Using a normaly unavailable 0.0.0.1 gateway on routes on sppp(4) based

devices is a bad idea. The problem is that the default route per se works
but PMTU is unable to clone host routes because the gateway is unreachable.
Fix sppp(4) so that it walks the routing table and fixes the gateways.
This makes PMTU work again. Diff tested by weerd@ and markus@ (older version)
for a long time.

1 files changed, 39 insertions, 1 deletions

diff --git a/sys/net/if_spppsubr.c b/sys/net/if_spppsubr.c
index 69ee2eeeec2..13931a8ca4a 100644
--- a/sys/net/if_spppsubr.c
+++ b/sys/net/if_spppsubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_spppsubr.c,v 1.81 2010/07/20 15:36:03 matthew Exp $	*/
+/*	$OpenBSD: if_spppsubr.c,v 1.82 2010/09/13 08:53:06 claudio Exp $	*/
 /*
  * Synchronous PPP/Cisco link level subroutines.
  * Keepalive protocol implemented in both Cisco and PPP modes.
@@ -408,6 +408,8 @@ HIDE void sppp_phase_network(struct sppp *sp);
 HIDE void sppp_print_bytes(const u_char *p, u_short len);
 HIDE void sppp_print_string(const char *p, u_short len);
 HIDE void sppp_qflush(struct ifqueue *ifq);
+int sppp_update_gw_walker(struct radix_node *rn, void *arg, u_int);
+void sppp_update_gw(struct ifnet *ifp);
 HIDE void sppp_set_ip_addrs(struct sppp *sp, u_int32_t myaddr,
 			      u_int32_t hisaddr);
 HIDE void sppp_clear_ip_addrs(struct sppp *sp);
@@ -4653,6 +4655,39 @@ sppp_get_ip_addrs(struct sppp *sp, u_int32_t *src, u_int32_t *dst,
 	if (src) *src = ntohl(ssrc);
 }
 
+int
+sppp_update_gw_walker(struct radix_node *rn, void *arg, u_int id)
+{
+	struct ifnet *ifp = arg;
+	struct rtentry *rt = (struct rtentry *)rn;
+
+	if (rt->rt_ifp == ifp) {
+		if (rt->rt_ifa->ifa_dstaddr->sa_family !=
+		    rt->rt_gateway->sa_family ||
+		    (rt->rt_flags & RTF_GATEWAY) == 0)
+			return (0);	/* do not modify non-gateway routes */
+		bcopy(rt->rt_ifa->ifa_dstaddr, rt->rt_gateway,
+		    rt->rt_ifa->ifa_dstaddr->sa_len);
+	}
+	return (0);
+}
+
+void
+sppp_update_gw(struct ifnet *ifp)
+{
+        struct radix_node_head *rnh;
+	u_int tid;
+
+	/* update routing table */
+	for (tid = 0; tid <= RT_TABLEID_MAX; tid++) {
+		if ((rnh = rt_gettable(AF_INET, tid)) != NULL) {
+			while ((*rnh->rnh_walktree)(rnh,
+			    sppp_update_gw_walker, ifp) == EAGAIN)
+				;	/* nothing */
+		}
+	}
+}
+
 /*
  * If an address is 0, leave it the way it is.
  */
@@ -4713,7 +4748,9 @@ sppp_set_ip_addrs(struct sppp *sp, u_int32_t myaddr, u_int32_t hisaddr)
 		if (debug && error) {
 			log(LOG_DEBUG, SPP_FMT "sppp_set_ip_addrs: in_ifinit "
 			" failed, error=%d\n", SPP_ARGS(ifp), error);
+			return;
 		}
+		sppp_update_gw(ifp);
 	}
 }
 
@@ -4760,6 +4797,7 @@ sppp_clear_ip_addrs(struct sppp *sp)
 			dest->sin_addr.s_addr = sp->ipcp.saved_hisaddr;
 		if (!in_ifinit(ifp, ifatoia(ifa), &new_sin, 0))
 			dohooks(ifp->if_addrhooks, 0);
+		sppp_update_gw(ifp);
 	}
 }