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Commit caacf05e authored by David S. Miller's avatar David S. Miller
Browse files

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: default avatarDavid S. Miller <davem@davemloft.net>
parent c5038a83

include/net/route.h

+3 −0
Original line number Diff line number Diff line
@@ -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);

net/ipv4/fib_frontend.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

	}

net/ipv4/route.c

+64 −4
Original line number Diff line number Diff line
@@ -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 @@ out: return err; 
	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);

	}

net/ipv4/xfrm4_policy.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

}