724c7df68 — BusyBox

Subject

traceroute: untangle main loop

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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Commit Diff GitHub →

networking/traceroute.c +106 -112

networking/traceroute.c+106 -112

@@ -463,6 +463,8 @@ wait_for_reply(unsigned timestamp_us, int left_ms)
	recv_pkt, sizeof(recv_pkt),
	/flags:/ MSG_DONTWAIT,
	&G.from_lsa->u.sa, G.to, G.from_lsa->len);
+	if (read_len < 0)
+	bb_perror_msg_and_die("recv");
	t = monotonic_us();
	left_ms -= (t - timestamp_us) / 1000;
	*timestamp_us = t;
@@ -1076,147 +1078,139 @@ common_traceroute_main(int op, char **argv)
	for (ttl = G.first_ttl; ttl <= G.max_ttl; ++ttl) {
	int probe;
	int unreachable = 0; /* counter */
-	int gotlastaddr = 0; /* flags */
	int got_there = 0;

	printf("%2d", ttl);
	for (probe = 0; probe < G.nprobes; ++probe) {
-	int read_len;
	unsigned t1;
	unsigned t2;
	int left_ms;
+	int read_len;
+	int icmp_code;

	fflush_all();
	if (probe != 0)
	msleep(G.pausemsecs);

	send_probe(++seq, ttl);
-	t2 = t1 = monotonic_us();

+	t2 = t1 = monotonic_us();
	left_ms = waittime * 1000;
-	/* NB: wait_for_reply() fills "G.from_lsa" and "G.to" with
-	* "where it came from" and "what local address it arrived to"
-	* addresses.
-	*/
-	while ((read_len = wait_for_reply(&t2, &left_ms)) != 0) {
-	int icmp_code;
-
-	/* Recv'ed a packet, or read error */
-	/* t2 = monotonic_us() - set by wait_for_reply */
-
-	if (read_len < 0)
-	continue;
-	icmp_code = packet_ok(read_len, seq);
-	/* Skip short packet */
-	if (icmp_code == 0)
-	continue;
-
-	if (!gotlastaddr
-	\|\| (memcmp(lastaddr, &G.from_lsa->u.sa, G.from_lsa->len) != 0)
-	) {
-	print(read_len);
-	memcpy(lastaddr, &G.from_lsa->u.sa, G.from_lsa->len);
-	gotlastaddr = 1;
+	for (;;) {
+	/* NB: wait_for_reply() fills "G.from_lsa" and "G.to" with
+	* "where it came from" and "what local address it arrived to"
+	* addresses. Sets t2 = monotonic_us(), updates left_ms.
+	*/
+	read_len = wait_for_reply(&t2, &left_ms);
+
+	if (read_len == 0) { /* there was no packet at all? */
+	printf(" *");
+	goto next_probe;
	}
+	icmp_code = packet_ok(read_len, seq);
+	if (icmp_code != 0)
+	break; /* got a good response */
+	/* unrecognized type/code or too short, back to recv */
+	}

-	print_delta_ms(t1, t2);
-
-	if (G.from_lsa->u.sa.sa_family == AF_INET) {
-	if (op & OPT_TTL_FLAG) {
-	struct ip ip = (struct ip )recv_pkt;
-	printf(" (%d)", ip->ip_ttl);
-	}
+	if (probe == 0
+	\|\| (memcmp(lastaddr, &G.from_lsa->u.sa, G.from_lsa->len) != 0)
+	) {
+	print(read_len);
+	memcpy(lastaddr, &G.from_lsa->u.sa, G.from_lsa->len);
+	}
+	print_delta_ms(t1, t2);
+	if (G.from_lsa->u.sa.sa_family == AF_INET) {
+	if (op & OPT_TTL_FLAG) {
+	struct ip ip = (struct ip )recv_pkt;
+	printf(" (%d)", ip->ip_ttl);
	}
+	}

-	/* Got a "time exceeded in transit" icmp message? */
-	if (icmp_code == -1)
-	break;
+	/* Got a "time exceeded in transit" icmp message? */
+	if (icmp_code == -1)
+	continue;

