GRE: Refactor GRE tunneling code.

Following patch refactors GRE code into ip tunneling code and GRE
specific code. Common tunneling code is moved to ip_tunnel module.
ip_tunnel module is written as generic library which can be used
by different tunneling implementations.

ip_tunnel module contains following components:
 - packet xmit and rcv generic code. xmit flow looks like
   (gre_xmit/ipip_xmit)->ip_tunnel_xmit->ip_local_out.
 - hash table of all devices.
 - lookup for tunnel devices.
 - control plane operations like device create, destroy, ioctl, netlink
   operations code.
 - registration for tunneling modules, like gre, ipip etc.
 - define single pcpu_tstats dev->tstats.
 - struct tnl_ptk_info added to pass parsed tunnel packet parameters.

ipip.h header is renamed to ip_tunnel.h

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 51 insertions, 0 deletions

diff --git a/include/net/gre.h b/include/net/gre.h
index 82665474bcb7..9f03a390c826 100644
--- a/include/net/gre.h
+++ b/include/net/gre.h
@@ -2,6 +2,7 @@
 #define __LINUX_GRE_H
 
 #include <linux/skbuff.h>
+#include <net/ip_tunnels.h>
 
 #define GREPROTO_CISCO          0
 #define GREPROTO_PPTP           1
@@ -12,7 +13,57 @@ struct gre_protocol {
         void (*err_handler)(struct sk_buff *skb, u32 info);
 };
 
+struct gre_base_hdr {
+        __be16 flags;
+        __be16 protocol;
+};
+#define GRE_HEADER_SECTION 4
+
 int gre_add_protocol(const struct gre_protocol *proto, u8 version);
 int gre_del_protocol(const struct gre_protocol *proto, u8 version);
 
+static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
+{
+        __be16 tflags = 0;
+
+        if (flags & GRE_CSUM)
+                tflags |= TUNNEL_CSUM;
+        if (flags & GRE_ROUTING)
+                tflags |= TUNNEL_ROUTING;
+        if (flags & GRE_KEY)
+                tflags |= TUNNEL_KEY;
+        if (flags & GRE_SEQ)
+                tflags |= TUNNEL_SEQ;
+        if (flags & GRE_STRICT)
+                tflags |= TUNNEL_STRICT;
+        if (flags & GRE_REC)
+                tflags |= TUNNEL_REC;
+        if (flags & GRE_VERSION)
+                tflags |= TUNNEL_VERSION;
+
+        return tflags;
+}
+
+static inline __be16 tnl_flags_to_gre_flags(__be16 tflags)
+{
+        __be16 flags = 0;
+
+        if (tflags & TUNNEL_CSUM)
+                flags |= GRE_CSUM;
+        if (tflags & TUNNEL_ROUTING)
+                flags |= GRE_ROUTING;
+        if (tflags & TUNNEL_KEY)
+                flags |= GRE_KEY;
+        if (tflags & TUNNEL_SEQ)
+                flags |= GRE_SEQ;
+        if (tflags & TUNNEL_STRICT)
+                flags |= GRE_STRICT;
+        if (tflags & TUNNEL_REC)
+                flags |= GRE_REC;
+        if (tflags & TUNNEL_VERSION)
+                flags |= GRE_VERSION;
+
+        return flags;
+}
+
 #endif