Code: pgm_print(netdissect_options *ndo,
          register const u_char *bp, register u_int length,
          register const u_char *bp2)
{
	register const struct pgm_header *pgm;
	register const struct ip *ip;
	register char ch;
	uint16_t sport, dport;
	u_int nla_afnum;
	char nla_buf[INET6_ADDRSTRLEN];
	register const struct ip6_hdr *ip6;
	uint8_t opt_type, opt_len;
	uint32_t seq, opts_len, len, offset;

	pgm = (const struct pgm_header *)bp;
	ip = (const struct ip *)bp2;
	if (IP_V(ip) == 6)
		ip6 = (const struct ip6_hdr *)bp2;
	else
		ip6 = NULL;
	ch = '\0';
	if (!ND_TTEST(pgm->pgm_dport)) {
		if (ip6) {
 			ND_PRINT((ndo, "%s > %s: [|pgm]",
 				ip6addr_string(ndo, &ip6->ip6_src),
 				ip6addr_string(ndo, &ip6->ip6_dst)));
			return;
 		} else {
 			ND_PRINT((ndo, "%s > %s: [|pgm]",
 				ipaddr_string(ndo, &ip->ip_src),
 				ipaddr_string(ndo, &ip->ip_dst)));
			return;
 		}
 	}
 
 	sport = EXTRACT_16BITS(&pgm->pgm_sport);
	dport = EXTRACT_16BITS(&pgm->pgm_dport);

	if (ip6) {
		if (ip6->ip6_nxt == IPPROTO_PGM) {
			ND_PRINT((ndo, "%s.%s > %s.%s: ",
				ip6addr_string(ndo, &ip6->ip6_src),
				tcpport_string(ndo, sport),
				ip6addr_string(ndo, &ip6->ip6_dst),
				tcpport_string(ndo, dport)));
		} else {
			ND_PRINT((ndo, "%s > %s: ",
				tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
		}
	} else {
		if (ip->ip_p == IPPROTO_PGM) {
			ND_PRINT((ndo, "%s.%s > %s.%s: ",
				ipaddr_string(ndo, &ip->ip_src),
				tcpport_string(ndo, sport),
				ipaddr_string(ndo, &ip->ip_dst),
				tcpport_string(ndo, dport)));
		} else {
			ND_PRINT((ndo, "%s > %s: ",
				tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
		}
	}

	ND_TCHECK(*pgm);

        ND_PRINT((ndo, "PGM, length %u", EXTRACT_16BITS(&pgm->pgm_length)));

        if (!ndo->ndo_vflag)
            return;

	ND_PRINT((ndo, " 0x%02x%02x%02x%02x%02x%02x ",
		     pgm->pgm_gsid[0],
                     pgm->pgm_gsid[1],
                     pgm->pgm_gsid[2],
		     pgm->pgm_gsid[3],
                     pgm->pgm_gsid[4],
                     pgm->pgm_gsid[5]));
	switch (pgm->pgm_type) {
	case PGM_SPM: {
	    const struct pgm_spm *spm;

	    spm = (const struct pgm_spm *)(pgm + 1);
	    ND_TCHECK(*spm);
	    bp = (const u_char *) (spm + 1);

	    switch (EXTRACT_16BITS(&spm->pgms_nla_afi)) {
	    case AFNUM_INET:
		ND_TCHECK2(*bp, sizeof(struct in_addr));
		addrtostr(bp, nla_buf, sizeof(nla_buf));
		bp += sizeof(struct in_addr);
		break;
	    case AFNUM_INET6:
		ND_TCHECK2(*bp, sizeof(struct in6_addr));
		addrtostr6(bp, nla_buf, sizeof(nla_buf));
		bp += sizeof(struct in6_addr);
		break;
	    default:
		goto trunc;
		break;
	    }

