mac80211: revamp virtual interface handling

This patch revamps the virtual interface handling and makes the
code much easier to follow. Fewer functions, better names, less
spaghetti code.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 153 insertions, 184 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index f2aefd4b8637..6cf121bebd7a 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -2,6 +2,7 @@
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
+ * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -17,39 +18,149 @@
 #include "debugfs_netdev.h"
 #include "mesh.h"
 
-void ieee80211_if_sdata_init(struct ieee80211_sub_if_data *sdata)
+/*
+ * Called when the netdev is removed or, by the code below, before
+ * the interface type changes.
+ */
+static void ieee80211_teardown_sdata(struct net_device *dev)
 {
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct ieee80211_local *local = sdata->local;
+        struct beacon_data *beacon;
+        struct sk_buff *skb;
+        int flushed;
         int i;
 
-        /* Default values for sub-interface parameters */
-        sdata->drop_unencrypted = 0;
+        ieee80211_debugfs_remove_netdev(sdata);
+
+        /* free extra data */
+        ieee80211_free_keys(sdata);
+
         for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
-                skb_queue_head_init(&sdata->fragments[i].skb_list);
+                __skb_queue_purge(&sdata->fragments[i].skb_list);
+        sdata->fragment_next = 0;
 
-        INIT_LIST_HEAD(&sdata->key_list);
+        switch (sdata->vif.type) {
+        case IEEE80211_IF_TYPE_AP:
+                beacon = sdata->u.ap.beacon;
+                rcu_assign_pointer(sdata->u.ap.beacon, NULL);
+                synchronize_rcu();
+                kfree(beacon);
 
-        sdata->force_unicast_rateidx = -1;
-        sdata->max_ratectrl_rateidx = -1;
+                while ((skb = skb_dequeue(&sdata->u.ap.ps_bc_buf))) {
+                        local->total_ps_buffered--;
+                        dev_kfree_skb(skb);
+                }
+
+                break;
+        case IEEE80211_IF_TYPE_MESH_POINT:
+                /* Allow compiler to elide mesh_rmc_free call. */
+                if (ieee80211_vif_is_mesh(&sdata->vif))
+                        mesh_rmc_free(dev);
+                /* fall through */
+        case IEEE80211_IF_TYPE_STA:
+        case IEEE80211_IF_TYPE_IBSS:
+                kfree(sdata->u.sta.extra_ie);
+                kfree(sdata->u.sta.assocreq_ies);
+                kfree(sdata->u.sta.assocresp_ies);
+                kfree_skb(sdata->u.sta.probe_resp);
+                break;
+        case IEEE80211_IF_TYPE_WDS:
+        case IEEE80211_IF_TYPE_VLAN:
+        case IEEE80211_IF_TYPE_MNTR:
+                break;
+        case IEEE80211_IF_TYPE_INVALID:
+                BUG();
+                break;
+        }
+
+        flushed = sta_info_flush(local, sdata);
+        WARN_ON(flushed);
 }
 
-static void ieee80211_if_sdata_deinit(struct ieee80211_sub_if_data *sdata)
+/*
+ * Helper function to initialise an interface to a specific type.
+ */
+static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
+                                  enum ieee80211_if_types type)
 {
-        int i;
+        struct ieee80211_if_sta *ifsta;
 
