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淄博云天网站建设推广,seo搜索引擎优化业务,高端的网站建设,网站建设中企网络协议初识所谓的协议就是人们为了通信的一种约定操作系统要进行协议管理,必然会先描述,再组织协议本质就是软件,软件是可以"分层"协议在设计的时候,就是被层状的划分的, 为什么要划分成为层状结构场景复杂功能解耦(便于人们进行各种维护)OSI七层模型局域网中…

网络协议初识

所谓的协议就是人们为了通信的一种约定
操作系统要进行协议管理,必然会先描述,再组织
协议本质就是软件,软件是可以"分层"
协议在设计的时候,就是被层状的划分的,

为什么要划分成为层状结构

场景复杂
功能解耦(便于人们进行各种维护)

OSI七层模型

局域网中两台主机是可以直接通信的

每层都有自己的协议定制方案,
每层协议都要有自己的协议报头
从上到下交付数据的时候,要添加报头
从下到上递交数据的时候,要去掉报头

如何理解报头

报头就像快递的快递单号一样,虽然我们不看,但是必须有
封装的本质: 添加报头
解包: 去掉报头&&展开分析

在使用TCP/IP协议的网络中,IP及其向上的协议,看到的报文都是一样的

报文是要被封装的,如何解包?
决定我们的有效载荷交付给上层的哪一个协议的问题?
每一个协议都要考虑,都要有一定的方式解决这两个公共问题

理解源IP地址和目的IP地址

把数据哦送到对方的机器不是目的,真正的网络通信: 其实是进程间通信
IP地址(公网IP),标定了主机的唯一性
源IP是固定不变的,目的IP是可以变的

认识端口号

端口号是标识特定主机上的网络进程的唯一性
端口号是一个2字节16位的整数
端口号用来标识一个进程, 告诉操作系统, 当前的这个数据要交给哪一个进程来处理;
IP地址 + 端口号能够标识网络上的某一台主机的某一个进程;
一个端口号只能被一个进程占用

socket编程接口

常见的套接字:

域间socket
原始socket
网络socket

理论上,是三种应用场景,对应的应该是三套接口,不过将所有的接口进行统一

使用网络在两台主机之间进行通信(之间互发信息)

log.hpp

#pragma once#include <iostream>
#include <cstdio>
#include <cstdarg>
#include <ctime>
#include <string>// 日志是有日志级别的
#define DEBUG   0
#define NORMAL  1
#define WARNING 2
#define ERROR   3
#define FATAL   4const char *gLevelMap[] = {"DEBUG","NORMAL","WARNING","ERROR","FATAL"
};// #define LOGFILE "./threadpool.log"// 完整的日志功能，至少: 日志等级 时间 支持用户自定义(日志内容, 文件行，文件名)
void logMessage(int level, const char *format, ...)
{
#ifndef DEBUG_SHOWif(level== DEBUG) return;
#endifchar stdBuffer[1024]; //标准部分time_t timestamp = time(nullptr);snprintf(stdBuffer, sizeof stdBuffer, "[%s] [%ld] ", gLevelMap[level], timestamp);char logBuffer[1024]; //自定义部分va_list args;va_start(args, format);vsnprintf(logBuffer, sizeof logBuffer, format, args);va_end(args);printf("%s%s\n", stdBuffer, logBuffer);
}

Makefile

.PHONY:all
all:udp_client udp_serverudp_client:udp_client.ccg++ -o $@ $^ -std=c++11 
udp_server:udp_server.ccg++ -o $@ $^ -std=c++11.PHONY:clean
clean:rm -f udp_client udp_server

