/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * a) Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * b) 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.
 *
 * c) Neither the name of Cisco Systems, Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#ifdef __FreeBSD__
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/sys/netinet/sctp_peeloff.c 337708 2018-08-13 13:58:45Z tuexen $");
#endif

#include <netinet/sctp_os.h>
#include <netinet/sctp_pcb.h>
#include <netinet/sctputil.h>
#include <netinet/sctp_var.h>
#include <netinet/sctp_var.h>
#include <netinet/sctp_sysctl.h>
#include <netinet/sctp.h>
#include <netinet/sctp_uio.h>
#include <netinet/sctp_peeloff.h>
#include <netinet/sctputil.h>
#include <netinet/sctp_auth.h>

#if defined(__APPLE__)
#define APPLE_FILE_NO 5
#endif

int
sctp_can_peel_off(struct socket *head, sctp_assoc_t assoc_id)
{
	struct sctp_inpcb *inp;
	struct sctp_tcb *stcb;
	uint32_t state;

	if (head == NULL) {
		SCTP_LTRACE_ERR_RET(NULL, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, EBADF);
		return (EBADF);
	}
	inp = (struct sctp_inpcb *)head->so_pcb;
	if (inp == NULL) {
		SCTP_LTRACE_ERR_RET(NULL, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, EFAULT);
		return (EFAULT);
	}
	if ((inp->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
	    (inp->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) {
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, EOPNOTSUPP);
		return (EOPNOTSUPP);
	}
	stcb = sctp_findassociation_ep_asocid(inp, assoc_id, 1);
	if (stcb == NULL) {
		SCTP_LTRACE_ERR_RET(inp, stcb, NULL, SCTP_FROM_SCTP_PEELOFF, ENOENT);
		return (ENOENT);
	}
	state = SCTP_GET_STATE(stcb);
	if ((state == SCTP_STATE_EMPTY) ||
	    (state == SCTP_STATE_INUSE)) {
		SCTP_TCB_UNLOCK(stcb);
		SCTP_LTRACE_ERR_RET(inp, stcb, NULL, SCTP_FROM_SCTP_PEELOFF, ENOTCONN);
		return (ENOTCONN);
	}
	SCTP_TCB_UNLOCK(stcb);
	/* We are clear to peel this one off */
	return (0);
}

int
sctp_do_peeloff(struct socket *head, struct socket *so, sctp_assoc_t assoc_id)
{
	struct sctp_inpcb *inp, *n_inp;
	struct sctp_tcb *stcb;
	uint32_t state;

	inp = (struct sctp_inpcb *)head->so_pcb;
	if (inp == NULL) {
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, EFAULT);
		return (EFAULT);
	}
	stcb = sctp_findassociation_ep_asocid(inp, assoc_id, 1);
	if (stcb == NULL) {
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, ENOTCONN);
		return (ENOTCONN);
	}

	state = SCTP_GET_STATE(stcb);
	if ((state == SCTP_STATE_EMPTY) ||
	    (state == SCTP_STATE_INUSE)) {
		SCTP_TCB_UNLOCK(stcb);
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, ENOTCONN);
		return (ENOTCONN);
	}

	n_inp = (struct sctp_inpcb *)so->so_pcb;
	n_inp->sctp_flags = (SCTP_PCB_FLAGS_UDPTYPE |
	    SCTP_PCB_FLAGS_CONNECTED |
	    SCTP_PCB_FLAGS_IN_TCPPOOL |	/* Turn on Blocking IO */
	    (SCTP_PCB_COPY_FLAGS & inp->sctp_flags));
	n_inp->sctp_socket = so;
	n_inp->sctp_features = inp->sctp_features;
	n_inp->sctp_mobility_features = inp->sctp_mobility_features;
	n_inp->sctp_frag_point = inp->sctp_frag_point;
	n_inp->sctp_cmt_on_off = inp->sctp_cmt_on_off;
	n_inp->ecn_supported = inp->ecn_supported;
	n_inp->prsctp_supported = inp->prsctp_supported;
	n_inp->auth_supported = inp->auth_supported;
	n_inp->asconf_supported = inp->asconf_supported;
	n_inp->reconfig_supported = inp->reconfig_supported;
	n_inp->nrsack_supported = inp->nrsack_supported;
	n_inp->pktdrop_supported = inp->pktdrop_supported;
	n_inp->partial_delivery_point = inp->partial_delivery_point;
	n_inp->sctp_context = inp->sctp_context;
	n_inp->max_cwnd = inp->max_cwnd;
	n_inp->local_strreset_support = inp->local_strreset_support;
	n_inp->inp_starting_point_for_iterator = NULL;
	/* copy in the authentication parameters from the original endpoint */
	if (n_inp->sctp_ep.local_hmacs)
		sctp_free_hmaclist(n_inp->sctp_ep.local_hmacs);
	n_inp->sctp_ep.local_hmacs =
	    sctp_copy_hmaclist(inp->sctp_ep.local_hmacs);
	if (n_inp->sctp_ep.local_auth_chunks)
		sctp_free_chunklist(n_inp->sctp_ep.local_auth_chunks);
	n_inp->sctp_ep.local_auth_chunks =
	    sctp_copy_chunklist(inp->sctp_ep.local_auth_chunks);
	(void)sctp_copy_skeylist(&inp->sctp_ep.shared_keys,
	    &n_inp->sctp_ep.shared_keys);
#if defined(__Userspace__)
	n_inp->ulp_info = inp->ulp_info;
	n_inp->recv_callback = inp->recv_callback;
	n_inp->send_callback = inp->send_callback;
	n_inp->send_sb_threshold = inp->send_sb_threshold;
#endif
	/*
	 * Now we must move it from one hash table to another and get the
	 * stcb in the right place.
	 */
	sctp_move_pcb_and_assoc(inp, n_inp, stcb);
	atomic_add_int(&stcb->asoc.refcnt, 1);
	SCTP_TCB_UNLOCK(stcb);

