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| author | Johannes Berg <johannes.berg@intel.com> | 2011-06-20 13:40:46 +0200 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2011-06-22 16:09:45 -0400 |
| commit | 670dc2833d144375eac36ad74111495a825a9288 (patch) | |
| tree | 12d5d3a925da562a6ba0497c47f4b55c71ff545b /net/netlink | |
| parent | c1c3daee97498f5d74bfd23531cfe23c8e14a619 (diff) | |
| download | linux-3.10-670dc2833d144375eac36ad74111495a825a9288.tar.gz linux-3.10-670dc2833d144375eac36ad74111495a825a9288.tar.bz2 linux-3.10-670dc2833d144375eac36ad74111495a825a9288.zip | |
netlink: advertise incomplete dumps
Consider the following situation:
* a dump that would show 8 entries, four in the first
round, and four in the second
* between the first and second rounds, 6 entries are
removed
* now the second round will not show any entry, and
even if there is a sequence/generation counter the
application will not know
To solve this problem, add a new flag NLM_F_DUMP_INTR
to the netlink header that indicates the dump wasn't
consistent, this flag can also be set on the MSG_DONE
message that terminates the dump, and as such above
situation can be detected.
To achieve this, add a sequence counter to the netlink
callback struct. Of course, netlink code still needs
to use this new functionality. The correct way to do
that is to always set cb->seq when a dumpit callback
is invoked and call nl_dump_check_consistent() for
each new message. The core code will also call this
function for the final MSG_DONE message.
To make it usable with generic netlink, a new function
genlmsg_nlhdr() is needed to obtain the netlink header
from the genetlink user header.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/af_netlink.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 6ef64adf736..a7ec8512f55 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1693,6 +1693,8 @@ static int netlink_dump(struct sock *sk) if (!nlh) goto errout_skb; + nl_dump_check_consistent(cb, nlh); + memcpy(nlmsg_data(nlh), &len, sizeof(len)); if (sk_filter(sk, skb)) |