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nl80211: add generation number to all dumps

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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>
This commit is contained in:
Johannes Berg 2009-08-07 16:17:38 +02:00 committed by John W. Linville
parent f401a6f7ed
commit f5ea9120be
11 changed files with 67 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
include/linux/nl80211.h
View file

@ -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

12
include/net/cfg80211.h
View file

@ -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;
};
/**

4
net/mac80211/cfg.c
View file

@ -323,6 +323,8 @@ static void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
{
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_path *mpath, u8 *next_hop,
else
memset(next_hop, 0, ETH_ALEN);
pinfo->generation = mesh_paths_generation;
pinfo->filled = MPATH_INFO_FRAME_QLEN |
MPATH_INFO_DSN |
MPATH_INFO_METRIC |

1
net/mac80211/ieee80211_i.h
View file

@ -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;

2
net/mac80211/mesh.h
View file

@ -265,6 +265,8 @@ void mesh_path_discard_frame(struct sk_buff *skb,
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;

5
net/mac80211/mesh_pathtbl.c
View file

@ -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 ieee80211_sub_if_data *sdata)
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 ieee80211_sub_if_data *sdata)
err = -ENXIO;
enddel:
mesh_paths_generation++;
spin_unlock(&mesh_paths->hashwlock[hash_idx]);
read_unlock(&pathtbl_resize_lock);
return err;

2
net/mac80211/sta_info.c
View file

@ -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_info **sta)
}
local->num_sta--;
local->sta_generation++;
if (local->ops->sta_notify) {
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)

5
net/wireless/core.c
View file

@ -32,6 +32,7 @@ MODULE_DESCRIPTION("wireless configuration support");
* 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 *wiphy)
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(struct notifier_block * nb,
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(struct notifier_block * nb,
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);

2
net/wireless/core.h
View file

@ -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))

31
net/wireless/nl80211.c
View file

@ -408,6 +408,9 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
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_buff *msg, u32 pid, u32 seq, int flags,
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 sk_buff *skb, struct netlink_callback *
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 sk_buff *skb, struct netlink_callback *
}
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 sk_buff *msg, u32 pid, u32 seq,
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_buff *msg, u32 pid, u32 seq,
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_buff *msg, u32 pid, u32 seq, int flags,
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);

1
net/wireless/scan.c
View file

@ -562,6 +562,7 @@ void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
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);