Source: network-nack.js

  1. /**
  2.  * Copyright (C) 2016-2018 Regents of the University of California.
  3.  * @author: Jeff Thompson <jefft0@remap.ucla.edu>
  4.  * @author: From ndn-cxx nack.hpp https://github.com/named-data/ndn-cxx/blob/master/src/lp/nack.hpp
  5.  *
  6.  * This program is free software: you can redistribute it and/or modify
  7.  * it under the terms of the GNU Lesser General Public License as published by
  8.  * the Free Software Foundation, either version 3 of the License, or
  9.  * (at your option) any later version.
  10.  *
  11.  * This program is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14.  * GNU Lesser General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU Lesser General Public License
  17.  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18.  * A copy of the GNU Lesser General Public License is in the file COPYING.
  19.  */
  21. /**
  22.  * NetworkNack represents a network Nack packet and includes a Nack reason.
  23.  * @constructor
  24.  */
  25. var NetworkNack = function NetworkNack()
  26. {
  27.   this.reason_ = NetworkNack.Reason.NONE;
  28.   this.otherReasonCode_ = -1;
  29. };
  31. exports.NetworkNack = NetworkNack;
  33. /**
  34.  * A NetworkNack.Reason specifies the reason in a NetworkNack packet. If the
  35.  * reason code in the packet is not a recognized enum value, then we use
  36.  * Reason.OTHER_CODE and you can call getOtherReasonCode(). We do this to keep
  37.  * the recognized reason values independent of packet encoding formats.
  38.  */
  39. NetworkNack.Reason = {
  40.   NONE:         0,
  41.   CONGESTION:  50,
  42.   DUPLICATE:  100,
  43.   NO_ROUTE:   150,
  44.   OTHER_CODE: 0x7fff
  45. };
  47. /**
  48.  * Get the network Nack reason.
  49.  * @return {number} The reason enum value from NetworkNack.Reason. If this is
  50.  * Reason.OTHER_CODE, then call getOtherReasonCode() to get the unrecognized
  51.  * reason code.
  52.  */
  53. NetworkNack.prototype.getReason = function() { return this.reason_; };
  55. /**
  56.  * Get the reason code from the packet which is other than a recognized
  57.  * Reason enum value. This is only meaningful if getReason() is
  58.  * Reason.OTHER_CODE.
  59.  * @return {number} The reason code.
  60.  */
  61. NetworkNack.prototype.getOtherReasonCode = function()
  62. {
  63.   return this.otherReasonCode_;
  64. };
  66. /**
  67.  * Set the network Nack reason.
  68.  * @param {number} reason The network Nack reason enum value from
  69.  * NetworkNack.Reason. If the packet's reason code is not a recognized Reason
  70.  * enum value, use Reason.OTHER_CODE and call setOtherReasonCode().
  71.  */
  72. NetworkNack.prototype.setReason = function(reason) { this.reason_ = reason; };
  74. /**
  75.  * Set the packet's reason code to use when the reason enum is
  76.  * Reason.OTHER_CODE. If the packet's reason code is a recognized enum value,
  77.  * just call setReason().
  78.  * @param {number} otherReasonCode The packet's unrecognized reason code, which
  79.  * must be non-negative.
  80.  */
  81. NetworkNack.prototype.setOtherReasonCode = function(otherReasonCode)
  82. {
  83.   if (otherReasonCode < 0)
  84.     throw new Error("NetworkNack other reason code must be non-negative");
  85.   this.otherReasonCode_ = otherReasonCode;
  86. };
  88. /**
  89.  * Get the first header field in lpPacket which is a NetworkNack. This is
  90.  * an internal method which the application normally would not use.
  91.  * @param {LpPacket} lpPacket The LpPacket with the header fields to search.
  92.  * @return {NetworkNack} The first NetworkNack header field, or null if not
  93.  * found.
  94.  */
  95. NetworkNack.getFirstHeader = function(lpPacket)
  96. {
  97.   for (var i = 0; i < lpPacket.countHeaderFields(); ++i) {
  98.     var field = lpPacket.getHeaderField(i);
  99.     if (field instanceof NetworkNack)
  100.       return field;
  101.   }
  103.   return null;
  104. };