1 files changed, 356 insertions, 0 deletions
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
new file mode 100644
index 000000000..e2f334f70
--- /dev/null
+++ b/net/netfilter/nf_queue.c
@@ -0,0 +1,356 @@
+/*
+ * Rusty Russell (C)2000 -- This code is GPL.
+ * Patrick McHardy (c) 2006-2012
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/seq_file.h>
+#include <linux/rcupdate.h>
+#include <net/protocol.h>
+#include <net/netfilter/nf_queue.h>
+#include <net/dst.h>
+
+#include "nf_internals.h"
+
+static const struct nf_queue_handler __rcu *nf_queue_handler;
+
+/*
+ * 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.
+ */
+
+void nf_register_queue_handler(const struct nf_queue_handler *qh)
+{
+	/* should never happen, we only have one queueing backend in kernel */
+	WARN_ON(rcu_access_pointer(nf_queue_handler));
+	rcu_assign_pointer(nf_queue_handler, qh);
+}
+EXPORT_SYMBOL(nf_register_queue_handler);
+
+/* The caller must flush their queue before this */
+void nf_unregister_queue_handler(void)
+{
+	RCU_INIT_POINTER(nf_queue_handler, NULL);
+}
+EXPORT_SYMBOL(nf_unregister_queue_handler);
+
+static void nf_queue_sock_put(struct sock *sk)
+{
+#ifdef CONFIG_INET
+	sock_gen_put(sk);
+#else
+	sock_put(sk);
+#endif
+}
+
+static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
+{
+	struct nf_hook_state *state = &entry->state;
+
+	/* Release those devices we held, or Alexey will kill me. */
+	dev_put(state->in);
+	dev_put(state->out);
+	if (state->sk)
+		nf_queue_sock_put(state->sk);
+
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+	dev_put(entry->physin);
+	dev_put(entry->physout);
+#endif
+}
+
+void nf_queue_entry_free(struct nf_queue_entry *entry)
+{
+	nf_queue_entry_release_refs(entry);
+	kfree(entry);
+}
+EXPORT_SYMBOL_GPL(nf_queue_entry_free);
+
+static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
+{
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+	const struct sk_buff *skb = entry->skb;
+
+	if (nf_bridge_info_exists(skb)) {
+		entry->physin = nf_bridge_get_physindev(skb, entry->state.net);
+		entry->physout = nf_bridge_get_physoutdev(skb);
+	} else {
+		entry->physin = NULL;
+		entry->physout = NULL;
+	}
+#endif
+}
+
+/* Bump dev refs so they don't vanish while packet is out */
+bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
+{
+	struct nf_hook_state *state = &entry->state;
+
+	if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
+		return false;
+
+	dev_hold(state->in);
+	dev_hold(state->out);
+
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+	dev_hold(entry->physin);
+	dev_hold(entry->physout);
+#endif
+	return true;
+}
+EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
+
+void nf_queue_nf_hook_drop(struct net *net)
+{
+	const struct nf_queue_handler *qh;
+
+	rcu_read_lock();
+	qh = rcu_dereference(nf_queue_handler);
+	if (qh)
+		qh->nf_hook_drop(net);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
+
+static void nf_ip_saveroute(const struct sk_buff *skb,
+			    struct nf_queue_entry *entry)
+{
+	struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
+
+	if (entry->state.hook == NF_INET_LOCAL_OUT) {
+		const struct iphdr *iph = ip_hdr(skb);
+
+		rt_info->tos = iph->tos;
+		rt_info->daddr = iph->daddr;
+		rt_info->saddr = iph->saddr;
+		rt_info->mark = skb->mark;
+	}
+}
+
+static void nf_ip6_saveroute(const struct sk_buff *skb,
+			     struct nf_queue_entry *entry)
+{
+	struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
+
+	if (entry->state.hook == NF_INET_LOCAL_OUT) {
+		const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+		rt_info->daddr = iph->daddr;
+		rt_info->saddr = iph->saddr;
+		rt_info->mark = skb->mark;
+	}
+}
+
+static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
+		      unsigned int index, unsigned int queuenum)
+{
+	struct nf_queue_entry *entry = NULL;
+	const struct nf_queue_handler *qh;
+	unsigned int route_key_size;
+	int status;
+
+	/* QUEUE == DROP if no one is waiting, to be safe. */
+	qh = rcu_dereference(nf_queue_handler);
+	if (!qh)
+		return -ESRCH;
+
