148 lines
3.8 KiB
C
148 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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 bool netif_is_gretap(const struct net_device *dev)
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{
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return dev->rtnl_link_ops &&
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!strcmp(dev->rtnl_link_ops->kind, "gretap");
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}
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static inline bool netif_is_ip6gretap(const struct net_device *dev)
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{
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return dev->rtnl_link_ops &&
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!strcmp(dev->rtnl_link_ops->kind, "ip6gretap");
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}
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static inline int gre_calc_hlen(const unsigned long *o_flags)
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{
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int addend = 4;
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if (test_bit(IP_TUNNEL_CSUM_BIT, o_flags))
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addend += 4;
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if (test_bit(IP_TUNNEL_KEY_BIT, o_flags))
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addend += 4;
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if (test_bit(IP_TUNNEL_SEQ_BIT, o_flags))
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addend += 4;
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return addend;
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}
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static inline void gre_flags_to_tnl_flags(unsigned long *dst, __be16 flags)
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{
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IP_TUNNEL_DECLARE_FLAGS(res) = { };
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__assign_bit(IP_TUNNEL_CSUM_BIT, res, flags & GRE_CSUM);
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__assign_bit(IP_TUNNEL_ROUTING_BIT, res, flags & GRE_ROUTING);
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__assign_bit(IP_TUNNEL_KEY_BIT, res, flags & GRE_KEY);
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__assign_bit(IP_TUNNEL_SEQ_BIT, res, flags & GRE_SEQ);
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__assign_bit(IP_TUNNEL_STRICT_BIT, res, flags & GRE_STRICT);
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__assign_bit(IP_TUNNEL_REC_BIT, res, flags & GRE_REC);
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__assign_bit(IP_TUNNEL_VERSION_BIT, res, flags & GRE_VERSION);
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ip_tunnel_flags_copy(dst, res);
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}
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static inline __be16 gre_tnl_flags_to_gre_flags(const unsigned long *tflags)
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{
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__be16 flags = 0;
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if (test_bit(IP_TUNNEL_CSUM_BIT, tflags))
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flags |= GRE_CSUM;
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if (test_bit(IP_TUNNEL_ROUTING_BIT, tflags))
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flags |= GRE_ROUTING;
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if (test_bit(IP_TUNNEL_KEY_BIT, tflags))
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flags |= GRE_KEY;
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if (test_bit(IP_TUNNEL_SEQ_BIT, tflags))
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flags |= GRE_SEQ;
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if (test_bit(IP_TUNNEL_STRICT_BIT, tflags))
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flags |= GRE_STRICT;
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if (test_bit(IP_TUNNEL_REC_BIT, tflags))
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flags |= GRE_REC;
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if (test_bit(IP_TUNNEL_VERSION_BIT, tflags))
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flags |= GRE_VERSION;
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return flags;
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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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const unsigned long *flags, __be16 proto,
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__be32 key, __be32 seq)
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{
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IP_TUNNEL_DECLARE_FLAGS(cond) = { };
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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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__set_bit(IP_TUNNEL_KEY_BIT, cond);
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__set_bit(IP_TUNNEL_CSUM_BIT, cond);
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__set_bit(IP_TUNNEL_SEQ_BIT, cond);
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if (ip_tunnel_flags_intersect(flags, cond)) {
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__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
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if (test_bit(IP_TUNNEL_SEQ_BIT, flags)) {
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*ptr = seq;
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ptr--;
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}
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if (test_bit(IP_TUNNEL_KEY_BIT, flags)) {
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*ptr = key;
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ptr--;
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}
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if (test_bit(IP_TUNNEL_CSUM_BIT, flags) &&
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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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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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*(__sum16 *)ptr = csum_fold(lco_csum(skb));
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} else {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = sizeof(*greh);
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}
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}
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}
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}
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#endif
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