-	icmp_code--;
-	switch (icmp_code) {
+	icmp_code--;
+	switch (icmp_code) {
	#if ENABLE_TRACEROUTE6
-	case ICMP6_DST_UNREACH_NOPORT << 8:
-	got_there = 1;
-	break;
+	case ICMP6_DST_UNREACH_NOPORT << 8:
+	got_there = 1;
+	break;
	#endif
-	case ICMP_UNREACH_PORT: {
-	struct ip ip = (struct ip )recv_pkt;
-	if (ip->ip_ttl <= 1)
-	printf(" !");
-	got_there = 1;
-	break;
-	}
-	case ICMP_UNREACH_NET:
+	case ICMP_UNREACH_PORT: {
+	struct ip ip = (struct ip )recv_pkt;
+	if (ip->ip_ttl <= 1)
+	printf(" !");
+	got_there = 1;
+	break;
+	}
+	case ICMP_UNREACH_NET:
	#if ENABLE_TRACEROUTE6 && (ICMP6_DST_UNREACH_NOROUTE != ICMP_UNREACH_NET)
-	case ICMP6_DST_UNREACH_NOROUTE << 8:
+	case ICMP6_DST_UNREACH_NOROUTE << 8:
	#endif
-	printf(" !N");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_HOST:
+	printf(" !N");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_HOST:
	#if ENABLE_TRACEROUTE6
-	case ICMP6_DST_UNREACH_ADDR << 8:
+	case ICMP6_DST_UNREACH_ADDR << 8:
	#endif
-	printf(" !H");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_PROTOCOL:
-	printf(" !P");
-	got_there = 1;
-	break;
-	case ICMP_UNREACH_NEEDFRAG:
-	printf(" !F-%d", pmtu);
-	++unreachable;
-	break;
-	case ICMP_UNREACH_SRCFAIL:
+	printf(" !H");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_PROTOCOL:
+	printf(" !P");
+	got_there = 1;
+	break;
+	case ICMP_UNREACH_NEEDFRAG:
+	printf(" !F-%d", pmtu);
+	++unreachable;
+	break;
+	case ICMP_UNREACH_SRCFAIL:
	#if ENABLE_TRACEROUTE6
-	case ICMP6_DST_UNREACH_ADMIN << 8:
+	case ICMP6_DST_UNREACH_ADMIN << 8:
	#endif
-	printf(" !S");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_FILTER_PROHIB:
-	case ICMP_UNREACH_NET_PROHIB: /* misuse */
-	printf(" !A");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_HOST_PROHIB:
-	printf(" !C");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_HOST_PRECEDENCE:
-	printf(" !V");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_PRECEDENCE_CUTOFF:
-	printf(" !C");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_NET_UNKNOWN:
-	case ICMP_UNREACH_HOST_UNKNOWN:
-	printf(" !U");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_ISOLATED:
-	printf(" !I");
-	++unreachable;
-	break;
-	case ICMP_UNREACH_TOSNET:
-	case ICMP_UNREACH_TOSHOST:
-	printf(" !T");
-	++unreachable;
-	break;
-	default:
-	printf(" !<%d>", icmp_code);
-	++unreachable;
-	break;
-	}
+	printf(" !S");
+	++unreachable;
	break;
-	} /* while (wait and read a packet) */
-
-	/* there was no packet at all? */
-	if (read_len == 0)
-	printf(" *");
+	case ICMP_UNREACH_FILTER_PROHIB:
+	case ICMP_UNREACH_NET_PROHIB: /* misuse */
+	printf(" !A");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_HOST_PROHIB:
+	printf(" !C");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_HOST_PRECEDENCE:
+	printf(" !V");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_PRECEDENCE_CUTOFF:
+	printf(" !C");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_NET_UNKNOWN:
+	case ICMP_UNREACH_HOST_UNKNOWN:
+	printf(" !U");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_ISOLATED:
+	printf(" !I");
+	++unreachable;
+	break;
+	case ICMP_UNREACH_TOSNET:
+	case ICMP_UNREACH_TOSHOST:
+	printf(" !T");
+	++unreachable;
+	break;
+	default:
+	printf(" !<%d>", icmp_code);
+	++unreachable;
+	break;
+	}
+	next_probe: ;
	} /* for (nprobes) */

	bb_putchar('\n');