This attribute allows user-space to override or turn of the default
BSS expiration time for NL80211_CMD_GET_SCAN.
It also allows to set an expiration for NL80211_CMD_TRIGGER_SCAN. Setting
the expiration to 0 will clean the whole BSS list.
Signed-off-by: Holger Schurig <hs4233@xxxxxxxxxxxxxxxxxxxx>
---
Currently, I'm using the user-space AS-IS. Maybe I should do
export = nla_get_u32(..) * HZ
or, if we want to specify this in ms:
export = nla_get_u32(..) * HZ / 1000
???
A simple demo patch for iw that swaps behavior (expire all BSS at scan time,
never expire at dump time) is here:
xx iw.orig/scan.c 2009-09-18 16:28:07.000000000 +0200
xx iw/scan.c 2009-09-18 16:45:41.000000000 +0200
xx -102,6 +102,8 @@ static int handle_scan(struct nl80211_st
if (have_freqs)
nla_put_nested(msg, NL80211_ATTR_SCAN_FREQUENCIES, freqs);
+ NLA_PUT_U32(msg, 83 /* NL80211_ATTR_SCAN_EXPIRE */, 0);
+
err = 0;
nla_put_failure:
nlmsg_free(ssids);
xx -871,7 +873,10 @@ static int handle_scan_dump(struct nl802
nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_bss_handler,
&scan_params);
+ NLA_PUT_U32(msg, 83 /* NL80211_ATTR_SCAN_EXPIRE */, 0);
return 0;
+nla_put_failure:
+ return 2;
}
static int handle_scan_combined(struct nl80211_state *state,
Index: linux-wl/net/wireless/core.h
===================================================================
--- linux-wl.orig/net/wireless/core.h 2009-09-18 14:49:42.000000000 +0200
+++ linux-wl/net/wireless/core.h 2009-09-18 17:31:05.000000000 +0200
@@ -270,7 +270,9 @@ void ieee80211_set_bitrate_flags(struct
void wiphy_update_regulatory(struct wiphy *wiphy,
enum nl80211_reg_initiator setby);
-void cfg80211_bss_expire(struct cfg80211_registered_device *dev);
+#define IEEE80211_SCAN_RESULT_EXPIRE (15 * HZ)
+
+void cfg80211_bss_expire(struct cfg80211_registered_device *dev, int expire);
void cfg80211_bss_age(struct cfg80211_registered_device *dev,
unsigned long age_secs);
Index: linux-wl/net/wireless/nl80211.c
===================================================================
--- linux-wl.orig/net/wireless/nl80211.c 2009-09-18 14:49:42.000000000 +0200
+++ linux-wl/net/wireless/nl80211.c 2009-09-18 17:36:04.000000000 +0200
@@ -138,6 +138,7 @@ static struct nla_policy nl80211_policy[
[NL80211_ATTR_CIPHER_SUITE_GROUP] = { .type = NLA_U32 },
[NL80211_ATTR_WPA_VERSIONS] = { .type = NLA_U32 },
[NL80211_ATTR_PID] = { .type = NLA_U32 },
+ [NL80211_ATTR_SCAN_EXPIRE] = { .type = NLA_U32 },
};
/* policy for the attributes */
@@ -2945,6 +2946,13 @@ static int nl80211_trigger_scan(struct s
goto out;
}
+ if (info->attrs[NL80211_ATTR_SCAN_EXPIRE]) {
+ u32 expire = nla_get_u32(info->attrs[NL80211_ATTR_SCAN_EXPIRE]);
+ spin_lock_bh(&rdev->bss_lock);
+ cfg80211_bss_expire(rdev, expire);
+ spin_unlock_bh(&rdev->bss_lock);
+ }
+
if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
n_channels = validate_scan_freqs(
info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]);
@@ -3158,11 +3166,13 @@ static int nl80211_dump_scan(struct sk_b
int ifidx = cb->args[0];
int start = cb->args[1], idx = 0;
int err;
+ u32 expire = IEEE80211_SCAN_RESULT_EXPIRE;
+
+ err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
+ nl80211_fam.attrbuf, nl80211_fam.maxattr,
+ nl80211_policy);
if (!ifidx) {
- err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
- nl80211_fam.attrbuf, nl80211_fam.maxattr,
- nl80211_policy);
if (err)
return err;
@@ -3187,9 +3197,20 @@ static int nl80211_dump_scan(struct sk_b
wdev = dev->ieee80211_ptr;
+ /*
+ * If expire is set (the default), expire the BSS list before
+ * returning values. However, user-space can set a different
+ * expire time via NL80211_ATTR_SCAN_EXPIRE. It can also set
+ * no expire-time at all, then we skip the expiration.
