Merge branch 'maint'

13 files changed, 361 insertions, 160 deletions

diff --git a/lib/diameter/doc/src/notes.xml b/lib/diameter/doc/src/notes.xml
index 6931788c83..c5df63a7f0 100644
--- a/lib/diameter/doc/src/notes.xml
+++ b/lib/diameter/doc/src/notes.xml
@@ -42,6 +42,36 @@ first.</p>
 
 <!-- ===================================================================== -->
 
+<section><title>diameter 1.9.2</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix broken relay counters.</p>
+          <p>
+	    OTP-12654 in OTP 17.5.3 broke counters in the case of
+	    answer messages received in the relay application.
+	    Counters were accumulated as unknown messages or
+	    no_result_code instead of as relayed messages on the
+	    intended Result-Code and 'Experimental-Result' tuples.</p>
+          <p>
+	    Own Id: OTP-12741</p>
+        </item>
+        <item>
+          <p>
+	    Fix diameter_sctp listener race.</p>
+          <p>
+	    An oversight in OTP-12428 made it possible to start a
+	    transport process that could not establish associations.</p>
+          <p>
+	    Own Id: OTP-12744</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
 <section><title>diameter 1.9.1</title>
 
     <section><title>Known Bugs and Problems</title>
@@ -65,7 +95,7 @@ first.</p>
 	    received in an answer not setting the E-bit. The correct
 	    AVP is now extracted from the incoming message.</p>
           <p>
-	    Own Id: OTP-12654 Aux Id: seq12851 </p>
+	    Own Id: OTP-12654</p>
         </item>
         <item>
           <p>
diff --git a/lib/diameter/src/base/diameter_traffic.erl b/lib/diameter/src/base/diameter_traffic.erl
index ffd2c0afa2..eb4bbae931 100644
--- a/lib/diameter/src/base/diameter_traffic.erl
+++ b/lib/diameter/src/base/diameter_traffic.erl
@@ -131,11 +131,11 @@ peer_down(TPid) ->
 %% incr/4
 %% ---------------------------------------------------------------------------
 
-incr(Dir, #diameter_packet{header = H}, TPid, Dict) ->
-    incr(Dir, H, TPid, Dict);
+incr(Dir, #diameter_packet{header = H}, TPid, AppDict) ->
+    incr(Dir, H, TPid, AppDict);
 
-incr(Dir, #diameter_header{} = H, TPid, Dict) ->
-    incr(TPid, {msg_id(H, Dict), Dir}).
+incr(Dir, #diameter_header{} = H, TPid, AppDict) ->
+    incr(TPid, {msg_id(H, AppDict), Dir}).
 
 %% ---------------------------------------------------------------------------
 %% incr_error/4
@@ -143,26 +143,26 @@ incr(Dir, #diameter_header{} = H, TPid, Dict) ->
 
 %% Identify messages using the application dictionary, not the encode
 %% dictionary, which may differ in the case of answer-message.
-incr_error(Dir, T, Pid, {_Dict, AppDict}) ->
+incr_error(Dir, T, Pid, {_MsgDict, AppDict}) ->
     incr_error(Dir, T, Pid, AppDict);
 
 %% Decoded message without errors.
 incr_error(recv, #diameter_packet{errors = []}, _, _) ->
     ok;
 
-incr_error(recv = D, #diameter_packet{header = H}, TPid, Dict) ->
-    incr_error(D, H, TPid, Dict);
+incr_error(recv = D, #diameter_packet{header = H}, TPid, AppDict) ->
+    incr_error(D, H, TPid, AppDict);
 
 %% Encoded message with errors and an identifiable header ...
-incr_error(send = D, {_, _, #diameter_header{} = H}, TPid, Dict) ->
-    incr_error(D, H, TPid, Dict);
+incr_error(send = D, {_, _, #diameter_header{} = H}, TPid, AppDict) ->
+    incr_error(D, H, TPid, AppDict);
 
 %% ... or not.
 incr_error(send = D, {_,_}, TPid, _) ->
     incr_error(D, unknown, TPid);
 
-incr_error(Dir, #diameter_header{} = H, TPid, Dict) ->
-    incr_error(Dir, msg_id(H, Dict), TPid);
+incr_error(Dir, #diameter_header{} = H, TPid, AppDict) ->
+    incr_error(Dir, msg_id(H, AppDict), TPid);
 
 incr_error(Dir, Id, TPid, _) ->
     incr_error(Dir, Id, TPid).
@@ -179,18 +179,20 @@ incr_error(Dir, Id, TPid) ->
     | Reason
  when Pkt :: #diameter_packet{},
       TPid :: pid(),
-      DictT :: module() | {module(), module(), module()},
+      DictT :: module() | {MsgDict :: module(),
+                           AppDict :: module(),
+                           CommonDict:: module()},
       Counter :: {'Result-Code', integer()}
                | {'Experimental-Result', integer(), integer()},
       Reason :: atom().
 
-incr_rc(Dir, Pkt, TPid, {Dict, _, _} = DictT) ->
+incr_rc(Dir, Pkt, TPid, {_, AppDict, _} = DictT) ->
     try
         incr_result(Dir, Pkt, TPid, DictT)
     catch
         exit: {E,_} when E == no_result_code;
                          E == invalid_error_bit ->
-            incr(TPid, {msg_id(Pkt#diameter_packet.header, Dict), Dir, E}),
+            incr(TPid, {msg_id(Pkt#diameter_packet.header, AppDict), Dir, E}),
             E
     end;
 
@@ -259,7 +261,8 @@ recv(false, #request{ref = Ref, handler = Pid} = Req, _, Pkt, Dict0, _) ->
 %% any others are discarded.
 
 %% ... or not.
-recv(false, false, _, _, _, _) ->
+recv(false, false, TPid, _, _, _) ->
+    incr(TPid, {{unknown, 0}, recv, discarded}),
     ok.
 
