[socket-nif] Add preliminary support for sendmsg

Added function sendmsg/2,3,4. Actually worked on the first try.
Something must be wrong...

Still no supported cmsghdr's (only support headers where the
data part is already a binary, which therefor does not require
any processing). So if the cmsghdrs actually work is unclear.

OTP-14831

2 files changed, 24 insertions, 1 deletions

diff --git a/lib/kernel/test/socket_client.erl b/lib/kernel/test/socket_client.erl
index 094b7eebc5..56424457e0 100644
--- a/lib/kernel/test/socket_client.erl
+++ b/lib/kernel/test/socket_client.erl
@@ -71,6 +71,10 @@ start(Domain, Type, Proto, Addr, Port) ->
     SA = #{family => Domain,
            addr   => Addr,
            port   => Port},
+    %% The way we use tos only works because we
+    %% send so few messages (a new value for every
+    %% message).
+    put(tos, 1),
     do_start(Domain, Type, Proto, SA).
 
 do_start(Domain, stream = Type, Proto, SA) ->
@@ -186,6 +190,7 @@ do_init(Domain, stream = Type, Proto) ->
     i("try (socket) bind"),
     case socket:bind(Sock, any) of
         {ok, _P} ->
+            ok = socket:setopt(Sock, ip, tos, mincost),
             Sock;
         {error, BReason} ->
             throw({bind, BReason})
@@ -271,7 +276,15 @@ send(#client{socket = Sock, type = dgram, dest = Dest}, Msg) ->
     %% i("try send to: "
     %%   "~n   ~p", [Dest]),
     %% ok = socket:setopt(Sock, otp, debug, true),
-    socket:sendto(Sock, Msg, Dest).
+    TOS = get(tos),
+    ok = socket:setopt(Sock, ip, tos, TOS),
+    case socket:sendto(Sock, Msg, Dest) of
+        ok = OK ->
+            put(tos, TOS+1),
+            OK;
+        {error, _} = ERROR ->
+            ERROR
+    end.
 
 recv(#client{socket = Sock, type = stream}) ->
     case socket:recv(Sock) of
diff --git a/lib/kernel/test/socket_server.erl b/lib/kernel/test/socket_server.erl
index f252be1683..34f354be32 100644
--- a/lib/kernel/test/socket_server.erl
+++ b/lib/kernel/test/socket_server.erl
@@ -900,8 +900,18 @@ peek_recvfrom(Sock, BufSz) ->
     end.
 
 
+send(#handler{socket = Sock, msg = true, type = stream}, Msg, _) ->
+    MsgHdr = #{iov => [Msg]},
+    socket:sendmsg(Sock, MsgHdr);
 send(#handler{socket = Sock, type = stream}, Msg, _) ->
     socket:send(Sock, Msg);
+send(#handler{socket = Sock, msg = true, type = dgram}, Msg, Dest) ->
+    MsgHdr = #{addr => Dest,
+               iov  => [Msg]},
+    %% ok = socket:setopt(Sock, otp, debug, true),
+    Res = socket:sendmsg(Sock, MsgHdr),
+    %% ok = socket:setopt(Sock, otp, debug, false),
+    Res;
 send(#handler{socket = Sock, type = dgram}, Msg, Dest) ->
     socket:sendto(Sock, Msg, Dest).