Self pointing routes are installed for configured interface addresses

and address aliases. After an interface is brought down and brought
back up again, those self pointing routes disappeared. This patch
ensures after an interface is brought back up, the loopback routes
are reinstalled properly.

Reviewed by:	bz
MFC after:	immediately

2 files changed, 56 insertions, 0 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 36c0d03..c0ff443 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1414,6 +1414,59 @@ ifa_free(struct ifaddr *ifa)
 	}
 }
 
+int
+ifa_add_loopback_route(struct ifaddr *ifa, struct sockaddr *ia)
+{
+	int error = 0;
+	struct rtentry *rt = NULL;
+	struct rt_addrinfo info;
+	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
+
+	bzero(&info, sizeof(info));
+	info.rti_ifp = V_loif;
+	info.rti_flags = ifa->ifa_flags | RTF_HOST | RTF_STATIC;
+	info.rti_info[RTAX_DST] = ia;
+	info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&null_sdl;
+	error = rtrequest1_fib(RTM_ADD, &info, &rt, 0);
+
+	if (error == 0 && rt != NULL) {
+		RT_LOCK(rt);
+		((struct sockaddr_dl *)rt->rt_gateway)->sdl_type  =
+			rt->rt_ifp->if_type;
+		((struct sockaddr_dl *)rt->rt_gateway)->sdl_index =
+			rt->rt_ifp->if_index;
+		RT_REMREF(rt);
+		RT_UNLOCK(rt);
+	} else if (error != 0)
+		log(LOG_INFO, "ifa_add_loopback_route: insertion failed\n");
+
+	return (error);
+}
+
+int
+ifa_del_loopback_route(struct ifaddr *ifa, struct sockaddr *ia)
+{
+	int error = 0;
+	struct rt_addrinfo info;
+	struct sockaddr_dl null_sdl;
+
+	bzero(&null_sdl, sizeof(null_sdl));
+	null_sdl.sdl_len = sizeof(null_sdl);
+	null_sdl.sdl_family = AF_LINK;
+	null_sdl.sdl_type = ifa->ifa_ifp->if_type;
+	null_sdl.sdl_index = ifa->ifa_ifp->if_index;
+	bzero(&info, sizeof(info));
+	info.rti_flags = ifa->ifa_flags | RTF_HOST | RTF_STATIC;
+	info.rti_info[RTAX_DST] = ia;
+	info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&null_sdl;
+	error = rtrequest1_fib(RTM_DELETE, &info, NULL, 0);
+
+	if (error != 0)
+		log(LOG_INFO, "ifa_del_loopback_route: deletion failed\n");
+
+	return (error);
+}
+
 /*
  * XXX: Because sockaddr_dl has deeper structure than the sockaddr
  * structs used to represent other address families, it is necessary
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 3ab6208..523b9e8 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -854,6 +854,9 @@ struct	ifnet *ifunit_ref(const char *);
 void	ifq_init(struct ifaltq *, struct ifnet *ifp);
 void	ifq_delete(struct ifaltq *);
 
+int	ifa_add_loopback_route(struct ifaddr *, struct sockaddr *);
+int	ifa_del_loopback_route(struct ifaddr *, struct sockaddr *);
+
 struct	ifaddr *ifa_ifwithaddr(struct sockaddr *);
 int		ifa_ifwithaddr_check(struct sockaddr *);
 struct	ifaddr *ifa_ifwithbroadaddr(struct sockaddr *);