int nn_iface_resolve (const char *addr, size_t addrlen, int ipv4only,
struct sockaddr_storage *result, size_t *resultlen)
{
int rc;
int s;
struct ifreq req;
/* Asterisk is a special name meaning "all interfaces". */
if (addrlen == 1 && addr [0] == '*') {
nn_iface_any (ipv4only, result, resultlen);
return 0;
}
/* Open the helper socket. */
#ifdef SOCK_CLOEXEC
s = socket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
#else
s = socket (AF_INET, SOCK_DGRAM, 0);
#endif
errno_assert (s != -1);
/* Create the interface name resolution request. */
if (sizeof (req.ifr_name) <= addrlen) {
nn_closefd (s);
return -ENODEV;
}
memcpy (req.ifr_name, addr, addrlen);
req.ifr_name [addrlen] = 0;
/* Execute the request. */
rc = ioctl (s, SIOCGIFADDR, (caddr_t) &req, sizeof (struct ifreq));
if (rc == -1) {
nn_closefd (s);
return -ENODEV;
}
/* Interface name resolution succeeded. Return the address to the user. */
/* TODO: What about IPv6 addresses? */
nn_assert (req.ifr_addr.sa_family == AF_INET);
if (result)
memcpy (result, (struct sockaddr_in*) &req.ifr_addr,
sizeof (struct sockaddr_in));
if (resultlen)
*resultlen = sizeof (struct sockaddr_in);
nn_closefd (s);
return 0;
}
/* The last resort case. If we haven't found any mechanism for turning
NIC names into addresses, we'll try to resolve the string as an address
literal. */
int nn_iface_resolve (const char *addr, size_t addrlen, int ipv4only,
struct sockaddr_storage *result, size_t *resultlen)
{
int rc;
/* Asterisk is a special name meaning "all interfaces". */
if (addrlen == 1 && addr [0] == '*') {
nn_iface_any (ipv4only, result, resultlen);
return 0;
}
/* On Windows there are no sane network interface names. We'll treat the
name as a IP address literal. */
rc = nn_literal_resolve (addr, addrlen, ipv4only, result, resultlen);
if (rc == -EINVAL)
return -ENODEV;
errnum_assert (rc == 0, -rc);
return 0;
}
int nn_iface_resolve (const char *addr, size_t addrlen, int ipv4only,
struct sockaddr_storage *result, size_t *resultlen)
{
int rc;
struct ifaddrs *ifaces;
struct ifaddrs *it;
struct ifaddrs *ipv4;
struct ifaddrs *ipv6;
size_t ifalen;
/* Asterisk is a special name meaning "all interfaces". */
if (addrlen == 1 && addr [0] == '*') {
nn_iface_any (ipv4only, result, resultlen);
return 0;
}
/* Try to resolve the supplied string as a literal address. */
rc = nn_literal_resolve (addr, addrlen, ipv4only, result, resultlen);
if (rc == 0)
return 0;
errnum_assert (rc == -EINVAL, -rc);
/* Get the list of local network interfaces from the system. */
ifaces = NULL;
rc = getifaddrs (&ifaces);
errno_assert (rc == 0);
nn_assert (ifaces);
/* Find the NIC with the specified name. */
ipv4 = NULL;
ipv6 = NULL;
for (it = ifaces; it != NULL; it = it->ifa_next) {
if (!it->ifa_addr)
continue;
ifalen = strlen (it->ifa_name);
if (ifalen != addrlen || memcmp (it->ifa_name, addr, addrlen) != 0)
continue;
switch (it->ifa_addr->sa_family) {
case AF_INET:
nn_assert (!ipv4);
ipv4 = it;
break;
case AF_INET6:
nn_assert (!ipv6);
ipv6 = it;
break;
}
}
/* IPv6 address is preferable. */
if (ipv6 && !ipv4only) {
if (result) {
result->ss_family = AF_INET6;
memcpy (result, ipv6->ifa_addr, sizeof (struct sockaddr_in6));
}
if (resultlen)
*resultlen = sizeof (struct sockaddr_in6);
freeifaddrs (ifaces);
return 0;
}
/* Use IPv4 address. */
if (ipv4) {
if (result) {
result->ss_family = AF_INET;
memcpy (result, ipv4->ifa_addr, sizeof (struct sockaddr_in));
}
if (resultlen)
*resultlen = sizeof (struct sockaddr_in);
freeifaddrs (ifaces);
return 0;
}
/* There's no such interface. */
freeifaddrs (ifaces);
return -ENODEV;
}
