From a4c135c561106c397bae33455acfca4aa8065a30 Mon Sep 17 00:00:00 2001 From: Simon Wunderlich Date: Wed, 19 Jan 2011 20:01:43 +0000 Subject: 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 Signed-off-by: Marek Lindner --- net/batman-adv/routing.c | 313 ++++++++++++++++++++++++----------------------- 1 file changed, 163 insertions(+), 150 deletions(-) (limited to 'net/batman-adv/routing.c') diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index 7627ebe..1ad14da 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/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) { -- cgit v1.1