From c3f26340e63b9f815a752af0a8bbc757b7f0cac1 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 18 Oct 2020 22:27:22 +0200
Subject: [PATCH] wg-quick: openbsd: no use for userspace support

With alignment between the kernel and userspace, along with userspace
packages, we can now rely on the kernel in the future always having
wg(4).

This also simplifies the interface selection logic, and stores the
wg-quick interface name as the description.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 src/wg-quick/openbsd.bash | 64 ++++++++++++++-------------------------
 1 file changed, 23 insertions(+), 41 deletions(-)

diff --git a/src/wg-quick/openbsd.bash b/src/wg-quick/openbsd.bash
index ffd1834..15550c8 100755
--- a/src/wg-quick/openbsd.bash
+++ b/src/wg-quick/openbsd.bash
@@ -88,42 +88,33 @@ auto_su() {
 
 
 get_real_interface() {
-	local interface diff
-	wg show interfaces >/dev/null
-	[[ -f "/var/run/wireguard/$INTERFACE.name" ]] || return 1
-	interface="$(< "/var/run/wireguard/$INTERFACE.name")"
-	if [[ $interface != wg* ]]; then
-		[[ -n $interface && -S "/var/run/wireguard/$interface.sock" ]] || return 1
-		diff=$(( $(stat -f %m "/var/run/wireguard/$interface.sock" 2>/dev/null || echo 200) - $(stat -f %m "/var/run/wireguard/$INTERFACE.name" 2>/dev/null || echo 100) ))
-		[[ $diff -ge 2 || $diff -le -2 ]] && return 1
-		echo "[+] Tun interface for $INTERFACE is $interface" >&2
-	else
-		[[ " $(wg show interfaces) " == *" $interface "* ]] || return 1
-	fi
-	REAL_INTERFACE="$interface"
-	return 0
+	local interface line
+	while IFS= read -r line; do
+		if [[ $line =~ ^([a-z]+[0-9]+):\ .+ ]]; then
+			interface="${BASH_REMATCH[1]}"
+			continue
+		fi
+		if [[ $interface == wg* && $line =~ ^\	description:\ wg-quick:\ (.+) && ${BASH_REMATCH[1]} == "$INTERFACE" ]]; then
+			REAL_INTERFACE="$interface"
+			return 0
+		fi
+	done < <(ifconfig)
+	return 1
 }
 
 add_if() {
-	local index=0 ret
 	while true; do
-		if ret="$(cmd ifconfig wg$index create 2>&1)"; then
-			mkdir -p "/var/run/wireguard/"
-			echo wg$index > /var/run/wireguard/$INTERFACE.name
-			get_real_interface
+		local -A existing_ifs="( $(wg show interfaces | sed 's/\([^ ]*\)/[\1]=1/g') )"
+		local index ret
+		for ((index=0; index <= 2147483647; ++index)); do [[ -v existing_ifs[wg$index] ]] || break; done
+		if ret="$(cmd ifconfig wg$index create description "wg-quick: $INTERFACE" 2>&1)"; then
+			REAL_INTERFACE="wg$index"
 			return 0
 		fi
-		if [[ $ret != *"ifconfig: SIOCIFCREATE: File exists"* ]]; then
-			echo "[!] Missing WireGuard kernel support ($ret). Falling back to slow userspace implementation." >&3
-			break
-		fi
-		echo "[+] wg$index in use, trying next"
-		((++index))
+		[[ $ret == *"ifconfig: SIOCIFCREATE: File exists"* ]] && continue
+		echo "$ret" >&3
+		return 1
 	done
-	export WG_TUN_NAME_FILE="/var/run/wireguard/$INTERFACE.name"
-	mkdir -p "/var/run/wireguard/"
-	cmd "${WG_QUICK_USERSPACE_IMPLEMENTATION:-wireguard-go}" tun
-	get_real_interface
 }
 
 del_routes() {
@@ -153,12 +144,7 @@ del_routes() {
 
 del_if() {
 	unset_dns
-	if [[ -n $REAL_INTERFACE && $REAL_INTERFACE != wg* ]]; then
-		cmd rm -f "/var/run/wireguard/$REAL_INTERFACE.sock"
-	else
-		cmd ifconfig $REAL_INTERFACE destroy
-	fi
-	cmd rm -f "/var/run/wireguard/$INTERFACE.name"
+	[[ -n $REAL_INTERFACE ]] && cmd ifconfig $REAL_INTERFACE destroy
 }
 
 up_if() {
@@ -438,9 +424,7 @@ cmd_up() {
 }
 
 cmd_down() {
-	if ! get_real_interface || [[ " $(wg show interfaces) " != *" $REAL_INTERFACE "* ]]; then
-		die "\`$INTERFACE' is not a WireGuard interface"
-	fi
+	get_real_interface || die "\`$INTERFACE' is not a WireGuard interface"
 	execute_hooks "${PRE_DOWN[@]}"
 	[[ $SAVE_CONFIG -eq 0 ]] || save_config
 	del_if
@@ -449,9 +433,7 @@ cmd_down() {
 }
 
 cmd_save() {
-	if ! get_real_interface || [[ " $(wg show interfaces) " != *" $REAL_INTERFACE "* ]]; then
-		die "\`$INTERFACE' is not a WireGuard interface"
-	fi
+	get_real_interface || die "\`$INTERFACE' is not a WireGuard interface"
 	save_config
 }