sfc: functions to register for conntrack zone offload

Bind a stub callback to the netfilter flow table.

Reviewed-by: Pieter Jansen van Vuuren <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: Edward Cree <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/sfc/Makefile

···
 sfc-$(CONFIG_SFC_MTD)	+= mtd.o
 sfc-$(CONFIG_SFC_SRIOV)	+= sriov.o ef10_sriov.o ef100_sriov.o ef100_rep.o \
                            mae.o tc.o tc_bindings.o tc_counters.o \
-                           tc_encap_actions.o
+                           tc_encap_actions.o tc_conntrack.o
 
 obj-$(CONFIG_SFC)	+= sfc.o
 

drivers/net/ethernet/sfc/tc.c

···
 #include "tc.h"
 #include "tc_bindings.h"
 #include "tc_encap_actions.h"
+#include "tc_conntrack.h"
 #include "mae.h"
 #include "ef100_rep.h"
 #include "efx.h"
···
 	rc = rhashtable_init(&efx->tc->match_action_ht, &efx_tc_match_action_ht_params);
 	if (rc < 0)
 		goto fail_match_action_ht;
+	rc = efx_tc_init_conntrack(efx);
+	if (rc < 0)
+		goto fail_conntrack;
 	efx->tc->reps_filter_uc = -1;
 	efx->tc->reps_filter_mc = -1;
 	INIT_LIST_HEAD(&efx->tc->dflt.pf.acts.list);
···
 	efx->tc->facts.reps.fw_id = MC_CMD_MAE_ACTION_SET_ALLOC_OUT_ACTION_SET_ID_NULL;
 	efx->extra_channel_type[EFX_EXTRA_CHANNEL_TC] = &efx_tc_channel_type;
 	return 0;
+fail_conntrack:
+	rhashtable_destroy(&efx->tc->match_action_ht);
 fail_match_action_ht:
 	rhashtable_destroy(&efx->tc->encap_match_ht);
 fail_encap_match_ht:
···
 				    efx);
 	rhashtable_free_and_destroy(&efx->tc->encap_match_ht,
 				    efx_tc_encap_match_free, NULL);
+	efx_tc_fini_conntrack(efx);
 	efx_tc_fini_counters(efx);
 	efx_tc_fini_encap_actions(efx);
 	mutex_unlock(&efx->tc->mutex);

drivers/net/ethernet/sfc/tc.h

···
  * @encap_ht: Hashtable of TC encap actions
  * @encap_match_ht: Hashtable of TC encap matches
  * @match_action_ht: Hashtable of TC match-action rules
+ * @ct_zone_ht: Hashtable of TC conntrack flowtable bindings
  * @neigh_ht: Hashtable of neighbour watches (&struct efx_neigh_binder)
  * @meta_ct: MAE table layout for conntrack table
  * @reps_mport_id: MAE port allocated for representor RX
···
 	struct rhashtable encap_ht;
 	struct rhashtable encap_match_ht;
 	struct rhashtable match_action_ht;
+	struct rhashtable ct_zone_ht;
 	struct rhashtable neigh_ht;
 	struct efx_tc_table_ct meta_ct;
 	u32 reps_mport_id, reps_mport_vport_id;

