Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
3 | * operating system. INET is implemented using the BSD Socket | |
4 | * interface as the means of communication with the user level. | |
5 | * | |
6 | * Definitions for the TCP protocol. | |
7 | * | |
8 | * Version: @(#)tcp.h 1.0.2 04/28/93 | |
9 | * | |
10 | * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version | |
15 | * 2 of the License, or (at your option) any later version. | |
16 | */ | |
17 | #ifndef _LINUX_TCP_H | |
18 | #define _LINUX_TCP_H | |
19 | ||
1da177e4 | 20 | |
1da177e4 | 21 | #include <linux/skbuff.h> |
1da177e4 | 22 | #include <net/sock.h> |
463c84b9 | 23 | #include <net/inet_connection_sock.h> |
8feaf0c0 | 24 | #include <net/inet_timewait_sock.h> |
607ca46e | 25 | #include <uapi/linux/tcp.h> |
1da177e4 | 26 | |
aa8223c7 ACM |
27 | static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb) |
28 | { | |
9c70220b | 29 | return (struct tcphdr *)skb_transport_header(skb); |
aa8223c7 ACM |
30 | } |
31 | ||
ab6a5bb6 ACM |
32 | static inline unsigned int tcp_hdrlen(const struct sk_buff *skb) |
33 | { | |
aa8223c7 | 34 | return tcp_hdr(skb)->doff * 4; |
ab6a5bb6 ACM |
35 | } |
36 | ||
6a674e9c JG |
37 | static inline struct tcphdr *inner_tcp_hdr(const struct sk_buff *skb) |
38 | { | |
39 | return (struct tcphdr *)skb_inner_transport_header(skb); | |
40 | } | |
41 | ||
42 | static inline unsigned int inner_tcp_hdrlen(const struct sk_buff *skb) | |
43 | { | |
44 | return inner_tcp_hdr(skb)->doff * 4; | |
45 | } | |
46 | ||
ab6a5bb6 ACM |
47 | static inline unsigned int tcp_optlen(const struct sk_buff *skb) |
48 | { | |
aa8223c7 | 49 | return (tcp_hdr(skb)->doff - 5) * 4; |
ab6a5bb6 ACM |
50 | } |
51 | ||
2100c8d2 YC |
52 | /* TCP Fast Open */ |
53 | #define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */ | |
54 | #define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */ | |
10467163 | 55 | #define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */ |
2100c8d2 YC |
56 | |
57 | /* TCP Fast Open Cookie as stored in memory */ | |
58 | struct tcp_fastopen_cookie { | |
59 | s8 len; | |
60 | u8 val[TCP_FASTOPEN_COOKIE_MAX]; | |
7f9b838b | 61 | bool exp; /* In RFC6994 experimental option format */ |
2100c8d2 YC |
62 | }; |
63 | ||
1da177e4 | 64 | /* This defines a selective acknowledgement block. */ |
269bd27e AV |
65 | struct tcp_sack_block_wire { |
66 | __be32 start_seq; | |
67 | __be32 end_seq; | |
68 | }; | |
69 | ||
1da177e4 | 70 | struct tcp_sack_block { |
3a137d20 ACM |
71 | u32 start_seq; |
72 | u32 end_seq; | |
1da177e4 LT |
73 | }; |
74 | ||
ab56222a VS |
75 | /*These are used to set the sack_ok field in struct tcp_options_received */ |
76 | #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */ | |
77 | #define TCP_FACK_ENABLED (1 << 1) /*1 = FACK is enabled locally*/ | |
78 | #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ | |
79 | ||
1da177e4 LT |
80 | struct tcp_options_received { |
81 | /* PAWS/RTTM data */ | |
82 | long ts_recent_stamp;/* Time we stored ts_recent (for aging) */ | |
3a137d20 ACM |
83 | u32 ts_recent; /* Time stamp to echo next */ |
84 | u32 rcv_tsval; /* Time stamp value */ | |
85 | u32 rcv_tsecr; /* Time stamp echo reply */ | |
86 | u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ | |
1da177e4 LT |
87 | tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ |
88 | dsack : 1, /* D-SACK is scheduled */ | |
89 | wscale_ok : 1, /* Wscale seen on SYN packet */ | |
90 | sack_ok : 4, /* SACK seen on SYN packet */ | |
91 | snd_wscale : 4, /* Window scaling received from sender */ | |
