The ipv4 and device notifiers are called with RTNL mutex held.
The table walk can take some time, better not block other RTNL users.
'ip a' has been reported to block for up to 20 seconds when conntrack table
has many entries and device down events are frequent (e.g., PPP).
Reported-and-tested-by: Martin Zaharinov <micron10@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
masq_inet6_event is called asynchronously from system work queue,
because the inet6 notifier is atomic and nf_iterate_cleanup can sleep.
The ipv4 and device notifiers call nf_iterate_cleanup directly.
This is legal, but these notifiers are called with RTNL mutex held.
A large conntrack table with many devices coming and going will have severe
impact on the system usability, with 'ip a' blocking for several seconds.
This change places the defer code into a helper and makes it more
generic so ipv4 and ifdown notifiers can be converted to defer the
cleanup walk as well in a follow patch.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Only reason for having two different register functions was because of
ipt_MASQUERADE and ip6t_MASQUERADE being two different modules.
Previous patch merged those into xt_MASQUERADE, so we can merge this too.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Both are now implemented by nf_nat_masquerade.c, so no need to keep
different headers.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Otherwise, we get notifier list corruption.
This is the most simple fix: remove the device notifier call chain
from the ipv6 masquerade register function and handle it only
in the ipv4 version.
The better fix is merge
nf_nat_masquerade_ipv4/6_(un)register_notifier
into a single
nf_nat_masquerade_(un)register_notifiers
but to do this its needed to first merge the two masquerade modules
into a single xt_MASQUERADE.
Furthermore, we need to use different refcounts for ipv4/ipv6
until we can merge MASQUERADE.
Fixes: d1aca8ab31 ("netfilter: nat: merge ipv4 and ipv6 masquerade functionality")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
