/*
 * Copyright (c) 1999-2017 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 * Kernel Control domain - allows control connections to
 *  and to read/write data.
 *
 * Vincent Lubet, 040506
 * Christophe Allie, 010928
 * Justin C. Walker, 990319
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/syslog.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/sys_domain.h>
#include <sys/kern_event.h>
#include <sys/kern_control.h>
#include <sys/kauth.h>
#include <sys/sysctl.h>
#include <sys/proc_info.h>
#include <net/if_var.h>

#include <mach/vm_types.h>

#include <kern/thread.h>

struct kctl {
	TAILQ_ENTRY(kctl)	next;		/* controller chain */
	kern_ctl_ref		kctlref;

	/* controller information provided when registering */
	char			name[MAX_KCTL_NAME];	/* unique identifier */
	u_int32_t		id;
	u_int32_t		reg_unit;

	/* misc communication information */
	u_int32_t		flags;		/* support flags */
	u_int32_t		recvbufsize;	/* request more than the default buffer size */
	u_int32_t		sendbufsize;	/* request more than the default buffer size */

	/* Dispatch functions */
	ctl_bind_func		bind;		/* Prepare contact */
	ctl_connect_func	connect;	/* Make contact */
	ctl_disconnect_func	disconnect;	/* Break contact */
	ctl_send_func		send;		/* Send data to nke */
	ctl_send_list_func	send_list;	/* Send list of packets */
	ctl_setopt_func		setopt;		/* set kctl configuration */
	ctl_getopt_func		getopt;		/* get kctl configuration */
	ctl_rcvd_func		rcvd;		/* Notify nke when client reads data */

	TAILQ_HEAD(, ctl_cb)	kcb_head;
	u_int32_t		lastunit;
};

struct ctl_cb {
	TAILQ_ENTRY(ctl_cb)	next;		/* controller chain */
	lck_mtx_t		*mtx;
	struct socket		*so;		/* controlling socket */
	struct kctl		*kctl;		/* back pointer to controller */
	void			*userdata;
	struct sockaddr_ctl 	sac;
	u_int32_t		usecount;
};

#ifndef ROUNDUP64
#define	ROUNDUP64(x) P2ROUNDUP((x), sizeof (u_int64_t))
#endif

#ifndef ADVANCE64
#define	ADVANCE64(p, n) (void*)((char *)(p) + ROUNDUP64(n))
#endif

/*
 * Definitions and vars for we support
 */

#define	CTL_SENDSIZE	(2 * 1024)	/* default buffer size */
#define	CTL_RECVSIZE 	(8 * 1024)	/* default buffer size */

/*
 * Definitions and vars for we support
 */

static u_int32_t	ctl_maxunit = 65536;
static lck_grp_attr_t	*ctl_lck_grp_attr = 0;
static lck_attr_t	*ctl_lck_attr = 0;
static lck_grp_t	*ctl_lck_grp = 0;
static lck_mtx_t 	*ctl_mtx;

/* all the controllers are chained */
TAILQ_HEAD(kctl_list, kctl) 	ctl_head;

static int ctl_attach(struct socket *, int, struct proc *);
static int ctl_detach(struct socket *);
static int ctl_sofreelastref(struct socket *so);
static int ctl_bind(struct socket *, struct sockaddr *, struct proc *);
static int ctl_connect(struct socket *, struct sockaddr *, struct proc *);
static int ctl_disconnect(struct socket *);
static int ctl_ioctl(struct socket *so, u_long cmd, caddr_t data,
			struct ifnet *ifp, struct proc *p);
static int ctl_send(struct socket *, int, struct mbuf *,
	    struct sockaddr *, struct mbuf *, struct proc *);
static int ctl_send_list(struct socket *, int, struct mbuf *,
	    struct sockaddr *, struct mbuf *, struct proc *);
static int ctl_ctloutput(struct socket *, struct sockopt *);
static int ctl_peeraddr(struct socket *so, struct sockaddr **nam);
static int ctl_usr_rcvd(struct socket *so, int flags);

static struct kctl *ctl_find_by_name(const char *);
static struct kctl *ctl_find_by_id_unit(u_int32_t id, u_int32_t unit);

static struct socket *kcb_find_socket(kern_ctl_ref kctlref, u_int32_t unit,
	u_int32_t *);
static struct ctl_cb *kcb_find(struct kctl *, u_int32_t unit);
static void ctl_post_msg(u_int32_t event_code, u_int32_t id);

static int ctl_lock(struct socket *, int, void *);
static int ctl_unlock(struct socket *, int, void *);
static lck_mtx_t * ctl_getlock(struct socket *, int);

static struct pr_usrreqs ctl_usrreqs = {
	.pru_attach =		ctl_attach,
	.pru_bind =		ctl_bind,
	.pru_connect =		ctl_connect,
	.pru_control =		ctl_ioctl,
	.pru_detach =		ctl_detach,
	.pru_disconnect =	ctl_disconnect,
	.pru_peeraddr =		ctl_peeraddr,
	.pru_rcvd =		ctl_usr_rcvd,
	.pru_send =		ctl_send,
	.pru_send_list =	ctl_send_list,
	.pru_sosend =		sosend,
	.pru_sosend_list =	sosend_list,
	.pru_soreceive =	soreceive,
	.pru_soreceive_list =	soreceive_list,
};

static struct protosw kctlsw[] = {
{
	.pr_type =	SOCK_DGRAM,
	.pr_protocol =	SYSPROTO_CONTROL,
	.pr_flags =	PR_ATOMIC|PR_CONNREQUIRED|PR_PCBLOCK|PR_WANTRCVD,
	.pr_ctloutput =	ctl_ctloutput,
	.pr_usrreqs =	&ctl_usrreqs,
	.pr_lock =	ctl_lock,
	.pr_unlock =	ctl_unlock,
	.pr_getlock =	ctl_getlock,
},
{
	.pr_type =	SOCK_STREAM,
	.pr_protocol =	SYSPROTO_CONTROL,
	.pr_flags =	PR_CONNREQUIRED|PR_PCBLOCK|PR_WANTRCVD,
	.pr_ctloutput =	ctl_ctloutput,
	.pr_usrreqs =	&ctl_usrreqs,
	.pr_lock =	ctl_lock,
	.pr_unlock =	ctl_unlock,
	.pr_getlock =	ctl_getlock,
}
};

__private_extern__ int kctl_reg_list SYSCTL_HANDLER_ARGS;
__private_extern__ int kctl_pcblist SYSCTL_HANDLER_ARGS;
__private_extern__ int kctl_getstat SYSCTL_HANDLER_ARGS;


SYSCTL_NODE(_net_systm, OID_AUTO, kctl,
	CTLFLAG_RW|CTLFLAG_LOCKED, 0, "Kernel control family");

struct kctlstat kctlstat;
SYSCTL_PROC(_net_systm_kctl, OID_AUTO, stats,
    CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
    kctl_getstat, "S,kctlstat", "");

SYSCTL_PROC(_net_systm_kctl, OID_AUTO, reg_list,
	CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
	kctl_reg_list, "S,xkctl_reg", "");

SYSCTL_PROC(_net_systm_kctl, OID_AUTO, pcblist,
	CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
	kctl_pcblist, "S,xkctlpcb", "");

u_int32_t ctl_autorcvbuf_max = 256 * 1024;
SYSCTL_INT(_net_systm_kctl, OID_AUTO, autorcvbufmax,
	CTLFLAG_RW | CTLFLAG_LOCKED, &ctl_autorcvbuf_max, 0, "");

u_int32_t ctl_autorcvbuf_high = 0;
SYSCTL_INT(_net_systm_kctl, OID_AUTO, autorcvbufhigh,
	CTLFLAG_RD | CTLFLAG_LOCKED, &ctl_autorcvbuf_high, 0, "");

u_int32_t ctl_debug = 0;
SYSCTL_INT(_net_systm_kctl, OID_AUTO, debug,
	CTLFLAG_RW | CTLFLAG_LOCKED, &ctl_debug, 0, "");

#define	KCTL_TBL_INC 16

static uintptr_t kctl_tbl_size = 0;
static u_int32_t kctl_tbl_growing = 0;
static u_int32_t kctl_tbl_growing_waiting = 0;
static uintptr_t kctl_tbl_count = 0;
static struct kctl **kctl_table = NULL;
static uintptr_t kctl_ref_gencnt = 0;

static void kctl_tbl_grow(void);
static kern_ctl_ref kctl_make_ref(struct kctl *kctl);
static void kctl_delete_ref(kern_ctl_ref);
static struct kctl *kctl_from_ref(kern_ctl_ref);

/*
 * Install the protosw's for the Kernel Control manager.
 */
__private_extern__ void
kern_control_init(struct domain *dp)
{
	struct protosw *pr;
	int i;
	int kctl_proto_count = (sizeof (kctlsw) / sizeof (struct protosw));