+ */
+ if (!err && nl80211_fam.attrbuf[NL80211_ATTR_SCAN_EXPIRE])
+ expire =
+ nla_get_u32(nl80211_fam.attrbuf[NL80211_ATTR_SCAN_EXPIRE]);
+
wdev_lock(wdev);
spin_lock_bh(&rdev->bss_lock);
- cfg80211_bss_expire(rdev);
+ if (expire)
+ cfg80211_bss_expire(rdev, expire);
list_for_each_entry(scan, &rdev->bss_list, list) {
if (++idx <= start)
Index: linux-wl/net/wireless/scan.c
===================================================================
--- linux-wl.orig/net/wireless/scan.c 2009-09-18 14:49:42.000000000 +0200
+++ linux-wl/net/wireless/scan.c 2009-09-18 17:32:08.000000000 +0200
@@ -16,8 +16,6 @@
#include "nl80211.h"
#include "wext-compat.h"
-#define IEEE80211_SCAN_RESULT_EXPIRE (15 * HZ)
-
void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
{
struct cfg80211_scan_request *request;
@@ -121,7 +119,7 @@ void cfg80211_bss_age(struct cfg80211_re
}
/* must hold dev->bss_lock! */
-void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
+void cfg80211_bss_expire(struct cfg80211_registered_device *dev, int expire)
{
struct cfg80211_internal_bss *bss, *tmp;
bool expired = false;
@@ -129,7 +127,11 @@ void cfg80211_bss_expire(struct cfg80211
list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
if (atomic_read(&bss->hold))
continue;
- if (!time_after(jiffies, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE))
+ /*
+ * If expire==0, then expire all BSS from the list,
+ * else only expire those that are older than expire.
+ */
+ if (expire && !time_after(jiffies, bss->ts + expire))
continue;
list_del(&bss->list);
rb_erase(&bss->rbn, &dev->bss_tree);
@@ -970,9 +972,11 @@ static int ieee80211_scan_results(struct
char *current_ev = buf;
char *end_buf = buf + len;
struct cfg80211_internal_bss *bss;
+ u32 expire = IEEE80211_SCAN_RESULT_EXPIRE;
spin_lock_bh(&dev->bss_lock);
- cfg80211_bss_expire(dev);
+ if (expire)
+ cfg80211_bss_expire(dev, expire);
list_for_each_entry(bss, &dev->bss_list, list) {
if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
Index: linux-wl/include/linux/nl80211.h
===================================================================
--- linux-wl.orig/include/linux/nl80211.h 2009-09-18 15:10:53.000000000 +0200
+++ linux-wl/include/linux/nl80211.h 2009-09-18 15:11:44.000000000 +0200
@@ -481,6 +481,7 @@ enum nl80211_commands {
* @NL80211_ATTR_SCAN_SSIDS: nested attribute with SSIDs, leave out for passive
* scanning and include a zero-length SSID (wildcard) for wildcard scan
* @NL80211_ATTR_BSS: scan result BSS
+ * @NL80211_ATTR_SCAN: expire time for cached bss list
*
* @NL80211_ATTR_REG_INITIATOR: indicates who requested the regulatory domain
* currently in effect. This could be any of the %NL80211_REGDOM_SET_BY_*
@@ -714,6 +715,8 @@ enum nl80211_attrs {
NL80211_ATTR_PID,
+ NL80211_ATTR_SCAN_EXPIRE,
+
/* add attributes here, update the policy in nl80211.c */
__NL80211_ATTR_AFTER_LAST,
--
http://www.holgerschurig.de
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