add {active,N} socket option for TCP, UDP, and SCTP

Add the {active,N} socket option, where N is an integer in the range
-32768..32767, to allow a caller to specify the number of data messages to
be delivered to the controlling process. Once the socket's delivered
message count either reaches 0 or is explicitly set to 0 with
inet:setopts/2 or by including {active,0} as an option when the socket is
created, the socket transitions to passive ({active, false}) mode and the
socket's controlling process receives a message to inform it of the
transition. TCP sockets receive {tcp_passive,Socket}, UDP sockets receive
{udp_passive,Socket} and SCTP sockets receive {sctp_passive,Socket}.

The socket's delivered message counter defaults to 0, but it can be set
using {active,N} via any gen_tcp, gen_udp, or gen_sctp function that takes
socket options as arguments, or via inet:setopts/2. New N values are added
to the socket's current counter value, and negative numbers can be used to
reduce the counter value. Specifying a number that would cause the socket's
counter value to go above 32767 causes an einval error. If a negative
number is specified such that the counter value would become negative, the
socket's counter value is set to 0 and the socket transitions to passive
mode. If the counter value is already 0 and inet:setopts(Socket,
[{active,0}]) is specified, the counter value remains at 0 but the
appropriate passive mode transition message is generated for the socket.

This commit contains a modified preloaded prim_inet.beam due to changes in
prim_inet.erl.

Add tests for {active,N} mode for TCP, UDP, and SCTP sockets.

Add documentation for {active,N} mode for inet, gen_tcp, gen_udp, and
gen_sctp.

