pcap.c

用来监视网络通信数据的源代码和应用程序,方便网络程序底层开发.

	(u_char)'\154', (u_char)'\155', (u_char)'\156', (u_char)'\157',
	(u_char)'\160', (u_char)'\161', (u_char)'\162', (u_char)'\163',
	(u_char)'\164', (u_char)'\165', (u_char)'\166', (u_char)'\167',
	(u_char)'\170', (u_char)'\171', (u_char)'\172', (u_char)'\173',
	(u_char)'\174', (u_char)'\175', (u_char)'\176', (u_char)'\177',
	(u_char)'\200', (u_char)'\201', (u_char)'\202', (u_char)'\203',
	(u_char)'\204', (u_char)'\205', (u_char)'\206', (u_char)'\207',
	(u_char)'\210', (u_char)'\211', (u_char)'\212', (u_char)'\213',
	(u_char)'\214', (u_char)'\215', (u_char)'\216', (u_char)'\217',
	(u_char)'\220', (u_char)'\221', (u_char)'\222', (u_char)'\223',
	(u_char)'\224', (u_char)'\225', (u_char)'\226', (u_char)'\227',
	(u_char)'\230', (u_char)'\231', (u_char)'\232', (u_char)'\233',
	(u_char)'\234', (u_char)'\235', (u_char)'\236', (u_char)'\237',
	(u_char)'\240', (u_char)'\241', (u_char)'\242', (u_char)'\243',
	(u_char)'\244', (u_char)'\245', (u_char)'\246', (u_char)'\247',
	(u_char)'\250', (u_char)'\251', (u_char)'\252', (u_char)'\253',
	(u_char)'\254', (u_char)'\255', (u_char)'\256', (u_char)'\257',
	(u_char)'\260', (u_char)'\261', (u_char)'\262', (u_char)'\263',
	(u_char)'\264', (u_char)'\265', (u_char)'\266', (u_char)'\267',
	(u_char)'\270', (u_char)'\271', (u_char)'\272', (u_char)'\273',
	(u_char)'\274', (u_char)'\275', (u_char)'\276', (u_char)'\277',
	(u_char)'\300', (u_char)'\341', (u_char)'\342', (u_char)'\343',
	(u_char)'\344', (u_char)'\345', (u_char)'\346', (u_char)'\347',
	(u_char)'\350', (u_char)'\351', (u_char)'\352', (u_char)'\353',
	(u_char)'\354', (u_char)'\355', (u_char)'\356', (u_char)'\357',
	(u_char)'\360', (u_char)'\361', (u_char)'\362', (u_char)'\363',
	(u_char)'\364', (u_char)'\365', (u_char)'\366', (u_char)'\367',
	(u_char)'\370', (u_char)'\371', (u_char)'\372', (u_char)'\333',
	(u_char)'\334', (u_char)'\335', (u_char)'\336', (u_char)'\337',
	(u_char)'\340', (u_char)'\341', (u_char)'\342', (u_char)'\343',
	(u_char)'\344', (u_char)'\345', (u_char)'\346', (u_char)'\347',
	(u_char)'\350', (u_char)'\351', (u_char)'\352', (u_char)'\353',
	(u_char)'\354', (u_char)'\355', (u_char)'\356', (u_char)'\357',
	(u_char)'\360', (u_char)'\361', (u_char)'\362', (u_char)'\363',
	(u_char)'\364', (u_char)'\365', (u_char)'\366', (u_char)'\367',
	(u_char)'\370', (u_char)'\371', (u_char)'\372', (u_char)'\373',
	(u_char)'\374', (u_char)'\375', (u_char)'\376', (u_char)'\377',
};

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);
}

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

	for (i = 0; dlt_choices[i].name != NULL; i++) {
		if (dlt_choices[i].dlt == dlt)
			return (dlt_choices[i].description);
	}
	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)
{
#ifdef HAVE_REMOTE
	if (p->rmt_clientside)
		return(p->rmt_sockdata);
#endif /* HAVE_REMOTE */

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

#ifndef WIN32
int
pcap_get_selectable_fd(pcap_t *p)
{
	return (p->selectable_fd);
}
#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);
}

int
pcap_getnonblock(pcap_t *p, char *errbuf)
{
	return p->getnonblock_op(p, errbuf);
}

