tcp.h revision 6017:7e310503019e 
1/*
2 * tcp.h
3 *
4 * Transmission Control Protocol (RFC 793).
5 *
6 * Copyright (c) 2000 Dug Song <dugsong@monkey.org>
7 *
8 * $Id: tcp.h,v 1.17 2004/02/23 10:02:11 dugsong Exp $
9 */
10
11#ifndef DNET_TCP_H
12#define DNET_TCP_H
13
14#define TCP_HDR_LEN	20		/* base TCP header length */
15#define TCP_OPT_LEN	2		/* base TCP option length */
16#define TCP_OPT_LEN_MAX	40
17#define TCP_HDR_LEN_MAX	(TCP_HDR_LEN + TCP_OPT_LEN_MAX)
18
19#ifndef __GNUC__
20# define __attribute__(x)
21# pragma pack(1)
22#endif
23
24/*
25 * TCP header, without options
26 */
27struct tcp_hdr {
28        uint16_t	th_sport;	/* source port */
29        uint16_t	th_dport;	/* destination port */
30        uint32_t	th_seq;		/* sequence number */
31        uint32_t	th_ack;		/* acknowledgment number */
32#if DNET_BYTESEX == DNET_BIG_ENDIAN
33        uint8_t		th_off:4,	/* data offset */
34                        th_x2:4;	/* (unused) */
35#elif DNET_BYTESEX == DNET_LIL_ENDIAN
36        uint8_t		th_x2:4,
37                        th_off:4;
38#else
39# error "need to include <dnet.h>"
40#endif
41        uint8_t		th_flags;	/* control flags */
42        uint16_t	th_win;		/* window */
43        uint16_t	th_sum;		/* checksum */
44        uint16_t	th_urp;		/* urgent pointer */
45};
46
47/*
48 * TCP control flags (th_flags)
49 */
50#define TH_FIN		0x01		/* end of data */
51#define TH_SYN		0x02		/* synchronize sequence numbers */
52#define TH_RST		0x04		/* reset connection */
53#define TH_PUSH		0x08		/* push */
54#define TH_ACK		0x10		/* acknowledgment number set */
55#define TH_URG		0x20		/* urgent pointer set */
56#define TH_ECE		0x40		/* ECN echo, RFC 3168 */
57#define TH_CWR		0x80		/* congestion window reduced */
58
59#define TCP_PORT_MAX	65535		/* maximum port */
60#define TCP_WIN_MAX	65535		/* maximum (unscaled) window */
61
62/*
63 * Sequence number comparison macros
64 */
65#define TCP_SEQ_LT(a,b)		((int)((a)-(b)) < 0)
66#define TCP_SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
67#define TCP_SEQ_GT(a,b)		((int)((a)-(b)) > 0)
68#define TCP_SEQ_GEQ(a,b)	((int)((a)-(b)) >= 0)
69
70/*
71 * TCP FSM states
72 */
73#define TCP_STATE_CLOSED	0	/* closed */
74#define TCP_STATE_LISTEN	1	/* listening from connection */
75#define TCP_STATE_SYN_SENT	2	/* active, have sent SYN */
76#define TCP_STATE_SYN_RECEIVED	3	/* have sent and received SYN */
77
78#define TCP_STATE_ESTABLISHED	4	/* established */
79#define TCP_STATE_CLOSE_WAIT	5	/* rcvd FIN, waiting for close */
80
81#define TCP_STATE_FIN_WAIT_1	6	/* have closed, sent FIN */
82#define TCP_STATE_CLOSING	7	/* closed xchd FIN, await FIN-ACK */
83#define TCP_STATE_LAST_ACK	8	/* had FIN and close, await FIN-ACK */
84
85#define TCP_STATE_FIN_WAIT_2	9	/* have closed, FIN is acked */
86#define TCP_STATE_TIME_WAIT	10	/* in 2*MSL quiet wait after close */
87#define TCP_STATE_MAX		11
88
89/*
90 * Options (opt_type) - http://www.iana.org/assignments/tcp-parameters
91 */
92#define TCP_OPT_EOL		0	/* end of option list */
