Add functions for read current default route and DNS settings

alterator-net-functions/alterator-net-functions

@@ -404,6 +404,22 @@ write_iface_default_gw()
 	printf 'default via %s\n' "$2" >>"$1/ipv${p}route"
 }
 
+# read_iface_current_default_gw <iface_path> [ ip_version ]
+read_iface_current_default_gw()
+{
+	local name="${1##*/}"
+	local p="${2:-4}" r= d=
+
+	eval "r=\$__default_ipv${p}_gw_re"
+
+	/sbin/ip -$p route show to default dev "$name" 2>/dev/null | \
+		sed -n -e "s/$r/\1/p" \
+			   -e 't l1' \
+			   -e 'b' \
+			   -e ': l1' \
+			   -e 'q'
+}
+
 read_iface_search()
 {
     local retval
@@ -422,6 +438,11 @@ write_iface_search()
 	[ -s "$resolvconf_file" ] || rm -f -- "$resolvconf_file"
 }
 
+read_current_search()
+{
+	read_iface_search /etc
+}
+
 read_iface_dns()
 {
     local retval
@@ -444,6 +465,11 @@ write_iface_dns()
 	[ -s "$resolvconf_file" ] || rm -f -- "$resolvconf_file"
 }
 
+read_current_dns()
+{
+	read_iface_dns /etc
+}
+
 # NOTE: For bond/bridge interfaces HOST variable means
 # "_This_ interface is a host for interfaces in the list".
 # But for VLAN interfaces HOST variable has opposite meaning: