nfp: flower: support hw offload for ct nat action

support ct nat action when pre_ct merge with post_ct
and nft. at the same time, add the extra checksum action
and hardware stats for nft to meet the action check when
do nat.
Signed-off-by: Hui Zhou <hui.zhou@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/netronome/nfp/flower/conntrack.c

 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 /* Copyright (C) 2021 Corigine, Inc. */
 
+#include <net/tc_act/tc_csum.h>
+#include <net/tc_act/tc_ct.h>
+
 #include "conntrack.h"
 #include "../nfp_port.h"
 
@@ -56,9 +59,17 @@ bool is_pre_ct_flow(struct flow_cls_offload *flow)
 	int i;
 
 	flow_action_for_each(i, act, &flow->rule->action) {
-		if (act->id == FLOW_ACTION_CT && !act->ct.action)
-			return true;
+		if (act->id == FLOW_ACTION_CT) {
+			/* The pre_ct rule only have the ct or ct nat action, cannot
+			 * contains other ct action e.g ct commit and so on.
+			 */
+			if ((!act->ct.action || act->ct.action == TCA_CT_ACT_NAT))
+				return true;
+			else
+				return false;
+		}
 	}
+
 	return false;
 }
 
@@ -66,13 +77,37 @@ bool is_post_ct_flow(struct flow_cls_offload *flow)
 {
 	struct flow_rule *rule = flow_cls_offload_flow_rule(flow);
 	struct flow_dissector *dissector = rule->match.dissector;
+	struct flow_action_entry *act;
+	bool exist_ct_clear = false;
 	struct flow_match_ct ct;
+	int i;
+
+	/* post ct entry cannot contains any ct action except ct_clear. */
+	flow_action_for_each(i, act, &flow->rule->action) {
+		if (act->id == FLOW_ACTION_CT) {
+			/* ignore ct clear action. */
+			if (act->ct.action == TCA_CT_ACT_CLEAR) {
+				exist_ct_clear = true;
+				continue;
+			}
+
+			return false;
+		}
+	}
 
 	if (dissector->used_keys & BIT(FLOW_DISSECTOR_KEY_CT)) {
 		flow_rule_match_ct(rule, &ct);
 		if (ct.key->ct_state & TCA_FLOWER_KEY_CT_FLAGS_ESTABLISHED)
 			return true;
+	} else {
+		/* when do nat with ct, the post ct entry ignore the ct status,
+		 * will match the nat field(sip/dip) instead. In this situation,
+		 * the flow chain index is not zero and contains ct clear action.
+		 */
+		if (flow->common.chain_index && exist_ct_clear)
+			return true;
 	}
+
 	return false;
 }
 
@@ -168,6 +203,20 @@ static void *get_mangled_tos_ttl(struct flow_rule *rule, void *buf,
 	return buf;
 }
 
+/* Note entry1 and entry2 are not swappable. only skip ip and
+ * tport merge check for pre_ct and post_ct when pre_ct do nat.
+ */
+static bool nfp_ct_merge_check_cannot_skip(struct nfp_fl_ct_flow_entry *entry1,
+					   struct nfp_fl_ct_flow_entry *entry2)
+{
+	/* only pre_ct have NFP_FL_ACTION_DO_NAT flag. */
+	if ((entry1->flags & NFP_FL_ACTION_DO_NAT) &&
+	    entry2->type == CT_TYPE_POST_CT)
+		return false;
+
+	return true;
+}
+
 /* Note entry1 and entry2 are not swappable, entry1 should be
  * the former flow whose mangle action need be taken into account
  * if existed, and entry2 should be the latter flow whose action
@@ -225,7 +274,12 @@ static int nfp_ct_merge_check(struct nfp_fl_ct_flow_entry *entry1,
 			goto check_failed;
 	}
 
-	if (ovlp_keys & BIT(FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
+	/* if pre ct entry do nat, the nat ip exists in nft entry,
+	 * will be do merge check when do nft and post ct merge,
+	 * so skip this ip merge check here.
+	 */
+	if ((ovlp_keys & BIT(FLOW_DISSECTOR_KEY_IPV4_ADDRS)) &&
+	    nfp_ct_merge_check_cannot_skip(entry1, entry2)) {
 		struct flow_match_ipv4_addrs match1, match2;
 
 		flow_rule_match_ipv4_addrs(entry1->rule, &match1);
@@ -242,7 +296,12 @@ static int nfp_ct_merge_check(struct nfp_fl_ct_flow_entry *entry1,
 			goto check_failed;
 	}
 
-	if (ovlp_keys & BIT(FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
+	/* if pre ct entry do nat, the nat ip exists in nft entry,
+	 * will be do merge check when do nft and post ct merge,
+	 * so skip this ip merge check here.
+	 */
+	if ((ovlp_keys & BIT(FLOW_DISSECTOR_KEY_IPV6_ADDRS)) &&
+	    nfp_ct_merge_check_cannot_skip(entry1, entry2)) {
 		struct flow_match_ipv6_addrs match1, match2;
 
 		flow_rule_match_ipv6_addrs(entry1->rule, &match1);
@@ -259,7 +318,12 @@ static int nfp_ct_merge_check(struct nfp_fl_ct_flow_entry *entry1,
 			goto check_failed;
 	}
 
