Linux 网络编程 简单实例

一、编写Linux下socket协议TCP的ClientServer程序

//客户端,client:

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/stat.h>
#include<arpa/inet.h>
#define MAXBUF 256
int main()
{
    int ssock;
    int clen;
    struct sockaddr_in server_addr;
    char buf[MAXBUF];
    if((ssock=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP))<0){
        perror("socket error:");
        exit(1);
    }
    clen = sizeof(server_addr);
    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family     =AF_INET;
    server_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
    server_addr.sin_port       =htons(7758);
    if(connect(ssock,(struct sockaddr *)&server_addr,clen)<0){
        perror("connect error:");
        exit(1);
    }
    memset(buf,0,MAXBUF);
    if(read(ssock,buf,MAXBUF)<=0)
    {
        perror("read error:");
        exit(1);
    }
    close(ssock);
    printf("\nread: %s\n",buf);
    return 0;
}

//服务端,server:

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/stat.h>
#include<arpa/inet.h>
#define MAXBUF 256
int main()
{
    int clen;
    int ssock,csock;
    struct sockaddr_in client_addr,server_addr;
    char buf[MAXBUF];
    if((ssock=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP))<0){
        perror("socket error:");
        exit(1);
    }
    clen = sizeof(client_addr);
    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family     =AF_INET;
    server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
    server_addr.sin_port=htons(7758);
    if(bind(ssock,(struct sockaddr *)&server_addr,sizeof(server_addr))<0){
        perror("bind error");
        exit(1);
    }
    if(listen(ssock,8)<0){
        perror("listen error:");
        exit(1);
    }
    while(1){
        csock=accept(ssock,(struct sockaddr *)&client_addr,&clen);
        if(write(csock,buf, MAXBUF)<=0)
            perror("write error:");
        close(csock);
    }
    return 0;
}

二、编写Linux下的socket协议UDP Client/Server程序

//客户端,client:

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/stat.h>
#include<arpa/inet.h>
#define MAXBUF 256
int main()
{
    int ssock;
    int clen;
    struct sockaddr_in client_addr,server_addr;
    char buf[MAXBUF];
    strcpy(buf,"I miss you already!\n");
    if((ssock = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP))<0){
        perror("socket error:\n");
        exit(1);
    }
    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family  =AF_INET;
    server_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
    server_addr.sin_port=htons(7758);
    sendto(ssock,(void *)buf,MAXBUF,0,(struct sockaddr*)&server_addr,sizeof(server_addr));
    printf("Send message:%s\n",buf);
    clen=sizeof(client_addr);
    recvfrom(ssock,(void *)buf,MAXBUF,0,(struct sockaddr*)&server_addr,&clen);
    printf("Receive message:%s\n",buf);
    close(ssock);
    return 0;
}

//服务端,server:

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/stat.h>
#include<arpa/inet.h>
#define MAXBUF 256
int main()
{
    int ssock;
    int clen;
    struct sockaddr_in client_addr,server_addr;
    char buf[MAXBUF];
    if((ssock=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP))<0){
        perror("socket error:");
        exit(1);
    }
    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family=AF_INET;
    server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
    server_addr.sin_port=htons(7758);
    if(bind(ssock,(struct sockaddr *)&server_addr,sizeof(server_addr))<0){
        perror("bind error:");
        exit(1);
    }
    clen=sizeof(client_addr);
    recvfrom(ssock,(void *)buf,MAXBUF,0,(struct sockaddr*)&client_addr,&clen);
    strcpy(buf,"I miss you");
    sendto(ssock,(void *)buf,MAXBUF,0,(struct sockaddr*)&client_addr ,sizeof(client_addr));
    close(ssock);
    return 0;
}