/*
 * Copyright (c) 1993, 1994, 1995, 1996, 1997, 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 the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the Computer Systems
 *	Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.42 2002-12-19 09:05:48 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef WIN32
#include <pcap-stdinc.h>
#else /* WIN32 */
#include <sys/types.h>
#endif /* WIN32 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef WIN32
#include <unistd.h>
#endif
#include <fcntl.h>
#include <errno.h>

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

#include "pcap-int.h"

int
pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{

	if (p->sf.rfile != NULL)
		return (pcap_offline_read(p, cnt, callback, user));
	return (pcap_read(p, cnt, callback, user));
}

int
pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
	register int n;

	for (;;) {
		if (p->sf.rfile != NULL)
			n = pcap_offline_read(p, cnt, callback, user);
		else {
			/*
			 * XXX keep reading until we get something
			 * (or an error occurs)
			 */
			do {
				n = pcap_read(p, cnt, callback, user);
			} while (n == 0);
		}
		if (n <= 0)
			return (n);
		if (cnt > 0) {
			cnt -= n;
			if (cnt <= 0)
				return (0);
		}
	}
}

struct singleton {
	struct pcap_pkthdr *hdr;
	const u_char *pkt;
};


static void
pcap_oneshot(u_char *userData, const struct pcap_pkthdr *h, const u_char *pkt)
{
	struct singleton *sp = (struct singleton *)userData;
	*sp->hdr = *h;
	sp->pkt = pkt;
}

const u_char *
pcap_next(pcap_t *p, struct pcap_pkthdr *h)
{
	struct singleton s;

	s.hdr = h;
	if (pcap_dispatch(p, 1, pcap_oneshot, (u_char*)&s) <= 0)
		return (0);
	return (s.pkt);
}

int
pcap_datalink(pcap_t *p)
{
	return (p->linktype);
}

int
pcap_list_datalinks(pcap_t *p, int **dlt_buffer)
{
	if (p->dlt_count == 0) {
		/*
		 * We couldn't fetch the list of DLTs, which means
		 * this platform doesn't support changing the
		 * DLT for an interface.  Return a list of DLTs
		 * containing only the DLT this device supports.
		 */
		*dlt_buffer = (int*)malloc(sizeof(**dlt_buffer));
		if (*dlt_buffer == NULL) {
			(void)snprintf(p->errbuf, sizeof(p->errbuf),
			    "malloc: %s", pcap_strerror(errno));
			return (-1);
		}
		**dlt_buffer = p->linktype;
		return (1);
	} else {
		*dlt_buffer = (int*)malloc(sizeof(**dlt_buffer) * p->dlt_count);
		if (*dlt_buffer == NULL) {
			(void)snprintf(p->errbuf, sizeof(p->errbuf),
			    "malloc: %s", pcap_strerror(errno));
			return (-1);
		}
		(void)memcpy(*dlt_buffer, p->dlt_list,
		    sizeof(**dlt_buffer) * p->dlt_count);
		return (p->dlt_count);
	}
}

int
pcap_set_datalink(pcap_t *p, int dlt)
{
	int i;
	const char *dlt_name;

	if (p->dlt_count == 0) {
		/*
		 * We couldn't fetch the list of DLTs, which means
		 * this platform doesn't support changing the
		 * DLT for an interface.  Check whether the new
		 * DLT is the one this interface supports.
		 */
		if (p->linktype != dlt)
			goto unsupported;

		/*
		 * It is, so there's nothing we need to do here.
		 */
		return (0);
	}
	for (i = 0; i < p->dlt_count; i++)
		if (p->dlt_list[i] == dlt)
			break;
	if (i >= p->dlt_count)
		goto unsupported;
	if (pcap_set_datalink_platform(p, dlt) == -1)
		return (-1);
	p->linktype = dlt;
	return (0);

unsupported:
	dlt_name = pcap_datalink_val_to_name(dlt);
	if (dlt_name != NULL) {
		(void) snprintf(p->errbuf, sizeof(p->errbuf),
		    "%s is not one of the DLTs supported by this device",
		    dlt_name);
	} else {
		(void) snprintf(p->errbuf, sizeof(p->errbuf),
		    "DLT %d is not one of the DLTs supported by this device",
		    dlt);
	}
	return (-1);
}

struct dlt_choice {
	const char *name;
	int	dlt;
};

