boost asio icmp实现

1.icmp_header.h

//// icmp_header.hpp// ~~~~~~~~~~~~~~~//// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)//// Distributed under the Boost Software License, Version 1.0. (See accompanying// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)//#ifndef ICMP_HEADER_HPP#define ICMP_HEADER_HPP#include <istream>#include <ostream>#include <algorithm>// ICMP header for both IPv4 and IPv6.//// The wire format of an ICMP header is:// // 0               8               16                             31// +---------------+---------------+------------------------------+      ---// |               |               |                              |       ^// |     type      |     code      |          checksum            |       |// |               |               |                              |       |// +---------------+---------------+------------------------------+    8 bytes// |                               |                              |       |// |          identifier           |       sequence number        |       |// |                               |                              |       v// +-------------------------------+------------------------------+      ---class icmp_header{public:enum { echo_reply = 0, destination_unreachable = 3, source_quench = 4,redirect = 5, echo_request = 8, time_exceeded = 11, parameter_problem = 12,timestamp_request = 13, timestamp_reply = 14, info_request = 15,info_reply = 16, address_request = 17, address_reply = 18 };icmp_header() { std::fill(rep_, rep_ + sizeof(rep_), 0); }//std::fill 相当于memsetunsigned char type() const { return rep_[0]; }unsigned char code() const { return rep_[1]; }unsigned short checksum() const { return decode(2, 3); }unsigned short identifier() const { return decode(4, 5); }unsigned short sequence_number() const { return decode(6, 7); }void type(unsigned char n) { rep_[0] = n; }void code(unsigned char n) { rep_[1] = n; }void checksum(unsigned short n) { encode(2, 3, n); }void identifier(unsigned short n) { encode(4, 5, n); }void sequence_number(unsigned short n) { encode(6, 7, n); }friend std::istream& operator>>(std::istream& is, icmp_header& header)//>> 只能声明为友元函数，友元函数实际是全局函数{ return is.read(reinterpret_cast<char*>(header.rep_), 8); }// reinterpret_cast<char*>, friend std::ostream& operator<<(std::ostream& os, const icmp_header& header){ return os.write(reinterpret_cast<const char*>(header.rep_), 8); }private:unsigned short decode(int a, int b) const//decode 从字节流编程有意义的东西{ return (rep_[a] << 8) + rep_[b]; }void encode(int a, int b, unsigned short n)//encode 变成字节流{rep_[a] = static_cast<unsigned char>(n >> 8);//unsigned short -> unsigned charrep_[b] = static_cast<unsigned char>(n & 0xFF);}unsigned char rep_[8];};template <typename Iterator>void compute_checksum(icmp_header& header,Iterator body_begin, Iterator body_end){unsigned int sum = (header.type() << 8) + header.code()+ header.identifier() + header.sequence_number();Iterator body_iter = body_begin;while (body_iter != body_end){sum += (static_cast<unsigned char>(*body_iter++) << 8);if (body_iter != body_end)sum += static_cast<unsigned char>(*body_iter++);}sum = (sum >> 16) + (sum & 0xFFFF);sum += (sum >> 16);header.checksum(static_cast<unsigned short>(~sum));}#endif // ICMP_HEADER_HPP

2. ipv4_header.h

//// ipv4_header.hpp// ~~~~~~~~~~~~~~~//// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)//// Distributed under the Boost Software License, Version 1.0. (See accompanying// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)//#ifndef IPV4_HEADER_HPP#define IPV4_HEADER_HPP#include <algorithm>#include <boost/asio/ip/address_v4.hpp>// Packet header for IPv4.//// The wire format of an IPv4 header is:// // 0               8               16                             31// +-------+-------+---------------+------------------------------+      ---// |       |       |               |                              |       ^// |version|header |    type of    |    total length in bytes     |       |// |  (4)  | length|    service    |                              |       |// +-------+-------+---------------+-+-+-+------------------------+       |// |                               | | | |                        |       |// |        identification         |0|D|M|    fragment offset     |       |// |                               | |F|F|                        |       |// +---------------+---------------+-+-+-+------------------------+       |// |               |               |                              |       |// | time to live  |   protocol    |       header checksum        |   20 bytes// |               |               |                              |       |// +---------------+---------------+------------------------------+       |// |                                                              |       |// |                      source IPv4 address                     |       |// |                                                              |       |// +--------------------------------------------------------------+       |// |                                                              |       |// |                   destination IPv4 address                   |       |// |                                                              |       v// +--------------------------------------------------------------+      ---// |                                                              |       ^// |                                                              |       |// /                        options (if any)                      /    0 - 40// /                                                              /     bytes// |                                                              |       |// |                                                              |       v// +--------------------------------------------------------------+      ---class ipv4_header{public:ipv4_header() { std::fill(rep_, rep_ + sizeof(rep_), 0); }unsigned char version() const { return (rep_[0] >> 4) & 0xF; }unsigned short header_length() const { return (rep_[0] & 0xF) * 4; }unsigned char type_of_service() const { return rep_[1]; }unsigned short total_length() const { return decode(2, 3); }unsigned short identification() const { return decode(4, 5); }bool dont_fragment() const { return (rep_[6] & 0x40) != 0; }bool more_fragments() const { return (rep_[6] & 0x20) != 0; }unsigned short fragment_offset() const { return decode(6, 7) & 0x1FFF; }unsigned int time_to_live() const { return rep_[8]; }unsigned char protocol() const { return rep_[9]; }unsigned short header_checksum() const { return decode(10, 11); }boost::asio::ip::address_v4 source_address() const{boost::asio::ip::address_v4::bytes_type bytes= { { rep_[12], rep_[13], rep_[14], rep_[15] } };//ip地址怎么构造return boost::asio::ip::address_v4(bytes);}boost::asio::ip::address_v4 destination_address() const{boost::asio::ip::address_v4::bytes_type bytes= { { rep_[16], rep_[17], rep_[18], rep_[19] } };return boost::asio::ip::address_v4(bytes);}friend std::istream& operator>>(std::istream& is, ipv4_header& header){is.read(reinterpret_cast<char*>(header.rep_), 20);if (header.version() != 4)is.setstate(std::ios::failbit);// iostream.setstate 不太懂std::streamsize options_length = header.header_length() - 20;if (options_length < 0 || options_length > 40)is.setstate(std::ios::failbit);elseis.read(reinterpret_cast<char*>(header.rep_) + 20, options_length);return is;}private:unsigned short decode(int a, int b) const{ return (rep_[a] << 8) + rep_[b]; }unsigned char rep_[60];};#endif // IPV4_HEADER_HPP

