print-fr.c

来自「TCPDUMP的C语言源代码,是在数据链路层的应用」· C语言 代码 · 共 885 行 · 第 1/2 页

/*
 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
 *	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.
 */

#ifndef lint
static const char rcsid[] _U_ =
	"@(#)$Header: /tcpdump/master/tcpdump/print-fr.c,v 1.51 2006-06-23 22:20:32 hannes Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <string.h>
#include <pcap.h>

#include "addrtoname.h"
#include "interface.h"
#include "ethertype.h"
#include "nlpid.h"
#include "extract.h"
#include "oui.h"

static void frf15_print(const u_char *, u_int);

/*
 * the frame relay header has a variable length
 *
 * the EA bit determines if there is another byte
 * in the header
 *
 * minimum header length is 2 bytes
 * maximum header length is 4 bytes
 *
 *      7    6    5    4    3    2    1    0
 *    +----+----+----+----+----+----+----+----+
 *    |        DLCI (6 bits)        | CR | EA |
 *    +----+----+----+----+----+----+----+----+
 *    |   DLCI (4 bits)   |FECN|BECN| DE | EA |
 *    +----+----+----+----+----+----+----+----+
 *    |           DLCI (7 bits)          | EA |
 *    +----+----+----+----+----+----+----+----+
 *    |        DLCI (6 bits)        |SDLC| EA |
 *    +----+----+----+----+----+----+----+----+
 */

#define FR_EA_BIT	0x01

#define FR_CR_BIT       0x02000000
#define FR_DE_BIT	0x00020000
#define FR_BECN_BIT	0x00040000
#define FR_FECN_BIT	0x00080000
#define FR_SDLC_BIT	0x00000002


struct tok fr_header_flag_values[] = {
    { FR_CR_BIT, "C!" },
    { FR_DE_BIT, "DE" },
    { FR_BECN_BIT, "BECN" },
    { FR_FECN_BIT, "FECN" },
    { FR_SDLC_BIT, "sdlcore" },
    { 0, NULL }
};

/* FRF.15 / FRF.16 */
#define MFR_B_BIT 0x80
#define MFR_E_BIT 0x40
#define MFR_C_BIT 0x20
#define MFR_BEC_MASK    (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
#define MFR_CTRL_FRAME  (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
#define MFR_FRAG_FRAME  (MFR_B_BIT | MFR_E_BIT )

struct tok frf_flag_values[] = {
    { MFR_B_BIT, "Begin" },
    { MFR_E_BIT, "End" },
    { MFR_C_BIT, "Control" },
    { 0, NULL }
};

/* Finds out Q.922 address length, DLCI and flags. Returns 0 on success
 * save the flags dep. on address length
 */
static int parse_q922_addr(const u_char *p, u_int *dlci,
                           u_int *addr_len, u_int8_t *flags)
{
	if ((p[0] & FR_EA_BIT))
		return -1;

	*addr_len = 2;
	*dlci = ((p[0] & 0xFC) << 2) | ((p[1] & 0xF0) >> 4);

        flags[0] = p[0] & 0x02; /* populate the first flag fields */
        flags[1] = p[1] & 0x0c;
        flags[2] = 0;           /* clear the rest of the flags */
        flags[3] = 0;

	if (p[1] & FR_EA_BIT)
		return 0;	/* 2-byte Q.922 address */

	p += 2;
	(*addr_len)++;		/* 3- or 4-byte Q.922 address */
	if ((p[0] & FR_EA_BIT) == 0) {
		*dlci = (*dlci << 7) | (p[0] >> 1);
		(*addr_len)++;	/* 4-byte Q.922 address */
		p++;
	}

	if ((p[0] & FR_EA_BIT) == 0)
		return -1; /* more than 4 bytes of Q.922 address? */

        flags[3] = p[0] & 0x02;

        *dlci = (*dlci << 6) | (p[0] >> 2);

	return 0;
}

char *q922_string(const u_char *p) {

    static u_int dlci, addr_len;
    static u_int8_t flags[4];
    static char buffer[sizeof("DLCI xxxxxxxxxx")];
    memset(buffer, 0, sizeof(buffer));

    if (parse_q922_addr(p, &dlci, &addr_len, flags) == 0){
        snprintf(buffer, sizeof(buffer), "DLCI %u", dlci);
    }

    return buffer;
}


/* Frame Relay packet structure, with flags and CRC removed

                  +---------------------------+
                  |       Q.922 Address*      |
                  +--                       --+
                  |                           |
                  +---------------------------+
                  | Control (UI = 0x03)       |
                  +---------------------------+
                  | Optional Pad      (0x00)  |
                  +---------------------------+
                  | NLPID                     |
                  +---------------------------+
                  |             .             |
                  |             .             |
                  |             .             |
                  |           Data            |
                  |             .             |
                  |             .             |
                  +---------------------------+

