iwd/TODO

Background
==========

- Priority scale: High, Medium and Low

- Complexity scale: C1, C2, C4 and C8.  The complexity scale is exponential,
  with complexity 1 being the lowest complexity.  Complexity is a function
  of both task 'complexity' and task 'scope'.

  The general rule of thumb is that a complexity 1 task should take 1-2 weeks
  for a person very familiar with the codebase.  Higher complexity tasks
  require more time and have higher uncertainty.

  Higher complexity tasks should be refined into several lower complexity tasks
  once the task is better understood.


mac80211_hwsim
==============

- Add support for HWSIM_CMD_SET_RADIO command

  To allow modifying an existing radio, add the HWSIM_CMD_SET_RADIO.  The
  first possible feature should be to emulate the hardware RFKILL switch.

  It might be required to add a HWSIM_ATTR_RADIO_HW_RFKILL attribute flag
  to the HWSIM_CMD_NEW_RADIO to enable virtual radios with a hardware
  level RFKILL switch.

  Priority: Medium
  Complexity: C1

- Allow configuration of MAC address or list of MAC addresses

  The radios are auto-generating a fake MAC address.  It would be useful
  to allow specifying a MAC address to be used.  In certain cases it might
  be also useful to provide a list of MAC addresses so that for example
  with secondary interfaces these can be used.

  Priority: Low
  Complexity: C2

- Move mac80211_hwsim.h header file to UAPI includes

  The mac80211_hwsim.h is the public API description of this netlink
  interface and thus it should be provided via UAPI includes.

  For this work work the mac80211_hwsim.h header needs to be modified
  so that it also compiles from userspace.  At the moment it throws
  errors.  And it needs to become part of the UAPI headers of the
  Linux kernel.

  In addition it should provide HWSIM_GENL_NAME that provides the
  generic netlink "MAC82011_HWSIM" family string.

  Priority: Low
  Complexity: C1

- Provide kernel option to allow defining the number of initial radios

  By default the mac80211_hwsim modules creates 2 radios by default unless
  it is overwritten with the radios=x module parameter.

  To allow loading the mac80211_hwsim by default and even with accidental
  loading of the module, it would be good to provide a kernel configuration
  option that allows changing the default value here.

  For our testing we want to load mac80211_hwsim without any radios. Maybe
  this should be the default for the new kernel option.

  If the default of initial radios can be changed to zero, then it is also
  possible to add MODULE_ALIAS_GENL_FAMILY to support auto-loading of
  the mac80211_hwsim kernel module.

  Priority: Low
  Complexity: C1

- New configuration options for radios

  At the moment the radios created are all equal and feature rich.  However
  for testing we want to create radios with different emulated hardware
  capabilities.  Provide new attributes or flags that allow enabling or
  disabling certain mac80211 features.

  For example AP mode, P2P mode, number of interface combinations, TDLS
  support, number of Scan SSIDs, supported ciphers and so on.

  Priority: Low
  Complexity: C2


Wireless monitor
================

- Add support for PACKET_RECV_OUTPUT socket option of AF_PACKET

  Instead of having to switch every interface manually into promiscuous
  mode, it would be useful to set PACKET_RECV_OUTPUT to receive also
  the traffic that leaves the system.

  This would make tracing PAE / EAPoL traffic easy and provides better
  sniffing capabilities.

  Unfortunately, PACKET_RECV_OUTPUT logic is not implemented at all in
  the kernel. So, first implement it in the kernel, and then use it in
  nlmon.c as a set_sockopt option.

  Priority: Low
  Complexity: C8

- Subscribe to all nl80211 multicast groups at startup

  It seems the nlmon packets are limited to actual subscribed mutlicast
  groups.  To get a complete picture of all the nl80211 commands and
  events, it is required that iwmon adds membership to all multicast
  groups that the nl80211 lists.

  This means that the netlink socket used for resolving nl80211 family
  name needs to be kept open and actively processed since it will also
  receive these multicast events.  However the event itself can be dropped
  since the one from nlmon with the proper kernel level timestamps should
  be taken into account.

