print-ppp.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 1,758 行 · 第 1/3 页

		return 0;
	if (len < 2) {
	        printf("\n\t  %s Option (0x%02x), length %u (bogus, should be >= 2)",
        	       tok2str(ccpconfopts_values, "Unknown", opt),
	               opt,
        	       len);
        	return 0;
        }

        printf("\n\t  %s Option (0x%02x), length %u:",
               tok2str(ccpconfopts_values, "Unknown", opt),
               opt,
               len);

	switch (opt) {
                /* fall through --> default: nothing supported yet */
	case CCPOPT_OUI:
	case CCPOPT_PRED1:
	case CCPOPT_PRED2:
	case CCPOPT_PJUMP:
	case CCPOPT_HPPPC:
	case CCPOPT_STACLZS:
	case CCPOPT_MPPC:
	case CCPOPT_GFZA:
	case CCPOPT_V42BIS:
	case CCPOPT_BSDCOMP:
	case CCPOPT_LZSDCP:
	case CCPOPT_MVRCA:
	case CCPOPT_DEC:
	case CCPOPT_DEFLATE:
	case CCPOPT_RESV:
	default:
                if(vflag<2)
                        print_unknown_data(&p[2],"\n\t    ",len-2);
		break;
	}
        if (vflag>1)
                print_unknown_data(&p[2],"\n\t    ",len-2); /* exclude TLV header */

	return len;

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

/* BACP config options */
static int
print_bacp_config_options(const u_char *p, int length)
{
	int len, opt;

	if (length < 2)
		return 0;
	TCHECK2(*p, 2);
	len = p[1];
	opt = p[0];
	if (length < len)
		return 0;
	if (len < 2) {
	        printf("\n\t  %s Option (0x%02x), length %u (bogus, should be >= 2)",
        	       tok2str(bacconfopts_values, "Unknown", opt),
	               opt,
        	       len);
        	return 0;
        }

        printf("\n\t  %s Option (0x%02x), length %u:",
               tok2str(bacconfopts_values, "Unknown", opt),
               opt,
               len);

	switch (opt) {
	case BACPOPT_FPEER:
		TCHECK2(*(p + 2), 4);
		printf(", Magic-Num 0x%08x", EXTRACT_32BITS(p + 2));
                break;
	default:
                if(vflag<2)
                        print_unknown_data(&p[2],"\n\t    ",len-2);
		break;
	}
        if (vflag>1)
                print_unknown_data(&p[2],"\n\t    ",len-2); /* exclude TLV header */

	return len;

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


static void
ppp_hdlc(const u_char *p, int length)
{
	u_char *b, *s, *t, c;
	int i, proto;
	const void *se;

	b = (u_int8_t *)malloc(length);
	if (b == NULL)
		return;

	/*
	 * Unescape all the data into a temporary, private, buffer.
	 * Do this so that we dont overwrite the original packet
	 * contents.
	 */
	for (s = (u_char *)p, t = b, i = length; i > 0; i--) {
		c = *s++;
		if (c == 0x7d) {
			if (i > 1) {
				i--;
				c = *s++ ^ 0x20;
			} else
				continue;
		}
		*t++ = c;
	}

	se = snapend;
	snapend = t;

        /* now lets guess about the payload codepoint format */
        proto = *b; /* start with a one-octet codepoint guess */
        
        switch (proto) {
        case PPP_IP:
		ip_print(gndo, b+1, t - b - 1);
		goto cleanup;
#ifdef INET6
        case PPP_IPV6:
            ip6_print(b+1, t - b - 1);
            goto cleanup;
#endif
        default: /* no luck - try next guess */
            break;
        }

        proto = EXTRACT_16BITS(b); /* next guess - load two octets */

        switch (proto) {
        case (PPP_ADDRESS << 8 | PPP_CONTROL): /* looks like a PPP frame */
            proto = EXTRACT_16BITS(b+2); /* load the PPP proto-id */
            handle_ppp(proto, b+4, t - b - 4);
            break;
        default: /* last guess - proto must be a PPP proto-id */
            handle_ppp(proto, b+2, t - b - 2);
            break;
        }

