several problems remain even after this patch:
1. conntrack -E followed by a 'modprobe nf_conntrack_ipv4' will
*not* register ipv4 conntrack hooks (i.e., there will be no output) anymore.
2. since ctnetlink has no dependencies on nf_conntrack_xxx its possible
to rmmod nf_conntrack_xxx while event listener is running which means the
tracker has to remove hooks on netns destruction.
Both issues are addressed in followup patches.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
not part of v2 series.
This is a separate patch to ease review.
include/linux/netfilter/nfnetlink.h | 1 +
net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c | 17 ++++-
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c | 17 ++++-
net/netfilter/nf_conntrack_netlink.c | 86 ++++++++++++++++++++++++++
net/netfilter/nfnetlink.c | 35 ++++++++---
5 files changed, 146 insertions(+), 10 deletions(-)
diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
index 249d1bb..9049c6a 100644
--- a/include/linux/netfilter/nfnetlink.h
+++ b/include/linux/netfilter/nfnetlink.h
@@ -28,6 +28,7 @@ struct nfnetlink_subsystem {
const struct nfnl_callback *cb; /* callback for individual types */
int (*commit)(struct sk_buff *skb);
int (*abort)(struct sk_buff *skb);
+ int (*bind)(struct net *net);
};
int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n);
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index 909681e..7fcccf3 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -401,12 +401,25 @@ static int ipv4_hooks_register(struct net *net)
return err;
}
+static void ipv4_hooks_unregister_force(struct net *net)
+{
+ struct conntrack4_net *cnet = net_generic(net, conntrack4_net_id);
+
+ mutex_lock(®ister_ipv4_hooks);
+ if (cnet->users) {
+ cnet->users = 0;
+ nf_unregister_net_hooks(net, ipv4_conntrack_ops,
+ ARRAY_SIZE(ipv4_conntrack_ops));
+ }
+ mutex_unlock(®ister_ipv4_hooks);
+}
+
static void ipv4_hooks_unregister(struct net *net)
{
struct conntrack4_net *cnet = net_generic(net, conntrack4_net_id);
mutex_lock(®ister_ipv4_hooks);
- if (--cnet->users == 0)
+ if (cnet->users > 0 && --cnet->users == 0)
nf_unregister_net_hooks(net, ipv4_conntrack_ops,
ARRAY_SIZE(ipv4_conntrack_ops));
mutex_unlock(®ister_ipv4_hooks);
@@ -478,6 +491,8 @@ out_tcp:
static void ipv4_net_exit(struct net *net)
{
+ ipv4_hooks_unregister_force(net);
+
nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv4);
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
index 1e6a5f4..f3b422b 100644
--- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
+++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
@@ -340,12 +340,25 @@ static int ipv6_hooks_register(struct net *net)
return err;
}
+static void ipv6_hooks_unregister_force(struct net *net)
+{
+ struct conntrack6_net *cnet = net_generic(net, conntrack6_net_id);
+
+ mutex_lock(®ister_ipv6_hooks);
+ if (cnet->users) {
+ cnet->users = 0;
+ nf_unregister_net_hooks(net, ipv6_conntrack_ops,
+ ARRAY_SIZE(ipv6_conntrack_ops));
+ }
+ mutex_unlock(®ister_ipv6_hooks);
+}
+
static void ipv6_hooks_unregister(struct net *net)
{
struct conntrack6_net *cnet = net_generic(net, conntrack6_net_id);
mutex_lock(®ister_ipv6_hooks);
- if (--cnet->users == 0)
+ if (cnet->users > 0 && --cnet->users == 0)
nf_unregister_net_hooks(net, ipv6_conntrack_ops,
ARRAY_SIZE(ipv6_conntrack_ops));
mutex_unlock(®ister_ipv6_hooks);
@@ -418,6 +431,8 @@ static int ipv6_net_init(struct net *net)
static void ipv6_net_exit(struct net *net)
{
+ ipv6_hooks_unregister_force(net);
+
nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv6);
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmpv6);
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp6);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 9f52729..b8a4067 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -57,6 +57,11 @@
MODULE_LICENSE("GPL");
static char __initdata version[] = "0.93";
+static int ctnetlink_net_id __read_mostly;
+
+struct ctnl_net {
+ DECLARE_BITMAP(enabled, NFPROTO_NUMPROTO);
+};
static inline int
ctnetlink_dump_tuples_proto(struct sk_buff *skb,
@@ -2133,6 +2138,50 @@ ctnetlink_alloc_expect(const struct nlattr *const cda[], struct nf_conn *ct,
struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple *mask);
+static int ctnl_bind(struct net *net)
+{
+ struct ctnl_net *ctnet = net_generic(net, ctnetlink_net_id);
+ int i;
+
+ might_sleep();
+
+ rcu_read_lock();
+
+ for (i = 0; i < NFPROTO_NUMPROTO; i++) {
+ struct nf_conntrack_l3proto *l3proto;
+ int ret;
+
+ /* don't autoload modules; only ensure those present have
+ * their hooks registered.