#if defined(__FreeBSD__)
	sctp_pull_off_control_to_new_inp(inp, n_inp, stcb, SBL_WAIT);
#else
	sctp_pull_off_control_to_new_inp(inp, n_inp, stcb, M_WAITOK);
#endif
	atomic_subtract_int(&stcb->asoc.refcnt, 1);

	return (0);
}

#if defined(HAVE_SCTP_PEELOFF_SOCKOPT)
struct socket *
sctp_get_peeloff(struct socket *head, sctp_assoc_t assoc_id, int *error)
{
#if defined(__Userspace__)
    /* if __Userspace__ chooses to originally not support peeloff, put it here... */
#endif
#if defined(__Panda__)
	SCTP_LTRACE_ERR_RET(NULL, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, EINVAL);
	*error = EINVAL;
	return (NULL);
#else
	struct socket *newso;
	struct sctp_inpcb *inp, *n_inp;
	struct sctp_tcb *stcb;

	SCTPDBG(SCTP_DEBUG_PEEL1, "SCTP peel-off called\n");
	inp = (struct sctp_inpcb *)head->so_pcb;
	if (inp == NULL) {
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, EFAULT);
		*error = EFAULT;
		return (NULL);
	}
	stcb = sctp_findassociation_ep_asocid(inp, assoc_id, 1);
	if (stcb == NULL) {
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, ENOTCONN);
		*error = ENOTCONN;
		return (NULL);
	}
	atomic_add_int(&stcb->asoc.refcnt, 1);
	SCTP_TCB_UNLOCK(stcb);
#if defined(__FreeBSD__) && __FreeBSD_version >= 801000
	CURVNET_SET(head->so_vnet);
#endif
	newso = sonewconn(head, SS_ISCONNECTED
#if defined(__APPLE__)
	    , NULL
#elif defined(__Panda__)
	    /* place this socket in the assoc's vrf id */
	    , NULL, stcb->asoc.vrf_id
#endif
		);
#if defined(__FreeBSD__) && __FreeBSD_version >= 801000
	CURVNET_RESTORE();
#endif
	if (newso == NULL) {
		SCTPDBG(SCTP_DEBUG_PEEL1, "sctp_peeloff:sonewconn failed\n");
		SCTP_LTRACE_ERR_RET(NULL, stcb, NULL, SCTP_FROM_SCTP_PEELOFF, ENOMEM);
		*error = ENOMEM;
		atomic_subtract_int(&stcb->asoc.refcnt, 1);
		return (NULL);

