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]; | |
61 | }; | |
62 | ||
1da177e4 | 63 | /* This defines a selective acknowledgement block. */ |
269bd27e AV |
64 | struct tcp_sack_block_wire { |
65 | __be32 start_seq; | |
66 | __be32 end_seq; | |
67 | }; | |
68 | ||
1da177e4 | 69 | struct tcp_sack_block { |
3a137d20 ACM |
70 | u32 start_seq; |
71 | u32 end_seq; | |
1da177e4 LT |
72 | }; |
73 | ||
ab56222a VS |
74 | /*These are used to set the sack_ok field in struct tcp_options_received */ |
75 | #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */ | |
76 | #define TCP_FACK_ENABLED (1 << 1) /*1 = FACK is enabled locally*/ | |
77 | #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ | |
78 | ||
1da177e4 LT |
79 | struct tcp_options_received { |
80 | /* PAWS/RTTM data */ | |
81 | long ts_recent_stamp;/* Time we stored ts_recent (for aging) */ | |
3a137d20 ACM |
82 | u32 ts_recent; /* Time stamp to echo next */ |
83 | u32 rcv_tsval; /* Time stamp value */ | |
84 | u32 rcv_tsecr; /* Time stamp echo reply */ | |
85 | u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ | |
1da177e4 LT |
86 | tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ |
87 | dsack : 1, /* D-SACK is scheduled */ | |
88 | wscale_ok : 1, /* Wscale seen on SYN packet */ | |
89 | sack_ok : 4, /* SACK seen on SYN packet */ | |
90 | snd_wscale : 4, /* Window scaling received from sender */ | |
91 | rcv_wscale : 4; /* Window scaling to send to receiver */ | |
3a137d20 | 92 | u8 num_sacks; /* Number of SACK blocks */ |
435cf559 | 93 | u16 user_mss; /* mss requested by user in ioctl */ |
3a137d20 | 94 | u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ |
1da177e4 LT |
95 | }; |
96 | ||
519855c5 WAS |
97 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) |
98 | { | |
435cf559 WAS |
99 | rx_opt->tstamp_ok = rx_opt->sack_ok = 0; |
100 | rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
519855c5 WAS |
101 | } |
102 | ||
4389dded | 103 | /* This is the max number of SACKS that we'll generate and process. It's safe |
435cf559 | 104 | * to increase this, although since: |
4389dded AL |
105 | * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) |
106 | * only four options will fit in a standard TCP header */ | |
107 | #define TCP_NUM_SACKS 4 | |
108 | ||
435cf559 WAS |
109 | struct tcp_request_sock_ops; |
110 | ||
2e6599cb | 111 | struct tcp_request_sock { |
cfb6eeb4 | 112 | struct inet_request_sock req; |
b2e4b3de | 113 | const struct tcp_request_sock_ops *af_specific; |
10467163 | 114 | struct sock *listener; /* needed for TFO */ |
435cf559 WAS |
115 | u32 rcv_isn; |
116 | u32 snt_isn; | |
9ad7c049 | 117 | u32 snt_synack; /* synack sent time */ |
10467163 JC |
118 | u32 rcv_nxt; /* the ack # by SYNACK. For |
119 | * FastOpen it's the seq# | |
120 | * after data-in-SYN. | |
121 | */ | |
2e6599cb ACM |
122 | }; |
123 | ||
60236fdd | 124 | static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) |
2e6599cb ACM |
125 | { |
126 | return (struct tcp_request_sock *)req; | |
127 | } | |
128 | ||
1da177e4 | 129 | struct tcp_sock { |
463c84b9 ACM |
130 | /* inet_connection_sock has to be the first member of tcp_sock */ |
131 | struct inet_connection_sock inet_conn; | |
2ff52f28 | 132 | u16 tcp_header_len; /* Bytes of tcp header to send */ |
605ad7f1 | 133 | u16 gso_segs; /* Max number of segs per GSO packet */ |
1da177e4 LT |
134 | |
135 | /* | |
136 | * Header prediction flags | |
137 | * 0x5?10 << 16 + snd_wnd in net byte order | |
138 | */ | |
dddc93c0 | 139 | __be32 pred_flags; |
1da177e4 LT |
140 | |
141 | /* | |
