/*      $NetBSD: l2cap_upper.c,v 1.19 2016/12/12 15:58:45 maya Exp $    */

/*-
 * Copyright (c) 2005 Iain Hibbert.
 * Copyright (c) 2006 Itronix Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. The name of Itronix Inc. may not be used to endorse
 *    or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``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 ITRONIX INC. 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: l2cap_upper.c,v 1.19 2016/12/12 15:58:45 maya Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>

#include <netbt/bluetooth.h>
#include <netbt/hci.h>
#include <netbt/l2cap.h>

/*******************************************************************************
 *
 *      L2CAP Channel - Upper Protocol API
 */

/*
 * l2cap_attach_pcb(handle, btproto, upper)
 *
 *      attach new l2cap_channel to handle, populate
 *      with reasonable defaults
 */
int
l2cap_attach_pcb(struct l2cap_channel **handle,
                const struct btproto *proto, void *upper)
{
        struct l2cap_channel *chan;

        KASSERT(handle != NULL);
        KASSERT(proto != NULL);
        KASSERT(upper != NULL);

        chan = malloc(sizeof(struct l2cap_channel), M_BLUETOOTH,
                        M_NOWAIT | M_ZERO);
        if (chan == NULL)
                return ENOMEM;

        chan->lc_proto = proto;
        chan->lc_upper = upper;

        chan->lc_state = L2CAP_CLOSED;

        chan->lc_lcid = L2CAP_NULL_CID;
        chan->lc_rcid = L2CAP_NULL_CID;

        chan->lc_laddr.bt_len = sizeof(struct sockaddr_bt);
        chan->lc_laddr.bt_family = AF_BLUETOOTH;
        chan->lc_laddr.bt_psm = L2CAP_PSM_ANY;

        chan->lc_raddr.bt_len = sizeof(struct sockaddr_bt);
        chan->lc_raddr.bt_family = AF_BLUETOOTH;
        chan->lc_raddr.bt_psm = L2CAP_PSM_ANY;

        chan->lc_imtu = L2CAP_MTU_DEFAULT;
        chan->lc_omtu = L2CAP_MTU_DEFAULT;
        chan->lc_flush = L2CAP_FLUSH_TIMO_DEFAULT;

        memcpy(&chan->lc_iqos, &l2cap_default_qos, sizeof(l2cap_qos_t));
        memcpy(&chan->lc_oqos, &l2cap_default_qos, sizeof(l2cap_qos_t));

        MBUFQ_INIT(&chan->lc_txq);

        *handle = chan;
        return 0;
}

/*
 * l2cap_bind_pcb(l2cap_channel, sockaddr)
 *
 *      set local address of channel
 */
int
l2cap_bind_pcb(struct l2cap_channel *chan, struct sockaddr_bt *addr)
{

        if (chan->lc_lcid != L2CAP_NULL_CID)
                return EINVAL;

        memcpy(&chan->lc_laddr, addr, sizeof(struct sockaddr_bt));
        return 0;
}

/*
 * l2cap_sockaddr_pcb(l2cap_channel, sockaddr)
 *
 *      get local address of channel
 */
int
l2cap_sockaddr_pcb(struct l2cap_channel *chan, struct sockaddr_bt *addr)
{

        memcpy(addr, &chan->lc_laddr, sizeof(struct sockaddr_bt));
        return 0;
}

/*
 * l2cap_connect_pcb(l2cap_channel, sockaddr)
 *
 *      Initiate a connection to destination. This corresponds to
 *      "Open Channel Request" in the L2CAP specification and will
 *      result in one of the following:
 *
 *              proto->connected(upper)
 *              proto->disconnected(upper, error)
 *
 *      and, optionally
 *              proto->connecting(upper)
 */
int
l2cap_connect_pcb(struct l2cap_channel *chan, struct sockaddr_bt *dest)
{
        struct hci_unit *unit;
        int err;

        memcpy(&chan->lc_raddr, dest, sizeof(struct sockaddr_bt));

        if (L2CAP_PSM_INVALID(chan->lc_raddr.bt_psm))
                return EINVAL;

        if (bdaddr_any(&chan->lc_raddr.bt_bdaddr))
                return EDESTADDRREQ;

