diff --git a/src/psp-un.h b/src/psp-un.h
new file mode 100644
index 0000000..41bde17
--- /dev/null
+++ b/src/psp-un.h
@@ -0,0 +1,82 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _SYS_UN_H_
+#define _SYS_UN_H_
+
+#include <sys/cdefs.h>
+#include <sys/_types.h>
+
+#ifndef _SA_FAMILY_T_DECLARED
+typedef	__sa_family_t	sa_family_t;
+#define	_SA_FAMILY_T_DECLARED
+#endif
+
+/*
+ * Historically, (struct sockaddr) needed to fit inside an mbuf.
+ * For this reason, UNIX domain sockets were therefore limited to
+ * 104 bytes. While this limit is no longer necessary, it is kept for
+ * binary compatibility reasons.
+ */
+#define	SUNPATHLEN	104
+
+/*
+ * Definitions for UNIX IPC domain.
+ */
+struct sockaddr_un {
+	unsigned char	sun_len;	/* sockaddr len including null */
+	sa_family_t	sun_family;	/* AF_UNIX */
+	char	sun_path[SUNPATHLEN];	/* path name (gag) */
+};
+
+#if __BSD_VISIBLE
+
+#define	SOL_LOCAL		0	/* Options for local socket */
+
+/* Socket options. */
+#define	LOCAL_PEERCRED		1	/* retrieve peer credentials */
+#define	LOCAL_CREDS		2	/* pass credentials to receiver */
+#define	LOCAL_CREDS_PERSISTENT	3	/* pass credentials to receiver */
+
+/* Start of reserved space for third-party socket options. */
+#define	LOCAL_VENDOR		SO_VENDOR
+
+#ifndef _KERNEL
+
+/* actual length of an initialized sockaddr_un */
+#define SUN_LEN(su) \
+	(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
+
+#endif /* !_KERNEL */
+
+#endif /* __BSD_VISIBLE */
+
+#endif /* !_SYS_UN_H_ */