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tcpdump/print-llc.c
Francois-Xavier Le Bail 0c93b15d38 Rework "Update more link-layer dissectors to void functions" 
It's a follow-up to commit 81dbf4a0b0.

There is no need to update ether_print(), ether_common_print() and
ether_switch_tag_print() to void functions: back to u_int functions.

There is also no need to add a flag parameter to ether_print(),
ether_common_print() and ether_switch_tag_print(): Remove it.
2020-08-06 22:36:16 +02:00

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/*
* 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
*/
/* \summary: IEEE 802.2 LLC printer */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-stdinc.h"
#include "netdissect.h"
#include "addrtoname.h"
#include "extract.h"
#include "llc.h"
#include "ethertype.h"
#include "oui.h"
static const struct tok llc_values[] = {
{ LLCSAP_NULL, "Null" },
{ LLCSAP_GLOBAL, "Global" },
{ LLCSAP_8021B_I, "802.1B I" },
{ LLCSAP_8021B_G, "802.1B G" },
{ LLCSAP_IP, "IP" },
{ LLCSAP_SNA, "SNA" },
{ LLCSAP_PROWAYNM, "ProWay NM" },
{ LLCSAP_8021D, "STP" },
{ LLCSAP_RS511, "RS511" },
{ LLCSAP_ISO8208, "ISO8208" },
{ LLCSAP_PROWAY, "ProWay" },
{ LLCSAP_SNAP, "SNAP" },
{ LLCSAP_IPX, "IPX" },
{ LLCSAP_NETBEUI, "NetBeui" },
{ LLCSAP_ISONS, "OSI" },
{ 0, NULL },
};
static const struct tok llc_cmd_values[] = {
{ LLC_UI, "ui" },
{ LLC_TEST, "test" },
{ LLC_XID, "xid" },
{ LLC_UA, "ua" },
{ LLC_DISC, "disc" },
{ LLC_DM, "dm" },
{ LLC_SABME, "sabme" },
{ LLC_FRMR, "frmr" },
{ 0, NULL }
};
static const struct tok llc_flag_values[] = {
{ 0, "Command" },
{ LLC_GSAP, "Response" },
{ LLC_U_POLL, "Poll" },
{ LLC_GSAP|LLC_U_POLL, "Final" },
{ LLC_IS_POLL, "Poll" },
{ LLC_GSAP|LLC_IS_POLL, "Final" },
{ 0, NULL }
};
static const struct tok llc_ig_flag_values[] = {
{ 0, "Individual" },
{ LLC_IG, "Group" },
{ 0, NULL }
};
static const struct tok llc_supervisory_values[] = {
{ 0, "Receiver Ready" },
{ 1, "Receiver not Ready" },
{ 2, "Reject" },
{ 0, NULL }
};
static const struct tok cisco_values[] = {
{ PID_CISCO_CDP, "CDP" },
{ PID_CISCO_VTP, "VTP" },
{ PID_CISCO_DTP, "DTP" },
{ PID_CISCO_UDLD, "UDLD" },
{ PID_CISCO_PVST, "PVST" },
{ PID_CISCO_VLANBRIDGE, "VLAN Bridge" },
{ 0, NULL }
};
static const struct tok bridged_values[] = {
{ PID_RFC2684_ETH_FCS, "Ethernet + FCS" },
{ PID_RFC2684_ETH_NOFCS, "Ethernet w/o FCS" },
{ PID_RFC2684_802_4_FCS, "802.4 + FCS" },
{ PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" },
{ PID_RFC2684_802_5_FCS, "Token Ring + FCS" },
{ PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" },
{ PID_RFC2684_FDDI_FCS, "FDDI + FCS" },
{ PID_RFC2684_FDDI_NOFCS, "FDDI w/o FCS" },
{ PID_RFC2684_802_6_FCS, "802.6 + FCS" },
{ PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" },
{ PID_RFC2684_BPDU, "BPDU" },
{ 0, NULL },
};
static const struct tok null_values[] = {
{ 0, NULL }
};
struct oui_tok {
uint32_t oui;
const struct tok *tok;
};
static const struct oui_tok oui_to_tok[] = {
{ OUI_ENCAP_ETHER, ethertype_values },
{ OUI_CISCO_90, ethertype_values }, /* uses some Ethertype values */
{ OUI_APPLETALK, ethertype_values }, /* uses some Ethertype values */
{ OUI_CISCO, cisco_values },
{ OUI_RFC2684, bridged_values }, /* bridged, RFC 2427 FR or RFC 2864 ATM */
{ 0, NULL }
};
/*
* 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;
ndo->ndo_protocol = "llc";
if (caplen < 3) {
nd_print_trunc(ndo);
