Remus: python netlink fixes

Fix deprecation warning in Qdisc class under python 2.6.
Fix rtattr length and padding (rta_len is unaligned).
Null-terminate qdisc name in rtnl messages.

Signed-off-by: Brendan Cully <brendan@cs.ubc.ca>

tools/python/xen/remus/netlink.py

@@ -1,5 +1,7 @@
 # netlink wrappers
 
+# See include/linux/netlink.h and rtnetlink.h
+
 import socket, struct
 import xen.lowlevel.netlink
 
@@ -77,9 +79,9 @@ class rtattr(object):
         return align(self.rta_len)
 
     def pack(self):
-        self.rta_len = self.fmtlen + align(len(self.body), 2)
+        self.rta_len = self.fmtlen + len(self.body)
         s = struct.pack(self.fmt, self.rta_len, self.rta_type) + self.body
-        pad = self.rta_len - len(s)
+        pad = align(self.rta_len) - len(s)
         if pad:
             s += '\0' * pad
         return s
@@ -127,14 +129,16 @@ class nlmsg(object):
         attr.rta_type = type
         attr.body = data
         self.rta += attr.pack()
+        self.nlmsg_len = len(self)
 
     def settype(self, cmd):
         self.nlmsg_type = cmd
 
     def pack(self):
-        return struct.pack(self.fmt, len(self), self.nlmsg_type,
+        s = struct.pack(self.fmt, len(self), self.nlmsg_type,
                            self.nlmsg_flags, self.nlmsg_seq,
                            self.nlmsg_pid) + self.body + self.rta
+        return s
 
     def unpack(self, msg):
         args = struct.unpack(self.fmt, msg[:self.fmtlen])

tools/python/xen/remus/qdisc.py

@@ -35,7 +35,7 @@ class addrequest(request):
         flags = netlink.NLM_F_EXCL|netlink.NLM_F_CREATE
         super(addrequest, self).__init__(netlink.RTM_NEWQDISC, flags=flags,
                                          dev=dev, handle=handle)
-        self.n.addattr(netlink.TCA_KIND, qdisc.kind)
+        self.n.addattr(netlink.TCA_KIND, qdisc.kind + '\0')
         opts = qdisc.pack()
         if opts:
             self.n.addattr(netlink.TCA_OPTIONS, opts)
@@ -49,7 +49,7 @@ class changerequest(request):
     def __init__(self, dev, handle, qdisc):
         super(changerequest, self).__init__(netlink.RTM_NEWQDISC,
                                             dev=dev, handle=handle)
-        self.n.addattr(netlink.TCA_KIND, qdisc.kind)
+        self.n.addattr(netlink.TCA_KIND, qdisc.kind + '\0')
         opts = qdisc.pack()
         if opts:
             self.n.addattr(netlink.TCA_OPTIONS, opts)
@@ -59,7 +59,7 @@ class Qdisc(object):
         if qdict:
             kind = qdict.get('kind')
             cls = qdisc_kinds.get(kind, cls)
-        obj = super(Qdisc, cls).__new__(cls, qdict=qdict, *args, **opts)
+        obj = super(Qdisc, cls).__new__(cls)
         return obj
 
     def __init__(self, qdict):