nfp: flower: push vlan after tunnel in merge

NFP allows the merging of 2 flows together into a single offloaded flow.
In the kernel datapath the packet must match 1 flow, impliment its
actions, recirculate, match the 2nd flow and also impliment its actions.
Merging creates a single flow with all actions from the 2 original flows.

Firmware impliments a tunnel header push as the packet is about to egress
the card. Therefore, if the first merge rule candiate pushes a tunnel,
then the second rule can only have an egress action for a valid merge to
occur (or else the action ordering will be incorrect). This prevents the
pushing of a tunnel header followed by the pushing of a vlan header.

In order to support this behaviour, firmware allows VLAN information to
be encoded in the tunnel push action. If this is non zero then the fw will
push a VLAN after the tunnel header push meaning that 2 such flows with
these actions can be merged (with action order being maintained).

Support tunnel in VLAN pushes by encoding VLAN information in the tunnel
push action of any merge flow requiring this.
Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -220,7 +220,8 @@ struct nfp_fl_set_ipv4_tun {
 	__be16 tun_flags;
 	u8 ttl;
 	u8 tos;
-	__be32 extra;
+	__be16 outer_vlan_tpid;
+	__be16 outer_vlan_tci;
 	u8 tun_len;
 	u8 res2;
 	__be16 tun_proto;

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

@@ -732,20 +732,53 @@ nfp_flower_copy_pre_actions(char *act_dst, char *act_src, int len,
 	return act_off;
 }
 
-static int nfp_fl_verify_post_tun_acts(char *acts, int len)
+static int
+nfp_fl_verify_post_tun_acts(char *acts, int len, struct nfp_fl_push_vlan **vlan)
 {
 	struct nfp_fl_act_head *a;
 	unsigned int act_off = 0;
 
 	while (act_off < len) {
 		a = (struct nfp_fl_act_head *)&acts[act_off];
-		if (a->jump_id != NFP_FL_ACTION_OPCODE_OUTPUT)
+
+		if (a->jump_id == NFP_FL_ACTION_OPCODE_PUSH_VLAN && !act_off)
+			*vlan = (struct nfp_fl_push_vlan *)a;
+		else if (a->jump_id != NFP_FL_ACTION_OPCODE_OUTPUT)
 			return -EOPNOTSUPP;
 
 		act_off += a->len_lw << NFP_FL_LW_SIZ;
 	}
 
+	/* Ensure any VLAN push also has an egress action. */
+	if (*vlan && act_off <= sizeof(struct nfp_fl_push_vlan))
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static int
+nfp_fl_push_vlan_after_tun(char *acts, int len, struct nfp_fl_push_vlan *vlan)
+{
+	struct nfp_fl_set_ipv4_tun *tun;
+	struct nfp_fl_act_head *a;
+	unsigned int act_off = 0;
+
+	while (act_off < len) {
+		a = (struct nfp_fl_act_head *)&acts[act_off];
+
+		if (a->jump_id == NFP_FL_ACTION_OPCODE_SET_IPV4_TUNNEL) {
+			tun = (struct nfp_fl_set_ipv4_tun *)a;
+			tun->outer_vlan_tpid = vlan->vlan_tpid;
+			tun->outer_vlan_tci = vlan->vlan_tci;
+
 			return 0;
+		}
+
+		act_off += a->len_lw << NFP_FL_LW_SIZ;
+	}
+
+	/* Return error if no tunnel action is found. */
+	return -EOPNOTSUPP;
 }
 
 static int
@@ -754,6 +787,7 @@ nfp_flower_merge_action(struct nfp_fl_payload *sub_flow1,
 			struct nfp_fl_payload *merge_flow)
 {
 	unsigned int sub1_act_len, sub2_act_len, pre_off1, pre_off2;
+	struct nfp_fl_push_vlan *post_tun_push_vlan = NULL;
 	bool tunnel_act = false;
 	char *merge_act;
 	int err;
@@ -790,18 +824,36 @@ nfp_flower_merge_action(struct nfp_fl_payload *sub_flow1,
 	sub2_act_len -= pre_off2;
 
 	/* FW does a tunnel push when egressing, therefore, if sub_flow 1 pushes
-	 * a tunnel, sub_flow 2 can only have output actions for a valid merge.
+	 * a tunnel, there are restrictions on what sub_flow 2 actions lead to a
+	 * valid merge.
 	 */
 	if (tunnel_act) {
 		char *post_tun_acts = &sub_flow2->action_data[pre_off2];
 
-		err = nfp_fl_verify_post_tun_acts(post_tun_acts, sub2_act_len);
+		err = nfp_fl_verify_post_tun_acts(post_tun_acts, sub2_act_len,
+						  &post_tun_push_vlan);
 		if (err)
 			return err;
+
+		if (post_tun_push_vlan) {
+			pre_off2 += sizeof(*post_tun_push_vlan);
+			sub2_act_len -= sizeof(*post_tun_push_vlan);
+		}
 	}
 
 	/* Copy remaining actions from sub_flows 1 and 2. */
 	memcpy(merge_act, sub_flow1->action_data + pre_off1, sub1_act_len);
+
+	if (post_tun_push_vlan) {
+		/* Update tunnel action in merge to include VLAN push. */
+		err = nfp_fl_push_vlan_after_tun(merge_act, sub1_act_len,
+						 post_tun_push_vlan);
+		if (err)
+			return err;
+
+		merge_flow->meta.act_len -= sizeof(*post_tun_push_vlan);
+	}
+
 	merge_act += sub1_act_len;
 	memcpy(merge_act, sub_flow2->action_data + pre_off2, sub2_act_len);