12 files changed, 432 insertions, 39 deletions

diff --git a/lib/kernel/doc/src/gen_sctp.xml b/lib/kernel/doc/src/gen_sctp.xml
index dacea7a239..986260638d 100644
--- a/lib/kernel/doc/src/gen_sctp.xml
+++ b/lib/kernel/doc/src/gen_sctp.xml
@@ -496,9 +496,11 @@
       orthogonal to the sets of TCP, UDP and generic INET options:
       only those options which are explicitly listed below are allowed
       for SCTP sockets. Options can be set on the socket using
-      <c>gen_sctp:open/1,2</c> or <c>inet:setopts/2</c>,
-      retrieved using <c>inet:getopts/2</c>, and when calling
-      <c>gen_sctp:connect/4,5</c> options can be changed.</p>
+      <seealso marker="#open/1"><c>gen_sctp:open/1,2</c></seealso>
+      or <seealso marker="inet#setopts/2"><c>inet:setopts/2</c></seealso>,
+      retrieved using <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso>,
+      and when calling <seealso marker="#connect/4"><c>gen_sctp:connect/4,5</c></seealso>
+      options can be changed.</p>
     <marker id="option-binary"></marker>
     <marker id="option-list"></marker>
     <taglist>
@@ -507,7 +509,7 @@
         <p>Determines the type of data returned from <c>gen_sctp:recv/1,2</c>.</p>
         <marker id="option-active"></marker>
       </item>
-      <tag><c>{active, true|false|once}</c></tag>
+      <tag><c>{active, true|false|once|N}</c></tag>
       <item>
         <list type="bulleted">
           <item>
@@ -524,11 +526,28 @@
           </item>
           <item>
             <p>If <c>once</c>, only one message is automatically placed
-              in the message queue, after that the mode is automatically
-              re-set to passive. This provides flow control as well as
+              in the message queue, and after that the mode is automatically
+              reset to passive. This provides flow control as well as
               the possibility for the receiver to listen for its incoming
               SCTP data interleaved with other inter-process messages.</p>
           </item>
+          <item>
+            <p>If <c>active</c> is specified as an integer <c>N</c> in the
+              range -32768 to 32767 (inclusive), then that number is added to
+              the socket's count of the number of data messages to be
+              delivered to the controlling process. If the result of the
+              addition would be negative, the count is set to 0. Once the
+              count reaches 0, either through the delivery of messages or by
+              being explicitly set with <seealso
+              marker="inet#setopts/2">inet:setopts/2</seealso>, the socket's
+              mode is automatically reset to passive (<c>{active,
+              false}</c>) mode. When a socket in this active mode transitions to
+              passive mode, the message <c>{sctp_passive, Socket}</c> is sent
+              to the controlling process to notify it that if it wants to
+              receive more data messages from the socket, it must call
+              <seealso marker="inet#setopts/2">inet:setopts/2</seealso> to set
+              the socket back into an active mode.</p>
+          </item>
         </list>
       </item>
      <tag><c>{tos, integer()}</c></tag>
diff --git a/lib/kernel/doc/src/gen_tcp.xml b/lib/kernel/doc/src/gen_tcp.xml
index 7afd73f4bf..dbd0d3c815 100644
--- a/lib/kernel/doc/src/gen_tcp.xml
+++ b/lib/kernel/doc/src/gen_tcp.xml
@@ -148,6 +148,12 @@ do_recv(Sock, Bs) ->
           as messages:</p>
         <code type="none">
 {tcp, Socket, Data}</code>
+        <p>If the socket is in <c>{active, N}</c> mode (see <seealso marker="inet#setopts/2">
+          inet:setopts/2</seealso> for details) and its message counter
+          drops to 0, the following message is delivered to indicate that the
+          socket has transitioned to passive (<c>{active, false}</c>) mode:</p>
+        <code type="none">
+{tcp_passive, Socket}</code>
         <p>If the socket is closed, the following message is delivered:</p>
         <code type="none">
 {tcp_closed, Socket}</code>
diff --git a/lib/kernel/doc/src/gen_udp.xml b/lib/kernel/doc/src/gen_udp.xml
index faca31e928..503725fe18 100644
--- a/lib/kernel/doc/src/gen_udp.xml
+++ b/lib/kernel/doc/src/gen_udp.xml
@@ -145,14 +145,23 @@
               <seealso marker="inet#setopts/2">inet:setopts/2</seealso>.</p>
           </item>
         </taglist>
-        <p>The returned socket <c><anno>Socket</anno></c> is used to send packets
-          from this port with <c>send/4</c>. When UDP packets arrive at
-          the opened port, they are delivered as messages:</p>
+        <p>The returned socket <c><anno>Socket</anno></c> is used to send
+          packets from this port with <c>send/4</c>. When UDP packets arrive
+          at the opened port, if the socket is in an active mode the packets
+          are delivered as messages to the controlling process:</p>
         <code type="none">
 {udp, Socket, IP, InPortNo, Packet}</code>
-        <p>Note that arriving UDP packets that are longer than
+        <p>If the socket is not in an active mode, data can be
+          retrieved via the <seealso marker="#recv/2">recv/2,3</seealso> calls.
+          Note that arriving UDP packets that are longer than
           the receive buffer option specifies, might be truncated
           without warning.</p>
+        <p>When a socket in <c>{active, N}</c> mode (see <seealso marker="inet#setopts/2">
+          inet:setopts/2</seealso> for details) transitions to passive
+          (<c>{active, false}</c>) mode, the controlling process is notified by a
+          message of the following form:</p>
+        <code type="none">
+{udp_passive, Socket}</code>
         <p><c>IP</c> and <c>InPortNo</c> define the address from which
