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>
22 #include <linux/socket.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
= __cpu_to_be32(0x00800000),
73 TCP_FLAG_ECE
= __cpu_to_be32(0x00400000),
74 TCP_FLAG_URG
= __cpu_to_be32(0x00200000),
75 TCP_FLAG_ACK
= __cpu_to_be32(0x00100000),
76 TCP_FLAG_PSH
= __cpu_to_be32(0x00080000),
77 TCP_FLAG_RST
= __cpu_to_be32(0x00040000),
78 TCP_FLAG_SYN
= __cpu_to_be32(0x00020000),
79 TCP_FLAG_FIN
= __cpu_to_be32(0x00010000),
80 TCP_RESERVED_BITS
= __cpu_to_be32(0x0F000000),
81 TCP_DATA_OFFSET
= __cpu_to_be32(0xF0000000)
85 * TCP general constants
87 #define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */
88 #define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */
90 /* TCP socket options */
91 #define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
92 #define TCP_MAXSEG 2 /* Limit MSS */
93 #define TCP_CORK 3 /* Never send partially complete segments */
94 #define TCP_KEEPIDLE 4 /* Start keeplives after this period */
95 #define TCP_KEEPINTVL 5 /* Interval between keepalives */
96 #define TCP_KEEPCNT 6 /* Number of keepalives before death */
97 #define TCP_SYNCNT 7 /* Number of SYN retransmits */
98 #define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
99 #define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
100 #define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
101 #define TCP_INFO 11 /* Information about this connection. */
102 #define TCP_QUICKACK 12 /* Block/reenable quick acks */
103 #define TCP_CONGESTION 13 /* Congestion control algorithm */
104 #define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */
105 #define TCP_COOKIE_TRANSACTIONS 15 /* TCP Cookie Transactions */
107 /* for TCP_INFO socket option */
108 #define TCPI_OPT_TIMESTAMPS 1
109 #define TCPI_OPT_SACK 2
110 #define TCPI_OPT_WSCALE 4
111 #define TCPI_OPT_ECN 8
115 #define TCPF_CA_Open (1<<TCP_CA_Open)
117 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
119 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
121 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
123 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
129 __u8 tcpi_retransmits
;
133 __u8 tcpi_snd_wscale
: 4, tcpi_rcv_wscale
: 4;
147 __u32 tcpi_last_data_sent
;
148 __u32 tcpi_last_ack_sent
; /* Not remembered, sorry. */
149 __u32 tcpi_last_data_recv
;
150 __u32 tcpi_last_ack_recv
;
154 __u32 tcpi_rcv_ssthresh
;
157 __u32 tcpi_snd_ssthresh
;
160 __u32 tcpi_reordering
;
163 __u32 tcpi_rcv_space
;
165 __u32 tcpi_total_retrans
;
168 /* for TCP_MD5SIG socket option */
169 #define TCP_MD5SIG_MAXKEYLEN 80
172 struct __kernel_sockaddr_storage tcpm_addr
; /* address associated */
173 __u16 __tcpm_pad1
; /* zero */
174 __u16 tcpm_keylen
; /* key length */
175 __u32 __tcpm_pad2
; /* zero */
176 __u8 tcpm_key
[TCP_MD5SIG_MAXKEYLEN
]; /* key (binary) */
179 /* for TCP_COOKIE_TRANSACTIONS (TCPCT) socket option */
180 #define TCP_COOKIE_MIN 8 /* 64-bits */
181 #define TCP_COOKIE_MAX 16 /* 128-bits */
182 #define TCP_COOKIE_PAIR_SIZE (2*TCP_COOKIE_MAX)
184 /* Flags for both getsockopt and setsockopt */
185 #define TCP_COOKIE_IN_ALWAYS (1 << 0) /* Discard SYN without cookie */
186 #define TCP_COOKIE_OUT_NEVER (1 << 1) /* Prohibit outgoing cookies,
187 * supercedes everything. */
189 /* Flags for getsockopt */
190 #define TCP_S_DATA_IN (1 << 2) /* Was data received? */
191 #define TCP_S_DATA_OUT (1 << 3) /* Was data sent? */
193 /* TCP_COOKIE_TRANSACTIONS data */
194 struct tcp_cookie_transactions
{
195 __u16 tcpct_flags
; /* see above */
196 __u8 __tcpct_pad1
; /* zero */
197 __u8 tcpct_cookie_desired
; /* bytes */
198 __u16 tcpct_s_data_desired
; /* bytes of variable data */
199 __u16 tcpct_used
; /* bytes in value */
200 __u8 tcpct_value
[TCP_MSS_DEFAULT
];
205 #include <linux/skbuff.h>
206 #include <linux/dmaengine.h>
207 #include <net/sock.h>
208 #include <net/inet_connection_sock.h>
209 #include <net/inet_timewait_sock.h>
211 static inline struct tcphdr
*tcp_hdr(const struct sk_buff
*skb
)
213 return (struct tcphdr
*)skb_transport_header(skb
);
216 static inline unsigned int tcp_hdrlen(const struct sk_buff
*skb
)
218 return tcp_hdr(skb
)->doff
* 4;
221 static inline unsigned int tcp_optlen(const struct sk_buff
*skb
)
223 return (tcp_hdr(skb