3. main.cpp

//// ping.cpp// ~~~~~~~~//// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)//// Distributed under the Boost Software License, Version 1.0. (See accompanying// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)//#include <boost/asio.hpp>#include <boost/bind.hpp>#include <istream>#include <iostream>#include <ostream>#include "icmp_header.h"#include "ipv4_header.h"using boost::asio::ip::icmp;using boost::asio::deadline_timer;namespace posix_time = boost::posix_time;class pinger{public:pinger(boost::asio::io_service& io_service, const char* destination): resolver_(io_service), socket_(io_service, icmp::v4()),timer_(io_service), sequence_number_(0), num_replies_(0){icmp::resolver::query query(icmp::v4(), destination, "");destination_ = *resolver_.resolve(query);//目标地址start_send();start_receive();}private:void start_send(){std::string body("\"Hello!\" from Asio ping.");// Create an ICMP header for an echo request.icmp_header echo_request;echo_request.type(icmp_header::echo_request);echo_request.code(0);echo_request.identifier(get_identifier());echo_request.sequence_number(++sequence_number_);compute_checksum(echo_request, body.begin(), body.end());// Encode the request packet.boost::asio::streambuf request_buffer;std::ostream os(&request_buffer);os << echo_request << body;// Send the request.time_sent_ = posix_time::microsec_clock::universal_time();//boost 得到时间socket_.send_to(request_buffer.data(), destination_);// Wait up to five seconds for a reply.num_replies_ = 0;timer_.expires_at(time_sent_ + posix_time::seconds(5));timer_.async_wait(boost::bind(&pinger::handle_timeout, this));}void handle_timeout(){if (num_replies_ == 0)std::cout << "Request timed out" << std::endl;// Requests must be sent no less than one second apart.timer_.expires_at(time_sent_ + posix_time::seconds(1));timer_.async_wait(boost::bind(&pinger::start_send, this));}void start_receive(){// Discard any data already in the buffer.reply_buffer_.consume(reply_buffer_.size());//streambuf.comsume()清空// Wait for a reply. We prepare the buffer to receive up to 64KB.socket_.async_receive(reply_buffer_.prepare(65536),//准备缓冲区boost::bind(&pinger::handle_receive, this, _2));}void handle_receive(std::size_t length){// The actual number of bytes received is committed to the buffer so that we// can extract it using a std::istream object.reply_buffer_.commit(length);//转移到streambuf中，// Decode the reply packet.std::istream is(&reply_buffer_);ipv4_header ipv4_hdr;icmp_header icmp_hdr;is >> ipv4_hdr >> icmp_hdr;// We can receive all ICMP packets received by the host, so we need to// filter out only the echo replies that match the our identifier and// expected sequence number.if (is && icmp_hdr.type() == icmp_header::echo_reply&& icmp_hdr.identifier() == get_identifier()&& icmp_hdr.sequence_number() == sequence_number_){// If this is the first reply, interrupt the five second timeout.if (num_replies_++ == 0)timer_.cancel();// Print out some information about the reply packet.posix_time::ptime now = posix_time::microsec_clock::universal_time();std::cout << length - ipv4_hdr.header_length()<< " bytes from " << ipv4_hdr.source_address()<< ": icmp_seq=" << icmp_hdr.sequence_number()<< ", ttl=" << ipv4_hdr.time_to_live()<< ", time=" << (now - time_sent_).total_milliseconds() << " ms"<< std::endl;}start_receive();}static unsigned short get_identifier(){#if defined(BOOST_ASIO_WINDOWS)return static_cast<unsigned short>(::GetCurrentProcessId());//全局函数，widows api，得到进程id#elsereturn static_cast<unsigned short>(::getpid());//linux#endif}icmp::resolver resolver_;icmp::endpoint destination_;icmp::socket socket_;deadline_timer timer_;unsigned short sequence_number_;posix_time::ptime time_sent_;boost::asio::streambuf reply_buffer_;std::size_t num_replies_;};int main(int argc, char* argv[]){try{if (argc != 2){std::cerr << "Usage: ping <host>" << std::endl;#if !defined(BOOST_ASIO_WINDOWS)std::cerr << "(You may need to run this program as root.)" << std::endl;#endifreturn 1;}boost::asio::io_service io_service;pinger p(io_service, argv[1]);io_service.run();}catch (std::exception& e){std::cerr << "Exception: " << e.what() << std::endl;}}