1 files changed, 121 insertions, 0 deletions
diff --git a/net/ipv4/tunnel4.c b/net/ipv4/tunnel4.c
new file mode 100644
index 000000000000..8d30c48f090e
--- /dev/null
+++ b/net/ipv4/tunnel4.c
@@ -0,0 +1,121 @@
+/* tunnel4.c: Generic IP tunnel transformer.
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/icmp.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/xfrm.h>
+
+static struct xfrm_tunnel *tunnel4_handlers;
+static DEFINE_MUTEX(tunnel4_mutex);
+
+int xfrm4_tunnel_register(struct xfrm_tunnel *handler)
+{
+	struct xfrm_tunnel **pprev;
+	int ret = -EEXIST;
+	int priority = handler->priority;
+
+	mutex_lock(&tunnel4_mutex);
+
+	for (pprev = &tunnel4_handlers; *pprev; pprev = &(*pprev)->next) {
+		if ((*pprev)->priority > priority)
+			break;
+		if ((*pprev)->priority == priority)
+			goto err;
+	}
+
+	handler->next = *pprev;
+	*pprev = handler;
+
+	ret = 0;
+
+err:
+	mutex_unlock(&tunnel4_mutex);
+
+	return ret;
+}
+
+EXPORT_SYMBOL(xfrm4_tunnel_register);
+
+int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler)
+{
+	struct xfrm_tunnel **pprev;
+	int ret = -ENOENT;
+
+	mutex_lock(&tunnel4_mutex);
+
+	for (pprev = &tunnel4_handlers; *pprev; pprev = &(*pprev)->next) {
+		if (*pprev == handler) {
+			*pprev = handler->next;
+			ret = 0;
+			break;
+		}
+	}
+
+	mutex_unlock(&tunnel4_mutex);
+
+	synchronize_net();
+
+	return ret;
+}
+
+EXPORT_SYMBOL(xfrm4_tunnel_deregister);
+
+static int tunnel4_rcv(struct sk_buff *skb)
+{
+	struct xfrm_tunnel *handler;
+
+	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		goto drop;
+
+	for (handler = tunnel4_handlers; handler; handler = handler->next)
+		if (!handler->handler(skb))
+			return 0;
+
+	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+static void tunnel4_err(struct sk_buff *skb, u32 info)
+{
+	struct xfrm_tunnel *handler;
+
+	for (handler = tunnel4_handlers; handler; handler = handler->next)
+		if (!handler->err_handler(skb, info))
+			break;
+}
+
+static struct net_protocol tunnel4_protocol = {
+	.handler	=	tunnel4_rcv,
+	.err_handler	=	tunnel4_err,
+	.no_policy	=	1,
+};
+
+static int __init tunnel4_init(void)
+{
+	if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
+		printk(KERN_ERR "tunnel4 init: can't add protocol\n");
+		return -EAGAIN;
+	}
+	return 0;
+}
+
+static void __exit tunnel4_fini(void)
+{
+	if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
+		printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
+}
+
+module_init(tunnel4_init);
+module_exit(tunnel4_fini);
+MODULE_LICENSE("GPL");