Merge remote-tracking branch 'goog/tcpdump'

* goog/tcpdump: (1872 commits)
  Remove old version. Getting ready for new libpcap 1.5
  Remove commas from clauses in a comma-separated list.
  Fix typo.
  Describe all NFLOG TLV types and define structures for some of them.
  Check caplen in the NFLOG TLV loop.
  Have nflog_tlv_t include only the TLV header.
  Byte-swap the T and L in TLVs as necessary when reading an NFLOG file.
  Don't support D-Bus sniffing on OS X.
  Add post-1.5.2 bug fixes.
  Tag some changes with a bug identifier.
  Add items for 1.5.1 and 1.5.2.
  Formatting tweak.
  Count *ring buffer blocks*, not *packets* to be filtered in userland.
  Add a PACKET_COUNT_IS_UNLIMITED() to test for a packet count <= 0.
  Use HAVE_TPACKET3 rather than TPACKET_V3 to test for TPACKET_V3 support.
  Fix builds on systems without TPACKET_V3.
  tweak manpages formatting
  Fix pcap_loop() with a count of 0 and TPACKET_V3.
  Discourage the use of a zero timeout.
  We can't use TPACKET_V3 in immediate mode, so fall back on TPACKET_V2.
  ...

Change-Id: I2aa9bd87673c56aee439e1154b96a14026ca7985
diff --git a/pcap-bpf.c b/pcap-bpf.c
index 027913e..250298a 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -20,7 +20,7 @@
  */
 #ifndef lint
 static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.86.2.12 2007/06/15 17:57:27 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.116 2008-09-16 18:42:29 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -28,19 +28,40 @@
 #endif
 
 #include <sys/param.h>			/* optionally get BSD define */
-#include <sys/time.h>
-#include <sys/timeb.h>
+#ifdef HAVE_ZEROCOPY_BPF
+#include <sys/mman.h>
+#endif
 #include <sys/socket.h>
-#include <sys/file.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>
 
+#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
+ * 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
@@ -78,6 +99,8 @@
 static int bpfloadedflag = 0;
 static int odmlockid = 0;
 
+static int bpf_load(char *errbuf);
+
 #else /* _AIX */
 
 #include <net/bpf.h>
@@ -85,6 +108,7 @@
 #endif /* _AIX */
 
 #include <ctype.h>
+#include <fcntl.h>
 #include <errno.h>
 #include <netdb.h>
 #include <stdio.h>
@@ -92,22 +116,680 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "pcap-int.h"
+#ifdef HAVE_NET_IF_MEDIA_H
+# include <net/if_media.h>
+#endif
 
-#ifdef HAVE_DAG_API
-#include "pcap-dag.h"
-#endif /* HAVE_DAG_API */
+#include "pcap-int.h"
 
 #ifdef HAVE_OS_PROTO_H
 #include "os-proto.h"
 #endif
 
-#include "gencode.h"	/* for "no_optimize" */
+/*
+ * 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 PCAP_FDDIPAD
+	int fddipad;
+#endif
+
+#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 */
+
+#ifdef BIOCGDLTLIST
+# if (defined(HAVE_NET_IF_MEDIA_H) && defined(IFM_IEEE80211)) && !defined(__APPLE__)
+#define HAVE_BSD_IEEE80211
+# 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) 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) 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) 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, char *ebuf)
+{
+	pcap_t *p;
+
+	p = pcap_create_common(device, 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;
+	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(pcap_t *p)
+{
+	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(p->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;
+		snprintf(p->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)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.
+				 */
+				snprintf(p->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.
+				 */
+				snprintf(p->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;
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			    "(cannot open BPF device) %s: %s", device,
+			    pcap_strerror(errno));
+			break;
+
+		default:
+			/*
+			 * Some other problem.
+			 */
+			fd = PCAP_ERROR;
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			    "(cannot open BPF device) %s: %s", device,
+			    pcap_strerror(errno));
+			break;
+		}
+	}
+#endif
+
+	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)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
+			    pcap_strerror(errno));
+			return (PCAP_ERROR);
+		}
+
+		if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) < 0) {
+			(void)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)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.source, "en", 2) != 0) {
+			/*
+			 * Not an enN device; no monitor mode.
+			 */
+			return (0);
+		}
+		fd = socket(AF_INET, SOCK_DGRAM, 0);
+		if (fd == -1) {
+			(void)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.source + 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);
+	if (fd < 0)
+		return (fd);	/* fd is the appropriate error code */
+
+	/*
+	 * Now bind to the device.
+	 */
+	(void)strncpy(ifr.ifr_name, p->opt.source, 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:
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			    "BIOCSETIF: %s: %s",
+			    p->opt.source, 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);
+#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)
 {
@@ -129,27 +811,30 @@
 	if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) {
 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s",
 		    pcap_strerror(errno));
-		return (-1);
+		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;
-	struct bpf_insn *fcode;
 #ifdef PCAP_FDDIPAD
 	register int pad;
 #endif
+#ifdef HAVE_ZEROCOPY_BPF
+	int i;
+#endif
 