           <c>Packet</c> came. <c>Packet</c> is a list of bytes if
           the option <c>list</c> was specified. <c>Packet</c> is a
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml
index e1b0b34888..fb8bf32978 100644
--- a/lib/kernel/doc/src/inet.xml
+++ b/lib/kernel/doc/src/inet.xml
@@ -456,47 +456,66 @@ fe80::204:acff:fe17:bf38
         <p>Sets one or more options for a socket. The following options
           are available:</p>
         <taglist>
-          <tag><c>{active, true | false | once}</c></tag>
+          <tag><c>{active, true | false | once | N}</c></tag>
           <item>
             <p>If the value is <c>true</c>, which is the default,
               everything received from the socket will be sent as
               messages to the receiving process. If the value is
               <c>false</c> (passive mode), the process must explicitly
-              receive incoming data by calling <c>gen_tcp:recv/2,3</c>
-              or <c>gen_udp:recv/2,3</c> (depending on the type of
-              socket).</p>
+              receive incoming data by calling
+              <seealso marker="gen_tcp#recv/2"><c>gen_tcp:recv/2,3</c></seealso>,
+              <seealso marker="gen_udp#recv/2"><c>gen_udp:recv/2,3</c></seealso>
+              or <seealso marker="gen_sctp#recv/1"><c>gen_sctp:recv/1,2</c></seealso>
+              (depending on the type of socket).</p>
             <p>If the value is <c>once</c> (<c>{active, once}</c>),
               <em>one</em> data message from the socket will be sent
               to the process.  To receive one more message,
               <c>setopts/2</c> must be called again with the
               <c>{active, once}</c> option.</p>
-            <p>When using <c>{active, once}</c>, the socket changes
-              behaviour automatically when data is received. This can
-              sometimes be confusing in combination with connection
-              oriented sockets (i.e. <c>gen_tcp</c>) as a socket with
-              <c>{active, false}</c> behaviour reports closing
+            <p>If the value is an integer <c>N</c> in the range -32768 to 32767
+              (inclusive), the value is added to the socket's count of data
+              messages sent to the controlling process. A socket's default
+              message count is 0. If a negative value is specified and its
+              magnitude is equal to or greater than the socket's current
+              message count, the socket's message count is set to 0. Once
+              the socket's message count reaches 0, either due to sending
+              received data messages to the process or by being explicitly set,
+              the process is then notified by a special message, specific to
+              the type of socket, that the socket has entered passive
+              mode. Once the socket enters passive mode, to receive more
+              messages <c>setopts/2</c> must be called again to set the
+              socket back into an active mode.</p>
+            <p>When using <c>{active, once}</c> or <c>{active, N}</c>, the
+              socket changes behaviour automatically when data is received.
+              This can sometimes be confusing in combination with
+              connection-oriented sockets (i.e. <c>gen_tcp</c>) as a socket
+              with <c>{active, false}</c> behaviour reports closing
               differently than a socket with <c>{active, true}</c>
               behaviour. To make programming easier, a socket where
               the peer closed and this was detected while in
               <c>{active, false}</c> mode, will still generate the
               message
-              <c>{tcp_closed,Socket}</c> when set to <c>{active, once}</c> or <c>{active, true}</c> mode. It is therefore
+              <c>{tcp_closed,Socket}</c> when set to <c>{active, once}</c>,
+              <c>{active, true}</c> or <c>{active, N}</c> mode. It is therefore
               safe to assume that the message
               <c>{tcp_closed,Socket}</c>, possibly followed by socket
               port termination (depending on the <c>exit_on_close</c>
               option) will eventually appear when a socket changes
               back and forth between <c>{active, true}</c> and
-              <c>{active, false}</c> mode. However, 
+              <c>{active, false}</c> mode. However,
               <em>when</em> peer closing is detected is all up to the
               underlying TCP/IP stack and protocol.</p>
-            <p>Note that <c>{active,true}</c> mode provides no flow
+            <p>Note that <c>{active, true}</c> mode provides no flow
               control; a fast sender could easily overflow the
-              receiver with incoming messages. Use active mode only if
+              receiver with incoming messages. The same is true of
+              <c>{active, N}</c> mode while the message count is greater
+              than zero. Use active mode only if
               your high-level protocol provides its own flow control
               (for instance, acknowledging received messages) or the
-              amount of data exchanged is small. <c>{active,false}</c>
-              mode or use of the <c>{active, once}</c> mode provides
-              flow control; the other side will not be able send
+              amount of data exchanged is small. <c>{active, false}</c>
+              mode, use of the <c>{active, once}</c> mode or <c>{active, N}</c>
+              mode with values of <c>N</c> appropriate for the application
+              provides flow control; the other side will not be able send
               faster than the receiver can read.</p>
           </item>
 
