[转][linux]简单的linux下的tcp/udp

转自：https://blog.csdn.net/cabing2005/article/details/53068880

详细函数以及参数解释请看原链接。

windows下的tcp/udp参考：http://www.cnblogs.com/lyggqm/p/6558002.html

TCP SERVER:

//
//  main.cpp
//  linux_socket_api
//
//  Created by bikang on 16/11/2.
//  Copyright (c) 2016年 bikang. All rights reserved.
//

#include <iostream>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>

//using namespace std;

#define BUFFER_SIZE 1024

void tsocket(int argc, const char * argv[]);

int main(int argc, const char * argv[]) {
    tsocket(argc,argv);
    return ;
}
void tsocket(int argc, const char * argv[]){
    if(argc < ){
        exit(-);
    }

    const char* ip = argv[];
    int port = atoi(argv[]);
    int backlog = atoi(argv[]);

    std::cout << "ip=" << ip << " port="<<port << " backlog=" << backlog  << std::endl;

    int fd;
    int check_ret;

    fd = socket(PF_INET,SOCK_STREAM , );
    assert(fd >= );

    struct sockaddr_in address;
    bzero(&address,sizeof(address));

    //转换成网络地址
    address.sin_port = htons(port);
    address.sin_family = AF_INET;
    //地址转换
    inet_pton(AF_INET, ip, &address.sin_addr);
    //设置socket buffer大小
    int recvbuf = ;
    int len = sizeof( recvbuf );
    setsockopt( fd, SOL_SOCKET, SO_RCVBUF, &recvbuf, sizeof( recvbuf ) );
    getsockopt( fd, SOL_SOCKET, SO_RCVBUF, &recvbuf, ( socklen_t* )&len );
    printf( "the receive buffer size after settting is %d\n", recvbuf );

    //绑定ip和端口
    check_ret = bind(fd,(struct sockaddr*)&address,sizeof(address));
    assert(check_ret >= );

    //创建监听队列，用来存放待处理的客户连接
    check_ret = listen(fd, backlog);
    assert(check_ret >= );

    struct sockaddr_in addressClient;
    socklen_t clientLen = sizeof(addressClient);
    //接受连接，阻塞函数
    int connfd = accept(fd, (struct sockaddr*)&addressClient, &clientLen);
    if(connfd < ){
        std::cout << "accept error";
    }else{
        //打印客户端信息
        char showData[INET_ADDRSTRLEN];
        std::cout <<inet_ntop(AF_INET,&addressClient.sin_addr,showData,INET_ADDRSTRLEN)<<":" <<ntohs(addressClient.sin_port)<<std::endl;

        //接受数据
        const int BUF_LEN = ;
        char sockBuf[BUF_LEN];
        size_t ret;

        memset(sockBuf, '\0', BUF_LEN);
        ret = recv(connfd, sockBuf, BUF_LEN-, );
        printf("ret=%ld,msg=%s\n",ret,sockBuf);

        memset(sockBuf, '\0', BUF_LEN);
        ret = recv(connfd, sockBuf, BUF_LEN-, MSG_OOB);
        printf("ret=%ld,msg=%s\n",ret,sockBuf);

        memset(sockBuf, '\0', BUF_LEN);
        ret = recv(connfd, sockBuf, BUF_LEN-, );
        printf("ret=%ld,msg=%s\n",ret,sockBuf);

        //获取本地socket信息
        struct sockaddr_in tmpAddress;
        clientLen = sizeof(tmpAddress);
        getsockname(fd, (struct sockaddr*)&tmpAddress, &clientLen);
        std::cout <<inet_ntop(AF_INET,&tmpAddress.sin_addr,showData,INET_ADDRSTRLEN)<<":" <<ntohs(tmpAddress.sin_port)<<std::endl;
        //获取远端socket信息
        getpeername(connfd,(struct sockaddr*)&tmpAddress, &clientLen );
        std::cout <<inet_ntop(AF_INET,&tmpAddress.sin_addr,showData,INET_ADDRSTRLEN)<<":" <<ntohs(tmpAddress.sin_port)<<std::endl;

        close(connfd);
    }

    close(fd);
}

TCP CLIENT:

//
//  main.cpp
//  linux_socket_api_client
//
//  Created by bikang on 16/11/2.
//  Copyright (c) 2016年 bikang. All rights reserved.
//
#include <iostream>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>

void tserver(int argc, const char * argv[]);

int main(int argc, const char * argv[]) {
    tserver(argc,argv);
    return ;
}
void tserver(int argc, const char * argv[]){
    std::cout << "t server" << std::endl;
    if(argc < ){
        exit(-);
    }

    const char* ip = argv[];
    int port = atoi(argv[]);
    int backlog = atoi(argv[]);

    std::cout << "ip=" << ip << " port="<<port << " backlog=" << backlog  << std::endl;

    int fd;
    int check_ret;

    fd = socket(PF_INET,SOCK_STREAM , );
    assert(fd >= );

    int sendbuf = ;
    int len = sizeof( sendbuf );
    setsockopt( fd, SOL_SOCKET, SO_SNDBUF, &sendbuf, sizeof( sendbuf ) );
    getsockopt( fd, SOL_SOCKET, SO_SNDBUF, &sendbuf, ( socklen_t* )&len );
    printf( "the send buffer size after settting is %d\n", sendbuf );

    struct sockaddr_in address;
    bzero(&address,sizeof(address));

