X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-dhcp.git/blobdiff_plain/2bf0733f2f07804fbdc6c5f3efbd06d6c0e0ffa7..149df324e6f1aca5ba2f043dba6614c65b499968:/invirt-dhcpserver diff --git a/invirt-dhcpserver b/invirt-dhcpserver index e803ecd..20a0816 100755 --- a/invirt-dhcpserver +++ b/invirt-dhcpserver @@ -1,4 +1,5 @@ #!/usr/bin/python +import os.path import sys import pydhcplib import pydhcplib.dhcp_network @@ -12,6 +13,8 @@ from Queue import Queue from threading import Thread from subprocess import PIPE, Popen import netifaces as ni +sys.path.append('/usr/lib/xen-default/lib/python/') +from xen.lowlevel import xs import syslog as s @@ -22,10 +25,43 @@ from invirt.config import structs as config dhcp_options = {'domain_name_server': ','.join(config.dhcp.dns), 'ip_address_lease_time': config.dhcp.get('leasetime', 60*60*24)} +class Interfaces(object): + @staticmethod + def primary_ip(name): + """primary_ip returns an interface's primary IP address. + + This is the first IPv4 address returned by "ip addr show $name" + """ + # TODO(quentin): The netifaces module is a pile of crappy C. + # Figure out a way to do this in native Python. + return ni.ifaddresses(name)[ni.AF_INET][0]['addr'] + + @staticmethod + def exists(name): + """exists checks if an interface exists. + + Args: + name: Interface name + """ + return os.path.exists("/sys/class/net/"+name) + + class DhcpBackend: def __init__(self, queue): database.connect() self.queue = queue + self.main_ip = Interfaces.primary_ip(config.xen.iface) + def add_route_and_arp(self, ip, intf, gateway): + try: + p = Popen(['ip', 'route', 'add', ip, 'dev', intf, 'src', self.main_ip, 'metric', '2' if intf.startswith('vif') else '1'], stdout=PIPE, stderr=PIPE) + (out, err) = p.communicate() + if p.returncode == 0: + s.syslog(s.LOG_INFO, "Added route for IP %s to interface %s" % (ip, intf)) + self.queue.put((ip, gateway)) + sys.stderr.write(err) + sys.stdout.write(out) + except Exception as e: + s.syslog(s.LOG_ERR, "Could not add route for IP %s: %s" % (ip, e)) def findNIC(self, mac): database.clear_cache() return database.NIC.query.filter_by(mac_addr=mac).first() @@ -42,6 +78,38 @@ class DhcpBackend: if parts[1] == ipstr: s.syslog(s.LOG_DEBUG, "find_interface found "+str(nic.ip)+" on "+parts[0]) return parts[0] + # Either the machine isn't running, or the route is missing. We can + # fix the latter. + try: + xsc = xs.xs() + domid = xsc.read('', '/vm/%s/device/vif/0/frontend-id' % (nic.machine.uuid)) + # If we didn't find the domid, the machine is either off or the + # UUID in xenstore isn't right. Try slightly harder. + if not domid: + for uuid in xsc.ls('', '/vm'): + if xsc.read('', '/vm/%s/name' % (uuid)) == 'd_' + nic.machine.name: + domid = xsc.read('', '/vm/%s/device/vif/0/frontend-id' % (uuid)) + if not domid: + xsc.close() + return None + for vifnum in xsc.ls('', '/local/domain/0/backend/vif/%s' % (domid)): + if xsc.read('', '/local/domain/0/backend/vif/%s/%s/mac' % (domid, vifnum)) == nic.mac_addr: + # Prefer the tap if it exists; paravirtualized HVMs will + # have already unplugged it, so if it's there, it's the one + # in use. + for viftype in ('tap', 'vif'): + vif = '%s%s.%s' % (viftype, domid, vifnum) + if Interfaces.exists(vif): + self.add_route_and_arp(nic.ip, vif, nic.gateway) + xsc.close() + return vif + xsc.close() + except Exception as e: + try: + xsc.close() + except Exception as e2: + s.syslog(s.LOG_ERR, "Could not close connection to xenstore: %s" % (e2)) + s.syslog(s.LOG_ERR, "Could not find interface and add missing route: %s" % (e)) return None def getParameters(self, **extra): @@ -149,7 +217,6 @@ class DhcpBackend: s.syslog(s.LOG_INFO,"Ack ip "+str(yiaddr)+" for "+str(chaddr)) n = self.findNIC(str(chaddr)) intf = self.find_interface_by_nic(n) - main_ip = ni.ifaddresses(config.xen.iface)[ni.AF_INET][0]['addr'] s.syslog(s.LOG_ERR, "Interface is %s" % (intf)) # Don't perform "other" actions if the machine isn't running other_action = n.other_action if n.other_action and intf else '' @@ -171,16 +238,7 @@ class DhcpBackend: # IP needs to be added. Just try adding both of them, and # arp for whichever of them turns out to be new. for parms in [(n.ip, n.gateway), (n.other_ip, n.other_gateway)]: - try: - p = Popen(['ip', 'route', 'add', parms[0], 'dev', intf, 'src', main_ip, 'metric', '2' if intf.startswith('vif') else '1'], stdout=PIPE, stderr=PIPE) - (out, err) = p.communicate() - if p.returncode == 0: - s.syslog(s.LOG_INFO, "Added route for IP %s to interface %s" % (parms[0], intf)) - self.queue.put(parms) - sys.stderr.write(err) - sys.stdout.write(out) - except Exception as e: - s.syslog(s.LOG_ERR, "Could not add route for IP %s: %s" % (parms[0], e)) + self.add_route_and_arp(parms[0], intf, parms[1]) try: # iptables will let you add the same rule again and again; # let's not do that. @@ -355,7 +413,7 @@ class ArpspoofWorker(Thread): while True: (ip, gw) = self.queue.get() try: - p = Popen(['timeout', '5', 'arpspoof', '-i', self.iface, '-t', gw, ip], stdout=PIPE, stderr=PIPE) + p = Popen(['timeout', '-s', 'KILL', '5', 'arpspoof', '-i', self.iface, '-t', gw, ip], stdout=PIPE, stderr=PIPE) (out, err) = p.communicate() if p.returncode != 124: s.syslog(s.LOG_ERR, "arpspoof returned %s for IP %s gateway %s" % (p.returncode, ip, gw))