 %% spawn_request/4
@@ -307,14 +310,14 @@ recv_request(TPid, Pkt, Dict0, RecvData) -> %% from old code
 
 %% recv_R/5
 
-recv_R({#diameter_app{id = Id, dictionary = Dict} = App, Caps},
+recv_R({#diameter_app{id = Id, dictionary = AppDict} = App, Caps},
        TPid,
        Pkt0,
        Dict0,
        RecvData) ->
-    incr(recv, Pkt0, TPid, Dict),
-    Pkt = errors(Id, diameter_codec:decode(Id, Dict, Pkt0)),
-    incr_error(recv, Pkt, TPid, Dict),
+    incr(recv, Pkt0, TPid, AppDict),
+    Pkt = errors(Id, diameter_codec:decode(Id, AppDict, Pkt0)),
+    incr_error(recv, Pkt, TPid, AppDict),
     {Caps, Pkt, App, recv_R(App, TPid, Dict0, Caps, RecvData, Pkt)};
 %% Note that the decode is different depending on whether or not Id is
 %% ?APP_ID_RELAY.
@@ -522,14 +525,17 @@ send_A(_, _, _, _) ->
 
 %% send_A/6
 
-send_A(T, TPid, DictT, ReqPkt, EvalPktFs, EvalFs) ->
-    reply(T, TPid, DictT, EvalPktFs, ReqPkt),
+send_A(T, TPid, {AppDict, Dict0} = DictT0, ReqPkt, EvalPktFs, EvalFs) ->
+    {MsgDict, Pkt} = reply(T, TPid, DictT0, EvalPktFs, ReqPkt),
+    incr(send, Pkt, TPid, AppDict),
+    incr_rc(send, Pkt, TPid, {MsgDict, AppDict, Dict0}),  %% count outgoing
+    send(TPid, Pkt),
     lists:foreach(fun diameter_lib:eval/1, EvalFs).
 
 %% answer/6
 
 answer({reply, Ans}, _Caps, _Pkt, App, Dict0, _RecvData) ->
-    {dict(App#diameter_app.dictionary, Dict0, Ans), Ans};
+    {msg_dict(App#diameter_app.dictionary, Dict0, Ans), Ans};
 
 answer({call, Opts}, Caps, Pkt, App, Dict0, RecvData) ->
     #diameter_caps{origin_host = {OH,_}}
@@ -552,27 +558,37 @@ answer({answer_message, RC} = T, Caps, Pkt, App, Dict0, _RecvData)  ->
         orelse ?ERROR({invalid_return, T, handle_request, App}),
     answer_message(RC, Caps, Dict0, Pkt).
 
-%% dict/3
+%% msg_dict/3
+%%
+%% Return the dictionary defining the message grammar in question: the
+%% application dictionary or the common dictionary.
+
+msg_dict(AppDict, Dict0, [Msg])
+  when is_list(Msg);
+       is_tuple(Msg) ->
+    msg_dict(AppDict, Dict0, Msg);
 
-%% An incoming answer, not yet decoded.
-dict(Dict, Dict0, #diameter_packet{header
-                                   = #diameter_header{is_request = false,
-                                                      is_error = E},
-                                   msg = undefined}) ->
-    if E -> Dict0; true -> Dict end;
+msg_dict(AppDict, Dict0, Msg) ->
+    choose(is_answer_message(Msg, Dict0), Dict0, AppDict).
 
-dict(Dict, Dict0, [Msg]) ->
-    dict(Dict, Dict0, Msg);
+%% Incoming, not yet decoded.
+is_answer_message(#diameter_packet{header = #diameter_header{} = H,
+                                   msg = undefined},
+                  Dict0) ->
+    is_answer_message([H], Dict0);
 
-dict(Dict, Dict0, #diameter_packet{msg = Msg}) ->
-    dict(Dict, Dict0, Msg);
+is_answer_message(#diameter_packet{msg = Msg}, Dict0) ->
+    is_answer_message(Msg, Dict0);
 
-dict(Dict, Dict0, Msg) ->
-    choose(is_answer_message(Msg, Dict0), Dict0, Dict).
+%% Message sent as a header/avps list.
+is_answer_message([#diameter_header{is_request = R, is_error = E} | _], _) ->
+    E andalso not R;
 
+%% Message sent as a tagged avp/value list.
 is_answer_message([Name | _], _) ->
     Name == 'answer-message';
 
+%% Message sent as a record.
 is_answer_message(Rec, Dict) ->
     try
         'answer-message' == Dict:rec2msg(element(1,Rec))
@@ -642,7 +658,7 @@ resend(false,
 %%
 %% Relay a reply to a relayed request.
 
-%% Answer from the peer: reset the hop by hop identifier and send.
+%% Answer from the peer: reset the hop by hop identifier.
 resend(#diameter_packet{bin = B}
        = Pkt,
        _Caps,
@@ -681,13 +697,13 @@ is_loop(Code, Vid, OH, Dict0, Avps) ->
 %% reply/5
 
 %% Local answer ...
-reply({Dict, Ans}, TPid, {AppDict, Dict0}, Fs, ReqPkt) ->
-    local(Ans, TPid, {Dict, AppDict, Dict0}, Fs, ReqPkt);
+reply({MsgDict, Ans}, TPid, {AppDict, Dict0}, Fs, ReqPkt) ->
+    local(Ans, TPid, {MsgDict, AppDict, Dict0}, Fs, ReqPkt);
 
 %% ... or relayed.
-reply(#diameter_packet{} = Pkt, TPid, _Dict0, Fs, _ReqPkt) ->
+reply(#diameter_packet{} = Pkt, _TPid, {AppDict, Dict0}, Fs, _ReqPkt) ->
     eval_packet(Pkt, Fs),
-    send(TPid, Pkt).
+    {msg_dict(AppDict, Dict0, Pkt), Pkt}.
 
 %% local/5
 %%
@@ -700,14 +716,12 @@ local([Msg], TPid, DictT, Fs, ReqPkt)
        is_tuple(Msg) ->
     local(Msg, TPid, DictT, Fs, ReqPkt#diameter_packet{errors = []});
 
-local(Msg, TPid, {Dict, AppDict, Dict0} = DictT, Fs, ReqPkt) ->
-    Pkt = encode({Dict, AppDict},
+local(Msg, TPid, {MsgDict, AppDict, Dict0}, Fs, ReqPkt) ->
+    Pkt = encode({MsgDict, AppDict},
                  TPid,
-                 reset(make_answer_packet(Msg, ReqPkt), Dict, Dict0),
+                 reset(make_answer_packet(Msg, ReqPkt), MsgDict, Dict0),
                  Fs),
-    incr(send, Pkt, TPid, AppDict),
-    incr_rc(send, Pkt, TPid, DictT),  %% count outgoing
-    send(TPid, Pkt).
+    {MsgDict, Pkt}.
 
