/*
* Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Code by Matt Thomas, Digital Equipment Corporation
* with an awful lot of hacking by Jeffrey Mogul, DECWRL
*/
/*
* If we printed information about the payload, returns the length of the LLC
* header, plus the length of any SNAP header following it.
*
* Otherwise (for example, if the packet has unknown SAPs or has a SNAP
* header with an unknown OUI/PID combination), returns the *negative*
* of that value.
*/
int
llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
const struct lladdr_info *src, const struct lladdr_info *dst)
{
uint8_t dsap_field, dsap, ssap_field, ssap;
uint16_t control;
int hdrlen;
int is_u;
/*
* OK, what type of LLC frame is this? The length
* of the control field depends on that - I frames
* have a two-byte control field, and U frames have
* a one-byte control field.
*/
control = GET_U_1(p + 2);
if ((control & LLC_U_FMT) == LLC_U_FMT) {
/*
* U frame.
*/
is_u = 1;
hdrlen = 3; /* DSAP, SSAP, 1-byte control field */
} else {
/*
* The control field in I and S frames is
* 2 bytes...
*/
if (caplen < 4) {
nd_print_trunc(ndo);
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (caplen);
}
if (length < 4) {
nd_print_trunc(ndo);
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (length);
}
/*
* ...and is little-endian.
*/
control = GET_LE_U_2(p + 2);
is_u = 0;
hdrlen = 4; /* DSAP, SSAP, 2-byte control field */
}
if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
/*
* This is an Ethernet_802.3 IPX frame; it has an
* 802.3 header (i.e., an Ethernet header where the
* type/length field is <= MAX_ETHERNET_LENGTH_VAL,
* i.e. it's a length field, not a type field), but
* has no 802.2 header - the IPX packet starts right
* after the Ethernet header, with a signature of two
* bytes of 0xFF (which is LLCSAP_GLOBAL).
*
* (It might also have been an Ethernet_802.3 IPX at
* one time, but got bridged onto another network,
* such as an 802.11 network; this has appeared in at
* least one capture file.)
*/
if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
&& control == LLC_UI) {
/*
* XXX - what *is* the right bridge pad value here?
* Does anybody ever bridge one form of LAN traffic
* over a networking type that uses 802.2 LLC?
*/
if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
/*
* Unknown packet type; tell our caller, by
* returning a negative value, so they
* can print the raw packet.
*/
return (-(hdrlen + 5)); /* include LLC and SNAP header */
} else
return (hdrlen + 5); /* include LLC and SNAP header */
}
if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
control == LLC_UI) {
stp_print(ndo, p, length);
return (hdrlen);
}
if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
control == LLC_UI) {
/*
* This is an RFC 948-style IP packet, with
* an 802.3 header and an 802.2 LLC header
* with the source and destination SAPs being
* the IP SAP.
*/
ip_print(ndo, p, length);
return (hdrlen);
}
if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
control == LLC_UI) {
/*
* This is an Ethernet_802.2 IPX frame, with an 802.3
* header and an 802.2 LLC header with the source and
* destination SAPs being the IPX SAP.
*/
if (ndo->ndo_eflag)
ND_PRINT("IPX 802.2: ");
ipx_print(ndo, p, length);
return (hdrlen);
}
#ifdef ENABLE_SMB
if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
&& (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
/*
* we don't actually have a full netbeui parser yet, but the
* smb parser can handle many smb-in-netbeui packets, which
* is very useful, so we call that
*
* We don't call it for S frames, however, just I frames
* (which are frames that don't have the low-order bit,
* LLC_S_FMT, set in the first byte of the control field)
* and UI frames (whose control field is just 3, LLC_U_FMT).
*/
netbeui_print(ndo, control, p, length);
return (hdrlen);
}
#endif
if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
&& control == LLC_UI) {
isoclns_print(ndo, p, length);
return (hdrlen);
}
if (ndo->ndo_eflag) {
/*
* Somebody's already printed the MAC addresses, if there
* are any, so just print the SNAP header, not the MAC
* addresses.
