| Message ID | 20190828102042.58016-1-nbd@nbd.name (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | [v2] cfg80211: add local BSS receive time to survey information | expand |
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
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
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
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
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
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
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);
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(+)