tcpdump/print-nsh.c
Guy Harris 3d11d28ba0 Make sure the length of the header is valid.
It must be at least 2, as it includes the lengths of the Base and
Service Path headers, and those are always present.
2016-03-25 12:49:37 -07:00

186 lines
5.3 KiB
C

/* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <netdissect-stdinc.h>
#include "netdissect.h"
#include "extract.h"
static const char tstr[] = " [|NSH]";
static const struct tok nsh_flags [] = {
{ 0x20, "O" },
{ 0x10, "C" },
{ 0, NULL }
};
#define NSH_BASE_HDR_LEN 4
#define NSH_SERVICE_PATH_HDR_LEN 4
#define NSH_HDR_WORD_SIZE 4
/*
* NSH, draft-ietf-sfc-nsh-01 Network Service Header
*/
void
nsh_print(netdissect_options *ndo, const u_char *bp, u_int len)
{
int n, vn;
uint8_t ver;
uint8_t flags;
uint8_t length;
uint8_t md_type;
uint8_t next_protocol;
uint32_t service_path_id;
uint8_t service_index;
uint32_t ctx;
uint16_t tlv_class;
uint8_t tlv_type;
uint8_t tlv_len;
u_int next_len;
/* print Base Header and Service Path Header */
if (len < NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN)
goto trunc;
ND_TCHECK2(*bp, NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN);
ver = (uint8_t)(*bp >> 6);
flags = *bp;
bp += 1;
length = *bp;
bp += 1;
md_type = *bp;
bp += 1;
next_protocol = *bp;
bp += 1;
service_path_id = EXTRACT_24BITS(bp);
bp += 3;
service_index = *bp;
bp += 1;
ND_PRINT((ndo, "NSH, "));
if (ndo->ndo_vflag > 1) {
ND_PRINT((ndo, "ver %d, ", ver));
}
ND_PRINT((ndo, "flags [%s], ", bittok2str_nosep(nsh_flags, "none", flags)));
if (ndo->ndo_vflag > 2) {
ND_PRINT((ndo, "length %d, ", length));
ND_PRINT((ndo, "md type 0x%x, ", md_type));
}
if (ndo->ndo_vflag > 1) {
ND_PRINT((ndo, "next-protocol 0x%x, ", next_protocol));
}
ND_PRINT((ndo, "service-path-id 0x%06x, ", service_path_id));
ND_PRINT((ndo, "service-index 0x%x", service_index));
/* Make sure we have all the headers */
if (len < length * NSH_HDR_WORD_SIZE)
goto trunc;
ND_TCHECK2(*bp, length * NSH_HDR_WORD_SIZE);
/*
* length includes the lengths of the Base and Service Path headers.
* That means it must be at least 2.
*/
if (length < 2)
goto trunc;
/*
* Print, or skip, the Context Headers.
* (length - 2) is the length of those headers.
*/
if (ndo->ndo_vflag > 2) {
if (md_type == 0x01) {
for (n = 0; n < length - 2; n++) {
ctx = EXTRACT_32BITS(bp);
bp += NSH_HDR_WORD_SIZE;
ND_PRINT((ndo, "\n Context[%02d]: 0x%08x", n, ctx));
}
}
else if (md_type == 0x02) {
n = 0;
while (n < length - 2) {
tlv_class = EXTRACT_16BITS(bp);
bp += 2;
tlv_type = *bp;
bp += 1;
tlv_len = *bp;
bp += 1;
ND_PRINT((ndo, "\n TLV Class %d, Type %d, Len %d",
tlv_class, tlv_type, tlv_len));
n += 1;
if (length - 2 < n + tlv_len) {
ND_PRINT((ndo, " ERROR: invalid-tlv-length"));
return;
}
for (vn = 0; vn < tlv_len; vn++) {
ctx = EXTRACT_32BITS(bp);
bp += NSH_HDR_WORD_SIZE;
ND_PRINT((ndo, "\n Value[%02d]: 0x%08x", vn, ctx));
}
n += tlv_len;
}
}
else {
ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
return;
}
}
else {
bp += (length - 2) * NSH_HDR_WORD_SIZE;
}
ND_PRINT((ndo, ndo->ndo_vflag ? "\n " : ": "));
/* print Next Protocol */
next_len = len - length * NSH_HDR_WORD_SIZE;
switch (next_protocol) {
case 0x1:
ip_print(ndo, bp, next_len);
break;
case 0x2:
ip6_print(ndo, bp, next_len);
break;
case 0x3:
ether_print(ndo, bp, next_len, next_len, NULL, NULL);
break;
default:
ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
return;
}
return;
trunc:
ND_PRINT((ndo, "%s", tstr));
}