text: /*
   * Copyright (c) 1993, 1994, 1995, 1996, 1998
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that: (1) source code distributions
   * retain the above copyright notice and this paragraph in its entirety, (2)
   * distributions including binary code include the above copyright notice and
   * this paragraph in its entirety in the documentation or other materials
   * provided with the distribution, and (3) all advertising materials mentioning
   * features or use of this software display the following acknowledgement:
   * ``This product includes software developed by the University of California,
   * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
   * the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   */
  
  #ifdef HAVE_CONFIG_H
  #include "config.h"
  #endif
  
  #include <sys/param.h>			/* optionally get BSD define */
  #ifdef HAVE_ZEROCOPY_BPF
  #include <sys/mman.h>
  #endif
  #include <sys/socket.h>
  #include <time.h>
  /*
   * <net/bpf.h> defines ioctls, but doesn't include <sys/ioccom.h>.
   *
   * We include <sys/ioctl.h> as it might be necessary to declare ioctl();
   * at least on *BSD and Mac OS X, it also defines various SIOC ioctls -
   * we could include <sys/sockio.h>, but if we're already including
   * <sys/ioctl.h>, which includes <sys/sockio.h> on those platforms,
   * there's not much point in doing so.
   *
   * If we have <sys/ioccom.h>, we include it as well, to handle systems
   * such as Solaris which don't arrange to include <sys/ioccom.h> if you
   * include <sys/ioctl.h>
   */
  #include <sys/ioctl.h>
  #ifdef HAVE_SYS_IOCCOM_H
  #include <sys/ioccom.h>
  #endif
  #include <sys/utsname.h>
  
  #if defined(__FreeBSD__) && defined(SIOCIFCREATE2)
  /*
   * Add support for capturing on FreeBSD usbusN interfaces.
   */
  static const char usbus_prefix[] = "usbus";
  #define USBUS_PREFIX_LEN	(sizeof(usbus_prefix) - 1)
  #include <dirent.h>
  #endif
  
  #ifdef HAVE_ZEROCOPY_BPF
  #include <machine/atomic.h>
  #endif
  
  #include <net/if.h>
  
  #ifdef _AIX
  
  /*
   * Make "pcap.h" not include "pcap/bpf.h"; we are going to include the
   * native OS version, as we need "struct bpf_config" from it.
   */
  #define PCAP_DONT_INCLUDE_PCAP_BPF_H
  
  #include <sys/types.h>
  
  /*
   * Prevent bpf.h from redefining the DLT_ values to their
   * IFT_ values, as we're going to return the standard libpcap
   * values, not IBM's non-standard IFT_ values.
   */
  #undef _AIX
  #include <net/bpf.h>
  #define _AIX
  
  #include <net/if_types.h>		/* for IFT_ values */
  #include <sys/sysconfig.h>
  #include <sys/device.h>
  #include <sys/cfgodm.h>
  #include <cf.h>
  
  #ifdef __64BIT__
  #define domakedev makedev64
  #define getmajor major64
  #define bpf_hdr bpf_hdr32
  #else /* __64BIT__ */
  #define domakedev makedev
  #define getmajor major
  #endif /* __64BIT__ */
  
  #define BPF_NAME "bpf"
  #define BPF_MINORS 4
  #define DRIVER_PATH "/usr/lib/drivers"
  #define BPF_NODE "/dev/bpf"
  static int bpfloadedflag = 0;
  static int odmlockid = 0;
  
  static int bpf_load(char *errbuf);
  
  #else /* _AIX */
  
  #include <net/bpf.h>
  
  #endif /* _AIX */
  
  #include <ctype.h>
  #include <fcntl.h>
  #include <errno.h>
  #include <netdb.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #ifdef HAVE_NET_IF_MEDIA_H
  # include <net/if_media.h>
  #endif
  
  #include "pcap-int.h"
  
  #ifdef HAVE_OS_PROTO_H
  #include "os-proto.h"
  #endif
  
  /*
   * Later versions of NetBSD stick padding in front of FDDI frames
   * to align the IP header on a 4-byte boundary.
   */
  #if defined(__NetBSD__) && __NetBSD_Version__ > 106000000
  #define       PCAP_FDDIPAD 3
  #endif
  
  /*
   * Private data for capturing on BPF devices.
   */
  struct pcap_bpf {
  #ifdef HAVE_ZEROCOPY_BPF
  	/*
  	 * Zero-copy read buffer -- for zero-copy BPF.  'buffer' above will
  	 * alternative between these two actual mmap'd buffers as required.
  	 * As there is a header on the front size of the mmap'd buffer, only
  	 * some of the buffer is exposed to libpcap as a whole via bufsize;
  	 * zbufsize is the true size.  zbuffer tracks the current zbuf
  	 * assocated with buffer so that it can be used to decide which the
  	 * next buffer to read will be.
  	 */
  	u_char *zbuf1, *zbuf2, *zbuffer;
  	u_int zbufsize;
  	u_int zerocopy;
  	u_int interrupted;
  	struct timespec firstsel;
  	/*
  	 * If there's currently a buffer being actively processed, then it is
  	 * referenced here; 'buffer' is also pointed at it, but offset by the
  	 * size of the header.
  	 */
  	struct bpf_zbuf_header *bzh;
  	int nonblock;		/* true if in nonblocking mode */
  #endif /* HAVE_ZEROCOPY_BPF */
  
  	char *device;		/* device name */
  	int filtering_in_kernel; /* using kernel filter */
  	int must_do_on_close;	/* stuff we must do when we close */
  };
  
  /*
   * Stuff to do when we close.
   */
  #define MUST_CLEAR_RFMON	0x00000001	/* clear rfmon (monitor) mode */
  #define MUST_DESTROY_USBUS	0x00000002	/* destroy usbusN interface */
  
  #ifdef BIOCGDLTLIST
  # if (defined(HAVE_NET_IF_MEDIA_H) && defined(IFM_IEEE80211)) && !defined(__APPLE__)
  #define HAVE_BSD_IEEE80211
  
  /*
   * The ifm_ulist member of a struct ifmediareq is an int * on most systems,
   * but it's a uint64_t on newer versions of OpenBSD.
   *
   * We check this by checking whether IFM_GMASK is defined and > 2^32-1.
   */
  #  if defined(IFM_GMASK) && IFM_GMASK > 0xFFFFFFFF
  #    define IFM_ULIST_TYPE	uint64_t
  #  else
  #    define IFM_ULIST_TYPE	int
  #  endif
  # endif
  
  # if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)
  static int find_802_11(struct bpf_dltlist *);
  
  #  ifdef HAVE_BSD_IEEE80211
  static int monitor_mode(pcap_t *, int);
  #  endif
  
  #  if defined(__APPLE__)
  static void remove_en(pcap_t *);
  static void remove_802_11(pcap_t *);
  #  endif
  
  # endif /* defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) */
  
  #endif /* BIOCGDLTLIST */
  
  #if defined(sun) && defined(LIFNAMSIZ) && defined(lifr_zoneid)
  #include <zone.h>
  #endif
  
  /*
   * We include the OS's <net/bpf.h>, not our "pcap/bpf.h", so we probably
   * don't get DLT_DOCSIS defined.
   */
  #ifndef DLT_DOCSIS
  #define DLT_DOCSIS	143
  #endif
  
  /*
   * On OS X, we don't even get any of the 802.11-plus-radio-header DLT_'s
   * defined, even though some of them are used by various Airport drivers.
   */
  #ifndef DLT_PRISM_HEADER
  #define DLT_PRISM_HEADER	119
  #endif
  #ifndef DLT_AIRONET_HEADER
  #define DLT_AIRONET_HEADER	120
  #endif
  #ifndef DLT_IEEE802_11_RADIO
  #define DLT_IEEE802_11_RADIO	127
  #endif
  #ifndef DLT_IEEE802_11_RADIO_AVS
  #define DLT_IEEE802_11_RADIO_AVS 163
  #endif
  
  static int pcap_can_set_rfmon_bpf(pcap_t *p);
  static int pcap_activate_bpf(pcap_t *p);
  static int pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp);
  static int pcap_setdirection_bpf(pcap_t *, pcap_direction_t);
  static int pcap_set_datalink_bpf(pcap_t *p, int dlt);
  
  /*
   * For zerocopy bpf, the setnonblock/getnonblock routines need to modify
   * pb->nonblock so we don't call select(2) if the pcap handle is in non-
   * blocking mode.
   */
  static int
  pcap_getnonblock_bpf(pcap_t *p, char *errbuf)
  {
  #ifdef HAVE_ZEROCOPY_BPF
  	struct pcap_bpf *pb = p->priv;
  
  	if (pb->zerocopy)
  		return (pb->nonblock);
  #endif
  	return (pcap_getnonblock_fd(p, errbuf));
  }
  
  static int
  pcap_setnonblock_bpf(pcap_t *p, int nonblock, char *errbuf)
  {
  #ifdef HAVE_ZEROCOPY_BPF
  	struct pcap_bpf *pb = p->priv;
  
  	if (pb->zerocopy) {
  		pb->nonblock = nonblock;
  		return (0);
  	}
  #endif
  	return (pcap_setnonblock_fd(p, nonblock, errbuf));
  }
  
  #ifdef HAVE_ZEROCOPY_BPF
  /*
   * Zero-copy BPF buffer routines to check for and acknowledge BPF data in
   * shared memory buffers.
   *
   * pcap_next_zbuf_shm(): Check for a newly available shared memory buffer,
   * and set up p->buffer and cc to reflect one if available.  Notice that if
   * there was no prior buffer, we select zbuf1 as this will be the first
   * buffer filled for a fresh BPF session.
   */
  static int
  pcap_next_zbuf_shm(pcap_t *p, int *cc)
  {
  	struct pcap_bpf *pb = p->priv;
  	struct bpf_zbuf_header *bzh;
  
  	if (pb->zbuffer == pb->zbuf2 || pb->zbuffer == NULL) {
  		bzh = (struct bpf_zbuf_header *)pb->zbuf1;
  		if (bzh->bzh_user_gen !=
  		    atomic_load_acq_int(&bzh->bzh_kernel_gen)) {
  			pb->bzh = bzh;
  			pb->zbuffer = (u_char *)pb->zbuf1;
  			p->buffer = pb->zbuffer + sizeof(*bzh);
  			*cc = bzh->bzh_kernel_len;
  			return (1);
  		}
  	} else if (pb->zbuffer == pb->zbuf1) {
  		bzh = (struct bpf_zbuf_header *)pb->zbuf2;
  		if (bzh->bzh_user_gen !=
  		    atomic_load_acq_int(&bzh->bzh_kernel_gen)) {
  			pb->bzh = bzh;
  			pb->zbuffer = (u_char *)pb->zbuf2;
    			p->buffer = pb->zbuffer + sizeof(*bzh);
  			*cc = bzh->bzh_kernel_len;
  			return (1);
  		}
  	}
  	*cc = 0;
  	return (0);
  }
  
  /*
   * pcap_next_zbuf() -- Similar to pcap_next_zbuf_shm(), except wait using
   * select() for data or a timeout, and possibly force rotation of the buffer
   * in the event we time out or are in immediate mode.  Invoke the shared
   * memory check before doing system calls in order to avoid doing avoidable
   * work.
   */
  static int
  pcap_next_zbuf(pcap_t *p, int *cc)
  {
  	struct pcap_bpf *pb = p->priv;
  	struct bpf_zbuf bz;
  	struct timeval tv;
  	struct timespec cur;
  	fd_set r_set;
  	int data, r;
  	int expire, tmout;
  