92 | rcv_wscale : 4; /* Window scaling to send to receiver */ | |
3a137d20 | 93 | u8 num_sacks; /* Number of SACK blocks */ |
435cf559 | 94 | u16 user_mss; /* mss requested by user in ioctl */ |
3a137d20 | 95 | u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ |
1da177e4 LT |
96 | }; |
97 | ||
519855c5 WAS |
98 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) |
99 | { | |
435cf559 WAS |
100 | rx_opt->tstamp_ok = rx_opt->sack_ok = 0; |
101 | rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
519855c5 WAS |
102 | } |
103 | ||
4389dded | 104 | /* This is the max number of SACKS that we'll generate and process. It's safe |
435cf559 | 105 | * to increase this, although since: |
4389dded AL |
106 | * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) |
107 | * only four options will fit in a standard TCP header */ | |
108 | #define TCP_NUM_SACKS 4 | |
109 | ||
435cf559 WAS |
110 | struct tcp_request_sock_ops; |
111 | ||
2e6599cb | 112 | struct tcp_request_sock { |
cfb6eeb4 | 113 | struct inet_request_sock req; |
b2e4b3de | 114 | const struct tcp_request_sock_ops *af_specific; |
0f1c28ae | 115 | struct skb_mstamp snt_synack; /* first SYNACK sent time */ |
9439ce00 | 116 | bool tfo_listener; |
58d607d3 | 117 | u32 txhash; |
435cf559 WAS |
118 | u32 rcv_isn; |
119 | u32 snt_isn; | |
a9b2c06d | 120 | u32 last_oow_ack_time; /* last SYNACK */ |
10467163 JC |
121 | u32 rcv_nxt; /* the ack # by SYNACK. For |
122 | * FastOpen it's the seq# | |
123 | * after data-in-SYN. | |
124 | */ | |
2e6599cb ACM |
125 | }; |
126 | ||
60236fdd | 127 | static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) |
2e6599cb ACM |
128 | { |
129 | return (struct tcp_request_sock *)req; | |
130 | } | |
131 | ||
1da177e4 | 132 | struct tcp_sock { |
463c84b9 ACM |
133 | /* inet_connection_sock has to be the first member of tcp_sock */ |
134 | struct inet_connection_sock inet_conn; | |
2ff52f28 | 135 | u16 tcp_header_len; /* Bytes of tcp header to send */ |
605ad7f1 | 136 | u16 gso_segs; /* Max number of segs per GSO packet */ |
1da177e4 LT |
137 | |
138 | /* | |
139 | * Header prediction flags | |
140 | * 0x5?10 << 16 + snd_wnd in net byte order | |
141 | */ | |
dddc93c0 | 142 | __be32 pred_flags; |
1da177e4 LT |
143 | |
144 | /* | |
145 | * RFC793 variables by their proper names. This means you can | |
146 | * read the code and the spec side by side (and laugh ...) | |
147 | * See RFC793 and RFC1122. The RFC writes these in capitals. | |
148 | */ | |
bdd1f9ed ED |
149 | u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived |
150 | * sum(delta(rcv_nxt)), or how many bytes | |
151 | * were acked. | |
152 | */ | |
2efd055c MRL |
153 | u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn |
154 | * total number of segments in. | |
155 | */ | |
3a137d20 | 156 | u32 rcv_nxt; /* What we want to receive next */ |
54287cc1 ED |
157 | u32 copied_seq; /* Head of yet unread data */ |
158 | u32 rcv_wup; /* rcv_nxt on last window update sent */ | |
3a137d20 | 159 | u32 snd_nxt; /* Next sequence we send */ |
2efd055c MRL |
160 | u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut |
161 | * The total number of segments sent. | |
162 | */ | |
0df48c26 ED |
163 | u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked |
164 | * sum(delta(snd_una)), or how many bytes | |
165 | * were acked. | |
166 | */ | |
d654976c ED |
167 | struct u64_stats_sync syncp; /* protects 64bit vars (cf tcp_get_info()) */ |
168 | ||
3a137d20 ACM |
169 | u32 snd_una; /* First byte we want an ack for */ |
170 | u32 snd_sml; /* Last byte of the most recently transmitted small packet */ | |
