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 <net/sock.h>
20#include <net/inet_connection_sock.h>
21#include <net/inet_timewait_sock.h>
22#include <uapi/linux/tcp.h>
23
24static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
25{
26 return (struct tcphdr *)skb_transport_header(skb);
27}
28
29static inline unsigned int __tcp_hdrlen(const struct tcphdr *th)
30{
31 return th->doff * 4;
32}
33
34static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
35{
36 return __tcp_hdrlen(th: tcp_hdr(skb));
37}
38
39static inline struct tcphdr *inner_tcp_hdr(const struct sk_buff *skb)
40{
41 return (struct tcphdr *)skb_inner_transport_header(skb);
42}
43
44static inline unsigned int inner_tcp_hdrlen(const struct sk_buff *skb)
45{
46 return inner_tcp_hdr(skb)->doff * 4;
47}
48
49/**
50 * skb_tcp_all_headers - Returns size of all headers for a TCP packet
51 * @skb: buffer
52 *
53 * Used in TX path, for a packet known to be a TCP one.
54 *
55 * if (skb_is_gso(skb)) {
56 * int hlen = skb_tcp_all_headers(skb);
57 * ...
58 */
59static inline int skb_tcp_all_headers(const struct sk_buff *skb)
60{
61 return skb_transport_offset(skb) + tcp_hdrlen(skb);
62}
63
64/**
65 * skb_inner_tcp_all_headers - Returns size of all headers for an encap TCP packet
66 * @skb: buffer
67 *
68 * Used in TX path, for a packet known to be a TCP one.
69 *
70 * if (skb_is_gso(skb) && skb->encapsulation) {
71 * int hlen = skb_inner_tcp_all_headers(skb);
72 * ...
73 */
74static inline int skb_inner_tcp_all_headers(const struct sk_buff *skb)
75{
76 return skb_inner_transport_offset(skb) + inner_tcp_hdrlen(skb);
77}
78
79static inline unsigned int tcp_optlen(const struct sk_buff *skb)
80{
81 return (tcp_hdr(skb)->doff - 5) * 4;
82}
83
84/* TCP Fast Open */
85#define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */
86#define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */
87#define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */
88
89/* TCP Fast Open Cookie as stored in memory */
90struct tcp_fastopen_cookie {
91 __le64 val[DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))];
92 s8 len;
93 bool exp; /* In RFC6994 experimental option format */
94};
95
96/* This defines a selective acknowledgement block. */
97struct tcp_sack_block_wire {
98 __be32 start_seq;
99 __be32 end_seq;
100};
101
102struct tcp_sack_block {
103 u32 start_seq;
104 u32 end_seq;
105};
106
107/*These are used to set the sack_ok field in struct tcp_options_received */
108#define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */
109#define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/
110
111struct tcp_options_received {
112/* PAWS/RTTM data */
113 int ts_recent_stamp;/* Time we stored ts_recent (for aging) */
114 u32 ts_recent; /* Time stamp to echo next */
115 u32 rcv_tsval; /* Time stamp value */
116 u32 rcv_tsecr; /* Time stamp echo reply */
117 u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
118 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
119 dsack : 1, /* D-SACK is scheduled */
120 wscale_ok : 1, /* Wscale seen on SYN packet */
121 sack_ok : 3, /* SACK seen on SYN packet */
122 smc_ok : 1, /* SMC seen on SYN packet */
123 snd_wscale : 4, /* Window scaling received from sender */
124 rcv_wscale : 4; /* Window scaling to send to receiver */
125 u8 saw_unknown:1, /* Received unknown option */
126 unused:7;
127 u8 num_sacks; /* Number of SACK blocks */
128 u16 user_mss; /* mss requested by user in ioctl */
129 u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
130};
131
132static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
133{
134 rx_opt->tstamp_ok = rx_opt->sack_ok = 0;
135 rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
136#if IS_ENABLED(CONFIG_SMC)
137 rx_opt->smc_ok = 0;
138#endif
139}
140
141/* This is the max number of SACKS that we'll generate and process. It's safe
142 * to increase this, although since:
143 * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
144 * only four options will fit in a standard TCP header */
145#define TCP_NUM_SACKS 4
146
147struct tcp_request_sock_ops;
148
149struct tcp_request_sock {
150 struct inet_request_sock req;
151 const struct tcp_request_sock_ops *af_specific;
152 u64 snt_synack; /* first SYNACK sent time */
153 bool tfo_listener;
154 bool is_mptcp;
155 bool req_usec_ts;
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 snt_tsval_first;
164 u32 snt_tsval_last;
165 u32 last_oow_ack_time; /* last SYNACK */
166 u32 rcv_nxt; /* the ack # by SYNACK. For
167 * FastOpen it's the seq#
168 * after data-in-SYN.
