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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 #include <sys/cdefs.h>
     17 #ifndef lint
     18 __RCSID("$NetBSD: print-vxlan.c,v 1.5 2024/09/02 16:15:33 christos Exp $");
     19 #endif
     20 
     21 /* \summary: Virtual eXtensible Local Area Network (VXLAN) printer */
     22 
     23 /* specification: RFC 7348 */
     24 
     25 #include <config.h>
     26 
     27 #include "netdissect-stdinc.h"
     28 
     29 #define ND_LONGJMP_FROM_TCHECK
     30 #include "netdissect.h"
     31 #include "extract.h"
     32 
     33 static const struct tok vxlan_flags [] = {
     34     { 0x08, "I" },
     35     { 0, NULL }
     36 };
     37 #define VXLAN_HDR_LEN 8
     38 
     39 /*
     40  * VXLAN header, RFC7348
     41  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
     42  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
     43  *
     44  *     0                   1                   2                   3
     45  *     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
     46  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     47  *    |R|R|R|R|I|R|R|R|            Reserved                           |
     48  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     49  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
     50  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     51  */
     52 
     53 void
     54 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
     55 {
     56     uint8_t flags;
     57     uint32_t vni;
     58 
     59     ndo->ndo_protocol = "vxlan";
     60     nd_print_protocol_caps(ndo);
     61     if (len < VXLAN_HDR_LEN)
     62         goto invalid;
     63 
     64     flags = GET_U_1(bp);
     65     bp += 1;
     66     ND_PRINT(", flags [%s] (0x%02x), ",
     67              bittok2str_nosep(vxlan_flags, "invalid", flags), flags);
     68 
     69     /* 1st Reserved */
     70     bp += 3;
     71 
     72     vni = GET_BE_U_3(bp);
     73     bp += 3;
     74     ND_PRINT("vni %u\n", vni);
     75 
     76     /* 2nd Reserved */
     77     ND_TCHECK_1(bp);
     78     bp += 1;
     79 
     80     ether_print(ndo, bp, len - VXLAN_HDR_LEN, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
     81 
     82     return;
     83 
     84 invalid:
     85     nd_print_invalid(ndo);
     86 }
     87