-	if (ovlp_keys & BIT(FLOW_DISSECTOR_KEY_PORTS)) {
+	/* if pre ct entry do nat, the nat tport exists in nft entry,
+	 * will be do merge check when do nft and post ct merge,
+	 * so skip this tport merge check here.
+	 */
+	if ((ovlp_keys & BIT(FLOW_DISSECTOR_KEY_PORTS)) &&
+	    nfp_ct_merge_check_cannot_skip(entry1, entry2)) {
 		enum flow_action_mangle_base htype = FLOW_ACT_MANGLE_UNSPEC;
 		struct flow_match_ports match1, match2;
 
@@ -468,6 +532,12 @@ static int nfp_ct_check_meta(struct nfp_fl_ct_flow_entry *post_ct_entry,
 			return -EINVAL;
 
 		return 0;
+	} else {
+		/* post_ct with ct clear action will not match the
+		 * ct status when nft is nat entry.
+		 */
+		if (nft_entry->flags & NFP_FL_ACTION_DO_MANGLE)
+			return 0;
 	}
 
 	return -EINVAL;
@@ -537,11 +607,37 @@ nfp_fl_calc_key_layers_sz(struct nfp_fl_key_ls in_key_ls, uint16_t *map)
 	return key_size;
 }
 
+/* get the csum flag according the ip proto and mangle action. */
+static void nfp_fl_get_csum_flag(struct flow_action_entry *a_in, u8 ip_proto, u32 *csum)
+{
+	if (a_in->id != FLOW_ACTION_MANGLE)
+		return;
+
+	switch (a_in->mangle.htype) {
+	case FLOW_ACT_MANGLE_HDR_TYPE_IP4:
+		*csum |= TCA_CSUM_UPDATE_FLAG_IPV4HDR;
+		if (ip_proto == IPPROTO_TCP)
+			*csum |= TCA_CSUM_UPDATE_FLAG_TCP;
+		else if (ip_proto == IPPROTO_UDP)
+			*csum |= TCA_CSUM_UPDATE_FLAG_UDP;
+		break;
+	case FLOW_ACT_MANGLE_HDR_TYPE_TCP:
+		*csum |= TCA_CSUM_UPDATE_FLAG_TCP;
+		break;
+	case FLOW_ACT_MANGLE_HDR_TYPE_UDP:
+		*csum |= TCA_CSUM_UPDATE_FLAG_UDP;
+		break;
+	default:
+		break;
+	}
+}
+
 static int nfp_fl_merge_actions_offload(struct flow_rule **rules,
 					struct nfp_flower_priv *priv,
 					struct net_device *netdev,
 					struct nfp_fl_payload *flow_pay)
 {
+	enum flow_action_hw_stats tmp_stats = FLOW_ACTION_HW_STATS_DONT_CARE;
 	struct flow_action_entry *a_in;
 	int i, j, num_actions, id;
 	struct flow_rule *a_rule;
@@ -551,15 +647,25 @@ static int nfp_fl_merge_actions_offload(struct flow_rule **rules,
 		      rules[CT_TYPE_NFT]->action.num_entries +
 		      rules[CT_TYPE_POST_CT]->action.num_entries;
 
-	a_rule = flow_rule_alloc(num_actions);
+	/* Add one action to make sure there is enough room to add an checksum action
+	 * when do nat.
+	 */
+	a_rule = flow_rule_alloc(num_actions + 1);
 	if (!a_rule)
 		return -ENOMEM;
 
 	/* Actions need a BASIC dissector. */
 	a_rule->match = rules[CT_TYPE_PRE_CT]->match;
+	/* post_ct entry have one action at least. */
+	if (rules[CT_TYPE_POST_CT]->action.num_entries != 0) {
+		tmp_stats = rules[CT_TYPE_POST_CT]->action.entries[0].hw_stats;
+	}
 
 	/* Copy actions */
 	for (j = 0; j < _CT_TYPE_MAX; j++) {
+		u32 csum_updated = 0;
+		u8 ip_proto = 0;
+
 		if (flow_rule_match_key(rules[j], FLOW_DISSECTOR_KEY_BASIC)) {
 			struct flow_match_basic match;
 
