nl80211: prepare for non-netdev wireless devs

In order to support a P2P device abstraction and
Bluetooth high-speed AMPs, we need to have a way
to identify virtual interfaces that don't have a
netdev associated.

Do this by adding a NL80211_ATTR_WDEV attribute
to identify a wdev which may or may not also be
a netdev.

To simplify things, use a 64-bit value with the
high 32 bits being the wiphy index for this new
wdev identifier in the nl80211 API.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

7 files changed, 144 insertions, 47 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index db961a59247..e791487ead3 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -771,6 +771,9 @@ enum nl80211_commands {
  * @NL80211_ATTR_IFNAME: network interface name
  * @NL80211_ATTR_IFTYPE: type of virtual interface, see &enum nl80211_iftype
  *
+ * @NL80211_ATTR_WDEV: wireless device identifier, used for pseudo-devices
+ *      that don't have a netdev (u64)
+ *
  * @NL80211_ATTR_MAC: MAC address (various uses)
  *
  * @NL80211_ATTR_KEY_DATA: (temporal) key data; for TKIP this consists of
@@ -1493,6 +1496,8 @@ enum nl80211_attrs {
 
         NL80211_ATTR_BG_SCAN_PERIOD,
 
+        NL80211_ATTR_WDEV,
+
         /* add attributes here, update the policy in nl80211.c */
 
         __NL80211_ATTR_AFTER_LAST,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 51f67a9003a..a14e6a40668 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2341,17 +2341,25 @@ struct cfg80211_internal_bss;
 struct cfg80211_cached_keys;
 
 /**
- * struct wireless_dev - wireless per-netdev state
+ * struct wireless_dev - wireless device state
  *
- * This structure must be allocated by the driver/stack
- * that uses the ieee80211_ptr field in struct net_device
- * (this is intentional so it can be allocated along with
- * the netdev.)
+ * For netdevs, this structure must be allocated by the driver
+ * that uses the ieee80211_ptr field in struct net_device (this
+ * is intentional so it can be allocated along with the netdev.)
+ * It need not be registered then as netdev registration will
+ * be intercepted by cfg80211 to see the new wireless device.
+ *
+ * For non-netdev uses, it must also be allocated by the driver
+ * in response to the cfg80211 callbacks that require it, as
+ * there's no netdev registration in that case it may not be
+ * allocated outside of callback operations that return it.
  *
  * @wiphy: pointer to hardware description
  * @iftype: interface type
  * @list: (private) Used to collect the interfaces
- * @netdev: (private) Used to reference back to the netdev
+ * @netdev: (private) Used to reference back to the netdev, may be %NULL
+ * @identifier: (private) Identifier used in nl80211 to identify this
+ *      wireless device if it has no netdev
  * @current_bss: (private) Used by the internal configuration code
  * @channel: (private) Used by the internal configuration code to track
  *      the user-set AP, monitor and WDS channel
@@ -2383,6 +2391,8 @@ struct wireless_dev {
         struct list_head list;
         struct net_device *netdev;
 
+        u32 identifier;
+
         struct list_head mgmt_registrations;
         spinlock_t mgmt_registrations_lock;
 
diff --git a/net/wireless/core.c b/net/wireless/core.c
index e42a97b5b97..b110a8a242d 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -176,7 +176,7 @@ int cfg80211_switch_netns(struct cfg80211_registered_device *rdev,
         if (!(rdev->wiphy.flags & WIPHY_FLAG_NETNS_OK))
                 return -EOPNOTSUPP;
 
-        list_for_each_entry(wdev, &rdev->netdev_list, list) {
+        list_for_each_entry(wdev, &rdev->wdev_list, list) {
                 wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
                 err = dev_change_net_namespace(wdev->netdev, net, "wlan%d");
                 if (err)
@@ -188,7 +188,7 @@ int cfg80211_switch_netns(struct cfg80211_registered_device *rdev,
                 /* failed -- clean up to old netns */
                 net = wiphy_net(&rdev->wiphy);
 
-                list_for_each_entry_continue_reverse(wdev, &rdev->netdev_list,
+                list_for_each_entry_continue_reverse(wdev, &rdev->wdev_list,
                                                      list) {
                         wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
                         err = dev_change_net_namespace(wdev->netdev, net,
@@ -226,7 +226,7 @@ static int cfg80211_rfkill_set_block(void *data, bool blocked)
         rtnl_lock();
         mutex_lock(&rdev->devlist_mtx);
 