        /* set local address if it needs setting */
        if (bdaddr_any(&chan->lc_laddr.bt_bdaddr)) {
                err = hci_route_lookup(&chan->lc_laddr.bt_bdaddr,
                                        &chan->lc_raddr.bt_bdaddr);
                if (err)
                        return err;
        }

        unit = hci_unit_lookup(&chan->lc_laddr.bt_bdaddr);
        if (unit == NULL)
                return EHOSTUNREACH;

        /* attach to active list */
        err = l2cap_cid_alloc(chan);
        if (err)
                return err;

        /* open link to remote device */
        chan->lc_link = hci_acl_open(unit, &chan->lc_raddr.bt_bdaddr);
        if (chan->lc_link == NULL)
                return EHOSTUNREACH;

        /* set the link mode */
        err = l2cap_setmode(chan);
        if (err == EINPROGRESS) {
                chan->lc_state = L2CAP_WAIT_SEND_CONNECT_REQ;
                (*chan->lc_proto->connecting)(chan->lc_upper);
                return 0;
        }
        if (err)
                goto fail;

        /*
         * We can queue a connect request now even though the link may
         * not yet be open; Our mode setting is assured, and the queue
         * will be started automatically at the right time.
         */
        chan->lc_state = L2CAP_WAIT_RECV_CONNECT_RSP;
        err = l2cap_send_connect_req(chan);
        if (err)
                goto fail;

        return 0;

fail:
        chan->lc_state = L2CAP_CLOSED;
        hci_acl_close(chan->lc_link, err);
        chan->lc_link = NULL;
        return err;
}

/*
 * l2cap_peeraddr_pcb(l2cap_channel, sockaddr)
 *
 *      get remote address of channel
 */
int
l2cap_peeraddr_pcb(struct l2cap_channel *chan, struct sockaddr_bt *addr)
{

        memcpy(addr, &chan->lc_raddr, sizeof(struct sockaddr_bt));
        return 0;
}

/*
 * l2cap_disconnect_pcb(l2cap_channel, linger)
 *
 *      Initiate L2CAP disconnection. This corresponds to
 *      "Close Channel Request" in the L2CAP specification
 *      and will result in a call to
 *
 *              proto->disconnected(upper, error)
 *
 *      when the disconnection is complete. If linger is set,
 *      the call will not be made until data has flushed from
 *      the queue.
 */
int
l2cap_disconnect_pcb(struct l2cap_channel *chan, int linger)
{
        int err = 0;

        if (chan->lc_state == L2CAP_CLOSED
            || chan->lc_state == L2CAP_WAIT_DISCONNECT)
                return EINVAL;

        chan->lc_flags |= L2CAP_SHUTDOWN;

        /*
         * no need to do anything unless the queue is empty or
         * we are not lingering..
         */
        if ((MBUFQ_FIRST(&chan->lc_txq) == NULL && chan->lc_pending == 0)
            || linger == 0) {
                chan->lc_state = L2CAP_WAIT_DISCONNECT;
                err = l2cap_send_disconnect_req(chan);
                if (err)
                        l2cap_close(chan, err);
        }
        return err;
}

/*
 * l2cap_detach_pcb(handle)
 *
 *      Detach l2cap channel from handle & close it down
 */
void
l2cap_detach_pcb(struct l2cap_channel **handle)
{
        struct l2cap_channel *chan;

        chan = *handle;
        *handle = NULL;

        if (chan->lc_state != L2CAP_CLOSED)
                l2cap_close(chan, 0);

        if (chan->lc_lcid != L2CAP_NULL_CID) {
                LIST_REMOVE(chan, lc_ncid);
                chan->lc_lcid = L2CAP_NULL_CID;
        }

        MBUFQ_DRAIN(&chan->lc_txq);

