 2490 rwnd = 0; 2491 return rwnd; 2492 } 2493 2494 static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) 2495 { 2496 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1); 2497 } 2498 2499 static inline void tcp_bpf_rtt(struct sock *sk) 2500 { 2501 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG)) 2502 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL); 2503 } 2504 2505 #if IS_ENABLED(CONFIG_SMC) 2506 extern struct static_key_false tcp_have_smc; 2507 #endif 2508 2509 #if IS_ENABLED(CONFIG_TLS_DEVICE) 2510 void clean_acked_data_enable(struct inet_connection_sock *icsk, 2511 void (*cad)(struct sock *sk, u32 ack_seq)); 2512 void clean_acked_data_disable(struct inet_connection_sock *icsk); 2513 void clean_acked_data_flush(void); 2514 #endif 2515 2516 DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled); 2517 static inline void tcp_add_tx_delay(struct sk_buff *skb, 2518 const struct tcp_sock *tp) 2519 { 2520 if (static_branch_unlikely(&tcp_tx_delay_enabled)) 2521 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC; 2522 } 2523 2524 /* Compute Earliest Departure Time for some control packets 2525 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets. 2526 */ 2527 static inline u64 tcp_transmit_time(const struct sock *sk) 2528 { 2529 if (static_branch_unlikely(&tcp_tx_delay_enabled)) { 2530 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ? 2531 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay; 2532 2533 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC; 2534 } 2535 return 0; 2536 } 2537 2538 #endif /* _TCP_H */ 2539