print-l2tp.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 715 行 · 第 1/2 页

		printf("S");
	}
}

static void
l2tp_packet_proc_delay_print(void)
{
	printf("obsolete");
}

static void
l2tp_proxy_auth_type_print(const u_char *dat)
{
	u_int16_t *ptr = (u_int16_t *)dat;

	printf("%s", tok2str(l2tp_authentype2str,
			     "AuthType-#%u", EXTRACT_16BITS(ptr)));
}

static void
l2tp_proxy_auth_id_print(const u_char *dat)
{
	u_int16_t *ptr = (u_int16_t *)dat;

	printf("%u", EXTRACT_16BITS(ptr) & L2TP_PROXY_AUTH_ID_MASK);
}

static void
l2tp_call_errors_print(const u_char *dat)
{
	u_int16_t *ptr = (u_int16_t *)dat;
	u_int16_t val_h, val_l;

	ptr++;		/* skip "Reserved" */

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("CRCErr=%u ", (val_h<<16) + val_l);

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("FrameErr=%u ", (val_h<<16) + val_l);

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("HardOver=%u ", (val_h<<16) + val_l);

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("BufOver=%u ", (val_h<<16) + val_l);

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("Timeout=%u ", (val_h<<16) + val_l);

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("AlignErr=%u ", (val_h<<16) + val_l);
}

static void
l2tp_accm_print(const u_char *dat)
{
	u_int16_t *ptr = (u_int16_t *)dat;
	u_int16_t val_h, val_l;

	ptr++;		/* skip "Reserved" */

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("send=%08x ", (val_h<<16) + val_l);

	val_h = EXTRACT_16BITS(ptr); ptr++;
	val_l = EXTRACT_16BITS(ptr); ptr++;
	printf("recv=%08x ", (val_h<<16) + val_l);
}

static void
l2tp_ppp_discon_cc_print(const u_char *dat, u_int length)
{
	u_int16_t *ptr = (u_int16_t *)dat;

	printf("%04x, ", EXTRACT_16BITS(ptr)); ptr++;	/* Disconnect Code */
	printf("%04x ",  EXTRACT_16BITS(ptr)); ptr++;	/* Control Protocol Number */
	printf("%s", tok2str(l2tp_cc_direction2str,
			     "Direction-#%u", *((u_char *)ptr++)));

	if (length > 5) {
		printf(" ");
		print_string((const u_char *)ptr, length-5);
	}
}

static void
l2tp_avp_print(const u_char *dat, int length)
{
	u_int len;
	const u_int16_t *ptr = (u_int16_t *)dat;
	u_int16_t attr_type;
	int hidden = FALSE;

	if (length <= 0) {
		return;
	}

	printf(" ");

	TCHECK(*ptr);	/* Flags & Length */
	len = EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_LEN_MASK;

	/* If it is not long enough to contain the header, we'll give up. */
	if (len < 6)
		goto trunc;

	/* If it goes past the end of the remaining length of the packet,
	   we'll give up. */
	if (len > (u_int)length)
		goto trunc;

	/* If it goes past the end of the remaining length of the captured
	   data, we'll give up. */
	TCHECK2(*ptr, len);
	/* After this point, no need to worry about truncation */

	if (EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_FLAG_MANDATORY) {
		printf("*");
	}
	if (EXTRACT_16BITS(ptr) & L2TP_AVP_HDR_FLAG_HIDDEN) {
		hidden = TRUE;
		printf("?");
	}
	ptr++;

	if (EXTRACT_16BITS(ptr)) {
		/* Vendor Specific Attribute */
	        printf("VENDOR%04x:", EXTRACT_16BITS(ptr)); ptr++;
		printf("ATTR%04x", EXTRACT_16BITS(ptr)); ptr++;
		printf("(");
		print_octets((u_char *)ptr, len-6);
		printf(")");
	} else {
		/* IETF-defined Attributes */
		ptr++;
		attr_type = EXTRACT_16BITS(ptr); ptr++;
		printf("%s", tok2str(l2tp_avp2str, "AVP-#%u", attr_type));
		printf("(");
		if (hidden) {
			printf("???");
		} else {
			switch (attr_type) {
			case L2TP_AVP_MSGTYPE:
				l2tp_msgtype_print((u_char *)ptr);
				break;
			case L2TP_AVP_RESULT_CODE:
				l2tp_result_code_print((u_char *)ptr, len-6);
				break;
			case L2TP_AVP_PROTO_VER:
				l2tp_proto_ver_print(ptr);
				break;
			case L2TP_AVP_FRAMING_CAP:
				l2tp_framing_cap_print((u_char *)ptr);
				break;
			case L2TP_AVP_BEARER_CAP:
				l2tp_bearer_cap_print((u_char *)ptr);
				break;
			case L2TP_AVP_TIE_BREAKER:
				print_octets((u_char *)ptr, 8);
				break;
			case L2TP_AVP_FIRM_VER:
			case L2TP_AVP_ASSND_TUN_ID:
			case L2TP_AVP_RECV_WIN_SIZE:
			case L2TP_AVP_ASSND_SESS_ID:
				print_16bits_val(ptr);
				break;
			case L2TP_AVP_HOST_NAME:
			case L2TP_AVP_VENDOR_NAME:
			case L2TP_AVP_CALLING_NUMBER:
			case L2TP_AVP_CALLED_NUMBER:
			case L2TP_AVP_SUB_ADDRESS:
			case L2TP_AVP_PROXY_AUTH_NAME:
			case L2TP_AVP_PRIVATE_GRP_ID:
				print_string((u_char *)ptr, len-6);
				break;
			case L2TP_AVP_CHALLENGE:
			case L2TP_AVP_INI_RECV_LCP:
			case L2TP_AVP_LAST_SENT_LCP:
			case L2TP_AVP_LAST_RECV_LCP:
			case L2TP_AVP_PROXY_AUTH_CHAL:
			case L2TP_AVP_PROXY_AUTH_RESP:
			case L2TP_AVP_RANDOM_VECTOR:
				print_octets((u_char *)ptr, len-6);
				break;
			case L2TP_AVP_Q931_CC:
				l2tp_q931_cc_print((u_char *)ptr, len-6);
				break;
			case L2TP_AVP_CHALLENGE_RESP:
				print_octets((u_char *)ptr, 16);
				break;
			case L2TP_AVP_CALL_SER_NUM:
			case L2TP_AVP_MINIMUM_BPS:
			case L2TP_AVP_MAXIMUM_BPS:
			case L2TP_AVP_TX_CONN_SPEED:
			case L2TP_AVP_PHY_CHANNEL_ID:
			case L2TP_AVP_RX_CONN_SPEED:
				print_32bits_val((u_int32_t *)ptr);
				break;
			case L2TP_AVP_BEARER_TYPE:
				l2tp_bearer_type_print((u_char *)ptr);
				break;
			case L2TP_AVP_FRAMING_TYPE:
				l2tp_framing_type_print((u_char *)ptr);
				break;
			case L2TP_AVP_PACKET_PROC_DELAY:
				l2tp_packet_proc_delay_print();
				break;
			case L2TP_AVP_PROXY_AUTH_TYPE:
				l2tp_proxy_auth_type_print((u_char *)ptr);
				break;
			case L2TP_AVP_PROXY_AUTH_ID:
				l2tp_proxy_auth_id_print((u_char *)ptr);
				break;
			case L2TP_AVP_CALL_ERRORS:
				l2tp_call_errors_print((u_char *)ptr);
				break;
			case L2TP_AVP_ACCM:
				l2tp_accm_print((u_char *)ptr);
				break;
			case L2TP_AVP_SEQ_REQUIRED:
				break;	/* No Attribute Value */
			case L2TP_AVP_PPP_DISCON_CC:
				l2tp_ppp_discon_cc_print((u_char *)ptr, len-6);
				break;
			default:
				break;
			}
		}
		printf(")");
	}

