libevent 做UDP 服务器的例子源码

UDP server over libevent – sample code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <event.h>
#include <event2/listener.h>

#define SVR_IP "127.0.0.1"
#define SVR_PORT 10000
#define BUF_SIZE 1024

void read_cb(int fd, short event, void *arg) {
char buf[BUF_SIZE];
int len;
int size = sizeof(struct sockaddr);
struct sockaddr_in client_addr;

memset(buf, 0, sizeof(buf));
len = recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr *)&client_addr, &size);

if (len == -1) {
perror("recvfrom()");
} else if (len == 0) {
printf("Connection Closed\n");
} else {
printf("Read: len [%d] – content [%s]\n", len, buf);

/* Echo */
sendto(fd, buf, len, 0, (struct sockaddr *)&client_addr, size);
}
}

int bind_socket(struct event *ev) {
int sock_fd;
int flag = 1;
struct sockaddr_in sin;

/* Create endpoint */
if ((sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket()");
return -1;
}

/* Set socket option */
if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(int)) < 0) {
perror("setsockopt()");
return 1;
}

/* Set IP, port */
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = inet_addr(SVR_IP);
sin.sin_port = htons(SVR_PORT);

/* Bind */
if (bind(sock_fd, (struct sockaddr *)&sin, sizeof(struct sockaddr)) < 0) {
perror("bind()");
return -1;
} else {
printf("bind() success – [%s] [%u]\n", SVR_IP, SVR_PORT);
}

/* Init one event and add to active events */
event_set(ev, sock_fd, EV_READ | EV_PERSIST, &read_cb, NULL);
if (event_add(ev, NULL) == -1) {
printf("event_add() failed\n");
}

return 0;
}

int main(void) {
struct event ev;

/* Init. event */
if (event_init() == NULL) {
printf("event_init() failed\n");
return -1;
}

/* Bind socket */
if (bind_socket(&ev) != 0) {
printf("bind_socket() failed\n");
return -1;
}

/* Enter event loop */
event_dispatch();

return 0;
}