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (caplen);
}
if (length < 3) {
nd_print_trunc(ndo);
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (length);
}
dsap_field = GET_U_1(p);
ssap_field = GET_U_1(p + 1);
/*
* 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 (ndo->ndo_eflag)
ND_PRINT("IPX 802.3: ");
ipx_print(ndo, p, length);
return (0); /* no LLC header */
}
dsap = dsap_field & ~LLC_IG;
ssap = ssap_field & ~LLC_GSAP;
if (ndo->ndo_eflag) {
ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
tok2str(llc_values, "Unknown", dsap),
dsap,
tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
tok2str(llc_values, "Unknown", ssap),
ssap,
tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
if (is_u) {
ND_PRINT(", ctrl 0x%02x: ", control);
} else {
ND_PRINT(", ctrl 0x%04x: ", control);
}
}
/*
* Skip LLC header.
*/
p += hdrlen;
length -= hdrlen;
caplen -= hdrlen;
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) {
if (ssap == dsap) {
if (src == NULL || dst == NULL)
ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
else
ND_PRINT("%s > %s %s ",
(src->addr_string)(ndo, src->addr),
(dst->addr_string)(ndo, dst->addr),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
} else {
if (src == NULL || dst == NULL)
ND_PRINT("%s > %s ",
tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
else
ND_PRINT("%s %s > %s %s ",
(src->addr_string)(ndo, src->addr),
tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
(dst->addr_string)(ndo, dst->addr),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
}
}
if (is_u) {
ND_PRINT("Unnumbered, %s, Flags [%s], length %u",
tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
length + hdrlen);
if ((control & ~LLC_U_POLL) == LLC_XID) {
if (length == 0) {
/*
* XID with no payload.
* This could, for example, be an SNA
* "short form" XID.
*/
return (hdrlen);
}
if (caplen < 1) {
nd_print_trunc(ndo);
if (caplen > 0)
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (hdrlen);
}
if (GET_U_1(p) == LLC_XID_FI) {
if (caplen < 3 || length < 3) {
nd_print_trunc(ndo);
if (caplen > 0)
ND_DEFAULTPRINT((const u_char *)p, caplen);
} else
ND_PRINT(": %02x %02x",
GET_U_1(p + 1),
GET_U_1(p + 2));
return (hdrlen);
}
}
} else {
if ((control & LLC_S_FMT) == LLC_S_FMT) {
ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
LLC_IS_NR(control),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
length + hdrlen);
return (hdrlen); /* no payload to print */
} else {
ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
LLC_I_NS(control),
LLC_IS_NR(control),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
length + hdrlen);
}
}
return (-hdrlen);
}
static const struct tok *
oui_to_struct_tok(uint32_t orgcode)
{
const struct tok *tok = null_values;
const struct oui_tok *otp;
for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
if (otp->oui == orgcode) {
tok = otp->tok;
break;
}
}
return (tok);
}
int
snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
const struct lladdr_info *src, const struct lladdr_info *dst,
u_int bridge_pad)
{
uint32_t orgcode;
u_short et;
int ret;
ndo->ndo_protocol = "snap";
ND_TCHECK_5(p);
if (caplen < 5 || length < 5)
goto trunc;
orgcode = GET_BE_U_3(p);
et = GET_BE_U_2(p + 3);
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, caplen);
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);
trunc:
nd_print_trunc(ndo);
return (1);
}
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