OpenBSD-4.6/lib/libpcap/fad-getad.c
/* -*- 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.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ifaddrs.h>
#include <limits.h>
#include "pcap-int.h"
static struct sockaddr *
dup_sockaddr(struct sockaddr *sa, size_t sa_length)
{
struct sockaddr *newsa;
if ((newsa = malloc(sa_length)) == NULL)
return (NULL);
return (memcpy(newsa, sa, sa_length));
}
static int
get_instance(const char *name)
{
const char *cp, *endcp;
int n;
if (strcmp(name, "any") == 0) {
/*
* Give the "any" device an artificially high instance
* number, so it shows up after all other non-loopback
* interfaces.
*/
return INT_MAX;
}
endcp = name + strlen(name);
for (cp = name; cp < endcp && !isdigit((unsigned char)*cp); ++cp)
continue;
if (isdigit((unsigned char)*cp))
n = atoi(cp);
else
n = 0;
return (n);
}
static int
add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, const char *name,
u_int flags, const char *description, char *errbuf)
{
pcap_t *p;
pcap_if_t *curdev, *prevdev, *nextdev;
int this_instance;
size_t len;
/*
* Can we open this interface for live capture?
*
* We do this check so that interfaces that are supplied
* by the interface enumeration mechanism we're using
* but that don't support packet capture aren't included
* in the list. An example of this is loopback interfaces
* on Solaris; we don't just omit loopback interfaces
* becaue you *can* capture on loopback interfaces on some
* OSes.
*/
p = pcap_open_live(name, 68, 0, 0, errbuf);
if (p == NULL) {
/*
* No. Don't bother including it.
* Don't treat this as an error, though.
*/
*curdev_ret = NULL;
return (0);
}
pcap_close(p);
/*
* Is there already an entry in the list for this interface?
*/
for (curdev = *alldevs; curdev != NULL; curdev = curdev->next) {
if (strcmp(name, curdev->name) == 0)
break; /* yes, we found it */
}
if (curdev == NULL) {
/*
* No, we didn't find it.
* Allocate a new entry.
*/
curdev = calloc(1, sizeof(pcap_if_t));
if (curdev == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"calloc: %s", pcap_strerror(errno));
goto fail;
}
/*
* Fill in the entry.
*/
curdev->next = NULL;
len = strlen(name) + 1;
curdev->name = malloc(len);
if (curdev->name == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
goto fail;
}
strlcpy(curdev->name, name, len);
if (description != NULL) {
/*
* We have a description for this interface.
*/
len = strlen(description) + 1;
curdev->description = malloc(len);
if (curdev->description == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
goto fail;
}
strlcpy(curdev->description, description, len);
}
curdev->addresses = NULL; /* list starts out as empty */
curdev->flags = 0;
if (ISLOOPBACK(name, flags))
curdev->flags |= PCAP_IF_LOOPBACK;
/*
* Add it to the list, in the appropriate location.
* First, get the instance number of this interface.
*/
this_instance = get_instance(name);
/*
* Now look for the last interface with an instance number
* less than or equal to the new interface's instance
* number - except that non-loopback interfaces are
* arbitrarily treated as having interface numbers less
* than those of loopback interfaces, so the loopback
* interfaces are put at the end of the list.
*
* We start with "prevdev" being NULL, meaning we're before
* the first element in the list.
*/
prevdev = NULL;
for (;;) {
/*
* Get the interface after this one.
*/
if (prevdev == NULL) {
/*
* The next element is the first element.
*/
nextdev = *alldevs;
} else
nextdev = prevdev->next;
/*
* Are we at the end of the list?
*/
if (nextdev == NULL) {
/*
* Yes - we have to put the new entry
* after "prevdev".
*/
break;
}
/*
* Is the new interface a non-loopback interface
* and the next interface a loopback interface?
*/
if (!(curdev->flags & PCAP_IF_LOOPBACK) &&
(nextdev->flags & PCAP_IF_LOOPBACK)) {
/*
* Yes, we should put the new entry
* before "nextdev", i.e. after "prevdev".
*/
break;
}
/*
* Is the new interface's instance number less
* than the next interface's instance number,
* and is it the case that the new interface is a
* non-loopback interface or the next interface is
* a loopback interface?
*
* (The goal of both loopback tests is to make
* sure that we never put a loopback interface
* before any non-loopback interface and that we
* always put a non-loopback interface before all
* loopback interfaces.)
*/
if (this_instance < get_instance(nextdev->name) &&
(!(curdev->flags & PCAP_IF_LOOPBACK) ||
(nextdev->flags & PCAP_IF_LOOPBACK))) {
/*
* Yes - we should put the new entry
* before "nextdev", i.e. after "prevdev".
*/
break;
}
prevdev = nextdev;
}
/*
* Insert before "nextdev".
*/
curdev->next = nextdev;
/*
* Insert after "prevdev" - unless "prevdev" is null,
* in which case this is the first interface.
*/
if (prevdev == NULL) {
/*
* This is the first interface. Pass back a
* pointer to it, and put "curdev" before
* "nextdev".
