diff --git a/mio/bin/Makefile.am b/mio/bin/Makefile.am
index 95cd9f4..e15badb 100644
--- a/mio/bin/Makefile.am
+++ b/mio/bin/Makefile.am
@@ -52,3 +52,9 @@ mio_t05_SOURCES = t05.c
 mio_t05_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
 mio_t05_LDFLAGS = $(LDFLAGS_LIB_COMMON)
 mio_t05_LDADD = $(LIBADD_LIB_COMMON) -lmio $(SSL_LIBS) $(SOCKET_LIBS) $(SENDFILE_LIBS)
+
+bin_PROGRAMS += mio-t06
+mio_t06_SOURCES = t06.c
+mio_t06_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
+mio_t06_LDFLAGS = $(LDFLAGS_LIB_COMMON)
+mio_t06_LDADD = $(LIBADD_LIB_COMMON) -lmio $(SSL_LIBS) $(SOCKET_LIBS) $(SENDFILE_LIBS)
diff --git a/mio/bin/Makefile.in b/mio/bin/Makefile.in
index c7a36eb..28696c6 100644
--- a/mio/bin/Makefile.in
+++ b/mio/bin/Makefile.in
@@ -89,7 +89,8 @@ POST_UNINSTALL = :
 build_triplet = @build@
 host_triplet = @host@
 bin_PROGRAMS = mio-execd$(EXEEXT) mio-t01$(EXEEXT) mio-t02$(EXEEXT) \
-	mio-t03$(EXEEXT) mio-t04$(EXEEXT) mio-t05$(EXEEXT)
+	mio-t03$(EXEEXT) mio-t04$(EXEEXT) mio-t05$(EXEEXT) \
+	mio-t06$(EXEEXT)
 subdir = bin
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/ax_check_sign.m4 \
@@ -155,6 +156,13 @@ mio_t05_DEPENDENCIES = $(am__DEPENDENCIES_2) $(am__DEPENDENCIES_1) \
 mio_t05_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
 	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
 	$(mio_t05_LDFLAGS) $(LDFLAGS) -o $@
+am_mio_t06_OBJECTS = mio_t06-t06.$(OBJEXT)
+mio_t06_OBJECTS = $(am_mio_t06_OBJECTS)
+mio_t06_DEPENDENCIES = $(am__DEPENDENCIES_2) $(am__DEPENDENCIES_1) \
+	$(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1)
+mio_t06_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(mio_t06_LDFLAGS) $(LDFLAGS) -o $@
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
 am__v_P_0 = false
@@ -173,7 +181,7 @@ am__maybe_remake_depfiles = depfiles
 am__depfiles_remade = ./$(DEPDIR)/mio_execd-execd.Po \
 	./$(DEPDIR)/mio_t01-t01.Po ./$(DEPDIR)/mio_t02-t02.Po \
 	./$(DEPDIR)/mio_t03-t03.Po ./$(DEPDIR)/mio_t04-t04.Po \
-	./$(DEPDIR)/mio_t05-t05.Po
+	./$(DEPDIR)/mio_t05-t05.Po ./$(DEPDIR)/mio_t06-t06.Po
 am__mv = mv -f
 COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
 	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
@@ -194,10 +202,11 @@ am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
 am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
 SOURCES = $(mio_execd_SOURCES) $(mio_t01_SOURCES) $(mio_t02_SOURCES) \
-	$(mio_t03_SOURCES) $(mio_t04_SOURCES) $(mio_t05_SOURCES)
+	$(mio_t03_SOURCES) $(mio_t04_SOURCES) $(mio_t05_SOURCES) \
+	$(mio_t06_SOURCES)
 DIST_SOURCES = $(mio_execd_SOURCES) $(mio_t01_SOURCES) \
 	$(mio_t02_SOURCES) $(mio_t03_SOURCES) $(mio_t04_SOURCES) \
-	$(mio_t05_SOURCES)
+	$(mio_t05_SOURCES) $(mio_t06_SOURCES)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
     n|no|NO) false;; \
@@ -411,6 +420,10 @@ mio_t05_SOURCES = t05.c
 mio_t05_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
 mio_t05_LDFLAGS = $(LDFLAGS_LIB_COMMON)
 mio_t05_LDADD = $(LIBADD_LIB_COMMON) -lmio $(SSL_LIBS) $(SOCKET_LIBS) $(SENDFILE_LIBS)
+mio_t06_SOURCES = t06.c
+mio_t06_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
+mio_t06_LDFLAGS = $(LDFLAGS_LIB_COMMON)
+mio_t06_LDADD = $(LIBADD_LIB_COMMON) -lmio $(SSL_LIBS) $(SOCKET_LIBS) $(SENDFILE_LIBS)
 all: all-am
 
 .SUFFIXES:
@@ -518,6 +531,10 @@ mio-t05$(EXEEXT): $(mio_t05_OBJECTS) $(mio_t05_DEPENDENCIES) $(EXTRA_mio_t05_DEP
 	@rm -f mio-t05$(EXEEXT)
 	$(AM_V_CCLD)$(mio_t05_LINK) $(mio_t05_OBJECTS) $(mio_t05_LDADD) $(LIBS)
 
+mio-t06$(EXEEXT): $(mio_t06_OBJECTS) $(mio_t06_DEPENDENCIES) $(EXTRA_mio_t06_DEPENDENCIES) 
+	@rm -f mio-t06$(EXEEXT)
+	$(AM_V_CCLD)$(mio_t06_LINK) $(mio_t06_OBJECTS) $(mio_t06_LDADD) $(LIBS)
+
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
 
@@ -530,6 +547,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mio_t03-t03.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mio_t04-t04.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mio_t05-t05.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mio_t06-t06.Po@am__quote@ # am--include-marker
 
 $(am__depfiles_remade):
 	@$(MKDIR_P) $(@D)
@@ -645,6 +663,20 @@ mio_t05-t05.obj: t05.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(mio_t05_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o mio_t05-t05.obj `if test -f 't05.c'; then $(CYGPATH_W) 't05.c'; else $(CYGPATH_W) '$(srcdir)/t05.c'; fi`
 