93#define TCP_OPT_NOP		1	/* no operation */
94#define TCP_OPT_MSS		2	/* maximum segment size */
95#define TCP_OPT_WSCALE		3	/* window scale factor, RFC 1072 */
96#define TCP_OPT_SACKOK		4	/* SACK permitted, RFC 2018 */
97#define TCP_OPT_SACK		5	/* SACK, RFC 2018 */
98#define TCP_OPT_ECHO		6	/* echo (obsolete), RFC 1072 */
99#define TCP_OPT_ECHOREPLY	7	/* echo reply (obsolete), RFC 1072 */
100#define TCP_OPT_TIMESTAMP	8	/* timestamp, RFC 1323 */
101#define TCP_OPT_POCONN		9	/* partial order conn, RFC 1693 */
102#define TCP_OPT_POSVC		10	/* partial order service, RFC 1693 */
103#define TCP_OPT_CC		11	/* connection count, RFC 1644 */
104#define TCP_OPT_CCNEW		12	/* CC.NEW, RFC 1644 */
105#define TCP_OPT_CCECHO		13	/* CC.ECHO, RFC 1644 */
106#define TCP_OPT_ALTSUM		14	/* alt checksum request, RFC 1146 */
107#define TCP_OPT_ALTSUMDATA	15	/* alt checksum data, RFC 1146 */
108#define TCP_OPT_SKEETER		16	/* Skeeter */
109#define TCP_OPT_BUBBA		17	/* Bubba */
110#define TCP_OPT_TRAILSUM	18	/* trailer checksum */
111#define TCP_OPT_MD5		19	/* MD5 signature, RFC 2385 */
112#define TCP_OPT_SCPS		20	/* SCPS capabilities */
113#define TCP_OPT_SNACK		21	/* selective negative acks */
114#define TCP_OPT_REC		22	/* record boundaries */
115#define TCP_OPT_CORRUPT		23	/* corruption experienced */
116#define TCP_OPT_SNAP		24	/* SNAP */
117#define TCP_OPT_TCPCOMP		26	/* TCP compression filter */
118#define TCP_OPT_MAX		27
119
120#define TCP_OPT_TYPEONLY(type)	\
121        ((type) == TCP_OPT_EOL || (type) == TCP_OPT_NOP)
122
123/*
124 * TCP option (following TCP header)
125 */
126struct tcp_opt {
127        uint8_t		opt_type;	/* option type */
128        uint8_t		opt_len;	/* option length >= TCP_OPT_LEN */
129        union tcp_opt_data {
130                uint16_t	mss;		/* TCP_OPT_MSS */
131                uint8_t		wscale;		/* TCP_OPT_WSCALE */
132                uint16_t	sack[19];	/* TCP_OPT_SACK */
133                uint32_t	echo;		/* TCP_OPT_ECHO{REPLY} */
134                uint32_t	timestamp[2];	/* TCP_OPT_TIMESTAMP */
135                uint32_t	cc;		/* TCP_OPT_CC{NEW,ECHO} */
136                uint8_t		cksum;		/* TCP_OPT_ALTSUM */
137                uint8_t		md5[16];	/* TCP_OPT_MD5 */
138                uint8_t		data8[TCP_OPT_LEN_MAX - TCP_OPT_LEN];
139        } opt_data;
140} __attribute__((__packed__));
141
142#ifndef __GNUC__
143# pragma pack()
144#endif
145
146#define tcp_pack_hdr(hdr, sport, dport, seq, ack, flags, win, urp) do {	\
147        struct tcp_hdr *tcp_pack_p = (struct tcp_hdr *)(hdr);		\
148        tcp_pack_p->th_sport = htons(sport);				\
149        tcp_pack_p->th_dport = htons(dport);				\
150        tcp_pack_p->th_seq = htonl(seq);				\
151        tcp_pack_p->th_ack = htonl(ack);				\
152        tcp_pack_p->th_x2 = 0; tcp_pack_p->th_off = 5;			\
153        tcp_pack_p->th_flags = flags;					\
154        tcp_pack_p->th_win = htons(win);				\
155        tcp_pack_p->th_urp = htons(urp);				\
156} while (0)
157
158#endif /* DNET_TCP_H */
159