参考了网上几个 traceroute的实现版本，存在一些缺陷，比如没有做超时处理，或者只能在window下使用。自己用boost实现了一个traceroute小工具，在window下正常运行。

先来看下面实现的原理。这些说明来自维基百科。traceroute，现代Linux系统称为tracepath， Windows 系统称为tracert，是一种电脑网络工具。它可显示 数据包 在IP网络经过的路由器的 IP地址。 程序利用增加存活时间（TTL）值来实现其功能的。每当数据包经过一个路由器，其存活时间就会减1。当其存活时间是0时，主机便取消数据包，并传送一个 ICMP TTL数据包给原数据包的发出者。

下面是具体实现的源代码：

  1 //
  2 // traceroute.cpp
  3 // ~~~~~~~~
  4 //
  5 // BoSheng Lu 2013-04-25
  6 //
  7 // Version 1.0.
  8 //
 10 #include <boost/asio.hpp>
 11 #include <boost/bind.hpp>
 12 #include<boost/thread.hpp>
 13 #include <istream>
 14 #include <iostream>
 15 #include<iomanip>
 16 #include<string> 
 17 #include <ostream>
 19 #include "icmp_header.hpp"
 20 #include "ipv4_header.hpp"
 22 using boost::asio::ip::icmp;
 23 using boost::asio::deadline_timer;
 24 namespace posix_time = boost::posix_time;
 26 class traceroute
 27 {
 28 public:
 29     traceroute(boost::asio::io_service& io_service, const char* destination)
 30         : resolver_(io_service), socket_(io_service, icmp::v4()),
 31         sequence_number_(0), max_hop_(30)
 32     {
 33         icmp::resolver::query query(icmp::v4(), destination, "");
 34         destination_ = *resolver_.resolve(query);
 36         std::cout << "\nTracing route to " << destination 
 37         << " [" << destination_.address().to_string() << "]"
 38         << " with a maximum of " << max_hop_ << " hops.\n" << std::endl;
 40 #if defined(BOOST_WINDOWS)
 41         int timeout = 5000;
 42         if( setsockopt(socket_.native(), SOL_SOCKET, SO_RCVTIMEO, 
 43             (const char*)&timeout, sizeof(timeout)))
 44         {
 45              std::cout << "RCVTIMEO not set properly." << std::endl;
 46             throw std::runtime_error("RCVTIMEO not set properly");
 47         }
 48 #else
 49         struct timeval tv;
 50         tv.tv_sec  = 5; 
 51         tv.tv_usec = 0;         
 52         if( setsockopt(socket_.native(), SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
 53         {
 54             std::cout << "RCVTIMEO not set properly." << std::endl;
 55             throw std::runtime_error("RCVTIMEO not set properly");
 56         }
 57 #endif
 59         reach_dest_host_ = false;
 60         int ttl = 1;
 61         while (!reach_dest_host_ && max_hop_--)
 62         {
 63             const boost::asio::ip::unicast::hops option(ttl);
 64             socket_.set_option(option);
 66             boost::asio::ip::unicast::hops op;
 67             socket_.get_option(op);
 68             if( ttl !=  op.value() )
 69             {
 70                 std::cout << "TTL not set properly. Should be "
 71                     << ttl << " but was set to "
 72                     << op.value() << '.' << std::endl;
 73                 throw std::runtime_error("TTL not set properly");        
 74             }
 76             std::cout << std::setw(3) << ttl << std::flush;
 77             start_send();
 78             start_receive();
 80             ttl++;
 81         }//while
 82     }
 84 private:
 85     void start_send()
 86     {
 87         std::string body("\"Hello!\" from Asio ping.");
 89         // Create an ICMP header for an echo request.
 90         icmp_header echo_request;
 91         echo_request.type(icmp_header::echo_request);
 92         echo_request.code(0);
 93         echo_request.identifier(get_identifier());
 94         echo_request.sequence_number(++sequence_number_);
 95         compute_checksum(echo_request, body.begin(), body.end());
 97         // Encode the request packet.
 98         boost::asio::streambuf request_buffer;
 99         std::ostream os(&request_buffer);
100         os << echo_request << body;
102         // Send the request.
103         time_sent_ = posix_time::microsec_clock::universal_time();
104         socket_.send_to(request_buffer.data(), destination_);  
105     }
108     void start_receive()
109     {
110         // Discard any data already in the buffer.
111         reply_buffer_.consume(reply_buffer_.size());
113         // Wait for a reply. We prepare the buffer to receive up to 64KB.
114         boost::system::error_code ec;
115         boost::asio::socket_base::message_flags flags = 0;
116         size_t len = socket_.receive(reply_buffer_.prepare(65536), flags, ec);
118         handle_receive(len, ec);
119     }
121     void handle_receive(std::size_t length, boost::system::error_code& ec)
122     {
123         // The actual number of bytes received is committed to the buffer so that we





