Line data Source code
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 :
20 : #include <linux/types.h>
21 : #include <asm/byteorder.h>
22 : #include <linux/socket.h>
23 :
24 : struct tcphdr {
25 : __be16 source;
26 : __be16 dest;
27 : __be32 seq;
28 : __be32 ack_seq;
29 : #if defined(__LITTLE_ENDIAN_BITFIELD)
30 : __u16 res1:4,
31 : doff:4,
32 : fin:1,
33 : syn:1,
34 : rst:1,
35 : psh:1,
36 : ack:1,
37 : urg:1,
38 : ece:1,
39 : cwr:1;
40 : #elif defined(__BIG_ENDIAN_BITFIELD)
41 : __u16 doff:4,
42 : res1:4,
43 : cwr:1,
44 : ece:1,
45 : urg:1,
46 : ack:1,
47 : psh:1,
48 : rst:1,
49 : syn:1,
50 : fin:1;
51 : #else
52 : #error "Adjust your <asm/byteorder.h> defines"
53 : #endif
54 : __be16 window;
55 : __sum16 check;
56 : __be16 urg_ptr;
57 : };
58 :
59 : /*
60 : * The union cast uses a gcc extension to avoid aliasing problems
61 : * (union is compatible to any of its members)
62 : * This means this part of the code is -fstrict-aliasing safe now.
63 : */
64 : union tcp_word_hdr {
65 : struct tcphdr hdr;
66 : __be32 words[5];
67 : };
68 :
69 : #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
70 :
71 : enum {
72 : TCP_FLAG_CWR = __cpu_to_be32(0x00800000),
73 : TCP_FLAG_ECE = __cpu_to_be32(0x00400000),
74 : TCP_FLAG_URG = __cpu_to_be32(0x00200000),
75 : TCP_FLAG_ACK = __cpu_to_be32(0x00100000),
76 : TCP_FLAG_PSH = __cpu_to_be32(0x00080000),
77 : TCP_FLAG_RST = __cpu_to_be32(0x00040000),
78 : TCP_FLAG_SYN = __cpu_to_be32(0x00020000),
79 : TCP_FLAG_FIN = __cpu_to_be32(0x00010000),
80 : TCP_RESERVED_BITS = __cpu_to_be32(0x0F000000),
81 : TCP_DATA_OFFSET = __cpu_to_be32(0xF0000000)
82 : };
83 :
84 : /*
85 : * TCP general constants
86 : */
87 : #define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */
88 : #define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */
89 :
90 : /* TCP socket options */
91 : #define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
92 : #define TCP_MAXSEG 2 /* Limit MSS */
93 : #define TCP_CORK 3 /* Never send partially complete segments */
94 : #define TCP_KEEPIDLE 4 /* Start keeplives after this period */
95 : #define TCP_KEEPINTVL 5 /* Interval between keepalives */
96 : #define TCP_KEEPCNT 6 /* Number of keepalives before death */
97 : #define TCP_SYNCNT 7 /* Number of SYN retransmits */
98 : #define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
99 : #define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
100 : #define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
101 : #define TCP_INFO 11 /* Information about this connection. */
102 : #define TCP_QUICKACK 12 /* Block/reenable quick acks */
103 : #define TCP_CONGESTION 13 /* Congestion control algorithm */
104 : #define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */
105 : #define TCP_COOKIE_TRANSACTIONS 15 /* TCP Cookie Transactions */
106 :
107 : /* for TCP_INFO socket option */
108 : #define TCPI_OPT_TIMESTAMPS 1
109 : #define TCPI_OPT_SACK 2
110 : #define TCPI_OPT_WSCALE 4
111 : #define TCPI_OPT_ECN 8
112 :
113 : enum tcp_ca_state {
114 : TCP_CA_Open = 0,
115 : #define TCPF_CA_Open (1<<TCP_CA_Open)
116 : TCP_CA_Disorder = 1,
117 : #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
118 : TCP_CA_CWR = 2,
119 : #define TCPF_CA_CWR (1<<TCP_CA_CWR)
120 : TCP_CA_Recovery = 3,
121 : #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
122 : TCP_CA_Loss = 4
123 : #define TCPF_CA_Loss (1<<TCP_CA_Loss)
124 : };
125 :
126 : struct tcp_info {
127 : __u8 tcpi_state;
128 : __u8 tcpi_ca_state;
129 : __u8 tcpi_retransmits;
130 : __u8 tcpi_probes;
131 : __u8 tcpi_backoff;
132 : __u8 tcpi_options;
133 : __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
134 :
135 : __u32 tcpi_rto;
136 : __u32 tcpi_ato;
137 : __u32 tcpi_snd_mss;
138 : __u32 tcpi_rcv_mss;
139 :
140 : __u32 tcpi_unacked;
141 : __u32 tcpi_sacked;
142 : __u32 tcpi_lost;