+mio_t06-t06.o: t06.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(mio_t06_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT mio_t06-t06.o -MD -MP -MF $(DEPDIR)/mio_t06-t06.Tpo -c -o mio_t06-t06.o `test -f 't06.c' || echo '$(srcdir)/'`t06.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/mio_t06-t06.Tpo $(DEPDIR)/mio_t06-t06.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='t06.c' object='mio_t06-t06.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(mio_t06_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o mio_t06-t06.o `test -f 't06.c' || echo '$(srcdir)/'`t06.c
+
+mio_t06-t06.obj: t06.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(mio_t06_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT mio_t06-t06.obj -MD -MP -MF $(DEPDIR)/mio_t06-t06.Tpo -c -o mio_t06-t06.obj `if test -f 't06.c'; then $(CYGPATH_W) 't06.c'; else $(CYGPATH_W) '$(srcdir)/t06.c'; fi`
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/mio_t06-t06.Tpo $(DEPDIR)/mio_t06-t06.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='t06.c' object='mio_t06-t06.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(mio_t06_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o mio_t06-t06.obj `if test -f 't06.c'; then $(CYGPATH_W) 't06.c'; else $(CYGPATH_W) '$(srcdir)/t06.c'; fi`
+
 mostlyclean-libtool:
 	-rm -f *.lo
 
@@ -784,6 +816,7 @@ distclean: distclean-am
 	-rm -f ./$(DEPDIR)/mio_t03-t03.Po
 	-rm -f ./$(DEPDIR)/mio_t04-t04.Po
 	-rm -f ./$(DEPDIR)/mio_t05-t05.Po
+	-rm -f ./$(DEPDIR)/mio_t06-t06.Po
 	-rm -f Makefile
 distclean-am: clean-am distclean-compile distclean-generic \
 	distclean-tags
@@ -835,6 +868,7 @@ maintainer-clean: maintainer-clean-am
 	-rm -f ./$(DEPDIR)/mio_t03-t03.Po
 	-rm -f ./$(DEPDIR)/mio_t04-t04.Po
 	-rm -f ./$(DEPDIR)/mio_t05-t05.Po
+	-rm -f ./$(DEPDIR)/mio_t06-t06.Po
 	-rm -f Makefile
 maintainer-clean-am: distclean-am maintainer-clean-generic
 
diff --git a/mio/bin/t01.c b/mio/bin/t01.c
index 7785b47..9f24d34 100644
--- a/mio/bin/t01.c
+++ b/mio/bin/t01.c
@@ -969,7 +969,7 @@ if (mio_htre_getcontentlen(req) > 0)
 			else if (mio_comp_bcstr_limited(qpath, "/cgi/", 5, 1) == 0)
 				x = mio_svc_htts_docgi(htts, csck, req, "", mio_htre_getqpath(req));
 			else
-				x = mio_svc_htts_dofile(htts, csck, req, "", mio_htre_getqpath(req));
+				x = mio_svc_htts_dofile(htts, csck, req, "", mio_htre_getqpath(req), "text/plain");
 			if (x <= -1) goto oops;
 
 	return 0;
diff --git a/mio/configure b/mio/configure
index 2aa954b..a610b26 100755
--- a/mio/configure
+++ b/mio/configure
@@ -17924,7 +17924,7 @@ _ACEOF
 fi
 done
 
-for ac_func in accept4 sendmsg recvmsg writev readv
+for ac_func in pipe2 accept4 sendmsg recvmsg writev readv
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/mio/configure.ac b/mio/configure.ac
index 3781d03..4145a14 100644
--- a/mio/configure.ac
+++ b/mio/configure.ac
@@ -160,7 +160,7 @@ AC_CHECK_FUNCS([backtrace backtrace_symbols])
 AC_CHECK_FUNCS([fork vfork posix_spawn gettid nanosleep select])
 AC_CHECK_FUNCS([makecontext swapcontext getcontext setcontext])
 AC_CHECK_FUNCS([snprintf _vsnprintf _vsnwprintf])
-AC_CHECK_FUNCS([accept4 sendmsg recvmsg writev readv])
+AC_CHECK_FUNCS([pipe2 accept4 sendmsg recvmsg writev readv])
 AC_CHECK_FUNCS([isatty mmap munmap])
 
 OLDLIBS="$LIBS"
diff --git a/mio/lib/http-fil.c b/mio/lib/http-fil.c
index 75e73d9..163326f 100644
--- a/mio/lib/http-fil.c
+++ b/mio/lib/http-fil.c
@@ -444,7 +444,7 @@ static mio_htrd_recbs_t file_client_htrd_recbs =
 
 /* --------------------------------------------------------------------- */
 
-static int file_state_send_header_to_client (file_state_t* file_state, int status_code, int force_close)
+static int file_state_send_header_to_client (file_state_t* file_state, int status_code, int force_close, const mio_bch_t* mime_type)
 {
 	mio_svc_htts_cli_t* cli = file_state->client;
 	mio_bch_t dtbuf[64];
@@ -457,11 +457,11 @@ static int file_state_send_header_to_client (file_state_t* file_state, int statu
 	content_length = file_state->end_offset - file_state->start_offset + 1;
 	if (status_code == 200 && file_state->total_size != content_length) status_code = 206;
 
-	if (mio_becs_fmt(cli->sbuf, "HTTP/%d.%d %d %hs\r\nServer: %hs\r\nDate: %s\r\nConnection: %hs\r\nAccept-Ranges: bytes\r\n",
+	if (mio_becs_fmt(cli->sbuf, "HTTP/%d.%d %d %hs\r\nServer: %hs\r\nDate: %s\r\nConnection: %hs\r\nAccept-Ranges: bytes\r\nContent-Type: %hs\r\n",
 		file_state->req_version.major, file_state->req_version.minor,
 		status_code, mio_http_status_to_bcstr(status_code),
 		cli->htts->server_name, dtbuf,
-		(force_close? "close": "keep-alive")) == (mio_oow_t)-1) return -1;
+		(force_close? "close": "keep-alive"), mime_type) == (mio_oow_t)-1) return -1;
 
 /* TODO: content_type */
 
@@ -687,7 +687,7 @@ static MIO_INLINE void fadvise_on_peer (file_state_t* file_state)
 #endif
 }
 
-int mio_svc_htts_dofile (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t* req, const mio_bch_t* docroot, const mio_bch_t* file)
+int mio_svc_htts_dofile (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t* req, const mio_bch_t* docroot, const mio_bch_t* file, const mio_bch_t* mime_type)
 {
 /* TODO: ETag, Last-Modified... */
 
@@ -824,14 +824,13 @@ int mio_svc_htts_dofile (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t*
 			mio_dev_sck_setsockopt(file_state->client->sck, SOL_TCP, TCP_CORK, &tcp_cork, MIO_SIZEOF(tcp_cork));
 		#endif
 
