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918a034032
tcpdump/print-babel.c
Matthieu Boutier 918a034032 Babel: add decoder for source-specific extension.
2015-08-13 21:25:38 +01:00

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/*
* Copyright (c) 2007-2011 Grégoire Henry, Juliusz Chroboczek
*
* 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.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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 <tcpdump-stdinc.h>
#include <stdio.h>
#include <string.h>
#include "interface.h"
#include "addrtoname.h"
#include "extract.h"
static const char tstr[] = "[|babel]";
static void babel_print_v2(netdissect_options *, const u_char *cp, u_int length);
void
babel_print(netdissect_options *ndo,
const u_char *cp, u_int length)
{
ND_PRINT((ndo, "babel"));
ND_TCHECK2(*cp, 4);
if(cp[0] != 42) {
ND_PRINT((ndo, " malformed header"));
return;
} else {
ND_PRINT((ndo, " %d", cp[1]));
}
switch(cp[1]) {
case 2:
babel_print_v2(ndo, cp, length);
break;
default:
ND_PRINT((ndo, " unknown version"));
break;
}
return;
trunc:
ND_PRINT((ndo, " %s", tstr));
return;
}
/* TLVs */
#define MESSAGE_PAD1 0
#define MESSAGE_PADN 1
#define MESSAGE_ACK_REQ 2
#define MESSAGE_ACK 3
#define MESSAGE_HELLO 4
#define MESSAGE_IHU 5
#define MESSAGE_ROUTER_ID 6
#define MESSAGE_NH 7
#define MESSAGE_UPDATE 8
#define MESSAGE_REQUEST 9
#define MESSAGE_MH_REQUEST 10
#define MESSAGE_TSPC 11
#define MESSAGE_HMAC 12
#define MESSAGE_UPDATE_SRC_SPECIFIC 13
#define MESSAGE_REQUEST_SRC_SPECIFIC 14
#define MESSAGE_MH_REQUEST_SRC_SPECIFIC 15
/* sub-TLVs */
#define MESSAGE_SUB_PAD1 0
#define MESSAGE_SUB_PADN 1
#define MESSAGE_SUB_DIVERSITY 2
#define MESSAGE_SUB_TIMESTAMP 3
/* Diversity sub-TLV channel codes */
static const struct tok diversity_str[] = {
{ 0, "reserved" },
{ 255, "all" },
{ 0, NULL }
};
static const char *
format_id(const u_char *id)
{
static char buf[25];
snprintf(buf, 25, "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x",
id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7]);
buf[24] = '\0';
return buf;
}
static const unsigned char v4prefix[16] =
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
static const char *
format_prefix(netdissect_options *ndo, const u_char *prefix, unsigned char plen)
{
static char buf[50];
if(plen >= 96 && memcmp(prefix, v4prefix, 12) == 0)
snprintf(buf, 50, "%s/%u", ipaddr_string(ndo, prefix + 12), plen - 96);
else
#ifdef INET6
snprintf(buf, 50, "%s/%u", ip6addr_string(ndo, prefix), plen);
#else
snprintf(buf, 50, "IPv6 addresses not supported");
#endif
buf[49] = '\0';
return buf;
}
static const char *
format_address(netdissect_options *ndo, const u_char *prefix)
{
if(memcmp(prefix, v4prefix, 12) == 0)
return ipaddr_string(ndo, prefix + 12);
else
#ifdef INET6
return ip6addr_string(ndo, prefix);
#else
return "IPv6 addresses not supported";
#endif
}
static const char *
format_interval(const uint16_t i)
{
static char buf[sizeof("000.00s")];
if (i == 0)
return "0.0s (bogus)";
snprintf(buf, sizeof(buf), "%u.%02us", i / 100, i % 100);
return buf;
}
static const char *
format_interval_update(const uint16_t i)
{
return i == 0xFFFF ? "infinity" : format_interval(i);
}
static const char *
format_timestamp(const uint32_t i)
{
static char buf[sizeof("0000.000000s")];
snprintf(buf, sizeof(buf), "%u.%06us", i / 1000000, i % 1000000);
