| Message ID | 20201109072930.14048-1-nusiddiq@redhat.com |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] netfiler: conntrack: Add the option to set ct tcp flag - BE_LIBERAL per-ct basis. | expand |
| Context | Check | Description |
|---|---|---|
| jkicinski/cover_letter | success | Link |
| jkicinski/fixes_present | success | Link |
| jkicinski/patch_count | success | Link |
| jkicinski/tree_selection | success | Clearly marked for net-next |
| jkicinski/subject_prefix | success | Link |
| jkicinski/source_inline | success | Was 0 now: 0 |
| jkicinski/verify_signedoff | success | Link |
| jkicinski/module_param | success | Was 0 now: 0 |
| jkicinski/build_32bit | success | Errors and warnings before: 94 this patch: 94 |
| jkicinski/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| jkicinski/verify_fixes | success | Link |
| jkicinski/checkpatch | warning | WARNING: line length of 86 exceeds 80 columns WARNING: line length of 89 exceeds 80 columns |
| jkicinski/build_allmodconfig_warn | success | Errors and warnings before: 94 this patch: 94 |
| jkicinski/header_inline | success | Link |
| jkicinski/stable | success | Stable not CCed |
On Mon, 9 Nov 2020 12:59:30 +0530 nusiddiq@redhat.com wrote: > From: Numan Siddique <nusiddiq@redhat.com> > > 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@redhat.com/ > > Suggested-by: Florian Westphal <fw@strlen.de> > Signed-off-by: Numan Siddique <nusiddiq@redhat.com> Please repost Ccing Pablo & netfilter-devel.
nusiddiq@redhat.com <nusiddiq@redhat.com> wrote: > From: Numan Siddique <nusiddiq@redhat.com> > > 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@redhat.com/ > > Suggested-by: Florian Westphal <fw@strlen.de> > Signed-off-by: Numan Siddique <nusiddiq@redhat.com> > --- > 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.: 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);
On Tue, Nov 10, 2020 at 1:25 AM Jakub Kicinski <kuba@kernel.org> wrote: > > On Mon, 9 Nov 2020 12:59:30 +0530 nusiddiq@redhat.com wrote: > > From: Numan Siddique <nusiddiq@redhat.com> > > > > 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@redhat.com/ > > > > Suggested-by: Florian Westphal <fw@strlen.de> > > Signed-off-by: Numan Siddique <nusiddiq@redhat.com> > > Please repost Ccing Pablo & netfilter-devel. Thanks. I will repost. Numan >
On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal <fw@strlen.de> wrote: > > nusiddiq@redhat.com <nusiddiq@redhat.com> wrote: > > From: Numan Siddique <nusiddiq@redhat.com> > > > > 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@redhat.com/ > > > > Suggested-by: Florian Westphal <fw@strlen.de> > > Signed-off-by: Numan Siddique <nusiddiq@redhat.com> > > --- > > 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); >
Numan Siddique <nusiddiq@redhat.com> wrote: > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal <fw@strlen.de> 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.
On Tue, Nov 10, 2020 at 5:55 PM Florian Westphal <fw@strlen.de> wrote: > > Numan Siddique <nusiddiq@redhat.com> wrote: > > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal <fw@strlen.de> 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 >
Numan Siddique <nusiddiq@redhat.com> wrote: > On Tue, Nov 10, 2020 at 5:55 PM Florian Westphal <fw@strlen.de> wrote: > > > > Numan Siddique <nusiddiq@redhat.com> wrote: > > > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal <fw@strlen.de> 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.
On Tue, Nov 10, 2020 at 6:41 PM Florian Westphal <fw@strlen.de> wrote: > > Numan Siddique <nusiddiq@redhat.com> wrote: > > On Tue, Nov 10, 2020 at 5:55 PM Florian Westphal <fw@strlen.de> wrote: > > > > > > Numan Siddique <nusiddiq@redhat.com> wrote: > > > > On Tue, Nov 10, 2020 at 3:06 AM Florian Westphal <fw@strlen.de> 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 >
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) { switch (nf_ct_protonum(ct)) { case IPPROTO_TCP: + if (tmpl_proto) { + if (tmpl_proto->tcp.seen[0].flags & IP_CT_TCP_FLAG_BE_LIBERAL) + ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL; + + if (tmpl_proto->tcp.seen[1].flags & IP_CT_TCP_FLAG_BE_LIBERAL) + ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL; + } return nf_conntrack_tcp_packet(ct, skb, dataoff, ctinfo, state); case IPPROTO_UDP: @@ -1843,7 +1851,8 @@ nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state) goto out; } - ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state); + ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state, + tmpl ? &tmpl->proto : NULL); if (ret <= 0) { /* Invalid: inverse of the return code tells * the netfilter core what to do */ diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c index 4beb96139d77..64247be2b1d7 100644 --- a/net/openvswitch/conntrack.c +++ b/net/openvswitch/conntrack.c @@ -969,6 +969,7 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key, if (skb_nfct(skb)) nf_conntrack_put(skb_nfct(skb)); nf_conntrack_get(&tmpl->ct_general); + nf_ct_set_tcp_be_liberal(tmpl); nf_ct_set(skb, tmpl, IP_CT_NEW); }