2020-09-28 11:09:22

by Johannes Berg

[permalink] [raw]
Subject: [PATCH] nl80211: reduce non-split wiphy dump size

From: Johannes Berg <[email protected]>

When wiphy dumps cannot be split, such as in events or with
older userspace that doesn't support it, the size can today
be too big.

Reduce it, by doing two things:

1) remove data that couldn't have been present before the
split capability was introduced since it's new, such as
HE capabilities

2) as suggested by Martin Willi, remove management frame
subtypes from the split dumps, as just (1) isn't even
enough due to other new code capabilities. This is fine
as old consumers (really just wpa_supplicant) didn't
check this data before they got support for split dumps.

Reported-by: Martin Willi <[email protected]>
Suggested-by: Martin Willi <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>
---
net/wireless/nl80211.c | 37 ++++++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 935ff973412a..9633b7af04c4 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -926,6 +926,8 @@ static int nl80211_msg_put_channel(struct sk_buff *msg, struct wiphy *wiphy,
if (!large && chan->flags &
(IEEE80211_CHAN_NO_10MHZ | IEEE80211_CHAN_NO_20MHZ))
return 0;
+ if (!large && chan->freq_offset)
+ return 0;

if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_FREQ,
chan->center_freq))
@@ -1603,7 +1605,8 @@ nl80211_send_iftype_data(struct sk_buff *msg,
}

static int nl80211_send_band_rateinfo(struct sk_buff *msg,
- struct ieee80211_supported_band *sband)
+ struct ieee80211_supported_band *sband,
+ bool large)
{
struct nlattr *nl_rates, *nl_rate;
struct ieee80211_rate *rate;
@@ -1631,7 +1634,7 @@ static int nl80211_send_band_rateinfo(struct sk_buff *msg,
sband->vht_cap.cap)))
return -ENOBUFS;

- if (sband->n_iftype_data) {
+ if (large && sband->n_iftype_data) {
struct nlattr *nl_iftype_data =
nla_nest_start_noflag(msg,
NL80211_BAND_ATTR_IFTYPE_DATA);
@@ -1659,7 +1662,7 @@ static int nl80211_send_band_rateinfo(struct sk_buff *msg,
}

/* add EDMG info */
- if (sband->edmg_cap.channels &&
+ if (large && sband->edmg_cap.channels &&
(nla_put_u8(msg, NL80211_BAND_ATTR_EDMG_CHANNELS,
sband->edmg_cap.channels) ||
nla_put_u8(msg, NL80211_BAND_ATTR_EDMG_BW_CONFIG,
@@ -2077,13 +2080,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
nla_put_u16(msg, NL80211_ATTR_MAX_SCHED_SCAN_IE_LEN,
rdev->wiphy.max_sched_scan_ie_len) ||
nla_put_u8(msg, NL80211_ATTR_MAX_MATCH_SETS,
- rdev->wiphy.max_match_sets) ||
- nla_put_u32(msg, NL80211_ATTR_MAX_NUM_SCHED_SCAN_PLANS,
- rdev->wiphy.max_sched_scan_plans) ||
- nla_put_u32(msg, NL80211_ATTR_MAX_SCAN_PLAN_INTERVAL,
- rdev->wiphy.max_sched_scan_plan_interval) ||
- nla_put_u32(msg, NL80211_ATTR_MAX_SCAN_PLAN_ITERATIONS,
- rdev->wiphy.max_sched_scan_plan_iterations))
+ rdev->wiphy.max_match_sets))
goto nla_put_failure;

if ((rdev->wiphy.flags & WIPHY_FLAG_IBSS_RSN) &&
@@ -2173,6 +2170,10 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
band < NUM_NL80211_BANDS; band++) {
struct ieee80211_supported_band *sband;

+ /* omit higher bands for ancient software */
+ if (band > NL80211_BAND_5GHZ && !state->split)
+ break;
+
sband = rdev->wiphy.bands[band];

if (!sband)
@@ -2184,7 +2185,8 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,

switch (state->chan_start) {
case 0:
- if (nl80211_send_band_rateinfo(msg, sband))
+ if (nl80211_send_band_rateinfo(msg, sband,
+ state->split))
goto nla_put_failure;
state->chan_start++;
if (state->split)
@@ -2286,8 +2288,6 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
nla_put_flag(msg, NL80211_ATTR_OFFCHANNEL_TX_OK))
goto nla_put_failure;

- if (nl80211_send_mgmt_stypes(msg, mgmt_stypes))
- goto nla_put_failure;
state->split_start++;
if (state->split)
break;
@@ -2361,6 +2361,17 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
state->split_start = 0;
break;
case 9:
+ if (nl80211_send_mgmt_stypes(msg, mgmt_stypes))
+ goto nla_put_failure;
+
+ if (nla_put_u32(msg, NL80211_ATTR_MAX_NUM_SCHED_SCAN_PLANS,
+ rdev->wiphy.max_sched_scan_plans) ||
+ nla_put_u32(msg, NL80211_ATTR_MAX_SCAN_PLAN_INTERVAL,
+ rdev->wiphy.max_sched_scan_plan_interval) ||
+ nla_put_u32(msg, NL80211_ATTR_MAX_SCAN_PLAN_ITERATIONS,
+ rdev->wiphy.max_sched_scan_plan_iterations))
+ goto nla_put_failure;
+
if (rdev->wiphy.extended_capabilities &&
(nla_put(msg, NL80211_ATTR_EXT_CAPA,
rdev->wiphy.extended_capabilities_len,
--
2.26.2


2020-09-29 08:46:42

by Martin Willi

[permalink] [raw]
Subject: Re: [PATCH] nl80211: reduce non-split wiphy dump size

Johannes,

> When wiphy dumps cannot be split, such as in events or with
> older userspace that doesn't support it, the size can today
> be too big.
>
> Reduce it, by doing two things:

Thanks for the improved patch, works for me:

Tested-by: Martin Willi <[email protected]>