143 : __u32 tcpi_retrans;
144 : __u32 tcpi_fackets;
145 :
146 : /* Times. */
147 : __u32 tcpi_last_data_sent;
148 : __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
149 : __u32 tcpi_last_data_recv;
150 : __u32 tcpi_last_ack_recv;
151 :
152 : /* Metrics. */
153 : __u32 tcpi_pmtu;
154 : __u32 tcpi_rcv_ssthresh;
155 : __u32 tcpi_rtt;
156 : __u32 tcpi_rttvar;
157 : __u32 tcpi_snd_ssthresh;
158 : __u32 tcpi_snd_cwnd;
159 : __u32 tcpi_advmss;
160 : __u32 tcpi_reordering;
161 :
162 : __u32 tcpi_rcv_rtt;
163 : __u32 tcpi_rcv_space;
164 :
165 : __u32 tcpi_total_retrans;
166 : };
167 :
168 : /* for TCP_MD5SIG socket option */
169 : #define TCP_MD5SIG_MAXKEYLEN 80
170 :
171 : struct tcp_md5sig {
172 : struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
173 : __u16 __tcpm_pad1; /* zero */
174 : __u16 tcpm_keylen; /* key length */
175 : __u32 __tcpm_pad2; /* zero */
176 : __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
177 : };
178 :
179 : /* for TCP_COOKIE_TRANSACTIONS (TCPCT) socket option */
180 : #define TCP_COOKIE_MIN 8 /* 64-bits */
181 : #define TCP_COOKIE_MAX 16 /* 128-bits */
182 : #define TCP_COOKIE_PAIR_SIZE (2*TCP_COOKIE_MAX)
183 :
184 : /* Flags for both getsockopt and setsockopt */
185 : #define TCP_COOKIE_IN_ALWAYS (1 << 0) /* Discard SYN without cookie */
186 : #define TCP_COOKIE_OUT_NEVER (1 << 1) /* Prohibit outgoing cookies,
187 : * supercedes everything. */
188 :
189 : /* Flags for getsockopt */
190 : #define TCP_S_DATA_IN (1 << 2) /* Was data received? */
191 : #define TCP_S_DATA_OUT (1 << 3) /* Was data sent? */
192 :
193 : /* TCP_COOKIE_TRANSACTIONS data */
194 : struct tcp_cookie_transactions {
195 : __u16 tcpct_flags; /* see above */
196 : __u8 __tcpct_pad1; /* zero */
197 : __u8 tcpct_cookie_desired; /* bytes */
198 : __u16 tcpct_s_data_desired; /* bytes of variable data */
199 : __u16 tcpct_used; /* bytes in value */
200 : __u8 tcpct_value[TCP_MSS_DEFAULT];
201 : };
202 :
203 : #ifdef __KERNEL__
204 :
205 : #include <linux/skbuff.h>
206 : #include <linux/dmaengine.h>
207 : #include <net/sock.h>
208 : #include <net/inet_connection_sock.h>
209 : #include <net/inet_timewait_sock.h>
210 :
211 : static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
212 : {
213 : return (struct tcphdr *)skb_transport_header(skb);
214 : }
215 :
216 : static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
217 : {
218 : return tcp_hdr(skb)->doff * 4;
219 : }
220 :
221 : static inline unsigned int tcp_optlen(const struct sk_buff *skb)
222 : {
223 : return (tcp_hdr(skb)->doff - 5) * 4;
224 : }
225 :
226 : /* This defines a selective acknowledgement block. */
227 : struct tcp_sack_block_wire {
228 : __be32 start_seq;
229 : __be32 end_seq;
230 : };
231 1 :
232 : struct tcp_sack_block {
233 : u32 start_seq;
234 : u32 end_seq;
235 : };
236 1 :
237 : struct tcp_options_received {
238 : /* PAWS/RTTM data */
239 : long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
240 : u32 ts_recent; /* Time stamp to echo next */
241 : u32 rcv_tsval; /* Time stamp value */
242 : u32 rcv_tsecr; /* Time stamp echo reply */
243 : u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
244 : tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
245 : dsack : 1, /* D-SACK is scheduled */
246 : wscale_ok : 1, /* Wscale seen on SYN packet */
247 : sack_ok : 4, /* SACK seen on SYN packet */
248 : snd_wscale : 4, /* Window scaling received from sender */
249 : rcv_wscale : 4; /* Window scaling to send to receiver */
250 : u8 cookie_plus:6, /* bytes in authenticator/cookie option */
251 : cookie_out_never:1,
252 : cookie_in_always:1;
253 : u8 num_sacks; /* Number of SACK blocks */
254 : u16 user_mss; /* mss requested by user in ioctl */
255 : u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
256 : };
257 :
