initial commit

nova/compute/linux_net.py

@@ -0,0 +1,146 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+import signal
+import os
+import nova.utils
+import subprocess
+
+# todo(ja): does the definition of network_path belong here?
+
+from nova import flags
+FLAGS=flags.FLAGS
+
+def execute(cmd):
+    if FLAGS.fake_network:
+        print "FAKE NET: %s" % cmd
+        return "fake", 0
+    else:
+        nova.utils.execute(cmd)
+
+def runthis(desc, cmd):
+    if FLAGS.fake_network:
+        execute(cmd)
+    else:
+        nova.utils.runthis(desc,cmd)
+
+def Popen(cmd):
+    if FLAGS.fake_network:
+        execute(' '.join(cmd))
+    else:
+        subprocess.Popen(cmd)
+
+
+def device_exists(device):
+    (out, err) = execute("ifconfig %s" % device)
+    return not err
+
+def confirm_rule(cmd):
+    execute("sudo iptables --delete %s" % (cmd))
+    execute("sudo iptables -I %s" % (cmd))
+
+def remove_rule(cmd):
+    execute("sudo iptables --delete %s" % (cmd))
+
+def bind_public_ip(ip, interface):
+    runthis("Binding IP to interface: %s", "sudo ip addr add %s dev %s" % (ip, interface))
+
+def vlan_create(net):
+    """ create a vlan on on a bridge device unless vlan already exists """
+    if not device_exists("vlan%s" % net.vlan):
+        execute("sudo vconfig set_name_type VLAN_PLUS_VID_NO_PAD")
+        execute("sudo vconfig add %s %s" % (net.bridge_dev, net.vlan))
+        execute("sudo ifconfig vlan%s up" % (net.vlan))
+
+def bridge_create(net):
+    """ create a bridge on a vlan unless it already exists """
+    if not device_exists(net.bridge_name):
+        execute("sudo brctl addbr %s" % (net.bridge_name))
+        # execute("sudo brctl setfd %s 0" % (net.bridge_name))
+        # execute("sudo brctl setageing %s 10" % (net.bridge_name))
+        execute("sudo brctl stp %s off" % (net.bridge_name))
+        execute("sudo brctl addif %s vlan%s" % (net.bridge_name, net.vlan))
+        if net.bridge_gets_ip:
+            execute("sudo ifconfig %s %s broadcast %s netmask %s up" % \
+                (net.bridge_name, net.gateway, net.broadcast, net.netmask))
+            confirm_rule("FORWARD --in-interface %s -j ACCEPT" % (net.bridge_name))
+        else:
+            execute("sudo ifconfig %s up" % net.bridge_name)
+
+def dnsmasq_cmd(net):
+    cmd = ['sudo dnsmasq',
+        ' --strict-order',
+        ' --bind-interfaces',
+        ' --conf-file=',
+        ' --pid-file=%s' % dhcp_file(net.vlan, 'pid'),
+        ' --listen-address=%s' % net.dhcp_listen_address,
+        ' --except-interface=lo',
+        ' --dhcp-range=%s,%s,120s' % (net.dhcp_range_start, net.dhcp_range_end),
+        ' --dhcp-lease-max=61',
+        ' --dhcp-hostsfile=%s' % dhcp_file(net.vlan, 'conf'),
+        ' --dhcp-leasefile=%s' % dhcp_file(net.vlan, 'leases')]
+    return ''.join(cmd)
+
+def hostDHCP(network, host):
+    idx = host['address'].split(".")[-1] # Logically, the idx of instances they've launched in this net
+    return "%s,%s-%s-%s.novalocal,%s" % \
+        (host['mac'], host['user_id'], network.vlan, idx, host['address'])
+
+# todo(ja): if the system has restarted or pid numbers have wrapped
+#           then you cannot be certain that the pid refers to the
+#           dnsmasq.  As well, sending a HUP only reloads the hostfile,
+#           so any configuration options (like dchp-range, vlan, ...)
+#           aren't reloaded
+def start_dnsmasq(network):
+    """ (re)starts a dnsmasq server for a given network
+
+    if a dnsmasq instance is already running then send a HUP
+    signal causing it to reload, otherwise spawn a new instance
+    """
+    with open(dhcp_file(network.vlan, 'conf'), 'w') as f:
+        for host_name in network.hosts:
+            f.write("%s\n" % hostDHCP(network, network.hosts[host_name]))
+
+    pid = dnsmasq_pid_for(network)
+
+    # if dnsmasq is already running, then tell it to reload
+    if pid:
+        # todo(ja): use "/proc/%d/cmdline" % (pid) to determine if pid refers
+        #           correct dnsmasq process
+        try:
+            os.kill(pid, signal.SIGHUP)
+            return
+        except Exception, e:
+            logging.debug("Killing dnsmasq threw %s", e)
+
+    # otherwise delete the existing leases file and start dnsmasq
+    lease_file = dhcp_file(network.vlan, 'leases')
+    if os.path.exists(lease_file):
+        os.unlink(lease_file)
+
+    Popen(dnsmasq_cmd(network).split(" "))
+
+def stop_dnsmasq(network):
+    """ stops the dnsmasq instance for a given network """
+    pid = dnsmasq_pid_for(network)
+
+    if pid:
+        os.kill(pid, signal.SIGTERM)
+
+def dhcp_file(vlan, kind):
+    """ return path to a pid, leases or conf file for a vlan """
+
+    return os.path.abspath("%s/nova-%s.%s" % (FLAGS.networks_path, vlan, kind))
+
+def dnsmasq_pid_for(network):
+    """ the pid for prior dnsmasq instance for a vlan,
+    returns None if no pid file exists
+
+    if machine has rebooted pid might be incorrect (caller should check)
+    """
+
+    pid_file = dhcp_file(network.vlan, 'pid')
+
+    if os.path.exists(pid_file):
+        with open(pid_file, 'r') as f:
+            return int(f.read())
+