linux epoll TCP UDP 实例

1)epoll 服务器端，TCP UDP都支持。

#include  <unistd.h>
#include  <sys/types.h>       /* basic system data types */
#include  <sys/socket.h>      /* basic socket definitions */
#include  <netinet/in.h>      /* sockaddr_in{} and other Internet defns */
#include  <arpa/inet.h>       /* inet(3) functions */
#include <sys/epoll.h> /* epoll function */
#include <fcntl.h>     /* nonblocking */
#include <sys/resource.h> /*setrlimit */

#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>

//#define UDP_CONNECT_WAY
//#define TCP_CONNECT_WAY

#define MAXEPOLLSIZE 10000
#define MAXLINE 10240
int handle(int connfd,struct sockaddr *clientaddr,socklen_t socklen);
int setnonblocking(int sockfd)
{
if (fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFD, 0)|O_NONBLOCK) == -1) {
return -1;
}
return 0;
}

int main(int argc, char **argv)
{
int  servPort = 6888;
int listenq = 1024;

int listenfd, connfd, kdpfd, nfds, n, nread, curfds,acceptCount = 0;
struct sockaddr_in servaddr, cliaddr;
socklen_t socklen = sizeof(struct sockaddr_in);
struct epoll_event ev;
struct epoll_event events[MAXEPOLLSIZE];
struct rlimit rt;
char buf[MAXLINE];

/* \u8bbe\u7f6e\u6bcf\u4e2a\u8fdb\u7a0b\u5141\u8bb8\u6253\u5f00\u7684\u6700\u5927\u6587\u4ef6\u6570 */
rt.rlim_max = rt.rlim_cur = MAXEPOLLSIZE;
if (setrlimit(RLIMIT_NOFILE, &rt) == -1)
{
perror("setrlimit error");
return -1;
}

bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl (INADDR_ANY);
servaddr.sin_port = htons (servPort);

#ifdef UDP_CONNECT_WAY
listenfd = socket(AF_INET, SOCK_DGRAM, 0);
#else
listenfd = socket(AF_INET, SOCK_STREAM, 0);
#endif

if (listenfd == -1) {
perror("can't create socket file");
return -1;
}

int opt = 1;
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

if (setnonblocking(listenfd) < 0) {
perror("setnonblock error");
}

//get buffer

int rev_buff_size = 0;
int send_buff_size = 0;
socklen_t optlen;
optlen = sizeof(rev_buff_size);
if(0 == getsockopt(listenfd, SOL_SOCKET, SO_RCVBUF, &rev_buff_size, &optlen))
{
printf("default socket receive buff size  %d bytes = %d KB  \n",rev_buff_size,rev_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

optlen = sizeof(send_buff_size);
if(0 == getsockopt(listenfd, SOL_SOCKET, SO_SNDBUF, &send_buff_size, &optlen))
{
printf("default socket send buff size  %d bytes = %d KB  \n",send_buff_size,send_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

if (bind(listenfd, (struct sockaddr *) &servaddr, sizeof(struct sockaddr)) == -1)
{
perror("bind error");
return -1;
}

#ifdef UDP_CONNECT_WAY

#else
if (listen(listenfd, listenq) == -1)
{
perror("listen error");
return -1;
}
#endif

if(0 == getsockopt(listenfd, SOL_SOCKET, SO_RCVBUF, &rev_buff_size, &optlen))
{
printf("1default socket receive buff size  %d bytes = %d KB  \n",rev_buff_size,rev_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

optlen = sizeof(send_buff_size);
if(0 == getsockopt(listenfd, SOL_SOCKET, SO_SNDBUF, &send_buff_size, &optlen))
{
printf("1default socket send buff size  %d bytes = %d KB  \n",send_buff_size,send_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

/* \u521b\u5efa epoll \u53e5\u67c4\uff0c\u628a\u76d1\u542c socket \u52a0\u5165\u5230 epoll \u96c6\u5408\u91cc */
kdpfd = epoll_create(MAXEPOLLSIZE);
ev.events = EPOLLIN | EPOLLET;
ev.data.fd = listenfd;
if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, listenfd, &ev) < 0)
{
fprintf(stderr, "epoll set insertion error: fd=%d\n", listenfd);
return -1;
}
curfds = 1;

printf("epollserver startup,port %d, max connection is %d, backlog is %d\n", servPort, MAXEPOLLSIZE, listenq);

for (;;) {
/* \u7b49\u5f85\u6709\u4e8b\u4ef6\u53d1\u751f */
nfds = epoll_wait(kdpfd, events, curfds, -1);
if (nfds == -1)
{
perror("epoll_wait");
continue;
}
/* \u5904\u7406\u6240\u6709\u4e8b\u4ef6 */
for (n = 0; n < nfds; ++n)
{
if (events
.data.fd == listenfd)
{
#ifdef UDP_CONNECT_WAY

