1 /* SPDX-License-Identifier: GPL-2.0 */
5 #include <linux/skbuff.h>
6 #include <net/ip_tunnels.h>
14 struct gre_base_hdr fixed_header;
20 #define GRE_HEADER_SECTION 4
22 #define GREPROTO_CISCO 0
23 #define GREPROTO_PPTP 1
24 #define GREPROTO_MAX 2
25 #define GRE_IP_PROTO_MAX 2
28 int (*handler)(struct sk_buff *skb);
29 void (*err_handler)(struct sk_buff *skb, u32 info);
32 int gre_add_protocol(const struct gre_protocol *proto, u8 version);
33 int gre_del_protocol(const struct gre_protocol *proto, u8 version);
35 struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
37 int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
38 bool *csum_err, __be16 proto, int nhs);
40 bool is_gretap_dev(const struct net_device *dev);
41 bool is_ip6gretap_dev(const struct net_device *dev);
43 static inline int gre_calc_hlen(__be16 o_flags)
47 if (o_flags & TUNNEL_CSUM)
49 if (o_flags & TUNNEL_KEY)
51 if (o_flags & TUNNEL_SEQ)
56 static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
61 tflags |= TUNNEL_CSUM;
62 if (flags & GRE_ROUTING)
63 tflags |= TUNNEL_ROUTING;
68 if (flags & GRE_STRICT)
69 tflags |= TUNNEL_STRICT;
72 if (flags & GRE_VERSION)
73 tflags |= TUNNEL_VERSION;
78 static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
82 if (tflags & TUNNEL_CSUM)
84 if (tflags & TUNNEL_ROUTING)
86 if (tflags & TUNNEL_KEY)
88 if (tflags & TUNNEL_SEQ)
90 if (tflags & TUNNEL_STRICT)
92 if (tflags & TUNNEL_REC)
94 if (tflags & TUNNEL_VERSION)
100 static inline __sum16 gre_checksum(struct sk_buff *skb)
104 if (skb->ip_summed == CHECKSUM_PARTIAL)
105 csum = lco_csum(skb);
107 csum = skb_checksum(skb, 0, skb->len, 0);
108 return csum_fold(csum);
111 static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
112 __be16 flags, __be16 proto,
113 __be32 key, __be32 seq)
115 struct gre_base_hdr *greh;
117 skb_push(skb, hdr_len);
119 skb_set_inner_protocol(skb, proto);
120 skb_reset_transport_header(skb);
121 greh = (struct gre_base_hdr *)skb->data;
122 greh->flags = gre_tnl_flags_to_gre_flags(flags);
123 greh->protocol = proto;
125 if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
126 __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
128 if (flags & TUNNEL_SEQ) {
132 if (flags & TUNNEL_KEY) {
136 if (flags & TUNNEL_CSUM &&
137 !(skb_shinfo(skb)->gso_type &
138 (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
140 *(__sum16 *)ptr = gre_checksum(skb);