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1 /*
2  * Redistribution and use in source and binary forms, with or without
3  * modification, are permitted provided that: (1) source code
4  * distributions retain the above copyright notice and this paragraph
5  * in its entirety, and (2) distributions including binary code include
6  * the above copyright notice and this paragraph in its entirety in
7  * the documentation or other materials provided with the distribution.
8  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
9  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
10  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
11  * FOR A PARTICULAR PURPOSE.
12  *
13  * Original code by Francesco Fondelli (francesco dot fondelli, gmail dot com)
14  */
15 
16 /* \summary: Virtual eXtensible Local Area Network (VXLAN) printer */
17 
18 /* specification: RFC 7348 */
19 
20 #ifdef HAVE_CONFIG_H
21 #include "config.h"
22 #endif
23 
24 #include <netdissect-stdinc.h>
25 
26 #include "netdissect.h"
27 #include "extract.h"
28 
29 static const char tstr[] = " [|VXLAN]";
30 
31 #define VXLAN_HDR_LEN 8
32 
33 /*
34  * VXLAN header, RFC7348
35  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
36  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
37  *
38  *     0                   1                   2                   3
39  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
40  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
41  *    |R|R|R|R|I|R|R|R|            Reserved                           |
42  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
43  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
44  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
45  */
46 
47 void
vxlan_print(netdissect_options * ndo,const u_char * bp,u_int len)48 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
49 {
50     uint8_t flags;
51     uint32_t vni;
52 
53     if (len < VXLAN_HDR_LEN)
54         goto trunc;
55 
56     ND_TCHECK2(*bp, VXLAN_HDR_LEN);
57 
58     flags = *bp;
59     bp += 4;
60 
61     vni = EXTRACT_24BITS(bp);
62     bp += 4;
63 
64     ND_PRINT((ndo, "VXLAN, "));
65     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
66     ND_PRINT((ndo, "vni %u\n", vni));
67 
68     ether_print(ndo, bp, len - VXLAN_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL);
69 
70     return;
71 
72 trunc:
73     ND_PRINT((ndo, "%s", tstr));
74 }
75