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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
     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