zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/net/ipv4/gre.c b/ap/os/linux/linux-3.4.x/net/ipv4/gre.c
new file mode 100644
index 0000000..42a4910
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/net/ipv4/gre.c
@@ -0,0 +1,144 @@
+/*
+ * GRE over IPv4 demultiplexer driver
+ *
+ * Authors: Dmitry Kozlov (xeb@mail.ru)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+#include <net/protocol.h>
+#include <net/gre.h>
+
+
+static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
+static DEFINE_SPINLOCK(gre_proto_lock);
+
+int gre_add_protocol(const struct gre_protocol *proto, u8 version)
+{
+ if (version >= GREPROTO_MAX)
+ goto err_out;
+
+ spin_lock(&gre_proto_lock);
+ if (gre_proto[version])
+ goto err_out_unlock;
+
+ RCU_INIT_POINTER(gre_proto[version], proto);
+ spin_unlock(&gre_proto_lock);
+ return 0;
+
+err_out_unlock:
+ spin_unlock(&gre_proto_lock);
+err_out:
+ return -1;
+}
+EXPORT_SYMBOL_GPL(gre_add_protocol);
+
+int gre_del_protocol(const struct gre_protocol *proto, u8 version)
+{
+ if (version >= GREPROTO_MAX)
+ goto err_out;
+
+ spin_lock(&gre_proto_lock);
+ if (rcu_dereference_protected(gre_proto[version],
+ lockdep_is_held(&gre_proto_lock)) != proto)
+ goto err_out_unlock;
+ RCU_INIT_POINTER(gre_proto[version], NULL);
+ spin_unlock(&gre_proto_lock);
+ synchronize_rcu();
+ return 0;
+
+err_out_unlock:
+ spin_unlock(&gre_proto_lock);
+err_out:
+ return -1;
+}
+EXPORT_SYMBOL_GPL(gre_del_protocol);
+
+static int gre_rcv(struct sk_buff *skb)
+{
+ const struct gre_protocol *proto;
+ u8 ver;
+ int ret;
+
+ if (!pskb_may_pull(skb, 12))
+ goto drop;
+
+ ver = skb->data[1]&0x7f;
+ if (ver >= GREPROTO_MAX)
+ goto drop;
+
+ rcu_read_lock();
+ proto = rcu_dereference(gre_proto[ver]);
+ if (!proto || !proto->handler)
+ goto drop_unlock;
+ ret = proto->handler(skb);
+ rcu_read_unlock();
+ return ret;
+
+drop_unlock:
+ rcu_read_unlock();
+drop:
+ kfree_skb(skb);
+ return NET_RX_DROP;
+}
+
+static void gre_err(struct sk_buff *skb, u32 info)
+{
+ const struct gre_protocol *proto;
+ const struct iphdr *iph = (const struct iphdr *)skb->data;
+ u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+
+ if (ver >= GREPROTO_MAX)
+ return;
+
+ rcu_read_lock();
+ proto = rcu_dereference(gre_proto[ver]);
+ if (proto && proto->err_handler)
+ proto->err_handler(skb, info);
+ rcu_read_unlock();
+}
+
+static const struct net_protocol net_gre_protocol = {
+ .handler = gre_rcv,
+ .err_handler = gre_err,
+ .netns_ok = 1,
+};
+
+static int __init gre_init(void)
+{
+ pr_info("GRE over IPv4 demultiplexor driver\n");
+
+ if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
+ pr_err("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 demultiplexer driver");
+MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
+MODULE_LICENSE("GPL");
+