171 | u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ | |
172 | u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ | |
f2b2c582 | 173 | u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */ |
1da177e4 | 174 | |
ceaa1fef AV |
175 | u32 tsoffset; /* timestamp offset */ |
176 | ||
46d3ceab ED |
177 | struct list_head tsq_node; /* anchor in tsq_tasklet.head list */ |
178 | unsigned long tsq_flags; | |
179 | ||
1da177e4 LT |
180 | /* Data for direct copy to user */ |
181 | struct { | |
182 | struct sk_buff_head prequeue; | |
183 | struct task_struct *task; | |
f4362a2c | 184 | struct msghdr *msg; |
1da177e4 LT |
185 | int memory; |
186 | int len; | |
187 | } ucopy; | |
188 | ||
3a137d20 ACM |
189 | u32 snd_wl1; /* Sequence for window update */ |
190 | u32 snd_wnd; /* The window we expect to receive */ | |
191 | u32 max_window; /* Maximal window ever seen from peer */ | |
192 | u32 mss_cache; /* Cached effective mss, not including SACKS */ | |
1da177e4 | 193 | |
3a137d20 ACM |
194 | u32 window_clamp; /* Maximal window to advertise */ |
195 | u32 rcv_ssthresh; /* Current window clamp */ | |
1da177e4 | 196 | |
659a8ad5 YC |
197 | /* Information of the most recently (s)acked skb */ |
198 | struct tcp_rack { | |
199 | struct skb_mstamp mstamp; /* (Re)sent time of the skb */ | |
200 | u8 advanced; /* mstamp advanced since last lost marking */ | |
201 | u8 reord; /* reordering detected */ | |
202 | } rack; | |
b79eeeb9 | 203 | u16 advmss; /* Advertised MSS */ |
9b44190d | 204 | u8 unused; |
36e31b0a AP |
205 | u8 nonagle : 4,/* Disable Nagle algorithm? */ |
206 | thin_lto : 1,/* Use linear timeouts for thin streams */ | |
7e380175 | 207 | thin_dupack : 1,/* Fast retransmit on first dupack */ |
e33099f9 YC |
208 | repair : 1, |
209 | frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */ | |
ee995283 | 210 | u8 repair_queue; |
750ea2ba | 211 | u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */ |
67da22d2 | 212 | syn_data:1, /* SYN includes data */ |
6f73601e | 213 | syn_fastopen:1, /* SYN includes Fast Open option */ |
2646c831 | 214 | syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */ |
ca8a2263 | 215 | syn_data_acked:1,/* data in SYN is acked by SYN-ACK */ |
cd8ae852 | 216 | save_syn:1, /* Save headers of SYN packet */ |
ca8a2263 | 217 | is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */ |
9b717a8d | 218 | u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */ |
1da177e4 LT |
219 | |
220 | /* RTT measurement */ | |
740b0f18 ED |
221 | u32 srtt_us; /* smoothed round trip time << 3 in usecs */ |
222 | u32 mdev_us; /* medium deviation */ | |
223 | u32 mdev_max_us; /* maximal mdev for the last rtt period */ | |
224 | u32 rttvar_us; /* smoothed mdev_max */ | |
3a137d20 | 225 | u32 rtt_seq; /* sequence number to update rttvar */ |
f6722583 YC |
226 | struct rtt_meas { |
227 | u32 rtt, ts; /* RTT in usec and sampling time in jiffies. */ | |
228 | } rtt_min[3]; | |
3a137d20 ACM |
229 | |
230 | u32 packets_out; /* Packets which are "in flight" */ | |
3a137d20 | 231 | u32 retrans_out; /* Retransmitted packets out */ |
ca8a2263 NC |
232 | u32 max_packets_out; /* max packets_out in last window */ |
233 | u32 max_packets_seq; /* right edge of max_packets_out flight */ | |
b79eeeb9 IJ |
234 | |
235 | u16 urg_data; /* Saved octet of OOB data and control flags */ | |
b79eeeb9 | 236 | u8 ecn_flags; /* ECN status bits. */ |
dca145ff ED |
237 | u8 keepalive_probes; /* num of allowed keep alive probes */ |
238 | u32 reordering; /* Packet reordering metric. */ | |
33f5f57e IJ |
