nfp: bpf: add support for legacy redirect action

Data path has redirect support so expressing redirect
to the port frame came from is a trivial matter of
setting the right result code.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_bpf.h

@@ -60,6 +60,7 @@ enum static_regs {
 
 enum nfp_bpf_action_type {
 	NN_ACT_TC_DROP,
+	NN_ACT_TC_REDIR,
 };
 
 /* Software register representation, hardware encoding in asm.h */

drivers/net/ethernet/netronome/nfp/nfp_bpf_jit.c

@@ -1440,6 +1440,7 @@ static void nfp_outro_tc_legacy(struct nfp_prog *nfp_prog)
 {
 	const u8 act2code[] = {
 		[NN_ACT_TC_DROP]  = 0x22,
+		[NN_ACT_TC_REDIR] = 0x24
 	};
 	/* Target for aborts */
 	nfp_prog->tgt_abort = nfp_prog_current_offset(nfp_prog);
@@ -1468,6 +1469,7 @@ static void nfp_outro(struct nfp_prog *nfp_prog)
 {
 	switch (nfp_prog->act) {
 	case NN_ACT_TC_DROP:
+	case NN_ACT_TC_REDIR:
 		nfp_outro_tc_legacy(nfp_prog);
 		break;
 	}

drivers/net/ethernet/netronome/nfp/nfp_net_offload.c

@@ -123,6 +123,10 @@ nfp_net_bpf_get_act(struct nfp_net *nn, struct tc_cls_bpf_offload *cls_bpf)
 	list_for_each_entry(a, &actions, list) {
 		if (is_tcf_gact_shot(a))
 			return NN_ACT_TC_DROP;
+
+		if (is_tcf_mirred_redirect(a) &&
+		    tcf_mirred_ifindex(a) == nn->netdev->ifindex)
+			return NN_ACT_TC_REDIR;
 	}
 
 	return -ENOTSUPP;