return buf;
}
/* Return number of octets consumed from the input buffer (not the prefix length
* in bytes), or -1 for encoding error. */
static int
network_prefix(int ae, int plen, unsigned int omitted,
const unsigned char *p, const unsigned char *dp,
unsigned int len, unsigned char *p_r)
{
unsigned pb;
unsigned char prefix[16];
int consumed = 0;
if(plen >= 0)
pb = (plen + 7) / 8;
else if(ae == 1)
pb = 4;
else
pb = 16;
if(pb > 16)
return -1;
memset(prefix, 0, 16);
switch(ae) {
case 0: break;
case 1:
if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
return -1;
memcpy(prefix, v4prefix, 12);
if(omitted) {
if (dp == NULL) return -1;
memcpy(prefix, dp, 12 + omitted);
}
if(pb > omitted) {
memcpy(prefix + 12 + omitted, p, pb - omitted);
consumed = pb - omitted;
}
break;
case 2:
if(omitted > 16 || (pb > omitted && len < pb - omitted))
return -1;
if(omitted) {
if (dp == NULL) return -1;
memcpy(prefix, dp, omitted);
}
if(pb > omitted) {
memcpy(prefix + omitted, p, pb - omitted);
consumed = pb - omitted;
}
break;
case 3:
if(pb > 8 && len < pb - 8) return -1;
prefix[0] = 0xfe;
prefix[1] = 0x80;
if(pb > 8) {
memcpy(prefix + 8, p, pb - 8);
consumed = pb - 8;
}
break;
default:
return -1;
}
memcpy(p_r, prefix, 16);
return consumed;
}
static int
network_address(int ae, const unsigned char *a, unsigned int len,
unsigned char *a_r)
{
return network_prefix(ae, -1, 0, a, NULL, len, a_r);
}
/*
* Sub-TLVs consume the "extra data" of Babel TLVs (see Section 4.3 of RFC6126),
* their encoding is similar to the encoding of TLVs, but the type namespace is
* different:
*
* o Type 0 stands for Pad1 sub-TLV with the same encoding as the Pad1 TLV.
* o Type 1 stands for PadN sub-TLV with the same encoding as the PadN TLV.
* o Type 2 stands for Diversity sub-TLV, which propagates diversity routing
* data. Its body is a variable-length sequence of 8-bit unsigned integers,
* each representing per-hop number of interferring radio channel for the
* prefix. Channel 0 is invalid and must not be used in the sub-TLV, channel
* 255 interferes with any other channel.
* o Type 3 stands for Timestamp sub-TLV, used to compute RTT between
* neighbours. In the case of a Hello TLV, the body stores a 32-bits
* timestamp, while in the case of a IHU TLV, two 32-bits timestamps are
* stored.
*
* Sub-TLV types 0 and 1 are valid for any TLV type, whether sub-TLV type 2 is
* only valid for TLV type 8 (Update). Note that within an Update TLV a missing
* Diversity sub-TLV is not the same as a Diversity sub-TLV with an empty body.
* The former would mean a lack of any claims about the interference, and the
* latter would state that interference is definitely absent.
* A type 3 sub-TLV is valid both for Hello and IHU TLVs, though the exact
* semantic of the sub-TLV is different in each case.
*/
static void
subtlvs_print(netdissect_options *ndo,
const u_char *cp, const u_char *ep, const uint8_t tlv_type)
{
uint8_t subtype, sublen;
const char *sep;
uint32_t t1, t2;
while (cp < ep) {
subtype = *cp++;
if(subtype == MESSAGE_SUB_PAD1) {
ND_PRINT((ndo, " sub-pad1"));
continue;
}
if(cp == ep)
goto corrupt;
sublen = *cp++;
if(cp + sublen > ep)
goto corrupt;
switch(subtype) {
case MESSAGE_SUB_PADN:
ND_PRINT((ndo, " sub-padn"));
cp += sublen;
break;
case MESSAGE_SUB_DIVERSITY:
ND_PRINT((ndo, " sub-diversity"));
if (sublen == 0) {
ND_PRINT((ndo, " empty"));
