Let diameter_{tcp,sctp} be configured with permissible remote addresses

Option 'accept' allows remote addresses to be configured as tuples or
regular expressions. The remote addresses for any incoming (aka
accepted) connection/association are matched against the configured
values, any non-matching address causing the connection/association to
be aborted.

6 files changed, 174 insertions, 52 deletions

diff --git a/lib/diameter/doc/src/diameter_sctp.xml b/lib/diameter/doc/src/diameter_sctp.xml
index df140b16b9..5fe14b1ef6 100644
--- a/lib/diameter/doc/src/diameter_sctp.xml
+++ b/lib/diameter/doc/src/diameter_sctp.xml
@@ -70,10 +70,15 @@ and implements the behaviour documented in
 <v>Type = connect | accept</v>
 <v>Ref = &mod_transport_ref;</v>
 <v>Svc = #diameter_service{}</v>
-<v>Opt = {raddr, &ip_address;} | {rport, integer()} | term()</v>
+<v>Opt = OwnOpt | SctpOpt</v>
 <v>Pid = pid()</v>
 <v>LAddr = &ip_address;</v>
 <v>Reason = term()</v>
+<v>OwnOpt = {raddr, &ip_address;}
+          | {rport, integer()}
+          | {accept, Match}</v>
+<v>SctpOpt = term()</v>
+<v>Match = &ip_address; | string() | [Match]</v>
 </type>
 <desc>
 
@@ -85,9 +90,20 @@ Options <c>raddr</c> and <c>rport</c> specify the remote address
 and port for a connecting transport and not valid for a listening
 transport: the former is required while latter defaults to 3868 if
 unspecified.
-More than one <c>raddr</c> option can be specified, in which case the
+Mupltiple <c>raddr</c> options can be specified, in which case the
 connecting transport in question attempts each in sequence until
-an association is established.
+an association is established.</p>
+
+<p>
+Option <c>accept</c> specifies remote addresses for a listening
+transport and is not valid for a connecting transport.
+If specified, a remote address that does not match one of the
+specified addresses causes the association to be aborted.
+Multiple <c>accept</c> options can be specified.
+A string-valued <c>Match</c> that does not parse as an address is
+interpreted as a regular expression.</p>
+
+<p>
 Remaining options are any accepted by &gen_sctp_open1;, with the exception
 of options <c>mode</c>, <c>binary</c>, <c>list</c>, <c>active</c>
 and <c>sctp_events</c>.
diff --git a/lib/diameter/doc/src/diameter_tcp.xml b/lib/diameter/doc/src/diameter_tcp.xml
index 8e509aa829..ce4d6cfd0f 100644
--- a/lib/diameter/doc/src/diameter_tcp.xml
+++ b/lib/diameter/doc/src/diameter_tcp.xml
@@ -96,10 +96,12 @@ before configuring TLS capability on diameter transports.</p>
 <v>Reason = term()</v>
 <v>OwnOpt = {raddr, &ip_address;}
           | {rport, integer()}
+          | {accept, Match}
           | {port, integer()}
           | {fragment_timer, infinity | 0..16#FFFFFFFF}</v>
 <v>SslOpt = {ssl_options, true | list()}</v>
 <v>TcpOpt = term()</v>
+<v>Match = &ip_address; | string() | [Match]</v>
 </type>
 <desc>
 
