[socket-nif] Add support for socket (level sctp) option maxseg

Added support for the SCTP option MAXSEG.

OTP-14831

4 files changed, 60 insertions, 3 deletions

diff --git a/erts/doc/src/socket_usage.xml b/erts/doc/src/socket_usage.xml
index 1e325016ff..21f5d17e84 100644
--- a/erts/doc/src/socket_usage.xml
+++ b/erts/doc/src/socket_usage.xml
@@ -487,6 +487,13 @@
 	<cell>none</cell>
       </row>
       <row>
+	<cell>maxseg</cell>
+	<cell>non_neg_integer()</cell>
+	<cell>yes</cell>
+	<cell>yes</cell>
+	<cell>none</cell>
+      </row>
+      <row>
 	<cell>nodelay</cell>
 	<cell>boolean()</cell>
 	<cell>yes</cell>
diff --git a/erts/emulator/nifs/common/socket_nif.c b/erts/emulator/nifs/common/socket_nif.c
index f9643cccbf..e84eb7aa8e 100644
--- a/erts/emulator/nifs/common/socket_nif.c
+++ b/erts/emulator/nifs/common/socket_nif.c
@@ -546,6 +546,7 @@ typedef union {
 #define SOCKET_OPT_SCTP_AUTOCLOSE           8
 #define SOCKET_OPT_SCTP_DISABLE_FRAGMENTS  12
 #define SOCKET_OPT_SCTP_EVENTS             14
+#define SOCKET_OPT_SCTP_MAXSEG             21
 #define SOCKET_OPT_SCTP_NODELAY            23
 #define SOCKET_OPT_SCTP_RTOINFO            29
 
@@ -1234,6 +1235,11 @@ static ERL_NIF_TERM nsetopt_lvl_sctp_events(ErlNifEnv*        env,
                                             SocketDescriptor* descP,
                                             ERL_NIF_TERM      eVal);
 #endif
+#if defined(SCTP_MAXSEG)
+static ERL_NIF_TERM nsetopt_lvl_sctp_maxseg(ErlNifEnv*        env,
+                                            SocketDescriptor* descP,
+                                            ERL_NIF_TERM      eVal);
+#endif
 #if defined(SCTP_NODELAY)
 static ERL_NIF_TERM nsetopt_lvl_sctp_nodelay(ErlNifEnv*        env,
                                              SocketDescriptor* descP,
@@ -1459,6 +1465,10 @@ static ERL_NIF_TERM ngetopt_lvl_sctp_autoclose(ErlNifEnv*        env,
 static ERL_NIF_TERM ngetopt_lvl_sctp_disable_fragments(ErlNifEnv*        env,
                                                        SocketDescriptor* descP);
 #endif
+#if defined(SCTP_MAXSEG)
+static ERL_NIF_TERM ngetopt_lvl_sctp_maxseg(ErlNifEnv*        env,
+                                            SocketDescriptor* descP);
+#endif
 #if defined(SCTP_NODELAY)
 static ERL_NIF_TERM ngetopt_lvl_sctp_nodelay(ErlNifEnv*        env,
                                              SocketDescriptor* descP);
@@ -5575,6 +5585,12 @@ ERL_NIF_TERM nsetopt_lvl_sctp(ErlNifEnv*        env,
         break;
 #endif
 
+#if defined(SCTP_MAXSEG)
+    case SOCKET_OPT_SCTP_MAXSEG:
+        result = nsetopt_lvl_sctp_maxseg(env, descP, eVal);
+        break;
+#endif
+
 #if defined(SCTP_NODELAY)
     case SOCKET_OPT_SCTP_NODELAY:
         result = nsetopt_lvl_sctp_nodelay(env, descP, eVal);
@@ -5822,6 +5838,19 @@ ERL_NIF_TERM nsetopt_lvl_sctp_events(ErlNifEnv*        env,
 #endif
 
 
+/* nsetopt_lvl_sctp_maxseg - Level SCTP MAXSEG option
+ */
+#if defined(SCTP_MAXSEG)
+static
+ERL_NIF_TERM nsetopt_lvl_sctp_maxseg(ErlNifEnv*        env,
+                                     SocketDescriptor* descP,
+                                     ERL_NIF_TERM      eVal)
+{
+    return nsetopt_int_opt(env, descP, IPPROTO_SCTP, SCTP_MAXSEG, eVal);
+}
+#endif
+
+
 /* nsetopt_lvl_sctp_nodelay - Level SCTP NODELAY option
  */
 #if defined(SCTP_NODELAY)
@@ -7585,6 +7614,12 @@ ERL_NIF_TERM ngetopt_lvl_sctp(ErlNifEnv*        env,
         break;
 #endif
 
