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.
6 * Definitions for the TCP protocol.
8 * Version: @(#)tcp.h 1.0.2 04/28/93
10 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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.
20 #include <linux/types.h>
21 #include <asm/byteorder.h>
28 #if defined(__LITTLE_ENDIAN_BITFIELD)
39 #elif defined(__BIG_ENDIAN_BITFIELD)
51 #error "Adjust your <asm/byteorder.h> defines"
70 TCP_CLOSING, /* now a valid state */
72 TCP_MAX_STATES /* Leave at the end! */
75 #define TCP_STATE_MASK 0xF
76 #define TCP_ACTION_FIN (1 << 7)
79 TCPF_ESTABLISHED = (1 << 1),
80 TCPF_SYN_SENT = (1 << 2),
81 TCPF_SYN_RECV = (1 << 3),
82 TCPF_FIN_WAIT1 = (1 << 4),
83 TCPF_FIN_WAIT2 = (1 << 5),
84 TCPF_TIME_WAIT = (1 << 6),
85 TCPF_CLOSE = (1 << 7),
86 TCPF_CLOSE_WAIT = (1 << 8),
87 TCPF_LAST_ACK = (1 << 9),
88 TCPF_LISTEN = (1 << 10),
89 TCPF_CLOSING = (1 << 11)
93 * The union cast uses a gcc extension to avoid aliasing problems
94 * (union is compatible to any of its members)
95 * This means this part of the code is -fstrict-aliasing safe now.
102 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
105 TCP_FLAG_CWR = __constant_htonl(0x00800000),
106 TCP_FLAG_ECE = __constant_htonl(0x00400000),
107 TCP_FLAG_URG = __constant_htonl(0x00200000),
108 TCP_FLAG_ACK = __constant_htonl(0x00100000),
109 TCP_FLAG_PSH = __constant_htonl(0x00080000),
110 TCP_FLAG_RST = __constant_htonl(0x00040000),
111 TCP_FLAG_SYN = __constant_htonl(0x00020000),
112 TCP_FLAG_FIN = __constant_htonl(0x00010000),
113 TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
114 TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
117 /* TCP socket options */
118 #define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
119 #define TCP_MAXSEG 2 /* Limit MSS */
120 #define TCP_CORK 3 /* Never send partially complete segments */
121 #define TCP_KEEPIDLE 4 /* Start keeplives after this period */
122 #define TCP_KEEPINTVL 5 /* Interval between keepalives */
123 #define TCP_KEEPCNT 6 /* Number of keepalives before death */
124 #define TCP_SYNCNT 7 /* Number of SYN retransmits */
125 #define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
126 #define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
127 #define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
128 #define TCP_INFO 11 /* Information about this connection. */
129 #define TCP_QUICKACK 12 /* Block/reenable quick acks */
131 #define TCPI_OPT_TIMESTAMPS 1
132 #define TCPI_OPT_SACK 2
133 #define TCPI_OPT_WSCALE 4
134 #define TCPI_OPT_ECN 8
139 #define TCPF_CA_Open (1<<TCP_CA_Open)
141 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
143 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
145 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
147 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
154 __u8 tcpi_retransmits;
158 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
172 __u32 tcpi_last_data_sent;
173 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
174 __u32 tcpi_last_data_recv;
175 __u32 tcpi_last_ack_recv;
179 __u32 tcpi_rcv_ssthresh;
182 __u32 tcpi_snd_ssthresh;
185 __u32 tcpi_reordering;
188 __u32 tcpi_rcv_space;
190 __u32 tcpi_total_retrans;
195 #include <linux/config.h>
196 #include <linux/skbuff.h>
197 #include <linux/ip.h>
198 #include <net/sock.h>
200 /* This defines a selective acknowledgement block. */
201 struct tcp_sack_block {
206 struct tcp_options_received {
208 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
209 __u32 ts_recent; /* Time stamp to echo next */
210 __u32 rcv_tsval; /* Time stamp value */
211 __u32 rcv_tsecr; /* Time stamp echo reply */
212 __u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
213 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
214 dsack : 1, /* D-SACK is scheduled */
215 wscale_ok : 1, /* Wscale seen on SYN packet */
216 sack_ok : 4, /* SACK seen on SYN packet */
217 snd_wscale : 4, /* Window scaling received from sender */
218 rcv_wscale : 4; /* Window scaling to send to receiver */
220 __u8 eff_sacks; /* Size of SACK array to send with next packet */
221 __u8 num_sacks; /* Number of SACK blocks */
222 __u16 user_mss; /* mss requested by user in ioctl */
223 __u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
226 struct tcp_request_sock {
227 struct inet_request_sock req;
232 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
234 return (struct tcp_request_sock *)req;
238 /* inet_sock has to be the first member of tcp_sock */
239 struct inet_sock inet;
240 int tcp_header_len; /* Bytes of tcp header to send */
243 * Header prediction flags
244 * 0x5?10 << 16 + snd_wnd in net byte order
249 * RFC793 variables by their proper names. This means you can
250 * read the code and the spec side by side (and laugh ...)
251 * See RFC793 and RFC1122. The RFC writes these in capitals.
