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"
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.
68 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
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)
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 */
98 #define TCPI_OPT_TIMESTAMPS 1
99 #define TCPI_OPT_SACK 2
100 #define TCPI_OPT_WSCALE 4
101 #define TCPI_OPT_ECN 8
106 #define TCPF_CA_Open (1<<TCP_CA_Open)
108 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
110 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
112 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
114 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
121 __u8 tcpi_retransmits;
125 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
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;
146 __u32 tcpi_rcv_ssthresh;
149 __u32 tcpi_snd_ssthresh;
152 __u32 tcpi_reordering;
155 __u32 tcpi_rcv_space;
157 __u32 tcpi_total_retrans;
162 #include <linux/skbuff.h>
163 #include <net/sock.h>
164 #include <net/inet_connection_sock.h>
165 #include <net/inet_timewait_sock.h>
167 /* This defines a selective acknowledgement block. */
168 struct tcp_sack_block {
173 struct tcp_options_received {
175 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
176 __u32 ts_recent; /* Time stamp to echo next */
177 __u32 rcv_tsval; /* Time stamp value */
178 __u32 rcv_tsecr; /* Time stamp echo reply */
179 __u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
180 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
181 dsack : 1, /* D-SACK is scheduled */
182 wscale_ok : 1, /* Wscale seen on SYN packet */
183 sack_ok : 4, /* SACK seen on SYN packet */
184 snd_wscale : 4, /* Window scaling received from sender */
185 rcv_wscale : 4; /* Window scaling to send to receiver */
187 __u8 eff_sacks; /* Size of SACK array to send with next packet */
188 __u8 num_sacks; /* Number of SACK blocks */
189 __u16 user_mss; /* mss requested by user in ioctl */
190 __u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
193 struct tcp_request_sock {
194 struct inet_request_sock req;
199 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
201 return (struct tcp_request_sock *)req;
205 /* inet_connection_sock has to be the first member of tcp_sock */
206 struct inet_connection_sock inet_conn;
207 int tcp_header_len; /* Bytes of tcp header to send */
210 * Header prediction flags
211 * 0x5?10 << 16 + snd_wnd in net byte order
216 * RFC793 variables by their proper names. This means you can
217 * read the code and the spec side by side (and laugh ...)
218 * See RFC793 and RFC1122. The RFC writes these in capitals.
220 __u32 rcv_nxt; /* What we want to receive next */
221 __u32 snd_nxt; /* Next sequence we send */
223 __u32 snd_una; /* First byte we want an ack for */
224 __u32 snd_sml; /* Last byte of the most recently transmitted small packet */
225 __u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
226 __u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
228 /* Data for direct copy to user */
230 struct sk_buff_head prequeue;
231 struct task_struct *task;
237 __u32 snd_wl1; /* Sequence for window update */
238 __u32 snd_wnd; /* The window we expect to receive */
239 __u32 max_window; /* Maximal window ever seen from peer */
240 __u32 mss_cache; /* Cached effective mss, not including SACKS */
241 __u16 xmit_size_goal; /* Goal for segmenting output packets */
242 /* XXX Two bytes hole, try to pack */
244 __u32 window_clamp; /* Maximal window to advertise */
245 __u32 rcv_ssthresh; /* Current window clamp */
247 __u32 frto_highmark; /* snd_nxt when RTO occurred */
248 __u8 reordering; /* Packet reordering metric. */
249 __u8 frto_counter; /* Number of new acks after RTO */
250 __u8 nonagle; /* Disable Nagle algorithm? */
251 __u8 keepalive_probes; /* num of allowed keep alive probes */
253 /* RTT measurement */
254 __u32 srtt; /* smoothed round trip time << 3 */
255 __u32 mdev; /* medium deviation */
256 __u32 mdev_max; /* maximal mdev for the last rtt period */
257 __u32 rttvar; /* smoothed mdev_max */
258 __u32 rtt_seq; /* sequence number to update rttvar */
260 __u32 packets_out; /* Packets which are "in flight" */
261 __u32 left_out; /* Packets which leaved network */
262 __u32 retrans_out; /* Retransmitted packets out */
264 * Options received (usually on last packet, some only on SYN packets).
266 struct tcp_options_received rx_opt;
269 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
271 __u32 snd_ssthresh; /* Slow start size threshold */
272 __u32 snd_cwnd; /* Sending congestion window */
273 __u16 snd_cwnd_cnt; /* Linear increase counter */
274 __u16 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
276 __u32 snd_cwnd_stamp;
278 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
280 __u32 rcv_wnd; /* Current receiver window */
281 __u32 rcv_wup; /* rcv_nxt on last window update sent */
282 __u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
283 __u32 pushed_seq; /* Last pushed seq, required to talk to windows */
284 __u32 copied_seq; /* Head of yet unread data */
287 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
288 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
290 struct tcp_sack_block recv_sack_cache[4];
292 /* from STCP, retrans queue hinting */
293 struct sk_buff* lost_skb_hint;
295 struct sk_buff *scoreboard_skb_hint;
296 struct sk_buff *retransmit_skb_hint;
297 struct sk_buff *forward_skb_hint;
298 struct sk_buff *fastpath_skb_hint;
300 int fastpath_cnt_hint;
302 int retransmit_cnt_hint;
303 int forward_cnt_hint;
305 __u16 advmss; /* Advertised MSS */
306 __u16 prior_ssthresh; /* ssthresh saved at recovery start */
307 __u32 lost_out; /* Lost packets */
308 __u32 sacked_out; /* SACK'd packets */
309 __u32 fackets_out; /* FACK'd packets */
310 __u32 high_seq; /* snd_nxt at onset of congestion */
312 __u32 retrans_stamp; /* Timestamp of the last retransmit,
313 * also used in SYN-SENT to remember stamp of
315 __u32 undo_marker; /* tracking retrans started here. */
316 int undo_retrans; /* number of undoable retransmissions. */
317 __u32 urg_seq; /* Seq of received urgent pointer */
318 __u16 urg_data; /* Saved octet of OOB data and control flags */
319 __u8 urg_mode; /* In urgent mode */
320 __u8 ecn_flags; /* ECN status bits. */
321 __u32 snd_up; /* Urgent pointer */
323 __u32 total_retrans; /* Total retransmits for entire connection */
324 __u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */
326 unsigned int keepalive_time; /* time before keep alive takes place */
327 unsigned int keepalive_intvl; /* time interval between keep alive probes */
330 unsigned long last_synq_overflow;
332 /* Receiver side RTT estimation */
339 /* Receiver queue space */
346 /* TCP-specific MTU probe information. */
348 __u32 probe_seq_start;
353 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
355 return (struct tcp_sock *)sk;
358 struct tcp_timewait_sock {
359 struct inet_timewait_sock tw_sk;
364 long tw_ts_recent_stamp;
367 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
369 return (struct tcp_timewait_sock *)sk;
374 #endif /* _LINUX_TCP_H */