bpf: nodeport: handle result from encap ctx_redirect() in revDNAT path

When redirecting a packet into the tunnel, return the result of that
operation. Right now we're not reporting potential errors from the helper
call.

This will become more relevant with native XDP encapsulation, where
ctx_redirect() can also turn the CTX_REDIRECT into a XDP_TX.

Fixes: ff44164 ("bpf: Align rev_nodeport_lb{4,6} wrt egress GW tunnel mode")
Signed-off-by: Julian Wiedmann <jwi@isovalent.com>

bpf/lib/nodeport.h

@@ -1218,7 +1218,7 @@ static __always_inline int rev_nodeport_lb6(struct __ctx_buff *ctx, __s8 *ext_er
 	ret = __encap_with_nodeid(ctx, tunnel_endpoint, SECLABEL, dst_id,
 				  NOT_VTEP_DST, reason, monitor, &ifindex);
 	if (ret == CTX_ACT_REDIRECT)
-		ctx_redirect(ctx, ifindex, 0);
+		ret = ctx_redirect(ctx, ifindex, 0);
 	return ret;
 #endif
 }
@@ -2444,7 +2444,7 @@ static __always_inline int rev_nodeport_lb4(struct __ctx_buff *ctx, __s8 *ext_er
 	ret = __encap_with_nodeid(ctx, tunnel_endpoint, SECLABEL, dst_id,
 				  NOT_VTEP_DST, reason, monitor, &ifindex);
 	if (ret == CTX_ACT_REDIRECT)
-		ctx_redirect(ctx, ifindex, 0);
+		ret = ctx_redirect(ctx, ifindex, 0);
 	return ret;
 #endif
 }