// $Id: Intercept.nc,v 1.1.10.4 2003/08/26 09:08:12 cssharp Exp $/*									tab:4 * "Copyright (c) 2000-2003 The Regents of the University  of California.   * All rights reserved. * * Permission to use, copy, modify, and distribute this software and its * documentation for any purpose, without fee, and without written agreement is * hereby granted, provided that the above copyright notice, the following * two paragraphs and the author appear in all copies of this software. *  * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *  * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS." * * Copyright (c) 2002-2003 Intel Corporation * All rights reserved. * * This file is distributed under the terms in the attached INTEL-LICENSE      * file. If you do not find these files, copies can be found by writing to * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA,  * 94704.  Attention:  Intel License Inquiry. *//* * Authors:		Philip Levis * Date last modified:  1/30/03 * * The Intercept interface should be provided by all protocols above layer * 2 (GenericComm/AM). For example, ad-hoc routing protocols should * provide this interface for in-network packet processing. * * The goal of this interface is to allow transmission hops to  * process packet payloads without having to know about the internal * structure of the packet or the layers below them in the stack. * * The Interface interface is only used by nodes that are forwarding a * multihop messages. A protocol layer does not perform a buffer swap, but * can tell lower layers to not forward a packet by giving a FAIL return value. * Using this, an in-network intermediary can receive multiple packets, aggregate * their results, then forward them on to the destination. * * For example, if a packet takes the route A->B->C->D * * A: send(); * B: intercept(); * C: intercept(); * D: receive(); *//** * @author Philip Levis */includes AM;interface Intercept {  /**   *   * Signals that a message has been received, which is supposed to be   * forwarded to another destination. Allows protocol layers above the   * routing layer to perform data aggregation or make application-specific   * decisions on whether to forward.   *   * @param msg The complete buffer received.   *   * @param payload The payload portion of the packet for this   * protocol layer. If this layer has layers above it, it should signal   * receive() with payload incremented by the size of its header. Payload   * is a pointer into the msg structure.   *   * @param payloadLen The length of the payload buffer. If this layer   * has layers above it, it should signal receive() with payloadLen   * decreased by the size of its headers and footers.   *   * @return SUCCESS indicates the packet should be forwarded, FAIL   * indicates that it should not be forwarded.   *   */  event result_t intercept(TOS_MsgPtr msg, void* payload, uint16_t payloadLen);  }