258 : static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
259 : {
260 : rx_opt->tstamp_ok = rx_opt->sack_ok = 0;
261 : rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
262 : rx_opt->cookie_plus = 0;
263 : }
264 1 :
265 : /* This is the max number of SACKS that we'll generate and process. It's safe
266 : * to increase this, although since:
267 : * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
268 : * only four options will fit in a standard TCP header */
269 : #define TCP_NUM_SACKS 4
270 :
271 : struct tcp_cookie_values;
272 : struct tcp_request_sock_ops;
273 :
274 : struct tcp_request_sock {
275 : struct inet_request_sock req;
276 : #ifdef CONFIG_TCP_MD5SIG
277 : /* Only used by TCP MD5 Signature so far. */
278 : const struct tcp_request_sock_ops *af_specific;
279 : #endif
280 : u32 rcv_isn;
281 : u32 snt_isn;
282 : };
283 :
284 : static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
285 : {
286 : return (struct tcp_request_sock *)req;
287 : }
288 5 :
289 : struct tcp_sock {
290 : /* inet_connection_sock has to be the first member of tcp_sock */
291 : struct inet_connection_sock inet_conn;
292 : u16 tcp_header_len; /* Bytes of tcp header to send */
293 : u16 xmit_size_goal_segs; /* Goal for segmenting output packets */
294 :
295 : /*
296 : * Header prediction flags
297 : * 0x5?10 << 16 + snd_wnd in net byte order
298 : */
299 : __be32 pred_flags;
300 :
301 : /*
302 : * RFC793 variables by their proper names. This means you can
303 : * read the code and the spec side by side (and laugh ...)
304 : * See RFC793 and RFC1122. The RFC writes these in capitals.
305 : */
306 : u32 rcv_nxt; /* What we want to receive next */
307 : u32 copied_seq; /* Head of yet unread data */
308 : u32 rcv_wup; /* rcv_nxt on last window update sent */
309 : u32 snd_nxt; /* Next sequence we send */
310 :
311 : u32 snd_una; /* First byte we want an ack for */
312 : u32 snd_sml; /* Last byte of the most recently transmitted small packet */
313 : u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
314 : u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
315 :
316 : /* Data for direct copy to user */
317 : struct {
318 : struct sk_buff_head prequeue;
319 : struct task_struct *task;
320 : struct iovec *iov;
321 : int memory;
322 : int len;
323 : #ifdef CONFIG_NET_DMA
324 : /* members for async copy */
325 : struct dma_chan *dma_chan;
326 : int wakeup;
327 : struct dma_pinned_list *pinned_list;
328 : dma_cookie_t dma_cookie;
329 : #endif
330 : } ucopy;
331 :
332 : u32 snd_wl1; /* Sequence for window update */
333 : u32 snd_wnd; /* The window we expect to receive */
334 : u32 max_window; /* Maximal window ever seen from peer */
335 : u32 mss_cache; /* Cached effective mss, not including SACKS */
336 :
337 : u32 window_clamp; /* Maximal window to advertise */
338 : u32 rcv_ssthresh; /* Current window clamp */
339 :
340 : u32 frto_highmark; /* snd_nxt when RTO occurred */
341 : u16 advmss; /* Advertised MSS */
342 : u8 frto_counter; /* Number of new acks after RTO */
343 : u8 nonagle; /* Disable Nagle algorithm? */
344 :
345 : /* RTT measurement */
346 : u32 srtt; /* smoothed round trip time << 3 */
347 : u32 mdev; /* medium deviation */
348 : u32 mdev_max; /* maximal mdev for the last rtt period */
349 : u32 rttvar; /* smoothed mdev_max */
350 : u32 rtt_seq; /* sequence number to update rttvar */
351 :
352 : u32 packets_out; /* Packets which are "in flight" */
353 : u32 retrans_out; /* Retransmitted packets out */
354 :
355 : u16 urg_data; /* Saved octet of OOB data and control flags */
356 : u8 ecn_flags; /* ECN status bits. */
357 : u8 reordering; /* Packet reordering metric. */
358 : u32 snd_up; /* Urgent pointer */
359 :
360 : u8 keepalive_probes; /* num of allowed keep alive probes */
361 : /*
362 : * Options received (usually on last packet, some only on SYN packets).