    //转换成网络地址
    address.sin_port = htons(port);
    address.sin_family = AF_INET;
    //地址转换
    inet_pton(AF_INET, ip, &address.sin_addr);
    check_ret = connect(fd, (struct sockaddr*) &address, sizeof(address));
    assert(check_ret >= );
    //发送数据
    const char* oob_data = "abc";
    const char* normal_data = "my boy!";

    send(fd, normal_data, strlen(normal_data), );
    send(fd, oob_data, strlen(oob_data), MSG_OOB);
    send(fd, normal_data, strlen(normal_data), );

    close(fd);
}

UDP SERVER:

#include <iostream>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>

//using namespace std;

#define BUFFER_SIZE 1024

void tsocket(int argc, const char * argv[]);

int main(int argc, const char * argv[]) {
    tsocket(argc,argv);
    return ;
}
void tsocket(int argc, const char * argv[]){
    if(argc < ){
        exit(-);
    }

    const char* ip = argv[];
    int port = atoi(argv[]);
    int backlog = atoi(argv[]);

    std::cout << "ip=" << ip << " port="<<port << " backlog=" << backlog  << std::endl;

    int fd;
    int check_ret;

    fd = socket(PF_INET,SOCK_DGRAM , );
    assert(fd >= );

    struct sockaddr_in address;
    bzero(&address,sizeof(address));

    //转换成网络地址
    address.sin_port = htons(port);
    address.sin_family = AF_INET;
    //地址转换
    inet_pton(AF_INET, ip, &address.sin_addr);

    //绑定ip和端口
    check_ret = bind(fd,(struct sockaddr*)&address,sizeof(address));
    assert(check_ret >= );

    while(){

        char buffer[BUFFER_SIZE];
        struct sockaddr_in addressClient;
        socklen_t clientLen = sizeof(addressClient);
        memset(buffer, '\0', BUFFER_SIZE);
        //获取信息
        if(recvfrom(fd, buffer, BUFFER_SIZE-,,(struct sockaddr*)&addressClient, &clientLen) == -)
        {
           perror("Receive Data Failed:");
           exit();
        }
        printf("buffer=%s\n", buffer);
    }
    close(fd);
}

UDP CLIENT:

//
//  main.cpp
//  linux_socket_api_client
//
//  Created by bikang on 16/11/2.
//  Copyright (c) 2016年 bikang. All rights reserved.
//
#include <iostream>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>

void tserver(int argc, const char * argv[]);

int main(int argc, const char * argv[]) {
    tserver(argc,argv);
    return ;
}
void tserver(int argc, const char * argv[]){
    std::cout << "t server" << std::endl;
    if(argc < ){
        exit(-);
    }

    const char* ip = argv[];
    int port = atoi(argv[]);
    int backlog = atoi(argv[]);

    std::cout << "ip=" << ip << " port="<<port << " backlog=" << backlog  << std::endl;

    int fd;
    int check_ret;

    fd = socket(PF_INET,SOCK_DGRAM , );
    assert(fd >= );

    struct sockaddr_in address;
    bzero(&address,sizeof(address));

    //转换成网络地址
    address.sin_port = htons(port);
    address.sin_family = AF_INET;
    //地址转换
    inet_pton(AF_INET, ip, &address.sin_addr);
    //发送数据
    const char* normal_data = "my boy!";
    if(sendto(fd, normal_data, strlen(normal_data),,(struct sockaddr*)&address,sizeof(address)) < )
    {
      perror("Send File Name Failed:");
      exit();
    }
    close(fd);
}

另附：

linux网络编程常用头文件：

sys/types.h：数据类型定义

sys/socket.h：提供socket函数及数据结构

netinet/in.h：定义数据结构sockaddr_in

arpa/inet.h：提供IP地址转换函数

netdb.h：提供设置及获取域名的函数

sys/ioctl.h：提供对I/O控制的函数

sys/poll.h：提供socket等待测试机制的函数

其他在网络程序中常见的头文件 
unistd.h：提供通用的文件、目录、程序及进程操作的函数

errno.h：提供错误号errno的定义，用于错误处理

fcntl.h：提供对文件控制的函数

time.h：提供有关时间的函数

crypt.h：提供使用DES加密算法的加密函数

pwd.h：提供对/etc/passwd文件访问的函数

shadow.h：提供对/etc/shadow文件访问的函数

pthread.h：提供多线程操作的函数

signal.h：提供对信号操作的函数

sys/wait.h、sys/ipc.h、sys/shm.h：提供进程等待、进程间通讯（IPC）及共享内存的函数

在编写网络程序时，可以直接使用下面这段头文件代码

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <malloc.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <stdarg.h>
#include <fcntl.h>
#include <fcntl.h>

涉及到用户权限及密码验证问题时加入如下语句：
#include <shadow.h>
#include <crypt.h>
#include <pwd.h> 
需要注意的是，应该在编译时链接加密算法库，即增加编译选项：
-lcrypt

涉及到文件及时间操作加入如下语句： 
#include <sys/time.h>
#include <utime.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/file.h>

涉及到多进程操作时加入如下语句： 
#include <sys/wait.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <signal.h>

涉及到多线程操作时加入如下语句： 
#include <pthread.h>
#include <sys/poll.h>
需要注意的是，应该在编译时链接线程库，即增加编译选项：-lthread