Messages in this thread |  | | Date | Wed, 6 Dec 2000 17:27:10 +0100 | From | Andi Kleen <> | Subject | Re: Traceroute without s bit |
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On Wed, Dec 06, 2000 at 04:07:38PM +0100, Olaf Kirch wrote: > On Wed, Dec 06, 2000 at 02:09:05PM +0100, Andi Kleen wrote: > > IP_PKTINFO does not allow to set source addresses, only destination > > addresses. Source address depends on the boundage or the route. > > No. At least udp_sendmsg uses the spec_dst_addr field as the source > address. I added some code to my traceroute that lets you select the > source address in order to verify that.
Please read the code again.
It uses spec_dst to select the possibly policy sourced route -- the actual source address is only set from that route (either default or what was set using ip route's from flag) or the bound address.
> However the good thing is that somewhere something seems to check that > the requested address is indeed one attached to a local interface.
That's not actually checked, but in most simple routing configurations it is true.
> > > > 13:43:02 poll([{fd=4, events=POLLERR}], 1, 5) = 0 > > > 13:43:02 poll([{fd=4, events=POLLERR}], 1, 5) = 0 > > > 13:43:02 poll([{fd=4, events=POLLERR}], 1, 5) = 0 > > > 13:43:02 poll([{fd=4, events=POLLERR}], 1, 5) = 0 > > > > POLLERR is returned until the error queue is empty. I suspect you're > > not emptying it properly in all cases. It can contain multiple errors. > > But it doesn't return POLLERR. If it was returning it, pollfd.revents > would be set. pollfd.events is the event mask that's being passed _into_ > the poll() call.
Right. I missed your 5ms timeout @)
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