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-rw-r--r--include/net/gre.h154
1 files changed, 154 insertions, 0 deletions
diff --git a/include/net/gre.h b/include/net/gre.h
new file mode 100644
index 000000000..b60f212c1
--- /dev/null
+++ b/include/net/gre.h
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_GRE_H
+#define __LINUX_GRE_H
+
+#include <linux/skbuff.h>
+#include <net/ip_tunnels.h>
+
+struct gre_base_hdr {
+ __be16 flags;
+ __be16 protocol;
+} __packed;
+
+struct gre_full_hdr {
+ struct gre_base_hdr fixed_header;
+ __be16 csum;
+ __be16 reserved1;
+ __be32 key;
+ __be32 seq;
+} __packed;
+#define GRE_HEADER_SECTION 4
+
+#define GREPROTO_CISCO 0
+#define GREPROTO_PPTP 1
+#define GREPROTO_MAX 2
+#define GRE_IP_PROTO_MAX 2
+
+struct gre_protocol {
+ int (*handler)(struct sk_buff *skb);
+ void (*err_handler)(struct sk_buff *skb, u32 info);
+};
+
+int gre_add_protocol(const struct gre_protocol *proto, u8 version);
+int gre_del_protocol(const struct gre_protocol *proto, u8 version);
+
+struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
+ u8 name_assign_type);
+int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
+ bool *csum_err, __be16 proto, int nhs);
+
+static inline bool netif_is_gretap(const struct net_device *dev)
+{
+ return dev->rtnl_link_ops &&
+ !strcmp(dev->rtnl_link_ops->kind, "gretap");
+}
+
+static inline bool netif_is_ip6gretap(const struct net_device *dev)
+{
+ return dev->rtnl_link_ops &&
+ !strcmp(dev->rtnl_link_ops->kind, "ip6gretap");
+}
+
+static inline int gre_calc_hlen(__be16 o_flags)
+{
+ int addend = 4;
+
+ if (o_flags & TUNNEL_CSUM)
+ addend += 4;
+ if (o_flags & TUNNEL_KEY)
+ addend += 4;
+ if (o_flags & TUNNEL_SEQ)
+ addend += 4;
+ return addend;
+}
+
+static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
+{
+ __be16 tflags = 0;
+
+ if (flags & GRE_CSUM)
+ tflags |= TUNNEL_CSUM;
+ if (flags & GRE_ROUTING)
+ tflags |= TUNNEL_ROUTING;
+ if (flags & GRE_KEY)
+ tflags |= TUNNEL_KEY;
+ if (flags & GRE_SEQ)
+ tflags |= TUNNEL_SEQ;
+ if (flags & GRE_STRICT)
+ tflags |= TUNNEL_STRICT;
+ if (flags & GRE_REC)
+ tflags |= TUNNEL_REC;
+ if (flags & GRE_VERSION)
+ tflags |= TUNNEL_VERSION;
+
+ return tflags;
+}
+
+static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
+{
+ __be16 flags = 0;
+
+ if (tflags & TUNNEL_CSUM)
+ flags |= GRE_CSUM;
+ if (tflags & TUNNEL_ROUTING)
+ flags |= GRE_ROUTING;
+ if (tflags & TUNNEL_KEY)
+ flags |= GRE_KEY;
+ if (tflags & TUNNEL_SEQ)
+ flags |= GRE_SEQ;
+ if (tflags & TUNNEL_STRICT)
+ flags |= GRE_STRICT;
+ if (tflags & TUNNEL_REC)
+ flags |= GRE_REC;
+ if (tflags & TUNNEL_VERSION)
+ flags |= GRE_VERSION;
+
+ return flags;
+}
+
+static inline __sum16 gre_checksum(struct sk_buff *skb)
+{
+ __wsum csum;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL)
+ csum = lco_csum(skb);
+ else
+ csum = skb_checksum(skb, 0, skb->len, 0);
+ return csum_fold(csum);
+}
+
+static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
+ __be16 flags, __be16 proto,
+ __be32 key, __be32 seq)
+{
+ struct gre_base_hdr *greh;
+
+ skb_push(skb, hdr_len);
+
+ skb_set_inner_protocol(skb, proto);
+ skb_reset_transport_header(skb);
+ greh = (struct gre_base_hdr *)skb->data;
+ greh->flags = gre_tnl_flags_to_gre_flags(flags);
+ greh->protocol = proto;
+
+ if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
+ __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
+
+ if (flags & TUNNEL_SEQ) {
+ *ptr = seq;
+ ptr--;
+ }
+ if (flags & TUNNEL_KEY) {
+ *ptr = key;
+ ptr--;
+ }
+ if (flags & TUNNEL_CSUM &&
+ !(skb_shinfo(skb)->gso_type &
+ (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
+ *ptr = 0;
+ *(__sum16 *)ptr = gre_checksum(skb);
+ }
+ }
+}
+
+#endif