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Commit 436c3b66 authored by David S. Miller's avatar David S. Miller
Browse files

ipv4: Invalidate nexthop cache nh_saddr more correctly. 



Any operation that:

1) Brings up an interface
2) Adds an IP address to an interface
3) Deletes an IP address from an interface

can potentially invalidate the nh_saddr value, requiring
it to be recomputed.

Perform the recomputation lazily using a generation ID.

Reported-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f7594d42

include/net/ip_fib.h

+10 −2
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct fib_nh { 
	int			nh_oif;

	__be32			nh_gw;

	__be32			nh_saddr;

	int			nh_saddr_genid;

};



/*
@@ -141,12 +142,19 @@ struct fib_result_nl { 


#endif /* CONFIG_IP_ROUTE_MULTIPATH */



#define FIB_RES_SADDR(res)		(FIB_RES_NH(res).nh_saddr)

extern __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh);



#define FIB_RES_SADDR(net, res)				\

	((FIB_RES_NH(res).nh_saddr_genid ==		\

	  atomic_read(&(net)->ipv4.dev_addr_genid)) ?	\

	 FIB_RES_NH(res).nh_saddr :			\

	 fib_info_update_nh_saddr((net), &FIB_RES_NH(res)))

#define FIB_RES_GW(res)			(FIB_RES_NH(res).nh_gw)

#define FIB_RES_DEV(res)		(FIB_RES_NH(res).nh_dev)

#define FIB_RES_OIF(res)		(FIB_RES_NH(res).nh_oif)



#define FIB_RES_PREFSRC(res)		((res).fi->fib_prefsrc ? : FIB_RES_SADDR(res))

#define FIB_RES_PREFSRC(net, res)	((res).fi->fib_prefsrc ? : \

					 FIB_RES_SADDR(net, res))



struct fib_table {

	struct hlist_node tb_hlist;

include/net/netns/ipv4.h

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ struct netns_ipv4 { 
	int current_rt_cache_rebuild_count;



	atomic_t rt_genid;

	atomic_t dev_addr_genid;



#ifdef CONFIG_IP_MROUTE

#ifndef CONFIG_IP_MROUTE_MULTIPLE_TABLES

net/ipv4/fib_frontend.c

+7 −4
Original line number Diff line number Diff line
@@ -228,7 +228,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, 
		if (res.type != RTN_LOCAL || !accept_local)

			goto e_inval;

	}

	*spec_dst = FIB_RES_PREFSRC(res);

	*spec_dst = FIB_RES_PREFSRC(net, res);

	fib_combine_itag(itag, &res);

	dev_match = false;
@@ -258,7 +258,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, 
	ret = 0;

	if (fib_lookup(net, &fl4, &res) == 0) {

		if (res.type == RTN_UNICAST) {

			*spec_dst = FIB_RES_PREFSRC(res);

			*spec_dst = FIB_RES_PREFSRC(net, res);

			ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;

		}

	}
@@ -960,6 +960,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, 
{

	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;

	struct net_device *dev = ifa->ifa_dev->dev;

	struct net *net = dev_net(dev);



	switch (event) {

	case NETDEV_UP:
@@ -967,12 +968,12 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, 
#ifdef CONFIG_IP_ROUTE_MULTIPATH

		fib_sync_up(dev);

#endif

		fib_update_nh_saddrs(dev);

		atomic_inc(&net->ipv4.dev_addr_genid);

		rt_cache_flush(dev_net(dev), -1);

		break;

	case NETDEV_DOWN:

		fib_del_ifaddr(ifa, NULL);

		fib_update_nh_saddrs(dev);

		atomic_inc(&net->ipv4.dev_addr_genid);

		if (ifa->ifa_dev->ifa_list == NULL) {

			/* Last address was deleted from this interface.

			 * Disable IP.
@@ -990,6 +991,7 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo 
{

	struct net_device *dev = ptr;

	struct in_device *in_dev = __in_dev_get_rtnl(dev);

	struct net *net = dev_net(dev);



	if (event == NETDEV_UNREGISTER) {

		fib_disable_ip(dev, 2, -1);
@@ -1007,6 +1009,7 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo 
#ifdef CONFIG_IP_ROUTE_MULTIPATH

		fib_sync_up(dev);

#endif

		atomic_inc(&net->ipv4.dev_addr_genid);

		rt_cache_flush(dev_net(dev), -1);

		break;

	case NETDEV_DOWN:

net/ipv4/fib_semantics.c

+11 −21
Original line number Diff line number Diff line
@@ -695,6 +695,16 @@ static void fib_info_hash_move(struct hlist_head *new_info_hash, 
	fib_info_hash_free(old_laddrhash, bytes);

}



__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)

{

	nh->nh_saddr = inet_select_addr(nh->nh_dev,

					nh->nh_gw,

					nh->nh_cfg_scope);

	nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);



	return nh->nh_saddr;

}



struct fib_info *fib_create_info(struct fib_config *cfg)

{

	int err;
@@ -855,9 +865,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg) 


	change_nexthops(fi) {

		nexthop_nh->nh_cfg_scope = cfg->fc_scope;

		nexthop_nh->nh_saddr = inet_select_addr(nexthop_nh->nh_dev,

							nexthop_nh->nh_gw,

							nexthop_nh->nh_cfg_scope);

		fib_info_update_nh_saddr(net, nexthop_nh);

	} endfor_nexthops(fi)



link_it:
@@ -1128,24 +1136,6 @@ void fib_select_default(struct fib_result *res) 
	return;

}



void fib_update_nh_saddrs(struct net_device *dev)

{

	struct hlist_head *head;

	struct hlist_node *node;

	struct fib_nh *nh;

	unsigned int hash;



	hash = fib_devindex_hashfn(dev->ifindex);

	head = &fib_info_devhash[hash];

	hlist_for_each_entry(nh, node, head, nh_hash) {

		if (nh->nh_dev != dev)

			continue;

		nh->nh_saddr = inet_select_addr(nh->nh_dev,

						nh->nh_gw,

						nh->nh_cfg_scope);

	}

}



#ifdef CONFIG_IP_ROUTE_MULTIPATH



/*

net/ipv4/route.c

+4 −2
Original line number Diff line number Diff line
@@ -1718,7 +1718,7 @@ void ip_rt_get_source(u8 *addr, struct rtable *rt) 


		rcu_read_lock();

		if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)

			src = FIB_RES_PREFSRC(res);

			src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);

		else

			src = inet_select_addr(rt->dst.dev, rt->rt_gateway,

					RT_SCOPE_UNIVERSE);
@@ -2615,7 +2615,7 @@ static struct rtable *ip_route_output_slow(struct net *net, 
		fib_select_default(&res);



	if (!fl4.saddr)

		fl4.saddr = FIB_RES_PREFSRC(res);

		fl4.saddr = FIB_RES_PREFSRC(net, res);



	dev_out = FIB_RES_DEV(res);

	fl4.flowi4_oif = dev_out->ifindex;
@@ -3219,6 +3219,8 @@ static __net_init int rt_genid_init(struct net *net) 
{

	get_random_bytes(&net->ipv4.rt_genid,

			 sizeof(net->ipv4.rt_genid));

	get_random_bytes(&net->ipv4.dev_addr_genid,

			 sizeof(net->ipv4.dev_addr_genid));

	return 0;

}