1#ifndef __LINUX_GRE_H
2#define __LINUX_GRE_H
3
4#include <linux/skbuff.h>
5#include <net/ip_tunnels.h>
6
7#define GREPROTO_CISCO		0
8#define GREPROTO_PPTP		1
9#define GREPROTO_MAX		2
10#define GRE_IP_PROTO_MAX	2
11
12struct gre_protocol {
13	int  (*handler)(struct sk_buff *skb);
14	void (*err_handler)(struct sk_buff *skb, u32 info);
15};
16
17struct gre_base_hdr {
18	__be16 flags;
19	__be16 protocol;
20};
21#define GRE_HEADER_SECTION 4
22
23int gre_add_protocol(const struct gre_protocol *proto, u8 version);
24int gre_del_protocol(const struct gre_protocol *proto, u8 version);
25
26struct gre_cisco_protocol {
27	int (*handler)(struct sk_buff *skb, const struct tnl_ptk_info *tpi);
28	int (*err_handler)(struct sk_buff *skb, u32 info,
29			   const struct tnl_ptk_info *tpi);
30	u8 priority;
31};
32
33int gre_cisco_register(struct gre_cisco_protocol *proto);
34int gre_cisco_unregister(struct gre_cisco_protocol *proto);
35
36void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
37		      int hdr_len);
38
39static inline struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
40						  bool csum)
41{
42	return iptunnel_handle_offloads(skb, csum,
43					csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
44}
45
46
47static inline int ip_gre_calc_hlen(__be16 o_flags)
48{
49	int addend = 4;
50
51	if (o_flags&TUNNEL_CSUM)
52		addend += 4;
53	if (o_flags&TUNNEL_KEY)
54		addend += 4;
55	if (o_flags&TUNNEL_SEQ)
56		addend += 4;
57	return addend;
58}
59
60static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
61{
62	__be16 tflags = 0;
63
64	if (flags & GRE_CSUM)
65		tflags |= TUNNEL_CSUM;
66	if (flags & GRE_ROUTING)
67		tflags |= TUNNEL_ROUTING;
68	if (flags & GRE_KEY)
69		tflags |= TUNNEL_KEY;
70	if (flags & GRE_SEQ)
71		tflags |= TUNNEL_SEQ;
72	if (flags & GRE_STRICT)
73		tflags |= TUNNEL_STRICT;
74	if (flags & GRE_REC)
75		tflags |= TUNNEL_REC;
76	if (flags & GRE_VERSION)
77		tflags |= TUNNEL_VERSION;
78
79	return tflags;
80}
81
82static inline __be16 tnl_flags_to_gre_flags(__be16 tflags)
83{
84	__be16 flags = 0;
85
86	if (tflags & TUNNEL_CSUM)
87		flags |= GRE_CSUM;
88	if (tflags & TUNNEL_ROUTING)
89		flags |= GRE_ROUTING;
90	if (tflags & TUNNEL_KEY)
91		flags |= GRE_KEY;
92	if (tflags & TUNNEL_SEQ)
93		flags |= GRE_SEQ;
94	if (tflags & TUNNEL_STRICT)
95		flags |= GRE_STRICT;
96	if (tflags & TUNNEL_REC)
97		flags |= GRE_REC;
98	if (tflags & TUNNEL_VERSION)
99		flags |= GRE_VERSION;
100
101	return flags;
102}
103
104#endif
105