/*
 * Copyright (c) 2012-2017 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@
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/mcache.h>
#include <sys/syslog.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/proc_internal.h>

#include <mach/boolean.h>
#include <kern/zalloc.h>
#include <kern/locks.h>

#include <netinet/mp_pcb.h>
#include <netinet/mptcp_var.h>
#include <netinet6/in6_pcb.h>

static LCK_GRP_DECLARE(mp_lock_grp, "multipath");
static LCK_ATTR_DECLARE(mp_lock_attr, 0, 0);
static LCK_MTX_DECLARE_ATTR(mp_lock, &mp_lock_grp, &mp_lock_attr);
static LCK_MTX_DECLARE_ATTR(mp_timeout_lock, &mp_lock_grp, &mp_lock_attr);

static TAILQ_HEAD(, mppcbinfo) mppi_head = TAILQ_HEAD_INITIALIZER(mppi_head);

static boolean_t mp_timeout_run;        /* MP timer is scheduled to run */
static boolean_t mp_garbage_collecting;
static boolean_t mp_ticking;
static void mp_sched_timeout(void);
static void mp_timeout(void *);

static void
mpp_lock_assert_held(struct mppcb *mp)
{
#if !MACH_ASSERT
#pragma unused(mp)
#endif
	LCK_MTX_ASSERT(&mp->mpp_lock, LCK_MTX_ASSERT_OWNED);
}

static void
mp_timeout(void *arg)
{
#pragma unused(arg)
	struct mppcbinfo *mppi;
	boolean_t t, gc;
	uint32_t t_act = 0;
	uint32_t gc_act = 0;

	/*
	 * Update coarse-grained networking timestamp (in sec.); the idea
	 * is to piggy-back on the timeout callout to update the counter
	 * returnable via net_uptime().
	 */
	net_update_uptime();

	lck_mtx_lock_spin(&mp_timeout_lock);
	gc = mp_garbage_collecting;
	mp_garbage_collecting = FALSE;

	t = mp_ticking;
	mp_ticking = FALSE;

	if (gc || t) {
		lck_mtx_unlock(&mp_timeout_lock);

		lck_mtx_lock(&mp_lock);
		TAILQ_FOREACH(mppi, &mppi_head, mppi_entry) {
			if ((gc && mppi->mppi_gc != NULL) ||
			    (t && mppi->mppi_timer != NULL)) {
				lck_mtx_lock(&mppi->mppi_lock);
				if (gc && mppi->mppi_gc != NULL) {
					gc_act += mppi->mppi_gc(mppi);
				}
				if (t && mppi->mppi_timer != NULL) {
					t_act += mppi->mppi_timer(mppi);
				}
				lck_mtx_unlock(&mppi->mppi_lock);
			}
		}
		lck_mtx_unlock(&mp_lock);

		lck_mtx_lock_spin(&mp_timeout_lock);
	}

	/* lock was dropped above, so check first before overriding */
	if (!mp_garbage_collecting) {
		mp_garbage_collecting = (gc_act != 0);
	}
	if (!mp_ticking) {
		mp_ticking = (t_act != 0);
	}

	/* re-arm the timer if there's work to do */
	mp_timeout_run = FALSE;
	mp_sched_timeout();
	lck_mtx_unlock(&mp_timeout_lock);
}

static void
mp_sched_timeout(void)
{
	LCK_MTX_ASSERT(&mp_timeout_lock, LCK_MTX_ASSERT_OWNED);

	if (!mp_timeout_run && (mp_garbage_collecting || mp_ticking)) {
		lck_mtx_convert_spin(&mp_timeout_lock);
		mp_timeout_run = TRUE;
		timeout(mp_timeout, NULL, hz);
	}
}

void
mp_gc_sched(void)
{
	lck_mtx_lock_spin(&mp_timeout_lock);
	mp_garbage_collecting = TRUE;
	mp_sched_timeout();
	lck_mtx_unlock(&mp_timeout_lock);
}

void
mptcp_timer_sched(void)
{
	lck_mtx_lock_spin(&mp_timeout_lock);
	mp_ticking = TRUE;
	mp_sched_timeout();
	lck_mtx_unlock(&mp_timeout_lock);
}

void
mp_pcbinfo_attach(struct mppcbinfo *mppi)
{
	struct mppcbinfo *mppi0;

	lck_mtx_lock(&mp_lock);
	TAILQ_FOREACH(mppi0, &mppi_head, mppi_entry) {
		if (mppi0 == mppi) {
			panic("%s: mppi %p already in the list",
			    __func__, mppi);
			/* NOTREACHED */
		}
	}
	TAILQ_INSERT_TAIL(&mppi_head, mppi, mppi_entry);
	lck_mtx_unlock(&mp_lock);
}

int
mp_pcbinfo_detach(struct mppcbinfo *mppi)
{
	struct mppcbinfo *mppi0;
	int error = 0;

	lck_mtx_lock(&mp_lock);
	TAILQ_FOREACH(mppi0, &mppi_head, mppi_entry) {
		if (mppi0 == mppi) {
			break;
		}
	}
	if (mppi0 != NULL) {
		TAILQ_REMOVE(&mppi_head, mppi0, mppi_entry);
	} else {
		error = ENXIO;
	}
	lck_mtx_unlock(&mp_lock);

	return error;
}

int
mp_pcballoc(struct socket *so, struct mppcbinfo *mppi)
{
	struct mppcb *mpp = NULL;
	int error;

