batman-adv: Make bat_priv->primary_if an rcu protected pointer
[pandora-kernel.git] / net / batman-adv / gateway_client.c
index 3cc4355..65f3953 100644 (file)
@@ -23,6 +23,7 @@
 #include "gateway_client.h"
 #include "gateway_common.h"
 #include "hard-interface.h"
+#include "originator.h"
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/udp.h>
@@ -42,61 +43,76 @@ static void gw_node_free_ref(struct gw_node *gw_node)
                call_rcu(&gw_node->rcu, gw_node_free_rcu);
 }
 
-void *gw_get_selected(struct bat_priv *bat_priv)
+static struct gw_node *gw_get_selected_gw_node(struct bat_priv *bat_priv)
 {
-       struct gw_node *curr_gateway_tmp;
-       struct orig_node *orig_node = NULL;
+       struct gw_node *gw_node;
 
        rcu_read_lock();
-       curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
-       if (!curr_gateway_tmp)
-               goto out;
-
-       orig_node = curr_gateway_tmp->orig_node;
-       if (!orig_node)
+       gw_node = rcu_dereference(bat_priv->curr_gw);
+       if (!gw_node)
                goto out;
 
-       if (!atomic_inc_not_zero(&orig_node->refcount))
-               orig_node = NULL;
+       if (!atomic_inc_not_zero(&gw_node->refcount))
+               gw_node = NULL;
 
 out:
        rcu_read_unlock();
-       return orig_node;
+       return gw_node;
 }
 
-void gw_deselect(struct bat_priv *bat_priv)
+struct orig_node *gw_get_selected_orig(struct bat_priv *bat_priv)
 {
        struct gw_node *gw_node;
+       struct orig_node *orig_node = NULL;
 
-       spin_lock_bh(&bat_priv->gw_list_lock);
-       gw_node = rcu_dereference(bat_priv->curr_gw);
-       rcu_assign_pointer(bat_priv->curr_gw, NULL);
-       spin_unlock_bh(&bat_priv->gw_list_lock);
+       gw_node = gw_get_selected_gw_node(bat_priv);
+       if (!gw_node)
+               goto out;
+
+       rcu_read_lock();
+       orig_node = gw_node->orig_node;
+       if (!orig_node)
+               goto unlock;
+
+       if (!atomic_inc_not_zero(&orig_node->refcount))
+               orig_node = NULL;
 
+unlock:
+       rcu_read_unlock();
+out:
        if (gw_node)
                gw_node_free_ref(gw_node);
+       return orig_node;
 }
 
 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
 {
        struct gw_node *curr_gw_node;
 
+       spin_lock_bh(&bat_priv->gw_list_lock);
+
        if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
                new_gw_node = NULL;
 
-       spin_lock_bh(&bat_priv->gw_list_lock);
-       curr_gw_node = rcu_dereference(bat_priv->curr_gw);
+       curr_gw_node = bat_priv->curr_gw;
        rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
-       spin_unlock_bh(&bat_priv->gw_list_lock);
 
        if (curr_gw_node)
                gw_node_free_ref(curr_gw_node);
+
+       spin_unlock_bh(&bat_priv->gw_list_lock);
+}
+
+void gw_deselect(struct bat_priv *bat_priv)
+{
+       gw_select(bat_priv, NULL);
 }
 
 void gw_election(struct bat_priv *bat_priv)
 {
        struct hlist_node *node;
-       struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
+       struct gw_node *gw_node, *curr_gw = NULL, *curr_gw_tmp = NULL;
+       struct neigh_node *router;
        uint8_t max_tq = 0;
        uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
        int down, up;
@@ -110,32 +126,25 @@ void gw_election(struct bat_priv *bat_priv)
        if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
                return;
 
-       rcu_read_lock();
-       curr_gw = rcu_dereference(bat_priv->curr_gw);
-       if (curr_gw) {
-               rcu_read_unlock();
-               return;
-       }
+       curr_gw = gw_get_selected_gw_node(bat_priv);
+       if (curr_gw)
+               goto out;
 
+       rcu_read_lock();
        if (hlist_empty(&bat_priv->gw_list)) {
-
-               if (curr_gw) {
-                       rcu_read_unlock();
-                       bat_dbg(DBG_BATMAN, bat_priv,
-                               "Removing selected gateway - "
-                               "no gateway in range\n");
-                       gw_deselect(bat_priv);
-               } else
-                       rcu_read_unlock();
-
-               return;
+               bat_dbg(DBG_BATMAN, bat_priv,
+                       "Removing selected gateway - "
+                       "no gateway in range\n");
+               gw_deselect(bat_priv);
+               goto unlock;
        }
 
        hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
-               if (!gw_node->orig_node->router)
+               if (gw_node->deleted)
                        continue;
 
