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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> |
c8a553ad | 22 | #include <linux/dmaengine.h> |
1da177e4 | 23 | #include <net/sock.h> |
463c84b9 | 24 | #include <net/inet_connection_sock.h> |
8feaf0c0 | 25 | #include <net/inet_timewait_sock.h> |
607ca46e | 26 | #include <uapi/linux/tcp.h> |
1da177e4 | 27 | |
aa8223c7 ACM |
28 | static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb) |
29 | { | |
9c70220b | 30 | return (struct tcphdr *)skb_transport_header(skb); |
aa8223c7 ACM |
31 | } |
32 | ||
ab6a5bb6 ACM |
33 | static inline unsigned int tcp_hdrlen(const struct sk_buff *skb) |
34 | { | |
aa8223c7 | 35 | return tcp_hdr(skb)->doff * 4; |
ab6a5bb6 ACM |
36 | } |
37 | ||
38 | static inline unsigned int tcp_optlen(const struct sk_buff *skb) | |
39 | { | |
aa8223c7 | 40 | return (tcp_hdr(skb)->doff - 5) * 4; |
ab6a5bb6 ACM |
41 | } |
42 | ||
2100c8d2 YC |
43 | /* TCP Fast Open */ |
44 | #define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */ | |
45 | #define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */ | |
10467163 | 46 | #define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */ |
2100c8d2 YC |
47 | |
48 | /* TCP Fast Open Cookie as stored in memory */ | |
49 | struct tcp_fastopen_cookie { | |
50 | s8 len; | |
51 | u8 val[TCP_FASTOPEN_COOKIE_MAX]; | |
52 | }; | |
53 | ||
1da177e4 | 54 | /* This defines a selective acknowledgement block. */ |
269bd27e AV |
55 | struct tcp_sack_block_wire { |
56 | __be32 start_seq; | |
57 | __be32 end_seq; | |
58 | }; | |
59 | ||
1da177e4 | 60 | struct tcp_sack_block { |
3a137d20 ACM |
61 | u32 start_seq; |
62 | u32 end_seq; | |
1da177e4 LT |
63 | }; |
64 | ||
ab56222a VS |
65 | /*These are used to set the sack_ok field in struct tcp_options_received */ |
66 | #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */ | |
67 | #define TCP_FACK_ENABLED (1 << 1) /*1 = FACK is enabled locally*/ | |
68 | #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ | |
69 | ||
1da177e4 LT |
70 | struct tcp_options_received { |
71 | /* PAWS/RTTM data */ | |
72 | long ts_recent_stamp;/* Time we stored ts_recent (for aging) */ | |
3a137d20 ACM |
73 | u32 ts_recent; /* Time stamp to echo next */ |
74 | u32 rcv_tsval; /* Time stamp value */ | |
75 | u32 rcv_tsecr; /* Time stamp echo reply */ | |
76 | u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ | |
1da177e4 LT |
77 | tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ |
78 | dsack : 1, /* D-SACK is scheduled */ | |
79 | wscale_ok : 1, /* Wscale seen on SYN packet */ | |
80 | sack_ok : 4, /* SACK seen on SYN packet */ | |
81 | snd_wscale : 4, /* Window scaling received from sender */ | |
82 | rcv_wscale : 4; /* Window scaling to send to receiver */ | |
435cf559 WAS |
83 | u8 cookie_plus:6, /* bytes in authenticator/cookie option */ |
84 | cookie_out_never:1, | |
85 | cookie_in_always:1; | |
3a137d20 | 86 | u8 num_sacks; /* Number of SACK blocks */ |
435cf559 | 87 | u16 user_mss; /* mss requested by user in ioctl */ |
3a137d20 | 88 | u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ |
1da177e4 LT |
89 | }; |
90 | ||
519855c5 WAS |
91 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) |
92 | { | |
