C采用多线程和多进程实现TCP/UDP网络连接

淩亂°似流年 2022-12-11 05:25 107阅读 0赞

### 文章目录 ###

*  基础版
 *  多进程版本
 *  多线程版本
 *  UDP实现

# 基础版 #

封装的socket.h  
**warp\_socket.h**

#ifndef _WRAP__
    #define _WRAP__
    
    #include <sys/socket.h>
    
    int check(int ret, char *str);
    
    int my_socket(int domain, int type, int protocol);
    
    int default_my_socket_ipv4_tcp();
    
    struct sockaddr_in* create_ipv4_for_localhost(struct sockaddr_in *srv_addr, uint16_t port);
    
    
    int my_bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
    
    int my_listen(int sockfd, int backlog);
    
    int my_accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
    
    int my_connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
    
    ssize_t my_read(int fd, void *buf, size_t count);
    
    ssize_t my_write(int fd, const void *buf, size_t count);
    int my_setsockopt(int sockfd);
    #endif

**warp\_socket.c**

#include <stdio.h>
    #include <sys/socket.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <ctype.h>
    #include <arpa/inet.h>
    #include <errno.h>
    #include <strings.h>
    
    #define  SOCKET_ERROR "socket error"
    #define  CONNECT_ERROR "connect error"
    #define  LISTEN_ERROR "listen error"
    #define  BIND_ERROR "bind error"
    #define  ACCEPT_ERROR "accept error"
    #define  PORT_ERROR "port error"
    
    int check(int ret, char *str) {
        
        if (ret == -1) {
        
            perror(str);
            exit(EXIT_FAILURE);
        }
        return ret;
    }
    
    int my_socket(int domain, int type, int protocol) {
        
        return check(socket(domain, type, protocol), SOCKET_ERROR);
    }
    
    int default_my_socket_ipv4_tcp() {
        
        return my_socket(AF_INET, SOCK_STREAM, 0);
    }
    
    struct sockaddr_in *create_ipv4_for_localhost(struct sockaddr_in *srv_addr, uint16_t port) {
        
        //将地址结构清零
    //    memset(&srv_addr,0, sizeof(srv_addr));
        bzero(srv_addr, sizeof(srv_addr));
        srv_addr->sin_family = AF_INET;
        srv_addr->sin_port = htons(port);
        srv_addr->sin_addr.s_addr = htonl(INADDR_ANY);
        return srv_addr;
    }
    
    int my_bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
        
        return check(bind(sockfd, addr, addrlen), BIND_ERROR);
    }
    
    int my_listen(int sockfd, int backlog) {
        
        return check(listen(sockfd, backlog), LISTEN_ERROR);
    }
    
    int my_accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen) {
        
        int i;
        again :
        if ((i = accept(sockfd, addr, addrlen)) < 0) {
        
            //因为accept是个慢系统调用,发送信号后中断后,重试.
            /**      EINTR:如果进程在一个慢系统调用(slow system call)中阻塞时，
                    当捕获到某个信号且相应信号处理函数返回时，
                    这个系统调用被中断，调用返回错误，
                    设置errno为EINTR
                */
    
            /**
             * ECONNABORTED
             *  该错误被描述为“software caused connection abort”，即“软件引起的连接中止”。
             *  原因在于当服务和客户进程在完成用于 TCP 连接的“三次握手”后，
             *  客户 TCP 却发送了一个 RST （复位）分节，在服务进程看来，就在该连接已由 TCP 排队，
             *  等着服务进程调用 accept 的时候 RST 却到达了。POSIX 规定此时的 errno 值必须 ECONNABORTED。
             *  源自 Berkeley 的实现完全在内核中处理中止的连接，
             *  服务进程将永远不知道该中止的发生。服务器进程一般可以忽略该错误，直接再次调用accept。
             */
            if ((errno == ECONNABORTED) || (errno == EINTR)) {
        