-			if (file_state_send_header_to_client(file_state, 200, 0) <= -1 ||
+			if (file_state_send_header_to_client(file_state, 200, 0, mime_type) <= -1 ||
 			    file_state_send_contents_to_client(file_state) <= -1) goto oops;
 		}
 	}
 	else if (file_state->req_method == MIO_HTTP_HEAD)
 	{
-
-		if (file_state_send_header_to_client(file_state, 200, 0) <= -1) goto oops;
+		if (file_state_send_header_to_client(file_state, 200, 0, mime_type) <= -1) goto oops;
 		file_state_mark_over (file_state, FILE_STATE_OVER_READ_FROM_PEER | FILE_STATE_OVER_WRITE_TO_PEER);
 	}
 
diff --git a/mio/lib/http-svr.c b/mio/lib/http-svr.c
index 0a5e4e6..110d8f5 100644
--- a/mio/lib/http-svr.c
+++ b/mio/lib/http-svr.c
@@ -25,6 +25,7 @@
  */
 
 #include "http-prv.h"
+#include <mio-path.h>
 
 /* ------------------------------------------------------------------------ */
 static int client_htrd_peek_request (mio_htrd_t* htrd, mio_htre_t* req)
@@ -482,3 +483,9 @@ mio_bch_t* mio_svc_htts_dupmergepaths (mio_svc_htts_t* htts, const mio_bch_t* ba
 	return xpath;
 }
 
+int mio_svc_htts_writetosidechan (mio_svc_htts_t* htts, const void* dptr, mio_oow_t dlen)
+{
+	return mio_dev_sck_writetosidechan(htts->lsck, dptr, dlen);
+}
+
+
diff --git a/mio/lib/mio-cfg.h.in b/mio/lib/mio-cfg.h.in
index 7d2f770..7684a8f 100644
--- a/mio/lib/mio-cfg.h.in
+++ b/mio/lib/mio-cfg.h.in
@@ -376,6 +376,9 @@
 /* Define to 1 if you have the <openssl/ssl.h> header file. */
 #undef HAVE_OPENSSL_SSL_H
 
+/* Define to 1 if you have the `pipe2' function. */
+#undef HAVE_PIPE2
+
 /* Define to 1 if you have the `posix_fadvise' function. */
 #undef HAVE_POSIX_FADVISE
 
diff --git a/mio/lib/mio-http.h b/mio/lib/mio-http.h
index 74e162a..7a23ea4 100644
--- a/mio/lib/mio-http.h
+++ b/mio/lib/mio-http.h
@@ -264,6 +264,12 @@ static MIO_INLINE mio_t* mio_svc_htts_getmio(mio_svc_htts_t* svc) { return mio_s
 #	define mio_svc_htts_getmio(svc) mio_svc_getmio(svc)
 #endif
 
+MIO_EXPORT int mio_svc_htts_writetosidechan (
+	mio_svc_htts_t* htts,
+	const void*     dptr,
+	mio_oow_t       dlen
+);
+
 MIO_EXPORT int mio_svc_htts_setservernamewithbcstr (
 	mio_svc_htts_t*  htts,
 	const mio_bch_t* server_name
@@ -282,7 +288,8 @@ MIO_EXPORT int mio_svc_htts_dofile (
 	mio_dev_sck_t*   csck,
 	mio_htre_t*      req,
 	const mio_bch_t* docroot,
-	const mio_bch_t* script
+	const mio_bch_t* file,
+	const mio_bch_t* mime_type
 );
 
 MIO_EXPORT int mio_svc_htts_dothr (
diff --git a/mio/lib/mio-prv.h b/mio/lib/mio-prv.h
index 3325cc0..1954b4d 100644
--- a/mio/lib/mio-prv.h
+++ b/mio/lib/mio-prv.h
@@ -114,6 +114,11 @@ int mio_makesyshndasync (
 	mio_syshnd_t hnd
 );
 
+int mio_makesyshndcloexec (
+	mio_t*       mio,
+	mio_syshnd_t hnd
+);
+
 void mio_cleartmrjobs (
 	mio_t* mio
 );
diff --git a/mio/lib/mio-sck.h b/mio/lib/mio-sck.h
index 3d10fac..50c9f4d 100644
--- a/mio/lib/mio-sck.h
+++ b/mio/lib/mio-sck.h
@@ -186,23 +186,6 @@ typedef struct mio_icmphdr_t mio_icmphdr_t;
 	typedef int mio_scklen_t;
 #endif
 
-#if defined(_WIN32)
-#	define MIO_IOCP_KEY 1
-	/*
-	typedef HANDLE mio_syshnd_t;
-	typedef SOCKET mio_sckhnd_t;
-#	define MIO_SCKHND_INVALID (INVALID_SOCKET)
-	*/
-
-	typedef mio_uintptr_t mio_sckhnd_t;
-#	define MIO_SCKHND_INVALID (~(mio_sck_hnd_t)0)
-
-#else
-	typedef int mio_sckhnd_t;
-#	define MIO_SCKHND_INVALID (-1)
-	
-#endif
-
 
 /* ========================================================================= */
 
@@ -270,8 +253,16 @@ typedef void (*mio_dev_sck_on_connect_t) (
 	mio_dev_sck_t* dev
 );
 
+typedef void (*mio_dev_sck_on_raw_accept_t) (
+	mio_dev_sck_t* dev,
+	mio_syshnd_t   syshnd
+);
+
 enum mio_dev_sck_type_t
 {
+	MIO_DEV_SCK_QX,
+
+
 	MIO_DEV_SCK_TCP4,
 	MIO_DEV_SCK_TCP6,
 	MIO_DEV_SCK_UDP4,
@@ -285,22 +276,33 @@ enum mio_dev_sck_type_t
 	MIO_DEV_SCK_ICMP4,
 
 	/* ICMP at the IPv6 layer */
-	MIO_DEV_SCK_ICMP6
+	MIO_DEV_SCK_ICMP6,
 
-#if 0
-	MIO_DEV_SCK_RAW,  /* raw L2-level packet */
-#endif
+	/* raw L2-level packet */
+	MIO_DEV_SCK_PACKET
 };
 typedef enum mio_dev_sck_type_t mio_dev_sck_type_t;
 
+enum mio_dev_sck_make_option_t
+{
+	/* import the system handle specified in the hnd field */
+	MIO_DEV_SCK_MAKE_IMPSYSHND = (1 << 0) 
+};
+typedef enum mio_dev_sck_make_option_t mio_dev_sck_make_option_t;
+
 typedef struct mio_dev_sck_make_t mio_dev_sck_make_t;
 struct mio_dev_sck_make_t
 {
 	mio_dev_sck_type_t type;
+
+	int options;
+	mio_syshnd_t syshnd;
+
 	mio_dev_sck_on_write_t on_write;
 	mio_dev_sck_on_read_t on_read;
 	mio_dev_sck_on_connect_t on_connect;
 	mio_dev_sck_on_disconnect_t on_disconnect;
+	mio_dev_sck_on_raw_accept_t on_raw_accept; /* optional */
 };
 
 enum mio_dev_sck_bind_option_t
@@ -362,7 +364,7 @@ struct mio_dev_sck_t
 	MIO_DEV_HEADER;
 
 	mio_dev_sck_type_t type;
-	mio_sckhnd_t hnd;
+	mio_syshnd_t hnd;
 
 	int state;
 