 %% reset/3
 
@@ -1067,54 +1081,75 @@ find_avp(Code, VId, [_ | Avps]) ->
 %% Increment a stats counter for result codes in incoming and outgoing
 %% answers.
 
+%% Message sent as a header/avps list.
+incr_result(send = Dir,
+            #diameter_packet{msg = [#diameter_header{} = H | _]}
+            = Pkt,
+            TPid,
+            DictT) ->
+    incr_res(Dir, Pkt#diameter_packet{header = H}, TPid, DictT);
+
 %% Outgoing message as binary: don't count. (Sending binaries is only
 %% partially supported.)
-incr_result(_, #diameter_packet{msg = undefined = No}, _, _) ->
+incr_result(send, #diameter_packet{header = undefined = No}, _, _) ->
     No;
 
 %% Incoming or outgoing. Outgoing with encode errors never gets here
 %% since encode fails.
-incr_result(Dir, Pkt, TPid, {Dict, AppDict, Dict0}) ->
-    #diameter_packet{header = #diameter_header{is_error = E}
-                            = Hdr,
-                     errors = Es}
-        = Pkt,
+incr_result(Dir, Pkt, TPid, DictT) ->
+    incr_res(Dir, Pkt, TPid, DictT).
+
+incr_res(Dir,
+         #diameter_packet{header = #diameter_header{is_error = E}
+                          = Hdr,
+                          errors = Es}
+         = Pkt,
+         TPid,
+         DictT) ->
+    {MsgDict, AppDict, Dict0} = DictT,
 
     Id = msg_id(Hdr, AppDict),
+    %% Could be {relay, 0}, in which case the R-bit is redundant since
+    %% only answers are being counted. Let it be however, so that the
+    %% same tuple is in both send/recv and result code counters.
 
     %% Count incoming decode errors.
     recv /= Dir orelse [] == Es orelse incr_error(Dir, Id, TPid, AppDict),
 
     %% Exit on a missing result code.
-    T = rc_counter(Dict, Dir, Pkt),
-    T == false andalso ?LOGX(no_result_code, {Dict, Dir, Hdr}),
+    T = rc_counter(MsgDict, Dir, Pkt),
+    T == false andalso ?LOGX(no_result_code, {MsgDict, Dir, Hdr}),
     {Ctr, RC, Avp} = T,
 
     %% Or on an inappropriate value.
     is_result(RC, E, Dict0)
-        orelse ?LOGX(invalid_error_bit, {Dict, Dir, Hdr, Avp}),
+        orelse ?LOGX(invalid_error_bit, {MsgDict, Dir, Hdr, Avp}),
 
     incr(TPid, {Id, Dir, Ctr}),
     Ctr.
 
 %% msg_id/2
 
-msg_id(#diameter_packet{header = H}, Dict) ->
-    msg_id(H, Dict);
+msg_id(#diameter_packet{header = H}, AppDict) ->
+    msg_id(H, AppDict);
 
 %% Only count on known keys so as not to be vulnerable to attack:
 %% there are 2^32 (application ids) * 2^24 (command codes) = 2^56
 %% pairs for an attacker to choose from.
-msg_id(Hdr, Dict) ->
+msg_id(Hdr, AppDict) ->
     {Aid, Code, R} = Id = diameter_codec:msg_id(Hdr),
-    if Aid == ?APP_ID_RELAY ->
+    case AppDict:id() of
+        ?APP_ID_RELAY ->
             {relay, R};
-       true ->
-            choose(Aid /= Dict:id() orelse '' == Dict:msg_name(Code, 0 == R),
-                   unknown,
-                   Id)
+        A ->
+            unknown(A /= Aid orelse '' == AppDict:msg_name(Code, 0 == R), Id)
     end.
 
+unknown(true, {_, _, R}) ->
+    {unknown, R};
+unknown(false, Id) ->
+    Id.
+
 %% No E-bit: can't be 3xxx.
 is_result(RC, false, _Dict0) ->
     RC < 3000 orelse 4000 =< RC;
@@ -1142,7 +1177,11 @@ incr(TPid, Counter) ->
 %%   applications MUST include either one Result-Code AVP or one
 %%   Experimental-Result AVP.
 
-rc_counter(Dict, recv, #diameter_packet{header = H, avps = As}) ->
+rc_counter(Dict, Dir, #diameter_packet{header = H,
+                                       avps = As,
+                                       msg = Msg})
+  when Dir == recv;         %% decoded incoming
+       Msg == undefined ->  %% relayed outgoing
     rc_counter(Dict, [H|As]);
 
 rc_counter(Dict, _, #diameter_packet{msg = Msg}) ->
@@ -1434,12 +1473,12 @@ fold_record(Rec, R) ->
 %% send_R/6
 
 send_R(Pkt0,
-       {TPid, Caps, #diameter_app{dictionary = Dict} = App},
+       {TPid, Caps, #diameter_app{dictionary = AppDict} = App},
        Opts,
        {Pid, Ref},
        SvcName,
        Fs) ->
-    Pkt = encode(Dict, TPid, Pkt0, Fs),
+    Pkt = encode(AppDict, TPid, Pkt0, Fs),
 
     #options{timeout = Timeout}
         = Opts,
@@ -1452,7 +1491,7 @@ send_R(Pkt0,
                    packet = Pkt0},
 
     try
-        incr(send, Pkt, TPid, Dict),
+        incr(send, Pkt, TPid, AppDict),
         TRef = send_request(TPid, Pkt, Req, SvcName, Timeout),
         Pid ! Ref,  %% tell caller a send has been attempted
         handle_answer(SvcName,
@@ -1492,10 +1531,10 @@ handle_answer(SvcName,
                             id = Id}
               = App,
               {answer, Req, Dict0, Pkt}) ->
-    Dict = dict(AppDict, Dict0, Pkt),
-    handle_A(errors(Id, diameter_codec:decode({Dict, AppDict}, Pkt)),
+    MsgDict = msg_dict(AppDict, Dict0, Pkt),
+    handle_A(errors(Id, diameter_codec:decode({MsgDict, AppDict}, Pkt)),
              SvcName,
-             Dict,
+             MsgDict,
              Dict0,
              App,
              Req).
@@ -1765,19 +1804,19 @@ retransmit(T, {_, _, App}, _, _, _, _) ->
     ?ERROR({invalid_return, T, prepare_retransmit, App}).
 
 resend_request(Pkt0,
-               {TPid, Caps, #diameter_app{dictionary = Dict}},
+               {TPid, Caps, #diameter_app{dictionary = AppDict}},
                Req0,
                SvcName,
                Tmo,
                Fs) ->
-    Pkt = encode(Dict, TPid, Pkt0, Fs),
+    Pkt = encode(AppDict, TPid, Pkt0, Fs),
 
     Req = Req0#request{transport = TPid,
                        packet = Pkt0,
                        caps = Caps},
 
     ?LOG(retransmission, Pkt#diameter_packet.header),
-    incr(TPid, {msg_id(Pkt, Dict), send, retransmission}),
+    incr(TPid, {msg_id(Pkt, AppDict), send, retransmission}),
     TRef = send_request(TPid, Pkt, Req, SvcName, Tmo),
     {TRef, Req}.
 
