Iwconfig

This is a module to work with the iwconfig command. Although iwconfig can be used to configure as well as query wireless interfaces, in this case I’ll just be using it to get information.

IwconfigEnum

A holder of constants so that users of this code will have a reference for the names used in the regular expressions.

IwconfigExpressions

The IwconfigExpressions holds the compiled regular expressions to tokenize the output of the iwconfig command.

IwconfigExpressions.essid	return:compiled regular expression to match the essid
IwconfigExpressions.mac_protocol	return:regex to match protocol (requires self.interface to be set)
IwconfigExpressions.mode	return:compiled regex to match the mode (e.g. Managed)
IwconfigExpressions.frequency	return:compiled regex to get the frequency
IwconfigExpressions.access_point	return:compiled regex to get the access point
IwconfigExpressions.bit_rate	return:expression to get the bit rate
IwconfigExpressions.tx_power	return:compiled regex to match the tx-power
IwconfigExpressions.link_quality	return:compiled regular expression to get the link quality
IwconfigExpressions.signal_level	return:compiled regex to get the signal level
IwconfigExpressions.rx_invalid_nwid	return:compiled regex to get count of invalid nwid
IwconfigExpressions.rx_invalid_crypt	return:compiled regex to get count of un-decryptable packets
IwconfigExpressions.rx_invalid_frag	return:compiled regex to get count of invalid packet fragments
IwconfigExpressions.tx_excessive_retries	return:compiled regex to get count of packets hardware failed to deliver
IwconfigExpressions.invalid_misc	return:compiled regex to get count of packets lost for misc reasons
IwconfigExpressions.missed_beacons	return:compiled regex to get count of beacons from Cell or AP missed

IwconfigQuery

Notes

According to the current (December 13, 2013) Ubuntu 13.10 man-page:

• ESSID identifies cells that are part of the same virtual network (all APs with the same ESSID)

• Access Point is the specific AP within the virtual network that the node is associated with

• mode can be one of:

  • Ad-Hoc (only one cell, no AP)
  • Managed (node cat connect to many APS (allows roaming))
  • Master (node acts as syncronization master or Access Point)
  • Repeater (forwards packets to other wireless nodes)
  • Secondary (acts as backup master/repeater)
  • Monitor (passively monitor all packets on the frequency (not associated with a cell))

• Bit Rate is the speed at which bits are transmitted (user speed lower due to congestion and overhead)

• RTS Threshold - threshold for handshake to make sure channel is clear (helps with congestion )

• fragmentation splits IP packet into smaller fragments to help with interference

• Rx invalid nwid is count of packets with different ESSID. Detects adjacent network on the same frequency.

• Tx excessive retries is the number of packets not delivered.

• Invalid misc is the number of packets lost for other wireless operations

• Missed beacon is number of periodic beacons from the AP missed. Usually indicates out of range.

The Model and API

IwconfigQuery(connection[, interface, ...])	Queries iwconfig for information
IwconfigQuery.event_timer	An EventTimer to track intervals between calling iwconfig
IwconfigQuery.output	Output of the iwconfig command, refreshed after self.interval second intervals
IwconfigQuery.command	return:command to send to connection to query iwconfig
IwconfigQuery.essid	return:the essid from the iwconfig command
IwconfigQuery.mac_protocol	return:the MAC protocol
IwconfigQuery.mode	return:the mode
IwconfigQuery.frequency	return:current frequency
IwconfigQuery.access_point	return:MAC address of associated AP
IwconfigQuery.bit_rate	return:bit-rate
IwconfigQuery.tx_power	return:the TX-power for the node
IwconfigQuery.link_quality	return:link-quality perceived by driver
IwconfigQuery.signal_level	return:signal level (RSSI)
IwconfigQuery.rx_invalid_nwid	return:count of packets with SSID’s not matching current cell
IwconfigQuery.rx_invalid_crypt	return:count of packets not unencryptable
IwconfigQuery.rx_invalid_frag	return:count of packets whose fragments couldn’t be re-assembled
IwconfigQuery.tx_excessive_retries	return:count of packets not successfully transmitted
IwconfigQuery.invalid_misc	return:count of invalid packets (received only?)
IwconfigQuery.missed_beacons	return:count of beacons not received
IwconfigQuery.__call__()	Calls the iwconfig command and returns the output
IwconfigQuery.__str__()	return:output of iwconfig command un-parsed
IwconfigQuery.check_errors(stderr)	Checks for known errors
IwconfigQuery.close()	Closes the event timer

Responsibilities

• maintains the expressions needed to parse the output of the iwconfig command
• issue command to connection
• returns requested values from the iwconfig output

Collaborators

• Connections