-	fcode = p->md.use_bpf ? NULL : p->fcode.bf_insns;
  again:
 	/*
 	 * Has "pcap_breakloop()" been called?
@@ -157,15 +842,36 @@
 	if (p->break_loop) {
 		/*
 		 * Yes - clear the flag that indicates that it
-		 * has, and return -2 to indicate that we were
-		 * told to break out of the loop.
+		 * has, and return PCAP_ERROR_BREAK to indicate
+		 * that we were told to break out of the loop.
 		 */
 		p->break_loop = 0;
-		return (-2);
+		return (PCAP_ERROR_BREAK);
 	}
 	cc = p->cc;
 	if (p->cc == 0) {
-		cc = read(p->fd, (char *)p->buffer, p->bufsize);
+		/*
+		 * 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, (char *)p->buffer, p->bufsize);
+		}
 		if (cc < 0) {
 			/* Don't choke when we get ptraced */
 			switch (errno) {
@@ -180,16 +886,16 @@
 				 *
 				 * For some unknown reason the uiomove()
 				 * operation in the bpf kernel extension
-				 * used to copy the buffer into user 
+				 * 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. 
+				 * 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 
+				 * 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
@@ -197,11 +903,26 @@
 				 * we just ignore EFAULT and keep reading.
 				 */
 				goto again;
-#endif 
-  
+#endif
+
 			case EWOULDBLOCK:
 				return (0);
-#if defined(sun) && !defined(BSD)
+
+			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.
+				 */
+				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.
@@ -218,7 +939,7 @@
 			}
 			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s",
 			    pcap_strerror(errno));
-			return (-1);
+			return (PCAP_ERROR);
 		}
 		bp = p->buffer;
 	} else
@@ -238,21 +959,36 @@
 		/*
 		 * Has "pcap_breakloop()" been called?
 		 * If so, return immediately - if we haven't read any
-		 * packets, clear the flag and return -2 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.
+		 * 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 (-2);
-			} else {
-				p->bp = bp;
-				p->cc = ep - bp;
+				return (PCAP_ERROR_BREAK);
+			} else
 				return (n);
-			}
 		}
 
 		caplen = bhp->bh_caplen;
@@ -260,7 +996,8 @@
 		datap = bp + hdrlen;
 		/*
 		 * Short-circuit evaluation: if using BPF filter
-		 * in kernel, no need to do it now.
+		 * 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
@@ -270,8 +1007,8 @@
 		 * skipping that padding.
 #endif
 		 */
-		if (fcode == NULL ||
-		    bpf_filter(fcode, datap, bhp->bh_datalen, caplen)) {
+		if (pb->filtering_in_kernel ||
+		    bpf_filter(p->fcode.bf_insns, datap, bhp->bh_datalen, caplen)) {
 			struct pcap_pkthdr pkthdr;
 
 			pkthdr.ts.tv_sec = bhp->bh_tstamp.tv_sec;
@@ -300,9 +1037,14 @@
 #endif
 			(*callback)(user, &pkthdr, datap);
 			bp += BPF_WORDALIGN(caplen + hdrlen);
-			if (++n >= cnt && cnt > 0) {
+			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 {
@@ -349,7 +1091,7 @@
 			(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 			    "send: can't turn off BIOCSHDRCMPLT: %s",
 			    pcap_strerror(errno));
-			return (-1);
+			return (PCAP_ERROR);
 		}
 