-               if (gw_node->deleted)
+               router = orig_node_get_router(gw_node->orig_node);
+               if (!router)
                        continue;
 
                switch (atomic_read(&bat_priv->gw_sel_class)) {
@@ -143,15 +152,14 @@ void gw_election(struct bat_priv *bat_priv)
                        gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
                                             &down, &up);
 
-                       tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
-                                        gw_node->orig_node->router->tq_avg *
+                       tmp_gw_factor = (router->tq_avg * router->tq_avg *
                                         down * 100 * 100) /
                                         (TQ_LOCAL_WINDOW_SIZE *
                                         TQ_LOCAL_WINDOW_SIZE * 64);
 
                        if ((tmp_gw_factor > max_gw_factor) ||
                            ((tmp_gw_factor == max_gw_factor) &&
-                            (gw_node->orig_node->router->tq_avg > max_tq)))
+                            (router->tq_avg > max_tq)))
                                curr_gw_tmp = gw_node;
                        break;
 
@@ -163,19 +171,25 @@ void gw_election(struct bat_priv *bat_priv)
                          *     soon as a better gateway appears which has
                          *     $routing_class more tq points)
                          **/
-                       if (gw_node->orig_node->router->tq_avg > max_tq)
+                       if (router->tq_avg > max_tq)
                                curr_gw_tmp = gw_node;
                        break;
                }
 
-               if (gw_node->orig_node->router->tq_avg > max_tq)
-                       max_tq = gw_node->orig_node->router->tq_avg;
+               if (router->tq_avg > max_tq)
+                       max_tq = router->tq_avg;
 
                if (tmp_gw_factor > max_gw_factor)
                        max_gw_factor = tmp_gw_factor;
+
+               neigh_node_free_ref(router);
        }
 
        if (curr_gw != curr_gw_tmp) {
+               router = orig_node_get_router(curr_gw_tmp->orig_node);
+               if (!router)
+                       goto unlock;
+
                if ((curr_gw) && (!curr_gw_tmp))
                        bat_dbg(DBG_BATMAN, bat_priv,
                                "Removing selected gateway - "
@@ -186,48 +200,50 @@ void gw_election(struct bat_priv *bat_priv)
                                "(gw_flags: %i, tq: %i)\n",
                                curr_gw_tmp->orig_node->orig,
                                curr_gw_tmp->orig_node->gw_flags,
-                               curr_gw_tmp->orig_node->router->tq_avg);
+                               router->tq_avg);
                else
                        bat_dbg(DBG_BATMAN, bat_priv,
                                "Changing route to gateway %pM "
                                "(gw_flags: %i, tq: %i)\n",
                                curr_gw_tmp->orig_node->orig,
                                curr_gw_tmp->orig_node->gw_flags,
-                               curr_gw_tmp->orig_node->router->tq_avg);
+                               router->tq_avg);
 
+               neigh_node_free_ref(router);
                gw_select(bat_priv, curr_gw_tmp);
        }
 
+unlock:
        rcu_read_unlock();
+out:
+       if (curr_gw)
+               gw_node_free_ref(curr_gw);
 }
 
 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 {
-       struct gw_node *curr_gateway_tmp;
+       struct orig_node *curr_gw_orig;
+       struct neigh_node *router_gw = NULL, *router_orig = NULL;
        uint8_t gw_tq_avg, orig_tq_avg;
 
-       rcu_read_lock();
-       curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
-       if (!curr_gateway_tmp)
-               goto out_rcu;
-
-       if (!curr_gateway_tmp->orig_node)
-               goto deselect_rcu;
+       curr_gw_orig = gw_get_selected_orig(bat_priv);
+       if (!curr_gw_orig)
+               goto deselect;
 
-       if (!curr_gateway_tmp->orig_node->router)
-               goto deselect_rcu;
+       router_gw = orig_node_get_router(curr_gw_orig);
+       if (!router_gw)
+               goto deselect;
 