udp_client.cc

#include <iostream>
#include <string>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <memory>
uint16_t serverport = 0;
std::string serverip;static void usage(std::string proc)
{std::cout << "\nUsage: " << proc << " serverIp serverPort\n"<< std::endl;
}// ./udp_client 127.0.0.1 8080
int main(int argc, char *argv[])
{if (argc != 3){usage(argv[0]);exit(1);}// 1.创建套接字int sock = socket(AF_INET, SOCK_DGRAM, 0);if (sock < 0){std::cerr << "socket error" << std::endl;exit(2);}serverport = atoi(argv[2]);serverip = argv[1];// client一般不需要显示的bind指定port，而是让OS自动随机选择(什么时候做的呢？)std::string message;struct sockaddr_in server;memset(&server, 0, sizeof(server));// 清0server.sin_family = AF_INET;server.sin_port = htons(atoi(argv[2]));server.sin_addr.s_addr = inet_addr(argv[1]);char buffer[1024];while(true){//多线程std::cout << "请输入你的信息# ";std::getline(std::cin, message);if(message == "quit") break;// 当client首次发送消息给服务器的时候，OS会自动给client bind他的IP和PORTsendto(sock, message.c_str(), message.size(), 0, (struct sockaddr*)&server, sizeof server);struct sockaddr_in temp;socklen_t len = sizeof(temp);ssize_t s = recvfrom(sock, buffer, sizeof buffer, 0, (struct sockaddr*)&temp, &len);if(s > 0){buffer[s] = 0;std::cout << "server echo# " << buffer << std::endl;}}return 0;
}

udp_server.cc

#include "udp_server.hpp"
#include <memory>
#include <cstdlib>static void usage(std::string proc)
{std::cout << "\nUsage: " << proc << " port\n" << std::endl;
}// ./udp_server ip port //云服务器的问题 bug??
int main(int argc, char *argv[])
{if(argc != 2){usage(argv[0]);exit(1);}// std::string ip = argv[1];uint16_t port = atoi(argv[1]);// 字符串->整数// unique_ptr智能指针std::unique_ptr<UdpServer> svr(new UdpServer(port));svr->initServer();svr->Start();return 0;
}

udp_server.hpp

#ifndef _UDP_SERVER_HPP
#define _UDP_SERVER_HPP#include "log.hpp"
#include <iostream>
#include <unordered_map>
#include <cstdio>
#include <string>
#include <cerrno>
#include <cstring>
#include <cstdlib>
#include <strings.h>
#include <sys/types.h>
#include <queue>// 网络的常用的四个接口
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>#define SIZE 1024class UdpServer
{
public:UdpServer(uint16_t port, std::string ip = "") : _port(port), _ip(ip), _sock(-1){}// 初始化bool initServer(){//  1. 创建套接字_sock = socket(AF_INET, SOCK_DGRAM, 0);if (_sock < 0){logMessage(FATAL, "%d:%s", errno, strerror(errno));exit(2);}// 2. bind: 将用户设置的ip和port在内核中和我们当前的进程强关联struct sockaddr_in local;// sockaddr_in域间套接字bzero(&local, sizeof(local));// 清0local.sin_family = AF_INET;// 服务器的IP和端口未来也是要发送给对方主机的 -> 先要将数据发送到网络！// 主机序列->网络序列local.sin_port = htons(_port);//INADDR_ANY表示让服务器在工作过程中，可以从任意IP中获取数据//inet_add表示将点分十进制字符串(192.168.110.132)风格的IP地址->4字节主机序列->网络序列local.sin_addr.s_addr = _ip.empty() ? INADDR_ANY : inet_addr(_ip.c_str());if (bind(_sock, (struct sockaddr *)&local, sizeof(local)) < 0){logMessage(FATAL, "%d:%s", errno, strerror(errno));exit(2);}logMessage(NORMAL, "init udp server done ... %s", strerror(errno));// donereturn true;}void Start(){// 服务器启动-> 进程 -> 常驻进程 -> 永远在内存中存在，除非挂了！// echo server: client给我们发送消息，我们原封不动返回char buffer[SIZE];for (;;){// 注意：peer是纯输出型参数struct sockaddr_in peer;bzero(&peer, sizeof(peer));// 输入: peer缓冲区大小// 输出: 实际读到的peersocklen_t len = sizeof(peer);ssize_t s = recvfrom(_sock, buffer, sizeof(buffer) - 1, 0, (struct sockaddr *)&peer, &len);if (s > 0){buffer[s] = 0; // 我们目前数据当做字符串uint16_t cli_port = ntohs(peer.sin_port);      // 从网络中来的！std::string cli_ip = inet_ntoa(peer.sin_addr); // 4字节的网络序列的IP->本主机的字符串风格的IP，方便显示printf("[%s:%d]# %s\n", cli_ip.c_str(), cli_port, buffer);}// 分析和处理数据，TODO// end. 写回数据sendto(_sock, buffer, strlen(buffer), 0, (struct sockaddr *)&peer, len);}}~UdpServer(){if (_sock >= 0)close(_sock);}private:// 一个服务器，一般必须需要ip地址和port(16位的整数)uint16_t _port;// 端口号std::string _ip;// ip地址int _sock;// 套接字
};
#endif

