print-ip.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 741 行 · 第 1/2 页

};

static void
ip_print_demux(netdissect_options *ndo,
	       struct ip_print_demux_state *ipds)
{
	struct protoent *proto;

again:
	switch (ipds->nh) {

	case IPPROTO_AH:
		ipds->nh = *ipds->cp;
		ipds->advance = ah_print(ipds->cp);
		if (ipds->advance <= 0)
			break;
		ipds->cp += ipds->advance;
		ipds->len -= ipds->advance;
		goto again;

	case IPPROTO_ESP:
	{
		int enh, padlen;
		ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
				    (const u_char *)ipds->ip,
				    &enh, &padlen);
		if (ipds->advance <= 0)
			break;
		ipds->cp += ipds->advance;
		ipds->len -= ipds->advance + padlen;
		ipds->nh = enh & 0xff;
		goto again;
	}
	
	case IPPROTO_IPCOMP:
	{
		int enh;
		ipds->advance = ipcomp_print(ipds->cp, &enh);
		if (ipds->advance <= 0)
			break;
		ipds->cp += ipds->advance;
		ipds->len -= ipds->advance;
		ipds->nh = enh & 0xff;
		goto again;
	}

	case IPPROTO_SCTP:
		sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
		break;

	case IPPROTO_DCCP:
		dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
		break;
		
	case IPPROTO_TCP:
		/* pass on the MF bit plus the offset to detect fragments */
		tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
			  ipds->off & (IP_MF|IP_OFFMASK));
		break;
		
	case IPPROTO_UDP:
		/* pass on the MF bit plus the offset to detect fragments */
		udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
			  ipds->off & (IP_MF|IP_OFFMASK));
		break;
		
	case IPPROTO_ICMP:
		/* pass on the MF bit plus the offset to detect fragments */
		icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
			   ipds->off & (IP_MF|IP_OFFMASK));
		break;
		
	case IPPROTO_PIGP:
		/*
		 * XXX - the current IANA protocol number assignments
		 * page lists 9 as "any private interior gateway
		 * (used by Cisco for their IGRP)" and 88 as
		 * "EIGRP" from Cisco.
		 *
		 * Recent BSD <netinet/in.h> headers define
		 * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
		 * We define IP_PROTO_PIGP as 9 and
		 * IP_PROTO_EIGRP as 88; those names better
		 * match was the current protocol number
		 * assignments say.
		 */
		igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
		break;
		
	case IPPROTO_EIGRP:
		eigrp_print(ipds->cp, ipds->len);
		break;
		
	case IPPROTO_ND:
		ND_PRINT((ndo, " nd %d", ipds->len));
		break;

	case IPPROTO_EGP:
		egp_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_OSPF:
		ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
		break;

	case IPPROTO_IGMP:
		igmp_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_IPV4:
		/* DVMRP multicast tunnel (ip-in-ip encapsulation) */
		ip_print(gndo, ipds->cp, ipds->len);
		if (! vflag) {
			ND_PRINT((ndo, " (ipip-proto-4)"));
			return;
		}
		break;
		
#ifdef INET6
	case IPPROTO_IPV6:
		/* ip6-in-ip encapsulation */
		ip6_print(ipds->cp, ipds->len);
		break;
#endif /*INET6*/

	case IPPROTO_RSVP:
		rsvp_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_GRE:
		/* do it */
		gre_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_MOBILE:
		mobile_print(ipds->cp, ipds->len);
		break;

	case IPPROTO_PIM:
		pim_print(ipds->cp,  ipds->len);
		break;

	case IPPROTO_VRRP:
		vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
		break;

	case IPPROTO_PGM:
		pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
		break;

	default:
		if ((proto = getprotobynumber(ipds->nh)) != NULL)
			ND_PRINT((ndo, " %s", proto->p_name));
		else
			ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
		ND_PRINT((ndo, " %d", ipds->len));
		break;
	}
}
	       
void
ip_print_inner(netdissect_options *ndo,
	       const u_char *bp,
	       u_int length, u_int nh,
	       const u_char *bp2)
{
	struct ip_print_demux_state  ipd;

	ipd.ip = (const struct ip *)bp2;
	ipd.cp = bp;
	ipd.len  = length;
	ipd.off  = 0;
	ipd.nh   = nh;
	ipd.advance = 0;

	ip_print_demux(ndo, &ipd);
}


/*
 * print an IP datagram.
 */
void
ip_print(netdissect_options *ndo,
	 const u_char *bp,
	 u_int length)
{
	struct ip_print_demux_state  ipd;
	struct ip_print_demux_state *ipds=&ipd;
	const u_char *ipend;
	u_int hlen;
	u_int16_t sum, ip_sum;
	struct protoent *proto;