        /*
         * Could implement some kind of delayed expunge to make sure that the
         * CID is really dead before it becomes available for reuse?
         */

        free(chan, M_BLUETOOTH);
}

/*
 * l2cap_listen_pcb(l2cap_channel)
 *
 *      Use this channel as a listening post (until detached). This will
 *      result in calls to:
 *
 *              proto->newconn(upper, laddr, raddr)
 *
 *      for incoming connections matching the psm and local address of
 *      the channel. NULL address is permitted and matches any device.
 *      If L2CAP_PSM_ANY is bound the next higher unused value from the
 *      dynamic range (above 0x1001) will be selected.
 *
 *      The upper layer should create and return a new channel.
 *
 *      You cannot use this channel for anything else subsequent to this call
 */
int
l2cap_listen_pcb(struct l2cap_channel *chan)
{
        struct l2cap_channel *used, *prev = NULL;
        uint32_t psm;

        if (chan->lc_lcid != L2CAP_NULL_CID)
                return EINVAL;

        /*
         * This is simplistic but its not really worth spending a
         * lot of time looking for an unused PSM..
         */
        if (chan->lc_laddr.bt_psm == L2CAP_PSM_ANY) {
                psm = 0x1001;
                used = LIST_FIRST(&l2cap_listen_list);

                if (used != NULL && used->lc_laddr.bt_psm >= psm) {
                        psm = used->lc_laddr.bt_psm + 0x0002;
                        if ((psm & 0x0100) != 0)
                                psm += 0x0100;

                        if (psm > UINT16_MAX)
                                return EADDRNOTAVAIL;
                }

                chan->lc_laddr.bt_psm = psm;
        } else if (L2CAP_PSM_INVALID(chan->lc_laddr.bt_psm))
                return EINVAL;

        /*
         * This CID is irrelevant, as the channel is not stored on the active
         * list and the socket code does not allow operations on listening
         * sockets, but we set it so the detach code knows to LIST_REMOVE the
         * channel.
         */
        chan->lc_lcid = L2CAP_SIGNAL_CID;

        /*
         * The list of listening channels is stored in an order such that new
         * listeners dont usurp current listeners, but that specific listening
         * takes precedence over promiscuous, and the connect request code can
         * easily use the first matching entry.
         */
        LIST_FOREACH(used, &l2cap_listen_list, lc_ncid) {
                if (used->lc_laddr.bt_psm < chan->lc_laddr.bt_psm)
                        break;

                if (used->lc_laddr.bt_psm == chan->lc_laddr.bt_psm
                        && bdaddr_any(&used->lc_laddr.bt_bdaddr)
                        && !bdaddr_any(&chan->lc_laddr.bt_bdaddr))
                        break;

                prev = used;
        }

        if (prev == NULL)
                LIST_INSERT_HEAD(&l2cap_listen_list, chan, lc_ncid);
        else
                LIST_INSERT_AFTER(prev, chan, lc_ncid);

        return 0;
}

/*
 * l2cap_send_pcb(l2cap_channel, mbuf)
 *
 *      Output SDU on channel described by channel. This corresponds
 *      to "Send Data Request" in the L2CAP specification. The upper
 *      layer will be notified when SDU's have completed sending by a
 *      call to:
 *
 *              proto->complete(upper, n)
 *
 *      (currently n == 1)
 *
 *      Note: I'm not sure how this will work out, but I think that
 *      if outgoing Retransmission Mode or Flow Control Mode is
 *      negotiated then this call will not be made until the SDU has
 *      been acknowledged by the peer L2CAP entity. For 'Best Effort'
 *      it will be made when the packet has cleared the controller
 *      buffers.
 *
 *      We only support Basic mode so far, so encapsulate with a
 *      B-Frame header and start sending if we are not already
 */
int
l2cap_send_pcb(struct l2cap_channel *chan, struct mbuf *m)
{
        l2cap_hdr_t *hdr;
        int plen;

        if (chan->lc_state == L2CAP_CLOSED) {
                m_freem(m);
                return ENOTCONN;
        }

        plen = m->m_pkthdr.len;

