1 files changed, 140 insertions, 0 deletions
diff --git a/kernel/driver/gre.c b/kernel/driver/gre.c
new file mode 100644
index 0000000..cda0576
--- /dev/null
+++ b/kernel/driver/gre.c
@@ -0,0 +1,140 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/netdevice.h>
+#include <linux/version.h>
+#include <linux/spinlock.h>
+#include <net/protocol.h>
+
+#include "gre.h"
+
+
+struct gre_protocol *gre_proto[GREPROTO_MAX] ____cacheline_aligned_in_smp;
+static DEFINE_RWLOCK(gre_proto_lock);
+
+int gre_add_protocol(struct gre_protocol *proto, u8 version)
+{
+	int ret;
+
+	if (version >= GREPROTO_MAX)
+		return -1;
+	
+	write_lock_bh(&gre_proto_lock);
+	if (gre_proto[version]) {
+		ret = -1;
+	} else {
+		gre_proto[version]=proto;
+		ret = 0;
+	}
+	write_unlock_bh(&gre_proto_lock);
+
+	return ret;
+}
+int gre_del_protocol(struct gre_protocol *proto, u8 version)
+{
+	int ret;
+
+	if (version >= GREPROTO_MAX)
+		return -1;
+
+	write_lock_bh(&gre_proto_lock);
+	if (gre_proto[version] == proto) {
+		gre_proto[version] = NULL;
+		ret = 0;
+	} else {
+		ret = -1;
+	}
+	write_unlock_bh(&gre_proto_lock);
+
+	return ret;
+}
+static int gre_rcv(struct sk_buff *skb)
+{
+	u8 ver;
+	int ret;
+
+	if (!pskb_may_pull(skb, 12))
+		goto drop_nolock;
+
+	ver = skb->data[1]&0x7f;
+	if (ver >= GREPROTO_MAX)
+		goto drop_nolock;
+	
+	read_lock(&gre_proto_lock);
+	if (!gre_proto[ver] || !gre_proto[ver]->handler)
+		goto drop;
+
+	ret = gre_proto[ver]->handler(skb);
+	read_unlock(&gre_proto_lock);
+
+	return ret;
+
+drop:
+	read_unlock(&gre_proto_lock);
+drop_nolock:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+static void gre_err(struct sk_buff *skb, u32 info)
+{
+	u8 ver;
+
+	printk("err\n");
+
+	if (!pskb_may_pull(skb, 12))
+		goto drop_nolock;
+
+	ver=skb->data[1];
+	if (ver>=GREPROTO_MAX)
+		goto drop_nolock;
+		
+	read_lock(&gre_proto_lock);
+	if (!gre_proto[ver] || !gre_proto[ver]->err_handler)
+		goto drop;
+
+	gre_proto[ver]->err_handler(skb,info);
+	read_unlock(&gre_proto_lock);
+
+	return;
+
+drop:
+	read_unlock(&gre_proto_lock);
+drop_nolock:
+	kfree_skb(skb);
+}
+
+
+static struct net_protocol net_gre_protocol = {
+	.handler	= gre_rcv,
+	.err_handler	=	gre_err,
+//	.netns_ok=1,
+};
+
+static int __init gre_init(void)
+{
+	printk(KERN_INFO "GRE over IPv4 demultiplexor driver");
+	
+	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
+		printk(KERN_INFO "gre: can't add protocol\n");
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static void __exit gre_exit(void)
+{
+	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
+}
+
+module_init(gre_init);
+module_exit(gre_exit);
+
+MODULE_DESCRIPTION("GRE over IPv4 demultiplexor driver");
+MODULE_AUTHOR("Kozlov D. (xeb@mail.ru)");
+MODULE_LICENSE("GPL");
+EXPORT_SYMBOL_GPL(gre_add_protocol);
+EXPORT_SYMBOL_GPL(gre_del_protocol);
+