@@ -387,11 +389,11 @@ struct mio_dev_sck_t
 	mio_dev_sck_on_write_t on_write;
 	mio_dev_sck_on_read_t on_read;
 
-	/* return 0 on succes, -1 on failure.
-	 * called on a new tcp device for an accepted client or
+	/* called on a new tcp device for an accepted client or
 	 *        on a tcp device conntected to a remote server */
 	mio_dev_sck_on_connect_t on_connect;
 	mio_dev_sck_on_disconnect_t on_disconnect;
+	mio_dev_sck_on_raw_accept_t on_raw_accept;
 
 	/* timer job index for handling
 	 *  - connect() timeout for a connecting socket.
@@ -406,6 +408,7 @@ struct mio_dev_sck_t
 	void* ssl_ctx;
 	void* ssl;
 
+	mio_syshnd_t side_chan; /* side-channel for MIO_DEV_SCK_QX */
 };
 
 enum mio_dev_sck_shutdown_how_t
@@ -415,15 +418,26 @@ enum mio_dev_sck_shutdown_how_t
 };
 typedef enum mio_dev_sck_shutdown_how_t mio_dev_sck_shutdown_how_t;
 
+enum mio_dev_sck_qxmsg_cmd_t
+{
+	MIO_DEV_SCK_QXMSG_NEWCONN = 0
+};
+typedef enum mio_dev_sck_qxmsg_cmd_t mio_dev_sck_qxmsg_cmd_t;
+
+struct mio_dev_sck_qxmsg_t
+{
+	mio_dev_sck_qxmsg_cmd_t cmd;
+	mio_dev_sck_type_t scktype;
+	mio_syshnd_t syshnd;
+	mio_skad_t remoteaddr;
+};
+typedef struct mio_dev_sck_qxmsg_t mio_dev_sck_qxmsg_t;
+
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-MIO_EXPORT int mio_makesckasync (
-	mio_t*       mio,
-	mio_sckhnd_t sck
-);
-
 /* ========================================================================= */
 
 MIO_EXPORT mio_dev_sck_t* mio_dev_sck_make (
@@ -434,14 +448,14 @@ MIO_EXPORT mio_dev_sck_t* mio_dev_sck_make (
 
 #if defined(MIO_HAVE_INLINE)
 static MIO_INLINE mio_t* mio_dev_sck_getmio (mio_dev_sck_t* sck) { return mio_dev_getmio((mio_dev_t*)sck); }
+static MIO_INLINE void* mio_dev_sck_getxtn (mio_dev_sck_t* sck) { return (void*)(sck + 1); }
+static MIO_INLINE mio_dev_sck_type_t mio_dev_sck_gettype (mio_dev_sck_t* sck) { return sck->type; }
+static MIO_INLINE mio_syshnd_t mio_dev_sck_getsyshnd (mio_dev_sck_t* sck) { return sck->hnd; }
 #else
 #	define mio_dev_sck_getmio(sck) mio_dev_getmio(sck)
-#endif
-
-#if defined(MIO_HAVE_INLINE)
-static MIO_INLINE void* mio_dev_sck_getxtn (mio_dev_sck_t* sck) { return (void*)(sck + 1); }
-#else
 #	define mio_dev_sck_getxtn(sck) ((void*)(((mio_dev_sck_t*)sck) + 1))
+#	define mio_dev_sck_gettype(sck) (((mio_dev_sck_t*)sck)->type)
+#	define mio_dev_sck_getsyshnd(sck) (((mio_dev_sck_t*)sck)->hnd)
 #endif
 
 MIO_EXPORT int mio_dev_sck_bind (
@@ -566,9 +580,16 @@ MIO_EXPORT int mio_dev_sck_sendfileok (
 	mio_dev_sck_t* dev
 );
 
+MIO_EXPORT int mio_dev_sck_writetosidechan (
+	mio_dev_sck_t* htts,
+	const void*    dptr,
+	mio_oow_t      dlen
+);
+
+
 MIO_EXPORT mio_uint16_t mio_checksum_ip (
 	const void* hdr,
-	mio_oow_t len
+	mio_oow_t   len
 );
 
 #ifdef __cplusplus
diff --git a/mio/lib/sck.c b/mio/lib/sck.c
index a67379d..75c24d7 100644
--- a/mio/lib/sck.c
+++ b/mio/lib/sck.c
@@ -35,6 +35,7 @@
 
 #include <netinet/in.h>
 #include <arpa/inet.h>
+#include <netinet/if_ether.h>
 
 #if defined(HAVE_NETPACKET_PACKET_H)
 #	include <netpacket/packet.h>
@@ -78,28 +79,22 @@
 
 /* ========================================================================= */
 
-int mio_makesckasync (mio_t* mio, mio_sckhnd_t sck)
-{
-	return mio_makesyshndasync (mio, (mio_syshnd_t)sck);
-}
-
-static void close_async_socket (mio_t* mio, mio_sckhnd_t sck)
+static void close_async_socket (mio_t* mio, mio_syshnd_t sck)
 {
 	close (sck);
 }
 
-static mio_sckhnd_t open_async_socket (mio_t* mio, int domain, int type, int proto)
+static mio_syshnd_t open_async_socket (mio_t* mio, int domain, int type, int proto)
 {
-	mio_sckhnd_t sck = MIO_SCKHND_INVALID;
+	mio_syshnd_t sck = MIO_SYSHND_INVALID;
 	int flags;
 
 #if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
-	type |= SOCK_NONBLOCK;
-	type |= SOCK_CLOEXEC;
+	type |= SOCK_NONBLOCK | SOCK_CLOEXEC;
 open_socket:
 #endif
 	sck = socket(domain, type, proto); 
-	if (sck == MIO_SCKHND_INVALID) 
+	if (sck == MIO_SYSHND_INVALID) 
 	{
 	#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
 		if (errno == EINVAL && (type & (SOCK_NONBLOCK | SOCK_CLOEXEC)))
@@ -117,23 +112,96 @@ open_socket:
 	#endif
 	}
 