 		/*
@@ -361,13 +1103,13 @@
 	if (ret == -1) {
 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 		    pcap_strerror(errno));
-		return (-1);
+		return (PCAP_ERROR);
 	}
 	return (ret);
 }
 
 #ifdef _AIX
-static int 
+static int
 bpf_odminit(char *errbuf)
 {
 	char *errstr;
@@ -378,7 +1120,7 @@
 		snprintf(errbuf, PCAP_ERRBUF_SIZE,
 		    "bpf_load: odm_initialize failed: %s",
 		    errstr);
-		return (-1);
+		return (PCAP_ERROR);
 	}
 
 	if ((odmlockid = odm_lock("/etc/objrepos/config_lock", ODM_WAIT)) == -1) {
@@ -387,33 +1129,38 @@
 		snprintf(errbuf, PCAP_ERRBUF_SIZE,
 		    "bpf_load: odm_lock of /etc/objrepos/config_lock failed: %s",
 		    errstr);
-		return (-1);
+		(void)odm_terminate();
+		return (PCAP_ERROR);
 	}
 
 	return (0);
 }
 
-static int 
+static int
 bpf_odmcleanup(char *errbuf)
 {
 	char *errstr;
 
 	if (odm_unlock(odmlockid) == -1) {
-		if (odm_err_msg(odmerrno, &errstr) == -1)
-			errstr = "Unknown error";
-		snprintf(errbuf, PCAP_ERRBUF_SIZE,
-		    "bpf_load: odm_unlock failed: %s",
-		    errstr);
-		return (-1);
+		if (errbuf != NULL) {
+			if (odm_err_msg(odmerrno, &errstr) == -1)
+				errstr = "Unknown error";
+			snprintf(errbuf, PCAP_ERRBUF_SIZE,
+			    "bpf_load: odm_unlock failed: %s",
+			    errstr);
+		}
+		return (PCAP_ERROR);
 	}
 
 	if (odm_terminate() == -1) {
-		if (odm_err_msg(odmerrno, &errstr) == -1)
-			errstr = "Unknown error";
-		snprintf(errbuf, PCAP_ERRBUF_SIZE,
-		    "bpf_load: odm_terminate failed: %s",
-		    errstr);
-		return (-1);
+		if (errbuf != NULL) {
+			if (odm_err_msg(odmerrno, &errstr) == -1)
+				errstr = "Unknown error";
+			snprintf(errbuf, PCAP_ERRBUF_SIZE,
+			    "bpf_load: odm_terminate failed: %s",
+			    errstr);
+		}
+		return (PCAP_ERROR);
 	}
 
 	return (0);
@@ -438,14 +1185,15 @@
 	if (bpfloadedflag)
 		return (0);
 
-	if (bpf_odminit(errbuf) != 0)
-		return (-1);
+	if (bpf_odminit(errbuf) == PCAP_ERROR)
+		return (PCAP_ERROR);
 
 	major = genmajor(BPF_NAME);
 	if (major == -1) {
 		snprintf(errbuf, PCAP_ERRBUF_SIZE,
 		    "bpf_load: genmajor failed: %s", pcap_strerror(errno));
-		return (-1);
+		(void)bpf_odmcleanup(NULL);
+		return (PCAP_ERROR);
 	}
 
 	minors = getminor(major, &numminors, BPF_NAME);
@@ -455,19 +1203,20 @@
 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
 			    "bpf_load: genminor failed: %s",
 			    pcap_strerror(errno));
-			return (-1);
+			(void)bpf_odmcleanup(NULL);
+			return (PCAP_ERROR);
 		}
 	}
 
