nl80211: add generation number to all dumps
In order for userspace to be able to figure out whether
it obtained a consistent snapshot of data or not when
using netlink dumps, we need to have a generation number
in each dump message that indicates whether the list has
changed or not -- its value is arbitrary.
This patch adds such a number to all dumps, this needs
some mac80211 involvement to keep track of a generation
number to start with when adding/removing mesh paths or
stations.
The wiphy and netdev lists can be fully handled within
cfg80211, of course, but generation numbers need to be
stored there as well.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 1e18930..62e1ac0 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -32,6 +32,7 @@
* only read the list, and that can happen quite
* often because we need to do it for each command */
LIST_HEAD(cfg80211_rdev_list);
+int cfg80211_rdev_list_generation;
/*
* This is used to protect the cfg80211_rdev_list
@@ -511,6 +512,7 @@
wiphy_update_regulatory(wiphy, NL80211_REGDOM_SET_BY_CORE);
list_add(&rdev->list, &cfg80211_rdev_list);
+ cfg80211_rdev_list_generation++;
mutex_unlock(&cfg80211_mutex);
@@ -593,6 +595,7 @@
reg_device_remove(wiphy);
list_del(&rdev->list);
+ cfg80211_rdev_list_generation++;
device_del(&rdev->wiphy.dev);
debugfs_remove(rdev->wiphy.debugfsdir);
@@ -653,6 +656,7 @@
spin_lock_init(&wdev->event_lock);
mutex_lock(&rdev->devlist_mtx);
list_add(&wdev->list, &rdev->netdev_list);
+ rdev->devlist_generation++;
/* can only change netns with wiphy */
dev->features |= NETIF_F_NETNS_LOCAL;
@@ -733,6 +737,7 @@
if (!list_empty(&wdev->list)) {
sysfs_remove_link(&dev->dev.kobj, "phy80211");
list_del_init(&wdev->list);
+ rdev->devlist_generation++;
mutex_destroy(&wdev->mtx);
#ifdef CONFIG_WIRELESS_EXT
kfree(wdev->wext.keys);
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 92e0492..639db52 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -49,6 +49,7 @@
/* associate netdev list */
struct mutex devlist_mtx;
struct list_head netdev_list;
+ int devlist_generation;
/* BSSes/scanning */
spinlock_t bss_lock;
@@ -101,6 +102,7 @@
extern struct mutex cfg80211_mutex;
extern struct list_head cfg80211_rdev_list;
+extern int cfg80211_rdev_list_generation;
#define assert_cfg80211_lock() WARN_ON(!mutex_is_locked(&cfg80211_mutex))
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 2ff7376..b3d5c1d 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -408,6 +408,9 @@
NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, dev->wiphy_idx);
NLA_PUT_STRING(msg, NL80211_ATTR_WIPHY_NAME, wiphy_name(&dev->wiphy));
+ NLA_PUT_U32(msg, NL80211_ATTR_GENERATION,
+ cfg80211_rdev_list_generation);
+
NLA_PUT_U8(msg, NL80211_ATTR_WIPHY_RETRY_SHORT,
dev->wiphy.retry_short);
NLA_PUT_U8(msg, NL80211_ATTR_WIPHY_RETRY_LONG,
@@ -825,6 +828,11 @@
NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, dev->name);
NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, dev->ieee80211_ptr->iftype);
+
+ NLA_PUT_U32(msg, NL80211_ATTR_GENERATION,
+ rdev->devlist_generation ^
+ (cfg80211_rdev_list_generation << 2));
+
return genlmsg_end(msg, hdr);
nla_put_failure:
@@ -838,12 +846,12 @@
int if_idx = 0;
int wp_start = cb->args[0];
int if_start = cb->args[1];
- struct cfg80211_registered_device *dev;
+ struct cfg80211_registered_device *rdev;
struct wireless_dev *wdev;
mutex_lock(&cfg80211_mutex);
- list_for_each_entry(dev, &cfg80211_rdev_list, list) {
- if (!net_eq(wiphy_net(&dev->wiphy), sock_net(skb->sk)))
+ list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+ if (!net_eq(wiphy_net(&rdev->wiphy), sock_net(skb->sk)))
continue;
if (wp_idx < wp_start) {
wp_idx++;
@@ -851,21 +859,21 @@
}
if_idx = 0;
- mutex_lock(&dev->devlist_mtx);
- list_for_each_entry(wdev, &dev->netdev_list, list) {
+ mutex_lock(&rdev->devlist_mtx);
+ list_for_each_entry(wdev, &rdev->netdev_list, list) {
if (if_idx < if_start) {
if_idx++;
continue;
}
if (nl80211_send_iface(skb, NETLINK_CB(cb->skb).pid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
- dev, wdev->netdev) < 0) {
- mutex_unlock(&dev->devlist_mtx);
+ rdev, wdev->netdev) < 0) {
+ mutex_unlock(&rdev->devlist_mtx);
goto out;
}
if_idx++;
}
- mutex_unlock(&dev->devlist_mtx);
+ mutex_unlock(&rdev->devlist_mtx);
wp_idx++;
}
@@ -1616,6 +1624,8 @@
NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, dev->ifindex);
NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr);
+ NLA_PUT_U32(msg, NL80211_ATTR_GENERATION, sinfo->generation);
+
sinfoattr = nla_nest_start(msg, NL80211_ATTR_STA_INFO);
if (!sinfoattr)
goto nla_put_failure;
@@ -2101,6 +2111,8 @@
NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, dst);
NLA_PUT(msg, NL80211_ATTR_MPATH_NEXT_HOP, ETH_ALEN, next_hop);
+ NLA_PUT_U32(msg, NL80211_ATTR_GENERATION, pinfo->generation);
+
pinfoattr = nla_nest_start(msg, NL80211_ATTR_MPATH_INFO);
if (!pinfoattr)
goto nla_put_failure;
@@ -3090,8 +3102,7 @@
if (!hdr)
return -1;
- NLA_PUT_U32(msg, NL80211_ATTR_SCAN_GENERATION,
- rdev->bss_generation);
+ NLA_PUT_U32(msg, NL80211_ATTR_GENERATION, rdev->bss_generation);
NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, wdev->netdev->ifindex);
bss = nla_nest_start(msg, NL80211_ATTR_BSS);
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 0ccf3a0..1bcb131 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -562,6 +562,7 @@
spin_lock_bh(&dev->bss_lock);
list_del(&bss->list);
+ dev->bss_generation++;
rb_erase(&bss->rbn, &dev->bss_tree);
spin_unlock_bh(&dev->bss_lock);