Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
On Tue, Nov 10, 2020 at 6:41 PM Florian Westphal wrote: > > Numan Siddique wrote: > > On Tue, Nov 10, 2020 at 5:55 PM Florian Westphal wrote: > > > > > > Numan Siddique wrote: > > > > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal wrote: > > > > 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(). > > > > > > Yes, it won't be set during nf_conntrack_in, thats why I suggested > > > to do it before confirming the connection. > > > > Sorry for the confusion. What I mean is - I tested your suggestion - i.e > > called > > nf_ct_set_tcp_be_liberal() before calling nf_conntrack_confirm(). > > > > Once the connection is established, for subsequent packets, openvswitch > > calls nf_conntrack_in() [1] to see if the packet is part of the > > existing connection or not (i.e ct.new or ct.est ) > > and if the packet happens to be out-of-window then skb->_nfct is set > > to NULL. And the tcp > > be flags set during confirmation are not reflected when > > nf_conntrack_in() calls resolve_normal_ct(). > > Can you debug where this happens? This looks very very wrong. > resolve_normal_ct() has no business to check any of those flags > (and I don't see where it uses them, it should only deal with the > tuples). > > The flags come into play when nf_conntrack_handle_packet() gets called > after resolve_normal_ct has found an entry, since that will end up > calling the tcp conntrack part. > > The entry found/returned by resolve_normal_ct should be the same > nf_conn entry that was confirmed earlier, i.e. it should be in "liberal" > mode. I debugged a bit. Calling nf_ct_set_tcp_be_liberal() in ct_commit doesn't work because - the first SYN packet during connection establishment is committed to the contract. - but tcp_in_window() calls tcp_options() which clears the tcp ct flags for the SYN and SYN-ACK packets. And hence the flags get cleared. So I think it should be enough if openvswitch calls nf_ct_set_tcp_be_liberal() once the connection is established. I posted v2. Request to take a look. Thanks Numan > ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
Numan Siddique wrote: > On Tue, Nov 10, 2020 at 5:55 PM Florian Westphal wrote: > > > > Numan Siddique wrote: > > > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal wrote: > > > 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(). > > > > Yes, it won't be set during nf_conntrack_in, thats why I suggested > > to do it before confirming the connection. > > Sorry for the confusion. What I mean is - I tested your suggestion - i.e > called > nf_ct_set_tcp_be_liberal() before calling nf_conntrack_confirm(). > > Once the connection is established, for subsequent packets, openvswitch > calls nf_conntrack_in() [1] to see if the packet is part of the > existing connection or not (i.e ct.new or ct.est ) > and if the packet happens to be out-of-window then skb->_nfct is set > to NULL. And the tcp > be flags set during confirmation are not reflected when > nf_conntrack_in() calls resolve_normal_ct(). Can you debug where this happens? This looks very very wrong. resolve_normal_ct() has no business to check any of those flags (and I don't see where it uses them, it should only deal with the tuples). The flags come into play when nf_conntrack_handle_packet() gets called after resolve_normal_ct has found an entry, since that will end up calling the tcp conntrack part. The entry found/returned by resolve_normal_ct should be the same nf_conn entry that was confirmed earlier, i.e. it should be in "liberal" mode. ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
On Tue, Nov 10, 2020 at 5:55 PM Florian Westphal wrote: > > Numan Siddique wrote: > > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal wrote: > > 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(). > > Yes, it won't be set during nf_conntrack_in, thats why I suggested > to do it before confirming the connection. Sorry for the confusion. What I mean is - I tested your suggestion - i.e called nf_ct_set_tcp_be_liberal() before calling nf_conntrack_confirm(). Once the connection is established, for subsequent packets, openvswitch calls nf_conntrack_in() [1] to see if the packet is part of the existing connection or not (i.e ct.new or ct.est ) and if the packet happens to be out-of-window then skb->_nfct is set to NULL. And the tcp be flags set during confirmation are not reflected 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 ? > > Yes, they are preserved when you set them after nf_conntrack_in(), else > we would already have trouble with hw flow offloading which needs to > turn off window checks as well. Looks they are not preserved for the openvswitch case. Probably openvswitch is doing something wrong. I will debug further and see what is going on. Please let me know if you have any further comments. Thanks Numan > ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
Numan Siddique wrote: > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal wrote: > 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(). Yes, it won't be set during nf_conntrack_in, thats why I suggested to do it before confirming the connection. > Would you expect that the tcp ct flags should have been preserved once > the connection is committed ? Yes, they are preserved when you set them after nf_conntrack_in(), else we would already have trouble with hw flow offloading which needs to turn off window checks as well. ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal wrote:
>
> nusid...@redhat.com wrote:
> > From: Numan Siddique
> >
> > 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-nusid...@redhat.com/
> >
> > Suggested-by: Florian Westphal
> > Signed-off-by: Numan Siddique
> > ---
> > 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 >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, >labels.value,
> >labels.mask);
> if (err)
> return err;
> +
> + if (nf_ct_protonum(ct) == IPPROTO_TCP)
> + nf_ct_set_tcp_be_liberal(ct);
>
___
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
On Tue, Nov 10, 2020 at 1:25 AM Jakub Kicinski wrote: > > On Mon, 9 Nov 2020 12:59:30 +0530 nusid...@redhat.com wrote: > > From: Numan Siddique > > > > 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-nusid...@redhat.com/ > > > > Suggested-by: Florian Westphal > > Signed-off-by: Numan Siddique > > Please repost Ccing Pablo & netfilter-devel. Thanks. I will repost. Numan > ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
nusid...@redhat.com wrote:
> From: Numan Siddique
>
> 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-nusid...@redhat.com/
>
> Suggested-by: Florian Westphal
> Signed-off-by: Numan Siddique
> ---
> 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 >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.:
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, >labels.value,
>labels.mask);
if (err)
return err;
+
+ if (nf_ct_protonum(ct) == IPPROTO_TCP)
+ nf_ct_set_tcp_be_liberal(ct);
___
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
Re: [ovs-dev] [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis.
On Mon, 9 Nov 2020 12:59:30 +0530 nusid...@redhat.com wrote: > From: Numan Siddique > > 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-nusid...@redhat.com/ > > Suggested-by: Florian Westphal > Signed-off-by: Numan Siddique Please repost Ccing Pablo & netfilter-devel. ___ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