  #define TSTOMILLI(ts) (((ts)->tv_sec * 1000) + ((ts)->tv_nsec / 1000000))
  	/*
  	 * Start out by seeing whether anything is waiting by checking the
  	 * next shared memory buffer for data.
  	 */
  	data = pcap_next_zbuf_shm(p, cc);
  	if (data)
  		return (data);
  	/*
  	 * If a previous sleep was interrupted due to signal delivery, make
  	 * sure that the timeout gets adjusted accordingly.  This requires
  	 * that we analyze when the timeout should be been expired, and
  	 * subtract the current time from that.  If after this operation,
  	 * our timeout is less then or equal to zero, handle it like a
  	 * regular timeout.
  	 */
  	tmout = p->opt.timeout;
  	if (tmout)
  		(void) clock_gettime(CLOCK_MONOTONIC, &cur);
  	if (pb->interrupted && p->opt.timeout) {
  		expire = TSTOMILLI(&pb->firstsel) + p->opt.timeout;
  		tmout = expire - TSTOMILLI(&cur);
  #undef TSTOMILLI
  		if (tmout <= 0) {
  			pb->interrupted = 0;
  			data = pcap_next_zbuf_shm(p, cc);
  			if (data)
  				return (data);
  			if (ioctl(p->fd, BIOCROTZBUF, &bz) < 0) {
  				(void) pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "BIOCROTZBUF: %s", strerror(errno));
  				return (PCAP_ERROR);
  			}
  			return (pcap_next_zbuf_shm(p, cc));
  		}
  	}
  	/*
  	 * No data in the buffer, so must use select() to wait for data or
  	 * the next timeout.  Note that we only call select if the handle
  	 * is in blocking mode.
  	 */
  	if (!pb->nonblock) {
  		FD_ZERO(&r_set);
  		FD_SET(p->fd, &r_set);
  		if (tmout != 0) {
  			tv.tv_sec = tmout / 1000;
  			tv.tv_usec = (tmout * 1000) % 1000000;
  		}
  		r = select(p->fd + 1, &r_set, NULL, NULL,
  		    p->opt.timeout != 0 ? &tv : NULL);
  		if (r < 0 && errno == EINTR) {
  			if (!pb->interrupted && p->opt.timeout) {
  				pb->interrupted = 1;
  				pb->firstsel = cur;
  			}
  			return (0);
  		} else if (r < 0) {
  			(void) pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "select: %s", strerror(errno));
  			return (PCAP_ERROR);
  		}
  	}
  	pb->interrupted = 0;
  	/*
  	 * Check again for data, which may exist now that we've either been
  	 * woken up as a result of data or timed out.  Try the "there's data"
  	 * case first since it doesn't require a system call.
  	 */
  	data = pcap_next_zbuf_shm(p, cc);
  	if (data)
  		return (data);
  	/*
  	 * Try forcing a buffer rotation to dislodge timed out or immediate
  	 * data.
  	 */
  	if (ioctl(p->fd, BIOCROTZBUF, &bz) < 0) {
  		(void) pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  		    "BIOCROTZBUF: %s", strerror(errno));
  		return (PCAP_ERROR);
  	}
  	return (pcap_next_zbuf_shm(p, cc));
  }
  
  /*
   * Notify kernel that we are done with the buffer.  We don't reset zbuffer so
   * that we know which buffer to use next time around.
   */
  static int
  pcap_ack_zbuf(pcap_t *p)
  {
  	struct pcap_bpf *pb = p->priv;
  
  	atomic_store_rel_int(&pb->bzh->bzh_user_gen,
  	    pb->bzh->bzh_kernel_gen);
  	pb->bzh = NULL;
  	p->buffer = NULL;
  	return (0);
  }
  #endif /* HAVE_ZEROCOPY_BPF */
  
  pcap_t *
  pcap_create_interface(const char *device _U_, char *ebuf)
  {
  	pcap_t *p;
  
  	p = pcap_create_common(ebuf, sizeof (struct pcap_bpf));
  	if (p == NULL)
  		return (NULL);
  
  	p->activate_op = pcap_activate_bpf;
  	p->can_set_rfmon_op = pcap_can_set_rfmon_bpf;
  #ifdef BIOCSTSTAMP
  	/*
  	 * We claim that we support microsecond and nanosecond time
  	 * stamps.
  	 */
  	p->tstamp_precision_count = 2;
  	p->tstamp_precision_list = malloc(2 * sizeof(u_int));
  	if (p->tstamp_precision_list == NULL) {
  		snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
  		    pcap_strerror(errno));
  		free(p);
  		return (NULL);
  	}
  	p->tstamp_precision_list[0] = PCAP_TSTAMP_PRECISION_MICRO;
  	p->tstamp_precision_list[1] = PCAP_TSTAMP_PRECISION_NANO;
  #endif /* BIOCSTSTAMP */
  	return (p);
  }
  
  /*
   * On success, returns a file descriptor for a BPF device.
   * On failure, returns a PCAP_ERROR_ value, and sets p->errbuf.
   */
  static int
  bpf_open(char *errbuf)
  {
  	int fd;
  #ifdef HAVE_CLONING_BPF
  	static const char device[] = "/dev/bpf";
  #else
  	int n = 0;
  	char device[sizeof "/dev/bpf0000000000"];
  #endif
  
  #ifdef _AIX
  	/*
  	 * Load the bpf driver, if it isn't already loaded,
  	 * and create the BPF device entries, if they don't
  	 * already exist.
  	 */
  	if (bpf_load(errbuf) == PCAP_ERROR)
  		return (PCAP_ERROR);
  #endif
  
  #ifdef HAVE_CLONING_BPF
  	if ((fd = open(device, O_RDWR)) == -1 &&
  	    (errno != EACCES || (fd = open(device, O_RDONLY)) == -1)) {
  		if (errno == EACCES)
  			fd = PCAP_ERROR_PERM_DENIED;
  		else
  			fd = PCAP_ERROR;
  		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  		  "(cannot open device) %s: %s", device, pcap_strerror(errno));
  	}
  #else
  	/*
  	 * Go through all the minors and find one that isn't in use.
  	 */
  	do {
  		(void)pcap_snprintf(device, sizeof(device), "/dev/bpf%d", n++);
  		/*
  		 * Initially try a read/write open (to allow the inject
  		 * method to work).  If that fails due to permission
  		 * issues, fall back to read-only.  This allows a
  		 * non-root user to be granted specific access to pcap
  		 * capabilities via file permissions.
  		 *
  		 * XXX - we should have an API that has a flag that
  		 * controls whether to open read-only or read-write,
  		 * so that denial of permission to send (or inability
  		 * to send, if sending packets isn't supported on
  		 * the device in question) can be indicated at open
  		 * time.
  		 */
  		fd = open(device, O_RDWR);
  		if (fd == -1 && errno == EACCES)
  			fd = open(device, O_RDONLY);
  	} while (fd < 0 && errno == EBUSY);
  
  	/*
  	 * XXX better message for all minors used
  	 */
  	if (fd < 0) {
  		switch (errno) {
  
  		case ENOENT:
  			fd = PCAP_ERROR;
  			if (n == 1) {
  				/*
  				 * /dev/bpf0 doesn't exist, which
  				 * means we probably have no BPF
  				 * devices.
  				 */
  				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  				    "(there are no BPF devices)");
  			} else {
  				/*
  				 * We got EBUSY on at least one
  				 * BPF device, so we have BPF
  				 * devices, but all the ones
  				 * that exist are busy.
  				 */
  				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  				    "(all BPF devices are busy)");
  			}
  			break;
  
  		case EACCES:
  			/*
  			 * Got EACCES on the last device we tried,
  			 * and EBUSY on all devices before that,
  			 * if any.
  			 */
  			fd = PCAP_ERROR_PERM_DENIED;
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "(cannot open BPF device) %s: %s", device,
  			    pcap_strerror(errno));
  			break;
  
  		default:
  			/*
  			 * Some other problem.
  			 */
  			fd = PCAP_ERROR;
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "(cannot open BPF device) %s: %s", device,
  			    pcap_strerror(errno));
  			break;
  		}
  	}
  #endif
  
  	return (fd);
  }
  
  /*
   * Open and bind to a device; used if we're not actually going to use
   * the device, but are just testing whether it can be opened, or opening
   * it to get information about it.
   *
   * Returns an error code on failure (always negative), and an FD for
   * the now-bound BPF device on success (always non-negative).
   */
  static int
  bpf_open_and_bind(const char *name, char *errbuf)
  {
  	int fd;
  	struct ifreq ifr;
  
  	/*
  	 * First, open a BPF device.
  	 */
  	fd = bpf_open(errbuf);
  	if (fd < 0)
  		return (fd);	/* fd is the appropriate error code */
  
  	/*
  	 * Now bind to the device.
  	 */
  	(void)strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
  	if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
  		switch (errno) {
  
  		case ENXIO:
  			/*
  			 * There's no such device.
  			 */
  			close(fd);
  			return (PCAP_ERROR_NO_SUCH_DEVICE);
  
  		case ENETDOWN:
  			/*
  			 * Return a "network down" indication, so that
  			 * the application can report that rather than
  			 * saying we had a mysterious failure and
  			 * suggest that they report a problem to the
  			 * libpcap developers.
  			 */
  			close(fd);
  			return (PCAP_ERROR_IFACE_NOT_UP);
  
  		default:
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "BIOCSETIF: %s: %s", name, pcap_strerror(errno));
  			close(fd);
  			return (PCAP_ERROR);
  		}
  	}
  
  	/*
  	 * Success.
  	 */
  	return (fd);
  }
  
  #ifdef BIOCGDLTLIST
  static int
  get_dlt_list(int fd, int v, struct bpf_dltlist *bdlp, char *ebuf)
  {
  	memset(bdlp, 0, sizeof(*bdlp));
  	if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) == 0) {
  		u_int i;
  		int is_ethernet;
  
  		bdlp->bfl_list = (u_int *) malloc(sizeof(u_int) * (bdlp->bfl_len + 1));
  		if (bdlp->bfl_list == NULL) {
  			(void)pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
  			    pcap_strerror(errno));
  			return (PCAP_ERROR);
  		}
  
  		if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) < 0) {
  			(void)pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
  			    "BIOCGDLTLIST: %s", pcap_strerror(errno));
  			free(bdlp->bfl_list);
  			return (PCAP_ERROR);
  		}
  
  		/*
  		 * OK, for real Ethernet devices, add DLT_DOCSIS to the
  		 * list, so that an application can let you choose it,
  		 * in case you're capturing DOCSIS traffic that a Cisco
  		 * Cable Modem Termination System is putting out onto
  		 * an Ethernet (it doesn't put an Ethernet header onto
  		 * the wire, it puts raw DOCSIS frames out on the wire
  		 * inside the low-level Ethernet framing).
  		 *
  		 * A "real Ethernet device" is defined here as a device
  		 * that has a link-layer type of DLT_EN10MB and that has
  		 * no alternate link-layer types; that's done to exclude
  		 * 802.11 interfaces (which might or might not be the
  		 * right thing to do, but I suspect it is - Ethernet <->
  		 * 802.11 bridges would probably badly mishandle frames
  		 * that don't have Ethernet headers).
  		 *
  		 * On Solaris with BPF, Ethernet devices also offer
  		 * DLT_IPNET, so we, if DLT_IPNET is defined, we don't
  		 * treat it as an indication that the device isn't an
  		 * Ethernet.
  		 */
  		if (v == DLT_EN10MB) {
  			is_ethernet = 1;
  			for (i = 0; i < bdlp->bfl_len; i++) {
  				if (bdlp->bfl_list[i] != DLT_EN10MB
  #ifdef DLT_IPNET
  				    && bdlp->bfl_list[i] != DLT_IPNET
  #endif
  				    ) {
  					is_ethernet = 0;
  					break;
  				}
  			}
  			if (is_ethernet) {
  				/*
  				 * We reserved one more slot at the end of
  				 * the list.
  				 */
  				bdlp->bfl_list[bdlp->bfl_len] = DLT_DOCSIS;
  				bdlp->bfl_len++;
  			}
  		}
  	} else {
  		/*
  		 * EINVAL just means "we don't support this ioctl on
  		 * this device"; don't treat it as an error.
  		 */
  		if (errno != EINVAL) {
  			(void)pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
  			    "BIOCGDLTLIST: %s", pcap_strerror(errno));
  			return (PCAP_ERROR);
  		}
  	}
  	return (0);
  }
  #endif
  
  static int
  pcap_can_set_rfmon_bpf(pcap_t *p)
  {
  #if defined(__APPLE__)
  	struct utsname osinfo;
  	struct ifreq ifr;
  	int fd;
  #ifdef BIOCGDLTLIST
  	struct bpf_dltlist bdl;
  #endif
  