435cf559 WAS |
93 | rx_opt->tstamp_ok = rx_opt->sack_ok = 0; |
94 | rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
95 | rx_opt->cookie_plus = 0; | |
519855c5 WAS |
96 | } |
97 | ||
4389dded | 98 | /* This is the max number of SACKS that we'll generate and process. It's safe |
435cf559 | 99 | * to increase this, although since: |
4389dded AL |
100 | * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) |
101 | * only four options will fit in a standard TCP header */ | |
102 | #define TCP_NUM_SACKS 4 | |
103 | ||
435cf559 WAS |
104 | struct tcp_cookie_values; |
105 | struct tcp_request_sock_ops; | |
106 | ||
2e6599cb | 107 | struct tcp_request_sock { |
cfb6eeb4 YH |
108 | struct inet_request_sock req; |
109 | #ifdef CONFIG_TCP_MD5SIG | |
110 | /* Only used by TCP MD5 Signature so far. */ | |
b2e4b3de | 111 | const struct tcp_request_sock_ops *af_specific; |
cfb6eeb4 | 112 | #endif |
10467163 | 113 | struct sock *listener; /* needed for TFO */ |
435cf559 WAS |
114 | u32 rcv_isn; |
115 | u32 snt_isn; | |
9ad7c049 | 116 | u32 snt_synack; /* synack sent time */ |
10467163 JC |
117 | u32 rcv_nxt; /* the ack # by SYNACK. For |
118 | * FastOpen it's the seq# | |
119 | * after data-in-SYN. | |
120 | */ | |
2e6599cb ACM |
121 | }; |
122 | ||
60236fdd | 123 | static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) |
2e6599cb ACM |
124 | { |
125 | return (struct tcp_request_sock *)req; | |
126 | } | |
127 | ||
1da177e4 | 128 | struct tcp_sock { |
463c84b9 ACM |
129 | /* inet_connection_sock has to be the first member of tcp_sock */ |
130 | struct inet_connection_sock inet_conn; | |
2ff52f28 | 131 | u16 tcp_header_len; /* Bytes of tcp header to send */ |
2a3a041c | 132 | u16 xmit_size_goal_segs; /* Goal for segmenting output packets */ |
1da177e4 LT |
133 | |
134 | /* | |
135 | * Header prediction flags | |
136 | * 0x5?10 << 16 + snd_wnd in net byte order | |
137 | */ | |
dddc93c0 | 138 | __be32 pred_flags; |
1da177e4 LT |
139 | |
140 | /* | |
141 | * RFC793 variables by their proper names. This means you can | |
142 | * read the code and the spec side by side (and laugh ...) | |
143 | * See RFC793 and RFC1122. The RFC writes these in capitals. | |
144 | */ | |
3a137d20 | 145 | u32 rcv_nxt; /* What we want to receive next */ |
54287cc1 ED |
146 | u32 copied_seq; /* Head of yet unread data */ |
147 | u32 rcv_wup; /* rcv_nxt on last window update sent */ | |
3a137d20 | 148 | u32 snd_nxt; /* Next sequence we send */ |
1da177e4 | 149 | |
3a137d20 ACM |
150 | u32 snd_una; /* First byte we want an ack for */ |
151 | u32 snd_sml; /* Last byte of the most recently transmitted small packet */ | |
152 | u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ | |
153 | u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ | |
1da177e4 | 154 | |
46d3ceab ED |
155 | struct list_head tsq_node; /* anchor in tsq_tasklet.head list */ |
156 | unsigned long tsq_flags; | |
157 | ||
1da177e4 LT |
158 | /* Data for direct copy to user */ |
159 | struct { | |
160 | struct sk_buff_head prequeue; | |
161 | struct task_struct *task; | |
162 | struct iovec *iov; | |
163 | int memory; | |
164 | int len; | |
97fc2f08 CL |
165 | #ifdef CONFIG_NET_DMA |
166 | /* members for async copy */ | |