           * Q.922 addresses, as presently defined, are two octets and
             contain a 10-bit DLCI.  In some networks Q.922 addresses
             may optionally be increased to three or four octets.
*/

static u_int
fr_hdrlen(const u_char *p, u_int addr_len)
{
	if (!p[addr_len + 1] /* pad exist */)
		return addr_len + 1 /* UI */ + 1 /* pad */ + 1 /* NLPID */;
	else 
		return addr_len + 1 /* UI */ + 1 /* NLPID */;
}

static void
fr_hdr_print(int length, u_int addr_len, u_int dlci, u_int8_t *flags, u_int16_t nlpid)
{
    if (qflag) {
        (void)printf("Q.922, DLCI %u, length %u: ",
                     dlci,
                     length);
    } else {
        if (nlpid <= 0xff) /* if its smaller than 256 then its a NLPID */
            (void)printf("Q.922, hdr-len %u, DLCI %u, Flags [%s], NLPID %s (0x%02x), length %u: ",
                         addr_len,
                         dlci,
                         bittok2str(fr_header_flag_values, "none", EXTRACT_32BITS(flags)),
                         tok2str(nlpid_values,"unknown", nlpid),
                         nlpid,
                         length);
        else /* must be an ethertype */
            (void)printf("Q.922, hdr-len %u, DLCI %u, Flags [%s], cisco-ethertype %s (0x%04x), length %u: ",
                         addr_len,
                         dlci,
                         bittok2str(fr_header_flag_values, "none", EXTRACT_32BITS(flags)),
                         tok2str(ethertype_values, "unknown", nlpid),
                         nlpid,
                         length);        
    }
}

u_int
fr_if_print(const struct pcap_pkthdr *h, register const u_char *p)
{
	register u_int length = h->len;
	register u_int caplen = h->caplen;

        TCHECK2(*p, 4); /* minimum frame header length */

        if ((length = fr_print(p, length)) == 0)
            return (0);
        else
            return length;
 trunc:
        printf("[|fr]");
        return caplen;
}

u_int
fr_print(register const u_char *p, u_int length)
{
	u_int16_t extracted_ethertype;
	u_int dlci;
	u_int addr_len;
	u_int16_t nlpid;
	u_int hdr_len;
	u_int8_t flags[4];

	if (parse_q922_addr(p, &dlci, &addr_len, flags)) {
		printf("Q.922, invalid address");
		return 0;
	}

        TCHECK2(*p,addr_len+1+1);
	hdr_len = fr_hdrlen(p, addr_len);
        TCHECK2(*p,hdr_len);

	if (p[addr_len] != 0x03 && dlci != 0) {

                /* lets figure out if we have cisco style encapsulation: */
                extracted_ethertype = EXTRACT_16BITS(p+addr_len);

                if (eflag)
                    fr_hdr_print(length, addr_len, dlci, flags, extracted_ethertype);

                if (ether_encap_print(extracted_ethertype,
                                      p+addr_len+ETHERTYPE_LEN,
                                      length-addr_len-ETHERTYPE_LEN,
                                      length-addr_len-ETHERTYPE_LEN,
                                      &extracted_ethertype) == 0)
                    /* ether_type not known, probably it wasn't one */
                    printf("UI %02x! ", p[addr_len]);
                else
                    return hdr_len;
        }

	if (!p[addr_len + 1]) {	/* pad byte should be used with 3-byte Q.922 */
		if (addr_len != 3)
			printf("Pad! ");
	} else if (addr_len == 3)
		printf("No pad! ");

	nlpid = p[hdr_len - 1];

	if (eflag)
		fr_hdr_print(length, addr_len, dlci, flags, nlpid);
	p += hdr_len;
	length -= hdr_len;

	switch (nlpid) {
	case NLPID_IP:
	        ip_print(gndo, p, length);
		break;

#ifdef INET6
	case NLPID_IP6:
		ip6_print(p, length);
		break;
#endif
	case NLPID_CLNP:
	case NLPID_ESIS:
	case NLPID_ISIS:
                isoclns_print(p-1, length+1, length+1); /* OSI printers need the NLPID field */
		break;

	case NLPID_SNAP:
		if (snap_print(p, length, length, &extracted_ethertype, 0) == 0) {
			/* ether_type not known, print raw packet */
                        if (!eflag)
                            fr_hdr_print(length + hdr_len, hdr_len,
                                         dlci, flags, nlpid);
			if (!suppress_default_print)
                            default_print(p - hdr_len, length + hdr_len);
		}
		break;

        case NLPID_Q933:
		q933_print(p, length);
		break;

        case NLPID_MFR:
                frf15_print(p, length);
                break;

        case NLPID_PPP:
                ppp_print(p, length);
                break;

	default:
		if (!eflag)
                    fr_hdr_print(length + hdr_len, addr_len,
				     dlci, flags, nlpid);
		if (!xflag)
			default_print(p, length);
	}

	return hdr_len;

 trunc:
        printf("[|fr]");
        return 0;

