batman-adv: Make orig_node->router an rcu protected pointer
[cascardo/linux.git] / net / batman-adv / gateway_client.c
index 3cc4355..42a8a7b 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>
@@ -42,7 +43,7 @@ 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)
+struct orig_node *gw_get_selected(struct bat_priv *bat_priv)
 {
        struct gw_node *curr_gateway_tmp;
        struct orig_node *orig_node = NULL;
@@ -97,6 +98,7 @@ void gw_election(struct bat_priv *bat_priv)
 {
        struct hlist_node *node;
        struct gw_node *gw_node, *curr_gw, *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;
@@ -132,10 +134,11 @@ void gw_election(struct bat_priv *bat_priv)
        }
 
        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 +146,14 @@ 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 +165,25 @@ 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 out;
+
                if ((curr_gw) && (!curr_gw_tmp))
                        bat_dbg(DBG_BATMAN, bat_priv,
                                "Removing selected gateway - "
@@ -186,48 +194,47 @@ 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);
        }
 
+out:
        rcu_read_unlock();
 }
 
 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;
+       curr_gw_orig = gw_get_selected(bat_priv);
+       if (!curr_gw_orig)
+               goto deselect;
 
-       if (!curr_gateway_tmp->orig_node)
-               goto deselect_rcu;
-
-       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 +252,17 @@ 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;
 }
 
@@ -361,23 +369,30 @@ void gw_node_purge(struct bat_priv *bat_priv)
        spin_unlock_bh(&bat_priv->gw_list_lock);
 }
 
+/**
+ * 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);
 
+       router = orig_node_get_router(gw_node->orig_node);
+       if (!router)
+               goto out;
+
        rcu_read_lock();
        curr_gw = rcu_dereference(bat_priv->curr_gw);
 
        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,
+                      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"),
@@ -385,6 +400,8 @@ static int _write_buffer_text(struct bat_priv *bat_priv,
                       (up > 2048 ? "MBit" : "KBit"));
 
        rcu_read_unlock();
+       neigh_node_free_ref(router);
+out:
        return ret;
 }
 
@@ -422,10 +439,10 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset)
                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();