batman-adv: protect bonding with rcu locks
authorSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Wed, 19 Jan 2011 20:01:43 +0000 (20:01 +0000)
committerMarek Lindner <lindner_marek@yahoo.de>
Sat, 5 Mar 2011 11:50:01 +0000 (12:50 +0100)
bonding / alternating candidates need to be secured by rcu locks
as well. This patch therefore converts the bonding list
from a plain pointer list to a rcu securable lists and references
the bonding candidates.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
net/batman-adv/hard-interface.c
net/batman-adv/originator.c
net/batman-adv/originator.h
net/batman-adv/routing.c
net/batman-adv/routing.h
net/batman-adv/types.h
net/batman-adv/unicast.c

index f2131f45aa9bb9560168215da1d616c611f1c4b2..e2b001ad45c4abae4dd5a03c772b570152532ff3 100644 (file)
@@ -271,7 +271,7 @@ static void hardif_activate_interface(struct batman_if *batman_if)
 static void hardif_deactivate_interface(struct batman_if *batman_if)
 {
        if ((batman_if->if_status != IF_ACTIVE) &&
-          (batman_if->if_status != IF_TO_BE_ACTIVATED))
+           (batman_if->if_status != IF_TO_BE_ACTIVATED))
                return;
 
        batman_if->if_status = IF_INACTIVE;
index 71dfc24e961ba777f5cc5580a77fe87fa1a74379..a85eadca6b2db875d9fdc7a6833da17b91cb8281 100644 (file)
@@ -75,6 +75,14 @@ static void neigh_node_free_rcu(struct rcu_head *rcu)
        kref_put(&neigh_node->refcount, neigh_node_free_ref);
 }
 
+void neigh_node_free_rcu_bond(struct rcu_head *rcu)
+{
+       struct neigh_node *neigh_node;
+
+       neigh_node = container_of(rcu, struct neigh_node, rcu_bond);
+       kref_put(&neigh_node->refcount, neigh_node_free_ref);
+}
+
 struct neigh_node *create_neighbor(struct orig_node *orig_node,
                                   struct orig_node *orig_neigh_node,
                                   uint8_t *neigh,
@@ -91,6 +99,7 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
                return NULL;
 
        INIT_HLIST_NODE(&neigh_node->list);
+       INIT_LIST_HEAD(&neigh_node->bonding_list);
 
        memcpy(neigh_node->addr, neigh, ETH_ALEN);
        neigh_node->orig_node = orig_neigh_node;
@@ -106,13 +115,20 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
 void orig_node_free_ref(struct kref *refcount)
 {
        struct hlist_node *node, *node_tmp;
-       struct neigh_node *neigh_node;
+       struct neigh_node *neigh_node, *tmp_neigh_node;
        struct orig_node *orig_node;
 
        orig_node = container_of(refcount, struct orig_node, refcount);
 
        spin_lock_bh(&orig_node->neigh_list_lock);
 
+       /* for all bonding members ... */
+       list_for_each_entry_safe(neigh_node, tmp_neigh_node,
+                                &orig_node->bond_list, bonding_list) {
+               list_del_rcu(&neigh_node->bonding_list);
+               call_rcu(&neigh_node->rcu_bond, neigh_node_free_rcu_bond);
+       }
+
        /* for all neighbors towards this originator ... */
        hlist_for_each_entry_safe(neigh_node, node, node_tmp,
                                  &orig_node->neigh_list, list) {
@@ -207,6 +223,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
                return NULL;
 
        INIT_HLIST_HEAD(&orig_node->neigh_list);
+       INIT_LIST_HEAD(&orig_node->bond_list);
        spin_lock_init(&orig_node->ogm_cnt_lock);
        spin_lock_init(&orig_node->neigh_list_lock);
        kref_init(&orig_node->refcount);
@@ -220,6 +237,8 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
        orig_node->batman_seqno_reset = jiffies - 1
                                        - msecs_to_jiffies(RESET_PROTECTION_MS);
 
+       atomic_set(&orig_node->bond_candidates, 0);
+
        size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
 
        orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
@@ -295,6 +314,7 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,
                        neigh_purged = true;
 
