/*      $NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $   */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008 Iain Hibbert
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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>
__RCSID("$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/uio.h>

#include <net/if_tap.h>

#include <fcntl.h>
#include <libutil.h>
#include <paths.h>
#include <stdio.h>
#include <unistd.h>

#define L2CAP_SOCKET_CHECKED
#include "btpand.h"

static bool tap_send(channel_t *, packet_t *);
static bool tap_recv(packet_t *);

void
tap_init(void)
{
        channel_t *chan;
        struct ifreq ifr;
        int fd, s;
        char pidfile[PATH_MAX];

        fd = open(interface_name, O_RDWR);
        if (fd == -1) {
                log_err("Could not open \"%s\": %m", interface_name);
                exit(EXIT_FAILURE);
        }

        memset(&ifr, 0, sizeof(ifr));
        if (ioctl(fd, TAPGIFNAME, &ifr) == -1) {
                log_err("Could not get interface name: %m");
                exit(EXIT_FAILURE);
        }

        s = socket(AF_INET, SOCK_DGRAM, 0);
        if (s == -1) {
                log_err("Could not open PF_LINK socket: %m");
                exit(EXIT_FAILURE);
        }

        ifr.ifr_addr.sa_family = AF_LINK;
        ifr.ifr_addr.sa_len = ETHER_ADDR_LEN;
        b2eaddr(ifr.ifr_addr.sa_data, &local_bdaddr);

        if (ioctl(s, SIOCSIFLLADDR, &ifr) == -1) {
                log_err("Could not set %s physical address: %m", ifr.ifr_name);
                exit(EXIT_FAILURE);
        }

        if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) {
                log_err("Could not get interface flags: %m");
                exit(EXIT_FAILURE);
        }

        if ((ifr.ifr_flags & IFF_UP) == 0) {
                ifr.ifr_flags |= IFF_UP;

                if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1) {
                        log_err("Could not set IFF_UP: %m");
                        exit(EXIT_FAILURE);
                }
        }

        close(s);

        log_info("Using interface %s with addr %s", ifr.ifr_name,
                ether_ntoa((struct ether_addr *)&ifr.ifr_addr.sa_data));

        chan = channel_alloc();
        if (chan == NULL)
                exit(EXIT_FAILURE);

        chan->send = tap_send;
        chan->recv = tap_recv;
        chan->mru = ETHER_HDR_LEN + ETHER_MAX_LEN;
        memcpy(chan->raddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
        memcpy(chan->laddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
        chan->state = CHANNEL_OPEN;
        if (!channel_open(chan, fd))
                exit(EXIT_FAILURE);

        snprintf(pidfile, sizeof(pidfile), "%s/%s.pid",
                _PATH_VARRUN, ifr.ifr_name);
        chan->pfh = pidfile_open(pidfile, 0600, NULL);
        if (chan->pfh == NULL)
                log_err("can't create pidfile");
        else if (pidfile_write(chan->pfh) < 0) {
                log_err("can't write pidfile");
                pidfile_remove(chan->pfh);
                chan->pfh = NULL;
        }
}

static bool
tap_send(channel_t *chan, packet_t *pkt)
{
        struct iovec iov[4];
        ssize_t nw;

        iov[0].iov_base = pkt->dst;
        iov[0].iov_len = ETHER_ADDR_LEN;
        iov[1].iov_base = pkt->src;
        iov[1].iov_len = ETHER_ADDR_LEN;
        iov[2].iov_base = pkt->type;
        iov[2].iov_len = ETHER_TYPE_LEN;
        iov[3].iov_base = pkt->ptr;
        iov[3].iov_len = pkt->len;

        /* tap device write never fails */
        nw = writev(chan->fd, iov, __arraycount(iov));
        assert(nw > 0);

        return true;
}

static bool
tap_recv(packet_t *pkt)
{

        if (pkt->len < ETHER_HDR_LEN)
                return false;

        pkt->dst = pkt->ptr;
        packet_adj(pkt, ETHER_ADDR_LEN);
        pkt->src = pkt->ptr;
        packet_adj(pkt, ETHER_ADDR_LEN);
        pkt->type = pkt->ptr;
        packet_adj(pkt, ETHER_TYPE_LEN);

        return true;
}