traceroute.c

来自「手机嵌入式Linux下可用的busybox源码」· C语言 代码 · 共 648 行 · 第 1/2 页

	static const char * const ttab[] = {
	"Echo Reply",   "ICMP 1",       "ICMP 2",       "Dest Unreachable",
	"Source Quench", "Redirect",    "ICMP 6",       "ICMP 7",
	"Echo",         "ICMP 9",       "ICMP 10",      "Time Exceeded",
	"Param Problem", "Timestamp",   "Timestamp Reply", "Info Request",
	"Info Reply"
	};

	if(t > 16)
		return("OUT-OF-RANGE");

	return(ttab[t]);
}
#endif

static inline int
packet_ok(u_char *buf, int cc, struct sockaddr_in *from, int seq)
{
	struct icmp *icp;
	u_char type, code;
	int hlen;
	struct ip *ip;

	ip = (struct ip *) buf;
	hlen = ip->ip_hl << 2;
	if (cc < hlen + ICMP_MINLEN) {
#ifdef BB_FEATURE_TRACEROUTE_VERBOSE
		if (verbose)
			printf("packet too short (%d bytes) from %s\n", cc,
				inet_ntoa(from->sin_addr));
#endif
		return (0);
	}
	cc -= hlen;
	icp = (struct icmp *)(buf + hlen);
	type = icp->icmp_type; code = icp->icmp_code;
	if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) ||
	    type == ICMP_UNREACH) {
		struct ip *hip;
		struct udphdr *up;

		hip = &icp->icmp_ip;
		hlen = hip->ip_hl << 2;
		up = (struct udphdr *)((u_char *)hip + hlen);
		if (hlen + 12 <= cc && hip->ip_p == IPPROTO_UDP &&
		    up->source == htons(ident) &&
		    up->dest == htons(port+seq))
			return (type == ICMP_TIMXCEED? -1 : code+1);
	}
#ifdef BB_FEATURE_TRACEROUTE_VERBOSE
	if (verbose) {
		int i;
		u_long *lp = (u_long *)&icp->icmp_ip;

		printf("\n%d bytes from %s to %s: icmp type %d (%s) code %d\n",
			cc, inet_ntoa(from->sin_addr), inet_ntoa(ip->ip_dst),
			type, pr_type(type), icp->icmp_code);
		for (i = 4; i < cc ; i += sizeof(long))
			printf("%2d: x%8.8lx\n", i, *lp++);
	}
#endif
	return(0);
}

static void             /* not inline */
send_probe(int seq, int ttl)
{
	struct opacket *op = outpacket;
	struct ip *ip = &op->ip;
	struct udphdr *up = &op->udp;
	int i;
	struct timezone tz;

	ip->ip_off = 0;
	ip->ip_hl = sizeof(*ip) >> 2;
	ip->ip_p = IPPROTO_UDP;
	ip->ip_len = datalen;
	ip->ip_ttl = ttl;
	ip->ip_v = IPVERSION;
	ip->ip_id = htons(ident+seq);

	up->source = htons(ident);
	up->dest = htons(port+seq);
	up->len = htons((u_short)(datalen - sizeof(struct ip)));
	up->check = 0;

	op->seq = seq;
	op->ttl = ttl;
	(void) gettimeofday(&op->tv, &tz);

	i = sendto(sndsock, (char *)outpacket, datalen, 0, &whereto,
		   sizeof(struct sockaddr));
	if (i < 0 || i != datalen)  {
		if (i<0)
			perror("sendto");
		printf("traceroute: wrote %s %d chars, ret=%d\n", hostname,
			datalen, i);
		(void) fflush(stdout);
	}
}


int
#ifndef BB_TRACEROUTE
main(argc, argv)
#else
traceroute_main(argc, argv)
#endif
	int argc;
	char *argv[];
{
	extern char *optarg;
	extern int optind;
	struct hostent *hp;
	struct sockaddr_in from, *to;
	int ch, i, on, probe, seq, tos, ttl;

	int options = 0;                /* socket options */
	char *source = 0;
	int nprobes = 3;

	on = 1;
	seq = tos = 0;
	to = (struct sockaddr_in *)&whereto;
	while ((ch = getopt(argc, argv, "dm:np:q:rs:t:w:v")) != EOF)
		switch(ch) {
		case 'd':
#ifdef BB_FEATURE_TRACEROUTE_SO_DEBUG
			options |= SO_DEBUG;
#endif
			break;
		case 'm':
			max_ttl = atoi(optarg);
			if (max_ttl <= 1)
				error_msg_and_die("max ttl must be >1.");
			break;
		case 'n':
			nflag++;
			break;
		case 'p':
			port = atoi(optarg);
			if (port < 1)
				error_msg_and_die("port must be >0.");
			break;
		case 'q':
			nprobes = atoi(optarg);
			if (nprobes < 1)
				error_msg_and_die("nprobes must be >0.");
			break;
		case 'r':
			options |= SO_DONTROUTE;
			break;
		case 's':
			/*
			 * set the ip source address of the outbound
			 * probe (e.g., on a multi-homed host).
			 */
			source = optarg;
			break;
		case 't':
			tos = atoi(optarg);
			if (tos < 0 || tos > 255)
				error_msg_and_die("tos must be 0 to 255.");
			break;
		case 'v':
#ifdef BB_FEATURE_TRACEROUTE_VERBOSE
			verbose++;
#endif
			break;
		case 'w':
			waittime = atoi(optarg);
			if (waittime <= 1)
				error_msg_and_die("wait must be >1 sec.");
			break;
		default:
			show_usage();
		}
	argc -= optind;
	argv += optind;

