/*
* RFC3032: MPLS label stack encoding
*/
void
mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
{
const u_char *p;
uint32_t label_entry;
uint16_t label_stack_depth = 0;
enum mpls_packet_type pt = PT_UNKNOWN;
p = bp;
ND_PRINT((ndo, "MPLS"));
do {
ND_TCHECK2(*p, sizeof(label_entry));
label_entry = EXTRACT_32BITS(p);
ND_PRINT((ndo, "%s(label %u",
(label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
MPLS_LABEL(label_entry)));
label_stack_depth++;
if (ndo->ndo_vflag &&
MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)]));
ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry)));
if (MPLS_STACK(label_entry))
ND_PRINT((ndo, ", [S]"));
ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry)));
p += sizeof(label_entry);
} while (!MPLS_STACK(label_entry));
/*
* Try to figure out the packet type.
*/
switch (MPLS_LABEL(label_entry)) {
case 0: /* IPv4 explicit NULL label */
case 3: /* IPv4 implicit NULL label */
pt = PT_IPV4;
break;
case 2: /* IPv6 explicit NULL label */
pt = PT_IPV6;
break;
default:
/*
* Generally there's no indication of protocol in MPLS label
* encoding.
*
* However, draft-hsmit-isis-aal5mux-00.txt describes a
* technique for encapsulating IS-IS and IP traffic on the
* same ATM virtual circuit; you look at the first payload
* byte to determine the network layer protocol, based on
* the fact that
*
* 1) the first byte of an IP header is 0x45-0x4f
* for IPv4 and 0x60-0x6f for IPv6;
*
* 2) the first byte of an OSI CLNP packet is 0x81,
* the first byte of an OSI ES-IS packet is 0x82,
* and the first byte of an OSI IS-IS packet is
* 0x83;
*
* so the network layer protocol can be inferred from the
* first byte of the packet, if the protocol is one of the
* ones listed above.
*
* Cisco sends control-plane traffic MPLS-encapsulated in
* this fashion.
*/
switch(*p) {
case 0x45:
case 0x46:
case 0x47:
case 0x48:
case 0x49:
case 0x4a:
case 0x4b:
case 0x4c:
case 0x4d:
case 0x4e:
case 0x4f:
pt = PT_IPV4;
break;
case 0x60:
case 0x61:
case 0x62:
case 0x63:
case 0x64:
case 0x65:
case 0x66:
case 0x67:
case 0x68:
case 0x69:
case 0x6a:
case 0x6b:
case 0x6c:
case 0x6d:
case 0x6e:
case 0x6f:
pt = PT_IPV6;
break;
case 0x81:
case 0x82:
case 0x83:
pt = PT_OSI;
break;
default:
/* ok bail out - we did not figure out what it is*/
break;
}
}
/*
* Print the payload.
*/
if (pt == PT_UNKNOWN) {
if (!ndo->ndo_suppress_default_print)
ND_DEFAULTPRINT(p, length - (p - bp));
return;
}
ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " "));
switch (pt) {
case PT_IPV4:
ip_print(ndo, p, length - (p - bp));
break;
case PT_IPV6:
ip6_print(ndo, p, length - (p - bp));
break;
case PT_OSI:
isoclns_print(ndo, p, length - (p - bp), length - (p - bp));
break;
default:
break;
}
return;
trunc:
ND_PRINT((ndo, "[|MPLS]"));
}
void
icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
{
char *cp;
const struct icmp *dp;
const struct icmp_ext_t *ext_dp;
const struct ip *ip;
const char *str, *fmt;
const struct ip *oip;
const struct udphdr *ouh;
const u_int8_t *obj_tptr;
u_int32_t raw_label;
const u_char *snapend_save;
const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
char buf[MAXHOSTNAMELEN + 100];
dp = (struct icmp *)bp;
ext_dp = (struct icmp_ext_t *)bp;
ip = (struct ip *)bp2;
str = buf;
TCHECK(dp->icmp_code);
switch (dp->icmp_type) {
case ICMP_ECHO:
case ICMP_ECHOREPLY:
TCHECK(dp->icmp_seq);
(void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
dp->icmp_type == ICMP_ECHO ?