	}
#if defined(__APPLE__)
	  else {
		SCTP_SOCKET_LOCK(newso, 1);
	}
#endif
	SCTP_TCB_LOCK(stcb);
	atomic_subtract_int(&stcb->asoc.refcnt, 1);
	n_inp = (struct sctp_inpcb *)newso->so_pcb;
	SOCK_LOCK(head);
	n_inp->sctp_flags = (SCTP_PCB_FLAGS_UDPTYPE |
	    SCTP_PCB_FLAGS_CONNECTED |
	    SCTP_PCB_FLAGS_IN_TCPPOOL |	/* Turn on Blocking IO */
	    (SCTP_PCB_COPY_FLAGS & inp->sctp_flags));
	n_inp->sctp_features = inp->sctp_features;
	n_inp->sctp_frag_point = inp->sctp_frag_point;
	n_inp->sctp_cmt_on_off = inp->sctp_cmt_on_off;
	n_inp->ecn_supported = inp->ecn_supported;
	n_inp->prsctp_supported = inp->prsctp_supported;
	n_inp->auth_supported = inp->auth_supported;
	n_inp->asconf_supported = inp->asconf_supported;
	n_inp->reconfig_supported = inp->reconfig_supported;
	n_inp->nrsack_supported = inp->nrsack_supported;
	n_inp->pktdrop_supported = inp->pktdrop_supported;
	n_inp->partial_delivery_point = inp->partial_delivery_point;
	n_inp->sctp_context = inp->sctp_context;
	n_inp->max_cwnd = inp->max_cwnd;
	n_inp->local_strreset_support = inp->local_strreset_support;
	n_inp->inp_starting_point_for_iterator = NULL;
#if defined(__Userspace__)
	n_inp->ulp_info = inp->ulp_info;
	n_inp->recv_callback = inp->recv_callback;
	n_inp->send_callback = inp->send_callback;
	n_inp->send_sb_threshold = inp->send_sb_threshold;
#endif

	/* copy in the authentication parameters from the original endpoint */
	if (n_inp->sctp_ep.local_hmacs)
		sctp_free_hmaclist(n_inp->sctp_ep.local_hmacs);
	n_inp->sctp_ep.local_hmacs =
	    sctp_copy_hmaclist(inp->sctp_ep.local_hmacs);
	if (n_inp->sctp_ep.local_auth_chunks)
		sctp_free_chunklist(n_inp->sctp_ep.local_auth_chunks);
	n_inp->sctp_ep.local_auth_chunks =
	    sctp_copy_chunklist(inp->sctp_ep.local_auth_chunks);
	(void)sctp_copy_skeylist(&inp->sctp_ep.shared_keys,
	    &n_inp->sctp_ep.shared_keys);

	n_inp->sctp_socket = newso;
	if (sctp_is_feature_on(inp, SCTP_PCB_FLAGS_AUTOCLOSE)) {
		sctp_feature_off(n_inp, SCTP_PCB_FLAGS_AUTOCLOSE);
		n_inp->sctp_ep.auto_close_time = 0;
		sctp_timer_stop(SCTP_TIMER_TYPE_AUTOCLOSE, n_inp, stcb, NULL,
				SCTP_FROM_SCTP_PEELOFF + SCTP_LOC_1);
	}
	/* Turn off any non-blocking semantic. */
	SOCK_LOCK(newso);
	SCTP_CLEAR_SO_NBIO(newso);
	newso->so_state |= SS_ISCONNECTED;
	SOCK_UNLOCK(newso);
	/* We remove it right away */

#if defined(__FreeBSD__) || defined(__APPLE__) || defined(__Windows__) || defined(__Userspace__)
#ifdef SCTP_LOCK_LOGGING
	if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LOCK_LOGGING_ENABLE) {
		sctp_log_lock(inp, (struct sctp_tcb *)NULL, SCTP_LOG_LOCK_SOCK);
	}
#endif
	TAILQ_REMOVE(&head->so_comp, newso, so_list);
	head->so_qlen--;
	SOCK_UNLOCK(head);
#else
	newso = TAILQ_FIRST(&head->so_q);
	if (soqremque(newso, 1) == 0) {
		SCTP_PRINTF("soremque failed, peeloff-fails (invarients would panic)\n");
		SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_PEELOFF, ENOTCONN);
		*error = ENOTCONN;
		return (NULL);

	}
#endif
	/*
	 * Now we must move it from one hash table to another and get the
	 * stcb in the right place.
	 */
	sctp_move_pcb_and_assoc(inp, n_inp, stcb);
	atomic_add_int(&stcb->asoc.refcnt, 1);
	SCTP_TCB_UNLOCK(stcb);
	/*
	 * And now the final hack. We move data in the pending side i.e.
	 * head to the new socket buffer. Let the GRUBBING begin :-0
	 */
#if defined(__FreeBSD__)
	sctp_pull_off_control_to_new_inp(inp, n_inp, stcb, SBL_WAIT);
#else
	sctp_pull_off_control_to_new_inp(inp, n_inp, stcb, M_WAITOK);
#endif
	atomic_subtract_int(&stcb->asoc.refcnt, 1);
	return (newso);
#endif
}
#endif