)->doff
- 5) * 4;
226 /* This defines a selective acknowledgement block. */
227 struct tcp_sack_block_wire
{
232 struct tcp_sack_block
{
237 struct tcp_options_received
{
239 long ts_recent_stamp
;/* Time we stored ts_recent (for aging) */
240 u32 ts_recent
; /* Time stamp to echo next */
241 u32 rcv_tsval
; /* Time stamp value */
242 u32 rcv_tsecr
; /* Time stamp echo reply */
243 u16 saw_tstamp
: 1, /* Saw TIMESTAMP on last packet */
244 tstamp_ok
: 1, /* TIMESTAMP seen on SYN packet */
245 dsack
: 1, /* D-SACK is scheduled */
246 wscale_ok
: 1, /* Wscale seen on SYN packet */
247 sack_ok
: 4, /* SACK seen on SYN packet */
248 snd_wscale
: 4, /* Window scaling received from sender */
249 rcv_wscale
: 4; /* Window scaling to send to receiver */
251 u8 num_sacks
; /* Number of SACK blocks */
252 u16 user_mss
; /* mss requested by user in ioctl */
253 u16 mss_clamp
; /* Maximal mss, negotiated at connection setup */
256 static inline void tcp_clear_options(struct tcp_options_received
*rx_opt
)
258 rx_opt
->tstamp_ok
= rx_opt
->sack_ok
= rx_opt
->wscale_ok
= rx_opt
->snd_wscale
= 0;
261 /* This is the max number of SACKS that we'll generate and process. It's safe
262 * to increse this, although since:
263 * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
264 * only four options will fit in a standard TCP header */
265 #define TCP_NUM_SACKS 4
267 struct tcp_request_sock
{
268 struct inet_request_sock req
;
269 #ifdef CONFIG_TCP_MD5SIG
270 /* Only used by TCP MD5 Signature so far. */
271 const struct tcp_request_sock_ops
*af_specific
;
277 static inline struct tcp_request_sock
*tcp_rsk(const struct request_sock
*req
)
279 return (struct tcp_request_sock
*)req
;
283 /* inet_connection_sock has to be the first member of tcp_sock */
284 struct inet_connection_sock inet_conn
;
285 u16 tcp_header_len
; /* Bytes of tcp header to send */
286 u16 xmit_size_goal_segs
; /* Goal for segmenting output packets */
289 * Header prediction flags
290 * 0x5?10 << 16 + snd_wnd in net byte order
295 * RFC793 variables by their proper names. This means you can
296 * read the code and the spec side by side (and laugh ...)
297 * See RFC793 and RFC1122. The RFC writes these in capitals.
299 u32 rcv_nxt
; /* What we want to receive next */
300 u32 copied_seq
; /* Head of yet unread data */
301 u32 rcv_wup
; /* rcv_nxt on last window update sent */
302 u32 snd_nxt
; /* Next sequence we send */
304 u32 snd_una
; /* First byte we want an ack for */
305 u32 snd_sml
; /* Last byte of the most recently transmitted small packet */
306 u32 rcv_tstamp
; /* timestamp of last received ACK (for keepalives) */
307 u32 lsndtime
; /* timestamp of last sent data packet (for restart window) */
309 /* Data for direct copy to user */
311 struct sk_buff_head prequeue
;
312 struct task_struct
*task
;
316 #ifdef CONFIG_NET_DMA
317 /* members for async copy */
318 struct dma_chan
*dma_chan
;
320 struct dma_pinned_list
*pinned_list
;
321 dma_cookie_t dma_cookie
;
325 u32 snd_wl1
; /* Sequence for window update */
326 u32 snd_wnd
; /* The window we expect to receive */
327 u32 max_window
; /* Maximal window ever seen from peer */
328 u32 mss_cache
; /* Cached effective mss, not including SACKS */
330 u32 window_clamp
; /* Maximal window to advertise */
331 u32 rcv_ssthresh
; /* Current window clamp */
333 u32 frto_highmark
; /* snd_nxt when RTO occurred */
334 u16 advmss
; /* Advertised MSS */
335 u8 frto_counter
; /* Number of new acks after RTO */
336 u8 nonagle
; /* Disable Nagle algorithm? */
338 /* RTT measurement */
339 u32 srtt
; /* smoothed round trip time << 3 */
340 u32 mdev
; /* medium deviation */
341 u32 mdev_max
; /* maximal mdev for the last rtt period */
342 u32 rttvar
; /* smoothed mdev_max */
343 u32 rtt_seq
; /* sequence number to update rttvar */
345 u32 packets_out
; /* Packets which are "in flight" */
346 u32 retrans_out
; /* Retransmitted packets out */
348 u16 urg_data
; /* Saved octet of OOB data and control flags */
349 u8 ecn_flags
; /* ECN status bits. */
350 u8 reordering
; /* Packet reordering metric. */
351 u32 snd_up
; /* Urgent pointer */
353 u8 keepalive_probes
; /* num of allowed keep alive probes */
355 * Options received (usually on last packet, some only on SYN packets).