"request" : "reply",
EXTRACT_16BITS(&dp->icmp_id),
EXTRACT_16BITS(&dp->icmp_seq));
break;
case ICMP_UNREACH:
TCHECK(dp->icmp_ip.ip_dst);
switch (dp->icmp_code) {
case ICMP_UNREACH_PROTOCOL:
TCHECK(dp->icmp_ip.ip_p);
(void)snprintf(buf, sizeof(buf),
"%s protocol %d unreachable",
ipaddr_string(&dp->icmp_ip.ip_dst),
dp->icmp_ip.ip_p);
break;
case ICMP_UNREACH_PORT:
TCHECK(dp->icmp_ip.ip_p);
oip = &dp->icmp_ip;
hlen = IP_HL(oip) * 4;
ouh = (struct udphdr *)(((u_char *)oip) + hlen);
TCHECK(ouh->uh_dport);
dport = EXTRACT_16BITS(&ouh->uh_dport);
switch (oip->ip_p) {
case IPPROTO_TCP:
(void)snprintf(buf, sizeof(buf),
"%s tcp port %s unreachable",
ipaddr_string(&oip->ip_dst),
tcpport_string(dport));
break;
case IPPROTO_UDP:
(void)snprintf(buf, sizeof(buf),
"%s udp port %s unreachable",
ipaddr_string(&oip->ip_dst),
udpport_string(dport));
break;
default:
(void)snprintf(buf, sizeof(buf),
"%s protocol %d port %d unreachable",
ipaddr_string(&oip->ip_dst),
oip->ip_p, dport);
break;
}
break;
case ICMP_UNREACH_NEEDFRAG:
{
register const struct mtu_discovery *mp;
mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
mtu = EXTRACT_16BITS(&mp->nexthopmtu);
if (mtu) {
(void)snprintf(buf, sizeof(buf),
"%s unreachable - need to frag (mtu %d)",
ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
} else {
(void)snprintf(buf, sizeof(buf),
"%s unreachable - need to frag",
ipaddr_string(&dp->icmp_ip.ip_dst));
}
}
break;
default:
fmt = tok2str(unreach2str, "#%d %%s unreachable",
dp->icmp_code);
(void)snprintf(buf, sizeof(buf), fmt,
ipaddr_string(&dp->icmp_ip.ip_dst));
break;
}
break;
case ICMP_REDIRECT:
TCHECK(dp->icmp_ip.ip_dst);
fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
dp->icmp_code);
(void)snprintf(buf, sizeof(buf), fmt,
ipaddr_string(&dp->icmp_ip.ip_dst),
ipaddr_string(&dp->icmp_gwaddr));
break;
case ICMP_ROUTERADVERT:
{
register const struct ih_rdiscovery *ihp;
register const struct id_rdiscovery *idp;
u_int lifetime, num, size;
(void)snprintf(buf, sizeof(buf), "router advertisement");
cp = buf + strlen(buf);
ihp = (struct ih_rdiscovery *)&dp->icmp_void;
TCHECK(*ihp);
(void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
cp = buf + strlen(buf);
lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
if (lifetime < 60) {
(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
lifetime);
} else if (lifetime < 60 * 60) {
(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
lifetime / 60, lifetime % 60);
} else {
(void)snprintf(cp, sizeof(buf) - (cp - buf),
"%u:%02u:%02u",
lifetime / 3600,
(lifetime % 3600) / 60,
lifetime % 60);
}
cp = buf + strlen(buf);
num = ihp->ird_addrnum;
(void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
cp = buf + strlen(buf);
size = ihp->ird_addrsiz;
if (size != 2) {
(void)snprintf(cp, sizeof(buf) - (cp - buf),
" [size %d]", size);
break;
}
idp = (struct id_rdiscovery *)&dp->icmp_data;