  	/*
  	 * The joys of monitor mode on OS X.
  	 *
  	 * Prior to 10.4, it's not supported at all.
  	 *
  	 * In 10.4, if adapter enN supports monitor mode, there's a
  	 * wltN adapter corresponding to it; you open it, instead of
  	 * enN, to get monitor mode.  You get whatever link-layer
  	 * headers it supplies.
  	 *
  	 * In 10.5, and, we assume, later releases, if adapter enN
  	 * supports monitor mode, it offers, among its selectable
  	 * DLT_ values, values that let you get the 802.11 header;
  	 * selecting one of those values puts the adapter into monitor
  	 * mode (i.e., you can't get 802.11 headers except in monitor
  	 * mode, and you can't get Ethernet headers in monitor mode).
  	 */
  	if (uname(&osinfo) == -1) {
  		/*
  		 * Can't get the OS version; just say "no".
  		 */
  		return (0);
  	}
  	/*
  	 * We assume osinfo.sysname is "Darwin", because
  	 * __APPLE__ is defined.  We just check the version.
  	 */
  	if (osinfo.release[0] < '8' && osinfo.release[1] == '.') {
  		/*
  		 * 10.3 (Darwin 7.x) or earlier.
  		 * Monitor mode not supported.
  		 */
  		return (0);
  	}
  	if (osinfo.release[0] == '8' && osinfo.release[1] == '.') {
  		/*
  		 * 10.4 (Darwin 8.x).  s/en/wlt/, and check
  		 * whether the device exists.
  		 */
  		if (strncmp(p->opt.device, "en", 2) != 0) {
  			/*
  			 * Not an enN device; no monitor mode.
  			 */
  			return (0);
  		}
  		fd = socket(AF_INET, SOCK_DGRAM, 0);
  		if (fd == -1) {
  			(void)pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "socket: %s", pcap_strerror(errno));
  			return (PCAP_ERROR);
  		}
  		strlcpy(ifr.ifr_name, "wlt", sizeof(ifr.ifr_name));
  		strlcat(ifr.ifr_name, p->opt.device + 2, sizeof(ifr.ifr_name));
  		if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
  			/*
  			 * No such device?
  			 */
  			close(fd);
  			return (0);
  		}
  		close(fd);
  		return (1);
  	}
  
  #ifdef BIOCGDLTLIST
  	/*
  	 * Everything else is 10.5 or later; for those,
  	 * we just open the enN device, and check whether
  	 * we have any 802.11 devices.
  	 *
  	 * First, open a BPF device.
  	 */
  	fd = bpf_open(p->errbuf);
  	if (fd < 0)
  		return (fd);	/* fd is the appropriate error code */
  
  	/*
  	 * Now bind to the device.
  	 */
  	(void)strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
  	if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
  		switch (errno) {
  
  		case ENXIO:
  			/*
  			 * There's no such device.
  			 */
  			close(fd);
  			return (PCAP_ERROR_NO_SUCH_DEVICE);
  
  		case ENETDOWN:
  			/*
  			 * Return a "network down" indication, so that
  			 * the application can report that rather than
  			 * saying we had a mysterious failure and
  			 * suggest that they report a problem to the
  			 * libpcap developers.
  			 */
  			close(fd);
  			return (PCAP_ERROR_IFACE_NOT_UP);
  
  		default:
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "BIOCSETIF: %s: %s",
  			    p->opt.device, pcap_strerror(errno));
  			close(fd);
  			return (PCAP_ERROR);
  		}
  	}
  
  	/*
  	 * We know the default link type -- now determine all the DLTs
  	 * this interface supports.  If this fails with EINVAL, it's
  	 * not fatal; we just don't get to use the feature later.
  	 * (We don't care about DLT_DOCSIS, so we pass DLT_NULL
  	 * as the default DLT for this adapter.)
  	 */
  	if (get_dlt_list(fd, DLT_NULL, &bdl, p->errbuf) == PCAP_ERROR) {
  		close(fd);
  		return (PCAP_ERROR);
  	}
  	if (find_802_11(&bdl) != -1) {
  		/*
  		 * We have an 802.11 DLT, so we can set monitor mode.
  		 */
  		free(bdl.bfl_list);
  		close(fd);
  		return (1);
  	}
  	free(bdl.bfl_list);
  	close(fd);
  #endif /* BIOCGDLTLIST */
  	return (0);
  #elif defined(HAVE_BSD_IEEE80211)
  	int ret;
  
  	ret = monitor_mode(p, 0);
  	if (ret == PCAP_ERROR_RFMON_NOTSUP)
  		return (0);	/* not an error, just a "can't do" */
  	if (ret == 0)
  		return (1);	/* success */
  	return (ret);
  #else
  	return (0);
  #endif
  }
  
  static int
  pcap_stats_bpf(pcap_t *p, struct pcap_stat *ps)
  {
  	struct bpf_stat s;
  
  	/*
  	 * "ps_recv" counts packets handed to the filter, not packets
  	 * that passed the filter.  This includes packets later dropped
  	 * because we ran out of buffer space.
  	 *
  	 * "ps_drop" counts packets dropped inside the BPF device
  	 * because we ran out of buffer space.  It doesn't count
  	 * packets dropped by the interface driver.  It counts
  	 * only packets that passed the filter.
  	 *
  	 * Both statistics include packets not yet read from the kernel
  	 * by libpcap, and thus not yet seen by the application.
  	 */
  	if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s",
  		    pcap_strerror(errno));
  		return (PCAP_ERROR);
  	}
  
  	ps->ps_recv = s.bs_recv;
  	ps->ps_drop = s.bs_drop;
  	ps->ps_ifdrop = 0;
  	return (0);
  }
  
  static int
  pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  {
  	struct pcap_bpf *pb = p->priv;
  	int cc;
  	int n = 0;
  	register u_char *bp, *ep;
  	u_char *datap;
  #ifdef PCAP_FDDIPAD
  	register u_int pad;
  #endif
  #ifdef HAVE_ZEROCOPY_BPF
  	int i;
  #endif
  
   again:
  	/*
  	 * Has "pcap_breakloop()" been called?
  	 */
  	if (p->break_loop) {
  		/*
  		 * Yes - clear the flag that indicates that it
  		 * has, and return PCAP_ERROR_BREAK to indicate
  		 * that we were told to break out of the loop.
  		 */
  		p->break_loop = 0;
  		return (PCAP_ERROR_BREAK);
  	}
  	cc = p->cc;
  	if (p->cc == 0) {
  		/*
  		 * When reading without zero-copy from a file descriptor, we
  		 * use a single buffer and return a length of data in the
  		 * buffer.  With zero-copy, we update the p->buffer pointer
  		 * to point at whatever underlying buffer contains the next
  		 * data and update cc to reflect the data found in the
  		 * buffer.
  		 */
  #ifdef HAVE_ZEROCOPY_BPF
  		if (pb->zerocopy) {
  			if (p->buffer != NULL)
  				pcap_ack_zbuf(p);
  			i = pcap_next_zbuf(p, &cc);
  			if (i == 0)
  				goto again;
  			if (i < 0)
  				return (PCAP_ERROR);
  		} else
  #endif
  		{
  			cc = read(p->fd, p->buffer, p->bufsize);
  		}
  		if (cc < 0) {
  			/* Don't choke when we get ptraced */
  			switch (errno) {
  
  			case EINTR:
  				goto again;
  
  #ifdef _AIX
  			case EFAULT:
  				/*
  				 * Sigh.  More AIX wonderfulness.
  				 *
  				 * For some unknown reason the uiomove()
  				 * operation in the bpf kernel extension
  				 * used to copy the buffer into user
  				 * space sometimes returns EFAULT. I have
  				 * no idea why this is the case given that
  				 * a kernel debugger shows the user buffer
  				 * is correct. This problem appears to
  				 * be mostly mitigated by the memset of
  				 * the buffer before it is first used.
  				 * Very strange.... Shaun Clowes
  				 *
  				 * In any case this means that we shouldn't
  				 * treat EFAULT as a fatal error; as we
  				 * don't have an API for returning
  				 * a "some packets were dropped since
  				 * the last packet you saw" indication,
  				 * we just ignore EFAULT and keep reading.
  				 */
  				goto again;
  #endif
  
  			case EWOULDBLOCK:
  				return (0);
  
  			case ENXIO:
  				/*
  				 * The device on which we're capturing
  				 * went away.
  				 *
  				 * XXX - we should really return
  				 * PCAP_ERROR_IFACE_NOT_UP, but
  				 * pcap_dispatch() etc. aren't
  				 * defined to retur that.
  				 */
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "The interface went down");
  				return (PCAP_ERROR);
  
  #if defined(sun) && !defined(BSD) && !defined(__svr4__) && !defined(__SVR4)
  			/*
  			 * Due to a SunOS bug, after 2^31 bytes, the kernel
  			 * file offset overflows and read fails with EINVAL.
  			 * The lseek() to 0 will fix things.
  			 */
  			case EINVAL:
  				if (lseek(p->fd, 0L, SEEK_CUR) +
  				    p->bufsize < 0) {
  					(void)lseek(p->fd, 0L, SEEK_SET);
  					goto again;
  				}
  				/* fall through */
  #endif
  			}
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s",
  			    pcap_strerror(errno));
  			return (PCAP_ERROR);
  		}
  		bp = (u_char *)p->buffer;
  	} else
  		bp = p->bp;
  
  	/*
  	 * Loop through each packet.
  	 */
  #ifdef BIOCSTSTAMP
  #define bhp ((struct bpf_xhdr *)bp)
  #else
  #define bhp ((struct bpf_hdr *)bp)
  #endif
  	ep = bp + cc;
  #ifdef PCAP_FDDIPAD
  	pad = p->fddipad;
  #endif
  	while (bp < ep) {
  		register u_int caplen, hdrlen;
  
  		/*
  		 * Has "pcap_breakloop()" been called?
  		 * If so, return immediately - if we haven't read any
  		 * packets, clear the flag and return PCAP_ERROR_BREAK
  		 * to indicate that we were told to break out of the loop,
  		 * otherwise leave the flag set, so that the *next* call
  		 * will break out of the loop without having read any
  		 * packets, and return the number of packets we've
  		 * processed so far.
  		 */
  		if (p->break_loop) {
  			p->bp = bp;
  			p->cc = ep - bp;
  			/*
  			 * ep is set based on the return value of read(),
  			 * but read() from a BPF device doesn't necessarily
  			 * return a value that's a multiple of the alignment
  			 * value for BPF_WORDALIGN().  However, whenever we
  			 * increment bp, we round up the increment value by
  			 * a value rounded up by BPF_WORDALIGN(), so we
  			 * could increment bp past ep after processing the
  			 * last packet in the buffer.
  			 *
  			 * We treat ep < bp as an indication that this
  			 * happened, and just set p->cc to 0.
  			 */
  			if (p->cc < 0)
  				p->cc = 0;
  			if (n == 0) {
  				p->break_loop = 0;
  				return (PCAP_ERROR_BREAK);
  			} else
  				return (n);
  		}
  
  		caplen = bhp->bh_caplen;
  		hdrlen = bhp->bh_hdrlen;
  		datap = bp + hdrlen;
  		/*
  		 * Short-circuit evaluation: if using BPF filter
  		 * in kernel, no need to do it now - we already know
  		 * the packet passed the filter.
  		 *
  #ifdef PCAP_FDDIPAD
  		 * Note: the filter code was generated assuming
  		 * that p->fddipad was the amount of padding
  		 * before the header, as that's what's required
  		 * in the kernel, so we run the filter before
  		 * skipping that padding.
  #endif
  		 */
  		if (pb->filtering_in_kernel ||
  		    bpf_filter(p->fcode.bf_insns, datap, bhp->bh_datalen, caplen)) {
  			struct pcap_pkthdr pkthdr;
  #ifdef BIOCSTSTAMP
  			struct bintime bt;
  
  			bt.sec = bhp->bh_tstamp.bt_sec;
  			bt.frac = bhp->bh_tstamp.bt_frac;
  			if (p->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
  				struct timespec ts;
  
  				bintime2timespec(&bt, &ts);
  				pkthdr.ts.tv_sec = ts.tv_sec;
  				pkthdr.ts.tv_usec = ts.tv_nsec;
  			} else {
  				struct timeval tv;
  