@@ -1887,7 +1926,7 @@ get_avp(Dict, Name, [#diameter_header{} | Avps]) ->
         find_avp(Code, VId, Avps)
     of
         A ->
-            avp_decode(Dict, Name, ungroup(A))
+            (avp_decode(Dict, Name, ungroup(A)))#diameter_avp{name = Name}
     catch
         error: _ ->
             undefined
diff --git a/lib/diameter/src/diameter.appup.src b/lib/diameter/src/diameter.appup.src
index 0ef0fd35a9..b89859ed24 100644
--- a/lib/diameter/src/diameter.appup.src
+++ b/lib/diameter/src/diameter.appup.src
@@ -65,11 +65,14 @@
                {update, diameter_sup, supervisor}]},
   {"1.9",     [{load_module, diameter_codec},      %% 17.5
                {load_module, diameter_traffic},
+               {load_module, diameter_sctp},
                {load_module, diameter_gen_base_rfc6733},
                {load_module, diameter_gen_acct_rfc6733},
                {load_module, diameter_gen_base_rfc3588},
                {load_module, diameter_gen_base_accounting},
-               {load_module, diameter_gen_relay}]}
+               {load_module, diameter_gen_relay}]},
+  {"1.9.1",   [{load_module, diameter_traffic},    %% 17.5.3
+               {load_module, diameter_sctp}]}
  ],
  [
   {"0.9",     [{restart_application, diameter}]},
@@ -120,7 +123,10 @@
                {load_module, diameter_gen_base_rfc3588},
                {load_module, diameter_gen_acct_rfc6733},
                {load_module, diameter_gen_base_rfc6733},
+               {load_module, diameter_sctp},
                {load_module, diameter_traffic},
-               {load_module, diameter_codec}]}
+               {load_module, diameter_codec}]},
+  {"1.9.1",   [{load_module, diameter_sctp},
+               {load_module, diameter_traffic}]}
  ]
 }.
diff --git a/lib/diameter/src/transport/diameter_sctp.erl b/lib/diameter/src/transport/diameter_sctp.erl
index 2c8d6f0a14..f80de0a816 100644
--- a/lib/diameter/src/transport/diameter_sctp.erl
+++ b/lib/diameter/src/transport/diameter_sctp.erl
@@ -223,9 +223,9 @@ init(T) ->
 i({listen, Ref, {Opts, Addrs}}) ->
     {[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}}),
+    proc_lib:init_ack({ok, self(), LAs}),
     start_timer(#listener{ref = Ref,
                           socket = Sock,
                           accept = accept(Matches)});
diff --git a/lib/diameter/test/diameter_3xxx_SUITE.erl b/lib/diameter/test/diameter_3xxx_SUITE.erl
index 44fc3a60aa..44cb0cc484 100644
--- a/lib/diameter/test/diameter_3xxx_SUITE.erl
+++ b/lib/diameter/test/diameter_3xxx_SUITE.erl
@@ -195,13 +195,13 @@ counters(_, _, _, _) ->
 stats(?CLIENT, E, rfc3588, L)
   when E == answer;
        E == answer_3xxx ->
-    [{{unknown,recv},2},
+    [{{{unknown,0},recv},2},
      {{{0,257,0},recv},1},
      {{{0,257,1},send},1},
      {{{0,275,0},recv},6},
      {{{0,275,1},send},10},
-     {{unknown,recv,{'Result-Code',3001}},1},
-     {{unknown,recv,{'Result-Code',3007}},1},
+     {{{unknown,0},recv,{'Result-Code',3001}},1},
+     {{{unknown,0},recv,{'Result-Code',3007}},1},
      {{{0,257,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',3008}},2},
@@ -213,15 +213,15 @@ stats(?CLIENT, E, rfc3588, L)
 stats(?SERVER, E, rfc3588, L)
   when E == answer;
        E == answer_3xxx ->
-    [{{unknown,recv},1},
-     {{unknown,send},2},
+    [{{{unknown,0},send},2},
+     {{{unknown,1},recv},1},
      {{{0,257,0},send},1},
      {{{0,257,1},recv},1},
      {{{0,275,0},send},6},
      {{{0,275,1},recv},8},
-     {{unknown,recv,error},1},
-     {{unknown,send,{'Result-Code',3001}},1},
-     {{unknown,send,{'Result-Code',3007}},1},
+     {{{unknown,0},send,{'Result-Code',3001}},1},
+     {{{unknown,0},send,{'Result-Code',3007}},1},
+     {{{unknown,1},recv,error},1},
      {{{0,257,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',3008}},2},
@@ -232,13 +232,13 @@ stats(?SERVER, E, rfc3588, L)
         = L;
 
 stats(?CLIENT, answer, rfc6733, L) ->
-    [{{unknown,recv},2},
+    [{{{unknown,0},recv},2},
      {{{0,257,0},recv},1},
      {{{0,257,1},send},1},
      {{{0,275,0},recv},8},
      {{{0,275,1},send},10},
-     {{unknown,recv,{'Result-Code',3001}},1},
-     {{unknown,recv,{'Result-Code',3007}},1},
+     {{{unknown,0},recv,{'Result-Code',3001}},1},
+     {{{unknown,0},recv,{'Result-Code',3007}},1},
      {{{0,257,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',3008}},2},
      {{{0,275,0},recv,{'Result-Code',3999}},1},
@@ -248,15 +248,15 @@ stats(?CLIENT, answer, rfc6733, L) ->
         = L;
 