	VERIFY(!(dp->dom_flags & DOM_INITIALIZED));
	VERIFY(dp == systemdomain);

	ctl_lck_grp_attr = lck_grp_attr_alloc_init();
	if (ctl_lck_grp_attr == NULL) {
		panic("%s: lck_grp_attr_alloc_init failed\n", __func__);
		/* NOTREACHED */
	}

	ctl_lck_grp = lck_grp_alloc_init("Kernel Control Protocol",
	    ctl_lck_grp_attr);
	if (ctl_lck_grp == NULL) {
		panic("%s: lck_grp_alloc_init failed\n", __func__);
		/* NOTREACHED */
	}

	ctl_lck_attr = lck_attr_alloc_init();
	if (ctl_lck_attr == NULL) {
		panic("%s: lck_attr_alloc_init failed\n", __func__);
		/* NOTREACHED */
	}

	ctl_mtx = lck_mtx_alloc_init(ctl_lck_grp, ctl_lck_attr);
	if (ctl_mtx == NULL) {
		panic("%s: lck_mtx_alloc_init failed\n", __func__);
		/* NOTREACHED */
	}
	TAILQ_INIT(&ctl_head);

	for (i = 0, pr = &kctlsw[0]; i < kctl_proto_count; i++, pr++)
		net_add_proto(pr, dp, 1);
}

static void
kcb_delete(struct ctl_cb *kcb)
{
	if (kcb != 0) {
		if (kcb->mtx != 0)
			lck_mtx_free(kcb->mtx, ctl_lck_grp);
		FREE(kcb, M_TEMP);
	}
}

/*
 * Kernel Controller user-request functions
 * attach function must exist and succeed
 * detach not necessary
 * we need a pcb for the per socket mutex
 */
static int
ctl_attach(struct socket *so, int proto, struct proc *p)
{
#pragma unused(proto, p)
	int error = 0;
	struct ctl_cb			*kcb = 0;

	MALLOC(kcb, struct ctl_cb *, sizeof(struct ctl_cb), M_TEMP, M_WAITOK);
	if (kcb == NULL) {
		error = ENOMEM;
		goto quit;
	}
	bzero(kcb, sizeof(struct ctl_cb));

	kcb->mtx = lck_mtx_alloc_init(ctl_lck_grp, ctl_lck_attr);
	if (kcb->mtx == NULL) {
		error = ENOMEM;
		goto quit;
	}
	kcb->so = so;
	so->so_pcb = (caddr_t)kcb;

quit:
	if (error != 0) {
		kcb_delete(kcb);
		kcb = 0;
	}
	return (error);
}

static int
ctl_sofreelastref(struct socket *so)
{
	struct ctl_cb 	*kcb = (struct ctl_cb *)so->so_pcb;

	so->so_pcb = 0;

	if (kcb != 0) {
		struct kctl		*kctl;
		if ((kctl = kcb->kctl) != 0) {
			lck_mtx_lock(ctl_mtx);
			TAILQ_REMOVE(&kctl->kcb_head, kcb, next);
			kctlstat.kcs_pcbcount--;
			kctlstat.kcs_gencnt++;
			lck_mtx_unlock(ctl_mtx);
		}
		kcb_delete(kcb);
	}
	sofreelastref(so, 1);
	return (0);
}

static int
ctl_detach(struct socket *so)
{
	struct ctl_cb 	*kcb = (struct ctl_cb *)so->so_pcb;

	if (kcb == 0)
		return (0);

	if (kcb->kctl != NULL && kcb->kctl->bind != NULL &&
	    kcb->userdata != NULL && !(so->so_state & SS_ISCONNECTED)) {
		// The unit was bound, but not connected
		// Invoke the disconnected call to cleanup
		if (kcb->kctl->disconnect != NULL) {
			socket_unlock(so, 0);
			(*kcb->kctl->disconnect)(kcb->kctl->kctlref,
			    kcb->sac.sc_unit, kcb->userdata);
			socket_lock(so, 0);
		}
	}

	soisdisconnected(so);
	so->so_flags |= SOF_PCBCLEARING;
	return (0);
}

static int
ctl_setup_kctl(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	struct kctl *kctl = NULL;
	int error = 0;
	struct sockaddr_ctl	sa;
	struct ctl_cb *kcb = (struct ctl_cb *)so->so_pcb;
	struct ctl_cb *kcb_next = NULL;
	u_quad_t sbmaxsize;
	u_int32_t recvbufsize, sendbufsize;

	if (kcb == 0) {
		panic("ctl_setup_kctl so_pcb null\n");
	}

	if (kcb->kctl != NULL) {
		// Already set up, skip
		return (0);
	}

	if (nam->sa_len != sizeof(struct sockaddr_ctl)) {
		return (EINVAL);
	}

	bcopy(nam, &sa, sizeof(struct sockaddr_ctl));

	lck_mtx_lock(ctl_mtx);
	kctl = ctl_find_by_id_unit(sa.sc_id, sa.sc_unit);
	if (kctl == NULL) {
		lck_mtx_unlock(ctl_mtx);
		return (ENOENT);
	}

	if (((kctl->flags & CTL_FLAG_REG_SOCK_STREAM) &&
		 (so->so_type != SOCK_STREAM)) ||
		(!(kctl->flags & CTL_FLAG_REG_SOCK_STREAM) &&
		 (so->so_type != SOCK_DGRAM))) {
			lck_mtx_unlock(ctl_mtx);
			return (EPROTOTYPE);
		}

	if (kctl->flags & CTL_FLAG_PRIVILEGED) {
		if (p == 0) {
			lck_mtx_unlock(ctl_mtx);
			return (EINVAL);
		}
		if (kauth_cred_issuser(kauth_cred_get()) == 0) {
			lck_mtx_unlock(ctl_mtx);
			return (EPERM);
		}
	}

	if ((kctl->flags & CTL_FLAG_REG_ID_UNIT) || sa.sc_unit != 0) {
		if (kcb_find(kctl, sa.sc_unit) != NULL) {
			lck_mtx_unlock(ctl_mtx);
			return (EBUSY);
		}
	} else {
		/* Find an unused ID, assumes control IDs are in order */
		u_int32_t unit = 1;

		TAILQ_FOREACH(kcb_next, &kctl->kcb_head, next) {
			if (kcb_next->sac.sc_unit > unit) {
				/* Found a gap, lets fill it in */
				break;
			}
			unit = kcb_next->sac.sc_unit + 1;
			if (unit == ctl_maxunit) {
				break;
			}
		}

		if (unit == ctl_maxunit) {
			lck_mtx_unlock(ctl_mtx);
			return (EBUSY);
		}

		sa.sc_unit = unit;
	}

	bcopy(&sa, &kcb->sac, sizeof(struct sockaddr_ctl));
	kcb->kctl = kctl;
	if (kcb_next != NULL) {
		TAILQ_INSERT_BEFORE(kcb_next, kcb, next);
	} else {
		TAILQ_INSERT_TAIL(&kctl->kcb_head, kcb, next);
	}
	kctlstat.kcs_pcbcount++;
	kctlstat.kcs_gencnt++;
	kctlstat.kcs_connections++;
	lck_mtx_unlock(ctl_mtx);

	/*
	 * rdar://15526688: Limit the send and receive sizes to sb_max
	 * by using the same scaling as sbreserve()
	 */
	sbmaxsize = (u_quad_t)sb_max * MCLBYTES / (MSIZE + MCLBYTES);

	if (kctl->sendbufsize > sbmaxsize) {
		sendbufsize = sbmaxsize;
	} else {
		sendbufsize = kctl->sendbufsize;
	}

	if (kctl->recvbufsize > sbmaxsize) {
		recvbufsize = sbmaxsize;
	} else {
		recvbufsize = kctl->recvbufsize;
	}

	error = soreserve(so, sendbufsize, recvbufsize);
	if (error) {
		if (ctl_debug)
			printf("%s - soreserve(%llx, %u, %u) error %d\n",
				   __func__, (uint64_t)VM_KERNEL_ADDRPERM(so),
				   sendbufsize, recvbufsize, error);
		goto done;
	}

done:
	if (error) {
		soisdisconnected(so);
		lck_mtx_lock(ctl_mtx);
		TAILQ_REMOVE(&kctl->kcb_head, kcb, next);
		kcb->kctl = NULL;
		kcb->sac.sc_unit = 0;
		kctlstat.kcs_pcbcount--;
		kctlstat.kcs_gencnt++;
		kctlstat.kcs_conn_fail++;
		lck_mtx_unlock(ctl_mtx);
	}
	return (error);
}

static int
ctl_bind(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	int error = 0;
	struct ctl_cb *kcb = (struct ctl_cb *)so->so_pcb;

