Introduce the xt_helper match revision 1. It uses fixed types,
and its structure size has been adjusted.
The xt_helper revision 0 structure had an odd size of 34 bytes. I
changed this into 32 bytes, which probably plays much better with
cachelines. The invert flag is also shrunk so now there is an
additional byte available for the name as a side effect.
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
---
include/linux/netfilter/xt_helper.h | 6 ++
net/netfilter/xt_helper.c | 84 +++++++++++++++++++++++++++++++++---
2 files changed, 84 insertions(+), 6 deletions(-)
Index: linux-2.6_nosov/include/linux/netfilter/xt_helper.h
===================================================================
--- linux-2.6_nosov.orig/include/linux/netfilter/xt_helper.h
+++ linux-2.6_nosov/include/linux/netfilter/xt_helper.h
@@ -5,4 +5,10 @@ struct xt_helper_info {
int invert;
char name[30];
};
+
+struct xt_helper_match_info {
+ char name[31];
+ u_int8_t invert;
+};
+
#endif /* _XT_HELPER_H */
Index: linux-2.6_nosov/net/netfilter/xt_helper.c
===================================================================
--- linux-2.6_nosov.orig/net/netfilter/xt_helper.c
+++ linux-2.6_nosov/net/netfilter/xt_helper.c
@@ -22,13 +22,46 @@ MODULE_DESCRIPTION("iptables helper matc
MODULE_ALIAS("ipt_helper");
MODULE_ALIAS("ip6t_helper");
-
static bool
helper_mt(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const struct xt_match *match,
const void *matchinfo, int offset, unsigned int protoff,
bool *hotdrop)
{
+ const struct xt_helper_match_info *info = matchinfo;
+ const struct nf_conntrack_helper *helper;
+ const struct nf_conn_help *master_help;
+ enum ip_conntrack_info ctinfo;
+ const struct nf_conn *ct;
+ bool ret = info->invert;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct == NULL || ct->master == NULL)
+ return ret;
+
+ master_help = nfct_help(ct->master);
+ if (master_help == NULL)
+ return ret;
+
+ /* rcu_read_lock()ed by nf_hook_slow */
+ helper = rcu_dereference(master_help->helper);
+ if (helper == NULL)
+ return ret;
+
+ if (info->name[0] == '\0')
+ ret = !ret;
+ else
+ ret ^= strncmp(helper->name, info->name,
+ strlen(helper->name)) == 0;
+ return ret;
+}
+
+static bool
+helper_mt_v0(const struct sk_buff *skb, const struct net_device *in,
+ const struct net_device *out, const struct xt_match *match,
+ const void *matchinfo, int offset, unsigned int protoff,
+ bool *hotdrop)
+{
const struct xt_helper_info *info = matchinfo;
const struct nf_conn *ct;
const struct nf_conn_help *master_help;
@@ -58,9 +91,9 @@ helper_mt(const struct sk_buff *skb, con
}
static bool
-helper_mt_check(const char *tablename, const void *inf,
- const struct xt_match *match, void *matchinfo,
- unsigned int hook_mask)
+helper_mt_check_v0(const char *tablename, const void *inf,
+ const struct xt_match *match, void *matchinfo,
+ unsigned int hook_mask)
{
struct xt_helper_info *info = matchinfo;
@@ -73,6 +106,23 @@ helper_mt_check(const char *tablename, c
return true;
}
+static bool
+helper_mt_check(const char *tablename, const void *ip,
+ const struct xt_match *match, void *matchinfo,
+ unsigned int hook_mask)
+{
+ struct xt_helper_match_info *info = matchinfo;
+
+ if (nf_ct_l3proto_try_module_get(match->family) < 0) {
+ printk(KERN_WARNING "can't load conntrack support for "
+ "proto=%u\n", match->family);
+ return false;
+ }
+
+ info->name[sizeof(info->name)-1] = '\0';
+ return true;
+}
+
static void helper_mt_destroy(const struct xt_match *match, void *matchinfo)
{
nf_ct_l3proto_module_put(match->family);
@@ -81,20 +131,42 @@ static void helper_mt_destroy(const stru
static struct xt_match helper_mt_reg[] __read_mostly = {
{
.name = "helper",
+ .revision = 0,
+ .family = AF_INET,
+ .checkentry = helper_mt_check_v0,
+ .match = helper_mt_v0,
+ .destroy = helper_mt_destroy,
+ .matchsize = sizeof(struct xt_helper_info),
+ .me = THIS_MODULE,
+ },
+ {
+ .name = "helper",
+ .revision = 0,
+ .family = AF_INET6,
+ .checkentry = helper_mt_check_v0,
+ .match = helper_mt_v0,
+ .destroy = helper_mt_destroy,
+ .matchsize = sizeof(struct xt_helper_info),
+ .me = THIS_MODULE,
+ },
+ {
+ .name = "helper",
+ .revision = 1,
.family = AF_INET,
.checkentry = helper_mt_check,
.match = helper_mt,
.destroy = helper_mt_destroy,
- .matchsize = sizeof(struct xt_helper_info),
+ .matchsize = sizeof(struct xt_helper_match_info),
.me = THIS_MODULE,
},
{
.name = "helper",
+ .revision = 1,
.family = AF_INET6,
.checkentry = helper_mt_check,
.match = helper_mt,
.destroy = helper_mt_destroy,
- .matchsize = sizeof(struct xt_helper_info),
+ .matchsize = sizeof(struct xt_helper_match_info),
.me = THIS_MODULE,
},
};
-
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