-	flags = fcntl(sck, F_GETFD, 0);
-	if (flags == -1) goto oops;
-#if defined(FD_CLOEXEC)
-	flags |= FD_CLOEXEC;
-#endif
-#if defined(O_NONBLOCK)
-	flags |= O_NONBLOCK;
-#endif
-	if (fcntl(sck, F_SETFD, flags) == -1) goto oops;
+	if (mio_makesyshndasync(mio, sck) <= -1 ||
+	    mio_makesyshndcloexec(mio, sck) <= -1) goto oops;
 
 done:
 	return sck;
 
 oops:
-	if (sck != MIO_SCKHND_INVALID) close (sck);
+	if (sck != MIO_SYSHND_INVALID) close (sck);
 	mio_seterrwithsyserr (mio, 0, errno);
-	return MIO_SCKHND_INVALID;
+	return MIO_SYSHND_INVALID;
+}
+
+static mio_syshnd_t open_async_qx (mio_t* mio, mio_syshnd_t* side_chan)
+{
+	int fd[2];
+
+#if 1
+	int type = SOCK_DGRAM;
+
+#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
+	type |= SOCK_NONBLOCK | SOCK_CLOEXEC;
+open_socket:
+#endif
+	if (socketpair(AF_UNIX, type, 0, fd) <= -1)
+	{
+	#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
+		if (errno == EINVAL && (type & (SOCK_NONBLOCK | SOCK_CLOEXEC)))
+		{
+			type &= ~(SOCK_NONBLOCK | SOCK_CLOEXEC);
+			goto open_socket;
+		}
+	#endif
+		return MIO_SYSHND_INVALID;
+	}
+	else
+	{
+	#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
+		if (type & (SOCK_NONBLOCK | SOCK_CLOEXEC)) goto done;
+	#endif
+	}
+
+	if (mio_makesyshndasync(mio, fd[0]) <= -1 ||
+	    mio_makesyshndasync(mio, fd[1]) <= -1 ||
+	    mio_makesyshndcloexec(mio, fd[0]) <= -1 ||
+	    mio_makesyshndcloexec(mio, fd[1]) <= -1) 
+	{
+		close (fd[0]);
+		close (fd[1]);
+		return MIO_SYSHND_INVALID;
+	}
+
+done:
+	*side_chan = fd[1]; /* write end of the pipe */
+	return fd[0]; /* read end of the pipe */
+#else
+
+#if defined(HAVE_PIPE2)
+	/* in linux 3.4 or higher, O_DIRECT can make the pipes work in the packet mode if the data size is <= PIPE_BUF */
+	if (pipe2(fd, O_CLOEXEC | O_NONBLOCK) <= -1)
+	{
+		if  (errno == ENOSYS) goto normal_pipe;
+		mio_seterrwithsyserr (mio, 0, errno);
+		return MIO_SYSHND_INVALID;
+	}
+	goto done;
+
+normal_pipe:
+#endif
+	if (pipe(fd) <= -1)
+	{
+		mio_seterrwithsyserr (mio, 0, errno);
+		return MIO_SYSHND_INVALID;
+	}
+
+	if (mio_makesyshndasync(mio, fd[0]) <= -1 ||
+	    mio_makesyshndasync(mio, fd[1]) <= -1 ||
+	    mio_makesyshndcloexec(mio, fd[0]) <= -1 ||
+	    mio_makesyshndcloexec(mio, fd[1]) <= -1) 
+	{
+		close (fd[0]);
+		close (fd[1]);
+		return MIO_SYSHND_INVALID;
+	}
+
+#if defined(HAVE_PIPE2)
+done:
+#endif
+	*side_chan = fd[1]; /* write end of the pipe */
+	return fd[0]; /* read end of the pipe */
+#endif
 }
 
 /* ========================================================================= */
@@ -167,8 +235,13 @@ struct sck_type_map_t
 	int extra_dev_cap;
 };
 
+#define __AF_QX 999999
+
 static struct sck_type_map_t sck_type_map[] =
 {
+	/* MIO_DEV_SCK_QX */
+	{ __AF_QX,    0,              0,                         0 },
+
 	/* MIO_DEV_SCK_TCP4 */
 	{ AF_INET,    SOCK_STREAM,    0,                         MIO_DEV_CAP_STREAM },
 
@@ -176,10 +249,10 @@ static struct sck_type_map_t sck_type_map[] =
 	{ AF_INET6,   SOCK_STREAM,    0,                         MIO_DEV_CAP_STREAM },
 
 	/* MIO_DEV_SCK_UPD4 */
-	{ AF_INET,    SOCK_DGRAM,     0,                         0                                                },
+	{ AF_INET,    SOCK_DGRAM,     0,                         0                                             },
 
 	/* MIO_DEV_SCK_UDP6 */
-	{ AF_INET6,   SOCK_DGRAM,     0,                         0                                                },
+	{ AF_INET6,   SOCK_DGRAM,     0,                         0                                             },
 
 
 #if defined(AF_PACKET) && (MIO_SIZEOF_STRUCT_SOCKADDR_LL > 0)
@@ -196,15 +269,26 @@ static struct sck_type_map_t sck_type_map[] =
 	/* MIO_DEV_SCK_ARP_DGRAM */
 	{ AF_LINK,  SOCK_DGRAM,       MIO_CONST_HTON16(MIO_ETHHDR_PROTO_ARP), 0                                 },
 #else
-	{ -1,       0,                0,                            0                                             },
-	{ -1,       0,                0,                            0                                             },
+	{ -1,       0,                0,                         0                                              },
+	{ -1,       0,                0,                         0                                              },
 #endif
 
 	/* MIO_DEV_SCK_ICMP4 - IP protocol field is 1 byte only. no byte order conversion is needed */
-	{ AF_INET,    SOCK_RAW,       IPPROTO_ICMP,              0,                                               },
+	{ AF_INET,    SOCK_RAW,       IPPROTO_ICMP,              0,                                             },
 
 	/* MIO_DEV_SCK_ICMP6 - IP protocol field is 1 byte only. no byte order conversion is needed */
-	{ AF_INET6,   SOCK_RAW,       IPPROTO_ICMP,              0,                                               }
+	{ AF_INET6,   SOCK_RAW,       IPPROTO_ICMP,              0,                                             },
+
+
+#if defined(AF_PACKET) && (MIO_SIZEOF_STRUCT_SOCKADDR_LL > 0)
+	/* MIO_DEV_SCK_PACKET */
+	{ AF_PACKET,  SOCK_RAW,       MIO_CONST_HTON16(ETH_P_ALL),            0                                 },
+#elif defined(AF_LINK) && (MIO_SIZEOF_STRUCT_SOCKADDR_DL > 0)
+	/* MIO_DEV_SCK_PACKET */
+	{ AF_PACKET,  SOCK_RAW,       MIO_CONST_HTON16(ETH_P_ALL),            0                                 },
+#else
+	{ -1,       0,                0,                         0                                              },
+#endif
 };
 