-	if (bpf_odmcleanup(errbuf))
-		return (-1);
+	if (bpf_odmcleanup(errbuf) == PCAP_ERROR)
+		return (PCAP_ERROR);
 
 	rc = stat(BPF_NODE "0", &sbuf);
 	if (rc == -1 && errno != ENOENT) {
 		snprintf(errbuf, PCAP_ERRBUF_SIZE,
 		    "bpf_load: can't stat %s: %s",
 		    BPF_NODE "0", pcap_strerror(errno));
-		return (-1);
+		return (PCAP_ERROR);
 	}
 
 	if (rc == -1 || getmajor(sbuf.st_rdev) != major) {
@@ -478,7 +1227,7 @@
 				snprintf(errbuf, PCAP_ERRBUF_SIZE,
 				    "bpf_load: can't mknod %s: %s",
 				    buf, pcap_strerror(errno));
-				return (-1);
+				return (PCAP_ERROR);
 			}
 		}
 	}
@@ -494,7 +1243,7 @@
 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
 			    "bpf_load: could not load driver: %s",
 			    strerror(errno));
-			return (-1);
+			return (PCAP_ERROR);
 		}
 	}
 
@@ -502,190 +1251,570 @@
 	cfg_km.cmd = CFG_INIT;
 	cfg_km.kmid = cfg_ld.kmid;
 	cfg_km.mdilen = sizeof(cfg_bpf);
-	cfg_km.mdiptr = (void *)&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) {
 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
 			    "bpf_load: could not configure driver: %s",
 			    strerror(errno));
-			return (-1);
+			return (PCAP_ERROR);
 		}
 	}
-	
+
 	bpfloadedflag = 1;
 
 	return (0);
 }
 #endif
 
-static inline int
-bpf_open(pcap_t *p, char *errbuf)
+/*
+ * Turn off rfmon mode if necessary.
+ */
+static void
+pcap_cleanup_bpf(pcap_t *p)
 {
-	int fd;
-#ifdef HAVE_CLONING_BPF
-	static const char device[] = "/dev/bpf";
-#else
-	int n = 0;
-	char device[sizeof "/dev/bpf0000000000"];
+	struct pcap_bpf *pb = p->priv;
+#ifdef HAVE_BSD_IEEE80211
+	int sock;
+	struct ifmediareq req;
+	struct ifreq ifr;
 #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) == -1)
-		return (-1);
-#endif
-
-#ifdef HAVE_CLONING_BPF
-	if ((fd = open(device, O_RDWR)) == -1 &&
-	    (errno != EACCES || (fd = open(device, O_RDONLY)) == -1))
-		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)snprintf(device, sizeof(device), "/dev/bpf%d", n++);
+	if (pb->must_do_on_close != 0) {
 		/*
-		 * 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.
+		 * There's something we have to do when closing this
+		 * pcap_t.
 		 */
-		fd = open(device, O_RDWR);
-		if (fd == -1 && errno == EACCES)
-			fd = open(device, O_RDONLY);
-	} while (fd < 0 && errno == EBUSY);
+#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 */
 
-	/*
-	 * XXX better message for all minors used
-	 */
-	if (fd < 0)
-		snprintf(errbuf, PCAP_ERRBUF_SIZE, "(no devices found) %s: %s",
-		    device, pcap_strerror(errno));
+		/*
+		 * 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
 
-	return (fd);
+	if (error == ENXIO) {
+		/*
+		 * No such device exists.
+		 */
+#ifdef __APPLE__
+		if (p->opt.rfmon && strncmp(p->opt.source, "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.source + 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;
+					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;
+				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+				    "socket() failed: %s",
+				    pcap_strerror(errno));
+			}
+			return (err);
+		}
+#endif
+		/*
+		 * No such device.
+		 */
+		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.
+		 */
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
+		    p->opt.source, pcap_strerror(errno));
+		return (PCAP_ERROR);
+	}
 }
 
 /*
- * We include the OS's <net/bpf.h>, not our "pcap-bpf.h", so we probably
- * don't get DLT_DOCSIS defined.
+ * 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.
  */
-#ifndef DLT_DOCSIS
-#define DLT_DOCSIS	143
+#ifdef _AIX
+#define DEFAULT_BUFSIZE	32768
+#else
+#define DEFAULT_BUFSIZE	524288
 #endif
 