	if (kcb == NULL) {
		panic("ctl_bind so_pcb null\n");
	}

	error = ctl_setup_kctl(so, nam, p);
	if (error) {
		return (error);
	}

	if (kcb->kctl == NULL) {
		panic("ctl_bind kctl null\n");
	}

	if (kcb->kctl->bind == NULL) {
		return (EINVAL);
	}

	socket_unlock(so, 0);
	error = (*kcb->kctl->bind)(kcb->kctl->kctlref, &kcb->sac, &kcb->userdata);
	socket_lock(so, 0);

	return (error);
}

static int
ctl_connect(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	int error = 0;
	struct ctl_cb *kcb = (struct ctl_cb *)so->so_pcb;

	if (kcb == NULL) {
		panic("ctl_connect so_pcb null\n");
	}

	error = ctl_setup_kctl(so, nam, p);
	if (error) {
		return (error);
	}

	if (kcb->kctl == NULL) {
		panic("ctl_connect kctl null\n");
	}

	soisconnecting(so);
	socket_unlock(so, 0);
	error = (*kcb->kctl->connect)(kcb->kctl->kctlref, &kcb->sac, &kcb->userdata);
	socket_lock(so, 0);
	if (error) {
		goto end;
	}
	soisconnected(so);

end:
	if (error && kcb->kctl->disconnect) {
		/*
		 * XXX Make sure we Don't check the return value
		 * of disconnect here.
		 * ipsec/utun_ctl_disconnect will return error when
		 * disconnect gets called after connect failure.
		 * However if we decide to check for disconnect return
		 * value here. Please make sure to revisit
		 * ipsec/utun_ctl_disconnect.
		 */
		socket_unlock(so, 0);
		(*kcb->kctl->disconnect)(kcb->kctl->kctlref, kcb->sac.sc_unit, kcb->userdata);
		socket_lock(so, 0);
	}
	if (error) {
		soisdisconnected(so);
		lck_mtx_lock(ctl_mtx);
		TAILQ_REMOVE(&kcb->kctl->kcb_head, kcb, next);
		kcb->kctl = NULL;
		kcb->sac.sc_unit = 0;
		kctlstat.kcs_pcbcount--;
		kctlstat.kcs_gencnt++;
		kctlstat.kcs_conn_fail++;
		lck_mtx_unlock(ctl_mtx);
	}
	return (error);
}

static int
ctl_disconnect(struct socket *so)
{
	struct ctl_cb 	*kcb = (struct ctl_cb *)so->so_pcb;

	if ((kcb = (struct ctl_cb *)so->so_pcb)) {
		struct kctl		*kctl = kcb->kctl;

		if (kctl && kctl->disconnect) {
			socket_unlock(so, 0);
			(*kctl->disconnect)(kctl->kctlref, kcb->sac.sc_unit,
			    kcb->userdata);
			socket_lock(so, 0);
		}

		soisdisconnected(so);

		socket_unlock(so, 0);
		lck_mtx_lock(ctl_mtx);
		kcb->kctl = 0;
		kcb->sac.sc_unit = 0;
		while (kcb->usecount != 0) {
			msleep(&kcb->usecount, ctl_mtx, 0, "kcb->usecount", 0);
		}
		TAILQ_REMOVE(&kctl->kcb_head, kcb, next);
		kctlstat.kcs_pcbcount--;
		kctlstat.kcs_gencnt++;
		lck_mtx_unlock(ctl_mtx);
		socket_lock(so, 0);
	}
	return (0);
}

static int
ctl_peeraddr(struct socket *so, struct sockaddr **nam)
{
	struct ctl_cb 		*kcb = (struct ctl_cb *)so->so_pcb;
	struct kctl			*kctl;
	struct sockaddr_ctl	sc;

	if (kcb == NULL)	/* sanity check */
		return (ENOTCONN);

	if ((kctl = kcb->kctl) == NULL)
		return (EINVAL);

	bzero(&sc, sizeof(struct sockaddr_ctl));
	sc.sc_len = sizeof(struct sockaddr_ctl);
	sc.sc_family = AF_SYSTEM;
	sc.ss_sysaddr = AF_SYS_CONTROL;
	sc.sc_id =  kctl->id;
	sc.sc_unit = kcb->sac.sc_unit;

	*nam = dup_sockaddr((struct sockaddr *)&sc, 1);

	return (0);
}

static void
ctl_sbrcv_trim(struct socket *so)
{
	struct sockbuf *sb = &so->so_rcv;

	if (sb->sb_hiwat > sb->sb_idealsize) {
		u_int32_t diff;
		int32_t trim;

		/*
		 * The difference between the ideal size and the
		 * current size is the upper bound of the trimage
		 */
		diff = sb->sb_hiwat - sb->sb_idealsize;
		/*
		 * We cannot trim below the outstanding data
		 */
		trim = sb->sb_hiwat - sb->sb_cc;

		trim = imin(trim, (int32_t)diff);

		if (trim > 0) {
			sbreserve(sb, (sb->sb_hiwat - trim));

			if (ctl_debug)
				printf("%s - shrunk to %d\n",
				    __func__, sb->sb_hiwat);
		}
	}
}

static int
ctl_usr_rcvd(struct socket *so, int flags)
{
	struct ctl_cb		*kcb = (struct ctl_cb *)so->so_pcb;
	struct kctl			*kctl;

	if ((kctl = kcb->kctl) == NULL) {
		return (EINVAL);
	}

	if (kctl->rcvd) {
		socket_unlock(so, 0);
		(*kctl->rcvd)(kctl->kctlref, kcb->sac.sc_unit, kcb->userdata, flags);
		socket_lock(so, 0);
	}

	ctl_sbrcv_trim(so);

	return (0);
}

static int
ctl_send(struct socket *so, int flags, struct mbuf *m,
	struct sockaddr *addr, struct mbuf *control,
	struct proc *p)
{
#pragma unused(addr, p)
	int		error = 0;
	struct ctl_cb 	*kcb = (struct ctl_cb *)so->so_pcb;
	struct kctl	*kctl;

	if (control)
		m_freem(control);

	if (kcb == NULL)	/* sanity check */
		error = ENOTCONN;

	if (error == 0 && (kctl = kcb->kctl) == NULL)
		error = EINVAL;

	if (error == 0 && kctl->send) {
		so_tc_update_stats(m, so, m_get_service_class(m));
		socket_unlock(so, 0);
		error = (*kctl->send)(kctl->kctlref, kcb->sac.sc_unit, kcb->userdata,
		    m, flags);
		socket_lock(so, 0);
	} else {
		m_freem(m);
		if (error == 0)
			error = ENOTSUP;
	}
	if (error != 0)
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_send_fail);
	return (error);
}

static int
ctl_send_list(struct socket *so, int flags, struct mbuf *m,
	    __unused struct sockaddr *addr, struct mbuf *control,
	    __unused struct proc *p)
{
	int		error = 0;
	struct ctl_cb 	*kcb = (struct ctl_cb *)so->so_pcb;
	struct kctl	*kctl;

	if (control)
		m_freem_list(control);

	if (kcb == NULL)	/* sanity check */
		error = ENOTCONN;

	if (error == 0 && (kctl = kcb->kctl) == NULL)
		error = EINVAL;

	if (error == 0 && kctl->send_list) {
		struct mbuf *nxt;

		for (nxt = m; nxt != NULL; nxt = nxt->m_nextpkt)
			so_tc_update_stats(nxt, so, m_get_service_class(nxt));

		socket_unlock(so, 0);
		error = (*kctl->send_list)(kctl->kctlref, kcb->sac.sc_unit,
		    kcb->userdata, m, flags);
		socket_lock(so, 0);
	} else if (error == 0 && kctl->send) {
		while (m != NULL && error == 0) {
			struct mbuf *nextpkt = m->m_nextpkt;

			m->m_nextpkt = NULL;
			so_tc_update_stats(m, so, m_get_service_class(m));
			socket_unlock(so, 0);
			error = (*kctl->send)(kctl->kctlref, kcb->sac.sc_unit,
			    kcb->userdata, m, flags);
			socket_lock(so, 0);
			m = nextpkt;
		}
		if (m != NULL)
			m_freem_list(m);
	} else {
		m_freem_list(m);
		if (error == 0)
			error = ENOTSUP;
	}
	if (error != 0)
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_send_list_fail);
	return (error);
}

static errno_t
ctl_rcvbspace(struct socket *so, u_int32_t datasize,
	u_int32_t kctlflags, u_int32_t flags)
{
	struct sockbuf *sb = &so->so_rcv;
	u_int32_t space = sbspace(sb);
	errno_t error;

	if ((kctlflags & CTL_FLAG_REG_CRIT) == 0) {
		if ((u_int32_t) space >= datasize)
			error = 0;
		else
			error = ENOBUFS;
	} else if ((flags & CTL_DATA_CRIT) == 0) {
		/*
		 * Reserve 25% for critical messages
		 */
		if (space < (sb->sb_hiwat >> 2) ||
		    space  < datasize)
			error = ENOBUFS;
		else
			error = 0;
	} else {
		u_int32_t autorcvbuf_max;

