def _set_opts(self):
"""Set scheduler-specific options based on heuristics."""
# Constants
MCLSHIFT = 11 # from /usr/src/sys/sys/param.h
MCLBYTES = 1 << MCLSHIFT # from /usr/src/sys/sys/param.h
RM_NS_PER_SEC = 1000000000 # from pfctl_altq.c
RM_FILTER_GAIN = 5 # from pfctl_altq.c
mtu, ifbw = getifmtu(self.ifname)
pktsize = ((mtu & ~MCLBYTES) if (mtu > MCLBYTES) else mtu)
maxpktsize = mtu
if pktsize > maxpktsize:
pktsize = maxpktsize
f = 0.0001
if self.bandwidth:
f = float(self.bandwidth) / self.ifbandwidth
if_ns_per_byte = (1.0 / self.ifbandwidth) * RM_NS_PER_SEC * 8
ns_per_byte = if_ns_per_byte / f
ptime = pktsize * if_ns_per_byte
cptime = ptime * (1.0 - f) / f
maxburst = (4 if (cptime > 10 * 1000000) else 16)
minburst = (2 if (maxburst >= 2) else maxburst)
z = 1 << RM_FILTER_GAIN
g = 1.0 - (1.0 / z)
gton = g ** maxburst
gtom = g ** (minburst -1)
maxidle = ((1.0 / f - 1.0) * ((1.0 - gton) / gton))
maxidle_s = 1.0 - g
maxidle = ptime * (maxidle if (maxidle > maxidle_s) else maxidle_s)
offtime = cptime * (1.0 + 1.0 / (1.0 - g) * (1.0 - gtom) / gtom)
minidle = -(maxpktsize * ns_per_byte)
maxidle = ((maxidle*8.0) / ns_per_byte) * (2 ** RM_FILTER_GAIN)
offtime = ((offtime*8.0) / ns_per_byte) * (2 ** RM_FILTER_GAIN)
minidle = ((minidle*8.0) / ns_per_byte) * (2 ** RM_FILTER_GAIN)
self.opts["minburst"] = minburst
self.opts["maxburst"] = maxburst
self.opts["pktsize"] = pktsize
self.opts["maxpktsize"] = maxpktsize
self.opts["ns_per_byte"] = int(ns_per_byte)
self.opts["maxidle"] = int(abs(maxidle / 1000.0))
self.opts["minidle"] = int(minidle / 1000.0)
self.opts["offtime"] = int(abs(offtime / 1000.0))
def __init__(self, altq=None, **kw):
"""Check argument and initialize class attributes.
'altq' can be either a pfaltq structure or a string with the name of
the queue.
"""
if isinstance(altq, basestring):
kw["qname"] = altq
if altq is None or isinstance(altq, basestring):
altq = pf_altq(qlimit=DEFAULT_QLIMIT, priority=DEFAULT_PRIORITY)
super(PFAltq, self).__init__(altq, **kw)
if not self.ifname:
raise PFError("Interface name not specified")
mtu, ifbw = getifmtu(self.ifname)
if not self.ifbandwidth:
if not ifbw:
raise PFError("No ifbandwidth for interface " +
"'{.ifname}'".format(self))
self.ifbandwidth = ifbw
if not self.qname and not self.parent:
# This is a root ALTQ discipline
self.bandwidth = 0
self.priority = 0
if not self.tbrsize:
self.tbrsize = mtu * 24
if self.ifbandwidth <= 1 * 1000 * 1000:
self.tbrsize = mtu
elif self.ifbandwidth <= 4 * 1000 * 1000:
self.tbrsize = mtu * 4
elif self.ifbandwidth <= 8 * 1000 * 1000:
self.tbrsize = mtu * 8