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11 files changed, 517 insertions, 0 deletions

diff --git a/src/fib.erl b/src/fib.erl
new file mode 100644
index 0000000..130e8ec
--- /dev/null
+++ b/src/fib.erl
@@ -0,0 +1,37 @@
+-module(fib).
+-export([tables/0, current_table/0]).
+-export([list/0, list/1]).
+-export_types([table/0, flags/0, entry/0]).
+
+-type table() :: non_neg_integer.
+
+-type flags() :: [].
+
+-type entry() :: #{destination := inet:ip_address() | default,
+                  netmask := inet:ip_address() | undefined,
+                  gateway := inet:ip_address() | {mac, string()} | {link, integer()},
+                  scope := string() | undefined,
+                  interface := string(),
+                  flags := flags(),
+                  expire := undefined}.
+
+-spec tables() -> [table()].
+tables() ->
+    persistent_term:get('fib/tables').
+
+-spec current_table() -> table().
+current_table() ->
+    persistent_term:get('fib/current_table').
+
+-spec list() -> [entry()].
+list() ->
+    Mod = mod(),
+    Mod:list(Mod:default_table()).
+
+-spec list(table) -> [entry()].
+list(Table) ->
+    Mod = mod(),
+    Mod:list(Table).
+
+mod() ->
+    persistent_term:get('fib/module').
diff --git a/src/fib.hrl b/src/fib.hrl
new file mode 100644
index 0000000..6f88bfb
--- /dev/null
+++ b/src/fib.hrl
@@ -0,0 +1,3 @@
+-define(SOCK_RAW, 3).
+-define(AF_UNSPEC, 0).
+-define(PF_ROUTE, 17).
diff --git a/src/fib_app.erl b/src/fib_app.erl
new file mode 100644
index 0000000..3acb41c
--- /dev/null
+++ b/src/fib_app.erl
@@ -0,0 +1,16 @@
+-module(fib_app).
+-behaviour(application).
+
+-export([start/2]).
+-export([stop/1]).
+
+start(_Type, _Args) ->
+    %% Find which platform module to use and cache persistent data.
+    {ok, Mod} = fib_util:module(),
+    persistent_term:put('fib/module', Mod),
+    persistent_term:put('fib/current_table', Mod:current_table()),
+    persistent_term:put('fib/tables', Mod:tables()),
+    fib_sup:start_link().
+
+stop(_State) ->
+    ok.
diff --git a/src/fib_behaviour.erl b/src/fib_behaviour.erl
new file mode 100644
index 0000000..fd96ca7
--- /dev/null
+++ b/src/fib_behaviour.erl
@@ -0,0 +1,7 @@
+-module(fib_behaviour).
+
+-callback tables() -> [fib:table()].
+-callback default_table() -> fib:table().
+-callback current_table() -> fib:table().
+
+-callback list(fib:table()) -> {ok, []} | {error, {no_table, fib:table()}}.
diff --git a/src/fib_freebsd.erl b/src/fib_freebsd.erl
new file mode 100644
index 0000000..b85d458
--- /dev/null
+++ b/src/fib_freebsd.erl
@@ -0,0 +1,35 @@
+-module(fib_freebsd).
+-behaviour(fib_behaviour).
+-export([default_table/0, current_table/0, tables/0]).
+-export([list/1]).
+
+default_table() ->
+     1.
+
+current_table() ->
+    case os:cmd("sysctl net.my_fibnum") of
+        [$n, $e, $t, $., $m, $y, $_, $f, $i, $n, $b, $u, $m, $:, $\s | Rest] ->
+            {ok, list_to_integer(string:trim(Rest))};
+        _ ->
+            error
+    end.
+
+tables() ->
+    case os:cmd("sysctl net.fibs") of
+        [$n, $e, $t, $., $f, $i, $b, $s, $:, $\s | Rest] ->
+            Count = list_to_integer(string:trim(Rest)),
+            {ok, lists:seq(1, Count)};
+        _ ->
+            error
+    end.
+
+list(Table) ->
+    case lists:member(fib:tables(), Table) of
+        true ->
+            do_list(Table);
+        _ ->
+            {error, {no_table, Table}}
+    end.