  				bintime2timeval(&bt, &tv);
  				pkthdr.ts.tv_sec = tv.tv_sec;
  				pkthdr.ts.tv_usec = tv.tv_usec;
  			}
  #else
  			pkthdr.ts.tv_sec = bhp->bh_tstamp.tv_sec;
  #ifdef _AIX
  			/*
  			 * AIX's BPF returns seconds/nanoseconds time
  			 * stamps, not seconds/microseconds time stamps.
  			 */
  			pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec/1000;
  #else
  			pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec;
  #endif
  #endif /* BIOCSTSTAMP */
  #ifdef PCAP_FDDIPAD
  			if (caplen > pad)
  				pkthdr.caplen = caplen - pad;
  			else
  				pkthdr.caplen = 0;
  			if (bhp->bh_datalen > pad)
  				pkthdr.len = bhp->bh_datalen - pad;
  			else
  				pkthdr.len = 0;
  			datap += pad;
  #else
  			pkthdr.caplen = caplen;
  			pkthdr.len = bhp->bh_datalen;
  #endif
  			(*callback)(user, &pkthdr, datap);
  			bp += BPF_WORDALIGN(caplen + hdrlen);
  			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
  				p->bp = bp;
  				p->cc = ep - bp;
  				/*
  				 * See comment above about p->cc < 0.
  				 */
  				if (p->cc < 0)
  					p->cc = 0;
  				return (n);
  			}
  		} else {
  			/*
  			 * Skip this packet.
  			 */
  			bp += BPF_WORDALIGN(caplen + hdrlen);
  		}
  	}
  #undef bhp
  	p->cc = 0;
  	return (n);
  }
  
  static int
  pcap_inject_bpf(pcap_t *p, const void *buf, size_t size)
  {
  	int ret;
  
  	ret = write(p->fd, buf, size);
  #ifdef __APPLE__
  	if (ret == -1 && errno == EAFNOSUPPORT) {
  		/*
  		 * In Mac OS X, there's a bug wherein setting the
  		 * BIOCSHDRCMPLT flag causes writes to fail; see,
  		 * for example:
  		 *
  		 *	http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/BIOCSHDRCMPLT-10.3.3.patch
  		 *
  		 * So, if, on OS X, we get EAFNOSUPPORT from the write, we
  		 * assume it's due to that bug, and turn off that flag
  		 * and try again.  If we succeed, it either means that
  		 * somebody applied the fix from that URL, or other patches
  		 * for that bug from
  		 *
  		 *	http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/
  		 *
  		 * and are running a Darwin kernel with those fixes, or
  		 * that Apple fixed the problem in some OS X release.
  		 */
  		u_int spoof_eth_src = 0;
  
  		if (ioctl(p->fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) {
  			(void)pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "send: can't turn off BIOCSHDRCMPLT: %s",
  			    pcap_strerror(errno));
  			return (PCAP_ERROR);
  		}
  
  		/*
  		 * Now try the write again.
  		 */
  		ret = write(p->fd, buf, size);
  	}
  #endif /* __APPLE__ */
  	if (ret == -1) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
  		    pcap_strerror(errno));
  		return (PCAP_ERROR);
  	}
  	return (ret);
  }
  
  #ifdef _AIX
  static int
  bpf_odminit(char *errbuf)
  {
  	char *errstr;
  
  	if (odm_initialize() == -1) {
  		if (odm_err_msg(odmerrno, &errstr) == -1)
  			errstr = "Unknown error";
  		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  		    "bpf_load: odm_initialize failed: %s",
  		    errstr);
  		return (PCAP_ERROR);
  	}
  
  	if ((odmlockid = odm_lock("/etc/objrepos/config_lock", ODM_WAIT)) == -1) {
  		if (odm_err_msg(odmerrno, &errstr) == -1)
  			errstr = "Unknown error";
  		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  		    "bpf_load: odm_lock of /etc/objrepos/config_lock failed: %s",
  		    errstr);
  		(void)odm_terminate();
  		return (PCAP_ERROR);
  	}
  
  	return (0);
  }
  
  static int
  bpf_odmcleanup(char *errbuf)
  {
  	char *errstr;
  
  	if (odm_unlock(odmlockid) == -1) {
  		if (errbuf != NULL) {
  			if (odm_err_msg(odmerrno, &errstr) == -1)
  				errstr = "Unknown error";
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "bpf_load: odm_unlock failed: %s",
  			    errstr);
  		}
  		return (PCAP_ERROR);
  	}
  
  	if (odm_terminate() == -1) {
  		if (errbuf != NULL) {
  			if (odm_err_msg(odmerrno, &errstr) == -1)
  				errstr = "Unknown error";
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "bpf_load: odm_terminate failed: %s",
  			    errstr);
  		}
  		return (PCAP_ERROR);
  	}
  
  	return (0);
  }
  
  static int
  bpf_load(char *errbuf)
  {
  	long major;
  	int *minors;
  	int numminors, i, rc;
  	char buf[1024];
  	struct stat sbuf;
  	struct bpf_config cfg_bpf;
  	struct cfg_load cfg_ld;
  	struct cfg_kmod cfg_km;
  
  	/*
  	 * This is very very close to what happens in the real implementation
  	 * but I've fixed some (unlikely) bug situations.
  	 */
  	if (bpfloadedflag)
  		return (0);
  
  	if (bpf_odminit(errbuf) == PCAP_ERROR)
  		return (PCAP_ERROR);
  
  	major = genmajor(BPF_NAME);
  	if (major == -1) {
  		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  		    "bpf_load: genmajor failed: %s", pcap_strerror(errno));
  		(void)bpf_odmcleanup(NULL);
  		return (PCAP_ERROR);
  	}
  
  	minors = getminor(major, &numminors, BPF_NAME);
  	if (!minors) {
  		minors = genminor("bpf", major, 0, BPF_MINORS, 1, 1);
  		if (!minors) {
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "bpf_load: genminor failed: %s",
  			    pcap_strerror(errno));
  			(void)bpf_odmcleanup(NULL);
  			return (PCAP_ERROR);
  		}
  	}
  
  	if (bpf_odmcleanup(errbuf) == PCAP_ERROR)
  		return (PCAP_ERROR);
  
  	rc = stat(BPF_NODE "0", &sbuf);
  	if (rc == -1 && errno != ENOENT) {
  		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  		    "bpf_load: can't stat %s: %s",
  		    BPF_NODE "0", pcap_strerror(errno));
  		return (PCAP_ERROR);
  	}
  
  	if (rc == -1 || getmajor(sbuf.st_rdev) != major) {
  		for (i = 0; i < BPF_MINORS; i++) {
  			sprintf(buf, "%s%d", BPF_NODE, i);
  			unlink(buf);
  			if (mknod(buf, S_IRUSR | S_IFCHR, domakedev(major, i)) == -1) {
  				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  				    "bpf_load: can't mknod %s: %s",
  				    buf, pcap_strerror(errno));
  				return (PCAP_ERROR);
  			}
  		}
  	}
  
  	/* Check if the driver is loaded */
  	memset(&cfg_ld, 0x0, sizeof(cfg_ld));
  	cfg_ld.path = buf;
  	sprintf(cfg_ld.path, "%s/%s", DRIVER_PATH, BPF_NAME);
  	if ((sysconfig(SYS_QUERYLOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) ||
  	    (cfg_ld.kmid == 0)) {
  		/* Driver isn't loaded, load it now */
  		if (sysconfig(SYS_SINGLELOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) {
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "bpf_load: could not load driver: %s",
  			    strerror(errno));
  			return (PCAP_ERROR);
  		}
  	}
  
  	/* Configure the driver */
  	cfg_km.cmd = CFG_INIT;
  	cfg_km.kmid = cfg_ld.kmid;
  	cfg_km.mdilen = sizeof(cfg_bpf);
  	cfg_km.mdiptr = (void *)&cfg_bpf;
  	for (i = 0; i < BPF_MINORS; i++) {
  		cfg_bpf.devno = domakedev(major, i);
  		if (sysconfig(SYS_CFGKMOD, (void *)&cfg_km, sizeof(cfg_km)) == -1) {
  			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "bpf_load: could not configure driver: %s",
  			    strerror(errno));
  			return (PCAP_ERROR);
  		}
  	}
  
  	bpfloadedflag = 1;
  
  	return (0);
  }
  #endif
  
  /*
   * Undo any operations done when opening the device when necessary.
   */
  static void
  pcap_cleanup_bpf(pcap_t *p)
  {
  	struct pcap_bpf *pb = p->priv;
  #ifdef HAVE_BSD_IEEE80211
  	int sock;
  	struct ifmediareq req;
  	struct ifreq ifr;
  #endif
  
  	if (pb->must_do_on_close != 0) {
  		/*
  		 * There's something we have to do when closing this
  		 * pcap_t.
  		 */
  #ifdef HAVE_BSD_IEEE80211
  		if (pb->must_do_on_close & MUST_CLEAR_RFMON) {
  			/*
  			 * We put the interface into rfmon mode;
  			 * take it out of rfmon mode.
  			 *
  			 * XXX - if somebody else wants it in rfmon
  			 * mode, this code cannot know that, so it'll take
  			 * it out of rfmon mode.
  			 */
  			sock = socket(AF_INET, SOCK_DGRAM, 0);
  			if (sock == -1) {
  				fprintf(stderr,
  				    "Can't restore interface flags (socket() failed: %s).\n"
  				    "Please adjust manually.\n",
  				    strerror(errno));
  			} else {
  				memset(&req, 0, sizeof(req));
  				strncpy(req.ifm_name, pb->device,
  				    sizeof(req.ifm_name));
  				if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
  					fprintf(stderr,
  					    "Can't restore interface flags (SIOCGIFMEDIA failed: %s).\n"
  					    "Please adjust manually.\n",
  					    strerror(errno));
  				} else {
  					if (req.ifm_current & IFM_IEEE80211_MONITOR) {
  						/*
  						 * Rfmon mode is currently on;
  						 * turn it off.
  						 */
  						memset(&ifr, 0, sizeof(ifr));
  						(void)strncpy(ifr.ifr_name,
  						    pb->device,
  						    sizeof(ifr.ifr_name));
  						ifr.ifr_media =
  						    req.ifm_current & ~IFM_IEEE80211_MONITOR;
  						if (ioctl(sock, SIOCSIFMEDIA,
  						    &ifr) == -1) {
  							fprintf(stderr,
  							    "Can't restore interface flags (SIOCSIFMEDIA failed: %s).\n"
  							    "Please adjust manually.\n",
  							    strerror(errno));
  						}
  					}
  				}
  				close(sock);
  			}
  		}
  #endif /* HAVE_BSD_IEEE80211 */
  
  #if defined(__FreeBSD__) && defined(SIOCIFCREATE2)
  		/*
  		 * Attempt to destroy the usbusN interface that we created.
  		 */
  		if (pb->must_do_on_close & MUST_DESTROY_USBUS) {
  			if (if_nametoindex(pb->device) > 0) {
  				int s;
  
  				s = socket(AF_LOCAL, SOCK_DGRAM, 0);
  				if (s >= 0) {
  					strlcpy(ifr.ifr_name, pb->device,
  					    sizeof(ifr.ifr_name));
  					ioctl(s, SIOCIFDESTROY, &ifr);
  					close(s);
  				}
  			}
  		}
  #endif /* defined(__FreeBSD__) && defined(SIOCIFCREATE2) */
  		/*
  		 * Take this pcap out of the list of pcaps for which we
  		 * have to take the interface out of some mode.
  		 */
  		pcap_remove_from_pcaps_to_close(p);
  		pb->must_do_on_close = 0;
  	}
  