}

u_int
mfr_if_print(const struct pcap_pkthdr *h, register const u_char *p)
{
	register u_int length = h->len;
	register u_int caplen = h->caplen;

        TCHECK2(*p, 2); /* minimum frame header length */

        if ((length = mfr_print(p, length)) == 0)
            return (0);
        else
            return length;
 trunc:
        printf("[|mfr]");
        return caplen;
}


#define MFR_CTRL_MSG_ADD_LINK        1
#define MFR_CTRL_MSG_ADD_LINK_ACK    2
#define MFR_CTRL_MSG_ADD_LINK_REJ    3
#define MFR_CTRL_MSG_HELLO           4
#define MFR_CTRL_MSG_HELLO_ACK       5
#define MFR_CTRL_MSG_REMOVE_LINK     6
#define MFR_CTRL_MSG_REMOVE_LINK_ACK 7

struct tok mfr_ctrl_msg_values[] = {
    { MFR_CTRL_MSG_ADD_LINK, "Add Link" },
    { MFR_CTRL_MSG_ADD_LINK_ACK, "Add Link ACK" },
    { MFR_CTRL_MSG_ADD_LINK_REJ, "Add Link Reject" },
    { MFR_CTRL_MSG_HELLO, "Hello" },
    { MFR_CTRL_MSG_HELLO_ACK, "Hello ACK" },
    { MFR_CTRL_MSG_REMOVE_LINK, "Remove Link" },
    { MFR_CTRL_MSG_REMOVE_LINK_ACK, "Remove Link ACK" },
    { 0, NULL }
};

#define MFR_CTRL_IE_BUNDLE_ID  1
#define MFR_CTRL_IE_LINK_ID    2
#define MFR_CTRL_IE_MAGIC_NUM  3
#define MFR_CTRL_IE_TIMESTAMP  5
#define MFR_CTRL_IE_VENDOR_EXT 6
#define MFR_CTRL_IE_CAUSE      7

struct tok mfr_ctrl_ie_values[] = {
    { MFR_CTRL_IE_BUNDLE_ID, "Bundle ID"},
    { MFR_CTRL_IE_LINK_ID, "Link ID"},
    { MFR_CTRL_IE_MAGIC_NUM, "Magic Number"},
    { MFR_CTRL_IE_TIMESTAMP, "Timestamp"},
    { MFR_CTRL_IE_VENDOR_EXT, "Vendor Extension"},
    { MFR_CTRL_IE_CAUSE, "Cause"},
    { 0, NULL }
};

#define MFR_ID_STRING_MAXLEN 50

struct ie_tlv_header_t {
    u_int8_t ie_type;
    u_int8_t ie_len;
};

u_int
mfr_print(register const u_char *p, u_int length)
{
    u_int tlen,idx,hdr_len = 0;
    u_int16_t sequence_num;
    u_int8_t ie_type,ie_len;
    const u_int8_t *tptr;


/*
 * FRF.16 Link Integrity Control Frame
 * 
 *      7    6    5    4    3    2    1    0
 *    +----+----+----+----+----+----+----+----+
 *    | B  | E  | C=1| 0    0    0    0  | EA |
 *    +----+----+----+----+----+----+----+----+
 *    | 0    0    0    0    0    0    0    0  |
 *    +----+----+----+----+----+----+----+----+
 *    |              message type             |
 *    +----+----+----+----+----+----+----+----+
 */

    TCHECK2(*p, 4); /* minimum frame header length */

    if ((p[0] & MFR_BEC_MASK) == MFR_CTRL_FRAME && p[1] == 0) {
        printf("FRF.16 Control, Flags [%s], %s, length %u",
               bittok2str(frf_flag_values,"none",(p[0] & MFR_BEC_MASK)),
               tok2str(mfr_ctrl_msg_values,"Unknown Message (0x%02x)",p[2]),
               length);
        tptr = p + 3;
        tlen = length -3;
        hdr_len = 3;

        if (!vflag)
            return hdr_len;

        while (tlen>sizeof(struct ie_tlv_header_t)) {
            TCHECK2(*tptr, sizeof(struct ie_tlv_header_t));
            ie_type=tptr[0];
            ie_len=tptr[1];

            printf("\n\tIE %s (%u), length %u: ",
                   tok2str(mfr_ctrl_ie_values,"Unknown",ie_type),
                   ie_type,
                   ie_len);