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 accecn:6, /* AccECN index in header, 0=no options */
126 saw_unknown:1, /* Received unknown option */
127 unused:1;
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
133static 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
148struct tcp_request_sock_ops;
149
150struct 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 bool req_usec_ts;
157#if IS_ENABLED(CONFIG_MPTCP)
158 bool drop_req;
159#endif
160 u32 txhash;
161 u32 rcv_isn;
162 u32 snt_isn;
163 u32 ts_off;
164 u32 snt_tsval_first;
165 u32 snt_tsval_last;
166 u32 last_oow_ack_time; /* last SYNACK */
167 u32 rcv_nxt; /* the ack # by SYNACK. For
168 * FastOpen it's the seq#
169 * after data-in-SYN.
170 */
171 u8 syn_tos;
172 bool accecn_ok;
173 u8 syn_ect_snt: 2,
174 syn_ect_rcv: 2,
175 accecn_fail_mode:4;
176 u8 saw_accecn_opt :2;
177#ifdef CONFIG_TCP_AO
178 u8 ao_keyid;
179 u8 ao_rcv_next;
180 bool used_tcp_ao;
181#endif
182};
183
184static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
185{
186 return (struct tcp_request_sock *)req;
187}
188
189static inline bool tcp_rsk_used_ao(const struct request_sock *req)
190{
191#ifndef CONFIG_TCP_AO
192 return false;
193#else
194 return tcp_rsk(req)->used_tcp_ao;
195#endif
196}
197
198#define TCP_RMEM_TO_WIN_SCALE 8
199
200struct tcp_sock {
201 /* Cacheline organization can be found documented in
202 * Documentation/networking/net_cachelines/tcp_sock.rst.
203 * Please update the document when adding new fields.
204 */
205
206 /* inet_connection_sock has to be the first member of tcp_sock */
207 struct inet_connection_sock inet_conn;
208
209 /* TX read-mostly hotpath cache lines */
210 __cacheline_group_begin(tcp_sock_read_tx);
211 u32 max_window; /* Maximal window ever seen from peer */
212 u32 rcv_ssthresh; /* Current window clamp */
213 u32 reordering; /* Packet reordering metric. */
214 u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */
215 u16 gso_segs; /* Max number of segs per GSO packet */
216 /* from STCP, retrans queue hinting */
217 struct sk_buff *retransmit_skb_hint;
218#if defined(CONFIG_TLS_DEVICE)
219 void (*tcp_clean_acked)(struct sock *sk, u32 acked_seq);
220#endif
221 __cacheline_group_end(tcp_sock_read_tx);
222
223 /* TXRX read-mostly hotpath cache lines */
224 __cacheline_group_begin(tcp_sock_read_txrx);
225 u32 tsoffset; /* timestamp offset */
226 u32 snd_wnd; /* The window we expect to receive */
227 u32 mss_cache; /* Cached effective mss, not including SACKS */
228 u32 snd_cwnd; /* Sending congestion window */
229 u32 prr_out; /* Total number of pkts sent during Recovery. */
230 u32 lost_out; /* Lost packets */
231 u32 sacked_out; /* SACK'd packets */
232 u16 tcp_header_len; /* Bytes of tcp header to send */
233 u8 scaling_ratio; /* see tcp_win_from_space() */
234 u8 chrono_type : 2, /* current chronograph type */
235 repair : 1,
236 tcp_usec_ts : 1, /* TSval values in usec */
237 is_sack_reneg:1, /* in recovery from loss with SACK reneg? */
238 is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */
239 recvmsg_inq : 1;/* Indicate # of bytes in queue upon recvmsg */
240 __cacheline_group_end(tcp_sock_read_txrx);
241
242 /* RX read-mostly hotpath cache lines */
243 __cacheline_group_begin(tcp_sock_read_rx);
244 u32 copied_seq; /* Head of yet unread data */
245 u32 snd_wl1; /* Sequence for window update */
246 u32 tlp_high_seq; /* snd_nxt at the time of TLP */
247 u32 rttvar_us; /* smoothed mdev_max */
248 u32 retrans_out; /* Retransmitted packets out */
249 u16 advmss; /* Advertised MSS */
250 u16 urg_data; /* Saved octet of OOB data and control flags */
251 u32 lost; /* Total data packets lost incl. rexmits */
252 u32 snd_ssthresh; /* Slow start size threshold */
253 struct minmax rtt_min;
254 /* OOO segments go in this rbtree. Socket lock must be held. */
255 struct rb_root out_of_order_queue;
256 __cacheline_group_end(tcp_sock_read_rx);
257
258 /* TX read-write hotpath cache lines */
259 __cacheline_group_begin(tcp_sock_write_tx) ____cacheline_aligned;
260 u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
261 * The total number of segments sent.