+
+do_list(Table) ->
+    os:cmd(["setfib ", Table, " netstat -rn"]).
diff --git a/src/fib_linux.erl b/src/fib_linux.erl
new file mode 100644
index 0000000..f87e885
--- /dev/null
+++ b/src/fib_linux.erl
@@ -0,0 +1,18 @@
+-module(fib_linux).
+-behaviour(fib_behaviour).
+-export([default_table/0, current_table/0, tables/0]).
+-export([list/1]).
+
+%% Linux has 255 routing tables.
+
+default_table() ->
+    254.
+
+current_table() ->
+    default_table().
+
+tables() ->
+    lists:seq(1, 255).
+
+list(_Table) ->
+    todo.
diff --git a/src/fib_macos.erl b/src/fib_macos.erl
new file mode 100644
index 0000000..3df046d
--- /dev/null
+++ b/src/fib_macos.erl
@@ -0,0 +1,179 @@
+-module(fib_macos).
+-behaviour(fib_behaviour).
+-include("fib_macos.hrl").
+-export([default_table/0, current_table/0, tables/0]).
+-export([list/1]).
+-export([monitor/1]).
+-export([parse_pf_route_packet/1]).
+
+%% MacOS has no tables.
+
+default_table() ->
+    ?TABLE.
+
+current_table() ->
+    ?TABLE.
+
+tables() ->
+    {ok, [?TABLE]}.
+
+list(?TABLE) ->
+    Netstat = os:cmd("netstat -rn"),
+    List = string:split(string:trim(Netstat), [$\n], all),
+    do_list(List, []);
+list(Table) ->
+    {error, {no_table, Table}}.
+
+monitor(?TABLE) ->
+    spawn_link(fun () ->
+                      fib_pf_route_socket:open(fun (_) -> noop end, fun parse_pf_route_packet/1)
+              end);
+monitor(Table) ->
+    {error, {no_table, Table}}.
+
+%% rt_msghdr struct followed by rt_metrics and a list of sockaddr
+
+%% MacOS 12
+parse_pf_route_packet(<<% struct rt_msghdr (len removed)
+                        ?RTM_VERSION:8/little-unsigned-integer,
+                        Type:8/little-unsigned-integer,
+                        Index:32/little-unsigned-integer,
+                        Flags:32/little-signed-integer,
+                        Addrs:32/little-signed-integer,
+                        Pid:32/little-signed-integer,
+                        Seq:32/little-signed-integer,
+                        Errno:32/little-signed-integer,
+                        Use:32/little-signed-integer,
+                        Inits:32/little-unsigned-integer,
+                        % struct rt_metrics
+                        Locks:32/little-unsigned-integer,
+                        Mtu:32/little-unsigned-integer,
+                        Hopcount:32/little-unsigned-integer,
+                        Expire:32/little-signed-integer,
+                        Recv:32/little-unsigned-integer,
+                        Send:32/little-unsigned-integer,
+                        Ssthresh:32/little-unsigned-integer,
+                        Rtt:32/little-unsigned-integer,
+                        Rttvar:32/little-unsigned-integer,
+                        Pksent:32/little-unsigned-integer,
+                        State:32/little-unsigned-integer,
+                        Filler1:32/little-unsigned-integer,
+                        Filler2:32/little-unsigned-integer,
+                        Filler3:32/little-unsigned-integer,
+                        % List of sockaddrs
+                        BinaryAddrs/binary
+                      >>) ->
+    Rt = #macos_rt{type = Type, ifp_index = Index, flags = Flags, addrs = Addrs, pid = Pid, seq = Seq, errno = Errno, use = Use,
+                   metrics_init = Inits, metrics_lock = Locks, mtu = Mtu, hopcount = Hopcount, expire = Expire, recvpipe = Recv,
+                   sendpipe = Send, ssthresh = Ssthresh, rtt = Rtt, rttvar = Rttvar, pksent = Pksent, state = State,
+                   filler = {Filler1, Filler2, Filler3}},
+    parse_rt(Rt, BinaryAddrs).