		/*
		 * Allow overcommit of 25%
		 */
		autorcvbuf_max = min(sb->sb_idealsize + (sb->sb_idealsize >> 2),
			ctl_autorcvbuf_max);

		if ((u_int32_t) space >= datasize) {
			error = 0;
		} else if (tcp_cansbgrow(sb) &&
		    sb->sb_hiwat < autorcvbuf_max) {
			/*
			 * Grow with a little bit of leeway
			 */
			u_int32_t grow = datasize - space + MSIZE;

			if (sbreserve(sb,
			    min((sb->sb_hiwat + grow), autorcvbuf_max)) == 1) {

				if (sb->sb_hiwat > ctl_autorcvbuf_high)
					ctl_autorcvbuf_high = sb->sb_hiwat;

				/*
				 * A final check
				 */
				if ((u_int32_t) sbspace(sb) >= datasize) {
					error = 0;
				} else {
					error = ENOBUFS;
				}

				if (ctl_debug)
					printf("%s - grown to %d error %d\n",
					    __func__, sb->sb_hiwat, error);
			} else {
				error = ENOBUFS;
			}
		} else {
			error = ENOBUFS;
		}
	}
	return (error);
}

errno_t
ctl_enqueuembuf(kern_ctl_ref kctlref, u_int32_t unit, struct mbuf *m,
    u_int32_t flags)
{
	struct socket 	*so;
	errno_t 	error = 0;
	int		len = m->m_pkthdr.len;
	u_int32_t	kctlflags;

	so = kcb_find_socket(kctlref, unit, &kctlflags);
	if (so == NULL) {
		return (EINVAL);
	}

	if (ctl_rcvbspace(so, len, kctlflags, flags) != 0) {
		error = ENOBUFS;
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fullsock);
		goto bye;
	}
	if ((flags & CTL_DATA_EOR))
		m->m_flags |= M_EOR;

	so_recv_data_stat(so, m, 0);
	if (sbappend(&so->so_rcv, m) != 0) {
		if ((flags & CTL_DATA_NOWAKEUP) == 0)
			sorwakeup(so);
	} else {
		error = ENOBUFS;
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fullsock);
	}
bye:
	if (ctl_debug && error != 0 && (flags & CTL_DATA_CRIT))
		printf("%s - crit data err %d len %d hiwat %d cc: %d\n",
			__func__, error, len,
			so->so_rcv.sb_hiwat, so->so_rcv.sb_cc);

	socket_unlock(so, 1);
	if (error != 0)
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fail);

	return (error);
}

/*
 * Compute space occupied by mbuf like sbappendrecord
 */
static int
m_space(struct mbuf *m)
{
	int space = 0;
	struct mbuf *nxt;

	for (nxt = m; nxt != NULL; nxt = nxt->m_next)
		space += nxt->m_len;

	return (space);
}

errno_t
ctl_enqueuembuf_list(void *kctlref, u_int32_t unit, struct mbuf *m_list,
	u_int32_t flags, struct mbuf **m_remain)
{
	struct socket *so = NULL;
	errno_t error = 0;
	struct mbuf *m, *nextpkt;
	int needwakeup = 0;
	int len = 0;
	u_int32_t kctlflags;

	/*
	 * Need to point the beginning of the list in case of early exit
	 */
	m = m_list;

	/*
	 * kcb_find_socket takes the socket lock with a reference
	 */
	so = kcb_find_socket(kctlref, unit, &kctlflags);
	if (so == NULL) {
		error = EINVAL;
		goto done;
	}

	if (kctlflags & CTL_FLAG_REG_SOCK_STREAM) {
		error = EOPNOTSUPP;
		goto done;
	}
	if (flags & CTL_DATA_EOR) {
		error = EINVAL;
		goto done;
	}

	for (m = m_list; m != NULL; m = nextpkt) {
		nextpkt = m->m_nextpkt;

		if (m->m_pkthdr.len == 0 && ctl_debug)
			printf("%s: %llx m_pkthdr.len is 0",
				__func__, (uint64_t)VM_KERNEL_ADDRPERM(m));

		/*
		 * The mbuf is either appended or freed by sbappendrecord()
		 * so it's not reliable from a data standpoint
		 */
		len = m_space(m);
		if (ctl_rcvbspace(so, len, kctlflags, flags) != 0) {
			error = ENOBUFS;
			OSIncrementAtomic64(
			    (SInt64 *)&kctlstat.kcs_enqueue_fullsock);
			break;
		} else {
			/*
			 * Unlink from the list, m is on its own
			 */
			m->m_nextpkt = NULL;
			so_recv_data_stat(so, m, 0);
			if (sbappendrecord(&so->so_rcv, m) != 0) {
				needwakeup = 1;
			} else {
				/*
				 * We free or return the remaining
				 * mbufs in the list
				 */
				m = nextpkt;
				error = ENOBUFS;
				OSIncrementAtomic64(
				    (SInt64 *)&kctlstat.kcs_enqueue_fullsock);
				break;
			}
		}
	}
	if (needwakeup && (flags & CTL_DATA_NOWAKEUP) == 0)
		sorwakeup(so);

done:
	if (so != NULL) {
		if (ctl_debug && error != 0 && (flags & CTL_DATA_CRIT))
			printf("%s - crit data err %d len %d hiwat %d cc: %d\n",
				__func__, error, len,
				so->so_rcv.sb_hiwat, so->so_rcv.sb_cc);

		socket_unlock(so, 1);
	}
	if (m_remain) {
		*m_remain = m;

		if (m != NULL && socket_debug && so != NULL &&
		    (so->so_options & SO_DEBUG)) {
			struct mbuf *n;

			printf("%s m_list %llx\n", __func__,
			    (uint64_t) VM_KERNEL_ADDRPERM(m_list));
			for (n = m; n != NULL; n = n->m_nextpkt)
				printf(" remain %llx m_next %llx\n",
				    (uint64_t) VM_KERNEL_ADDRPERM(n),
				    (uint64_t) VM_KERNEL_ADDRPERM(n->m_next));
		}
	} else {
		if (m != NULL)
			m_freem_list(m);
	}
	if (error != 0)
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fail);
	return (error);
}

errno_t
ctl_enqueuedata(void *kctlref, u_int32_t unit, void *data, size_t len,
    u_int32_t flags)
{
	struct socket 	*so;
	struct mbuf 	*m;
	errno_t		error = 0;
	unsigned int 	num_needed;
	struct mbuf 	*n;
	size_t		curlen = 0;
	u_int32_t	kctlflags;

	so = kcb_find_socket(kctlref, unit, &kctlflags);
	if (so == NULL) {
		return (EINVAL);
	}

	if (ctl_rcvbspace(so, len, kctlflags, flags) != 0) {
		error = ENOBUFS;
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fullsock);
		goto bye;
	}

	num_needed = 1;
	m = m_allocpacket_internal(&num_needed, len, NULL, M_NOWAIT, 1, 0);
	if (m == NULL) {
		kctlstat.kcs_enqdata_mb_alloc_fail++;
		if (ctl_debug)
			printf("%s: m_allocpacket_internal(%lu) failed\n",
			    __func__, len);
		error = ENOMEM;
		goto bye;
	}

	for (n = m; n != NULL; n = n->m_next) {
		size_t mlen = mbuf_maxlen(n);

		if (mlen + curlen > len)
			mlen = len - curlen;
		n->m_len = mlen;
		bcopy((char *)data + curlen, n->m_data, mlen);
		curlen += mlen;
	}
	mbuf_pkthdr_setlen(m, curlen);

	if ((flags & CTL_DATA_EOR))
		m->m_flags |= M_EOR;
	so_recv_data_stat(so, m, 0);
	if (sbappend(&so->so_rcv, m) != 0) {
		if ((flags & CTL_DATA_NOWAKEUP) == 0)
			sorwakeup(so);
	} else {
		kctlstat.kcs_enqdata_sbappend_fail++;
		error = ENOBUFS;
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fullsock);
	}

bye:
	if (ctl_debug && error != 0 && (flags & CTL_DATA_CRIT))
		printf("%s - crit data err %d len %d hiwat %d cc: %d\n",
			__func__, error, (int)len,
			so->so_rcv.sb_hiwat, so->so_rcv.sb_cc);

	socket_unlock(so, 1);
	if (error != 0)
		OSIncrementAtomic64((SInt64 *)&kctlstat.kcs_enqueue_fail);
	return (error);
}