*/
*alldevs = curdev;
} else
prevdev->next = curdev;
}
*curdev_ret = curdev;
return (0);
fail:
if (curdev != NULL) {
free(curdev->name);
free(curdev->description);
free(curdev);
}
return (-1);
}
static int
add_addr_to_iflist(pcap_if_t **alldevs, const char *name, u_int flags,
struct sockaddr *addr, size_t addr_size,
struct sockaddr *netmask, size_t netmask_size,
struct sockaddr *broadaddr, size_t broadaddr_size,
struct sockaddr *dstaddr, size_t dstaddr_size,
char *errbuf)
{
pcap_if_t *curdev;
pcap_addr_t *curaddr, *prevaddr, *nextaddr;
if (add_or_find_if(&curdev, alldevs, name, flags, NULL, errbuf) == -1) {
/*
* Error - give up.
*/
return (-1);
}
if (curdev == NULL) {
/*
* Device wasn't added because it can't be opened.
* Not a fatal error.
*/
return (0);
}
/*
* "curdev" is an entry for this interface; add an entry for this
* address to its list of addresses.
*
* Allocate the new entry and fill it in.
*/
curaddr = calloc(1, sizeof(pcap_addr_t));
if (curaddr == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"calloc: %s", pcap_strerror(errno));
goto fail;
}
curaddr->next = NULL;
if (addr != NULL) {
curaddr->addr = dup_sockaddr(addr, addr_size);
if (curaddr->addr == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
goto fail;
}
}
if (netmask != NULL) {
curaddr->netmask = dup_sockaddr(netmask, netmask_size);
if (curaddr->netmask == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
goto fail;
}
}
if (broadaddr != NULL) {
curaddr->broadaddr = dup_sockaddr(broadaddr, broadaddr_size);
if (curaddr->broadaddr == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
goto fail;
}
}
if (dstaddr != NULL) {
curaddr->dstaddr = dup_sockaddr(dstaddr, dstaddr_size);
if (curaddr->dstaddr == NULL) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
goto fail;
}
}
/*
* Find the end of the list of addresses.
*/
for (prevaddr = curdev->addresses; prevaddr != NULL;
prevaddr = nextaddr) {
nextaddr = prevaddr->next;
if (nextaddr == NULL) {
/*
* This is the end of the list.
*/
break;
}
}
if (prevaddr == NULL) {
/*
* The list was empty; this is the first member.
*/
curdev->addresses = curaddr;
} else {
/*
* "prevaddr" is the last member of the list; append
* this member to it.
*/
prevaddr->next = curaddr;
}
return (0);
fail:
if (curaddr != NULL) {
free(curaddr->addr);
free(curaddr->netmask);
free(curaddr->broadaddr);
free(curaddr->dstaddr);
free(curaddr);
}
return (-1);
}
/*
* 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 "getifaddrs()".
*/
int
pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
{
pcap_if_t *devlist = NULL;
struct ifaddrs *ifap, *ifa;
struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
size_t addr_size, broadaddr_size, dstaddr_size;
int ret = 0;
/*
* Get the list of interface addresses.
*
* Note: this won't return information about interfaces
* with no addresses; are there any such interfaces
* that would be capable of receiving packets?
* (Interfaces incapable of receiving packets aren't
* very interesting from libpcap's point of view.)
*
* LAN interfaces will probably have link-layer
* addresses; I don't know whether all implementations
* of "getifaddrs()" now, or in the future, will return
* those.
*/
if (getifaddrs(&ifap) != 0) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"getifaddrs: %s", pcap_strerror(errno));
return (-1);
}
for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
/*
* Is this interface up?
*/
if (!(ifa->ifa_flags & IFF_UP)) {
/*
* No, so don't add it to the list.
*/
continue;
}
/*
* "ifa_addr" was apparently null on at least one
* interface on some system.
*
* "ifa_broadaddr" may be non-null even on
* non-broadcast interfaces, and was null on
* at least one OpenBSD 3.4 system on at least
* one interface with IFF_BROADCAST set.
*
* "ifa_dstaddr" was, on at least one FreeBSD 4.1
* system, non-null on a non-point-to-point
* interface.
*
* Therefore, we supply the address and netmask only
* if "ifa_addr" is non-null (if there's no address,
* there's obviously no netmask), and supply the
* broadcast and destination addresses if the appropriate
* flag is set *and* the appropriate "ifa_" entry doesn't
* evaluate to a null pointer.
*/
if (ifa->ifa_addr != NULL) {
addr = ifa->ifa_addr;
addr_size = SA_LEN(addr);
netmask = ifa->ifa_netmask;
} else {
addr = NULL;
addr_size = 0;
netmask = NULL;
}
if (ifa->ifa_flags & IFF_BROADCAST &&
ifa->ifa_broadaddr != NULL) {
broadaddr = ifa->ifa_broadaddr;
broadaddr_size = SA_LEN(broadaddr);
} else {
broadaddr = NULL;
broadaddr_size = 0;
}
if (ifa->ifa_flags & IFF_POINTOPOINT &&
ifa->ifa_dstaddr != NULL) {
dstaddr = ifa->ifa_dstaddr;
dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
} else {
dstaddr = NULL;
dstaddr_size = 0;
}
/*
* Add information for this address to the list.
*/
if (add_addr_to_iflist(&devlist, ifa->ifa_name,
ifa->ifa_flags, addr, addr_size, netmask, addr_size,
broadaddr, broadaddr_size, dstaddr, dstaddr_size,
errbuf) < 0) {
ret = -1;
break;
}
}
freeifaddrs(ifap);
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);
}