  An alternative is to fix the netlink_deliver_tap() function in the
  kernel netlink layer to not be affected by the broadcast filtering.

  Priority: Medium
  Complexity: C1

- Print the 'group' of the decoded message

  Whenever an event / message is received, iwmon should print the genl
  group of the message (e.g. mlme, scan, config, regulatory).  This will
  make it easier to add handling of such events / commands inside iwd.

  Priority: Medium
  Complexity: C1


Wireless simulator
==================

- Add support for builtin wireless access point emulator

  When creating a pair of mac80211_hwsim radios, allow one to operate as
  access point.  The hwsim utility will emulate the access point on the
  second interface for as long as it is running.  Which means that from
  the first interface it is possible to scan and connect to this access
  point using standard wireless tools (including iwd and iwctl).

  Code for the AP mode can be shared from iwd feature for access point
  operation once that has been implemented.

  Priority: Medium
  Complexity: C8


Wireless daemon
===============

- Let EAP methods configure timeouts

  Different EAP methods might have different recommendations for various
  timeouts.  E.g. retransmit timeout, overall timeout, etc.  The EAP framework
  should be updated to enable EAP methods to configure these timeouts
  accordingly.  A sane default should also be provided.

  Priority: High
  Complexity: C2

- EAPoL should take EAP timeouts into consideration

  EAPoL state machine currently uses its own (very short) timeout for the
  4-Way handshake / session key generation.  This timeout does not take into
  account the fact that EAP authentication might need to be performed first.

  Priority: High
  Complexity: C1

- Add unit test data with 2nd RSNE in Authenticator 3/4 message

  The specification allows the AP to send a second RSN element in its 4-way
  handshake message 3/4.  Find some test data for this case and create a unit
  test case.

  Priority: Low
  Complexity: C1

- Handle "Use group cipher suite" option for pairwise ciphers

  If the AP specifies "Use group cipher suite" as its only pairwise suite, then
  handle this appropriately inside EAPoL handshaking code.  The install_gtk
  callback might need to be modified to handle this case.

  Priority: Low
  Complexity: C1

- Add support for PMK Caching from 802.11-2007.  This is sometimes referred to
  as "fast, secure roam back".  Essentially the client caches PMKIDs generated
  when connecting to various APs.  If the client roams back to an AP that has
  already been connected to, and the PMK is cached by both, then the 802.1X
  exchange can be skipped.

  Priority: Low
  Complexity: C4

- Add support for Opportunistic Key Caching (OKC).  This is not defined by
  any 802.11 standards, but is made available by major vendors such as Cisco
  and Microsoft.

  Priority: Low
  Complexity: C4

- Add support for Direct Link Setup from 802.11e.

  Priority: Low
  Complexity: C8

- Add support for Automatic Power Save Delivery (APSD).  This includes
  scheduled (s-APSD) and unscheduled (u-APSD).  This will require rudimentary
  support of WMM protocol.  This feature was introduced in 802.11e.

  Priority: Low
  Complexity: C4

- Add support for Fast BSS Transition (FT) from 802.11r.  FT over air is
  already supported by iwd.  Add support for 'FT over DS'. In FT over DS,
  action frames can be used to perform a 4-way handshake to the target AP
  while still connected to the current AP.

  Priority: Low
  Complexity: C4

- Add support for 802.11u.  This is required for Passpoint 2.0 support.

  Priority: Low
  Complexity: C8

- Add support for Wireless Network Management (WNM) from 802.11v.  Parts of
  this are needed for Passpoint support.

  Priority: Low
  Complexity: C8

- Add support for Tunneled Direct Link Setup (TDLS) from 802.11z.

  Priority: Medium
  Complexity: C8

- Add support for the STK 4-Way Handshake into eapol.c as described in
  802.11-2016 Setion 12.7.