+
+parse_rt(Rt0, BinaryAddrs) ->
+   Rt1 = Rt0#macos_rt{type = maps:get(Rt0#macos_rt.type, ?RTM, Rt0#macos_rt.type),
+                     flags = bitmask(?RTF, Rt0#macos_rt.flags),
+                     addrs = bitmask(?RTA, Rt0#macos_rt.addrs),
+                     metrics_init = bitmask(?RTV, Rt0#macos_rt.metrics_init),
+                     metrics_lock = bitmask(?RTV, Rt0#macos_rt.metrics_lock)},
+    logger:warning("fib_macos:monitor Rt = ~p~nBinary: ~p", [Rt1, BinaryAddrs]),
+    Rt = get_addrs(Rt1#macos_rt.addrs, BinaryAddrs, Rt1),
+    logger:warning("fib_macos:monitor Rt = ~p", [Rt]),
+    Rt.
+
+get_addrs([_Type | Rest], <<0:32/little-unsigned-integer, Binary/binary>>, Rt) ->
+    get_addrs(Rest, Binary, Rt);
+get_addrs([Type | Rest], <<Len:8/little-unsigned-integer, Family:8/little-unsigned-integer, Content/binary>>, Rt) ->
+    logger:error("fib_macos:get_addrs() ~p len=~p family=~p ~nbinary ~p", [Type, Len, Family, Content]),
+    ToRead = case Type of
+                 netmask -> Len - 1;
+                 _Other -> Len - 2
+             end,
+    <<BinaryAddr:ToRead/binary, Binary/binary>> = Content,
+    Idx = string:str(record_info(fields, macos_rt), [Type]),
+    logger:warning("fib_macos:get_addrs() - get_addr ~p = ~p~nRest ~p~nBinRest = ~p", [Type, BinaryAddr, Rest, Binary]),
+    get_addrs(Rest, Binary, setelement(Idx+1, Rt, process_address(Family, BinaryAddr)));
+get_addrs([], _, Rt) ->
+    Rt.
+
+%% sockaddr_in, without the zeros (? only in netmasks)
+process_address(?AF_INET, <<_Port:16/little-unsigned-integer, A, B, C, D>>) ->
+    {A, B, C, D};
+%% sockaddr_in full ; _Zero is `sin_zero`.
+process_address(?AF_INET, <<_Port:16/little-unsigned-integer, A, B, C, D, _Zero:64/little-unsigned-integer>>) ->
+    {A, B, C, D};
+%% ???????? netmask in a RTM_GET message. see fib_macos_SUITE:pckt_rt_get.
+process_address(255, <<255, 255, A, B, C, D>>) ->
+    {A, B, C, D};
+process_address(Family, Data) ->
+    logger:error("macos:process_address: no clause for family ~p = ~p", [Family, Data]),
+    {Family, Data}.
+
+bitmask(List, Integer) ->
+    bitmask(List, Integer, []).
+
+bitmask([{V, Name} | Rest], I, Acc) ->
+    if
+        (I band V) =:= V ->
+            bitmask(Rest, I, [Name | Acc]);
+        true ->
+            bitmask(Rest, I, Acc)
+    end;
+bitmask([], _, Acc) ->
+    lists:reverse(Acc).
+
+do_list([], Acc) ->
+    Acc;
+do_list([[] | Rest], Acc) ->
+    do_list(Rest, Acc);
+
+%% Header "Routing Tables"
+do_list([[$R, $o, $u, $t, $i, $n, $g | _] | Rest], Acc) ->
+    do_list(Rest, Acc);
+%% Header "Internet"/"Internet6"
+do_list([[$I, $n, $t, $e, $r, $n, $e, $t | _] | Rest], Acc) ->
+    do_list(Rest, Acc);
+%% Header fields
+do_list([[$D, $e, $s, $t, $i, $n, $a, $t, $i, $o, $n | _] | Rest], Acc) ->
+    do_list(Rest, Acc);
+%% Data line
+do_list([Line | Rest], Acc) ->
+    [Destination, Gateway, Flags, Netif | Expire] = string:lexemes(Line, [$\s, $\t]),
+    {DestIp, Scope, Netmask} = case Destination of
+                            "default" -> {default, undefined, undefined};
+                            IPStr -> fib_util:parse_ip_address_with_netmask(IPStr)
+                        end,
+    GW = case Gateway of
+             [$l, $i, $n, $k, $# | Num] ->
+                 {link, list_to_integer(Num)};
+             GWStr ->
+                 case inet:parse_address(GWStr) of
+                     {ok, GwIP} -> GwIP;
+                     {error, einval} -> {mac, GWStr}
+                 end
+         end,
+    Route = #{destination => DestIp, netmask => Netmask, scope => Scope, gateway => GW, flags => [flag(F) || F <- Flags], interface => Netif, expire => Expire},
+    do_list(Rest, [Route | Acc]).
