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 protocol.
8 *
9 * Version: @(#)tcp.h 1.0.2 04/28/93
10 *
11 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 */
13 #ifndef _LINUX_TCP_H
14 #define _LINUX_TCP_H
15
16
17 #include <linux/skbuff.h>
18 #include <linux/win_minmax.h>
19 #include <linux/android_kabi.h>
20 #include <net/sock.h>
21 #include <net/inet_connection_sock.h>
22 #include <net/inet_timewait_sock.h>
23 #include <uapi/linux/tcp.h>
24
tcp_hdr(const struct sk_buff * skb)25 static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
26 {
27 return (struct tcphdr *)skb_transport_header(skb);
28 }
29
__tcp_hdrlen(const struct tcphdr * th)30 static inline unsigned int __tcp_hdrlen(const struct tcphdr *th)
31 {
32 return th->doff * 4;
33 }
34
tcp_hdrlen(const struct sk_buff * skb)35 static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
36 {
37 return __tcp_hdrlen(tcp_hdr(skb));
38 }
39
inner_tcp_hdr(const struct sk_buff * skb)40 static inline struct tcphdr *inner_tcp_hdr(const struct sk_buff *skb)
41 {
42 return (struct tcphdr *)skb_inner_transport_header(skb);
43 }
44
inner_tcp_hdrlen(const struct sk_buff * skb)45 static inline unsigned int inner_tcp_hdrlen(const struct sk_buff *skb)
46 {
47 return inner_tcp_hdr(skb)->doff * 4;
48 }
49
50 /**
51 * skb_tcp_all_headers - Returns size of all headers for a TCP packet
52 * @skb: buffer
53 *
54 * Used in TX path, for a packet known to be a TCP one.
55 *
56 * if (skb_is_gso(skb)) {
57 * int hlen = skb_tcp_all_headers(skb);
58 * ...
59 */
skb_tcp_all_headers(const struct sk_buff * skb)60 static inline int skb_tcp_all_headers(const struct sk_buff *skb)
61 {
62 return skb_transport_offset(skb) + tcp_hdrlen(skb);
63 }
64
65 /**
66 * skb_inner_tcp_all_headers - Returns size of all headers for an encap TCP packet
67 * @skb: buffer
68 *
69 * Used in TX path, for a packet known to be a TCP one.
70 *
71 * if (skb_is_gso(skb) && skb->encapsulation) {
72 * int hlen = skb_inner_tcp_all_headers(skb);
73 * ...
74 */
skb_inner_tcp_all_headers(const struct sk_buff * skb)75 static inline int skb_inner_tcp_all_headers(const struct sk_buff *skb)
76 {
77 return skb_inner_transport_offset(skb) + inner_tcp_hdrlen(skb);
78 }
79
tcp_optlen(const struct sk_buff * skb)80 static inline unsigned int tcp_optlen(const struct sk_buff *skb)
81 {
82 return (tcp_hdr(skb)->doff - 5) * 4;
83 }
84
85 /* TCP Fast Open */
86 #define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */
87 #define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */
88 #define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */
89
90 /* TCP Fast Open Cookie as stored in memory */
91 struct tcp_fastopen_cookie {
92 __le64 val[DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))];
93 s8 len;
94 bool exp; /* In RFC6994 experimental option format */
95 };
96
97 /* This defines a selective acknowledgement block. */
98 struct tcp_sack_block_wire {
99 __be32 start_seq;
100 __be32 end_seq;
101 };
102
103 struct tcp_sack_block {
104 u32 start_seq;
105 u32 end_seq;
106 };
107
108 /*These are used to set the sack_ok field in struct tcp_options_received */
109 #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */
110 #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/
111
112 struct tcp_options_received {
113 /* PAWS/RTTM data */
114 int ts_recent_stamp;/* Time we stored ts_recent (for aging) */
115 u32 ts_recent; /* Time stamp to echo next */
116 u32 rcv_tsval; /* Time stamp value */
117 u32 rcv_tsecr; /* Time stamp echo reply */
118 u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
119 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
120 dsack : 1, /* D-SACK is scheduled */
121 wscale_ok : 1, /* Wscale seen on SYN packet */
122 sack_ok : 3, /* SACK seen on SYN packet */
123 smc_ok : 1, /* SMC seen on SYN packet */
124 snd_wscale : 4, /* Window scaling received from sender */
125 rcv_wscale : 4; /* Window scaling to send to receiver */
126 u8 saw_unknown:1, /* Received unknown option */
127 unused:7;
128 u8 num_sacks; /* Number of SACK blocks */
129 u16 user_mss; /* mss requested by user in ioctl */
130 u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
131 };
132
tcp_clear_options(struct tcp_options_received * rx_opt)133 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
134 {
135 rx_opt->tstamp_ok = rx_opt->sack_ok = 0;
