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From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Mon, 27 Nov 2017 22:50:26 +0100
Subject: [PATCH] netfilter: move reroute indirection to struct nf_ipv6_ops
We cannot make a direct call to nf_ip6_reroute() because that would result
in autoloading the 'ipv6' module because of symbol dependencies.
Therefore, define reroute indirection in nf_ipv6_ops where this really
belongs to.
For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -311,8 +311,6 @@ struct nf_queue_entry;
struct nf_afinfo {
unsigned short family;
- int (*reroute)(struct net *net, struct sk_buff *skb,
- const struct nf_queue_entry *entry);
int route_key_size;
};
@@ -331,6 +329,7 @@ __sum16 nf_checksum_partial(struct sk_bu
u_int8_t protocol, unsigned short family);
int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
bool strict, unsigned short family);
+int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry);
int nf_register_afinfo(const struct nf_afinfo *afinfo);
void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
--- a/include/linux/netfilter_ipv4.h
+++ b/include/linux/netfilter_ipv4.h
@@ -18,6 +18,8 @@ struct ip_rt_info {
int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned addr_type);
+struct nf_queue_entry;
+
#ifdef CONFIG_INET
__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol);
@@ -26,6 +28,7 @@ __sum16 nf_ip_checksum_partial(struct sk
u_int8_t protocol);
int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
bool strict);
+int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry);
#else
static inline __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol)
@@ -45,6 +48,11 @@ static inline int nf_ip_route(struct net
{
return -EOPNOTSUPP;
}
+static inline int nf_ip_reroute(struct sk_buff *skb,
+ const struct nf_queue_entry *entry)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_INET */
#endif /*__LINUX_IP_NETFILTER_H*/
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -18,6 +18,8 @@ struct ip6_rt_info {
u_int32_t mark;
};
+struct nf_queue_entry;
+
/*
* Hook functions for ipv6 to allow xt_* modules to be built-in even
* if IPv6 is a module.
@@ -35,6 +37,7 @@ struct nf_ipv6_ops {
u_int8_t protocol);
int (*route)(struct net *net, struct dst_entry **dst, struct flowi *fl,
bool strict);
+ int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry);
};
#ifdef CONFIG_NETFILTER
--- a/net/bridge/netfilter/nf_tables_bridge.c
+++ b/net/bridge/netfilter/nf_tables_bridge.c
@@ -95,15 +95,8 @@ static const struct nf_chain_type filter
(1 << NF_BR_POST_ROUTING),
};
-static int nf_br_reroute(struct net *net, struct sk_buff *skb,
- const struct nf_queue_entry *entry)
-{
- return 0;
-}
-
static const struct nf_afinfo nf_br_afinfo = {
.family = AF_BRIDGE,
- .reroute = nf_br_reroute,
.route_key_size = 0,
};
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -80,8 +80,7 @@ int ip_route_me_harder(struct net *net,
}
EXPORT_SYMBOL(ip_route_me_harder);
-static int nf_ip_reroute(struct net *net, struct sk_buff *skb,
- const struct nf_queue_entry *entry)
+int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry)
{
const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
@@ -92,10 +91,12 @@ static int nf_ip_reroute(struct net *net
skb->mark == rt_info->mark &&
iph->daddr == rt_info->daddr &&
iph->saddr == rt_info->saddr))
- return ip_route_me_harder(net, skb, RTN_UNSPEC);
+ return ip_route_me_harder(entry->state.net, skb,
+ RTN_UNSPEC);
}
return 0;
}
+EXPORT_SYMBOL_GPL(nf_ip_reroute);
__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol)
@@ -163,7 +164,6 @@ EXPORT_SYMBOL_GPL(nf_ip_route);
static const struct nf_afinfo nf_ip_afinfo = {
.family = AF_INET,
- .reroute = nf_ip_reroute,
.route_key_size = sizeof(struct ip_rt_info),
};
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -72,7 +72,7 @@ int ip6_route_me_harder(struct net *net,
}
EXPORT_SYMBOL(ip6_route_me_harder);
-static int nf_ip6_reroute(struct net *net, struct sk_buff *skb,
+static int nf_ip6_reroute(struct sk_buff *skb,
const struct nf_queue_entry *entry)
{
struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
@@ -82,7 +82,7 @@ static int nf_ip6_reroute(struct net *ne
if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
!ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
skb->mark != rt_info->mark)
- return ip6_route_me_harder(net, skb);
+ return ip6_route_me_harder(entry->state.net, skb);
}
return 0;
}
@@ -175,11 +175,11 @@ static const struct nf_ipv6_ops ipv6ops
.checksum = nf_ip6_checksum,
.checksum_partial = nf_ip6_checksum_partial,
.route = nf_ip6_route,
+ .reroute = nf_ip6_reroute,
};
static const struct nf_afinfo nf_ip6_afinfo = {
.family = AF_INET6,
- .reroute = nf_ip6_reroute,
.route_key_size = sizeof(struct ip6_rt_info),
};
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -271,7 +271,6 @@ void nf_reinject(struct nf_queue_entry *
const struct nf_hook_entry *hook_entry;
const struct nf_hook_entries *hooks;
struct sk_buff *skb = entry->skb;
- const struct nf_afinfo *afinfo;
const struct net *net;
unsigned int i;
int err;
@@ -298,8 +297,7 @@ void nf_reinject(struct nf_queue_entry *
verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
if (verdict == NF_ACCEPT) {
- afinfo = nf_get_afinfo(entry->state.pf);
- if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0)
+ if (nf_reroute(skb, entry) < 0)
verdict = NF_DROP;
}
--- a/net/netfilter/utils.c
+++ b/net/netfilter/utils.c
@@ -2,6 +2,7 @@
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
+#include <net/netfilter/nf_queue.h>
__sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol,
@@ -69,3 +70,21 @@ int nf_route(struct net *net, struct dst
return ret;
}
EXPORT_SYMBOL_GPL(nf_route);
+
+int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry)
+{
+ const struct nf_ipv6_ops *v6ops;
+ int ret = 0;
+
+ switch (entry->state.pf) {
+ case AF_INET:
+ ret = nf_ip_reroute(skb, entry);
+ break;
+ case AF_INET6:
+ v6ops = rcu_dereference(nf_ipv6_ops);
+ if (v6ops)
+ ret = v6ops->reroute(skb, entry);
+ break;
+ }
+ return ret;
+}
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