+
+flag($1) -> proto1;
+flag($2) -> proto2;
+flag($3) -> proto3;
+flag($B) -> blackhole;
+flag($b) -> broadcast;
+flag($C) -> cloning;
+flag($c) -> prcloning;
+flag($D) -> dynamic;
+flag($G) -> gateway;
+flag($H) -> host;
+flag($I) -> ifscope;
+flag($i) -> ifref;
+flag($L) -> llinfo;
+flag($M) -> modified;
+flag($m) -> multicast;
+flag($R) -> reject;
+flag($r) -> router;
+flag($S) -> static;
+flag($U) -> up;
+flag($W) -> wascloned;
+flag($X) -> xresolve;
+flag($Y) -> proxy;
+flag($g) -> global.
diff --git a/src/fib_macos.hrl b/src/fib_macos.hrl
new file mode 100644
index 0000000..d1cd1a1
--- /dev/null
+++ b/src/fib_macos.hrl
@@ -0,0 +1,146 @@
+-define(TABLE, 1).
+
+%% Constants and structs are mostly defined in `net/route.h`.
+%% /Library/Developer/CommandLineTools/SDKs/MacOSX12.0.sdk/usr/include/net/route.h
+
+-define(RTM_VERSION, 5).
+
+%% PF_ROUTE messages types
+-define(RTM_ADD, 1).
+-define(RTM_DELETE, 2).
+-define(RTM_CHANGE, 3).
+-define(RTM_GET, 4).
+-define(RTM_REDIRECT, 6).
+-define(RTM_MISS, 7).
+-define(RTM_RESOLVE, 16#b).
+-define(RTM_NEWADDR, 16#c).
+-define(RTM_DELADDR, 16#d).
+-define(RTM_IFINFO, 16#e).
+-define(RTM_NEWMADDR, 16#f).
+-define(RTM_DELMADDR, 16#10).
+-define(RTM_IFINFO2, 16#12).
+-define(RTM_NEWMADDR2, 16#13).
+-define(RTM_GET2, 16#14).
+-define(RTM, #{
+               ?RTM_ADD => add,
+               ?RTM_DELETE => delete,
+               ?RTM_CHANGE => change,
+               ?RTM_GET => get,
+               ?RTM_REDIRECT => redirect,
+               ?RTM_MISS => miss,
+               ?RTM_RESOLVE => resolve,
+               ?RTM_NEWADDR => newaddr,
+               ?RTM_DELADDR => deladdr,
+               ?RTM_IFINFO => ifinfo,
+               ?RTM_NEWMADDR => newmaddr,
+               ?RTM_DELMADDR => delmaddr,
+               ?RTM_IFINFO2 => ifinfo2,
+               ?RTM_NEWMADDR2 => newmaddr2,
+               ?RTM_GET2 => get2
+              }).
+
+%% Bitmask values for flags
+-define(RTF_UP, 1).
+-define(RTF_GATEWAY, 2).
+-define(RTF_HOST, 4).
+-define(RTF_REJECT, 8).
+-define(RTF_DYNAMIC, 16#10).
+-define(RTF_MODIFIED, 16#20).
+-define(RTF_DONE, 16#40).
+-define(RTF_DELCLONE, 16#80).
+-define(RTF_CLONING, 16#100).
+-define(RTF_XRESOLVE, 16#200).
+-define(RTF_LLDATA, 16#400).
+-define(RTF_STATIC, 16#800).
+-define(RTF_BLACKHOLE, 16#1000).
+-define(RTF_NOIFREF, 16#2000).
+-define(RTF_PROTO2, 16#4000).
+-define(RTF_PROTO1, 16#8000).
+-define(RTF_PRCLONING, 16#10000).
+-define(RTF_WASCLONED, 16#20000).
+-define(RTF_PROTO3, 16#40000).
+-define(RTF_PINNED, 16#100000).
+-define(RTF_LOCAL, 16#200000).
+-define(RTF_BROADCAST, 16#400000).
+-define(RTF_MULTICAST, 16#800000).