169 */
170 u8 syn_tos;
171#ifdef CONFIG_TCP_AO
172 u8 ao_keyid;
173 u8 ao_rcv_next;
174 bool used_tcp_ao;
175#endif
176};
177
178static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
179{
180 return (struct tcp_request_sock *)req;
181}
182
183static inline bool tcp_rsk_used_ao(const struct request_sock *req)
184{
185#ifndef CONFIG_TCP_AO
186 return false;
187#else
188 return tcp_rsk(req)->used_tcp_ao;
189#endif
190}
191
192#define TCP_RMEM_TO_WIN_SCALE 8
193
194struct tcp_sock {
195 /* Cacheline organization can be found documented in
196 * Documentation/networking/net_cachelines/tcp_sock.rst.
197 * Please update the document when adding new fields.
198 */
199
200 /* inet_connection_sock has to be the first member of tcp_sock */
201 struct inet_connection_sock inet_conn;
202
203 /* TX read-mostly hotpath cache lines */
204 __cacheline_group_begin(tcp_sock_read_tx);
205 u32 max_window; /* Maximal window ever seen from peer */
206 u32 rcv_ssthresh; /* Current window clamp */
207 u32 reordering; /* Packet reordering metric. */
208 u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */
209 u16 gso_segs; /* Max number of segs per GSO packet */
210 /* from STCP, retrans queue hinting */
211 struct sk_buff *lost_skb_hint;
212 struct sk_buff *retransmit_skb_hint;
213 __cacheline_group_end(tcp_sock_read_tx);
214
215 /* TXRX read-mostly hotpath cache lines */
216 __cacheline_group_begin(tcp_sock_read_txrx);
217 u32 tsoffset; /* timestamp offset */
218 u32 snd_wnd; /* The window we expect to receive */
219 u32 mss_cache; /* Cached effective mss, not including SACKS */
220 u32 snd_cwnd; /* Sending congestion window */
221 u32 prr_out; /* Total number of pkts sent during Recovery. */
222 u32 lost_out; /* Lost packets */
223 u32 sacked_out; /* SACK'd packets */
224 u16 tcp_header_len; /* Bytes of tcp header to send */
225 u8 scaling_ratio; /* see tcp_win_from_space() */
226 u8 chrono_type : 2, /* current chronograph type */
227 repair : 1,
228 tcp_usec_ts : 1, /* TSval values in usec */
229 is_sack_reneg:1, /* in recovery from loss with SACK reneg? */
230 is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */
231 __cacheline_group_end(tcp_sock_read_txrx);
232
233 /* RX read-mostly hotpath cache lines */
234 __cacheline_group_begin(tcp_sock_read_rx);
235 u32 copied_seq; /* Head of yet unread data */
236 u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
237 u32 snd_wl1; /* Sequence for window update */
238 u32 tlp_high_seq; /* snd_nxt at the time of TLP */
239 u32 rttvar_us; /* smoothed mdev_max */
240 u32 retrans_out; /* Retransmitted packets out */
241 u16 advmss; /* Advertised MSS */
242 u16 urg_data; /* Saved octet of OOB data and control flags */
243 u32 lost; /* Total data packets lost incl. rexmits */
244 struct minmax rtt_min;
245 /* OOO segments go in this rbtree. Socket lock must be held. */
246 struct rb_root out_of_order_queue;
247#if defined(CONFIG_TLS_DEVICE)
248 void (*tcp_clean_acked)(struct sock *sk, u32 acked_seq);
249#endif
250 u32 snd_ssthresh; /* Slow start size threshold */
251 u8 recvmsg_inq : 1;/* Indicate # of bytes in queue upon recvmsg */
252 __cacheline_group_end(tcp_sock_read_rx);
253
254 /* TX read-write hotpath cache lines */
255 __cacheline_group_begin(tcp_sock_write_tx) ____cacheline_aligned;
256 u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
257 * The total number of segments sent.