262 */
263 u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
264 * total number of data segments sent.
265 */
266 u64 bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut
267 * total number of data bytes sent.
268 */
269 u32 snd_sml; /* Last byte of the most recently transmitted small packet */
270 u32 chrono_start; /* Start time in jiffies of a TCP chrono */
271 u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */
272 u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
273 u32 pushed_seq; /* Last pushed seq, required to talk to windows */
274 u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
275 u32 mdev_us; /* medium deviation */
276 u32 rtt_seq; /* sequence number to update rttvar */
277 u64 tcp_wstamp_ns; /* departure time for next sent data packet */
278 u64 accecn_opt_tstamp; /* Last AccECN option sent timestamp */
279 struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */
280 struct sk_buff *highest_sack; /* skb just after the highest
281 * skb with SACKed bit set
282 * (validity guaranteed only if
283 * sacked_out > 0)
284 */
285 u8 ecn_flags; /* ECN status bits. */
286 __cacheline_group_end(tcp_sock_write_tx);
287
288 /* TXRX read-write hotpath cache lines */
289 __cacheline_group_begin(tcp_sock_write_txrx);
290/*
291 * Header prediction flags
292 * 0x5?10 << 16 + snd_wnd in net byte order
293 */
294 u8 nonagle : 4,/* Disable Nagle algorithm? */
295 rate_app_limited:1; /* rate_{delivered,interval_us} limited? */
296 u8 received_ce_pending:4, /* Not yet transmit cnt of received_ce */
297 unused2:4;
298 u8 accecn_minlen:2,/* Minimum length of AccECN option sent */
299 est_ecnfield:2,/* ECN field for AccECN delivered estimates */
300 accecn_opt_demand:2,/* Demand AccECN option for n next ACKs */
301 prev_ecnfield:2; /* ECN bits from the previous segment */
302 __be32 pred_flags;
303 u64 tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */
304 u64 tcp_mstamp; /* most recent packet received/sent */
305 u32 rcv_nxt; /* What we want to receive next */
306 u32 snd_nxt; /* Next sequence we send */
307 u32 snd_una; /* First byte we want an ack for */
308 u32 window_clamp; /* Maximal window to advertise */
309 u32 srtt_us; /* smoothed round trip time << 3 in usecs */
310 u32 packets_out; /* Packets which are "in flight" */
311 u32 snd_up; /* Urgent pointer */
312 u32 delivered; /* Total data packets delivered incl. rexmits */
313 u32 delivered_ce; /* Like the above but only ECE marked packets */
314 u32 received_ce; /* Like the above but for rcvd CE marked pkts */
315 u32 received_ecn_bytes[3]; /* received byte counters for three ECN
316 * types: INET_ECN_ECT_1, INET_ECN_ECT_0,
317 * and INET_ECN_CE
318 */
319 u32 app_limited; /* limited until "delivered" reaches this val */
320 u32 rcv_wnd; /* Current receiver window */
321 u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
322/*
323 * Options received (usually on last packet, some only on SYN packets).
324 */
325 struct tcp_options_received rx_opt;
326 __cacheline_group_end(tcp_sock_write_txrx);
327
328 /* RX read-write hotpath cache lines */
329 __cacheline_group_begin(tcp_sock_write_rx) __aligned(8);
330 u64 bytes_received;
331 /* RFC4898 tcpEStatsAppHCThruOctetsReceived
332 * sum(delta(rcv_nxt)), or how many bytes
333 * were acked.
334 */
335 u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
336 * total number of segments in.
337 */
338 u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
339 * total number of data segments in.
