print-llc.c

TCPDUMP的C语言源代码,是在数据链路层的应用

/*
 * 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
 */

#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/tcpdump/print-llc.c,v 1.75 2007-04-13 09:43:11 hannes Exp $";
#endif

#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"			/* must come after interface.h */

#include "llc.h"
#include "ethertype.h"
#include "oui.h"

static 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 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" },
	{ 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 {
	u_int32_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 }
};

/*
 * Returns non-zero IFF it succeeds in printing the header
 */
int
llc_print(const u_char *p, u_int length, u_int caplen,
	  const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
{
	u_int8_t dsap_field, dsap, ssap_field, ssap;
	u_int16_t control;
	int is_u;
	register int ret;

	*extracted_ethertype = 0;

	if (caplen < 3) {
		(void)printf("[|llc]");
		default_print((u_char *)p, caplen);
		return(0);
	}

	dsap_field = *p;
	ssap_field = *(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 = *(p + 2);
	if ((control & LLC_U_FMT) == LLC_U_FMT) {
		/*
		 * U frame.
		 */
		is_u = 1;
	} else {
		/*
		 * The control field in I and S frames is
		 * 2 bytes...
		 */
		if (caplen < 4) {
			(void)printf("[|llc]");
			default_print((u_char *)p, caplen);
			return(0);
		}

		/*
		 * ...and is little-endian.
		 */
		control = EXTRACT_LE_16BITS(p + 2);
		is_u = 0;
	}

	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 <= ETHERMTU, 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 (eflag)
		printf("IPX 802.3: ");

            ipx_print(p, length);
            return (1);
	}

	dsap = dsap_field & ~LLC_IG;
	ssap = ssap_field & ~LLC_GSAP;

	if (eflag) {
                printf("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) {
			printf(", ctrl 0x%02x: ", control);
		} else {
			printf(", ctrl 0x%04x: ", control);
		}
	}

	if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
	    control == LLC_UI) {
		stp_print(p+3, length-3);
		return (1);
	}

	if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
	    control == LLC_UI) {
		ip_print(gndo, p+4, length-4);
		return (1);
	}

	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.
		 *
		 * Skip DSAP, LSAP, and control field.
		 */
                if (eflag)
                        printf("IPX 802.2: ");

		ipx_print(p+3, length-3);
		return (1);
	}

#ifdef TCPDUMP_DO_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).
		 */

		/*
		 * Skip the LLC header.
		 */
		if (is_u) {
			p += 3;
			length -= 3;
			caplen -= 3;
		} else {
			p += 4;
			length -= 4;
			caplen -= 4;
		}
		netbeui_print(control, p, length);
		return (1);
	}
#endif
	if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
	    && control == LLC_UI) {
		isoclns_print(p + 3, length - 3, caplen - 3);
		return (1);
	}

	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?
		 */
		ret = snap_print(p+3, length-3, caplen-3, extracted_ethertype,
		    2);
		if (ret)
			return (ret);
	}

	if (!eflag) {
		if (ssap == dsap) {
			if (esrc == NULL || edst == NULL)
				(void)printf("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
			else
				(void)printf("%s > %s %s ",
						etheraddr_string(esrc),
						etheraddr_string(edst),
						tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
		} else {
			if (esrc == NULL || edst == NULL)
				(void)printf("%s > %s ",
                                        tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
					tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
			else
				(void)printf("%s %s > %s %s ",
					etheraddr_string(esrc),
                                        tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
					etheraddr_string(edst),
					tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
		}
	}

	if (is_u) {
		printf("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);

		p += 3;
		length -= 3;
		caplen -= 3;

		if ((control & ~LLC_U_POLL) == LLC_XID) {
			if (*p == LLC_XID_FI) {
				printf(": %02x %02x", p[1], p[2]);
				p += 3;
				length -= 3;
				caplen -= 3;
			}
		}
	} else {
		if ((control & LLC_S_FMT) == LLC_S_FMT) {
			(void)printf("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);
		} else {
			(void)printf("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);
		}
		p += 4;
		length -= 4;
		caplen -= 4;
	}
	return(1);
}

int
snap_print(const u_char *p, u_int length, u_int caplen,
    u_short *extracted_ethertype, u_int bridge_pad)
{
	u_int32_t orgcode;
	register u_short et;
	register int ret;

	TCHECK2(*p, 5);
	orgcode = EXTRACT_24BITS(p);
	et = EXTRACT_16BITS(p + 3);

	if (eflag) {
		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;
			}
		}
		(void)printf("oui %s (0x%06x), %s %s (0x%04x): ",
		     tok2str(oui_values, "Unknown", orgcode),
		     orgcode,
		     (orgcode == 0x000000 ? "ethertype" : "pid"),
		     tok2str(tok, "Unknown", et),
		     et);
	}
	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 = ether_encap_print(et, p, length, caplen,
		    extracted_ethertype);
		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 = ether_encap_print(et, p, length, caplen,
			    extracted_ethertype);
			if (ret)
				return (ret);
		}
		break;

	case OUI_CISCO:
                switch (et) {
                case PID_CISCO_CDP:
                        cdp_print(p, length, caplen);
                        return (1);
                case PID_CISCO_DTP:
                        dtp_print(p, length); 
                        return (1);
                case PID_CISCO_UDLD:
                        udld_print(p, length);
                        return (1);
                case PID_CISCO_VTP:
                        vtp_print(p, length);
                        return (1);
                case PID_CISCO_PVST:
                        stp_print(p, length);
                        return (1);
                default:
                        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.
			 */
			TCHECK2(*p, bridge_pad);
			caplen -= bridge_pad;
			length -= bridge_pad;
			p += bridge_pad;

			/*
			 * What remains is an Ethernet packet.
			 */
			ether_print(p, length, caplen);
			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.
			 */
			TCHECK2(*p, bridge_pad);
			caplen -= bridge_pad;
			length -= bridge_pad;
			p += bridge_pad;

			/*
			 * What remains is an 802.5 Token Ring
			 * packet.
			 */
			token_print(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.
			 */
			TCHECK2(*p, bridge_pad + 1);
			caplen -= bridge_pad + 1;
			length -= bridge_pad + 1;
			p += bridge_pad + 1;

			/*
			 * What remains is an FDDI packet.
			 */
			fddi_print(p, length, caplen);
			return (1);

		case PID_RFC2684_BPDU:
			stp_print(p, length);
			return (1);
		}
	}
	return (0);

trunc:
	(void)printf("[|snap]");
	return (1);
}


/*
 * Local Variables:
 * c-style: whitesmith
 * c-basic-offset: 8
 * End:
 */