/*
 * Get the current non-blocking mode setting, under the assumption that
 * it's just the standard POSIX non-blocking flag.
 *
 * We don't look at "p->nonblock", in case somebody tweaked the FD
 * directly.
 */
#ifndef WIN32
int
pcap_getnonblock_fd(pcap_t *p, char *errbuf)
{
	int fdflags;

	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);
}
#endif

int
pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf)
{
	return p->setnonblock_op(p, nonblock, errbuf);
}

#ifndef WIN32
/*
 * Set non-blocking mode, under the assumption that it's just the
 * standard POSIX non-blocking flag.  (This can be called by the
 * per-platform non-blocking-mode routine if that routine also
 * needs to do some additional work.)
 */
int
pcap_setnonblock_fd(pcap_t *p, int nonblock, char *errbuf)
{
	int fdflags;

	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);
	}
	return (0);
}
#endif

#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
}

int
pcap_setfilter(pcap_t *p, struct bpf_program *fp)
{
	return p->setfilter_op(p, fp);
}

int
pcap_stats(pcap_t *p, struct pcap_stat *ps)
{
	return p->stats_op(p, ps);
}

static int
pcap_stats_dead(pcap_t *p, struct pcap_stat *ps)
{
	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
	    "Statistics aren't available from a pcap_open_dead pcap_t");
	return (-1);
}

static void
pcap_close_dead(pcap_t *p)
{
	/* Nothing to do. */
}

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));
	p->snapshot = snaplen;
	p->linktype = linktype;
	p->stats_op = pcap_stats_dead;
	p->close_op = pcap_close_dead;
	return p;
}

void
pcap_close(pcap_t *p)
{
	p->close_op(p);
	if (p->dlt_list != NULL)
		free(p->dlt_list);
	pcap_freecode(&p->fcode);
	free(p);
}

/*
 * We make the version string static, and return a pointer to it, rather
 * than exporting the version string directly.  On at least some UNIXes,
 * if you import data from a shared library into an program, the data is
 * bound into the program binary, so if the string in the version of the
 * library with which the program was linked isn't the same as the
 * string in the version of the library with which the program is being
 * run, various undesirable things may happen (warnings, the string
 * being the one from the version of the library with which the program
 * was linked, or even weirder things, such as the string being the one
 * from the library but being truncated).
 */
#ifdef WIN32
/*
 * XXX - it'd be nice if we could somehow generate the WinPcap and libpcap
 * version numbers when building WinPcap.  (It'd be nice to do so for
 * the packet.dll version number as well.)
 */
static const char wpcap_version_string[] = "3.1 beta4";
static const char pcap_version_string_fmt[] =
    "WinPcap version %s, based on libpcap version 0.8.3";
static const char pcap_version_string_packet_dll_fmt[] =
    "WinPcap version %s (packet.dll version %s), based on libpcap version 0.8.3";
static char *pcap_version_string;

const char *
pcap_lib_version(void)
{
	char *packet_version_string;
	size_t pcap_version_string_len;

	if (pcap_version_string == NULL) {
		/*
		 * Generate the version string.
		 */
		packet_version_string = PacketGetVersion();
		if (strcmp(wpcap_version_string, packet_version_string) == 0) {
			/*
			 * WinPcap version string and packet.dll version
			 * string are the same; just report the WinPcap
			 * version.
			 */
			pcap_version_string_len =
			    (sizeof pcap_version_string_fmt - 2) +
			    strlen(wpcap_version_string);
			pcap_version_string = malloc(pcap_version_string_len);
			sprintf(pcap_version_string, pcap_version_string_fmt,
			    wpcap_version_string);
		} else {
			/*
			 * WinPcap version string and packet.dll version
			 * string are different; that shouldn't be the
			 * case (the two libraries should come from the
			 * same version of WinPcap), so we report both
			 * versions.
			 */
			pcap_version_string_len =
			    (sizeof pcap_version_string_packet_dll_fmt - 4) +
			    strlen(wpcap_version_string) +
			    strlen(packet_version_string);
			pcap_version_string = malloc(pcap_version_string_len);
			sprintf(pcap_version_string,
			    pcap_version_string_packet_dll_fmt,
			    wpcap_version_string, packet_version_string);
		}
	}
	return (pcap_version_string);
}
#else
#include "version.h"

const char *
pcap_lib_version(void)
{
	return (pcap_version_string);
}
#endif