340 */
341 u32 rcv_wup; /* rcv_nxt on last window update sent */
342 u32 max_packets_out; /* max packets_out in last window */
343 u32 cwnd_usage_seq; /* right edge of cwnd usage tracking flight */
344 u32 rate_delivered; /* saved rate sample: packets delivered */
345 u32 rate_interval_us; /* saved rate sample: time elapsed */
346 u32 rcv_rtt_last_tsecr;
347 u32 delivered_ecn_bytes[3];
348 u64 first_tx_mstamp; /* start of window send phase */
349 u64 delivered_mstamp; /* time we reached "delivered" */
350 u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
351 * sum(delta(snd_una)), or how many bytes
352 * were acked.
353 */
354 struct {
355 u32 rtt_us;
356 u32 seq;
357 u64 time;
358 } rcv_rtt_est;
359/* Receiver queue space */
360 struct {
361 int space;
362 u32 seq;
363 u64 time;
364 } rcvq_space;
365 __cacheline_group_end(tcp_sock_write_rx);
366 /* End of Hot Path */
367
368/*
369 * RFC793 variables by their proper names. This means you can
370 * read the code and the spec side by side (and laugh ...)
371 * See RFC793 and RFC1122. The RFC writes these in capitals.
372 */
373 u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
374 * total number of DSACK blocks received
375 */
376 u32 compressed_ack_rcv_nxt;
377 struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
378
379 /* Information of the most recently (s)acked skb */
380 struct tcp_rack {
381 u64 mstamp; /* (Re)sent time of the skb */
382 u32 rtt_us; /* Associated RTT */
383 u32 end_seq; /* Ending TCP sequence of the skb */
384 u32 last_delivered; /* tp->delivered at last reo_wnd adj */
385 u8 reo_wnd_steps; /* Allowed reordering window */
386#define TCP_RACK_RECOVERY_THRESH 16
387 u8 reo_wnd_persist:5, /* No. of recovery since last adj */
388 dsack_seen:1, /* Whether DSACK seen after last adj */
389 advanced:1; /* mstamp advanced since last lost marking */
390 } rack;
391 u8 compressed_ack;
392 u8 dup_ack_counter:2,
393 tlp_retrans:1, /* TLP is a retransmission */
394 syn_ect_snt:2, /* AccECN ECT memory, only */
395 syn_ect_rcv:2; /* ... needed during 3WHS + first seqno */
396 u8 thin_lto : 1,/* Use linear timeouts for thin streams */
397 fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */
398 fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */
399 fastopen_client_fail:2, /* reason why fastopen failed */
400 frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */
401 u8 repair_queue;
402 u8 save_syn:2, /* Save headers of SYN packet */
403 syn_data:1, /* SYN includes data */
404 syn_fastopen:1, /* SYN includes Fast Open option */
405 syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
406 syn_fastopen_ch:1, /* Active TFO re-enabling probe */
407 syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
408 syn_fastopen_child:1; /* created TFO passive child socket */
409
410 u8 keepalive_probes; /* num of allowed keep alive probes */
411 u8 accecn_fail_mode:4, /* AccECN failure handling */
412 saw_accecn_opt:2; /* An AccECN option was seen */
413 u32 tcp_tx_delay; /* delay (in usec) added to TX packets */
414
415/* RTT measurement */
416 u32 mdev_max_us; /* maximal mdev for the last rtt period */
417
418 u32 reord_seen; /* number of data packet reordering events */
419
420/*
421 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
422 */
423 u32 snd_cwnd_cnt; /* Linear increase counter */
424 u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
425 u32 snd_cwnd_used;
426 u32 snd_cwnd_stamp;
427 u32 prior_cwnd; /* cwnd right before starting loss recovery */
428 u32 prr_delivered; /* Number of newly delivered packets to
429 * receiver in Recovery. */
430 u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */
431
432 struct hrtimer pacing_timer;
433 struct hrtimer compressed_ack_timer;
434
435 struct sk_buff *ooo_last_skb; /* cache rb_last(out_of_order_queue) */
436
437 /* SACKs data, these 2 need to be together (see tcp_options_write) */
438 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
439 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
440
441 struct tcp_sack_block recv_sack_cache[4];
442
443 u32 prior_ssthresh; /* ssthresh saved at recovery start */
444 u32 high_seq; /* snd_nxt at onset of congestion */
445
446 u32 retrans_stamp; /* Timestamp of the last retransmit,
447 * also used in SYN-SENT to remember stamp of
448 * the first SYN. */
449 u32 undo_marker; /* snd_una upon a new recovery episode. */
450 int undo_retrans; /* number of undoable retransmissions. */
451 u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
452 * while socket was owned by user.