	if (argc < 1)
		show_usage();

	setlinebuf (stdout);

	memset(&whereto, 0, sizeof(struct sockaddr));
	hp = xgethostbyname(*argv);
			to->sin_family = hp->h_addrtype;
	memcpy(&to->sin_addr, hp->h_addr, hp->h_length);
			hostname = (char *)hp->h_name;
	if (*++argv)
		datalen = atoi(*argv);
	if (datalen < 0 || datalen >= MAXPACKET - sizeof(struct opacket))
		error_msg_and_die("packet size must be 0 <= s < %d.",
		    MAXPACKET - sizeof(struct opacket));
	datalen += sizeof(struct opacket);
	outpacket = (struct opacket *)xmalloc((unsigned)datalen);
	memset(outpacket, 0, datalen);
	outpacket->ip.ip_dst = to->sin_addr;
	outpacket->ip.ip_tos = tos;
	outpacket->ip.ip_v = IPVERSION;
	outpacket->ip.ip_id = 0;

	ident = (getpid() & 0xffff) | 0x8000;

	if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
		perror_msg_and_die(can_not_create_raw_socket);

	s = create_icmp_socket();

#ifdef BB_FEATURE_TRACEROUTE_SO_DEBUG
	if (options & SO_DEBUG)
		(void) setsockopt(s, SOL_SOCKET, SO_DEBUG,
				  (char *)&on, sizeof(on));
#endif
	if (options & SO_DONTROUTE)
		(void) setsockopt(s, SOL_SOCKET, SO_DONTROUTE,
				  (char *)&on, sizeof(on));
#ifdef SO_SNDBUF
	if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen,
		       sizeof(datalen)) < 0)
		perror_msg_and_die("SO_SNDBUF");
#endif /* SO_SNDBUF */
#ifdef IP_HDRINCL
	if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
		       sizeof(on)) < 0)
		perror_msg_and_die("IP_HDRINCL");
#endif /* IP_HDRINCL */
#ifdef BB_FEATURE_TRACEROUTE_SO_DEBUG
	if (options & SO_DEBUG)
		(void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
				  (char *)&on, sizeof(on));
#endif
	if (options & SO_DONTROUTE)
		(void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
				  (char *)&on, sizeof(on));

	if (source) {
		memset(&from, 0, sizeof(struct sockaddr));
		from.sin_family = AF_INET;
		from.sin_addr.s_addr = inet_addr(source);
		if (from.sin_addr.s_addr == -1)
			error_msg_and_die("unknown host %s", source);
		outpacket->ip.ip_src = from.sin_addr;
#ifndef IP_HDRINCL
		if (bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0)
			perror_msg_and_die("bind");
#endif /* IP_HDRINCL */
	}

	fprintf(stderr, "traceroute to %s (%s)", hostname,
		inet_ntoa(to->sin_addr));
	if (source)
		fprintf(stderr, " from %s", source);
	fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl, datalen);

	for (ttl = 1; ttl <= max_ttl; ++ttl) {
		u_long lastaddr = 0;
		int got_there = 0;
		int unreachable = 0;

		printf("%2d ", ttl);
		for (probe = 0; probe < nprobes; ++probe) {
			int cc, reset_timer;
			struct timeval t1, t2;
			struct timezone tz;
			struct ip *ip;

			(void) gettimeofday(&t1, &tz);
			send_probe(++seq, ttl);
			reset_timer = 1;
			while ((cc = wait_for_reply(s, &from, reset_timer)) != 0) {
				(void) gettimeofday(&t2, &tz);
				if ((i = packet_ok(packet, cc, &from, seq))) {
					reset_timer = 1;
					if (from.sin_addr.s_addr != lastaddr) {
						print(packet, cc, &from);
						lastaddr = from.sin_addr.s_addr;
					}
					printf("  %g ms", deltaT(&t1, &t2));
					switch(i - 1) {
					case ICMP_UNREACH_PORT:
						ip = (struct ip *)packet;
						if (ip->ip_ttl <= 1)
							printf(" !");
						++got_there;
						break;
					case ICMP_UNREACH_NET:
						++unreachable;
						printf(" !N");
						break;
					case ICMP_UNREACH_HOST:
						++unreachable;
						printf(" !H");
						break;
					case ICMP_UNREACH_PROTOCOL:
						++got_there;
						printf(" !P");
						break;
					case ICMP_UNREACH_NEEDFRAG:
						++unreachable;
						printf(" !F");
						break;
					case ICMP_UNREACH_SRCFAIL:
						++unreachable;
						printf(" !S");
						break;
					}
					break;
				} else
					reset_timer = 0;
			}
			if (cc == 0)
				printf(" *");
			(void) fflush(stdout);
		}
		putchar('\n');
		if (got_there || unreachable >= nprobes-1)
			exit(0);
	}

	return 0;
}