258 */
259 u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
260 * total number of data segments sent.
261 */
262 u64 bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut
263 * total number of data bytes sent.
264 */
265 u32 snd_sml; /* Last byte of the most recently transmitted small packet */
266 u32 chrono_start; /* Start time in jiffies of a TCP chrono */
267 u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */
268 u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
269 u32 pushed_seq; /* Last pushed seq, required to talk to windows */
270 u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
271 u32 mdev_us; /* medium deviation */
272 u32 rtt_seq; /* sequence number to update rttvar */
273 u64 tcp_wstamp_ns; /* departure time for next sent data packet */
274 struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */
275 struct sk_buff *highest_sack; /* skb just after the highest
276 * skb with SACKed bit set
277 * (validity guaranteed only if
278 * sacked_out > 0)
279 */
280 u8 ecn_flags; /* ECN status bits. */
281 __cacheline_group_end(tcp_sock_write_tx);
282
283 /* TXRX read-write hotpath cache lines */
284 __cacheline_group_begin(tcp_sock_write_txrx);
285/*
286 * Header prediction flags
287 * 0x5?10 << 16 + snd_wnd in net byte order
288 */
289 __be32 pred_flags;
290 u64 tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */
291 u64 tcp_mstamp; /* most recent packet received/sent */
292 u32 rcv_nxt; /* What we want to receive next */
293 u32 snd_nxt; /* Next sequence we send */
294 u32 snd_una; /* First byte we want an ack for */
295 u32 window_clamp; /* Maximal window to advertise */
296 u32 srtt_us; /* smoothed round trip time << 3 in usecs */
297 u32 packets_out; /* Packets which are "in flight" */
298 u32 snd_up; /* Urgent pointer */
299 u32 delivered; /* Total data packets delivered incl. rexmits */
300 u32 delivered_ce; /* Like the above but only ECE marked packets */
301 u32 app_limited; /* limited until "delivered" reaches this val */
302 u32 rcv_wnd; /* Current receiver window */
303/*
304 * Options received (usually on last packet, some only on SYN packets).
305 */
306 struct tcp_options_received rx_opt;
307 u8 nonagle : 4,/* Disable Nagle algorithm? */
308 rate_app_limited:1; /* rate_{delivered,interval_us} limited? */
309 __cacheline_group_end(tcp_sock_write_txrx);
310
311 /* RX read-write hotpath cache lines */
312 __cacheline_group_begin(tcp_sock_write_rx) __aligned(8);
313 u64 bytes_received;
314 /* RFC4898 tcpEStatsAppHCThruOctetsReceived
315 * sum(delta(rcv_nxt)), or how many bytes
316 * were acked.
317 */
318 u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
319 * total number of segments in.
320 */
321 u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
322 * total number of data segments in.
323 */
324 u32 rcv_wup; /* rcv_nxt on last window update sent */
325 u32 max_packets_out; /* max packets_out in last window */
326 u32 cwnd_usage_seq; /* right edge of cwnd usage tracking flight */
327 u32 rate_delivered; /* saved rate sample: packets delivered */
328 u32 rate_interval_us; /* saved rate sample: time elapsed */
329 u32 rcv_rtt_last_tsecr;
330 u64 first_tx_mstamp; /* start of window send phase */
331 u64 delivered_mstamp; /* time we reached "delivered" */
332 u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
333 * sum(delta(snd_una)), or how many bytes
334 * were acked.
