diff --git a/sbin/mount_nullfs/mount_nullfs.8 b/sbin/mount_nullfs/mount_nullfs.8
index 177ecdd..71d1835 100644
--- a/sbin/mount_nullfs/mount_nullfs.8
+++ b/sbin/mount_nullfs/mount_nullfs.8
@@ -79,7 +79,13 @@ Options are specified with a
 flag followed by a comma separated string of options.
 See the
 .Xr mount 8
-man page for possible options and their meanings.
+man page for standard options and their meanings.
+Options specific for
+.Nm :
+.Bl -tag -width sobypass
+.It Cm sobypass
+Bypass unix socket operations to the lower layer.
+.El
 .El
 .Pp
 The null layer has two purposes.
diff --git a/sbin/mount_nullfs/mount_nullfs.c b/sbin/mount_nullfs/mount_nullfs.c
index 4f84954..46ea1e6 100644
--- a/sbin/mount_nullfs/mount_nullfs.c
+++ b/sbin/mount_nullfs/mount_nullfs.c
@@ -48,6 +48,8 @@ static const char rcsid[] =
 #include <sys/mount.h>
 #include <sys/uio.h>
 
+#include <fs/nullfs/null.h>
+
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -59,25 +61,28 @@ static const char rcsid[] =
 
 static struct mntopt mopts[] = {
 	MOPT_STDOPTS,
+	{"sobypass", 0, NULLMNT_SOBYPASS, 1},
 	MOPT_END
 };
 
+static char fstype[] = "nullfs";
+
 int	subdir(const char *, const char *);
 static void	usage(void) __dead2;
 
 int
 main(int argc, char *argv[])
 {
-	struct iovec iov[6];
-	int ch, mntflags;
+	struct iovec *iov;
+	int ch, mntflags, nullflags, iovlen;
 	char source[MAXPATHLEN];
 	char target[MAXPATHLEN];
 
-	mntflags = 0;
+	mntflags = nullflags = 0;
 	while ((ch = getopt(argc, argv, "o:")) != -1)
 		switch(ch) {
 		case 'o':
-			getmntopts(optarg, mopts, &mntflags, 0);
+			getmntopts(optarg, mopts, &mntflags, &nullflags);
 			break;
 		case '?':
 		default:
@@ -97,20 +102,15 @@ main(int argc, char *argv[])
 		errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
 		    argv[0], target, argv[1]);
 
-	iov[0].iov_base = strdup("fstype");
-	iov[0].iov_len = sizeof("fstype");
-	iov[1].iov_base = strdup("nullfs");
-	iov[1].iov_len = strlen(iov[1].iov_base) + 1;
-	iov[2].iov_base = strdup("fspath");
-	iov[2].iov_len = sizeof("fspath");
-	iov[3].iov_base = source;
-	iov[3].iov_len = strlen(source) + 1;
-	iov[4].iov_base = strdup("target");
-	iov[4].iov_len = sizeof("target");
-	iov[5].iov_base = target;
-	iov[5].iov_len = strlen(target) + 1;
-
-	if (nmount(iov, 6, mntflags))
+	iov = NULL;
+	iovlen = 0;
+	build_iovec(&iov, &iovlen, "fstype", fstype, (size_t)-1);
+	build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1);
+	build_iovec(&iov, &iovlen, "target", target, (size_t)-1);
+	if ((nullflags & NULLMNT_SOBYPASS) != 0)
+		build_iovec(&iov, &iovlen, "sobypass", NULL, 0);
+
+	if (nmount(iov, iovlen, mntflags))
 		err(1, NULL);
 	exit(0);
 }
diff --git a/sys/fs/nullfs/null.h b/sys/fs/nullfs/null.h
index c8fc5de..81acbee 100644
--- a/sys/fs/nullfs/null.h
+++ b/sys/fs/nullfs/null.h
@@ -37,8 +37,15 @@
 struct null_mount {
 	struct mount	*nullm_vfs;
 	struct vnode	*nullm_rootvp;	/* Reference to root null_node */
+	int		nullm_flags;	/* nullfs options specific for mount */
 };
 
+/*
+ * Flags stored in nullm_flags.
+ */
+#define	NULLMNT_SOBYPASS	0x00000001	/* Bypass unix socket operations
+						   to lower node */
+
 #ifdef _KERNEL
 /*
  * A cache of vnode references
diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c
index 8c00f87..6d512fc 100644
--- a/sys/fs/nullfs/null_vfsops.c
+++ b/sys/fs/nullfs/null_vfsops.c
@@ -183,6 +183,11 @@ nullfs_mount(struct mount *mp)
 	MNT_ILOCK(mp);
 	mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE;
 	MNT_IUNLOCK(mp);
+
+	xmp->nullm_flags = 0;
+	if (vfs_getopt(mp->mnt_optnew, "sobypass", NULL, NULL) == 0)
+		xmp->nullm_flags |= NULLMNT_SOBYPASS;
+
 	mp->mnt_data =  xmp;
 	vfs_getnewfsid(mp);
 
diff --git a/sys/fs/nullfs/null_vnops.c b/sys/fs/nullfs/null_vnops.c
index bcf8750..ff1a2d0 100644
--- a/sys/fs/nullfs/null_vnops.c
+++ b/sys/fs/nullfs/null_vnops.c
@@ -816,6 +816,48 @@ null_vptocnp(struct vop_vptocnp_args *ap)
 	return (error);
 }
 
