Fix FreeBSD tun handling with net.link.tun.devfs_cloning=0

Try to use SIOCIFCREATE to create an interface if it doesn't already exists.
Also try opening /dev/tun to get the next available device, before falling
back to the loop over tun0-tun255.

There is still strangeness here; sometimes the interface doesn't get an
IPv6 link-local address, and the IFDISABLED flag remains set.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/configure.ac b/configure.ac
index 8c7a292..3c42cb7 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -86,6 +86,7 @@ case $host_os in
     ;;
 esac
 
+AC_CHECK_FUNC(fdevname_r, [AC_DEFINE(HAVE_FDEVNAME_R, 1)], [])
 AC_CHECK_FUNC(getline, [AC_DEFINE(HAVE_GETLINE, 1)], [symver_getline="openconnect__getline;"])
 AC_CHECK_FUNC(strcasestr, [AC_DEFINE(HAVE_STRCASESTR, 1)], [])
 AC_CHECK_FUNC(asprintf, [AC_DEFINE(HAVE_ASPRINTF, 1)], [symver_asprintf="openconnect__asprintf;"])

diff --git a/tun.c b/tun.c
index 05f33e4..c000dbf 100644 (file)
--- a/tun.c
+++ b/tun.c
@@ -412,9 +412,37 @@ static int link_proto(int unit_nr, const char *devname, uint64_t flags)
 }
 #endif
 
+#ifdef SIOCIFCREATE
+static int bsd_open_tun(char *tun_name)
+{
+       int fd;
+       int s;
+       struct ifreq ifr;
+
+       fd = open(tun_name, O_RDWR);
+       if (fd >= 0) {
+               return fd;
+
+               s = socket(AF_INET, SOCK_DGRAM, 0);
+               if (s < 0)
+                       return -1;
+
+               memset(&ifr, 0, sizeof(ifr));
+               strncpy(ifr.ifr_name, tun_name + 5, sizeof(ifr.ifr_name) - 1);
+               if (!ioctl(s, SIOCIFCREATE, &ifr))
+                       fd = open(tun_name, O_RDWR);
+
+               close(s);
+       }
+       return fd;
+}
+#else
+#define bsd_open_tun(tun_name) open(tun_name, O_RDWR)
+#endif
+
 static int os_setup_tun(struct openconnect_info *vpninfo)
 {
-       int tun_fd;
+       int tun_fd = -1;
 
 #ifdef IFF_TUN /* Linux */
        struct ifreq ifr;
@@ -511,7 +539,7 @@ static int os_setup_tun(struct openconnect_info *vpninfo)
                }
                snprintf(tun_name, sizeof(tun_name),
                         "/dev/%s", vpninfo->ifname);
-               tun_fd = open(tun_name, O_RDWR);
+               tun_fd = bsd_open_tun(tun_name);
                if (tun_fd < 0) {
                        int err = errno;
                        vpn_progress(vpninfo, PRG_ERR,
@@ -519,10 +547,27 @@ static int os_setup_tun(struct openconnect_info *vpninfo)
                                     tun_name, strerror(err));
                        return -EINVAL;
                }
-       } else {
+       }
+#ifdef HAVE_FDEVNAME_R
+       /* We don't have to iterate over the possible devices; on FreeBSD
+          at least, opening /dev/tun will give us the next available
+          device. */
+       if (tun_fd < 0) {
+               tun_fd = open("/dev/tun", O_RDWR);
+               if (tun_fd >= 0) {
+                       if (!fdevname_r(tun_fd, tun_name, sizeof(tun_name)) ||
+                           strncmp(tun_name, "tun", 3)) {
+                               close(tun_fd);
+                               tun_fd = -1;
+                       } else
+                               vpninfo->ifname = strdup(tun_name);
+               }
+       }
+#endif
+       if (tun_fd < 0) {
                for (i = 0; i < 255; i++) {
                        sprintf(tun_name, "/dev/tun%d", i);
-                       tun_fd = open(tun_name, O_RDWR);
+                       tun_fd = bsd_open_tun(tun_name);
                        if (tun_fd >= 0)
                                break;
                }