# $Id$
# $URL$

""" 
VINI/Trellis NodeManager plugin.
Create virtual links from the topo_rspec slice attribute. 
"""

import logger
import subprocess
import sioc
import re

dryrun=0
setup_link_cmd="/usr/share/vini/setup-egre-link"
teardown_link_cmd="/usr/share/vini/teardown-egre-link"
ifaces = {}

def run(cmd):
    if dryrun:
        logger.log(cmd)
        return -1
    else:
        return subprocess.call(cmd, shell=True);


"""
Check for existence of interface d<key>x<nodeid>
"""
def virtual_link(key, nodeid):
    name = "d%sx%s" % (key, nodeid)
    # logger.log("Looking for iface %s" % name)
    if name in ifaces:
        return True
    else:
        return False


"""
Create a "virtual link" for slice between here and nodeid.
The key is used to create the EGRE tunnel.
"""
def setup_virtual_link(slice, key, rate, myid, nodeid, ipaddr):
    logger.log("Set up virtual link to node %d" % nodeid)
    if myid < nodeid:
        virtip = "10.%d.%d.2" % (myid, nodeid)
    else:
        virtip = "10.%d.%d.3" % (nodeid, myid)
        
    run(setup_link_cmd + " %s %s %s %s %s %s" % (slice, nodeid, ipaddr, 
                                                 key, rate, virtip))
    return


"""
Tear down the "virtual link" for slice between here and nodeid.
"""
def teardown_virtual_link(slice, key, nodeid):
    logger.log("Tear down virtual link to node %s" % nodeid)
    run(teardown_link_cmd + " %s %s %s" % (slice, nodeid, key))
    return


"""
Clean up old virtual links (e.g., to nodes that have been deleted 
from the slice).
"""
def clean_up_old_virtual_links(slice, key, nodelist):
    pattern = "d%sx(.*)" % key
    for iface in ifaces:
        m = re.match(pattern, iface)
        if m:
            node = int(m.group(1))
            if not node in nodelist:
                logger.log("%s" % nodelist)
                teardown_virtual_link(slice, key, node)


"""
Not the safest thing to do, probably should use pickle() or something.
"""
def convert_topospec_to_list(rspec):
    return eval(rspec)


"""
Update virtual links for the slice
"""
def update(slice, myid, topospec, key):
    topolist = convert_topospec_to_list(topospec)
    nodelist=[]
    for (nodeid,ipaddr,rate) in topolist:
        nodelist.append(nodeid)
        if not virtual_link(key, nodeid):
            setup_virtual_link(slice, key, rate, myid, nodeid, ipaddr)
        else:
            logger.log("Virtual link to node %s exists" % nodeid)

    clean_up_old_virtual_links(slice, key, nodelist)


def start(options, config):
    pass


"""
Update the virtual links for a sliver if it has a 'netns' attribute,
an 'egre_key' attribute, and a 'topo_rspec' attribute.
"""
def GetSlivers(data):
    global ifaces
    ifaces = sioc.gifconf()

    for sliver in data['slivers']:
        attrs = {}
        for attribute in sliver['attributes']:
            attrs[attribute['name']] = attribute['value']
        if 'netns' in attrs and 'egre_key' in attrs and 'topo_rspec' in attrs:
            if attrs['netns'] > 0:
                logger.log("Update topology for slice %s" % sliver['name'])
                update(sliver['name'], data['node_id'], 
                       attrs['topo_rspec'], attrs['egre_key'])