Merge branch 'master' into csb1725

[mv-sheeva.git] / net / ipv4 / gre.c

diff --git a/net/ipv4/gre.c b/net/ipv4/gre.c
new file mode 100644 (file)
index 0000000..c6933f2
--- /dev/null
+++ b/net/ipv4/gre.c
@@ -0,0 +1,152 @@
+/*
+ *     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.
+ *
+ */
+
+#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 <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_assign_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_assign_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;
+       u8 ver;
+
+       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->err_handler)
+               goto drop_unlock;
+       proto->err_handler(skb, info);
+       rcu_read_unlock();
+       return;
+
+drop_unlock:
+       rcu_read_unlock();
+drop:
+       kfree_skb(skb);
+}
+
+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");
+
+       if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
+               pr_err("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 demultiplexer driver");
+MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
+MODULE_LICENSE("GPL");
+