#define DLT_CHOICE(code) { #code, code }
#define DLT_CHOICE_SENTINEL { NULL, 0 }

static struct dlt_choice dlt_choices[] = {
	DLT_CHOICE(DLT_ARCNET),
	DLT_CHOICE(DLT_EN10MB),
	DLT_CHOICE(DLT_SLIP),
	DLT_CHOICE(DLT_SLIP_BSDOS),
	DLT_CHOICE(DLT_NULL),
	DLT_CHOICE(DLT_LOOP),
	DLT_CHOICE(DLT_PPP),
	DLT_CHOICE(DLT_C_HDLC),
	DLT_CHOICE(DLT_PPP_SERIAL),
	DLT_CHOICE(DLT_PPP_ETHER),
	DLT_CHOICE(DLT_PPP_BSDOS),
	DLT_CHOICE(DLT_FDDI),
	DLT_CHOICE(DLT_IEEE802),
	DLT_CHOICE(DLT_IEEE802_11),
	DLT_CHOICE(DLT_PRISM_HEADER),
	DLT_CHOICE(DLT_IEEE802_11_RADIO),
	DLT_CHOICE(DLT_ATM_RFC1483),
	DLT_CHOICE(DLT_ATM_CLIP),
	DLT_CHOICE(DLT_SUNATM),
	DLT_CHOICE(DLT_RAW),
	DLT_CHOICE(DLT_LINUX_SLL),
	DLT_CHOICE(DLT_LTALK),
	DLT_CHOICE(DLT_IP_OVER_FC),
	DLT_CHOICE(DLT_FRELAY),
	DLT_CHOICE_SENTINEL
};

/*
 * This array is designed for mapping upper and lower case letter
 * together for a case independent comparison.  The mappings are
 * based upon ascii character sequences.
 */
static const u_char charmap[] = {
	'\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
	'\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
	'\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
	'\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
	'\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
	'\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
	'\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
	'\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
	'\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
	'\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
	'\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
	'\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
	'\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
	'\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
	'\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
	'\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177',
	'\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207',
	'\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217',
	'\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227',
	'\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237',
	'\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247',
	'\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257',
	'\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267',
	'\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277',
	'\300', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
	'\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
	'\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
	'\370', '\371', '\372', '\333', '\334', '\335', '\336', '\337',
	'\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
	'\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
	'\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
	'\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377',
};

static int
pcap_strcasecmp(const char *s1, const char *s2)
{
	register const u_char	*cm = charmap,
				*us1 = (u_char *)s1,
				*us2 = (u_char *)s2;

	while (cm[*us1] == cm[*us2++])
		if (*us1++ == '\0')
			return(0);
	return (cm[*us1] - cm[*--us2]);
}

int
pcap_datalink_name_to_val(const char *name)
{
	int i;

	for (i = 0; dlt_choices[i].name != NULL; i++) {
		if (pcap_strcasecmp(dlt_choices[i].name + sizeof("DLT_") - 1,
		    name) == 0)
			return (dlt_choices[i].dlt);
	}
	return (-1);
}

const char *
pcap_datalink_val_to_name(int dlt)
{
	int i;

	for (i = 0; dlt_choices[i].name != NULL; i++) {
		if (dlt_choices[i].dlt == dlt)
			return (dlt_choices[i].name + sizeof("DLT_") - 1);
	}
	return (NULL);
}

int
pcap_snapshot(pcap_t *p)
{
	return (p->snapshot);
}

int
pcap_is_swapped(pcap_t *p)
{
	return (p->sf.swapped);
}

int
pcap_major_version(pcap_t *p)
{
	return (p->sf.version_major);
}

int
pcap_minor_version(pcap_t *p)
{
	return (p->sf.version_minor);
}

FILE *
pcap_file(pcap_t *p)
{
	return (p->sf.rfile);
}

int
pcap_fileno(pcap_t *p)
{
#ifndef WIN32
	return (p->fd);
#else
	if (p->adapter != NULL)
		return ((int)(DWORD)p->adapter->hFile);
	else
		return (-1);
#endif
}

void
pcap_perror(pcap_t *p, char *prefix)
{
	fprintf(stderr, "%s: %s\n", prefix, p->errbuf);
}

char *
pcap_geterr(pcap_t *p)
{
	return (p->errbuf);
}

/*
 * NOTE: in the future, these may need to call platform-dependent routines,
 * e.g. on platforms with memory-mapped packet-capture mechanisms where
 * "pcap_read()" uses "select()" or "poll()" to wait for packets to arrive.
 */
int
pcap_getnonblock(pcap_t *p, char *errbuf)
{
#ifndef WIN32
	int fdflags;
#endif