	    ND_PRINT((ndo, "SPM seq %u trail %u lead %u nla %s",
			 EXTRACT_32BITS(&spm->pgms_seq),
                         EXTRACT_32BITS(&spm->pgms_trailseq),
			 EXTRACT_32BITS(&spm->pgms_leadseq),
                         nla_buf));
	    break;
	}

	case PGM_POLL: {
	    const struct pgm_poll *poll_msg;

	    poll_msg = (const struct pgm_poll *)(pgm + 1);
	    ND_TCHECK(*poll_msg);
	    ND_PRINT((ndo, "POLL seq %u round %u",
			 EXTRACT_32BITS(&poll_msg->pgmp_seq),
                         EXTRACT_16BITS(&poll_msg->pgmp_round)));
	    bp = (const u_char *) (poll_msg + 1);
	    break;
	}
	case PGM_POLR: {
	    const struct pgm_polr *polr;
	    uint32_t ivl, rnd, mask;

	    polr = (const struct pgm_polr *)(pgm + 1);
	    ND_TCHECK(*polr);
	    bp = (const u_char *) (polr + 1);

	    switch (EXTRACT_16BITS(&polr->pgmp_nla_afi)) {
	    case AFNUM_INET:
		ND_TCHECK2(*bp, sizeof(struct in_addr));
		addrtostr(bp, nla_buf, sizeof(nla_buf));
		bp += sizeof(struct in_addr);
		break;
	    case AFNUM_INET6:
		ND_TCHECK2(*bp, sizeof(struct in6_addr));
		addrtostr6(bp, nla_buf, sizeof(nla_buf));
		bp += sizeof(struct in6_addr);
		break;
	    default:
		goto trunc;
		break;
	    }

	    ND_TCHECK2(*bp, sizeof(uint32_t));
	    ivl = EXTRACT_32BITS(bp);
	    bp += sizeof(uint32_t);

	    ND_TCHECK2(*bp, sizeof(uint32_t));
	    rnd = EXTRACT_32BITS(bp);
	    bp += sizeof(uint32_t);

	    ND_TCHECK2(*bp, sizeof(uint32_t));
	    mask = EXTRACT_32BITS(bp);
	    bp += sizeof(uint32_t);

	    ND_PRINT((ndo, "POLR seq %u round %u nla %s ivl %u rnd 0x%08x "
			 "mask 0x%08x", EXTRACT_32BITS(&polr->pgmp_seq),
			 EXTRACT_16BITS(&polr->pgmp_round), nla_buf, ivl, rnd, mask));
	    break;
	}
	case PGM_ODATA: {
	    const struct pgm_data *odata;

	    odata = (const struct pgm_data *)(pgm + 1);
	    ND_TCHECK(*odata);
	    ND_PRINT((ndo, "ODATA trail %u seq %u",
			 EXTRACT_32BITS(&odata->pgmd_trailseq),
			 EXTRACT_32BITS(&odata->pgmd_seq)));
	    bp = (const u_char *) (odata + 1);
	    break;
	}

	case PGM_RDATA: {
	    const struct pgm_data *rdata;

	    rdata = (const struct pgm_data *)(pgm + 1);
	    ND_TCHECK(*rdata);
	    ND_PRINT((ndo, "RDATA trail %u seq %u",
			 EXTRACT_32BITS(&rdata->pgmd_trailseq),
			 EXTRACT_32BITS(&rdata->pgmd_seq)));
	    bp = (const u_char *) (rdata + 1);
	    break;
	}

	case PGM_NAK:
	case PGM_NULLNAK:
	case PGM_NCF: {
	    const struct pgm_nak *nak;
	    char source_buf[INET6_ADDRSTRLEN], group_buf[INET6_ADDRSTRLEN];

	    nak = (const struct pgm_nak *)(pgm + 1);
	    ND_TCHECK(*nak);
	    bp = (const u_char *) (nak + 1);

	    /*
	     * Skip past the source, saving info along the way
	     * and stopping if we don't have enough.
	     */
	    switch (EXTRACT_16BITS(&nak->pgmn_source_afi)) {
	    case AFNUM_INET:
		ND_TCHECK2(*bp, sizeof(struct in_addr));
		addrtostr(bp, source_buf, sizeof(source_buf));
		bp += sizeof(struct in_addr);
		break;
	    case AFNUM_INET6:
		ND_TCHECK2(*bp, sizeof(struct in6_addr));
		addrtostr6(bp, source_buf, sizeof(source_buf));
		bp += sizeof(struct in6_addr);
		break;
	    default:
		goto trunc;
		break;
	    }

