summaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorFlorian Westphal <fw@strlen.de>2016-02-25 10:08:36 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2016-03-02 20:05:24 +0100
commitb9e69e127397187b70c813a4397cce7afb5e8cb1 (patch)
tree1a5a4769ef5ba3087fa15579d15cdd3aa3c3dabd /include
parenta67dd266adf42a24df31380e9da78390bb4d65ef (diff)
netfilter: xtables: don't hook tables by default
delay hook registration until the table is being requested inside a namespace. Historically, a particular table (iptables mangle, ip6tables filter, etc) was registered on module load. When netns support was added to iptables only the ip/ip6tables ruleset was made namespace aware, not the actual hook points. This means f.e. that when ipt_filter table/module is loaded on a system, then each namespace on that system has an (empty) iptables filter ruleset. In other words, if a namespace sends a packet, such skb is 'caught' by netfilter machinery and fed to hooking points for that table (i.e. INPUT, FORWARD, etc). Thanks to Eric Biederman, hooks are no longer global, but per namespace. This means that we can avoid allocation of empty ruleset in a namespace and defer hook registration until we need the functionality. We register a tables hook entry points ONLY in the initial namespace. When an iptables get/setockopt is issued inside a given namespace, we check if the table is found in the per-namespace list. If not, we attempt to find it in the initial namespace, and, if found, create an empty default table in the requesting namespace and register the needed hooks. Hook points are destroyed only once namespace is deleted, there is no 'usage count' (it makes no sense since there is no 'remove table' operation in xtables api). Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/netfilter/x_tables.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index c5577410c25d..80a305b85323 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -200,6 +200,9 @@ struct xt_table {
u_int8_t af; /* address/protocol family */
int priority; /* hook order */
+ /* called when table is needed in the given netns */
+ int (*table_init)(struct net *net);
+
/* A unique name... */
const char name[XT_TABLE_MAXNAMELEN];
};
@@ -408,8 +411,7 @@ xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu)
return cnt;
}
-struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *);
-void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *);
+struct nf_hook_ops *xt_hook_ops_alloc(const struct xt_table *, nf_hookfn *);
#ifdef CONFIG_COMPAT
#include <net/compat.h>