  #ifdef HAVE_ZEROCOPY_BPF
  	if (pb->zerocopy) {
  		/*
  		 * Delete the mappings.  Note that p->buffer gets
  		 * initialized to one of the mmapped regions in
  		 * this case, so do not try and free it directly;
  		 * null it out so that pcap_cleanup_live_common()
  		 * doesn't try to free it.
  		 */
  		if (pb->zbuf1 != MAP_FAILED && pb->zbuf1 != NULL)
  			(void) munmap(pb->zbuf1, pb->zbufsize);
  		if (pb->zbuf2 != MAP_FAILED && pb->zbuf2 != NULL)
  			(void) munmap(pb->zbuf2, pb->zbufsize);
  		p->buffer = NULL;
  	}
  #endif
  	if (pb->device != NULL) {
  		free(pb->device);
  		pb->device = NULL;
  	}
  	pcap_cleanup_live_common(p);
  }
  
  static int
  check_setif_failure(pcap_t *p, int error)
  {
  #ifdef __APPLE__
  	int fd;
  	struct ifreq ifr;
  	int err;
  #endif
  
  	if (error == ENXIO) {
  		/*
  		 * No such device exists.
  		 */
  #ifdef __APPLE__
  		if (p->opt.rfmon && strncmp(p->opt.device, "wlt", 3) == 0) {
  			/*
  			 * Monitor mode was requested, and we're trying
  			 * to open a "wltN" device.  Assume that this
  			 * is 10.4 and that we were asked to open an
  			 * "enN" device; if that device exists, return
  			 * "monitor mode not supported on the device".
  			 */
  			fd = socket(AF_INET, SOCK_DGRAM, 0);
  			if (fd != -1) {
  				strlcpy(ifr.ifr_name, "en",
  				    sizeof(ifr.ifr_name));
  				strlcat(ifr.ifr_name, p->opt.device + 3,
  				    sizeof(ifr.ifr_name));
  				if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
  					/*
  					 * We assume this failed because
  					 * the underlying device doesn't
  					 * exist.
  					 */
  					err = PCAP_ERROR_NO_SUCH_DEVICE;
  					pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  					    "SIOCGIFFLAGS on %s failed: %s",
  					    ifr.ifr_name, pcap_strerror(errno));
  				} else {
  					/*
  					 * The underlying "enN" device
  					 * exists, but there's no
  					 * corresponding "wltN" device;
  					 * that means that the "enN"
  					 * device doesn't support
  					 * monitor mode, probably because
  					 * it's an Ethernet device rather
  					 * than a wireless device.
  					 */
  					err = PCAP_ERROR_RFMON_NOTSUP;
  				}
  				close(fd);
  			} else {
  				/*
  				 * We can't find out whether there's
  				 * an underlying "enN" device, so
  				 * just report "no such device".
  				 */
  				err = PCAP_ERROR_NO_SUCH_DEVICE;
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "socket() failed: %s",
  				    pcap_strerror(errno));
  			}
  			return (err);
  		}
  #endif
  		/*
  		 * No such device.
  		 */
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF failed: %s",
  		    pcap_strerror(errno));
  		return (PCAP_ERROR_NO_SUCH_DEVICE);
  	} else if (errno == ENETDOWN) {
  		/*
  		 * Return a "network down" indication, so that
  		 * the application can report that rather than
  		 * saying we had a mysterious failure and
  		 * suggest that they report a problem to the
  		 * libpcap developers.
  		 */
  		return (PCAP_ERROR_IFACE_NOT_UP);
  	} else {
  		/*
  		 * Some other error; fill in the error string, and
  		 * return PCAP_ERROR.
  		 */
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
  		    p->opt.device, pcap_strerror(errno));
  		return (PCAP_ERROR);
  	}
  }
  
  /*
   * Default capture buffer size.
   * 32K isn't very much for modern machines with fast networks; we
   * pick .5M, as that's the maximum on at least some systems with BPF.
   *
   * However, on AIX 3.5, the larger buffer sized caused unrecoverable
   * read failures under stress, so we leave it as 32K; yet another
   * place where AIX's BPF is broken.
   */
  #ifdef _AIX
  #define DEFAULT_BUFSIZE	32768
  #else
  #define DEFAULT_BUFSIZE	524288
  #endif
  
  static int
  pcap_activate_bpf(pcap_t *p)
  {
  	struct pcap_bpf *pb = p->priv;
  	int status = 0;
  #ifdef HAVE_BSD_IEEE80211
  	int retv;
  #endif
  	int fd;
  #ifdef LIFNAMSIZ
  	char *zonesep;
  	struct lifreq ifr;
  	char *ifrname = ifr.lifr_name;
  	const size_t ifnamsiz = sizeof(ifr.lifr_name);
  #else
  	struct ifreq ifr;
  	char *ifrname = ifr.ifr_name;
  	const size_t ifnamsiz = sizeof(ifr.ifr_name);
  #endif
  	struct bpf_version bv;
  #ifdef __APPLE__
  	int sockfd;
  	char *wltdev = NULL;
  #endif
  #ifdef BIOCGDLTLIST
  	struct bpf_dltlist bdl;
  #if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)
  	int new_dlt;
  #endif
  #endif /* BIOCGDLTLIST */
  #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT)
  	u_int spoof_eth_src = 1;
  #endif
  	u_int v;
  	struct bpf_insn total_insn;
  	struct bpf_program total_prog;
  	struct utsname osinfo;
  	int have_osinfo = 0;
  #ifdef HAVE_ZEROCOPY_BPF
  	struct bpf_zbuf bz;
  	u_int bufmode, zbufmax;
  #endif
  
  	fd = bpf_open(p->errbuf);
  	if (fd < 0) {
  		status = fd;
  		goto bad;
  	}
  
  	p->fd = fd;
  
  	if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  	if (bv.bv_major != BPF_MAJOR_VERSION ||
  	    bv.bv_minor < BPF_MINOR_VERSION) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  		    "kernel bpf filter out of date");
  		status = PCAP_ERROR;
  		goto bad;
  	}
  
  #if defined(LIFNAMSIZ) && defined(ZONENAME_MAX) && defined(lifr_zoneid)
  	/*
  	 * Retrieve the zoneid of the zone we are currently executing in.
  	 */
  	if ((ifr.lifr_zoneid = getzoneid()) == -1) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "getzoneid(): %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  	/*
  	 * Check if the given source datalink name has a '/' separated
  	 * zonename prefix string.  The zonename prefixed source datalink can
  	 * be used by pcap consumers in the Solaris global zone to capture
  	 * traffic on datalinks in non-global zones.  Non-global zones
  	 * do not have access to datalinks outside of their own namespace.
  	 */
  	if ((zonesep = strchr(p->opt.device, '/')) != NULL) {
  		char path_zname[ZONENAME_MAX];
  		int  znamelen;
  		char *lnamep;
  
  		if (ifr.lifr_zoneid != GLOBAL_ZONEID) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "zonename/linkname only valid in global zone.");
  			status = PCAP_ERROR;
  			goto bad;
  		}
  		znamelen = zonesep - p->opt.device;
  		(void) strlcpy(path_zname, p->opt.device, znamelen + 1);
  		ifr.lifr_zoneid = getzoneidbyname(path_zname);
  		if (ifr.lifr_zoneid == -1) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "getzoneidbyname(%s): %s", path_zname,
  			pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  		lnamep = strdup(zonesep + 1);
  		if (lnamep == NULL) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
  			    pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  		free(p->opt.device);
  		p->opt.device = lnamep;
  	}
  #endif
  
  	pb->device = strdup(p->opt.device);
  	if (pb->device == NULL) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
  		     pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  
  	/*
  	 * Attempt to find out the version of the OS on which we're running.
  	 */
  	if (uname(&osinfo) == 0)
  		have_osinfo = 1;
  
  #ifdef __APPLE__
  	/*
  	 * See comment in pcap_can_set_rfmon_bpf() for an explanation
  	 * of why we check the version number.
  	 */
  	if (p->opt.rfmon) {
  		if (have_osinfo) {
  			/*
  			 * We assume osinfo.sysname is "Darwin", because
  			 * __APPLE__ is defined.  We just check the version.
  			 */
  			if (osinfo.release[0] < '8' &&
  			    osinfo.release[1] == '.') {
  				/*
  				 * 10.3 (Darwin 7.x) or earlier.
  				 */
  				status = PCAP_ERROR_RFMON_NOTSUP;
  				goto bad;
  			}
  			if (osinfo.release[0] == '8' &&
  			    osinfo.release[1] == '.') {
  				/*
  				 * 10.4 (Darwin 8.x).  s/en/wlt/
  				 */
  				if (strncmp(p->opt.device, "en", 2) != 0) {
  					/*
  					 * Not an enN device; check
  					 * whether the device even exists.
  					 */
  					sockfd = socket(AF_INET, SOCK_DGRAM, 0);
  					if (sockfd != -1) {
  						strlcpy(ifrname,
  						    p->opt.device, ifnamsiz);
  						if (ioctl(sockfd, SIOCGIFFLAGS,
  						    (char *)&ifr) < 0) {
  							/*
  							 * We assume this
  							 * failed because
  							 * the underlying
  							 * device doesn't
  							 * exist.
  							 */
  							status = PCAP_ERROR_NO_SUCH_DEVICE;
  							pcap_snprintf(p->errbuf,
  							    PCAP_ERRBUF_SIZE,
  							    "SIOCGIFFLAGS failed: %s",
  							    pcap_strerror(errno));
  						} else
  							status = PCAP_ERROR_RFMON_NOTSUP;
  						close(sockfd);
  					} else {
  						/*
  						 * We can't find out whether
  						 * the device exists, so just
  						 * report "no such device".
  						 */
  						status = PCAP_ERROR_NO_SUCH_DEVICE;
  						pcap_snprintf(p->errbuf,
  						    PCAP_ERRBUF_SIZE,
  						    "socket() failed: %s",
  						    pcap_strerror(errno));
  					}
  					goto bad;
  				}
  				wltdev = malloc(strlen(p->opt.device) + 2);
  				if (wltdev == NULL) {
  					(void)pcap_snprintf(p->errbuf,
  					    PCAP_ERRBUF_SIZE, "malloc: %s",
  					    pcap_strerror(errno));
  					status = PCAP_ERROR;
  					goto bad;
  				}
  				strcpy(wltdev, "wlt");
  				strcat(wltdev, p->opt.device + 2);
  				free(p->opt.device);
  				p->opt.device = wltdev;
  			}
  			/*
  			 * Everything else is 10.5 or later; for those,
  			 * we just open the enN device, and set the DLT.
  			 */
  		}
  	}
  #endif /* __APPLE__ */
  
  	/*
  	 * If this is FreeBSD, and the device name begins with "usbus",
  	 * try to create the interface if it's not available.
  	 */
  #if defined(__FreeBSD__) && defined(SIOCIFCREATE2)
  	if (strncmp(p->opt.device, usbus_prefix, USBUS_PREFIX_LEN) == 0) {
  		/*
  		 * Do we already have an interface with that name?
  		 */
  		if (if_nametoindex(p->opt.device) == 0) {
  			/*
  			 * No.  We need to create it, and, if we
  			 * succeed, remember that we should destroy
  			 * it when the pcap_t is closed.
  			 */
  			int s;
  
  			/*
  			 * Open a socket to use for ioctls to
  			 * create the interface.
  			 */
  			s = socket(AF_LOCAL, SOCK_DGRAM, 0);
  			if (s < 0) {
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "Can't open socket: %s",
  				    pcap_strerror(errno));
  				status = PCAP_ERROR;
  				goto bad;
  			}
  
  			/*
  			 * If we haven't already done so, arrange to have
  			 * "pcap_close_all()" called when we exit.
  			 */
  			if (!pcap_do_addexit(p)) {
  				/*
  				 * "atexit()" failed; don't create the
  				 * interface, just give up.
  				 */
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				     "atexit failed");
  				close(s);
  				status = PCAP_ERROR;
  				goto bad;
  			}
  
  			/*
  			 * Create the interface.
  			 */
  			strlcpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
  			if (ioctl(s, SIOCIFCREATE2, &ifr) < 0) {
  				if (errno == EINVAL) {
  					pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  					    "Invalid USB bus interface %s",
  					    p->opt.device);
  				} else {
  					pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  					    "Can't create interface for %s: %s",
  					    p->opt.device, pcap_strerror(errno));
  				}
  				close(s);
  				status = PCAP_ERROR;
  				goto bad;
  			}
  
  			/*
  			 * Make sure we clean this up when we close.
  			 */
  			pb->must_do_on_close |= MUST_DESTROY_USBUS;
  
  			/*
  			 * Add this to the list of pcaps to close when we exit.
  			 */
  			pcap_add_to_pcaps_to_close(p);
  		}
  	}
  #endif /* defined(__FreeBSD__) && defined(SIOCIFCREATE2) */
  
  #ifdef HAVE_ZEROCOPY_BPF
  	/*
  	 * If the BPF extension to set buffer mode is present, try setting
  	 * the mode to zero-copy.  If that fails, use regular buffering.  If
  	 * it succeeds but other setup fails, return an error to the user.
  	 */
  	bufmode = BPF_BUFMODE_ZBUF;
  	if (ioctl(fd, BIOCSETBUFMODE, (caddr_t)&bufmode) == 0) {
  		/*
  		 * We have zerocopy BPF; use it.
  		 */
  		pb->zerocopy = 1;
  