167 | struct dma_chan *dma_chan; | |
168 | int wakeup; | |
169 | struct dma_pinned_list *pinned_list; | |
170 | dma_cookie_t dma_cookie; | |
171 | #endif | |
1da177e4 LT |
172 | } ucopy; |
173 | ||
3a137d20 ACM |
174 | u32 snd_wl1; /* Sequence for window update */ |
175 | u32 snd_wnd; /* The window we expect to receive */ | |
176 | u32 max_window; /* Maximal window ever seen from peer */ | |
177 | u32 mss_cache; /* Cached effective mss, not including SACKS */ | |
1da177e4 | 178 | |
3a137d20 ACM |
179 | u32 window_clamp; /* Maximal window to advertise */ |
180 | u32 rcv_ssthresh; /* Current window clamp */ | |
1da177e4 | 181 | |
3a137d20 | 182 | u32 frto_highmark; /* snd_nxt when RTO occurred */ |
b79eeeb9 | 183 | u16 advmss; /* Advertised MSS */ |
3a137d20 | 184 | u8 frto_counter; /* Number of new acks after RTO */ |
36e31b0a AP |
185 | u8 nonagle : 4,/* Disable Nagle algorithm? */ |
186 | thin_lto : 1,/* Use linear timeouts for thin streams */ | |
7e380175 | 187 | thin_dupack : 1,/* Fast retransmit on first dupack */ |
ee995283 PE |
188 | repair : 1, |
189 | unused : 1; | |
190 | u8 repair_queue; | |
750ea2ba | 191 | u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */ |
783237e8 | 192 | early_retrans_delayed:1, /* Delayed ER timer installed */ |
67da22d2 | 193 | syn_data:1, /* SYN includes data */ |
783237e8 | 194 | syn_fastopen:1; /* SYN includes Fast Open option */ |
1da177e4 LT |
195 | |
196 | /* RTT measurement */ | |
3a137d20 ACM |
197 | u32 srtt; /* smoothed round trip time << 3 */ |
198 | u32 mdev; /* medium deviation */ | |
199 | u32 mdev_max; /* maximal mdev for the last rtt period */ | |
200 | u32 rttvar; /* smoothed mdev_max */ | |
201 | u32 rtt_seq; /* sequence number to update rttvar */ | |
202 | ||
203 | u32 packets_out; /* Packets which are "in flight" */ | |
3a137d20 | 204 | u32 retrans_out; /* Retransmitted packets out */ |
b79eeeb9 IJ |
205 | |
206 | u16 urg_data; /* Saved octet of OOB data and control flags */ | |
b79eeeb9 | 207 | u8 ecn_flags; /* ECN status bits. */ |
33f5f57e IJ |
208 | u8 reordering; /* Packet reordering metric. */ |
209 | u32 snd_up; /* Urgent pointer */ | |
210 | ||
211 | u8 keepalive_probes; /* num of allowed keep alive probes */ | |
1da177e4 LT |
212 | /* |
213 | * Options received (usually on last packet, some only on SYN packets). | |
214 | */ | |
1da177e4 LT |
215 | struct tcp_options_received rx_opt; |
216 | ||
217 | /* | |
218 | * Slow start and congestion control (see also Nagle, and Karn & Partridge) | |
219 | */ | |
3a137d20 ACM |
220 | u32 snd_ssthresh; /* Slow start size threshold */ |
221 | u32 snd_cwnd; /* Sending congestion window */ | |
f78a1b38 | 222 | u32 snd_cwnd_cnt; /* Linear increase counter */ |
e0ef57cc | 223 | u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ |
3a137d20 ACM |
224 | u32 snd_cwnd_used; |
225 | u32 snd_cwnd_stamp; | |
a262f0cd ND |
226 | u32 prior_cwnd; /* Congestion window at start of Recovery. */ |
227 | u32 prr_delivered; /* Number of newly delivered packets to | |
228 | * receiver in Recovery. */ | |
229 | u32 prr_out; /* Total number of pkts sent during Recovery. */ | |
1da177e4 | 230 | |
3a137d20 | 231 | u32 rcv_wnd; /* Current receiver window */ |
3a137d20 ACM |