 /* ======================================================================== */
@@ -294,6 +378,8 @@ static int dev_sck_make (mio_dev_t* dev, void* ctx)
 	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 	mio_dev_sck_make_t* arg = (mio_dev_sck_make_t*)ctx;
+	mio_syshnd_t hnd = MIO_SYSHND_INVALID;
+	mio_syshnd_t side_chan = MIO_SYSHND_INVALID;
 
 	MIO_ASSERT (mio, arg->type >= 0 && arg->type < MIO_COUNTOF(sck_type_map));
 
@@ -303,9 +389,38 @@ static int dev_sck_make (mio_dev_t* dev, void* ctx)
 		return -1;
 	}
 
-	rdev->hnd = open_async_socket(mio, sck_type_map[arg->type].domain, sck_type_map[arg->type].type, sck_type_map[arg->type].proto);
-	if (rdev->hnd == MIO_SCKHND_INVALID) goto oops;
+	if (arg->options & MIO_DEV_SCK_MAKE_IMPSYSHND)
+	{
+		/* Make sure to pass a proper type for a given socket handle when you use MIO_DEV_SCK_MAKE_IMPSYSHND.
+		 * Otherwise, some innerworking of the library may go wrong */
+		if (sck_type_map[arg->type].domain == __AF_QX)
+		{
+			/* can't import a handle of this type */
+			mio_seterrnum (mio, MIO_EINVAL); 
+			goto oops;
+		}
 
+		hnd = arg->syshnd;
+		if (hnd == MIO_SYSHND_INVALID)
+		{
+			mio_seterrnum (mio, MIO_EINVAL); 
+			goto oops;
+		}
+		if (mio_makesyshndasync(mio, hnd) <= -1) goto oops;
+	}
+	else if (sck_type_map[arg->type].domain == __AF_QX)
+	{
+		hnd = open_async_qx(mio, &side_chan);
+		if (hnd == MIO_SYSHND_INVALID) goto oops;
+	}
+	else
+	{
+		hnd = open_async_socket(mio, sck_type_map[arg->type].domain, sck_type_map[arg->type].type, sck_type_map[arg->type].proto);
+		if (hnd == MIO_SYSHND_INVALID) goto oops;
+	}
+
+	rdev->hnd = hnd;
+	rdev->side_chan = side_chan;
 	rdev->dev_cap = MIO_DEV_CAP_IN | MIO_DEV_CAP_OUT | sck_type_map[arg->type].extra_dev_cap;
 	rdev->on_write = arg->on_write;
 	rdev->on_read = arg->on_read;
@@ -317,11 +432,8 @@ static int dev_sck_make (mio_dev_t* dev, void* ctx)
 	return 0;
 
 oops:
-	if (rdev->hnd != MIO_SCKHND_INVALID)
-	{
-		close_async_socket (mio, rdev->hnd);
-		rdev->hnd = MIO_SCKHND_INVALID;
-	}
+	if (hnd != MIO_SYSHND_INVALID) close_async_socket (mio, hnd);
+	if (side_chan != MIO_SYSHND_INVALID) close (rdev->side_chan);
 	return -1;
 }
 
@@ -340,18 +452,8 @@ static int dev_sck_make_client (mio_dev_t* dev, void* ctx)
 	rdev->hnd = *clisckhnd;
 	rdev->tmrjob_index = MIO_TMRIDX_INVALID;
 
-	if (mio_makesckasync(mio, rdev->hnd) <= -1) return -1;
-#if defined(FD_CLOEXEC)
-	{
-		int flags = fcntl(rdev->hnd, F_GETFD, 0);
-		if (fcntl(rdev->hnd, F_SETFD, flags | FD_CLOEXEC) == -1)
-		{
-			mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to set FD_CLOEXEC");
-			return -1;
-		}
-	}
-#endif
-
+	if (mio_makesyshndasync(mio, rdev->hnd) <= -1 ||
+	    mio_makesyshndcloexec(mio, rdev->hnd) <= -1) return -1;
 	return 0;
 }
 
@@ -398,12 +500,17 @@ static int dev_sck_kill (mio_dev_t* dev, int force)
 	}
 #endif
 
-	if (rdev->hnd != MIO_SCKHND_INVALID) 
+	if (rdev->hnd != MIO_SYSHND_INVALID) 
 	{
 		close_async_socket (mio, rdev->hnd);
-		rdev->hnd = MIO_SCKHND_INVALID;
+		rdev->hnd = MIO_SYSHND_INVALID;
 	}
 
+	if (rdev->side_chan != MIO_SYSHND_INVALID)
+	{
+		close (rdev->hnd);
+		rdev->hnd = MIO_SYSHND_INVALID;
+	}
 	return 0;
 }
 
@@ -1255,6 +1362,7 @@ static mio_dev_mth_t dev_mth_clisck =
 	dev_sck_sendfile_stateful,
 	dev_sck_ioctl
 };
+
 /* ========================================================================= */
 
 static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
@@ -1349,55 +1457,23 @@ static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 	}
 }
 
-static int accept_incoming_connection (mio_dev_sck_t* rdev)
+static int make_accepted_client_connection (mio_dev_sck_t* rdev, mio_syshnd_t clisck, mio_skad_t* remoteaddr)
 {
 	mio_t* mio = rdev->mio;
-	mio_sckhnd_t clisck;
-	mio_skad_t remoteaddr;
-	mio_scklen_t addrlen;
 	mio_dev_sck_t* clidev;
-	int flags;
+	mio_scklen_t addrlen;
 
-	/* this is a server(lisening) socket */
-
-#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC) && defined(HAVE_ACCEPT4)
-	flags = SOCK_NONBLOCK | SOCK_CLOEXEC;
-
-	addrlen = MIO_SIZEOF(remoteaddr);
-	clisck = accept4(rdev->hnd, (struct sockaddr*)&remoteaddr, &addrlen, flags);
-	if (clisck == MIO_SCKHND_INVALID)
+	if (rdev->on_raw_accept)
 	{
-		 if (errno != ENOSYS)
-		 {
-			if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;
-			if (errno == EINTR) return 0; /* if interrupted by a signal, treat it as if it's EINPROGRESS */
-
-			mio_seterrwithsyserr (mio, 0, errno);
-			return -1;
-		 }
-
-		 // go on for the normal 3-parameter accept
-	}
-	else
-	{
-		 goto accept_done;
+		/* this is a special optional callback. If you don't want a client socket device 
+		 * to be created upon accept, you may implement the on_raw_accept() handler. 
+		 * the socket handle is delated to the callback. */
+		rdev->on_raw_accept (rdev, clisck);
+		return 0;
 	}
 