  		/*
  		 * How to pick a buffer size: first, query the maximum buffer
  		 * size supported by zero-copy.  This also lets us quickly
  		 * determine whether the kernel generally supports zero-copy.
  		 * Then, if a buffer size was specified, use that, otherwise
  		 * query the default buffer size, which reflects kernel
  		 * policy for a desired default.  Round to the nearest page
  		 * size.
  		 */
  		if (ioctl(fd, BIOCGETZMAX, (caddr_t)&zbufmax) < 0) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGETZMAX: %s",
  			    pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  
  		if (p->opt.buffer_size != 0) {
  			/*
  			 * A buffer size was explicitly specified; use it.
  			 */
  			v = p->opt.buffer_size;
  		} else {
  			if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) ||
  			    v < DEFAULT_BUFSIZE)
  				v = DEFAULT_BUFSIZE;
  		}
  #ifndef roundup
  #define roundup(x, y)   ((((x)+((y)-1))/(y))*(y))  /* to any y */
  #endif
  		pb->zbufsize = roundup(v, getpagesize());
  		if (pb->zbufsize > zbufmax)
  			pb->zbufsize = zbufmax;
  		pb->zbuf1 = mmap(NULL, pb->zbufsize, PROT_READ | PROT_WRITE,
  		    MAP_ANON, -1, 0);
  		pb->zbuf2 = mmap(NULL, pb->zbufsize, PROT_READ | PROT_WRITE,
  		    MAP_ANON, -1, 0);
  		if (pb->zbuf1 == MAP_FAILED || pb->zbuf2 == MAP_FAILED) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "mmap: %s",
  			    pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  		memset(&bz, 0, sizeof(bz)); /* bzero() deprecated, replaced with memset() */
  		bz.bz_bufa = pb->zbuf1;
  		bz.bz_bufb = pb->zbuf2;
  		bz.bz_buflen = pb->zbufsize;
  		if (ioctl(fd, BIOCSETZBUF, (caddr_t)&bz) < 0) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETZBUF: %s",
  			    pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  		(void)strncpy(ifrname, p->opt.device, ifnamsiz);
  		if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
  			    p->opt.device, pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  		v = pb->zbufsize - sizeof(struct bpf_zbuf_header);
  	} else
  #endif
  	{
  		/*
  		 * We don't have zerocopy BPF.
  		 * Set the buffer size.
  		 */
  		if (p->opt.buffer_size != 0) {
  			/*
  			 * A buffer size was explicitly specified; use it.
  			 */
  			if (ioctl(fd, BIOCSBLEN,
  			    (caddr_t)&p->opt.buffer_size) < 0) {
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "BIOCSBLEN: %s: %s", p->opt.device,
  				    pcap_strerror(errno));
  				status = PCAP_ERROR;
  				goto bad;
  			}
  
  			/*
  			 * Now bind to the device.
  			 */
  			(void)strncpy(ifrname, p->opt.device, ifnamsiz);
  #ifdef BIOCSETLIF
  			if (ioctl(fd, BIOCSETLIF, (caddr_t)&ifr) < 0)
  #else
  			if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0)
  #endif
  			{
  				status = check_setif_failure(p, errno);
  				goto bad;
  			}
  		} else {
  			/*
  			 * No buffer size was explicitly specified.
  			 *
  			 * Try finding a good size for the buffer;
  			 * DEFAULT_BUFSIZE may be too big, so keep
  			 * cutting it in half until we find a size
  			 * that works, or run out of sizes to try.
  			 * If the default is larger, don't make it smaller.
  			 */
  			if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) ||
  			    v < DEFAULT_BUFSIZE)
  				v = DEFAULT_BUFSIZE;
  			for ( ; v != 0; v >>= 1) {
  				/*
  				 * Ignore the return value - this is because the
  				 * call fails on BPF systems that don't have
  				 * kernel malloc.  And if the call fails, it's
  				 * no big deal, we just continue to use the
  				 * standard buffer size.
  				 */
  				(void) ioctl(fd, BIOCSBLEN, (caddr_t)&v);
  
  				(void)strncpy(ifrname, p->opt.device, ifnamsiz);
  #ifdef BIOCSETLIF
  				if (ioctl(fd, BIOCSETLIF, (caddr_t)&ifr) >= 0)
  #else
  				if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0)
  #endif
  					break;	/* that size worked; we're done */
  
  				if (errno != ENOBUFS) {
  					status = check_setif_failure(p, errno);
  					goto bad;
  				}
  			}
  
  			if (v == 0) {
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "BIOCSBLEN: %s: No buffer size worked",
  				    p->opt.device);
  				status = PCAP_ERROR;
  				goto bad;
  			}
  		}
  	}
  
  	/* Get the data link layer type. */
  	if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  
  #ifdef _AIX
  	/*
  	 * AIX's BPF returns IFF_ types, not DLT_ types, in BIOCGDLT.
  	 */
  	switch (v) {
  
  	case IFT_ETHER:
  	case IFT_ISO88023:
  		v = DLT_EN10MB;
  		break;
  
  	case IFT_FDDI:
  		v = DLT_FDDI;
  		break;
  
  	case IFT_ISO88025:
  		v = DLT_IEEE802;
  		break;
  
  	case IFT_LOOP:
  		v = DLT_NULL;
  		break;
  
  	default:
  		/*
  		 * We don't know what to map this to yet.
  		 */
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown interface type %u",
  		    v);
  		status = PCAP_ERROR;
  		goto bad;
  	}
  #endif
  #if _BSDI_VERSION - 0 >= 199510
  	/* The SLIP and PPP link layer header changed in BSD/OS 2.1 */
  	switch (v) {
  
  	case DLT_SLIP:
  		v = DLT_SLIP_BSDOS;
  		break;
  
  	case DLT_PPP:
  		v = DLT_PPP_BSDOS;
  		break;
  
  	case 11:	/*DLT_FR*/
  		v = DLT_FRELAY;
  		break;
  
  	case 12:	/*DLT_C_HDLC*/
  		v = DLT_CHDLC;
  		break;
  	}
  #endif
  
  #ifdef BIOCGDLTLIST
  	/*
  	 * We know the default link type -- now determine all the DLTs
  	 * this interface supports.  If this fails with EINVAL, it's
  	 * not fatal; we just don't get to use the feature later.
  	 */
  	if (get_dlt_list(fd, v, &bdl, p->errbuf) == -1) {
  		status = PCAP_ERROR;
  		goto bad;
  	}
  	p->dlt_count = bdl.bfl_len;
  	p->dlt_list = bdl.bfl_list;
  
  #ifdef __APPLE__
  	/*
  	 * Monitor mode fun, continued.
  	 *
  	 * For 10.5 and, we're assuming, later releases, as noted above,
  	 * 802.1 adapters that support monitor mode offer both DLT_EN10MB,
  	 * DLT_IEEE802_11, and possibly some 802.11-plus-radio-information
  	 * DLT_ value.  Choosing one of the 802.11 DLT_ values will turn
  	 * monitor mode on.
  	 *
  	 * Therefore, if the user asked for monitor mode, we filter out
  	 * the DLT_EN10MB value, as you can't get that in monitor mode,
  	 * and, if the user didn't ask for monitor mode, we filter out
  	 * the 802.11 DLT_ values, because selecting those will turn
  	 * monitor mode on.  Then, for monitor mode, if an 802.11-plus-
  	 * radio DLT_ value is offered, we try to select that, otherwise
  	 * we try to select DLT_IEEE802_11.
  	 */
  	if (have_osinfo) {
  		if (isdigit((unsigned)osinfo.release[0]) &&
  		     (osinfo.release[0] == '9' ||
  		     isdigit((unsigned)osinfo.release[1]))) {
  			/*
  			 * 10.5 (Darwin 9.x), or later.
  			 */
  			new_dlt = find_802_11(&bdl);
  			if (new_dlt != -1) {
  				/*
  				 * We have at least one 802.11 DLT_ value,
  				 * so this is an 802.11 interface.
  				 * new_dlt is the best of the 802.11
  				 * DLT_ values in the list.
  				 */
  				if (p->opt.rfmon) {
  					/*
  					 * Our caller wants monitor mode.
  					 * Purge DLT_EN10MB from the list
  					 * of link-layer types, as selecting
  					 * it will keep monitor mode off.
  					 */
  					remove_en(p);
  
  					/*
  					 * If the new mode we want isn't
  					 * the default mode, attempt to
  					 * select the new mode.
  					 */
  					if ((u_int)new_dlt != v) {
  						if (ioctl(p->fd, BIOCSDLT,
  						    &new_dlt) != -1) {
  							/*
  							 * We succeeded;
  							 * make this the
  							 * new DLT_ value.
  							 */
  							v = new_dlt;
  						}
  					}
  				} else {
  					/*
  					 * Our caller doesn't want
  					 * monitor mode.  Unless this
  					 * is being done by pcap_open_live(),
  					 * purge the 802.11 link-layer types
  					 * from the list, as selecting
  					 * one of them will turn monitor
  					 * mode on.
  					 */
  					if (!p->oldstyle)
  						remove_802_11(p);
  				}
  			} else {
  				if (p->opt.rfmon) {
  					/*
  					 * The caller requested monitor
  					 * mode, but we have no 802.11
  					 * link-layer types, so they
  					 * can't have it.
  					 */
  					status = PCAP_ERROR_RFMON_NOTSUP;
  					goto bad;
  				}
  			}
  		}
  	}
  #elif defined(HAVE_BSD_IEEE80211)
  	/*
  	 * *BSD with the new 802.11 ioctls.
  	 * Do we want monitor mode?
  	 */
  	if (p->opt.rfmon) {
  		/*
  		 * Try to put the interface into monitor mode.
  		 */
  		retv = monitor_mode(p, 1);
  		if (retv != 0) {
  			/*
  			 * We failed.
  			 */
  			status = retv;
  			goto bad;
  		}
  
  		/*
  		 * We're in monitor mode.
  		 * Try to find the best 802.11 DLT_ value and, if we
  		 * succeed, try to switch to that mode if we're not
  		 * already in that mode.
  		 */
  		new_dlt = find_802_11(&bdl);
  		if (new_dlt != -1) {
  			/*
  			 * We have at least one 802.11 DLT_ value.
  			 * new_dlt is the best of the 802.11
  			 * DLT_ values in the list.
  			 *
  			 * If the new mode we want isn't the default mode,
  			 * attempt to select the new mode.
  			 */
  			if ((u_int)new_dlt != v) {
  				if (ioctl(p->fd, BIOCSDLT, &new_dlt) != -1) {
  					/*
  					 * We succeeded; make this the
  					 * new DLT_ value.
  					 */
  					v = new_dlt;
  				}
  			}
  		}
  	}
  #endif /* various platforms */
  #endif /* BIOCGDLTLIST */
  
  	/*
  	 * If this is an Ethernet device, and we don't have a DLT_ list,
  	 * give it a list with DLT_EN10MB and DLT_DOCSIS.  (That'd give
  	 * 802.11 interfaces DLT_DOCSIS, which isn't the right thing to
  	 * do, but there's not much we can do about that without finding
  	 * some other way of determining whether it's an Ethernet or 802.11
  	 * device.)
  	 */
  	if (v == DLT_EN10MB && p->dlt_count == 0) {
  		p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
  		/*
  		 * If that fails, just leave the list empty.
  		 */
  		if (p->dlt_list != NULL) {
  			p->dlt_list[0] = DLT_EN10MB;
  			p->dlt_list[1] = DLT_DOCSIS;
  			p->dlt_count = 2;
  		}
  	}
  #ifdef PCAP_FDDIPAD
  	if (v == DLT_FDDI)
  		p->fddipad = PCAP_FDDIPAD;
  	else
  #endif
  		p->fddipad = 0;
  	p->linktype = v;
  
