系统编程—网络编程—多方消息收发

Posted 2021-06-04 是光哥呀

多方消息收发

基于 上文，加入fork函数创建子进程进行读写，可支持多客户端接入

服务端代码

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

int main(int argc,char **argv)
{
        int s_fd;
        int c_fd;
        int n_read;
        int mark=0;
        char readbuf[128];
        char msg[128]={0};

        struct sockaddr_in s_addr;
        struct sockaddr_in c_addr;

        if(argc!=3){
                printf("param is no good\\n");
                exit(-1);
        }

        memset(&s_addr,0,sizeof(struct sockaddr_in));
        memset(&c_addr,0,sizeof(struct sockaddr_in));

        //1.socket
        s_fd=socket(AF_INET,SOCK_STREAM,0);
        if(s_fd==-1){
                perror("socket");
                exit(-1);
        }
        //2.bind
        s_addr.sin_family =AF_INET;//英特尔网域
        s_addr.sin_port   =htons(atoi(argv[2]));//端口号 低于3000一般是操作系统用的 用户一般用5000-9000 htons()生成网络字节序
        inet_aton(argv[1],&s_addr.sin_addr);

        bind(s_fd,(struct sockaddr *)&s_addr,sizeof(struct sockaddr_in));

        //3.listen      
        listen(s_fd,10);//监听10个连接

        //4.accept
        int clen=sizeof(struct sockaddr_in);
        while(1){
                c_fd=accept(s_fd,(struct sockaddr *)&c_addr,&clen);
                if(c_fd==-1){
                        perror("accept");
                }
                mark++;
                printf("get connetc:%s\\n",inet_ntoa(c_addr.sin_addr));

                if(fork()==0){
                        if(fork()==0){
                                while(1){
                                        sprintf(msg,"welcom no.%d client\\n",mark);
                                        write(c_fd,msg,strlen(msg));
                                        sleep(3);
                                }
                        }

                        //5.read
                        while(1){
                                memset(readbuf,0,sizeof(readbuf));
                                n_read=read(c_fd,readbuf,128);
                                if(n_read==-1){
                                        perror("read");
                                }else{
                                        printf("get message:%d,%s\\n",n_read,readbuf);
                                }
                        }
                        break;
                }

        }

        return 0;
}                   

客户端代码

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

int main(int argc,char **argv)
{
        int c_fd;
        int n_read;
        char readbuf[128];
        char msg[128]={0};

        struct sockaddr_in c_addr;

        memset(&c_addr,0,sizeof(struct sockaddr_in));

        if(argc!=3){
                printf("param is no good\\n");
                exit(-1);
        }

        //1.socket
        c_fd=socket(AF_INET,SOCK_STREAM,0);
        if(c_fd==-1){
                perror("socket");
                exit(-1);
        }
        c_addr.sin_family =AF_INET;//英特尔网域
        c_addr.sin_port   =htons(atoi(argv[2]));//端口号 低于3000一般是操作系统用的 用户一般用5000-9000 htons()生成网络字节序
        inet_aton(argv[1],&c_addr.sin_addr);

        //2.connect
        if(connect(c_fd,(struct sockaddr *)&c_addr,sizeof(struct sockaddr))==-1){
                perror("connect");
                exit(-1);
        }

        while(1){
                if(fork()==0){
                        while(1){
                                memset(msg,0,sizeof(msg));
                                printf("input:\\n");
                                gets(msg);
                                write(c_fd,msg,strlen(msg));
                        }
                }

                while(1){
                        memset(readbuf,0,sizeof(readbuf));
                        n_read=read(c_fd,readbuf,128);
                        if(n_read==-1){
                                perror("read");
                        }else{
                                printf("get message from serve:%d,%s\\n",n_read,readbuf);
                        }
                }
        }

        return 0;
}

运行效果：可接入多个客户端，并显示第几个客户端，可发送消息至服务端