errno_t
ctl_getenqueuepacketcount(kern_ctl_ref kctlref, u_int32_t unit, u_int32_t *pcnt)
{
	struct socket 	*so;
	u_int32_t cnt;
	struct mbuf *m1;

	if (pcnt == NULL)
		return (EINVAL);

	so = kcb_find_socket(kctlref, unit, NULL);
	if (so == NULL) {
		return (EINVAL);
	}

	cnt = 0;
	m1 = so->so_rcv.sb_mb;
	while (m1 != NULL) {
		if (m1->m_type == MT_DATA ||
		    m1->m_type == MT_HEADER ||
		    m1->m_type == MT_OOBDATA)
			cnt += 1;
		m1 = m1->m_nextpkt;
	}
	*pcnt = cnt;

	socket_unlock(so, 1);

	return (0);
}

errno_t
ctl_getenqueuespace(kern_ctl_ref kctlref, u_int32_t unit, size_t *space)
{
	struct socket 	*so;
	long avail;

	if (space == NULL)
		return (EINVAL);

	so = kcb_find_socket(kctlref, unit, NULL);
	if (so == NULL) {
		return (EINVAL);
	}

	avail = sbspace(&so->so_rcv);
	*space = (avail < 0) ? 0 : avail;
	socket_unlock(so, 1);

	return (0);
}

errno_t
ctl_getenqueuereadable(kern_ctl_ref kctlref, u_int32_t unit,
    u_int32_t *difference)
{
	struct socket 	*so;

	if (difference == NULL)
		return (EINVAL);

	so = kcb_find_socket(kctlref, unit, NULL);
	if (so == NULL) {
		return (EINVAL);
	}

	if (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat) {
		*difference = 0;
	} else {
		*difference = (so->so_rcv.sb_lowat - so->so_rcv.sb_cc);
	}
	socket_unlock(so, 1);

	return (0);
}

static int
ctl_ctloutput(struct socket *so, struct sockopt *sopt)
{
	struct ctl_cb 	*kcb = (struct ctl_cb *)so->so_pcb;
	struct kctl	*kctl;
	int 	error = 0;
	void 	*data = NULL;
	size_t	len;

	if (sopt->sopt_level != SYSPROTO_CONTROL) {
		return (EINVAL);
	}

	if (kcb == NULL)	/* sanity check */
		return (ENOTCONN);

	if ((kctl = kcb->kctl) == NULL)
		return (EINVAL);

	switch (sopt->sopt_dir) {
		case SOPT_SET:
			if (kctl->setopt == NULL)
				return (ENOTSUP);
			if (sopt->sopt_valsize != 0) {
				MALLOC(data, void *, sopt->sopt_valsize, M_TEMP,
					M_WAITOK | M_ZERO);
				if (data == NULL)
					return (ENOMEM);
				error = sooptcopyin(sopt, data,
				    sopt->sopt_valsize, sopt->sopt_valsize);
			}
			if (error == 0) {
				socket_unlock(so, 0);
				error = (*kctl->setopt)(kctl->kctlref,
				    kcb->sac.sc_unit, kcb->userdata, sopt->sopt_name,
				    data, sopt->sopt_valsize);
				socket_lock(so, 0);
			}

			if (data != NULL)
				FREE(data, M_TEMP);
			break;

		case SOPT_GET:
			if (kctl->getopt == NULL)
				return (ENOTSUP);

			if (sopt->sopt_valsize && sopt->sopt_val) {
				MALLOC(data, void *, sopt->sopt_valsize, M_TEMP,
					M_WAITOK | M_ZERO);
				if (data == NULL)
					return (ENOMEM);
				/*
				 * 4108337 - copy user data in case the
				 * kernel control needs it
				 */
				error = sooptcopyin(sopt, data,
					sopt->sopt_valsize, sopt->sopt_valsize);
			}

			if (error == 0) {
				len = sopt->sopt_valsize;
				socket_unlock(so, 0);
				error = (*kctl->getopt)(kctl->kctlref, kcb->sac.sc_unit,
						kcb->userdata, sopt->sopt_name,
						data, &len);
				if (data != NULL && len > sopt->sopt_valsize)
					panic_plain("ctl_ctloutput: ctl %s returned "
					    "len (%lu) > sopt_valsize (%lu)\n",
					    kcb->kctl->name, len,
					    sopt->sopt_valsize);
				socket_lock(so, 0);
				if (error == 0) {
					if (data != NULL)
						error = sooptcopyout(sopt, data, len);
					else
						sopt->sopt_valsize = len;
				}
			}
			if (data != NULL)
				FREE(data, M_TEMP);
			break;
	}
	return (error);
}

static int
ctl_ioctl(struct socket *so, u_long cmd, caddr_t data,
	struct ifnet *ifp, struct proc *p)
{
#pragma unused(so, ifp, p)
	int 	error = ENOTSUP;

	switch (cmd) {
		/* get the number of controllers */
		case CTLIOCGCOUNT: {
			struct kctl	*kctl;
			u_int32_t n = 0;

			lck_mtx_lock(ctl_mtx);
			TAILQ_FOREACH(kctl, &ctl_head, next)
				n++;
			lck_mtx_unlock(ctl_mtx);

			bcopy(&n, data, sizeof (n));
			error = 0;
			break;
		}
		case CTLIOCGINFO: {
			struct ctl_info ctl_info;
			struct kctl 	*kctl = 0;
			size_t name_len;

			bcopy(data, &ctl_info, sizeof (ctl_info));
			name_len = strnlen(ctl_info.ctl_name, MAX_KCTL_NAME);

			if (name_len == 0 || name_len + 1 > MAX_KCTL_NAME) {
				error = EINVAL;
				break;
			}
			lck_mtx_lock(ctl_mtx);
			kctl = ctl_find_by_name(ctl_info.ctl_name);
			lck_mtx_unlock(ctl_mtx);
			if (kctl == 0) {
				error = ENOENT;
				break;
			}
			ctl_info.ctl_id = kctl->id;
			bcopy(&ctl_info, data, sizeof (ctl_info));
			error = 0;
			break;
		}

		/* add controls to get list of NKEs */

	}

	return (error);
}

static void
kctl_tbl_grow()
{
	struct kctl **new_table;
	uintptr_t new_size;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	if (kctl_tbl_growing) {
		/* Another thread is allocating */
		kctl_tbl_growing_waiting++;

		do {
			(void) msleep((caddr_t) &kctl_tbl_growing, ctl_mtx,
				PSOCK | PCATCH, "kctl_tbl_growing", 0);
		} while (kctl_tbl_growing);
		kctl_tbl_growing_waiting--;
	}
	/* Another thread grew the table */
	if (kctl_table != NULL && kctl_tbl_count < kctl_tbl_size)
		return;

	/* Verify we have a sane size */
	if (kctl_tbl_size + KCTL_TBL_INC >= UINT16_MAX) {
		kctlstat.kcs_tbl_size_too_big++;
		if (ctl_debug)
			printf("%s kctl_tbl_size %lu too big\n",
			    __func__, kctl_tbl_size);
		return;
	}
	kctl_tbl_growing = 1;

	new_size = kctl_tbl_size + KCTL_TBL_INC;

	lck_mtx_unlock(ctl_mtx);
	new_table = _MALLOC(sizeof(struct kctl *) * new_size,
	    M_TEMP, M_WAIT | M_ZERO);
	lck_mtx_lock(ctl_mtx);

	if (new_table != NULL) {
		if (kctl_table != NULL) {
			bcopy(kctl_table, new_table,
			    kctl_tbl_size * sizeof(struct kctl *));

			_FREE(kctl_table, M_TEMP);
		}
		kctl_table = new_table;
		kctl_tbl_size = new_size;
	}

	kctl_tbl_growing = 0;

	if (kctl_tbl_growing_waiting) {
		wakeup(&kctl_tbl_growing);
	}
}

#define KCTLREF_INDEX_MASK 0x0000FFFF
#define KCTLREF_GENCNT_MASK 0xFFFF0000
#define KCTLREF_GENCNT_SHIFT 16

static kern_ctl_ref
kctl_make_ref(struct kctl *kctl)
{
	uintptr_t i;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	if (kctl_tbl_count >= kctl_tbl_size)
		kctl_tbl_grow();

	kctl->kctlref = NULL;
	for (i = 0; i < kctl_tbl_size; i++) {
		if (kctl_table[i] == NULL) {
			uintptr_t ref;

			/*
			 * Reference is index plus one
			 */
			kctl_ref_gencnt += 1;

