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1 | /* SPDX-License-Identifier: GPL-2.0 */ | |
2 | #ifndef __LINUX_GRE_H | |
3 | #define __LINUX_GRE_H | |
4 | ||
5 | #include <linux/skbuff.h> | |
6 | #include <net/ip_tunnels.h> | |
7 | ||
8 | struct gre_base_hdr { | |
9 | __be16 flags; | |
10 | __be16 protocol; | |
11 | } __packed; | |
12 | ||
13 | struct gre_full_hdr { | |
14 | struct gre_base_hdr fixed_header; | |
15 | __be16 csum; | |
16 | __be16 reserved1; | |
17 | __be32 key; | |
18 | __be32 seq; | |
19 | } __packed; | |
20 | #define GRE_HEADER_SECTION 4 | |
21 | ||
22 | #define GREPROTO_CISCO 0 | |
23 | #define GREPROTO_PPTP 1 | |
24 | #define GREPROTO_MAX 2 | |
25 | #define GRE_IP_PROTO_MAX 2 | |
26 | ||
27 | struct gre_protocol { | |
28 | int (*handler)(struct sk_buff *skb); | |
29 | void (*err_handler)(struct sk_buff *skb, u32 info); | |
30 | }; | |
31 | ||
32 | int gre_add_protocol(const struct gre_protocol *proto, u8 version); | |
33 | int gre_del_protocol(const struct gre_protocol *proto, u8 version); | |
34 | ||
35 | struct net_device *gretap_fb_dev_create(struct net *net, const char *name, | |
36 | u8 name_assign_type); | |
37 | int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, | |
38 | bool *csum_err, __be16 proto, int nhs); | |
39 | ||
40 | static inline int gre_calc_hlen(__be16 o_flags) | |
41 | { | |
42 | int addend = 4; | |
43 | ||
44 | if (o_flags & TUNNEL_CSUM) | |
45 | addend += 4; | |
46 | if (o_flags & TUNNEL_KEY) | |
47 | addend += 4; | |
48 | if (o_flags & TUNNEL_SEQ) | |
49 | addend += 4; | |
50 | return addend; | |
51 | } | |
52 | ||
53 | static inline __be16 gre_flags_to_tnl_flags(__be16 flags) | |
54 | { | |
55 | __be16 tflags = 0; | |
56 | ||
57 | if (flags & GRE_CSUM) | |
58 | tflags |= TUNNEL_CSUM; | |
59 | if (flags & GRE_ROUTING) | |
60 | tflags |= TUNNEL_ROUTING; | |
61 | if (flags & GRE_KEY) | |
62 | tflags |= TUNNEL_KEY; | |
63 | if (flags & GRE_SEQ) | |
64 | tflags |= TUNNEL_SEQ; | |
65 | if (flags & GRE_STRICT) | |
66 | tflags |= TUNNEL_STRICT; | |
67 | if (flags & GRE_REC) | |
68 | tflags |= TUNNEL_REC; | |
69 | if (flags & GRE_VERSION) | |
70 | tflags |= TUNNEL_VERSION; | |
71 | ||
72 | return tflags; | |
73 | } | |
74 | ||
75 | static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags) | |
76 | { | |
77 | __be16 flags = 0; | |
78 | ||
79 | if (tflags & TUNNEL_CSUM) | |
80 | flags |= GRE_CSUM; | |
81 | if (tflags & TUNNEL_ROUTING) | |
82 | flags |= GRE_ROUTING; | |
83 | if (tflags & TUNNEL_KEY) | |
84 | flags |= GRE_KEY; | |
85 | if (tflags & TUNNEL_SEQ) | |
86 | flags |= GRE_SEQ; | |
87 | if (tflags & TUNNEL_STRICT) | |
88 | flags |= GRE_STRICT; | |
89 | if (tflags & TUNNEL_REC) | |
90 | flags |= GRE_REC; | |
91 | if (tflags & TUNNEL_VERSION) | |
92 | flags |= GRE_VERSION; | |
93 | ||
94 | return flags; | |
95 | } | |
96 | ||
97 | static inline __sum16 gre_checksum(struct sk_buff *skb) | |
98 | { | |
99 | __wsum csum; | |
100 | ||
101 | if (skb->ip_summed == CHECKSUM_PARTIAL) | |
102 | csum = lco_csum(skb); | |
103 | else | |
104 | csum = skb_checksum(skb, 0, skb->len, 0); | |
105 | return csum_fold(csum); | |
106 | } | |
107 | ||
108 | static inline void gre_build_header(struct sk_buff *skb, int hdr_len, | |
109 | __be16 flags, __be16 proto, | |
110 | __be32 key, __be32 seq) | |
111 | { | |
112 | struct gre_base_hdr *greh; | |
113 | ||
114 | skb_push(skb, hdr_len); | |
115 | ||
116 | skb_set_inner_protocol(skb, proto); | |
117 | skb_reset_transport_header(skb); | |
118 | greh = (struct gre_base_hdr *)skb->data; | |
119 | greh->flags = gre_tnl_flags_to_gre_flags(flags); | |
120 | greh->protocol = proto; | |
121 | ||
122 | if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) { | |
123 | __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4); | |
124 | ||
125 | if (flags & TUNNEL_SEQ) { | |
126 | *ptr = seq; | |
127 | ptr--; | |
128 | } | |
129 | if (flags & TUNNEL_KEY) { | |
130 | *ptr = key; | |
131 | ptr--; | |
132 | } | |
133 | if (flags & TUNNEL_CSUM && | |
134 | !(skb_shinfo(skb)->gso_type & | |
135 | (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) { | |
136 | *ptr = 0; | |
137 | *(__sum16 *)ptr = gre_checksum(skb); | |
138 | } | |
139 | } | |
140 | } | |
141 | ||
142 | #endif |