363 : */
364 : struct tcp_options_received rx_opt;
365 :
366 : /*
367 : * Slow start and congestion control (see also Nagle, and Karn & Partridge)
368 : */
369 : u32 snd_ssthresh; /* Slow start size threshold */
370 : u32 snd_cwnd; /* Sending congestion window */
371 : u32 snd_cwnd_cnt; /* Linear increase counter */
372 : u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
373 : u32 snd_cwnd_used;
374 : u32 snd_cwnd_stamp;
375 :
376 : u32 rcv_wnd; /* Current receiver window */
377 : u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
378 : u32 pushed_seq; /* Last pushed seq, required to talk to windows */
379 : u32 lost_out; /* Lost packets */
380 : u32 sacked_out; /* SACK'd packets */
381 : u32 fackets_out; /* FACK'd packets */
382 : u32 tso_deferred;
383 : u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */
384 :
385 : /* from STCP, retrans queue hinting */
386 : struct sk_buff* lost_skb_hint;
387 : struct sk_buff *scoreboard_skb_hint;
388 : struct sk_buff *retransmit_skb_hint;
389 :
390 : struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
391 :
392 : /* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */
393 : struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
394 : struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
395 :
396 : struct tcp_sack_block recv_sack_cache[4];
397 :
398 : struct sk_buff *highest_sack; /* highest skb with SACK received
399 : * (validity guaranteed only if
400 : * sacked_out > 0)
401 : */
402 :
403 : int lost_cnt_hint;
404 : u32 retransmit_high; /* L-bits may be on up to this seqno */
405 :
406 : u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */
407 :
408 : u32 prior_ssthresh; /* ssthresh saved at recovery start */
409 : u32 high_seq; /* snd_nxt at onset of congestion */
410 :
411 : u32 retrans_stamp; /* Timestamp of the last retransmit,
412 : * also used in SYN-SENT to remember stamp of
413 : * the first SYN. */
414 : u32 undo_marker; /* tracking retrans started here. */
415 : int undo_retrans; /* number of undoable retransmissions. */
416 : u32 total_retrans; /* Total retransmits for entire connection */
417 :
418 : u32 urg_seq; /* Seq of received urgent pointer */
419 : unsigned int keepalive_time; /* time before keep alive takes place */
420 : unsigned int keepalive_intvl; /* time interval between keep alive probes */
421 :
422 : int linger2;
423 :
424 : /* Receiver side RTT estimation */
425 : struct {
426 : u32 rtt;
427 : u32 seq;
428 : u32 time;
429 : } rcv_rtt_est;
430 :
431 : /* Receiver queue space */
432 : struct {
433 : int space;
434 : u32 seq;
435 : u32 time;
436 : } rcvq_space;
437 :
438 : /* TCP-specific MTU probe information. */
439 : struct {
440 : u32 probe_seq_start;
441 : u32 probe_seq_end;
442 : } mtu_probe;
443 :
444 : #ifdef CONFIG_TCP_MD5SIG
445 : /* TCP AF-Specific parts; only used by MD5 Signature support so far */
446 : const struct tcp_sock_af_ops *af_specific;
447 :
448 : /* TCP MD5 Signature Option information */
449 : struct tcp_md5sig_info *md5sig_info;
450 : #endif
451 :
452 : /* When the cookie options are generated and exchanged, then this
453 : * object holds a reference to them (cookie_values->kref). Also
454 : * contains related tcp_cookie_transactions fields.
455 : */
456 : struct tcp_cookie_values *cookie_values;
457 : };
458 :
459 : static inline struct tcp_sock *tcp_sk(const struct sock *sk)
460 : {
461 10 : return (struct tcp_sock *)sk;
462 : }
463 :
464 : struct tcp_timewait_sock {
465 : struct inet_timewait_sock tw_sk;
466 : u32 tw_rcv_nxt;
467 : u32 tw_snd_nxt;
468 : u32 tw_rcv_wnd;
469 : u32 tw_ts_recent;
470 : long tw_ts_recent_stamp;
471 : #ifdef CONFIG_TCP_MD5SIG
472 : u16 tw_md5_keylen;
473 : u8 tw_md5_key[TCP_MD5SIG_MAXKEYLEN];
474 : #endif
475 : /* Few sockets in timewait have cookies; in that case, then this
476 : * object holds a reference to them (tw_cookie_values->kref).
477 : */
478 : struct tcp_cookie_values *tw_cookie_values;
479 : };
480 :
481 : static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
482 : {
483 : return (struct tcp_timewait_sock *)sk;
484 : }
485 :
486 : #endif /* __KERNEL__ */
487 :
488 : #endif /* _LINUX_TCP_H */
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