136 rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
137 #if IS_ENABLED(CONFIG_SMC)
138 rx_opt->smc_ok = 0;
139 #endif
140 }
141
142 /* This is the max number of SACKS that we'll generate and process. It's safe
143 * to increase this, although since:
144 * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
145 * only four options will fit in a standard TCP header */
146 #define TCP_NUM_SACKS 4
147
148 struct tcp_request_sock_ops;
149
150 struct tcp_request_sock {
151 struct inet_request_sock req;
152 const struct tcp_request_sock_ops *af_specific;
153 u64 snt_synack; /* first SYNACK sent time */
154 bool tfo_listener;
155 bool is_mptcp;
156 #if IS_ENABLED(CONFIG_MPTCP)
157 bool drop_req;
158 #endif
159 u32 txhash;
160 u32 rcv_isn;
161 u32 snt_isn;
162 u32 ts_off;
163 u32 last_oow_ack_time; /* last SYNACK */
164 u32 rcv_nxt; /* the ack # by SYNACK. For
165 * FastOpen it's the seq#
166 * after data-in-SYN.
167 */
168 u8 syn_tos;
169 };
170
tcp_rsk(const struct request_sock * req)171 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
172 {
173 return (struct tcp_request_sock *)req;
174 }
175
176 #define TCP_RMEM_TO_WIN_SCALE 8
177
178 struct tcp_sock {
179 /* inet_connection_sock has to be the first member of tcp_sock */
180 struct inet_connection_sock inet_conn;
181 u16 tcp_header_len; /* Bytes of tcp header to send */
182 u16 gso_segs; /* Max number of segs per GSO packet */
183
184 /*
185 * Header prediction flags
186 * 0x5?10 << 16 + snd_wnd in net byte order
187 */
188 __be32 pred_flags;
189
190 /*
191 * RFC793 variables by their proper names. This means you can
192 * read the code and the spec side by side (and laugh ...)
193 * See RFC793 and RFC1122. The RFC writes these in capitals.
194 */
195 u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
196 * sum(delta(rcv_nxt)), or how many bytes
197 * were acked.
198 */
199 u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
200 * total number of segments in.
201 */
202 u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
203 * total number of data segments in.
204 */
205 u32 rcv_nxt; /* What we want to receive next */
206 u32 copied_seq; /* Head of yet unread data */
207 u32 rcv_wup; /* rcv_nxt on last window update sent */
208 u32 snd_nxt; /* Next sequence we send */
209 u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
210 * The total number of segments sent.
211 */
212 u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
213 * total number of data segments sent.
214 */
215 u64 bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut
216 * total number of data bytes sent.
217 */
218 u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
219 * sum(delta(snd_una)), or how many bytes
220 * were acked.
221 */
222 u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
223 * total number of DSACK blocks received
224 */
225 u32 snd_una; /* First byte we want an ack for */
226 u32 snd_sml; /* Last byte of the most recently transmitted small packet */
227 u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
228 u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
229 u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */
230 u32 compressed_ack_rcv_nxt;
231
232 u32 tsoffset; /* timestamp offset */
233
234 struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
235 struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */
236
237 u32 snd_wl1; /* Sequence for window update */
238 u32 snd_wnd; /* The window we expect to receive */
239 u32 max_window; /* Maximal window ever seen from peer */
240 u32 mss_cache; /* Cached effective mss, not including SACKS */
241
242 u32 window_clamp; /* Maximal window to advertise */
243 u32 rcv_ssthresh; /* Current window clamp */
244 u8 scaling_ratio; /* see tcp_win_from_space() */
245 /* Information of the most recently (s)acked skb */
246 struct tcp_rack {
247 u64 mstamp; /* (Re)sent time of the skb */
248 u32 rtt_us; /* Associated RTT */
249 u32 end_seq; /* Ending TCP sequence of the skb */
250 u32 last_delivered; /* tp->delivered at last reo_wnd adj */
251 u8 reo_wnd_steps; /* Allowed reordering window */
252 #define TCP_RACK_RECOVERY_THRESH 16
253 u8 reo_wnd_persist:5, /* No. of recovery since last adj */
254 dsack_seen:1, /* Whether DSACK seen after last adj */
255 advanced:1; /* mstamp advanced since last lost marking */
