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, 33 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0107-wireguard-noise-do-not-assign-initiation-time-in-if-.patch b/target/linux/generic/backport-5.4/080-wireguard-0107-wireguard-noise-do-not-assign-initiation-time-in-if-.patch
new file mode 100644
index 0000000000..b549b32258
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0107-wireguard-noise-do-not-assign-initiation-time-in-if-.patch
@@ -0,0 +1,33 @@
+From adb4079f56d1f6c7d4dc827d7eba14e3436512f9 Mon Sep 17 00:00:00 2001
+From: Frank Werner-Krippendorf <mail@hb9fxq.ch>
+Date: Tue, 23 Jun 2020 03:59:44 -0600
+Subject: [PATCH 107/124] wireguard: noise: do not assign initiation time in if
+ condition
+
+commit 558b353c9c2a717509f291c066c6bd8f5f5e21be upstream.
+
+Fixes an error condition reported by checkpatch.pl which caused by
+assigning a variable in an if condition in wg_noise_handshake_consume_
+initiation().
+
+Signed-off-by: Frank Werner-Krippendorf <mail@hb9fxq.ch>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ drivers/net/wireguard/noise.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/wireguard/noise.c
++++ b/drivers/net/wireguard/noise.c
+@@ -617,8 +617,8 @@ wg_noise_handshake_consume_initiation(st
+ 	memcpy(handshake->hash, hash, NOISE_HASH_LEN);
+ 	memcpy(handshake->chaining_key, chaining_key, NOISE_HASH_LEN);
+ 	handshake->remote_index = src->sender_index;
+-	if ((s64)(handshake->last_initiation_consumption -
+-	    (initiation_consumption = ktime_get_coarse_boottime_ns())) < 0)
++	initiation_consumption = ktime_get_coarse_boottime_ns();
++	if ((s64)(handshake->last_initiation_consumption - initiation_consumption) < 0)
+ 		handshake->last_initiation_consumption = initiation_consumption;
+ 	handshake->state = HANDSHAKE_CONSUMED_INITIATION;
+ 	up_write(&handshake->lock);