-        for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
-                __skb_queue_purge(&sdata->fragments[i].skb_list);
+        /* clear type-dependent union */
+        memset(&sdata->u, 0, sizeof(sdata->u));
+
+        /* and set some type-dependent values */
+        sdata->vif.type = type;
+
+        /* only monitor differs */
+        sdata->dev->type = ARPHRD_ETHER;
+
+        switch (type) {
+        case IEEE80211_IF_TYPE_AP:
+                skb_queue_head_init(&sdata->u.ap.ps_bc_buf);
+                INIT_LIST_HEAD(&sdata->u.ap.vlans);
+                break;
+        case IEEE80211_IF_TYPE_MESH_POINT:
+        case IEEE80211_IF_TYPE_STA:
+        case IEEE80211_IF_TYPE_IBSS:
+                ifsta = &sdata->u.sta;
+                INIT_WORK(&ifsta->work, ieee80211_sta_work);
+                setup_timer(&ifsta->timer, ieee80211_sta_timer,
+                            (unsigned long) sdata);
+                skb_queue_head_init(&ifsta->skb_queue);
+
+                ifsta->capab = WLAN_CAPABILITY_ESS;
+                ifsta->auth_algs = IEEE80211_AUTH_ALG_OPEN |
+                        IEEE80211_AUTH_ALG_SHARED_KEY;
+                ifsta->flags |= IEEE80211_STA_CREATE_IBSS |
+                        IEEE80211_STA_AUTO_BSSID_SEL |
+                        IEEE80211_STA_AUTO_CHANNEL_SEL;
+                if (ieee80211_num_regular_queues(&sdata->local->hw) >= 4)
+                        ifsta->flags |= IEEE80211_STA_WMM_ENABLED;
+
+                if (ieee80211_vif_is_mesh(&sdata->vif))
+                        ieee80211_mesh_init_sdata(sdata);
+                break;
+        case IEEE80211_IF_TYPE_MNTR:
+                sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP;
+                sdata->dev->hard_start_xmit = ieee80211_monitor_start_xmit;
+                sdata->u.mntr_flags = MONITOR_FLAG_CONTROL |
+                                      MONITOR_FLAG_OTHER_BSS;
+                break;
+        case IEEE80211_IF_TYPE_WDS:
+        case IEEE80211_IF_TYPE_VLAN:
+                break;
+        case IEEE80211_IF_TYPE_INVALID:
+                BUG();
+                break;
+        }
+
+        ieee80211_debugfs_add_netdev(sdata);
+}
+
+void ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
+                              enum ieee80211_if_types type)
+{
+        /* Purge and reset type-dependent state. */
+        ieee80211_teardown_sdata(sdata->dev);
+        ieee80211_setup_sdata(sdata, type);
+
+        /* reset some values that shouldn't be kept across type changes */
+        sdata->basic_rates = 0;
+        sdata->drop_unencrypted = 0;
+        sdata->sequence = 0;
 }
 
-/* Must be called with rtnl lock held. */
 int ieee80211_if_add(struct ieee80211_local *local, const char *name,
-                     struct net_device **new_dev, int type,
+                     struct net_device **new_dev, enum ieee80211_if_types type,
                      struct vif_params *params)
 {
         struct net_device *ndev;
         struct ieee80211_sub_if_data *sdata = NULL;
-        int ret;
+        int ret, i;
 
         ASSERT_RTNL();
+
         ndev = alloc_netdev(sizeof(*sdata) + local->hw.vif_data_size,
                             name, ieee80211_if_setup);
         if (!ndev)
@@ -74,18 +185,28 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
         /* don't use IEEE80211_DEV_TO_SUB_IF because it checks too much */
         sdata = netdev_priv(ndev);
         ndev->ieee80211_ptr = &sdata->wdev;
+
+        /* initialise type-independent data */
         sdata->wdev.wiphy = local->hw.wiphy;
-        sdata->vif.type = IEEE80211_IF_TYPE_AP;
-        sdata->dev = ndev;
         sdata->local = local;
-        ieee80211_if_sdata_init(sdata);
+        sdata->dev = ndev;
+
+        for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
+                skb_queue_head_init(&sdata->fragments[i].skb_list);
+
+        INIT_LIST_HEAD(&sdata->key_list);
+
+        sdata->force_unicast_rateidx = -1;
+        sdata->max_ratectrl_rateidx = -1;
+
+        /* setup type-dependent data */
+        ieee80211_setup_sdata(sdata, type);
 
         ret = register_netdevice(ndev);
         if (ret)
                 goto fail;
 