diff --git a/lib/kernel/src/gen_sctp.erl b/lib/kernel/src/gen_sctp.erl
index 0d005eb651..23a698f9b2 100644
--- a/lib/kernel/src/gen_sctp.erl
+++ b/lib/kernel/src/gen_sctp.erl
@@ -36,7 +36,7 @@
 
 -type assoc_id() :: term().
 -type option() ::
-        {active, true | false | once} |
+        {active, true | false | once | -32768..32767} |
         {buffer, non_neg_integer()} |
         {dontroute, boolean()} |
         {high_msgq_watermark, pos_integer()} |
diff --git a/lib/kernel/src/gen_tcp.erl b/lib/kernel/src/gen_tcp.erl
index 96026aa428..bc8ffbe5e3 100644
--- a/lib/kernel/src/gen_tcp.erl
+++ b/lib/kernel/src/gen_tcp.erl
@@ -30,7 +30,7 @@
 -include("file.hrl").
 
 -type option() ::
-        {active,          true | false | once} |
+        {active,          true | false | once | -32768..32767} |
         {buffer,          non_neg_integer()} |
         {delay_send,      boolean()} |
         {deliver,         port | term} |
diff --git a/lib/kernel/src/gen_udp.erl b/lib/kernel/src/gen_udp.erl
index e82b11d2ef..70dceb3679 100644
--- a/lib/kernel/src/gen_udp.erl
+++ b/lib/kernel/src/gen_udp.erl
@@ -26,7 +26,7 @@
 -include("inet_int.hrl").
 
 -type option() ::
-        {active,          true | false | once} |
+        {active,          true | false | once | -32768..32767} |
         {add_membership,  {inet:ip_address(), inet:ip_address()}} |
         {broadcast,       boolean()} |
         {buffer,          non_neg_integer()} |
diff --git a/lib/kernel/src/inet.erl b/lib/kernel/src/inet.erl
index 9cfd3819f0..7261d6486f 100644
--- a/lib/kernel/src/inet.erl
+++ b/lib/kernel/src/inet.erl
@@ -667,6 +667,9 @@ con_opt([Opt | Opts], R, As) ->
 		false ->
 		    {error, badarg}
 	    end;
+        {active,N} when is_integer(N), N < 32768, N >= -32768 ->
+            NOpts = lists:keydelete(active, 1, R#connect_opts.opts),
+            con_opt(Opts, R#connect_opts { opts = [{active,N}|NOpts] }, As);
 	{Name,Val} when is_atom(Name) -> con_add(Name, Val, R, Opts, As);
 	_ -> {error, badarg}
     end;
@@ -733,6 +736,9 @@ list_opt([Opt | Opts], R, As) ->
 		false ->
 		    {error, badarg}
 	    end;
+        {active,N} when is_integer(N), N < 32768, N >= -32768 ->
+            NOpts = lists:keydelete(active, 1, R#listen_opts.opts),
+            list_opt(Opts, R#listen_opts { opts = [{active,N}|NOpts] }, As);
 	{Name,Val} when is_atom(Name) -> list_add(Name, Val, R, Opts, As);
 	_ -> {error, badarg}
     end;
@@ -787,6 +793,9 @@ udp_opt([Opt | Opts], R, As) ->
 		false ->
 		    {error, badarg}
 	    end;
+        {active,N} when is_integer(N), N < 32768, N >= -32768 ->
+            NOpts = lists:keydelete(active, 1, R#udp_opts.opts),
+            udp_opt(Opts, R#udp_opts { opts = [{active,N}|NOpts] }, As);
 	{Name,Val} when is_atom(Name) -> udp_add(Name, Val, R, Opts, As);
 	_ -> {error, badarg}
     end;
@@ -805,7 +814,7 @@ udp_add(Name, Val, R, Opts, As) ->
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %  Currently supported options include:
 %  (*) {mode,   list|binary}	 or just list|binary
-%  (*) {active, true|false|once}
+%  (*) {active, true|false|once|N}
 %  (*) {sctp_module, inet_sctp|inet6_sctp} or just inet|inet6
 %  (*) options set via setsockopt.
 %      The full list is below in sctp_options/0 .
@@ -867,6 +876,9 @@ sctp_opt([Opt|Opts], Mod, R, As) ->
 		false ->
 		    {error, badarg}
 	    end;
+        {active,N} when is_integer(N), N < 32768, N >= -32768 ->
+            NOpts = lists:keydelete(active, 1, R#sctp_opts.opts),
+            sctp_opt(Opts, Mod, R#sctp_opts { opts = [{active,N}|NOpts] }, As);
 	{Name,Val}	-> sctp_opt (Opts, Mod, R, As, Name, Val);
 	_ -> {error,badarg}
     end;
diff --git a/lib/kernel/src/inet_int.hrl b/lib/kernel/src/inet_int.hrl
index 18a4a61b2f..024a5fd3b6 100644
--- a/lib/kernel/src/inet_int.hrl
+++ b/lib/kernel/src/inet_int.hrl
@@ -46,6 +46,7 @@
 -define(INET_PASSIVE, 0).
 -define(INET_ACTIVE,  1).
 -define(INET_ONCE,    2). % Active once then passive
+-define(INET_MULTI,   3). % Active N then passive
 
 %% state codes (getstatus, INET_REQ_GETSTATUS)
 -define(INET_F_OPEN,         16#0001).
diff --git a/lib/kernel/test/gen_sctp_SUITE.erl b/lib/kernel/test/gen_sctp_SUITE.erl
index e89cb44797..6dad52395b 100644
--- a/lib/kernel/test/gen_sctp_SUITE.erl
+++ b/lib/kernel/test/gen_sctp_SUITE.erl
@@ -35,8 +35,9 @@
     open_unihoming_ipv6_socket/1,
     open_multihoming_ipv6_socket/1,
     open_multihoming_ipv4_and_ipv6_socket/1,
-    basic_stream/1, xfer_stream_min/1, peeloff_active_once/1,
-    peeloff_active_true/1, buffers/1]).
+    basic_stream/1, xfer_stream_min/1, active_n/1,
+    peeloff_active_once/1, peeloff_active_true/1, peeloff_active_n/1,
+    buffers/1]).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
@@ -46,9 +47,9 @@ all() ->
      open_multihoming_ipv4_socket,
      open_unihoming_ipv6_socket,
      open_multihoming_ipv6_socket,
-     open_multihoming_ipv4_and_ipv6_socket,
+     open_multihoming_ipv4_and_ipv6_socket, active_n,
      basic_stream, xfer_stream_min, peeloff_active_once,
-     peeloff_active_true, buffers].
+     peeloff_active_true, peeloff_active_n, buffers].
 
 groups() -> 
     [].
@@ -767,6 +768,106 @@ implicit_inet6(S1, Addr) ->
 	  end,
     ?line ok = gen_sctp:close(S2).
 
+active_n(doc) ->
+    "Verify {active,N} socket management";
+active_n(suite) ->
+    [];
+active_n(Config) when is_list(Config) ->
+    N = 3,
+    S1 = ok(gen_sctp:open([{active,N}])),
+    [{active,N}] = ok(inet:getopts(S1, [active])),
+    ok = inet:setopts(S1, [{active,-N}]),
+    receive
+        {sctp_passive, S1} -> ok
+    after
+        5000 ->
+            exit({error,sctp_passive_failure})
+    end,
+    [{active,false}] = ok(inet:getopts(S1, [active])),
+    ok = inet:setopts(S1, [{active,0}]),
+    receive
+        {sctp_passive, S1} -> ok
+    after
+        5000 ->
+            exit({error,sctp_passive_failure})
+    end,
+    ok = inet:setopts(S1, [{active,32767}]),
+    {error,einval} = inet:setopts(S1, [{active,1}]),
+    {error,einval} = inet:setopts(S1, [{active,-32769}]),
+    ok = inet:setopts(S1, [{active,-32768}]),
+    receive
+        {sctp_passive, S1} -> ok
+    after
+        5000 ->
+            exit({error,sctp_passive_failure})
+    end,
+    [{active,false}] = ok(inet:getopts(S1, [active])),
+    ok = inet:setopts(S1, [{active,N}]),
+    ok = inet:setopts(S1, [{active,true}]),
+    [{active,true}] = ok(inet:getopts(S1, [active])),
+    receive
+        _ -> exit({error,active_n})
+    after
+        0 ->
+            ok
+    end,
+    ok = inet:setopts(S1, [{active,N}]),
+    ok = inet:setopts(S1, [{active,once}]),
+    [{active,once}] = ok(inet:getopts(S1, [active])),
+    receive
+        _ -> exit({error,active_n})
+    after
+        0 ->
+            ok
+    end,
+    {error,einval} = inet:setopts(S1, [{active,32768}]),
+    ok = inet:setopts(S1, [{active,false}]),
+    [{active,false}] = ok(inet:getopts(S1, [active])),
+    ok = gen_sctp:listen(S1, true),
+    S1Port = ok(inet:port(S1)),
+    S2 = ok(gen_sctp:open(0, [{active,false}])),
+    Assoc = ok(gen_sctp:connect(S2, "localhost", S1Port, [])),
+    ok = inet:setopts(S1, [{active,N}]),
+    [{active,N}] = ok(inet:getopts(S1, [active])),
+    LoopFun = fun(Count, Count, _Fn) ->
+		      receive
+			  {sctp_passive,S1} ->
+			      ok
+		      after
+			  5000 ->
+			      exit({error,timeout})
+		      end;
+		 (I, Count, Fn) ->
+		      Msg = list_to_binary("message "++integer_to_list(I)),
+		      ok = gen_sctp:send(S2, Assoc, 0, Msg),
+		      receive
+			  {sctp,S1,_,_,{[SR],Msg}} when is_record(SR, sctp_sndrcvinfo) ->
+			      Fn(I+1, Count, Fn);
+			  {sctp,S1,_,_,_} ->
+			      %% ignore non-data messages
+			      ok = inet:setopts(S1, [{active,1}]),
+			      Fn(I, Count, Fn);
+			  Other ->
+			      exit({unexpected, Other})
+		      after
+			  5000 ->
+			      exit({error,timeout})
+		      end
+	      end,
+    ok = LoopFun(1, N, LoopFun),
+    S3 = ok(gen_sctp:open([{active,0}])),
+    receive
+        {sctp_passive,S3} ->
+            [{active,false}] = ok(inet:getopts(S3, [active]))
+    after
+        5000 ->
+            exit({error,udp_passive})
+    end,
+    ok = gen_sctp:close(S3),
+    ok = gen_sctp:close(S2),
+    ok = gen_sctp:close(S1),
+    ok.
+
 basic_stream(doc) ->
     "Hello world stream socket";
 basic_stream(suite) ->
@@ -941,6 +1042,14 @@ peeloff_active_true(suite) ->
 peeloff_active_true(Config) ->
     peeloff(Config, [{active,true}]).
 