-        list_for_each_entry(wdev, &rdev->netdev_list, list)
+        list_for_each_entry(wdev, &rdev->wdev_list, list)
                 dev_close(wdev->netdev);
 
         mutex_unlock(&rdev->devlist_mtx);
@@ -304,7 +304,7 @@ struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv)
         mutex_init(&rdev->mtx);
         mutex_init(&rdev->devlist_mtx);
         mutex_init(&rdev->sched_scan_mtx);
-        INIT_LIST_HEAD(&rdev->netdev_list);
+        INIT_LIST_HEAD(&rdev->wdev_list);
         spin_lock_init(&rdev->bss_lock);
         INIT_LIST_HEAD(&rdev->bss_list);
         INIT_WORK(&rdev->scan_done_wk, __cfg80211_scan_done);
@@ -622,7 +622,7 @@ void wiphy_unregister(struct wiphy *wiphy)
                 __count == 0; }));
 
         mutex_lock(&rdev->devlist_mtx);
-        BUG_ON(!list_empty(&rdev->netdev_list));
+        BUG_ON(!list_empty(&rdev->wdev_list));
         mutex_unlock(&rdev->devlist_mtx);
 
         /*
@@ -821,7 +821,8 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
                 spin_lock_init(&wdev->mgmt_registrations_lock);
 
                 mutex_lock(&rdev->devlist_mtx);
-                list_add_rcu(&wdev->list, &rdev->netdev_list);
+                wdev->identifier = ++rdev->wdev_id;
+                list_add_rcu(&wdev->list, &rdev->wdev_list);
                 rdev->devlist_generation++;
                 /* can only change netns with wiphy */
                 dev->features |= NETIF_F_NETNS_LOCAL;
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 377dc394f48..6b0170a5f05 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -47,11 +47,11 @@ struct cfg80211_registered_device {
         /* wiphy index, internal only */
         int wiphy_idx;
 
-        /* associate netdev list */
+        /* associated wireless interfaces */
         struct mutex devlist_mtx;
         /* protected by devlist_mtx or RCU */
-        struct list_head netdev_list;
-        int devlist_generation;
+        struct list_head wdev_list;
+        int devlist_generation, wdev_id;
         int opencount; /* also protected by devlist_mtx */
         wait_queue_head_t dev_wait;
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 2a5cdb60bc6..35a9b15289f 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -46,28 +46,60 @@ static struct genl_family nl80211_fam = {
         .post_doit = nl80211_post_doit,
 };
 
-/* internal helper: get rdev and dev */
-static int get_rdev_dev_by_ifindex(struct net *netns, struct nlattr **attrs,
-                                   struct cfg80211_registered_device **rdev,
-                                   struct net_device **dev)
+/* returns ERR_PTR values */
+static struct wireless_dev *
+__cfg80211_wdev_from_attrs(struct net *netns, struct nlattr **attrs)
 {
-        int ifindex;
+        struct cfg80211_registered_device *rdev;
+        struct wireless_dev *result = NULL;
+        bool have_ifidx = attrs[NL80211_ATTR_IFINDEX];
+        bool have_wdev_id = attrs[NL80211_ATTR_WDEV];
+        u64 wdev_id;
+        int wiphy_idx = -1;
+        int ifidx = -1;
 
-        if (!attrs[NL80211_ATTR_IFINDEX])
-                return -EINVAL;
+        assert_cfg80211_lock();
 
-        ifindex = nla_get_u32(attrs[NL80211_ATTR_IFINDEX]);
-        *dev = dev_get_by_index(netns, ifindex);
-        if (!*dev)
-                return -ENODEV;
+        if (!have_ifidx && !have_wdev_id)
+                return ERR_PTR(-EINVAL);
 
-        *rdev = cfg80211_get_dev_from_ifindex(netns, ifindex);
-        if (IS_ERR(*rdev)) {
-                dev_put(*dev);
-                return PTR_ERR(*rdev);
+        if (have_ifidx)
+                ifidx = nla_get_u32(attrs[NL80211_ATTR_IFINDEX]);
+        if (have_wdev_id) {
+                wdev_id = nla_get_u64(attrs[NL80211_ATTR_WDEV]);
+                wiphy_idx = wdev_id >> 32;
         }
 
-        return 0;
+        list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+                struct wireless_dev *wdev;
+
+                if (wiphy_net(&rdev->wiphy) != netns)
+                        continue;
+
+                if (have_wdev_id && rdev->wiphy_idx != wiphy_idx)
+                        continue;
+
+                mutex_lock(&rdev->devlist_mtx);
+                list_for_each_entry(wdev, &rdev->wdev_list, list) {
+                        if (have_ifidx && wdev->netdev &&
+                            wdev->netdev->ifindex == ifidx) {
+                                result = wdev;
+                                break;
+                        }
+                        if (have_wdev_id && wdev->identifier == (u32)wdev_id) {
+                                result = wdev;
+                                break;
+                        }
+                }
+                mutex_unlock(&rdev->devlist_mtx);
+
+                if (result)
+                        break;
+        }
+
+        if (result)
+                return result;
+        return ERR_PTR(-ENODEV);
 }
 