+ */
+ l3proto = __nf_ct_l3proto_find(i);
+ if (!l3proto || !l3proto->net_ns_get)
+ continue;
+
+ if (test_and_set_bit(i, ctnet->enabled))
+ continue;
+
+ if (!try_module_get(l3proto->me))
+ continue;
+
+ rcu_read_unlock();
+
+ /* might sleep, l3proto can't go away, module ref held */
+ ret = l3proto->net_ns_get(net);
+
+ module_put(l3proto->me);
+
+ if (ret < 0)
+ clear_bit(i, ctnet->enabled);
+
+ rcu_read_lock();
+ }
+
+ rcu_read_unlock();
+
+ return 0;
+}
+
#ifdef CONFIG_NETFILTER_NETLINK_GLUE_CT
static size_t
ctnetlink_glue_build_size(const struct nf_conn *ct)
@@ -3304,6 +3353,7 @@ static const struct nfnetlink_subsystem ctnl_subsys = {
.subsys_id = NFNL_SUBSYS_CTNETLINK,
.cb_count = IPCTNL_MSG_MAX,
.cb = ctnl_cb,
+ .bind = ctnl_bind,
};
static const struct nfnetlink_subsystem ctnl_exp_subsys = {
@@ -3311,6 +3361,7 @@ static const struct nfnetlink_subsystem ctnl_exp_subsys = {
.subsys_id = NFNL_SUBSYS_CTNETLINK_EXP,
.cb_count = IPCTNL_MSG_EXP_MAX,
.cb = ctnl_exp_cb,
+ .bind = ctnl_bind,
};
MODULE_ALIAS("ip_conntrack_netlink");
@@ -3346,10 +3397,43 @@ err_out:
static void ctnetlink_net_exit(struct net *net)
{
+ struct ctnl_net *ctnet = net_generic(net, ctnetlink_net_id);
+ int i;
+
#ifdef CONFIG_NF_CONNTRACK_EVENTS
nf_ct_expect_unregister_notifier(net, &ctnl_notifier_exp);
nf_conntrack_unregister_notifier(net, &ctnl_notifier);
#endif
+
+ might_sleep();
+
+ rcu_read_lock();
+
+ for (i = 0; i < NFPROTO_NUMPROTO; i++) {
+ struct nf_conntrack_l3proto *l3proto;
+
+ if (!test_bit(i, ctnet->enabled))
+ continue;
+
+ l3proto = __nf_ct_l3proto_find(i);
+ /* module might have been unloaded, l3proto->net_ns_put
+ * must have been called by that modules' netns exit handler.
+ */
+ if (!l3proto)
+ continue;
+
+ if (!try_module_get(l3proto->me))
+ continue;
+
+ rcu_read_unlock();
+
+ l3proto->net_ns_put(net);
+ module_put(l3proto->me);
+
+ rcu_read_lock();
+ }
+
+ rcu_read_unlock();
}
static void __net_exit ctnetlink_net_exit_batch(struct list_head *net_exit_list)
@@ -3363,6 +3447,8 @@ static void __net_exit ctnetlink_net_exit_batch(struct list_head *net_exit_list)
static struct pernet_operations ctnetlink_net_ops = {
.init = ctnetlink_net_init,
.exit_batch = ctnetlink_net_exit_batch,
+ .id = &ctnetlink_net_id,
+ .size = sizeof(struct ctnl_net),
};
static int __init ctnetlink_init(void)
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 197b2c6..63a16e6 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -481,11 +481,11 @@ static void nfnetlink_rcv(struct sk_buff *skb)
}
}
-#ifdef CONFIG_MODULES
static int nfnetlink_bind(struct net *net, int group)
{
const struct nfnetlink_subsystem *ss;
- int type;
+ int type, ret;
+ u8 subsys_id;
if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
return 0;
@@ -494,12 +494,33 @@ static int nfnetlink_bind(struct net *net, int group)
rcu_read_lock();
ss = nfnetlink_get_subsys(type << 8);
- rcu_read_unlock();
- if (!ss)
+ ret = -EINVAL;
+#ifdef CONFIG_MODULES
+ if (!ss) {
+ rcu_read_unlock();
request_module("nfnetlink-subsys-%d", type);
- return 0;
-}
+ rcu_read_lock();
+ ss = nfnetlink_get_subsys(type << 8);
+ }
#endif
+ if (!ss) {
+ rcu_read_unlock();
+ return ret;
+ }
+
+ subsys_id = ss->subsys_id;
+ rcu_read_unlock();
+
+ if (!ss->bind)
+ return 0;
+
+ nfnl_lock(subsys_id);
+ if (nfnl_dereference_protected(subsys_id) == ss)
+ ret = ss->bind(net);
+ nfnl_unlock(subsys_id);
+
+ return ret;
+}
static int __net_init nfnetlink_net_init(struct net *net)
{
@@ -507,9 +528,7 @@ static int __net_init nfnetlink_net_init(struct net *net)
struct netlink_kernel_cfg cfg = {
.groups = NFNLGRP_MAX,
.input = nfnetlink_rcv,
-#ifdef CONFIG_MODULES
.bind = nfnetlink_bind,
-#endif
};
nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
--
2.4.10
--
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