                        hlist_del_rcu(&neigh_node->list);
+                       bonding_candidate_del(orig_node, neigh_node);
                        call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
                } else {
                        if ((!*best_neigh_node) ||
@@ -326,9 +346,6 @@ static bool purge_orig_node(struct bat_priv *bat_priv,
                                      best_neigh_node,
                                      orig_node->hna_buff,
                                      orig_node->hna_buff_len);
-                       /* update bonding candidates, we could have lost
-                        * some candidates. */
-                       update_bonding_candidates(orig_node);
                }
        }
 
index edc64dc33b12d44e3fad4ee48f78d1f45ecd5e44..360dfd19a32fca3c03e1895e9ce0f87372c462f4 100644 (file)
@@ -26,6 +26,7 @@ int originator_init(struct bat_priv *bat_priv);
 void originator_free(struct bat_priv *bat_priv);
 void purge_orig_ref(struct bat_priv *bat_priv);
 void orig_node_free_ref(struct kref *refcount);
+void neigh_node_free_rcu_bond(struct rcu_head *rcu);
 struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr);
 struct neigh_node *create_neighbor(struct orig_node *orig_node,
                                   struct orig_node *orig_neigh_node,
index 7627ebe50c4b9c1c34d0383abbd10e562885d917..1ad14da20839304132fb4f891590c1b7f6e45245 100644 (file)
@@ -271,6 +271,101 @@ out:
        return ret;
 }
 
+/* caller must hold the neigh_list_lock */
+void bonding_candidate_del(struct orig_node *orig_node,
+                          struct neigh_node *neigh_node)
+{
+       /* this neighbor is not part of our candidate list */
+       if (list_empty(&neigh_node->bonding_list))
+               goto out;
+
+       list_del_rcu(&neigh_node->bonding_list);
+       call_rcu(&neigh_node->rcu_bond, neigh_node_free_rcu_bond);
+       INIT_LIST_HEAD(&neigh_node->bonding_list);
+       atomic_dec(&orig_node->bond_candidates);
+
+out:
+       return;
+}
+
+static void bonding_candidate_add(struct orig_node *orig_node,
+                                 struct neigh_node *neigh_node)
+{
+       struct hlist_node *node;
+       struct neigh_node *tmp_neigh_node;
+       uint8_t best_tq, interference_candidate = 0;
+
+       spin_lock_bh(&orig_node->neigh_list_lock);
+
+       /* only consider if it has the same primary address ...  */
+       if (!compare_orig(orig_node->orig,
+                         neigh_node->orig_node->primary_addr))
+               goto candidate_del;
+
+       if (!orig_node->router)
+               goto candidate_del;
+
+       best_tq = orig_node->router->tq_avg;
+
+       /* ... and is good enough to be considered */
+       if (neigh_node->tq_avg < best_tq - BONDING_TQ_THRESHOLD)
+               goto candidate_del;
+
+       /**
+        * check if we have another candidate with the same mac address or
+        * interface. If we do, we won't select this candidate because of
+        * possible interference.
+        */
+       hlist_for_each_entry_rcu(tmp_neigh_node, node,
+                                &orig_node->neigh_list, list) {
+
+               if (tmp_neigh_node == neigh_node)
+                       continue;
+
+               /* we only care if the other candidate is even
+               * considered as candidate. */
+               if (list_empty(&tmp_neigh_node->bonding_list))
+                       continue;
+
+               if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
+                   (compare_orig(neigh_node->addr, tmp_neigh_node->addr))) {
+                       interference_candidate = 1;
+                       break;
+               }
+       }
+
+       /* don't care further if it is an interference candidate */
+       if (interference_candidate)
+               goto candidate_del;
+
+       /* this neighbor already is part of our candidate list */
+       if (!list_empty(&neigh_node->bonding_list))
+               goto out;
+
+       list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
+       kref_get(&neigh_node->refcount);
+       atomic_inc(&orig_node->bond_candidates);
+       goto out;
+
+candidate_del:
+       bonding_candidate_del(orig_node, neigh_node);
+
+out:
+       spin_unlock_bh(&orig_node->neigh_list_lock);
+       return;
+}
+
+/* copy primary address for bonding */
+static void bonding_save_primary(struct orig_node *orig_node,
+                                struct orig_node *orig_neigh_node,
+                                struct batman_packet *batman_packet)
+{
+       if (!(batman_packet->flags & PRIMARIES_FIRST_HOP))
+               return;
+
+       memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
+}
+
 static void update_orig(struct bat_priv *bat_priv,
                        struct orig_node *orig_node,
                        struct ethhdr *ethhdr,
@@ -339,6 +434,8 @@ static void update_orig(struct bat_priv *bat_priv,
                neigh_node->last_ttl = batman_packet->ttl;
        }
 
