udp-protocol.cpp
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2014-2024, Regents of the University of California,
4  * Arizona Board of Regents,
5  * Colorado State University,
6  * University Pierre & Marie Curie, Sorbonne University,
7  * Washington University in St. Louis,
8  * Beijing Institute of Technology,
9  * The University of Memphis.
10  *
11  * This file is part of NFD (Named Data Networking Forwarding Daemon).
12  * See AUTHORS.md for complete list of NFD authors and contributors.
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25 
26 #include "udp-protocol.hpp"
27 
28 #include <limits>
29 
30 namespace nfd::udp {
31 
32 ssize_t
33 computeMtu(const Endpoint& localEndpoint)
34 {
35  size_t mtu = 0;
36  if (localEndpoint.address().is_v4()) { // IPv4
37  mtu = std::numeric_limits<uint16_t>::max(); // maximum Total Length
38  mtu -= sizeof(uint32_t) * ((1 << 4) - 1); // maximum Internet Header Length
39  }
40  else { // IPv6
41  mtu = std::numeric_limits<uint16_t>::max(); // maximum Payload Length
42  }
43  mtu -= sizeof(uint16_t) * 4; // size of UDP header
44  return mtu;
45 }
46 
47 } // namespace nfd::udp
ssize_t computeMtu(const Endpoint &localEndpoint)
Computes the maximum payload size in a UDP packet.
boost::asio::ip::udp::endpoint Endpoint