File: [local] / src / lib / libpcap / pcap.c (download)
Revision 1.11, Sun Sep 2 15:19:18 2007 UTC (16 years, 9 months ago) by deraadt
Branch: MAIN
CVS Tags: OPENBSD_4_7_BASE, OPENBSD_4_7, OPENBSD_4_6_BASE, OPENBSD_4_6, OPENBSD_4_5_BASE, OPENBSD_4_5, OPENBSD_4_4_BASE, OPENBSD_4_4, OPENBSD_4_3_BASE, OPENBSD_4_3 Changes since 1.10: +2 -2 lines
use calloc() to avoid malloc(n * m) overflows; checked by djm canacar jsg
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/* $OpenBSD: pcap.c,v 1.11 2007/09/02 15:19:18 deraadt Exp $ */
/*
* 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.
*/
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#include "pcap-int.h"
static const char pcap_version_string[] = "OpenBSD libpcap";
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);
}
struct pkt_for_fakecallback {
struct pcap_pkthdr *hdr;
const u_char **pkt;
};
static void
pcap_fakecallback(u_char *userData, const struct pcap_pkthdr *h,
const u_char *pkt)
{
struct pkt_for_fakecallback *sp = (struct pkt_for_fakecallback *)userData;
*sp->hdr = *h;
*sp->pkt = pkt;
}
int
pcap_next_ex(pcap_t *p, struct pcap_pkthdr **pkt_header,
const u_char **pkt_data)
{
struct pkt_for_fakecallback s;
s.hdr = &p->pcap_header;
s.pkt = pkt_data;
/* Saves a pointer to the packet headers */
*pkt_header= &p->pcap_header;
if (p->sf.rfile != NULL) {
int status;
/* We are on an offline capture */
status = pcap_offline_read(p, 1, pcap_fakecallback,
(u_char *)&s);
/*
* Return codes for pcap_offline_read() are:
* - 0: EOF
* - -1: error
* - >1: OK
* The first one ('0') conflicts with the return code of
* 0 from pcap_read() meaning "no packets arrived before
* the timeout expired", so we map it to -2 so you can
* distinguish between an EOF from a savefile and a
* "no packets arrived before the timeout expired, try
* again" from a live capture.
*/
if (status == 0)
return (-2);
else
return (status);
}
/*
* Return codes for pcap_read() are:
* - 0: timeout
* - -1: error
* - -2: loop was broken out of with pcap_breakloop()
* - >1: OK
* The first one ('0') conflicts with the return code of 0 from
* pcap_offline_read() meaning "end of file".
*/
return (pcap_read(p, 1, pcap_fakecallback, (u_char *)&s));
}
/*
* Force the loop in "pcap_read()" or "pcap_read_offline()" to terminate.
*/
void
pcap_breakloop(pcap_t *p)
{
p->break_loop = 1;
}
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*)calloc(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);
}
}
struct dlt_choice {
const char *name;
const char *description;
int dlt;
};
static struct dlt_choice dlts[] = {
#define DLT_CHOICE(code, description) { #code, description, code }
DLT_CHOICE(DLT_NULL, "no link-layer encapsulation"),
DLT_CHOICE(DLT_EN10MB, "Ethernet (10Mb)"),
DLT_CHOICE(DLT_EN3MB, "Experimental Ethernet (3Mb)"),
DLT_CHOICE(DLT_AX25, "Amateur Radio AX.25"),
DLT_CHOICE(DLT_PRONET, "Proteon ProNET Token Ring"),
DLT_CHOICE(DLT_CHAOS, "Chaos"),
DLT_CHOICE(DLT_IEEE802, "IEEE 802 Networks"),
DLT_CHOICE(DLT_ARCNET, "ARCNET"),
DLT_CHOICE(DLT_SLIP, "Serial Line IP"),
DLT_CHOICE(DLT_PPP, "Point-to-point Protocol"),
DLT_CHOICE(DLT_FDDI, "FDDI"),
DLT_CHOICE(DLT_ATM_RFC1483, "LLC/SNAP encapsulated atm"),
DLT_CHOICE(DLT_LOOP, "loopback type (af header)"),
DLT_CHOICE(DLT_ENC, "IPSEC enc type (af header, spi, flags)"),
DLT_CHOICE(DLT_RAW, "raw IP"),
DLT_CHOICE(DLT_SLIP_BSDOS, "BSD/OS Serial Line IP"),
DLT_CHOICE(DLT_PPP_BSDOS, "BSD/OS Point-to-point Protocol"),
DLT_CHOICE(DLT_OLD_PFLOG, "Packet filter logging, old (XXX remove?)"),
DLT_CHOICE(DLT_PFSYNC, "Packet filter state syncing"),
DLT_CHOICE(DLT_PPP_ETHER, "PPP over Ethernet; session only w/o ether header"),
DLT_CHOICE(DLT_IEEE802_11, "IEEE 802.11 wireless"),
DLT_CHOICE(DLT_PFLOG, "Packet filter logging, by pcap people"),
DLT_CHOICE(DLT_IEEE802_11_RADIO, "IEEE 802.11 plus WLAN header"),
#undef DLT_CHOICE
{ NULL, NULL, -1}
};
int
pcap_datalink_name_to_val(const char *name)
{
int i;
for (i = 0; dlts[i].name != NULL; i++) {
/* Skip leading "DLT_" */
if (strcasecmp(dlts[i].name + 4, name) == 0)
return (dlts[i].dlt);
}
return (-1);
}
const char *
pcap_datalink_val_to_name(int dlt)
{
int i;
for (i = 0; dlts[i].name != NULL; i++) {
if (dlts[i].dlt == dlt)
return (dlts[i].name + 4); /* Skip leading "DLT_" */
}
return (NULL);
}
const char *
pcap_datalink_val_to_description(int dlt)
{
int i;
for (i = 0; dlts[i].name != NULL; i++) {
if (dlts[i].dlt == dlt)
return (dlts[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)
{
return (p->fd);
}
void
pcap_perror(pcap_t *p, char *prefix)
{
fprintf(stderr, "%s: %s\n", prefix, p->errbuf);
}
int
pcap_get_selectable_fd(pcap_t *p)
{
return (p->fd);
}
char *
pcap_geterr(pcap_t *p)
{
return (p->errbuf);
}
int
pcap_getnonblock(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);
}
int
pcap_setnonblock(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);
}
/*
* 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));
p->snapshot = snaplen;
p->linktype = linktype;
p->fd = -1;
return p;
}
void
pcap_close(pcap_t *p)
{
/*XXX*/
if (p->fd >= 0)
close(p->fd);
if (p->sf.rfile != NULL) {
(void)fclose(p->sf.rfile);
if (p->sf.base != NULL)
free(p->sf.base);
} else if (p->buffer != NULL)
free(p->buffer);
#ifdef linux
if (p->md.device != NULL)
free(p->md.device);
#endif
pcap_freecode(&p->fcode);
if (p->dlt_list != NULL)
free(p->dlt_list);
free(p);
}
const char *
pcap_lib_version(void)
{
return (pcap_version_string);
}