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, 52 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0120-wireguard-selftests-test-multiple-parallel-streams.patch b/target/linux/generic/backport-5.4/080-wireguard-0120-wireguard-selftests-test-multiple-parallel-streams.patch
new file mode 100644
index 0000000000..269f30f885
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0120-wireguard-selftests-test-multiple-parallel-streams.patch
@@ -0,0 +1,52 @@
+From 5c4e6ed057bcaa6ece0386344ba787d88c8307d2 Mon Sep 17 00:00:00 2001
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Mon, 22 Feb 2021 17:25:45 +0100
+Subject: [PATCH 120/124] wireguard: selftests: test multiple parallel streams
+
+commit d5a49aa6c3e264a93a7d08485d66e346be0969dd upstream.
+
+In order to test ndo_start_xmit being called in parallel, explicitly add
+separate tests, which should all run on different cores. This should
+help tease out bugs associated with queueing up packets from different
+cores in parallel. Currently, it hasn't found those types of bugs, but
+given future planned work, this is a useful regression to avoid.
+
+Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ tools/testing/selftests/wireguard/netns.sh | 15 ++++++++++++++-
+ 1 file changed, 14 insertions(+), 1 deletion(-)
+
+--- a/tools/testing/selftests/wireguard/netns.sh
++++ b/tools/testing/selftests/wireguard/netns.sh
+@@ -39,7 +39,7 @@ ip0() { pretty 0 "ip $*"; ip -n $netns0
+ ip1() { pretty 1 "ip $*"; ip -n $netns1 "$@"; }
+ ip2() { pretty 2 "ip $*"; ip -n $netns2 "$@"; }
+ sleep() { read -t "$1" -N 1 || true; }
+-waitiperf() { pretty "${1//*-}" "wait for iperf:5201 pid $2"; while [[ $(ss -N "$1" -tlpH 'sport = 5201') != *\"iperf3\",pid=$2,fd=* ]]; do sleep 0.1; done; }
++waitiperf() { pretty "${1//*-}" "wait for iperf:${3:-5201} pid $2"; while [[ $(ss -N "$1" -tlpH "sport = ${3:-5201}") != *\"iperf3\",pid=$2,fd=* ]]; do sleep 0.1; done; }
+ waitncatudp() { pretty "${1//*-}" "wait for udp:1111 pid $2"; while [[ $(ss -N "$1" -ulpH 'sport = 1111') != *\"ncat\",pid=$2,fd=* ]]; do sleep 0.1; done; }
+ waitiface() { pretty "${1//*-}" "wait for $2 to come up"; ip netns exec "$1" bash -c "while [[ \$(< \"/sys/class/net/$2/operstate\") != up ]]; do read -t .1 -N 0 || true; done;"; }
+ 
+@@ -141,6 +141,19 @@ tests() {
+ 	n2 iperf3 -s -1 -B fd00::2 &
+ 	waitiperf $netns2 $!
+ 	n1 iperf3 -Z -t 3 -b 0 -u -c fd00::2
++
++	# TCP over IPv4, in parallel
++	for max in 4 5 50; do
++		local pids=( )
++		for ((i=0; i < max; ++i)) do
++			n2 iperf3 -p $(( 5200 + i )) -s -1 -B 192.168.241.2 &
++			pids+=( $! ); waitiperf $netns2 $! $(( 5200 + i ))
++		done
++		for ((i=0; i < max; ++i)) do
++			n1 iperf3 -Z -t 3 -p $(( 5200 + i )) -c 192.168.241.2 &
++		done
++		wait "${pids[@]}"
++	done
+ }
+ 
+ [[ $(ip1 link show dev wg0) =~ mtu\ ([0-9]+) ]] && orig_mtu="${BASH_REMATCH[1]}"