[enh] Add helper for IP address validation

data/apps/helpers.d/ip

@@ -0,0 +1,52 @@
+# Validate an IP address
+#
+# example: ynh_validate_ip 4 111.222.333.444
+#
+# usage: ynh_validate_ip <family> <ip_address>
+#
+# exit code : 0 for valid ip addresses, 1 otherwise
+ynh_validate_ip()
+{
+  # http://stackoverflow.com/questions/319279/how-to-validate-ip-address-in-python#319298
+  
+  IP_ADDRESS_FAMILY=$1
+  IP_ADDRESS=$2
+  
+  [ "$IP_ADDRESS_FAMILY" == "4" ] || [ "$IP_ADDRESS_FAMILY" == "6" ] || return 1
+  
+  python /dev/stdin << EOF
+import socket
+import sys
+family = { "4" : socket.AF_INET, "6" : socket.AF_INET6 }
+try:
+    socket.inet_pton(family["$IP_ADDRESS_FAMILY"], "$IP_ADDRESS")
+except socket.error:
+    sys.exit(1)
+sys.exit(0)
+EOF
+}
+
+# Validate an IPv4 address
+#
+# example: ynh_validate_ip4 111.222.333.444
+#
+# usage: ynh_validate_ip4 <ip_address>
+#
+# exit code : 0 for valid ipv4 addresses, 1 otherwise
+ynh_validate_ip4()
+{
+  ynh_validate_ip 4 $1
+}
+
+
+# Validate an IPv6 address
+#
+# example: ynh_validate_ip6 2000:dead:beef::1
+#
+# usage: ynh_validate_ip6 <ip_address>
+#
+# exit code : 0 for valid ipv6 addresses, 1 otherwise
+ynh_validate_ip6()
+{
+  ynh_validate_ip 6 $1
+}