142 | * RFC793 variables by their proper names. This means you can | |
143 | * read the code and the spec side by side (and laugh ...) | |
144 | * See RFC793 and RFC1122. The RFC writes these in capitals. | |
145 | */ | |
3a137d20 | 146 | u32 rcv_nxt; /* What we want to receive next */ |
54287cc1 ED |
147 | u32 copied_seq; /* Head of yet unread data */ |
148 | u32 rcv_wup; /* rcv_nxt on last window update sent */ | |
3a137d20 | 149 | u32 snd_nxt; /* Next sequence we send */ |
1da177e4 | 150 | |
3a137d20 ACM |
151 | u32 snd_una; /* First byte we want an ack for */ |
152 | u32 snd_sml; /* Last byte of the most recently transmitted small packet */ | |
153 | u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ | |
154 | u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ | |
1da177e4 | 155 | |
ceaa1fef AV |
156 | u32 tsoffset; /* timestamp offset */ |
157 | ||
46d3ceab ED |
158 | struct list_head tsq_node; /* anchor in tsq_tasklet.head list */ |
159 | unsigned long tsq_flags; | |
160 | ||
1da177e4 LT |
161 | /* Data for direct copy to user */ |
162 | struct { | |
163 | struct sk_buff_head prequeue; | |
164 | struct task_struct *task; | |
f4362a2c | 165 | struct msghdr *msg; |
1da177e4 LT |
166 | int memory; |
167 | int len; | |
168 | } ucopy; | |
169 | ||
3a137d20 ACM |
170 | u32 snd_wl1; /* Sequence for window update */ |
171 | u32 snd_wnd; /* The window we expect to receive */ | |
172 | u32 max_window; /* Maximal window ever seen from peer */ | |
173 | u32 mss_cache; /* Cached effective mss, not including SACKS */ | |
1da177e4 | 174 | |
3a137d20 ACM |
175 | u32 window_clamp; /* Maximal window to advertise */ |
176 | u32 rcv_ssthresh; /* Current window clamp */ | |
1da177e4 | 177 | |
b79eeeb9 | 178 | u16 advmss; /* Advertised MSS */ |
9b44190d | 179 | u8 unused; |
36e31b0a AP |
180 | u8 nonagle : 4,/* Disable Nagle algorithm? */ |
181 | thin_lto : 1,/* Use linear timeouts for thin streams */ | |
7e380175 | 182 | thin_dupack : 1,/* Fast retransmit on first dupack */ |
e33099f9 YC |
183 | repair : 1, |
184 | frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */ | |
ee995283 | 185 | u8 repair_queue; |
750ea2ba | 186 | u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */ |
67da22d2 | 187 | syn_data:1, /* SYN includes data */ |
6f73601e | 188 | syn_fastopen:1, /* SYN includes Fast Open option */ |
ca8a2263 NC |
189 | syn_data_acked:1,/* data in SYN is acked by SYN-ACK */ |
190 | is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */ | |
9b717a8d | 191 | u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */ |
1da177e4 LT |
192 | |
193 | /* RTT measurement */ | |
740b0f18 ED |
194 | u32 srtt_us; /* smoothed round trip time << 3 in usecs */ |
195 | u32 mdev_us; /* medium deviation */ | |
196 | u32 mdev_max_us; /* maximal mdev for the last rtt period */ | |
197 | u32 rttvar_us; /* smoothed mdev_max */ | |
3a137d20 ACM |
198 | u32 rtt_seq; /* sequence number to update rttvar */ |
199 | ||
200 | u32 packets_out; /* Packets which are "in flight" */ | |
3a137d20 | 201 | u32 retrans_out; /* Retransmitted packets out */ |
ca8a2263 NC |
202 | u32 max_packets_out; /* max packets_out in last window */ |
203 | u32 max_packets_seq; /* right edge of max_packets_out flight */ | |
b79eeeb9 IJ |
204 | |
205 | u16 urg_data; /* Saved octet of OOB data and control flags */ | |
b79eeeb9 | 206 | u8 ecn_flags; /* ECN status bits. */ |
dca145ff ED |
207 | u8 keepalive_probes; /* num of allowed keep alive probes */ |
208 | u32 reordering; /* Packet reordering metric. */ | |
33f5f57e IJ |
209 | u32 snd_up; /* Urgent pointer */ |