			/*
			 * Add generation count as salt to reference to prevent
			 * use after deregister
			 */
			ref = ((kctl_ref_gencnt << KCTLREF_GENCNT_SHIFT) & 
			    KCTLREF_GENCNT_MASK) +
			    ((i + 1) & KCTLREF_INDEX_MASK);

			kctl->kctlref = (void *)(ref);
			kctl_table[i] = kctl;
			kctl_tbl_count++;
			break;
		}
	}

	if (kctl->kctlref == NULL)
		panic("%s no space in table", __func__);

	if (ctl_debug > 0)
		printf("%s %p for %p\n",
			__func__, kctl->kctlref, kctl);

	return (kctl->kctlref);
}

static void
kctl_delete_ref(kern_ctl_ref kctlref)
{
	/*
	 * Reference is index plus one
	 */
	uintptr_t i = (((uintptr_t)kctlref) & KCTLREF_INDEX_MASK) - 1;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	if (i < kctl_tbl_size) {
		struct kctl *kctl = kctl_table[i];

		if (kctl->kctlref == kctlref) {
			kctl_table[i] = NULL;
			kctl_tbl_count--;
		} else {
			kctlstat.kcs_bad_kctlref++;
		}
	} else {
		kctlstat.kcs_bad_kctlref++;
	}
}

static struct kctl *
kctl_from_ref(kern_ctl_ref kctlref)
{
	/*
	 * Reference is index plus one
	 */
	uintptr_t i = (((uintptr_t)kctlref) & KCTLREF_INDEX_MASK) - 1;
	struct kctl *kctl = NULL;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	if (i >= kctl_tbl_size) {
		kctlstat.kcs_bad_kctlref++;
		return (NULL);
	}
	kctl = kctl_table[i];
	if (kctl->kctlref != kctlref) {
		kctlstat.kcs_bad_kctlref++;
		return (NULL);
	}
	return (kctl);
}

/*
 * Register/unregister a NKE
 */
errno_t
ctl_register(struct kern_ctl_reg *userkctl, kern_ctl_ref *kctlref)
{
	struct kctl 	*kctl = NULL;
	struct kctl 	*kctl_next = NULL;
	u_int32_t	id = 1;
	size_t		name_len;
	int		is_extended = 0;

	if (userkctl == NULL)	/* sanity check */
		return (EINVAL);
	if (userkctl->ctl_connect == NULL)
		return (EINVAL);
	name_len = strlen(userkctl->ctl_name);
	if (name_len == 0 || name_len + 1 > MAX_KCTL_NAME)
		return (EINVAL);

	MALLOC(kctl, struct kctl *, sizeof(*kctl), M_TEMP, M_WAITOK);
	if (kctl == NULL)
		return (ENOMEM);
	bzero((char *)kctl, sizeof(*kctl));

	lck_mtx_lock(ctl_mtx);

	if (kctl_make_ref(kctl) == NULL) {
		lck_mtx_unlock(ctl_mtx);
		FREE(kctl, M_TEMP);
		return (ENOMEM);
	}

	/*
	 * Kernel Control IDs
	 *
	 * CTL_FLAG_REG_ID_UNIT indicates the control ID and unit number are
	 * static. If they do not exist, add them to the list in order. If the
	 * flag is not set, we must find a new unique value. We assume the
	 * list is in order. We find the last item in the list and add one. If
	 * this leads to wrapping the id around, we start at the front of the
	 * list and look for a gap.
	 */

	if ((userkctl->ctl_flags & CTL_FLAG_REG_ID_UNIT) == 0) {
		/* Must dynamically assign an unused ID */

		/* Verify the same name isn't already registered */
		if (ctl_find_by_name(userkctl->ctl_name) != NULL) {
			kctl_delete_ref(kctl->kctlref);
			lck_mtx_unlock(ctl_mtx);
			FREE(kctl, M_TEMP);
			return (EEXIST);
		}

		/* Start with 1 in case the list is empty */
		id = 1;
		kctl_next = TAILQ_LAST(&ctl_head, kctl_list);

		if (kctl_next != NULL) {
			/* List was not empty, add one to the last item */
			id = kctl_next->id + 1;
			kctl_next = NULL;

			/*
			 * If this wrapped the id number, start looking at
			 * the front of the list for an unused id.
			 */
			if (id == 0) {
				/* Find the next unused ID */
				id = 1;

				TAILQ_FOREACH(kctl_next, &ctl_head, next) {
					if (kctl_next->id > id) {
						/* We found a gap */
						break;
					}

					id = kctl_next->id + 1;
				}
			}
		}

		userkctl->ctl_id = id;
		kctl->id = id;
		kctl->reg_unit = -1;
	} else {
		TAILQ_FOREACH(kctl_next, &ctl_head, next) {
			if (kctl_next->id > userkctl->ctl_id)
				break;
		}

		if (ctl_find_by_id_unit(userkctl->ctl_id, userkctl->ctl_unit)) {
			kctl_delete_ref(kctl->kctlref);
			lck_mtx_unlock(ctl_mtx);
			FREE(kctl, M_TEMP);
			return (EEXIST);
		}
		kctl->id = userkctl->ctl_id;
		kctl->reg_unit = userkctl->ctl_unit;
	}

	is_extended = (userkctl->ctl_flags & CTL_FLAG_REG_EXTENDED);

	strlcpy(kctl->name, userkctl->ctl_name, MAX_KCTL_NAME);
	kctl->flags = userkctl->ctl_flags;

	/*
	 * Let the caller know the default send and receive sizes
	 */
	if (userkctl->ctl_sendsize == 0) {
		kctl->sendbufsize = CTL_SENDSIZE;
		userkctl->ctl_sendsize = kctl->sendbufsize;
	} else {
		kctl->sendbufsize = userkctl->ctl_sendsize;
	}
	if (userkctl->ctl_recvsize == 0) {
		kctl->recvbufsize = CTL_RECVSIZE;
		userkctl->ctl_recvsize = kctl->recvbufsize;
	} else {
		kctl->recvbufsize = userkctl->ctl_recvsize;
	}

	kctl->bind = userkctl->ctl_bind;
	kctl->connect = userkctl->ctl_connect;
	kctl->disconnect = userkctl->ctl_disconnect;
	kctl->send = userkctl->ctl_send;
	kctl->setopt = userkctl->ctl_setopt;
	kctl->getopt = userkctl->ctl_getopt;
	if (is_extended) {
		kctl->rcvd = userkctl->ctl_rcvd;
		kctl->send_list = userkctl->ctl_send_list;
	}

	TAILQ_INIT(&kctl->kcb_head);

	if (kctl_next)
		TAILQ_INSERT_BEFORE(kctl_next, kctl, next);
	else
		TAILQ_INSERT_TAIL(&ctl_head, kctl, next);

	kctlstat.kcs_reg_count++;
	kctlstat.kcs_gencnt++;

	lck_mtx_unlock(ctl_mtx);

	*kctlref = kctl->kctlref;

	ctl_post_msg(KEV_CTL_REGISTERED, kctl->id);
	return (0);
}

errno_t
ctl_deregister(void *kctlref)
{
	struct kctl		*kctl;

	lck_mtx_lock(ctl_mtx);
	if ((kctl = kctl_from_ref(kctlref)) == NULL) {
		kctlstat.kcs_bad_kctlref++;
		lck_mtx_unlock(ctl_mtx);
		if (ctl_debug != 0)
			printf("%s invalid kctlref %p\n",
				__func__, kctlref);
		return (EINVAL);
	}

	if (!TAILQ_EMPTY(&kctl->kcb_head)) {
		lck_mtx_unlock(ctl_mtx);
		return (EBUSY);
	}

	TAILQ_REMOVE(&ctl_head, kctl, next);

	kctlstat.kcs_reg_count--;
	kctlstat.kcs_gencnt++;

	kctl_delete_ref(kctl->kctlref);
	lck_mtx_unlock(ctl_mtx);

	ctl_post_msg(KEV_CTL_DEREGISTERED, kctl->id);
	FREE(kctl, M_TEMP);
	return (0);
}

/*
 * Must be called with global ctl_mtx lock taked
 */
static struct kctl *
ctl_find_by_name(const char *name)
{
	struct kctl 	*kctl;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	TAILQ_FOREACH(kctl, &ctl_head, next)
		if (strncmp(kctl->name, name, sizeof(kctl->name)) == 0)
			return (kctl);

	return (NULL);
}

u_int32_t
ctl_id_by_name(const char *name)
{
	u_int32_t	ctl_id = 0;
	struct kctl	*kctl;

	lck_mtx_lock(ctl_mtx);
	kctl = ctl_find_by_name(name);
	if (kctl)
		ctl_id = kctl->id;
	lck_mtx_unlock(ctl_mtx);

	return (ctl_id);
}

errno_t
ctl_name_by_id(u_int32_t id, char *out_name, size_t maxsize)
{
	int 		found = 0;
	struct kctl *kctl;

	lck_mtx_lock(ctl_mtx);
	TAILQ_FOREACH(kctl, &ctl_head, next) {
		if (kctl->id == id)
			break;
	}

	if (kctl) {
		if (maxsize > MAX_KCTL_NAME)
			maxsize = MAX_KCTL_NAME;
		strlcpy(out_name, kctl->name, maxsize);
		found = 1;
	}
	lck_mtx_unlock(ctl_mtx);

	return (found ? 0 : ENOENT);
}

/*
 * Must be called with global ctl_mtx lock taked
 *
 */
static struct kctl *
ctl_find_by_id_unit(u_int32_t id, u_int32_t unit)
{
	struct kctl 	*kctl;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	TAILQ_FOREACH(kctl, &ctl_head, next) {
		if (kctl->id == id && (kctl->flags & CTL_FLAG_REG_ID_UNIT) == 0)
			return (kctl);
		else if (kctl->id == id && kctl->reg_unit == unit)
			return (kctl);
	}
	return (NULL);
}