@@ -571,8 +677,10 @@ static int nfp_fl_merge_actions_offload(struct flow_rule **rules,
 			 * through the subflows and assign the proper subflow to a_rule
 			 */
 			flow_rule_match_basic(rules[j], &match);
-			if (match.mask->ip_proto)
+			if (match.mask->ip_proto) {
 				a_rule->match = rules[j]->match;
+				ip_proto = match.key->ip_proto;
+			}
 		}
 
 		for (i = 0; i < rules[j]->action.num_entries; i++) {
@@ -589,11 +697,32 @@ static int nfp_fl_merge_actions_offload(struct flow_rule **rules,
 			case FLOW_ACTION_CT_METADATA:
 				continue;
 			default:
+				/* nft entry is generated by tc ct, which mangle action do not care
+				 * the stats, inherit the post entry stats to meet the
+				 * flow_action_hw_stats_check.
+				 */
+				if (j == CT_TYPE_NFT) {
+					if (a_in->hw_stats == FLOW_ACTION_HW_STATS_DONT_CARE)
+						a_in->hw_stats = tmp_stats;
+					nfp_fl_get_csum_flag(a_in, ip_proto, &csum_updated);
+				}
 				memcpy(&a_rule->action.entries[offset++],
 				       a_in, sizeof(struct flow_action_entry));
 				break;
 			}
 		}
+		/* nft entry have mangle action, but do not have checksum action when do NAT,
+		 * hardware will automatically fix IPv4 and TCP/UDP checksum. so add an csum action
+		 * to meet csum action check.
+		 */
+		if (csum_updated) {
+			struct flow_action_entry *csum_action;
+
+			csum_action = &a_rule->action.entries[offset++];
+			csum_action->id = FLOW_ACTION_CSUM;
+			csum_action->csum_flags = csum_updated;
+			csum_action->hw_stats = tmp_stats;
+		}
 	}
 
 	/* Some actions would have been ignored, so update the num_entries field */
@@ -1191,6 +1320,49 @@ static struct net_device *get_netdev_from_rule(struct flow_rule *rule)
 	return NULL;
 }
 
+static void nfp_nft_ct_translate_mangle_action(struct flow_action_entry *mangle_action)
+{
+	if (mangle_action->id != FLOW_ACTION_MANGLE)
+		return;
+
+	switch (mangle_action->mangle.htype) {
+	case FLOW_ACT_MANGLE_HDR_TYPE_IP4:
+	case FLOW_ACT_MANGLE_HDR_TYPE_IP6:
+		mangle_action->mangle.val = (__force u32)cpu_to_be32(mangle_action->mangle.val);
+		mangle_action->mangle.mask = (__force u32)cpu_to_be32(mangle_action->mangle.mask);
+		return;
+
+	case FLOW_ACT_MANGLE_HDR_TYPE_TCP:
+	case FLOW_ACT_MANGLE_HDR_TYPE_UDP:
+		mangle_action->mangle.val = (__force u16)cpu_to_be16(mangle_action->mangle.val);
+		mangle_action->mangle.mask = (__force u16)cpu_to_be16(mangle_action->mangle.mask);
+		return;
+
+	default:
+		return;
+	}
+}
+
+static int nfp_nft_ct_set_flow_flag(struct flow_action_entry *act,
+				    struct nfp_fl_ct_flow_entry *entry)
+{
+	switch (act->id) {
+	case FLOW_ACTION_CT:
+		if (act->ct.action == TCA_CT_ACT_NAT)
+			entry->flags |= NFP_FL_ACTION_DO_NAT;
+		break;
+
+	case FLOW_ACTION_MANGLE:
+		entry->flags |= NFP_FL_ACTION_DO_MANGLE;
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
 static struct
 nfp_fl_ct_flow_entry *nfp_fl_ct_add_flow(struct nfp_fl_ct_zone_entry *zt,
 					 struct net_device *netdev,
@@ -1257,6 +1429,13 @@ nfp_fl_ct_flow_entry *nfp_fl_ct_add_flow(struct nfp_fl_ct_zone_entry *zt,
 
 		new_act = &entry->rule->action.entries[i];
 		memcpy(new_act, act, sizeof(struct flow_action_entry));
+		/* nft entry mangle field is host byte order, need translate to
+		 * network byte order.
+		 */
+		if (is_nft)
+			nfp_nft_ct_translate_mangle_action(new_act);
+
+		nfp_nft_ct_set_flow_flag(new_act, entry);
 		/* Entunnel is a special case, need to allocate and copy
 		 * tunnel info.
 		 */

drivers/net/ethernet/netronome/nfp/flower/conntrack.h

@@ -103,6 +103,10 @@ enum nfp_nfp_layer_name {
 	_FLOW_PAY_LAYERS_MAX
 };
 
+/* NFP flow entry flags. */
+#define NFP_FL_ACTION_DO_NAT		BIT(0)
+#define NFP_FL_ACTION_DO_MANGLE		BIT(1)
+
 /**
  * struct nfp_fl_ct_flow_entry - Flow entry containing conntrack flow information
  * @cookie:	Flow cookie, same as original TC flow, used as key
@@ -115,6 +119,7 @@ enum nfp_nfp_layer_name {
  * @rule:	Reference to the original TC flow rule
  * @stats:	Used to cache stats for updating
  * @tun_offset: Used to indicate tunnel action offset in action list
+ * @flags:	Used to indicate flow flag like NAT which used by merge.
  */
 struct nfp_fl_ct_flow_entry {
 	unsigned long cookie;
@@ -127,6 +132,7 @@ struct nfp_fl_ct_flow_entry {
 	struct flow_rule *rule;
 	struct flow_stats stats;
 	u8 tun_offset;		// Set to NFP_FL_CT_NO_TUN if no tun
+	u8 flags;
 };
 
 /**