                //重试等待连接
                goto again;
            } else {
        
                return check(i, ACCEPT_ERROR);
            }
        }
    
    }
    
    int my_connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
        
        return check(connect(sockfd, addr, addrlen), CONNECT_ERROR);
    }
    
    ssize_t my_read(int fd, void *buf, size_t count) {
        
        ssize_t i;
        again :
        if ((i = read(fd, buf, count)) < 0) {
        
            if (errno == EINTR) {
        
                goto again;
            } else {
        
                return -1;
            }
        }
        return i;
    }
    
    /**
     * 重复读取count个数数据
     *
     * @param fd
     * @param buf
     * @param count 读取指定个数,应该<=buf空间
     * @return
     */
    ssize_t my_readn(int fd, void *buf, size_t count) {
        
        ssize_t i;
        //记录剩余尚未读取个数
        ssize_t nleft = count;
        char *ptr = buf;
        while (nleft > 0) {
        
            if ((i = read(fd, buf, nleft)) < 0) {
        
                if (errno == EINTR) {
        
                    i = 0;
                } else {
        
                    return -1;
                }
            } else if (i == 0) {
        
                break;
            }
            //说明读取成功
            //重新计算应读个数,以及指针偏移
            nleft -= i;
            ptr += i;
        }
        //返回已读个数
        return count - nleft;
    }
    
    ssize_t my_writen(int fd, void *buf, size_t count) {
        
        ssize_t i;
        ssize_t nleft = count;
        char *ptr = buf;
        while (nleft > 0) {
        
            if ((i = write(fd, buf, nleft)) <= 0) {
        
                if (i < 0 && errno == EINTR) {
        
                    i = 0;
                } else {
        
                    return -1;
                }
            }
            nleft -= i;
            ptr += i;
        }
        //返回已写个数
        return count - nleft;
    }
    
    ssize_t my_write(int fd, const void *buf, size_t count) {
        
        ssize_t i;
        again :
        if ((i = write(fd, buf, count)) < 0) {
        
            if (errno == EINTR) {
        
                goto again;
            } else {
        
                return -1;
            }
        }
        return i;
    }
    
    /**
    * 设置端口复用,也就是可以重复利用同一个端口运行服务器
    */
    int my_setsockopt(int sockfd) {
        
        //是否启用,0不启用
        int opt = 1;
        return check(setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (void *) &opt, sizeof(opt)), PORT_ERROR);
    }

**客户端**

#include <stdio.h>
    #include <sys/socket.h>
    #include <unistd.h>
    #include <arpa/inet.h>
    #include  "warp_socket.h"
    #define  PORT 8080
    
    int main() {
        
        char buf[BUFSIZ];
    
        struct sockaddr_in serv_addr;
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_port = htons(PORT);
    //    inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr.s_addr);
        inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);
    
        int cfd = default_my_socket_ipv4_tcp();
    
    
        int ret = my_connect(cfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
    
        while (1) {
        
            my_write(cfd, "hello\n", 6);
            sleep(1);
            int size = my_read(cfd, buf, sizeof(buf));
            my_write(STDOUT_FILENO, buf, size);
        }
        close(cfd);
        return 0;
    }

**服务端**

#include <stdio.h>
    #include <sys/socket.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <ctype.h>
    #include <arpa/inet.h>
    #include  "warp_socket.h"
    
    /**
     * 一个文件描述符指向一个套接字,该套接字内部由内核借助2个缓冲区实现
     *
     * 网络字节序
     *          小端存储法(pc本地存储):高位存高地址,低位存低地址.
     *          大端存储法(网络存储):同上相反.
     *          h表示host，n表示network，l表示32位整数,s表示16位短整数
     *          htonl：本地 => 网络(IP)      只接收32位整数,所以需要先将点分十进制形式(192.XX.XX.XX)的ip地址转成整数, INADDR_ANY获取系统有效IP地址,32整型
     *          htons：本地 => 网络(port)
     *          ntohl  网络 => 本地(IP)
     *          ntohs  网络 => 本地(port)
     *
     * IP地址转换
     *          int inet_pton(int af, const char *src, void *dst);      本地(string) =>网络
     *          af : AF_INET / AF_INET6  ipv4 /ipv6
     *          src : IP地址(点分10进制形式)
     *          dst : 传出参数,网络字节序的ip地址
     *
     *          const char *inet_ntop(int af, const void *src,char *dst, socklen_t size);  网络 => 本地(string)
     */
    
    #define  PORT 8080
    
    int main() {
        
        int lfd, cfd;
        int ret;
        char buf[BUFSIZ], cli_Ip[1024];
        struct sockaddr_in serv_addr, clit_addr;
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_port = htons(PORT);
        serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    
        /**
         * int socket(int domain, int type, int protocol);
         * domain : ip地址协议
         * type : 数据协议 流式协议,报式协议
         * protocol ： 选用协议的代表协议. 流式就是tcp,报式就是udp
         */
    
        lfd = default_my_socket_ipv4_tcp();
    