break;
}
sep = " ";
while(sublen--) {
ND_PRINT((ndo, "%s%s", sep, tok2str(diversity_str, "%u", *cp++)));
sep = "-";
}
if(tlv_type != MESSAGE_UPDATE &&
tlv_type != MESSAGE_UPDATE_SRC_SPECIFIC)
ND_PRINT((ndo, " (bogus)"));
break;
case MESSAGE_SUB_TIMESTAMP:
ND_PRINT((ndo, " sub-timestamp"));
if(tlv_type == MESSAGE_HELLO) {
if(sublen < 4)
goto corrupt;
t1 = EXTRACT_32BITS(cp);
ND_PRINT((ndo, " %s", format_timestamp(t1)));
} else if(tlv_type == MESSAGE_IHU) {
if(sublen < 8)
goto corrupt;
t1 = EXTRACT_32BITS(cp);
ND_PRINT((ndo, " %s", format_timestamp(t1)));
t2 = EXTRACT_32BITS(cp + 4);
ND_PRINT((ndo, "|%s", format_timestamp(t2)));
} else
ND_PRINT((ndo, " (bogus)"));
cp += sublen;
break;
default:
ND_PRINT((ndo, " sub-unknown-0x%02x", subtype));
cp += sublen;
} /* switch */
} /* while */
return;
corrupt:
ND_PRINT((ndo, " (corrupt)"));
}
#define ICHECK(i, l) \
if ((i) + (l) > bodylen || (i) + (l) > length) goto corrupt;
static void
babel_print_v2(netdissect_options *ndo,
const u_char *cp, u_int length)
{
u_int i;
u_short bodylen;
u_char v4_prefix[16] =
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
u_char v6_prefix[16] = {0};
ND_TCHECK2(*cp, 4);
if (length < 4)
goto corrupt;
bodylen = EXTRACT_16BITS(cp + 2);
ND_PRINT((ndo, " (%u)", bodylen));
/* Process the TLVs in the body */
i = 0;
while(i < bodylen) {
const u_char *message;
u_int type, len;
message = cp + 4 + i;
ND_TCHECK2(*message, 1);
if((type = message[0]) == MESSAGE_PAD1) {
ND_PRINT((ndo, ndo->ndo_vflag ? "\n\tPad 1" : " pad1"));
i += 1;
continue;
}
ND_TCHECK2(*message, 2);
ICHECK(i, 2);
len = message[1];
ND_TCHECK2(*message, 2 + len);
ICHECK(i, 2 + len);
switch(type) {
case MESSAGE_PADN: {
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " padN"));
else
ND_PRINT((ndo, "\n\tPad %d", len + 2));
}
break;
case MESSAGE_ACK_REQ: {
u_short nonce, interval;
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " ack-req"));
else {
ND_PRINT((ndo, "\n\tAcknowledgment Request "));
if(len < 6) goto corrupt;
nonce = EXTRACT_16BITS(message + 4);
interval = EXTRACT_16BITS(message + 6);
ND_PRINT((ndo, "%04x %s", nonce, format_interval(interval)));
}
}
break;
case MESSAGE_ACK: {
u_short nonce;
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " ack"));
else {
ND_PRINT((ndo, "\n\tAcknowledgment "));
if(len < 2) goto corrupt;
nonce = EXTRACT_16BITS(message + 2);
ND_PRINT((ndo, "%04x", nonce));
}
}
break;
case MESSAGE_HELLO: {
u_short seqno, interval;
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " hello"));
else {
ND_PRINT((ndo, "\n\tHello "));
if(len < 6) goto corrupt;
seqno = EXTRACT_16BITS(message + 4);
interval = EXTRACT_16BITS(message + 6);
ND_PRINT((ndo, "seqno %u interval %s", seqno, format_interval(interval)));
/* Extra data. */
if(len > 6)
subtlvs_print(ndo, message + 8, message + 2 + len, type);
}
}
break;
case MESSAGE_IHU: {
unsigned short txcost, interval;
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " ihu"));
else {
u_char address[16];
int rc;
ND_PRINT((ndo, "\n\tIHU "));
if(len < 6) goto corrupt;
txcost = EXTRACT_16BITS(message + 4);
interval = EXTRACT_16BITS(message + 6);
rc = network_address(message[2], message + 8, len - 6, address);
if(rc < 0) { ND_PRINT((ndo, "%s", tstr)); break; }
ND_PRINT((ndo, "%s txcost %u interval %s",
format_address(ndo, address), txcost, format_interval(interval)));
/* Extra data. */