	l2tp_avp_print(dat+len, length-len);
	return;

 trunc:
	printf("|...");
}


void
l2tp_print(const u_char *dat, u_int length)
{
	const u_int16_t *ptr = (u_int16_t *)dat;
	u_int cnt = 0;			/* total octets consumed */
	u_int16_t pad;
	int flag_t, flag_l, flag_s, flag_o;
	u_int16_t l2tp_len;

	flag_t = flag_l = flag_s = flag_o = FALSE;

	TCHECK(*ptr);	/* Flags & Version */
	if ((EXTRACT_16BITS(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2TP) {
		printf(" l2tp:");
	} else if ((EXTRACT_16BITS(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2F) {
		printf(" l2f:");
		return;		/* nothing to do */
	} else {
		printf(" Unknown Version, neither L2F(1) nor L2TP(2)");
		return;		/* nothing we can do */
	}

	printf("[");
	if (EXTRACT_16BITS(ptr) & L2TP_FLAG_TYPE) {
		flag_t = TRUE;
		printf("T");
	}
	if (EXTRACT_16BITS(ptr) & L2TP_FLAG_LENGTH) {
		flag_l = TRUE;
		printf("L");
	}
	if (EXTRACT_16BITS(ptr) & L2TP_FLAG_SEQUENCE) {
		flag_s = TRUE;
		printf("S");
	}
	if (EXTRACT_16BITS(ptr) & L2TP_FLAG_OFFSET) {
		flag_o = TRUE;
		printf("O");
	}
	if (EXTRACT_16BITS(ptr) & L2TP_FLAG_PRIORITY)
		printf("P");
	printf("]");

	ptr++;
	cnt += 2;

	if (flag_l) {
		TCHECK(*ptr);	/* Length */
		l2tp_len = EXTRACT_16BITS(ptr); ptr++;
		cnt += 2;
	} else {
		l2tp_len = 0;
	}

	TCHECK(*ptr);		/* Tunnel ID */
	printf("(%u/", EXTRACT_16BITS(ptr)); ptr++;
	cnt += 2;
	TCHECK(*ptr);		/* Session ID */
	printf("%u)",  EXTRACT_16BITS(ptr)); ptr++;
	cnt += 2;

	if (flag_s) {
		TCHECK(*ptr);	/* Ns */
		printf("Ns=%u,", EXTRACT_16BITS(ptr)); ptr++;
		cnt += 2;
		TCHECK(*ptr);	/* Nr */
		printf("Nr=%u",  EXTRACT_16BITS(ptr)); ptr++;
		cnt += 2;
	}

	if (flag_o) {
		TCHECK(*ptr);	/* Offset Size */
		pad =  EXTRACT_16BITS(ptr); ptr++;
		ptr += pad / sizeof(*ptr);
		cnt += (2 + pad);
	}

	if (flag_l) {
		if (length < l2tp_len) {
			printf(" Length %u larger than packet", l2tp_len);
			return;
		}
		length = l2tp_len;
	}
	if (length < cnt) {
		printf(" Length %u smaller than header length", length);
		return;
	}
	if (flag_t) {
		if (!flag_l) {
			printf(" No length");
			return;
		}
		if (length - cnt == 0) {
			printf(" ZLB");
		} else {
			l2tp_avp_print((u_char *)ptr, length - cnt);
		}
	} else {
		printf(" {");
		ppp_print((u_char *)ptr, length - cnt);
		printf("}");
	}

	return;

 trunc:
	printf("%s", tstr);
}