net: socket: Return 0 in recvfrom() if buffer size is 0

If user has buffer with size 0, then return 0.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

subsys/net/lib/sockets/sockets.c

@@ -802,6 +802,10 @@ ssize_t zsock_recvfrom_ctx(struct net_context *ctx, void *buf, size_t max_len,
 {
 	enum net_sock_type sock_type = net_context_get_type(ctx);
 
+	if (max_len == 0) {
+		return 0;
+	}
+
 	if (sock_type == SOCK_DGRAM) {
 		return zsock_recv_dgram(ctx, buf, max_len, flags, src_addr, addrlen);
 	} else if (sock_type == SOCK_STREAM) {