Commit e898e4cd authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv6: properly combine dev_base_seq and ipv6.dev_addr_genid 



net->dev_base_seq and ipv6.dev_addr_genid are monotonically increasing.

If we XOR their values, we could miss to detect if both values
were changed with the same amount.

Fixes: 63998ac2 ("ipv6: provide addr and netconf dump consistency info")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 081a0e3b

net/ipv6/addrconf.c

+18 −3
Original line number Diff line number Diff line
@@ -708,6 +708,22 @@ static int inet6_netconf_get_devconf(struct sk_buff *in_skb, 
	return err;

}



/* Combine dev_addr_genid and dev_base_seq to detect changes.

 */

static u32 inet6_base_seq(const struct net *net)

{

	u32 res = atomic_read(&net->ipv6.dev_addr_genid) +

		  net->dev_base_seq;



	/* Must not return 0 (see nl_dump_check_consistent()).

	 * Chose a value far away from 0.

	 */

	if (!res)

		res = 0x80000000;

	return res;

}





static int inet6_netconf_dump_devconf(struct sk_buff *skb,

				      struct netlink_callback *cb)

{
@@ -741,8 +757,7 @@ static int inet6_netconf_dump_devconf(struct sk_buff *skb, 
		idx = 0;

		head = &net->dev_index_head[h];

		rcu_read_lock();

		cb->seq = atomic_read(&net->ipv6.dev_addr_genid) ^

			  net->dev_base_seq;

		cb->seq = inet6_base_seq(net);

		hlist_for_each_entry_rcu(dev, head, index_hlist) {

			if (idx < s_idx)

				goto cont;
@@ -5362,7 +5377,7 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb, 
	}



	rcu_read_lock();

	cb->seq = atomic_read(&tgt_net->ipv6.dev_addr_genid) ^ tgt_net->dev_base_seq;

	cb->seq = inet6_base_seq(tgt_net);

	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {

		idx = 0;

		head = &tgt_net->dev_index_head[h];