cleanup:
        snapend = se;
	free(b);
        return;
}


/* PPP */
static void
handle_ppp(u_int proto, const u_char *p, int length)
{
        if ((proto & 0xff00) == 0x7e00) {/* is this an escape code ? */
            ppp_hdlc(p-1, length);
            return;
        }

	switch (proto) {
	case PPP_LCP: /* fall through */
	case PPP_IPCP:
	case PPP_OSICP:
	case PPP_MPLSCP:
	case PPP_IPV6CP:
	case PPP_CCP:
	case PPP_BACP:
		handle_ctrl_proto(proto, p, length);
		break;
        case PPP_ML:
                handle_mlppp(p, length);
                break;
	case PPP_CHAP:
		handle_chap(p, length);
		break;
	case PPP_PAP:
		handle_pap(p, length);
		break;
	case PPP_BAP:		/* XXX: not yet completed */
		handle_bap(p, length);
		break;
	case ETHERTYPE_IP:	/*XXX*/
        case PPP_VJNC:
	case PPP_IP:
		ip_print(gndo, p, length);
		break;
#ifdef INET6
	case ETHERTYPE_IPV6:	/*XXX*/
	case PPP_IPV6:
		ip6_print(p, length);
		break;
#endif
	case ETHERTYPE_IPX:	/*XXX*/
	case PPP_IPX:
		ipx_print(p, length);
		break;
	case PPP_OSI:
	        isoclns_print(p, length, length);
	        break;
	case PPP_MPLS_UCAST:
	case PPP_MPLS_MCAST:
		mpls_print(p, length);
		break;
	case PPP_COMP:
		printf("compressed PPP data");
		break;
	default:
		printf("%s ", tok2str(ppptype2str, "unknown PPP protocol (0x%04x)", proto));
		print_unknown_data(p,"\n\t",length);
		break;
	}
}

/* Standard PPP printer */
u_int
ppp_print(register const u_char *p, u_int length)
{
	u_int proto,ppp_header;
        u_int olen = length; /* _o_riginal length */
	u_int hdr_len = 0;

	/*
	 * Here, we assume that p points to the Address and Control
	 * field (if they present).
	 */
	if (length < 2)
		goto trunc;
	TCHECK2(*p, 2);
        ppp_header = EXTRACT_16BITS(p);

        switch(ppp_header) {
        case (PPP_WITHDIRECTION_IN  << 8 | PPP_CONTROL):
            if (eflag) printf("In  ");
            p += 2;
            length -= 2;
            hdr_len += 2;
            break;
        case (PPP_WITHDIRECTION_OUT << 8 | PPP_CONTROL):
            if (eflag) printf("Out ");
            p += 2;
            length -= 2;
            hdr_len += 2;
            break;
        case (PPP_ADDRESS << 8 | PPP_CONTROL):
            p += 2;			/* ACFC not used */
            length -= 2;
            hdr_len += 2;
            break;

        default:
            break;
        }

	if (length < 2)
		goto trunc;
	TCHECK(*p);
	if (*p % 2) {
		proto = *p;		/* PFC is used */
		p++;
		length--;
		hdr_len++;
	} else {
		TCHECK2(*p, 2);
		proto = EXTRACT_16BITS(p);
		p += 2;
		length -= 2;
		hdr_len += 2;
	}

        if (eflag)
            printf("%s (0x%04x), length %u: ",
                   tok2str(ppptype2str, "unknown", proto),
                   proto,
                   olen);

	handle_ppp(proto, p, length);
	return (hdr_len);
trunc:
	printf("[|ppp]");
	return (0);
}


