kernel: migrate wireguard into the kernel tree

On Linux 5.4, build WireGuard from backports. Linux 5.10 contains
wireguard in-tree.

Add in-kernel crypto libraries required by WireGuard along with
arch-specific optimizations.

Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
(cherry picked from commit 06351f1bd0)
(cherry picked from commit 464451d9ab)

package/kernel/linux/modules/crypto.mk

@@ -11,6 +11,8 @@ CRYPTO_MODULES = \
 	ALGAPI2=crypto_algapi \
 	BLKCIPHER2=crypto_blkcipher
 
+CRYPTO_TARGET = $(BOARD)/$(if $(SUBTARGET),$(SUBTARGET),generic)
+
 crypto_confvar=CONFIG_CRYPTO_$(word 1,$(subst =,$(space),$(1)))
 crypto_file=$(LINUX_DIR)/crypto/$(word 2,$(subst =,$(space),$(1))).ko
 crypto_name=$(if $(findstring y,$($(call crypto_confvar,$(1)))),,$(word 2,$(subst =,$(space),$(1))))
@@ -422,7 +424,6 @@ $(eval $(call KernelPackage,crypto-hw-talitos))
 define KernelPackage/crypto-kpp
   TITLE:=Key-agreement Protocol Primitives
   KCONFIG:=CONFIG_CRYPTO_KPP
-  HIDDEN:=1
   FILES:=$(LINUX_DIR)/crypto/kpp.ko
   AUTOLOAD:=$(call AutoLoad,09,kpp)
   $(call AddDepends/crypto)
@@ -431,6 +432,158 @@ endef
 $(eval $(call KernelPackage,crypto-kpp))
 
