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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
23struct tcphdr {
24 __u16 source;
25 __u16 dest;
26 __u32 seq;
27 __u32 ack_seq;
28#if defined(__LITTLE_ENDIAN_BITFIELD)
29 __u16 res1:4,
30 doff:4,
31 fin:1,
32 syn:1,
33 rst:1,
34 psh:1,
35 ack:1,
36 urg:1,
37 ece:1,
38 cwr:1;
39#elif defined(__BIG_ENDIAN_BITFIELD)
40 __u16 doff:4,
41 res1:4,
42 cwr:1,
43 ece:1,
44 urg:1,
45 ack:1,
46 psh:1,
47 rst:1,
48 syn:1,
49 fin:1;
50#else
51#error "Adjust your <asm/byteorder.h> defines"
52#endif
53 __u16 window;
54 __u16 check;
55 __u16 urg_ptr;
56};
57
58#define TCP_ACTION_FIN (1 << 7)
59
60enum {
61 TCPF_ESTABLISHED = (1 << 1),
62 TCPF_SYN_SENT = (1 << 2),
63 TCPF_SYN_RECV = (1 << 3),
64 TCPF_FIN_WAIT1 = (1 << 4),
65 TCPF_FIN_WAIT2 = (1 << 5),
66 TCPF_TIME_WAIT = (1 << 6),
67 TCPF_CLOSE = (1 << 7),
68 TCPF_CLOSE_WAIT = (1 << 8),
69 TCPF_LAST_ACK = (1 << 9),
70 TCPF_LISTEN = (1 << 10),
71 TCPF_CLOSING = (1 << 11)
72};
73
74/*
75 * The union cast uses a gcc extension to avoid aliasing problems
76 * (union is compatible to any of its members)
77 * This means this part of the code is -fstrict-aliasing safe now.
78 */
79union tcp_word_hdr {
80 struct tcphdr hdr;
81 __u32 words[5];
82};
83
84#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
85
86enum {
87 TCP_FLAG_CWR = __constant_htonl(0x00800000),
88 TCP_FLAG_ECE = __constant_htonl(0x00400000),
89 TCP_FLAG_URG = __constant_htonl(0x00200000),
90 TCP_FLAG_ACK = __constant_htonl(0x00100000),
91 TCP_FLAG_PSH = __constant_htonl(0x00080000),
92 TCP_FLAG_RST = __constant_htonl(0x00040000),
93 TCP_FLAG_SYN = __constant_htonl(0x00020000),
94 TCP_FLAG_FIN = __constant_htonl(0x00010000),
95 TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
96 TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
97};
98
99/* TCP socket options */
100#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
101#define TCP_MAXSEG 2 /* Limit MSS */
102#define TCP_CORK 3 /* Never send partially complete segments */
103#define TCP_KEEPIDLE 4 /* Start keeplives after this period */
104#define TCP_KEEPINTVL 5 /* Interval between keepalives */
105#define TCP_KEEPCNT 6 /* Number of keepalives before death */
106#define TCP_SYNCNT 7 /* Number of SYN retransmits */
107#define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
108#define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
109#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
110#define TCP_INFO 11 /* Information about this connection. */
111#define TCP_QUICKACK 12 /* Block/reenable quick acks */
112#define TCP_CONGESTION 13 /* Congestion control algorithm */
113
114#define TCPI_OPT_TIMESTAMPS 1
115#define TCPI_OPT_SACK 2
116#define TCPI_OPT_WSCALE 4
117#define TCPI_OPT_ECN 8
118
119enum tcp_ca_state
120{
121 TCP_CA_Open = 0,
122#define TCPF_CA_Open (1<<TCP_CA_Open)
123 TCP_CA_Disorder = 1,
124#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
125 TCP_CA_CWR = 2,
126#define TCPF_CA_CWR (1<<TCP_CA_CWR)
127 TCP_CA_Recovery = 3,