while (num-- > 0) {
TCHECK(*idp);
(void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
ipaddr_string(&idp->ird_addr),
EXTRACT_32BITS(&idp->ird_pref));
cp = buf + strlen(buf);
++idp;
}
}
break;
case ICMP_TIMXCEED:
TCHECK(dp->icmp_ip.ip_dst);
switch (dp->icmp_code) {
case ICMP_TIMXCEED_INTRANS:
str = "time exceeded in-transit";
break;
case ICMP_TIMXCEED_REASS:
str = "ip reassembly time exceeded";
break;
default:
(void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
dp->icmp_code);
break;
}
break;
case ICMP_PARAMPROB:
if (dp->icmp_code)
(void)snprintf(buf, sizeof(buf),
"parameter problem - code %d", dp->icmp_code);
else {
TCHECK(dp->icmp_pptr);
(void)snprintf(buf, sizeof(buf),
"parameter problem - octet %d", dp->icmp_pptr);
}
break;
case ICMP_MASKREPLY:
TCHECK(dp->icmp_mask);
(void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
EXTRACT_32BITS(&dp->icmp_mask));
break;
case ICMP_TSTAMP:
TCHECK(dp->icmp_seq);
(void)snprintf(buf, sizeof(buf),
"time stamp query id %u seq %u",
EXTRACT_16BITS(&dp->icmp_id),
EXTRACT_16BITS(&dp->icmp_seq));
break;
case ICMP_TSTAMPREPLY:
TCHECK(dp->icmp_ttime);
(void)snprintf(buf, sizeof(buf),
"time stamp reply id %u seq %u: org %s",
EXTRACT_16BITS(&dp->icmp_id),
EXTRACT_16BITS(&dp->icmp_seq),
icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
(void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
(void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
break;
default:
str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
break;
}
(void)printf("ICMP %s, length %u", str, plen);
if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
u_int16_t sum, icmp_sum;
if (TTEST2(*bp, plen)) {
sum = in_cksum((u_short*)dp, plen, 0);
if (sum != 0) {
icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
(void)printf(" (wrong icmp cksum %x (->%x)!)",
icmp_sum,
in_cksum_shouldbe(icmp_sum, sum));
}
}
}
/*
* print the remnants of the IP packet.
* save the snaplength as this may get overidden in the IP printer.
*/
if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
bp += 8;
(void)printf("\n\t");
ip = (struct ip *)bp;
snaplen = snapend - bp;
snapend_save = snapend;
ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len));
snapend = snapend_save;
}
/*
* Attempt to decode the MPLS extensions only for some ICMP types.
*/
if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
TCHECK(*ext_dp);
/*
* Check first if the mpls extension header shows a non-zero length.
* If the length field is not set then silently verify the checksum
* to check if an extension header is present. This is expedient,
* however not all implementations set the length field proper.
*/
if (!ext_dp->icmp_length &&
in_cksum((const u_short *)&ext_dp->icmp_ext_version_res,
plen - ICMP_EXTD_MINLEN, 0)) {
return;
}
printf("\n\tMPLS extension v%u",
ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
/*
* Sanity checking of the header.
