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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/*
59 * The union cast uses a gcc extension to avoid aliasing problems
60 * (union is compatible to any of its members)
61 * This means this part of the code is -fstrict-aliasing safe now.
62 */
63union tcp_word_hdr {
64 struct tcphdr hdr;
65 __u32 words[5];
66};
67
68#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
69
70enum {
71 TCP_FLAG_CWR = __constant_htonl(0x00800000),
72 TCP_FLAG_ECE = __constant_htonl(0x00400000),
73 TCP_FLAG_URG = __constant_htonl(0x00200000),
74 TCP_FLAG_ACK = __constant_htonl(0x00100000),
75 TCP_FLAG_PSH = __constant_htonl(0x00080000),
76 TCP_FLAG_RST = __constant_htonl(0x00040000),
77 TCP_FLAG_SYN = __constant_htonl(0x00020000),
78 TCP_FLAG_FIN = __constant_htonl(0x00010000),
79 TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
80 TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
81};
82
83/* TCP socket options */
84#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
85#define TCP_MAXSEG 2 /* Limit MSS */
86#define TCP_CORK 3 /* Never send partially complete segments */
87#define TCP_KEEPIDLE 4 /* Start keeplives after this period */
88#define TCP_KEEPINTVL 5 /* Interval between keepalives */
89#define TCP_KEEPCNT 6 /* Number of keepalives before death */
90#define TCP_SYNCNT 7 /* Number of SYN retransmits */
91#define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
92#define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
93#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
94#define TCP_INFO 11 /* Information about this connection. */
95#define TCP_QUICKACK 12 /* Block/reenable quick acks */
96#define TCP_CONGESTION 13 /* Congestion control algorithm */
97
98#define TCPI_OPT_TIMESTAMPS 1
99#define TCPI_OPT_SACK 2
100#define TCPI_OPT_WSCALE 4
101#define TCPI_OPT_ECN 8
102
103enum tcp_ca_state
104{
105 TCP_CA_Open = 0,
106#define TCPF_CA_Open (1<<TCP_CA_Open)
107 TCP_CA_Disorder = 1,
108#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
109 TCP_CA_CWR = 2,
110#define TCPF_CA_CWR (1<<TCP_CA_CWR)
111 TCP_CA_Recovery = 3,
112#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
113 TCP_CA_Loss = 4
114#define TCPF_CA_Loss (1<<TCP_CA_Loss)
115};
116
117struct tcp_info
118{
119 __u8 tcpi_state;
120 __u8 tcpi_ca_state;
121 __u8 tcpi_retransmits;
122 __u8 tcpi_probes;
123 __u8 tcpi_backoff;
124 __u8 tcpi_options;
125 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
126
127 __u32 tcpi_rto;
128 __u32 tcpi_ato;
129 __u32 tcpi_snd_mss;
130 __u32 tcpi_rcv_mss;
131
132 __u32 tcpi_unacked;
133 __u32 tcpi_sacked;
134 __u32 tcpi_lost;
135 __u32 tcpi_retrans;
136 __u32 tcpi_fackets;
137
138 /* Times. */
139 __u32 tcpi_last_data_sent;
140 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
141 __u32 tcpi_last_data_recv;
142 __u32 tcpi_last_ack_recv;
143
144 /* Metrics. */
145 __u32 tcpi_pmtu;
146 __u32 tcpi_rcv_ssthresh;
147 __u32 tcpi_rtt;
148 __u32 tcpi_rttvar;
149 __u32 tcpi_snd_ssthresh;
150 __u32 tcpi_snd_cwnd;
151 __u32 tcpi_advmss;
152 __u32 tcpi_reordering;
153
154 __u32 tcpi_rcv_rtt;
155 __u32 tcpi_rcv_space;
156
157 __u32 tcpi_total_retrans;
158};
159
160#ifdef __KERNEL__
161
162#include <linux/config.h>
163#include <linux/skbuff.h>
164#include <net/sock.h>
165#include <net/inet_connection_sock.h>
166#include <net/inet_timewait_sock.h>
167
168/* This defines a selective acknowledgement block. */
169struct tcp_sack_block {
170 __u32 start_seq;
171 __u32 end_seq;
172};
173
174struct tcp_options_received {
175/* PAWS/RTTM data */
176 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
177 __u32 ts_recent; /* Time stamp to echo next */
178 __u32 rcv_tsval; /* Time stamp value */
179 __u32 rcv_tsecr; /* Time stamp echo reply */
180 __u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
181 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
182 dsack : 1, /* D-SACK is scheduled */
183 wscale_ok : 1, /* Wscale seen on SYN packet */
184 sack_ok : 4, /* SACK seen on SYN packet */
185 snd_wscale : 4, /* Window scaling received from sender */
186 rcv_wscale : 4; /* Window scaling to send to receiver */
187/* SACKs data */
188 __u8 eff_sacks; /* Size of SACK array to send with next packet */
189 __u8 num_sacks; /* Number of SACK blocks */
190 __u16 user_mss; /* mss requested by user in ioctl */
191 __u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
192};
193
194struct tcp_request_sock {
195 struct inet_request_sock req;
196 __u32 rcv_isn;
197 __u32 snt_isn;
198};
199
200static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
201{
202 return (struct tcp_request_sock *)req;
203}
204
205struct tcp_sock {
206 /* inet_connection_sock has to be the first member of tcp_sock */
207 struct inet_connection_sock inet_conn;
208 int tcp_header_len; /* Bytes of tcp header to send */
209
210/*
211 * Header prediction flags
212 * 0x5?10 << 16 + snd_wnd in net byte order
213 */
214 __u32 pred_flags;
215
216/*
217 * RFC793 variables by their proper names. This means you can
218 * read the code and the spec side by side (and laugh ...)