	    /*
	     * Skip past the group, saving info along the way
 	     * and stopping if we don't have enough.
 	     */
 	    bp += (2 * sizeof(uint16_t));
 	    switch (EXTRACT_16BITS(bp)) {
 	    case AFNUM_INET:
 		ND_TCHECK2(*bp, sizeof(struct in_addr));
		addrtostr(bp, group_buf, sizeof(group_buf));
		bp += sizeof(struct in_addr);
		break;
	    case AFNUM_INET6:
		ND_TCHECK2(*bp, sizeof(struct in6_addr));
		addrtostr6(bp, group_buf, sizeof(group_buf));
		bp += sizeof(struct in6_addr);
		break;
	    default:
		goto trunc;
		break;
	    }

	    /*
	     * Options decoding can go here.
	     */
	    switch (pgm->pgm_type) {
		case PGM_NAK:
		    ND_PRINT((ndo, "NAK "));
		    break;
		case PGM_NULLNAK:
		    ND_PRINT((ndo, "NNAK "));
		    break;
		case PGM_NCF:
		    ND_PRINT((ndo, "NCF "));
		    break;
		default:
                    break;
	    }
	    ND_PRINT((ndo, "(%s -> %s), seq %u",
			 source_buf, group_buf, EXTRACT_32BITS(&nak->pgmn_seq)));
	    break;
	}

	case PGM_ACK: {
	    const struct pgm_ack *ack;

	    ack = (const struct pgm_ack *)(pgm + 1);
	    ND_TCHECK(*ack);
	    ND_PRINT((ndo, "ACK seq %u",
			 EXTRACT_32BITS(&ack->pgma_rx_max_seq)));
	    bp = (const u_char *) (ack + 1);
	    break;
	}

	case PGM_SPMR:
	    ND_PRINT((ndo, "SPMR"));
	    break;

	default:
	    ND_PRINT((ndo, "UNKNOWN type 0x%02x", pgm->pgm_type));
	    break;

	}
	if (pgm->pgm_options & PGM_OPT_BIT_PRESENT) {

	    /*
	     * make sure there's enough for the first option header
	     */
	    if (!ND_TTEST2(*bp, PGM_MIN_OPT_LEN)) {
		ND_PRINT((ndo, "[|OPT]"));
		return;
	    }

	    /*
	     * That option header MUST be an OPT_LENGTH option
	     * (see the first paragraph of section 9.1 in RFC 3208).
	     */
	    opt_type = *bp++;
	    if ((opt_type & PGM_OPT_MASK) != PGM_OPT_LENGTH) {
		ND_PRINT((ndo, "[First option bad, should be PGM_OPT_LENGTH, is %u]", opt_type & PGM_OPT_MASK));
		return;
	    }
	    opt_len = *bp++;
	    if (opt_len != 4) {
		ND_PRINT((ndo, "[Bad OPT_LENGTH option, length %u != 4]", opt_len));
		return;
	    }
	    opts_len = EXTRACT_16BITS(bp);
	    if (opts_len < 4) {
		ND_PRINT((ndo, "[Bad total option length %u < 4]", opts_len));
		return;
	    }
	    bp += sizeof(uint16_t);
	    ND_PRINT((ndo, " OPTS LEN %d", opts_len));
	    opts_len -= 4;

	    while (opts_len) {
		if (opts_len < PGM_MIN_OPT_LEN) {
		    ND_PRINT((ndo, "[Total option length leaves no room for final option]"));
		    return;
		}
		if (!ND_TTEST2(*bp, 2)) {
		    ND_PRINT((ndo, " [|OPT]"));
		    return;
		}
		opt_type = *bp++;
		opt_len = *bp++;
		if (opt_len < PGM_MIN_OPT_LEN) {
		    ND_PRINT((ndo, "[Bad option, length %u < %u]", opt_len,
		        PGM_MIN_OPT_LEN));
		    break;
		}
		if (opts_len < opt_len) {
		    ND_PRINT((ndo, "[Total option length leaves no room for final option]"));
		    return;
		}
		if (!ND_TTEST2(*bp, opt_len - 2)) {
		    ND_PRINT((ndo, " [|OPT]"));
		    return;
		}

