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Commit a4c135c5 authored by Simon Wunderlich's avatar Simon Wunderlich Committed by Marek Lindner
Browse files

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: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarMarek Lindner <lindner_marek@yahoo.de>
parent 2ae2daf6

net/batman-adv/originator.c

+21 −4
Original line number Diff line number Diff line
@@ -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);

		}

	}

net/batman-adv/originator.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

net/batman-adv/routing.c

+163 −150
Original line number Diff line number Diff line
@@ -271,6 +271,101 @@ static int is_bidirectional_neigh(struct orig_node *orig_node, 
	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);
@@ -497,119 +594,6 @@ static char count_real_packets(struct ethhdr *ethhdr, 
	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,
@@ -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);



		router = best_router;

			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;

				}

		}



		/* 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) {

net/batman-adv/routing.h

+4 −2
Original line number Diff line number Diff line
@@ -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_ */

net/batman-adv/types.h

+4 −5
Original line number Diff line number Diff line
@@ -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;

};