Check interface is up before connecting a NIO (Linux only). Fixes #277.

gns3server/modules/base_manager.py

@@ -28,6 +28,7 @@ import logging
 log = logging.getLogger(__name__)
 
 from uuid import UUID, uuid4
+from gns3server.utils.interfaces import is_interface_up
 from ..config import Config
 from ..utils.asyncio import wait_run_in_executor
 from .project_manager import ProjectManager
@@ -369,12 +370,17 @@ class BaseManager:
             nio = NIOUDP(lport, rhost, rport)
         elif nio_settings["type"] == "nio_tap":
             tap_device = nio_settings["tap_device"]
+            if not is_interface_up(tap_device):
+                raise aiohttp.web.HTTPConflict(text="TAP interface {} is down".format(tap_device))
             # FIXME: check for permissions on tap device
             # if not self._has_privileged_access(executable):
             #    raise aiohttp.web.HTTPForbidden(text="{} has no privileged access to {}.".format(executable, tap_device))
             nio = NIOTAP(tap_device)
         elif nio_settings["type"] == "nio_generic_ethernet":
-            nio = NIOGenericEthernet(nio_settings["ethernet_device"])
+            ethernet_device = nio_settings["ethernet_device"]
+            if not is_interface_up(ethernet_device):
+                raise aiohttp.web.HTTPConflict(text="Ethernet interface {} is down".format(ethernet_device))
+            nio = NIOGenericEthernet(ethernet_device)
         elif nio_settings["type"] == "nio_nat":
             nio = NIONAT()
         assert nio is not None

gns3server/modules/dynamips/__init__.py

@@ -32,7 +32,7 @@ import logging
 
 log = logging.getLogger(__name__)
 
-from gns3server.utils.interfaces import get_windows_interfaces
+from gns3server.utils.interfaces import get_windows_interfaces, is_interface_up
 from gns3server.utils.asyncio import wait_run_in_executor
 from pkg_resources import parse_version
 from uuid import UUID, uuid4
@@ -404,6 +404,8 @@ class Dynamips(BaseManager):
                     raise DynamipsError("Could not find interface {} on this host".format(ethernet_device))
                 else:
                     ethernet_device = npf_interface
+            if not is_interface_up(ethernet_device):
+                raise aiohttp.web.HTTPConflict(text="Ethernet interface {} is down".format(ethernet_device))
             nio = NIOGenericEthernet(node.hypervisor, ethernet_device)
         elif nio_settings["type"] == "nio_linux_ethernet":
             if sys.platform.startswith("win"):
@@ -412,6 +414,8 @@ class Dynamips(BaseManager):
             nio = NIOLinuxEthernet(node.hypervisor, ethernet_device)
         elif nio_settings["type"] == "nio_tap":
             tap_device = nio_settings["tap_device"]
+            if not is_interface_up(tap_device):
+                raise aiohttp.web.HTTPConflict(text="TAP interface {} is down".format(tap_device))
             nio = NIOTAP(node.hypervisor, tap_device)
         elif nio_settings["type"] == "nio_unix":
             local_file = nio_settings["local_file"]

gns3server/utils/interfaces.py

@@ -18,6 +18,8 @@
 
 import sys
 import aiohttp
+import socket
+import struct
 
 import logging
 log = logging.getLogger(__name__)
@@ -78,6 +80,31 @@ def get_windows_interfaces():
     return interfaces
 
 
+def is_interface_up(interface):
+    """
+    Checks if an interface is up.
+
+    :param interface: interface name
+
+    :returns: boolean
+    """
+
+    if sys.platform.startswith("linux"):
+        import fcntl
+        SIOCGIFFLAGS = 0x8913
+        try:
+            with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
+                result = fcntl.ioctl(s.fileno(), SIOCGIFFLAGS, interface + '\0' * 256)
+                flags, = struct.unpack('H', result[16:18])
+                if flags & 1:  # check if the up bit is set
+                    return True
+            return False
+        except OSError as e:
+            raise aiohttp.web.HTTPInternalServerError(text="Exception when checking if {} is up: {}".format(interface, e))
+    else:
+        #TODO: Windows & OSX support
+        return True
+
 def interfaces():
     """
     Gets the network interfaces on this server.