drivers/net/ethernet/sfc/tc_conntrack.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/****************************************************************************
+ * Driver for Solarflare network controllers and boards
+ * Copyright 2023, Advanced Micro Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation, incorporated herein by reference.
+ */
+
+#include "tc_conntrack.h"
+#include "tc.h"
+#include "mae.h"
+
+static int efx_tc_flow_block(enum tc_setup_type type, void *type_data,
+			     void *cb_priv);
+
+static const struct rhashtable_params efx_tc_ct_zone_ht_params = {
+	.key_len	= offsetof(struct efx_tc_ct_zone, linkage),
+	.key_offset	= 0,
+	.head_offset	= offsetof(struct efx_tc_ct_zone, linkage),
+};
+
+static void efx_tc_ct_zone_free(void *ptr, void *arg)
+{
+	struct efx_tc_ct_zone *zone = ptr;
+	struct efx_nic *efx = zone->efx;
+
+	netif_err(efx, drv, efx->net_dev,
+		  "tc ct_zone %u still present at teardown, removing\n",
+		  zone->zone);
+
+	nf_flow_table_offload_del_cb(zone->nf_ft, efx_tc_flow_block, zone);
+	kfree(zone);
+}
+
+int efx_tc_init_conntrack(struct efx_nic *efx)
+{
+	int rc;
+
+	rc = rhashtable_init(&efx->tc->ct_zone_ht, &efx_tc_ct_zone_ht_params);
+	if (rc < 0)
+		return rc;
+	return 0;
+}
+
+void efx_tc_fini_conntrack(struct efx_nic *efx)
+{
+	rhashtable_free_and_destroy(&efx->tc->ct_zone_ht, efx_tc_ct_zone_free, NULL);
+}
+
+static int efx_tc_flow_block(enum tc_setup_type type, void *type_data,
+			     void *cb_priv)
+{
+	return -EOPNOTSUPP;
+}
+
+struct efx_tc_ct_zone *efx_tc_ct_register_zone(struct efx_nic *efx, u16 zone,
+					       struct nf_flowtable *ct_ft)
+{
+	struct efx_tc_ct_zone *ct_zone, *old;
+	int rc;
+
+	ct_zone = kzalloc(sizeof(*ct_zone), GFP_USER);
+	if (!ct_zone)
+		return ERR_PTR(-ENOMEM);
+	ct_zone->zone = zone;
+	old = rhashtable_lookup_get_insert_fast(&efx->tc->ct_zone_ht,
+						&ct_zone->linkage,
+						efx_tc_ct_zone_ht_params);
+	if (old) {
+		/* don't need our new entry */
+		kfree(ct_zone);
+		if (!refcount_inc_not_zero(&old->ref))
+			return ERR_PTR(-EAGAIN);
+		/* existing entry found */
+		WARN_ON_ONCE(old->nf_ft != ct_ft);
+		netif_dbg(efx, drv, efx->net_dev,
+			  "Found existing ct_zone for %u\n", zone);
+		return old;
+	}
+	ct_zone->nf_ft = ct_ft;
+	ct_zone->efx = efx;
+	rc = nf_flow_table_offload_add_cb(ct_ft, efx_tc_flow_block, ct_zone);
+	netif_dbg(efx, drv, efx->net_dev, "Adding new ct_zone for %u, rc %d\n",
+		  zone, rc);
+	if (rc < 0)
+		goto fail;
+	refcount_set(&ct_zone->ref, 1);
+	return ct_zone;
+fail:
+	rhashtable_remove_fast(&efx->tc->ct_zone_ht, &ct_zone->linkage,
+			       efx_tc_ct_zone_ht_params);
+	kfree(ct_zone);
+	return ERR_PTR(rc);
+}
+
+void efx_tc_ct_unregister_zone(struct efx_nic *efx,
+			       struct efx_tc_ct_zone *ct_zone)
+{
+	if (!refcount_dec_and_test(&ct_zone->ref))
+		return; /* still in use */
+	nf_flow_table_offload_del_cb(ct_zone->nf_ft, efx_tc_flow_block, ct_zone);
+	rhashtable_remove_fast(&efx->tc->ct_zone_ht, &ct_zone->linkage,
+			       efx_tc_ct_zone_ht_params);
+	netif_dbg(efx, drv, efx->net_dev, "Removed ct_zone for %u\n",
+		  ct_zone->zone);
+	kfree(ct_zone);
+}

drivers/net/ethernet/sfc/tc_conntrack.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/****************************************************************************
+ * Driver for Solarflare network controllers and boards
+ * Copyright 2023, Advanced Micro Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation, incorporated herein by reference.
+ */
+
+#ifndef EFX_TC_CONNTRACK_H
+#define EFX_TC_CONNTRACK_H
+#include "net_driver.h"
+
+#if IS_ENABLED(CONFIG_SFC_SRIOV)
+#include <linux/refcount.h>
+#include <net/netfilter/nf_flow_table.h>
+
+struct efx_tc_ct_zone {
+	u16 zone;
+	struct rhash_head linkage;
+	refcount_t ref;
+	struct nf_flowtable *nf_ft;
+	struct efx_nic *efx;
+};
+
+/* create/teardown hashtables */
+int efx_tc_init_conntrack(struct efx_nic *efx);
+void efx_tc_fini_conntrack(struct efx_nic *efx);
+
+struct efx_tc_ct_zone *efx_tc_ct_register_zone(struct efx_nic *efx, u16 zone,
+					       struct nf_flowtable *ct_ft);
+void efx_tc_ct_unregister_zone(struct efx_nic *efx,
+			       struct efx_tc_ct_zone *ct_zone);
+
+#endif /* CONFIG_SFC_SRIOV */
+#endif /* EFX_TC_CONNTRACK_H */