335 */
336 struct {
337 u32 rtt_us;
338 u32 seq;
339 u64 time;
340 } rcv_rtt_est;
341/* Receiver queue space */
342 struct {
343 int space;
344 u32 seq;
345 u64 time;
346 } rcvq_space;
347 __cacheline_group_end(tcp_sock_write_rx);
348 /* End of Hot Path */
349
350/*
351 * RFC793 variables by their proper names. This means you can
352 * read the code and the spec side by side (and laugh ...)
353 * See RFC793 and RFC1122. The RFC writes these in capitals.
354 */
355 u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
356 * total number of DSACK blocks received
357 */
358 u32 compressed_ack_rcv_nxt;
359 struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
360
361 /* Information of the most recently (s)acked skb */
362 struct tcp_rack {
363 u64 mstamp; /* (Re)sent time of the skb */
364 u32 rtt_us; /* Associated RTT */
365 u32 end_seq; /* Ending TCP sequence of the skb */
366 u32 last_delivered; /* tp->delivered at last reo_wnd adj */
367 u8 reo_wnd_steps; /* Allowed reordering window */
368#define TCP_RACK_RECOVERY_THRESH 16
369 u8 reo_wnd_persist:5, /* No. of recovery since last adj */
370 dsack_seen:1, /* Whether DSACK seen after last adj */
371 advanced:1; /* mstamp advanced since last lost marking */
372 } rack;
373 u8 compressed_ack;
374 u8 dup_ack_counter:2,
375 tlp_retrans:1, /* TLP is a retransmission */
376 unused:5;
377 u8 thin_lto : 1,/* Use linear timeouts for thin streams */
378 fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */
379 fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */
380 fastopen_client_fail:2, /* reason why fastopen failed */
381 frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */
382 u8 repair_queue;
383 u8 save_syn:2, /* Save headers of SYN packet */
384 syn_data:1, /* SYN includes data */
385 syn_fastopen:1, /* SYN includes Fast Open option */
386 syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
387 syn_fastopen_ch:1, /* Active TFO re-enabling probe */
388 syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
389 syn_fastopen_child:1; /* created TFO passive child socket */
390
391 u8 keepalive_probes; /* num of allowed keep alive probes */
392 u32 tcp_tx_delay; /* delay (in usec) added to TX packets */
393
394/* RTT measurement */
395 u32 mdev_max_us; /* maximal mdev for the last rtt period */
396
397 u32 reord_seen; /* number of data packet reordering events */
398
399/*
400 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
401 */
402 u32 snd_cwnd_cnt; /* Linear increase counter */
403 u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
404 u32 snd_cwnd_used;
405 u32 snd_cwnd_stamp;
406 u32 prior_cwnd; /* cwnd right before starting loss recovery */
407 u32 prr_delivered; /* Number of newly delivered packets to
408 * receiver in Recovery. */
409 u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */
410
411 struct hrtimer pacing_timer;
412 struct hrtimer compressed_ack_timer;
413
414 struct sk_buff *ooo_last_skb; /* cache rb_last(out_of_order_queue) */
415
416 /* SACKs data, these 2 need to be together (see tcp_options_write) */
417 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
418 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
419
420 struct tcp_sack_block recv_sack_cache[4];
421
422 int lost_cnt_hint;
423
424 u32 prior_ssthresh; /* ssthresh saved at recovery start */
425 u32 high_seq; /* snd_nxt at onset of congestion */
426
427 u32 retrans_stamp; /* Timestamp of the last retransmit,
428 * also used in SYN-SENT to remember stamp of
429 * the first SYN. */
430 u32 undo_marker; /* snd_una upon a new recovery episode. */
431 int undo_retrans; /* number of undoable retransmissions. */
432 u64 bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans
433 * Total data bytes retransmitted
434 */
435 u32 total_retrans; /* Total retransmits for entire connection */
436 u32 rto_stamp; /* Start time (ms) of last CA_Loss recovery */
437 u16 total_rto; /* Total number of RTO timeouts, including
438 * SYN/SYN-ACK and recurring timeouts.