253 __u32 rcv_nxt; /* What we want to receive next */
254 __u32 snd_nxt; /* Next sequence we send */
256 __u32 snd_una; /* First byte we want an ack for */
257 __u32 snd_sml; /* Last byte of the most recently transmitted small packet */
258 __u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
259 __u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
260 struct tcp_bind_bucket *bind_hash;
261 /* Delayed ACK control data */
263 __u8 pending; /* ACK is pending */
264 __u8 quick; /* Scheduled number of quick acks */
265 __u8 pingpong; /* The session is interactive */
266 __u8 blocked; /* Delayed ACK was blocked by socket lock*/
267 __u32 ato; /* Predicted tick of soft clock */
268 unsigned long timeout; /* Currently scheduled timeout */
269 __u32 lrcvtime; /* timestamp of last received data packet*/
270 __u16 last_seg_size; /* Size of last incoming segment */
271 __u16 rcv_mss; /* MSS used for delayed ACK decisions */
274 /* Data for direct copy to user */
276 struct sk_buff_head prequeue;
277 struct task_struct *task;
283 __u32 snd_wl1; /* Sequence for window update */
284 __u32 snd_wnd; /* The window we expect to receive */
285 __u32 max_window; /* Maximal window ever seen from peer */
286 __u32 pmtu_cookie; /* Last pmtu seen by socket */
287 __u32 mss_cache; /* Cached effective mss, not including SACKS */
288 __u16 mss_cache_std; /* Like mss_cache, but without TSO */
289 __u16 ext_header_len; /* Network protocol overhead (IP/IPv6 options) */
290 __u8 ca_state; /* State of fast-retransmit machine */
291 __u8 retransmits; /* Number of unrecovered RTO timeouts. */
293 __u16 advmss; /* Advertised MSS */
294 __u32 window_clamp; /* Maximal window to advertise */
295 __u32 rcv_ssthresh; /* Current window clamp */
297 __u32 frto_highmark; /* snd_nxt when RTO occurred */
298 __u8 reordering; /* Packet reordering metric. */
299 __u8 frto_counter; /* Number of new acks after RTO */
302 __u8 defer_accept; /* User waits for some data after accept() */
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 __u32 rto; /* retransmit timeout */
312 __u32 packets_out; /* Packets which are "in flight" */
313 __u32 left_out; /* Packets which leaved network */
314 __u32 retrans_out; /* Retransmitted packets out */
315 __u8 backoff; /* backoff */
317 * Options received (usually on last packet, some only on SYN packets).
319 __u8 nonagle; /* Disable Nagle algorithm? */
320 __u8 keepalive_probes; /* num of allowed keep alive probes */
322 __u8 probes_out; /* unanswered 0 window probes */
323 struct tcp_options_received rx_opt;
326 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
328 __u32 snd_ssthresh; /* Slow start size threshold */
329 __u32 snd_cwnd; /* Sending congestion window */
330 __u16 snd_cwnd_cnt; /* Linear increase counter */
331 __u16 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
333 __u32 snd_cwnd_stamp;
335 /* Two commonly used timers in both sender and receiver paths. */
336 unsigned long timeout;
337 struct timer_list retransmit_timer; /* Resend (no ack) */
338 struct timer_list delack_timer; /* Ack delay */
340 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
342 struct tcp_func *af_specific; /* Operations which are AF_INET{4,6} specific */
344 __u32 rcv_wnd; /* Current receiver window */
345 __u32 rcv_wup; /* rcv_nxt on last window update sent */
346 __u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
347 __u32 pushed_seq; /* Last pushed seq, required to talk to windows */
348 __u32 copied_seq; /* Head of yet unread data */
351 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
352 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
354 __u8 syn_retries; /* num of allowed syn retries */
355 __u8 ecn_flags; /* ECN status bits. */
356 __u16 prior_ssthresh; /* ssthresh saved at recovery start */
357 __u32 lost_out; /* Lost packets */
358 __u32 sacked_out; /* SACK'd packets */
359 __u32 fackets_out; /* FACK'd packets */
360 __u32 high_seq; /* snd_nxt at onset of congestion */
362 __u32 retrans_stamp; /* Timestamp of the last retransmit,
363 * also used in SYN-SENT to remember stamp of
365 __u32 undo_marker; /* tracking retrans started here. */
366 int undo_retrans; /* number of undoable retransmissions. */
367 __u32 urg_seq; /* Seq of received urgent pointer */
368 __u16 urg_data; /* Saved octet of OOB data and control flags */
369 __u8 pending; /* Scheduled timer event */
370 __u8 urg_mode; /* In urgent mode */
371 __u32 snd_up; /* Urgent pointer */
373 __u32 total_retrans; /* Total retransmits for entire connection */
375 struct request_sock_queue accept_queue; /* FIFO of established children */
377 unsigned int keepalive_time; /* time before keep alive takes place */
378 unsigned int keepalive_intvl; /* time interval between keep alive probes */
381 unsigned long last_synq_overflow;
383 /* Receiver side RTT estimation */
390 /* Receiver queue space */
397 /* Pluggable TCP congestion control hook */
398 struct tcp_congestion_ops *ca_ops;
400 #define TCP_CA_PRIV_SIZE (16*sizeof(u32))
403 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
405 return (struct tcp_sock *)sk;
408 static inline void *tcp_ca(const struct tcp_sock *tp)
410 return (void *) tp->ca_priv;
415 #endif /* _LINUX_TCP_H */