  Priority: Medium
  Complexity: C8

- Add support for WiFi P2P.  This tasks depends on 'STK 4-Way Handshake' task.
  iwd will require a new P2P D-Bus API to be exposed in order for clients to
  manage P2P connections.  P2P specific logic for device management and
  switching between P2P and STA/AP modes for a particular interface will be
  required.

  Priority: Medium
  Complexity: C8

- Add support for EAP-LEAP.  This is a Cisco proprietary EAP method that is
  quite widespread.

  Priority: Medium
  Complexity: C4

- Add support for EAP-OTP.  OTP stands for 'One Time Password' and can be
  found in RFC3784.

  Priority: Low
  Complexity: C4

- Take EAP MSK size into consideration.

  MSK is mandated to be 64 bytes long, and depending on the AKM, different parts
  of the MSK are used to generate keys.  Some EAP methods produce MSKs with less
  than 64 bytes of useable data.  For example, LEAP produces only 16 bytes and
  MSCHAPv2 produces 32 bytes.  If the AKM requires MSK of a certain size, and
  the EAP method does not provide enough data, then the handshake should be
  aborted.

  Priority: Medium
  Complexity: C2

- Implement Enrollee Session Overlap Detection after WSC Protocol Run

  WSC Best Practices v2.0.1, Section 3.15 describes an enhacement to detect
  PBC session overlaps.  The Enrollee is asked to perform an extra scan without
  the PBC request in the ProbeRequest frames after EAP-WSC completes
  successfully.  If another AP in PBC mode is found, then a SessionOverlap
  error should be reported to the user.

  Priority: Low
  Complexity: C2

- Implement 4-Address mode when acting as a client

  NL80211 allows one to use 4-address mode in STA role.  In this case the
  EAPoL packets flow over the bridge interface while the rest of the commands
  are addressed to the actual interface index.  This can be useful to share
  the WiFi interface over various VM instances.

  Priority: Low
  Complexity: C2

- Use NL80211_CMD_CRIT_PROTOCOL_START / CRIT_PROTOCOL_STOP

  Research whether iwd should be making use of these commands in order to
  make EAP & 4-way handshakes, as well as DHCP exchanges more reliable.

  Priority: Medium
  Complexity: C2

- DPP Support

  Device Provisioning Protocol is a new specification from WiFi Alliance.
  This allows devices to be provisioned, typically via a QR code.

  Priority: Low
  Complexity: C8

- OWE Support

  Opportunistic Wireless Encryption described in RFC 8110 provides a way for
  open networks to be encrypted.  No authentication is provided, only
  encryption

  Priority: Low
  Complexity: C8

- iwctl should register the agent even in non-interactive mode

  When iwctl is started in non-interactive mode it currently does not register
  the agent.  This can lead to a .NoAgent error being reported when issuing
  commands through iwctl in this mode.  This behavior is generally okay for PSK
  networks that only require the agent on the first connection.  For 802.1x
  networks the Agent can be used to obtain username/password/passphrase details
  and thus used much more often.  Make sure that iwctl supports this possibility
  even in non-interactive mode.

  Priority: High
  Complexity: C1

- Implement GTK & corresponding group cipher suite options for AP / Adhoc.

  Right now both AP & Ad-Hoc modes use "Group addressed traffic not allowed"
  cipher suite.  This can confuse other implementations.  Instead implement
  a basic GTK support where a randomly or pseudo-randomly generated GTK is
  used and no GTK Rekey is implemented.

  Priority: Medium
  Complexity: C2

- Implement EAP Authenticator certificate element matching

  With TLS based EAP methods it is possible for certain Man-In-The-Middle
  attacks to be performed by having a trusted CA issue a certificate for an
  unrelated domain and then have an adversary utilize that certificate to spoof
  trusted Access Points for a certain SSID.  To prevent this it is possible
  for clients to further limit what certificates they accept by utilizing
  dNSName sub-element of SubjectAltName in the X.509 certificate (or
  alternatively the SubjectName CN) of the Authenticator.  This matching can
  be done by suffix, an exact match, or perhaps even glob matching.

  Priority: Medium
  Complexity: C8