219 * See RFC793 and RFC1122. The RFC writes these in capitals.
220 */
221 __u32 rcv_nxt; /* What we want to receive next */
222 __u32 snd_nxt; /* Next sequence we send */
223
224 __u32 snd_una; /* First byte we want an ack for */
225 __u32 snd_sml; /* Last byte of the most recently transmitted small packet */
226 __u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
227 __u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
228
229 /* Data for direct copy to user */
230 struct {
231 struct sk_buff_head prequeue;
232 struct task_struct *task;
233 struct iovec *iov;
234 int memory;
235 int len;
236 } ucopy;
237
238 __u32 snd_wl1; /* Sequence for window update */
239 __u32 snd_wnd; /* The window we expect to receive */
240 __u32 max_window; /* Maximal window ever seen from peer */
241 __u32 mss_cache; /* Cached effective mss, not including SACKS */
242 __u16 xmit_size_goal; /* Goal for segmenting output packets */
243 /* XXX Two bytes hole, try to pack */
244
245 __u32 window_clamp; /* Maximal window to advertise */
246 __u32 rcv_ssthresh; /* Current window clamp */
247
248 __u32 frto_highmark; /* snd_nxt when RTO occurred */
249 __u8 reordering; /* Packet reordering metric. */
250 __u8 frto_counter; /* Number of new acks after RTO */
251 __u8 nonagle; /* Disable Nagle algorithm? */
252 __u8 keepalive_probes; /* num of allowed keep alive probes */
253
254/* RTT measurement */
255 __u32 srtt; /* smoothed round trip time << 3 */
256 __u32 mdev; /* medium deviation */
257 __u32 mdev_max; /* maximal mdev for the last rtt period */
258 __u32 rttvar; /* smoothed mdev_max */
259 __u32 rtt_seq; /* sequence number to update rttvar */
260
261 __u32 packets_out; /* Packets which are "in flight" */
262 __u32 left_out; /* Packets which leaved network */
263 __u32 retrans_out; /* Retransmitted packets out */
264/*
265 * Options received (usually on last packet, some only on SYN packets).
266 */
267 struct tcp_options_received rx_opt;
268
269/*
270 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
271 */
272 __u32 snd_ssthresh; /* Slow start size threshold */
273 __u32 snd_cwnd; /* Sending congestion window */
274 __u16 snd_cwnd_cnt; /* Linear increase counter */
275 __u16 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
276 __u32 snd_cwnd_used;
277 __u32 snd_cwnd_stamp;
278
279 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
280
281 __u32 rcv_wnd; /* Current receiver window */
282 __u32 rcv_wup; /* rcv_nxt on last window update sent */
283 __u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
284 __u32 pushed_seq; /* Last pushed seq, required to talk to windows */
285 __u32 copied_seq; /* Head of yet unread data */
286
287/* SACKs data */
288 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
289 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
290
291 struct tcp_sack_block recv_sack_cache[4];
292
293 /* from STCP, retrans queue hinting */
294 struct sk_buff* lost_skb_hint;
295
296 struct sk_buff *scoreboard_skb_hint;
297 struct sk_buff *retransmit_skb_hint;
298 struct sk_buff *forward_skb_hint;
299 struct sk_buff *fastpath_skb_hint;
300
301 int fastpath_cnt_hint;
302 int lost_cnt_hint;
303 int retransmit_cnt_hint;
304 int forward_cnt_hint;
305
306 __u16 advmss; /* Advertised MSS */
307 __u16 prior_ssthresh; /* ssthresh saved at recovery start */
308 __u32 lost_out; /* Lost packets */
309 __u32 sacked_out; /* SACK'd packets */
310 __u32 fackets_out; /* FACK'd packets */
311 __u32 high_seq; /* snd_nxt at onset of congestion */
312
313 __u32 retrans_stamp; /* Timestamp of the last retransmit,
314 * also used in SYN-SENT to remember stamp of
315 * the first SYN. */
316 __u32 undo_marker; /* tracking retrans started here. */
317 int undo_retrans; /* number of undoable retransmissions. */
318 __u32 urg_seq; /* Seq of received urgent pointer */
319 __u16 urg_data; /* Saved octet of OOB data and control flags */
320 __u8 urg_mode; /* In urgent mode */
321 __u8 ecn_flags; /* ECN status bits. */
322 __u32 snd_up; /* Urgent pointer */
323
324 __u32 total_retrans; /* Total retransmits for entire connection */
325 __u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */
326
327 unsigned int keepalive_time; /* time before keep alive takes place */
328 unsigned int keepalive_intvl; /* time interval between keep alive probes */
329 int linger2;
330
331 unsigned long last_synq_overflow;
332
333/* Receiver side RTT estimation */
334 struct {
335 __u32 rtt;
336 __u32 seq;
337 __u32 time;
338 } rcv_rtt_est;
339
340/* Receiver queue space */
341 struct {
342 int space;
343 __u32 seq;
344 __u32 time;
345 } rcvq_space;
346
347/* TCP-specific MTU probe information. */
348 struct {
349 __u32 probe_seq_start;
350 __u32 probe_seq_end;
351 } mtu_probe;
352};
353
354static inline struct tcp_sock *tcp_sk(const struct sock *sk)
355{
356 return (struct tcp_sock *)sk;
357}
358
359struct tcp_timewait_sock {
360 struct inet_timewait_sock tw_sk;
361 __u32 tw_rcv_nxt;
362 __u32 tw_snd_nxt;
363 __u32 tw_rcv_wnd;
364 __u32 tw_ts_recent;
365 long tw_ts_recent_stamp;
366};
367
368static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
369{
370 return (struct tcp_timewait_sock *)sk;
371}
372
373#endif
374
375#endif /* _LINUX_TCP_H */