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1 office 1 /**
2 * @file ipv6_proto.h
3 * @author Ambroz Bizjak <ambrop7@gmail.com>
4 *
5 * @section LICENSE
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the author nor the
15 * names of its contributors may be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
22 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29  
30 #ifndef BADVPN_IPV6_PROTO_H
31 #define BADVPN_IPV6_PROTO_H
32  
33 #include <stdint.h>
34 #include <string.h>
35  
36 #include <misc/debug.h>
37 #include <misc/byteorder.h>
38 #include <misc/packed.h>
39  
40 #define IPV6_NEXT_IGMP 2
41 #define IPV6_NEXT_UDP 17
42  
43 B_START_PACKED
44 struct ipv6_header {
45 uint8_t version4_tc4;
46 uint8_t tc4_fl4;
47 uint16_t fl;
48 uint16_t payload_length;
49 uint8_t next_header;
50 uint8_t hop_limit;
51 uint8_t source_address[16];
52 uint8_t destination_address[16];
53 } B_PACKED;
54 B_END_PACKED
55  
56 static int ipv6_check (uint8_t *data, int data_len, struct ipv6_header *out_header, uint8_t **out_payload, int *out_payload_len)
57 {
58 ASSERT(data_len >= 0)
59 ASSERT(out_header)
60 ASSERT(out_payload)
61 ASSERT(out_payload_len)
62  
63 // check base header
64 if (data_len < sizeof(struct ipv6_header)) {
65 return 0;
66 }
67 memcpy(out_header, data, sizeof(*out_header));
68  
69 // check version
70 if ((ntoh8(out_header->version4_tc4) >> 4) != 6) {
71 return 0;
72 }
73  
74 // check payload length
75 uint16_t payload_length = ntoh16(out_header->payload_length);
76 if (payload_length > data_len - sizeof(struct ipv6_header)) {
77 return 0;
78 }
79  
80 *out_payload = data + sizeof(struct ipv6_header);
81 *out_payload_len = payload_length;
82  
83 return 1;
84 }
85  
86 #endif