  #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT)
  	/*
  	 * Do a BIOCSHDRCMPLT, if defined, to turn that flag on, so
  	 * the link-layer source address isn't forcibly overwritten.
  	 * (Should we ignore errors?  Should we do this only if
  	 * we're open for writing?)
  	 *
  	 * XXX - I seem to remember some packet-sending bug in some
  	 * BSDs - check CVS log for "bpf.c"?
  	 */
  	if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) {
  		(void)pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  		    "BIOCSHDRCMPLT: %s", pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  #endif
  	/* set timeout */
  #ifdef HAVE_ZEROCOPY_BPF
  	/*
  	 * In zero-copy mode, we just use the timeout in select().
  	 * XXX - what if we're in non-blocking mode and the *application*
  	 * is using select() or poll() or kqueues or....?
  	 */
  	if (p->opt.timeout && !pb->zerocopy) {
  #else
  	if (p->opt.timeout) {
  #endif
  		/*
  		 * XXX - is this seconds/nanoseconds in AIX?
  		 * (Treating it as such doesn't fix the timeout
  		 * problem described below.)
  		 *
  		 * XXX - Mac OS X 10.6 mishandles BIOCSRTIMEOUT in
  		 * 64-bit userland - it takes, as an argument, a
  		 * "struct BPF_TIMEVAL", which has 32-bit tv_sec
  		 * and tv_usec, rather than a "struct timeval".
  		 *
  		 * If this platform defines "struct BPF_TIMEVAL",
  		 * we check whether the structure size in BIOCSRTIMEOUT
  		 * is that of a "struct timeval" and, if not, we use
  		 * a "struct BPF_TIMEVAL" rather than a "struct timeval".
  		 * (That way, if the bug is fixed in a future release,
  		 * we will still do the right thing.)
  		 */
  		struct timeval to;
  #ifdef HAVE_STRUCT_BPF_TIMEVAL
  		struct BPF_TIMEVAL bpf_to;
  
  		if (IOCPARM_LEN(BIOCSRTIMEOUT) != sizeof(struct timeval)) {
  			bpf_to.tv_sec = p->opt.timeout / 1000;
  			bpf_to.tv_usec = (p->opt.timeout * 1000) % 1000000;
  			if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&bpf_to) < 0) {
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "BIOCSRTIMEOUT: %s", pcap_strerror(errno));
  				status = PCAP_ERROR;
  				goto bad;
  			}
  		} else {
  #endif
  			to.tv_sec = p->opt.timeout / 1000;
  			to.tv_usec = (p->opt.timeout * 1000) % 1000000;
  			if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) {
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				    "BIOCSRTIMEOUT: %s", pcap_strerror(errno));
  				status = PCAP_ERROR;
  				goto bad;
  			}
  #ifdef HAVE_STRUCT_BPF_TIMEVAL
  		}
  #endif
  	}
  
  #ifdef	BIOCIMMEDIATE
  	/*
  	 * Darren Reed notes that
  	 *
  	 *	On AIX (4.2 at least), if BIOCIMMEDIATE is not set, the
  	 *	timeout appears to be ignored and it waits until the buffer
  	 *	is filled before returning.  The result of not having it
  	 *	set is almost worse than useless if your BPF filter
  	 *	is reducing things to only a few packets (i.e. one every
  	 *	second or so).
  	 *
  	 * so we always turn BIOCIMMEDIATE mode on if this is AIX.
  	 *
  	 * For other platforms, we don't turn immediate mode on by default,
  	 * as that would mean we get woken up for every packet, which
  	 * probably isn't what you want for a packet sniffer.
  	 *
  	 * We set immediate mode if the caller requested it by calling
  	 * pcap_set_immediate() before calling pcap_activate().
  	 */
  #ifndef _AIX
  	if (p->opt.immediate) {
  #endif /* _AIX */
  		v = 1;
  		if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "BIOCIMMEDIATE: %s", pcap_strerror(errno));
  			status = PCAP_ERROR;
  			goto bad;
  		}
  #ifndef _AIX
  	}
  #endif /* _AIX */
  #else /* BIOCIMMEDIATE */
  	if (p->opt.immediate) {
  		/*
  		 * We don't support immediate mode.  Fail.
  		 */
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Immediate mode not supported");
  		status = PCAP_ERROR;
  		goto bad;
  	}
  #endif /* BIOCIMMEDIATE */
  
  	if (p->opt.promisc) {
  		/* set promiscuous mode, just warn if it fails */
  		if (ioctl(p->fd, BIOCPROMISC, NULL) < 0) {
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s",
  			    pcap_strerror(errno));
  			status = PCAP_WARNING_PROMISC_NOTSUP;
  		}
  	}
  
  #ifdef BIOCSTSTAMP
  	v = BPF_T_BINTIME;
  	if (ioctl(p->fd, BIOCSTSTAMP, &v) < 0) {
  		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSTSTAMP: %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  #endif /* BIOCSTSTAMP */
  
  	if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  	p->bufsize = v;
  #ifdef HAVE_ZEROCOPY_BPF
  	if (!pb->zerocopy) {
  #endif
  	p->buffer = malloc(p->bufsize);
  	if (p->buffer == NULL) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  #ifdef _AIX
  	/* For some strange reason this seems to prevent the EFAULT
  	 * problems we have experienced from AIX BPF. */
  	memset(p->buffer, 0x0, p->bufsize);
  #endif
  #ifdef HAVE_ZEROCOPY_BPF
  	}
  #endif
  
  	/*
  	 * If there's no filter program installed, there's
  	 * no indication to the kernel of what the snapshot
  	 * length should be, so no snapshotting is done.
  	 *
  	 * Therefore, when we open the device, we install
  	 * an "accept everything" filter with the specified
  	 * snapshot length.
  	 */
  	total_insn.code = (u_short)(BPF_RET | BPF_K);
  	total_insn.jt = 0;
  	total_insn.jf = 0;
  	total_insn.k = p->snapshot;
  
  	total_prog.bf_len = 1;
  	total_prog.bf_insns = &total_insn;
  	if (ioctl(p->fd, BIOCSETF, (caddr_t)&total_prog) < 0) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
  		    pcap_strerror(errno));
  		status = PCAP_ERROR;
  		goto bad;
  	}
  
  	/*
  	 * On most BPF platforms, either you can do a "select()" or
  	 * "poll()" on a BPF file descriptor and it works correctly,
  	 * or you can do it and it will return "readable" if the
  	 * hold buffer is full but not if the timeout expires *and*
  	 * a non-blocking read will, if the hold buffer is empty
  	 * but the store buffer isn't empty, rotate the buffers
  	 * and return what packets are available.
  	 *
  	 * In the latter case, the fact that a non-blocking read
  	 * will give you the available packets means you can work
  	 * around the failure of "select()" and "poll()" to wake up
  	 * and return "readable" when the timeout expires by using
  	 * the timeout as the "select()" or "poll()" timeout, putting
  	 * the BPF descriptor into non-blocking mode, and read from
  	 * it regardless of whether "select()" reports it as readable
  	 * or not.
  	 *
  	 * However, in FreeBSD 4.3 and 4.4, "select()" and "poll()"
  	 * won't wake up and return "readable" if the timer expires
  	 * and non-blocking reads return EWOULDBLOCK if the hold
  	 * buffer is empty, even if the store buffer is non-empty.
  	 *
  	 * This means the workaround in question won't work.
  	 *
  	 * Therefore, on FreeBSD 4.3 and 4.4, we set "p->selectable_fd"
  	 * to -1, which means "sorry, you can't use 'select()' or 'poll()'
  	 * here".  On all other BPF platforms, we set it to the FD for
  	 * the BPF device; in NetBSD, OpenBSD, and Darwin, a non-blocking
  	 * read will, if the hold buffer is empty and the store buffer
  	 * isn't empty, rotate the buffers and return what packets are
  	 * there (and in sufficiently recent versions of OpenBSD
  	 * "select()" and "poll()" should work correctly).
  	 *
  	 * XXX - what about AIX?
  	 */
  	p->selectable_fd = p->fd;	/* assume select() works until we know otherwise */
  	if (have_osinfo) {
  		/*
  		 * We can check what OS this is.
  		 */
  		if (strcmp(osinfo.sysname, "FreeBSD") == 0) {
  			if (strncmp(osinfo.release, "4.3-", 4) == 0 ||
  			     strncmp(osinfo.release, "4.4-", 4) == 0)
  				p->selectable_fd = -1;
  		}
  	}
  
  	p->read_op = pcap_read_bpf;
  	p->inject_op = pcap_inject_bpf;
  	p->setfilter_op = pcap_setfilter_bpf;
  	p->setdirection_op = pcap_setdirection_bpf;
  	p->set_datalink_op = pcap_set_datalink_bpf;
  	p->getnonblock_op = pcap_getnonblock_bpf;
  	p->setnonblock_op = pcap_setnonblock_bpf;
  	p->stats_op = pcap_stats_bpf;
  	p->cleanup_op = pcap_cleanup_bpf;
  
  	return (status);
   bad:
  	pcap_cleanup_bpf(p);
  	return (status);
  }
  
  /*
   * Not all interfaces can be bound to by BPF, so try to bind to
   * the specified interface; return 0 if we fail with
   * PCAP_ERROR_NO_SUCH_DEVICE (which means we got an ENXIO when we tried
   * to bind, which means this interface isn't in the list of interfaces
   * attached to BPF) and 1 otherwise.
   */
  static int
  check_bpf_bindable(const char *name)
  {
  	int fd;
  	char errbuf[PCAP_ERRBUF_SIZE];
  
  	fd = bpf_open_and_bind(name, errbuf);
  	if (fd < 0) {
  		/*
  		 * Error - was it PCAP_ERROR_NO_SUCH_DEVICE?
  		 */
  		if (fd == PCAP_ERROR_NO_SUCH_DEVICE) {
  			/*
  			 * Yes, so we can't bind to this because it's
  			 * not something supported by BPF.
  			 */
  			return (0);
  		}
  		/*
  		 * No, so we don't know whether it's supported or not;
  		 * say it is, so that the user can at least try to
  		 * open it and report the error (which is probably
  		 * "you don't have permission to open BPF devices";
  		 * reporting those interfaces means users will ask
  		 * "why am I getting a permissions error when I try
  		 * to capture" rather than "why am I not seeing any
  		 * interfaces", making the underlying problem clearer).
  		 */
  		return (1);
  	}
  
  	/*
  	 * Success.
  	 */
  	close(fd);
  	return (1);
  }
  
  #if defined(__FreeBSD__) && defined(SIOCIFCREATE2)
  static int
  finddevs_usb(pcap_if_t **alldevsp, char *errbuf)
  {
  	DIR *usbdir;
  	struct dirent *usbitem;
  	size_t name_max;
  	char *name;
  
  	/*
  	 * We might have USB sniffing support, so try looking for USB
  	 * interfaces.
  	 *
  	 * We want to report a usbusN device for each USB bus, but
  	 * usbusN interfaces might, or might not, exist for them -
  	 * we create one if there isn't already one.
  	 *
  	 * So, instead, we look in /dev/usb for all buses and create
  	 * a "usbusN" device for each one.
  	 */
  	usbdir = opendir("/dev/usb");
  	if (usbdir == NULL) {
  		/*
  		 * Just punt.
  		 */
  		return (0);
  	}
  
  	/*
  	 * Leave enough room for a 32-bit (10-digit) bus number.
  	 * Yes, that's overkill, but we won't be using
  	 * the buffer very long.
  	 */
  	name_max = USBUS_PREFIX_LEN + 10 + 1;
  	name = malloc(name_max);
  	if (name == NULL) {
  		closedir(usbdir);
  		return (0);
  	}
  	while ((usbitem = readdir(usbdir)) != NULL) {
  		char *p;
  		size_t busnumlen;
  		int err;
  
  		if (strcmp(usbitem->d_name, ".") == 0 ||
  		    strcmp(usbitem->d_name, "..") == 0) {
  			/*
  			 * Ignore these.
  			 */
  			continue;
  		}
  		p = strchr(usbitem->d_name, '.');
  		if (p == NULL)
  			continue;
  		busnumlen = p - usbitem->d_name;
  		memcpy(name, usbus_prefix, USBUS_PREFIX_LEN);
  		memcpy(name + USBUS_PREFIX_LEN, usbitem->d_name, busnumlen);
  		*(name + USBUS_PREFIX_LEN + busnumlen) = '\0';
  		err = pcap_add_if(alldevsp, name, PCAP_IF_UP, NULL, errbuf);
  		if (err != 0) {
  			free(name);
  			closedir(usbdir);
  			return (err);
  		}
  	}
  	free(name);
  	closedir(usbdir);
  	return (0);
  }
  #endif
  
  int
  pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
  {
  	/*
  	 * Get the list of regular interfaces first.
  	 */
  	if (pcap_findalldevs_interfaces(alldevsp, errbuf, check_bpf_bindable) == -1)
  		return (-1);	/* failure */
  
  #if defined(__FreeBSD__) && defined(SIOCIFCREATE2)
  	if (finddevs_usb(alldevsp, errbuf) == -1)
  		return (-1);
  #endif
  
  	return (0);
  }
  
  #ifdef HAVE_BSD_IEEE80211
  static int
  monitor_mode(pcap_t *p, int set)
  {
  	struct pcap_bpf *pb = p->priv;
  	int sock;
  	struct ifmediareq req;
  	IFM_ULIST_TYPE *media_list;
  	int i;
  	int can_do;
  	struct ifreq ifr;
  
  	sock = socket(AF_INET, SOCK_DGRAM, 0);
  	if (sock == -1) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "can't open socket: %s",
  		    pcap_strerror(errno));
  		return (PCAP_ERROR);
  	}
  
  	memset(&req, 0, sizeof req);
  	strncpy(req.ifm_name, p->opt.device, sizeof req.ifm_name);
  
