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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 #define NETDISSECT_REWORKED
     17 #ifdef HAVE_CONFIG_H
     18 #include "config.h"
     19 #endif
     20 
     21 #include <tcpdump-stdinc.h>
     22 
     23 #include "interface.h"
     24 #include "extract.h"
     25 
     26 /*
     27  * VXLAN header, RFC7348
     28  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
     29  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
     30  *
     31  *     0                   1                   2                   3
     32  *     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
     33  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     34  *    |R|R|R|R|I|R|R|R|            Reserved                           |
     35  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     36  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
     37  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     38  */
     39 
     40 void
     41 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
     42 {
     43     uint8_t flags;
     44     uint32_t vni;
     45 
     46     if (len < 8) {
     47         ND_PRINT((ndo, "[|VXLAN]"));
     48         return;
     49     }
     50 
     51     flags = *bp;
     52     bp += 4;
     53 
     54     vni = EXTRACT_24BITS(bp);
     55     bp += 4;
     56 
     57     ND_PRINT((ndo, "VXLAN, "));
     58     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
     59     ND_PRINT((ndo, "vni %u\n", vni));
     60 
     61     ether_print(ndo, bp, len - 8, len - 8, NULL, NULL);
     62 }
     63