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