/*-
 * 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.
 */

#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>

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;
        /* 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);
        /*
         * 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);

        sctp_pull_off_control_to_new_inp(inp, n_inp, stcb, SBL_WAIT);
        atomic_subtract_int(&stcb->asoc.refcnt, 1);

        return (0);
}