-pcap_t *
-pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
-    char *ebuf)
+static int
+pcap_activate_bpf(pcap_t *p)
 {
+	struct pcap_bpf *pb = p->priv;
+	int status = 0;
 	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;
-	pcap_t *p;
 	struct bpf_insn total_insn;
 	struct bpf_program total_prog;
 	struct utsname osinfo;
-
-#ifdef HAVE_DAG_API
-	if (strstr(device, "dag")) {
-		return dag_open_live(device, snaplen, promisc, to_ms, ebuf);
-	}
-#endif /* HAVE_DAG_API */
-
-#ifdef BIOCGDLTLIST
-	memset(&bdl, 0, sizeof(bdl));
+	int have_osinfo = 0;
+#ifdef HAVE_ZEROCOPY_BPF
+	struct bpf_zbuf bz;
+	u_int bufmode, zbufmax;
 #endif
 
-	p = (pcap_t *)malloc(sizeof(*p));
-	if (p == NULL) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
-		    pcap_strerror(errno));
-		return (NULL);
-	}
-	memset(p, 0, sizeof(*p));
-	fd = bpf_open(p, ebuf);
-	if (fd < 0)
+	fd = bpf_open(p);
+	if (fd < 0) {
+		status = fd;
 		goto bad;
+	}
 
 	p->fd = fd;
-	p->snapshot = snaplen;
 
 	if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s",
+		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) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE,
+		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)
+	/*
+	 * Check if the given source network device has a '/' separated
+	 * zonename prefix string. The zonename prefixed source device
+	 * can be used by libpcap consumers to capture network traffic
+	 * in non-global zones from the global zone on Solaris 11 and
+	 * above. If the zonename prefix is present then we strip the
+	 * prefix and pass the zone ID as part of lifr_zoneid.
+	 */
+	if ((zonesep = strchr(p->opt.source, '/')) != NULL) {
+		char zonename[ZONENAME_MAX];
+		int  znamelen;
+		char *lnamep;
+
+		znamelen = zonesep - p->opt.source;
+		(void) strlcpy(zonename, p->opt.source, znamelen + 1);
+		lnamep = strdup(zonesep + 1);
+		ifr.lifr_zoneid = getzoneidbyname(zonename);
+		free(p->opt.source);
+		p->opt.source = lnamep;
+	}
+#endif
+
+	pb->device = strdup(p->opt.source);
+	if (pb->device == NULL) {
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
+		     pcap_strerror(errno));
+		status = PCAP_ERROR;
 		goto bad;
 	}
 
 	/*
-	 * Try finding a good size for the buffer; 32768 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.
-	 *
-	 * XXX - there should be a user-accessible hook to set the
-	 * initial buffer size.
+	 * Attempt to find out the version of the OS on which we're running.
 	 */
-	if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || v < 32768)
-		v = 32768;
-	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);
+	if (uname(&osinfo) == 0)
+		have_osinfo = 1;
 
-		(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
-		if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0)
-			break;	/* that size worked; we're done */
-
-		if (errno != ENOBUFS) {
-			snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
-			    device, pcap_strerror(errno));
-			goto bad;
+#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.source, "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.source, 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;
+							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;
+						snprintf(p->errbuf,
+						    PCAP_ERRBUF_SIZE,
+						    "socket() failed: %s",
+						    pcap_strerror(errno));
+					}
+					goto bad;
+				}
+				wltdev = malloc(strlen(p->opt.source) + 2);
+				if (wltdev == NULL) {
+					(void)snprintf(p->errbuf,
+					    PCAP_ERRBUF_SIZE, "malloc: %s",
+					    pcap_strerror(errno));
+					status = PCAP_ERROR;
+					goto bad;
+				}
+				strcpy(wltdev, "wlt");
+				strcat(wltdev, p->opt.source + 2);
+				free(p->opt.source);
+				p->opt.source = wltdev;
+			}
+			/*
+			 * Everything else is 10.5 or later; for those,
+			 * we just open the enN device, and set the DLT.
+			 */
 		}
 	}
+#endif /* __APPLE__ */
+#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;
 