使用网络在两台主机之间进行通信(交互式的命令)

void Start(){// 服务器启动-> 进程 -> 常驻进程 -> 永远在内存中存在，除非挂了！// echo server: client给我们发送消息，我们原封不动返回char buffer[SIZE];for (;;){// 注意：peer是纯输出型参数struct sockaddr_in peer;bzero(&peer, sizeof(peer));// 输入: peer缓冲区大小// 输出: 实际读到的peersocklen_t len = sizeof(peer);ssize_t s = recvfrom(_sock, buffer, sizeof(buffer) - 1, 0, (struct sockaddr *)&peer, &len);char result[256];char key[64];std::string cmd_echo;if (s > 0){buffer[s] = 0; // 我们目前数据当做字符串uint16_t cli_port = ntohs(peer.sin_port);      // 从网络中来的！std::string cli_ip = inet_ntoa(peer.sin_addr); // 4字节的网络序列的IP->本主机的字符串风格的IP，方便显示// 你发过来的字符串是指令 ls -a -l, rm -rm ~if(strcasestr(buffer, "rm") != nullptr || strcasestr(buffer, "rmdir") != nullptr){std::string err_message = "坏人.... ";std::cout << err_message << buffer << std::endl;sendto(_sock, err_message.c_str(), err_message.size(), 0, (struct sockaddr *)&peer, len);continue;}FILE *fp = popen(buffer, "r");if (nullptr == fp){logMessage(ERROR, "popen: %d:%s", errno, strerror(errno));continue;}while (fgets(result, sizeof(result), fp) != nullptr){cmd_echo += result;}fclose(fp);// printf("[%s:%d]# %s\n", cli_ip.c_str(), cli_port, buffer);}// 分析和处理数据，TODO// end. 写回数据sendto(_sock, cmd_echo.c_str(), cmd_echo.size(), 0, (struct sockaddr *)&peer, len);}

使用网络在两台主机之间进行通信(多进程)

makeflie

.PHONY:all
all:udp_client udp_serverudp_client:udp_client.ccg++ -o $@ $^ -std=c++11 -lpthread 
udp_server:udp_server.ccg++ -o $@ $^ -std=c++11.PHONY:clean
clean:rm -f udp_client udp_server

log.hpp

#pragma once#include <iostream>
#include <cstdio>
#include <cstdarg>
#include <ctime>
#include <string>// 日志是有日志级别的
#define DEBUG   0
#define NORMAL  1
#define WARNING 2
#define ERROR   3
#define FATAL   4const char *gLevelMap[] = {"DEBUG","NORMAL","WARNING","ERROR","FATAL"
};// #define LOGFILE "./threadpool.log"// 完整的日志功能，至少: 日志等级 时间 支持用户自定义(日志内容, 文件行，文件名)
void logMessage(int level, const char *format, ...)
{
#ifndef DEBUG_SHOWif(level== DEBUG) return;
#endifchar stdBuffer[1024]; //标准部分time_t timestamp = time(nullptr);snprintf(stdBuffer, sizeof stdBuffer, "[%s] [%ld] ", gLevelMap[level], timestamp);char logBuffer[1024]; //自定义部分va_list args;va_start(args, format);vsnprintf(logBuffer, sizeof logBuffer, format, args);va_end(args);printf("%s%s\n", stdBuffer, logBuffer);
}