		switch (opt_type & PGM_OPT_MASK) {
		case PGM_OPT_LENGTH:
#define PGM_OPT_LENGTH_LEN	(2+2)
		    if (opt_len != PGM_OPT_LENGTH_LEN) {
			ND_PRINT((ndo, "[Bad OPT_LENGTH option, length %u != %u]",
			    opt_len, PGM_OPT_LENGTH_LEN));
			return;
		    }
		    ND_PRINT((ndo, " OPTS LEN (extra?) %d", EXTRACT_16BITS(bp)));
		    bp += 2;
		    opts_len -= PGM_OPT_LENGTH_LEN;
		    break;

		case PGM_OPT_FRAGMENT:
#define PGM_OPT_FRAGMENT_LEN	(2+2+4+4+4)
		    if (opt_len != PGM_OPT_FRAGMENT_LEN) {
			ND_PRINT((ndo, "[Bad OPT_FRAGMENT option, length %u != %u]",
			    opt_len, PGM_OPT_FRAGMENT_LEN));
			return;
		    }
		    bp += 2;
		    seq = EXTRACT_32BITS(bp);
		    bp += 4;
		    offset = EXTRACT_32BITS(bp);
		    bp += 4;
		    len = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " FRAG seq %u off %u len %u", seq, offset, len));
		    opts_len -= PGM_OPT_FRAGMENT_LEN;
		    break;

		case PGM_OPT_NAK_LIST:
		    bp += 2;
		    opt_len -= 4;	/* option header */
		    ND_PRINT((ndo, " NAK LIST"));
		    while (opt_len) {
			if (opt_len < 4) {
			    ND_PRINT((ndo, "[Option length not a multiple of 4]"));
			    return;
			}
			ND_TCHECK2(*bp, 4);
			ND_PRINT((ndo, " %u", EXTRACT_32BITS(bp)));
			bp += 4;
			opt_len -= 4;
			opts_len -= 4;
		    }
		    break;

		case PGM_OPT_JOIN:
#define PGM_OPT_JOIN_LEN	(2+2+4)
		    if (opt_len != PGM_OPT_JOIN_LEN) {
			ND_PRINT((ndo, "[Bad OPT_JOIN option, length %u != %u]",
			    opt_len, PGM_OPT_JOIN_LEN));
			return;
		    }
		    bp += 2;
		    seq = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " JOIN %u", seq));
		    opts_len -= PGM_OPT_JOIN_LEN;
		    break;

		case PGM_OPT_NAK_BO_IVL:
#define PGM_OPT_NAK_BO_IVL_LEN	(2+2+4+4)
		    if (opt_len != PGM_OPT_NAK_BO_IVL_LEN) {
			ND_PRINT((ndo, "[Bad OPT_NAK_BO_IVL option, length %u != %u]",
			    opt_len, PGM_OPT_NAK_BO_IVL_LEN));
			return;
		    }
		    bp += 2;
		    offset = EXTRACT_32BITS(bp);
		    bp += 4;
		    seq = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " BACKOFF ivl %u ivlseq %u", offset, seq));
		    opts_len -= PGM_OPT_NAK_BO_IVL_LEN;
		    break;

		case PGM_OPT_NAK_BO_RNG:
#define PGM_OPT_NAK_BO_RNG_LEN	(2+2+4+4)
		    if (opt_len != PGM_OPT_NAK_BO_RNG_LEN) {
			ND_PRINT((ndo, "[Bad OPT_NAK_BO_RNG option, length %u != %u]",
			    opt_len, PGM_OPT_NAK_BO_RNG_LEN));
			return;
		    }
		    bp += 2;
		    offset = EXTRACT_32BITS(bp);
		    bp += 4;
		    seq = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " BACKOFF max %u min %u", offset, seq));
		    opts_len -= PGM_OPT_NAK_BO_RNG_LEN;
		    break;

