/*

* 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.

*/

#define NETDISSECT_REWORKED

#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

/* sub-TLVs */

#define MESSAGE_SUB_PAD1 0

#define MESSAGE_SUB_PADN 1

#define MESSAGE_SUB_DIVERSITY 2

/* 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 u_int16_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 u_int16_t i)

{

return i == 0xFFFF ? "infinity" : format_interval(i);

}

/* 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.

*

* 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. */

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;

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)

ND_PRINT((ndo, " (bogus)"));

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)));

}

}

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)));

}

}

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;

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;

}