* [PATCH] nl80211: add generation number to all dumps
@ 2009-08-07 14:17 Johannes Berg
0 siblings, 0 replies; only message in thread
From: Johannes Berg @ 2009-08-07 14:17 UTC (permalink / raw)
To: John Linville; +Cc: linux-wireless
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>
---
include/linux/nl80211.h | 17 ++++++++++++-----
include/net/cfg80211.h | 12 ++++++++++++
net/mac80211/cfg.c | 4 ++++
net/mac80211/ieee80211_i.h | 1 +
net/mac80211/mesh.h | 2 ++
net/mac80211/mesh_pathtbl.c | 5 +++++
net/mac80211/sta_info.c | 2 ++
net/wireless/core.c | 5 +++++
net/wireless/core.h | 2 ++
net/wireless/nl80211.c | 31 +++++++++++++++++++++----------
net/wireless/scan.c | 1 +
11 files changed, 67 insertions(+), 15 deletions(-)
--- wireless-testing.orig/include/linux/nl80211.h 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/include/linux/nl80211.h 2009-08-07 16:13:58.000000000 +0200
@@ -480,10 +480,6 @@ enum nl80211_commands {
* @NL80211_ATTR_SCAN_FREQUENCIES: nested attribute with frequencies (in MHz)
* @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_SCAN_GENERATION: the scan generation increases whenever the
- * scan result list changes (BSS expired or added) so that applications
- * can verify that they got a single, consistent snapshot (when all dump
- * messages carried the same generation number)
* @NL80211_ATTR_BSS: scan result BSS
*
* @NL80211_ATTR_REG_INITIATOR: indicates who requested the regulatory domain
@@ -580,6 +576,14 @@ enum nl80211_commands {
*
* @NL80211_ATTR_PID: Process ID of a network namespace.
*
+ * @NL80211_ATTR_GENERATION: Used to indicate consistent snapshots for
+ * dumps. This number increases whenever the object list being
+ * dumped changes, and as such userspace can verify that it has
+ * obtained a complete and consistent snapshot by verifying that
+ * all dump messages contain the same generation number. If it
+ * changed then the list changed and the dump should be repeated
+ * completely from scratch.
+ *
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
*/
@@ -651,7 +655,7 @@ enum nl80211_attrs {
NL80211_ATTR_SCAN_FREQUENCIES,
NL80211_ATTR_SCAN_SSIDS,
- NL80211_ATTR_SCAN_GENERATION,
+ NL80211_ATTR_GENERATION, /* replaces old SCAN_GENERATION */
NL80211_ATTR_BSS,
NL80211_ATTR_REG_INITIATOR,
@@ -716,6 +720,9 @@ enum nl80211_attrs {
NL80211_ATTR_MAX = __NL80211_ATTR_AFTER_LAST - 1
};
+/* source-level API compatibility */
+#define NL80211_ATTR_SCAN_GENERATION NL80211_ATTR_GENERATION
+
/*
* Allow user space programs to use #ifdef on new attributes by defining them
* here
--- wireless-testing.orig/net/wireless/nl80211.c 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/wireless/nl80211.c 2009-08-07 16:13:58.000000000 +0200
@@ -408,6 +408,9 @@ static int nl80211_send_wiphy(struct sk_
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 @@ static int nl80211_send_iface(struct sk_
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 @@ static int nl80211_dump_interface(struct
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 @@ static int nl80211_dump_interface(struct
}
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 @@ static int nl80211_send_station(struct s
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 @@ static int nl80211_send_mpath(struct sk_
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 @@ static int nl80211_send_bss(struct sk_bu
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);
--- wireless-testing.orig/net/wireless/core.c 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/wireless/core.c 2009-08-07 16:13:58.000000000 +0200
@@ -32,6 +32,7 @@ MODULE_DESCRIPTION("wireless configurati
* 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 @@ int wiphy_register(struct wiphy *wiphy)
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 @@ void wiphy_unregister(struct wiphy *wiph
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 @@ static int cfg80211_netdev_notifier_call
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 @@ static int cfg80211_netdev_notifier_call
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);
--- wireless-testing.orig/net/wireless/core.h 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/wireless/core.h 2009-08-07 16:13:58.000000000 +0200
@@ -49,6 +49,7 @@ struct cfg80211_registered_device {
/* 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 @@ bool wiphy_idx_valid(int wiphy_idx)
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))
--- wireless-testing.orig/include/net/cfg80211.h 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/include/net/cfg80211.h 2009-08-07 16:13:58.000000000 +0200
@@ -372,6 +372,10 @@ struct rate_info {
* @txrate: current unicast bitrate to this station
* @rx_packets: packets received from this station
* @tx_packets: packets transmitted to this station
+ * @generation: generation number for nl80211 dumps.
