diff options
| author | Eric Dumazet | 2024-02-15 17:21:06 +0000 |
|---|---|---|
| committer | David S. Miller | 2024-02-18 10:22:27 +0000 |
| commit | 081a0e3b0d4c061419d3f4679dec9f68725b17e4 (patch) | |
| tree | f17704eaff8487f821301435f259bc835454b8bc /net | |
| parent | 97dde84026339e4b4af9a6301f825d1828d7874b (diff) | |
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: 0465277f6b3f ("ipv4: provide addr and netconf dump consistency info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/devinet.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index ca0ff15dc8fa..bc74f131fe4d 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1825,6 +1825,21 @@ done: 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; |