base-files: use less entropy when generating ULAs

SVN-Revision: 36865

package/base-files/Makefile

@@ -11,7 +11,7 @@ include $(INCLUDE_DIR)/kernel.mk
 include $(INCLUDE_DIR)/version.mk
 
 PKG_NAME:=base-files
-PKG_RELEASE:=138
+PKG_RELEASE:=139
 
 PKG_FILE_DEPENDS:=$(PLATFORM_DIR)/ $(GENERIC_PLATFORM_DIR)/base-files/
 PKG_BUILD_DEPENDS:=opkg/host

package/base-files/files/etc/uci-defaults/12_network-generate-ula

@@ -1,13 +1,10 @@
 #!/bin/sh
 
 [ "$(uci get network.globals.ula_prefix)" != "auto" ] && exit 0
-# Sometimes results are empty, therefore try until it works...          
-local r1 r2 r3
-while [ -z "$r1" -o -z "$r2" -o -z "$r3" ]; do
-	r1=$(printf "%02x" $(($(</dev/urandom tr -dc 0-9 | dd bs=9 count=1) % 256)))
-	r2=$(printf "%01x" $(($(</dev/urandom tr -dc 0-9 | dd bs=9 count=1) % 65536)))
-	r3=$(printf "%01x" $(($(</dev/urandom tr -dc 0-9 | dd bs=9 count=1) % 65536)))
-done
+
+r1=$(dd if=/dev/urandom bs=1 count=1 |hexdump -e '1/1 "%02x"')
+r2=$(dd if=/dev/urandom bs=2 count=1 |hexdump -e '2/1 "%02x"')
+r3=$(dd if=/dev/urandom bs=2 count=1 |hexdump -e '2/1 "%02x"')
 
 uci -q batch <<-EOF >/dev/null
 	set network.globals.ula_prefix=fd$r1:$r2:$r3::/48