suricata
decode-gre.h
Go to the documentation of this file.
1 /* Copyright (C) 2007-2010 Open Information Security Foundation
2  *
3  * You can copy, redistribute or modify this Program under the terms of
4  * the GNU General Public License version 2 as published by the Free
5  * Software Foundation.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * version 2 along with this program; if not, write to the Free Software
14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15  * 02110-1301, USA.
16  */
17 
18 /**
19  * \file decode-gre.h
20  *
21  * \author Breno Silva <breno.silva@gmail.com>
22  *
23  * Generic Route Encapsulation (GRE) from RFC 1701.
24  */
25 
26 #ifndef __DECODE_GRE_H__
27 #define __DECODE_GRE_H__
28 
29 #ifndef IPPROTO_GRE
30 #define IPPROTO_GRE 47
31 #endif
32 
33 #include "decode.h"
34 #include "threadvars.h"
35 
36 typedef struct GREHdr_
37 {
38  uint8_t flags; /**< GRE packet flags */
39  uint8_t version; /**< GRE version */
40  uint16_t ether_type; /**< ether type of the encapsulated traffic */
41 
42 } __attribute__((__packed__)) GREHdr;
43 
44 /* Generic Routing Encapsulation Source Route Entries (SREs).
45  * The header is followed by a variable amount of Routing Information.
46  */
47 typedef struct GRESreHdr_
48 {
49  uint16_t af; /**< Address family */
50  uint8_t sre_offset;
51  uint8_t sre_length;
52 } __attribute__((__packed__)) GRESreHdr;
53 
54 #define GRE_VERSION_0 0x0000
55 #define GRE_VERSION_1 0x0001
56 
57 #define GRE_HDR_LEN 4
58 #define GRE_CHKSUM_LEN 2
59 #define GRE_OFFSET_LEN 2
60 #define GRE_KEY_LEN 4
61 #define GRE_SEQ_LEN 4
62 #define GRE_SRE_HDR_LEN 4
63 #define GRE_PROTO_PPP 0x880b
64 
65 #define GRE_FLAG_ISSET_CHKSUM(r) (r->flags & 0x80)
66 #define GRE_FLAG_ISSET_ROUTE(r) (r->flags & 0x40)
67 #define GRE_FLAG_ISSET_KY(r) (r->flags & 0x20)
68 #define GRE_FLAG_ISSET_SQ(r) (r->flags & 0x10)
69 #define GRE_FLAG_ISSET_SSR(r) (r->flags & 0x08)
70 #define GRE_FLAG_ISSET_RECUR(r) (r->flags & 0x07)
71 #define GRE_GET_VERSION(r) (r->version & 0x07)
72 #define GRE_GET_FLAGS(r) (r->version & 0xF8)
73 #define GRE_GET_PROTO(r) SCNtohs(r->ether_type)
74 
75 #define GREV1_HDR_LEN 8
76 #define GREV1_ACK_LEN 4
77 #define GREV1_FLAG_ISSET_FLAGS(r) (r->version & 0x78)
78 #define GREV1_FLAG_ISSET_ACK(r) (r->version & 0x80)
79 
80 void DecodeGRERegisterTests(void);
81 
82 #endif /* __DECODE_GRE_H__ */
83 
uint8_t sre_length
Definition: decode-gre.h:51
uint16_t af
Definition: decode-gre.h:49
uint8_t version
Definition: decode-gre.h:39
uint16_t ether_type
Definition: decode-gre.h:40
uint8_t sre_offset
Definition: decode-gre.h:50
void DecodeGRERegisterTests(void)
this function registers unit tests for GRE decoder
Definition: decode-gre.c:403
uint8_t flags
Definition: decode-gre.h:38
struct GREHdr_ __attribute__((__packed__)) GREHdr
DNP3 link header.