diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-02-15 17:21:07 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2024-02-18 10:22:27 +0000 |
| commit | e898e4cd1aab271ca414f9ac6e08e4c761f6913c (patch) | |
| tree | da47f3451a95addb074c6cda6cd0ee72d71d5383 /net/ipv6 | |
| parent | 081a0e3b0d4c061419d3f4679dec9f68725b17e4 (diff) | |
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: 63998ac24f83 ("ipv6: provide addr and netconf dump consistency info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/addrconf.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 733ace18806c..5a839c5fb1a5 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -708,6 +708,22 @@ errout: 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]; |