if((u_int)rc < len - 6)
subtlvs_print(ndo, message + 8 + rc, message + 2 + len,
type);
}
}
break;
case MESSAGE_ROUTER_ID: {
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " router-id"));
else {
ND_PRINT((ndo, "\n\tRouter Id"));
if(len < 10) goto corrupt;
ND_PRINT((ndo, " %s", format_id(message + 4)));
}
}
break;
case MESSAGE_NH: {
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " nh"));
else {
int rc;
u_char nh[16];
ND_PRINT((ndo, "\n\tNext Hop"));
if(len < 2) goto corrupt;
rc = network_address(message[2], message + 4, len - 2, nh);
if(rc < 0) goto corrupt;
ND_PRINT((ndo, " %s", format_address(ndo, nh)));
}
}
break;
case MESSAGE_UPDATE: {
if (!ndo->ndo_vflag) {
ND_PRINT((ndo, " update"));
if(len < 1)
ND_PRINT((ndo, "/truncated"));
else
ND_PRINT((ndo, "%s%s%s",
(message[3] & 0x80) ? "/prefix": "",
(message[3] & 0x40) ? "/id" : "",
(message[3] & 0x3f) ? "/unknown" : ""));
} else {
u_short interval, seqno, metric;
u_char plen;
int rc;
u_char prefix[16];
ND_PRINT((ndo, "\n\tUpdate"));
if(len < 10) goto corrupt;
plen = message[4] + (message[2] == 1 ? 96 : 0);
rc = network_prefix(message[2], message[4], message[5],
message + 12,
message[2] == 1 ? v4_prefix : v6_prefix,
len - 10, prefix);
if(rc < 0) goto corrupt;
interval = EXTRACT_16BITS(message + 6);
seqno = EXTRACT_16BITS(message + 8);
metric = EXTRACT_16BITS(message + 10);
ND_PRINT((ndo, "%s%s%s %s metric %u seqno %u interval %s",
(message[3] & 0x80) ? "/prefix": "",
(message[3] & 0x40) ? "/id" : "",
(message[3] & 0x3f) ? "/unknown" : "",
format_prefix(ndo, prefix, plen),
metric, seqno, format_interval_update(interval)));
if(message[3] & 0x80) {
if(message[2] == 1)
memcpy(v4_prefix, prefix, 16);
else
memcpy(v6_prefix, prefix, 16);
}
/* extra data? */
if((u_int)rc < len - 10)
subtlvs_print(ndo, message + 12 + rc, message + 2 + len, type);
}
}
break;
case MESSAGE_REQUEST: {
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " request"));
else {
int rc;
u_char prefix[16], plen;
ND_PRINT((ndo, "\n\tRequest "));
if(len < 2) goto corrupt;
plen = message[3] + (message[2] == 1 ? 96 : 0);
rc = network_prefix(message[2], message[3], 0,
message + 4, NULL, len - 2, prefix);
if(rc < 0) goto corrupt;
ND_PRINT((ndo, "for %s",
message[2] == 0 ? "any" : format_prefix(ndo, prefix, plen)));
}
}
break;
case MESSAGE_MH_REQUEST : {
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " mh-request"));
else {
int rc;
u_short seqno;
u_char prefix[16], plen;
ND_PRINT((ndo, "\n\tMH-Request "));
if(len < 14) goto corrupt;
seqno = EXTRACT_16BITS(message + 4);
rc = network_prefix(message[2], message[3], 0,
message + 16, NULL, len - 14, prefix);
if(rc < 0) goto corrupt;
plen = message[3] + (message[2] == 1 ? 96 : 0);
ND_PRINT((ndo, "(%u hops) for %s seqno %u id %s",
message[6], format_prefix(ndo, prefix, plen),
seqno, format_id(message + 8)));
}
}
break;
case MESSAGE_TSPC :
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " tspc"));
else {
ND_PRINT((ndo, "\n\tTS/PC "));
if(len < 6) goto corrupt;
ND_PRINT((ndo, "timestamp %u packetcounter %u", EXTRACT_32BITS (message + 4),
EXTRACT_16BITS(message + 2)));
}
break;
case MESSAGE_HMAC : {
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " hmac"));
else {
unsigned j;
ND_PRINT((ndo, "\n\tHMAC "));
if(len < 18) goto corrupt;
ND_PRINT((ndo, "key-id %u digest-%u ", EXTRACT_16BITS(message + 2), len - 2));
