From f5ea9120be2e5d5c846243416cfdce01d02f5836 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 7 Aug 2009 16:17:38 +0200 Subject: 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 --- net/wireless/core.c | 5 +++++ net/wireless/core.h | 2 ++ net/wireless/nl80211.c | 31 +++++++++++++++++++++---------- net/wireless/scan.c | 1 + 4 files changed, 29 insertions(+), 10 deletions(-) (limited to 'net/wireless') 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 @@ 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 92e0492..639db52 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 2ff7376..b3d5c1d 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 0ccf3a0..1bcb131 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); -- cgit v1.1