From: Roy Marples <roy@marples.name>
Date: Mon, 27 Jul 2015 09:31:35 +0000 (+0000)
Subject: Only apply interface MTU on DHCP messages, or static IPv4 configuration.
X-Git-Tag: v6.9.2~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=67aeb589bf8e3f163bd4919ad8bcb9ce874aeaca;p=thirdparty%2Fdhcpcd.git

Only apply interface MTU on DHCP messages, or static IPv4 configuration.
---

diff --git a/dhcpcd-hooks/10-mtu b/dhcpcd-hooks/10-mtu
index f8657cbd..f563624c 100644
--- a/dhcpcd-hooks/10-mtu
+++ b/dhcpcd-hooks/10-mtu
@@ -13,26 +13,31 @@ set_mtu()
 	fi
 }
 
-if [ "$reason" = PREINIT -a -e "$mtu_dir/$interface" ]; then
-	rm "$mtu_dir/$interface"
-elif [ -n "$new_interface_mtu" ] && $if_up; then
-	# The smalled MTU dhcpcd can work with is 576
-	if [ "$new_interface_mtu" -ge 576 ]; then
-		if set_mtu "$new_interface_mtu"; then
-			syslog info "MTU set to $new_interface_mtu"
-			# Save the MTU so we can restore it later
-			if [ ! -e "$mtu_dir/$interface" ]; then
-				mkdir -p "$mtu_dir"
-				echo "$ifmtu" > "$mtu_dir/$interface"
+# Only set interface MTU on either a DHCP option recieved or a static
+# configuration for IPv4 which is wrapped in the DHCP setup.
+# IPv6 MTU is done via routing.
+if [ "$ifsuffix" = ".dhcp" ]; then
+	if [ "$reason" = PREINIT -a -e "$mtu_dir/$interface" ]; then
+		rm "$mtu_dir/$interface"
+	elif [ -n "$new_interface_mtu" ] && $if_up; then
+		# The smalled MTU dhcpcd can work with is 576
+		if [ "$new_interface_mtu" -ge 576 ]; then
+			if set_mtu "$new_interface_mtu"; then
+				syslog info "MTU set to $new_interface_mtu"
+				# Save the MTU so we can restore it later
+				if [ ! -e "$mtu_dir/$interface" ]; then
+					mkdir -p "$mtu_dir"
+					echo "$ifmtu" > "$mtu_dir/$interface"
+				fi
 			fi
 		fi
-	fi
-elif [ -e "$mtu_dir/$interface" ]; then
-	if $if_up || $if_down; then
-		# No MTU in this state, so restore the prior MTU
-		mtu=$(cat "$mtu_dir/$interface")
-		syslog info "MTU restored to $mtu"
-		set_mtu "$mtu"
-		rm "$mtu_dir/$interface"
+	elif [ -e "$mtu_dir/$interface" ]; then
+		if $if_up || $if_down; then
+			# No MTU in this state, so restore the prior MTU
+			mtu=$(cat "$mtu_dir/$interface")
+			syslog info "MTU restored to $mtu"
+			set_mtu "$mtu"
+			rm "$mtu_dir/$interface"
+		fi
 	fi
 fi