print-isoclns.c

TCPDUMP的C语言源代码,是在数据链路层的应用

trunctlv:
    printf("%spacket exceeded snapshot",ident);
    return(0);
}


/*
 * this is the common IS-REACH decoder it is called
 * from various EXTD-IS REACH style TLVs (22,24,222)
 */

static int
isis_print_ext_is_reach (const u_int8_t *tptr,const char *ident, int tlv_type) {

    char ident_buffer[20];
    int subtlv_type,subtlv_len,subtlv_sum_len;
    int proc_bytes = 0; /* how many bytes did we process ? */
    
    if (!TTEST2(*tptr, NODE_ID_LEN))
        return(0);

    printf("%sIS Neighbor: %s", ident, isis_print_id(tptr, NODE_ID_LEN));
    tptr+=(NODE_ID_LEN);

    if (tlv_type != ISIS_TLV_IS_ALIAS_ID) { /* the Alias TLV Metric field is implicit 0 */
        if (!TTEST2(*tptr, 3))    /* and is therefore skipped */
	    return(0);
	printf(", Metric: %d",EXTRACT_24BITS(tptr));
	tptr+=3;
    }
        
    if (!TTEST2(*tptr, 1))
        return(0);
    subtlv_sum_len=*(tptr++); /* read out subTLV length */
    proc_bytes=NODE_ID_LEN+3+1;
    printf(", %ssub-TLVs present",subtlv_sum_len ? "" : "no ");
    if (subtlv_sum_len) {
        printf(" (%u)",subtlv_sum_len);
        while (subtlv_sum_len>0) {
            if (!TTEST2(*tptr,2))
                return(0);
            subtlv_type=*(tptr++);
            subtlv_len=*(tptr++);
            /* prepend the ident string */
            snprintf(ident_buffer, sizeof(ident_buffer), "%s  ",ident);
            if(!isis_print_is_reach_subtlv(tptr,subtlv_type,subtlv_len,ident_buffer))
                return(0);
            tptr+=subtlv_len;
            subtlv_sum_len-=(subtlv_len+2);
            proc_bytes+=(subtlv_len+2);
        }
    }
    return(proc_bytes);
}

/*
 * this is the common Multi Topology ID decoder
 * it is called from various MT-TLVs (222,229,235,237)
 */

static int
isis_print_mtid (const u_int8_t *tptr,const char *ident) {
    
    if (!TTEST2(*tptr, 2))
        return(0);

    printf("%s%s",
           ident,
           tok2str(isis_mt_values,
                   "Reserved for IETF Consensus",
                   ISIS_MASK_MTID(EXTRACT_16BITS(tptr))));

    printf(" Topology (0x%03x), Flags: [%s]",
           ISIS_MASK_MTID(EXTRACT_16BITS(tptr)),
           bittok2str(isis_mt_flag_values, "none",ISIS_MASK_MTFLAGS(EXTRACT_16BITS(tptr))));

    return(2);
}

/*
 * this is the common extended IP reach decoder
 * it is called from TLVs (135,235,236,237)
 * we process the TLV and optional subTLVs and return
 * the amount of processed bytes
 */

static int
isis_print_extd_ip_reach (const u_int8_t *tptr, const char *ident, u_int16_t afi) {

    char ident_buffer[20];
#ifdef INET6
    u_int8_t prefix[sizeof(struct in6_addr)]; /* shared copy buffer for IPv4 and IPv6 prefixes */
#else
    u_int8_t prefix[sizeof(struct in_addr)]; /* shared copy buffer for IPv4 prefixes */
#endif
    u_int metric, status_byte, bit_length, byte_length, sublen, processed, subtlvtype, subtlvlen;

    if (!TTEST2(*tptr, 4))
        return (0);
    metric = EXTRACT_32BITS(tptr);
    processed=4;
    tptr+=4;
    
    if (afi == AF_INET) {
        if (!TTEST2(*tptr, 1)) /* fetch status byte */
            return (0);
        status_byte=*(tptr++);
        bit_length = status_byte&0x3f;
        if (bit_length > 32) {
            printf("%sIPv4 prefix: bad bit length %u",
                   ident,
                   bit_length);
            return (0);
        }
        processed++;
#ifdef INET6
    } else if (afi == AF_INET6) {
        if (!TTEST2(*tptr, 1)) /* fetch status & prefix_len byte */
            return (0);
        status_byte=*(tptr++);
        bit_length=*(tptr++);
        if (bit_length > 128) {
            printf("%sIPv6 prefix: bad bit length %u",
                   ident,
                   bit_length);
            return (0);
        }
        processed+=2;
#endif
    } else
        return (0); /* somebody is fooling us */