        DPRINTFN(5, "send %d bytes on CID #%d (pending = %d)\n",
                plen, chan->lc_lcid, chan->lc_pending);

        /* Encapsulate with B-Frame */
        M_PREPEND(m, sizeof(l2cap_hdr_t), M_DONTWAIT);
        if (m == NULL)
                return ENOMEM;

        hdr = mtod(m, l2cap_hdr_t *);
        hdr->length = htole16(plen);
        hdr->dcid = htole16(chan->lc_rcid);

        /* Queue it on our list */
        MBUFQ_ENQUEUE(&chan->lc_txq, m);

        /* If we are not sending, then start doing so */
        if (chan->lc_pending == 0)
                return l2cap_start(chan);

        return 0;
}

/*
 * l2cap_setopt(l2cap_channel, sopt)
 *
 *      Apply configuration options to channel. This corresponds to
 *      "Configure Channel Request" in the L2CAP specification.
 *
 *      for SO_L2CAP_LM, the settings will take effect when the
 *      channel is established. If the channel is already open,
 *      a call to
 *              proto->linkmode(upper, new)
 *
 *      will be made when the change is complete.
 */
int
l2cap_setopt(struct l2cap_channel *chan, const struct sockopt *sopt)
{
        int mode, err = 0;
        uint16_t mtu;

        switch (sopt->sopt_name) {
        case SO_L2CAP_IMTU:     /* set Incoming MTU */
                err = sockopt_get(sopt, &mtu, sizeof(mtu));
                if (err)
                        break;

                if (mtu < L2CAP_MTU_MINIMUM)
                        err = EINVAL;
                else if (chan->lc_state == L2CAP_CLOSED)
                        chan->lc_imtu = mtu;
                else
                        err = EBUSY;

                break;

        case SO_L2CAP_LM:       /* set link mode */
                err = sockopt_getint(sopt, &mode);
                if (err)
                        break;

                mode &= (L2CAP_LM_SECURE | L2CAP_LM_ENCRYPT | L2CAP_LM_AUTH);

                if (mode & L2CAP_LM_SECURE)
                        mode |= L2CAP_LM_ENCRYPT;

                if (mode & L2CAP_LM_ENCRYPT)
                        mode |= L2CAP_LM_AUTH;

                chan->lc_mode = mode;

                if (chan->lc_state == L2CAP_OPEN)
                        err = l2cap_setmode(chan);

                break;

        case SO_L2CAP_OQOS:     /* set Outgoing QoS flow spec */
        case SO_L2CAP_FLUSH:    /* set Outgoing Flush Timeout */
        default:
                err = ENOPROTOOPT;
                break;
        }

        return err;
}

/*
 * l2cap_getopt(l2cap_channel, sopt)
 *
 *      Return configuration parameters.
 */
int
l2cap_getopt(struct l2cap_channel *chan, struct sockopt *sopt)
{

        switch (sopt->sopt_name) {
        case SO_L2CAP_IMTU:     /* get Incoming MTU */
                return sockopt_set(sopt, &chan->lc_imtu, sizeof(uint16_t));

        case SO_L2CAP_OMTU:     /* get Outgoing MTU */
                return sockopt_set(sopt, &chan->lc_omtu, sizeof(uint16_t));

        case SO_L2CAP_IQOS:     /* get Incoming QoS flow spec */
                return sockopt_set(sopt, &chan->lc_iqos, sizeof(l2cap_qos_t));

        case SO_L2CAP_OQOS:     /* get Outgoing QoS flow spec */
                return sockopt_set(sopt, &chan->lc_oqos, sizeof(l2cap_qos_t));

        case SO_L2CAP_FLUSH:    /* get Flush Timeout */
                return sockopt_set(sopt, &chan->lc_flush, sizeof(uint16_t));

        case SO_L2CAP_LM:       /* get link mode */
                return sockopt_setint(sopt, chan->lc_mode);

        default:
                break;
        }

        return ENOPROTOOPT;
}