-        ieee80211_debugfs_add_netdev(sdata);
-        ieee80211_if_set_type(ndev, type);
+        ndev->uninit = ieee80211_teardown_sdata;
 
         if (ieee80211_vif_is_mesh(&sdata->vif) &&
             params && params->mesh_id_len)
@@ -93,11 +214,6 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
                                              params->mesh_id_len,
                                              params->mesh_id);
 
-        /* we're under RTNL so all this is fine */
-        if (unlikely(local->reg_state == IEEE80211_DEV_UNREGISTERED)) {
-                __ieee80211_if_del(local, sdata);
-                return -ENODEV;
-        }
         list_add_tail_rcu(&sdata->list, &local->interfaces);
 
         if (new_dev)
@@ -105,181 +221,34 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
 
         return 0;
 
-fail:
+ fail:
         free_netdev(ndev);
         return ret;
 }
 
-void ieee80211_if_set_type(struct net_device *dev, int type)
+void ieee80211_if_remove(struct net_device *dev)
 {
         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
-        int oldtype = sdata->vif.type;
-
-        /*
-         * Called even when register_netdevice fails, it would
-         * oops if assigned before initialising the rest.
-         */
-        dev->uninit = ieee80211_if_reinit;
-
-        /* most have no BSS pointer */
-        sdata->bss = NULL;
-        sdata->vif.type = type;
-
-        sdata->basic_rates = 0;
-
-        switch (type) {
-        case IEEE80211_IF_TYPE_WDS:
-        case IEEE80211_IF_TYPE_VLAN:
-                /* nothing special */
-                break;
-        case IEEE80211_IF_TYPE_AP:
-                skb_queue_head_init(&sdata->u.ap.ps_bc_buf);
-                INIT_LIST_HEAD(&sdata->u.ap.vlans);
-                break;
-        case IEEE80211_IF_TYPE_MESH_POINT:
-        case IEEE80211_IF_TYPE_STA:
-        case IEEE80211_IF_TYPE_IBSS: {
-                struct ieee80211_if_sta *ifsta;
-
-                ifsta = &sdata->u.sta;
-                INIT_WORK(&ifsta->work, ieee80211_sta_work);
-                setup_timer(&ifsta->timer, ieee80211_sta_timer,
-                            (unsigned long) sdata);
-                skb_queue_head_init(&ifsta->skb_queue);
-
-                ifsta->capab = WLAN_CAPABILITY_ESS;
-                ifsta->auth_algs = IEEE80211_AUTH_ALG_OPEN |
-                        IEEE80211_AUTH_ALG_SHARED_KEY;
-                ifsta->flags |= IEEE80211_STA_CREATE_IBSS |
-                        IEEE80211_STA_AUTO_BSSID_SEL |
-                        IEEE80211_STA_AUTO_CHANNEL_SEL;
-                if (ieee80211_num_regular_queues(&sdata->local->hw) >= 4)
-                        ifsta->flags |= IEEE80211_STA_WMM_ENABLED;
-
-                if (ieee80211_vif_is_mesh(&sdata->vif))
-                        ieee80211_mesh_init_sdata(sdata);
-                break;
-        }
-        case IEEE80211_IF_TYPE_MNTR:
-                dev->type = ARPHRD_IEEE80211_RADIOTAP;
-                dev->hard_start_xmit = ieee80211_monitor_start_xmit;
-                sdata->u.mntr_flags = MONITOR_FLAG_CONTROL |
-                                      MONITOR_FLAG_OTHER_BSS;
-                break;
-        case IEEE80211_IF_TYPE_INVALID:
-                BUG();
-                break;
-        }
-        ieee80211_debugfs_change_if_type(sdata, oldtype);
-}
-
-/* Must be called with rtnl lock held. */
-void ieee80211_if_reinit(struct net_device *dev)
-{
-        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
-        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
-        struct sk_buff *skb;
-        int flushed;
 
         ASSERT_RTNL();
 
