 announcing an ipaddr. Used to send announce messages for address conflict detection.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">netif</td><td>the lwip network interface on which to send the request </td></tr>
    <tr><td class="paramname">ipaddr</td><td>the IP address to announce </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>ERR_OK if the request has been sent ERR_MEM if the ARP packet couldn't be allocated any 