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"
58 #define TCP_ACTION_FIN (1 << 7)
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)
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.
84 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
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)
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 */
114 #define TCPI_OPT_TIMESTAMPS 1
115 #define TCPI_OPT_SACK 2
116 #define TCPI_OPT_WSCALE 4
117 #define TCPI_OPT_ECN 8
122 #define TCPF_CA_Open (1<<TCP_CA_Open)
124 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
126 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
128 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
130 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
137 __u8 tcpi_retransmits;
141 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
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;
162 __u32 tcpi_rcv_ssthresh;
165 __u32 tcpi_snd_ssthresh;
168 __u32 tcpi_reordering;
171 __u32 tcpi_rcv_space;
173 __u32 tcpi_total_retrans;
178 #include <linux/config.h>
179 #include <linux/skbuff.h>
180 #include <linux/ip.h>
181 #include <net/sock.h>
183 /* This defines a selective acknowledgement block. */
184 struct tcp_sack_block {
189 struct tcp_options_received {
191 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
192 __u32 ts_recent; /* Time stamp to echo next */
193 __u32 rcv_tsval; /* Time stamp value */
194 __u32 rcv_tsecr; /* Time stamp echo reply */
195 __u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
196 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
197 dsack : 1, /* D-SACK is scheduled */
198 wscale_ok : 1, /* Wscale seen on SYN packet */
199 sack_ok : 4, /* SACK seen on SYN packet */
200 snd_wscale : 4, /* Window scaling received from sender */
201 rcv_wscale : 4; /* Window scaling to send to receiver */
203 __u8 eff_sacks; /* Size of SACK array to send with next packet */
204 __u8 num_sacks; /* Number of SACK blocks */
205 __u16 user_mss; /* mss requested by user in ioctl */
206 __u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
209 struct tcp_request_sock {
210 struct inet_request_sock req;
215 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
217 return (struct tcp_request_sock *)req;
221 /* inet_sock has to be the first member of tcp_sock */
222 struct inet_sock inet;
223 int tcp_header_len; /* Bytes of tcp header to send */
226 * Header prediction flags
227 * 0x5?10 << 16 + snd_wnd in net byte order
232 * RFC793 variables by their proper names. This means you can
233 * read the code and the spec side by side (and laugh ...)
234 * See RFC793 and RFC1122. The RFC writes these in capitals.
236 __u32 rcv_nxt; /* What we want to receive next */
237 __u32 snd_nxt; /* Next sequence we send */
239 __u32 snd_una; /* First byte we want an ack for */
240 __u32 snd_sml; /* Last byte of the most recently transmitted small packet */
241 __u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
242 __u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
243 /* Delayed ACK control data */
245 __u8 pending; /* ACK is pending */
246 __u8 quick; /* Scheduled number of quick acks */
247 __u8 pingpong; /* The session is interactive */
248 __u8 blocked; /* Delayed ACK was blocked by socket lock*/
249 __u32 ato; /* Predicted tick of soft clock */
250 unsigned long timeout; /* Currently scheduled timeout */
251 __u32 lrcvtime; /* timestamp of last received data packet*/
252 __u16 last_seg_size; /* Size of last incoming segment */
253 __u16 rcv_mss; /* MSS used for delayed ACK decisions */
256 /* Data for direct copy to user */
258 struct sk_buff_head prequeue;
259 struct task_struct *task;
265 __u32 snd_wl1; /* Sequence for window update */
266 __u32 snd_wnd; /* The window we expect to receive */
267 __u32 max_window; /* Maximal window ever seen from peer */
268 __u32 pmtu_cookie; /* Last pmtu seen by socket */
269 __u32 mss_cache; /* Cached effective mss, not including SACKS */
270 __u16 xmit_size_goal; /* Goal for segmenting output packets */
271 __u16 ext_header_len; /* Network protocol overhead (IP/IPv6 options) */
272 __u8 ca_state; /* State of fast-retransmit machine */
273 __u8 retransmits; /* Number of unrecovered RTO timeouts. */
275 __u16 advmss; /* Advertised MSS */
276 __u32 window_clamp; /* Maximal window to advertise */
277 __u32 rcv_ssthresh; /* Current window clamp */
279 __u32 frto_highmark; /* snd_nxt when RTO occurred */
280 __u8 reordering; /* Packet reordering metric. */
281 __u8 frto_counter; /* Number of new acks after RTO */
284 __u8 defer_accept; /* User waits for some data after accept() */
286 /* RTT measurement */
287 __u32 srtt; /* smoothed round trip time << 3 */
288 __u32 mdev; /* medium deviation */
289 __u32 mdev_max; /* maximal mdev for the last rtt period */
290 __u32 rttvar; /* smoothed mdev_max */
291 __u32 rtt_seq; /* sequence number to update rttvar */
292 __u32 rto; /* retransmit timeout */
294 __u32 packets_out; /* Packets which are "in flight" */
295 __u32 left_out; /* Packets which leaved network */
296 __u32 retrans_out; /* Retransmitted packets out */
297 __u8 backoff; /* backoff */
299 * Options received (usually on last packet, some only on SYN packets).