239 | u32 snd_up; /* Urgent pointer */ |
240 | ||
1da177e4 LT |
241 | /* |
242 | * Options received (usually on last packet, some only on SYN packets). | |
243 | */ | |
1da177e4 LT |
244 | struct tcp_options_received rx_opt; |
245 | ||
246 | /* | |
247 | * Slow start and congestion control (see also Nagle, and Karn & Partridge) | |
248 | */ | |
3a137d20 ACM |
249 | u32 snd_ssthresh; /* Slow start size threshold */ |
250 | u32 snd_cwnd; /* Sending congestion window */ | |
f78a1b38 | 251 | u32 snd_cwnd_cnt; /* Linear increase counter */ |
e0ef57cc | 252 | u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ |
3a137d20 ACM |
253 | u32 snd_cwnd_used; |
254 | u32 snd_cwnd_stamp; | |
a262f0cd ND |
255 | u32 prior_cwnd; /* Congestion window at start of Recovery. */ |
256 | u32 prr_delivered; /* Number of newly delivered packets to | |
257 | * receiver in Recovery. */ | |
258 | u32 prr_out; /* Total number of pkts sent during Recovery. */ | |
1da177e4 | 259 | |
3a137d20 | 260 | u32 rcv_wnd; /* Current receiver window */ |
3a137d20 | 261 | u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ |
c9bee3b7 | 262 | u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */ |
3a137d20 | 263 | u32 pushed_seq; /* Last pushed seq, required to talk to windows */ |
b79eeeb9 IJ |
264 | u32 lost_out; /* Lost packets */ |
265 | u32 sacked_out; /* SACK'd packets */ | |
266 | u32 fackets_out; /* FACK'd packets */ | |
1da177e4 | 267 | |
b79eeeb9 IJ |
268 | /* from STCP, retrans queue hinting */ |
269 | struct sk_buff* lost_skb_hint; | |
b79eeeb9 | 270 | struct sk_buff *retransmit_skb_hint; |
b79eeeb9 | 271 | |
996b175e ED |
272 | /* OOO segments go in this list. Note that socket lock must be held, |
273 | * as we do not use sk_buff_head lock. | |
274 | */ | |
275 | struct sk_buff_head out_of_order_queue; | |
b79eeeb9 | 276 | |
c0a788c4 | 277 | /* SACKs data, these 2 need to be together (see tcp_options_write) */ |
1da177e4 LT |
278 | struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ |
279 | struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ | |
280 | ||
fd6dad61 | 281 | struct tcp_sack_block recv_sack_cache[4]; |
6a438bbe | 282 | |
ecb97192 NC |
283 | struct sk_buff *highest_sack; /* skb just after the highest |
284 | * skb with SACKed bit set | |
a47e5a98 IJ |
285 | * (validity guaranteed only if |
286 | * sacked_out > 0) | |
287 | */ | |
d738cd8f | 288 | |
6a438bbe | 289 | int lost_cnt_hint; |
006f582c | 290 | u32 retransmit_high; /* L-bits may be on up to this seqno */ |
6a438bbe | 291 | |
4b749440 | 292 | u32 prior_ssthresh; /* ssthresh saved at recovery start */ |
3a137d20 | 293 | u32 high_seq; /* snd_nxt at onset of congestion */ |
1da177e4 | 294 | |
3a137d20 | 295 | u32 retrans_stamp; /* Timestamp of the last retransmit, |
1da177e4 LT |
296 | * also used in SYN-SENT to remember stamp of |
297 | * the first SYN. */ | |
989e04c5 | 298 | u32 undo_marker; /* snd_una upon a new recovery episode. */ |
1da177e4 | 299 | int undo_retrans; /* number of undoable retransmissions. */ |
b79eeeb9 IJ |
300 | u32 total_retrans; /* Total retransmits for entire connection */ |
301 | ||
3a137d20 | 302 | u32 urg_seq; /* Seq of received urgent pointer */ |
1da177e4 LT |
303 | unsigned int keepalive_time; /* time before keep alive takes place */ |
304 | unsigned int keepalive_intvl; /* time interval between keep alive probes */ | |
1da177e4 | 305 | |
a0f82f64 | 306 | int linger2; |
1da177e4 LT |
307 | |
308 | /* Receiver side RTT estimation */ | |
309 | struct { | |
3a137d20 ACM |
310 | u32 rtt; |
311 | u32 seq; | |
312 | u32 time; | |
1da177e4 LT |
