From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
This patch allows you to set expectfn which is specifically used
by the NAT side of most of the existing conntrack helpers.
I have added a symbol map that uses a string as key to look up for
the function that is attached to the expectation object. This is
the best solution I came out with to solve this issue.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/linux/netfilter/nfnetlink_conntrack.h | 1 +
include/net/netfilter/nf_conntrack_helper.h | 13 ++++++
net/ipv4/netfilter/nf_nat_core.c | 8 ++++
net/ipv4/netfilter/nf_nat_h323.c | 14 ++++++
net/ipv4/netfilter/nf_nat_sip.c | 7 +++
net/netfilter/nf_conntrack_helper.c | 54 +++++++++++++++++++++++++
net/netfilter/nf_conntrack_netlink.c | 19 ++++++++-
7 files changed, 115 insertions(+), 1 deletions(-)
diff --git a/include/linux/netfilter/nfnetlink_conntrack.h b/include/linux/netfilter/nfnetlink_conntrack.h
index a2f1f48..e58e4b9 100644
--- a/include/linux/netfilter/nfnetlink_conntrack.h
+++ b/include/linux/netfilter/nfnetlink_conntrack.h
@@ -175,6 +175,7 @@ enum ctattr_expect {
CTA_EXPECT_FLAGS,
CTA_EXPECT_CLASS,
CTA_EXPECT_NAT,
+ CTA_EXPECT_FN,
__CTA_EXPECT_MAX
};
#define CTA_EXPECT_MAX (__CTA_EXPECT_MAX - 1)
diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index f1c1311..5767dc2 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -69,4 +69,17 @@ extern int nf_conntrack_broadcast_help(struct sk_buff *skb,
enum ip_conntrack_info ctinfo,
unsigned int timeout);
+struct nf_ct_helper_expectfn {
+ struct list_head head;
+ const char *name;
+ void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
+};
+
+void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
+void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
+struct nf_ct_helper_expectfn *
+nf_ct_helper_expectfn_find_by_name(const char *name);
+struct nf_ct_helper_expectfn *
+nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
+
#endif /*_NF_CONNTRACK_HELPER_H*/
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index a708933..abb52ad 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -686,6 +686,11 @@ static struct pernet_operations nf_nat_net_ops = {
.exit = nf_nat_net_exit,
};
+static struct nf_ct_helper_expectfn follow_master_nat = {
+ .name = "nat-follow-master",
+ .expectfn = nf_nat_follow_master,
+};
+
static int __init nf_nat_init(void)
{
size_t i;
@@ -717,6 +722,8 @@ static int __init nf_nat_init(void)
l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
+ nf_ct_helper_expectfn_register(&follow_master_nat);
+
BUG_ON(nf_nat_seq_adjust_hook != NULL);
RCU_INIT_POINTER(nf_nat_seq_adjust_hook, nf_nat_seq_adjust);
BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
@@ -736,6 +743,7 @@ static void __exit nf_nat_cleanup(void)
unregister_pernet_subsys(&nf_nat_net_ops);
nf_ct_l3proto_put(l3proto);
nf_ct_extend_unregister(&nat_extend);
+ nf_ct_helper_expectfn_unregister(&follow_master_nat);
RCU_INIT_POINTER(nf_nat_seq_adjust_hook, NULL);
RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL);
RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
diff --git a/net/ipv4/netfilter/nf_nat_h323.c b/net/ipv4/netfilter/nf_nat_h323.c
index dc1dd91..8253670 100644
--- a/net/ipv4/netfilter/nf_nat_h323.c
+++ b/net/ipv4/netfilter/nf_nat_h323.c
@@ -568,6 +568,16 @@ static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct,
return 0;
}
+static struct nf_ct_helper_expectfn q931_nat = {
+ .name = "Q.931",
+ .expectfn = ip_nat_q931_expect,
+};
+
+static struct nf_ct_helper_expectfn callforwarding_nat = {
+ .name = "callforwarding",
+ .expectfn = ip_nat_callforwarding_expect,
+};
+
/****************************************************************************/
static int __init init(void)
{
@@ -590,6 +600,8 @@ static int __init init(void)
RCU_INIT_POINTER(nat_h245_hook, nat_h245);
RCU_INIT_POINTER(nat_callforwarding_hook, nat_callforwarding);
RCU_INIT_POINTER(nat_q931_hook, nat_q931);
+ nf_ct_helper_expectfn_register(&q931_nat);
+ nf_ct_helper_expectfn_register(&callforwarding_nat);
return 0;
}
@@ -605,6 +617,8 @@ static void __exit fini(void)
RCU_INIT_POINTER(nat_h245_hook, NULL);
RCU_INIT_POINTER(nat_callforwarding_hook, NULL);
RCU_INIT_POINTER(nat_q931_hook, NULL);