+       bonding_candidate_add(orig_node, neigh_node);
+
        tmp_hna_buff_len = (hna_buff_len > batman_packet->num_hna * ETH_ALEN ?
                            batman_packet->num_hna * ETH_ALEN : hna_buff_len);
 
@@ -497,123 +594,10 @@ err:
        return -1;
 }
 
-/* copy primary address for bonding */
-static void mark_bonding_address(struct orig_node *orig_node,
-                                struct orig_node *orig_neigh_node,
-                                struct batman_packet *batman_packet)
-
-{
-       if (batman_packet->flags & PRIMARIES_FIRST_HOP)
-               memcpy(orig_neigh_node->primary_addr,
-                      orig_node->orig, ETH_ALEN);
-
-       return;
-}
-
-/* mark possible bond.candidates in the neighbor list */
-void update_bonding_candidates(struct orig_node *orig_node)
-{
-       int candidates;
-       int interference_candidate;
-       int best_tq;
-       struct hlist_node *node, *node2;
-       struct neigh_node *tmp_neigh_node, *tmp_neigh_node2;
-       struct neigh_node *first_candidate, *last_candidate;
-
-       /* update the candidates for this originator */
-       if (!orig_node->router) {
-               orig_node->bond.candidates = 0;
-               return;
-       }
-
-       best_tq = orig_node->router->tq_avg;
-
-       /* update bond.candidates */
-
-       candidates = 0;
-
-       /* mark other nodes which also received "PRIMARIES FIRST HOP" packets
-        * as "bonding partner" */
-
-       /* first, zero the list */
-       rcu_read_lock();
-       hlist_for_each_entry_rcu(tmp_neigh_node, node,
-                                &orig_node->neigh_list, list) {
-               tmp_neigh_node->next_bond_candidate = NULL;
-       }
-       rcu_read_unlock();
-
-       first_candidate = NULL;
-       last_candidate = NULL;
-
-       rcu_read_lock();
-       hlist_for_each_entry_rcu(tmp_neigh_node, node,
-                                &orig_node->neigh_list, list) {
-
-               /* only consider if it has the same primary address ...  */
-               if (memcmp(orig_node->orig,
-                               tmp_neigh_node->orig_node->primary_addr,
-                               ETH_ALEN) != 0)
-                       continue;
-
-               /* ... and is good enough to be considered */
-               if (tmp_neigh_node->tq_avg < best_tq - BONDING_TQ_THRESHOLD)
-                       continue;
-
-               /* check if we have another candidate with the same
-                * mac address or interface. If we do, we won't
-                * select this candidate because of possible interference. */
-
-               interference_candidate = 0;
-               hlist_for_each_entry_rcu(tmp_neigh_node2, node2,
-                                        &orig_node->neigh_list, list) {
-
-                       if (tmp_neigh_node2 == tmp_neigh_node)
-                               continue;
-
-                       /* we only care if the other candidate is even
-                        * considered as candidate. */
-                       if (!tmp_neigh_node2->next_bond_candidate)
-                               continue;
-
-
-                       if ((tmp_neigh_node->if_incoming ==
-                               tmp_neigh_node2->if_incoming)
-                               || (memcmp(tmp_neigh_node->addr,
-                               tmp_neigh_node2->addr, ETH_ALEN) == 0)) {
-
-                               interference_candidate = 1;
-                               break;
-                       }
-               }
-               /* don't care further if it is an interference candidate */
-               if (interference_candidate)
-                       continue;
-
-               if (!first_candidate) {
-                       first_candidate = tmp_neigh_node;
-                       tmp_neigh_node->next_bond_candidate = first_candidate;
-               } else
-                       tmp_neigh_node->next_bond_candidate = last_candidate;
-
-               last_candidate = tmp_neigh_node;
-
-               candidates++;
-       }
-       rcu_read_unlock();
-
-       if (candidates > 0) {
-               first_candidate->next_bond_candidate = last_candidate;
-               orig_node->bond.selected = first_candidate;
-       }
-
-       orig_node->bond.candidates = candidates;
-}
-
 void receive_bat_packet(struct ethhdr *ethhdr,
-                               struct batman_packet *batman_packet,
-                               unsigned char *hna_buff, int hna_buff_len,
-                               struct batman_if *if_incoming)
+                       struct batman_packet *batman_packet,
+                       unsigned char *hna_buff, int hna_buff_len,
+                       struct batman_if *if_incoming)
 {
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batman_if *batman_if;
@@ -795,6 +779,8 @@ void receive_bat_packet(struct ethhdr *ethhdr,
        is_bidirectional = is_bidirectional_neigh(orig_node, orig_neigh_node,
                                                batman_packet, if_incoming);
 