+-define(RTF_IFSCOPE, 16#1000000).
+-define(RTF_CONDEMNED, 16#2000000).
+-define(RTF_IFREF, 16#4000000).
+-define(RTF_PROXY, 16#8000000).
+-define(RTF_ROUTER, 16#10000000).
+-define(RTF_DEAD, 16#20000000).
+-define(RTF_GLOBAL, 16#40000000).
+-define(RTF, [{?RTF_UP, up}, {?RTF_GATEWAY, gateway}, {?RTF_HOST, host}, {?RTF_REJECT, reject},
+             {?RTF_DYNAMIC, dynamic}, {?RTF_MODIFIED, modified}, {?RTF_DONE, done}, {?RTF_DELCLONE, delclone},
+              {?RTF_CLONING, cloning}, {?RTF_XRESOLVE, xresolve}, {?RTF_LLDATA, lldata}, {?RTF_STATIC, static},
+              {?RTF_BLACKHOLE, blackhole}, {?RTF_NOIFREF, noifref}, {?RTF_PROTO2, proto2}, {?RTF_PROTO1, proto1},
+              {?RTF_PRCLONING, prcloning}, {?RTF_WASCLONED, wascloned}, {?RTF_PROTO3, proto3}, {?RTF_PINNED, pinned},
+              {?RTF_LOCAL, local}, {?RTF_BROADCAST, broadcast}, {?RTF_MULTICAST, multicast}, {?RTF_IFSCOPE, ifscope},
+              {?RTF_CONDEMNED, condemned}, {?RTF_IFREF, ifref}, {?RTF_PROXY, proxy}, {?RTF_ROUTER, router},
+              {?RTF_DEAD, dead}, {?RTF_GLOBAL, global}]).
+
+%% Bitmask values, rtm_inits and rtm_locks
+-define(RTV_MTU, 1).
+-define(RTV_HOPCOUNT, 2).
+-define(RTV_EXPIRE, 4).
+-define(RTV_RPIPE, 8).
+-define(RTV_SPIPE, 16#10).
+-define(RTV_SSTHRESH, 16#20).
+-define(RTV_RTT, 16#40).
+-define(RTV_RTTVAR, 16#80).
+-define(RTV, [{?RTV_MTU, mtu}, {?RTV_HOPCOUNT, hopcount}, {?RTV_EXPIRE, expire}, {?RTV_RPIPE, recvpipe}, {?RTV_SPIPE, sendpipe},
+              {?RTV_SSTHRESH, ssthresh}, {?RTV_RTT, rtt}, {?RTV_RTTVAR, rttvar}]).
+
+%% Bitmask values for rtm_addrs
+-define(RTA_DST, 1). % destination sockaddr present
+-define(RTA_GATEWAY, 2). % gateway sockaddr present
+-define(RTA_NETMASK, 4). % netmask sockaddr present
+-define(RTA_GENMASK, 8). % cloning mask sockaddr present
+-define(RTA_IFP, 16#10). % interface name sockaddr present
+-define(RTA_IFA, 16#20). % interface addr sockaddr present
+-define(RTA_AUTHOR, 16#40). % sockaddr for addr of redirect
+-define(RTA_BRD, 16#80). % for NEWADDR, broadcast or p-p dest addr
+-define(RTA, [{?RTA_DST, destination}, {?RTA_GATEWAY, gateway}, {?RTA_NETMASK, netmask},
+                          {?RTA_GENMASK, genmask}, {?RTA_IFP, ifp}, {?RTA_IFA, ifa},
+                          {?RTA_AUTHOR, author}, {?RTA_BRD, brd}]).
+
+%% usr/include/sys/socket.h
+-define(AF_UNSPEC, 0).
+-define(AF_INET, 2).
+-define(AF_LINK, 18).
+-define(AF_INET6, 31).