301 __u8 nonagle; /* Disable Nagle algorithm? */
302 __u8 keepalive_probes; /* num of allowed keep alive probes */
304 __u8 probes_out; /* unanswered 0 window probes */
305 struct tcp_options_received rx_opt;
308 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
310 __u32 snd_ssthresh; /* Slow start size threshold */
311 __u32 snd_cwnd; /* Sending congestion window */
312 __u16 snd_cwnd_cnt; /* Linear increase counter */
313 __u16 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
315 __u32 snd_cwnd_stamp;
317 /* Two commonly used timers in both sender and receiver paths. */
318 unsigned long timeout;
319 struct timer_list retransmit_timer; /* Resend (no ack) */
320 struct timer_list delack_timer; /* Ack delay */
322 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
324 struct tcp_func *af_specific; /* Operations which are AF_INET{4,6} specific */
326 __u32 rcv_wnd; /* Current receiver window */
327 __u32 rcv_wup; /* rcv_nxt on last window update sent */
328 __u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
329 __u32 pushed_seq; /* Last pushed seq, required to talk to windows */
330 __u32 copied_seq; /* Head of yet unread data */
333 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
334 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
336 __u8 syn_retries; /* num of allowed syn retries */
337 __u8 ecn_flags; /* ECN status bits. */
338 __u16 prior_ssthresh; /* ssthresh saved at recovery start */
339 __u32 lost_out; /* Lost packets */
340 __u32 sacked_out; /* SACK'd packets */
341 __u32 fackets_out; /* FACK'd packets */
342 __u32 high_seq; /* snd_nxt at onset of congestion */
344 __u32 retrans_stamp; /* Timestamp of the last retransmit,
345 * also used in SYN-SENT to remember stamp of
347 __u32 undo_marker; /* tracking retrans started here. */
348 int undo_retrans; /* number of undoable retransmissions. */
349 __u32 urg_seq; /* Seq of received urgent pointer */
350 __u16 urg_data; /* Saved octet of OOB data and control flags */
351 __u8 pending; /* Scheduled timer event */
352 __u8 urg_mode; /* In urgent mode */
353 __u32 snd_up; /* Urgent pointer */
355 __u32 total_retrans; /* Total retransmits for entire connection */
357 struct request_sock_queue accept_queue; /* FIFO of established children */
359 unsigned int keepalive_time; /* time before keep alive takes place */
360 unsigned int keepalive_intvl; /* time interval between keep alive probes */
363 unsigned long last_synq_overflow;
365 /* Receiver side RTT estimation */
372 /* Receiver queue space */
379 /* Pluggable TCP congestion control hook */
380 struct tcp_congestion_ops *ca_ops;
382 #define TCP_CA_PRIV_SIZE (16*sizeof(u32))
385 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
387 return (struct tcp_sock *)sk;
390 static inline void *tcp_ca(const struct tcp_sock *tp)
392 return (void *) tp->ca_priv;
397 #endif /* _LINUX_TCP_H */