1 files changed, 357 insertions, 0 deletions
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
new file mode 100644
index 0000000..4f2310c
--- /dev/null
+++ b/net/netfilter/nf_queue.c
@@ -0,0 +1,357 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <linux/seq_file.h>
+#include <linux/rcupdate.h>
+#include <net/protocol.h>
+#include <net/netfilter/nf_queue.h>
+
+#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.
+ */
+static const struct nf_queue_handler *queue_handler[NFPROTO_NUMPROTO] __read_mostly;
+
+static DEFINE_MUTEX(queue_handler_mutex);
+
+/* 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)
+{
+	int ret;
+
+	if (pf >= ARRAY_SIZE(queue_handler))
+		return -EINVAL;
+
+	mutex_lock(&queue_handler_mutex);
+	if (queue_handler[pf] == qh)
+		ret = -EEXIST;
+	else if (queue_handler[pf])
+		ret = -EBUSY;
+	else {
+		rcu_assign_pointer(queue_handler[pf], qh);
+		ret = 0;
+	}
+	mutex_unlock(&queue_handler_mutex);
+
+	return ret;
+}
+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)
+{
+	if (pf >= ARRAY_SIZE(queue_handler))
+		return -EINVAL;
+
+	mutex_lock(&queue_handler_mutex);
+	if (queue_handler[pf] && queue_handler[pf] != qh) {
+		mutex_unlock(&queue_handler_mutex);
+		return -EINVAL;
+	}
+
+	rcu_assign_pointer(queue_handler[pf], NULL);
+	mutex_unlock(&queue_handler_mutex);
+
+	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 (queue_handler[pf] == qh)
+			rcu_assign_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. */
+	if (entry->indev)
+		dev_put(entry->indev);
+	if (entry->outdev)
+		dev_put(entry->outdev);
+#ifdef CONFIG_BRIDGE_NETFILTER
+	if (entry->skb->nf_bridge) {
+		struct nf_bridge_info *nf_bridge = entry->skb->nf_bridge;
+
+		if (nf_bridge->physindev)
+			dev_put(nf_bridge->physindev);
+		if (nf_bridge->physoutdev)
+			dev_put(nf_bridge->physoutdev);
+	}
+#endif
+	/* Drop reference to owner of hook which queued us. */
+	module_put(entry->elem->owner);
+}
+
+/*
+ * Any packet that leaves via this function must come back
+ * through nf_reinject().
+ */
+static int __nf_queue(struct sk_buff *skb,
+		      struct list_head *elem,
+		      u_int8_t pf, unsigned int hook,
+		      struct net_device *indev,
+		      struct net_device *outdev,
+		      int (*okfn)(struct sk_buff *),
+		      unsigned int queuenum)
+{
+	int status;
+	struct nf_queue_entry *entry = NULL;
+#ifdef CONFIG_BRIDGE_NETFILTER
+	struct net_device *physindev;
+	struct net_device *physoutdev;
+#endif
+	const struct nf_afinfo *afinfo;
+	const struct nf_queue_handler *qh;
+
+	/* QUEUE == DROP if noone is waiting, to be safe. */
+	rcu_read_lock();
+
+	qh = rcu_dereference(queue_handler[pf]);
+	if (!qh)
+		goto err_unlock;
+
+	afinfo = nf_get_afinfo(pf);
+	if (!afinfo)
+		goto err_unlock;
+
+	entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
+	if (!entry)
+		goto err_unlock;
+
+	*entry = (struct nf_queue_entry) {
+		.skb	= skb,
+		.elem	= list_entry(elem, struct nf_hook_ops, list),
+		.pf	= pf,
+		.hook	= hook,
+		.indev	= indev,
+		.outdev	= outdev,
+		.okfn	= okfn,
+	};
+
+	/* If it's going away, ignore hook. */
+	if (!try_module_get(entry->elem->owner)) {
+		rcu_read_unlock();
+		kfree(entry);
+		return 0;
+	}
+
+	/* Bump dev refs so they don't vanish while packet is out */
+	if (indev)
+		dev_hold(indev);
+	if (outdev)
+		dev_hold(outdev);
+#ifdef CONFIG_BRIDGE_NETFILTER
+	if (skb->nf_bridge) {
+		physindev = skb->nf_bridge->physindev;
+		if (physindev)
+			dev_hold(physindev);
+		physoutdev = skb->nf_bridge->physoutdev;
+		if (physoutdev)
+			dev_hold(physoutdev);
+	}
+#endif
+	afinfo->saveroute(skb, entry);
+	status = qh->outfn(entry, queuenum);
+
+	rcu_read_unlock();
+
+	if (status < 0) {
+		nf_queue_entry_release_refs(entry);
+		goto err;
+	}
+
+	return 1;
+
+err_unlock:
+	rcu_read_unlock();
+err:
+	kfree_skb(skb);
+	kfree(entry);
+	return 1;
+}
+
+int nf_queue(struct sk_buff *skb,
+	     struct list_head *elem,
+	     u_int8_t pf, unsigned int hook,
+	     struct net_device *indev,
+	     struct net_device *outdev,
+	     int (*okfn)(struct sk_buff *),
+	     unsigned int queuenum)
+{
+	struct sk_buff *segs;
+
+	if (!skb_is_gso(skb))
+		return __nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
+				  queuenum);
+
+	switch (pf) {
+	case AF_INET:
+		skb->protocol = htons(ETH_P_IP);
+		break;
+	case AF_INET6:
+		skb->protocol = htons(ETH_P_IPV6);
+		break;
+	}
+
+	segs = skb_gso_segment(skb, 0);
+	kfree_skb(skb);
+	if (IS_ERR(segs))
+		return 1;
+
+	do {
+		struct sk_buff *nskb = segs->next;
+
+		segs->next = NULL;
+		if (!__nf_queue(segs, elem, pf, hook, indev, outdev, okfn,
+				queuenum))
+			kfree_skb(segs);
+		segs = nskb;
+	} while (segs);
+	return 1;
+}
+
+void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
+{
+	struct sk_buff *skb = entry->skb;
+	struct list_head *elem = &entry->elem->list;
+	const struct nf_afinfo *afinfo;
+
+	rcu_read_lock();
+
+	nf_queue_entry_release_refs(entry);
+
+	/* Continue traversal iff userspace said ok... */
+	if (verdict == NF_REPEAT) {
+		elem = elem->prev;
+		verdict = NF_ACCEPT;
+	}
+
+	if (verdict == NF_ACCEPT) {
+		afinfo = nf_get_afinfo(entry->pf);
+		if (!afinfo || afinfo->reroute(skb, entry) < 0)
+			verdict = NF_DROP;
+	}
+
+	if (verdict == NF_ACCEPT) {
+	next_hook:
+		verdict = nf_iterate(&nf_hooks[entry->pf][entry->hook],
+				     skb, entry->hook,
+				     entry->indev, entry->outdev, &elem,
+				     entry->okfn, INT_MIN);
+	}
+
+	switch (verdict & NF_VERDICT_MASK) {
+	case NF_ACCEPT:
+	case NF_STOP:
+		local_bh_disable();
+		entry->okfn(skb);
+		local_bh_enable();
+	case NF_STOLEN:
+		break;
+	case NF_QUEUE:
+		if (!__nf_queue(skb, elem, entry->pf, entry->hook,
+				entry->indev, entry->outdev, entry->okfn,
+				verdict >> NF_VERDICT_BITS))
+			goto next_hook;
+		break;
+	default:
+		kfree_skb(skb);
+	}
+	rcu_read_unlock();
+	kfree(entry);
+	return;
+}
+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;
+}
+