@@ -11,6 +11,7 @@
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/static_key.h>
+#include <linux/module.h>
#include <linux/netfilter_defs.h>
#include <linux/netdevice.h>
#include <linux/sockptr.h>
@@ -481,6 +482,15 @@ struct nfnl_ct_hook {
};
extern const struct nfnl_ct_hook __rcu *nfnl_ct_hook;
+struct nf_defrag_hook {
+ struct module *owner;
+ int (*enable)(struct net *net);
+ void (*disable)(struct net *net);
+};
+
+extern const struct nf_defrag_hook __rcu *nf_defrag_v4_hook;
+extern const struct nf_defrag_hook __rcu *nf_defrag_v6_hook;
+
/*
* nf_skb_duplicated - TEE target has sent a packet
*
@@ -7,6 +7,7 @@
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <linux/module.h>
+#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <net/netns/generic.h>
#include <net/route.h>
@@ -113,17 +114,31 @@ static void __net_exit defrag4_net_exit(struct net *net)
}
}
+static const struct nf_defrag_hook defrag_hook = {
+ .owner = THIS_MODULE,
+ .enable = nf_defrag_ipv4_enable,
+ .disable = nf_defrag_ipv4_disable,
+};
+
static struct pernet_operations defrag4_net_ops = {
.exit = defrag4_net_exit,
};
static int __init nf_defrag_init(void)
{
- return register_pernet_subsys(&defrag4_net_ops);
+ int err;
+
+ err = register_pernet_subsys(&defrag4_net_ops);
+ if (err)
+ return err;
+
+ rcu_assign_pointer(nf_defrag_v4_hook, &defrag_hook);
+ return err;
}
static void __exit nf_defrag_fini(void)
{
+ rcu_assign_pointer(nf_defrag_v4_hook, NULL);
unregister_pernet_subsys(&defrag4_net_ops);
}
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
+#include <linux/rcupdate.h>
#include <linux/sysctl.h>
#include <net/ipv6_frag.h>
@@ -96,6 +97,12 @@ static void __net_exit defrag6_net_exit(struct net *net)
}
}
+static const struct nf_defrag_hook defrag_hook = {
+ .owner = THIS_MODULE,
+ .enable = nf_defrag_ipv6_enable,
+ .disable = nf_defrag_ipv6_disable,
+};
+
static struct pernet_operations defrag6_net_ops = {
.exit = defrag6_net_exit,
};
@@ -114,6 +121,9 @@ static int __init nf_defrag_init(void)
pr_err("nf_defrag_ipv6: can't register pernet ops\n");
goto cleanup_frag6;
}
+
+ rcu_assign_pointer(nf_defrag_v6_hook, &defrag_hook);
+
return ret;
cleanup_frag6:
@@ -124,6 +134,7 @@ static int __init nf_defrag_init(void)
static void __exit nf_defrag_fini(void)
{
+ rcu_assign_pointer(nf_defrag_v6_hook, NULL);
unregister_pernet_subsys(&defrag6_net_ops);
nf_ct_frag6_cleanup();
}
@@ -680,6 +680,12 @@ EXPORT_SYMBOL_GPL(nfnl_ct_hook);
const struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
EXPORT_SYMBOL_GPL(nf_ct_hook);
+const struct nf_defrag_hook __rcu *nf_defrag_v4_hook __read_mostly;
+EXPORT_SYMBOL_GPL(nf_defrag_v4_hook);
+
+const struct nf_defrag_hook __rcu *nf_defrag_v6_hook __read_mostly;
+EXPORT_SYMBOL_GPL(nf_defrag_v6_hook);
+
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
u8 nf_ctnetlink_has_listener;
EXPORT_SYMBOL_GPL(nf_ctnetlink_has_listener);
We want to be able to enable/disable IP packet defrag from core bpf/netfilter code. In other words, execute code from core that could possibly be built as a module. To help avoid symbol resolution errors, use glue hooks that the modules will register callbacks with during module init. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> --- include/linux/netfilter.h | 10 ++++++++++ net/ipv4/netfilter/nf_defrag_ipv4.c | 17 ++++++++++++++++- net/ipv6/netfilter/nf_defrag_ipv6_hooks.c | 11 +++++++++++ net/netfilter/core.c | 6 ++++++ 4 files changed, 43 insertions(+), 1 deletion(-)