Linux_socket编程入门（C++）
参考资料
实现思路
Socket编程主要分为两部分，Server端以及Client端，以下依次从这两方面开始讲解。
Server端
需要完成的任务
- 创建嵌套字( socket() )
- 绑定嵌套字到IP地址以及端口上( bind() )
- 将嵌套字设置到监听模式监听请求( listen() )
- 请求到来后，接受请求，返回一个新的连接嵌套字( accept() )
- 进行通信( send()/recv() )
- 关闭嵌套字( close() )
所用到的一些函数以及结构
-
socketaddr_in:
- sin_family （地址簇）
- sin_port（端口）
- sin_addr（地址）
-
socket( domain, type, protocol):返回值为-1时连接失败
- domain (协议簇)
- type (数据传输类型)
- protocol (协议类型)
-
bind( sockfd, addr, addrlen)
- sockfd （嵌套字）
- addr （将地址赋值给嵌套字）
- addrlen （addr所指向结构体的字节长度）
-
listen( sock, backlog)
- sock ( 监听状态的嵌套字 )
- backlog ( 请求队列的最大长度 )
- accept( sock, sockaddr, addrlen):接受客户端请求
-
send( sock, buf, len, flag )
- sock（嵌套字）
- buf（所要发送数据，缓冲区大小）
- len（所要发送数据字节数）
- flags（发送数据时的选项）
- recv():类似于send()
Client端
需要完成的任务
- 创建嵌套字( socket() )
- 向服务器发送连接请求( connect() )
- 和服务器进行通信( send()/recv() )
- 关闭嵌套字( close() )
所用到的一些函数以及结构
- connec( sockfd, addr, addrlen)：返回值为-1时连接失败
源代码
server.cpp
#include <iostream>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
using namespace std;
int main()
{
int client, server;
int portNum = 1500;
bool isExit = false;
int bufsize = 1024;
char buffer[bufsize];
struct sockaddr_in server_addr;
socklen_t size;
//init socket.
client = socket(AF_INET, SOCK_STREAM, 0); //AF_INET指明使用TCP/IP协议簇
//SOCK_STREAM指明使用流式嵌套字
//使用default 协议类型
if (client < 0) //返回值为-1，连接失败
{
cout<<"=> Error establishing connection."<<endl;
exit(1);
}
cout<<"\n=> Socket server has been created."<<endl;
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = htons(INADDR_ANY); //INADDR_ANY能够收到任意一块网卡的连接
server_addr.sin_port = htons(portNum);
//binding socket
if(bind(client, (struct sockaddr*)&server_addr, sizeof(server_addr))<0)
{
cout<<"=> Error binding socket..."<<endl;
exit(1);
}
size = sizeof(server_addr);
cout<<"=> Looking for client"<<endl;
//listening socket
listen(client,1);
//accept client
server = accept(client, (struct sockaddr*)&server_addr,&size);
if(server < 0)
{
cout<<"=> Error on accepting..."<<endl;
exit(1);
}
while(server > 0)
{
strcpy(buffer,"Server connected...\n");
send(server, buffer, bufsize, 0);
cout<<"=> Connected with client..."<<endl;
cout<<"\n=> Enter # to end the connection\n"<<endl;
cout<<"Client: ";
do{
recv(server, buffer, bufsize, 0);
cout << buffer << " ";
if(*buffer == '#')
{
*buffer = '*';
isExit = true;
}
}while(*buffer != '*');
do{
cout<<"\nServer: ";
do{
cin >> buffer;
send(server, buffer, bufsize, 0);
if(*buffer == '#')
{
send(server, buffer, bufsize, 0);
*buffer = '*';
isExit = true;
}
}while (*buffer != '*');
cout<<"Client: ";
do{
recv(server, buffer, bufsize, 0);
cout << buffer <<" ";
if(*buffer == '#')
{
*buffer == '*';
isExit = true;
}
}while(*buffer != '*');
}while(!isExit);
cout<<"\n\n=> Connection terminated..."<< endl;
cout<<"=> Goodbye..." << endl;
isExit = false;
exit(1);
}
close(client);
return 0;
}
client.cpp
/*
Note the server doesn't need to know the clients port number
but the client needs to the servers port number
*/
#include <iostream>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
using namespace std;
int main()
{
int client, server;
int portNum = 1500; // note the server and clients Ip are the same
bool isExit = false;
int bufsize = 1024;
char buffer[bufsize];
// char *ip = "127.0.0.1";
struct sockaddr_in server_addr;
//init socket
client = socket(AF_INET, SOCK_STREAM, 0);
if (client < 0)
{
cout<<"\n=> Error creating socket."<<endl;
exit(1);
}
cout<<"\n=> Socket client has been created" <<endl;
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(portNum);
//connecting socket server
if(connect(client, (struct sockaddr*)&server_addr, sizeof(server_addr)) == 0)
{
cout << "=> Connecting to server..."<< endl;
}
recv(client, buffer, bufsize, 0);
cout<< "=> Connection confirmed" << endl;
cout<< "\n=> Enter # to end the connection\n" << endl;
do{
cout<<"Client: ";
do{
cin >> buffer;
send(client, buffer, bufsize, 0);
if(*buffer == '#')
{
send(client, buffer, bufsize, 0);
*buffer = '*';
isExit = true;
}
} while(*buffer != 42);
cout<<"Server: ";
do{
recv(client, buffer, bufsize, 0);
cout << buffer << " ";
if(*buffer == '#')
{
*buffer = '*';
isExit = true;
}
}while(*buffer != 42);
cout<<endl;
}while(!isExit);
cout<<"\nConnection terminated..."<< endl;
cout<<"Goodbye..." << endl;
close(client);
return 0;
}