 static struct cfg80211_registered_device *
@@ -79,13 +111,40 @@ __cfg80211_rdev_from_attrs(struct net *netns, struct nlattr **attrs)
         assert_cfg80211_lock();
 
         if (!attrs[NL80211_ATTR_WIPHY] &&
-            !attrs[NL80211_ATTR_IFINDEX])
+            !attrs[NL80211_ATTR_IFINDEX] &&
+            !attrs[NL80211_ATTR_WDEV])
                 return ERR_PTR(-EINVAL);
 
         if (attrs[NL80211_ATTR_WIPHY])
                 rdev = cfg80211_rdev_by_wiphy_idx(
                                 nla_get_u32(attrs[NL80211_ATTR_WIPHY]));
 
+        if (attrs[NL80211_ATTR_WDEV]) {
+                u64 wdev_id = nla_get_u64(attrs[NL80211_ATTR_WDEV]);
+                struct wireless_dev *wdev;
+                bool found = false;
+
+                tmp = cfg80211_rdev_by_wiphy_idx(wdev_id >> 32);
+                if (tmp) {
+                        /* make sure wdev exists */
+                        mutex_lock(&tmp->devlist_mtx);
+                        list_for_each_entry(wdev, &tmp->wdev_list, list) {
+                                if (wdev->identifier != (u32)wdev_id)
+                                        continue;
+                                found = true;
+                                break;
+                        }
+                        mutex_unlock(&tmp->devlist_mtx);
+
+                        if (!found)
+                                tmp = NULL;
+
+                        if (rdev && tmp != rdev)
+                                return ERR_PTR(-EINVAL);
+                        rdev = tmp;
+                }
+        }
+
         if (attrs[NL80211_ATTR_IFINDEX]) {
                 int ifindex = nla_get_u32(attrs[NL80211_ATTR_IFINDEX]);
                 netdev = dev_get_by_index(netns, ifindex);
@@ -294,6 +353,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
         [NL80211_ATTR_NOACK_MAP] = { .type = NLA_U16 },
         [NL80211_ATTR_INACTIVITY_TIMEOUT] = { .type = NLA_U16 },
         [NL80211_ATTR_BG_SCAN_PERIOD] = { .type = NLA_U16 },
+        [NL80211_ATTR_WDEV] = { .type = NLA_U64 },
 };
 
 /* policy for the key attributes */
@@ -1674,6 +1734,8 @@ static int nl80211_send_iface(struct sk_buff *msg, u32 pid, u32 seq, int flags,
                               struct net_device *dev)
 {
         void *hdr;
+        u64 wdev_id = (u64)dev->ieee80211_ptr->identifier |
+                      ((u64)rdev->wiphy_idx << 32);
 
         hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_INTERFACE);
         if (!hdr)
@@ -1684,6 +1746,7 @@ static int nl80211_send_iface(struct sk_buff *msg, u32 pid, u32 seq, int flags,
             nla_put_string(msg, NL80211_ATTR_IFNAME, dev->name) ||
             nla_put_u32(msg, NL80211_ATTR_IFTYPE,
                         dev->ieee80211_ptr->iftype) ||
+            nla_put_u64(msg, NL80211_ATTR_WDEV, wdev_id) ||
             nla_put_u32(msg, NL80211_ATTR_GENERATION,
                         rdev->devlist_generation ^
                         (cfg80211_rdev_list_generation << 2)))
@@ -1724,7 +1787,7 @@ static int nl80211_dump_interface(struct sk_buff *skb, struct netlink_callback *
                 if_idx = 0;
 
                 mutex_lock(&rdev->devlist_mtx);
-                list_for_each_entry(wdev, &rdev->netdev_list, list) {
+                list_for_each_entry(wdev, &rdev->wdev_list, list) {
                         if (if_idx < if_start) {
                                 if_idx++;
                                 continue;
@@ -2350,7 +2413,7 @@ static bool nl80211_get_ap_channel(struct cfg80211_registered_device *rdev,
 
         mutex_lock(&rdev->devlist_mtx);
 