232 | u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ |
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; | |
238 | u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */ | |
1da177e4 | 239 | |
b79eeeb9 IJ |
240 | /* from STCP, retrans queue hinting */ |
241 | struct sk_buff* lost_skb_hint; | |
242 | struct sk_buff *scoreboard_skb_hint; | |
243 | struct sk_buff *retransmit_skb_hint; | |
b79eeeb9 IJ |
244 | |
245 | struct sk_buff_head out_of_order_queue; /* Out of order segments go here */ | |
246 | ||
c0a788c4 | 247 | /* SACKs data, these 2 need to be together (see tcp_options_write) */ |
1da177e4 LT |
248 | struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ |
249 | struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ | |
250 | ||
fd6dad61 | 251 | struct tcp_sack_block recv_sack_cache[4]; |
6a438bbe | 252 | |
ecb97192 NC |
253 | struct sk_buff *highest_sack; /* skb just after the highest |
254 | * skb with SACKed bit set | |
a47e5a98 IJ |
255 | * (validity guaranteed only if |
256 | * sacked_out > 0) | |
257 | */ | |
d738cd8f | 258 | |
6a438bbe | 259 | int lost_cnt_hint; |
006f582c | 260 | u32 retransmit_high; /* L-bits may be on up to this seqno */ |
6a438bbe | 261 | |
b08d6cb2 IJ |
262 | u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */ |
263 | ||
4b749440 | 264 | u32 prior_ssthresh; /* ssthresh saved at recovery start */ |
3a137d20 | 265 | u32 high_seq; /* snd_nxt at onset of congestion */ |
1da177e4 | 266 | |
3a137d20 | 267 | u32 retrans_stamp; /* Timestamp of the last retransmit, |
1da177e4 LT |
268 | * also used in SYN-SENT to remember stamp of |
269 | * the first SYN. */ | |
3a137d20 | 270 | u32 undo_marker; /* tracking retrans started here. */ |
1da177e4 | 271 | int undo_retrans; /* number of undoable retransmissions. */ |
b79eeeb9 IJ |
272 | u32 total_retrans; /* Total retransmits for entire connection */ |
273 | ||
3a137d20 | 274 | u32 urg_seq; /* Seq of received urgent pointer */ |
1da177e4 LT |
275 | unsigned int keepalive_time; /* time before keep alive takes place */ |
276 | unsigned int keepalive_intvl; /* time interval between keep alive probes */ | |
1da177e4 | 277 | |
a0f82f64 | 278 | int linger2; |
1da177e4 LT |
279 | |
280 | /* Receiver side RTT estimation */ | |
281 | struct { | |
3a137d20 ACM |
282 | u32 rtt; |
283 | u32 seq; | |
284 | u32 time; | |
1da177e4 LT |
285 | } rcv_rtt_est; |
286 | ||
287 | /* Receiver queue space */ | |
288 | struct { | |
289 | int space; | |
3a137d20 ACM |
290 | u32 seq; |
291 | u32 time; | |
1da177e4 | 292 | } rcvq_space; |
0e7b1368 JH |
293 | |
294 | /* TCP-specific MTU probe information. */ | |
295 | struct { | |
3a137d20 ACM |
296 | u32 probe_seq_start; |
297 | u32 probe_seq_end; | |
0e7b1368 | 298 | } mtu_probe; |
563d34d0 ED |
299 | u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG |
300 | * while socket was owned by user. | |
301 | */ | |
cfb6eeb4 YH |
302 | |
303 | #ifdef CONFIG_TCP_MD5SIG | |
304 | /* TCP AF-Specific parts; only used by MD5 Signature support so far */ | |
b2e4b3de | 305 | const struct tcp_sock_af_ops *af_specific; |
cfb6eeb4 | 306 | |
b2e4b3de | 307 | /* TCP MD5 Signature Option information */ |
a8afca03 | 308 | struct tcp_md5sig_info __rcu *md5sig_info; |
