1/* @(#) $Header: /tcpdump/master/tcpdump/dccp.h,v 1.5 2006-11-02 09:05:23 hannes Exp $ (LBL) */
2/*
3 * Copyright (C) Arnaldo Carvalho de Melo 2004
4 * Copyright (C) Ian McDonald 2005 <iam4@cs.waikato.ac.nz>
5 * Copyright (C) Yoshifumi Nishida 2005
6 *
7 * This software may be distributed either under the terms of the
8 * BSD-style license that accompanies tcpdump or the GNU GPL version 2
9 */
10
11#ifndef __DCCP_HDR__
12#define __DCCP_HDR__
13
14/**
15 * struct dccp_hdr - generic part of DCCP packet header
16 *
17 * @dccph_sport - Relevant port on the endpoint that sent this packet
18 * @dccph_dport - Relevant port on the other endpoint
19 * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
20 * @dccph_ccval - Used by the HC-Sender CCID
21 * @dccph_cscov - Parts of the packet that are covered by the Checksum field
22 * @dccph_checksum - Internet checksum, depends on dccph_cscov
23 * @dccph_x - 0 = 24 bit sequence number, 1 = 48
24 * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
25 * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
26 */
27struct dccp_hdr {
28	u_int16_t	dccph_sport,
29			dccph_dport;
30	u_int8_t	dccph_doff;
31	u_int8_t	dccph_ccval_cscov;
32	u_int16_t	dccph_checksum;
33	union {
34	u_int8_t	dccph_xtr;
35	u_int32_t	dccph_seq;
36	}		dccph_xtrs;
37};
38
39#define DCCPH_CCVAL(dh)	(((dh)->dccph_ccval_cscov >> 4) & 0xF)
40#define DCCPH_CSCOV(dh)	(((dh)->dccph_ccval_cscov) & 0xF)
41
42#define DCCPH_X(dh)	((dh)->dccph_xtrs.dccph_xtr & 1)
43#define DCCPH_TYPE(dh)	(((dh)->dccph_xtrs.dccph_xtr >> 1) & 0xF)
44#define DCCPH_SEQ(dh)   (((dh)->dccph_xtrs.dccph_seq) >> 8)
45
46/**
47 * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
48 *
49 * @dccph_seq_low - low 24 bits of a 48 bit seq packet
50 */
51struct dccp_hdr_ext {
52	u_int32_t	dccph_seq_low;
53};
54
55/**
56 * struct dccp_hdr_request - Conection initiation request header
57 *
58 * @dccph_req_service - Service to which the client app wants to connect
59 */
60struct dccp_hdr_request {
61	u_int32_t	dccph_req_service;
62};
63
64/**
65 * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
66 *
67 * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
68 * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
69 */
70struct dccp_hdr_ack_bits {
71	u_int32_t	dccph_ra;
72	u_int32_t	dccph_ack_nr_low;
73};
74
75#define DCCPH_ACK(dh_ack)   ((dh_ack)->dccph_ra >> 8)
76
77/**
78 * struct dccp_hdr_response - Conection initiation response header
79 *
80 * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
81 * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
82 * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
83 */
84struct dccp_hdr_response {
85	struct dccp_hdr_ack_bits	dccph_resp_ack;
86	u_int32_t			dccph_resp_service;
87};
88
89#if 0
90static inline struct dccp_hdr_data *dccp_hdr_data(struct dccp_hdr *hdrg)
91{
92	const int ext = DCCPH_X(hdrg) ? sizeof(struct dccp_hdr_ext) : 0;
93
94	return (struct dccp_hdr_data *)(((u_char *)hdrg) + sizeof(hdrg) + ext);
95}
96#endif
97
98/**
99 * struct dccp_hdr_reset - Unconditionally shut down a connection
100 *
101 * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
102 */
103struct dccp_hdr_reset {
104	struct dccp_hdr_ack_bits	dccph_reset_ack;
105	u_int8_t			dccph_reset_code,
106					dccph_reset_data[3];
107};
108
109enum dccp_pkt_type {
110	DCCP_PKT_REQUEST = 0,
111	DCCP_PKT_RESPONSE,
112	DCCP_PKT_DATA,
113	DCCP_PKT_ACK,
114	DCCP_PKT_DATAACK,
115	DCCP_PKT_CLOSEREQ,
116	DCCP_PKT_CLOSE,
117	DCCP_PKT_RESET,
118	DCCP_PKT_SYNC,
119	DCCP_PKT_SYNCACK,
120	DCCP_PKT_INVALID
121};
122
123enum dccp_reset_codes {
124	DCCP_RESET_CODE_UNSPECIFIED = 0,
125	DCCP_RESET_CODE_CLOSED,
126	DCCP_RESET_CODE_ABORTED,
127	DCCP_RESET_CODE_NO_CONNECTION,
128	DCCP_RESET_CODE_PACKET_ERROR,
129	DCCP_RESET_CODE_OPTION_ERROR,
130	DCCP_RESET_CODE_MANDATORY_ERROR,
131	DCCP_RESET_CODE_CONNECTION_REFUSED,
132	DCCP_RESET_CODE_BAD_SERVICE_CODE,
133	DCCP_RESET_CODE_TOO_BUSY,
134	DCCP_RESET_CODE_BAD_INIT_COOKIE,
135	DCCP_RESET_CODE_AGGRESSION_PENALTY,
136	__DCCP_RESET_CODE_LAST
137};
138
139#endif /* __DCCP_HDR__ */
140