-	if (v == 0) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE,
-			 "BIOCSBLEN: %s: No buffer size worked", device);
-		goto bad;
+		/*
+		 * 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) {
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGETZMAX: %s",
+			    pcap_strerror(errno));
+			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) {
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "mmap: %s",
+			    pcap_strerror(errno));
+			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) {
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETZBUF: %s",
+			    pcap_strerror(errno));
+			goto bad;
+		}
+		(void)strncpy(ifrname, p->opt.source, ifnamsiz);
+		if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
+			    p->opt.source, pcap_strerror(errno));
+			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) {
+				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+				    "BIOCSBLEN: %s: %s", p->opt.source,
+				    pcap_strerror(errno));
+				status = PCAP_ERROR;
+				goto bad;
+			}
+
+			/*
+			 * Now bind to the device.
+			 */
+			(void)strncpy(ifrname, p->opt.source, 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.source, 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) {
+				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+				    "BIOCSBLEN: %s: No buffer size worked",
+				    p->opt.source);
+				status = PCAP_ERROR;
+				goto bad;
+			}
+		}
 	}
 
 	/* Get the data link layer type. */
 	if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s",
+		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.
@@ -713,8 +1842,9 @@
 		/*
 		 * We don't know what to map this to yet.
 		 */
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "unknown interface type %u",
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown interface type %u",
 		    v);
+		status = PCAP_ERROR;
 		goto bad;
 	}
 #endif
@@ -739,13 +1869,6 @@
 		break;
 	}
 #endif
-#ifdef PCAP_FDDIPAD
-	if (v == DLT_FDDI)
-		p->fddipad = PCAP_FDDIPAD;
-	else
-		p->fddipad = 0;
-#endif
-	p->linktype = v;
 
 #ifdef BIOCGDLTLIST
 	/*
@@ -753,68 +1876,144 @@
 	 * this interface supports.  If this fails with EINVAL, it's
 	 * not fatal; we just don't get to use the feature later.
 	 */
-	if (ioctl(fd, BIOCGDLTLIST, (caddr_t)&bdl) == 0) {
-		u_int i;
-		int is_ethernet;
+	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;
 
-		bdl.bfl_list = (u_int *) malloc(sizeof(u_int) * (bdl.bfl_len + 1));
-		if (bdl.bfl_list == NULL) {
-			(void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
-			    pcap_strerror(errno));
-			goto bad;
+#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 (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;
+				}
+			}
 		}
-
-		if (ioctl(fd, BIOCGDLTLIST, (caddr_t)&bdl) < 0) {
-			(void)snprintf(ebuf, PCAP_ERRBUF_SIZE,
-			    "BIOCGDLTLIST: %s", pcap_strerror(errno));
-			free(bdl.bfl_list);
+	}
+#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.
+		 */
+		status = monitor_mode(p, 1);
+		if (status != 0) {
+			/*
+			 * We failed.
+			 */
 			goto bad;
 		}
 
 		/*
-		 * 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).
+		 * 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.
 		 */
-		if (p->linktype == DLT_EN10MB) {
-			is_ethernet = 1;
-			for (i = 0; i < bdl.bfl_len; i++) {
-				if (bdl.bfl_list[i] != DLT_EN10MB) {
-					is_ethernet = 0;
-					break;
+		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 (new_dlt != v) {
+				if (ioctl(p->fd, BIOCSDLT, &new_dlt) != -1) {
+					/*
+					 * We succeeded; make this the
+					 * new DLT_ value.
+					 */
+					v = new_dlt;
 				}
 			}
-			if (is_ethernet) {
-				/*
-				 * We reserved one more slot at the end of
-				 * the list.
-				 */
-				bdl.bfl_list[bdl.bfl_len] = DLT_DOCSIS;
-				bdl.bfl_len++;
-			}
-		}
-		p->dlt_count = bdl.bfl_len;
-		p->dlt_list = bdl.bfl_list;
-	} else {
-		if (errno != EINVAL) {
-			(void)snprintf(ebuf, PCAP_ERRBUF_SIZE,
-			    "BIOCGDLTLIST: %s", pcap_strerror(errno));
-			goto bad;
 		}
 	}
-#endif
+#endif /* various platforms */
+#endif /* BIOCGDLTLIST */
 
