From f5ea9120be2e5d5c846243416cfdce01d02f5836 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 7 Aug 2009 16:17:38 +0200 Subject: [PATCH] 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 Signed-off-by: John W. Linville --- 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(-) diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h index cb3dc6027fd9..a8d71ed43a0e 100644 --- a/include/linux/nl80211.h +++ b/include/linux/nl80211.h @@ -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 diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 1ee30fcd6fdc..de7d116acc3d 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -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; }; /** diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 4bbf5007799b..5608f6c68413 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -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 | diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 989591787aee..99433222bc5c 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -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; diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h index 2a2ed182cb7e..ce538814b9bd 100644 --- a/net/mac80211/mesh.h +++ b/net/mac80211/mesh.h @@ -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; diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c index 04b9e4d61b8e..431865a58622 100644 --- a/net/mac80211/mesh_pathtbl.c +++ b/net/mac80211/mesh_pathtbl.c @@ -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; diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index a360bceeba59..eec001491e66 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -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) diff --git a/net/wireless/core.c b/net/wireless/core.c index 1e189306560d..62e1ac00879b 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -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); diff --git a/net/wireless/core.h b/net/wireless/core.h index 92e0492b0e4d..639db52eeff7 100644 --- a/net/wireless/core.h +++ b/net/wireless/core.h @@ -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)) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 2ff7376f35a3..b3d5c1df08dd 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -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); diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 0ccf3a07dc02..1bcb1312bd94 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -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); -- 2.20.1