pkg/55494: wpa_supplicant missing linux wifi driver

[nykula%ukr.net@localhost]

>Number:         55494
>Category:       pkg
>Synopsis:       wpa_supplicant missing linux wifi driver
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jul 16 20:15:00 +0000 2020
>Originator:     Denys Nykula
>Release:        current
>Organization:
>Environment:
Linux e11 5.4.48_1 #1 SMP PREEMPT Mon Jun 22 10:55:16 UTC 2020 x86_64 GNU/Linux
>Description:
Pkgsrc wpa_supplicant defconfig enables no wireless device driver when
building on Linux. So the resulting system can't connect to any Wi-Fi,
as only the wired driver is present.

Linux kernel provides two wifi APIs, ioctl+wext and netlink+cfg80211:
wireless.wiki.kernel.org/en/developers/documentation/wireless-extensions
wireless.wiki.kernel.org/en/developers/documentation/nl80211

Cfg80211 is used by new drivers being added to the kernel. It requires
linking wpa_supplicant with an external GPL library, libnl:
http://www.infradead.org/~tgr/libnl/

Wext is frozen but still widely supported. For example, it handles my
ath9k card from 2015. No lib dependency, so one config line enables it.
>How-To-Repeat:
On rolling release of Void Linux:

export SH=/bin/bash
git clone https://github.com/oasislinux/pkgsrc /usr/pkgsrc
cd /usr/pkgsrc/bootstrap; $SH bootstrap --full --prefer-pkgsrc=yes
cd /usr/pkgsrc/net/wpa_supplicant; /usr/pkg/bin/bmake install
/usr/pkg/sbin/wpa_supplicant

(Note that I use Michael Forney's frequently updated pkgsrc fork with
musl libc compat patches.)

The shown help text should have at least one wireless option:

drivers:
  nl80211 = Linux nl80211/cfg80211
  wext = Linux wireless extensions (generic)
  wired = Wired Ethernet driver

But now it just says wired:

drivers:
  wired = Wired Ethernet driver
>Fix:
Add the wext enabling line. If Linux pkgsrc users with new cards ever
appear, revisit this and ask them to package libnl.
--- /dev/null
+++ net/wpa_supplicant/files/defconfig.Linux
@@ -0,0 +1,2 @@
+# for Linux
+CONFIG_DRIVER_WEXT=y