In the drv_mac80211_setup function, mac80211_interface_cleanup
is called to ask the kernel to delete all existing interfaces
for the phy that is being configured via netlink.
Later in the first function, mac80211_prepare_vif is called to
set up the new interfaces as required.
But sometimes, when mac80211_prepare_vif (and so the relevant
`iw phy x interface add y` command) runs, the kernel might still
be cleaning up the old interface with the same ifname. It usually
takes very few time to do that; possibly a few milliseconds of
sleep in the script after detecting this error condition could be
enough, but the busybox sh does not support sub-second sleep
intervals.
When this happens, iw obviously fails to create the new interface;
and the following message is printed in the system log, followed by
subsequent failure messages from hostapd in case this would have been
an AP interface.
Tue Mar 14 04:21:57 2017 daemon.notice netifd: radio1 (2767): command failed:
Too many open files in system (-23)
This was a long-standing issue existing since at least OpenWrt Backfire,
and today I finally managed to debug and (hopefully) solve it.
It was happening very few times on most devices; but it was happening
a lot more frequently on fast platforms with multiple radios, such as
the powerpc-based dual-ath9k-radio tl-wdr4900-v1.
Signed-off-by: Vittorio Gambaletta <open...@vittgam.net>
---
.../mac80211/files/lib/netifd/wireless/mac80211.sh | 35 +++++++++++++++++---
1 file changed, 30 insertions(+), 5 deletions(-)
diff --git a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
index baa023e..5058b01 100644
--- a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
+++ b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
@@ -411,6 +411,31 @@ mac80211_check_ap() {
has_ap=1
}
+mac80211_iw_interface_add() {
+ local phy="$1"
+ local ifname="$2"
+ local type="$3"
+ local wdsflag="$4"
+
+ iw phy "$phy" interface add "$ifname" type "$type" $wdsflag
+ ret="$?"
+
+ [ "$ret" = 233 ] && {
+ # Device might have just been deleted, give the kernel some
time to finish cleaning it up
+ sleep 1
+
+ iw phy "$phy" interface add "$ifname" type "$type" $wdsflag
+ ret="$?"
+ }
+
+ [ "$ret" != 0 ] && {
+ wireless_setup_failed INTERFACE_CREATION_FAILED
+ return 1
+ }
+
+ return 0
+}
+
mac80211_prepare_vif() {
json_select config
@@ -437,7 +462,7 @@ mac80211_prepare_vif() {
# It is far easier to delete and create the desired interface
case "$mode" in
adhoc)
- iw phy "$phy" interface add "$ifname" type adhoc
+ mac80211_iw_interface_add "$phy" "$ifname" adhoc ||
return
;;
ap)
# Hostapd will handle recreating the interface and
@@ -451,21 +476,21 @@ mac80211_prepare_vif() {
mac80211_hostapd_setup_bss "$phy" "$ifname" "$macaddr"
"$type" || return
[ -n "$hostapd_ctrl" ] || {
- iw phy "$phy" interface add "$ifname" type __ap
+ mac80211_iw_interface_add "$phy" "$ifname" __ap
|| return
hostapd_ctrl="${hostapd_ctrl:-/var/run/hostapd/$ifname}"
}
;;
mesh)
- iw phy "$phy" interface add "$ifname" type mp
+ mac80211_iw_interface_add "$phy" "$ifname" mp || return
;;
monitor)
- iw phy "$phy" interface add "$ifname" type monitor
+ mac80211_iw_interface_add "$phy" "$ifname" monitor ||
return
;;
sta)
local wdsflag=
staidx="$(($staidx + 1))"
[ "$wds" -gt 0 ] && wdsflag="4addr on"
- iw phy "$phy" interface add "$ifname" type managed
$wdsflag
+ mac80211_iw_interface_add "$phy" "$ifname" managed
"$wdsflag" || return
[ "$powersave" -gt 0 ] && powersave="on" ||
powersave="off"
iw "$ifname" set power_save "$powersave"
;;
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