epoll实现echo服务器

epoll实现echo服务器

运行效果

代码实现

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <unistd.h>
#include <sys/poll.h>
#include <sys/epoll.h>

#define MAX_CLI 50

int clients[MAX_CLI];
struct sockaddr_in clientaddr;
socklen_t len = sizeof(clientaddr);


void print_error(const char *msg) {
    perror(msg);
    exit(EXIT_FAILURE);
}

int socket_create(int port) {//创建并绑定网络监听的socket套接字
    int fd;
    if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("socket");
        exit(EXIT_FAILURE);
    }
    struct sockaddr_in addr;
    bzero(&addr, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = htons(port);
    if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        perror("bind");
        exit(EXIT_FAILURE);
    }
    if (listen(fd, 20) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    return fd;
}
int recv_msg(int fd, char *buff, int size) { 

    int rsize = recv(fd, buff, sizeof(char ) * size, 0);
    if (rsize <= 0) {
        if (rsize == 0) return 0;
        return -1;
    }
    printf("Recv : %s\n", buff);
    return 1;
}

int send_msg(int fd, char *buff, int size) {
    int ssize = send(fd, buff, sizeof(char ) * size, 0);
    if (ssize <= 0) {
        if (ssize == 0) return 0;
        return -1;
    }
    printf("Send success!\n");
    return 1;
}

void echo_work(int server_listen) {
    int epollfd  = epoll_create(1);//创建epoll实例
    if (epollfd < 0)  
        print_error("epoll_create");
    
    struct epoll_event event, events[MAX_CLI];
    event.events = EPOLLIN;
    event.data.fd = server_listen;//将server_listen添加到epoll实例中
    
    if (epoll_ctl(epollfd, EPOLL_CTL_ADD, server_listen, &event) < 0) 
        print_error("epoll_ctl");
    
    while (1) {
        int num_events = epoll_wait(epollfd, events, MAX_CLI, -1);//等待事件发生
        
        if (num_events < 0) 
            print_error("epoll_wait");

        for (int i = 0; i < num_events; i++) {
            if (events[i].data.fd == server_listen) {
                int cli_fd = accept(server_listen, (struct sockaddr*)&clientaddr, &len);
                if (cli_fd < 0) 
                    print_error("accept");
                printf("new connection success\n");

                //将客户端添加到epoll实例中去
                event.events = EPOLLIN;
                event.data.fd = cli_fd;

                if (epoll_ctl(epollfd, EPOLL_CTL_ADD, cli_fd, &event) < 0) 
                    perror("epoll_ctl");

            } else {
                //接收消息，回复消息
                int cli_fd = events[i].data.fd;
                char buff[1024] = {0};
                int ret;

                if ((ret = recv_msg(cli_fd, buff, 1024)) <= 0) {
                    ret == 0 ? printf("连接中断\n") : printf("客户端异常\n");
                    if (epoll_ctl(epollfd, EPOLL_CTL_DEL, cli_fd, NULL) < 0) 
                        print_error("epoll_ctl");
                    close(cli_fd);
                    continue;
                }
                    
                    send_msg(cli_fd, buff, strlen(buff));//回显数据
                }
        }
    }
    return ;
}


int main() {
    int server_listen;

    if ((server_listen = socket_create(8080)) < 0) {
        perror("socket_create");
        exit(EXIT_FAILURE);
    }
    for(int i = 0; i < MAX_CLI; i++) clients[i] = -1;
    echo_work(server_listen);

    return 0;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132