  	/*
  	 * Find out how many media types we have.
  	 */
  	if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
  		/*
  		 * Can't get the media types.
  		 */
  		switch (errno) {
  
  		case ENXIO:
  			/*
  			 * There's no such device.
  			 */
  			close(sock);
  			return (PCAP_ERROR_NO_SUCH_DEVICE);
  
  		case EINVAL:
  			/*
  			 * Interface doesn't support SIOC{G,S}IFMEDIA.
  			 */
  			close(sock);
  			return (PCAP_ERROR_RFMON_NOTSUP);
  
  		default:
  			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  			    "SIOCGIFMEDIA 1: %s", pcap_strerror(errno));
  			close(sock);
  			return (PCAP_ERROR);
  		}
  	}
  	if (req.ifm_count == 0) {
  		/*
  		 * No media types.
  		 */
  		close(sock);
  		return (PCAP_ERROR_RFMON_NOTSUP);
  	}
  
  	/*
  	 * Allocate a buffer to hold all the media types, and
  	 * get the media types.
  	 */
  	media_list = malloc(req.ifm_count * sizeof(*media_list));
  	if (media_list == NULL) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s",
  		    pcap_strerror(errno));
  		close(sock);
  		return (PCAP_ERROR);
  	}
  	req.ifm_ulist = media_list;
  	if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA: %s",
  		    pcap_strerror(errno));
  		free(media_list);
  		close(sock);
  		return (PCAP_ERROR);
  	}
  
  	/*
  	 * Look for an 802.11 "automatic" media type.
  	 * We assume that all 802.11 adapters have that media type,
  	 * and that it will carry the monitor mode supported flag.
  	 */
  	can_do = 0;
  	for (i = 0; i < req.ifm_count; i++) {
  		if (IFM_TYPE(media_list[i]) == IFM_IEEE80211
  		    && IFM_SUBTYPE(media_list[i]) == IFM_AUTO) {
  			/* OK, does it do monitor mode? */
  			if (media_list[i] & IFM_IEEE80211_MONITOR) {
  				can_do = 1;
  				break;
  			}
  		}
  	}
  	free(media_list);
  	if (!can_do) {
  		/*
  		 * This adapter doesn't support monitor mode.
  		 */
  		close(sock);
  		return (PCAP_ERROR_RFMON_NOTSUP);
  	}
  
  	if (set) {
  		/*
  		 * Don't just check whether we can enable monitor mode,
  		 * do so, if it's not already enabled.
  		 */
  		if ((req.ifm_current & IFM_IEEE80211_MONITOR) == 0) {
  			/*
  			 * Monitor mode isn't currently on, so turn it on,
  			 * and remember that we should turn it off when the
  			 * pcap_t is closed.
  			 */
  
  			/*
  			 * If we haven't already done so, arrange to have
  			 * "pcap_close_all()" called when we exit.
  			 */
  			if (!pcap_do_addexit(p)) {
  				/*
  				 * "atexit()" failed; don't put the interface
  				 * in monitor mode, just give up.
  				 */
  				close(sock);
  				return (PCAP_ERROR);
  			}
  			memset(&ifr, 0, sizeof(ifr));
  			(void)strncpy(ifr.ifr_name, p->opt.device,
  			    sizeof(ifr.ifr_name));
  			ifr.ifr_media = req.ifm_current | IFM_IEEE80211_MONITOR;
  			if (ioctl(sock, SIOCSIFMEDIA, &ifr) == -1) {
  				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
  				     "SIOCSIFMEDIA: %s", pcap_strerror(errno));
  				close(sock);
  				return (PCAP_ERROR);
  			}
  
  			pb->must_do_on_close |= MUST_CLEAR_RFMON;
  
  			/*
  			 * Add this to the list of pcaps to close when we exit.
  			 */
  			pcap_add_to_pcaps_to_close(p);
  		}
  	}
  	return (0);
  }
  #endif /* HAVE_BSD_IEEE80211 */
  
  #if defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211))
  /*
   * Check whether we have any 802.11 link-layer types; return the best
   * of the 802.11 link-layer types if we find one, and return -1
   * otherwise.
   *
   * DLT_IEEE802_11_RADIO, with the radiotap header, is considered the
   * best 802.11 link-layer type; any of the other 802.11-plus-radio
   * headers are second-best; 802.11 with no radio information is
   * the least good.
   */
  static int
  find_802_11(struct bpf_dltlist *bdlp)
  {
  	int new_dlt;
  	u_int i;
  
  	/*
  	 * Scan the list of DLT_ values, looking for 802.11 values,
  	 * and, if we find any, choose the best of them.
  	 */
  	new_dlt = -1;
  	for (i = 0; i < bdlp->bfl_len; i++) {
  		switch (bdlp->bfl_list[i]) {
  
  		case DLT_IEEE802_11:
  			/*
  			 * 802.11, but no radio.
  			 *
  			 * Offer this, and select it as the new mode
  			 * unless we've already found an 802.11
  			 * header with radio information.
  			 */
  			if (new_dlt == -1)
  				new_dlt = bdlp->bfl_list[i];
  			break;
  
  		case DLT_PRISM_HEADER:
  		case DLT_AIRONET_HEADER:
  		case DLT_IEEE802_11_RADIO_AVS:
  			/*
  			 * 802.11 with radio, but not radiotap.
  			 *
  			 * Offer this, and select it as the new mode
  			 * unless we've already found the radiotap DLT_.
  			 */
  			if (new_dlt != DLT_IEEE802_11_RADIO)
  				new_dlt = bdlp->bfl_list[i];
  			break;
  
  		case DLT_IEEE802_11_RADIO:
  			/*
  			 * 802.11 with radiotap.
  			 *
  			 * Offer this, and select it as the new mode.
  			 */
  			new_dlt = bdlp->bfl_list[i];
  			break;
  
  		default:
  			/*
  			 * Not 802.11.
  			 */
  			break;
  		}
  	}
  
  	return (new_dlt);
  }
  #endif /* defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)) */
  
  #if defined(__APPLE__) && defined(BIOCGDLTLIST)
  /*
   * Remove DLT_EN10MB from the list of DLT_ values, as we're in monitor mode,
   * and DLT_EN10MB isn't supported in monitor mode.
   */
  static void
  remove_en(pcap_t *p)
  {
  	int i, j;
  
  	/*
  	 * Scan the list of DLT_ values and discard DLT_EN10MB.
  	 */
  	j = 0;
  	for (i = 0; i < p->dlt_count; i++) {
  		switch (p->dlt_list[i]) {
  
  		case DLT_EN10MB:
  			/*
  			 * Don't offer this one.
  			 */
  			continue;
  
  		default:
  			/*
  			 * Just copy this mode over.
  			 */
  			break;
  		}
  
  		/*
  		 * Copy this DLT_ value to its new position.
  		 */
  		p->dlt_list[j] = p->dlt_list[i];
  		j++;
  	}
  
  	/*
  	 * Set the DLT_ count to the number of entries we copied.
  	 */
  	p->dlt_count = j;
  }
  
  /*
   * Remove 802.11 link-layer types from the list of DLT_ values, as
   * we're not in monitor mode, and those DLT_ values will switch us
   * to monitor mode.
   */
  static void
  remove_802_11(pcap_t *p)
  {
  	int i, j;
  
  	/*
  	 * Scan the list of DLT_ values and discard 802.11 values.
  	 */
  	j = 0;
  	for (i = 0; i < p->dlt_count; i++) {
  		switch (p->dlt_list[i]) {
  
  		case DLT_IEEE802_11:
  		case DLT_PRISM_HEADER:
  		case DLT_AIRONET_HEADER:
  		case DLT_IEEE802_11_RADIO:
  		case DLT_IEEE802_11_RADIO_AVS:
  			/*
  			 * 802.11.  Don't offer this one.
  			 */
  			continue;
  
  		default:
  			/*
  			 * Just copy this mode over.
  			 */
  			break;
  		}
  
  		/*
  		 * Copy this DLT_ value to its new position.
  		 */
  		p->dlt_list[j] = p->dlt_list[i];
  		j++;
  	}
  
  	/*
  	 * Set the DLT_ count to the number of entries we copied.
  	 */
  	p->dlt_count = j;
  }
  #endif /* defined(__APPLE__) && defined(BIOCGDLTLIST) */
  
  static int
  pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp)
  {
  	struct pcap_bpf *pb = p->priv;
  
  	/*
  	 * Free any user-mode filter we might happen to have installed.
  	 */
  	pcap_freecode(&p->fcode);
  
  	/*
  	 * Try to install the kernel filter.
  	 */
  	if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) == 0) {
  		/*
  		 * It worked.
  		 */
  		pb->filtering_in_kernel = 1;	/* filtering in the kernel */
  
  		/*
  		 * Discard any previously-received packets, as they might
  		 * have passed whatever filter was formerly in effect, but
  		 * might not pass this filter (BIOCSETF discards packets
  		 * buffered in the kernel, so you can lose packets in any
  		 * case).
  		 */
  		p->cc = 0;
  		return (0);
  	}
  
  	/*
  	 * We failed.
  	 *
  	 * If it failed with EINVAL, that's probably because the program
  	 * is invalid or too big.  Validate it ourselves; if we like it
  	 * (we currently allow backward branches, to support protochain),
  	 * run it in userland.  (There's no notion of "too big" for
  	 * userland.)
  	 *
  	 * Otherwise, just give up.
  	 * XXX - if the copy of the program into the kernel failed,
  	 * we will get EINVAL rather than, say, EFAULT on at least
  	 * some kernels.
  	 */
  	if (errno != EINVAL) {
  		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
  		    pcap_strerror(errno));
  		return (-1);
  	}
  
  	/*
  	 * install_bpf_program() validates the program.
  	 *
  	 * XXX - what if we already have a filter in the kernel?
  	 */
  	if (install_bpf_program(p, fp) < 0)
  		return (-1);
  	pb->filtering_in_kernel = 0;	/* filtering in userland */
  	return (0);
  }
  
  /*
   * Set direction flag: Which packets do we accept on a forwarding
   * single device? IN, OUT or both?
   */
  static int
  pcap_setdirection_bpf(pcap_t *p, pcap_direction_t d)
  {
  #if defined(BIOCSDIRECTION)
  	u_int direction;
  
  	direction = (d == PCAP_D_IN) ? BPF_D_IN :
  	    ((d == PCAP_D_OUT) ? BPF_D_OUT : BPF_D_INOUT);
  	if (ioctl(p->fd, BIOCSDIRECTION, &direction) == -1) {
  		(void) pcap_snprintf(p->errbuf, sizeof(p->errbuf),
  		    "Cannot set direction to %s: %s",
  		        (d == PCAP_D_IN) ? "PCAP_D_IN" :
  			((d == PCAP_D_OUT) ? "PCAP_D_OUT" : "PCAP_D_INOUT"),
  			strerror(errno));
  		return (-1);
  	}
  	return (0);
  #elif defined(BIOCSSEESENT)
  	u_int seesent;
  
  	/*
  	 * We don't support PCAP_D_OUT.
  	 */
  	if (d == PCAP_D_OUT) {
  		pcap_snprintf(p->errbuf, sizeof(p->errbuf),
  		    "Setting direction to PCAP_D_OUT is not supported on BPF");
  		return -1;
  	}
  
  	seesent = (d == PCAP_D_INOUT);
  	if (ioctl(p->fd, BIOCSSEESENT, &seesent) == -1) {
  		(void) pcap_snprintf(p->errbuf, sizeof(p->errbuf),
  		    "Cannot set direction to %s: %s",
  		        (d == PCAP_D_INOUT) ? "PCAP_D_INOUT" : "PCAP_D_IN",
  			strerror(errno));
  		return (-1);
  	}
  	return (0);
  #else
  	(void) pcap_snprintf(p->errbuf, sizeof(p->errbuf),
  	    "This system doesn't support BIOCSSEESENT, so the direction can't be set");
  	return (-1);
  #endif
  }
  
  static int
  pcap_set_datalink_bpf(pcap_t *p, int dlt)
  {
  #ifdef BIOCSDLT
  	if (ioctl(p->fd, BIOCSDLT, &dlt) == -1) {
  		(void) pcap_snprintf(p->errbuf, sizeof(p->errbuf),
  		    "Cannot set DLT %d: %s", dlt, strerror(errno));
  		return (-1);
  	}
  #endif
  	return (0);
  }
  