256 } rack;
257 u16 advmss; /* Advertised MSS */
258 u8 compressed_ack;
259 u8 dup_ack_counter:2,
260 tlp_retrans:1, /* TLP is a retransmission */
261 unused:5;
262 u32 chrono_start; /* Start time in jiffies of a TCP chrono */
263 u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */
264 u8 chrono_type:2, /* current chronograph type */
265 rate_app_limited:1, /* rate_{delivered,interval_us} limited? */
266 fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */
267 fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */
268 is_sack_reneg:1, /* in recovery from loss with SACK reneg? */
269 fastopen_client_fail:2; /* reason why fastopen failed */
270 u8 nonagle : 4,/* Disable Nagle algorithm? */
271 thin_lto : 1,/* Use linear timeouts for thin streams */
272 recvmsg_inq : 1,/* Indicate # of bytes in queue upon recvmsg */
273 repair : 1,
274 frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */
275 u8 repair_queue;
276 u8 save_syn:2, /* Save headers of SYN packet */
277 syn_data:1, /* SYN includes data */
278 syn_fastopen:1, /* SYN includes Fast Open option */
279 syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
280 syn_fastopen_ch:1, /* Active TFO re-enabling probe */
281 syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
282 is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */
283 u32 tlp_high_seq; /* snd_nxt at the time of TLP */
284
285 u32 tcp_tx_delay; /* delay (in usec) added to TX packets */
286 u64 tcp_wstamp_ns; /* departure time for next sent data packet */
287 u64 tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */
288
289 /* RTT measurement */
290 u64 tcp_mstamp; /* most recent packet received/sent */
291 u32 srtt_us; /* smoothed round trip time << 3 in usecs */
292 u32 mdev_us; /* medium deviation */
293 u32 mdev_max_us; /* maximal mdev for the last rtt period */
294 u32 rttvar_us; /* smoothed mdev_max */
295 u32 rtt_seq; /* sequence number to update rttvar */
296 struct minmax rtt_min;
297
298 u32 packets_out; /* Packets which are "in flight" */
299 u32 retrans_out; /* Retransmitted packets out */
300 u32 max_packets_out; /* max packets_out in last window */
301 u32 cwnd_usage_seq; /* right edge of cwnd usage tracking flight */
302
303 u16 urg_data; /* Saved octet of OOB data and control flags */
304 u8 ecn_flags; /* ECN status bits. */
305 u8 keepalive_probes; /* num of allowed keep alive probes */
306 u32 reordering; /* Packet reordering metric. */
307 u32 reord_seen; /* number of data packet reordering events */
308 u32 snd_up; /* Urgent pointer */
309
310 /*
311 * Options received (usually on last packet, some only on SYN packets).
312 */
313 struct tcp_options_received rx_opt;
314
315 /*
316 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
317 */
318 u32 snd_ssthresh; /* Slow start size threshold */
319 u32 snd_cwnd; /* Sending congestion window */
320 u32 snd_cwnd_cnt; /* Linear increase counter */
321 u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
322 u32 snd_cwnd_used;
323 u32 snd_cwnd_stamp;
324 u32 prior_cwnd; /* cwnd right before starting loss recovery */
325 u32 prr_delivered; /* Number of newly delivered packets to
326 * receiver in Recovery. */
327 u32 prr_out; /* Total number of pkts sent during Recovery. */
328 u32 delivered; /* Total data packets delivered incl. rexmits */
329 u32 delivered_ce; /* Like the above but only ECE marked packets */
330 u32 lost; /* Total data packets lost incl. rexmits */
331 u32 app_limited; /* limited until "delivered" reaches this val */
332 u64 first_tx_mstamp; /* start of window send phase */
333 u64 delivered_mstamp; /* time we reached "delivered" */
334 u32 rate_delivered; /* saved rate sample: packets delivered */
335 u32 rate_interval_us; /* saved rate sample: time elapsed */
336
337 u32 rcv_wnd; /* Current receiver window */
338 u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
339 u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */
340 u32 pushed_seq; /* Last pushed seq, required to talk to windows */
341 u32 lost_out; /* Lost packets */
342 u32 sacked_out; /* SACK'd packets */
343
344 struct hrtimer pacing_timer;
345 struct hrtimer compressed_ack_timer;
346
347 /* from STCP, retrans queue hinting */
348 struct sk_buff* lost_skb_hint;
349 struct sk_buff *retransmit_skb_hint;
350
351 /* OOO segments go in this rbtree. Socket lock must be held. */
