Weird APs have single integer Quality instead of x/100, which network.py barfs on

[darryllee]

So in the attached iwlist.out file, you'll see one of my neighbors APs (grr, crappy AT&T router) has a Quality of 40, instead of the expected 72/100 or 48/100.

Apparently network.py never expected such lame access points, but instead of just setting Quality to 12, it falls through, and it gets set to your default of '', which then breaks the sortNetworks function, which really wants to find a slash and do some division.

I wrote a workaround: #197

But I think it'd be better to figure out why it's not able to get the single integer Quality from these lame APs (I'm not seeing any other places where it's looking for a / or a 100), but maybe this will help somebody who's also running into this problem.

Also, I'm using a super-cheap Sabrent dongle, in case that matters. But the iwlist scan runs fine on it, so I think it's these weird APs that is throwing things off.

[darryllee]

iwlist output:
iwlist.txt

wlan0     Scan completed :
      Cell 01 - Address: 80:37:73:FA:17:CF
                ESSID:"ATTKcVsCFA_EXT"
                Protocol:IEEE 802.11bgn
                Mode:Master
                Frequency:2.437 GHz (Channel 6)
                Encryption key:on
                Bit Rates:144 Mb/s
                Extra:wpa_ie=dd1a0050f20101000050f20202000050f2020050f20401000050f202
                IE: WPA Version 1
                    Group Cipher : TKIP
                    Pairwise Ciphers (2) : TKIP CCMP
                    Authentication Suites (1) : PSK
                Extra:rsn_ie=30180100000fac020200000fac02000fac040100000fac020000
                IE: IEEE 802.11i/WPA2 Version 1
                    Group Cipher : TKIP
                    Pairwise Ciphers (2) : TKIP CCMP
                    Authentication Suites (1) : PSK
                IE: Unknown: DD8D0050F204104A0001101044000102103B000103104700102880288028801880A880803773FA17CF102100044E54475210230008574E3330303052501024000256321042000C3830333737336661313763661054000800060050F204000110110017574E333030305250763228576972656C6573732041502910080002210C103C0001011049000600372A000120
                Quality:40  Signal level:0  Noise level:0
      Cell 02 - Address: C0:FF:D4:8C:00:00
                ESSID:"NETGEAR21"
                Protocol:IEEE 802.11bgn
                Mode:Master
                Frequency:2.462 GHz (Channel 11)
                Encryption key:on
                Bit Rates:144 Mb/s
                Extra:rsn_ie=30140100000fac040100000fac040100000fac020c00
                IE: IEEE 802.11i/WPA2 Version 1
                    Group Cipher : CCMP
                    Pairwise Ciphers (1) : CCMP
                    Authentication Suites (1) : PSK
                IE: Unknown: DD750050F204104A0001101044000102103B00010310470010000000000000000000000000000000001021000D4E4554474541522C20496E632E10230007565A433330303010240007565A43333030301042000230311054000800060050F2040001101100064E5447524253100800020084103C000101
                Quality=72/100  Signal level=65/100  
      Cell 03 - Address: FA:8F:CA:30:4B:15
                ESSID:""
                Protocol:IEEE 802.11bgn
                Mode:Master
                Frequency:2.462 GHz (Channel 11)
                Encryption key:off
                Bit Rates:72 Mb/s
                Quality=36/100  Signal level=44/100  
      Cell 04 - Address: 94:10:3E:7E:80:D6
                ESSID:"Slinkys"
                Protocol:IEEE 802.11bgn
                Mode:Master
                Frequency:2.462 GHz (Channel 11)
                Encryption key:on
                Bit Rates:300 Mb/s
                Extra:wpa_ie=dd160050f20101000050f20201000050f20201000050f202
                IE: WPA Version 1
                    Group Cipher : TKIP
                    Pairwise Ciphers (1) : TKIP
                    Authentication Suites (1) : PSK
                Extra:rsn_ie=30140100000fac020100000fac040100000fac020000
                IE: IEEE 802.11i/WPA2 Version 1
                    Group Cipher : TKIP
                    Pairwise Ciphers (1) : CCMP
                    Authentication Suites (1) : PSK
                IE: Unknown: DD8F0050F204104A0001101044000102103B00010310470010C353B453693C0133919DC0F7523D283F1021000C4C696E6B7379732C204C4C4310230009575254313930304143102400095752543139303041431042000E31334A31303630383431363839371054000800060050F204000110110007536C696E6B797310080002200C103C0001011049000600372A000120
                Quality=58/100  Signal level=69/100  

[darryllee]

I'm (not enough of a Python hacker|too damn lazy/old) to figure out why the old parse routines are broken, but somebody else has recently written a new parser: https://github.com/jsh2134/iw_parse/

And it appears to have originated out of a request on a Raspberry Pi forum, so hey, that's worth looking into, I would think: https://www.raspberrypi.org/forums/viewtopic.php?f=32&t=85601

[darryllee]

Ok, to be fair, looking at the iwlist code, it's not necessarily the AP to blame, but rather an inconsistency in how iwlist formats Quality/Signal/Noise statistics if it can't read the range:

From wireless_tools.29/iwlib.c:

/* We can't read the range, so we don't know... */
  snprintf(buffer, buflen,
           "Quality:%d  Signal level:%d  Noise level:%d",
           qual->qual, qual->level, qual->noise);