text: /*	$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $	*/
  
  /*-
   * 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.
   */
  
  /* $FreeBSD: soc2013/dpl/head/usr.sbin/bluetooth/btpand/tap.c 187981 2009-01-30 22:23:21Z emax $ */
  
  #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>
  
  #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;
  }
  