# $Id$
# $URL$

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

import logger
import subprocess
import sioc
import re
import vserver
import os

dryrun=0
setup_link_cmd="/usr/share/vini/setup-egre-link"
teardown_link_cmd="/usr/share/vini/teardown-egre-link"
ifaces = {}
old_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)
    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("%s: Set up virtual link to node %d" % (slice, 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(key, nodeid):
    logger.log("topo: Tear down virtual link %sx%s" % (key, nodeid))
    run(teardown_link_cmd + " %s %s" % (nodeid, key))
    return


"""
Called for all active virtual link interfaces, so they won't be cleaned up.
"""
def refresh_virtual_link(nodeid, key):
    try:
        name = "d%sx%s" % (key, nodeid)
        del old_ifaces[name]
    except:
        pass


"""
Clean up old virtual links (e.g., to nodes that have been deleted 
from the slice).
"""
def clean_up_old_virtual_links():
    pattern = "d(.*)x(.*)"
    for iface in old_ifaces:
        m = re.match(pattern, iface)
        if m:
            key = int(m.group(1))
            node = int(m.group(2))
            teardown_virtual_link(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, netns):
    topolist = convert_topospec_to_list(topospec)
    for (nodeid,ipaddr,rate) in topolist:
        if not virtual_link(key, nodeid):
            if netns:
                setup_virtual_link(slice, key, rate, myid, nodeid, ipaddr)
        else:
            logger.log("%s: virtual link to node %s exists" % (slice, nodeid))
            refresh_virtual_link(nodeid, key)

"""
Write /etc/vservers/<slicename>/spaces/net
"""
def writeConf(slicename, value):
    SLICEDIR="/etc/vservers/%s/" % slicename
    SPACESDIR="%s/spaces/" % SLICEDIR
    if os.path.exists(SLICEDIR):
        if not os.path.exists(SPACESDIR):
            try:
                os.mkdir(SPACESDIR)
            except os.error:
                logger.log("netns: could not create %s\n" % SPACESDIR)
                return
        f = open("%s/net" % SPACESDIR, "w")
        f.write("%s\n" % value)
        f.close()
        STATUS="OFF"
        if int(value) >= 1:
            STATUS="ON"
        logger.log("%s: network namespace %s\n" % (slicename, STATUS))


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.

Creating the virtual link depends on the contents of 
/etc/vservers/<slice>/spaces/net.  Update this first.
"""
def GetSlivers(data):
    global ifaces, old_ifaces
    ifaces = old_ifaces = sioc.gifconf()

    for sliver in data['slivers']:
        attrs = {}
        for attribute in sliver['attributes']:
            attrs[attribute['name']] = attribute['value']
        if 'netns' in attrs:
            writeConf(sliver['name'], attrs['netns'])
            netns = attrs['netns']
        else:
            netns = 0

        try:
            if vserver.VServer(sliver['name']).is_running():
                if 'egre_key' in attrs and 'topo_rspec' in attrs:
                    logger.log("topo: Update topology for slice %s" % \
                                   sliver['name'])
                    update(sliver['name'], data['node_id'], 
                           attrs['topo_rspec'], attrs['egre_key'], netns)
        except:
            logger.log("topo: sliver %s not running yet. Deferring." % \
                           sliver['name'])

    clean_up_old_virtual_links()