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 netif_is_gretap(const struct net_device * dev)40 static 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 netif_is_ip6gretap(const struct net_device * dev)46 static 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 gre_calc_hlen(const unsigned long * o_flags)52 static 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 gre_flags_to_tnl_flags(unsigned long * dst,__be16 flags)65 static 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 gre_tnl_flags_to_gre_flags(const unsigned long * tflags)80 static 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 gre_build_header(struct sk_buff * skb,int hdr_len,const unsigned long * flags,__be16 proto,__be32 key,__be32 seq)102 static 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 148