长生栈
DC Wang
2022-03-25
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C linux socket - tcp - epoll

# C linux socket - tcp - select

# 封装原始socket库

  • myconnect.h
#ifndef __MYCONNECT_H_
#define __MYCONNECT_H_

#include<sys/socket.h>

int Accept(int __fd, struct sockaddr *__restrict__ __addr, socklen_t *__restrict__ __addr_len);
int Bind(int __fd, const struct sockaddr *__addr, socklen_t __len);
int Connect(int __fd, const struct sockaddr *__addr, socklen_t __len);
int Listen(int __fd, int __n);
int Socket(int __domain, int __type, int __protocol);
ssize_t Read(int __fd, void *__buf, size_t __nbytes);
ssize_t Write(int __fd, const void *__buf, size_t __n);
int Close(int __fd);

ssize_t Readn(int __fd, void *__buf, size_t n);
ssize_t Writen(int __fd, const void *__buf, size_t n);
ssize_t Readline(int __fd, void *__buf, size_t maxlen);

#endif
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  • myconnect.c
#include"myconnect.h"
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<errno.h>
#include<sys/socket.h>

#define handle_error(msg) \
           do { perror(msg); exit(EXIT_FAILURE); } while (0)

int Accept(int __fd, struct sockaddr *__restrict__ __addr, socklen_t *__restrict__ __addr_len)
{
    int n;
again:
    if ((n = accept(__fd, __addr, __addr_len)) < 0)
        if((errno==ECONNABORTED)||(errno==EINTR))
            goto again;
        else
            handle_error("accept");
    return n;
}

int Bind(int __fd, const struct sockaddr *__addr, socklen_t __len)
{
    int n;
    if ((n = bind(__fd, __addr, __len)) < 0)
        handle_error("bind");
    return n;
}

int Connect(int __fd, const struct sockaddr *__addr, socklen_t __len)
{
    int n;
    ;
    if ((n = connect(__fd, __addr, __len)) < 0)
        handle_error("connect");
    return n;
}

int Listen(int __fd, int __n)
{
    int n;
    if ((n = listen(__fd, __n)) < 0)
        handle_error("listen");
    return n;
}

int Socket(int __domain, int __type, int __protocol)
{
    int n;
    if ((n = socket(__domain, __type, __protocol)) < 0)
        handle_error("socket");
    return n;
}

/**
 * read返回值：
 *      1.> 0 实际读到的字节数
 *      2.= 0 数据读完（读到文件末尾、管道写端关闭、socket对端关闭）
 *      3.-1  异常
 *              1.errno==EINTR  被信号中断  重启/退出
 *              2.errno==EAGAIN（EWOULDBLOCK）  非阻塞方式读，并且没有数据
 *              3.其他情况  错误。---perror；  exit；
*/
ssize_t Read(int __fd, void *__buf, size_t __nbytes)
{
    ssize_t n;
again:
    if ((n = read(__fd, __buf, __nbytes)) == -1)
        if (errno == EINTR)
            goto again;
        else
            return -1;
    return n;
}

ssize_t Write(int __fd, const void *__buf, size_t __n)
{
    ssize_t n;
again:
    if((n=write(__fd,__buf,__n))==-1)
        if(errno==EINTR)
            goto again;
        else
            return -1;
    return n;
}

int Close(int __fd)
{
    int n;
    if((n=close(__fd))==-1)
        handle_error("close");
    return n;
}

/**
 * 读一定数量字符串，成功返回0，失败返回非零。
 * size_t n:应该读取的字节数
*/
ssize_t Readn(int __fd, void *__buf, size_t n)
{
    size_t nleft;           //unsigned int 剩余未读取的字节数
    ssize_t nread;          //int 实际读到的字节数
    char *ptr;

    ptr = __buf;
    nleft = n;              //n 未读取字节数
    while (nleft > 0)
    {
        if ((nread = read(__fd, ptr, nleft)) < 0)
        {
            if (errno == EINTR)
                nread = 0;
            else
                return -1;
        }
        else if (nread == 0)
            break;

        nleft -= nread;
        ptr += nread;
    }
    return n - nleft;
}

/*写一定数量字符串，成功返回0，失败返回-1或大于0的数*/
ssize_t Writen(int __fd, const void *__buf, size_t n)
{
    size_t nleft;
    ssize_t nwritten;
    const char *ptr = __buf;
    nleft = n;
    while (nleft > 0)
    {
        if((nwritten = write(__fd, ptr, nleft))<0)
        {
            if (errno == EINTR)
                nwritten = 0;
            else
                return -1;
        }
        else if (nwritten == 0)
            break;
        nleft -= nwritten;
        ptr += nwritten;
    }
    return nleft;
}

/*供Readline()使用*/
static ssize_t my_read(int __fd,char*ptr)
{
    static int read_cnt;
    static char *read_ptr;
    static char read_buff[100];

    if (read_cnt <= 0)
    {
again:
        if ((read_cnt = read(__fd, read_buff, sizeof(read_buff))) < 0)
        {
            if(errno==EINTR)
                goto again;
            return -1;
        }
        else if(read_cnt==0)
            return 0;

        read_ptr = read_buff;
    }
    read_cnt--;
    *ptr = *read_ptr++;

    return 1;
}
/*调用my_read(),实现一次读一行，即读到\n结束，末尾\n\0。*/
ssize_t Readline(int __fd, void *__buf, size_t maxlen)
{
    ssize_t n, rc;
    char    c, *ptr;
    ptr = __buf;

    for (n = 1; n < maxlen; n++)
    {
        if ((rc = my_read(__fd, &c)) == 1)
        {
            *ptr++ = c;
            if(c=='\n')
                break;
        }
        else if(rc==0)
        {
            *ptr = 0;
            return n - 1;
        }else
            return -1;
    }
    *ptr = 0;
    return n;
}
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# 调用-client