352 struct rb_root out_of_order_queue;
353 struct sk_buff *ooo_last_skb; /* cache rb_last(out_of_order_queue) */
354
355 /* SACKs data, these 2 need to be together (see tcp_options_write) */
356 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
357 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
358
359 struct tcp_sack_block recv_sack_cache[4];
360
361 struct sk_buff *highest_sack; /* skb just after the highest
362 * skb with SACKed bit set
363 * (validity guaranteed only if
364 * sacked_out > 0)
365 */
366
367 int lost_cnt_hint;
368
369 u32 prior_ssthresh; /* ssthresh saved at recovery start */
370 u32 high_seq; /* snd_nxt at onset of congestion */
371
372 u32 retrans_stamp; /* Timestamp of the last retransmit,
373 * also used in SYN-SENT to remember stamp of
374 * the first SYN. */
375 u32 undo_marker; /* snd_una upon a new recovery episode. */
376 int undo_retrans; /* number of undoable retransmissions. */
377 u64 bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans
378 * Total data bytes retransmitted
379 */
380 u32 total_retrans; /* Total retransmits for entire connection */
381
382 u32 urg_seq; /* Seq of received urgent pointer */
383 unsigned int keepalive_time; /* time before keep alive takes place */
384 unsigned int keepalive_intvl; /* time interval between keep alive probes */
385
386 int linger2;
387
388
389 /* Sock_ops bpf program related variables */
390 #ifdef CONFIG_BPF
391 u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs
392 * values defined in uapi/linux/tcp.h
393 */
394 u8 bpf_chg_cc_inprogress:1; /* In the middle of
395 * bpf_setsockopt(TCP_CONGESTION),
396 * it is to avoid the bpf_tcp_cc->init()
397 * to recur itself by calling
398 * bpf_setsockopt(TCP_CONGESTION, "itself").
399 */
400 #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG)
401 #else
402 #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0
403 #endif
404
405 u16 timeout_rehash; /* Timeout-triggered rehash attempts */
406
407 u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */
408
409 /* Receiver side RTT estimation */
410 u32 rcv_rtt_last_tsecr;
411 struct {
412 u32 rtt_us;
413 u32 seq;
414 u64 time;
415 } rcv_rtt_est;
416
417 /* Receiver queue space */
418 struct {
419 u32 space;
420 u32 seq;
421 u64 time;
422 } rcvq_space;
423
424 /* TCP-specific MTU probe information. */
425 struct {
426 u32 probe_seq_start;
427 u32 probe_seq_end;
428 } mtu_probe;
429 u32 plb_rehash; /* PLB-triggered rehash attempts */
430 u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
431 * while socket was owned by user.
432 */
433 #if IS_ENABLED(CONFIG_MPTCP)
434 bool is_mptcp;
435 #endif
436 #if IS_ENABLED(CONFIG_SMC)
437 bool (*smc_hs_congested)(const struct sock *sk);
438 bool syn_smc; /* SYN includes SMC */
439 #endif
440
441 #ifdef CONFIG_TCP_MD5SIG
442 /* TCP AF-Specific parts; only used by MD5 Signature support so far */
443 const struct tcp_sock_af_ops *af_specific;
444
445 /* TCP MD5 Signature Option information */
446 struct tcp_md5sig_info __rcu *md5sig_info;
447 #endif
448
449 /* TCP fastopen related information */
450 struct tcp_fastopen_request *fastopen_req;
451 /* fastopen_rsk points to request_sock that resulted in this big
452 * socket. Used to retransmit SYNACKs etc.
453 */
454 struct request_sock __rcu *fastopen_rsk;
455 struct saved_syn *saved_syn;
456
457 ANDROID_OEM_DATA(1);
458 ANDROID_KABI_RESERVE(1);
459 };
460
461 enum tsq_enum {
462 TSQ_THROTTLED,
463 TSQ_QUEUED,
464 TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */
465 TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */
466 TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */
467 TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call
468 * tcp_v{4|6}_mtu_reduced()
469 */
470 };
471
472 enum tsq_flags {
473 TSQF_THROTTLED = (1UL << TSQ_THROTTLED),
474 TSQF_QUEUED = (1UL << TSQ_QUEUED),
475 TCPF_TSQ_DEFERRED = (1UL << TCP_TSQ_DEFERRED),
476 TCPF_WRITE_TIMER_DEFERRED = (1UL << TCP_WRITE_TIMER_DEFERRED),
477 TCPF_DELACK_TIMER_DEFERRED = (1UL << TCP_DELACK_TIMER_DEFERRED),
478 TCPF_MTU_REDUCED_DEFERRED = (1UL << TCP_MTU_REDUCED_DEFERRED),
479 };
480
481 #define tcp_sk(ptr) container_of_const(ptr, struct tcp_sock, inet_conn.icsk_inet.sk)
482
483 /* Variant of tcp_sk() upgrading a const sock to a read/write tcp socket.
