kernel: 5.4: import wireguard backport

Rather than using the clunky, old, slower wireguard-linux-compat out of
tree module, this commit does a patch-by-patch backport of upstream's
wireguard to 5.4. This specific backport is in widespread use, being
part of SUSE's enterprise kernel, Oracle's enterprise kernel, Google's
Android kernel, Gentoo's distro kernel, and probably more I've forgotten
about. It's definately the "more proper" way of adding wireguard to a
kernel than the ugly compat.h hell of the wireguard-linux-compat repo.
And most importantly for OpenWRT, it allows using the same module
configuration code for 5.10 as for 5.4, with no need for bifurcation.

These patches are from the backport tree which is maintained in the
open here: https://git.zx2c4.com/wireguard-linux/log/?h=backport-5.4.y
I'll be sending PRs to update this as needed.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0114-netlink-consistently-use-NLA_POLICY_MIN_LEN.patch b/target/linux/generic/backport-5.4/080-wireguard-0114-netlink-consistently-use-NLA_POLICY_MIN_LEN.patch
new file mode 100644
index 0000000000..a859e7c72b
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0114-netlink-consistently-use-NLA_POLICY_MIN_LEN.patch
@@ -0,0 +1,39 @@
+From 2c778b2cd59a12f0dcba236e6441a318d1c6486c Mon Sep 17 00:00:00 2001
+From: Johannes Berg <johannes.berg@intel.com>
+Date: Tue, 18 Aug 2020 10:17:32 +0200
+Subject: [PATCH 114/124] netlink: consistently use NLA_POLICY_MIN_LEN()
+
+commit bc0435855041d7fff0b83dd992fc4be34aa11afb upstream.
+
+Change places that open-code NLA_POLICY_MIN_LEN() to
+use the macro instead, giving us flexibility in how we
+handle the details of the macro.
+
+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+[Jason: only picked the drivers/net/wireguard/* part]
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ drivers/net/wireguard/netlink.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/wireguard/netlink.c
++++ b/drivers/net/wireguard/netlink.c
+@@ -34,7 +34,7 @@ static const struct nla_policy peer_poli
+ 	[WGPEER_A_PUBLIC_KEY]				= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
+ 	[WGPEER_A_PRESHARED_KEY]			= NLA_POLICY_EXACT_LEN(NOISE_SYMMETRIC_KEY_LEN),
+ 	[WGPEER_A_FLAGS]				= { .type = NLA_U32 },
+-	[WGPEER_A_ENDPOINT]				= { .type = NLA_MIN_LEN, .len = sizeof(struct sockaddr) },
++	[WGPEER_A_ENDPOINT]				= NLA_POLICY_MIN_LEN(sizeof(struct sockaddr)),
+ 	[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]	= { .type = NLA_U16 },
+ 	[WGPEER_A_LAST_HANDSHAKE_TIME]			= NLA_POLICY_EXACT_LEN(sizeof(struct __kernel_timespec)),
+ 	[WGPEER_A_RX_BYTES]				= { .type = NLA_U64 },
+@@ -45,7 +45,7 @@ static const struct nla_policy peer_poli
+ 
+ static const struct nla_policy allowedip_policy[WGALLOWEDIP_A_MAX + 1] = {
+ 	[WGALLOWEDIP_A_FAMILY]		= { .type = NLA_U16 },
+-	[WGALLOWEDIP_A_IPADDR]		= { .type = NLA_MIN_LEN, .len = sizeof(struct in_addr) },
++	[WGALLOWEDIP_A_IPADDR]		= NLA_POLICY_MIN_LEN(sizeof(struct in_addr)),
+ 	[WGALLOWEDIP_A_CIDR_MASK]	= { .type = NLA_U8 }
+ };
+