453 */
454 u64 bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans
455 * Total data bytes retransmitted
456 */
457 u32 total_retrans; /* Total retransmits for entire connection */
458 u32 rto_stamp; /* Start time (ms) of last CA_Loss recovery */
459 u16 total_rto; /* Total number of RTO timeouts, including
460 * SYN/SYN-ACK and recurring timeouts.
461 */
462 u16 total_rto_recoveries; /* Total number of RTO recoveries,
463 * including any unfinished recovery.
464 */
465 u32 total_rto_time; /* ms spent in (completed) RTO recoveries. */
466
467 u32 urg_seq; /* Seq of received urgent pointer */
468 unsigned int keepalive_time; /* time before keep alive takes place */
469 unsigned int keepalive_intvl; /* time interval between keep alive probes */
470
471 int linger2;
472
473
474/* Sock_ops bpf program related variables */
475#ifdef CONFIG_BPF
476 u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs
477 * values defined in uapi/linux/tcp.h
478 */
479 u8 bpf_chg_cc_inprogress:1; /* In the middle of
480 * bpf_setsockopt(TCP_CONGESTION),
481 * it is to avoid the bpf_tcp_cc->init()
482 * to recur itself by calling
483 * bpf_setsockopt(TCP_CONGESTION, "itself").
484 */
485#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG)
486#else
487#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0
488#endif
489
490 u16 timeout_rehash; /* Timeout-triggered rehash attempts */
491
492 u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */
493
494/* TCP-specific MTU probe information. */
495 struct {
496 u32 probe_seq_start;
497 u32 probe_seq_end;
498 } mtu_probe;
499 u32 plb_rehash; /* PLB-triggered rehash attempts */
500#if IS_ENABLED(CONFIG_MPTCP)
501 bool is_mptcp;
502#endif
503#if IS_ENABLED(CONFIG_SMC)
504 bool syn_smc; /* SYN includes SMC */
505 bool (*smc_hs_congested)(const struct sock *sk);
506#endif
507
508#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
509/* TCP AF-Specific parts; only used by TCP-AO/MD5 Signature support so far */
510 const struct tcp_sock_af_ops *af_specific;
511
512#ifdef CONFIG_TCP_MD5SIG
513/* TCP MD5 Signature Option information */
514 struct tcp_md5sig_info __rcu *md5sig_info;
515#endif
516#ifdef CONFIG_TCP_AO
517 struct tcp_ao_info __rcu *ao_info;
518#endif
519#endif
520
521/* TCP fastopen related information */
522 struct tcp_fastopen_request *fastopen_req;
523 /* fastopen_rsk points to request_sock that resulted in this big
524 * socket. Used to retransmit SYNACKs etc.
525 */
526 struct request_sock __rcu *fastopen_rsk;
527 struct saved_syn *saved_syn;
528};
529
530enum tsq_enum {
531 TSQ_THROTTLED,
532 TSQ_QUEUED,
533 TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */
534 TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */
535 TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */
536 TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call
537 * tcp_v{4|6}_mtu_reduced()
538 */
539 TCP_ACK_DEFERRED, /* TX pure ack is deferred */
540};
541
542enum tsq_flags {
543 TSQF_THROTTLED = BIT(TSQ_THROTTLED),
544 TSQF_QUEUED = BIT(TSQ_QUEUED),
545 TCPF_TSQ_DEFERRED = BIT(TCP_TSQ_DEFERRED),
546 TCPF_WRITE_TIMER_DEFERRED = BIT(TCP_WRITE_TIMER_DEFERRED),
547 TCPF_DELACK_TIMER_DEFERRED = BIT(TCP_DELACK_TIMER_DEFERRED),
548 TCPF_MTU_REDUCED_DEFERRED = BIT(TCP_MTU_REDUCED_DEFERRED),
549 TCPF_ACK_DEFERRED = BIT(TCP_ACK_DEFERRED),
550};
551
552#define tcp_sk(ptr) container_of_const(ptr, struct tcp_sock, inet_conn.icsk_inet.sk)
553
554/* Variant of tcp_sk() upgrading a const sock to a read/write tcp socket.
