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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
8struct gre_base_hdr {
9 __be16 flags;
10 __be16 protocol;
11} __packed;
12
13struct 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
27struct gre_protocol {
28 int (*handler)(struct sk_buff *skb);
29 void (*err_handler)(struct sk_buff *skb, u32 info);
30};
31
32int gre_add_protocol(const struct gre_protocol *proto, u8 version);
33int gre_del_protocol(const struct gre_protocol *proto, u8 version);
34
35struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
36 u8 name_assign_type);
37int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
38 bool *csum_err, __be16 proto, int nhs);
39
40static inline bool netif_is_gretap(const struct net_device *dev)
41{
42 return dev->rtnl_link_ops &&
43 !strcmp(dev->rtnl_link_ops->kind, "gretap");
44}
45
46static inline bool netif_is_ip6gretap(const struct net_device *dev)
47{
48 return dev->rtnl_link_ops &&
49 !strcmp(dev->rtnl_link_ops->kind, "ip6gretap");
50}
51
52static inline int gre_calc_hlen(const unsigned long *o_flags)
53{
54 int addend = 4;
55
56 if (test_bit(IP_TUNNEL_CSUM_BIT, o_flags))
57 addend += 4;
58 if (test_bit(IP_TUNNEL_KEY_BIT, o_flags))
59 addend += 4;
60 if (test_bit(IP_TUNNEL_SEQ_BIT, o_flags))
61 addend += 4;
62 return addend;
63}
64
65static inline void gre_flags_to_tnl_flags(unsigned long *dst, __be16 flags)
66{
67 IP_TUNNEL_DECLARE_FLAGS(res) = { };
68
69 __assign_bit(IP_TUNNEL_CSUM_BIT, res, flags & GRE_CSUM);
70 __assign_bit(IP_TUNNEL_ROUTING_BIT, res, flags & GRE_ROUTING);
71 __assign_bit(IP_TUNNEL_KEY_BIT, res, flags & GRE_KEY);
72 __assign_bit(IP_TUNNEL_SEQ_BIT, res, flags & GRE_SEQ);
73 __assign_bit(IP_TUNNEL_STRICT_BIT, res, flags & GRE_STRICT);
74 __assign_bit(IP_TUNNEL_REC_BIT, res, flags & GRE_REC);
75 __assign_bit(IP_TUNNEL_VERSION_BIT, res, flags & GRE_VERSION);
76
77 ip_tunnel_flags_copy(dst, res);
78}
79
80static inline __be16 gre_tnl_flags_to_gre_flags(const unsigned long *tflags)
81{
82 __be16 flags = 0;
83
84 if (test_bit(IP_TUNNEL_CSUM_BIT, tflags))
85 flags |= GRE_CSUM;
86 if (test_bit(IP_TUNNEL_ROUTING_BIT, tflags))
87 flags |= GRE_ROUTING;
88 if (test_bit(IP_TUNNEL_KEY_BIT, tflags))
89 flags |= GRE_KEY;
90 if (test_bit(IP_TUNNEL_SEQ_BIT, tflags))
91 flags |= GRE_SEQ;
92 if (test_bit(IP_TUNNEL_STRICT_BIT, tflags))
93 flags |= GRE_STRICT;
94 if (test_bit(IP_TUNNEL_REC_BIT, tflags))
95 flags |= GRE_REC;
96 if (test_bit(IP_TUNNEL_VERSION_BIT, tflags))
97 flags |= GRE_VERSION;
98
99 return flags;
100}
101
102static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
103 const unsigned long *flags, __be16 proto,
104 __be32 key, __be32 seq)
105{
106 IP_TUNNEL_DECLARE_FLAGS(cond) = { };
107 struct gre_base_hdr *greh;
108
109 skb_push(skb, hdr_len);
110
111 skb_set_inner_protocol(skb, proto);
112 skb_reset_transport_header(skb);
113 greh = (struct gre_base_hdr *)skb->data;
114 greh->flags = gre_tnl_flags_to_gre_flags(flags);
115 greh->protocol = proto;
116
117 __set_bit(IP_TUNNEL_KEY_BIT, cond);
118 __set_bit(IP_TUNNEL_CSUM_BIT, cond);
119 __set_bit(IP_TUNNEL_SEQ_BIT, cond);
120
121 if (ip_tunnel_flags_intersect(flags, cond)) {
122 __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
123
124 if (test_bit(IP_TUNNEL_SEQ_BIT, flags)) {
125 *ptr = seq;
126 ptr--;
127 }
128 if (test_bit(IP_TUNNEL_KEY_BIT, flags)) {
129 *ptr = key;
130 ptr--;
131 }
132 if (test_bit(IP_TUNNEL_CSUM_BIT, flags) &&
133 !(skb_shinfo(skb)->gso_type &
134 (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
135 *ptr = 0;
136 if (skb->ip_summed == CHECKSUM_PARTIAL) {
137 *(__sum16 *)ptr = csum_fold(lco_csum(skb));
138 } else {
139 skb->ip_summed = CHECKSUM_PARTIAL;
140 skb->csum_start = skb_transport_header(skb) - skb->head;
141 skb->csum_offset = sizeof(*greh);
142 }
143 }
144 }
145}
146
147#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