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authorJohannes Berg <johannes.berg@intel.com>2011-06-20 11:40:46 (GMT)
committerJohn W. Linville <linville@tuxdriver.com>2011-06-22 20:09:45 (GMT)
commit670dc2833d144375eac36ad74111495a825a9288 (patch)
tree12d5d3a925da562a6ba0497c47f4b55c71ff545b /net/netlink
parentc1c3daee97498f5d74bfd23531cfe23c8e14a619 (diff)
downloadlinux-670dc2833d144375eac36ad74111495a825a9288.tar.xz
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.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 6ef64ad..a7ec851 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))