439 */
440 u16 total_rto_recoveries; /* Total number of RTO recoveries,
441 * including any unfinished recovery.
442 */
443 u32 total_rto_time; /* ms spent in (completed) RTO recoveries. */
444
445 u32 urg_seq; /* Seq of received urgent pointer */
446 unsigned int keepalive_time; /* time before keep alive takes place */
447 unsigned int keepalive_intvl; /* time interval between keep alive probes */
448
449 int linger2;
450
451
452/* Sock_ops bpf program related variables */
453#ifdef CONFIG_BPF
454 u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs
455 * values defined in uapi/linux/tcp.h
456 */
457 u8 bpf_chg_cc_inprogress:1; /* In the middle of
458 * bpf_setsockopt(TCP_CONGESTION),
459 * it is to avoid the bpf_tcp_cc->init()
460 * to recur itself by calling
461 * bpf_setsockopt(TCP_CONGESTION, "itself").
462 */
463#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG)
464#else
465#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0
466#endif
467
468 u16 timeout_rehash; /* Timeout-triggered rehash attempts */
469
470 u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */
471
472/* TCP-specific MTU probe information. */
473 struct {
474 u32 probe_seq_start;
475 u32 probe_seq_end;
476 } mtu_probe;
477 u32 plb_rehash; /* PLB-triggered rehash attempts */
478 u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
479 * while socket was owned by user.
480 */
481#if IS_ENABLED(CONFIG_MPTCP)
482 bool is_mptcp;
483#endif
484#if IS_ENABLED(CONFIG_SMC)
485 bool syn_smc; /* SYN includes SMC */
486 bool (*smc_hs_congested)(const struct sock *sk);
487#endif
488
489#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
490/* TCP AF-Specific parts; only used by TCP-AO/MD5 Signature support so far */
491 const struct tcp_sock_af_ops *af_specific;
492
493#ifdef CONFIG_TCP_MD5SIG
494/* TCP MD5 Signature Option information */
495 struct tcp_md5sig_info __rcu *md5sig_info;
496#endif
497#ifdef CONFIG_TCP_AO
498 struct tcp_ao_info __rcu *ao_info;
499#endif
500#endif
501
502/* TCP fastopen related information */
503 struct tcp_fastopen_request *fastopen_req;
504 /* fastopen_rsk points to request_sock that resulted in this big
505 * socket. Used to retransmit SYNACKs etc.
506 */
507 struct request_sock __rcu *fastopen_rsk;
508 struct saved_syn *saved_syn;
509};
510
511enum tsq_enum {
512 TSQ_THROTTLED,
513 TSQ_QUEUED,
514 TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */
515 TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */
516 TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */
517 TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call
518 * tcp_v{4|6}_mtu_reduced()
519 */
520 TCP_ACK_DEFERRED, /* TX pure ack is deferred */
521};
522
523enum tsq_flags {
524 TSQF_THROTTLED = BIT(TSQ_THROTTLED),
525 TSQF_QUEUED = BIT(TSQ_QUEUED),
526 TCPF_TSQ_DEFERRED = BIT(TCP_TSQ_DEFERRED),
527 TCPF_WRITE_TIMER_DEFERRED = BIT(TCP_WRITE_TIMER_DEFERRED),
528 TCPF_DELACK_TIMER_DEFERRED = BIT(TCP_DELACK_TIMER_DEFERRED),
529 TCPF_MTU_REDUCED_DEFERRED = BIT(TCP_MTU_REDUCED_DEFERRED),
530 TCPF_ACK_DEFERRED = BIT(TCP_ACK_DEFERRED),
531};
532
533#define tcp_sk(ptr) container_of_const(ptr, struct tcp_sock, inet_conn.icsk_inet.sk)
534
535/* Variant of tcp_sk() upgrading a const sock to a read/write tcp socket.
