wg-quick: bring interface up while setting MTU

This avoids another ip(8) invocation for little benefit.
Confirmed to work with iproute2 and busybox.

Signed-off-by: Aaron Jones <aaronmdjones@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

diff --git a/src/wg-quick/linux.bash b/src/wg-quick/linux.bash
index 48ce16356ecc97860873fd4c4fbda82e517af757..fd62316c58ade1fb2852ce9edecae2afb270ba49 100755 (executable)
--- a/src/wg-quick/linux.bash
+++ b/src/wg-quick/linux.bash
@@ -112,18 +112,14 @@ del_if() {
        cmd ip link delete dev "$INTERFACE"
 }
 
-up_if() {
-       cmd ip link set "$INTERFACE" up
-}
-
 add_addr() {
        cmd ip address add "$1" dev "$INTERFACE"
 }
 
-set_mtu() {
+set_mtu_up() {
        local mtu=0 endpoint output
        if [[ -n $MTU ]]; then
-               cmd ip link set mtu "$MTU" dev "$INTERFACE"
+               cmd ip link set mtu "$MTU" up dev "$INTERFACE"
                return
        fi
        while read -r _ endpoint; do
@@ -136,7 +132,7 @@ set_mtu() {
                [[ ( $output =~ mtu\ ([0-9]+) || ( $output =~ dev\ ([^ ]+) && $(ip link show dev "${BASH_REMATCH[1]}") =~ mtu\ ([0-9]+) ) ) && ${BASH_REMATCH[1]} -gt $mtu ]] && mtu="${BASH_REMATCH[1]}"
        fi
        [[ $mtu -gt 0 ]] || mtu=1500
-       cmd ip link set mtu $(( mtu - 80 )) dev "$INTERFACE"
+       cmd ip link set mtu $(( mtu - 80 )) up dev "$INTERFACE"
 }
 
 resolvconf_iface_prefix() {
@@ -286,8 +282,7 @@ cmd_up() {
        for i in "${ADDRESSES[@]}"; do
                add_addr "$i"
        done
-       set_mtu
-       up_if
+       set_mtu_up
        set_dns
        for i in $(while read -r _ i; do for i in $i; do [[ $i =~ ^[0-9a-z:.]+/[0-9]+$ ]] && echo "$i"; done; done < <(wg show "$INTERFACE" allowed-ips) | sort -nr -k 2 -t /); do
                add_route "$i"