    byte_length = (bit_length + 7) / 8; /* prefix has variable length encoding */
   
    if (!TTEST2(*tptr, byte_length))
        return (0);
    memset(prefix, 0, sizeof prefix);   /* clear the copy buffer */
    memcpy(prefix,tptr,byte_length);    /* copy as much as is stored in the TLV */
    tptr+=byte_length;
    processed+=byte_length;

    if (afi == AF_INET)
        printf("%sIPv4 prefix: %15s/%u",
               ident,
               ipaddr_string(prefix),
               bit_length);
#ifdef INET6
    if (afi == AF_INET6)
        printf("%sIPv6 prefix: %s/%u",
               ident,
               ip6addr_string(prefix),
               bit_length);
#endif 
   
    printf(", Distribution: %s, Metric: %u",
           ISIS_MASK_TLV_EXTD_IP_UPDOWN(status_byte) ? "down" : "up",
           metric);

    if (afi == AF_INET && ISIS_MASK_TLV_EXTD_IP_SUBTLV(status_byte))
        printf(", sub-TLVs present");
#ifdef INET6
    if (afi == AF_INET6)
        printf(", %s%s",
               ISIS_MASK_TLV_EXTD_IP6_IE(status_byte) ? "External" : "Internal",
               ISIS_MASK_TLV_EXTD_IP6_SUBTLV(status_byte) ? ", sub-TLVs present" : "");
#endif
    
    if ((afi == AF_INET  && ISIS_MASK_TLV_EXTD_IP_SUBTLV(status_byte))
#ifdef INET6
     || (afi == AF_INET6 && ISIS_MASK_TLV_EXTD_IP6_SUBTLV(status_byte))
#endif
	) {
        /* assume that one prefix can hold more
           than one subTLV - therefore the first byte must reflect
           the aggregate bytecount of the subTLVs for this prefix
        */
        if (!TTEST2(*tptr, 1))
            return (0);
        sublen=*(tptr++);
        processed+=sublen+1;
        printf(" (%u)",sublen);   /* print out subTLV length */
        
        while (sublen>0) {
            if (!TTEST2(*tptr,2))
                return (0);
            subtlvtype=*(tptr++);
            subtlvlen=*(tptr++);
            /* prepend the ident string */
            snprintf(ident_buffer, sizeof(ident_buffer), "%s  ",ident);
            if(!isis_print_ip_reach_subtlv(tptr,subtlvtype,subtlvlen,ident_buffer))
                return(0);
            tptr+=subtlvlen;
            sublen-=(subtlvlen+2);
        }
    }
    return (processed);
}

/*
 * isis_print
 * Decode IS-IS packets.  Return 0 on error.
 */

static int isis_print (const u_int8_t *p, u_int length)
{
    const struct isis_common_header *isis_header;

    const struct isis_iih_lan_header *header_iih_lan;
    const struct isis_iih_ptp_header *header_iih_ptp;
    const struct isis_lsp_header *header_lsp;
    const struct isis_csnp_header *header_csnp;
    const struct isis_psnp_header *header_psnp;

    const struct isis_tlv_lsp *tlv_lsp;
    const struct isis_tlv_ptp_adj *tlv_ptp_adj;
    const struct isis_tlv_is_reach *tlv_is_reach;
    const struct isis_tlv_es_reach *tlv_es_reach;

    u_int8_t pdu_type, max_area, id_length, tlv_type, tlv_len, tmp, alen, lan_alen, prefix_len;
    u_int8_t ext_is_len, ext_ip_len, mt_len;
    const u_int8_t *optr, *pptr, *tptr;
    u_short packet_len,pdu_len;
    u_int i,vendor_id;

    packet_len=length;
    optr = p; /* initialize the _o_riginal pointer to the packet start -
                 need it for parsing the checksum TLV */
    isis_header = (const struct isis_common_header *)p;
    TCHECK(*isis_header);
    pptr = p+(ISIS_COMMON_HEADER_SIZE);
    header_iih_lan = (const struct isis_iih_lan_header *)pptr;
    header_iih_ptp = (const struct isis_iih_ptp_header *)pptr;
    header_lsp = (const struct isis_lsp_header *)pptr;
    header_csnp = (const struct isis_csnp_header *)pptr;
    header_psnp = (const struct isis_psnp_header *)pptr;

    if (!eflag)
        printf("IS-IS");