 	/*
 	 * If this is an Ethernet device, and we don't have a DLT_ list,
@@ -824,7 +2023,7 @@
 	 * some other way of determining whether it's an Ethernet or 802.11
 	 * device.)
 	 */
-	if (p->linktype == DLT_EN10MB && p->dlt_count == 0) {
+	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.
@@ -835,7 +2034,14 @@
 			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
@@ -847,29 +2053,68 @@
 	 * BSDs - check CVS log for "bpf.c"?
 	 */
 	if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) {
-		(void)snprintf(ebuf, PCAP_ERRBUF_SIZE,
+		(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 		    "BIOCSHDRCMPLT: %s", pcap_strerror(errno));
+		status = PCAP_ERROR;
 		goto bad;
 	}
 #endif
 	/* set timeout */
-	if (to_ms != 0) {
+#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;
-		to.tv_sec = to_ms / 1000;
-		to.tv_usec = (to_ms * 1000) % 1000000;
-		if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) {
-			snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSRTIMEOUT: %s",
-			    pcap_strerror(errno));
-			goto bad;
+#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) {
+				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) {
+				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+				    "BIOCSRTIMEOUT: %s", pcap_strerror(errno));
+				status = PCAP_ERROR;
+				goto bad;
+			}
+#ifdef HAVE_STRUCT_BPF_TIMEVAL
 		}
+#endif
 	}
 
-#ifdef _AIX
 #ifdef	BIOCIMMEDIATE
 	/*
 	 * Darren Reed notes that
@@ -881,76 +2126,73 @@
 	 *	is reducing things to only a few packets (i.e. one every
 	 *	second or so).
 	 *
-	 * so we turn BIOCIMMEDIATE mode on if this is AIX.
+	 * so we always turn BIOCIMMEDIATE mode on if this is AIX.
 	 *
-	 * We don't turn it on for other platforms, as that means we
-	 * get woken up for every packet, which may not be what we want;
-	 * in the Winter 1993 USENIX paper on BPF, they say:
+	 * 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.
 	 *
-	 *	Since a process might want to look at every packet on a
-	 *	network and the time between packets can be only a few
-	 *	microseconds, it is not possible to do a read system call
-	 *	per packet and BPF must collect the data from several
-	 *	packets and return it as a unit when the monitoring
-	 *	application does a read.
-	 *
-	 * which I infer is the reason for the timeout - it means we
-	 * wait that amount of time, in the hopes that more packets
-	 * will arrive and we'll get them all with one read.
-	 *
-	 * Setting BIOCIMMEDIATE mode on FreeBSD (and probably other
-	 * BSDs) causes the timeout to be ignored.
-	 *
-	 * On the other hand, some platforms (e.g., Linux) don't support
-	 * timeouts, they just hand stuff to you as soon as it arrives;
-	 * if that doesn't cause a problem on those platforms, it may
-	 * be OK to have BIOCIMMEDIATE mode on BSD as well.
-	 *
-	 * (Note, though, that applications may depend on the read
-	 * completing, even if no packets have arrived, when the timeout
-	 * expires, e.g. GUI applications that have to check for input
-	 * while waiting for packets to arrive; a non-zero timeout
-	 * prevents "select()" from working right on FreeBSD and
-	 * possibly other BSDs, as the timer doesn't start until a
-	 * "read()" is done, so the timer isn't in effect if the
-	 * application is blocked on a "select()", and the "select()"
-	 * doesn't get woken up for a BPF device until the buffer
-	 * fills up.)
+	 * We set immediate mode if the caller requested it by calling
+	 * pcap_set_immediate() before calling pcap_activate().
 	 */
-	v = 1;
-	if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCIMMEDIATE: %s",
-		    pcap_strerror(errno));
+#ifndef _AIX
+	if (p->opt.immediate) {
+#endif /* _AIX */
+		v = 1;
+		if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) {
+			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.
+		 */
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Immediate mode not supported");
+		status = PCAP_ERROR;
 		goto bad;
 	}
-#endif	/* BIOCIMMEDIATE */
-#endif	/* _AIX */
+#endif /* BIOCIMMEDIATE */
 
