无法接收数据 - 使用epoll的多个UDP套接字 [英] Multiple UDP sockets using epoll - Not able to receive data
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问题描述
我试着去接受使用epoll的多个UDP套接字的数据。这是一个测试程序,它没有插座的确切数字。(用于测试目的,其设定为50)下面的程序不会收到任何数据,并将其卡在epoll_wait(),因为我已经给它-1等待indefinetly直到它获取数据。但没有得到任何。
的#include<&stdio.h中GT;
#包括LT&;&stdlib.h中GT;
#包括LT&;&string.h中GT;
#包括LT&;&unistd.h中GT;
#包括LT&; SYS / types.h中>
#包括LT&; SYS / socket.h中>
#包括LT&; netinet / in.h中>
#包括LT&; ARPA / inet.h>
#包括LT&; SYS / epoll.h>
#包括LT&;&fcntl.h GT;的#define MAX_CON(50)
typedef结构UDPMessage
{
无符号短HDR;
无符号短CC1;
无符号短CC2;
unsigned char型数据[1472];
无符号短CC3;
} UDPPacket;静态结构epoll_event *事件;
诠释create_sockets(unsigned int类型端口);诠释create_sockets(unsigned int类型端口)
{
INT袜子,标志= 1;
结构SOCKADDR_IN sock_name; / *创建一个数据报套接字* /
袜子=插座(PF_INET,SOCK_DGRAM,0);
/ *套接字设置为非阻塞* /
的fcntl(袜子,F_SETFL,O_NONBLOCK); 如果(袜子℃,)
{
PERROR(插座);
出口(EXIT_FAILURE);
}
/ *设置重用标志。 * /
如果(setsockopt的(袜子,SOL_SOCKET,SO_REUSEADDR,&安培;标志的sizeof(标志))小于0)
{
PERROR(setsockopt的(SOL_SOCKET,SO_REUSEADDR));
出口(EXIT_FAILURE);
}
/ *给套接字的名称。 * /
sock_name.sin_family = AF_INET;
sock_name.sin_port = htons(端口);
sock_name.sin_addr.s_addr = htonl(INADDR_ANY);
如果(绑定(袜子,(结构sockaddr *)及sock_name,sizeof的(sock_name))小于0)
{
PERROR(绑定);
出口(EXIT_FAILURE);
}
返回袜子;
}INT主(INT ARGC,CHAR *的argv [])
{
FD_SET掌握;
FD_SET read_fds;
结构SOCKADDR_IN serveraddr;
结构SOCKADDR_IN clientaddr;
INT fdmax = 0;
INT newfd;
INT为nbytes;
INT的epfd = -1;
中期业绩= -1;
结构epoll_event EV;
INT I = 0;
INT索引= 0;
INT client_fd = -1; INT SnumOfConnection = 0; UDPPacket UDPPacket_obj;
结构SOCKADDR_IN client_sockaddr_in;
结构SOCKADDR_IN server_sockaddr_in; INT的sockfd [12] = {0};
INT宝姿[12] = {} 10011,10012,10013,10021,10022,10023,10031,10032,10033,10041,10042,10043; //测试只有12个端口
INT port_index = 0;
INT sockaddr_in_length = 0; 的printf(在主\\ n); / *与端口上面所列内容创建插座* /
为(port_index = 0; port_index&下; 12; port_index ++)
{
的sockfd [port_index] = create_sockets(宝姿[port_index]);
如果(的sockfd [port_index> fdmax)
fdmax =的sockfd [port_index]
}
的printf(SOC创建\\ n后); sockaddr_in_length = sizeof的(结构SOCKADDR_IN); 事件=释放calloc(MAX_CON,sizeof的(结构epoll_event));
如果((的epfd = epoll_create(MAX_CON))== -1)/ * * epoll_create /
{
PERROR(epoll_create);
出口(1);
}
ev.events = EPOLLIN;
ev.data.fd = fdmax; 为(port_index = 0; port_index&下; 12; port_index ++)
{
如果(epoll_ctl(epfd的,EPOLL_CTL_ADD,的sockfd [port_index],&放大器; EV)小于0)/ * epoll_ctl * /
{
PERROR(epoll_ctl);
出口(1);
}
} 而(1)
{
的printf(epoll_wait之前\\ n);
RES = epoll_wait(epfd的,事件,MAX_CON,-1); / * epoll_wait * /
的printf(epoll_wait \\ n后);
client_fd =事件[指数] .data.fd; 对于(指数= 0;指数 - LT; MAX_CON;指数++)
{
的printf(开始\\ n);
如果(事件[指数] .events&安培; EPOLLHUP)
{
如果(epoll_ctl(epfd的,EPOLL_CTL_DEL,client_fd,&放大器; EV)℃,){
PERROR(epoll_ctl);
}
关闭(client_fd);
打破;
}
的printf(EPOLLIN检查之前\\ n);
如果(事件[指数] .events&安培; EPOLLIN){
如果((为nbytes = recvfrom的(client_fd,&安培; UDPPacket_obj,sizeof的(UDPPacket),0,
(结构sockaddr *)及client_sockaddr_in,
&放大器; sockaddr_in_length))≤; = 0) {
如果(为nbytes == 0){
的printf(插座%d个挂了\\ n,client_fd);
}
其他{
输出(的recv()错误笑%d个!,client_fd);
PERROR();
} 如果(epoll_ctl(epfd的,EPOLL_CTL_DEL,client_fd,&放大器; EV)℃,){
PERROR(epoll_ctl);
}
//关闭(client_fd);
}
的printf(数据的recv =%s的\\ n,UDPPacket_obj.data);
}
}
} //而结束
返回0;
}
解决方案
您只等着在一个单一的套接字事件,一个在 fdmax
。
您需要添加的要轮询所有的插座。
Im trying to receive data from multiple UDP sockets using epoll. This is a test program it doesn't have exact number of sockets.( For testing purpose its set as 50.) The below program doesn't receive any data and it gets stuck at epoll_wait(), since i have given -1 it waits indefinetly till it gets data. But doesn't get any.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/epoll.h>
#include <fcntl.h>
#define MAX_CON (50)
typedef struct UDPMessage
{
unsigned short hdr;
unsigned short CC1;
unsigned short CC2;
unsigned char data[1472];
unsigned short CC3;
} UDPPacket;
static struct epoll_event *events;
int create_sockets(unsigned int port);
int create_sockets(unsigned int port)
{
int sock, flag = 1;
struct sockaddr_in sock_name;
/* Create a datagram socket*/
sock = socket(PF_INET, SOCK_DGRAM, 0);
/* Setting the socket to non blocking*/
fcntl(sock, F_SETFL, O_NONBLOCK);
if (sock < 0)
{
perror("socket");
exit(EXIT_FAILURE);
}
/* Set the reuse flag. */
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag)) < 0)
{
perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
exit(EXIT_FAILURE);
}
/* Give the socket a name. */
sock_name.sin_family = AF_INET;
sock_name.sin_port = htons(port);
sock_name.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(sock,(struct sockaddr *) &sock_name, sizeof(sock_name)) < 0)
{
perror("bind");
exit(EXIT_FAILURE);
}
return sock;
}
int main(int argc, char *argv[])
{
fd_set master;
fd_set read_fds;
struct sockaddr_in serveraddr;
struct sockaddr_in clientaddr;
int fdmax=0;
int newfd;
int nbytes;
int epfd = -1;
int res = -1;
struct epoll_event ev;
int i=0;
int index = 0;
int client_fd = -1;
int SnumOfConnection = 0;
UDPPacket UDPPacket_obj;
struct sockaddr_in client_sockaddr_in;
struct sockaddr_in server_sockaddr_in;
int sockfd[12]={0};
int PORTS[12] = { 10011,10012,10013,10021,10022,10023,10031,10032,10033,10041,10042,10043}; //TEST only 12 ports
int port_index=0;
int sockaddr_in_length=0;
printf("In main\n");
/* Create sockets with the above list of ports */
for( port_index=0;port_index<12;port_index++)
{
sockfd[port_index]=create_sockets(PORTS[port_index]);
if(sockfd[port_index] > fdmax)
fdmax = sockfd[port_index];
}
printf("after soc creation\n");
sockaddr_in_length = sizeof(struct sockaddr_in);
events = calloc(MAX_CON, sizeof(struct epoll_event));
if ((epfd = epoll_create(MAX_CON)) == -1) /* epoll_create */
{
perror("epoll_create");
exit(1);
}
ev.events = EPOLLIN;
ev.data.fd = fdmax;
for( port_index=0;port_index<12;port_index++)
{
if (epoll_ctl(epfd, EPOLL_CTL_ADD, sockfd[port_index], &ev) < 0) /* epoll_ctl */
{
perror("epoll_ctl");
exit(1);
}
}
while(1)
{
printf("Before epoll_wait\n");
res = epoll_wait(epfd, events, MAX_CON, -1); /* epoll_wait */
printf("After epoll_wait\n");
client_fd = events[index].data.fd;
for (index = 0; index < MAX_CON; index++)
{
printf("start\n");
if (events[index].events & EPOLLHUP)
{
if (epoll_ctl(epfd, EPOLL_CTL_DEL, client_fd, &ev) < 0) {
perror("epoll_ctl");
}
close(client_fd);
break;
}
printf("before EPOLLIN check\n");
if (events[index].events & EPOLLIN) {
if((nbytes = recvfrom(client_fd,&UDPPacket_obj,sizeof(UDPPacket),0,
(struct sockaddr *)&client_sockaddr_in,
&sockaddr_in_length)) <=0)
{
if(nbytes == 0) {
printf("socket %d hung up\n", client_fd);
}
else {
printf("recv() error lol! %d", client_fd);
perror("");
}
if (epoll_ctl(epfd, EPOLL_CTL_DEL, client_fd, &ev) < 0) {
perror("epoll_ctl");
}
//close(client_fd);
}
printf("Data recv=%s\n",UDPPacket_obj.data);
}
}
} //end of while
return 0;
}
解决方案
You are only waiting for events on one single socket, the one in fdmax
.
You need to add all sockets you want to poll.
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