    
124         // can extract it using a std::istream object.
125         reply_buffer_.commit(length);
127         // Decode the reply packet.
128         std::istream is(&reply_buffer_);
129         ipv4_header ipv4_hdr;
130         is >> ipv4_hdr;
132         if(ec)
133         {
134             std::cout << std::setw(9) << '*' << '\t' << "Request timed out." << std::endl;
135             return;
136         }
138         posix_time::ptime now = posix_time::microsec_clock::universal_time();
139         long long dwRoundTripTime = (now - time_sent_).total_milliseconds();
141         if(dwRoundTripTime)
142         {
143             std::cout << std::setw(6) << dwRoundTripTime << " ms"  << std::flush;
144         }
145         else
146         {
147             std::cout << std::setw(6) << "<1" << " ms" << std::flush;
148         }
150         boost::this_thread::sleep(boost::posix_time::seconds(2)); 
152         std::cout << '\t' << ipv4_hdr.source_address() << std::endl;
154         // Print out some information about the reply packet.
155         if( ipv4_hdr.source_address().to_string() == destination_.address().to_string() )
156         {
157             reach_dest_host_ = true;
158             std::cout << std::endl;
159             std::cout << std::endl;
160             std::cout << "traceroute sucess!" << std::endl;
162             icmp_header icmp_hdr;
163             is >> icmp_hdr;
165             if (is && icmp_hdr.type() == icmp_header::echo_reply
166                 && icmp_hdr.identifier() == get_identifier()
167                 && icmp_hdr.sequence_number() == sequence_number_)
168             {
169                 // Print out some information about the reply packet.
170                 std::cout << length - ipv4_hdr.header_length()
171                  << " bytes from " << ipv4_hdr.source_address()
172                 << ": icmp_seq=" << icmp_hdr.sequence_number()
173                 << ", ttl=" << ipv4_hdr.time_to_live()
174                 << ", time=" << dwRoundTripTime << " ms"
175                 << std::endl;
176             }
177         }
178      }
180     static unsigned short get_identifier()
181     {
182 #if defined(BOOST_WINDOWS)
183         return static_cast<unsigned short>(::GetCurrentProcessId());
184 #else
185         return static_cast<unsigned short>(::getpid());
186 #endif
187     }
189     icmp::resolver resolver_;
190     icmp::endpoint destination_;
191     icmp::socket socket_;
192     unsigned short sequence_number_;
193     posix_time::ptime time_sent_;
194     boost::asio::streambuf reply_buffer_;
195     bool reach_dest_host_;
196     std::size_t max_hop_;
197 };
199 int main(int argc, char* argv[])
200 {
201     try
202     {
203         if(argc != 2)
204         {
205             std::cerr << "Usage: ping <host>" << std::endl;
206 #if !defined(BOOST_WINDOWS)
207             std::cerr << "(You may need to run this program as root.)" << std::endl;
208 #endif
209             return 1;
210         }
212         boost::asio::io_service io_service;
213         traceroute p(io_service, argv[1]);
214         io_service.run();
215     }
216     catch (std::exception& e)
217     {
218         std::cerr << "Exception: " << e.what() << std::endl;
219     }
220 }

这个源码实现使用了boost库附带的boost asio使用示例中的代码，下面也将这个例子中使用到的代码附上，方便使用。至于boost库的编译使用另请参考其他的文章。

下面是 ipv4_header.hpp ：