/* PPP I/F printer */
u_int
ppp_if_print(const struct pcap_pkthdr *h, register const u_char *p)
{
	register u_int length = h->len;
	register u_int caplen = h->caplen;

	if (caplen < PPP_HDRLEN) {
		printf("[|ppp]");
		return (caplen);
	}

#if 0
	/*
	 * XXX: seems to assume that there are 2 octets prepended to an
	 * actual PPP frame. The 1st octet looks like Input/Output flag
	 * while 2nd octet is unknown, at least to me
	 * ([e-mail]).
	 *
	 * That was what the original tcpdump code did.
	 *
	 * FreeBSD's "if_ppp.c" *does* set the first octet to 1 for outbound
	 * packets and 0 for inbound packets - but only if the
	 * protocol field has the 0x8000 bit set (i.e., it's a network
	 * control protocol); it does so before running the packet through
	 * "bpf_filter" to see if it should be discarded, and to see
	 * if we should update the time we sent the most recent packet...
	 *
	 * ...but it puts the original address field back after doing
	 * so.
	 *
	 * NetBSD's "if_ppp.c" doesn't set the first octet in that fashion.
	 *
	 * I don't know if any PPP implementation handed up to a BPF
	 * device packets with the first octet being 1 for outbound and
	 * 0 for inbound packets, so I ([e-mail]) don't know
	 * whether that ever needs to be checked or not.
	 *
	 * Note that NetBSD has a DLT_PPP_SERIAL, which it uses for PPP,
	 * and its tcpdump appears to assume that the frame always
	 * begins with an address field and a control field, and that
	 * the address field might be 0x0f or 0x8f, for Cisco
	 * point-to-point with HDLC framing as per section 4.3.1 of RFC
	 * 1547, as well as 0xff, for PPP in HDLC-like framing as per
	 * RFC 1662.
	 *
	 * (Is the Cisco framing in question what DLT_C_HDLC, in
	 * BSD/OS, is?)
	 */
	if (eflag)
		printf("%c %4d %02x ", p[0] ? 'O' : 'I', length, p[1]);
#endif

	ppp_print(p, length);

	return (0);
}

/*
 * PPP I/F printer to use if we know that RFC 1662-style PPP in HDLC-like
 * framing, or Cisco PPP with HDLC framing as per section 4.3.1 of RFC 1547,
 * is being used (i.e., we don't check for PPP_ADDRESS and PPP_CONTROL,
 * discard them *if* those are the first two octets, and parse the remaining
 * packet as a PPP packet, as "ppp_print()" does).
 *
 * This handles, for example, DLT_PPP_SERIAL in NetBSD.
 */
u_int
ppp_hdlc_if_print(const struct pcap_pkthdr *h, register const u_char *p)
{
	register u_int length = h->len;
	register u_int caplen = h->caplen;
	u_int proto;
	u_int hdrlen = 0;

	if (caplen < 2) {
		printf("[|ppp]");
		return (caplen);
	}

	switch (p[0]) {

	case PPP_ADDRESS:
		if (caplen < 4) {
			printf("[|ppp]");
			return (caplen);
		}

		if (eflag)
			printf("%02x %02x %d ", p[0], p[1], length);
		p += 2;
		length -= 2;
		hdrlen += 2;

		proto = EXTRACT_16BITS(p);
		p += 2;
		length -= 2;
		hdrlen += 2;
		printf("%s: ", tok2str(ppptype2str, "unknown PPP protocol (0x%04x)", proto));

		handle_ppp(proto, p, length);
		break;

	case CHDLC_UNICAST:
	case CHDLC_BCAST:
		return (chdlc_if_print(h, p));

	default:
		if (eflag)
			printf("%02x %02x %d ", p[0], p[1], length);
		p += 2;
		length -= 2;
		hdrlen += 2;

		/*
		 * XXX - NetBSD's "ppp_netbsd_serial_if_print()" treats
		 * the next two octets as an Ethernet type; does that
		 * ever happen?
		 */
		printf("unknown addr %02x; ctrl %02x", p[0], p[1]);
		break;
	}

	return (hdrlen);
}

#define PPP_BSDI_HDRLEN 24

/* BSD/OS specific PPP printer */
u_int
ppp_bsdos_if_print(const struct pcap_pkthdr *h _U_, register const u_char *p _U_)
{
	register int hdrlength;
#ifdef __bsdi__
	register u_int length = h->len;
	register u_int caplen = h->caplen;
	u_int16_t ptype;
	const u_char *q;
	int i;

	if (caplen < PPP_BSDI_HDRLEN) {
		printf("[|ppp]");
		return (caplen)
	}

	hdrlength = 0;