128#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
129 TCP_CA_Loss = 4
130#define TCPF_CA_Loss (1<<TCP_CA_Loss)
131};
132
133struct tcp_info
134{
135 __u8 tcpi_state;
136 __u8 tcpi_ca_state;
137 __u8 tcpi_retransmits;
138 __u8 tcpi_probes;
139 __u8 tcpi_backoff;
140 __u8 tcpi_options;
141 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
142
143 __u32 tcpi_rto;
144 __u32 tcpi_ato;
145 __u32 tcpi_snd_mss;
146 __u32 tcpi_rcv_mss;
147
148 __u32 tcpi_unacked;
149 __u32 tcpi_sacked;
150 __u32 tcpi_lost;
151 __u32 tcpi_retrans;
152 __u32 tcpi_fackets;
153
154 /* Times. */
155 __u32 tcpi_last_data_sent;
156 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
157 __u32 tcpi_last_data_recv;
158 __u32 tcpi_last_ack_recv;
159
160 /* Metrics. */
161 __u32 tcpi_pmtu;
162 __u32 tcpi_rcv_ssthresh;
163 __u32 tcpi_rtt;
164 __u32 tcpi_rttvar;
165 __u32 tcpi_snd_ssthresh;
166 __u32 tcpi_snd_cwnd;
167 __u32 tcpi_advmss;
168 __u32 tcpi_reordering;
169
170 __u32 tcpi_rcv_rtt;
171 __u32 tcpi_rcv_space;
172
173 __u32 tcpi_total_retrans;
174};
175
176#ifdef __KERNEL__
177
178#include <linux/config.h>
179#include <linux/skbuff.h>
180#include <net/sock.h>
181#include <net/inet_connection_sock.h>
182#include <net/inet_timewait_sock.h>
183
184/* This defines a selective acknowledgement block. */
185struct tcp_sack_block {
186 __u32 start_seq;
187 __u32 end_seq;
188};
189
190struct tcp_options_received {
191/* PAWS/RTTM data */
192 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
193 __u32 ts_recent; /* Time stamp to echo next */
194 __u32 rcv_tsval; /* Time stamp value */
195 __u32 rcv_tsecr; /* Time stamp echo reply */
196 __u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
197 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
198 dsack : 1, /* D-SACK is scheduled */
199 wscale_ok : 1, /* Wscale seen on SYN packet */
200 sack_ok : 4, /* SACK seen on SYN packet */
201 snd_wscale : 4, /* Window scaling received from sender */
202 rcv_wscale : 4; /* Window scaling to send to receiver */
203/* SACKs data */
204 __u8 eff_sacks; /* Size of SACK array to send with next packet */
205 __u8 num_sacks; /* Number of SACK blocks */
206 __u16 user_mss; /* mss requested by user in ioctl */
207 __u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
208};
209
210struct tcp_request_sock {
211 struct inet_request_sock req;
212 __u32 rcv_isn;
213 __u32 snt_isn;
214};
215
216static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
217{
218 return (struct tcp_request_sock *)req;
219}
220
221struct tcp_sock {
222 /* inet_connection_sock has to be the first member of tcp_sock */
223 struct inet_connection_sock inet_conn;
224 int tcp_header_len; /* Bytes of tcp header to send */
225
226/*
227 * Header prediction flags
228 * 0x5?10 << 16 + snd_wnd in net byte order
229 */
230 __u32 pred_flags;
231
232/*
233 * RFC793 variables by their proper names. This means you can
234 * read the code and the spec side by side (and laugh ...)
235 * See RFC793 and RFC1122. The RFC writes these in capitals.