+       bonding_save_primary(orig_node, orig_neigh_node, batman_packet);
+
        /* update ranking if it is not a duplicate or has the same
         * seqno and similar ttl as the non-duplicate */
        if (is_bidirectional &&
@@ -804,9 +790,6 @@ void receive_bat_packet(struct ethhdr *ethhdr,
                update_orig(bat_priv, orig_node, ethhdr, batman_packet,
                            if_incoming, hna_buff, hna_buff_len, is_duplicate);
 
-       mark_bonding_address(orig_node, orig_neigh_node, batman_packet);
-       update_bonding_candidates(orig_node);
-
        /* is single hop (direct) neighbor */
        if (is_single_hop_neigh) {
 
@@ -1095,14 +1078,15 @@ int recv_icmp_packet(struct sk_buff *skb, struct batman_if *recv_if)
 }
 
 /* find a suitable router for this originator, and use
- * bonding if possible. */
+ * bonding if possible. increases the found neighbors
+ * refcount.*/
 struct neigh_node *find_router(struct bat_priv *bat_priv,
                               struct orig_node *orig_node,
                               struct batman_if *recv_if)
 {
        struct orig_node *primary_orig_node;
        struct orig_node *router_orig;
-       struct neigh_node *router, *first_candidate, *best_router;
+       struct neigh_node *router, *first_candidate, *tmp_neigh_node;
        static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
        int bonding_enabled;
 
@@ -1114,18 +1098,25 @@ struct neigh_node *find_router(struct bat_priv *bat_priv,
 
        /* without bonding, the first node should
         * always choose the default router. */
-
        bonding_enabled = atomic_read(&bat_priv->bonding);
 
-       if ((!recv_if) && (!bonding_enabled))
-               return orig_node->router;
-
+       rcu_read_lock();
+       /* select default router to output */
+       router = orig_node->router;
        router_orig = orig_node->router->orig_node;
+       if (!router_orig) {
+               rcu_read_unlock();
+               return NULL;
+       }
+
+
+       if ((!recv_if) && (!bonding_enabled))
+               goto return_router;
 
        /* if we have something in the primary_addr, we can search
         * for a potential bonding candidate. */
        if (memcmp(router_orig->primary_addr, zero_mac, ETH_ALEN) == 0)
-               return orig_node->router;
+               goto return_router;
 
        /* find the orig_node which has the primary interface. might
         * even be the same as our router_orig in many cases */
@@ -1134,60 +1125,81 @@ struct neigh_node *find_router(struct bat_priv *bat_priv,
                                router_orig->orig, ETH_ALEN) == 0) {
                primary_orig_node = router_orig;
        } else {
-               rcu_read_lock();
                primary_orig_node = hash_find(bat_priv->orig_hash, compare_orig,
                                               choose_orig,
                                               router_orig->primary_addr);
-               rcu_read_unlock();
-
                if (!primary_orig_node)
-                       return orig_node->router;
+                       goto return_router;
        }
 
        /* with less than 2 candidates, we can't do any
         * bonding and prefer the original router. */
-
-       if (primary_orig_node->bond.candidates < 2)
-               return orig_node->router;
+       if (atomic_read(&primary_orig_node->bond_candidates) < 2)
+               goto return_router;
 
 
        /* all nodes between should choose a candidate which
         * is is not on the interface where the packet came
         * in. */
-       first_candidate = primary_orig_node->bond.selected;
-       router = first_candidate;
+
+       first_candidate = NULL;
+       router = NULL;
 
        if (bonding_enabled) {
                /* in the bonding case, send the packets in a round
                 * robin fashion over the remaining interfaces. */
-               do {
+
+               list_for_each_entry_rcu(tmp_neigh_node,
+                               &primary_orig_node->bond_list, bonding_list) {
+                       if (!first_candidate)
+                               first_candidate = tmp_neigh_node;
                        /* recv_if == NULL on the first node. */
-                       if (router->if_incoming != recv_if)
+                       if (tmp_neigh_node->if_incoming != recv_if) {
+                               router = tmp_neigh_node;
                                break;
+                       }
+               }
 
-                       router = router->next_bond_candidate;
-               } while (router != first_candidate);
+               /* use the first candidate if nothing was found. */
+               if (!router)
+                       router = first_candidate;
 