@@ -109,7 +111,18 @@ The start function required by &man_transport;.</p>
 <p>
 Options <c>raddr</c> and <c>rport</c> specify the remote address
 and port for a connecting transport and are not valid for a listening
-transport.
+transport.</p>
+
+<p>
+Option <c>accept</c> specifies remote addresses for a listening
+transport and is not valid for a connecting transport.
+If specified, a remote address that does not match one of the
+specified addresses causes the connection to be aborted.
+Multiple <c>accept</c> options can be specified.
+A string-valued <c>Match</c> that does not parse as an address is
+interpreted as a regular expression.</p>
+
+<p>
 Option <c>ssl_options</c> must be specified for a transport
 that should support TLS: a value of <c>true</c> results in a
 TLS handshake immediately upon connection establishment while
diff --git a/lib/diameter/src/base/diameter_peer.erl b/lib/diameter/src/base/diameter_peer.erl
index 0d2efd4d1f..e5d4b28766 100644
--- a/lib/diameter/src/base/diameter_peer.erl
+++ b/lib/diameter/src/base/diameter_peer.erl
@@ -25,7 +25,8 @@
 -export([recv/2,
          up/1,
          up/2,
-         up/3]).
+         up/3,
+         match/2]).
 
 %% ... and the stack.
 -export([start/1,
@@ -63,16 +64,16 @@
 -define(DEFAULT_TCFG, []).
 -define(DEFAULT_TTMO, infinity).
 
-%%% ---------------------------------------------------------------------------
-%%% # notify/3
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # notify/3
+%% ---------------------------------------------------------------------------
 
 notify(Nodes, SvcName, T) ->
     rpc:abcast(Nodes, ?SERVER, {notify, SvcName, T}).
 
-%%% ---------------------------------------------------------------------------
-%%% # start/1
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # start/1
+%% ---------------------------------------------------------------------------
 
 -spec start({T, [Opt], #diameter_service{}})
    -> {TPid, [Addr], Tmo, Data}
@@ -180,9 +181,34 @@ start(T, [M|Ms], Cfg, Svc, Tmo, Rest, Errs) ->
 start(Mod, Args) ->
     apply(Mod, start, Args).
 
-%%% ---------------------------------------------------------------------------
-%%% # up/1-3
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # match/2
+%% ---------------------------------------------------------------------------
+
+match(Addrs, Matches)
+  when is_list(Addrs) ->
+    lists:all(fun(A) -> match1(A, Matches) end, Addrs).
+
+match1(Addr, Matches)
+  when not is_integer(hd(Matches)) ->
+    lists:any(fun(M) -> match1(Addr, M) end, Matches);
+
+match1(Addr, Match) ->
+    match(Addr, addr(Match), Match).
+
+match(Addr, {ok, A}, _) ->
+    Addr == A;
+match(Addr, {error, _}, RE) ->
+    match == re:run(inet_parse:ntoa(Addr), RE, [{capture, none}]).
+
+addr([_|_] = A) ->
+    inet_parse:address(A);
+addr(A) ->
+    {ok, A}.
+
+%% ---------------------------------------------------------------------------
+%% # up/1-3
+%% ---------------------------------------------------------------------------
 
 up(Pid) ->  %% accepting transport
     ifc_send(Pid, {self(), connected}).
@@ -193,16 +219,16 @@ up(Pid, Remote) ->  %% connecting transport
 up(Pid, Remote, LAddrs) -> %% connecting transport
     ifc_send(Pid, {self(), connected, Remote, LAddrs}).
 
-%%% ---------------------------------------------------------------------------
-%%% # recv/2
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # recv/2
+%% ---------------------------------------------------------------------------
 
 recv(Pid, Pkt) ->
     ifc_send(Pid, {recv, Pkt}).
 
-%%% ---------------------------------------------------------------------------
-%%% # send/2
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # send/2
+%% ---------------------------------------------------------------------------
 
 send(Pid, #diameter_packet{transport_data = undefined,
 			   bin = Bin}) ->
@@ -211,16 +237,16 @@ send(Pid, #diameter_packet{transport_data = undefined,
 send(Pid, Pkt) ->
     ifc_send(Pid, {send, Pkt}).
 
-%%% ---------------------------------------------------------------------------
-%%% # close/1
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # close/1
+%% ---------------------------------------------------------------------------
 
 close(Pid) ->
     ifc_send(Pid, {close, self()}).
 
