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Date: Mon, 15 Jun 2015 23:26:29 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 32/32] netfilter: nf_tables_netdev: unregister hooks on net_device removal
In case the net_device is gone, we have to unregister the hooks and put back
the reference on the net_device object. Once it comes back, register them
again. This also covers the device rename case.
This patch also adds a new flag to indicate that the basechain is disabled, so
their hooks are not registered. This flag is used by the netdev family to
handle the case where the net_device object is gone. Currently this flag is not
exposed to userspace.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/nf_tables.h | 7 ++++
net/netfilter/nf_tables_api.c | 16 ++++++--
net/netfilter/nf_tables_netdev.c | 75 +++++++++++++++++++++++++++++++++++++
3 files changed, 94 insertions(+), 4 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 09d6f8d..2a24668 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -781,6 +781,7 @@ struct nft_stats {
};
#define NFT_HOOK_OPS_MAX 2
+#define NFT_BASECHAIN_DISABLED (1 << 0)
/**
* struct nft_base_chain - nf_tables base chain
@@ -798,6 +799,7 @@ struct nft_base_chain {
possible_net_t pnet;
const struct nf_chain_type *type;
u8 policy;
+ u8 flags;
struct nft_stats __percpu *stats;
struct nft_chain chain;
char dev_name[IFNAMSIZ];
@@ -808,6 +810,11 @@ static inline struct nft_base_chain *nft_base_chain(const struct nft_chain *chai
return container_of(chain, struct nft_base_chain, chain);
}
+int nft_register_basechain(struct nft_base_chain *basechain,
+ unsigned int hook_nops);
+void nft_unregister_basechain(struct nft_base_chain *basechain,
+ unsigned int hook_nops);
+
unsigned int nft_do_chain(struct nft_pktinfo *pkt,
const struct nf_hook_ops *ops);
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index c66dc62..cfe6368 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -127,17 +127,25 @@ static void nft_trans_destroy(struct nft_trans *trans)
kfree(trans);
}
-static int nft_register_basechain(struct nft_base_chain *basechain,
- unsigned int hook_nops)
+int nft_register_basechain(struct nft_base_chain *basechain,
+ unsigned int hook_nops)
{
+ if (basechain->flags & NFT_BASECHAIN_DISABLED)
+ return 0;
+
return nf_register_hooks(basechain->ops, hook_nops);
}
+EXPORT_SYMBOL_GPL(nft_register_basechain);
-static void nft_unregister_basechain(struct nft_base_chain *basechain,
- unsigned int hook_nops)
+void nft_unregister_basechain(struct nft_base_chain *basechain,
+ unsigned int hook_nops)
{
+ if (basechain->flags & NFT_BASECHAIN_DISABLED)
+ return;
+
nf_unregister_hooks(basechain->ops, hook_nops);
}
+EXPORT_SYMBOL_GPL(nft_unregister_basechain);
static int nf_tables_register_hooks(const struct nft_table *table,
struct nft_chain *chain,
diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c
index 04cb170..2cae4d4 100644
--- a/net/netfilter/nf_tables_netdev.c
+++ b/net/netfilter/nf_tables_netdev.c
@@ -8,6 +8,7 @@
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/netdevice.h>
#include <net/netfilter/nf_tables.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
@@ -157,6 +158,77 @@ static const struct nf_chain_type nft_filter_chain_netdev = {
.hook_mask = (1 << NF_NETDEV_INGRESS),
};
+static void nft_netdev_event(unsigned long event, struct nft_af_info *afi,
+ struct net_device *dev, struct nft_table *table,
+ struct nft_base_chain *basechain)
+{
+ switch (event) {
+ case NETDEV_REGISTER:
+ if (strcmp(basechain->dev_name, dev->name) != 0)
+ return;
+
+ BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED));
+
+ dev_hold(dev);
+ basechain->ops[0].dev = dev;
+ basechain->flags &= ~NFT_BASECHAIN_DISABLED;
+ if (!(table->flags & NFT_TABLE_F_DORMANT))
+ nft_register_basechain(basechain, afi->nops);
+ break;
+ case NETDEV_UNREGISTER:
+ if (strcmp(basechain->dev_name, dev->name) != 0)
+ return;
+
+ BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED);
+
+ if (!(table->flags & NFT_TABLE_F_DORMANT))
+ nft_unregister_basechain(basechain, afi->nops);
+
+ dev_put(basechain->ops[0].dev);
+ basechain->ops[0].dev = NULL;
+ basechain->flags |= NFT_BASECHAIN_DISABLED;
+ break;
+ case NETDEV_CHANGENAME:
+ if (dev->ifindex != basechain->ops[0].dev->ifindex)
+ return;
+
+ strncpy(basechain->dev_name, dev->name, IFNAMSIZ);
+ break;
+ }
+}
+
+static int nf_tables_netdev_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct nft_af_info *afi;
+ struct nft_table *table;
+ struct nft_chain *chain;
+
+ nfnl_lock(NFNL_SUBSYS_NFTABLES);
+ list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) {
+ if (afi->family != NFPROTO_NETDEV)
+ continue;
+
+ list_for_each_entry(table, &afi->tables, list) {
+ list_for_each_entry(chain, &table->chains, list) {
+ if (!(chain->flags & NFT_BASE_CHAIN))
+ continue;
+
+ nft_netdev_event(event, afi, dev, table,
+ nft_base_chain(chain));
+ }
+ }
+ }
+ nfnl_unlock(NFNL_SUBSYS_NFTABLES);
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block nf_tables_netdev_notifier = {
+ .notifier_call = nf_tables_netdev_event,
+};
+
static int __init nf_tables_netdev_init(void)
{
int ret;
@@ -166,11 +238,14 @@ static int __init nf_tables_netdev_init(void)
if (ret < 0)
nft_unregister_chain_type(&nft_filter_chain_netdev);
+ register_netdevice_notifier(&nf_tables_netdev_notifier);
+
return ret;
}
static void __exit nf_tables_netdev_exit(void)
{
+ unregister_netdevice_notifier(&nf_tables_netdev_notifier);
unregister_pernet_subsys(&nf_tables_netdev_net_ops);
nft_unregister_chain_type(&nft_filter_chain_netdev);
}
--
1.7.10.4
--
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