-               primary_orig_node->bond.selected = router->next_bond_candidate;
+               /* selected should point to the next element
+                * after the current router */
+               spin_lock_bh(&primary_orig_node->neigh_list_lock);
+               /* this is a list_move(), which unfortunately
+                * does not exist as rcu version */
+               list_del_rcu(&primary_orig_node->bond_list);
+               list_add_rcu(&primary_orig_node->bond_list,
+                               &router->bonding_list);
+               spin_unlock_bh(&primary_orig_node->neigh_list_lock);
 
        } else {
                /* if bonding is disabled, use the best of the
                 * remaining candidates which are not using
                 * this interface. */
-               best_router = first_candidate;
+               list_for_each_entry_rcu(tmp_neigh_node,
+                       &primary_orig_node->bond_list, bonding_list) {
+                       if (!first_candidate)
+                               first_candidate = tmp_neigh_node;
 
-               do {
                        /* recv_if == NULL on the first node. */
-                       if ((router->if_incoming != recv_if) &&
-                               (router->tq_avg > best_router->tq_avg))
-                                       best_router = router;
-
-                       router = router->next_bond_candidate;
-               } while (router != first_candidate);
+                       if (tmp_neigh_node->if_incoming != recv_if)
+                               /* if we don't have a router yet
+                                * or this one is better, choose it. */
+                               if ((!router) ||
+                               (tmp_neigh_node->tq_avg > router->tq_avg)) {
+                                       router = tmp_neigh_node;
+                               }
+               }
 
-               router = best_router;
+               /* use the first candidate if nothing was found. */
+               if (!router)
+                       router = first_candidate;
        }
-
+return_router:
+       kref_get(&router->refcount);
+       rcu_read_unlock();
        return router;
 }
 
@@ -1247,6 +1259,7 @@ int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
                               unicast_packet->dest));
        rcu_read_unlock();
 
+       /* find_router() increases neigh_nodes refcount if found. */
        router = find_router(bat_priv, orig_node, recv_if);
 
        if (!router) {
index a09d16f0c3ab6a64d96badbe89c0b3462a2c83ec..e2a9872a15892527fdbd3e493913a1842bf683de 100644 (file)
@@ -39,7 +39,9 @@ int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if);
 int recv_vis_packet(struct sk_buff *skb, struct batman_if *recv_if);
 int recv_bat_packet(struct sk_buff *skb, struct batman_if *recv_if);
 struct neigh_node *find_router(struct bat_priv *bat_priv,
-               struct orig_node *orig_node, struct batman_if *recv_if);
-void update_bonding_candidates(struct orig_node *orig_node);
+                              struct orig_node *orig_node,
+                              struct batman_if *recv_if);
+void bonding_candidate_del(struct orig_node *orig_node,
+                          struct neigh_node *neigh_node);
 
 #endif /* _NET_BATMAN_ADV_ROUTING_H_ */
index ff70afc376daa60ee344f8daf4361f243fc3a636..1f833f04222eb9502aeaf6576971d4f2f9c35ab6 100644 (file)
@@ -90,10 +90,8 @@ struct orig_node {
        struct bat_priv *bat_priv;
        unsigned long last_frag_packet;
        spinlock_t ogm_cnt_lock; /* protects ogm counter */
-       struct {
-               uint8_t candidates;
-               struct neigh_node *selected;
-       } bond;
+       atomic_t bond_candidates;
+       struct list_head bond_list;
 };
 
 struct gw_node {
@@ -116,11 +114,12 @@ struct neigh_node {
        uint8_t tq_index;
        uint8_t tq_avg;
        uint8_t last_ttl;
-       struct neigh_node *next_bond_candidate;
+       struct list_head bonding_list;
        unsigned long last_valid;
        unsigned long real_bits[NUM_WORDS];
        struct kref refcount;
        struct rcu_head rcu;
+       struct rcu_head rcu_bond;
        struct orig_node *orig_node;
        struct batman_if *if_incoming;
 };
index 4687027f1495adc84edd447f4d592a4319a57840..00bfeaf9ece37097eb0d4a3639048ecfcf916246 100644 (file)
@@ -299,6 +299,7 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
        if (!orig_node)
                orig_node = transtable_search(bat_priv, ethhdr->h_dest);
 
+       /* find_router() increases neigh_nodes refcount if found. */
        router = find_router(bat_priv, orig_node, NULL);
 
        if (!router)
@@ -306,7 +307,6 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 
        /* don't lock while sending the packets ... we therefore
                * copy the required data before sending */
-
        batman_if = router->if_incoming;
        memcpy(dstaddr, router->addr, ETH_ALEN);