+#if defined(SCTP_MAXSEG)
+    case SOCKET_OPT_SCTP_MAXSEG:
+        result = ngetopt_lvl_sctp_maxseg(env, descP);
+        break;
+#endif
+
 #if defined(SCTP_NODELAY)
     case SOCKET_OPT_SCTP_NODELAY:
         result = ngetopt_lvl_sctp_nodelay(env, descP);
@@ -7697,6 +7732,18 @@ ERL_NIF_TERM ngetopt_lvl_sctp_disable_fragments(ErlNifEnv*        env,
 #endif
 
 
+/* ngetopt_lvl_sctp_maxseg - Level SCTP MAXSEG option
+ */
+#if defined(SCTP_MAXSEG)
+static
+ERL_NIF_TERM ngetopt_lvl_sctp_maxseg(ErlNifEnv*        env,
+                                     SocketDescriptor* descP)
+{
+    return ngetopt_int_opt(env, descP, IPPROTO_SCTP, SCTP_MAXSEG);
+}
+#endif
+
+
 /* ngetopt_lvl_sctp_nodelay - Level SCTP NODELAY option
  */
 #if defined(SCTP_NODELAY)
diff --git a/erts/preloaded/ebin/socket.beam b/erts/preloaded/ebin/socket.beam
index 427c08cd57..2e284e3343 100644
--- a/erts/preloaded/ebin/socket.beam
+++ b/erts/preloaded/ebin/socket.beam
diff --git a/erts/preloaded/src/socket.erl b/erts/preloaded/src/socket.erl
index 0bc3ed8ec9..1c24c75dac 100644
--- a/erts/preloaded/src/socket.erl
+++ b/erts/preloaded/src/socket.erl
@@ -670,7 +670,7 @@
 %% -define(SOCKET_OPT_SCTP_INITMSG,                18).
 %% -define(SOCKET_OPT_SCTP_I_WANT_MAPPED_V4_ADDR,  19).
 %% -define(SOCKET_OPT_SCTP_LOCAL_AUTH_CHUNKS,      20).
-%% -define(SOCKET_OPT_SCTP_MAXSEG,                 21).
+-define(SOCKET_OPT_SCTP_MAXSEG,                 21).
 %% -define(SOCKET_OPT_SCTP_MAXBURST,               22).
 -define(SOCKET_OPT_SCTP_NODELAY,                23).
 %% -define(SOCKET_OPT_SCTP_PARTIAL_DELIVERY_POINT, 24).
@@ -2229,6 +2229,9 @@ enc_setopt_value(sctp, events, #{data_in          := DataIn,
        is_boolean(SndDry)          andalso
        (P =:= sctp) ->
     V;
+enc_setopt_value(sctp, maxseg, V, _D, _T, P)
+  when is_integer(V) andalso (V >= 0) andalso (P =:= sctp) ->
+    V;
 enc_setopt_value(sctp, nodelay, V, _D, _T, P)
   when is_boolean(V) andalso (P =:= sctp) ->
     V;
@@ -2676,8 +2679,8 @@ enc_sockopt_key(sctp = L, i_want_mapped_v4_addr = Opt, _Dir, _D, _T, _P) ->
     not_supported({L, Opt});
 enc_sockopt_key(sctp = L, local_auth_chunks = Opt, _Dir, _D, _T, _P) ->
     not_supported({L, Opt});
-enc_sockopt_key(sctp = L, maxseg = Opt, _Dir, _D, _T, _P) ->
-    not_supported({L, Opt});
+enc_sockopt_key(sctp = _L, maxseg = _Opt, _Dir, _D, _T, _P) ->
+    ?SOCKET_OPT_SCTP_MAXSEG;
 enc_sockopt_key(sctp = L, maxburst = Opt, _Dir, _D, _T, _P) ->
     not_supported({L, Opt});
 enc_sockopt_key(sctp, nodelay = _Opt, _Dir, _D, _T, _P) ->