thread.hpp

#pragma once
#include <iostream>
#include <string>
#include <functional>
#include <cstdio>// typedef std::function<void* (void*)> fun_t;
typedef void *(*fun_t)(void *);class ThreadData
{
public:void *args_;std::string name_;
};class Thread
{
public:Thread(int num, fun_t callback, void *args) : func_(callback){char nameBuffer[64];snprintf(nameBuffer, sizeof nameBuffer, "Thread-%d", num);name_ = nameBuffer;tdata_.args_ = args;tdata_.name_ = name_;}void start(){pthread_create(&tid_, nullptr, func_, (void*)&tdata_);}void join(){pthread_join(tid_, nullptr);}std::string name(){return name_;}~Thread(){}private:std::string name_;fun_t func_;ThreadData tdata_;pthread_t tid_;
};

udp_client.cc

#include <iostream>
#include <string>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <memory>
#include "thread.hpp"uint16_t serverport = 0;
std::string serverip;static void usage(std::string proc)
{std::cout << "\nUsage: " << proc << " serverIp serverPort\n"<< std::endl;
}static void *udpSend(void *args)
{int sock = *(int *)((ThreadData *)args)->args_;std::string name = ((ThreadData *)args)->name_;std::string message;struct sockaddr_in server;memset(&server, 0, sizeof(server));server.sin_family = AF_INET;server.sin_port = htons(serverport);server.sin_addr.s_addr = inet_addr(serverip.c_str());while (true){std::cerr << "请输入你的信息# "; //标准错误 2打印std::getline(std::cin, message);if (message == "quit")break;// 当client首次发送消息给服务器的时候，OS会自动给client bind他的IP和PORT// sendto表示发送报文sendto(sock, message.c_str(), message.size(), 0, (struct sockaddr *)&server, sizeof server);}return nullptr;
}static void *udpRecv(void *args)
{int sock = *(int *)((ThreadData *)args)->args_;std::string name = ((ThreadData *)args)->name_;char buffer[1024];while (true){memset(buffer, 0, sizeof(buffer));struct sockaddr_in temp;socklen_t len = sizeof(temp);// recvfrom接收解决报文ssize_t s = recvfrom(sock, buffer, sizeof buffer, 0, (struct sockaddr *)&temp, &len);if (s > 0){buffer[s] = 0;std::cout  << buffer << std::endl;}}
}// ./udp_client 127.0.0.1 8080
int main(int argc, char *argv[])
{if (argc != 3){usage(argv[0]);exit(1);}int sock = socket(AF_INET, SOCK_DGRAM, 0);if (sock < 0){std::cerr << "socket error" << std::endl;exit(2);}serverport = atoi(argv[2]);serverip = argv[1];std::unique_ptr<Thread> sender(new Thread(1, udpSend, (void *)&sock));std::unique_ptr<Thread> recver(new Thread(2, udpRecv, (void *)&sock));// sender->name();sender->start();recver->start();sender->join();recver->join();close(sock);return 0;
}

udp_server.cc

#include "udp_server.hpp"
#include <memory>
#include <cstdlib>static void usage(std::string proc)
{std::cout << "\nUsage: " << proc << " port\n" << std::endl;
}int main(int argc, char *argv[])
{if(argc != 2){usage(argv[0]);exit(1);}uint16_t port = atoi(argv[1]);std::unique_ptr<UdpServer> svr(new UdpServer(port));svr->initServer();svr->Start();return 0;
}