236 */
237 __u32 rcv_nxt; /* What we want to receive next */
238 __u32 snd_nxt; /* Next sequence we send */
239
240 __u32 snd_una; /* First byte we want an ack for */
241 __u32 snd_sml; /* Last byte of the most recently transmitted small packet */
242 __u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
243 __u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
244
245 /* Data for direct copy to user */
246 struct {
247 struct sk_buff_head prequeue;
248 struct task_struct *task;
249 struct iovec *iov;
250 int memory;
251 int len;
252 } ucopy;
253
254 __u32 snd_wl1; /* Sequence for window update */
255 __u32 snd_wnd; /* The window we expect to receive */
256 __u32 max_window; /* Maximal window ever seen from peer */
257 __u32 pmtu_cookie; /* Last pmtu seen by socket */
258 __u32 mss_cache; /* Cached effective mss, not including SACKS */
259 __u16 xmit_size_goal; /* Goal for segmenting output packets */
260 __u16 ext_header_len; /* Network protocol overhead (IP/IPv6 options) */
261
262 __u32 window_clamp; /* Maximal window to advertise */
263 __u32 rcv_ssthresh; /* Current window clamp */
264
265 __u32 frto_highmark; /* snd_nxt when RTO occurred */
266 __u8 reordering; /* Packet reordering metric. */
267 __u8 frto_counter; /* Number of new acks after RTO */
268 __u8 nonagle; /* Disable Nagle algorithm? */
269 __u8 keepalive_probes; /* num of allowed keep alive probes */
270
271/* RTT measurement */
272 __u32 srtt; /* smoothed round trip time << 3 */
273 __u32 mdev; /* medium deviation */
274 __u32 mdev_max; /* maximal mdev for the last rtt period */
275 __u32 rttvar; /* smoothed mdev_max */
276 __u32 rtt_seq; /* sequence number to update rttvar */
277
278 __u32 packets_out; /* Packets which are "in flight" */
279 __u32 left_out; /* Packets which leaved network */
280 __u32 retrans_out; /* Retransmitted packets out */
281/*
282 * Options received (usually on last packet, some only on SYN packets).
283 */
284 struct tcp_options_received rx_opt;
285
286/*
287 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
288 */
289 __u32 snd_ssthresh; /* Slow start size threshold */
290 __u32 snd_cwnd; /* Sending congestion window */
291 __u16 snd_cwnd_cnt; /* Linear increase counter */
292 __u16 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
293 __u32 snd_cwnd_used;
294 __u32 snd_cwnd_stamp;
295
296 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
297
298 struct tcp_func *af_specific; /* Operations which are AF_INET{4,6} specific */
299
300 __u32 rcv_wnd; /* Current receiver window */
301 __u32 rcv_wup; /* rcv_nxt on last window update sent */
302 __u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
303 __u32 pushed_seq; /* Last pushed seq, required to talk to windows */
304 __u32 copied_seq; /* Head of yet unread data */
305
306/* SACKs data */
307 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
308 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
309
310 __u16 advmss; /* Advertised MSS */
311 __u16 prior_ssthresh; /* ssthresh saved at recovery start */
312 __u32 lost_out; /* Lost packets */
313 __u32 sacked_out; /* SACK'd packets */
314 __u32 fackets_out; /* FACK'd packets */
315 __u32 high_seq; /* snd_nxt at onset of congestion */
316
317 __u32 retrans_stamp; /* Timestamp of the last retransmit,
318 * also used in SYN-SENT to remember stamp of
319 * the first SYN. */
320 __u32 undo_marker; /* tracking retrans started here. */
321 int undo_retrans; /* number of undoable retransmissions. */
322 __u32 urg_seq; /* Seq of received urgent pointer */
323 __u16 urg_data; /* Saved octet of OOB data and control flags */
324 __u8 urg_mode; /* In urgent mode */
325 __u8 ecn_flags; /* ECN status bits. */
326 __u32 snd_up; /* Urgent pointer */
327
328 __u32 total_retrans; /* Total retransmits for entire connection */
329
330 unsigned int keepalive_time; /* time before keep alive takes place */
331 unsigned int keepalive_intvl; /* time interval between keep alive probes */
332 int linger2;
333
334 unsigned long last_synq_overflow;
335
336/* Receiver side RTT estimation */
337 struct {
338 __u32 rtt;
339 __u32 seq;
340 __u32 time;
341 } rcv_rtt_est;
342
343/* Receiver queue space */
344 struct {
345 int space;
346 __u32 seq;
347 __u32 time;
348 } rcvq_space;
349};
350
351static inline struct tcp_sock *tcp_sk(const struct sock *sk)
352{
353 return (struct tcp_sock *)sk;
354}
355
356struct tcp_timewait_sock {
357 struct inet_timewait_sock tw_sk;
358 __u32 tw_rcv_nxt;
359 __u32 tw_snd_nxt;
360 __u32 tw_rcv_wnd;
361 __u32 tw_ts_recent;
362 long tw_ts_recent_stamp;
363};
364
365static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
366{
367 return (struct tcp_timewait_sock *)sk;
368}
369
370#endif
371
372#endif /* _LINUX_TCP_H */