for (j = 0; j < len - 2; j++)
ND_PRINT((ndo, "%02X", message[4 + j]));
}
}
break;
case MESSAGE_UPDATE_SRC_SPECIFIC : {
if(!ndo->ndo_vflag) {
ND_PRINT((ndo, " ss-update"));
} else {
u_char prefix[16], src_prefix[16];
u_short interval, seqno, metric;
u_char ae, plen, src_plen, omitted;
int rc;
int parsed_len = 10;
ND_PRINT((ndo, "\n\tSS-Update"));
if(len < 10) goto corrupt;
ae = message[2];
src_plen = message[3];
plen = message[4];
omitted = message[5];
interval = EXTRACT_16BITS(message + 6);
seqno = EXTRACT_16BITS(message + 8);
metric = EXTRACT_16BITS(message + 10);
rc = network_prefix(ae, plen, omitted, message + 2 + parsed_len,
ae == 1 ? v4_prefix : v6_prefix,
len - parsed_len, prefix);
if(rc < 0) goto corrupt;
if(ae == 1)
plen += 96;
parsed_len += rc;
rc = network_prefix(ae, src_plen, 0, message + 2 + parsed_len,
NULL, len - parsed_len, src_prefix);
if(rc < 0) goto corrupt;
if(ae == 1)
src_plen += 96;
parsed_len += rc;
ND_PRINT((ndo, " %s from", format_prefix(ndo, prefix, plen)));
ND_PRINT((ndo, " %s metric %u seqno %u interval %s",
format_prefix(ndo, src_prefix, src_plen),
metric, seqno, format_interval_update(interval)));
/* extra data? */
if((u_int)parsed_len < len)
subtlvs_print(ndo, message + 2 + parsed_len,
message + 2 + len, type);
}
}
break;
case MESSAGE_REQUEST_SRC_SPECIFIC : {
if(!ndo->ndo_vflag)
ND_PRINT((ndo, " ss-request"));
else {
int rc, parsed_len = 3;
u_char ae, plen, src_plen, prefix[16], src_prefix[16];
ND_PRINT((ndo, "\n\tSS-Request "));
if(len < 3) goto corrupt;
ae = message[2];
plen = message[3];
src_plen = message[4];
rc = network_prefix(ae, plen, 0, message + 2 + parsed_len,
NULL, len - parsed_len, prefix);
if(rc < 0) goto corrupt;
if(ae == 1)
plen += 96;
parsed_len += rc;
rc = network_prefix(ae, src_plen, 0, message + 2 + parsed_len,
NULL, len - parsed_len, src_prefix);
if(rc < 0) goto corrupt;
if(ae == 1)
src_plen += 96;
parsed_len += rc;
if(ae == 0) {
ND_PRINT((ndo, "for any"));
} else {
ND_PRINT((ndo, "for (%s, ", format_prefix(ndo, prefix, plen)));
ND_PRINT((ndo, "%s)", format_prefix(ndo, src_prefix, src_plen)));
}
}
}
break;
case MESSAGE_MH_REQUEST_SRC_SPECIFIC : {
if(!ndo->ndo_vflag)
ND_PRINT((ndo, " ss-mh-request"));
else {
int rc, parsed_len = 14;
u_short seqno;
u_char ae, plen, src_plen, prefix[16], src_prefix[16], hopc;
const u_char *router_id = NULL;
ND_PRINT((ndo, "\n\tSS-MH-Request "));
if(len < 14) goto corrupt;
ae = message[2];
plen = message[3];
seqno = EXTRACT_16BITS(message + 4);
hopc = message[6];
src_plen = message[7];
router_id = message + 8;
rc = network_prefix(ae, plen, 0, message + 2 + parsed_len,
NULL, len - parsed_len, prefix);
if(rc < 0) goto corrupt;
if(ae == 1)
plen += 96;
parsed_len += rc;
rc = network_prefix(ae, src_plen, 0, message + 2 + parsed_len,
NULL, len - parsed_len, src_prefix);
if(rc < 0) goto corrupt;
if(ae == 1)
src_plen += 96;
ND_PRINT((ndo, "(%u hops) for (%s, ",
message[6], format_prefix(ndo, prefix, plen)));
ND_PRINT((ndo, "%s) seqno %u id %s",
format_prefix(ndo, src_prefix, src_plen),
seqno, format_id(message + 8)));
}
}
break;
default:
if (!ndo->ndo_vflag)
ND_PRINT((ndo, " unknown"));
else
ND_PRINT((ndo, "\n\tUnknown message type %d", type));
}
i += len + 2;
}
return;
trunc:
ND_PRINT((ndo, " %s", tstr));
return;
corrupt:
ND_PRINT((ndo, " (corrupt)"));
return;
}
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