210 | ||
1da177e4 LT |
211 | /* |
212 | * Options received (usually on last packet, some only on SYN packets). | |
213 | */ | |
1da177e4 LT |
214 | struct tcp_options_received rx_opt; |
215 | ||
216 | /* | |
217 | * Slow start and congestion control (see also Nagle, and Karn & Partridge) | |
218 | */ | |
3a137d20 ACM |
219 | u32 snd_ssthresh; /* Slow start size threshold */ |
220 | u32 snd_cwnd; /* Sending congestion window */ | |
f78a1b38 | 221 | u32 snd_cwnd_cnt; /* Linear increase counter */ |
e0ef57cc | 222 | u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ |
3a137d20 ACM |
223 | u32 snd_cwnd_used; |
224 | u32 snd_cwnd_stamp; | |
a262f0cd ND |
225 | u32 prior_cwnd; /* Congestion window at start of Recovery. */ |
226 | u32 prr_delivered; /* Number of newly delivered packets to | |
227 | * receiver in Recovery. */ | |
228 | u32 prr_out; /* Total number of pkts sent during Recovery. */ | |
1da177e4 | 229 | |
3a137d20 | 230 | u32 rcv_wnd; /* Current receiver window */ |
3a137d20 | 231 | u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ |
c9bee3b7 | 232 | u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */ |
3a137d20 | 233 | u32 pushed_seq; /* Last pushed seq, required to talk to windows */ |
b79eeeb9 IJ |
234 | u32 lost_out; /* Lost packets */ |
235 | u32 sacked_out; /* SACK'd packets */ | |
236 | u32 fackets_out; /* FACK'd packets */ | |
237 | u32 tso_deferred; | |
1da177e4 | 238 | |
b79eeeb9 IJ |
239 | /* from STCP, retrans queue hinting */ |
240 | struct sk_buff* lost_skb_hint; | |
b79eeeb9 | 241 | struct sk_buff *retransmit_skb_hint; |
b79eeeb9 | 242 | |
996b175e ED |
243 | /* OOO segments go in this list. Note that socket lock must be held, |
244 | * as we do not use sk_buff_head lock. | |
245 | */ | |
246 | struct sk_buff_head out_of_order_queue; | |
b79eeeb9 | 247 | |
c0a788c4 | 248 | /* SACKs data, these 2 need to be together (see tcp_options_write) */ |
1da177e4 LT |
249 | struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ |
250 | struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ | |
251 | ||
fd6dad61 | 252 | struct tcp_sack_block recv_sack_cache[4]; |
6a438bbe | 253 | |
ecb97192 NC |
254 | struct sk_buff *highest_sack; /* skb just after the highest |
255 | * skb with SACKed bit set | |
a47e5a98 IJ |
256 | * (validity guaranteed only if |
257 | * sacked_out > 0) | |
258 | */ | |
d738cd8f | 259 | |
6a438bbe | 260 | int lost_cnt_hint; |
006f582c | 261 | u32 retransmit_high; /* L-bits may be on up to this seqno */ |
6a438bbe | 262 | |
b08d6cb2 IJ |
263 | u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */ |
264 | ||
4b749440 | 265 | u32 prior_ssthresh; /* ssthresh saved at recovery start */ |
3a137d20 | 266 | u32 high_seq; /* snd_nxt at onset of congestion */ |
1da177e4 | 267 | |
3a137d20 | 268 | u32 retrans_stamp; /* Timestamp of the last retransmit, |
1da177e4 LT |
269 | * also used in SYN-SENT to remember stamp of |
270 | * the first SYN. */ | |
989e04c5 | 271 | u32 undo_marker; /* snd_una upon a new recovery episode. */ |
1da177e4 | 272 | int undo_retrans; /* number of undoable retransmissions. */ |
b79eeeb9 IJ |
273 | u32 total_retrans; /* Total retransmits for entire connection */ |
274 | ||
3a137d20 | 275 | u32 urg_seq; /* Seq of received urgent pointer */ |
1da177e4 LT |
276 | unsigned int keepalive_time; /* time before keep alive takes place */ |
277 | unsigned int keepalive_intvl; /* time interval between keep alive probes */ | |
1da177e4 | 278 | |
a0f82f64 | 279 | int linger2; |
1da177e4 LT |
280 | |
281 | /* Receiver side RTT estimation */ | |
