diff --git a/src/include/sndio.h b/src/include/sndio.h
index dcb9ddfb..4fed3d5c 100644
--- a/src/include/sndio.h
+++ b/src/include/sndio.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sndio.h,v 1.9 2015/12/20 11:29:29 ratchov Exp $	*/
+/*	$OpenBSD: sndio.h,v 1.10 2020/02/26 13:53:58 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -25,11 +25,17 @@
 #define SIO_DEVANY	"default"
 #define MIO_PORTANY	"default"
 
+/*
+ * limits
+ */
+#define SIOCTL_NAMEMAX		12	/* max name length */
+
 /*
  * private ``handle'' structure
  */
 struct sio_hdl;
 struct mio_hdl;
+struct sioctl_hdl;
 
 /*
  * parameters of a full-duplex stream
@@ -84,6 +90,33 @@ struct sio_cap {
 
 #define SIO_XSTRINGS { "ignore", "sync", "error" }
 
+/*
+ * controlled component of the device
+ */
+struct sioctl_node {
+	char name[SIOCTL_NAMEMAX];	/* ex. "spkr" */
+	int unit;			/* optional number or -1 */
+};
+
+/*
+ * description of a control (index, value) pair
+ */
+struct sioctl_desc {
+	unsigned int addr;		/* control address */
+#define SIOCTL_NONE		0	/* deleted */
+#define SIOCTL_NUM		2	/* integer in the 0..127 range */
+#define SIOCTL_SW		3	/* on/off switch (0 or 1) */
+#define SIOCTL_VEC		4	/* number, element of vector */
+#define SIOCTL_LIST		5	/* switch, element of a list */
+	unsigned int type;		/* one of above */
+	char func[SIOCTL_NAMEMAX];	/* function name, ex. "level" */
+	char group[SIOCTL_NAMEMAX];	/* group this control belongs to */
+	struct sioctl_node node0;	/* affected node */
+	struct sioctl_node node1;	/* dito for SIOCTL_{VEC,LIST} */
+	unsigned int maxval;		/* max value for SIOCTL_{NUM,VEC} */
+	int __pad[3];
+};
+
 /*
  * mode bitmap
  */
@@ -91,6 +124,8 @@ struct sio_cap {
 #define SIO_REC		2
 #define MIO_OUT		4
 #define MIO_IN		8
+#define SIOCTL_READ	0x100
+#define SIOCTL_WRITE	0x200
 
 /*
  * default bytes per sample for the given bits per sample
@@ -144,10 +179,24 @@ int mio_pollfd(struct mio_hdl *, struct pollfd *, int);
 int mio_revents(struct mio_hdl *, struct pollfd *);
 int mio_eof(struct mio_hdl *);
 
+struct sioctl_hdl *sioctl_open(const char *, unsigned int, int);
+void sioctl_close(struct sioctl_hdl *);
+int sioctl_ondesc(struct sioctl_hdl *,
+    void (*)(void *, struct sioctl_desc *, int), void *);
+int sioctl_onval(struct sioctl_hdl *,
+    void (*)(void *, unsigned int, unsigned int), void *);
+int sioctl_setval(struct sioctl_hdl *, unsigned int, unsigned int);
+int sioctl_nfds(struct sioctl_hdl *);
+int sioctl_pollfd(struct sioctl_hdl *, struct pollfd *, int);
+int sioctl_revents(struct sioctl_hdl *, struct pollfd *);
+int sioctl_eof(struct sioctl_hdl *);
+
 int mio_rmidi_getfd(const char *, unsigned int, int);
 struct mio_hdl *mio_rmidi_fdopen(int, unsigned int, int);
 int sio_sun_getfd(const char *, unsigned int, int);
 struct sio_hdl *sio_sun_fdopen(int, unsigned int, int);
+int sioctl_sun_getfd(const char *, unsigned int, int);
+struct sioctl_hdl *sioctl_sun_fdopen(int, unsigned int, int);
 
 #ifdef __cplusplus
 }