| 1 |
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| 2 | #ifndef __LINUX_GRE_H
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| 3 | #define __LINUX_GRE_H
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| 4 |
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| 5 | #include <linux/skbuff.h>
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| 6 | #include <net/ip_tunnels.h>
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| 7 |
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| 8 | struct gre_base_hdr {
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| 9 | __be16 flags;
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| 10 | __be16 protocol;
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| 11 | } __packed;
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| 12 |
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| 13 | struct gre_full_hdr {
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| 14 | struct gre_base_hdr fixed_header;
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| 15 | __be16 csum;
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| 16 | __be16 reserved1;
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| 17 | __be32 key;
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| 18 | __be32 seq;
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| 19 | } __packed;
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| 20 | #define GRE_HEADER_SECTION 4
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| 21 |
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| 22 | #define GREPROTO_CISCO 0
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| 23 | #define GREPROTO_PPTP 1
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| 24 | #define GREPROTO_MAX 2
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| 25 | #define GRE_IP_PROTO_MAX 2
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| 26 |
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| 27 | struct gre_protocol {
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| 28 | int (*handler)(struct sk_buff *skb);
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| 29 | void (*err_handler)(struct sk_buff *skb, u32 info);
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| 30 | };
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| 31 |
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| 32 | int gre_add_protocol(const struct gre_protocol *proto, u8 version);
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| 33 | int gre_del_protocol(const struct gre_protocol *proto, u8 version);
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| 34 |
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| 35 | int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
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| 36 | bool *csum_err, __be16 proto, int nhs);
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| 37 |
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| 38 | static inline bool netif_is_gretap(const struct net_device *dev)
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| 39 | {
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| 40 | return dev->rtnl_link_ops &&
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| 41 | !strcmp(dev->rtnl_link_ops->kind, "gretap");
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| 42 | }
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| 43 |
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| 44 | static inline bool netif_is_ip6gretap(const struct net_device *dev)
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| 45 | {
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| 46 | return dev->rtnl_link_ops &&
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| 47 | !strcmp(dev->rtnl_link_ops->kind, "ip6gretap");
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| 48 | }
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| 49 |
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| 50 | static inline int gre_calc_hlen(const unsigned long *o_flags)
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| 51 | {
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| 52 | int addend = 4;
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| 53 |
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| 54 | if (test_bit(IP_TUNNEL_CSUM_BIT, o_flags))
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| 55 | addend += 4;
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| 56 | if (test_bit(IP_TUNNEL_KEY_BIT, o_flags))
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| 57 | addend += 4;
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| 58 | if (test_bit(IP_TUNNEL_SEQ_BIT, o_flags))
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| 59 | addend += 4;
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| 60 | return addend;
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| 61 | }
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| 62 |
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| 63 | static inline void gre_flags_to_tnl_flags(unsigned long *dst, __be16 flags)
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| 64 | {
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| 65 | IP_TUNNEL_DECLARE_FLAGS(res) = { };
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| 66 |
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| 67 | __assign_bit(IP_TUNNEL_CSUM_BIT, res, flags & GRE_CSUM);
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| 68 | __assign_bit(IP_TUNNEL_ROUTING_BIT, res, flags & GRE_ROUTING);
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| 69 | __assign_bit(IP_TUNNEL_KEY_BIT, res, flags & GRE_KEY);
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| 70 | __assign_bit(IP_TUNNEL_SEQ_BIT, res, flags & GRE_SEQ);
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| 71 | __assign_bit(IP_TUNNEL_STRICT_BIT, res, flags & GRE_STRICT);
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| 72 | __assign_bit(IP_TUNNEL_REC_BIT, res, flags & GRE_REC);
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| 73 | __assign_bit(IP_TUNNEL_VERSION_BIT, res, flags & GRE_VERSION);
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| 74 |
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| 75 | ip_tunnel_flags_copy(dst, res);
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| 76 | }
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| 77 |
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| 78 | static inline __be16 gre_tnl_flags_to_gre_flags(const unsigned long *tflags)
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| 79 | {
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| 80 | __be16 flags = 0;
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| 81 |
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| 82 | if (test_bit(IP_TUNNEL_CSUM_BIT, tflags))
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| 83 | flags |= GRE_CSUM;
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| 84 | if (test_bit(IP_TUNNEL_ROUTING_BIT, tflags))
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| 85 | flags |= GRE_ROUTING;
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| 86 | if (test_bit(IP_TUNNEL_KEY_BIT, tflags))
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| 87 | flags |= GRE_KEY;
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| 88 | if (test_bit(IP_TUNNEL_SEQ_BIT, tflags))
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| 89 | flags |= GRE_SEQ;
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| 90 | if (test_bit(IP_TUNNEL_STRICT_BIT, tflags))
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| 91 | flags |= GRE_STRICT;
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| 92 | if (test_bit(IP_TUNNEL_REC_BIT, tflags))
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| 93 | flags |= GRE_REC;
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| 94 | if (test_bit(IP_TUNNEL_VERSION_BIT, tflags))
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| 95 | flags |= GRE_VERSION;
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| 96 |
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| 97 | return flags;
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| 98 | }
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| 99 |
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| 100 | static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
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| 101 | const unsigned long *flags, __be16 proto,
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| 102 | __be32 key, __be32 seq)
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| 103 | {
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| 104 | IP_TUNNEL_DECLARE_FLAGS(cond) = { };
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| 105 | struct gre_base_hdr *greh;
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| 106 |
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| 107 | skb_push(skb, hdr_len);
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| 108 |
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| 109 | skb_set_inner_protocol(skb, proto);
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| 110 | skb_reset_transport_header(skb);
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| 111 | greh = (struct gre_base_hdr *)skb->data;
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| 112 | greh->flags = gre_tnl_flags_to_gre_flags(flags);
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| 113 | greh->protocol = proto;
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| 114 |
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| 115 | __set_bit(IP_TUNNEL_KEY_BIT, cond);
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| 116 | __set_bit(IP_TUNNEL_CSUM_BIT, cond);
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| 117 | __set_bit(IP_TUNNEL_SEQ_BIT, cond);
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| 118 |
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| 119 | if (ip_tunnel_flags_intersect(flags, cond)) {
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| 120 | __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
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| 121 |
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| 122 | if (test_bit(IP_TUNNEL_SEQ_BIT, flags)) {
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| 123 | *ptr = seq;
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| 124 | ptr--;
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| 125 | }
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| 126 | if (test_bit(IP_TUNNEL_KEY_BIT, flags)) {
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| 127 | *ptr = key;
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| 128 | ptr--;
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| 129 | }
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| 130 | if (test_bit(IP_TUNNEL_CSUM_BIT, flags) &&
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| 131 | !(skb_shinfo(skb)->gso_type &
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| 132 | (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
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| 133 | *ptr = 0;
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| 134 | if (skb->ip_summed == CHECKSUM_PARTIAL) {
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| 135 | *(__sum16 *)ptr = csum_fold(lco_csum(skb));
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| 136 | } else {
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| 137 | skb->ip_summed = CHECKSUM_PARTIAL;
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| 138 | skb->csum_start = skb_transport_header(skb) - skb->head;
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| 139 | skb->csum_offset = sizeof(*greh);
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| 140 | }
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| 141 | }
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| 142 | }
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| 143 | }
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| 144 |
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| 145 | #endif
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