a348b4557
Denys Vlasenko
2011-05-05
Subject
traceroute: properly reduce poll timeout
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Commit Diff GitHub →
networking/traceroute.c+37 -24
| @@ -398,18 +398,23 @@ static len_and_sockaddr* dup_sockaddr(const len_and_sockaddr *lsa) | |
| static int | |
| - | wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to) |
| + | wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to, unsigned *timestamp_us, int *left_ms) |
| { | |
| struct pollfd pfd[1]; | |
| int read_len = 0; | |
| pfd[0].fd = rcvsock; | |
| pfd[0].events = POLLIN; | |
| - | if (safe_poll(pfd, 1, waittime * 1000) > 0) { |
| + | if (*left_ms >= 0 && safe_poll(pfd, 1, *left_ms) > 0) { |
| + | unsigned t; |
| + | |
| read_len = recv_from_to(rcvsock, | |
| recv_pkt, sizeof(recv_pkt), | |
| - | /*flags:*/ 0, |
| + | /*flags:*/ MSG_DONTWAIT, |
| &from_lsa->u.sa, to, from_lsa->len); | |
| + | t = monotonic_us(); |
| + | *left_ms -= (t - *timestamp_us) / 1000; |
| + | *timestamp_us = t; |
| } | |
| return read_len; | |
| @@ -730,7 +735,7 @@ packet_ok(int read_len, len_and_sockaddr *from_lsa, | |
| type, pr_type(type), icp->icmp6_code); | |
| read_len -= sizeof(struct icmp6_hdr); | |
| - | for (i = 0; i < read_len ; i++) { |
| + | for (i = 0; i < read_len; i++) { |
| if (i % 16 == 0) | |
| printf("%04x:", i); | |
| if (i % 4 == 0) | |
| @@ -819,7 +824,6 @@ print_delta_ms(unsigned t1p, unsigned t2p) | |
| static int | |
| common_traceroute_main(int op, char **argv) | |
| { | |
| - | int i; |
| int minpacket; | |
| int tos = 0; | |
| int max_ttl = 30; | |
| @@ -973,6 +977,7 @@ common_traceroute_main(int op, char **argv) | |
| #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE && defined IP_OPTIONS | |
| if (lsrr > 0) { | |
| unsigned char optlist[MAX_IPOPTLEN]; | |
| + | unsigned size; |
| /* final hop */ | |
| gwlist[lsrr] = dest_lsa->u.sin.sin_addr.s_addr; | |
| @@ -982,14 +987,14 @@ common_traceroute_main(int op, char **argv) | |
| optlist[0] = IPOPT_NOP; | |
| /* loose source route option */ | |
| optlist[1] = IPOPT_LSRR; | |
| - | i = lsrr * sizeof(gwlist[0]); |
| - | optlist[2] = i + 3; |
| + | size = lsrr * sizeof(gwlist[0]); |
| + | optlist[2] = size + 3; |
| /* pointer to LSRR addresses */ | |
| optlist[3] = IPOPT_MINOFF; | |
| - | memcpy(optlist + 4, gwlist, i); |
| + | memcpy(optlist + 4, gwlist, size); |
| if (setsockopt(sndsock, IPPROTO_IP, IP_OPTIONS, | |
| - | (char *)optlist, i + sizeof(gwlist[0])) < 0) { |
| + | (char *)optlist, size + sizeof(gwlist[0])) < 0) { |
| bb_perror_msg_and_die("IP_OPTIONS"); | |
| } | |
| } | |
| @@ -1103,28 +1108,34 @@ common_traceroute_main(int op, char **argv) | |
| int unreachable = 0; /* counter */ | |
| int gotlastaddr = 0; /* flags */ | |
| int got_there = 0; | |
| - | int first = 1; |
| printf("%2d", ttl); | |
| for (probe = 0; probe < nprobes; ++probe) { | |
| int read_len; | |
| unsigned t1; | |
| unsigned t2; | |
| + | int left_ms; |
| struct ip *ip; | |
| - | if (!first && pausemsecs > 0) |
| - | usleep(pausemsecs * 1000); |
| fflush_all(); | |
| + | if (probe != 0 && pausemsecs > 0) |
| + | usleep(pausemsecs * 1000); |
| - | t1 = monotonic_us(); |
| send_probe(++seq, ttl); | |
| + | t2 = t1 = monotonic_us(); |
| + | |
| + | left_ms = waittime * 1000; |
| + | while ((read_len = wait_for_reply(from_lsa, to, &t2, &left_ms)) != 0) { |
| + | int icmp_code; |
| + | |
| + | /* Recv'ed a packet, or read error */ |
| + | /* t2 = monotonic_us() - set by wait_for_reply */ |
| - | first = 0; |
| - | while ((read_len = wait_for_reply(from_lsa, to)) != 0) { |
| - | t2 = monotonic_us(); |
| - | i = packet_ok(read_len, from_lsa, to, seq); |
| + | if (read_len < 0) |
| + | continue; |
| + | icmp_code = packet_ok(read_len, from_lsa, to, seq); |
| /* Skip short packet */ | |
| - | if (i == 0) |
| + | if (icmp_code == 0) |
| continue; | |
| if (!gotlastaddr | |
| @@ -1143,10 +1154,10 @@ common_traceroute_main(int op, char **argv) | |
| printf(" (%d)", ip->ip_ttl); | |
| /* time exceeded in transit */ | |
| - | if (i == -1) |
| + | if (icmp_code == -1) |
| break; | |
| - | i--; |
| - | switch (i) { |
| + | icmp_code--; |
| + | switch (icmp_code) { |
| #if ENABLE_TRACEROUTE6 | |
| case ICMP6_DST_UNREACH_NOPORT << 8: | |
| got_there = 1; | |
| @@ -1219,16 +1230,18 @@ common_traceroute_main(int op, char **argv) | |
| ++unreachable; | |
| break; | |
| default: | |
| - | printf(" !<%d>", i); |
| + | printf(" !<%d>", icmp_code); |
| ++unreachable; | |
| break; | |
| } | |
| break; | |
| - | } |
| + | } /* while (wait and read a packet) */ |
| + | |
| /* there was no packet at all? */ | |
| if (read_len == 0) | |
| printf(" *"); | |
| - | } |
| + | } /* for (nprobes) */ |
| + | |
| bb_putchar('\n'); | |
| if (got_there | |
| || (unreachable > 0 && unreachable >= nprobes - 1) | |