cfb6eeb4 | 309 | #endif |
435cf559 WAS |
310 | |
311 | /* When the cookie options are generated and exchanged, then this | |
312 | * object holds a reference to them (cookie_values->kref). Also | |
313 | * contains related tcp_cookie_transactions fields. | |
314 | */ | |
315 | struct tcp_cookie_values *cookie_values; | |
10467163 JC |
316 | |
317 | /* TCP fastopen related information */ | |
318 | struct tcp_fastopen_request *fastopen_req; | |
319 | /* fastopen_rsk points to request_sock that resulted in this big | |
320 | * socket. Used to retransmit SYNACKs etc. | |
321 | */ | |
322 | struct request_sock *fastopen_rsk; | |
1da177e4 LT |
323 | }; |
324 | ||
46d3ceab ED |
325 | enum tsq_flags { |
326 | TSQ_THROTTLED, | |
327 | TSQ_QUEUED, | |
6f458dfb ED |
328 | TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */ |
329 | TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */ | |
330 | TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */ | |
563d34d0 ED |
331 | TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call |
332 | * tcp_v{4|6}_mtu_reduced() | |
333 | */ | |
46d3ceab ED |
334 | }; |
335 | ||
1da177e4 LT |
336 | static inline struct tcp_sock *tcp_sk(const struct sock *sk) |
337 | { | |
338 | return (struct tcp_sock *)sk; | |
339 | } | |
340 | ||
8feaf0c0 ACM |
341 | struct tcp_timewait_sock { |
342 | struct inet_timewait_sock tw_sk; | |
3a137d20 ACM |
343 | u32 tw_rcv_nxt; |
344 | u32 tw_snd_nxt; | |
345 | u32 tw_rcv_wnd; | |
346 | u32 tw_ts_recent; | |
8feaf0c0 | 347 | long tw_ts_recent_stamp; |
cfb6eeb4 | 348 | #ifdef CONFIG_TCP_MD5SIG |
2397849b | 349 | struct tcp_md5sig_key *tw_md5_key; |
cfb6eeb4 | 350 | #endif |
435cf559 WAS |
351 | /* Few sockets in timewait have cookies; in that case, then this |
352 | * object holds a reference to them (tw_cookie_values->kref). | |
353 | */ | |
354 | struct tcp_cookie_values *tw_cookie_values; | |
8feaf0c0 ACM |
355 | }; |
356 | ||
357 | static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) | |
358 | { | |
359 | return (struct tcp_timewait_sock *)sk; | |
360 | } | |
361 | ||
10467163 JC |
362 | static inline bool tcp_passive_fastopen(const struct sock *sk) |
363 | { | |
364 | return (sk->sk_state == TCP_SYN_RECV && | |
365 | tcp_sk(sk)->fastopen_rsk != NULL); | |
366 | } | |
367 | ||
368 | static inline bool fastopen_cookie_present(struct tcp_fastopen_cookie *foc) | |
369 | { | |
370 | return foc->len != -1; | |
371 | } | |
372 | ||
bb68b647 CP |
373 | extern void tcp_sock_destruct(struct sock *sk); |
374 | ||
10467163 JC |
375 | static inline int fastopen_init_queue(struct sock *sk, int backlog) |
376 | { | |
377 | struct request_sock_queue *queue = | |
378 | &inet_csk(sk)->icsk_accept_queue; | |
379 | ||
380 | if (queue->fastopenq == NULL) { | |
381 | queue->fastopenq = kzalloc( | |
382 | sizeof(struct fastopen_queue), | |
383 | sk->sk_allocation); | |
384 | if (queue->fastopenq == NULL) | |
385 | return -ENOMEM; | |
bb68b647 CP |
386 | |
387 | sk->sk_destruct = tcp_sock_destruct; | |
10467163 JC |
388 | spin_lock_init(&queue->fastopenq->lock); |
389 | } | |
390 | queue->fastopenq->max_qlen = backlog; | |
391 | return 0; | |
392 | } | |
393 | ||
1da177e4 | 394 | #endif /* _LINUX_TCP_H */ |