The following commit has been merged in the maint branch: commit d9a949325449db1eb7976b0ba4c0b70ecac718e8 Author: Simon Wunderlich siwu@hrz.tu-chemnitz.de Date: Wed Jan 19 20:01:43 2011 +0000
batman-adv: protect bonding with rcu locks
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
diff --git a/hard-interface.c b/hard-interface.c index f2131f4..e2b001a 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -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; diff --git a/originator.c b/originator.c index 71dfc24..a85eadc 100644 --- a/originator.c +++ b/originator.c @@ -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); } }
diff --git a/originator.h b/originator.h index edc64dc..360dfd1 100644 --- a/originator.h +++ b/originator.h @@ -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, diff --git a/routing.c b/routing.c index 7627ebe..1ad14da 100644 --- a/routing.c +++ b/routing.c @@ -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) { diff --git a/routing.h b/routing.h index a09d16f..e2a9872 100644 --- a/routing.h +++ b/routing.h @@ -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_ */ diff --git a/types.h b/types.h index ff70afc..1f833f0 100644 --- a/types.h +++ b/types.h @@ -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; }; diff --git a/unicast.c b/unicast.c index 2bc88db..29d13aa 100644 --- a/unicast.c +++ b/unicast.c @@ -304,6 +304,7 @@ 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) @@ -311,7 +312,6 @@ 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);