+	switch (state->pf) {
+	case AF_INET:
+		route_key_size = sizeof(struct ip_rt_info);
+		break;
+	case AF_INET6:
+		route_key_size = sizeof(struct ip6_rt_info);
+		break;
+	default:
+		route_key_size = 0;
+		break;
+	}
+
+	if (skb_sk_is_prefetched(skb)) {
+		struct sock *sk = skb->sk;
+
+		if (!sk_is_refcounted(sk)) {
+			if (!refcount_inc_not_zero(&sk->sk_refcnt))
+				return -ENOTCONN;
+
+			/* drop refcount on skb_orphan */
+			skb->destructor = sock_edemux;
+		}
+	}
+
+	entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
+	if (!entry)
+		return -ENOMEM;
+
+	if (skb_dst(skb) && !skb_dst_force(skb)) {
+		kfree(entry);
+		return -ENETDOWN;
+	}
+
+	*entry = (struct nf_queue_entry) {
+		.skb	= skb,
+		.state	= *state,
+		.hook_index = index,
+		.size	= sizeof(*entry) + route_key_size,
+	};
+
+	__nf_queue_entry_init_physdevs(entry);
+
+	if (!nf_queue_entry_get_refs(entry)) {
+		kfree(entry);
+		return -ENOTCONN;
+	}
+
+	switch (entry->state.pf) {
+	case AF_INET:
+		nf_ip_saveroute(skb, entry);
+		break;
+	case AF_INET6:
+		nf_ip6_saveroute(skb, entry);
+		break;
+	}
+
+	status = qh->outfn(entry, queuenum);
+	if (status < 0) {
+		nf_queue_entry_free(entry);
+		return status;
+	}
+
+	return 0;
+}
+
+/* Packets leaving via this function must come back through nf_reinject(). */
+int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
+	     unsigned int index, unsigned int verdict)
+{
+	int ret;
+
+	ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
+	if (ret < 0) {
+		if (ret == -ESRCH &&
+		    (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
+			return 1;
+		kfree_skb(skb);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_queue);
+
+static unsigned int nf_iterate(struct sk_buff *skb,
+			       struct nf_hook_state *state,
+			       const struct nf_hook_entries *hooks,
+			       unsigned int *index)
+{
+	const struct nf_hook_entry *hook;
+	unsigned int verdict, i = *index;
+
+	while (i < hooks->num_hook_entries) {
+		hook = &hooks->hooks[i];
+repeat:
+		verdict = nf_hook_entry_hookfn(hook, skb, state);
+		if (verdict != NF_ACCEPT) {
+			*index = i;
+			if (verdict != NF_REPEAT)
+				return verdict;
+			goto repeat;
+		}
+		i++;
+	}
+
+	*index = i;
+	return NF_ACCEPT;
+}
+
+static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
+{
+	switch (pf) {
+#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
+	case NFPROTO_BRIDGE:
+		return rcu_dereference(net->nf.hooks_bridge[hooknum]);
+#endif
+	case NFPROTO_IPV4:
+		return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
+	case NFPROTO_IPV6:
+		return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
+	default:
+		WARN_ON_ONCE(1);
+		return NULL;
+	}
+
+	return NULL;
+}
+
+/* Caller must hold rcu read-side lock */
+void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
+{
+	const struct nf_hook_entry *hook_entry;
+	const struct nf_hook_entries *hooks;
+	struct sk_buff *skb = entry->skb;
+	const struct net *net;
+	unsigned int i;
+	int err;
+	u8 pf;
+
+	net = entry->state.net;
+	pf = entry->state.pf;
+
+	hooks = nf_hook_entries_head(net, pf, entry->state.hook);
+
+	i = entry->hook_index;
+	if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
+		kfree_skb(skb);
+		nf_queue_entry_free(entry);
+		return;
+	}
+
+	hook_entry = &hooks->hooks[i];
+
+	/* Continue traversal iff userspace said ok... */
+	if (verdict == NF_REPEAT)
+		verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
+
+	if (verdict == NF_ACCEPT) {
+		if (nf_reroute(skb, entry) < 0)
+			verdict = NF_DROP;
+	}
+
+	if (verdict == NF_ACCEPT) {
+next_hook:
+		++i;
+		verdict = nf_iterate(skb, &entry->state, hooks, &i);
+	}
+
+	switch (verdict & NF_VERDICT_MASK) {
+	case NF_ACCEPT:
+	case NF_STOP:
+		local_bh_disable();
+		entry->state.okfn(entry->state.net, entry->state.sk, skb);
+		local_bh_enable();
+		break;
+	case NF_QUEUE:
+		err = nf_queue(skb, &entry->state, i, verdict);
+		if (err == 1)
+			goto next_hook;
+		break;
+	case NF_STOLEN:
+		break;
+	default:
+		kfree_skb(skb);
+	}
+
+	nf_queue_entry_free(entry);
+}
+EXPORT_SYMBOL(nf_reinject);