#else
connfd = accept(listenfd, (struct sockaddr *)&cliaddr,&socklen);
if (connfd < 0)
{
perror("accept error");
continue;
}

sprintf(buf, "accept form %s:%d\n", inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port);
printf("%d:%s", ++acceptCount, buf);

if (curfds >= MAXEPOLLSIZE) {
fprintf(stderr, "too many connection, more than %d\n", MAXEPOLLSIZE);
close(connfd);
continue;
}
if (setnonblocking(connfd) < 0) {
perror("setnonblocking error");
}
ev.events = EPOLLIN | EPOLLET;
ev.data.fd = connfd;
if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, connfd, &ev) < 0)
{
fprintf(stderr, "add socket '%d' to epoll failed: %s\n", connfd, strerror(errno));
return -1;
}
curfds++;
continue;
#endif
}
// \u5904\u7406\u5ba2\u6237\u7aef\u8bf7\u6c42
if (handle(events
.data.fd,(struct sockaddr *)&cliaddr,socklen) < 0) {
epoll_ctl(kdpfd, EPOLL_CTL_DEL, events
.data.fd,&ev);
curfds--;

}
}
}
close(listenfd);
return 0;
}
int handle(int connfd,struct sockaddr *clientaddr,socklen_t socklen) {
int nread;
char buf[MAXLINE];

//  socklen_t socklen = 0;
//  struct sockaddr_in clientaddr;
//   socklen = sizeof(struct sockaddr);

memset(buf,0,sizeof(buf));
#ifdef UDP_CONNECT_WAY
nread = recvfrom(connfd,buf,sizeof(buf),0,(struct sockaddr*)clientaddr,&socklen);
#else
//nread = read(connfd, buf, MAXLINE);//\u8bfb\u53d6\u5ba2\u6237\u7aefsocket\u6d41
nread = recvfrom(connfd,buf,sizeof(buf),0,(struct sockaddr*)clientaddr,&socklen);
#endif

if (nread == 0)
{
printf("client close the connection\n");
close(connfd);
return -1;
}
else  if (nread < 0) {
perror("read error");
close(connfd);
return -1;
}
else
{
printf("Receive client %s:%d on  socket :%d  :%s\n", inet_ntoa(((struct sockaddr_in*)clientaddr)->sin_addr),((struct sockaddr_in*)clientaddr)->sin_port,connfd,buf);

#ifdef UDP_CONNECT_WAY
sendto(connfd,buf,nread,0,(struct sockaddr*)clientaddr,socklen);
#else
//write(connfd, buf, nread);//\u54cd\u5e94\u5ba2\u6237\u7aef
sendto(connfd,buf,nread,0,(struct sockaddr*)clientaddr,socklen);
#endif

}
return 0;
}

2）客服端

#include  <unistd.h>
#include  <sys/types.h>       /* basic system data types */
#include  <sys/socket.h>      /* basic socket definitions */
#include  <netinet/in.h>      /* sockaddr_in{} and other Internet defns */
#include  <arpa/inet.h>       /* inet(3) functions */
#include <netdb.h> /*gethostbyname function */

#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>

//#define UDP_CONNECT_WAY

#define MAXLINE 1024

void handle(int sockfd,struct sockaddr *servaddr,socklen_t addrlen);

int main(int argc, char **argv)
{
char * servInetAddr = "127.0.0.1";
int servPort = 6888;
char buf[MAXLINE];
int connfd;
struct sockaddr_in servaddr;
struct sockaddr_in clientaddr;
socklen_t length = 0;

if (argc == 2) {
servInetAddr = argv[1];
}
if (argc == 3) {
servInetAddr = argv[1];
servPort = atoi(argv[2]);
}
if (argc > 3) {
printf("usage: echoclient <IPaddress> <Port>\n");
return -1;
}

#ifdef UDP_CONNECT_WAY
connfd = socket(AF_INET, SOCK_DGRAM, 0);
#else
connfd = socket(AF_INET, SOCK_STREAM, 0);
#endif

//get buffer

int rev_buff_size = 0;
int send_buff_size = 0;
socklen_t optlen;
optlen = sizeof(rev_buff_size);
if(0 == getsockopt(connfd, SOL_SOCKET, SO_RCVBUF, &rev_buff_size, &optlen))
{
printf("default socket receive buff size  %d bytes = %d KB  \n",rev_buff_size,rev_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

optlen = sizeof(send_buff_size);
if(0 == getsockopt(connfd, SOL_SOCKET, SO_SNDBUF, &send_buff_size, &optlen))
{
printf("default socket send buff size  %d bytes = %d KB  \n",send_buff_size,send_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(servPort);
inet_pton(AF_INET, servInetAddr, &servaddr.sin_addr);

//set buffer
/*
rev_buff_size = 130;
if(setsockopt(connfd, SOL_SOCKET, SO_RCVBUF, (const char*)&rev_buff_size, sizeof(int)))
{
printf("Error: Set socket receive buffer failed.\n");
return -1;
}
send_buff_size = 512;
if(setsockopt(connfd, SOL_SOCKET, SO_SNDBUF, (const char*)&send_buff_size, sizeof(int)))
{
printf("Error: Set socket send buffer failed.\n");
return -1;
}

//get
optlen = sizeof(rev_buff_size);
if(0 == getsockopt(connfd, SOL_SOCKET, SO_RCVBUF, &rev_buff_size, &optlen))
{
printf("1default socket receive buff size  %d bytes = %d KB  \n",rev_buff_size,rev_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}

optlen = sizeof(send_buff_size);
if(0 == getsockopt(connfd, SOL_SOCKET, SO_SNDBUF, &send_buff_size, &optlen))
{
printf("1default socket send buff size  %d bytes = %d KB  \n",send_buff_size,send_buff_size/1024);
}
else
{
printf("errorNo. %d \n",errno);
}
*/

#if 0

int opt = 1;
setsockopt(connfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

bzero(&clientaddr, sizeof(clientaddr));
clientaddr.sin_family = AF_INET;
clientaddr.sin_addr.s_addr = htonl (INADDR_ANY);
clientaddr.sin_port = htons (9000);

if (bind(connfd, (struct sockaddr *) &clientaddr, sizeof(struct sockaddr)) == -1)
{
perror("bind error");
return -1;
}
#endif

#ifdef UDP_CONNECT
if (connect(connfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
perror("connect error");
return -1;
}
#endif

printf("welcome to echoclient\n");
length = sizeof(servaddr);
handle(connfd,(struct sockaddr*)&servaddr,length);  /* do it all */
close(connfd);
printf("exit\n");
exit(0);
}

void handle(int sockfd,struct sockaddr *servaddr,socklen_t addrlen)
{
char sendline[MAXLINE], recvline[MAXLINE];
int n;
for (;;) {
if (fgets(sendline, MAXLINE, stdin) == NULL) {
break;//read eof
}
/*
//\u4e5f\u53ef\u4ee5\u4e0d\u7528\u6807\u51c6\u5e93\u7684\u7f13\u51b2\u6d41,\u76f4\u63a5\u4f7f\u7528\u7cfb\u7edf\u51fd\u6570\u65e0\u7f13\u5b58\u64cd\u4f5c
if (read(STDIN_FILENO, sendline, MAXLINE) == 0) {
break;//read eof
}
*/

#ifdef UDP_CONNECT
n = write(sockfd, sendline, strlen(sendline));
#else
n = sendto(sockfd,sendline,strlen(sendline),0,(struct sockaddr*)servaddr,addrlen);
#endif
if(n>0)
{
printf("send size :%d \n",n);
#ifdef UDP_CONNECT
n = read(sockfd, recvline, MAXLINE);
#else
n = recvfrom(sockfd,recvline,sizeof(recvline),0,NULL,NULL);
#endif
if (n == 0) {
printf("echoclient: server terminated prematurely\n");
break;
}
else if (-1 == n)
{
perror("read error!");
}
else
{
write(STDOUT_FILENO, recvline, n);
}
}
else
{
printf("send size :%d \n",n);
perror("send fail!");
}
//\u5982\u679c\u7528\u6807\u51c6\u5e93\u7684\u7f13\u5b58\u6d41\u8f93\u51fa\u6709\u65f6\u4f1a\u51fa\u73b0\u95ee\u9898
//fputs(recvline, stdout);
}
}

3）编译

//UDP server

g++ -DUDP_CONNECT_WAY -g echoserver.cpp -oechoserver

// client

g++ -DUDP_CONNECT_WAY -DUDP_CONNECT -gechoclient.cpp -o echoclien

or

g++ -DUDP_CONNECT_WAY -g echoclient.cpp -oechoclien

//////////TCP/////////////

//server

g++ -g echoserver.cpp -o echoserver

//client

g++ -DUDP_CONNECT -g echoclient.cpp -oechoclien

4）参考
http://www.cnblogs.com/ggjucheng/archive/2012/01/17/2324974.html