142 lines
3.0 KiB
C
142 lines
3.0 KiB
C
#ifndef __LINUX_GRE_H
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#define __LINUX_GRE_H
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#include <linux/skbuff.h>
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#include <net/ip_tunnels.h>
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struct gre_base_hdr {
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__be16 flags;
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__be16 protocol;
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} __packed;
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struct gre_full_hdr {
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struct gre_base_hdr fixed_header;
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__be16 csum;
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__be16 reserved1;
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__be32 key;
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__be32 seq;
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} __packed;
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#define GRE_HEADER_SECTION 4
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#define GREPROTO_CISCO 0
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#define GREPROTO_PPTP 1
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#define GREPROTO_MAX 2
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#define GRE_IP_PROTO_MAX 2
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struct gre_protocol {
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int (*handler)(struct sk_buff *skb);
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void (*err_handler)(struct sk_buff *skb, u32 info);
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};
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int gre_add_protocol(const struct gre_protocol *proto, u8 version);
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int gre_del_protocol(const struct gre_protocol *proto, u8 version);
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struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
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u8 name_assign_type);
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int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
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bool *csum_err, __be16 proto, int nhs);
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static inline int gre_calc_hlen(__be16 o_flags)
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{
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int addend = 4;
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if (o_flags & TUNNEL_CSUM)
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addend += 4;
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if (o_flags & TUNNEL_KEY)
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addend += 4;
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if (o_flags & TUNNEL_SEQ)
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addend += 4;
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return addend;
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}
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static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
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{
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__be16 tflags = 0;
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if (flags & GRE_CSUM)
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tflags |= TUNNEL_CSUM;
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if (flags & GRE_ROUTING)
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tflags |= TUNNEL_ROUTING;
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if (flags & GRE_KEY)
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tflags |= TUNNEL_KEY;
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if (flags & GRE_SEQ)
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tflags |= TUNNEL_SEQ;
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if (flags & GRE_STRICT)
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tflags |= TUNNEL_STRICT;
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if (flags & GRE_REC)
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tflags |= TUNNEL_REC;
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if (flags & GRE_VERSION)
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tflags |= TUNNEL_VERSION;
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return tflags;
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}
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static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
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{
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__be16 flags = 0;
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if (tflags & TUNNEL_CSUM)
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flags |= GRE_CSUM;
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if (tflags & TUNNEL_ROUTING)
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flags |= GRE_ROUTING;
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if (tflags & TUNNEL_KEY)
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flags |= GRE_KEY;
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if (tflags & TUNNEL_SEQ)
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flags |= GRE_SEQ;
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if (tflags & TUNNEL_STRICT)
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flags |= GRE_STRICT;
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if (tflags & TUNNEL_REC)
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flags |= GRE_REC;
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if (tflags & TUNNEL_VERSION)
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flags |= GRE_VERSION;
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return flags;
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}
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static inline __sum16 gre_checksum(struct sk_buff *skb)
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{
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__wsum csum;
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if (skb->ip_summed == CHECKSUM_PARTIAL)
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csum = lco_csum(skb);
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else
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csum = skb_checksum(skb, 0, skb->len, 0);
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return csum_fold(csum);
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}
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static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
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__be16 flags, __be16 proto,
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__be32 key, __be32 seq)
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{
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struct gre_base_hdr *greh;
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skb_push(skb, hdr_len);
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skb_set_inner_protocol(skb, proto);
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skb_reset_transport_header(skb);
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greh = (struct gre_base_hdr *)skb->data;
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greh->flags = gre_tnl_flags_to_gre_flags(flags);
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greh->protocol = proto;
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if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
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__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
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if (flags & TUNNEL_SEQ) {
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*ptr = seq;
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ptr--;
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}
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if (flags & TUNNEL_KEY) {
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*ptr = key;
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ptr--;
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}
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if (flags & TUNNEL_CSUM &&
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!(skb_shinfo(skb)->gso_type &
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(SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
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*ptr = 0;
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*(__sum16 *)ptr = gre_checksum(skb);
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}
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}
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}
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#endif
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