ospfd: use ROUTE_FLAGFILTER

[Jonathan Matthew]

ospfd is our first target for using ROUTE_FLAGFILTER to reduce pressure on the
route socket, so here's the diff we've been running for a couple of weeks now
(minus the fix for RTM_DELETE flags, notably).

ok?

Index: kroute.c
===================================================================
RCS file: /cvs/src/usr.sbin/ospfd/kroute.c,v
retrieving revision 1.113
diff -u -p -r1.113 kroute.c
--- kroute.c    9 Nov 2019 15:54:19 -0000       1.113
+++ kroute.c    27 Jul 2020 03:45:41 -0000
@@ -133,6 +133,7 @@ kr_init(int fs, u_int rdomain, int redis
        int             opt = 0, rcvbuf, default_rcvbuf;
        socklen_t       optlen;
        int             filter_prio = fib_prio;
+       int             filter_flags = RTF_LLINFO | RTF_BROADCAST;
 
        kr_state.fib_sync = fs;
        kr_state.rdomain = rdomain;
@@ -158,6 +159,11 @@ kr_init(int fs, u_int rdomain, int redis
        if (setsockopt(kr_state.fd, AF_ROUTE, ROUTE_PRIOFILTER, &filter_prio,
            sizeof(filter_prio)) == -1) {
                log_warn("%s: setsockopt AF_ROUTE ROUTE_PRIOFILTER", __func__);
+               /* not fatal */
+       }
+       if (setsockopt(kr_state.fd, AF_ROUTE, ROUTE_FLAGFILTER, &filter_flags,
+           sizeof(filter_flags)) == -1) {
+               log_warn("%s: setsockopt AF_ROUTE ROUTE_FLAGFILTER", __func__);
                /* not fatal */
        }