+static int
+null_unpbind(struct vop_unpbind_args *ap)
+{
+	struct vnode *vp;
+	struct null_mount *xmp;
+
+	vp = ap->a_vp;
+	xmp = vp->v_mount->mnt_data;
+	if (xmp->nullm_flags & NULLMNT_SOBYPASS)
+		return (null_bypass((struct vop_generic_args *)ap));
+	else
+		return (vop_stdunpbind(ap));
+}
+
+static int
+null_unpconnect(struct vop_unpconnect_args *ap)
+{
+	struct vnode *vp;
+	struct null_mount *xmp;
+
+	vp = ap->a_vp;
+	xmp = vp->v_mount->mnt_data;
+	if (xmp->nullm_flags & NULLMNT_SOBYPASS)
+		return (null_bypass((struct vop_generic_args *)ap));
+	else
+		return (vop_stdunpconnect(ap));
+}
+
+static int
+null_unpdetach(struct vop_unpdetach_args *ap)
+{
+	struct vnode *vp;
+	struct null_mount *xmp;
+
+	vp = ap->a_vp;
+	xmp = vp->v_mount->mnt_data;
+	if (xmp->nullm_flags & NULLMNT_SOBYPASS)
+		return (null_bypass((struct vop_generic_args *)ap));
+	else
+		return (vop_stdunpdetach(ap));
+}
+
 /*
  * Global vfs data structures
  */
@@ -841,4 +883,7 @@ struct vop_vector null_vnodeops = {
 	.vop_unlock =		null_unlock,
 	.vop_vptocnp =		null_vptocnp,
 	.vop_vptofh =		null_vptofh,
+	.vop_unpbind =		null_unpbind,
+	.vop_unpconnect =	null_unpconnect,
+	.vop_unpdetach =	null_unpdetach,
 };
diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index 3a439ec..c7c2881 100644
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -542,7 +542,7 @@ restart:
 
 	UNP_LINK_WLOCK();
 	UNP_PCB_LOCK(unp);
-	vp->v_socket = unp->unp_socket;
+	VOP_UNPBIND(vp, unp->unp_socket);
 	unp->unp_vnode = vp;
 	unp->unp_addr = soun;
 	unp->unp_flags &= ~UNP_BINDING;
@@ -638,7 +638,7 @@ uipc_detach(struct socket *so)
 	 * XXXRW: Should assert vp->v_socket == so.
 	 */
 	if ((vp = unp->unp_vnode) != NULL) {
-		unp->unp_vnode->v_socket = NULL;
+		VOP_UNPDETACH(vp);
 		unp->unp_vnode = NULL;
 	}
 	unp2 = unp->unp_conn;
@@ -1308,7 +1308,7 @@ unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
 	 * and to protect simultaneous locking of multiple pcbs.
 	 */
 	UNP_LINK_WLOCK();
-	so2 = vp->v_socket;
+	VOP_UNPCONNECT(vp, &so2);
 	if (so2 == NULL) {
 		error = ECONNREFUSED;
 		goto bad2;
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index e47498e..448e99b 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -123,6 +123,9 @@ struct vop_vector default_vnodeops = {
 	.vop_unlock =		vop_stdunlock,
 	.vop_vptocnp =		vop_stdvptocnp,
 	.vop_vptofh =		vop_stdvptofh,
+	.vop_unpbind =		vop_stdunpbind,
+	.vop_unpconnect =	vop_stdunpconnect,
+	.vop_unpdetach =	vop_stdunpdetach,
 };
 
 /*
@@ -1037,6 +1040,39 @@ vop_stdadvise(struct vop_advise_args *ap)
 	return (error);
 }
 
+int
+vop_stdunpbind(struct vop_unpbind_args *ap)
+{
+	struct vnode *vp;
+
+	vp = ap->a_vp;
+
+	vp->v_socket = ap->a_socket;
+	return (0);
+}
+
+int
+vop_stdunpconnect(struct vop_unpconnect_args *ap)
+{
+	struct vnode *vp;
+
+	vp = ap->a_vp;
+
+	*ap->a_socket = vp->v_socket;
+	return (0);
+}
+
+int
+vop_stdunpdetach(struct vop_unpdetach_args *ap)
+{
+	struct vnode *vp;
+
+	vp = ap->a_vp;
+
+	vp->v_socket = NULL;
+	return (0);
+}
+
 /*
  * vfs default ops
  * used to fill the vfs function table to get reasonable default return values.
diff --git a/sys/kern/vnode_if.src b/sys/kern/vnode_if.src
index 6f24d17..e17a034 100644
--- a/sys/kern/vnode_if.src
+++ b/sys/kern/vnode_if.src
@@ -637,3 +637,23 @@ vop_advise {
 	IN off_t end;
 	IN int advice;
 };
+
+%% unpbind	vp	E E E
+
+vop_unpbind {
+	IN struct vnode *vp;
+	IN struct socket *socket;
+};
+
+%% unpconnect	vp	E E E
+
+vop_unpconnect {
+	IN struct vnode *vp;
+	OUT struct socket **socket;
+};
+
+%% unpdetach	vp	E E E
+
+vop_unpdetach {
+	IN struct vnode *vp;
+};