/* Determine protocol families for which interfaces exist. Linux version.
- Copyright (C) 2003 Free Software Foundation, Inc.
+ Copyright (C) 2003-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+#include <assert.h>
#include <errno.h>
#include <ifaddrs.h>
#include <netdb.h>
+#include <stddef.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
+#include <stdint.h>
#include <sys/socket.h>
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
-#include "kernel-features.h"
+#include <not-cancel.h>
+#include <libc-lock.h>
+#include <atomic.h>
+#include <nscd/nscd-client.h>
+#include "netlinkaccess.h"
-static int
-make_request (int fd, pid_t pid, bool *seen_ipv4, bool *seen_ipv6)
+#ifndef IFA_F_HOMEADDRESS
+# define IFA_F_HOMEADDRESS 0
+#endif
+#ifndef IFA_F_OPTIMISTIC
+# define IFA_F_OPTIMISTIC 0
+#endif
+
+
+struct cached_data
{
- struct
+ uint32_t timestamp;
+ uint32_t usecnt;
+ bool seen_ipv4;
+ bool seen_ipv6;
+ size_t in6ailen;
+ struct in6addrinfo in6ai[0];
+};
+
+static struct cached_data noai6ai_cached =
+ {
+ .usecnt = 1, /* Make sure we never try to delete this entry. */
+ .in6ailen = 0
+ };
+
+static struct cached_data *cache;
+__libc_lock_define_initialized (static, lock);
+
+
+#if IS_IN (nscd)
+static uint32_t nl_timestamp;
+
+uint32_t
+__bump_nl_timestamp (void)
+{
+ if (atomic_increment_val (&nl_timestamp) == 0)
+ atomic_increment (&nl_timestamp);
+
+ return nl_timestamp;
+}
+#endif
+
+static inline uint32_t
+get_nl_timestamp (void)
+{
+#if IS_IN (nscd)
+ return nl_timestamp;
+#elif defined USE_NSCD
+ return __nscd_get_nl_timestamp ();
+#else
+ return 0;
+#endif
+}
+
+static inline bool
+cache_valid_p (void)
+{
+ if (cache != NULL)
+ {
+ uint32_t timestamp = get_nl_timestamp ();
+ return timestamp != 0 && cache->timestamp == timestamp;
+ }
+ return false;
+}
+
+
+static struct cached_data *
+make_request (int fd, pid_t pid)
+{
+ struct cached_data *result = NULL;
+
+ size_t result_len = 0;
+ size_t result_cap = 32;
+
+ struct req
{
struct nlmsghdr nlh;
struct rtgenmsg g;
+ /* struct rtgenmsg consists of a single byte. This means there
+ are three bytes of padding included in the REQ definition.
+ We make them explicit here. */
+ char pad[3];
} req;
struct sockaddr_nl nladdr;
req.nlh.nlmsg_seq = time (NULL);
req.g.rtgen_family = AF_UNSPEC;
+ assert (sizeof (req) - offsetof (struct req, pad) == 3);
+ memset (req.pad, '\0', sizeof (req.pad));
+
memset (&nladdr, '\0', sizeof (nladdr));
nladdr.nl_family = AF_NETLINK;
+#ifdef PAGE_SIZE
+ const size_t buf_size = PAGE_SIZE;
+#else
+ const size_t buf_size = 4096;
+#endif
+ char buf[buf_size];
+
+ struct iovec iov = { buf, buf_size };
+
if (TEMP_FAILURE_RETRY (__sendto (fd, (void *) &req, sizeof (req), 0,
(struct sockaddr *) &nladdr,
sizeof (nladdr))) < 0)
- return -1;
-
- *seen_ipv4 = false;
- *seen_ipv6 = false;
+ goto out_fail;
bool done = false;
- char buf[4096];
- struct iovec iov = { buf, sizeof (buf) };
+
+ bool seen_ipv4 = false;
+ bool seen_ipv6 = false;
do
{
};
ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0));
+ __netlink_assert_response (fd, read_len);
if (read_len < 0)
- return -1;
+ goto out_fail;
if (msg.msg_flags & MSG_TRUNC)
- return -1;
+ goto out_fail;
struct nlmsghdr *nlmh;
for (nlmh = (struct nlmsghdr *) buf;
if (nlmh->nlmsg_type == RTM_NEWADDR)
{
struct ifaddrmsg *ifam = (struct ifaddrmsg *) NLMSG_DATA (nlmh);
+ struct rtattr *rta = IFA_RTA (ifam);
+ size_t len = nlmh->nlmsg_len - NLMSG_LENGTH (sizeof (*ifam));
+
+ if (ifam->ifa_family != AF_INET
+ && ifam->ifa_family != AF_INET6)
+ continue;
+
+ const void *local = NULL;
+ const void *address = NULL;
+ while (RTA_OK (rta, len))
+ {
+ switch (rta->rta_type)
+ {
+ case IFA_LOCAL:
+ local = RTA_DATA (rta);
+ break;
+
+ case IFA_ADDRESS:
+ address = RTA_DATA (rta);
+ goto out;
+ }
+
+ rta = RTA_NEXT (rta, len);
+ }
+
+ if (local != NULL)
+ {
+ address = local;
+ out:
+ if (ifam->ifa_family == AF_INET)
+ {
+ if (*(const in_addr_t *) address
+ != htonl (INADDR_LOOPBACK))
+ seen_ipv4 = true;
+ }
+ else
+ {
+ if (!IN6_IS_ADDR_LOOPBACK (address))
+ seen_ipv6 = true;
+ }
+ }
- switch (ifam->ifa_family)
+ if (result_len == 0 || result_len == result_cap)
{
- case AF_INET:
- *seen_ipv4 = true;
- break;
- case AF_INET6:
- *seen_ipv6 = true;
- break;
- default:
- /* Ignore. */
- break;
+ result_cap = 2 * result_cap;
+ result = realloc (result, sizeof (*result)
+ + result_cap
+ * sizeof (struct in6addrinfo));
}
+
+ if (!result)
+ goto out_fail;
+
+ struct in6addrinfo *info = &result->in6ai[result_len++];
+
+ info->flags = (((ifam->ifa_flags
+ & (IFA_F_DEPRECATED | IFA_F_OPTIMISTIC))
+ ? in6ai_deprecated : 0)
+ | ((ifam->ifa_flags & IFA_F_HOMEADDRESS)
+ ? in6ai_homeaddress : 0));
+ info->prefixlen = ifam->ifa_prefixlen;
+ info->index = ifam->ifa_index;
+ if (ifam->ifa_family == AF_INET)
+ {
+ info->addr[0] = 0;
+ info->addr[1] = 0;
+ info->addr[2] = htonl (0xffff);
+ info->addr[3] = *(const in_addr_t *) address;
+ }
+ else
+ memcpy (info->addr, address, sizeof (info->addr));
}
else if (nlmh->nlmsg_type == NLMSG_DONE)
/* We found the end, leave the loop. */
done = true;
- else ;
}
}
while (! done);
- __close (fd);
+ if (seen_ipv6 && result != NULL)
+ {
+ result->timestamp = get_nl_timestamp ();
+ result->usecnt = 2;
+ result->seen_ipv4 = seen_ipv4;
+ result->seen_ipv6 = true;
+ result->in6ailen = result_len;
+ }
+ else
+ {
+ free (result);
- return 0;
-}
+ atomic_add (&noai6ai_cached.usecnt, 2);
+ noai6ai_cached.seen_ipv4 = seen_ipv4;
+ noai6ai_cached.seen_ipv6 = seen_ipv6;
+ result = &noai6ai_cached;
+ }
+ return result;
-/* We don't know if we have NETLINK support compiled in in our
- Kernel. */
-#if __ASSUME_NETLINK_SUPPORT == 0
-/* Define in ifaddrs.h. */
-extern int __no_netlink_support attribute_hidden;
-#else
-# define __no_netlink_support 0
-#endif
+ out_fail:
+
+ free (result);
+ return NULL;
+}
void
attribute_hidden
-__check_pf (bool *seen_ipv4, bool *seen_ipv6)
+__check_pf (bool *seen_ipv4, bool *seen_ipv6,
+ struct in6addrinfo **in6ai, size_t *in6ailen)
{