        /* this node already is the gateway */
-       if (curr_gateway_tmp->orig_node == orig_node)
-               goto out_rcu;
-
-       if (!orig_node->router)
-               goto out_rcu;
+       if (curr_gw_orig == orig_node)
+               goto out;
 
-       gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
-       rcu_read_unlock();
+       router_orig = orig_node_get_router(orig_node);
+       if (!router_orig)
+               goto out;
 
-       orig_tq_avg = orig_node->router->tq_avg;
+       gw_tq_avg = router_gw->tq_avg;
+       orig_tq_avg = router_orig->tq_avg;
 
        /* the TQ value has to be better */
        if (orig_tq_avg < gw_tq_avg)
@@ -245,16 +261,17 @@ void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
                "Restarting gateway selection: better gateway found (tq curr: "
                "%i, tq new: %i)\n",
                gw_tq_avg, orig_tq_avg);
-       goto deselect;
 
-out_rcu:
-       rcu_read_unlock();
-       goto out;
-deselect_rcu:
-       rcu_read_unlock();
 deselect:
        gw_deselect(bat_priv);
 out:
+       if (curr_gw_orig)
+               orig_node_free_ref(curr_gw_orig);
+       if (router_gw)
+               neigh_node_free_ref(router_gw);
+       if (router_orig)
+               neigh_node_free_ref(router_orig);
+
        return;
 }
 
@@ -291,7 +308,15 @@ void gw_node_update(struct bat_priv *bat_priv,
                    struct orig_node *orig_node, uint8_t new_gwflags)
 {
        struct hlist_node *node;
-       struct gw_node *gw_node;
+       struct gw_node *gw_node, *curr_gw;
+
+       /**
+        * Note: We don't need a NULL check here, since curr_gw never gets
+        * dereferenced. If curr_gw is NULL we also should not exit as we may
+        * have this gateway in our list (duplication check!) even though we
+        * have no currently selected gateway.
+        */
+       curr_gw = gw_get_selected_gw_node(bat_priv);
 
        rcu_read_lock();
        hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
@@ -312,22 +337,26 @@ void gw_node_update(struct bat_priv *bat_priv,
                                "Gateway %pM removed from gateway list\n",
                                orig_node->orig);
 
-                       if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
-                               rcu_read_unlock();
-                               gw_deselect(bat_priv);
-                               return;
-                       }
+                       if (gw_node == curr_gw)
+                               goto deselect;
                }
 
-               rcu_read_unlock();
-               return;
+               goto unlock;
        }
-       rcu_read_unlock();
 
        if (new_gwflags == 0)
-               return;
+               goto unlock;
 
        gw_node_add(bat_priv, orig_node, new_gwflags);
+       goto unlock;
+
+deselect:
+       gw_deselect(bat_priv);
+unlock:
+       rcu_read_unlock();
+
+       if (curr_gw)
+               gw_node_free_ref(curr_gw);
 }
 
 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
@@ -337,9 +366,12 @@ void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 
 void gw_node_purge(struct bat_priv *bat_priv)
 {
-       struct gw_node *gw_node;
+       struct gw_node *gw_node, *curr_gw;
        struct hlist_node *node, *node_tmp;
        unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
+       char do_deselect = 0;
+
+       curr_gw = gw_get_selected_gw_node(bat_priv);
 
        spin_lock_bh(&bat_priv->gw_list_lock);
 
@@ -350,41 +382,56 @@ void gw_node_purge(struct bat_priv *bat_priv)
                    atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
                        continue;
 
-               if (rcu_dereference(bat_priv->curr_gw) == gw_node)
-                       gw_deselect(bat_priv);
+               if (curr_gw == gw_node)
+                       do_deselect = 1;
 
                hlist_del_rcu(&gw_node->list);
                gw_node_free_ref(gw_node);
        }
 
-
        spin_unlock_bh(&bat_priv->gw_list_lock);
+
+       /* gw_deselect() needs to acquire the gw_list_lock */
+       if (do_deselect)
+               gw_deselect(bat_priv);
+
+       if (curr_gw)
+               gw_node_free_ref(curr_gw);
 }
 
+/**
+ * fails if orig_node has no router
+ */
 static int _write_buffer_text(struct bat_priv *bat_priv,
                              struct seq_file *seq, struct gw_node *gw_node)
 {
        struct gw_node *curr_gw;
-       int down, up, ret;
+       struct neigh_node *router;
+       int down, up, ret = -1;
 
        gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 
-       rcu_read_lock();
-       curr_gw = rcu_dereference(bat_priv->curr_gw);
+       router = orig_node_get_router(gw_node->orig_node);
+       if (!router)
+               goto out;
 
