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/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
/*
* Copyright (c) 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[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.8.2.2 2005/06/29 06:43:31 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/time.h> /* concession to AIX */
struct mbuf; /* Squelch compiler warnings on some platforms for */
struct rtentry; /* declarations in <net/if.h> */
#include <net/if.h>
#include <netinet/in.h>
#include <ctype.h>
#include <errno.h>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "pcap-int.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
/*
* This is fun.
*
* In older BSD systems, socket addresses were fixed-length, and
* "sizeof (struct sockaddr)" gave the size of the structure.
* All addresses fit within a "struct sockaddr".
*
* In newer BSD systems, the socket address is variable-length, and
* there's an "sa_len" field giving the length of the structure;
* this allows socket addresses to be longer than 2 bytes of family
* and 14 bytes of data.
*
* Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
* variant of the old BSD scheme (with "struct sockaddr_storage" rather
* than "struct sockaddr"), and some use the new BSD scheme.
*
* Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
* macro that determines the size based on the address family. Other
* versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
* but not in the final version).
*
* We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
* SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
* address in an entry returned by SIOCGIFCONF.
*/
#ifndef SA_LEN
#ifdef HAVE_SOCKADDR_SA_LEN
#define SA_LEN(addr) ((addr)->sa_len)
#else /* HAVE_SOCKADDR_SA_LEN */
#define SA_LEN(addr) (sizeof (struct sockaddr))
#endif /* HAVE_SOCKADDR_SA_LEN */
#endif /* SA_LEN */
/*
* This is also fun.
*
* There is no ioctl that returns the amount of space required for all
* the data that SIOCGIFCONF could return, and if a buffer is supplied
* that's not large enough for all the data SIOCGIFCONF could return,
* on at least some platforms it just returns the data that'd fit with
* no indication that there wasn't enough room for all the data, much
* less an indication of how much more room is required.
*
* The only way to ensure that we got all the data is to pass a buffer
* large enough that the amount of space in the buffer *not* filled in
* is greater than the largest possible entry.
*
* We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
* that no address is more than 255 bytes (on systems where the "sa_len"
* field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
* case, and addresses are unlikely to be bigger than that in any case).
*/
#define MAX_SA_LEN 255
#ifdef HAVE_PROC_NET_DEV
/*
* Get from "/proc/net/dev" all interfaces listed there; if they're
* already in the list of interfaces we have, that won't add another
* instance, but if they're not, that'll add them.
*
* We don't bother getting any addresses for them; it appears you can't
* use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
* although some other types of addresses can be fetched with SIOCGIFADDR,
* we don't bother with them for now.
*
* We also don't fail if we couldn't open "/proc/net/dev"; we just leave
* the list of interfaces as is.
*/
static int
scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
{
FILE *proc_net_f;
char linebuf[512];
int linenum;
unsigned char *p;
char name[512]; /* XXX - pick a size */
char *q, *saveq;
struct ifreq ifrflags;
int ret = 0;
proc_net_f = fopen("/proc/net/dev", "r");
if (proc_net_f == NULL)
return (0);
for (linenum = 1;
fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
/*
* Skip the first two lines - they're headers.
*/
if (linenum <= 2)
continue;
p = &linebuf[0];
/*
* Skip leading white space.
*/
while (*p != '\0' && isspace(*p))
p++;
if (*p == '\0' || *p == '\n')
continue; /* blank line */
/*
* Get the interface name.
*/
q = &name[0];
while (*p != '\0' && !isspace(*p)) {
if (*p == ':') {
/*
* This could be the separator between a
* name and an alias number, or it could be
* the separator between a name with no
* alias number and the next field.
*
* If there's a colon after digits, it
* separates the name and the alias number,
* otherwise it separates the name and the
* next field.
*/
saveq = q;
while (isdigit(*p))
*q++ = *p++;
if (*p != ':') {
/*
* That was the next field,
* not the alias number.
*/
q = saveq;
}
break;
} else
*q++ = *p++;
}
*q = '\0';
/*
* Get the flags for this interface, and skip it if
* it's not up.
*/
strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
if (errno == ENXIO)
continue;
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFFLAGS: %.*s: %s",
(int)sizeof(ifrflags.ifr_name),
ifrflags.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
if (!(ifrflags.ifr_flags & IFF_UP))
continue;
/*
* Add an entry for this interface, with no addresses.
*/
if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
errbuf) == -1) {
/*
* Failure.
*/
ret = -1;
break;
}
}
if (ret != -1) {
/*
* Well, we didn't fail for any other reason; did we
* fail due to an error reading the file?
*/
if (ferror(proc_net_f)) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"Error reading /proc/net/dev: %s",
pcap_strerror(errno));
ret = -1;
}
}
(void)fclose(proc_net_f);
return (ret);
}
#endif /* HAVE_PROC_NET_DEV */
/*
* Get a list of all interfaces that are up and that we can open.
* Returns -1 on error, 0 otherwise.
* The list, as returned through "alldevsp", may be null if no interfaces
* were up and could be opened.
*
* This is the implementation used on platforms that have SIOCGIFCONF but
* don't have any other mechanism for getting a list of interfaces.
*
* XXX - or platforms that have other, better mechanisms but for which
* we don't yet have code to use that mechanism; I think there's a better
* way on Linux, for example.
*/
int
pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
{
pcap_if_t *devlist = NULL;
register int fd;
register struct ifreq *ifrp, *ifend, *ifnext;
int n;
struct ifconf ifc;
char *buf = NULL;
unsigned buf_size;
#if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
char *p, *q;
#endif
struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
struct sockaddr *netmask, *broadaddr, *dstaddr;
size_t netmask_size, broadaddr_size, dstaddr_size;
int ret = 0;
/*
* Create a socket from which to fetch the list of interfaces.
*/
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"socket: %s", pcap_strerror(errno));
return (-1);
}
/*
* Start with an 8K buffer, and keep growing the buffer until
* we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
* bytes left over in the buffer or we fail to get the
* interface list for some reason other than EINVAL (which is
* presumed here to mean "buffer is too small").
*/
buf_size = 8192;
for (;;) {
buf = malloc(buf_size);
if (buf == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
(void)close(fd);
return (-1);
}
ifc.ifc_len = buf_size;
ifc.ifc_buf = buf;
memset(buf, 0, buf_size);
if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
&& errno != EINVAL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFCONF: %s", pcap_strerror(errno));
(void)close(fd);
free(buf);
return (-1);
}
if (ifc.ifc_len < buf_size &&
(buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
break;
free(buf);
buf_size *= 2;
}
ifrp = (struct ifreq *)buf;
ifend = (struct ifreq *)(buf + ifc.ifc_len);
for (; ifrp < ifend; ifrp = ifnext) {
/*
* XXX - what if this isn't an IPv4 address? Can
* we still get the netmask, etc. with ioctls on
* an IPv4 socket?
*
* The answer is probably platform-dependent, and
* if the answer is "no" on more than one platform,
* the way you work around it is probably platform-
* dependent as well.
*/
n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
if (n < sizeof(*ifrp))
ifnext = ifrp + 1;
else
ifnext = (struct ifreq *)((char *)ifrp + n);
/*
* XXX - The 32-bit compatibility layer for Linux on IA-64
* is slightly broken. It correctly converts the structures
* to and from kernel land from 64 bit to 32 bit but
* doesn't update ifc.ifc_len, leaving it larger than the
* amount really used. This means we read off the end
* of the buffer and encounter an interface with an
* "empty" name. Since this is highly unlikely to ever
* occur in a valid case we can just finish looking for
* interfaces if we see an empty name.
*/
if (!(*ifrp->ifr_name))
break;
/*
* Skip entries that begin with "dummy".
* XXX - what are these? Is this Linux-specific?
* Are there platforms on which we shouldn't do this?
*/
if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
continue;
/*
* Get the flags for this interface, and skip it if it's
* not up.
*/
strncpy(ifrflags.ifr_name, ifrp->ifr_name,
sizeof(ifrflags.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
if (errno == ENXIO)
continue;
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFFLAGS: %.*s: %s",
(int)sizeof(ifrflags.ifr_name),
ifrflags.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
if (!(ifrflags.ifr_flags & IFF_UP))
continue;
/*
* Get the netmask for this address on this interface.
*/
strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
sizeof(ifrnetmask.ifr_name));
memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
sizeof(ifrnetmask.ifr_addr));
if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
if (errno == EADDRNOTAVAIL) {
/*
* Not available.
*/
netmask = NULL;
netmask_size = 0;
} else {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFNETMASK: %.*s: %s",
(int)sizeof(ifrnetmask.ifr_name),
ifrnetmask.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
} else {
netmask = &ifrnetmask.ifr_addr;
netmask_size = SA_LEN(netmask);
}
/*
* Get the broadcast address for this address on this
* interface (if any).
*/
if (ifrflags.ifr_flags & IFF_BROADCAST) {
strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
sizeof(ifrbroadaddr.ifr_name));
memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
sizeof(ifrbroadaddr.ifr_addr));
if (ioctl(fd, SIOCGIFBRDADDR,
(char *)&ifrbroadaddr) < 0) {
if (errno == EADDRNOTAVAIL) {
/*
* Not available.
*/
broadaddr = NULL;
broadaddr_size = 0;
} else {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFBRDADDR: %.*s: %s",
(int)sizeof(ifrbroadaddr.ifr_name),
ifrbroadaddr.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
} else {
broadaddr = &ifrbroadaddr.ifr_broadaddr;
broadaddr_size = SA_LEN(broadaddr);
}
} else {
/*
* Not a broadcast interface, so no broadcast
* address.
*/
broadaddr = NULL;
broadaddr_size = 0;
}
/*
* Get the destination address for this address on this
* interface (if any).
*/
if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
sizeof(ifrdstaddr.ifr_name));
memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
sizeof(ifrdstaddr.ifr_addr));
if (ioctl(fd, SIOCGIFDSTADDR,
(char *)&ifrdstaddr) < 0) {
if (errno == EADDRNOTAVAIL) {
/*
* Not available.
*/
dstaddr = NULL;
dstaddr_size = 0;
} else {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFDSTADDR: %.*s: %s",
(int)sizeof(ifrdstaddr.ifr_name),
ifrdstaddr.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
} else {
dstaddr = &ifrdstaddr.ifr_dstaddr;
dstaddr_size = SA_LEN(dstaddr);
}
} else {
/*
* Not a point-to-point interface, so no destination
* address.
*/
dstaddr = NULL;
dstaddr_size = 0;
}
#if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
/*
* If this entry has a colon followed by a number at
* the end, it's a logical interface. Those are just
* the way you assign multiple IP addresses to a real
* interface, so an entry for a logical interface should
* be treated like the entry for the real interface;
* we do that by stripping off the ":" and the number.
*/
p = strchr(ifrp->ifr_name, ':');
if (p != NULL) {
/*
* We have a ":"; is it followed by a number?
*/
q = p + 1;
while (isdigit((unsigned char)*q))
q++;
if (*q == '\0') {
/*
* All digits after the ":" until the end.
* Strip off the ":" and everything after
* it.
*/
*p = '\0';
}
}
#endif
/*
* Add information for this address to the list.
*/
if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
ifrflags.ifr_flags, &ifrp->ifr_addr,
SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
broadaddr, broadaddr_size, dstaddr, dstaddr_size,
errbuf) < 0) {
ret = -1;
break;
}
}
free(buf);
#ifdef HAVE_PROC_NET_DEV
if (ret != -1) {
/*
* We haven't had any errors yet; now read "/proc/net/dev",
* and add to the list of interfaces all interfaces listed
* there that we don't already have, because, on Linux,
* SIOCGIFCONF reports only interfaces with IPv4 addresses,
* so you need to read "/proc/net/dev" to get the names of
* the rest of the interfaces.
*/
ret = scan_proc_net_dev(&devlist, fd, errbuf);
}
#endif
(void)close(fd);
if (ret != -1) {
/*
* We haven't had any errors yet; do any platform-specific
* operations to add devices.
*/
if (pcap_platform_finddevs(&devlist, errbuf) < 0)
ret = -1;
}
if (ret == -1) {
/*
* We had an error; free the list we've been constructing.
*/
if (devlist != NULL) {
pcap_freealldevs(devlist);
devlist = NULL;
}
}
*alldevsp = devlist;
return (ret);
}
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