313 | } rcv_rtt_est; |
314 | ||
315 | /* Receiver queue space */ | |
316 | struct { | |
317 | int space; | |
3a137d20 ACM |
318 | u32 seq; |
319 | u32 time; | |
1da177e4 | 320 | } rcvq_space; |
0e7b1368 JH |
321 | |
322 | /* TCP-specific MTU probe information. */ | |
323 | struct { | |
3a137d20 ACM |
324 | u32 probe_seq_start; |
325 | u32 probe_seq_end; | |
0e7b1368 | 326 | } mtu_probe; |
563d34d0 ED |
327 | u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG |
328 | * while socket was owned by user. | |
329 | */ | |
cfb6eeb4 YH |
330 | |
331 | #ifdef CONFIG_TCP_MD5SIG | |
332 | /* TCP AF-Specific parts; only used by MD5 Signature support so far */ | |
b2e4b3de | 333 | const struct tcp_sock_af_ops *af_specific; |
cfb6eeb4 | 334 | |
b2e4b3de | 335 | /* TCP MD5 Signature Option information */ |
a8afca03 | 336 | struct tcp_md5sig_info __rcu *md5sig_info; |
cfb6eeb4 | 337 | #endif |
435cf559 | 338 | |
10467163 JC |
339 | /* TCP fastopen related information */ |
340 | struct tcp_fastopen_request *fastopen_req; | |
341 | /* fastopen_rsk points to request_sock that resulted in this big | |
342 | * socket. Used to retransmit SYNACKs etc. | |
343 | */ | |
344 | struct request_sock *fastopen_rsk; | |
cd8ae852 | 345 | u32 *saved_syn; |
1da177e4 LT |
346 | }; |
347 | ||
46d3ceab ED |
348 | enum tsq_flags { |
349 | TSQ_THROTTLED, | |
350 | TSQ_QUEUED, | |
6f458dfb ED |
351 | TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */ |
352 | TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */ | |
353 | TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */ | |
563d34d0 ED |
354 | TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call |
355 | * tcp_v{4|6}_mtu_reduced() | |
356 | */ | |
46d3ceab ED |
357 | }; |
358 | ||
1da177e4 LT |
359 | static inline struct tcp_sock *tcp_sk(const struct sock *sk) |
360 | { | |
361 | return (struct tcp_sock *)sk; | |
362 | } | |
363 | ||
8feaf0c0 ACM |
364 | struct tcp_timewait_sock { |
365 | struct inet_timewait_sock tw_sk; | |
d475f090 ED |
366 | #define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt |
367 | #define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt | |
3a137d20 | 368 | u32 tw_rcv_wnd; |
ceaa1fef | 369 | u32 tw_ts_offset; |
3a137d20 | 370 | u32 tw_ts_recent; |
4fb17a60 NC |
371 | |
372 | /* The time we sent the last out-of-window ACK: */ | |
373 | u32 tw_last_oow_ack_time; | |
374 | ||
8feaf0c0 | 375 | long tw_ts_recent_stamp; |
cfb6eeb4 | 376 | #ifdef CONFIG_TCP_MD5SIG |
2397849b | 377 | struct tcp_md5sig_key *tw_md5_key; |
cfb6eeb4 | 378 | #endif |
8feaf0c0 ACM |
379 | }; |
380 | ||
381 | static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) | |
382 | { | |
383 | return (struct tcp_timewait_sock *)sk; | |
384 | } | |
385 | ||
10467163 JC |
386 | static inline bool tcp_passive_fastopen(const struct sock *sk) |
387 | { | |
388 | return (sk->sk_state == TCP_SYN_RECV && | |
389 | tcp_sk(sk)->fastopen_rsk != NULL); | |
390 | } | |
391 | ||
0536fcc0 | 392 | static inline void fastopen_queue_tune(struct sock *sk, int backlog) |
10467163 | 393 | { |
0536fcc0 | 394 | struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; |
dbf650b6 | 395 | int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn); |
0536fcc0 | 396 | |
dbf650b6 | 397 | queue->fastopenq.max_qlen = min_t(unsigned int, backlog, somaxconn); |
10467163 JC |
398 | } |
399 | ||
cd8ae852 ED |
400 | static inline void tcp_saved_syn_free(struct tcp_sock *tp) |
401 | { | |
402 | kfree(tp->saved_syn); | |
403 | tp->saved_syn = NULL; | |
404 | } | |
405 | ||
1da177e4 | 406 | #endif /* _LINUX_TCP_H */ |