        /**
         *  int bind(int sockfd, const struct sockaddr *addr,socklen_t addrlen);
         *  struct sockaddr_in {
                sa_family_t sin_family;  IP地址协议
                in_port_t sin_port;  端口(网络字节序)
                struct in_addr sin_addr;  ip(网络字节序)
            }
            sockaddr_in主要弥补sockaddr的缺陷(目标地址和端口信息混在一起),占用字节大小都一样.
         */
        my_bind(lfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
        //最多允许连接数
        my_listen(lfd, 128);
    
        //监听并处理连接
        socklen_t client_addr_len = sizeof(clit_addr);
        cfd = my_accept(lfd, (struct sockaddr *) &clit_addr, &client_addr_len);
    
        printf("client ip: %s , port: %d  \n", inet_ntop(AF_INET, &clit_addr.sin_addr.s_addr, cli_Ip, sizeof(cli_Ip)),
               ntohs(clit_addr.sin_port)
        );
        while (1) {
        
            ret = my_read(cfd, buf, sizeof(buf));
            my_write(STDOUT_FILENO, buf, ret);
            for (int i = 0; i < ret; ++i) {
        
                buf[i] = toupper(buf[i]);
            }
            my_write(cfd, buf, ret);
        }
        close(cfd);
        close(lfd);
    
        return 0;
    }

# 多进程版本 #

#include <stdio.h>
    #include <sys/socket.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <ctype.h>
    #include <arpa/inet.h>
    #include <signal.h>
    #include <wait.h>
    #include  "warp_socket.h"
    
    /**
     * 多进程
     * @return
     */
    #define PORT 8080
    
    void killP() {
        
        while (waitpid(0, NULL, WNOHANG) > 0);
        return;
    }
    
    int main() {
        
        int lfd, cfd;
        int ret;
        char buf[BUFSIZ];
        pid_t pid;
        struct sockaddr_in srv_addr, cli_addr;
        create_ipv4_for_localhost(&srv_addr, PORT);
    
        lfd = default_my_socket_ipv4_tcp();
        my_bind(lfd, (struct sockaddr *) &srv_addr, sizeof(srv_addr));
        my_listen(lfd, 128);
    
        socklen_t cli_addr_len = sizeof(cli_addr);
        while (1) {
        
            cfd = my_accept(lfd, (struct sockaddr *) &cli_addr, &cli_addr_len);
            pid = fork();
            if (pid < 0) {
        
                exit(EXIT_FAILURE);
            } else if (pid == 0) {
        
                //关闭主进程accept描述符
                close(lfd);
                break;
            } else {
        
                //关闭子进程描述符
                close(cfd);
                //回收子进程
                struct sigaction act;
                act.sa_handler = killP;
                sigemptyset(&act.sa_mask);
                act.sa_flags = 0;
                ret = sigaction(SIGCHLD, &act, NULL);
                if (ret != 0) {
        
                    perror("error");
                    exit(EXIT_FAILURE);
                }
                continue;
            }
        }
        if (pid == 0) {
        
            while (1) {
        
                ret = my_read(cfd, buf, sizeof(buf));
                printf("%d \n", ret);
                //读到文件末尾或者客户端主动断开,则直接返回
                if (ret <= 0) {
        
                    close(cfd);
                    perror("error");
                    exit(EXIT_FAILURE);
                }
                my_write(STDOUT_FILENO, buf, ret);
                for (int i = 0; i < ret; i++) {
        
                    buf[i] = toupper(buf[i]);
                }
                my_write(cfd, buf, ret);
            }
        }
    
        return 0;
    }

# 多线程版本 #

#include <stdio.h>
    #include <sys/socket.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <ctype.h>
    #include <arpa/inet.h>
    #include <signal.h>
    #include <wait.h>
    #include <pthread.h>
    #include  "warp_socket.h"
    
