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;
struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
struct sockaddr *netmask, *broadaddr, *dstaddr;
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 get the entire interface list or fail to get it 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)
break;
free(buf);
buf_size *= 2;
}
ifrp = (struct ifreq *)buf;
ifend = (struct ifreq *)(buf + ifc.ifc_len);
for (; ifrp < ifend; ifrp = ifnext) {
n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
if (n < sizeof(*ifrp))
ifnext = ifrp + 1;
else
ifnext = (struct ifreq *)((char *)ifrp + n);
/*
* 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;
} 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;
/*
* 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;
} 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;
} else {
/*
* Not a broadcast interface, so no broadcast
* address.
*/
broadaddr = NULL;
}
/*
* 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;
} 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;
} else
dstaddr = NULL;
/*
* Add information for this address to the list.
*/
if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
ifrflags.ifr_flags, &ifrp->ifr_addr,
netmask, broadaddr, dstaddr, 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; add the "any" device,
* if we can open it.
*/
if (pcap_add_if(&devlist, "any", 0, any_descr, errbuf) < 0) {
/*
* Oops, we had a fatal error.
*/
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);
}
/*
* 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);
}