555 * Used in context of (lockless) tcp listeners.
556 */
557#define tcp_sk_rw(ptr) container_of(ptr, struct tcp_sock, inet_conn.icsk_inet.sk)
558
559struct tcp_timewait_sock {
560 struct inet_timewait_sock tw_sk;
561#define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt
562#define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt
563 u32 tw_rcv_wnd;
564 u32 tw_ts_offset;
565 u32 tw_ts_recent;
566
567 /* The time we sent the last out-of-window ACK: */
568 u32 tw_last_oow_ack_time;
569
570 int tw_ts_recent_stamp;
571 u32 tw_tx_delay;
572#ifdef CONFIG_TCP_MD5SIG
573 struct tcp_md5sig_key *tw_md5_key;
574#endif
575#ifdef CONFIG_TCP_AO
576 struct tcp_ao_info __rcu *ao_info;
577#endif
578};
579
580static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
581{
582 return (struct tcp_timewait_sock *)sk;
583}
584
585static inline bool tcp_passive_fastopen(const struct sock *sk)
586{
587 return sk->sk_state == TCP_SYN_RECV &&
588 rcu_access_pointer(tcp_sk(sk)->fastopen_rsk) != NULL;
589}
590
591static inline void fastopen_queue_tune(struct sock *sk, int backlog)
592{
593 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
594 int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn);
595
596 WRITE_ONCE(queue->fastopenq.max_qlen, min_t(unsigned int, backlog, somaxconn));
597}
598
599static inline void tcp_move_syn(struct tcp_sock *tp,
600 struct request_sock *req)
601{
602 tp->saved_syn = req->saved_syn;
603 req->saved_syn = NULL;
604}
605
606static inline void tcp_saved_syn_free(struct tcp_sock *tp)
607{
608 kfree(objp: tp->saved_syn);
609 tp->saved_syn = NULL;
610}
611
612static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn)
613{
614 return saved_syn->mac_hdrlen + saved_syn->network_hdrlen +
615 saved_syn->tcp_hdrlen;
616}
617
618struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
619 const struct sk_buff *orig_skb,
620 const struct sk_buff *ack_skb);
621
622static inline u16 tcp_mss_clamp(const struct tcp_sock *tp, u16 mss)
623{
624 /* We use READ_ONCE() here because socket might not be locked.
625 * This happens for listeners.
626 */
627 u16 user_mss = READ_ONCE(tp->rx_opt.user_mss);
628
629 return (user_mss && user_mss < mss) ? user_mss : mss;
630}
631
632int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
633 int shiftlen);
634
635void __tcp_sock_set_cork(struct sock *sk, bool on);
636void tcp_sock_set_cork(struct sock *sk, bool on);
637int tcp_sock_set_keepcnt(struct sock *sk, int val);
638int tcp_sock_set_keepidle_locked(struct sock *sk, int val);
639int tcp_sock_set_keepidle(struct sock *sk, int val);
640int tcp_sock_set_keepintvl(struct sock *sk, int val);
641void __tcp_sock_set_nodelay(struct sock *sk, bool on);
642void tcp_sock_set_nodelay(struct sock *sk);
643void tcp_sock_set_quickack(struct sock *sk, int val);
644int tcp_sock_set_syncnt(struct sock *sk, int val);
645int tcp_sock_set_user_timeout(struct sock *sk, int val);
646int tcp_sock_set_maxseg(struct sock *sk, int val);
647
648static inline bool dst_tcp_usec_ts(const struct dst_entry *dst)
649{
650 return dst_feature(dst, RTAX_FEATURE_TCP_USEC_TS);
651}
652
653#endif /* _LINUX_TCP_H */
654