282 | struct { | |
3a137d20 ACM |
283 | u32 rtt; |
284 | u32 seq; | |
285 | u32 time; | |
1da177e4 LT |
286 | } rcv_rtt_est; |
287 | ||
288 | /* Receiver queue space */ | |
289 | struct { | |
290 | int space; | |
3a137d20 ACM |
291 | u32 seq; |
292 | u32 time; | |
1da177e4 | 293 | } rcvq_space; |
0e7b1368 JH |
294 | |
295 | /* TCP-specific MTU probe information. */ | |
296 | struct { | |
3a137d20 ACM |
297 | u32 probe_seq_start; |
298 | u32 probe_seq_end; | |
0e7b1368 | 299 | } mtu_probe; |
563d34d0 ED |
300 | u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG |
301 | * while socket was owned by user. | |
302 | */ | |
cfb6eeb4 YH |
303 | |
304 | #ifdef CONFIG_TCP_MD5SIG | |
305 | /* TCP AF-Specific parts; only used by MD5 Signature support so far */ | |
b2e4b3de | 306 | const struct tcp_sock_af_ops *af_specific; |
cfb6eeb4 | 307 | |
b2e4b3de | 308 | /* TCP MD5 Signature Option information */ |
a8afca03 | 309 | struct tcp_md5sig_info __rcu *md5sig_info; |
cfb6eeb4 | 310 | #endif |
435cf559 | 311 | |
10467163 JC |
312 | /* TCP fastopen related information */ |
313 | struct tcp_fastopen_request *fastopen_req; | |
314 | /* fastopen_rsk points to request_sock that resulted in this big | |
315 | * socket. Used to retransmit SYNACKs etc. | |
316 | */ | |
317 | struct request_sock *fastopen_rsk; | |
1da177e4 LT |
318 | }; |
319 | ||
46d3ceab ED |
320 | enum tsq_flags { |
321 | TSQ_THROTTLED, | |
322 | TSQ_QUEUED, | |
6f458dfb ED |
323 | TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */ |
324 | TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */ | |
325 | TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */ | |
563d34d0 ED |
326 | TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call |
327 | * tcp_v{4|6}_mtu_reduced() | |
328 | */ | |
46d3ceab ED |
329 | }; |
330 | ||
1da177e4 LT |
331 | static inline struct tcp_sock *tcp_sk(const struct sock *sk) |
332 | { | |
333 | return (struct tcp_sock *)sk; | |
334 | } | |
335 | ||
8feaf0c0 ACM |
336 | struct tcp_timewait_sock { |
337 | struct inet_timewait_sock tw_sk; | |
3a137d20 ACM |
338 | u32 tw_rcv_nxt; |
339 | u32 tw_snd_nxt; | |
340 | u32 tw_rcv_wnd; | |
ceaa1fef | 341 | u32 tw_ts_offset; |
3a137d20 | 342 | u32 tw_ts_recent; |
8feaf0c0 | 343 | long tw_ts_recent_stamp; |
cfb6eeb4 | 344 | #ifdef CONFIG_TCP_MD5SIG |
2397849b | 345 | struct tcp_md5sig_key *tw_md5_key; |
cfb6eeb4 | 346 | #endif |
8feaf0c0 ACM |
347 | }; |
348 | ||
349 | static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) | |
350 | { | |
351 | return (struct tcp_timewait_sock *)sk; | |
352 | } | |
353 | ||
10467163 JC |
354 | static inline bool tcp_passive_fastopen(const struct sock *sk) |
355 | { | |
356 | return (sk->sk_state == TCP_SYN_RECV && | |
357 | tcp_sk(sk)->fastopen_rsk != NULL); | |
358 | } | |
359 | ||
bb68b647 CP |
360 | extern void tcp_sock_destruct(struct sock *sk); |
361 | ||
10467163 JC |
362 | static inline int fastopen_init_queue(struct sock *sk, int backlog) |
363 | { | |
364 | struct request_sock_queue *queue = | |
365 | &inet_csk(sk)->icsk_accept_queue; | |
366 | ||
367 | if (queue->fastopenq == NULL) { | |
368 | queue->fastopenq = kzalloc( | |
369 | sizeof(struct fastopen_queue), | |
370 | sk->sk_allocation); | |
371 | if (queue->fastopenq == NULL) | |
372 | return -ENOMEM; | |
bb68b647 CP |
373 | |
374 | sk->sk_destruct = tcp_sock_destruct; | |
10467163 JC |
375 | spin_lock_init(&queue->fastopenq->lock); |
376 | } | |
377 | queue->fastopenq->max_qlen = backlog; | |
378 | return 0; | |
379 | } | |
380 | ||
1da177e4 | 381 | #endif /* _LINUX_TCP_H */ |