netfilter: kill support for per-af queue backends

We used to have several queueing backends, but nowadays only
nfnetlink_queue remains.

In light of this there doesn't seem to be a good reason to
support per-af registering -- just hook up nfnetlink_queue on module
load and remove it on unload.

This means that the userspace BIND/UNBIND_PF commands are now obsolete;
the kernel will ignore them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 18 insertions, 150 deletions

diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 68912dadf13d..a9c488b6c50d 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -295,8 +295,6 @@ void __init netfilter_init(void)
                 panic("cannot create netfilter proc entry");
 #endif
 
-        if (netfilter_queue_init() < 0)
-                panic("cannot initialize nf_queue");
         if (netfilter_log_init() < 0)
                 panic("cannot initialize nf_log");
 }
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 8d2cf9ec37a8..d812c1235b30 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -14,84 +14,32 @@
 #include "nf_internals.h"
 
 /*
- * A queue handler may be registered for each protocol.  Each is protected by
- * long term mutex.  The handler must provide an an outfn() to accept packets
- * for queueing and must reinject all packets it receives, no matter what.
+ * Hook for nfnetlink_queue to register its queue handler.
+ * We do this so that most of the NFQUEUE code can be modular.
+ *
+ * Once the queue is registered it must reinject all packets it
+ * receives, no matter what.
  */
-static const struct nf_queue_handler __rcu *queue_handler[NFPROTO_NUMPROTO] __read_mostly;
-
-static DEFINE_MUTEX(queue_handler_mutex);
+static const struct nf_queue_handler __rcu *queue_handler __read_mostly;
 
 /* return EBUSY when somebody else is registered, return EEXIST if the
  * same handler is registered, return 0 in case of success. */
-int nf_register_queue_handler(u_int8_t pf, const struct nf_queue_handler *qh)
+void nf_register_queue_handler(const struct nf_queue_handler *qh)
 {
-        int ret;
-        const struct nf_queue_handler *old;
-
-        if (pf >= ARRAY_SIZE(queue_handler))
-                return -EINVAL;
-
-        mutex_lock(&queue_handler_mutex);
-        old = rcu_dereference_protected(queue_handler[pf],
-                                        lockdep_is_held(&queue_handler_mutex));
-        if (old == qh)
-                ret = -EEXIST;
-        else if (old)
-                ret = -EBUSY;
-        else {
-                rcu_assign_pointer(queue_handler[pf], qh);
-                ret = 0;
-        }
-        mutex_unlock(&queue_handler_mutex);
-
-        return ret;
+        /* should never happen, we only have one queueing backend in kernel */
+        WARN_ON(rcu_access_pointer(queue_handler));
+        rcu_assign_pointer(queue_handler, qh);
 }
 EXPORT_SYMBOL(nf_register_queue_handler);
 
 /* The caller must flush their queue before this */
-int nf_unregister_queue_handler(u_int8_t pf, const struct nf_queue_handler *qh)
+void nf_unregister_queue_handler(void)
 {
-        const struct nf_queue_handler *old;
-
-        if (pf >= ARRAY_SIZE(queue_handler))
-                return -EINVAL;
-
-        mutex_lock(&queue_handler_mutex);
-        old = rcu_dereference_protected(queue_handler[pf],
-                                        lockdep_is_held(&queue_handler_mutex));
-        if (old && old != qh) {
-                mutex_unlock(&queue_handler_mutex);
-                return -EINVAL;
-        }
-
-        RCU_INIT_POINTER(queue_handler[pf], NULL);
-        mutex_unlock(&queue_handler_mutex);
-
+        RCU_INIT_POINTER(queue_handler, NULL);
         synchronize_rcu();
-
-        return 0;
 }
 EXPORT_SYMBOL(nf_unregister_queue_handler);
 
-void nf_unregister_queue_handlers(const struct nf_queue_handler *qh)
-{
-        u_int8_t pf;
-
-        mutex_lock(&queue_handler_mutex);
-        for (pf = 0; pf < ARRAY_SIZE(queue_handler); pf++)  {
-                if (rcu_dereference_protected(
-                                queue_handler[pf],
-                                lockdep_is_held(&queue_handler_mutex)
-                                ) == qh)
-                        RCU_INIT_POINTER(queue_handler[pf], NULL);
-        }
-        mutex_unlock(&queue_handler_mutex);
-
-        synchronize_rcu();
-}
-EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
-
 static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
 {
         /* Release those devices we held, or Alexey will kill me. */
@@ -137,7 +85,7 @@ static int __nf_queue(struct sk_buff *skb,
         /* QUEUE == DROP if no one is waiting, to be safe. */
         rcu_read_lock();
 
