Fix SCTP multihoming

Setting several ip addresses for an SCTP socket worked only for IPv4
on Linux.  For IPv6 and for other for instance Solaris and FreeBSD, it
failed with badarg for both IPv4 and IPv6.

For the first address specified to gen_sctp:open, bind is now called,
while for any following addresses, sctp_bindx is called, repeatedly,
with one address at a time.  Previously, sctp_bindx was called for all
addresses in one go, with the addresses in reverse order, and bind was
not called at all if more than one address was specified.  Both
Solaris and FreeBSD requires bind to have been called before calling
sctp_bindx, and FreeBSD additionally allows at most one address at a
time in the call to sctp_bindx.

For some versions of Linux, for instance SuSE 10, the port can be 0
only for the call to bind but not for subsequent calls to sctp_bindx,
so replace with the port number assigned by the operating system.

1 files changed, 35 insertions, 7 deletions

diff --git a/lib/kernel/src/inet.erl b/lib/kernel/src/inet.erl
index 0bb5444dbb..1a03424f88 100644
--- a/lib/kernel/src/inet.erl
+++ b/lib/kernel/src/inet.erl
@@ -763,8 +763,12 @@ sctp_opt([Opt|Opts], Mod, R, As) ->
 	{Name,Val}	-> sctp_opt (Opts, Mod, R, As, Name, Val);
 	_ -> {error,badarg}
     end;
-sctp_opt([], _Mod, R, _SockOpts) ->
-    {ok, R}.
+sctp_opt([], _Mod, #sctp_opts{ifaddr=IfAddr}=R, _SockOpts) ->
+    if is_list(IfAddr) ->
+	    {ok, R#sctp_opts{ifaddr=lists:reverse(IfAddr)}};
+       true ->
+	    {ok, R}
+    end.
 
 sctp_opt(Opts, Mod, R, As, Name, Val) ->
     case add_opt(Name, Val, R#sctp_opts.opts, As) of
@@ -1015,11 +1019,7 @@ open(Fd, Addr, Port, Opts, Protocol, Family, Type, Module) when Fd < 0 ->
 	    case prim_inet:setopts(S, Opts) of
 		ok ->
 		    case if is_list(Addr) ->
-				 prim_inet:bind(S, add,
-						[case A of
-						     {_,_} -> A;
-						     _     -> {A,Port}
-						 end || A <- Addr]);
+				 bindx(S, Addr, Port);
 			    true ->
 				 prim_inet:bind(S, Addr, Port)
 			 end of
@@ -1040,6 +1040,34 @@ open(Fd, Addr, Port, Opts, Protocol, Family, Type, Module) when Fd < 0 ->
 open(Fd, _Addr, _Port, Opts, Protocol, Family, Type, Module) ->
     fdopen(Fd, Opts, Protocol, Family, Type, Module).
 
+bindx(S, [Addr], Port0) ->
+    {IP, Port} = set_bindx_port(Addr, Port0),
+    prim_inet:bind(S, IP, Port);
+bindx(S, Addrs, Port0) ->
+    [{IP, Port} | Rest] = [set_bindx_port(Addr, Port0) || Addr <- Addrs],
+    case prim_inet:bind(S, IP, Port) of
+	{ok, AssignedPort} when Port =:= 0 ->
+	    %% On newer Linux kernels, Solaris and FreeBSD, calling
+	    %% bindx with port 0 is ok, but on SuSE 10, it results in einval
+	    Rest2 = [change_bindx_0_port(Addr, AssignedPort) || Addr <- Rest],
+	    prim_inet:bind(S, add, Rest2);
+	{ok, _} ->
+	    prim_inet:bind(S, add, Rest);
+	Error ->
+	    Error
+    end.
+
+set_bindx_port({_IP, _Port}=Addr, _OtherPort) ->
+    Addr;
+set_bindx_port(IP, Port) ->
+    {IP, Port}.
+
+change_bindx_0_port({IP, 0}, AssignedPort) ->
+    {IP, AssignedPort};
+change_bindx_0_port({_IP, _Port}=Addr, _AssignedPort) ->
+    Addr.
+
+
 -spec fdopen(Fd :: non_neg_integer(),
 	     Opts :: [socket_setopt()],
 	     Protocol :: socket_protocol(),