* [PATCH v2] cfg80211: add local BSS receive time to survey information
@ 2019-08-28 10:20 Felix Fietkau
2019-08-28 17:25 ` Marcel Holtmann
0 siblings, 1 reply; 7+ messages in thread
From: Felix Fietkau @ 2019-08-28 10:20 UTC (permalink / raw
To: linux-wireless; +Cc: johannes
This is useful for checking how much airtime is being used up by other
transmissions on the channel, e.g. by calculating (time_rx - time_bss_rx)
or (time_busy - time_bss_rx - time_tx)
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
include/net/cfg80211.h | 4 ++++
include/uapi/linux/nl80211.h | 3 +++
net/wireless/nl80211.c | 4 ++++
3 files changed, 11 insertions(+)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 35ec1f0a2bf9..bf97c4f805d3 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -694,6 +694,7 @@ ieee80211_chandef_max_power(struct cfg80211_chan_def *chandef)
* @SURVEY_INFO_TIME_RX: receive time was filled in
* @SURVEY_INFO_TIME_TX: transmit time was filled in
* @SURVEY_INFO_TIME_SCAN: scan time was filled in
+ * @SURVEY_INFO_TIME_BSS_RX: local BSS receive time was filled in
*
* Used by the driver to indicate which info in &struct survey_info
* it has filled in during the get_survey().
@@ -707,6 +708,7 @@ enum survey_info_flags {
SURVEY_INFO_TIME_RX = BIT(5),
SURVEY_INFO_TIME_TX = BIT(6),
SURVEY_INFO_TIME_SCAN = BIT(7),
+ SURVEY_INFO_TIME_BSS_RX = BIT(8),
};
/**
@@ -723,6 +725,7 @@ enum survey_info_flags {
* @time_rx: amount of time the radio spent receiving data
* @time_tx: amount of time the radio spent transmitting data
* @time_scan: amount of time the radio spent for scanning
+ * @time_bss_rx: amount of time the radio spent receiving data on a local BSS
*
* Used by dump_survey() to report back per-channel survey information.
*
@@ -737,6 +740,7 @@ struct survey_info {
u64 time_rx;
u64 time_tx;
u64 time_scan;
+ u64 time_bss_rx;
u32 filled;
s8 noise;
};
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 822851d369ab..e74cf4daad02 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -3843,6 +3843,8 @@ enum nl80211_user_reg_hint_type {
* @NL80211_SURVEY_INFO_TIME_SCAN: time the radio spent for scan
* (on this channel or globally)
* @NL80211_SURVEY_INFO_PAD: attribute used for padding for 64-bit alignment
+ * @NL80211_SURVEY_INFO_TIME_BSS_RX: amount of time the radio spent
+ * receiving local BSS data
* @NL80211_SURVEY_INFO_MAX: highest survey info attribute number
* currently defined
* @__NL80211_SURVEY_INFO_AFTER_LAST: internal use
@@ -3859,6 +3861,7 @@ enum nl80211_survey_info {
NL80211_SURVEY_INFO_TIME_TX,
NL80211_SURVEY_INFO_TIME_SCAN,
NL80211_SURVEY_INFO_PAD,
+ NL80211_SURVEY_INFO_TIME_BSS_RX,
/* keep last */
__NL80211_SURVEY_INFO_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 1a107f29016b..3eea7a6f9070 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -8777,6 +8777,10 @@ static int nl80211_send_survey(struct sk_buff *msg, u32 portid, u32 seq,
nla_put_u64_64bit(msg, NL80211_SURVEY_INFO_TIME_SCAN,
survey->time_scan, NL80211_SURVEY_INFO_PAD))
goto nla_put_failure;
+ if ((survey->filled & SURVEY_INFO_TIME_BSS_RX) &&
+ nla_put_u64_64bit(msg, NL80211_SURVEY_INFO_TIME_BSS_RX,
+ survey->time_bss_rx, NL80211_SURVEY_INFO_PAD))
+ goto nla_put_failure;
nla_nest_end(msg, infoattr);
--
2.17.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2] cfg80211: add local BSS receive time to survey information
2019-08-28 10:20 [PATCH v2] cfg80211: add local BSS receive time to survey information Felix Fietkau
@ 2019-08-28 17:25 ` Marcel Holtmann
2019-08-28 19:44 ` Johannes Berg
0 siblings, 1 reply; 7+ messages in thread
From: Marcel Holtmann @ 2019-08-28 17:25 UTC (permalink / raw
To: Felix Fietkau; +Cc: linux-wireless, Johannes Berg
Hi Felix,
> This is useful for checking how much airtime is being used up by other
> transmissions on the channel, e.g. by calculating (time_rx - time_bss_rx)
> or (time_busy - time_bss_rx - time_tx)
>
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---
> include/net/cfg80211.h | 4 ++++
> include/uapi/linux/nl80211.h | 3 +++
> net/wireless/nl80211.c | 4 ++++
> 3 files changed, 11 insertions(+)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 35ec1f0a2bf9..bf97c4f805d3 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -694,6 +694,7 @@ ieee80211_chandef_max_power(struct cfg80211_chan_def *chandef)
> * @SURVEY_INFO_TIME_RX: receive time was filled in
> * @SURVEY_INFO_TIME_TX: transmit time was filled in
> * @SURVEY_INFO_TIME_SCAN: scan time was filled in
> + * @SURVEY_INFO_TIME_BSS_RX: local BSS receive time was filled in
> *
> * Used by the driver to indicate which info in &struct survey_info
> * it has filled in during the get_survey().