-#endif
-	addrlen = MIO_SIZEOF(remoteaddr);
-	clisck = accept(rdev->hnd, (struct sockaddr*)&remoteaddr, &addrlen);
-	if (clisck == MIO_SCKHND_INVALID)
-	{
-		if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;
-		if (errno == EINTR) return 0; /* if interrupted by a signal, treat it as if it's EINPROGRESS */
-
-		mio_seterrwithsyserr (mio, 0, errno);
-		return -1;
-	}
-
-accept_done:
 	/* use rdev->dev_size when instantiating a client sck device
-	 * instead of MIO_SIZEOF(mio_dev_sck_t). therefore, the 
+	 * instead of MIO_SIZEOF(mio_dev_sck_t). therefore, the  
 	 * extension area as big as that of the master sck device
 	 * is created in the client sck device */
 	clidev = (mio_dev_sck_t*)mio_dev_make(mio, rdev->dev_size, &dev_mth_clisck, rdev->dev_evcb, &clisck); 
@@ -1407,10 +1483,14 @@ accept_done:
 		return -1;
 	}
 
+// TODO:
+//if (clidev->type == MIO_DEV_SCK_QX) change it to the specified type..
+// TODO:
+
 	MIO_ASSERT (mio, clidev->hnd == clisck);
 
 	clidev->dev_cap |= MIO_DEV_CAP_IN | MIO_DEV_CAP_OUT | MIO_DEV_CAP_STREAM;
-	clidev->remoteaddr = remoteaddr;
+	clidev->remoteaddr = *remoteaddr;
 
 	addrlen = MIO_SIZEOF(clidev->localaddr);
 	if (getsockname(clisck, (struct sockaddr*)&clidev->localaddr, &addrlen) == -1) clidev->localaddr = rdev->localaddr;
@@ -1491,6 +1571,55 @@ accept_done:
 	return 0;
 }
 
+static int accept_incoming_connection (mio_dev_sck_t* rdev)
+{
+	mio_t* mio = rdev->mio;
+	mio_syshnd_t clisck;
+	mio_skad_t remoteaddr;
+	mio_scklen_t addrlen;
+	int flags;
+
+	/* this is a server(lisening) socket */
+
+#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC) && defined(HAVE_ACCEPT4)
+	flags = SOCK_NONBLOCK | SOCK_CLOEXEC;
+
+	addrlen = MIO_SIZEOF(remoteaddr);
+	clisck = accept4(rdev->hnd, (struct sockaddr*)&remoteaddr, &addrlen, flags);
+	if (clisck <= -1)
+	{
+		 if (errno != ENOSYS)
+		 {
+			if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;
+			if (errno == EINTR) return 0; /* if interrupted by a signal, treat it as if it's EINPROGRESS */
+
+			mio_seterrwithsyserr (mio, 0, errno);
+			return -1;
+		 }
+
+		 /* go on for the normal 3-parameter accept */
+	}
+	else
+	{
+		 goto accept_done;
+	}
+
+#endif
+	addrlen = MIO_SIZEOF(remoteaddr);
+	clisck = accept(rdev->hnd, (struct sockaddr*)&remoteaddr, &addrlen);
+	if (clisck <=  -1)
+	{
+		if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;
+		if (errno == EINTR) return 0; /* if interrupted by a signal, treat it as if it's EINPROGRESS */
+
+		mio_seterrwithsyserr (mio, 0, errno);
+		return -1;
+	}
+
+accept_done:
+	return make_accepted_client_connection (rdev, clisck, &remoteaddr);
+}
+
 static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 {
 	mio_t* mio = dev->mio;
@@ -1686,7 +1815,7 @@ static int dev_evcb_sck_ready_stateless (mio_dev_t* dev, int events)
 		mio_scklen_t len;
 
 		len = MIO_SIZEOF(errcode);
-		if (getsockopt (rdev->hnd, SOL_SOCKET, SO_ERROR, (char*)&errcode, &len) == -1)
+		if (getsockopt(rdev->hnd, SOL_SOCKET, SO_ERROR, (char*)&errcode, &len) == -1)
 		{
 			/* the error number is set to the socket error code.
 			 * errno resulting from getsockopt() doesn't reflect the actual
@@ -1733,6 +1862,8 @@ static int dev_evcb_sck_on_write_stateless (mio_dev_t* dev, mio_iolen_t wrlen, v
 	return rdev->on_write(rdev, wrlen, wrctx, dstaddr->ptr);
 }
 
+/* ========================================================================= */
+
 static mio_dev_evcb_t dev_sck_event_callbacks_stateful =
 {
 	dev_evcb_sck_ready_stateful,
@@ -1746,6 +1877,86 @@ static mio_dev_evcb_t dev_sck_event_callbacks_stateless =
 	dev_evcb_sck_on_read_stateless,
 	dev_evcb_sck_on_write_stateless
 };
+/* ========================================================================= */
+
+static int dev_evcb_sck_ready_qx (mio_dev_t* dev, int events)
+{
+	mio_t* mio = dev->mio;
+	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
+
+	if (events & MIO_DEV_EVENT_ERR)
+	{
+		int errcode;
+		mio_scklen_t len;
+
+		len = MIO_SIZEOF(errcode);
+		if (getsockopt(rdev->hnd, SOL_SOCKET, SO_ERROR, (char*)&errcode, &len) == -1)
+		{
+			/* the error number is set to the socket error code.
+			 * errno resulting from getsockopt() doesn't reflect the actual
+			 * socket error. so errno is not used to set the error number.
+			 * instead, the generic device error MIO_EDEVERRR is used */
+			mio_seterrbfmt (mio, MIO_EDEVERR, "device error - unable to get SO_ERROR");
+		}
+		else
+		{
+			mio_seterrwithsyserr (rdev->mio, 0, errcode);
+		}
+		return -1;
+	}
+	else if (events & MIO_DEV_EVENT_HUP)
+	{
+		mio_seterrnum (mio, MIO_EDEVHUP);
+		return -1;
+	}
+
+	return 1; /* the device is ok. carry on reading or writing */
+}
+
+
+static int dev_evcb_sck_on_read_qx (mio_dev_t* dev, const void* data, mio_iolen_t dlen, const mio_devaddr_t* srcaddr)
+{
+	mio_t* mio = dev->mio;
+	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
+	mio_dev_sck_qxmsg_t* qxmsg;
+
+	if (dlen != MIO_SIZEOF(*qxmsg))
+	{
+		mio_seterrbfmt (mio, MIO_EINVAL, "wrong qx packet size");
+		return -1;
+	}
+
+	qxmsg = (mio_dev_sck_qxmsg_t*)data;
+	if (qxmsg->cmd == MIO_DEV_SCK_QXMSG_NEWCONN)
+	{
+		if (make_accepted_client_connection(rdev, qxmsg->syshnd, &qxmsg->remoteaddr) <= -1) 
+		{
+			close (qxmsg->syshnd);
+			return -1;
+		}
+	}
+	else
+	{
+		mio_seterrbfmt (mio, MIO_EINVAL, "wrong qx command code");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int dev_evcb_sck_on_write_qx (mio_dev_t* dev, mio_iolen_t wrlen, void* wrctx, const mio_devaddr_t* dstaddr)
+{
+	/*mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;*/
+	/* this should not be called */
+	return 0;
+}
+
+static mio_dev_evcb_t dev_sck_event_callbacks_qx =
+{
+	dev_evcb_sck_ready_qx,
+	dev_evcb_sck_on_read_qx,
+	dev_evcb_sck_on_write_qx
+};
 