    /**
     * 多线程
     * @return
     */
    #define PORT 8080
    struct s_info {
        
        struct sockaddr_in cliaddr;
        int fd;
    };
    
    void *work_fun(void *s_info) {
        
        struct s_info *s = (struct s_info *) s_info;
        int ret;
        char buf[BUFSIZ];
        char str[INET_ADDRSTRLEN];
        while (1) {
        
            ret = my_read(s->fd, buf, BUFSIZ);
            printf("%d \n", ret);
            //读到文件末尾或者客户端主动断开,则直接返回
            if (ret <= 0) {
        
                break;
            }
    
            printf("received from %s at PORT %d \n", inet_ntop(AF_INET, &(*s).cliaddr.sin_addr, str, INET_ADDRSTRLEN),
                   ntohs((*s).cliaddr.sin_port));
            printf("received from %s at PORT %d \n", inet_ntop(AF_INET, &(s->cliaddr.sin_addr), str, INET_ADDRSTRLEN),
                   ntohs(s->cliaddr.sin_port));
            my_write(STDOUT_FILENO, buf, ret);
            for (int i = 0; i < ret; i++) {
        
                buf[i] = toupper(buf[i]);
            }
            my_write(s->fd, buf, ret);
        }
        close(s->fd);
        return (void *) 0;
    }
    
    int main() {
        
        int lfd, cfd;
        int i = 0;
    
        struct sockaddr_in srv_addr, cli_addr;
        socklen_t cli_addr_len = sizeof(cli_addr);
        struct s_info t[256];
    
        create_ipv4_for_localhost(&srv_addr, PORT);
    
        lfd = default_my_socket_ipv4_tcp();
        my_bind(lfd, (struct sockaddr *) &srv_addr, sizeof(srv_addr));
        my_listen(lfd, 128);
        pthread_t tid;
        printf("wait for Accept... ");
        while (1) {
        
            cfd = my_accept(lfd, (struct sockaddr *) &cli_addr, &cli_addr_len);
            t[i].cliaddr = cli_addr;
            t[i].fd = cfd;
            pthread_create(&tid, NULL, work_fun, (void *) &t[i]);
            //线程分离,防止僵尸线程产生.
            pthread_detach(tid);
            i = (++i) % 256;
        }
        return 0;
    }

# UDP实现 #

**client.c**

#include <stdio.h>
    #include <sys/socket.h>
    #include <unistd.h>
    #include <arpa/inet.h>
    #include <strings.h>
    
    #define  PORT 8080
    
    int main() {
        
        char buf[BUFSIZ];
        int cfd;
        int n;
        struct sockaddr_in serv_addr;
        socklen_t serv_addr_len = sizeof(serv_addr);
    
        bzero(&serv_addr, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_port = htons(PORT);
        inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);
    
        cfd = socket(AF_INET, SOCK_DGRAM, 0);
    
        while (1) {
        
            //相当于connect+write
            n = sendto(cfd, "hello\n", 6, 0, (struct sockaddr *) &serv_addr, serv_addr_len);
            if (n == -1) {
        
                perror("error");
            }
            n = recvfrom(cfd, buf, BUFSIZ, 0, NULL, 0);  //不需要服务器的信息
            write(STDOUT_FILENO, buf, n);
            if (n == -1) {
        
                perror("error");
            }
            sleep(1);
        }
        close(cfd);
        return 0;
    }

**server.c**

#include <stdio.h>
    #include <sys/socket.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <ctype.h>
    #include <arpa/inet.h>
    #include <strings.h>
    
    /**
     * upd 通信
     * @return
     */
    #define PORT 8080
    int main() {
        
        int lfd;
        int n;
        char buf[BUFSIZ], cli_Ip[1024];
        struct sockaddr_in serv_addr, clit_addr;
        socklen_t client_addr_len = sizeof(clit_addr);
    
        lfd=socket(AF_INET, SOCK_DGRAM, 0);
    
        bzero(&serv_addr, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_port = htons(PORT);
        serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
        bind(lfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
    
        printf("acepting...");
        while (1){
        
            //相当于accpet+write
            n = recvfrom(lfd, buf,BUFSIZ,0,(struct sockaddr *)&clit_addr,&client_addr_len);
            if (n==-1){
        
                perror("error");
            }
            write(STDOUT_FILENO, buf, n);
            printf("client ip: %s , port: %d  \n", inet_ntop(AF_INET, &clit_addr.sin_addr.s_addr, cli_Ip, sizeof(cli_Ip)),
                   ntohs(clit_addr.sin_port));
            for (int i = 0; i < n; ++i) {
        
                buf[i] = toupper(buf[i]);
            }
            n=sendto(lfd, buf, n,0,(struct sockaddr *)&clit_addr, sizeof(clit_addr));
            if (n==-1){
        
                perror("error");
            }
        }
        close(lfd);
        return 0;
    }