    /*
     * Sanity checking of the header.
     */

    if (isis_header->version != ISIS_VERSION) {
	printf("version %d packet not supported", isis_header->version);
	return (0);
    }

    if ((isis_header->id_length != SYSTEM_ID_LEN) && (isis_header->id_length != 0)) {
	printf("system ID length of %d is not supported",
	       isis_header->id_length);
	return (0);
    }

    if (isis_header->pdu_version != ISIS_VERSION) {
	printf("version %d packet not supported", isis_header->pdu_version);
	return (0);
    }

    max_area = isis_header->max_area;
    switch(max_area) {
    case 0:
	max_area = 3;	 /* silly shit */
	break;
    case 255:
	printf("bad packet -- 255 areas");
	return (0);
    default:
	break;
    }

    id_length = isis_header->id_length;
    switch(id_length) {
    case 0:
        id_length = 6;	 /* silly shit again */
	break;
    case 1:              /* 1-8 are valid sys-ID lenghts */
    case 2:
    case 3:
    case 4:
    case 5:
    case 6:
    case 7:
    case 8:
        break;
    case 255:
        id_length = 0;   /* entirely useless */
	break;
    default:
        break;
    }

    /* toss any non 6-byte sys-ID len PDUs */
    if (id_length != 6 ) { 
	printf("bad packet -- illegal sys-ID length (%u)", id_length);
	return (0);
    }

    pdu_type=isis_header->pdu_type;

    /* in non-verbose mode print the basic PDU Type plus PDU specific brief information*/
    if (vflag < 1) {
        printf("%s%s",
               eflag ? "" : ", ",
               tok2str(isis_pdu_values,"unknown PDU-Type %u",pdu_type));

	switch (pdu_type) {

	case ISIS_PDU_L1_LAN_IIH:
	case ISIS_PDU_L2_LAN_IIH:
	    printf(", src-id %s",
                   isis_print_id(header_iih_lan->source_id,SYSTEM_ID_LEN));
	    printf(", lan-id %s, prio %u",
                   isis_print_id(header_iih_lan->lan_id,NODE_ID_LEN),
                   header_iih_lan->priority);
	    break;
	case ISIS_PDU_PTP_IIH:
	    printf(", src-id %s", isis_print_id(header_iih_ptp->source_id,SYSTEM_ID_LEN));
	    break;
	case ISIS_PDU_L1_LSP:
	case ISIS_PDU_L2_LSP:
	    printf(", lsp-id %s, seq 0x%08x, lifetime %5us",
		   isis_print_id(header_lsp->lsp_id, LSP_ID_LEN),
		   EXTRACT_32BITS(header_lsp->sequence_number),
		   EXTRACT_16BITS(header_lsp->remaining_lifetime));
	    break;
	case ISIS_PDU_L1_CSNP:
	case ISIS_PDU_L2_CSNP:
	    printf(", src-id %s", isis_print_id(header_csnp->source_id,NODE_ID_LEN));
	    break;
	case ISIS_PDU_L1_PSNP:
	case ISIS_PDU_L2_PSNP:
	    printf(", src-id %s", isis_print_id(header_psnp->source_id,NODE_ID_LEN));
	    break;

	}
	printf(", length %u", length);

        return(1);
    }

    /* ok they seem to want to know everything - lets fully decode it */
    printf("%slength %u", eflag ? "" : ", ",length);

    printf("\n\t%s, hlen: %u, v: %u, pdu-v: %u, sys-id-len: %u (%u), max-area: %u (%u)",
           tok2str(isis_pdu_values,
                   "unknown, type %u",
                   pdu_type),
           isis_header->fixed_len,
           isis_header->version,
           isis_header->pdu_version,
	   id_length,
	   isis_header->id_length,
           max_area,
           isis_header->max_area);

    if (vflag > 1) {
        if(!print_unknown_data(optr,"\n\t",8)) /* provide the _o_riginal pointer */
            return(0);                         /* for optionally debugging the common header */
    }

    switch (pdu_type) {

    case ISIS_PDU_L1_LAN_IIH:
    case ISIS_PDU_L2_LAN_IIH:
	if (isis_header->fixed_len != (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_LAN_HEADER_SIZE)) {
	    printf(", bogus fixed header length %u should be %lu",
		   isis_header->fixed_len, (unsigned long)ISIS_IIH_LAN_HEADER_SIZE);
	    return (0);
	}

	pdu_len=EXTRACT_16BITS(header_iih_lan->pdu_len);
	if (packet_len>pdu_len) {
            packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
            length=pdu_len;
	}

	TCHECK(*header_iih_lan);
	printf("\n\t  source-id: %s,  holding time: %us, Flags: [%s]",
               isis_print_id(header_iih_lan->source_id,SYSTEM_ID_LEN),
               EXTRACT_16BITS(header_iih_lan->holding_time),
               tok2str(isis_iih_circuit_type_values,
                       "unknown circuit type 0x%02x",
                       header_iih_lan->circuit_type));

	printf("\n\t  lan-id:    %s