On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal <fw@xxxxxxxxx> wrote: > > nusiddiq@xxxxxxxxxx <nusiddiq@xxxxxxxxxx> wrote: > > From: Numan Siddique <nusiddiq@xxxxxxxxxx> > > > > Before calling nf_conntrack_in(), caller can set this flag in the > > connection template for a tcp packet and any errors in the > > tcp_in_window() will be ignored. > > > > A helper function - nf_ct_set_tcp_be_liberal(nf_conn) is added which > > sets this flag for both the directions of the nf_conn. > > > > openvswitch makes use of this feature so that any out of window tcp > > packets are not marked invalid. Prior to this there was no easy way > > to distinguish if conntracked packet is marked invalid because of > > tcp_in_window() check error or because it doesn't belong to an > > existing connection. > > > > An earlier attempt (see the link) tried to solve this problem for > > openvswitch in a different way. Florian Westphal instead suggested > > to be liberal in openvswitch for tcp packets. > > > > Link: https://patchwork.ozlabs.org/project/netdev/patch/20201006083355.121018-1-nusiddiq@xxxxxxxxxx/ > > > > Suggested-by: Florian Westphal <fw@xxxxxxxxx> > > Signed-off-by: Numan Siddique <nusiddiq@xxxxxxxxxx> > > --- > > include/net/netfilter/nf_conntrack_l4proto.h | 6 ++++++ > > net/netfilter/nf_conntrack_core.c | 13 +++++++++++-- > > net/openvswitch/conntrack.c | 1 + > > 3 files changed, 18 insertions(+), 2 deletions(-) > > > > diff --git a/include/net/netfilter/nf_conntrack_l4proto.h b/include/net/netfilter/nf_conntrack_l4proto.h > > index 88186b95b3c2..572ae8d2a622 100644 > > --- a/include/net/netfilter/nf_conntrack_l4proto.h > > +++ b/include/net/netfilter/nf_conntrack_l4proto.h > > @@ -203,6 +203,12 @@ static inline struct nf_icmp_net *nf_icmpv6_pernet(struct net *net) > > { > > return &net->ct.nf_ct_proto.icmpv6; > > } > > + > > +static inline void nf_ct_set_tcp_be_liberal(struct nf_conn *ct) > > +{ > > + ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL; > > + ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL; > > +} > > #endif > > > > #ifdef CONFIG_NF_CT_PROTO_DCCP > > diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c > > index 234b7cab37c3..8290c5b04e88 100644 > > --- a/net/netfilter/nf_conntrack_core.c > > +++ b/net/netfilter/nf_conntrack_core.c > > @@ -1748,10 +1748,18 @@ static int nf_conntrack_handle_packet(struct nf_conn *ct, > > struct sk_buff *skb, > > unsigned int dataoff, > > enum ip_conntrack_info ctinfo, > > - const struct nf_hook_state *state) > > + const struct nf_hook_state *state, > > + union nf_conntrack_proto *tmpl_proto) > > I would prefer if we could avoid adding yet another function argument. > > AFAICS its enough to call the new nf_ct_set_tcp_be_liberal() helper > before nf_conntrack_confirm() in ovs_ct_commit(), e.g.: Thanks for the comments. I actually tried this approach first, but it doesn't seem to work. I noticed that for the committed connections, the ct tcp flag - IP_CT_TCP_FLAG_BE_LIBERAL is not set when nf_conntrack_in() calls resolve_normal_ct(). Would you expect that the tcp ct flags should have been preserved once the connection is committed ? Thanks Numan > > diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c > --- a/net/openvswitch/conntrack.c > +++ b/net/openvswitch/conntrack.c > @@ -1235,10 +1235,13 @@ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key, > if (!nf_ct_is_confirmed(ct)) { > err = ovs_ct_init_labels(ct, key, &info->labels.value, > &info->labels.mask); > if (err) > return err; > + > + if (nf_ct_protonum(ct) == IPPROTO_TCP) > + nf_ct_set_tcp_be_liberal(ct); >
