Get McsToRate function working again.
Only lightly tested, but I think it's about right.
diff --git a/wifimon.py b/wifimon.py
index 3565462..1961242 100755
--- a/wifimon.py
+++ b/wifimon.py
@@ -32,8 +32,14 @@
class Flags(object):
"""Flags in the radiotap header."""
- # TODO(apenwarr): add the other flags here
- BAD_MCS = 0x40
+ CFP = 0x01
+ SHORT_PREAMBLE = 0x02
+ WEP = 0x04
+ FRAGMENTATION = 0x08
+ FCS = 0x10
+ DATA_PAD = 0x20
+ BAD_FCS = 0x40
+ SHORT_GI = 0x80
RADIOTAP_FIELDS = [
@@ -181,14 +187,8 @@
]
-def McsToRate(tb):
- """Given an MCS (known,flags) tuple, return the corresponding bitrate."""
- # known=tb[0]
- # flags=tb[1]
- # ********************************************
- # ************* currently broken code here ***
- # ************ FIXME FIXME FIXME FIXME *******
- # ********************************************
+def McsToRate(known, flags, index):
+ """Given MCS information for a packet, return the corresponding bitrate."""
if known & (1 << 0):
bw = (20, 40, 20, 20)[flags & 0x3]
else:
@@ -198,7 +198,7 @@
else:
gi = 0
if known & (1 << 1):
- mcs = tb[2]
+ mcs = index
else:
mcs = 0
if bw == 20:
@@ -235,10 +235,10 @@
opt = Struct({})
# pcap packet header
- bytes = stream.read(16)
- if len(bytes) < 16: break # EOF
+ pcaphdr = stream.read(16)
+ if len(pcaphdr) < 16: break # EOF
(ts_sec, ts_usec,
- incl_len, orig_len) = struct.unpack(byteorder + 'IIII', bytes)
+ incl_len, orig_len) = struct.unpack(byteorder + 'IIII', pcaphdr)
if incl_len > orig_len:
raise ValueError('packet incl_len(%d) > orig_len(%d): invalid'
% (incl_len, orig_len))
@@ -263,11 +263,11 @@
optbytes = radiotap[8:it_len]
ofs = 0
- for i, (name, format) in enumerate(RADIOTAP_FIELDS):
+ for i, (name, structformat) in enumerate(RADIOTAP_FIELDS):
if it_present & (1 << i):
- ofs = Align(ofs, struct.calcsize(format[0]))
- sz = struct.calcsize(format)
- v = struct.unpack(format, optbytes[ofs:ofs + sz])
+ ofs = Align(ofs, struct.calcsize(structformat[0]))
+ sz = struct.calcsize(structformat)
+ v = struct.unpack(structformat, optbytes[ofs:ofs + sz])
if name == 'mac_usecs':
opt.mac_usecs = v[0]
# opt.mac_secs = v[0] / 1e6
@@ -275,8 +275,11 @@
opt.freq = v[0]
opt.channel_flags = v[1]
elif name == 'ht':
+ ht_known, ht_flags, ht_index = v
opt.ht = v
- opt.mcs = v[2]
+ opt.mcs = ht_index
+ opt.rate = McsToRate(ht_known, ht_flags, ht_index)
+ opt.spatialstreams = MCS_TABLE[ht_index][0]
else:
opt[name] = v if len(v) > 1 else v[0]
ofs += sz
@@ -328,7 +331,7 @@
ts = 0
print (ts, opt)
# print HexDump(frame)
- elif 1:
+ elif 0:
want_fields = [
'ta',
'ra',
@@ -376,7 +379,7 @@
continue
if 'mcs' in opt:
print(
- src, opt.dsmode, opt.typestr, ts, McsToRate(opt.mcs), mac_usecs,
+ src, opt.dsmode, opt.typestr, ts, opt.rate, mac_usecs,
opt.orig_len, seq, opt.flags)
else:
print(