 stats(?SERVER, answer, rfc6733, L) ->
-    [{{unknown,recv},1},
-     {{unknown,send},2},
+    [{{{unknown,0},send},2},
+     {{{unknown,1},recv},1},
      {{{0,257,0},send},1},
      {{{0,257,1},recv},1},
      {{{0,275,0},send},8},
      {{{0,275,1},recv},8},
-     {{unknown,recv,error},1},
-     {{unknown,send,{'Result-Code',3001}},1},
-     {{unknown,send,{'Result-Code',3007}},1},
+     {{{unknown,0},send,{'Result-Code',3001}},1},
+     {{{unknown,0},send,{'Result-Code',3007}},1},
+     {{{unknown,1},recv,error},1},
      {{{0,257,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',3008}},2},
      {{{0,275,0},send,{'Result-Code',3999}},1},
@@ -267,13 +267,13 @@ stats(?SERVER, answer, rfc6733, L) ->
         = L;
 
 stats(?CLIENT, answer_3xxx, rfc6733, L) ->
-    [{{unknown,recv},2},
+    [{{{unknown,0},recv},2},
      {{{0,257,0},recv},1},
      {{{0,257,1},send},1},
      {{{0,275,0},recv},8},
      {{{0,275,1},send},10},
-     {{unknown,recv,{'Result-Code',3001}},1},
-     {{unknown,recv,{'Result-Code',3007}},1},
+     {{{unknown,0},recv,{'Result-Code',3001}},1},
+     {{{unknown,0},recv,{'Result-Code',3007}},1},
      {{{0,257,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',3008}},2},
@@ -284,15 +284,15 @@ stats(?CLIENT, answer_3xxx, rfc6733, L) ->
         = L;
 
 stats(?SERVER, answer_3xxx, rfc6733, L) ->
-    [{{unknown,recv},1},
-     {{unknown,send},2},
+    [{{{unknown,0},send},2},
+     {{{unknown,1},recv},1},
      {{{0,257,0},send},1},
      {{{0,257,1},recv},1},
      {{{0,275,0},send},8},
      {{{0,275,1},recv},8},
-     {{unknown,recv,error},1},
-     {{unknown,send,{'Result-Code',3001}},1},
-     {{unknown,send,{'Result-Code',3007}},1},
+     {{{unknown,0},send,{'Result-Code',3001}},1},
+     {{{unknown,0},send,{'Result-Code',3007}},1},
+     {{{unknown,1},recv,error},1},
      {{{0,257,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',3008}},2},
@@ -304,12 +304,12 @@ stats(?SERVER, answer_3xxx, rfc6733, L) ->
         = L;
 
 stats(?CLIENT, callback, rfc3588, L) ->
-    [{{unknown,recv},1},
+    [{{{unknown,0},recv},1},
      {{{0,257,0},recv},1},
      {{{0,257,1},send},1},
      {{{0,275,0},recv},6},
      {{{0,275,1},send},10},
-     {{unknown,recv,{'Result-Code',3007}},1},
+     {{{unknown,0},recv,{'Result-Code',3007}},1},
      {{{0,257,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',2001}},2},
      {{{0,275,0},recv,{'Result-Code',3999}},1},
@@ -318,14 +318,14 @@ stats(?CLIENT, callback, rfc3588, L) ->
         = L;
 
 stats(?SERVER, callback, rfc3588, L) ->
-    [{{unknown,recv},1},
-     {{unknown,send},1},
+    [{{{unknown,0},send},1},
+     {{{unknown,1},recv},1},
      {{{0,257,0},send},1},
      {{{0,257,1},recv},1},
      {{{0,275,0},send},6},
      {{{0,275,1},recv},8},
-     {{unknown,recv,error},1},
-     {{unknown,send,{'Result-Code',3007}},1},
+     {{{unknown,0},send,{'Result-Code',3007}},1},
+     {{{unknown,1},recv,error},1},
      {{{0,257,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',2001}},2},
      {{{0,275,0},send,{'Result-Code',3999}},1},
@@ -335,12 +335,12 @@ stats(?SERVER, callback, rfc3588, L) ->
         = L;
 
 stats(?CLIENT, callback, rfc6733, L) ->
-    [{{unknown,recv},1},
+    [{{{unknown,0},recv},1},
      {{{0,257,0},recv},1},
      {{{0,257,1},send},1},
      {{{0,275,0},recv},8},
      {{{0,275,1},send},10},
-     {{unknown,recv,{'Result-Code',3007}},1},
+     {{{unknown,0},recv,{'Result-Code',3007}},1},
      {{{0,257,0},recv,{'Result-Code',2001}},1},
      {{{0,275,0},recv,{'Result-Code',2001}},2},
      {{{0,275,0},recv,{'Result-Code',3999}},1},
@@ -350,14 +350,14 @@ stats(?CLIENT, callback, rfc6733, L) ->
         = L;
 
 stats(?SERVER, callback, rfc6733, L) ->
-    [{{unknown,recv},1},
-     {{unknown,send},1},
+    [{{{unknown,0},send},1},
+     {{{unknown,1},recv},1},
      {{{0,257,0},send},1},
      {{{0,257,1},recv},1},
      {{{0,275,0},send},8},
      {{{0,275,1},recv},8},
-     {{unknown,recv,error},1},
-     {{unknown,send,{'Result-Code',3007}},1},
+     {{{unknown,0},send,{'Result-Code',3007}},1},
+     {{{unknown,1},recv,error},1},
      {{{0,257,0},send,{'Result-Code',2001}},1},
      {{{0,275,0},send,{'Result-Code',2001}},2},
      {{{0,275,0},send,{'Result-Code',3999}},1},
diff --git a/lib/diameter/test/diameter_config_SUITE.erl b/lib/diameter/test/diameter_config_SUITE.erl
index bbdf672291..4bcaa8119f 100644
--- a/lib/diameter/test/diameter_config_SUITE.erl
+++ b/lib/diameter/test/diameter_config_SUITE.erl
@@ -50,7 +50,7 @@
                 {request_errors, RE},
                 {call_mutates_state, C}]]
               || D <- [diameter_gen_base_rfc3588, diameter_gen_base_rfc6733],
-                 M <- [?MODULE, [?MODULE, now()]],
+                 M <- [?MODULE, [?MODULE, diameter_lib:now()]],
                  A <- [0, common, make_ref()],
                  S <- [[], make_ref()],
                  AE <- [report, callback, discard],
diff --git a/lib/diameter/test/diameter_relay_SUITE.erl b/lib/diameter/test/diameter_relay_SUITE.erl
index 735a908d97..7142239bbb 100644
--- a/lib/diameter/test/diameter_relay_SUITE.erl
+++ b/lib/diameter/test/diameter_relay_SUITE.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2010-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2010-2015. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -49,6 +49,7 @@
          send_timeout_1/1,
          send_timeout_2/1,
          info/1,
+         counters/1,
          disconnect/1,
          stop_services/1,
          stop/1]).
@@ -120,6 +121,7 @@ all() ->
      start_services,
      connect,
      {group, all},
+     counters,
      {group, all, [parallel]},
      disconnect,
      stop_services,
@@ -201,8 +203,8 @@ send3(_Config) ->
 send4(_Config) ->
     call(?SERVER4).
 