  • client.c
#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<ctype.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<string.h>
#include"myconnect.h"

#define SERV_PORT 6868
#define SERV_IP "192.168211.129"

int main()
{
    int cfd;
    struct sockaddr_in serv_addr;
    char buf[BUFSIZ];
    cfd = Socket(AF_INET, SOCK_STREAM, 0);

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERV_PORT);
    inet_pton(AF_INET, SERV_IP, &serv_addr.sin_addr.s_addr);

    Connect(cfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
    while(1)
    {
        memset(buf, 0, sizeof(buf));
        fgets(buf, sizeof(buf), stdin);
        Write(cfd, buf, strlen(buf));
        int n=Read(cfd, buf, sizeof(buf));
        if (n > 0)
            printf("%s", buf);
        else
            break;
    }

    close(cfd);

    return 0;
}
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# 调用-server

  • server.c
#include<stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<sys/epoll.h>
#include<netinet/in.h>
#include<stdlib.h>
#include<errno.h>
#include <arpa/inet.h>
#include<unistd.h>
#include<ctype.h>
#include"myconnect.h"
#include<string.h>
#include<time.h>

#define SERV_PORT  6868
#define OPEN_MAX   5000



int main()
{
    int lfd, cfd, sockfd, i, n, num = 0;                /*listenfd connectfd*/
    ssize_t nready, efd, res;
    char clie_ip[INET_ADDRSTRLEN], buf[BUFSIZ];         /*客户端IP、传输字符串*/
    struct sockaddr_in serv_addr, clie_addr;
    socklen_t clie_addr_len;
    struct epoll_event tep, ep[OPEN_MAX];               /*tep:epoll_ctl参数 ep[]:epoll_wait参数*/    


    lfd = Socket(AF_INET, SOCK_STREAM, 0);
    int opt = 1;
    setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));   /*端口复用*/

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERV_PORT);
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    Bind(lfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
    Listen(lfd, 10);

    efd = epoll_create(OPEN_MAX);                       /*创建epoll模型，efd为红黑树根节点*/ 
    if(efd==-1)
    {
        perror("epoll_create");
        exit(1);
    }

    tep.events = EPOLLIN;
    tep.data.fd = lfd;
    res = epoll_ctl(efd, EPOLL_CTL_ADD, lfd, &tep);     /*将lfd及对应结构体设置到树上*/
    if(res==-1)
    {
        perror("epoll_ctl");
        exit(1);
    }
    while(1)
    {
        /*epoll为server阻塞监听事件，ep为struct epoll_event类型数组，OPEN_MAX为数组容量，-1表永久阻塞*/
        nready = epoll_wait(efd, ep, OPEN_MAX, -1);
        if(nready==-1)
        {
            perror("epoll_wait");
            exit(0);
        }
        for (i = 0; i < nready; i++)                   
        {
            if (!(ep[i].events & EPOLLIN))                   /*如果不是读事件继续循环*/
                continue;

            if (ep[i].data.fd == lfd)                       /*满足的是lfd*/
            {
                printf("lfd %d\n", lfd);
                clie_addr_len = sizeof(clie_addr);
                cfd = Accept(lfd, (struct sockaddr *)&clie_addr, &clie_addr_len);    

                printf("New Client, IP:%s,PORT:%d\n", inet_ntop(AF_INET, &clie_addr.sin_addr.s_addr,
                clie_ip, sizeof(clie_ip)), ntohs(clie_addr.sin_port));
                printf("cfd %d---client %d\n", cfd, ++num);

                tep.events = EPOLLIN;
                tep.data.fd = cfd;
                res = epoll_ctl(efd, EPOLL_CTL_ADD, cfd, &tep);
                if(res==-1)
                {
                    perror("cfd epoll_ctl");
                    exit(1);
                }
            }
            else
            {
                sockfd = ep[i].data.fd;
                memset(buf, 0, sizeof(buf));
                if ((n = Read(sockfd, buf, sizeof(buf))) == 0)
                {
                    res = epoll_ctl(efd, EPOLL_CTL_DEL, sockfd, NULL);
                    if(res==-1)
                    {
                        perror("epoll_ctl");
                        exit(1);
                    }
                    Close(sockfd);
                    printf("client[%d] closed connection\n", sockfd);
                }
                else if(n<0)
                {
                    perror("read n<0 error:");
                    res = epoll_ctl(efd, EPOLL_CTL_DEL, sockfd, NULL);
                    if(res==-1)
                    {
                        perror("epoll_ctl");
                        exit(1);
                    }
                    Close(sockfd);
                }
                else if(n>0)
                {
                    printf("%d 个字符已读入：%s", n, buf);
                    for (i = 0; i < n; i++)
                    {
                        buf[i] = toupper(buf[i]);
                    }
                        //sleep(10);
                    Write(sockfd, buf, n);
                }
            }

        }
            
    }

    Close(lfd);
    Close(efd);
    return 0;
}
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# makefile

  • makefile
all: server client
server: server.c myconnect.o
	gcc server.c myconnect.o -o server
client: client.c myconnect.o
	gcc client.c myconnect.o -o client
myconnect.o:myconnect.c
	gcc -c myconnect.c
clean:
	rm *.o server client
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# 编译

#编译
make
#清除编译文件
#make clean
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先执行server，再执行client，效果是client输入小写，server转大写后发送回client。

编辑 (opens new window)
#C#socket
上次更新: 2023/03/31, 22:34:04
C linux socket - tcp - select
C linux socket - tcp - 线程池epoll

← C linux socket - tcp - 线程池epoll→

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