Only notify userland about resolved ARP entries if the Ethernet address

changed or if we asked for it.

Should reduce the RTM_RESOLVE storm seeing by claudio@

With inputs from and ok mikeb@

diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index 4f70ce6..0145883 100644 (file)
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_ether.c,v 1.140 2015/01/08 14:29:18 mpi Exp $      */
+/*     $OpenBSD: if_ether.c,v 1.141 2015/01/13 12:16:18 mpi Exp $      */
 /*     $NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft Exp $    */
 
 /*
@@ -560,7 +560,7 @@ in_arpinput(struct mbuf *m)
        u_int8_t *ether_shost = NULL;
 #endif
        char addr[INET_ADDRSTRLEN];
-       int op;
+       int op, changed = 0;
 
        ea = mtod(m, struct ether_arp *);
        op = ntohs(ea->arp_op);
@@ -684,6 +684,7 @@ in_arpinput(struct mbuf *m)
                                   ac->ac_if.if_xname);
                                rt->rt_expire = 1; /* no longer static */
                        }
+                       changed = 1;
                    }
                } else if (rt->rt_ifp != &ac->ac_if &&
 #if NBRIDGE > 0
@@ -711,8 +712,10 @@ in_arpinput(struct mbuf *m)
                if (rt->rt_expire)
                        rt->rt_expire = time_second + arpt_keep;
                rt->rt_flags &= ~RTF_REJECT;
+               /* Notify userland that an ARP resolution has been done. */
+               if (la->la_asked || changed)
+                       rt_sendmsg(rt, RTM_RESOLVE, rt->rt_ifp->if_rdomain);
                la->la_asked = 0;
-               rt_sendmsg(rt, RTM_RESOLVE, rt->rt_ifp->if_rdomain);
                while ((mh = la->la_hold_head) != NULL) {
                        if ((la->la_hold_head = mh->m_nextpkt) == NULL)
                                la->la_hold_tail = NULL;