+ nf_ct_helper_expectfn_unregister(&q931_nat);
+ nf_ct_helper_expectfn_unregister(&callforwarding_nat);
synchronize_rcu();
}
diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c
index d0319f9..57932c4 100644
--- a/net/ipv4/netfilter/nf_nat_sip.c
+++ b/net/ipv4/netfilter/nf_nat_sip.c
@@ -526,6 +526,11 @@ err1:
return NF_DROP;
}
+static struct nf_ct_helper_expectfn sip_nat = {
+ .name = "sip",
+ .expectfn = ip_nat_sip_expected,
+};
+
static void __exit nf_nat_sip_fini(void)
{
RCU_INIT_POINTER(nf_nat_sip_hook, NULL);
@@ -535,6 +540,7 @@ static void __exit nf_nat_sip_fini(void)
RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL);
RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL);
RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL);
+ nf_ct_helper_expectfn_unregister(&sip_nat);
synchronize_rcu();
}
@@ -554,6 +560,7 @@ static int __init nf_nat_sip_init(void)
RCU_INIT_POINTER(nf_nat_sdp_port_hook, ip_nat_sdp_port);
RCU_INIT_POINTER(nf_nat_sdp_session_hook, ip_nat_sdp_session);
RCU_INIT_POINTER(nf_nat_sdp_media_hook, ip_nat_sdp_media);
+ nf_ct_helper_expectfn_register(&sip_nat);
return 0;
}
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index bbe23ba..436b7cb 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -181,6 +181,60 @@ void nf_ct_helper_destroy(struct nf_conn *ct)
}
}
+static LIST_HEAD(nf_ct_helper_expectfn_list);
+
+void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n)
+{
+ spin_lock_bh(&nf_conntrack_lock);
+ list_add_rcu(&n->head, &nf_ct_helper_expectfn_list);
+ spin_unlock_bh(&nf_conntrack_lock);
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_register);
+
+void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n)
+{
+ spin_lock_bh(&nf_conntrack_lock);
+ list_del_rcu(&n->head);
+ spin_unlock_bh(&nf_conntrack_lock);
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister);
+
+struct nf_ct_helper_expectfn *
+nf_ct_helper_expectfn_find_by_name(const char *name)
+{
+ struct nf_ct_helper_expectfn *cur;
+ bool found = false;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
+ if (!strcmp(cur->name, name)) {
+ found = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ return found ? cur : NULL;
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name);
+
+struct nf_ct_helper_expectfn *
+nf_ct_helper_expectfn_find_by_symbol(const void *symbol)
+{
+ struct nf_ct_helper_expectfn *cur;
+ bool found = false;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
+ if (cur->expectfn == symbol) {
+ found = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ return found ? cur : NULL;
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol);
+
int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
{
unsigned int h = helper_hash(&me->tuple);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 845c8ca..b8827e8 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1679,6 +1679,8 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb,
struct nlattr *nest_parms;
struct nf_conntrack_tuple nat_tuple = {};
#endif
+ struct nf_ct_helper_expectfn *expfn;
+
if (timeout < 0)
timeout = 0;
@@ -1722,6 +1724,9 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb,
if (helper)
NLA_PUT_STRING(skb, CTA_EXPECT_HELP_NAME, helper->name);
}
+ expfn = nf_ct_helper_expectfn_find_by_symbol(exp->expectfn);
+ if (expfn != NULL)
+ NLA_PUT_STRING(skb, CTA_EXPECT_FN, expfn->name);
return 0;
@@ -1881,6 +1886,7 @@ static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = {
[CTA_EXPECT_FLAGS] = { .type = NLA_U32 },
[CTA_EXPECT_CLASS] = { .type = NLA_U32 },
[CTA_EXPECT_NAT] = { .type = NLA_NESTED },
+ [CTA_EXPECT_FN] = { .type = NLA_NUL_STRING },
};
static int
@@ -2182,9 +2188,20 @@ ctnetlink_create_expect(struct net *net, u16 zone,
} else
exp->flags = 0;
}
+ if (cda[CTA_EXPECT_FN]) {
+ const char *name = nla_data(cda[CTA_EXPECT_FN]);
+ struct nf_ct_helper_expectfn *expfn;
+
+ expfn = nf_ct_helper_expectfn_find_by_name(name);
+ if (expfn == NULL) {
+ err = -EINVAL;
+ goto err_out;
+ }
+ exp->expectfn = expfn->expectfn;
+ } else
+ exp->expectfn = NULL;
exp->class = class;
- exp->expectfn = NULL;
exp->master = ct;
exp->helper = helper;
memcpy(&exp->tuple, &tuple, sizeof(struct nf_conntrack_tuple));
--
1.7.7.3
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