The Tcpdump Group git mirrors - tcpdump/blob - print-erspan.c

   1 /*      $OpenBSD: print-gre.c,v 1.6 2002/10/30 03:04:04 fgsch Exp $     */
   2
   3 /*
   4  * Copyright (c) 2002 Jason L. Wright (jason@thought.net)
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  25  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /* \summary: Cisco ERSPAN printer */
  30
  31 /*
  32  * Specifications: I-D draft-foschiano-erspan-03.
  33  */
  34
  35 #ifdef HAVE_CONFIG_H
  36 #include <config.h>
  37 #endif
  38
  39 #include "netdissect-stdinc.h"
  40
  41 #define ND_LONGJMP_FROM_TCHECK
  42 #include "netdissect.h"
  43 #include "extract.h"
  44
  45 #define ERSPAN2_VER_SHIFT       28
  46 #define ERSPAN2_VER_MASK        (0xfU << ERSPAN2_VER_SHIFT)
  47 #define ERSPAN2_VER             (0x1U << ERSPAN2_VER_SHIFT)
  48 #define ERSPAN2_VLAN_SHIFT      16
  49 #define ERSPAN2_VLAN_MASK       (0xfffU << ERSPAN2_VLAN_SHIFT)
  50 #define ERSPAN2_COS_SHIFT       13
  51 #define ERSPAN2_COS_MASK        (0x7U << ERSPAN2_COS_SHIFT)
  52 #define ERSPAN2_EN_SHIFT        11
  53 #define ERSPAN2_EN_MASK         (0x3U << ERSPAN2_EN_SHIFT)
  54 #define ERSPAN2_EN_NONE         (0x0U << ERSPAN2_EN_SHIFT)
  55 #define ERSPAN2_EN_ISL          (0x1U << ERSPAN2_EN_SHIFT)
  56 #define ERSPAN2_EN_DOT1Q        (0x2U << ERSPAN2_EN_SHIFT)
  57 #define ERSPAN2_EN_VLAN         (0x3U << ERSPAN2_EN_SHIFT)
  58 #define ERSPAN2_T_SHIFT         10
  59 #define ERSPAN2_T_MASK          (0x1U << ERSPAN2_T_SHIFT)
  60 #define ERSPAN2_SID_SHIFT       0
  61 #define ERSPAN2_SID_MASK        (0x3ffU << ERSPAN2_SID_SHIFT)
  62
  63 #define ERSPAN2_INDEX_SHIFT     0
  64 #define ERSPAN2_INDEX_MASK      (0xfffffU << ERSPAN2_INDEX_SHIFT)
  65
  66 /*
  67  * XXX - eh?
  68  */
  69 #define GRE_SP          0x1000          /* sequence# present */
  70
  71 void
  72 erspan_print(netdissect_options *ndo, uint16_t flags, const u_char *bp, u_int len)
  73 {
  74         uint32_t hdr, ver, vlan, cos, en, sid, index;
  75
  76         ndo->ndo_protocol = "erspan";
  77         nd_print_protocol(ndo);
  78
  79         if (!(flags & GRE_SP)) {
  80                 ND_PRINT(" I: ");
  81                 ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
  82                 return;
  83         }
  84
  85         ND_ICHECK_U(len, <, 4);
  86         hdr = GET_BE_U_4(bp);
  87         bp += 4;
  88         len -= 4;
  89
  90         ver = hdr & ERSPAN2_VER_MASK;
  91         if (ver != ERSPAN2_VER) {
  92                 ver >>= ERSPAN2_VER_SHIFT;
  93                 ND_PRINT(" erspan-unknown-version-%x", ver);
  94                 return;
  95         }
  96
  97         if (ndo->ndo_vflag)
  98                 ND_PRINT(" II");
  99
 100         sid = (hdr & ERSPAN2_SID_MASK) >> ERSPAN2_SID_SHIFT;
 101         ND_PRINT(" session %u", sid);
 102
 103         en = hdr & ERSPAN2_EN_MASK;
 104         vlan = (hdr & ERSPAN2_VLAN_MASK) >> ERSPAN2_VLAN_SHIFT;
 105         switch (en) {
 106         case ERSPAN2_EN_NONE:
 107                 break;
 108         case ERSPAN2_EN_ISL:
 109                 ND_PRINT(" isl %u", vlan);
 110                 break;
 111         case ERSPAN2_EN_DOT1Q:
 112                 ND_PRINT(" vlan %u", vlan);
 113                 break;
 114         case ERSPAN2_EN_VLAN:
 115                 ND_PRINT(" vlan payload");
 116                 break;
 117         }
 118
 119         if (ndo->ndo_vflag) {
 120                 cos = (hdr & ERSPAN2_COS_MASK) >> ERSPAN2_COS_SHIFT;
 121                 ND_PRINT(" cos %u", cos);
 122
 123                 if (hdr & ERSPAN2_T_MASK)
 124                         ND_PRINT(" truncated");
 125         }
 126
 127         ND_ICHECK_U(len, <, 4);
 128         hdr = GET_BE_U_4(bp);
 129         bp += 4;
 130         len -= 4;
 131
 132         if (ndo->ndo_vflag) {
 133                 index = (hdr & ERSPAN2_INDEX_MASK) >> ERSPAN2_INDEX_SHIFT;
 134                 ND_PRINT(" index %u", index);
 135         }
 136
 137         ND_PRINT(": ");
 138         ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
 139         return;
 140
 141 invalid:
 142         nd_print_invalid(ndo);
 143 }