1# Configure the MTU for the interface
2
3mtu_dir="$state_dir/mtu"
4
5set_mtu()
6{
7	local mtu=$1
8
9	if [ -w /sys/class/net/$interface/mtu ]; then
10		echo "$mtu" >/sys/class/net/$interface/mtu
11	else
12		ifconfig "$interface" mtu "$mtu"
13	fi
14}
15
16if [ "$reason" = PREINIT -a -e "$mtu_dir/$interface" ]; then
17	rm "$mtu_dir/$interface"
18elif [ -n "$new_interface_mtu" ] && $if_up; then
19	# The smalled MTU dhcpcd can work with is 576
20	if [ "$new_interface_mtu" -ge 576 ]; then
21		if set_mtu "$new_interface_mtu"; then
22			syslog info "MTU set to $new_interface_mtu"
23			# Save the MTU so we can restore it later
24			if [ ! -e "$mtu_dir/$interface" ]; then
25				mkdir -p "$mtu_dir"
26				echo "$ifmtu" > "$mtu_dir/$interface"
27			fi
28		fi
29	fi
30elif [ -e "$mtu_dir/$interface" ]; then
31	if $if_up || $if_down; then
32		# No MTU in this state, so restore the prior MTU
33		mtu=$(cat "$mtu_dir/$interface")
34		syslog info "MTU restored to $mtu"
35		set_mtu "$mtu"
36		rm "$mtu_dir/$interface"
37	fi
38fi
39