4 #include <linux/skbuff.h>
5 #include <net/ip_tunnels.h>
13 struct gre_base_hdr fixed_header
;
19 #define GRE_HEADER_SECTION 4
21 #define GREPROTO_CISCO 0
22 #define GREPROTO_PPTP 1
23 #define GREPROTO_MAX 2
24 #define GRE_IP_PROTO_MAX 2
27 int (*handler
)(struct sk_buff
*skb
);
28 void (*err_handler
)(struct sk_buff
*skb
, u32 info
);
31 int gre_add_protocol(const struct gre_protocol
*proto
, u8 version
);
32 int gre_del_protocol(const struct gre_protocol
*proto
, u8 version
);
34 struct net_device
*gretap_fb_dev_create(struct net
*net
, const char *name
,
36 int gre_parse_header(struct sk_buff
*skb
, struct tnl_ptk_info
*tpi
,
37 bool *csum_err
, __be16 proto
, int nhs
);
39 static inline int gre_calc_hlen(__be16 o_flags
)
43 if (o_flags
& TUNNEL_CSUM
)
45 if (o_flags
& TUNNEL_KEY
)
47 if (o_flags
& TUNNEL_SEQ
)
52 static inline __be16
gre_flags_to_tnl_flags(__be16 flags
)
57 tflags
|= TUNNEL_CSUM
;
58 if (flags
& GRE_ROUTING
)
59 tflags
|= TUNNEL_ROUTING
;
64 if (flags
& GRE_STRICT
)
65 tflags
|= TUNNEL_STRICT
;
68 if (flags
& GRE_VERSION
)
69 tflags
|= TUNNEL_VERSION
;
74 static inline __be16
gre_tnl_flags_to_gre_flags(__be16 tflags
)
78 if (tflags
& TUNNEL_CSUM
)
80 if (tflags
& TUNNEL_ROUTING
)
82 if (tflags
& TUNNEL_KEY
)
84 if (tflags
& TUNNEL_SEQ
)
86 if (tflags
& TUNNEL_STRICT
)
88 if (tflags
& TUNNEL_REC
)
90 if (tflags
& TUNNEL_VERSION
)
96 static inline __sum16
gre_checksum(struct sk_buff
*skb
)
100 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
101 csum
= lco_csum(skb
);
103 csum
= skb_checksum(skb
, 0, skb
->len
, 0);
104 return csum_fold(csum
);
107 static inline void gre_build_header(struct sk_buff
*skb
, int hdr_len
,
108 __be16 flags
, __be16 proto
,
109 __be32 key
, __be32 seq
)
111 struct gre_base_hdr
*greh
;
113 skb_push(skb
, hdr_len
);
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
;
121 if (flags
& (TUNNEL_KEY
| TUNNEL_CSUM
| TUNNEL_SEQ
)) {
122 __be32
*ptr
= (__be32
*)(((u8
*)greh
) + hdr_len
- 4);
124 if (flags
& TUNNEL_SEQ
) {
128 if (flags
& TUNNEL_KEY
) {
132 if (flags
& TUNNEL_CSUM
&&
133 !(skb_shinfo(skb
)->gso_type
&
134 (SKB_GSO_GRE
| SKB_GSO_GRE_CSUM
))) {
136 *(__sum16
*)ptr
= gre_checksum(skb
);