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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  * OTV header, draft-hasmit-otv-04
     28  *
     29  *     0                   1                   2                   3
     30  *     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
     31  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     32  *     |R|R|R|R|I|R|R|R|           Overlay ID                          |
     33  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     34  *     |          Instance ID                          | Reserved      |
     35  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     36  */
     37 
     38 void
     39 otv_print(netdissect_options *ndo, const u_char *bp, u_int len)
     40 {
     41     uint8_t flags;
     42     uint32_t overlay_id;
     43     uint32_t instance_id;
     44 
     45     if (len < 8) {
     46         ND_PRINT((ndo, "[|OTV]"));
     47         return;
     48     }
     49 
     50     flags = *bp;
     51     bp += 1;
     52 
     53     overlay_id = EXTRACT_24BITS(bp);
     54     bp += 3;
     55 
     56     instance_id = EXTRACT_24BITS(bp);
     57     bp += 4;
     58 
     59     ND_PRINT((ndo, "OTV, "));
     60     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
     61     ND_PRINT((ndo, "overlay %u, ", overlay_id));
     62     ND_PRINT((ndo, "instance %u\n", instance_id));
     63 
     64     ether_print(ndo, bp, len - 8, len - 8, NULL, NULL);
     65 }
     66