1#ifndef __LINUX_GRE_H
 2#define __LINUX_GRE_H
 3
 4#include <linux/skbuff.h>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 5
 6#define GREPROTO_CISCO		0
 7#define GREPROTO_PPTP		1
 8#define GREPROTO_MAX		2
 
 9
10struct gre_protocol {
11	int  (*handler)(struct sk_buff *skb);
12	void (*err_handler)(struct sk_buff *skb, u32 info);
13};
14
15int gre_add_protocol(const struct gre_protocol *proto, u8 version);
16int gre_del_protocol(const struct gre_protocol *proto, u8 version);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
17
18#endif

  1#ifndef __LINUX_GRE_H
  2#define __LINUX_GRE_H
  3
  4#include <linux/skbuff.h>
  5#include <net/ip_tunnels.h>
  6
  7struct gre_base_hdr {
  8	__be16 flags;
  9	__be16 protocol;
 10} __packed;
 11
 12struct gre_full_hdr {
 13	struct gre_base_hdr fixed_header;
 14	__be16 csum;
 15	__be16 reserved1;
 16	__be32 key;
 17	__be32 seq;
 18} __packed;
 19#define GRE_HEADER_SECTION 4
 20
 21#define GREPROTO_CISCO		0
 22#define GREPROTO_PPTP		1
 23#define GREPROTO_MAX		2
 24#define GRE_IP_PROTO_MAX	2
 25
 26struct gre_protocol {
 27	int  (*handler)(struct sk_buff *skb);
 28	void (*err_handler)(struct sk_buff *skb, u32 info);
 29};
 30
 31int gre_add_protocol(const struct gre_protocol *proto, u8 version);
 32int gre_del_protocol(const struct gre_protocol *proto, u8 version);
 33
 34struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
 35				       u8 name_assign_type);
 36int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 37		     bool *csum_err, __be16 proto, int nhs);
 38
 39static inline int gre_calc_hlen(__be16 o_flags)
 40{
 41	int addend = 4;
 42
 43	if (o_flags & TUNNEL_CSUM)
 44		addend += 4;
 45	if (o_flags & TUNNEL_KEY)
 46		addend += 4;
 47	if (o_flags & TUNNEL_SEQ)
 48		addend += 4;
 49	return addend;
 50}
 51
 52static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
 53{
 54	__be16 tflags = 0;
 55
 56	if (flags & GRE_CSUM)
 57		tflags |= TUNNEL_CSUM;
 58	if (flags & GRE_ROUTING)
 59		tflags |= TUNNEL_ROUTING;
 60	if (flags & GRE_KEY)
 61		tflags |= TUNNEL_KEY;
 62	if (flags & GRE_SEQ)
 63		tflags |= TUNNEL_SEQ;
 64	if (flags & GRE_STRICT)
 65		tflags |= TUNNEL_STRICT;
 66	if (flags & GRE_REC)
 67		tflags |= TUNNEL_REC;
 68	if (flags & GRE_VERSION)
 69		tflags |= TUNNEL_VERSION;
 70
 71	return tflags;
 72}
 73
 74static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
 75{
 76	__be16 flags = 0;
 77
 78	if (tflags & TUNNEL_CSUM)
 79		flags |= GRE_CSUM;
 80	if (tflags & TUNNEL_ROUTING)
 81		flags |= GRE_ROUTING;
 82	if (tflags & TUNNEL_KEY)
 83		flags |= GRE_KEY;
 84	if (tflags & TUNNEL_SEQ)
 85		flags |= GRE_SEQ;
 86	if (tflags & TUNNEL_STRICT)
 87		flags |= GRE_STRICT;
 88	if (tflags & TUNNEL_REC)
 89		flags |= GRE_REC;
 90	if (tflags & TUNNEL_VERSION)
 91		flags |= GRE_VERSION;
 92
 93	return flags;
 94}
 95
 96static inline __sum16 gre_checksum(struct sk_buff *skb)
 97{
 98	__wsum csum;
 99
100	if (skb->ip_summed == CHECKSUM_PARTIAL)
101		csum = lco_csum(skb);
102	else
103		csum = skb_checksum(skb, 0, skb->len, 0);
104	return csum_fold(csum);
105}
106
107static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
108				    __be16 flags, __be16 proto,
109				    __be32 key, __be32 seq)
110{
111	struct gre_base_hdr *greh;
112
113	skb_push(skb, hdr_len);
114
115	skb_set_inner_protocol(skb, proto);
116	skb_reset_transport_header(skb);
117	greh = (struct gre_base_hdr *)skb->data;
118	greh->flags = gre_tnl_flags_to_gre_flags(flags);
119	greh->protocol = proto;
120
121	if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
122		__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
123
124		if (flags & TUNNEL_SEQ) {
125			*ptr = seq;
126			ptr--;
127		}
128		if (flags & TUNNEL_KEY) {
129			*ptr = key;
130			ptr--;
131		}
132		if (flags & TUNNEL_CSUM &&
133		    !(skb_shinfo(skb)->gso_type &
134		      (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
135			*ptr = 0;
136			*(__sum16 *)ptr = gre_checksum(skb);
137		}
138	}
139}
140
141#endif