	ipds->ip = (const struct ip *)bp;
	if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
	    printf("IP%u ", IP_V(ipds->ip));
	    if (IP_V(ipds->ip) == 6)
		printf(", wrong link-layer encapsulation");
	}
        else if (!eflag)
	    printf("IP ");

	if ((u_char *)(ipds->ip + 1) > snapend) {
		printf("[|ip]");
		return;
	}
	if (length < sizeof (struct ip)) {
		(void)printf("truncated-ip %u", length);
		return;
	}
	hlen = IP_HL(ipds->ip) * 4;
	if (hlen < sizeof (struct ip)) {
		(void)printf("bad-hlen %u", hlen);
		return;
	}

	ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
	if (length < ipds->len)
		(void)printf("truncated-ip - %u bytes missing! ",
			ipds->len - length);
	if (ipds->len < hlen) {
#ifdef GUESS_TSO
            if (ipds->len) {
                (void)printf("bad-len %u", ipds->len);
                return;
            }
            else {
                /* we guess that it is a TSO send */
                ipds->len = length;
            }
#else
            (void)printf("bad-len %u", ipds->len);
            return;
#endif /* GUESS_TSO */
	}

	/*
	 * Cut off the snapshot length to the end of the IP payload.
	 */
	ipend = bp + ipds->len;
	if (ipend < snapend)
		snapend = ipend;

	ipds->len -= hlen;

	ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);

        if (vflag) {
            (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
            /* ECN bits */
            if (ipds->ip->ip_tos & 0x03) {
                switch (ipds->ip->ip_tos & 0x03) {
                case 1:
                    (void)printf(",ECT(1)");
                    break;
                case 2:
                    (void)printf(",ECT(0)");
                    break;
                case 3:
                    (void)printf(",CE");
                }
            }

            if (ipds->ip->ip_ttl >= 1)
                (void)printf(", ttl %u", ipds->ip->ip_ttl);    

	    /*
	     * for the firewall guys, print id, offset.
             * On all but the last stick a "+" in the flags portion.
	     * For unfragmented datagrams, note the don't fragment flag.
	     */

	    (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
                         EXTRACT_16BITS(&ipds->ip->ip_id),
                         (ipds->off & 0x1fff) * 8,
                         bittok2str(ip_frag_values, "none", ipds->off&0xe000),
                         tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
                         ipds->ip->ip_p);

            (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));

            if ((hlen - sizeof(struct ip)) > 0) {
                printf(", options (");
                ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
                printf(")");
            }

	    if ((u_char *)ipds->ip + hlen <= snapend) {
	        sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
		if (sum != 0) {
		    ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
		    (void)printf(", bad cksum %x (->%x)!", ip_sum,
			     in_cksum_shouldbe(ip_sum, sum));
		}
	    }

            printf(")\n    ");
	}

	/*
	 * If this is fragment zero, hand it to the next higher
	 * level protocol.
	 */
	if ((ipds->off & 0x1fff) == 0) {
		ipds->cp = (const u_char *)ipds->ip + hlen;
		ipds->nh = ipds->ip->ip_p;

		if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
		    ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
			(void)printf("%s > %s: ",
				     ipaddr_string(&ipds->ip->ip_src),
				     ipaddr_string(&ipds->ip->ip_dst));
		}
		ip_print_demux(ndo, ipds);
	} else {
	    /* Ultra quiet now means that all this stuff should be suppressed */
	    if (qflag > 1) return;

	    /*
	     * if this isn't the first frag, we're missing the
	     * next level protocol header.  print the ip addr
	     * and the protocol.
	     */
	    if (ipds->off & 0x1fff) {
	        (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
			     ipaddr_string(&ipds->ip->ip_dst));
		if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
		    (void)printf(" %s", proto->p_name);
		else
		    (void)printf(" ip-proto-%d", ipds->ip->ip_p);
	    } 
	}
}

void
ipN_print(register const u_char *bp, register u_int length)
{
	struct ip *ip, hdr;

	ip = (struct ip *)bp;
	if (length < 4) {
		(void)printf("truncated-ip %d", length);
		return;
	}
	memcpy (&hdr, (char *)ip, 4);
	switch (IP_V(&hdr)) {
	case 4:
		ip_print (gndo, bp, length);
		return;
#ifdef INET6
	case 6:
		ip6_print (bp, length);
		return;
#endif
	default:
		(void)printf("unknown ip %d", IP_V(&hdr));
		return;
	}
}

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