	VERIFY(mpsotomppcb(so) == NULL);

	mpp = mppi->mppi_alloc();
	lck_mtx_init(&mpp->mpp_lock, mppi->mppi_lock_grp, &mppi->mppi_lock_attr);
	mpp->mpp_pcbinfo = mppi;
	mpp->mpp_state = MPPCB_STATE_INUSE;
	mpp->mpp_socket = so;
	so->so_pcb = mpp;

	error = mptcp_session_create(mpp);
	if (error) {
		lck_mtx_destroy(&mpp->mpp_lock, mppi->mppi_lock_grp);
		mppi->mppi_free(mpp);
		return error;
	}

	lck_mtx_lock(&mppi->mppi_lock);
	mpp->mpp_flags |= MPP_ATTACHED;
	TAILQ_INSERT_TAIL(&mppi->mppi_pcbs, mpp, mpp_entry);
	mppi->mppi_count++;

	lck_mtx_unlock(&mppi->mppi_lock);

	return 0;
}

void
mp_pcbdetach(struct socket *mp_so)
{
	struct mppcb *mpp = mpsotomppcb(mp_so);

	mpp->mpp_state = MPPCB_STATE_DEAD;

	mp_gc_sched();
}

void
mptcp_pcbdispose(struct mppcb *mpp)
{
	struct mppcbinfo *mppi = mpp->mpp_pcbinfo;
	struct socket *mp_so = mpp->mpp_socket;

	VERIFY(mppi != NULL);

	LCK_MTX_ASSERT(&mppi->mppi_lock, LCK_MTX_ASSERT_OWNED);
	mpp_lock_assert_held(mpp);

	VERIFY(mpp->mpp_state == MPPCB_STATE_DEAD);
	VERIFY(mpp->mpp_flags & MPP_ATTACHED);

	mpp->mpp_flags &= ~MPP_ATTACHED;
	TAILQ_REMOVE(&mppi->mppi_pcbs, mpp, mpp_entry);
	VERIFY(mppi->mppi_count != 0);
	mppi->mppi_count--;

	if (mppi->mppi_count == 0) {
		if (mptcp_cellicon_refcount) {
			os_log_error(mptcp_log_handle, "%s: No more MPTCP-flows, but cell icon counter is %u\n",
			    __func__, mptcp_cellicon_refcount);
			mptcp_clear_cellicon();
			mptcp_cellicon_refcount = 0;
		}
	}

	VERIFY(mpp->mpp_inside == 0);
	mpp_unlock(mpp);

#if NECP
	necp_mppcb_dispose(mpp);
#endif /* NECP */

	sofreelastref(mp_so, 0);
	if (mp_so->so_rcv.sb_cc > 0 || mp_so->so_snd.sb_cc > 0) {
		/*
		 * selthreadclear() already called
		 * during sofreelastref() above.
		 */
		sbrelease(&mp_so->so_rcv);
		sbrelease(&mp_so->so_snd);
	}

	lck_mtx_destroy(&mpp->mpp_lock, mppi->mppi_lock_grp);

	VERIFY(mpp->mpp_socket != NULL);
	VERIFY(mpp->mpp_socket->so_usecount == 0);
	mpp->mpp_socket->so_pcb = NULL;
	mpp->mpp_socket = NULL;
	mppi->mppi_free(mpp);
}

static int
mp_getaddr_v4(struct socket *mp_so, struct sockaddr **nam, boolean_t peer)
{
	struct mptses *mpte = mpsotompte(mp_so);
	struct sockaddr_in *sin;

	/*
	 * Do the malloc first in case it blocks.
	 */
	sin = (struct sockaddr_in *)alloc_sockaddr(sizeof(*sin),
	    Z_WAITOK | Z_NOFAIL);

	sin->sin_family = AF_INET;

	if (!peer) {
		sin->sin_port = mpte->__mpte_src_v4.sin_port;
		sin->sin_addr = mpte->__mpte_src_v4.sin_addr;
	} else {
		sin->sin_port = mpte->__mpte_dst_v4.sin_port;
		sin->sin_addr = mpte->__mpte_dst_v4.sin_addr;
	}

	*nam = (struct sockaddr *)sin;
	return 0;
}

static int
mp_getaddr_v6(struct socket *mp_so, struct sockaddr **nam, boolean_t peer)
{
	struct mptses *mpte = mpsotompte(mp_so);
	struct in6_addr addr;
	in_port_t port;
	uint32_t ifscope;

	if (!peer) {
		port = mpte->__mpte_src_v6.sin6_port;
		addr = mpte->__mpte_src_v6.sin6_addr;
		ifscope = mpte->__mpte_src_v6.sin6_scope_id;
	} else {
		port = mpte->__mpte_dst_v6.sin6_port;
		addr = mpte->__mpte_dst_v6.sin6_addr;
		ifscope = mpte->__mpte_dst_v6.sin6_scope_id;
	}

	*nam = in6_sockaddr(port, &addr, ifscope);
	if (*nam == NULL) {
		return ENOBUFS;
	}

	return 0;
}

int
mp_getsockaddr(struct socket *mp_so, struct sockaddr **nam)
{
	struct mptses *mpte = mpsotompte(mp_so);

	if (mpte->mpte_src.sa_family == AF_INET || mpte->mpte_src.sa_family == 0) {
		return mp_getaddr_v4(mp_so, nam, false);
	} else if (mpte->mpte_src.sa_family == AF_INET6) {
		return mp_getaddr_v6(mp_so, nam, false);
	} else {
		return EINVAL;
	}
}

int
mp_getpeeraddr(struct socket *mp_so, struct sockaddr **nam)
{
	struct mptses *mpte = mpsotompte(mp_so);

	if (mpte->mpte_src.sa_family == AF_INET || mpte->mpte_src.sa_family == 0) {
		return mp_getaddr_v4(mp_so, nam, true);
	} else if (mpte->mpte_src.sa_family == AF_INET6) {
		return mp_getaddr_v6(mp_so, nam, true);
	} else {
		return EINVAL;
	}
}