trivial change to build on 5.14.x

bbonev · Oct 3, 2021 · 1fcf639 · 1fcf639
1 parent 2f71cbe
commit 1fcf639
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diff --git a/out-of-tree-5.14.x/Makefile b/out-of-tree-5.14.x/Makefile
@@ -0,0 +1,24 @@
+ifneq ($(KERNELRELEASE),)
+# ugly and dirty hack to avoid patching system's kernel headers
+ccflags-y += "-DGREPROTO_NONSTD_EOIP=0x80"
+ccflags-y += "-DGREPROTO_NONSTD_MAX=0x81"
+ccflags-y += "-DGREPROTO_NONSTD_BASE=0x80"
+obj-m  := eoip.o
+obj-m  += gre.o
+else
+KDIR ?= /lib/modules/`uname -r`/build
+default: eoip.c gre.c gre.h
+	@$(MAKE) -C $(KDIR) M=$$PWD
+eoip.c: ../kernel-patch/kernel-5.6.0-eoip.patch
+	@patch -p3 < $<
+gre.c gre.h: ../kernel-patch/kernel-5.6.0-eoip-gre-demux.patch
+	@if [ -f /lib/modules/`uname -r`/build/net/ipv4/gre.c ]; then echo found running kernel version of gre.c; cp /lib/modules/`uname -r`/build/net/ipv4/gre_demux.c gre_demux.c; else echo using 5.14.0 version of gre_demux.c; cp gre_demux-5.14.0.c gre_demux.c; fi
+	@if [ -f /lib/modules/`uname -r`/build/include/net/gre.h ]; then echo found running kernel version of gre.h; cp /lib/modules/`uname -r`/build/include/net/gre.h gre.h; else echo using 5.14.0 version of gre.h; cp gre-5.14.0.h gre.h; fi
+	@patch -p3 < $<
+	@cp gre_demux.c gre.c
+clean:
+	@rm -f gre_demux.c gre.c gre.h eoip.c *.orig *.rej
+	@$(MAKE) -C $(KDIR) M=$$PWD clean
+install modules_install:
+	@$(MAKE) -C $(KDIR) M=$$PWD modules_install
+endif
diff --git a/out-of-tree-5.14.x/gre-5.14.0.h b/out-of-tree-5.14.x/gre-5.14.0.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