+
+-record(macos_rt, {type, % Message type, atom
+                   flags, % Route flags
+                   addrs, % Addresses list
+                   pid, % Originating pid
+                   seq, % user data
+                   errno, % error number
+                   use, % documented as: "from rentry"
+
+                   % Metrics
+                   metrics_init, % metrics that are initializing
+                   metrics_lock, % metrics that are locked
+                   mtu, % mtu
+                   hopcount, % max hops expected
+                   expire, % lifetime for route
+                   recvpipe, % inbound delay-bandwith product
+                   sendpipe, % outbound delay-bandwith product
+                   ssthresh, % outbound gateway buffer limit
+                   rtt, % estimated round trip time
+                   rttvar, % estimated rtt variance
+                   pksent, % packets sent using this route
+                   state, % route state
+                   filler, % "will be used for TCP's peer-MSS cache"
+
+                   % Addresses
+                   destination, % Destination
+                   gateway, % Gateway
+                   netmask, % netmask
+                   clonemask, % (C: genmask) cloning mask
+                   ifp, % interface name
+                   ifp_index, % (C: index) Scope for associated ifp, if present
+                   ifa, % interface address
+                   author, % author of redirect
+                   brd % (only for type=newaddr) broadcast or p-p destination address
+}).
diff --git a/src/fib_pf_route_socket.erl b/src/fib_pf_route_socket.erl
new file mode 100644
index 0000000..ea07003
--- /dev/null
+++ b/src/fib_pf_route_socket.erl
@@ -0,0 +1,23 @@
+-module(fib_pf_route_socket).
+-export([test/0, open/2]).
+-include("fib.hrl").
+
+test() ->
+    open(fun (_) -> ok end, fun (_) -> ok end).
+
+open(OpenFun, ParseFun) ->
+    {ok, Socket} = socket:open(?PF_ROUTE, ?SOCK_RAW, ?AF_UNSPEC),
+    OpenFun(Socket),
+    recv(Socket, ParseFun).
+
+recv(Socket, ParseFun) ->
+    case socket:recv(Socket, 0) of
+        {ok, <<Len:16/little-unsigned-integer, Rest/binary>>} ->
+            ToRead = Len - 2,
+            <<Pckt:ToRead/binary>> = Rest,
+            logger:warning("Got a packet ~p", [Pckt]),
+            ParseFun(Pckt),
+            recv(Socket, ParseFun);
+        Error ->
+            Error
+    end.
diff --git a/src/fib_sup.erl b/src/fib_sup.erl
new file mode 100644
index 0000000..06efb9d
--- /dev/null
+++ b/src/fib_sup.erl
@@ -0,0 +1,12 @@
+-module(fib_sup).
+-behaviour(supervisor).
+
+-export([start_link/0]).
+-export([init/1]).
+
+start_link() ->
+	supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+init([]) ->
+	Procs = [],
+	{ok, {{one_for_one, 1, 5}, Procs}}.
diff --git a/src/fib_util.erl b/src/fib_util.erl
new file mode 100644
index 0000000..b495f25
--- /dev/null
+++ b/src/fib_util.erl
@@ -0,0 +1,41 @@
+-module(fib_util).
+-export([module/0, parse_ip_address_with_netmask/1]).
+
+module() ->
+    case os:type() of
+        {unix, linux} ->
+            {ok, fib_linux};
+        {unix, darwin} ->
+            {ok, fib_macos};
+        {unix, freebsd} ->
+            {ok, fib_freebsd};
+        unsupported ->
+            {error, {unsupported_platform, unsupported}}
+    end.
+
+-spec parse_ip_address_with_netmask(string()) -> {inet:ip_address(), non_neg_integer()}.
+parse_ip_address_with_netmask(S) ->
+    logger:warning("IPNets ~p", [S]),
+    case re:split(S, "/", [{return, list}, {parts, 2}]) of
+        [Prefix, LenStr] ->
+            {Prefix1, Scope} = ipv6_scope(Prefix),
+            {ok, Addr} = inet:parse_address(Prefix1),
+            {PrefixLen, _} = string:to_integer(LenStr),
+            {Addr, Scope, PrefixLen};
+        [Prefix] ->
+            {Prefix1, Scope} = ipv6_scope(Prefix),
+            {ok, Addr} = inet:parse_address(Prefix1),
+            PrefixLen = case inet_cidr:is_ipv6(Addr) of
+                            true -> 128;
+                            false -> 32
+                        end,
+            {Addr, Scope, PrefixLen}
+    end.
+
+ipv6_scope(Addr) ->
+    case re:split(Addr, "%", [{return, list}, {parts, 2}]) of
+        [IP, Scope] ->
+            {IP, Scope};
+        [IP] ->
+            {IP, undefined}
+    end.