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/* Copyright (c) 2015, bugyo
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* \summary: Generic Protocol Extension for VXLAN (VXLAN GPE) printer */
/* specification: draft-ietf-nvo3-vxlan-gpe-12 */
#include <config.h>
#include "netdissect-stdinc.h"
#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "extract.h"
#define VXLAN_GPE_VER 0x30 /* GPE */
#define VXLAN_GPE_SHIFT 4
#define VXLAN_GPE_VER_0 0x0
#define VXLAN_GPE_I 0x08 /* Instance Bit */
#define VXLAN_GPE_P 0x04 /* GPE Next Protocol */
#define VXLAN_GPE_B 0x02 /* GPE BUM Traffic */
#define VXLAN_GPE_O 0x01 /* GPE OAM Flag */
static const struct tok vxlan_gpe_flags [] = {
{ VXLAN_GPE_I, "I" },
{ VXLAN_GPE_P, "P" },
{ VXLAN_GPE_B, "B" },
{ VXLAN_GPE_O, "O" },
{ 0, NULL }
};
#define VXLAN_GPE_PROTO_RESERVED 0x00
#define VXLAN_GPE_PROTO_IPV4 0x01
#define VXLAN_GPE_PROTO_IPV6 0x02
#define VXLAN_GPE_PROTO_ETHERNET 0x03
#define VXLAN_GPE_PROTO_NSH 0x04
#define VXLAN_GPE_HDR_LEN 8
/*
* VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-12
* Generic Protocol Extension for VXLAN
*
* 0 1 2 3
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |R|R|Ver|I|P|B|O| Reserved |Next Protocol |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | VXLAN Network Identifier (VNI) | Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
void
vxlan_gpe_print(netdissect_options *ndo, const u_char *bp, u_int len)
{
uint8_t flags, ver;
uint8_t next_protocol;
/*
* XXX - OpenBSD has a single dissector for VXLAN and VXLAN-GPE,
* using the flag bits to distinguish between them.
*
* draft-ietf-nvo3-vxlan-gpe-12, the final VXLAN-GPE draft, says
* that VXLAN-GPE uses port 4790, rather than VXLAN's port 4789,
* and that the P flag bit must be set for VXLAN-GPE packets,
* indicating that the header includes a "next protocol" field,
* and that if a packet with the P it not set is received on
* port 4790, "the "Next Protocol" field must be set to zero and
* the payload MUST be ETHERNET(L2) as defined by [RFC7348]."
*/
ndo->ndo_protocol = "vxlan_gpe";
ND_PRINT("VXLAN-GPE, ");
if (len < VXLAN_GPE_HDR_LEN) {
ND_PRINT(" (len %u < %u)", len, VXLAN_GPE_HDR_LEN);
goto invalid;
}
flags = GET_U_1(bp);
bp += 1;
len -= 1;
ver = (flags & VXLAN_GPE_VER) >> VXLAN_GPE_SHIFT;
if (ver != VXLAN_GPE_VER_0) {
ND_PRINT("unknown version %u", ver);
goto invalid;
}
ND_PRINT("flags [%s], ",
bittok2str_nosep(vxlan_gpe_flags, "none", flags));
/* Reserved */
bp += 2;
len -= 2;
/*
* If the VXLAN_GPE_P flag bit isn't set, that means this is a VXLAN
* packet, not a VXLAN-GPE packet, and thus has no "next protocol"
* field; the payload is Ethernet.
*/
if (flags & VXLAN_GPE_P)
next_protocol = GET_U_1(bp);
else
next_protocol = VXLAN_GPE_PROTO_ETHERNET;
bp += 1;
len -= 1;
/*
* Both RFC 7348 and draft-ietf-nvo3-vxlan-gpe-12 say that the I flag
* MUST be set.
*/
if (flags & VXLAN_GPE_I)
ND_PRINT("vni %u", GET_BE_U_3(bp));
else
ND_PRINT("ERROR: I flag not set");
bp += 3;
len -= 3;
if (flags & VXLAN_GPE_B)
ND_PRINT(", BUM");
if (flags & VXLAN_GPE_O) {
ND_PRINT(", OAM (proto 0x%x, len %u)", next_protocol, len);
return;
}
/* Reserved */
ND_TCHECK_1(bp);
bp += 1;
len -= 1;
ND_PRINT(ndo->ndo_vflag ? "\n " : ": ");
switch (next_protocol) {
case VXLAN_GPE_PROTO_IPV4:
ip_print(ndo, bp, len);
break;
case VXLAN_GPE_PROTO_IPV6:
ip6_print(ndo, bp, len);
break;
case VXLAN_GPE_PROTO_ETHERNET:
ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
break;
case VXLAN_GPE_PROTO_NSH:
nsh_print(ndo, bp, len);
break;
/*
* OpenBSD supports 0x05 for MPLS, which was in earlier drafts
* of VXLAN GPE, but not in the final -12 draft.
*/
default:
ND_PRINT("ERROR: unknown-next-protocol");
goto invalid;
}
return;
invalid:
nd_print_invalid(ndo);
}
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