void
__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
{
int fd = sockfd;
struct ifconf ifc;
int rq_len;
int nifs;
# define RQ_IFS 4
if (fd < 0)
fd = __opensock ();
if (fd < 0)
{
*num_ifs = 0;
*ifreqs = NULL;
return;
}
ifc.ifc_buf = NULL;
rq_len = RQ_IFS * sizeof (struct ifreq) / 2; /* Doubled in the loop. */
do
{
ifc.ifc_len = rq_len *= 2;
void *newp = realloc (ifc.ifc_buf, ifc.ifc_len);
if (newp == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0)
{
free (ifc.ifc_buf);
if (fd != sockfd)
__close (fd);
*num_ifs = 0;
*ifreqs = NULL;
return;
}
ifc.ifc_buf = newp;
}
while (rq_len < sizeof (struct ifreq) + ifc.ifc_len);
if (fd != sockfd)
__close (fd);
#ifdef _HAVE_SA_LEN
struct ifreq *ifr = *ifreqs;
nifs = 0;
while ((char *) ifr < ifc.ifc_buf + ifc.ifc_len)
{
++nifs;
ifr = __if_nextreq (ifr);
if (ifr == NULL)
break;
}
#else
nifs = ifc.ifc_len / sizeof (struct ifreq);
#endif
*num_ifs = nifs;
*ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq));
}
/* Create a linked list of `struct ifaddrs' structures, one for each
network interface on the host machine. If successful, store the
list in *IFAP and return 0. On errors, return -1 and set `errno'. */
int
getifaddrs (struct ifaddrs **ifap)
{
/* This implementation handles only IPv4 interfaces.
The various ioctls below will only work on an AF_INET socket.
Some different mechanism entirely must be used for IPv6. */
int fd = __socket (AF_INET, SOCK_DGRAM, 0);
struct ifreq *ifreqs;
int nifs;
if (fd < 0)
return -1;
__ifreq (&ifreqs, &nifs, fd);
if (ifreqs == NULL) /* XXX doesn't distinguish error vs none */
{
__close (fd);
return -1;
}
/* Now we have the list of interfaces and each one's address.
Put it into the expected format and fill in the remaining details. */
if (nifs == 0)
*ifap = NULL;
else
{
struct
{
struct ifaddrs ia;
struct sockaddr addr, netmask, broadaddr;
char name[IF_NAMESIZE];
} *storage;
struct ifreq *ifr;
int i;
storage = malloc (nifs * sizeof storage[0]);
if (storage == NULL)
{
__close (fd);
__if_freereq (ifreqs, nifs);
return -1;
}
i = 0;
ifr = ifreqs;
do
{
/* Fill in pointers to the storage we've already allocated. */
storage[i].ia.ifa_next = &storage[i + 1].ia;
storage[i].ia.ifa_addr = &storage[i].addr;
/* Now copy the information we already have from SIOCGIFCONF. */
storage[i].ia.ifa_name = strncpy (storage[i].name, ifr->ifr_name,
sizeof storage[i].name);
storage[i].addr = ifr->ifr_addr;
/* The SIOCGIFCONF call filled in only the name and address.
Now we must also ask for the other information we need. */
if (__ioctl (fd, SIOCGIFFLAGS, ifr) < 0)
break;
storage[i].ia.ifa_flags = ifr->ifr_flags;
ifr->ifr_addr = storage[i].addr;
if (__ioctl (fd, SIOCGIFNETMASK, ifr) < 0)
storage[i].ia.ifa_netmask = NULL;
else
{
storage[i].ia.ifa_netmask = &storage[i].netmask;
storage[i].netmask = ifr->ifr_netmask;
}
if (ifr->ifr_flags & IFF_BROADCAST)
{
ifr->ifr_addr = storage[i].addr;
if (__ioctl (fd, SIOCGIFBRDADDR, ifr) < 0)
storage[i].ia.ifa_broadaddr = NULL;
{
storage[i].ia.ifa_broadaddr = &storage[i].broadaddr;
storage[i].broadaddr = ifr->ifr_broadaddr;
}
}
else if (ifr->ifr_flags & IFF_POINTOPOINT)
{
ifr->ifr_addr = storage[i].addr;
if (__ioctl (fd, SIOCGIFDSTADDR, ifr) < 0)
storage[i].ia.ifa_broadaddr = NULL;
else
{
storage[i].ia.ifa_broadaddr = &storage[i].broadaddr;
storage[i].broadaddr = ifr->ifr_dstaddr;
}
}
else
storage[i].ia.ifa_broadaddr = NULL;
storage[i].ia.ifa_data = NULL; /* Nothing here for now. */
ifr = __if_nextreq (ifr);
} while (++i < nifs);
if (i < nifs) /* Broke out early on error. */
{
__close (fd);
free (storage);
__if_freereq (ifreqs, nifs);
return -1;
}
storage[i - 1].ia.ifa_next = NULL;
*ifap = &storage[0].ia;
__close (fd);
__if_freereq (ifreqs, nifs);
}
return 0;
}
void
__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
{
int fd = sockfd;
struct ifconf ifc;
int rq_len;
int nifs;
char *ifstart;
char *ifend;
struct ifreq *ifr;
/* FreeBSD has many interfaces, many of them are usually down. */
# define RQ_IFS 16
/* We have to assume all records are of limited size, so that we know
when we can stop enlarging the buffer. */
# define RQ_MAXSIZE 256
if (fd < 0)
fd = __opensock ();
if (fd < 0)
{
*num_ifs = 0;
*ifreqs = NULL;
return;
}
ifc.ifc_buf = NULL;
rq_len = RQ_IFS * sizeof (struct ifreq) + RQ_MAXSIZE;
for (;;)
{
ifc.ifc_len = rq_len;
ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
if (ifc.ifc_buf == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0)
{
if (ifc.ifc_buf)
free (ifc.ifc_buf);
if (fd != sockfd)
__close (fd);
*num_ifs = 0;
*ifreqs = NULL;
return;
}
if (ifc.ifc_len + RQ_MAXSIZE <= rq_len)
break;
rq_len *= 2;
}
nifs = 0;
ifstart = (char *) ifc.ifc_buf;
ifend = ifstart + ifc.ifc_len;
for (ifr = (struct ifreq *) ifstart;
(char *) ifr < ifend;
ifr = __if_nextreq (ifr))
nifs++;
if (fd != sockfd)
__close (fd);
*num_ifs = nifs;
*ifreqs = realloc (ifc.ifc_buf, ifc.ifc_len);
}