*/
if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
ICMP_MPLS_EXT_VERSION) {
printf(" packet not supported");
return;
}
hlen = plen - ICMP_EXTD_MINLEN;
printf(", checksum 0x%04x (%scorrect), length %u",
EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
in_cksum((const u_short *)&ext_dp->icmp_ext_version_res,
plen - ICMP_EXTD_MINLEN, 0) ? "in" : "",
hlen);
hlen -= 4; /* subtract common header size */
obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
TCHECK(*icmp_mpls_ext_object_header);
obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
obj_class_num = icmp_mpls_ext_object_header->class_num;
obj_ctype = icmp_mpls_ext_object_header->ctype;
obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
printf("\n\t %s Object (%u), Class-Type: %u, length %u",
tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
obj_class_num,
obj_ctype,
obj_tlen);
hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
/* infinite loop protection */
if ((obj_class_num == 0) ||
(obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
return;
}
obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
switch (obj_class_num) {
case 1:
switch(obj_ctype) {
case 1:
TCHECK2(*obj_tptr, 4);
raw_label = EXTRACT_32BITS(obj_tptr);
printf("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
if (MPLS_STACK(raw_label))
printf(", [S]");
printf(", ttl %u", MPLS_TTL(raw_label));
break;
default:
print_unknown_data(obj_tptr, "\n\t ", obj_tlen);
}
break;
/*
* FIXME those are the defined objects that lack a decoder
* you are welcome to contribute code ;-)
*/
case 2:
default:
print_unknown_data(obj_tptr, "\n\t ", obj_tlen);
break;
}
if (hlen < obj_tlen)
break;
hlen -= obj_tlen;
obj_tptr += obj_tlen;
}
}
return;
trunc:
fputs("[|icmp]", stdout);
}
/*
* RFC3032: MPLS label stack encoding
*/
void
mpls_print(const u_char *bp, u_int length)
{
const u_char *p;
u_int32_t label_entry;
u_int16_t label_stack_depth = 0;
p = bp;
printf("MPLS");
do {
TCHECK2(*p, sizeof(label_entry));
label_entry = EXTRACT_32BITS(p);
printf("%s(label %u",
label_stack_depth ? "\n\t" : " ",
MPLS_LABEL(label_entry));
label_stack_depth++;
if (vflag &&
MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
printf(", exp %u", MPLS_EXP(label_entry));
if (MPLS_STACK(label_entry))
printf(", [S]");
printf(", ttl %u)", MPLS_TTL(label_entry));
p += sizeof(label_entry);
} while (!MPLS_STACK(label_entry));
switch (MPLS_LABEL(label_entry)) {
case 0: /* IPv4 explicit NULL label */
case 3: /* IPv4 implicit NULL label */
if (vflag>0) {
printf("\n\t");
ip_print(gndo, p, length - (p - bp));
}
else printf(", IP, length: %u",length);
break;
#ifdef INET6
case 2: /* IPv6 explicit NULL label */
if (vflag>0) {
printf("\n\t");
ip6_print(p, length - (p - bp));
}
else printf(", IPv6, length: %u",length);
break;
#endif
default:
/*
* Generally there's no indication of protocol in MPLS label
* encoding, however draft-hsmit-isis-aal5mux-00.txt describes
* a technique that looks at the first payload byte if the BOS (bottom of stack)
* bit is set and tries to determine the network layer protocol
* 0x45-0x4f is IPv4
* 0x60-0x6f is IPv6
* 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
* this technique is sometimes known as NULL encapsulation
* and decoding is particularly useful for control-plane traffic [BGP]
* which cisco by default sends MPLS encapsulated
*/
if (MPLS_STACK(label_entry)) { /* only do this if the stack bit is set */
switch(*p) {
case 0x45:
case 0x46:
case 0x47:
case 0x48:
case 0x49:
case 0x4a:
case 0x4b:
case 0x4c:
case 0x4d:
case 0x4e:
case 0x4f:
if (vflag>0) {
printf("\n\t");
ip_print(gndo, p, length - (p - bp));
}
else printf(", IP, length: %u",length);
break;
#ifdef INET6
case 0x60:
case 0x61:
case 0x62:
case 0x63:
case 0x64:
case 0x65:
case 0x66:
case 0x67:
case 0x68:
case 0x69:
case 0x6a:
case 0x6b:
case 0x6c:
case 0x6d:
case 0x6e:
case 0x6f:
if (vflag>0) {
printf("\n\t");
ip6_print(p, length - (p - bp));
}
else printf(", IPv6, length: %u",length);
break;
#endif
case 0x81:
case 0x82:
case 0x83:
if (vflag>0) {
printf("\n\t");
isoclns_print(p, length - (p - bp), length - (p - bp));
}
else printf(", OSI, length: %u",length);
break;
default:
/* ok bail out - we did not figure out what it is*/
break;
}
}
return;
}
trunc:
printf("[|MPLS]");
}