-	if (promisc) {
-		/* set promiscuous mode, okay if it fails */
+	if (p->opt.promisc) {
+		/* set promiscuous mode, just warn if it fails */
 		if (ioctl(p->fd, BIOCPROMISC, NULL) < 0) {
-			snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s",
+			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s",
 			    pcap_strerror(errno));
+			status = PCAP_WARNING_PROMISC_NOTSUP;
 		}
 	}
 
 	if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s",
+		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 = (u_char *)malloc(p->bufsize);
 	if (p->buffer == NULL) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
+		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 
+	/* 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
@@ -964,13 +2206,14 @@
 	total_insn.code = (u_short)(BPF_RET | BPF_K);
 	total_insn.jt = 0;
 	total_insn.jf = 0;
-	total_insn.k = snaplen;
+	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) {
-		snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
 		    pcap_strerror(errno));
+		status = PCAP_ERROR;
 		goto bad;
 	}
 
@@ -1011,7 +2254,7 @@
 	 * XXX - what about AIX?
 	 */
 	p->selectable_fd = p->fd;	/* assume select() works until we know otherwise */
-	if (uname(&osinfo) == 0) {
+	if (have_osinfo) {
 		/*
 		 * We can check what OS this is.
 		 */
@@ -1027,48 +2270,343 @@
 	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_fd;
-	p->setnonblock_op = pcap_setnonblock_fd;
+	p->getnonblock_op = pcap_getnonblock_bpf;
+	p->setnonblock_op = pcap_setnonblock_bpf;
 	p->stats_op = pcap_stats_bpf;
-	p->close_op = pcap_close_common;
+	p->cleanup_op = pcap_cleanup_bpf;
 
-	return (p);
+	return (status);
  bad:
-	(void)close(fd);
-	if (p->dlt_list != NULL)
-		free(p->dlt_list);
-	free(p);
-	return (NULL);
+	pcap_cleanup_bpf(p);
+	return (status);
 }
 
 int
 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 {
-#ifdef HAVE_DAG_API
-	if (dag_platform_finddevs(alldevsp, errbuf) < 0)
-		return (-1);
-#endif /* HAVE_DAG_API */
-
 	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;
+	int *media_list;
+	int i;
+	int can_do;
+	struct ifreq ifr;
+
+	sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sock == -1) {
+		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.source, 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:
+			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(int));
+	if (media_list == NULL) {
+		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) {
+		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.
+				 */
+				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+				     "atexit failed");
+				close(sock);
+				return (PCAP_ERROR);
+			}
+			memset(&ifr, 0, sizeof(ifr));
+			(void)strncpy(ifr.ifr_name, p->opt.source,
+			    sizeof(ifr.ifr_name));
+			ifr.ifr_media = req.ifm_current | IFM_IEEE80211_MONITOR;
+			if (ioctl(sock, SIOCSIFMEDIA, &ifr) == -1) {
+				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;
+	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)
 {
-	/*
-	 * It looks that BPF code generated by gen_protochain() is not
-	 * compatible with some of kernel BPF code (for example BSD/OS 3.1).
-	 * Take a safer side for now.
-	 */
-	if (no_optimize) {
-		/*
-		 * XXX - what if we already have a filter in the kernel?
-		 */
-		if (install_bpf_program(p, fp) < 0)
-			return (-1);
-		p->md.use_bpf = 0;	/* filtering in userland */
-		return (0);
-	}
+	struct pcap_bpf *pb = p->priv;
 
 	/*
 	 * Free any user-mode filter we might happen to have installed.
@@ -1078,20 +2616,51 @@
 	/*
 	 * Try to install the kernel filter.
 	 */
-	if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {
+	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) {
 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
 		    pcap_strerror(errno));
 		return (-1);
 	}
-	p->md.use_bpf = 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).
+	 * install_bpf_program() validates the program.
+	 *
+	 * XXX - what if we already have a filter in the kernel?
 	 */
-	p->cc = 0;
+	if (install_bpf_program(p, fp) < 0)
+		return (-1);
+	pb->filtering_in_kernel = 0;	/* filtering in userland */
 	return (0);
 }