+peeloff_active_n(doc) ->
+    "Peel off an SCTP stream socket ({active,N})";
+peeloff_active_n(suite) ->
+    [];
+
+peeloff_active_n(Config) ->
+    peeloff(Config, [{active,1}]).
+
 peeloff(Config, SockOpts) when is_list(Config) ->
     ?line Addr = {127,0,0,1},
     ?line Stream = 0,
@@ -1519,7 +1628,13 @@ s_loop(Socket, Timeout, Parent, Handler, State) ->
     end.
 
 again(Socket) ->
-    inet:setopts(Socket, [{active,once}]).
+    receive
+	{sctp_passive,Socket} ->
+	    [{active, false}] = ok(inet:getopts(Socket, [active])),
+	    ok = inet:setopts(Socket,[{active,1}])
+    after 0 ->
+	    ok = inet:setopts(Socket, [{active,once}])
+    end.
 
 gb_push(Key, Val, GBT) ->
     case gb_trees:lookup(Key, GBT) of
diff --git a/lib/kernel/test/gen_tcp_misc_SUITE.erl b/lib/kernel/test/gen_tcp_misc_SUITE.erl
index ee271fbdfa..ee8bfcceb1 100644
--- a/lib/kernel/test/gen_tcp_misc_SUITE.erl
+++ b/lib/kernel/test/gen_tcp_misc_SUITE.erl
@@ -25,7 +25,7 @@
 -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, 
 	 init_per_group/2,end_per_group/2, 
 	 controlling_process/1, controlling_process_self/1,
-	 no_accept/1, close_with_pending_output/1,
+	 no_accept/1, close_with_pending_output/1, active_n/1,
 	 data_before_close/1, iter_max_socks/1, get_status/1,
 	 passive_sockets/1, accept_closed_by_other_process/1,
 	 init_per_testcase/2, end_per_testcase/2,
@@ -70,7 +70,7 @@ suite() -> [{ct_hooks,[ts_install_cth]}].
 all() -> 
     [controlling_process, controlling_process_self, no_accept,
      close_with_pending_output, data_before_close,
-     iter_max_socks, passive_sockets,
+     iter_max_socks, passive_sockets, active_n,
      accept_closed_by_other_process, otp_3924, closed_socket,
      shutdown_active, shutdown_passive, shutdown_pending,
      default_options, http_bad_packet, busy_send,
@@ -407,6 +407,114 @@ send_loop(Sock, Data, Left) ->
     ok = gen_tcp:send(Sock, Data),
     send_loop(Sock, Data, Left-1).
 