-        qh = rcu_dereference(queue_handler[pf]);
+        qh = rcu_dereference(queue_handler);
         if (!qh) {
                 status = -ESRCH;
                 goto err_unlock;
@@ -344,77 +292,3 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
         kfree(entry);
 }
 EXPORT_SYMBOL(nf_reinject);
-
-#ifdef CONFIG_PROC_FS
-static void *seq_start(struct seq_file *seq, loff_t *pos)
-{
-        if (*pos >= ARRAY_SIZE(queue_handler))
-                return NULL;
-
-        return pos;
-}
-
-static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
-{
-        (*pos)++;
-
-        if (*pos >= ARRAY_SIZE(queue_handler))
-                return NULL;
-
-        return pos;
-}
-
-static void seq_stop(struct seq_file *s, void *v)
-{
-
-}
-
-static int seq_show(struct seq_file *s, void *v)
-{
-        int ret;
-        loff_t *pos = v;
-        const struct nf_queue_handler *qh;
-
-        rcu_read_lock();
-        qh = rcu_dereference(queue_handler[*pos]);
-        if (!qh)
-                ret = seq_printf(s, "%2lld NONE\n", *pos);
-        else
-                ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);
-        rcu_read_unlock();
-
-        return ret;
-}
-
-static const struct seq_operations nfqueue_seq_ops = {
-        .start  = seq_start,
-        .next   = seq_next,
-        .stop   = seq_stop,
-        .show   = seq_show,
-};
-
-static int nfqueue_open(struct inode *inode, struct file *file)
-{
-        return seq_open(file, &nfqueue_seq_ops);
-}
-
-static const struct file_operations nfqueue_file_ops = {
-        .owner   = THIS_MODULE,
-        .open    = nfqueue_open,
-        .read    = seq_read,
-        .llseek  = seq_lseek,
-        .release = seq_release,
-};
-#endif /* PROC_FS */
-
-
-int __init netfilter_queue_init(void)
-{
-#ifdef CONFIG_PROC_FS
-        if (!proc_create("nf_queue", S_IRUGO,
-                         proc_net_netfilter, &nfqueue_file_ops))
-                return -1;
-#endif
-        return 0;
-}
-
diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c
index e12d44e75b21..3158d87b56a8 100644
--- a/net/netfilter/nfnetlink_queue_core.c
+++ b/net/netfilter/nfnetlink_queue_core.c
@@ -809,7 +809,6 @@ static const struct nla_policy nfqa_cfg_policy[NFQA_CFG_MAX+1] = {
 };
 
 static const struct nf_queue_handler nfqh = {
-        .name   = "nf_queue",
         .outfn  = &nfqnl_enqueue_packet,
 };
 
@@ -827,14 +826,10 @@ nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
         if (nfqa[NFQA_CFG_CMD]) {
                 cmd = nla_data(nfqa[NFQA_CFG_CMD]);
 
-                /* Commands without queue context - might sleep */
+                /* Obsolete commands without queue context */
                 switch (cmd->command) {
-                case NFQNL_CFG_CMD_PF_BIND:
-                        return nf_register_queue_handler(ntohs(cmd->pf),
-                                                         &nfqh);
-                case NFQNL_CFG_CMD_PF_UNBIND:
-                        return nf_unregister_queue_handler(ntohs(cmd->pf),
-                                                           &nfqh);
+                case NFQNL_CFG_CMD_PF_BIND: return 0;
+                case NFQNL_CFG_CMD_PF_UNBIND: return 0;
                 }
         }
 
@@ -1074,6 +1069,7 @@ static int __init nfnetlink_queue_init(void)
 #endif
 
         register_netdevice_notifier(&nfqnl_dev_notifier);
+        nf_register_queue_handler(&nfqh);
         return status;
 
 #ifdef CONFIG_PROC_FS
@@ -1087,7 +1083,7 @@ cleanup_netlink_notifier:
 
 static void __exit nfnetlink_queue_fini(void)
 {
-        nf_unregister_queue_handlers(&nfqh);
+        nf_unregister_queue_handler();
         unregister_netdevice_notifier(&nfqnl_dev_notifier);
 #ifdef CONFIG_PROC_FS
         remove_proc_entry("nfnetlink_queue", proc_net_netfilter);