-%% Send an ASR that loops between the relays and expect the loop to
-%% be detected.
+%% Send an ASR that loops between the relays (RELAY1 -> RELAY2 ->
+%% RELAY1) and expect the loop to be detected.
 send_loop(_Config) ->
     Req = ['ASR', {'Destination-Realm', realm(?SERVER1)},
                   {'Destination-Host', ?SERVER1},
@@ -227,8 +229,103 @@ send_timeout(Tmo) ->
     call(Req, [{filter, realm}, {timeout, Tmo}]).
 
 info(_Config) ->
+    %% Wait for RELAY1 to have answered all requests, so that the
+    %% suite doesn't end before all answers are sent and counted.
+    receive after 6000 -> ok end,
     [] = ?util:info().
 
+counters(_Config) ->
+    [] = ?util:run([[fun counters/2, K, S]
+                    || K <- [statistics, transport, connections],
+                       S <- ?SERVICES]).
+
+counters(Key, Svc) ->
+    counters(Key, Svc, [_|_] = diameter:service_info(Svc, Key)).
+
+counters(statistics, Svc, Stats) ->
+    stats(Svc, lists:foldl(fun({K,N},D) -> orddict:update_counter(K, N, D) end,
+                           orddict:new(),
+                           lists:append([L || {P,L} <- Stats, is_pid(P)])));
+
+counters(_, _, _) ->
+    todo.
+
+stats(?CLIENT, L) ->
+    [{{{0,257,0},recv},2},   %% CEA
+     {{{0,257,1},send},2},   %% CER
+     {{{0,258,0},recv},1},   %% RAA (send_timeout_1)
+     {{{0,258,1},send},2},   %% RAR (send_timeout_[12])
+     {{{0,274,0},recv},1},   %% ASA (send_loop)
+     {{{0,274,1},send},1},   %% ASR (send_loop)
+     {{{0,275,0},recv},4},   %% STA (send[1-4])
+     {{{0,275,1},send},4},   %% STR (send[1-4])
+     {{{unknown,0},recv,discarded},1},  %% RAR (send_timeout_2)
+     {{{0,257,0},recv,{'Result-Code',2001}},2},  %% CEA
+     {{{0,258,0},recv,{'Result-Code',3002}},1},  %% RAA (send_timeout_1)
+     {{{0,274,0},recv,{'Result-Code',3005}},1},  %% ASA (send_loop)
+     {{{0,275,0},recv,{'Result-Code',2001}},4}]  %% STA (send[1-4])
+        = L;
+
+stats(S, L)
+  when S == ?SERVER1;
+       S == ?SERVER2;
+       S == ?SERVER3;
+       S == ?SERVER4 ->
+    [{{{0,257,0},send},1},   %% CEA
+     {{{0,257,1},recv},1},   %% CER
+     {{{0,275,0},send},1},   %% STA (send[1-4])
+     {{{0,275,1},recv},1},   %% STR (send[1-4])
+     {{{0,257,0},send,{'Result-Code',2001}},1},  %% CEA
+     {{{0,275,0},send,{'Result-Code',2001}},1}]  %% STA (send[1-4])
+        = L;
+
+stats(?RELAY1, L) ->
+    [{{{relay,0},recv},3},   %% STA x 2 (send[12])
+                             %% ASA     (send_loop)
+     {{{relay,0},send},6},   %% STA x 2 (send[12])
+                             %% ASA x 2 (send_loop)
+                             %% RAA x 2 (send_timeout_[12])
+     {{{relay,1},recv},6},   %% STR x 2 (send[12])
+                             %% ASR x 2 (send_loop)
+                             %% RAR x 2 (send_timeout_[12])
+     {{{relay,1},send},5},   %% STR x 2 (send[12])
+                             %% ASR     (send_loop)
+                             %% RAR x 2 (send_timeout_[12])
+     {{{0,257,0},recv},3},   %% CEA
+     {{{0,257,0},send},1},   %%  "
+     {{{0,257,1},recv},1},   %% CER 
+     {{{0,257,1},send},3},   %%  "
+     {{{relay,0},recv,{'Result-Code',2001}},2},  %% STA x 2 (send[34])
+     {{{relay,0},recv,{'Result-Code',3005}},1},  %% ASA     (send_loop)
+     {{{relay,0},send,{'Result-Code',2001}},2},  %% STA x 2 (send[34])
+     {{{relay,0},send,{'Result-Code',3002}},2},  %% RAA     (send_timeout_[12])
+     {{{relay,0},send,{'Result-Code',3005}},2},  %% ASA     (send_loop)
+     {{{0,257,0},recv,{'Result-Code',2001}},3},  %% CEA
+     {{{0,257,0},send,{'Result-Code',2001}},1}]  %%  "
+        = L;
+
+stats(?RELAY2, L) ->
+    [{{{relay,0},recv},3},   %% STA x 2 (send[34])
+                             %% ASA     (send_loop)
+     {{{relay,0},send},3},   %% STA x 2 (send[34])
+                             %% ASA     (send_loop)
+     {{{relay,1},recv},5},   %% STR x 2 (send[34])
+                             %% RAR x 2 (send_timeout_[12])
+                             %% ASR     (send_loop)
+     {{{relay,1},send},3},   %% STR x 2 (send[34])
+                             %% ASR     (send_loop)
+     {{{0,257,0},recv},2},   %% CEA
+     {{{0,257,0},send},2},   %%  "
+     {{{0,257,1},recv},2},   %% CER
+     {{{0,257,1},send},2},   %%  "
+     {{{relay,0},recv,{'Result-Code',2001}},2},  %% STA x 2 (send[34])
+     {{{relay,0},recv,{'Result-Code',3005}},1},  %% ASA     (send_loop)
+     {{{relay,0},send,{'Result-Code',2001}},2},  %% STA x 2 (send[34])
+     {{{relay,0},send,{'Result-Code',3005}},1},  %% ASA     (send_loop)
+     {{{0,257,0},recv,{'Result-Code',2001}},2},  %% CEA
+     {{{0,257,0},send,{'Result-Code',2001}},2}]  %%  "
+        = L.
+
 %% ===========================================================================
 
 realm(Host) ->
@@ -303,18 +400,24 @@ handle_request(Pkt, OH, {_Ref, #diameter_caps{origin_host = {OH,_}} = Caps})
   when OH /= ?CLIENT ->
     request(Pkt, Caps).
 
