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Date: Tue, 31 Jul 2012 15:20:33 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH 2/2] 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@...emloft.net>
---
This is just a respin of what I posted the other day, against Eric's
fixes of today. Pushed to 'net'.
diff --git a/include/net/route.h b/include/net/route.h
index 8c52bc6..776a27f 100644
--- 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
--- 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
--- 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
--- 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;
}
--
1.7.10.4
--
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