mpm: xport: Let UDP manager re-enumerate available CHDR ifaces on init()

This will enumerate CHDR interfaces as late as possible, so that the
user changing the IP address will not affect operations. Note that IP
is considered static during a UHD session.

1 files changed, 23 insertions, 11 deletions

diff --git a/mpm/python/usrp_mpm/xports/xportmgr_udp.py b/mpm/python/usrp_mpm/xports/xportmgr_udp.py
index 18573bad9..0a7f19ffc 100644
--- a/mpm/python/usrp_mpm/xports/xportmgr_udp.py
+++ b/mpm/python/usrp_mpm/xports/xportmgr_udp.py
@@ -39,22 +39,19 @@ class XportMgrUDP(object):
         self.log.trace("Initializing UDP xport manager...")
         self._possible_chdr_ifaces = self.iface_config.keys()
         self.log.trace("Identifying available network interfaces...")
+        self.chdr_port = EthDispatcherTable.DEFAULT_VITA_PORT[0]
         self._chdr_ifaces = \
             self._init_interfaces(self._possible_chdr_ifaces)
-        self._eth_dispatchers = {
-            x: EthDispatcherTable(self.iface_config[x]['label'])
-            for x in self._chdr_ifaces
-        }
-        for ifname, table in iteritems(self._eth_dispatchers):
-            table.set_ipv4_addr(self._chdr_ifaces[ifname]['ip_addr'])
-        self.chdr_port = EthDispatcherTable.DEFAULT_VITA_PORT[0]
+        self._eth_dispatchers = {}
 
     def _init_interfaces(self, possible_ifaces):
         """
-        Initialize the list of network interfaces
+        Enumerate all network interfaces that are currently able to stream CHDR
+        Returns a dictionary iface name -> iface info, where iface info is the
+        return value of get_iface_info().
         """
         self.log.trace("Testing available interfaces out of `{}'".format(
-            possible_ifaces
+            list(possible_ifaces)
         ))
         valid_ifaces = net.get_valid_interfaces(possible_ifaces)
         if len(valid_ifaces):
@@ -66,12 +63,27 @@ class XportMgrUDP(object):
             for x in valid_ifaces
         }
 
+    def _update_dispatchers(self):
+        """
+        Updates the self._eth_dispatchers dictionary, makes sure that all IP
+        addresses are programmed correctly.
+
+        After calling this, _chdr_ifaces and _eth_dispatchers are in sync.
+        """
+        for iface in self._chdr_ifaces:
+            if iface not in self._eth_dispatchers:
+                self._eth_dispatchers[iface] = \
+                    EthDispatcherTable(self.iface_config[iface]['label'])
+        for ifname, table in iteritems(self._eth_dispatchers):
+            table.set_ipv4_addr(self._chdr_ifaces[ifname]['ip_addr'])
+
     def init(self, args):
         """
         Call this when the user calls 'init' on the periph manager
         """
-        # TODO re-run _init_interfaces, IP addresses could have changed since
-        # bootup
+        self._chdr_ifaces = \
+            self._init_interfaces(self._possible_chdr_ifaces)
+        self._update_dispatchers()
         for _, table in iteritems(self._eth_dispatchers):
             if 'forward_eth' in args or 'forward_bcast' in args:
                 table.set_forward_policy(