> @@ -707,6 +708,7 @@ enum survey_info_flags {
> SURVEY_INFO_TIME_RX = BIT(5),
> SURVEY_INFO_TIME_TX = BIT(6),
> SURVEY_INFO_TIME_SCAN = BIT(7),
> + SURVEY_INFO_TIME_BSS_RX = BIT(8),
> };
>
> /**
> @@ -723,6 +725,7 @@ enum survey_info_flags {
> * @time_rx: amount of time the radio spent receiving data
> * @time_tx: amount of time the radio spent transmitting data
> * @time_scan: amount of time the radio spent for scanning
> + * @time_bss_rx: amount of time the radio spent receiving data on a local BSS
> *
> * Used by dump_survey() to report back per-channel survey information.
> *
> @@ -737,6 +740,7 @@ struct survey_info {
> u64 time_rx;
> u64 time_tx;
> u64 time_scan;
> + u64 time_bss_rx;
> u32 filled;
> s8 noise;
> };
> diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> index 822851d369ab..e74cf4daad02 100644
> --- a/include/uapi/linux/nl80211.h
> +++ b/include/uapi/linux/nl80211.h
> @@ -3843,6 +3843,8 @@ enum nl80211_user_reg_hint_type {
> * @NL80211_SURVEY_INFO_TIME_SCAN: time the radio spent for scan
> * (on this channel or globally)
> * @NL80211_SURVEY_INFO_PAD: attribute used for padding for 64-bit alignment
> + * @NL80211_SURVEY_INFO_TIME_BSS_RX: amount of time the radio spent
> + * receiving local BSS data
> * @NL80211_SURVEY_INFO_MAX: highest survey info attribute number
> * currently defined
> * @__NL80211_SURVEY_INFO_AFTER_LAST: internal use
> @@ -3859,6 +3861,7 @@ enum nl80211_survey_info {
> NL80211_SURVEY_INFO_TIME_TX,
> NL80211_SURVEY_INFO_TIME_SCAN,
> NL80211_SURVEY_INFO_PAD,
> + NL80211_SURVEY_INFO_TIME_BSS_RX,
wouldn’t this go before the PAD attribute?
Regards
Marcel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] cfg80211: add local BSS receive time to survey information
2019-08-28 17:25 ` Marcel Holtmann
@ 2019-08-28 19:44 ` Johannes Berg
2019-08-28 19:52 ` Marcel Holtmann
0 siblings, 1 reply; 7+ messages in thread
From: Johannes Berg @ 2019-08-28 19:44 UTC (permalink / raw
To: Marcel Holtmann, Felix Fietkau; +Cc: linux-wireless
Hi Marcel,
> ... [snip]
Please trim quotes a bit.
> > NL80211_SURVEY_INFO_PAD,
> > + NL80211_SURVEY_INFO_TIME_BSS_RX,
>
> wouldn’t this go before the PAD attribute?
No, as usual, that would break ABI. PAD is a regular attribute, just
empty and ignored for aligning 64-bit values.
johannes
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] cfg80211: add local BSS receive time to survey information
2019-08-28 19:44 ` Johannes Berg
@ 2019-08-28 19:52 ` Marcel Holtmann
2019-08-28 19:59 ` Johannes Berg
0 siblings, 1 reply; 7+ messages in thread
From: Marcel Holtmann @ 2019-08-28 19:52 UTC (permalink / raw
To: Johannes Berg; +Cc: Felix Fietkau, linux-wireless
Hi Johannes,
>> ... [snip]
>
> Please trim quotes a bit.
>
>>> NL80211_SURVEY_INFO_PAD,
>>> + NL80211_SURVEY_INFO_TIME_BSS_RX,
>>
>> wouldn’t this go before the PAD attribute?
>
> No, as usual, that would break ABI. PAD is a regular attribute, just
> empty and ignored for aligning 64-bit values.
then I do not grok on how the nla_put_u64_64bit works, but that is fine.
I assumed these are similar to the NL80211_SURVEY_INFO_MAX which we also always move, but also not expected to be part of the API as a fixed value.
Regards
Marcel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] cfg80211: add local BSS receive time to survey information
2019-08-28 19:52 ` Marcel Holtmann
@ 2019-08-28 19:59 ` Johannes Berg
2019-08-28 20:24 ` Marcel Holtmann
0 siblings, 1 reply; 7+ messages in thread
From: Johannes Berg @ 2019-08-28 19:59 UTC (permalink / raw
To: Marcel Holtmann; +Cc: Felix Fietkau, linux-wireless
Hi Marcel,
> > No, as usual, that would break ABI. PAD is a regular attribute, just
> > empty and ignored for aligning 64-bit values.