- if (! __no_netlink_support)
+ *in6ai = NULL;
+ *in6ailen = 0;
+
+ struct cached_data *olddata = NULL;
+ struct cached_data *data = NULL;
+
+ __libc_lock_lock (lock);
+
+ if (cache_valid_p ())
+ {
+ data = cache;
+ atomic_increment (&cache->usecnt);
+ }
+ else
{
int fd = __socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
- struct sockaddr_nl nladdr;
- memset (&nladdr, '\0', sizeof (nladdr));
- nladdr.nl_family = AF_NETLINK;
+ if (__glibc_likely (fd >= 0))
+ {
+ struct sockaddr_nl nladdr;
+ memset (&nladdr, '\0', sizeof (nladdr));
+ nladdr.nl_family = AF_NETLINK;
- socklen_t addr_len = sizeof (nladdr);
+ socklen_t addr_len = sizeof (nladdr);
- if (fd >= 0
- && __bind (fd, (struct sockaddr *) &nladdr, sizeof (nladdr)) == 0
- && __getsockname (fd, (struct sockaddr *) &nladdr, &addr_len) == 0
- && make_request (fd, nladdr.nl_pid, seen_ipv4, seen_ipv6) == 0)
- /* It worked. */
- return;
+ if (__bind (fd, (struct sockaddr *) &nladdr, sizeof (nladdr)) == 0
+ && __getsockname (fd, (struct sockaddr *) &nladdr,
+ &addr_len) == 0)
+ data = make_request (fd, nladdr.nl_pid);
- if (fd >= 0)
- __close (fd);
+ close_not_cancel_no_status (fd);
+ }
-#if __ASSUME_NETLINK_SUPPORT == 0
- /* Remember that there is no netlink support. */
- __no_netlink_support = 1;
-#else
- /* We cannot determine what interfaces are available. Be
- pessimistic. */
- *seen_ipv4 = true;
- *seen_ipv6 = true;
-#endif
+ if (data != NULL)
+ {
+ olddata = cache;
+ cache = data;
+ }
}
-#if __ASSUME_NETLINK_SUPPORT == 0
- /* No netlink. Get the interface list via getifaddrs. */
- struct ifaddrs *ifa = NULL;
- if (getifaddrs (&ifa) != 0)
+ __libc_lock_unlock (lock);
+
+ if (data != NULL)
{
- /* We cannot determine what interfaces are available. Be
- pessimistic. */
- *seen_ipv4 = true;
- *seen_ipv6 = true;
+ /* It worked. */
+ *seen_ipv4 = data->seen_ipv4;
+ *seen_ipv6 = data->seen_ipv6;
+ *in6ailen = data->in6ailen;
+ *in6ai = data->in6ai;
+
+ if (olddata != NULL && olddata->usecnt > 0
+ && atomic_add_zero (&olddata->usecnt, -1))
+ free (olddata);
+
return;
}
- *seen_ipv4 = false;
- *seen_ipv6 = false;
+ /* We cannot determine what interfaces are available. Be
+ pessimistic. */
+ *seen_ipv4 = true;
+ *seen_ipv6 = true;
+}
- struct ifaddrs *runp;
- for (runp = ifa; runp != NULL; runp = runp->ifa_next)
- if (runp->ifa_addr->sa_family == PF_INET)
- *seen_ipv4 = true;
- else if (runp->ifa_addr->sa_family == PF_INET6)
- *seen_ipv6 = true;
+/* Free the cache if it has been allocated. */
+libc_freeres_fn (freecache)
+{
+ if (cache)
+ __free_in6ai (cache->in6ai);
+}
- (void) freeifaddrs (ifa);
-#endif
+void
+__free_in6ai (struct in6addrinfo *ai)
+{
+ if (ai != NULL)
+ {
+ struct cached_data *data =
+ (struct cached_data *) ((char *) ai
+ - offsetof (struct cached_data, in6ai));
+
+ if (atomic_add_zero (&data->usecnt, -1))
+ {
+ __libc_lock_lock (lock);
+
+ if (data->usecnt == 0)
+ /* Still unused. */
+ free (data);
+
+ __libc_lock_unlock (lock);
+ }
+ }
}
projects / thirdparty / glibc.git / blobdiff