udp_server.hpp

#ifndef _UDP_SERVER_HPP
#define _UDP_SERVER_HPP#include "log.hpp"
#include <iostream>
#include <unordered_map>
#include <cstdio>
#include <string>
#include <cerrno>
#include <cstring>
#include <cstdlib>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <queue>#define SIZE 1024class UdpServer
{
public:UdpServer(uint16_t port, std::string ip = "") : _port(port), _ip(ip), _sock(-1){}bool initServer(){//  1. 创建套接字_sock = socket(AF_INET, SOCK_DGRAM, 0); if (_sock < 0){logMessage(FATAL, "%d:%s", errno, strerror(errno));exit(2);}// 2. bind: 将用户设置的ip和port在内核中和我们当前的进程强关联struct sockaddr_in local;bzero(&local, sizeof(local));// 清0local.sin_family = AF_INET;local.sin_port = htons(_port);// 转换local.sin_addr.s_addr = _ip.empty() ? INADDR_ANY : inet_addr(_ip.c_str());// 转换if (bind(_sock, (struct sockaddr *)&local, sizeof(local)) < 0){logMessage(FATAL, "%d:%s", errno, strerror(errno));exit(2);}logMessage(NORMAL, "init udp server done ... %s", strerror(errno));return true;}void Start(){char buffer[SIZE];for (;;){// 注意：//  peer,纯输出型参数struct sockaddr_in peer;// 输出型参数bzero(&peer, sizeof(peer));socklen_t len = sizeof(peer);char result[256];char key[64];std::string cmd_echo;// recvfrom读取报文ssize_t s = recvfrom(_sock, buffer, sizeof(buffer) - 1, 0, (struct sockaddr *)&peer, &len);if (s > 0){buffer[s] = 0; // 我们目前数据当做字符串uint16_t cli_port = ntohs(peer.sin_port);// 转换std::string cli_ip = inet_ntoa(peer.sin_addr);// 转换snprintf(key, sizeof(key), "%s-%u", cli_ip.c_str(), cli_port); // 127.0.0.1-8080logMessage(NORMAL, "key: %s", key);auto it = _users.find(key);if (it == _users.end()){// 不存在插入logMessage(NORMAL, "add new user : %s", key);_users.insert({key, peer});}}for (auto &iter : _users){std::string sendMessage = key;sendMessage += "# ";sendMessage += buffer; // 127.0.0.1-1234# 你好logMessage(NORMAL, "push message to %s", iter.first.c_str());sendto(_sock, sendMessage.c_str(), sendMessage.size(), 0, (struct sockaddr *)&(iter.second), sizeof(iter.second));}}}~UdpServer(){if (_sock >= 0)close(_sock);}private:// 一个服务器，一般必须需要ip地址和port(16位的整数)uint16_t _port;std::string _ip;int _sock;std::unordered_map<std::string, struct sockaddr_in> _users;std::queue<std::string> messageQueue;
};#endif

netstat -antp// 查看网络进程服务
无论是多线程读还是写,用的sock都是一个,
sock代表的就是文件,udp是全双工的,可以同时进行收发而不受干扰

