diff options
author | Florian Westphal <fw@strlen.de> | 2016-11-15 21:36:45 +0100 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-12-06 21:42:00 +0100 |
commit | 834184b1f3a4635efbdfdae5fb437f109f6605fa (patch) | |
tree | 6ea25a837123c698a7feead4ee5e2d0f2e74cda4 /net/ipv6 | |
parent | 481fa3734769b67f00ed09a42f2a6a8cbd00b869 (diff) |
netfilter: defrag: only register defrag functionality if needed
nf_defrag modules for ipv4 and ipv6 export an empty stub function.
Any module that needs the defragmentation hooks registered simply 'calls'
this empty function to create a phony module dependency -- modprobe will
then load the defrag module too.
This extends netfilter ipv4/ipv6 defragmentation modules to delay the hook
registration until the functionality is requested within a network namespace
instead of module load time for all namespaces.
Hooks are only un-registered on module unload or when a namespace that used
such defrag functionality exits.
We have to use struct net for this as the register hooks can be called
before netns initialization here from the ipv4/ipv6 conntrack module
init path.
There is no unregister functionality support, defrag will always be
active once it was requested inside a net namespace.
The reason is that defrag has impact on nft and iptables rulesets
(without defrag we might see framents).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r-- | net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c | 7 | ||||
-rw-r--r-- | net/ipv6/netfilter/nf_defrag_ipv6_hooks.c | 42 |
2 files changed, 44 insertions, 5 deletions
diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c index 72fe48075b7f..4e3402486833 100644 --- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c +++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c @@ -325,6 +325,12 @@ static int ipv6_hooks_register(struct net *net) if (cnet->users > 1) goto out_unlock; + err = nf_defrag_ipv6_enable(net); + if (err < 0) { + cnet->users = 0; + goto out_unlock; + } + err = nf_register_net_hooks(net, ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops)); if (err) @@ -427,7 +433,6 @@ static int __init nf_conntrack_l3proto_ipv6_init(void) int ret = 0; need_conntrack(); - nf_defrag_ipv6_enable(); ret = nf_register_sockopt(&so_getorigdst6); if (ret < 0) { diff --git a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c index f06b0471f39f..8e0bdd058787 100644 --- a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c +++ b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c @@ -30,6 +30,8 @@ #include <net/netfilter/nf_conntrack_zones.h> #include <net/netfilter/ipv6/nf_defrag_ipv6.h> +static DEFINE_MUTEX(defrag6_mutex); + static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum, struct sk_buff *skb) { @@ -87,6 +89,19 @@ static struct nf_hook_ops ipv6_defrag_ops[] = { }, }; +static void __net_exit defrag6_net_exit(struct net *net) +{ + if (net->nf.defrag_ipv6) { + nf_unregister_net_hooks(net, ipv6_defrag_ops, + ARRAY_SIZE(ipv6_defrag_ops)); + net->nf.defrag_ipv6 = false; + } +} + +static struct pernet_operations defrag6_net_ops = { + .exit = defrag6_net_exit, +}; + static int __init nf_defrag_init(void) { int ret = 0; @@ -96,9 +111,9 @@ static int __init nf_defrag_init(void) pr_err("nf_defrag_ipv6: can't initialize frag6.\n"); return ret; } - ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops)); + ret = register_pernet_subsys(&defrag6_net_ops); if (ret < 0) { - pr_err("nf_defrag_ipv6: can't register hooks\n"); + pr_err("nf_defrag_ipv6: can't register pernet ops\n"); goto cleanup_frag6; } return ret; @@ -111,12 +126,31 @@ cleanup_frag6: static void __exit nf_defrag_fini(void) { - nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops)); + unregister_pernet_subsys(&defrag6_net_ops); nf_ct_frag6_cleanup(); } -void nf_defrag_ipv6_enable(void) +int nf_defrag_ipv6_enable(struct net *net) { + int err = 0; + + might_sleep(); + + if (net->nf.defrag_ipv6) + return 0; + + mutex_lock(&defrag6_mutex); + if (net->nf.defrag_ipv6) + goto out_unlock; + + err = nf_register_net_hooks(net, ipv6_defrag_ops, + ARRAY_SIZE(ipv6_defrag_ops)); + if (err == 0) + net->nf.defrag_ipv6 = true; + + out_unlock: + mutex_unlock(&defrag6_mutex); + return err; } EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable); |