/*
 * Must be called with kernel controller lock taken
 */
static struct ctl_cb *
kcb_find(struct kctl *kctl, u_int32_t unit)
{
	struct ctl_cb 	*kcb;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_OWNED);

	TAILQ_FOREACH(kcb, &kctl->kcb_head, next)
		if (kcb->sac.sc_unit == unit)
			return (kcb);

	return (NULL);
}

static struct socket *
kcb_find_socket(kern_ctl_ref kctlref, u_int32_t unit, u_int32_t *kctlflags)
{
	struct socket *so = NULL;
	struct ctl_cb	*kcb;
	void *lr_saved;
	struct kctl *kctl;
	int i;

	lr_saved = __builtin_return_address(0);

	lck_mtx_lock(ctl_mtx);
	/*
	 * First validate the kctlref
	 */
	if ((kctl = kctl_from_ref(kctlref)) == NULL) {
		kctlstat.kcs_bad_kctlref++;
		lck_mtx_unlock(ctl_mtx);
		if (ctl_debug != 0)
			printf("%s invalid kctlref %p\n",
				__func__, kctlref);
		return (NULL);
	}

	kcb = kcb_find(kctl, unit);
	if (kcb == NULL || kcb->kctl != kctl || (so = kcb->so) == NULL) {
		lck_mtx_unlock(ctl_mtx);
		return (NULL);
	}
	/*
	 * This prevents the socket from being closed
	 */
	kcb->usecount++;
	/*
	 * Respect lock ordering: socket before ctl_mtx
	 */
	lck_mtx_unlock(ctl_mtx);

	socket_lock(so, 1);
	/*
	 * The socket lock history is more useful if we store
	 * the address of the caller.
	 */
	i = (so->next_lock_lr + SO_LCKDBG_MAX - 1) % SO_LCKDBG_MAX;
	so->lock_lr[i] = lr_saved;

	lck_mtx_lock(ctl_mtx);

	if ((kctl = kctl_from_ref(kctlref)) == NULL || kcb->kctl == NULL) {
		lck_mtx_unlock(ctl_mtx);
		socket_unlock(so, 1);
		so = NULL;
		lck_mtx_lock(ctl_mtx);
	} else if (kctlflags != NULL) {
		*kctlflags = kctl->flags;
	}

	kcb->usecount--;
	if (kcb->usecount == 0)
		wakeup((event_t)&kcb->usecount);

	lck_mtx_unlock(ctl_mtx);

	return (so);
}

static void
ctl_post_msg(u_int32_t event_code, u_int32_t id)
{
	struct ctl_event_data  	ctl_ev_data;
	struct kev_msg  		ev_msg;

	lck_mtx_assert(ctl_mtx, LCK_MTX_ASSERT_NOTOWNED);

	bzero(&ev_msg, sizeof(struct kev_msg));
	ev_msg.vendor_code = KEV_VENDOR_APPLE;

	ev_msg.kev_class = KEV_SYSTEM_CLASS;
	ev_msg.kev_subclass = KEV_CTL_SUBCLASS;
	ev_msg.event_code = event_code;

	/* common nke subclass data */
	bzero(&ctl_ev_data, sizeof(ctl_ev_data));
	ctl_ev_data.ctl_id = id;
	ev_msg.dv[0].data_ptr = &ctl_ev_data;
	ev_msg.dv[0].data_length = sizeof(ctl_ev_data);

	ev_msg.dv[1].data_length = 0;

	kev_post_msg(&ev_msg);
}

static int
ctl_lock(struct socket *so, int refcount, void *lr)
{
	void *lr_saved;

	if (lr == NULL)
		lr_saved = __builtin_return_address(0);
	else
		lr_saved = lr;

	if (so->so_pcb != NULL) {
		lck_mtx_lock(((struct ctl_cb *)so->so_pcb)->mtx);
	} else  {
		panic("ctl_lock: so=%p NO PCB! lr=%p lrh= %s\n",
		    so, lr_saved, solockhistory_nr(so));
		/* NOTREACHED */
	}

	if (so->so_usecount < 0) {
		panic("ctl_lock: so=%p so_pcb=%p lr=%p ref=%x lrh= %s\n",
			so, so->so_pcb, lr_saved, so->so_usecount,
			solockhistory_nr(so));
		/* NOTREACHED */
	}

	if (refcount)
		so->so_usecount++;

	so->lock_lr[so->next_lock_lr] = lr_saved;
	so->next_lock_lr = (so->next_lock_lr+1) % SO_LCKDBG_MAX;
	return (0);
}

static int
ctl_unlock(struct socket *so, int refcount, void *lr)
{
	void *lr_saved;
	lck_mtx_t *mutex_held;

	if (lr == NULL)
		lr_saved = __builtin_return_address(0);
	else
		lr_saved = lr;

#if (MORE_KCTLLOCK_DEBUG && (DEVELOPMENT || DEBUG))
	printf("ctl_unlock: so=%llx sopcb=%x lock=%llx ref=%u lr=%llx\n",
	    (uint64_t)VM_KERNEL_ADDRPERM(so),
	    (uint64_t)VM_KERNEL_ADDRPERM(so->so_pcb,
	    (uint64_t)VM_KERNEL_ADDRPERM(((struct ctl_cb *)so->so_pcb)->mtx),
	    so->so_usecount, (uint64_t)VM_KERNEL_ADDRPERM(lr_saved));
#endif /* (MORE_KCTLLOCK_DEBUG && (DEVELOPMENT || DEBUG)) */
	if (refcount)
		so->so_usecount--;

	if (so->so_usecount < 0) {
		panic("ctl_unlock: so=%p usecount=%x lrh= %s\n",
		    so, so->so_usecount, solockhistory_nr(so));
		/* NOTREACHED */
	}
	if (so->so_pcb == NULL) {
		panic("ctl_unlock: so=%p NO PCB usecount=%x lr=%p lrh= %s\n",
			so, so->so_usecount, (void *)lr_saved,
			solockhistory_nr(so));
		/* NOTREACHED */
	}
	mutex_held = ((struct ctl_cb *)so->so_pcb)->mtx;

	lck_mtx_assert(mutex_held, LCK_MTX_ASSERT_OWNED);
	so->unlock_lr[so->next_unlock_lr] = lr_saved;
	so->next_unlock_lr = (so->next_unlock_lr+1) % SO_LCKDBG_MAX;
	lck_mtx_unlock(mutex_held);

	if (so->so_usecount == 0)
		ctl_sofreelastref(so);

	return (0);
}

static lck_mtx_t *
ctl_getlock(struct socket *so, int flags)
{
#pragma unused(flags)
	struct ctl_cb *kcb = (struct ctl_cb *)so->so_pcb;

	if (so->so_pcb)  {
		if (so->so_usecount < 0)
			panic("ctl_getlock: so=%p usecount=%x lrh= %s\n",
			    so, so->so_usecount, solockhistory_nr(so));
		return (kcb->mtx);
	} else {
		panic("ctl_getlock: so=%p NULL NO so_pcb %s\n",
		    so, solockhistory_nr(so));
		return (so->so_proto->pr_domain->dom_mtx);
	}
}

__private_extern__ int
kctl_reg_list SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
	int error = 0;
	int n, i;
	struct xsystmgen xsg;
	void *buf = NULL;
	struct kctl *kctl;
	size_t item_size = ROUNDUP64(sizeof (struct xkctl_reg));

	buf = _MALLOC(item_size, M_TEMP, M_WAITOK | M_ZERO);
	if (buf == NULL)
		return (ENOMEM);

	lck_mtx_lock(ctl_mtx);

	n = kctlstat.kcs_reg_count;

	if (req->oldptr == USER_ADDR_NULL) {
		req->oldidx = (n + n/8) * sizeof(struct xkctl_reg);
		goto done;
	}
	if (req->newptr != USER_ADDR_NULL) {
		error = EPERM;
		goto done;
	}
	bzero(&xsg, sizeof (xsg));
	xsg.xg_len = sizeof (xsg);
	xsg.xg_count = n;
	xsg.xg_gen = kctlstat.kcs_gencnt;
	xsg.xg_sogen = so_gencnt;
	error = SYSCTL_OUT(req, &xsg, sizeof (xsg));
	if (error) {
		goto done;
	}
	/*
	 * We are done if there is no pcb
	 */
	if (n == 0) {
		goto done;
	}

	i = 0;
	for (i = 0, kctl = TAILQ_FIRST(&ctl_head);
	    i < n && kctl != NULL;
	    i++, kctl = TAILQ_NEXT(kctl, next)) {
		struct xkctl_reg *xkr = (struct xkctl_reg *)buf;
		struct ctl_cb *kcb;
		u_int32_t pcbcount = 0;