536 * Used in context of (lockless) tcp listeners.
537 */
538#define tcp_sk_rw(ptr) container_of(ptr, struct tcp_sock, inet_conn.icsk_inet.sk)
539
540struct tcp_timewait_sock {
541 struct inet_timewait_sock tw_sk;
542#define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt
543#define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt
544 u32 tw_rcv_wnd;
545 u32 tw_ts_offset;
546 u32 tw_ts_recent;
547
548 /* The time we sent the last out-of-window ACK: */
549 u32 tw_last_oow_ack_time;
550
551 int tw_ts_recent_stamp;
552 u32 tw_tx_delay;
553#ifdef CONFIG_TCP_MD5SIG
554 struct tcp_md5sig_key *tw_md5_key;
555#endif
556#ifdef CONFIG_TCP_AO
557 struct tcp_ao_info __rcu *ao_info;
558#endif
559};
560
561static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
562{
563 return (struct tcp_timewait_sock *)sk;
564}
565
566static inline bool tcp_passive_fastopen(const struct sock *sk)
567{
568 return sk->sk_state == TCP_SYN_RECV &&
569 rcu_access_pointer(tcp_sk(sk)->fastopen_rsk) != NULL;
570}
571
572static inline void fastopen_queue_tune(struct sock *sk, int backlog)
573{
574 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
575 int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn);
576
577 WRITE_ONCE(queue->fastopenq.max_qlen, min_t(unsigned int, backlog, somaxconn));
578}
579
580static inline void tcp_move_syn(struct tcp_sock *tp,
581 struct request_sock *req)
582{
583 tp->saved_syn = req->saved_syn;
584 req->saved_syn = NULL;
585}
586
587static inline void tcp_saved_syn_free(struct tcp_sock *tp)
588{
589 kfree(objp: tp->saved_syn);
590 tp->saved_syn = NULL;
591}
592
593static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn)
594{
595 return saved_syn->mac_hdrlen + saved_syn->network_hdrlen +
596 saved_syn->tcp_hdrlen;
597}
598
599struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
600 const struct sk_buff *orig_skb,
601 const struct sk_buff *ack_skb);
602
603static inline u16 tcp_mss_clamp(const struct tcp_sock *tp, u16 mss)
604{
605 /* We use READ_ONCE() here because socket might not be locked.
606 * This happens for listeners.
607 */
608 u16 user_mss = READ_ONCE(tp->rx_opt.user_mss);
609
610 return (user_mss && user_mss < mss) ? user_mss : mss;
611}
612
613int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
614 int shiftlen);
615
616void __tcp_sock_set_cork(struct sock *sk, bool on);
617void tcp_sock_set_cork(struct sock *sk, bool on);
618int tcp_sock_set_keepcnt(struct sock *sk, int val);
619int tcp_sock_set_keepidle_locked(struct sock *sk, int val);
620int tcp_sock_set_keepidle(struct sock *sk, int val);
621int tcp_sock_set_keepintvl(struct sock *sk, int val);
622void __tcp_sock_set_nodelay(struct sock *sk, bool on);
623void tcp_sock_set_nodelay(struct sock *sk);
624void tcp_sock_set_quickack(struct sock *sk, int val);
625int tcp_sock_set_syncnt(struct sock *sk, int val);
626int tcp_sock_set_user_timeout(struct sock *sk, int val);
627
628static inline bool dst_tcp_usec_ts(const struct dst_entry *dst)
629{
630 return dst_feature(dst, RTAX_FEATURE_TCP_USEC_TS);
631}
632
633#endif /* _LINUX_TCP_H */
634

source code of linux/include/linux/tcp.h

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