2022-4-19 同时读取带外数据和正常数据《Linux高性能服务器》笔记

服务端

#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<assert.h>
#include<stdio.h>
#include<unistd.h>
#include<errno.h>
#include<string.h>
#include<fcntl.h>
#include<stdlib.h>
int main(void){
    
    
    int ret = 0;
    struct sockaddr_in address;
    bzero(&address,sizeof(address));
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(9999);

    int listenfd = socket(AF_INET,SOCK_STREAM,0);
    if(listenfd == -1){
    
    
        perror("socket");
        return -1;
    }
    ret = bind(listenfd,(struct sockaddr*)&address,sizeof(address));
    if(ret == -1){
    
    
        perror("bind");
        return -1;
    }
    ret = listen(listenfd,5);
    if(ret == -1){
    
    
        perror("listen");
        return -1;
    }
    struct sockaddr_in client_address;
    socklen_t client_addrlength = sizeof(client_address);
    int connfd = accept(listenfd,(struct sockaddr*)&client_address,&client_addrlength);
    if(connfd == -1){
    
    
        perror("connect");
        close(listenfd);
    }
    char buf[1024];
    fd_set read_fds;
    fd_set exception_fds;
    FD_ZERO(&read_fds);
    FD_ZERO(&exception_fds);
    while(1){
    
    
        memset(buf,'\0',sizeof(buf));
        FD_SET(connfd,&read_fds);
        FD_SET(connfd,&exception_fds);
        ret = select(connfd+1,&read_fds,NULL,&exception_fds,NULL);
        if(ret == -1){
    
    
            perror("select");
            break;
        }
        if(FD_ISSET(connfd,&read_fds)){
    
    
            ret = recv(connfd,buf,sizeof(buf)-1,0);
            if(ret == -1){
    
    
                perror("recv1");
                break;
            }
            printf("get %d bytes of normal data :%s \n",ret,buf);
        }else if(FD_ISSET(connfd,&exception_fds)){
    
    
        //对于同一个连接这里加了else带外数据读不出来
        //或许对于不同的连接，带外数据或者读的出来
            ret = recv(connfd,buf,sizeof(buf)-1,MSG_OOB);
            if(ret == -1){
    
    
                perror("recv2");
                break;
            }
            printf("get %d bytes of oob data :%s \n",ret,buf);
        }
    }
    close(connfd);
    close(listenfd);
    
    return 0;
}

客户端

#include<stdio.h>
#include<arpa/inet.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>

int main(void){
    
    
    //1.创建套接字
    int fd = socket(AF_INET,SOCK_STREAM,0);
    if(fd == -1){
    
    
        perror("socket");
        exit(0);
    }

    //2.连接服务器端
    struct sockaddr_in serveraddr;
    serveraddr.sin_family = AF_INET;
    inet_pton(AF_INET,"192.168.131.138",&serveraddr.sin_addr.s_addr);
    serveraddr.sin_port = htons(9999);
    int ret = connect(fd,(struct sockaddr*)&serveraddr,sizeof(serveraddr));
    if(ret == -1){
    
    
        perror("connect");
        exit(0);
    }

    //3.通信
    const char*oob_data = "abc";
    const char*normal_data = "123";
    send(fd,normal_data,strlen(normal_data),0);
    send(fd,oob_data,strlen(oob_data),MSG_OOB);
    send(fd,normal_data,strlen(normal_data),0);

    close(fd);
    getchar();
    return 0;
}

服务端程序运行结果