fix: request DHCP classless static routes (option 121) in udhcpc

Add -O 121 flag to udhcpc calls in S30eth to request DHCP option 121
(classless static routes). This allows network administrators to push
specific routes for isolated network segments.

Cherry-picked from: sipeed#749
Original author: phaidros7

Author: winstar0070

kvmapp/system/init.d/S30eth

@@ -39,15 +39,15 @@ start() {
         done < /boot/eth.nodhcp
 
         ip a show dev eth0 | grep inet > /dev/null || {
-            udhcpc -i eth0 -t 3 -T 1 -A 5 -b -p /run/udhcpc.eth0.pid &>/dev/null
+            udhcpc -i eth0 -t 3 -T 1 -A 5 -b -O 121 -p /run/udhcpc.eth0.pid &>/dev/null
             ip a show dev eth0 | grep inet > /dev/null
         } || {
             inet=$RESERVE_INET
             addr=${inet%/*}
             ip a add "$inet" brd + dev eth0
         } || exit 1
     else
-        udhcpc -i eth0 -t 10 -T 1 -A 5 -b -p /run/udhcpc.eth0.pid &
+        udhcpc -i eth0 -t 10 -T 1 -A 5 -b -O 121 -p /run/udhcpc.eth0.pid &
     fi
 }
 
@@ -65,4 +65,4 @@ case "$1" in
         $0 start
         ;;
     *) exit 1 ;;
-esac
+esac