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 <linux/dmaengine.h>
22 #include <asm/byteorder.h>
29 #if defined(__LITTLE_ENDIAN_BITFIELD)
40 #elif defined(__BIG_ENDIAN_BITFIELD)
52 #error "Adjust your <asm/byteorder.h> defines"
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.
69 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
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)
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 */
99 #define TCPI_OPT_TIMESTAMPS 1
100 #define TCPI_OPT_SACK 2
101 #define TCPI_OPT_WSCALE 4
102 #define TCPI_OPT_ECN 8
107 #define TCPF_CA_Open (1<<TCP_CA_Open)
109 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
111 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
113 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
115 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
122 __u8 tcpi_retransmits;
126 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
140 __u32 tcpi_last_data_sent;
141 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
142 __u32 tcpi_last_data_recv;
143 __u32 tcpi_last_ack_recv;
147 __u32 tcpi_rcv_ssthresh;
150 __u32 tcpi_snd_ssthresh;
153 __u32 tcpi_reordering;
156 __u32 tcpi_rcv_space;
158 __u32 tcpi_total_retrans;
163 #include <linux/config.h>
164 #include <linux/skbuff.h>
165 #include <net/sock.h>
166 #include <net/inet_connection_sock.h>
167 #include <net/inet_timewait_sock.h>
169 /* This defines a selective acknowledgement block. */
170 struct tcp_sack_block {
175 struct tcp_options_received {
177 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
178 __u32 ts_recent; /* Time stamp to echo next */
179 __u32 rcv_tsval; /* Time stamp value */
180 __u32 rcv_tsecr; /* Time stamp echo reply */
181 __u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */
182 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */
183 dsack : 1, /* D-SACK is scheduled */
184 wscale_ok : 1, /* Wscale seen on SYN packet */
185 sack_ok : 4, /* SACK seen on SYN packet */
186 snd_wscale : 4, /* Window scaling received from sender */
187 rcv_wscale : 4; /* Window scaling to send to receiver */
189 __u8 eff_sacks; /* Size of SACK array to send with next packet */
190 __u8 num_sacks; /* Number of SACK blocks */
191 __u16 user_mss; /* mss requested by user in ioctl */
192 __u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
195 struct tcp_request_sock {
196 struct inet_request_sock req;
201 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
203 return (struct tcp_request_sock *)req;
207 /* inet_connection_sock has to be the first member of tcp_sock */
208 struct inet_connection_sock inet_conn;
209 int tcp_header_len; /* Bytes of tcp header to send */
212 * Header prediction flags
213 * 0x5?10 << 16 + snd_wnd in net byte order
218 * RFC793 variables by their proper names. This means you can
219 * read the code and the spec side by side (and laugh ...)
220 * See RFC793 and RFC1122. The RFC writes these in capitals.
222 __u32 rcv_nxt; /* What we want to receive next */
223 __u32 snd_nxt; /* Next sequence we send */
225 __u32 snd_una; /* First byte we want an ack for */
226 __u32 snd_sml; /* Last byte of the most recently transmitted small packet */
227 __u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
228 __u32 lsndtime; /* timestamp of last sent data packet (for restart window) */
230 /* Data for direct copy to user */
232 struct sk_buff_head prequeue;
233 struct task_struct *task;
237 #ifdef CONFIG_NET_DMA
238 /* members for async copy */
239 struct dma_chan *dma_chan;
241 struct dma_pinned_list *pinned_list;
242 dma_cookie_t dma_cookie;
246 __u32 snd_wl1; /* Sequence for window update */
247 __u32 snd_wnd; /* The window we expect to receive */
248 __u32 max_window; /* Maximal window ever seen from peer */
249 __u32 mss_cache; /* Cached effective mss, not including SACKS */
250 __u16 xmit_size_goal; /* Goal for segmenting output packets */
251 /* XXX Two bytes hole, try to pack */
253 __u32 window_clamp; /* Maximal window to advertise */
254 __u32 rcv_ssthresh; /* Current window clamp */
256 __u32 frto_highmark; /* snd_nxt when RTO occurred */
257 __u8 reordering; /* Packet reordering metric. */
258 __u8 frto_counter; /* Number of new acks after RTO */
259 __u8 nonagle; /* Disable Nagle algorithm? */
260 __u8 keepalive_probes; /* num of allowed keep alive probes */
262 /* RTT measurement */
263 __u32 srtt; /* smoothed round trip time << 3 */
264 __u32 mdev; /* medium deviation */
265 __u32 mdev_max; /* maximal mdev for the last rtt period */
266 __u32 rttvar; /* smoothed mdev_max */
267 __u32 rtt_seq; /* sequence number to update rttvar */
269 __u32 packets_out; /* Packets which are "in flight" */
270 __u32 left_out; /* Packets which leaved network */
271 __u32 retrans_out; /* Retransmitted packets out */
273 * Options received (usually on last packet, some only on SYN packets).
