Re: [PATCH net-next v2 1/7] net: flow_offload: provision conntrack info in ct_metadata

On Tue 17 Jan 2023 at 15:42, Pablo Neira Ayuso [off-list ref] wrote:

Hi Vlad,

On Fri, Jan 13, 2023 at 05:55:42PM +0100, Vlad Buslov wrote:

quoted

In order to offload connections in other states besides "established" the
driver offload callbacks need to have access to connection conntrack info.
Extend flow offload intermediate representation data structure
flow_action_entry->ct_metadata with new enum ip_conntrack_info field and
fill it in tcf_ct_flow_table_add_action_meta() callback.

Reject offloading IP_CT_NEW connections for now by returning an error in
relevant driver callbacks based on value of ctinfo. Support for offloading
such connections will need to be added to the drivers afterwards.

Signed-off-by: Vlad Buslov <redacted>
---

Notes:
    Changes V1 -> V2:
    
    - Add missing include that caused compilation errors on certain configs.
    
    - Change naming in nfp driver as suggested by Simon and Baowen.

 .../ethernet/mellanox/mlx5/core/en/tc_ct.c    |  2 +-
 .../ethernet/netronome/nfp/flower/conntrack.c | 20 +++++++++++++++++++
 include/net/flow_offload.h                    |  2 ++
 net/sched/act_ct.c                            |  1 +
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
index 313df8232db7..8cad5cf3305d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c

@@ -1077,7 +1077,7 @@ mlx5_tc_ct_block_flow_offload_add(struct mlx5_ct_ft *ft,
 	int err;
 
 	meta_action = mlx5_tc_ct_get_ct_metadata_action(flow_rule);
-	if (!meta_action)
+	if (!meta_action || meta_action->ct_metadata.ctinfo == IP_CT_NEW)
 		return -EOPNOTSUPP;
 
 	spin_lock_bh(&ct_priv->ht_lock);

diff --git a/drivers/net/ethernet/netronome/nfp/flower/conntrack.c b/drivers/net/ethernet/netronome/nfp/flower/conntrack.c
index f693119541d5..f7569584b9d8 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/conntrack.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/conntrack.c

@@ -1964,6 +1964,23 @@ int nfp_fl_ct_stats(struct flow_cls_offload *flow,
 	return 0;
 }
 
+static bool
+nfp_fl_ct_offload_nft_supported(struct flow_cls_offload *flow)
+{
+	struct flow_rule *flow_rule = flow->rule;
+	struct flow_action *flow_action =
+		&flow_rule->action;
+	struct flow_action_entry *act;
+	int i;
+
+	flow_action_for_each(i, act, flow_action) {
+		if (act->id == FLOW_ACTION_CT_METADATA)
+			return act->ct_metadata.ctinfo != IP_CT_NEW;
+	}
+
+	return false;
+}
+
 static int
 nfp_fl_ct_offload_nft_flow(struct nfp_fl_ct_zone_entry *zt, struct flow_cls_offload *flow)
 {

@@ -1976,6 +1993,9 @@ nfp_fl_ct_offload_nft_flow(struct nfp_fl_ct_zone_entry *zt, struct flow_cls_offl
 	extack = flow->common.extack;
 	switch (flow->command) {
 	case FLOW_CLS_REPLACE:
+		if (!nfp_fl_ct_offload_nft_supported(flow))
+			return -EOPNOTSUPP;
+
 		/* Netfilter can request offload multiple times for the same
 		 * flow - protect against adding duplicates.
 		 */

diff --git a/include/net/flow_offload.h b/include/net/flow_offload.h
index 0400a0ac8a29..a6adaffb68fb 100644
--- a/include/net/flow_offload.h
+++ b/include/net/flow_offload.h

@@ -4,6 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/netlink.h>
+#include <linux/netfilter/nf_conntrack_common.h>
 #include <net/flow_dissector.h>
 
 struct flow_match {

@@ -288,6 +289,7 @@ struct flow_action_entry {
 		} ct;
 		struct {
 			unsigned long cookie;
+			enum ip_conntrack_info ctinfo;

Maybe you can use a bool here, only possible states that make sense
are new and established.

As Marcelo suggested we can just obtain same info from the cookie, so
there is no need for adding either ctinfo or a boolean here.

quoted

 			u32 mark;
 			u32 labels[4];
 			bool orig_dir;

diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
index 0ca2bb8ed026..515577f913a3 100644
--- a/net/sched/act_ct.c
+++ b/net/sched/act_ct.c

@@ -187,6 +187,7 @@ static void tcf_ct_flow_table_add_action_meta(struct nf_conn *ct,
 	/* aligns with the CT reference on the SKB nf_ct_set */
 	entry->ct_metadata.cookie = (unsigned long)ct | ctinfo;
 	entry->ct_metadata.orig_dir = dir == IP_CT_DIR_ORIGINAL;
+	entry->ct_metadata.ctinfo = ctinfo;
 
 	act_ct_labels = entry->ct_metadata.labels;
 	ct_labels = nf_ct_labels_find(ct);

-- 
2.38.1