-%%% ---------------------------------------------------------------------------
-%%% # abort/1
-%%% ---------------------------------------------------------------------------
+%% ---------------------------------------------------------------------------
+%% # abort/1
+%% ---------------------------------------------------------------------------
 
 abort(Pid) ->
     exit(Pid, shutdown).
@@ -241,16 +267,16 @@ state() ->
 uptime() ->
     call(uptime).
 
-%%% ----------------------------------------------------------
-%%% # init(Role)
-%%% ----------------------------------------------------------
+%% ----------------------------------------------------------
+%% # init(Role)
+%% ----------------------------------------------------------
 
 init([]) ->
     {ok, #state{}}.
 
-%%% ----------------------------------------------------------
-%%% # handle_call(Request, From, State)
-%%% ----------------------------------------------------------
+%% ----------------------------------------------------------
+%% # handle_call(Request, From, State)
+%% ----------------------------------------------------------
 
 handle_call(state, _, State) ->
     {reply, State, State};
@@ -262,17 +288,17 @@ handle_call(Req, From, State) ->
     ?UNEXPECTED([Req, From]),
     {reply, nok, State}.
 
-%%% ----------------------------------------------------------
-%%% # handle_cast(Request, State)
-%%% ----------------------------------------------------------
+%% ----------------------------------------------------------
+%% # handle_cast(Request, State)
+%% ----------------------------------------------------------
 
 handle_cast(Msg, State) ->
     ?UNEXPECTED([Msg]),
     {noreply, State}.
 
-%%% ----------------------------------------------------------
-%%% # handle_info(Request, State)
-%%% ----------------------------------------------------------
+%% ----------------------------------------------------------
+%% # handle_info(Request, State)
+%% ----------------------------------------------------------
 
 %% Remote service is distributing a message.
 handle_info({notify, SvcName, T}, S) ->
diff --git a/lib/diameter/src/transport/diameter_sctp.erl b/lib/diameter/src/transport/diameter_sctp.erl
index de3333e605..49a530b4eb 100644
--- a/lib/diameter/src/transport/diameter_sctp.erl
+++ b/lib/diameter/src/transport/diameter_sctp.erl
@@ -57,6 +57,9 @@
 %% The default port for a listener.
 -define(DEFAULT_PORT, 3868).  %% RFC 3588, ch 2.1
 
+%% Remote addresses to accept connections from.
+-define(DEFAULT_ACCEPT, []).  %% any
+
 %% How long a listener with no associations lives before offing
 %% itself.
 -define(LISTENER_TIMEOUT, 30000).
@@ -68,7 +71,13 @@
 -type connect_option() :: {raddr, inet:ip_address()}
                         | {rport, inet:port_number()}
                         | gen_sctp:open_option().
--type listen_option() :: gen_sctp:open_option().
+
+-type match() :: inet:ip_address()
+               | string()
+               | [match()].
+
+-type listen_option() :: {accept, match()}
+                       | gen_sctp:open_option().
 
 -type uint() :: non_neg_integer().
 
@@ -77,7 +86,7 @@
         {parent  :: pid(),
          mode :: {accept, pid()}
                | accept
-               | {connect, {list(inet:ip_address()), uint(), list()}}
+               | {connect, {[inet:ip_address()], uint(), list()}}
                         %% {RAs, RP, Errors}
                | connect,
          socket   :: gen_sctp:sctp_socket(),
@@ -94,7 +103,8 @@
          tmap = ets:new(?MODULE, []) :: ets:tid(),
              %% {MRef, Pid|AssocId}, {AssocId, Pid}
          pending = {0, ets:new(?MODULE, [ordered_set])},
-         tref      :: reference()}).
+         tref      :: reference(),
+         accept    :: [match()]}).
 %% Field tmap is used to map an incoming message or event to the
 %% relevent transport process. Field pending implements a queue of
 %% transport processes to which an association has been assigned (at
@@ -184,12 +194,14 @@ init(T) ->
 