*/
ND_PRINT("oui %s (0x%06x), %s %s (0x%04x), length %u: ",
tok2str(oui_values, "Unknown", orgcode),
orgcode,
(orgcode == 0x000000 ? "ethertype" : "pid"),
tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
et, length - 5);
}
p += 5;
length -= 5;
caplen -= 5;
switch (orgcode) {
case OUI_ENCAP_ETHER:
case OUI_CISCO_90:
/*
* This is an encapsulated Ethernet packet,
* or a packet bridged by some piece of
* Cisco hardware; the protocol ID is
* an Ethernet protocol type.
*/
ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
if (ret)
return (ret);
break;
case OUI_APPLETALK:
if (et == ETHERTYPE_ATALK) {
/*
* No, I have no idea why Apple used one
* of their own OUIs, rather than
* 0x000000, and an Ethernet packet
* type, for Appletalk data packets,
* but used 0x000000 and an Ethernet
* packet type for AARP packets.
*/
ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
if (ret)
return (ret);
}
break;
case OUI_CISCO:
switch (et) {
case PID_CISCO_CDP:
cdp_print(ndo, p, length);
return (1);
case PID_CISCO_DTP:
dtp_print(ndo, p, length);
return (1);
case PID_CISCO_UDLD:
udld_print(ndo, p, length);
return (1);
case PID_CISCO_VTP:
vtp_print(ndo, p, length);
return (1);
case PID_CISCO_PVST:
case PID_CISCO_VLANBRIDGE:
stp_print(ndo, p, length);
return (1);
default:
break;
}
break;
case OUI_RFC2684:
switch (et) {
case PID_RFC2684_ETH_FCS:
case PID_RFC2684_ETH_NOFCS:
/*
* XXX - remove the last two bytes for
* PID_RFC2684_ETH_FCS?
*/
/*
* Skip the padding.
*/
ND_TCHECK_LEN(p, bridge_pad);
caplen -= bridge_pad;
length -= bridge_pad;
p += bridge_pad;
/*
* What remains is an Ethernet packet.
*/
ether_print(ndo, p, length, caplen, NULL, NULL);
return (1);
case PID_RFC2684_802_5_FCS:
case PID_RFC2684_802_5_NOFCS:
/*
* XXX - remove the last two bytes for
* PID_RFC2684_ETH_FCS?
*/
/*
* Skip the padding, but not the Access
* Control field.
*/
ND_TCHECK_LEN(p, bridge_pad);
caplen -= bridge_pad;
length -= bridge_pad;
p += bridge_pad;
/*
* What remains is an 802.5 Token Ring
* packet.
*/
token_print(ndo, p, length, caplen);
return (1);
case PID_RFC2684_FDDI_FCS:
case PID_RFC2684_FDDI_NOFCS:
/*
* XXX - remove the last two bytes for
* PID_RFC2684_ETH_FCS?
*/
/*
* Skip the padding.
*/
ND_TCHECK_LEN(p, bridge_pad + 1);
caplen -= bridge_pad + 1;
length -= bridge_pad + 1;
p += bridge_pad + 1;
/*
* What remains is an FDDI packet.
*/
fddi_print(ndo, p, length, caplen);
return (1);
case PID_RFC2684_BPDU:
stp_print(ndo, p, length);
return (1);
}
}
if (!ndo->ndo_eflag) {
/*
* Nobody printed the link-layer addresses, so print them, if
* we have any.
*/
if (src != NULL && dst != NULL) {
ND_PRINT("%s > %s ",
(src->addr_string)(ndo, src->addr),
(dst->addr_string)(ndo, dst->addr));
}
/*
* Print the SNAP header, but if the OUI is 000000, don't
* bother printing it, and report the PID as being an
* ethertype.
*/
if (orgcode == 0x000000) {
ND_PRINT("SNAP, ethertype %s (0x%04x), length %u: ",
tok2str(ethertype_values, "Unknown", et),
et, length);
} else {
ND_PRINT("SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
tok2str(oui_values, "Unknown", orgcode),
orgcode,
tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
et, length);
}
}
return (0);