357 struct tcp_options_received rx_opt
;
360 * Slow start and congestion control (see also Nagle, and Karn & Partridge)
362 u32 snd_ssthresh
; /* Slow start size threshold */
363 u32 snd_cwnd
; /* Sending congestion window */
364 u32 snd_cwnd_cnt
; /* Linear increase counter */
365 u32 snd_cwnd_clamp
; /* Do not allow snd_cwnd to grow above this */
369 u32 rcv_wnd
; /* Current receiver window */
370 u32 write_seq
; /* Tail(+1) of data held in tcp send buffer */
371 u32 pushed_seq
; /* Last pushed seq, required to talk to windows */
372 u32 lost_out
; /* Lost packets */
373 u32 sacked_out
; /* SACK'd packets */
374 u32 fackets_out
; /* FACK'd packets */
376 u32 bytes_acked
; /* Appropriate Byte Counting - RFC3465 */
378 /* from STCP, retrans queue hinting */
379 struct sk_buff
* lost_skb_hint
;
380 struct sk_buff
*scoreboard_skb_hint
;
381 struct sk_buff
*retransmit_skb_hint
;
383 struct sk_buff_head out_of_order_queue
; /* Out of order segments go here */
385 /* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */
386 struct tcp_sack_block duplicate_sack
[1]; /* D-SACK block */
387 struct tcp_sack_block selective_acks
[4]; /* The SACKS themselves*/
389 struct tcp_sack_block recv_sack_cache
[4];
391 struct sk_buff
*highest_sack
; /* highest skb with SACK received
392 * (validity guaranteed only if
397 u32 retransmit_high
; /* L-bits may be on up to this seqno */
399 u32 lost_retrans_low
; /* Sent seq after any rxmit (lowest) */
401 u32 prior_ssthresh
; /* ssthresh saved at recovery start */
402 u32 high_seq
; /* snd_nxt at onset of congestion */
404 u32 retrans_stamp
; /* Timestamp of the last retransmit,
405 * also used in SYN-SENT to remember stamp of
407 u32 undo_marker
; /* tracking retrans started here. */
408 int undo_retrans
; /* number of undoable retransmissions. */
409 u32 total_retrans
; /* Total retransmits for entire connection */
411 u32 urg_seq
; /* Seq of received urgent pointer */
412 unsigned int keepalive_time
; /* time before keep alive takes place */
413 unsigned int keepalive_intvl
; /* time interval between keep alive probes */
417 /* Receiver side RTT estimation */
424 /* Receiver queue space */
431 /* TCP-specific MTU probe information. */
437 #ifdef CONFIG_TCP_MD5SIG
438 /* TCP AF-Specific parts; only used by MD5 Signature support so far */
439 const struct tcp_sock_af_ops
*af_specific
;
441 /* TCP MD5 Signature Option information */
442 struct tcp_md5sig_info
*md5sig_info
;
446 static inline struct tcp_sock
*tcp_sk(const struct sock
*sk
)
448 return (struct tcp_sock
*)sk
;
451 struct tcp_timewait_sock
{
452 struct inet_timewait_sock tw_sk
;
457 long tw_ts_recent_stamp
;
458 #ifdef CONFIG_TCP_MD5SIG
460 u8 tw_md5_key
[TCP_MD5SIG_MAXKEYLEN
];
464 static inline struct tcp_timewait_sock
*tcp_twsk(const struct sock
*sk
)
466 return (struct tcp_timewait_sock
*)sk
;
469 #endif /* __KERNEL__ */
471 #endif /* _LINUX_TCP_H */