From d6b051d9b09aeba00d1bbd0d448dde6e551c4442 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Tue, 8 May 2018 12:36:35 +0200
Subject: [socket-nif] More setopt - udp

Add setopt for one udp option: cork. This is not
platform independent. Aas fas as I know, it only works
on linux, so for now this serves as a placeholder.
---
 erts/emulator/nifs/common/socket_nif.c | 21 +++++++++++++++++++--
 erts/preloaded/src/socket.erl          | 16 ++++++++++++----
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/erts/emulator/nifs/common/socket_nif.c b/erts/emulator/nifs/common/socket_nif.c
index 9887047135..14d7cd2611 100644
--- a/erts/emulator/nifs/common/socket_nif.c
+++ b/erts/emulator/nifs/common/socket_nif.c
@@ -133,6 +133,7 @@
 #endif
 
 #include <netinet/tcp.h>
+#include <netinet/udp.h>
 #include <arpa/inet.h>
 
 #include <sys/param.h>
@@ -372,6 +373,8 @@ typedef union {
 #define SOCKET_OPT_TCP_MAXSEG      1
 #define SOCKET_OPT_TCP_NODELAY     2
 
+#define SOCKET_OPT_UDP_CORK        0
+
 #define SOCKET_OPT_SCTP_AUTOCLOSE  7
 #define SOCKET_OPT_SCTP_NODELAY    22
 
@@ -3625,8 +3628,8 @@ BOOLEAN_T eoptval2optval_tcp(ErlNifEnv*      env,
 
 
 /* +++ decode UDP socket options +++
- * Currently there are no such options, so this function
- * is just a placeholder!
+ * Currently there are only one option, cork, and that may only
+ * work on linux...
  */
 static
 BOOLEAN_T eoptval2optval_udp(ErlNifEnv*      env,
@@ -3636,6 +3639,20 @@ BOOLEAN_T eoptval2optval_udp(ErlNifEnv*      env,
                              SocketOptValue* valP)
 {
     switch (eOpt) {
+#if defined(UDP_CORK)
+    case SOCKET_OPT_UDP_CORK:
+        if (decode_bool(env, eVal, &valP->u.boolVal)) {
+            valP->tag = SOCKET_OPT_VALUE_BOOL;
+            *opt      = UDP_CORK;
+            return TRUE;
+        } else {
+            valP->tag = SOCKET_OPT_VALUE_UNDEF;
+            *opt      = -1;
+            return FALSE;
+        }
+        break;
+#endif
+
     default:
         *opt      = -1;
         valP->tag = SOCKET_OPT_VALUE_UNDEF;
diff --git a/erts/preloaded/src/socket.erl b/erts/preloaded/src/socket.erl
index 1c811fa11a..4a9de0dc9e 100644
--- a/erts/preloaded/src/socket.erl
+++ b/erts/preloaded/src/socket.erl
@@ -270,9 +270,8 @@
                               maxseg |
                               nodelay.
 
--type udp_socket_option() :: checksum |
-                             maxdgram |
-                             recvspace.
+-type udp_socket_option() :: cork.
+
 -type sctp_socket_option() ::
         adaption_layer |
         associnfo |
@@ -444,6 +443,8 @@
 -define(SOCKET_OPT_TCP_MAXSEG,          1).
 -define(SOCKET_OPT_TCP_NODELAY,         2).
 
+-define(SOCKET_OPT_UDP_CORK,            1).
+
 -define(SOCKET_OPT_SCTP_AUTOCLOSE,      7).
 -define(SOCKET_OPT_SCTP_NODELAY,        22).
 
@@ -1638,7 +1639,7 @@ enc_setopt_value(ipv6, hoplimit, V, _D, T, _P)
 enc_setopt_value(ipv6 = L, Opt, V, _D, _T, _P) ->
     not_supported({L, Opt, V});
 
-enc_setopt_value(tcp, congetsion, V, _D, T, P)
+enc_setopt_value(tcp, congestion, V, _D, T, P)
   when is_list(V) andalso
        (T =:= stream) andalso
        (P =:= tcp) ->
@@ -1656,6 +1657,11 @@ enc_setopt_value(tcp, nodelay, V, _D, T, P)
 enc_setopt_value(tcp = L, Opt, V, _D, _T, _P) ->
     not_supported({L, Opt, V});
 
+enc_setopt_value(udp, cork, V, _D, T, P)
+  when is_boolean(V) andalso
+       (T =:= dgram) andalso
+       (P =:= udp) ->
+    V;
 enc_setopt_value(udp = L, Opt, _V, _D, _T, _P) ->
     not_supported({L, Opt});
 
@@ -1940,6 +1946,8 @@ enc_sockopt_key(tcp, UnknownOpt, _Dir, _D, _T, _P) ->
     unknown(UnknownOpt);
 
 %% UDP socket options
+enc_sockopt_key(udp, cork = _Opt, _Dir, _D, _T, _P) ->
+    ?SOCKET_OPT_UDP_CORK;
 enc_sockopt_key(udp, UnknownOpt, _Dir, _D, _T, _P) ->
     unknown(UnknownOpt);
 
-- 
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