>
> then I do not grok on how the nla_put_u64_64bit works, but that is
> fine.
>
> I assumed these are similar to the NL80211_SURVEY_INFO_MAX which we
> also always move, but also not expected to be part of the API as a
> fixed value.
No no, the _MAX is just the token we use for knowing what we want as the
maximum when parsing etc.
The _PAD is actually a real attribute, basically nla_put_u64_64bit()
will do "nla_put_flag(_PAD)" if and only if "offset % 8 == 0", in order
to actually 64-bit align the 64-bit value in the following attribute.
(Note that offset % 8 can only be 0 or 4, due to the way netlink
attributes work.)
johannes
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] cfg80211: add local BSS receive time to survey information
2019-08-28 19:59 ` Johannes Berg
@ 2019-08-28 20:24 ` Marcel Holtmann
2019-08-28 20:28 ` Johannes Berg
0 siblings, 1 reply; 7+ messages in thread
From: Marcel Holtmann @ 2019-08-28 20:24 UTC (permalink / raw
To: Johannes Berg; +Cc: Felix Fietkau, linux-wireless
Hi Johannes,
>>> No, as usual, that would break ABI. PAD is a regular attribute, just
>>> empty and ignored for aligning 64-bit values.
>>
>> then I do not grok on how the nla_put_u64_64bit works, but that is
>> fine.
>>
>> I assumed these are similar to the NL80211_SURVEY_INFO_MAX which we
>> also always move, but also not expected to be part of the API as a
>> fixed value.
>
> No no, the _MAX is just the token we use for knowing what we want as the
> maximum when parsing etc.
>
> The _PAD is actually a real attribute, basically nla_put_u64_64bit()
> will do "nla_put_flag(_PAD)" if and only if "offset % 8 == 0", in order
> to actually 64-bit align the 64-bit value in the following attribute.
>
> (Note that offset % 8 can only be 0 or 4, due to the way netlink
> attributes work.)
I get that part now. So the kernel is inserting a _PAD, but userspace is still not doing that. So for NL80211_ATTR_WDEV we should be doing the same actually?
Regards
Marcel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] cfg80211: add local BSS receive time to survey information
2019-08-28 20:24 ` Marcel Holtmann
@ 2019-08-28 20:28 ` Johannes Berg
0 siblings, 0 replies; 7+ messages in thread
From: Johannes Berg @ 2019-08-28 20:28 UTC (permalink / raw
To: Marcel Holtmann; +Cc: Felix Fietkau, linux-wireless
On Wed, 2019-08-28 at 22:24 +0200, Marcel Holtmann wrote:
> Hi Johannes,
>
> > > > No, as usual, that would break ABI. PAD is a regular attribute, just
> > > > empty and ignored for aligning 64-bit values.
> > >
> > > then I do not grok on how the nla_put_u64_64bit works, but that is
> > > fine.
> > >
> > > I assumed these are similar to the NL80211_SURVEY_INFO_MAX which we
> > > also always move, but also not expected to be part of the API as a
> > > fixed value.
> >
> > No no, the _MAX is just the token we use for knowing what we want as the
> > maximum when parsing etc.
> >
> > The _PAD is actually a real attribute, basically nla_put_u64_64bit()
> > will do "nla_put_flag(_PAD)" if and only if "offset % 8 == 0", in order
> > to actually 64-bit align the 64-bit value in the following attribute.
> >
> > (Note that offset % 8 can only be 0 or 4, due to the way netlink
> > attributes work.)
>
> I get that part now. So the kernel is inserting a _PAD, but userspace
> is still not doing that.
Yeah, and I forgot to say - if we renumbered _PAD, then newer userspace
would think old kernel's _PAD is really _BSS_RX, so things would break.
> So for NL80211_ATTR_WDEV we should be doing the same actually?
Not really. The kernel doesn't rely on it, nla_get_u64() uses
nla_memcpy() so doesn't care about alignment.
Even userspace doesn't (usually) rely on the alignment, it also
typically uses nla_get_u64() from libnl which also uses nla_memcpy() or
memcpy() (depending on the version), so it's all not really necessary.
I think some libraries or tools like maybe iproute2 didn't do it
correctly and just dereferenced a pointer there, causing alignment
violations, and so basically the decision was to get rid of unaligned
64-bit attributes to prevent that once and for all.
johannes
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-08-28 20:28 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2019-08-28 10:20 [PATCH v2] cfg80211: add local BSS receive time to survey information Felix Fietkau
2019-08-28 17:25 ` Marcel Holtmann
2019-08-28 19:44 ` Johannes Berg
2019-08-28 19:52 ` Marcel Holtmann
2019-08-28 19:59 ` Johannes Berg
2019-08-28 20:24 ` Marcel Holtmann
2019-08-28 20:28 ` Johannes Berg
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