add Ipaddr of_octet functions

lib/ipaddr.ml

@@ -1137,6 +1137,15 @@ let with_port_of_string ~default s =
       Ok (ipv6, default))
   with Parse_error (msg, _) -> Error (`Msg ("Ipaddr: " ^ msg))
 
+let of_octets_exn bs =
+  match String.length bs with
+  | 4 -> V4 (V4.of_octets_exn bs)
+  | 16 -> V6 (V6.of_octets_exn bs)
+  | _ -> raise (Parse_error ("octets must be of length 4 or 16", bs))
+
+let of_octets bs = try_with_result of_octets_exn bs
+let to_octets i = match i with V4 p -> V4.to_octets p | V6 p -> V6.to_octets p
+
 let v6_of_v4 v4 =
   V6.(Prefix.(network_address ipv4_mapped (of_int32 (0l, 0l, 0l, v4))))
 

lib/ipaddr.mli

@@ -638,6 +638,19 @@ val with_port_of_string :
     - [::1:8080] returns the IPv6 [::1:8080] with the [default] port
     - [0:0:0:0:0:0:0:1:8080] returns [::1] with the port [8080]. *)
 
+val of_octets_exn : string -> t
+(** [of_octets_exn octets] is the address {!t} represented by [octets]. The
+    [octets] must be 4 bytes long for a {!V4} or 16 if a {!V6}. Raises
+    {!Parse_error} if [octets] is not a valid representation of an address. *)
+
+val of_octets : string -> (t, [> `Msg of string ]) result
+(** Same as {!of_octets_exn} but returns a result type instead of raising an
+    exception. *)
+
+val to_octets : t -> string
+(** [to_octets addr] returns the bytes representing the [addr] octets, which
+    will be 4 bytes long if addr is a {!V4} or 16 if a {!V6}. *)
+
 val v4_of_v6 : V6.t -> V4.t option
 (** [v4_of_v6 ipv6] is the IPv4 representation of the IPv6 address [ipv6]. If
     [ipv6] is not an IPv4-mapped address, None is returned. *)