-        ieee80211_free_keys(sdata);
-
-        ieee80211_if_sdata_deinit(sdata);
-
-        /* Need to handle mesh specially to allow eliding the function call */
-        if (ieee80211_vif_is_mesh(&sdata->vif))
-                mesh_rmc_free(dev);
-
-        switch (sdata->vif.type) {
-        case IEEE80211_IF_TYPE_INVALID:
-                /* cannot happen */
-                WARN_ON(1);
-                break;
-        case IEEE80211_IF_TYPE_AP: {
-                struct beacon_data *beacon;
-
-                beacon = sdata->u.ap.beacon;
-                rcu_assign_pointer(sdata->u.ap.beacon, NULL);
-                synchronize_rcu();
-                kfree(beacon);
-
-                while ((skb = skb_dequeue(&sdata->u.ap.ps_bc_buf))) {
-                        local->total_ps_buffered--;
-                        dev_kfree_skb(skb);
-                }
-
-                break;
-        }
-        case IEEE80211_IF_TYPE_WDS:
-        case IEEE80211_IF_TYPE_VLAN:
-                /* nothing to do */
-                break;
-        case IEEE80211_IF_TYPE_MESH_POINT:
-        case IEEE80211_IF_TYPE_STA:
-        case IEEE80211_IF_TYPE_IBSS:
-                kfree(sdata->u.sta.extra_ie);
-                sdata->u.sta.extra_ie = NULL;
-                kfree(sdata->u.sta.assocreq_ies);
-                sdata->u.sta.assocreq_ies = NULL;
-                kfree(sdata->u.sta.assocresp_ies);
-                sdata->u.sta.assocresp_ies = NULL;
-                if (sdata->u.sta.probe_resp) {
-                        dev_kfree_skb(sdata->u.sta.probe_resp);
-                        sdata->u.sta.probe_resp = NULL;
-                }
-
-                break;
-        case IEEE80211_IF_TYPE_MNTR:
-                dev->type = ARPHRD_ETHER;
-                break;
-        }
-
-        flushed = sta_info_flush(local, sdata);
-        WARN_ON(flushed);
-
-        memset(&sdata->u, 0, sizeof(sdata->u));
-        ieee80211_if_sdata_init(sdata);
-}
-
-/* Must be called with rtnl lock held. */
-void __ieee80211_if_del(struct ieee80211_local *local,
-                        struct ieee80211_sub_if_data *sdata)
-{
-        struct net_device *dev = sdata->dev;
-
-        ieee80211_debugfs_remove_netdev(sdata);
+        list_del_rcu(&sdata->list);
+        synchronize_rcu();
         unregister_netdevice(dev);
-        /*
-         * The net_device will be freed by its destructor,
-         * i.e. ieee80211_if_free.
-         */
 }
 
-/* Must be called with rtnl lock held. */
-int ieee80211_if_remove(struct net_device *dev, const char *name, int id)
+/*
+ * Remove all interfaces, may only be called at hardware unregistration
+ * time because it doesn't do RCU-safe list removals.
+ */
+void ieee80211_remove_interfaces(struct ieee80211_local *local)
 {
-        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
-        struct ieee80211_sub_if_data *sdata, *n;
+        struct ieee80211_sub_if_data *sdata, *tmp;
 
         ASSERT_RTNL();
 
-        list_for_each_entry_safe(sdata, n, &local->interfaces, list) {
-                if ((sdata->vif.type == id || id == -1) &&
-                    strcmp(name, sdata->dev->name) == 0) {
-                        list_del_rcu(&sdata->list);
-                        synchronize_rcu();
-                        __ieee80211_if_del(local, sdata);
-                        return 0;
-                }
+        list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) {
+                list_del(&sdata->list);
+                unregister_netdevice(sdata->dev);
         }
-        return -ENODEV;
-}
-
-void ieee80211_if_free(struct net_device *dev)
-{
-        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
-
-        ieee80211_if_sdata_deinit(sdata);
-        free_netdev(dev);
 }