		case PGM_OPT_REDIRECT:
#define PGM_OPT_REDIRECT_FIXED_LEN	(2+2+2+2)
		    if (opt_len < PGM_OPT_REDIRECT_FIXED_LEN) {
			ND_PRINT((ndo, "[Bad OPT_REDIRECT option, length %u < %u]",
			    opt_len, PGM_OPT_REDIRECT_FIXED_LEN));
			return;
		    }
		    bp += 2;
		    nla_afnum = EXTRACT_16BITS(bp);
		    bp += 2+2;
		    switch (nla_afnum) {
		    case AFNUM_INET:
			if (opt_len != PGM_OPT_REDIRECT_FIXED_LEN + sizeof(struct in_addr)) {
			    ND_PRINT((ndo, "[Bad OPT_REDIRECT option, length %u != %u + address size]",
			        opt_len, PGM_OPT_REDIRECT_FIXED_LEN));
			    return;
			}
			ND_TCHECK2(*bp, sizeof(struct in_addr));
			addrtostr(bp, nla_buf, sizeof(nla_buf));
			bp += sizeof(struct in_addr);
			opts_len -= PGM_OPT_REDIRECT_FIXED_LEN + sizeof(struct in_addr);
			break;
		    case AFNUM_INET6:
			if (opt_len != PGM_OPT_REDIRECT_FIXED_LEN + sizeof(struct in6_addr)) {
			    ND_PRINT((ndo, "[Bad OPT_REDIRECT option, length %u != %u + address size]",
			        PGM_OPT_REDIRECT_FIXED_LEN, opt_len));
			    return;
			}
			ND_TCHECK2(*bp, sizeof(struct in6_addr));
			addrtostr6(bp, nla_buf, sizeof(nla_buf));
			bp += sizeof(struct in6_addr);
			opts_len -= PGM_OPT_REDIRECT_FIXED_LEN + sizeof(struct in6_addr);
			break;
		    default:
			goto trunc;
			break;
		    }

		    ND_PRINT((ndo, " REDIRECT %s",  nla_buf));
		    break;

		case PGM_OPT_PARITY_PRM:
#define PGM_OPT_PARITY_PRM_LEN	(2+2+4)
		    if (opt_len != PGM_OPT_PARITY_PRM_LEN) {
			ND_PRINT((ndo, "[Bad OPT_PARITY_PRM option, length %u != %u]",
			    opt_len, PGM_OPT_PARITY_PRM_LEN));
			return;
		    }
		    bp += 2;
		    len = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " PARITY MAXTGS %u", len));
		    opts_len -= PGM_OPT_PARITY_PRM_LEN;
		    break;

		case PGM_OPT_PARITY_GRP:
#define PGM_OPT_PARITY_GRP_LEN	(2+2+4)
		    if (opt_len != PGM_OPT_PARITY_GRP_LEN) {
			ND_PRINT((ndo, "[Bad OPT_PARITY_GRP option, length %u != %u]",
			    opt_len, PGM_OPT_PARITY_GRP_LEN));
			return;
		    }
		    bp += 2;
		    seq = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " PARITY GROUP %u", seq));
		    opts_len -= PGM_OPT_PARITY_GRP_LEN;
		    break;

		case PGM_OPT_CURR_TGSIZE:
#define PGM_OPT_CURR_TGSIZE_LEN	(2+2+4)
		    if (opt_len != PGM_OPT_CURR_TGSIZE_LEN) {
			ND_PRINT((ndo, "[Bad OPT_CURR_TGSIZE option, length %u != %u]",
			    opt_len, PGM_OPT_CURR_TGSIZE_LEN));
			return;
		    }
		    bp += 2;
		    len = EXTRACT_32BITS(bp);
		    bp += 4;
		    ND_PRINT((ndo, " PARITY ATGS %u", len));
		    opts_len -= PGM_OPT_CURR_TGSIZE_LEN;
		    break;