	if (p->sf.rfile != NULL) {
		/*
		 * This is a savefile, not a live capture file, so
		 * never say it's in non-blocking mode.
		 */
		return (0);
	}
#ifndef WIN32
	fdflags = fcntl(p->fd, F_GETFL, 0);
	if (fdflags == -1) {
		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_GETFL: %s",
		    pcap_strerror(errno));
		return (-1);
	}
	if (fdflags & O_NONBLOCK)
		return (1);
	else
		return (0);
#else
	return (p->nonblock);
#endif
}

int
pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf)
{
#ifndef WIN32
	int fdflags;
#else
	int newtimeout;
#endif
	if (p->dlt_list != NULL)
		free(p->dlt_list);

	if (p->sf.rfile != NULL) {
		/*
		 * This is a savefile, not a live capture file, so
		 * ignore requests to put it in non-blocking mode.
		 */
		return (0);
	}
#ifndef WIN32
	fdflags = fcntl(p->fd, F_GETFL, 0);
	if (fdflags == -1) {
		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_GETFL: %s",
		    pcap_strerror(errno));
		return (-1);
	}
	if (nonblock)
		fdflags |= O_NONBLOCK;
	else
		fdflags &= ~O_NONBLOCK;
	if (fcntl(p->fd, F_SETFL, fdflags) == -1) {
		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_SETFL: %s",
		    pcap_strerror(errno));
		return (-1);
	}
#else
	if (nonblock) {
		/*
		 * Set the read timeout to -1 for non-blocking mode.
		 */
		newtimeout = -1;
	} else {
		/*
		 * Restore the timeout set when the device was opened.
		 * (Note that this may be -1, in which case we're not
		 * really leaving non-blocking mode.)
		 */
		newtimeout = p->timeout;
	}
	if (!PacketSetReadTimeout(p->adapter, newtimeout)) {
		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
		    "PacketSetReadTimeout: %s", pcap_win32strerror());
		return (-1);
	}
	p->nonblock = (newtimeout == -1);
#endif
	return (0);
}

#ifdef WIN32
/*
 * Generate a string for the last Win32-specific error (i.e. an error generated when 
 * calling a Win32 API).
 * For errors occurred during standard C calls, we still use pcap_strerror()
 */
char *
pcap_win32strerror(void)
{
	DWORD error;
	static char errbuf[PCAP_ERRBUF_SIZE+1];
	int errlen;

	error = GetLastError();
	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, error, 0, errbuf,
	    PCAP_ERRBUF_SIZE, NULL);

	/*
	 * "FormatMessage()" "helpfully" sticks CR/LF at the end of the
	 * message.  Get rid of it.
	 */
	errlen = strlen(errbuf);
	if (errlen >= 2) {
		errbuf[errlen - 1] = '\0';
		errbuf[errlen - 2] = '\0';
	}
	return (errbuf);
}
#endif

/*
 * Not all systems have strerror().
 */
char *
pcap_strerror(int errnum)
{
#ifdef HAVE_STRERROR
	return (strerror(errnum));
#else
	extern int sys_nerr;
	extern const char *const sys_errlist[];
	static char ebuf[20];

	if ((unsigned int)errnum < sys_nerr)
		return ((char *)sys_errlist[errnum]);
	(void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum);
	return(ebuf);
#endif
}

pcap_t *
pcap_open_dead(int linktype, int snaplen)
{
	pcap_t *p;

	p = malloc(sizeof(*p));
	if (p == NULL)
		return NULL;
	memset (p, 0, sizeof(*p));
#ifndef WIN32
	p->fd = -1;
#else
	p->adapter = NULL;
#endif /* WIN32 */
	p->snapshot = snaplen;
	p->linktype = linktype;
	return p;
}

void
pcap_close(pcap_t *p)
{
	/*XXX*/
#ifndef WIN32
	if (p->fd >= 0) {
#ifdef linux
		pcap_close_linux(p);
#endif
		close(p->fd);
	}
#else /* WIN32 */
	if (p->adapter != NULL) {
		PacketCloseAdapter(p->adapter);
		p->adapter = NULL;
	}
#endif /* WIN32 */
	if (p->sf.rfile != NULL) {
		if (p->sf.rfile != stdin)
			(void)fclose(p->sf.rfile);
		if (p->sf.base != NULL)
			free(p->sf.base);
	} else if (p->buffer != NULL)
		free(p->buffer);

	pcap_freecode(&p->fcode);
	free(p);
}