 %% A process owning a listening socket.
 i({listen, Ref, {Opts, Addrs}}) ->
-    {LAs, Sock} = AS = open(Addrs, Opts, ?DEFAULT_PORT),
+    {[Matches], Rest} = proplists:split(Opts, [accept]),
+    {LAs, Sock} = AS = open(Addrs, Rest, ?DEFAULT_PORT),
     proc_lib:init_ack({ok, self(), LAs}),
     ok = gen_sctp:listen(Sock, true),
     true = diameter_reg:add_new({?MODULE, listener, {Ref, AS}}),
     start_timer(#listener{ref = Ref,
-                          socket = Sock});
+                          socket = Sock,
+                          accept = accept(Matches)});
 
 %% A connecting transport.
 i({connect, Pid, Opts, Addrs, Ref}) ->
@@ -326,6 +338,9 @@ handle_call({{accept, Ref}, Pid}, _, #listener{ref = Ref,
     {TPid, NewS} = accept(Ref, Pid, S),
     {reply, {ok, TPid}, NewS#listener{count = N+1}};
 
+handle_call(T, From, {listener,_,_,_,_,_,_} = S) -> % started in old code
+    handle_call(T, From, upgrade(S));
+
 handle_call(_, _, State) ->
     {reply, nok, State}.
 
@@ -344,7 +359,10 @@ handle_info(T, #transport{} = S) ->
     {noreply, #transport{} = t(T,S)};
 
 handle_info(T, #listener{} = S) ->
-    {noreply, #listener{} = l(T,S)}.
+    {noreply, #listener{} = l(T,S)};
+
+handle_info(T, {listener,_,_,_,_,_,_} = S) -> % started in old code
+    handle_info(T, upgrade(S)).
 
 %% ---------------------------------------------------------------------------
 %% # code_change/3
@@ -378,6 +396,9 @@ terminate(_, #listener{socket = Sock}) ->
 
 %% ---------------------------------------------------------------------------
 
+upgrade(S) ->
+    #listener{} = erlang:append_element(S, ?DEFAULT_ACCEPT).
+
 putr(Key, Val) ->
     put({?MODULE, Key}, Val).
 
@@ -401,7 +422,7 @@ l({sctp, Sock, _RA, _RP, Data} = Msg, #listener{socket = Sock} = S) ->
 
     try find(Id, Data, S) of
         {TPid, NewS} ->
-            TPid ! {peeloff, peeloff(Sock, Id, TPid), Msg},
+            TPid ! {peeloff, peeloff(Sock, Id, TPid), Msg, S#listener.accept},
             NewS;
         false ->
             S
@@ -475,11 +496,14 @@ t(T,S) ->
 %% transition/2
 
 %% Listening process is transfering ownership of an association.
-transition({peeloff, Sock, {sctp, LSock, _RA, _RP, _Data} = Msg},
+transition({peeloff, Sock, {sctp, LSock, _RA, _RP, _Data} = Msg, Matches},
            #transport{mode = {accept, _},
                       socket = LSock}
            = S) ->
+    ok = accept_peer(Sock, Matches),
     transition(Msg, S#transport{socket = Sock});
+transition({peeloff = T, _Sock, _Msg} = T, #transport{} = S) ->% from old code
+    transition(erlang:append_element(T, ?DEFAULT_ACCEPT), S);
 
 %% Incoming message.
 transition({sctp, _Sock, _RA, _RP, Data}, #transport{socket = Sock} = S) ->
@@ -525,6 +549,27 @@ transition({resolve_port, Pid}, #transport{socket = Sock})
 
 %% Crash on anything unexpected.
 