484 * Used in context of (lockless) tcp listeners.
485 */
486 #define tcp_sk_rw(ptr) container_of(ptr, struct tcp_sock, inet_conn.icsk_inet.sk)
487
488 struct tcp_timewait_sock {
489 struct inet_timewait_sock tw_sk;
490 #define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt
491 #define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt
492 u32 tw_rcv_wnd;
493 u32 tw_ts_offset;
494 u32 tw_ts_recent;
495
496 /* The time we sent the last out-of-window ACK: */
497 u32 tw_last_oow_ack_time;
498
499 int tw_ts_recent_stamp;
500 u32 tw_tx_delay;
501 #ifdef CONFIG_TCP_MD5SIG
502 struct tcp_md5sig_key *tw_md5_key;
503 #endif
504 };
505
tcp_twsk(const struct sock * sk)506 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
507 {
508 return (struct tcp_timewait_sock *)sk;
509 }
510
tcp_passive_fastopen(const struct sock * sk)511 static inline bool tcp_passive_fastopen(const struct sock *sk)
512 {
513 return sk->sk_state == TCP_SYN_RECV &&
514 rcu_access_pointer(tcp_sk(sk)->fastopen_rsk) != NULL;
515 }
516
fastopen_queue_tune(struct sock * sk,int backlog)517 static inline void fastopen_queue_tune(struct sock *sk, int backlog)
518 {
519 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
520 int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn);
521
522 WRITE_ONCE(queue->fastopenq.max_qlen, min_t(unsigned int, backlog, somaxconn));
523 }
524
tcp_move_syn(struct tcp_sock * tp,struct request_sock * req)525 static inline void tcp_move_syn(struct tcp_sock *tp,
526 struct request_sock *req)
527 {
528 tp->saved_syn = req->saved_syn;
529 req->saved_syn = NULL;
530 }
531
tcp_saved_syn_free(struct tcp_sock * tp)532 static inline void tcp_saved_syn_free(struct tcp_sock *tp)
533 {
534 kfree(tp->saved_syn);
535 tp->saved_syn = NULL;
536 }
537
tcp_saved_syn_len(const struct saved_syn * saved_syn)538 static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn)
539 {
540 return saved_syn->mac_hdrlen + saved_syn->network_hdrlen +
541 saved_syn->tcp_hdrlen;
542 }
543
544 struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
545 const struct sk_buff *orig_skb,
546 const struct sk_buff *ack_skb);
547
tcp_mss_clamp(const struct tcp_sock * tp,u16 mss)548 static inline u16 tcp_mss_clamp(const struct tcp_sock *tp, u16 mss)
549 {
550 /* We use READ_ONCE() here because socket might not be locked.
551 * This happens for listeners.
552 */
553 u16 user_mss = READ_ONCE(tp->rx_opt.user_mss);
554
555 return (user_mss && user_mss < mss) ? user_mss : mss;
556 }
557
558 int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
559 int shiftlen);
560
561 void __tcp_sock_set_cork(struct sock *sk, bool on);
562 void tcp_sock_set_cork(struct sock *sk, bool on);
563 int tcp_sock_set_keepcnt(struct sock *sk, int val);
564 int tcp_sock_set_keepidle_locked(struct sock *sk, int val);
565 int tcp_sock_set_keepidle(struct sock *sk, int val);
566 int tcp_sock_set_keepintvl(struct sock *sk, int val);
567 void __tcp_sock_set_nodelay(struct sock *sk, bool on);
568 void tcp_sock_set_nodelay(struct sock *sk);
569 void tcp_sock_set_quickack(struct sock *sk, int val);
570 int tcp_sock_set_syncnt(struct sock *sk, int val);
571 int tcp_sock_set_user_timeout(struct sock *sk, int val);
572
573 #endif /* _LINUX_TCP_H */
574