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Diffstat (limited to 'sysdeps/unix/sysv/linux/check_native.c')
-rw-r--r--sysdeps/unix/sysv/linux/check_native.c209
1 files changed, 209 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/check_native.c b/sysdeps/unix/sysv/linux/check_native.c
new file mode 100644
index 0000000000..9b1bb61941
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/check_native.c
@@ -0,0 +1,209 @@
+/* Determine whether interfaces use native transport.  Linux version.
+   Copyright (C) 2007 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
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   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.  */
+
+#include <assert.h>
+#include <errno.h>
+#include <ifaddrs.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <sys/ioctl.h>
+
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <not-cancel.h>
+
+
+void
+__check_native (uint32_t a1_index, int *a1_native,
+		uint32_t a2_index, int *a2_native)
+{
+  int fd = __socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+
+  struct sockaddr_nl nladdr;
+  memset (&nladdr, '\0', sizeof (nladdr));
+  nladdr.nl_family = AF_NETLINK;
+
+  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)
+    return;
+
+  pid_t pid = nladdr.nl_pid;
+  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;
+
+  req.nlh.nlmsg_len = sizeof (req);
+  req.nlh.nlmsg_type = RTM_GETLINK;
+  req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
+  req.nlh.nlmsg_pid = 0;
+  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
+  /* Help the compiler optimize out the malloc call if PAGE_SIZE
+     is constant and smaller or equal to PTHREAD_STACK_MIN/4.  */
+  const size_t buf_size = PAGE_SIZE;
+#else
+  const size_t buf_size = __getpagesize ();
+#endif
+  bool use_malloc = false;
+  char *buf;
+
+  if (__libc_use_alloca (buf_size))
+    buf = alloca (buf_size);
+  else
+    {
+      buf = malloc (buf_size);
+      if (buf != NULL)
+	use_malloc = true;
+      else
+	goto out_fail;
+    }
+
+  struct iovec iov = { buf, buf_size };
+
+  if (TEMP_FAILURE_RETRY (__sendto (fd, (void *) &req, sizeof (req), 0,
+				    (struct sockaddr *) &nladdr,
+				    sizeof (nladdr))) < 0)
+    goto out_fail;
+
+  bool done = false;
+  int v4fd = -1;
+  do
+    {
+      struct msghdr msg =
+	{
+	  (void *) &nladdr, sizeof (nladdr),
+	  &iov, 1,
+	  NULL, 0,
+	  0
+	};
+
+      ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0));
+      if (read_len < 0)
+	goto out_fail;
+
+      if (msg.msg_flags & MSG_TRUNC)
+	goto out_fail;
+
+      struct nlmsghdr *nlmh;
+      for (nlmh = (struct nlmsghdr *) buf;
+	   NLMSG_OK (nlmh, (size_t) read_len);
+	   nlmh = (struct nlmsghdr *) NLMSG_NEXT (nlmh, read_len))
+	{
+	  if (nladdr.nl_pid != 0 || (pid_t) nlmh->nlmsg_pid != pid
+	      || nlmh->nlmsg_seq != req.nlh.nlmsg_seq)
+	    continue;
+
+	  if (nlmh->nlmsg_type == RTM_NEWLINK)
+	    {
+	      /* A RTM_NEWLINK message can have IFLA_STATS data. We need to
+		 know the size before creating the list to allocate enough
+		 memory.  */
+	      struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlmh);
+	      struct rtattr *rta = IFLA_RTA (ifim);
+	      size_t rtasize = IFLA_PAYLOAD (nlmh);
+	      int index = ifim->ifi_index;
+
+	      if (a1_index == index || a2_index == index)
+		while (RTA_OK (rta, rtasize))
+		  {
+		    char *rta_data = RTA_DATA (rta);
+		    size_t rta_payload = RTA_PAYLOAD (rta);
+
+		    if (rta->rta_type == IFLA_IFNAME)
+		      {
+			struct ifreq ifr;
+			*((char *) mempcpy (ifr.ifr_name, rta_data,
+					    rta_payload))= '\0';
+
+			if (v4fd == -1)
+			  {
+			    v4fd = __socket (AF_INET, SOCK_DGRAM, 0);
+			    if (v4fd == -1)
+			      return;
+			  }
+
+			if (__ioctl (v4fd, SIOCGIFHWADDR, &ifr) >= 0)
+			  {
+			    int native
+			      = (ifr.ifr_hwaddr.sa_family != ARPHRD_TUNNEL6
+				 && ifr.ifr_hwaddr.sa_family != ARPHRD_TUNNEL
+				 && ifr.ifr_hwaddr.sa_family != ARPHRD_SIT);
+
+			    if (a1_index == index)
+			      {
+				*a1_native = native;
+				a1_index = 0xffffffffu;
+			      }
+			    if (a2_index == index)
+			      {
+				*a2_native = native;
+				a2_index = 0xffffffffu;
+			      }
+
+			    if (a1_index == 0xffffffffu
+				&& a2_index == 0xffffffffu)
+			      goto out;
+			  }
+			break;
+		      }
+
+		    rta = RTA_NEXT (rta, rtasize);
+		  }
+	    }
+	  else if (nlmh->nlmsg_type == NLMSG_DONE)
+	    /* We found the end, leave the loop.  */
+	    done = true;
+	}
+    }
+  while (! done);
+
+ out:
+  close_not_cancel_no_status (fd);
+  if (v4fd != -1)
+    close_not_cancel_no_status (v4fd);
+
+  return;
+
+out_fail:
+  if (use_malloc)
+    free (buf);
+}