+%% Test {active,N} option
+active_n(doc) ->
+    ["Verify operation of the {active,N} option."];
+active_n(suite) -> [];
+active_n(Config) when is_list(Config) ->
+    N = 3,
+    LS = ok(gen_tcp:listen(0, [{active,N}])),
+    [{active,N}] = ok(inet:getopts(LS, [active])),
+    ok = inet:setopts(LS, [{active,-N}]),
+    receive
+        {tcp_passive, LS} -> ok
+    after
+        5000 ->
+            exit({error,tcp_passive_failure})
+    end,
+    [{active,false}] = ok(inet:getopts(LS, [active])),
+    ok = inet:setopts(LS, [{active,0}]),
+    receive
+        {tcp_passive, LS} -> ok
+    after
+        5000 ->
+            exit({error,tcp_passive_failure})
+    end,
+    ok = inet:setopts(LS, [{active,32767}]),
+    {error,einval} = inet:setopts(LS, [{active,1}]),
+    {error,einval} = inet:setopts(LS, [{active,-32769}]),
+    ok = inet:setopts(LS, [{active,-32768}]),
+    receive
+        {tcp_passive, LS} -> ok
+    after
+        5000 ->
+            exit({error,tcp_passive_failure})
+    end,
+    [{active,false}] = ok(inet:getopts(LS, [active])),
+    ok = inet:setopts(LS, [{active,N}]),
+    ok = inet:setopts(LS, [{active,true}]),
+    [{active,true}] = ok(inet:getopts(LS, [active])),
+    receive
+        _ -> exit({error,active_n})
+    after
+        0 ->
+            ok
+    end,
+    ok = inet:setopts(LS, [{active,N}]),
+    ok = inet:setopts(LS, [{active,once}]),
+    [{active,once}] = ok(inet:getopts(LS, [active])),
+    receive
+        _ -> exit({error,active_n})
+    after
+        0 ->
+            ok
+    end,
+    {error,einval} = inet:setopts(LS, [{active,32768}]),
+    ok = inet:setopts(LS, [{active,false}]),
+    [{active,false}] = ok(inet:getopts(LS, [active])),
+    Port = ok(inet:port(LS)),
+    C = ok(gen_tcp:connect("localhost", Port, [{active,N}])),
+    [{active,N}] = ok(inet:getopts(C, [active])),
+    S = ok(gen_tcp:accept(LS)),
+    ok = inet:setopts(S, [{active,N}]),
+    [{active,N}] = ok(inet:getopts(S, [active])),
+    repeat(3,
+           fun(I) ->
+                   Msg = "message "++integer_to_list(I),
+                   ok = gen_tcp:send(C, Msg),
+                   receive
+                       {tcp,S,Msg} ->
+                           ok = gen_tcp:send(S, Msg)
+                   after
+                       5000 ->
+                           exit({error,timeout})
+                   end,
+                   receive
+                       {tcp,C,Msg} ->
+                           ok
+                   after
+                       5000 ->
+                           exit({error,timeout})
+                   end
+           end),
+    receive
+        {tcp_passive,S} ->
+            [{active,false}] = ok(inet:getopts(S, [active]))
+    after
+        5000 ->
+            exit({error,tcp_passive})
+    end,
+    receive
+        {tcp_passive,C} ->
+            [{active,false}] = ok(inet:getopts(C, [active]))
+    after
+        5000 ->
+            exit({error,tcp_passive})
+    end,
+    LS2 = ok(gen_tcp:listen(0, [{active,0}])),
+    receive
+        {tcp_passive,LS2} ->
+            [{active,false}] = ok(inet:getopts(LS2, [active]))
+    after
+        5000 ->
+            exit({error,tcp_passive})
+    end,
+    ok = gen_tcp:close(LS2),
+    ok = gen_tcp:close(C),
+    ok = gen_tcp:close(S),
+    ok = gen_tcp:close(LS),
+    ok.
+
 -define(OTP_3924_MAX_DELAY, 100).
 %% Taken out of the blue, but on intra host connections
 %% I expect propagation of a close to be quite fast
@@ -2659,3 +2767,5 @@ oct_aloop(S,X,Times) ->
 	    gen_tcp:close(S),
 	    closed
     end.
+
+ok({ok,V}) -> V.
diff --git a/lib/kernel/test/gen_udp_SUITE.erl b/lib/kernel/test/gen_udp_SUITE.erl
index 4cc6018614..6bb41999c5 100644
--- a/lib/kernel/test/gen_udp_SUITE.erl
+++ b/lib/kernel/test/gen_udp_SUITE.erl
@@ -33,7 +33,7 @@
 	 init_per_group/2,end_per_group/2]).
 -export([init_per_testcase/2, end_per_testcase/2]).
 
--export([send_to_closed/1, 
+-export([send_to_closed/1, active_n/1,
 	 buffer_size/1, binary_passive_recv/1, bad_address/1,
 	 read_packets/1, open_fd/1, connect/1, implicit_inet6/1]).
 
