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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: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2011-03-24 17:42:21 -07:00
parent f7594d4294
commit 436c3b66ec
5 changed files with 33 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/net/ip_fib.h
View File

@ -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;

1
include/net/netns/ipv4.h
View File

@ -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

11
net/ipv4/fib_frontend.c
View File

@ -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:

32
net/ipv4/fib_semantics.c
View File

@ -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 @@ out:
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
/*

6
net/ipv4/route.c
View File

@ -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;
}