		case PGM_OPT_NBR_UNREACH:
#define PGM_OPT_NBR_UNREACH_LEN	(2+2)
		    if (opt_len != PGM_OPT_NBR_UNREACH_LEN) {
			ND_PRINT((ndo, "[Bad OPT_NBR_UNREACH option, length %u != %u]",
			    opt_len, PGM_OPT_NBR_UNREACH_LEN));
			return;
		    }
		    bp += 2;
		    ND_PRINT((ndo, " NBR_UNREACH"));
		    opts_len -= PGM_OPT_NBR_UNREACH_LEN;
		    break;

		case PGM_OPT_PATH_NLA:
		    ND_PRINT((ndo, " PATH_NLA [%d]", opt_len));
		    bp += opt_len;
		    opts_len -= opt_len;
		    break;

		case PGM_OPT_SYN:
#define PGM_OPT_SYN_LEN	(2+2)
		    if (opt_len != PGM_OPT_SYN_LEN) {
			ND_PRINT((ndo, "[Bad OPT_SYN option, length %u != %u]",
			    opt_len, PGM_OPT_SYN_LEN));
			return;
		    }
		    bp += 2;
		    ND_PRINT((ndo, " SYN"));
		    opts_len -= PGM_OPT_SYN_LEN;
		    break;

		case PGM_OPT_FIN:
#define PGM_OPT_FIN_LEN	(2+2)
		    if (opt_len != PGM_OPT_FIN_LEN) {
			ND_PRINT((ndo, "[Bad OPT_FIN option, length %u != %u]",
			    opt_len, PGM_OPT_FIN_LEN));
			return;
		    }
		    bp += 2;
		    ND_PRINT((ndo, " FIN"));
		    opts_len -= PGM_OPT_FIN_LEN;
		    break;

		case PGM_OPT_RST:
#define PGM_OPT_RST_LEN	(2+2)
		    if (opt_len != PGM_OPT_RST_LEN) {
			ND_PRINT((ndo, "[Bad OPT_RST option, length %u != %u]",
			    opt_len, PGM_OPT_RST_LEN));
			return;
		    }
		    bp += 2;
		    ND_PRINT((ndo, " RST"));
		    opts_len -= PGM_OPT_RST_LEN;
		    break;

		case PGM_OPT_CR:
		    ND_PRINT((ndo, " CR"));
		    bp += opt_len;
		    opts_len -= opt_len;
		    break;

		case PGM_OPT_CRQST:
#define PGM_OPT_CRQST_LEN	(2+2)
		    if (opt_len != PGM_OPT_CRQST_LEN) {
			ND_PRINT((ndo, "[Bad OPT_CRQST option, length %u != %u]",
			    opt_len, PGM_OPT_CRQST_LEN));
			return;
		    }
		    bp += 2;
		    ND_PRINT((ndo, " CRQST"));
		    opts_len -= PGM_OPT_CRQST_LEN;
		    break;

		case PGM_OPT_PGMCC_DATA:
#define PGM_OPT_PGMCC_DATA_FIXED_LEN	(2+2+4+2+2)
		    if (opt_len < PGM_OPT_PGMCC_DATA_FIXED_LEN) {
			ND_PRINT((ndo, "[Bad OPT_PGMCC_DATA option, length %u < %u]",
			    opt_len, PGM_OPT_PGMCC_DATA_FIXED_LEN));
			return;
		    }
		    bp += 2;
		    offset = EXTRACT_32BITS(bp);
		    bp += 4;
		    nla_afnum = EXTRACT_16BITS(bp);
		    bp += 2+2;
		    switch (nla_afnum) {
		    case AFNUM_INET:
			if (opt_len != PGM_OPT_PGMCC_DATA_FIXED_LEN + sizeof(struct in_addr)) {
			    ND_PRINT((ndo, "[Bad OPT_PGMCC_DATA option, length %u != %u + address size]",
			        opt_len, PGM_OPT_PGMCC_DATA_FIXED_LEN));
			    return;
			}
			ND_TCHECK2(*bp, sizeof(struct in_addr));
			addrtostr(bp, nla_buf, sizeof(nla_buf));
			bp += sizeof(struct in_addr);
			opts_len -= PGM_OPT_PGMCC_DATA_FIXED_LEN + sizeof(struct in_addr);
			break;
		    case AFNUM_INET6:
			if (opt_len != PGM_OPT_PGMCC_DATA_FIXED_LEN + sizeof(struct in6_addr)) {
			    ND_PRINT((ndo, "[Bad OPT_PGMCC_DATA option, length %u != %u + address size]",
			        opt_len, PGM_OPT_PGMCC_DATA_FIXED_LEN));
			    return;
			}
			ND_TCHECK2(*bp, sizeof(struct in6_addr));
			addrtostr6(bp, nla_buf, sizeof(nla_buf));
			bp += sizeof(struct in6_addr);
			opts_len -= PGM_OPT_PGMCC_DATA_FIXED_LEN + sizeof(struct in6_addr);
			break;
		    default:
			goto trunc;
			break;
		    }

