Commit 081a0e3b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv4: properly combine dev_base_seq and ipv4.dev_addr_genid 



net->dev_base_seq and ipv4.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: 0465277f ("ipv4: provide addr and netconf dump consistency info")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 97dde840

net/ipv4/devinet.c

+17 −4
Original line number Diff line number Diff line
@@ -1825,6 +1825,21 @@ static int in_dev_dump_addr(struct in_device *in_dev, struct sk_buff *skb, 
	return err;

}



/* Combine dev_addr_genid and dev_base_seq to detect changes.

 */

static u32 inet_base_seq(const struct net *net)

{

	u32 res = atomic_read(&net->ipv4.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 inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)

{

	const struct nlmsghdr *nlh = cb->nlh;
@@ -1876,8 +1891,7 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb) 
		idx = 0;

		head = &tgt_net->dev_index_head[h];

		rcu_read_lock();

		cb->seq = atomic_read(&tgt_net->ipv4.dev_addr_genid) ^

			  tgt_net->dev_base_seq;

		cb->seq = inet_base_seq(tgt_net);

		hlist_for_each_entry_rcu(dev, head, index_hlist) {

			if (idx < s_idx)

				goto cont;
@@ -2278,8 +2292,7 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, 
		idx = 0;

		head = &net->dev_index_head[h];

		rcu_read_lock();

		cb->seq = atomic_read(&net->ipv4.dev_addr_genid) ^

			  net->dev_base_seq;

		cb->seq = inet_base_seq(net);

		hlist_for_each_entry_rcu(dev, head, index_hlist) {

			if (idx < s_idx)

				goto cont;