ipv4: Properly purge netdev references on uncached routes.

When a device is unregistered, we have to purge all of the
references to it that may exist in the entire system.

If a route is uncached, we currently have no way of accomplishing
this.

So create a global list that is scanned when a network device goes
down.  This mirrors the logic in net/core/dst.c's dst_ifdown().

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/route.h b/include/net/route.h
index 8c52bc6..776a27f 100644 (file)
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -57,6 +57,8 @@ struct rtable {
 
        /* Miscellaneous cached information */
        u32                     rt_pmtu;
+
+       struct list_head        rt_uncached;
 };
 
 static inline bool rt_is_input_route(const struct rtable *rt)
@@ -107,6 +109,7 @@ extern struct ip_rt_acct __percpu *ip_rt_acct;
 struct in_device;
 extern int             ip_rt_init(void);
 extern void            rt_cache_flush(struct net *net, int how);
+extern void            rt_flush_dev(struct net_device *dev);
 extern struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
 extern struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
                                           struct sock *sk);

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 8732cc7..c43ae3f 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1046,6 +1046,7 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
 
        if (event == NETDEV_UNREGISTER) {
                fib_disable_ip(dev, 2, -1);
+               rt_flush_dev(dev);
                return NOTIFY_DONE;
        }
 

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b102eeb..c035251 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -147,6 +147,7 @@ static void          ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
                                           struct sk_buff *skb, u32 mtu);
 static void             ip_do_redirect(struct dst_entry *dst, struct sock *sk,
                                        struct sk_buff *skb);
+static void            ipv4_dst_destroy(struct dst_entry *dst);
 
 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
                            int how)
@@ -170,6 +171,7 @@ static struct dst_ops ipv4_dst_ops = {
        .default_advmss =       ipv4_default_advmss,
        .mtu =                  ipv4_mtu,
        .cow_metrics =          ipv4_cow_metrics,
+       .destroy =              ipv4_dst_destroy,
        .ifdown =               ipv4_dst_ifdown,
        .negative_advice =      ipv4_negative_advice,
        .link_failure =         ipv4_link_failure,
@@ -1175,9 +1177,11 @@ static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
        return NULL;
 }
 
-static void rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
+static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
                              __be32 daddr)
 {
+       bool ret = false;
+
        spin_lock_bh(&fnhe_lock);
 
        if (daddr == fnhe->fnhe_daddr) {
@@ -1203,6 +1207,7 @@ static void rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
                        rt_free(orig);
 
                fnhe->fnhe_stamp = jiffies;
+               ret = true;
        } else {
                /* Routes we intend to cache in nexthop exception have
                 * the DST_NOCACHE bit clear.  However, if we are
@@ -1212,11 +1217,14 @@ static void rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
                rt->dst.flags |= DST_NOCACHE;
        }
        spin_unlock_bh(&fnhe_lock);
+
+       return ret;
 }
 
-static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
+static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
 {
        struct rtable *orig, *prev, **p;
+       bool ret = true;
 
        if (rt_is_input_route(rt)) {
                p = (struct rtable **)&nh->nh_rth_input;
@@ -1239,6 +1247,48 @@ static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
                 */
 nocache:
                rt->dst.flags |= DST_NOCACHE;
+               ret = false;
+       }
+
+       return ret;
+}
+
+static DEFINE_SPINLOCK(rt_uncached_lock);
+static LIST_HEAD(rt_uncached_list);
+
+static void rt_add_uncached_list(struct rtable *rt)
+{
+       spin_lock_bh(&rt_uncached_lock);
+       list_add_tail(&rt->rt_uncached, &rt_uncached_list);
+       spin_unlock_bh(&rt_uncached_lock);
+}
+
+static void ipv4_dst_destroy(struct dst_entry *dst)
+{
+       struct rtable *rt = (struct rtable *) dst;
+
+       if (dst->flags & DST_NOCACHE) {
+               spin_lock_bh(&rt_uncached_lock);
+               list_del(&rt->rt_uncached);
+               spin_unlock_bh(&rt_uncached_lock);
+       }
+}
+
+void rt_flush_dev(struct net_device *dev)
+{
+       if (!list_empty(&rt_uncached_list)) {
+               struct net *net = dev_net(dev);
+               struct rtable *rt;
+
+               spin_lock_bh(&rt_uncached_lock);
+               list_for_each_entry(rt, &rt_uncached_list, rt_uncached) {
+                       if (rt->dst.dev != dev)
+                               continue;
+                       rt->dst.dev = net->loopback_dev;
+                       dev_hold(rt->dst.dev);
+                       dev_put(dev);
+               }
+               spin_unlock_bh(&rt_uncached_lock);
        }
 }
 
@@ -1254,6 +1304,8 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
                           struct fib_nh_exception *fnhe,
                           struct fib_info *fi, u16 type, u32 itag)
 {
+       bool cached = false;
+
        if (fi) {
                struct fib_nh *nh = &FIB_RES_NH(*res);
 
@@ -1264,10 +1316,12 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
                rt->dst.tclassid = nh->nh_tclassid;
 #endif
                if (unlikely(fnhe))
-                       rt_bind_exception(rt, fnhe, daddr);
+                       cached = rt_bind_exception(rt, fnhe, daddr);
                else if (!(rt->dst.flags & DST_NOCACHE))
-                       rt_cache_route(nh, rt);
+                       cached = rt_cache_route(nh, rt);
        }
+       if (unlikely(!cached))
+               rt_add_uncached_list(rt);
 
 #ifdef CONFIG_IP_ROUTE_CLASSID
 #ifdef CONFIG_IP_MULTIPLE_TABLES
@@ -1334,6 +1388,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        rth->rt_iif     = 0;
        rth->rt_pmtu    = 0;
        rth->rt_gateway = 0;
+       INIT_LIST_HEAD(&rth->rt_uncached);
        if (our) {
                rth->dst.input= ip_local_deliver;
                rth->rt_flags |= RTCF_LOCAL;
@@ -1459,6 +1514,7 @@ static int __mkroute_input(struct sk_buff *skb,
        rth->rt_iif     = 0;
        rth->rt_pmtu    = 0;
        rth->rt_gateway = 0;
+       INIT_LIST_HEAD(&rth->rt_uncached);
 
        rth->dst.input = ip_forward;
        rth->dst.output = ip_output;
@@ -1625,6 +1681,7 @@ local_input:
        rth->rt_iif     = 0;
        rth->rt_pmtu    = 0;
        rth->rt_gateway = 0;
+       INIT_LIST_HEAD(&rth->rt_uncached);
        if (res.type == RTN_UNREACHABLE) {
                rth->dst.input= ip_error;
                rth->dst.error= -err;
@@ -1792,6 +1849,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
        rth->rt_iif     = orig_oif ? : 0;
        rth->rt_pmtu    = 0;
        rth->rt_gateway = 0;
+       INIT_LIST_HEAD(&rth->rt_uncached);
 
        RT_CACHE_STAT_INC(out_slow_tot);
 
@@ -2071,6 +2129,8 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
                rt->rt_type = ort->rt_type;
                rt->rt_gateway = ort->rt_gateway;
 
+               INIT_LIST_HEAD(&rt->rt_uncached);
+
                dst_free(new);
        }
 

diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index c628184..681ea2f 100644 (file)
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -92,6 +92,7 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
        xdst->u.rt.rt_type = rt->rt_type;
        xdst->u.rt.rt_gateway = rt->rt_gateway;
        xdst->u.rt.rt_pmtu = rt->rt_pmtu;
+       INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
 
        return 0;
 }