+ok({ok, T}) ->
+    T;
+ok(T) ->
+    x(T).
+
+%% accept_peer/2
+
+accept_peer(_, []) ->
+    ok;
+
+accept_peer(Sock, Matches) ->
+    {RAddrs, _} = ok(inet:peername(Sock)),
+    diameter_peer:match(RAddrs, Matches)
+        orelse x({accept, RAddrs, Matches}),
+    ok.
+
+%% accept/1
+
+accept(Opts) ->
+    [[M] || {accept, M} <- Opts].
+
 %% accept/3
 %%
 %% Start a new transport process or use one that's already been
diff --git a/lib/diameter/src/transport/diameter_tcp.erl b/lib/diameter/src/transport/diameter_tcp.erl
index ce54effab6..4d1b8bec51 100644
--- a/lib/diameter/src/transport/diameter_tcp.erl
+++ b/lib/diameter/src/transport/diameter_tcp.erl
@@ -85,12 +85,16 @@
 
 -type connect_option() :: {raddr, inet:ip_address()}
                         | {rport, pos_integer()}
-                        | option()
                         | {ssl_options, true | [ssl:connect_option()]}
+                        | option()
                         | ssl:connect_option()
                         | gen_tcp:connect_option().
 
--type listen_option() :: option()
+-type match() :: inet:ip_address()
+               | string()
+               | [match()].
+
+-type listen_option() :: {accept, match()}
                        | {ssl_options, true | [ssl:listen_option()]}
                        | ssl:listen_option()
                        | gen_tcp:listen_option().
@@ -241,8 +245,8 @@ laddr([{ip, Addr}], _, _) ->
     Addr.
 
 own(Opts) ->
-    {Own, Rest} = proplists:split(Opts, [fragment_timer]),
-    {lists:append(Own), Rest}.
+    {[Own], Rest} = proplists:split(Opts, [fragment_timer]),
+    {Own, Rest}.
 
 ssl(Opts) ->
     {[SslOpts], Rest} = proplists:split(Opts, [ssl_options]),
@@ -271,9 +275,11 @@ init(Type, Ref, Mod, Pid, _, Opts, Addrs) ->
 %% init/6
 
 init(accept = T, Ref, Mod, Pid, Opts, Addrs) ->
-    {LAddr, LSock} = listener(Ref, {Mod, Opts, Addrs}),
+    {[Matches], Rest} = proplists:split(Opts, [accept]),
+    {LAddr, LSock} = listener(Ref, {Mod, Rest, Addrs}),
     proc_lib:init_ack({ok, self(), [LAddr]}),
     Sock = ok(accept(Mod, LSock)),
+    ok = accept_peer(Mod, Sock, accept(Matches)),
     publish(Mod, T, Ref, Sock),
     diameter_peer:up(Pid),
     Sock;
@@ -312,6 +318,22 @@ ok(No) ->
 x(Reason) ->
     exit({shutdown, Reason}).
 
+%% accept_peer/3
+
+accept_peer(_Mod, _Sock, []) ->
+    ok;
+
+accept_peer(Mod, Sock, Matches) ->
+    {RAddr, _} = ok(peername(Mod, Sock)),
+    diameter_peer:match([RAddr], Matches)
+        orelse x({accept, RAddr, Matches}),
+    ok.
+
+%% accept/1
+
+accept(Opts) ->
+    [[M] || {accept, M} <- Opts].
+
 %% listener/2
 
 listener(LRef, T) ->
diff --git a/lib/diameter/test/diameter_util.erl b/lib/diameter/test/diameter_util.erl
index aa489fef5f..92c72c84e7 100644
--- a/lib/diameter/test/diameter_util.erl
+++ b/lib/diameter/test/diameter_util.erl
@@ -336,7 +336,7 @@ opts(Prot, T) ->
      {transport_config, [{ip, ?ADDR}, {port, 0} | opts(T)]}].
 
 opts(listen) ->
-    [];
+    [{accept, M} || M <- [{256,0,0,1}, ["256.0.0.1", ["^.+$"]]]];
 opts(PortNr) ->
     [{raddr, ?ADDR}, {rport, PortNr}].