From Carles Kishimoto <[email protected]>:

[tcpdump] / print-llc.c

/*
 * 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 1.72 2007-03-19 15:14:14 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" },
        { 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_UDLD:
                        udld_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:
 */