		    ND_PRINT((ndo, " PGMCC DATA %u %s", offset, nla_buf));
		    break;

		case PGM_OPT_PGMCC_FEEDBACK:
#define PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN	(2+2+4+2+2)
		    if (opt_len < PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN) {
			ND_PRINT((ndo, "[Bad PGM_OPT_PGMCC_FEEDBACK option, length %u < %u]",
			    opt_len, PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN));
			return;
		    }
		    bp += 2;
		    offset = EXTRACT_32BITS(bp);
		    bp += 4;
		    nla_afnum = EXTRACT_16BITS(bp);
		    bp += 2+2;
		    switch (nla_afnum) {
		    case AFNUM_INET:
			if (opt_len != PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN + sizeof(struct in_addr)) {
			    ND_PRINT((ndo, "[Bad OPT_PGMCC_FEEDBACK option, length %u != %u + address size]",
			        opt_len, PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN));
			    return;
			}
			ND_TCHECK2(*bp, sizeof(struct in_addr));
			addrtostr(bp, nla_buf, sizeof(nla_buf));
			bp += sizeof(struct in_addr);
			opts_len -= PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN + sizeof(struct in_addr);
			break;
		    case AFNUM_INET6:
			if (opt_len != PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN + sizeof(struct in6_addr)) {
			    ND_PRINT((ndo, "[Bad OPT_PGMCC_FEEDBACK option, length %u != %u + address size]",
			        opt_len, PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN));
			    return;
			}
			ND_TCHECK2(*bp, sizeof(struct in6_addr));
			addrtostr6(bp, nla_buf, sizeof(nla_buf));
			bp += sizeof(struct in6_addr);
			opts_len -= PGM_OPT_PGMCC_FEEDBACK_FIXED_LEN + sizeof(struct in6_addr);
			break;
		    default:
			goto trunc;
			break;
		    }

		    ND_PRINT((ndo, " PGMCC FEEDBACK %u %s", offset, nla_buf));
		    break;

		default:
		    ND_PRINT((ndo, " OPT_%02X [%d] ", opt_type, opt_len));
		    bp += opt_len;
		    opts_len -= opt_len;
		    break;
		}

		if (opt_type & PGM_OPT_END)
		    break;
	     }
	}

	ND_PRINT((ndo, " [%u]", length));
	if (ndo->ndo_packettype == PT_PGM_ZMTP1 &&
	    (pgm->pgm_type == PGM_ODATA || pgm->pgm_type == PGM_RDATA))
		zmtp1_print_datagram(ndo, bp, EXTRACT_16BITS(&pgm->pgm_length));

	return;

trunc:
	ND_PRINT((ndo, "[|pgm]"));
	if (ch != '\0')
		ND_PRINT((ndo, ">"));
}

Vulnerability Type: 
CWE ID: CWE-125
Summary: The PGM parser in tcpdump before 4.9.2 has a buffer over-read in print-pgm.c:pgm_print().
Commit Message: CVE-2017-13034/PGM: Add a bounds check.

This fixes a buffer over-read discovered by Bhargava Shastry,
SecT/TU Berlin.

Add a test using the capture file supplied by the reporter(s), modified
so the capture file won't be rejected as an invalid capture.

Move a return to make the code a bit cleaner (i.e., make it more obvious
that if we don't have enough of the PGM header, we just print the source
and destination IP addresses, mark it as incomplete PGM, and don't try
to look at the PGM header).