 
+define KernelPackage/crypto-lib-blake2s
+  TITLE:=BLAKE2s hash function library
+  KCONFIG:=CONFIG_CRYPTO_LIB_BLAKE2S
+  HIDDEN:=1
+  FILES:= \
+	$(LINUX_DIR)/lib/crypto/libblake2s.ko \
+	$(LINUX_DIR)/lib/crypto/libblake2s-generic.ko
+  $(call AddDepends/crypto,+PACKAGE_kmod-crypto-hash:kmod-crypto-hash)
+endef
+
+define KernelPackage/crypto-lib-blake2s/config
+  imply PACKAGE_kmod-crypto-hash
+endef
+
+define KernelPackage/crypto-lib-blake2s/x86/64
+  KCONFIG+=CONFIG_CRYPTO_BLAKE2S_X86
+  FILES+=$(LINUX_DIR)/arch/x86/crypto/blake2s-x86_64.ko
+endef
+
+$(eval $(call KernelPackage,crypto-lib-blake2s))
+
+
+define KernelPackage/crypto-lib-chacha20
+  TITLE:=ChaCha library interface
+  KCONFIG:=CONFIG_CRYPTO_LIB_CHACHA
+  HIDDEN:=1
+  FILES:=$(LINUX_DIR)/lib/crypto/libchacha.ko
+  $(call AddDepends/crypto)
+endef
+
+define KernelPackage/crypto-lib-chacha20/x86_64
+  KCONFIG+=CONFIG_CRYPTO_CHACHA20_X86_64
+  FILES+=$(LINUX_DIR)/arch/x86/crypto/chacha-x86_64.ko
+endef
+
+# Note that a non-neon fallback implementation is available on arm32 when
+# NEON is not supported, hence all arm targets can utilize lib-chacha20/arm
+define KernelPackage/crypto-lib-chacha20/arm
+  KCONFIG+=CONFIG_CRYPTO_CHACHA20_NEON
+  FILES:=$(LINUX_DIR)/arch/arm/crypto/chacha-neon.ko
+endef
+
+define KernelPackage/crypto-lib-chacha20/aarch64
+  KCONFIG+=CONFIG_CRYPTO_CHACHA20_NEON
+  FILES+=$(LINUX_DIR)/arch/arm64/crypto/chacha-neon.ko
+endef
+
+define KernelPackage/crypto-lib-chacha20/mips32r2
+  KCONFIG+=CONFIG_CRYPTO_CHACHA_MIPS
+  FILES:=$(LINUX_DIR)/arch/mips/crypto/chacha-mips.ko
+endef
+
+ifeq ($(CONFIG_CPU_MIPS32_R2),y)
+  KernelPackage/crypto-lib-chacha20/$(ARCH)=\
+	  $(KernelPackage/crypto-lib-chacha20/mips32r2)
+endif
+
+ifdef KernelPackage/crypto-lib-chacha20/$(ARCH)
+  KernelPackage/crypto-lib-chacha20/$(CRYPTO_TARGET)=\
+	  $(KernelPackage/crypto-lib-chacha20/$(ARCH))
+endif
+
+$(eval $(call KernelPackage,crypto-lib-chacha20))
+
+
+define KernelPackage/crypto-lib-chacha20poly1305
+  TITLE:=ChaCha20-Poly1305 AEAD support (8-byte nonce library version)
+  KCONFIG:=CONFIG_CRYPTO_LIB_CHACHA20POLY1305
+  HIDDEN:=1
+  FILES:=$(LINUX_DIR)/lib/crypto/libchacha20poly1305.ko
+  $(call AddDepends/crypto, +kmod-crypto-lib-chacha20 +kmod-crypto-lib-poly1305)
+endef
+
+$(eval $(call KernelPackage,crypto-lib-chacha20poly1305))
+
+
+define KernelPackage/crypto-lib-curve25519
+  TITLE:=Curve25519 scalar multiplication library
+  KCONFIG:=CONFIG_CRYPTO_LIB_CURVE25519
+  HIDDEN:=1
+  FILES:= \
+	$(LINUX_DIR)/lib/crypto/libcurve25519.ko \
+	$(LINUX_DIR)/lib/crypto/libcurve25519-generic.ko
+  $(call AddDepends/crypto,+PACKAGE_kmod-crypto-kpp:kmod-crypto-kpp)
+endef
+
+define KernelPackage/crypto-lib-curve25519/config
+  imply PACKAGE_kmod-crypto-kpp
+endef
+
+define KernelPackage/crypto-lib-curve25519/x86/64
+  KCONFIG+=CONFIG_CRYPTO_CURVE25519_X86
+  FILES+=$(LINUX_DIR)/arch/x86/crypto/curve25519-x86_64.ko
+endef
+
+define KernelPackage/crypto-lib-curve25519/arm-neon
+  KCONFIG+=CONFIG_CRYPTO_CURVE25519_NEON
+  FILES+=$(LINUX_DIR)/arch/arm/crypto/curve25519-neon.ko
+endef
+
+ifeq ($(ARCH)-$(CONFIG_KERNEL_MODE_NEON),arm-y)
+  KernelPackage/crypto-lib-curve25519/$(CRYPTO_TARGET)=\
+	  $(KernelPackage/crypto-lib-curve25519/arm-neon)
+endif
+
+$(eval $(call KernelPackage,crypto-lib-curve25519))
+
+
+define KernelPackage/crypto-lib-poly1305
+  TITLE:=Poly1305 library interface
+  KCONFIG:=CONFIG_CRYPTO_LIB_POLY1305
+  HIDDEN:=1
+  FILES:=$(LINUX_DIR)/lib/crypto/libpoly1305.ko
+  $(call AddDepends/crypto,+PACKAGE_kmod-crypto-hash:kmod-crypto-hash)
+endef
+
+define KernelPackage/crypto-lib-poly1305/config
+  imply PACKAGE_kmod-crypto-hash
+endef
+
+define KernelPackage/crypto-lib-poly1305/x86_64
+  KCONFIG+=CONFIG_CRYPTO_POLY1305_X86_64
+  FILES+=$(LINUX_DIR)/arch/x86/crypto/poly1305-x86_64.ko
+endef
+
+define KernelPackage/crypto-lib-poly1305/arm
+  KCONFIG+=CONFIG_CRYPTO_POLY1305_ARM
+  FILES:=$(LINUX_DIR)/arch/arm/crypto/poly1305-arm.ko
+endef
+
+define KernelPackage/crypto-lib-poly1305/aarch64
+  KCONFIG+=CONFIG_CRYPTO_POLY1305_NEON
+  FILES:=$(LINUX_DIR)/arch/arm64/crypto/poly1305-neon.ko
+endef
+
+define KernelPackage/crypto-lib-poly1305/mips
+  KCONFIG+=CONFIG_CRYPTO_POLY1305_MIPS
+  FILES:=$(LINUX_DIR)/arch/mips/crypto/poly1305-mips.ko
+endef
+
+KernelPackage/crypto-lib-poly1305/mipsel=$(KernelPackage/crypto-lib-poly1305/mips)
+KernelPackage/crypto-lib-poly1305/mips64=$(KernelPackage/crypto-lib-poly1305/mips)
+KernelPackage/crypto-lib-poly1305/mips64el=$(KernelPackage/crypto-lib-poly1305/mips)
+
+ifdef KernelPackage/crypto-lib-poly1305/$(ARCH)
+  KernelPackage/crypto-lib-poly1305/$(CRYPTO_TARGET)=\
+	  $(KernelPackage/crypto-lib-poly1305/$(ARCH))
+endif
+
+$(eval $(call KernelPackage,crypto-lib-poly1305))
+
+
 define KernelPackage/crypto-manager
   TITLE:=CryptoAPI algorithm manager
   DEPENDS:=+kmod-crypto-aead +kmod-crypto-hash +kmod-crypto-pcompress

package/kernel/linux/modules/netsupport.mk

@@ -1250,3 +1250,33 @@ define KernelPackage/netlink-diag/description
 endef
 
 $(eval $(call KernelPackage,netlink-diag))
+
+
+define KernelPackage/wireguard
+  SECTION:=kernel
+  CATEGORY:=Kernel modules
+  SUBMENU:=Network Support
+  TITLE:=WireGuard kernel module
+  DEPENDS:= \
+	  +kmod-crypto-lib-blake2s \
+	  +kmod-crypto-lib-chacha20poly1305 \
+	  +kmod-crypto-lib-curve25519 \
+	  +kmod-udptunnel4 \
+	  +IPV6:kmod-udptunnel6
+  KCONFIG:= \
+	  CONFIG_WIREGUARD \
+	  CONFIG_WIREGUARD_DEBUG=n
+  FILES:=$(LINUX_DIR)/drivers/net/wireguard/wireguard.ko
+  AUTOLOAD:=$(call AutoProbe,wireguard)
+endef
+
+define KernelPackage/wireguard/description
+  WireGuard is a novel VPN that runs inside the Linux Kernel and utilizes
+  state-of-the-art cryptography. It aims to be faster, simpler, leaner, and
+  more useful than IPSec, while avoiding the massive headache. It intends to
+  be considerably more performant than OpenVPN.  WireGuard is designed as a
+  general purpose VPN for running on embedded interfaces and super computers
+  alike, fit for many different circumstances. It uses UDP.
+endef
+
+$(eval $(call KernelPackage,wireguard))