Claudio Jeker(cje...@diehard.n-r-g.com) on 2018.07.06 07:44:43 +0200:
> On Thu, Jul 05, 2018 at 10:51:24PM +0100, Stuart Henderson wrote:
> > I noticed relatively high cpu use from slaacd on a BGP router
> > that was undergoing some route churn earlier (no interfaces were
> > actually configured to use slaac).
> >
> > routesock is currently unfiltered so will see a lot of messages,
> > frontend_routesock is filtered but will still see all RTM_DELETE
> > which will be noticeable during churn.
> >
> > Seems that we may be able to restrict these to inet6 (kernel comment
> > is, "If route socket is bound to an address family only send messages
> > that match the address family. Address family agnostic messages are
> > always sent.") Does this make sense or am I missing something about
> > the messages needed by slaacd?
> >
>
> In my opinion this is the right thing to do.
> RTM_IFINFO is always sent, RTM_NEWADDR and RTM_DELADDR will be filtered
> based on the address family as is RTM_DELETE. Those should be fine.
> My question mark is about RTM_PROPOSAL. Does slaacd need to see dhclient
> RTM_PROPOSAL messages? Looking at the code it does not seem like that is
> the case.
well, if the ideas around RTM_PROPOSAL, ie networkd ever come to fruition,
its going to send and receive(?) RTM_PROPOSAL.
I dont know if it even needs to see all messages of AF_INET6 on the
routesock. If not, maybe it could also use the prio filter here.
> Also it seems routesock is never read so it should be
> shutdown(routesock, SHUT_RD);
>
> OK claudio@ (which is not much worth when it comes to AF_INET6 :))
come to the dark side, we have cookies (and more ip addresses).
ok benno@, but maybe wait until florian can respond.
> >
> > Index: slaacd.c
> > ===================================================================
> > RCS file: /cvs/src/sbin/slaacd/slaacd.c,v
> > retrieving revision 1.23
> > diff -u -p -u -7 -r1.23 slaacd.c
> > --- slaacd.c 18 Jun 2018 16:13:45 -0000 1.23
> > +++ slaacd.c 5 Jul 2018 21:44:38 -0000
> > @@ -240,15 +240,15 @@ main(int argc, char *argv[])
> > pipe_main2frontend[1], debug, verbose);
> >
> > slaacd_process = PROC_MAIN;
> >
> > log_procinit(log_procnames[slaacd_process]);
> >
> > if ((routesock = socket(PF_ROUTE, SOCK_RAW | SOCK_CLOEXEC |
> > - SOCK_NONBLOCK, 0)) < 0)
> > + SOCK_NONBLOCK, AF_INET6)) < 0)
> > fatal("route socket");
> >
> > event_init();
> >
> > /* Setup signal handler. */
> > signal_set(&ev_sigint, SIGINT, main_sig_handler, NULL);
> > signal_set(&ev_sigterm, SIGTERM, main_sig_handler, NULL);
> > @@ -300,16 +300,16 @@ main(int argc, char *argv[])
> > /* only router advertisements */
> > ICMP6_FILTER_SETBLOCKALL(&filt);
> > ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
> > if (setsockopt(icmp6sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
> > sizeof(filt)) == -1)
> > fatal("ICMP6_FILTER");
> >
> > - if ((frontend_routesock = socket(PF_ROUTE, SOCK_RAW | SOCK_CLOEXEC, 0))
> > - < 0)
> > + if ((frontend_routesock = socket(PF_ROUTE, SOCK_RAW | SOCK_CLOEXEC,
> > + AF_INET6)) < 0)
> > fatal("route socket");
> >
> > rtfilter = ROUTE_FILTER(RTM_IFINFO) | ROUTE_FILTER(RTM_NEWADDR) |
> > ROUTE_FILTER(RTM_DELADDR) | ROUTE_FILTER(RTM_PROPOSAL) |
> > ROUTE_FILTER(RTM_DELETE);
> > if (setsockopt(frontend_routesock, PF_ROUTE, ROUTE_MSGFILTER,
> > &rtfilter, sizeof(rtfilter)) < 0)
> >
>
> --
> :wq Claudio
>