-       ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
-                      (curr_gw == gw_node ? "=>" : "  "),
-                      gw_node->orig_node->orig,
-                      gw_node->orig_node->router->tq_avg,
-                      gw_node->orig_node->router->addr,
-                      gw_node->orig_node->router->if_incoming->net_dev->name,
-                      gw_node->orig_node->gw_flags,
-                      (down > 2048 ? down / 1024 : down),
-                      (down > 2048 ? "MBit" : "KBit"),
-                      (up > 2048 ? up / 1024 : up),
-                      (up > 2048 ? "MBit" : "KBit"));
+       curr_gw = gw_get_selected_gw_node(bat_priv);
 
-       rcu_read_unlock();
+       ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
+                        (curr_gw == gw_node ? "=>" : "  "),
+                        gw_node->orig_node->orig,
+                        router->tq_avg, router->addr,
+                        router->if_incoming->net_dev->name,
+                        gw_node->orig_node->gw_flags,
+                        (down > 2048 ? down / 1024 : down),
+                        (down > 2048 ? "MBit" : "KBit"),
+                        (up > 2048 ? up / 1024 : up),
+                        (up > 2048 ? "MBit" : "KBit"));
+
+       neigh_node_free_ref(router);
+       if (curr_gw)
+               gw_node_free_ref(curr_gw);
+out:
        return ret;
 }
 
@@ -392,40 +439,42 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 {
        struct net_device *net_dev = (struct net_device *)seq->private;
        struct bat_priv *bat_priv = netdev_priv(net_dev);
+       struct hard_iface *primary_if;
        struct gw_node *gw_node;
        struct hlist_node *node;
-       int gw_count = 0;
-
-       if (!bat_priv->primary_if) {
+       int gw_count = 0, ret = 0;
 
-               return seq_printf(seq, "BATMAN mesh %s disabled - please "
-                                 "specify interfaces to enable it\n",
-                                 net_dev->name);
+       primary_if = primary_if_get_selected(bat_priv);
+       if (!primary_if) {
+               ret = seq_printf(seq, "BATMAN mesh %s disabled - please "
+                                "specify interfaces to enable it\n",
+                                net_dev->name);
+               goto out;
        }
 
-       if (bat_priv->primary_if->if_status != IF_ACTIVE) {
-
-               return seq_printf(seq, "BATMAN mesh %s disabled - "
-                                      "primary interface not active\n",
-                                      net_dev->name);
+       if (primary_if->if_status != IF_ACTIVE) {
+               ret = seq_printf(seq, "BATMAN mesh %s disabled - "
+                                "primary interface not active\n",
+                                net_dev->name);
+               goto out;
        }
 
        seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
                   "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
                   "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
                   "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
-                  bat_priv->primary_if->net_dev->name,
-                  bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
+                  primary_if->net_dev->name,
+                  primary_if->net_dev->dev_addr, net_dev->name);
 
        rcu_read_lock();
        hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
                if (gw_node->deleted)
                        continue;
 
-               if (!gw_node->orig_node->router)
+               /* fails if orig_node has no router */
+               if (_write_buffer_text(bat_priv, seq, gw_node) < 0)
                        continue;
 
-               _write_buffer_text(bat_priv, seq, gw_node);
                gw_count++;
        }
        rcu_read_unlock();
@@ -433,7 +482,10 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset)
        if (gw_count == 0)
                seq_printf(seq, "No gateways in range ...\n");
 
-       return 0;
+out:
+       if (primary_if)
+               hardif_free_ref(primary_if);
+       return ret;
 }
 
 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
@@ -442,6 +494,7 @@ int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
        struct iphdr *iphdr;
        struct ipv6hdr *ipv6hdr;
        struct udphdr *udphdr;
+       struct gw_node *curr_gw;
        unsigned int header_len = 0;
 
        if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
@@ -506,12 +559,11 @@ int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
        if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
                return -1;
 
-       rcu_read_lock();
-       if (!rcu_dereference(bat_priv->curr_gw)) {
-               rcu_read_unlock();
+       curr_gw = gw_get_selected_gw_node(bat_priv);
+       if (!curr_gw)
                return 0;
-       }
-       rcu_read_unlock();
 
+       if (curr_gw)
+               gw_node_free_ref(curr_gw);
        return 1;
 }