@@ -42,7 +42,7 @@ suite() -> [{ct_hooks,[ts_install_cth]}].
 all() -> 
     [send_to_closed, buffer_size, binary_passive_recv,
      bad_address, read_packets, open_fd, connect,
-     implicit_inet6].
+     implicit_inet6, active_n].
 
 groups() -> 
     [].
@@ -465,6 +465,108 @@ open_fd(Config) when is_list(Config) ->
 	    ?t:fail(io_lib:format("~w", [flush()]))
     end.
 
+active_n(Config) when is_list(Config) ->
+    N = 3,
+    S1 = ok(gen_udp:open(0, [{active,N}])),
+    [{active,N}] = ok(inet:getopts(S1, [active])),
+    ok = inet:setopts(S1, [{active,-N}]),
+    receive
+        {udp_passive, S1} -> ok
+    after
+        5000 ->
+            exit({error,udp_passive_failure})
+    end,
+    [{active,false}] = ok(inet:getopts(S1, [active])),
+    ok = inet:setopts(S1, [{active,0}]),
+    receive
+        {udp_passive, S1} -> ok
+    after
+        5000 ->
+            exit({error,udp_passive_failure})
+    end,
+    ok = inet:setopts(S1, [{active,32767}]),
+    {error,einval} = inet:setopts(S1, [{active,1}]),
+    {error,einval} = inet:setopts(S1, [{active,-32769}]),
+    ok = inet:setopts(S1, [{active,-32768}]),
+    receive
+        {udp_passive, S1} -> ok
+    after
+        5000 ->
+            exit({error,udp_passive_failure})
+    end,
+    [{active,false}] = ok(inet:getopts(S1, [active])),
+    ok = inet:setopts(S1, [{active,N}]),
+    ok = inet:setopts(S1, [{active,true}]),
+    [{active,true}] = ok(inet:getopts(S1, [active])),
+    receive
+        _ -> exit({error,active_n})
+    after
+        0 ->
+            ok
+    end,
+    ok = inet:setopts(S1, [{active,N}]),
+    ok = inet:setopts(S1, [{active,once}]),
+    [{active,once}] = ok(inet:getopts(S1, [active])),
+    receive
+        _ -> exit({error,active_n})
+    after
+        0 ->
+            ok
+    end,
+    {error,einval} = inet:setopts(S1, [{active,32768}]),
+    ok = inet:setopts(S1, [{active,false}]),
+    [{active,false}] = ok(inet:getopts(S1, [active])),
+    S1Port = ok(inet:port(S1)),
+    S2 = ok(gen_udp:open(0, [{active,N}])),
+    S2Port = ok(inet:port(S2)),
+    [{active,N}] = ok(inet:getopts(S2, [active])),
+    ok = inet:setopts(S1, [{active,N}]),
+    [{active,N}] = ok(inet:getopts(S1, [active])),
+    lists:foreach(
+      fun(I) ->
+              Msg = "message "++integer_to_list(I),
+              ok = gen_udp:send(S2, "localhost", S1Port, Msg),
+              receive
+                  {udp,S1,_,S2Port,Msg} ->
+                      ok = gen_udp:send(S1, "localhost", S2Port, Msg)
+              after
+                  5000 ->
+                      exit({error,timeout})
+              end,
+              receive
+                  {udp,S2,_,S1Port,Msg} ->
+                      ok
+              after
+                  5000 ->
+                      exit({error,timeout})
+              end
+      end, lists:seq(1,N)),
+    receive
+        {udp_passive,S1} ->
+            [{active,false}] = ok(inet:getopts(S1, [active]))
+    after
+        5000 ->
+            exit({error,udp_passive})
+    end,
+    receive
+        {udp_passive,S2} ->
+            [{active,false}] = ok(inet:getopts(S2, [active]))
+    after
+        5000 ->
+            exit({error,udp_passive})
+    end,
+    S3 = ok(gen_udp:open(0, [{active,0}])),
+    receive
+        {udp_passive,S3} ->
+            [{active,false}] = ok(inet:getopts(S3, [active]))
+    after
+        5000 ->
+            exit({error,udp_passive})
+    end,
+    ok = gen_udp:close(S3),
+    ok = gen_udp:close(S2),
+    ok = gen_udp:close(S1),
+    ok.
 
 %
 % Utils