Date: Tue, 12 Nov 2013 13:47:42 +0900 (JST) From: Hiroki Sato <hrs@FreeBSD.org> To: jhb@FreeBSD.org Cc: clutton@zoho.com, freebsd-wireless@FreeBSD.org, freebsd-arch@FreeBSD.org Subject: Re: service netif restart [iface] runs a wpa_supplicant twice Message-ID: <20131112.134742.1669584178551946391.hrs@allbsd.org> In-Reply-To: <201311051154.18872.jhb@freebsd.org> References: <1383419596.3253.42.camel@eva02.mbsd> <CAJ-VmomAiBTFiiFn6ENtJMjBurhq-U2nFh_vWeOxkN=3d6MZTQ@mail.gmail.com> <201311051154.18872.jhb@freebsd.org>
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John Baldwin <jhb@freebsd.org> wrote
in <201311051154.18872.jhb@freebsd.org>:
jh> I also tested vlans created via vlans_<if> and they should use the same fix as
jh> well. Note that this model is more consistent with how cloned_interfaces
jh> works where ifn_start is not explicitly run when each interface is created.
jh> Instead, we rely on devd kicking off pccard_ether for those as well.
No, for cloned_interfaces, the ifn_start will be kicked even when
devd is unavailable because rc.d/netif calls clone_up() and then
ifn_start() sequentially. Since an IFNET ATTACH event is generated
upon clone_up(), so actually the ifn_start() runs twice on every boot
time (or rc.d/netif restart ifn).
Since childif_*() is invoked at the end of ifn_*(), configuration of
the child interfaces does not happen. This is the reason why there
was ifn_start() in childif_create().
It is not efficient and it is reasonable to leave ifn_start() to devd
if available, but it is difficult to detect it correctly because the
IFNET ATTACH handler may be disabled in devd.conf. "pgrep devd" is
not reliable enough.
As pointed out, this duplication can be a problem when configuration
is performed by a program because multiple instances of the program
are invoked. In the other cases, there is no problem because
ifn_start() is idempotent, though.
As a workaround, dhclient is not invoked from ifconfig_up() like
this:
222 if wpaif $1; then
223 /etc/rc.d/wpa_supplicant start $1
224 _cfg=0 # XXX: not sure this should count
225 elif hostapif $1; then
226 /etc/rc.d/hostapd start $1
227 _cfg=0
228 fi
229
230 if dhcpif $1; then
231 if [ $_cfg -ne 0 ] ; then
232 ${IFCONFIG_CMD} $1 up
233 fi
234 if syncdhcpif $1; then
235 /etc/rc.d/dhclient start $1
236 fi
237 _cfg=0
238 fi
ifconfig_IF="DHCP" means to leave invoking dhclient to devd, and
ifconfig_IF="SYNCDHCP" means rc.d/netif calls dhclient directly. I
think similar workaround can be implemented for WPA and HOSTAP and
solve the originally-reported problem.
For inconsistency childif_*(), what do you think about integrating
vlans_IF and wlans_IF into cloned_interfaces and removing the
childif_*() stage in ifn_*()? We can keep vlans_IF and wlans_IF as
well as introduce a new syntax into cloned_interfaces like
cloned_interfaces="em0.100 em0.110 em0.myvlan ath0.wlan0"
which is equivalent to
vlans_em0="100 110 myvlan"
wlans_ath0="wlan0"
The rc.d/netif does clone_up() for the child interfaces first and
then does ifn_start() for them, so
# service netif restart wlan0
works as expected (tear down, recreate, and reconfigure the
interface).
Of course, this does not solve the duplicate invocation of the netif
script. To solve it, I think we need a knob to disable IFNET events
in a per-interface basis temporarily.
-- Hiroki
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