 /* ========================================================================= */
 
@@ -1759,7 +1970,13 @@ mio_dev_sck_t* mio_dev_sck_make (mio_t* mio, mio_oow_t xtnsize, const mio_dev_sc
 		return MIO_NULL;
 	}
 
-	if (sck_type_map[info->type].extra_dev_cap & MIO_DEV_CAP_STREAM) /* can't use the IS_STATEFUL() macro yet */
+	if (info->type == MIO_DEV_SCK_QX)
+	{
+		rdev = (mio_dev_sck_t*)mio_dev_make(
+			mio, MIO_SIZEOF(mio_dev_sck_t) + xtnsize,
+			&dev_sck_methods_stateless, &dev_sck_event_callbacks_qx, (void*)info);
+	}
+	else if (sck_type_map[info->type].extra_dev_cap & MIO_DEV_CAP_STREAM) /* can't use the IS_STATEFUL() macro yet */
 	{
 		rdev = (mio_dev_sck_t*)mio_dev_make(
 			mio, MIO_SIZEOF(mio_dev_sck_t) + xtnsize,
@@ -1858,6 +2075,18 @@ int mio_dev_sck_sendfileok (mio_dev_sck_t* dev)
 #endif
 }
 
+int mio_dev_sck_writetosidechan (mio_dev_sck_t* dev, const void* dptr, mio_oow_t dlen)
+{
+	if (dev->side_chan == MIO_SYSHND_INVALID)
+	{
+		mio_seterrnum (dev->mio, MIO_ENOCAPA);
+		return -1;
+	}
+
+	write (dev->side_chan, dptr, dlen);
+	return 0;
+}
+
 /* ========================================================================= */
 
 mio_uint16_t mio_checksum_ip (const void* hdr, mio_oow_t len)
diff --git a/mio/lib/sys-mux.c b/mio/lib/sys-mux.c
index 6f78744..0430272 100644
--- a/mio/lib/sys-mux.c
+++ b/mio/lib/sys-mux.c
@@ -41,13 +41,36 @@ int mio_sys_initmux (mio_t* mio)
 	mio_sys_mux_t* mux = &mio->sysdep->mux;
 
 #if defined(USE_EPOLL)
-	mux->hnd = epoll_create(1000); /* TODO: choose proper initial size? */
+
+#if defined(HAVE_EPOLL_CREATE1)
+	mux->hnd = epoll_create1(O_CLOEXEC);
+	if (mux->hnd == -1)
+	{
+		if (errno == ENOSYS) goto normal_epoll_create; /* kernel doesn't support it */
+		mio_seterrwithsyserr (mio, 0, errno);
+		return -1;
+	}
+	goto epoll_create_done;
+
+normal_epoll_create:
+#endif
+
+	mux->hnd = epoll_create(16384); /* TODO: choose proper initial size? */
 	if (mux->hnd == -1)
 	{
 		mio_seterrwithsyserr (mio, 0, errno);
 		return -1;
 	}
-#endif
+
+#if defined(FD_CLOEXEC)
+	{
+		int flags = fcntl(mux->hnd, F_GETFD, 0);
+		if (flags >= 0) fcntl(mux->hnd, F_SETFD, flags | FD_CLOEXEC);
+	}
+#endif /* FD_CLOEXEC */
+
+epoll_create_done:
+#endif /* USE_EPOLL */
 
 	return 0;
 }
@@ -254,7 +277,7 @@ int mio_sys_ctrlmux (mio_t* mio, mio_sys_mux_cmd_t cmd, mio_dev_t* dev, int dev_
 	}
 	if (dev_cap & MIO_DEV_CAP_OUT_WATCHED) events |= EPOLLOUT;
 
-	ev.events = events | EPOLLHUP | EPOLLERR /*| EPOLLET*/;
+	ev.events = events | EPOLLHUP | EPOLLERR /*| EPOLLET*/; /* TODO: ready to support edge-trigger? */
 	ev.data.ptr = dev;
 
 	switch (cmd)
diff --git a/mio/lib/sys-prv.h b/mio/lib/sys-prv.h
index 93f71e3..d9c2ca0 100644
--- a/mio/lib/sys-prv.h
+++ b/mio/lib/sys-prv.h
@@ -68,7 +68,7 @@ struct mio_sys_mux_t
 struct mio_sys_mux_t
 {
 	int hnd;
-	struct epoll_event revs[128]; /* TODO: is it a good size? */
+	struct epoll_event revs[1024]; /* TODO: is it a good size? */
 };
 
 #endif
diff --git a/mio/lib/sys.c b/mio/lib/sys.c
index 159758b..6dcb734 100644
--- a/mio/lib/sys.c
+++ b/mio/lib/sys.c
@@ -90,3 +90,22 @@ int mio_makesyshndasync (mio_t* mio, mio_syshnd_t hnd)
 	return -1;
 #endif
 }
+
+int mio_makesyshndcloexec (mio_t* mio, mio_syshnd_t hnd)
+{
+#if defined(F_GETFL) && defined(F_SETFL) && defined(FD_CLOEXEC)
+	int flags;
+
+	if ((flags = fcntl(hnd, F_GETFD)) <= -1 ||
+	    (flags = fcntl(hnd, F_SETFD, flags | FD_CLOEXEC)) <= -1)
+	{
+		mio_seterrwithsyserr (mio, 0, errno);
+		return -1;
+	}
+
+	return 0;
+#else
+	mio_seterrnum (mio, MIO_ENOIMPL);
+	return -1;
+#endif
+}