使用网络在两台主机之间进行通信(多进程-父子进程):tcp实现

tcp_server.hpp

#pragma once#include <iostream>
#include <string>
#include <cstring>
#include <cerrno>
#include <cassert>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include "log.hpp"static void service(int sock, const std::string &clientip, const uint16_t &clientport)
{//echo serverchar buffer[1024];while(true){// read && write 可以直接被使用！ssize_t s = read(sock, buffer, sizeof(buffer)-1);if(s > 0){buffer[s] = 0; //将发过来的数据当做字符串std::cout << clientip << ":" << clientport << "# " << buffer << std::endl;}else if(s == 0) //对端关闭连接{logMessage(NORMAL, "%s:%d shutdown, me too!", clientip.c_str(), clientport);break;}else{ // logMessage(ERROR, "read socket error, %d:%s", errno, strerror(errno));break;}write(sock, buffer, strlen(buffer));}
}class TcpServer
{
private:const static int gbacklog = 20;
public:TcpServer(uint16_t port, std::string ip=""):listensock(-1), _port(port), _ip(ip){}void initServer(){// 1. 创建socket -- 进程和文件listensock = socket(AF_INET, SOCK_STREAM, 0);if(listensock < 0){logMessage(FATAL, "create socket error, %d:%s", errno, strerror(errno));exit(2);}logMessage(NORMAL, "create socket success, listensock: %d", listensock); // 3// 2. bind -- 文件 + 网络struct sockaddr_in local;memset(&local, 0, sizeof local);local.sin_family = AF_INET;local.sin_port = htons(_port);local.sin_addr.s_addr = _ip.empty() ? INADDR_ANY : inet_addr(_ip.c_str());if(bind(listensock, (struct sockaddr*)&local, sizeof(local)) < 0){logMessage(FATAL, "bind error, %d:%s", errno, strerror(errno));exit(3);}// 3. 因为TCP是面向连接的，当我们正式通信的时候，需要先建立连接if(listen(listensock, gbacklog) < 0){logMessage(FATAL, "listen error, %d:%s", errno, strerror(errno));exit(4);}logMessage(NORMAL, "init server success");}void start(){// 对SIGCHLD，主动忽略SIGCHLD信号，子进程退出的时候，会自动释放自己的僵尸状态signal(SIGCHLD, SIG_IGN); while(true){// sleep(1);// 4. 获取连接struct sockaddr_in src;socklen_t len = sizeof(src);int servicesock = accept(listensock, (struct sockaddr*)&src, &len);if(servicesock < 0){logMessage(ERROR, "accept error, %d:%s", errno, strerror(errno));continue;}// 获取连接成功了uint16_t client_port = ntohs(src.sin_port);std::string client_ip = inet_ntoa(src.sin_addr);logMessage(NORMAL, "link success, servicesock: %d | %s : %d |\n",\servicesock, client_ip.c_str(), client_port);// 开始进行通信服务啦// 多进程版 --- 创建子进程pid_t id = fork();assert(id != -1);if(id == 0){// 子进程是来进行提供服务的，需不需要知道监听socket呢？close(listensock);service(servicesock, client_ip, client_port);exit(0); // 僵尸状态}close(servicesock); // 如果父进程关闭servicesock，会不会影响子进程？？}}~TcpServer(){}
private:uint16_t _port;std::string _ip;int listensock;// 监听套接字
};

tcp_server.cc

#include "tcp_server.hpp"
#include <memory>static void usage(std::string proc)
{std::cout << "\nUsage: " << proc << " port\n" << std::endl;
}// ./tcp_server port
int main(int argc, char *argv[])
{if(argc != 2){usage(argv[0]);exit(1);}uint16_t port = atoi(argv[1]);std::unique_ptr<TcpServer> svr(new TcpServer(port));svr->initServer();svr->start();return 0;
}

telnet ip 端口号// 创建临时客户端
while :; do ps ajx | grep tcp-server;echo "####";sleep 1;done

tcp_client.cc

#include <iostream>
#include <string>
#include <cstdio>
#include <cstring>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>void usage(std::string proc)
{std::cout << "\nUsage: " << proc << " serverIp serverPort\n"<< std::endl;
}// ./tcp_client targetIp targetPort
int main(int argc, char *argv[])
{if (argc != 3){usage(argv[0]);exit(1);}std::string serverip = argv[1];uint16_t serverport = atoi(argv[2]);bool alive = false;int sock = 0;std::string line;while (true) // TODO{if (!alive){sock = socket(AF_INET, SOCK_STREAM, 0);if (sock < 0){std::cerr << "socket error" << std::endl;exit(2);}// client 要不要bind呢？不需要显示的bind，但是一定是需要port// 需要让os自动进行port选择// 连接别人的能力！struct sockaddr_in server;memset(&server, 0, sizeof(server));server.sin_family = AF_INET;server.sin_port = htons(serverport);server.sin_addr.s_addr = inet_addr(serverip.c_str());if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0){std::cerr << "connect error" << std::endl;exit(3); // TODO}std::cout << "connect success" << std::endl;alive = true;}std::cout << "请输入# ";std::getline(std::cin, line);if (line == "quit")break;ssize_t s = send(sock, line.c_str(), line.size(), 0);if (s > 0){char buffer[1024];ssize_t s = recv(sock, buffer, sizeof(buffer) - 1, 0);if (s > 0){buffer[s] = 0;std::cout << "server 回显# " << buffer << std::endl;}else if (s == 0){alive = false;close(sock);}}else{alive = false;close(sock);}}return 0;
}