Commit f8f2eb9d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

neighbour: add RCU protection to neigh_tables[] 



In order to remove RTNL protection from neightbl_dump_info()
and neigh_dump_info() later, we need to add
RCU protection to neigh_tables[].

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9fc31a92

net/core/neighbour.c

+19 −11
Original line number Diff line number Diff line
@@ -1771,7 +1771,7 @@ static void neigh_parms_destroy(struct neigh_parms *parms) 


static struct lock_class_key neigh_table_proxy_queue_class;



static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly;

static struct neigh_table __rcu *neigh_tables[NEIGH_NR_TABLES] __read_mostly;



void neigh_table_init(int index, struct neigh_table *tbl)

{
@@ -1828,13 +1828,19 @@ void neigh_table_init(int index, struct neigh_table *tbl) 
	tbl->last_flush = now;

	tbl->last_rand	= now + tbl->parms.reachable_time * 20;



	neigh_tables[index] = tbl;

	rcu_assign_pointer(neigh_tables[index], tbl);

}

EXPORT_SYMBOL(neigh_table_init);



/*

 * Only called from ndisc_cleanup(), which means this is dead code

 * because we no longer can unload IPv6 module.

 */

int neigh_table_clear(int index, struct neigh_table *tbl)

{

	neigh_tables[index] = NULL;

	RCU_INIT_POINTER(neigh_tables[index], NULL);

	synchronize_rcu();



	/* It is not clean... Fix it to unload IPv6 module safely */

	cancel_delayed_work_sync(&tbl->managed_work);

	cancel_delayed_work_sync(&tbl->gc_work);
@@ -1866,10 +1872,10 @@ static struct neigh_table *neigh_find_table(int family) 


	switch (family) {

	case AF_INET:

		tbl = neigh_tables[NEIGH_ARP_TABLE];

		tbl = rcu_dereference_rtnl(neigh_tables[NEIGH_ARP_TABLE]);

		break;

	case AF_INET6:

		tbl = neigh_tables[NEIGH_ND_TABLE];

		tbl = rcu_dereference_rtnl(neigh_tables[NEIGH_ND_TABLE]);

		break;

	}
@@ -2333,7 +2339,7 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, 
	ndtmsg = nlmsg_data(nlh);



	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {

		tbl = neigh_tables[tidx];

		tbl = rcu_dereference_rtnl(neigh_tables[tidx]);

		if (!tbl)

			continue;

		if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
@@ -2521,7 +2527,7 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb) 
	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {

		struct neigh_parms *p;



		tbl = neigh_tables[tidx];

		tbl = rcu_dereference_rtnl(neigh_tables[tidx]);

		if (!tbl)

			continue;
@@ -2881,7 +2887,7 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb) 
	s_t = cb->args[0];



	for (t = 0; t < NEIGH_NR_TABLES; t++) {

		tbl = neigh_tables[t];

		tbl = rcu_dereference_rtnl(neigh_tables[t]);



		if (!tbl)

			continue;
@@ -3145,14 +3151,15 @@ int neigh_xmit(int index, struct net_device *dev, 
	       const void *addr, struct sk_buff *skb)

{

	int err = -EAFNOSUPPORT;



	if (likely(index < NEIGH_NR_TABLES)) {

		struct neigh_table *tbl;

		struct neighbour *neigh;



		tbl = neigh_tables[index];

		if (!tbl)

			goto out;

		rcu_read_lock();

		tbl = rcu_dereference(neigh_tables[index]);

		if (!tbl)

			goto out_unlock;

		if (index == NEIGH_ARP_TABLE) {

			u32 key = *((u32 *)addr);
@@ -3168,6 +3175,7 @@ int neigh_xmit(int index, struct net_device *dev, 
			goto out_kfree_skb;

		}

		err = READ_ONCE(neigh->output)(neigh, skb);

out_unlock:

		rcu_read_unlock();

	}

	else if (index == NEIGH_LINK_TABLE) {