netfilter: don't allocate space for arp/bridge hooks unless needed

no need to define hook points if the family isn't supported.
Because we need these hooks for either nftables, arp/ebtables
or the 'call-iptables' hack we have in the bridge layer add two
new dependencies, NETFILTER_FAMILY_{ARP,BRIDGE}, and have the
users select them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2017-12-07 16:28:26 +01:00 committed by Pablo Neira Ayuso
parent bb4badf3a3
commit 2a95183a5e
8 changed files with 29 additions and 0 deletions

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@ -214,10 +214,14 @@ static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
break;
case NFPROTO_ARP:
#ifdef CONFIG_NETFILTER_FAMILY_ARP
hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
#endif
break;
case NFPROTO_BRIDGE:
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
hook_head = rcu_dereference(net->nf.hooks_bridge[hook]);
#endif
break;
#if IS_ENABLED(CONFIG_DECNET)
case NFPROTO_DECNET:

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@ -19,8 +19,12 @@ struct netns_nf {
#endif
struct nf_hook_entries __rcu *hooks_ipv4[NF_INET_NUMHOOKS];
struct nf_hook_entries __rcu *hooks_ipv6[NF_INET_NUMHOOKS];
#ifdef CONFIG_NETFILTER_FAMILY_ARP
struct nf_hook_entries __rcu *hooks_arp[NF_ARP_NUMHOOKS];
#endif
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
struct nf_hook_entries __rcu *hooks_bridge[NF_INET_NUMHOOKS];
#endif
#if IS_ENABLED(CONFIG_DECNET)
struct nf_hook_entries __rcu *hooks_decnet[NF_DN_NUMHOOKS];
#endif

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@ -182,6 +182,7 @@ config BRIDGE_NETFILTER
depends on BRIDGE
depends on NETFILTER && INET
depends on NETFILTER_ADVANCED
select NETFILTER_FAMILY_BRIDGE
default m
---help---
Enabling this option will let arptables resp. iptables see bridged

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@ -4,6 +4,7 @@
#
menuconfig NF_TABLES_BRIDGE
depends on BRIDGE && NETFILTER && NF_TABLES
select NETFILTER_FAMILY_BRIDGE
tristate "Ethernet Bridge nf_tables support"
if NF_TABLES_BRIDGE
@ -29,6 +30,7 @@ endif # NF_TABLES_BRIDGE
menuconfig BRIDGE_NF_EBTABLES
tristate "Ethernet Bridge tables (ebtables) support"
depends on BRIDGE && NETFILTER && NETFILTER_XTABLES
select NETFILTER_FAMILY_BRIDGE
help
ebtables is a general, extensible frame/packet identification
framework. Say 'Y' or 'M' here if you want to do Ethernet

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@ -72,6 +72,7 @@ endif # NF_TABLES_IPV4
config NF_TABLES_ARP
tristate "ARP nf_tables support"
select NETFILTER_FAMILY_ARP
help
This option enables the ARP support for nf_tables.
@ -392,6 +393,7 @@ endif # IP_NF_IPTABLES
config IP_NF_ARPTABLES
tristate "ARP tables support"
select NETFILTER_XTABLES
select NETFILTER_FAMILY_ARP
depends on NETFILTER_ADVANCED
help
arptables is a general, extensible packet identification framework.

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@ -12,6 +12,12 @@ config NETFILTER_INGRESS
config NETFILTER_NETLINK
tristate
config NETFILTER_FAMILY_BRIDGE
bool
config NETFILTER_FAMILY_ARP
bool
config NETFILTER_NETLINK_ACCT
tristate "Netfilter NFACCT over NFNETLINK interface"
depends on NETFILTER_ADVANCED

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@ -267,14 +267,18 @@ static struct nf_hook_entries __rcu **nf_hook_entry_head(struct net *net, const
switch (reg->pf) {
case NFPROTO_NETDEV:
break;
#ifdef CONFIG_NETFILTER_FAMILY_ARP
case NFPROTO_ARP:
if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_arp) <= reg->hooknum))
return NULL;
return net->nf.hooks_arp + reg->hooknum;
#endif
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
case NFPROTO_BRIDGE:
if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_bridge) <= reg->hooknum))
return NULL;
return net->nf.hooks_bridge + reg->hooknum;
#endif
case NFPROTO_IPV4:
if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv4) <= reg->hooknum))
return NULL;
@ -573,8 +577,12 @@ static int __net_init netfilter_net_init(struct net *net)
{
__netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
__netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
#ifdef CONFIG_NETFILTER_FAMILY_ARP
__netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
#endif
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
__netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
#endif
#if IS_ENABLED(CONFIG_DECNET)
__netfilter_net_init(net->nf.hooks_decnet, ARRAY_SIZE(net->nf.hooks_decnet));
#endif

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@ -204,8 +204,10 @@ static unsigned int nf_iterate(struct sk_buff *skb,
static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
{
switch (pf) {
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
case NFPROTO_BRIDGE:
return rcu_dereference(net->nf.hooks_bridge[hooknum]);
#endif
case NFPROTO_IPV4:
return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
case NFPROTO_IPV6: