Merge pull request #147 from euanh/CA-89974

CA-89974: Live migrate fails on IPv6-preferring hosts

Author: robhoes

http-svr/http.ml

@@ -16,6 +16,7 @@
 
 open Stringext
 open Pervasiveext
+open Fun
 
 exception Http_parse_failure
 exception Unauthorised of string
@@ -572,12 +573,19 @@ module Url = struct
 	type t = scheme * data
 
 	let of_string url =
-		let host x = match String.split ':' x with
-			| host :: _ -> host
-			| _ -> failwith (Printf.sprintf "Failed to parse host: %s" x) in
-		let port x = match String.split ':' x with
-			| _ :: port :: _ -> Some (int_of_string port)
-			| _ -> None in
+		let host x =
+			let open String in
+			try x |> sub_after '[' |> sub_before ']' with Not_found ->   (* [<ipv6-literal>]... *)
+			try x |> sub_before ':' with Not_found ->                    (* <hostname|ipv4-literal>:... *)
+			x in                                                         (* <hostname|ipv4-literal> *)
+		let port x =
+			let port_part =
+				let open String in
+				try x |> sub_after ']' |> sub_after ':' with Not_found ->  (* ...]:port *)
+				try x |> sub_after ']' with Not_found ->                   (* ...] *)
+				try x |> sub_after ':' with Not_found ->                   (* ...:port *)
+				"" in                                                      (* no port *)
+			try Some (int_of_string port_part) with _ -> None in
 		let uname_password_host_port x = match String.split '@' x with
 			| [ _ ] -> None, host x, port x
 			| [ uname_password; host_port ] ->
@@ -608,6 +616,10 @@ module Url = struct
 		let params = if params = [] then "" else "?" ^ (kvpairs params) in
 		uri ^ params
 
+	(* Wrap a literal IPv6 address in square brackets; otherwise pass through *)
+	let maybe_wrap_IPv6_literal addr = 
+		if Unixext.domain_of_addr addr = Some Unix.PF_INET6 then "[" ^ addr ^ "]" else addr
+
 	let to_string = function
 		| File { path = path }, data -> Printf.sprintf "file:%s%s" path (data_to_string data) (* XXX *)
 		| Http h, data ->
@@ -618,7 +630,7 @@ module Url = struct
 				| Some x -> Printf.sprintf ":%d" x
 				| _ -> "" in
 			Printf.sprintf "http%s://%s%s%s%s" (if h.ssl then "s" else "")
-				userpassat h.host colonport (data_to_string data)
+				userpassat (maybe_wrap_IPv6_literal h.host) colonport (data_to_string data)
 
 	let get_uri (scheme, data) = data.uri
 	let set_uri (scheme, data) u = (scheme, { data with uri = u })

http-svr/http.mli

@@ -191,6 +191,9 @@ module Url : sig
 
 	val of_string: string -> t
 
+	(** Wrap a literal IPv6 address in square brackets; otherwise pass through *)
+	val maybe_wrap_IPv6_literal : string -> string
+	
 	val to_string: t -> string
 
 	val get_uri: t -> string

stdext/stringext.ml

@@ -214,4 +214,10 @@ let sub_to_end s start =
 	let length = String.length s in
 	String.sub s start (length - start)
 
+let sub_before c s = 
+	String.sub s 0 (String.index s c)
+
+let sub_after c s =
+	sub_to_end s (String.index s c + 1)
+	
 end

stdext/stringext.mli

@@ -120,4 +120,10 @@ module String :
 
     (** a substring from the specified position to the end of the string *)
     val sub_to_end : string -> int -> string
+    
+    (** a substring from the start of the string to the first occurrence of a given character, excluding the character *)
+    val sub_before : char -> string -> string
+    
+    (** a substring from  the first occurrence of a given character to the end of the string, excluding the character *)
+    val sub_after : char -> string -> string
   end

stdext/unixext.ml

@@ -252,21 +252,19 @@ let delete_empty_file file_path =
 (** Create a new file descriptor, connect it to host:port and return it *)
 exception Host_not_found of string
 let open_connection_fd host port =
-	let s = Unix.socket Unix.PF_INET Unix.SOCK_STREAM 0 in
-	try 
-	  let he =
-	    try
-	      Unix.gethostbyname host
-	    with
-		Not_found -> raise (Host_not_found host) in
-	  if Array.length he.Unix.h_addr_list = 0
-	  then failwith (Printf.sprintf "Couldn't resolve hostname: %s" host);
-	  let ip = he.Unix.h_addr_list.(0) in
-	  let addr = Unix.ADDR_INET(ip, port) in
-	  Unix.connect s addr;
-	  s
-	with e -> Unix.close s; raise e
-
+	let open Unix in
+	let addrinfo = getaddrinfo host (string_of_int port) [AI_SOCKTYPE SOCK_STREAM] in
+	match addrinfo with 
+	| [] -> 
+		failwith (Printf.sprintf "Couldn't resolve hostname: %s" host)
+	| ai :: _ ->
+		let s = socket ai.ai_family ai.ai_socktype 0 in
+		try
+			connect s ai.ai_addr;
+			s
+		with e ->
+			close s;
+			raise e
 
 let open_connection_unix_fd filename =
 	let s = Unix.socket Unix.PF_UNIX Unix.SOCK_STREAM 0 in
@@ -677,6 +675,13 @@ type statvfs_t = {
 
 external statvfs : string -> statvfs_t = "stub_statvfs"
 
+(** Returns Some Unix.PF_INET or Some Unix.PF_INET6 if passed a valid IP address, otherwise returns None. *)
+let domain_of_addr str =
+	try
+		let addr = Unix.inet_addr_of_string str in
+		Some (Unix.domain_of_sockaddr (Unix.ADDR_INET (addr, 1)))
+	with _ -> None
+
 module Direct = struct
 	type t = Unix.file_descr
 

stdext/unixext.mli

@@ -167,6 +167,9 @@ type statvfs_t = {
 
 val statvfs : string -> statvfs_t
 
+(** Returns Some Unix.PF_INET or Some Unix.PF_INET6 if passed a valid IP address, otherwise returns None. *)
+val domain_of_addr : string -> Unix.socket_domain option
+
 module Direct : sig
 	(** Perform I/O in O_DIRECT mode using 4KiB page-aligned buffers *)