275 struct tcp_options_received rx_opt;
278 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
280 __u32 snd_ssthresh; /* Slow start size threshold */
281 __u32 snd_cwnd; /* Sending congestion window */
282 __u16 snd_cwnd_cnt; /* Linear increase counter */
283 __u16 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
285 __u32 snd_cwnd_stamp;
287 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */
289 __u32 rcv_wnd; /* Current receiver window */
290 __u32 rcv_wup; /* rcv_nxt on last window update sent */
291 __u32 write_seq; /* Tail(+1) of data held in tcp send buffer */
292 __u32 pushed_seq; /* Last pushed seq, required to talk to windows */
293 __u32 copied_seq; /* Head of yet unread data */
296 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
297 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
299 struct tcp_sack_block recv_sack_cache[4];
301 /* from STCP, retrans queue hinting */
302 struct sk_buff* lost_skb_hint;
304 struct sk_buff *scoreboard_skb_hint;
305 struct sk_buff *retransmit_skb_hint;
306 struct sk_buff *forward_skb_hint;
307 struct sk_buff *fastpath_skb_hint;
309 int fastpath_cnt_hint;
311 int retransmit_cnt_hint;
312 int forward_cnt_hint;
314 __u16 advmss; /* Advertised MSS */
315 __u16 prior_ssthresh; /* ssthresh saved at recovery start */
316 __u32 lost_out; /* Lost packets */
317 __u32 sacked_out; /* SACK'd packets */
318 __u32 fackets_out; /* FACK'd packets */
319 __u32 high_seq; /* snd_nxt at onset of congestion */
321 __u32 retrans_stamp; /* Timestamp of the last retransmit,
322 * also used in SYN-SENT to remember stamp of
324 __u32 undo_marker; /* tracking retrans started here. */
325 int undo_retrans; /* number of undoable retransmissions. */
326 __u32 urg_seq; /* Seq of received urgent pointer */
327 __u16 urg_data; /* Saved octet of OOB data and control flags */
328 __u8 urg_mode; /* In urgent mode */
329 __u8 ecn_flags; /* ECN status bits. */
330 __u32 snd_up; /* Urgent pointer */
332 __u32 total_retrans; /* Total retransmits for entire connection */
333 __u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */
335 unsigned int keepalive_time; /* time before keep alive takes place */
336 unsigned int keepalive_intvl; /* time interval between keep alive probes */
339 unsigned long last_synq_overflow;
341 /* Receiver side RTT estimation */
348 /* Receiver queue space */
355 /* TCP-specific MTU probe information. */
357 __u32 probe_seq_start;
362 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
364 return (struct tcp_sock *)sk;
367 struct tcp_timewait_sock {
368 struct inet_timewait_sock tw_sk;
373 long tw_ts_recent_stamp;
376 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
378 return (struct tcp_timewait_sock *)sk;
383 #endif /* _LINUX_TCP_H */