-%% RELAY1 routes any ASR or RAR to RELAY2 ...
+%% RELAY1 answers ACR after it's timed out at the client.
+request(#diameter_packet{header = #diameter_header{cmd_code = 271}},
+        #diameter_caps{origin_host = {?RELAY1, _}}) ->
+    receive after 1000 -> {answer_message, 3004} end;  %% TOO_BUSY
+
+%% RELAY1 routes any ASR or RAR to RELAY2.
 request(#diameter_packet{header = #diameter_header{cmd_code = C}},
         #diameter_caps{origin_host = {?RELAY1, _}})
   when C == 274;   %% ASR
        C == 258 -> %% RAR
     {relay, [{filter, {realm, realm(?RELAY2)}}]};
 
-%% ... which in turn routes it back. Expect diameter to either answer
-%% either with DIAMETER_LOOP_DETECTED/DIAMETER_UNABLE_TO_COMPLY.
+%% RELAY2 routes ASR back to RELAY1 to induce DIAMETER_LOOP_DETECTED.
 request(#diameter_packet{header = #diameter_header{cmd_code = 274}},
         #diameter_caps{origin_host = {?RELAY2, _}}) ->
     {relay, [{filter, {host, ?RELAY1}}]};
+
+%% RELAY2 discards RAR to induce DIAMETER_UNABLE_TO_DELIVER.
 request(#diameter_packet{header = #diameter_header{cmd_code = 258}},
         #diameter_caps{origin_host = {?RELAY2, _}}) ->
     discard;
diff --git a/lib/diameter/test/diameter_tls_SUITE.erl b/lib/diameter/test/diameter_tls_SUITE.erl
index 55565692ec..e5bbda9c91 100644
--- a/lib/diameter/test/diameter_tls_SUITE.erl
+++ b/lib/diameter/test/diameter_tls_SUITE.erl
@@ -319,19 +319,19 @@ make_cert(Dir, Base) ->
     make_cert(Dir, Base ++ "_key.pem", Base ++ "_ca.pem").
 
 make_cert(Dir, Keyfile, Certfile) ->
-    [K,C] = Paths = [filename:join([Dir, F]) || F <- [Keyfile, Certfile]],
+    [KP,CP] = [filename:join([Dir, F]) || F <- [Keyfile, Certfile]],
 
-    KCmd = join(["openssl genrsa -out", K, "2048"]),
-    CCmd = join(["openssl req -new -x509 -key", K, "-out", C, "-days 7",
-                 "-subj /C=SE/ST=./L=Stockholm/CN=www.erlang.org"]),
+    KC = join(["openssl genrsa -out", KP, "2048"]),
+    CC = join(["openssl req -new -x509 -key", KP, "-out", CP, "-days 7",
+               "-subj /C=SE/ST=./L=Stockholm/CN=www.erlang.org"]),
 
     %% Hope for the best and only check that files are written.
-    os:cmd(KCmd),
-    os:cmd(CCmd),
+    [{_, _, {ok,_}},{_, _, {ok,_}}]
+        = [{P,O,T} || {P,C} <- [{KP,KC}, {CP,CC}],
+                      O <- [os:cmd(C)],
+                      T <- [file:read_file_info(P)]],
 
-    [_,_] = [T || P <- Paths, {ok, T} <- [file:read_file_info(P)]],
-
-    {K,C}.
+    {KP,CP}.
 
 join(Strs) ->
     string:join(Strs, " ").
diff --git a/lib/diameter/test/diameter_traffic_SUITE.erl b/lib/diameter/test/diameter_traffic_SUITE.erl
index 7ff6ba7ab9..17faf30a9b 100644
--- a/lib/diameter/test/diameter_traffic_SUITE.erl
+++ b/lib/diameter/test/diameter_traffic_SUITE.erl
@@ -145,8 +145,12 @@
 %% them as binary.
 -define(STRING_DECODES, [true, false]).
 
+%% Which transport protocol to use.
+-define(TRANSPORTS, [tcp, sctp]).
+
 -record(group,
-        {client_service,
+        {transport,
+         client_service,
          client_encoding,
          client_dict0,
          client_strings,
@@ -234,19 +238,20 @@
 %% ===========================================================================
 
 suite() ->
-    [{timetrap, {seconds, 60}}].
+    [{timetrap, {seconds, 10}}].
 
 all() ->
     [start, result_codes, {group, traffic}, outstanding, empty, stop].
 
 groups() ->
     Ts = tc(),
+    Sctp = ?util:have_sctp(),
     [{?util:name([R,D,A,C]), [parallel], Ts} || R <- ?ENCODINGS,
                                                 D <- ?RFCS,
                                                 A <- ?ENCODINGS,
                                                 C <- ?CONTAINERS]
         ++
-        [{?util:name([R,D,A,C,SD,CD]),
+        [{?util:name([T,R,D,A,C,SD,CD]),
           [],
           [start_services,
            add_transports,
@@ -254,15 +259,19 @@ groups() ->
            {group, ?util:name([R,D,A,C])},
            remove_transports,
            stop_services]}
-         || R <- ?ENCODINGS,
+         || T <- ?TRANSPORTS,
+            T /= sctp orelse Sctp,
+            R <- ?ENCODINGS,
             D <- ?RFCS,
             A <- ?ENCODINGS,
             C <- ?CONTAINERS,
             SD <- ?STRING_DECODES,
             CD <- ?STRING_DECODES]
         ++
-        [{traffic, [parallel], [{group, ?util:name([R,D,A,C,SD,CD])}
-                                || R <- ?ENCODINGS,
+        [{traffic, [parallel], [{group, ?util:name([T,R,D,A,C,SD,CD])}
+                                || T <- ?TRANSPORTS,
+                                   T /= sctp orelse Sctp,
+                                   R <- ?ENCODINGS,
                                    D <- ?RFCS,
                                    A <- ?ENCODINGS,
                                    C <- ?CONTAINERS,
@@ -271,8 +280,9 @@ groups() ->
 
