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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  */
27 struct 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  */
51 struct 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  */
60 struct 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  */
70 struct 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  */
84 struct dccp_hdr_response {
85 	struct dccp_hdr_ack_bits	dccph_resp_ack;
86 	u_int32_t			dccph_resp_service;
87 };
88 
89 #if 0
90 static 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  */
103 struct 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 
109 enum 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 
123 enum 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