+ * This number should increase every time the list of stations
+ * changes, i.e. when a station is added or removed, so that
+ * userspace can tell whether it got a consistent snapshot.
*/
struct station_info {
u32 filled;
@@ -385,6 +389,8 @@ struct station_info {
struct rate_info txrate;
u32 rx_packets;
u32 tx_packets;
+
+ int generation;
};
/**
@@ -444,6 +450,10 @@ enum mpath_info_flags {
* @flags: mesh path flags
* @discovery_timeout: total mesh path discovery timeout, in msecs
* @discovery_retries: mesh path discovery retries
+ * @generation: generation number for nl80211 dumps.
+ * This number should increase every time the list of mesh paths
+ * changes, i.e. when a station is added or removed, so that
+ * userspace can tell whether it got a consistent snapshot.
*/
struct mpath_info {
u32 filled;
@@ -454,6 +464,8 @@ struct mpath_info {
u32 discovery_timeout;
u8 discovery_retries;
u8 flags;
+
+ int generation;
};
/**
--- wireless-testing.orig/net/mac80211/cfg.c 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/mac80211/cfg.c 2009-08-07 16:13:58.000000000 +0200
@@ -323,6 +323,8 @@ static void sta_set_sinfo(struct sta_inf
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
+ sinfo->generation = sdata->local->sta_generation;
+
sinfo->filled = STATION_INFO_INACTIVE_TIME |
STATION_INFO_RX_BYTES |
STATION_INFO_TX_BYTES |
@@ -909,6 +911,8 @@ static void mpath_set_pinfo(struct mesh_
else
memset(next_hop, 0, ETH_ALEN);
+ pinfo->generation = mesh_paths_generation;
+
pinfo->filled = MPATH_INFO_FRAME_QLEN |
MPATH_INFO_DSN |
MPATH_INFO_METRIC |
--- wireless-testing.orig/net/mac80211/ieee80211_i.h 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/mac80211/ieee80211_i.h 2009-08-07 16:13:58.000000000 +0200
@@ -678,6 +678,7 @@ struct ieee80211_local {
struct list_head sta_list;
struct sta_info *sta_hash[STA_HASH_SIZE];
struct timer_list sta_cleanup;
+ int sta_generation;
struct sk_buff_head pending[IEEE80211_MAX_QUEUES];
struct tasklet_struct tx_pending_tasklet;
--- wireless-testing.orig/net/mac80211/sta_info.c 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/mac80211/sta_info.c 2009-08-07 16:13:58.000000000 +0200
@@ -349,6 +349,7 @@ int sta_info_insert(struct sta_info *sta
goto out_free;
}
list_add(&sta->list, &local->sta_list);
+ local->sta_generation++;
local->num_sta++;
sta_info_hash_add(local, sta);
@@ -485,6 +486,7 @@ static void __sta_info_unlink(struct sta
}
local->num_sta--;
+ local->sta_generation++;
if (local->ops->sta_notify) {
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
--- wireless-testing.orig/net/mac80211/mesh.h 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/mac80211/mesh.h 2009-08-07 16:13:58.000000000 +0200
@@ -265,6 +265,8 @@ void mesh_path_discard_frame(struct sk_b
void mesh_path_quiesce(struct ieee80211_sub_if_data *sdata);
void mesh_path_restart(struct ieee80211_sub_if_data *sdata);
+extern int mesh_paths_generation;
+
#ifdef CONFIG_MAC80211_MESH
extern int mesh_allocated;
--- wireless-testing.orig/net/mac80211/mesh_pathtbl.c 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/mac80211/mesh_pathtbl.c 2009-08-07 16:14:16.000000000 +0200
@@ -38,6 +38,8 @@ struct mpath_node {
static struct mesh_table *mesh_paths;
static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
+int mesh_paths_generation;
+
/* This lock will have the grow table function as writer and add / delete nodes
* as readers. When reading the table (i.e. doing lookups) we are well protected
* by RCU
@@ -243,6 +245,8 @@ int mesh_path_add(u8 *dst, struct ieee80
mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
grow = 1;
+ mesh_paths_generation++;
+
spin_unlock(&mesh_paths->hashwlock[hash_idx]);
read_unlock(&pathtbl_resize_lock);
if (grow) {
@@ -484,6 +488,7 @@ int mesh_path_del(u8 *addr, struct ieee8
err = -ENXIO;
enddel:
+ mesh_paths_generation++;
spin_unlock(&mesh_paths->hashwlock[hash_idx]);
read_unlock(&pathtbl_resize_lock);
return err;
--- wireless-testing.orig/net/wireless/scan.c 2009-08-07 16:13:57.000000000 +0200
+++ wireless-testing/net/wireless/scan.c 2009-08-07 16:13:58.000000000 +0200
@@ -562,6 +562,7 @@ void cfg80211_unlink_bss(struct wiphy *w
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);
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