 init_per_group(Name, Config) ->
     case ?util:name(Name) of
-        [R,D,A,C,SD,CD] ->
-            G = #group{client_service = [$C|?util:unique_string()],
+        [T,R,D,A,C,SD,CD] ->
+            G = #group{transport = T,
+                       client_service = [$C|?util:unique_string()],
                        client_encoding = R,
                        client_dict0 = dict0(D),
                        client_strings = CD,
@@ -288,8 +298,18 @@ init_per_group(Name, Config) ->
 end_per_group(_, _) ->
     ok.
 
+%% Skip testcases that can reasonably fail under SCTP.
 init_per_testcase(Name, Config) ->
-    [{testcase, Name} | Config].
+    case [skip || #group{transport = sctp}
+                      <- [proplists:get_value(group, Config)],
+                  send_maxlen == Name
+                      orelse send_long == Name]
+    of
+        [skip] ->
+            {skip, sctp};
+        [] ->
+            [{testcase, Name} | Config]
+    end.
 
 end_per_testcase(_, _) ->
     ok.
@@ -367,16 +387,18 @@ start_services(Config) ->
                                      | ?SERVICE(CN, CD)]).
 
 add_transports(Config) ->
-    #group{client_service = CN,
+    #group{transport = T,
+           client_service = CN,
            server_service = SN}
         = group(Config), 
     LRef = ?util:listen(SN,
-                        tcp,
+                        T,
                         [{capabilities_cb, fun capx/2},
+                         {pool_size, 8},
                          {spawn_opt, [{min_heap_size, 8096}]},
                          {applications, apps(rfc3588)}]),
     Cs = [?util:connect(CN,
-                        tcp,
+                        T,
                         LRef,
                         [{id, Id},
                          {capabilities, [{'Origin-State-Id', origin(Id)}]},
diff --git a/lib/diameter/test/diameter_transport_SUITE.erl b/lib/diameter/test/diameter_transport_SUITE.erl
index f098851bea..78bddbd1cf 100644
--- a/lib/diameter/test/diameter_transport_SUITE.erl
+++ b/lib/diameter/test/diameter_transport_SUITE.erl
@@ -64,7 +64,7 @@
                                       = #diameter_caps{host_ip_address
                                                        = Addrs}}).
 
-%% The term we register after open a listening port with gen_tcp.
+%% The term we register after open a listening port with gen_{tcp,sctp}.
 -define(TEST_LISTENER(Ref, PortNr),
         {?MODULE, listen, Ref, PortNr}).
 
@@ -85,7 +85,7 @@
 %% ===========================================================================
 
 suite() ->
-    [{timetrap, {minutes, 2}}].
+    [{timetrap, {seconds, 15}}].
 
 all() ->
     [start,
@@ -401,12 +401,13 @@ gen_listen(tcp) ->
 %% gen_accept/2
 
 gen_accept(sctp, Sock) ->
-    Assoc = ?RECV(?SCTP(Sock, {_, #sctp_assoc_change{state = comm_up,
-                                                     outbound_streams = O,
-                                                     inbound_streams = I,
-                                                     assoc_id = A}}),
-                  {O, I, A}),
-    putr(assoc, Assoc),
+    #sctp_assoc_change{state = comm_up,
+                       outbound_streams = OS,
+                       inbound_streams = IS,
+                       assoc_id = Id}
+        = ?RECV(?SCTP(Sock, {_, #sctp_assoc_change{} = S}), S),
+
+    putr(assoc, {OS, IS, Id}),
     {ok, Sock};
 gen_accept(tcp, LSock) ->
     gen_tcp:accept(LSock).
diff --git a/lib/diameter/test/diameter_util.erl b/lib/diameter/test/diameter_util.erl
index c496876ee1..df7d268429 100644
--- a/lib/diameter/test/diameter_util.erl
+++ b/lib/diameter/test/diameter_util.erl
@@ -204,13 +204,14 @@ seed() ->
 %% unique_string/0
 
 unique_string() ->
-    us(diameter_lib:now()).
-
-us({M,S,U}) ->
-    tl(lists:append(["-" ++ integer_to_list(N) || N <- [M,S,U]]));
-
-us(MonoT) ->
-    integer_to_list(MonoT).
+    try erlang:unique_integer() of
+        N ->
+            integer_to_list(N)
+    catch
+        error: undef ->  %% OTP < 18
+            {M,S,U} = timestamp(),
+            tl(lists:append(["-" ++ integer_to_list(N) || N <- [M,S,U]]))
+    end.
 
 %% ---------------------------------------------------------------------------
 %% have_sctp/0
diff --git a/lib/diameter/test/diameter_watchdog_SUITE.erl b/lib/diameter/test/diameter_watchdog_SUITE.erl
index 5a3ff2c92f..f39e12686e 100644
--- a/lib/diameter/test/diameter_watchdog_SUITE.erl
+++ b/lib/diameter/test/diameter_watchdog_SUITE.erl
@@ -673,8 +673,7 @@ jitter(T,D) ->
 
 %% Generate a unique hostname for the faked peer.
 hostname() ->
-    {M,S,U} = diameter_util:timestamp(),
-    lists:flatten(io_lib:format("~p-~p-~p", [M,S,U])).
+    ?util:unique_string().
 
 putr(Key, Val) ->
     put({?MODULE, Key}, Val).
diff --git a/lib/diameter/vsn.mk b/lib/diameter/vsn.mk
index db7f72c44e..c278e74dca 100644
--- a/lib/diameter/vsn.mk
+++ b/lib/diameter/vsn.mk
@@ -16,5 +16,5 @@
 # %CopyrightEnd%
 
 APPLICATION  = diameter
-DIAMETER_VSN = 1.9.1
+DIAMETER_VSN = 1.9.2
 APP_VSN      = $(APPLICATION)-$(DIAMETER_VSN)$(PRE_VSN)