		TAILQ_FOREACH(kcb, &kctl->kcb_head, next)
			pcbcount++;

		bzero(buf, item_size);

		xkr->xkr_len = sizeof(struct xkctl_reg);
		xkr->xkr_kind = XSO_KCREG;
		xkr->xkr_id = kctl->id;
		xkr->xkr_reg_unit = kctl->reg_unit;
		xkr->xkr_flags = kctl->flags;
		xkr->xkr_kctlref = (uint64_t)(kctl->kctlref);
		xkr->xkr_recvbufsize = kctl->recvbufsize;
		xkr->xkr_sendbufsize = kctl->sendbufsize;
		xkr->xkr_lastunit = kctl->lastunit;
		xkr->xkr_pcbcount = pcbcount;
		xkr->xkr_connect = (uint64_t)VM_KERNEL_UNSLIDE(kctl->connect);
		xkr->xkr_disconnect =
		    (uint64_t)VM_KERNEL_UNSLIDE(kctl->disconnect);
		xkr->xkr_send = (uint64_t)VM_KERNEL_UNSLIDE(kctl->send);
		xkr->xkr_send_list =
		    (uint64_t)VM_KERNEL_UNSLIDE(kctl->send_list);
		xkr->xkr_setopt = (uint64_t)VM_KERNEL_UNSLIDE(kctl->setopt);
		xkr->xkr_getopt = (uint64_t)VM_KERNEL_UNSLIDE(kctl->getopt);
		xkr->xkr_rcvd = (uint64_t)VM_KERNEL_UNSLIDE(kctl->rcvd);
		strlcpy(xkr->xkr_name, kctl->name, sizeof(xkr->xkr_name));

		error = SYSCTL_OUT(req, buf, item_size);
	}

	if (error == 0) {
		/*
		 * Give the user an updated idea of our state.
		 * If the generation differs from what we told
		 * her before, she knows that something happened
		 * while we were processing this request, and it
		 * might be necessary to retry.
		 */
		bzero(&xsg, sizeof (xsg));
		xsg.xg_len = sizeof (xsg);
		xsg.xg_count = n;
		xsg.xg_gen = kctlstat.kcs_gencnt;
		xsg.xg_sogen = so_gencnt;
		error = SYSCTL_OUT(req, &xsg, sizeof (xsg));
		if (error) {
			goto done;
		}
	}

done:
	lck_mtx_unlock(ctl_mtx);

	if (buf != NULL)
		FREE(buf, M_TEMP);

	return (error);
}

__private_extern__ int
kctl_pcblist SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
	int error = 0;
	int n, i;
	struct xsystmgen xsg;
	void *buf = NULL;
	struct kctl *kctl;
	size_t item_size = ROUNDUP64(sizeof (struct xkctlpcb)) +
		ROUNDUP64(sizeof (struct xsocket_n)) +
		2 * ROUNDUP64(sizeof (struct xsockbuf_n)) +
		ROUNDUP64(sizeof (struct xsockstat_n));

	buf = _MALLOC(item_size, M_TEMP, M_WAITOK | M_ZERO);
	if (buf == NULL)
		return (ENOMEM);

	lck_mtx_lock(ctl_mtx);

	n = kctlstat.kcs_pcbcount;

	if (req->oldptr == USER_ADDR_NULL) {
		req->oldidx = (n + n/8) * item_size;
		goto done;
	}
	if (req->newptr != USER_ADDR_NULL) {
		error = EPERM;
		goto done;
	}
	bzero(&xsg, sizeof (xsg));
	xsg.xg_len = sizeof (xsg);
	xsg.xg_count = n;
	xsg.xg_gen = kctlstat.kcs_gencnt;
	xsg.xg_sogen = so_gencnt;
	error = SYSCTL_OUT(req, &xsg, sizeof (xsg));
	if (error) {
		goto done;
	}
	/*
	 * We are done if there is no pcb
	 */
	if (n == 0) {
		goto done;
	}

	i = 0;
	for (i = 0, kctl = TAILQ_FIRST(&ctl_head);
	    i < n && kctl != NULL;
	    kctl = TAILQ_NEXT(kctl, next)) {
		struct ctl_cb *kcb;

		for (kcb = TAILQ_FIRST(&kctl->kcb_head);
		    i < n && kcb != NULL;
		    i++, kcb = TAILQ_NEXT(kcb, next)) {
			struct xkctlpcb *xk = (struct xkctlpcb *)buf;
			struct xsocket_n *xso = (struct xsocket_n *)
				ADVANCE64(xk, sizeof (*xk));
			struct xsockbuf_n *xsbrcv = (struct xsockbuf_n *)
				ADVANCE64(xso, sizeof (*xso));
			struct xsockbuf_n *xsbsnd = (struct xsockbuf_n *)
				ADVANCE64(xsbrcv, sizeof (*xsbrcv));
			struct xsockstat_n *xsostats = (struct xsockstat_n *)
				ADVANCE64(xsbsnd, sizeof (*xsbsnd));

			bzero(buf, item_size);

			xk->xkp_len = sizeof(struct xkctlpcb);
			xk->xkp_kind = XSO_KCB;
			xk->xkp_unit = kcb->sac.sc_unit;
			xk->xkp_kctpcb = (uint64_t)VM_KERNEL_ADDRPERM(kcb);
			xk->xkp_kctlref = (uint64_t)VM_KERNEL_ADDRPERM(kctl);
			xk->xkp_kctlid = kctl->id;
			strlcpy(xk->xkp_kctlname, kctl->name,
			    sizeof(xk->xkp_kctlname));

			sotoxsocket_n(kcb->so, xso);
			sbtoxsockbuf_n(kcb->so ?
				&kcb->so->so_rcv : NULL, xsbrcv);
			sbtoxsockbuf_n(kcb->so ?
				&kcb->so->so_snd : NULL, xsbsnd);
			sbtoxsockstat_n(kcb->so, xsostats);

			error = SYSCTL_OUT(req, buf, item_size);
		}
	}

	if (error == 0) {
		/*
		 * Give the user an updated idea of our state.
		 * If the generation differs from what we told
		 * her before, she knows that something happened
		 * while we were processing this request, and it
		 * might be necessary to retry.
		 */
		bzero(&xsg, sizeof (xsg));
		xsg.xg_len = sizeof (xsg);
		xsg.xg_count = n;
		xsg.xg_gen = kctlstat.kcs_gencnt;
		xsg.xg_sogen = so_gencnt;
		error = SYSCTL_OUT(req, &xsg, sizeof (xsg));
		if (error) {
			goto done;
		}
	}

done:
	lck_mtx_unlock(ctl_mtx);

	return (error);
}

int
kctl_getstat SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
	int error = 0;

	lck_mtx_lock(ctl_mtx);

	if (req->newptr != USER_ADDR_NULL) {
		error = EPERM;
		goto done;
	}
	if (req->oldptr == USER_ADDR_NULL) {
		req->oldidx = sizeof(struct kctlstat);
		goto done;
	}

	error = SYSCTL_OUT(req, &kctlstat,
	    MIN(sizeof(struct kctlstat), req->oldlen));
done:
	lck_mtx_unlock(ctl_mtx);
	return (error);
}

void
kctl_fill_socketinfo(struct socket *so, struct socket_info *si)
{
	struct ctl_cb *kcb = (struct ctl_cb *)so->so_pcb;
	struct kern_ctl_info *kcsi =
	    &si->soi_proto.pri_kern_ctl;
	struct kctl *kctl = kcb->kctl;

	si->soi_kind = SOCKINFO_KERN_CTL;

	if (kctl == 0)
		return;

	kcsi->kcsi_id = kctl->id;
	kcsi->kcsi_reg_unit = kctl->reg_unit;
	kcsi->kcsi_flags = kctl->flags;
	kcsi->kcsi_recvbufsize = kctl->recvbufsize;
	kcsi->kcsi_sendbufsize = kctl->sendbufsize;
	kcsi->kcsi_unit = kcb->sac.sc_unit;
	strlcpy(kcsi->kcsi_name, kctl->name, MAX_KCTL_NAME);
}
