Option default_host for handling HTTP requests with ambiguous Host (EJAB-1261)

doc/guide.tex

@@ -826,7 +826,7 @@ The available modules, their purpose and the options allowed by each one are:
     Options: \texttt{certfile}
   \titem{\texttt{ejabberd\_http}}
     Handles incoming HTTP connections.\\
-    Options: \texttt{captcha}, \texttt{certfile}, \texttt{http\_bind}, \texttt{http\_poll},
+    Options: \texttt{captcha}, \texttt{certfile}, \texttt{default\_host}, \texttt{http\_bind}, \texttt{http\_poll},
     \texttt{request\_handlers}, \texttt{tls}, \texttt{trusted\_proxies}, \texttt{web\_admin}\\
 \end{description}
 
@@ -847,6 +847,11 @@ This is a detailed description of each option allowed by the listening modules:
     Simple web page that allows a user to fill a CAPTCHA challenge (see section \ref{captcha}).
   \titem{\{certfile, Path\}} Full path to a file containing the default SSL certificate.
     To define a certificate file specific for a given domain, use the global option \term{domain\_certfile}.
+  \titem{\{default\_host, undefined|HostName\}}
+    If the HTTP request received by ejabberd contains the HTTP header \term{Host}
+    with an ambiguous virtual host that doesn't match any one defined in ejabberd (see \ref{hostnames}),
+    then this configured HostName is set as the request Host.
+    The default value of this option is: \term{undefined}.
   \titem{\{hosts, [Hostname, ...], [HostOption, ...]\}} \ind{options!hosts}
     The external Jabber component that connects to this \term{ejabberd\_service}
     can serve one or more hostnames.

src/web/ejabberd_http.erl

@@ -65,6 +65,7 @@
 		request_tp,
 		request_headers = [],
 		end_of_request = false,
+		default_host,
 		trail = ""
 	       }).
 
@@ -140,9 +141,12 @@ init({SockMod, Socket}, Opts) ->
         end,
     ?DEBUG("S: ~p~n", [RequestHandlers]),
 
+    DefaultHost = gen_mod:get_opt(default_host, Opts, undefined),
+
     ?INFO_MSG("started: ~p", [{SockMod1, Socket1}]),
     State = #state{sockmod = SockMod1,
                    socket = Socket1,
+                   default_host = DefaultHost,
                    request_handlers = RequestHandlers},
     receive_headers(State).
 
@@ -261,8 +265,9 @@ process_header(State, Data) ->
 		   [State#state.socket,
 		    State#state.request_method,
 		    element(2, State#state.request_path)]),
-	    {Host, Port, TP} = get_transfer_protocol(SockMod,
+	    {HostProvided, Port, TP} = get_transfer_protocol(SockMod,
 						     State#state.request_host),
+	    Host = get_host_really_served(State#state.default_host, HostProvided),
 	    State2 = State#state{request_host = Host,
 				 request_port = Port,
 				 request_tp = TP},
@@ -294,6 +299,14 @@ process_header(State, Data) ->
 add_header(Name, Value, State) ->
     [{Name, Value} | State#state.request_headers].
 
+get_host_really_served(undefined, Provided) ->
+    Provided;
+get_host_really_served(Default, Provided) ->
+    case lists:member(Provided, ?MYHOSTS) of
+	true -> Provided;
+	false -> Default
+    end.
+
 %% @spec (SockMod, HostPort) -> {Host::string(), Port::integer(), TP}
 %% where
 %%       SockMod = gen_tcp | tls