#if 0
	if (p[0] == PPP_ADDRESS && p[1] == PPP_CONTROL) {
		if (eflag)
			printf("%02x %02x ", p[0], p[1]);
		p += 2;
		hdrlength = 2;
	}

	if (eflag)
		printf("%d ", length);
	/* Retrieve the protocol type */
	if (*p & 01) {
		/* Compressed protocol field */
		ptype = *p;
		if (eflag)
			printf("%02x ", ptype);
		p++;
		hdrlength += 1;
	} else {
		/* Un-compressed protocol field */
		ptype = ntohs(*(u_int16_t *)p);
		if (eflag)
			printf("%04x ", ptype);
		p += 2;
		hdrlength += 2;
	}
#else
	ptype = 0;	/*XXX*/
	if (eflag)
		printf("%c ", p[SLC_DIR] ? 'O' : 'I');
	if (p[SLC_LLHL]) {
		/* link level header */
		struct ppp_header *ph;

		q = p + SLC_BPFHDRLEN;
		ph = (struct ppp_header *)q;
		if (ph->phdr_addr == PPP_ADDRESS
		 && ph->phdr_ctl == PPP_CONTROL) {
			if (eflag)
				printf("%02x %02x ", q[0], q[1]);
			ptype = ntohs(ph->phdr_type);
			if (eflag && (ptype == PPP_VJC || ptype == PPP_VJNC)) {
				printf("%s ", tok2str(ppptype2str,
						"proto-#%d", ptype));
			}
		} else {
			if (eflag) {
				printf("LLH=[");
				for (i = 0; i < p[SLC_LLHL]; i++)
					printf("%02x", q[i]);
				printf("] ");
			}
		}
	}
	if (eflag)
		printf("%d ", length);
	if (p[SLC_CHL]) {
		q = p + SLC_BPFHDRLEN + p[SLC_LLHL];

		switch (ptype) {
		case PPP_VJC:
			ptype = vjc_print(q, ptype);
			hdrlength = PPP_BSDI_HDRLEN;
			p += hdrlength;
			switch (ptype) {
			case PPP_IP:
				ip_print(p, length);
				break;
#ifdef INET6
			case PPP_IPV6:
				ip6_print(p, length);
				break;
#endif
			case PPP_MPLS_UCAST:
			case PPP_MPLS_MCAST:
				mpls_print(p, length);
				break;
			}
			goto printx;
		case PPP_VJNC:
			ptype = vjc_print(q, ptype);
			hdrlength = PPP_BSDI_HDRLEN;
			p += hdrlength;
			switch (ptype) {
			case PPP_IP:
				ip_print(p, length);
				break;
#ifdef INET6
			case PPP_IPV6:
				ip6_print(p, length);
				break;
#endif
			case PPP_MPLS_UCAST:
			case PPP_MPLS_MCAST:
				mpls_print(p, length);
				break;
			}
			goto printx;
		default:
			if (eflag) {
				printf("CH=[");
				for (i = 0; i < p[SLC_LLHL]; i++)
					printf("%02x", q[i]);
				printf("] ");
			}
			break;
		}
	}

	hdrlength = PPP_BSDI_HDRLEN;
#endif

	length -= hdrlength;
	p += hdrlength;

	switch (ptype) {
	case PPP_IP:
		ip_print(p, length);
		break;
#ifdef INET6
	case PPP_IPV6:
		ip6_print(p, length);
		break;
#endif
        case PPP_MPLS_UCAST:
        case PPP_MPLS_MCAST:
                mpls_print(p, length);
                break;
	default:
		printf("%s ", tok2str(ppptype2str, "unknown PPP protocol (0x%04x)", ptype));
	}

printx:
#else /* __bsdi */
	hdrlength = 0;
#endif /* __bsdi__ */
	return (hdrlength);
}


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