-        list_for_each_entry(wdev, &rdev->netdev_list, list) {
+        list_for_each_entry(wdev, &rdev->wdev_list, list) {
                 if (wdev->iftype != NL80211_IFTYPE_AP &&
                     wdev->iftype != NL80211_IFTYPE_P2P_GO)
                         continue;
@@ -6660,8 +6723,8 @@ static int nl80211_pre_doit(struct genl_ops *ops, struct sk_buff *skb,
                             struct genl_info *info)
 {
         struct cfg80211_registered_device *rdev;
+        struct wireless_dev *wdev;
         struct net_device *dev;
-        int err;
         bool rtnl = ops->internal_flags & NL80211_FLAG_NEED_RTNL;
 
         if (rtnl)
@@ -6676,21 +6739,39 @@ static int nl80211_pre_doit(struct genl_ops *ops, struct sk_buff *skb,
                 }
                 info->user_ptr[0] = rdev;
         } else if (ops->internal_flags & NL80211_FLAG_NEED_NETDEV) {
-                err = get_rdev_dev_by_ifindex(genl_info_net(info), info->attrs,
-                                              &rdev, &dev);
-                if (err) {
+                mutex_lock(&cfg80211_mutex);
+                wdev = __cfg80211_wdev_from_attrs(genl_info_net(info),
+                                                  info->attrs);
+                if (IS_ERR(wdev)) {
+                        mutex_unlock(&cfg80211_mutex);
                         if (rtnl)
                                 rtnl_unlock();
-                        return err;
+                        return PTR_ERR(wdev);
                 }
+
+                if (!wdev->netdev) {
+                        mutex_unlock(&cfg80211_mutex);
+                        if (rtnl)
+                                rtnl_unlock();
+                        return -EINVAL;
+                }
+
+                dev = wdev->netdev;
+                rdev = wiphy_to_dev(wdev->wiphy);
+
                 if (ops->internal_flags & NL80211_FLAG_CHECK_NETDEV_UP &&
                     !netif_running(dev)) {
-                        cfg80211_unlock_rdev(rdev);
-                        dev_put(dev);
+                        mutex_unlock(&cfg80211_mutex);
                         if (rtnl)
                                 rtnl_unlock();
                         return -ENETDOWN;
                 }
+
+                dev_hold(dev);
+                cfg80211_lock_rdev(rdev);
+
+                mutex_unlock(&cfg80211_mutex);
+
                 info->user_ptr[0] = rdev;
                 info->user_ptr[1] = dev;
         }
@@ -8483,7 +8564,7 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
         rcu_read_lock();
 
         list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list) {
-                list_for_each_entry_rcu(wdev, &rdev->netdev_list, list)
+                list_for_each_entry_rcu(wdev, &rdev->wdev_list, list)
                         cfg80211_mlme_unregister_socket(wdev, notify->pid);
                 if (rdev->ap_beacons_nlpid == notify->pid)
                         rdev->ap_beacons_nlpid = 0;
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index f7e937ff897..dec97981e68 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -51,7 +51,7 @@ static bool cfg80211_is_all_idle(void)
          */
         list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
                 cfg80211_lock_rdev(rdev);
-                list_for_each_entry(wdev, &rdev->netdev_list, list) {
+                list_for_each_entry(wdev, &rdev->wdev_list, list) {
                         wdev_lock(wdev);
                         if (wdev->sme_state != CFG80211_SME_IDLE)
                                 is_all_idle = false;
@@ -221,7 +221,7 @@ void cfg80211_conn_work(struct work_struct *work)
         cfg80211_lock_rdev(rdev);
         mutex_lock(&rdev->devlist_mtx);
 
-        list_for_each_entry(wdev, &rdev->netdev_list, list) {
+        list_for_each_entry(wdev, &rdev->wdev_list, list) {
                 wdev_lock(wdev);
                 if (!netif_running(wdev->netdev)) {
                         wdev_unlock(wdev);
diff --git a/net/wireless/util.c b/net/wireless/util.c
index e31f1dba79e..f7a0647bde9 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -793,7 +793,7 @@ void cfg80211_process_rdev_events(struct cfg80211_registered_device *rdev)
 
         mutex_lock(&rdev->devlist_mtx);
 
-        list_for_each_entry(wdev, &rdev->netdev_list, list)
+        list_for_each_entry(wdev, &rdev->wdev_list, list)
                 cfg80211_process_wdev_events(wdev);
 
         mutex_unlock(&rdev->devlist_mtx);
@@ -994,7 +994,7 @@ int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
 
         mutex_lock(&rdev->devlist_mtx);
 
-        list_for_each_entry(wdev, &rdev->netdev_list, list) {
+        list_for_each_entry(wdev, &rdev->wdev_list, list) {
                 if (!wdev->beacon_interval)
                         continue;
                 if (wdev->beacon_interval != beacon_int) {
@@ -1050,7 +1050,7 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
                 break;
         }
 
-        list_for_each_entry(wdev_iter, &rdev->netdev_list, list) {
+        list_for_each_entry(wdev_iter, &rdev->wdev_list, list) {
                 if (wdev_iter == wdev)
                         continue;
                 if (!netif_running(wdev_iter->netdev))