On 2011/04/05 16:51, Stuart Henderson wrote: > if -t is used, display a notice when the TOS changes en-route. > ok?
oh, it's better with a (contrived) example: $ traceroute -nt 7 naiad traceroute to naiad.spacehopper.org (195.95.187.35), 64 hops max, 40 byte packets 1 85.158.44.145 0.441 ms (TOS=33!) 0.328 ms 0.396 ms 2 193.178.223.245 14.637 ms 15.213 ms 15.466 ms 3 194.39.143.145 16.600 ms 15.468 ms 16.206 ms 4 194.39.143.205 16.483 ms 16.210 ms 15.843 ms 5 193.203.5.182 17.475 ms 16.708 ms 16.986 ms 6 195.95.187.248 17.211 ms (TOS=4!) 16.460 ms 16.468 ms 7 195.95.187.35 27.99 ms 16.207 ms 17.467 ms > Index: traceroute.8 > =================================================================== > RCS file: /cvs/src/usr.sbin/traceroute/traceroute.8,v > retrieving revision 1.44 > diff -u -p -r1.44 traceroute.8 > --- traceroute.8 8 Jul 2010 20:23:03 -0000 1.44 > +++ traceroute.8 5 Apr 2011 15:50:38 -0000 > @@ -177,6 +177,8 @@ in probe packets to the following value > The value must be a decimal integer in the range 0 to 255. > This option can be used to > see if different types-of-service result in different paths. > +If this option is used, changes to the type-of-service in the > +returned packets are displayed. > (If you are not running a > .Bx 4.3 tahoe > or later system, this may be academic since the normal network > @@ -384,6 +386,8 @@ ever occur and the associated gateway is > (destination network or host unreachable for TOS), > .Sy !<code> > (other ICMP unreachable code). > +.Sy TOS=xxx > +(TOS bit in returned packet differs from last hop). > If almost all the probes result in some kind of unreachable, > .Nm > will give up and exit. > Index: traceroute.c > =================================================================== > RCS file: /cvs/src/usr.sbin/traceroute/traceroute.c,v > retrieving revision 1.74 > diff -u -p -r1.74 traceroute.c > --- traceroute.c 22 Mar 2011 10:16:23 -0000 1.74 > +++ traceroute.c 5 Apr 2011 15:50:38 -0000 > @@ -293,11 +293,13 @@ main(int argc, char *argv[]) > int mib[4] = { CTL_NET, PF_INET, IPPROTO_IP, IPCTL_DEFTTL }; > int ttl_flag = 0, incflag = 1, protoset = 0, sump = 0; > int ch, i, lsrr = 0, on = 1, probe, seq = 0, tos = 0; > + int last_tos, tos_returned; > size_t size = sizeof(max_ttl); > struct sockaddr_in from, to; > struct hostent *hp; > u_int32_t tmprnd; > - struct ip *ip; > + struct ip *ip, *inner_ip; > + struct icmp *icp; > u_int8_t ttl; > char *ep; > const char *errstr; > @@ -427,7 +429,7 @@ main(int argc, char *argv[]) > l = strtol(optarg, &ep, 10); > if (errno || !*optarg || *ep || l < 0 || l > 255) > errx(1, "tos must be 0 to 255."); > - tos = (int)l; > + last_tos = tos = (int)l; > break; > case 'v': > verbose++; > @@ -636,9 +638,21 @@ main(int argc, char *argv[]) > ++got_there; > break; > } > + > + icp = (struct icmp *) (((u_char > *)ip)+(ip->ip_hl<<2)); > + inner_ip = (struct ip *) (((u_char *)icp)+8); > + > + tos_returned = inner_ip->ip_tos; > + > + if (tos_returned != last_tos) > + printf (" (TOS=%d!)", tos_returned); > + > + last_tos = tos_returned; > + > /* time exceeded in transit */ > if (i == -1) > break; > + > code = i - 1; > switch (code) { > case ICMP_UNREACH_PORT: