select
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <errno.h>
#define SERVER_PORT 12345
#define TRUE 1
#define FALSE 0
main (int argc, char *argv[])
{
int i, len, rc, on = 1;
int listen_sd, max_sd, new_sd;
int desc_ready, end_server = FALSE;
int close_conn;
char buffer[80];
struct sockaddr_in6 addr;
struct timeval timeout;
fd_set master_set, working_set;
/*************************************************************/
/* Create an AF_INET6 stream socket to receive incoming */
/* connections on */
/*************************************************************/
listen_sd = socket(AF_INET6, SOCK_STREAM, 0);
if (listen_sd < 0)
{
perror("socket() failed");
exit(-1);
}
/*************************************************************/
/* Allow socket descriptor to be reuseable */
/*************************************************************/
rc = setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR,
(char *)&on, sizeof(on));
if (rc < 0)
{
perror("setsockopt() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Set socket to be nonblocking. All of the sockets for */
/* the incoming connections will also be nonblocking since */
/* they will inherit that state from the listening socket. */
/*************************************************************/
rc = ioctl(listen_sd, FIONBIO, (char *)&on);
if (rc < 0)
{
perror("ioctl() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Bind the socket */
/*************************************************************/
memset(&addr, 0, sizeof(addr));
addr.sin6_family = AF_INET6;
memcpy(&addr.sin6_addr, &in6addr_any, sizeof(in6addr_any));
addr.sin6_port = htons(SERVER_PORT);
rc = bind(listen_sd,
(struct sockaddr *)&addr, sizeof(addr));
if (rc < 0)
{
perror("bind() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Set the listen back log */
/*************************************************************/
rc = listen(listen_sd, 32);
if (rc < 0)
{
perror("listen() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Initialize the master fd_set */
/*************************************************************/
FD_ZERO(&master_set);
max_sd = listen_sd;
FD_SET(listen_sd, &master_set);
/*************************************************************/
/* Initialize the timeval struct to 3 minutes. If no */
/* activity after 3 minutes this program will end. */
/*************************************************************/
timeout.tv_sec = 3 * 60;
timeout.tv_usec = 0;
/*************************************************************/
/* Loop waiting for incoming connects or for incoming data */
/* on any of the connected sockets. */
/*************************************************************/
do
{
/**********************************************************/
/* Copy the master fd_set over to the working fd_set. */
/**********************************************************/
memcpy(&working_set, &master_set, sizeof(master_set));
/**********************************************************/
/* Call select() and wait 3 minutes for it to complete. */
/**********************************************************/
printf("Waiting on select()...\n");
rc = select(max_sd + 1, &working_set, NULL, NULL, &timeout);
/**********************************************************/
/* Check to see if the select call failed. */
/**********************************************************/
if (rc < 0)
{
perror(" select() failed");
break;
}
/**********************************************************/
/* Check to see if the 3 minute time out expired. */
/**********************************************************/
if (rc == 0)
{
printf(" select() timed out. End program.\n");
break;
}
/**********************************************************/
/* One or more descriptors are readable. Need to */
/* determine which ones they are. */
/**********************************************************/
desc_ready = rc;
for (i=0; i <= max_sd && desc_ready > 0; ++i)
{
/*******************************************************/
/* Check to see if this descriptor is ready */
/*******************************************************/
if (FD_ISSET(i, &working_set))
{
/****************************************************/
/* A descriptor was found that was readable - one */
/* less has to be looked for. This is being done */
/* so that we can stop looking at the working set */
/* once we have found all of the descriptors that */
/* were ready. */
/****************************************************/
desc_ready -= 1;
/****************************************************/
/* Check to see if this is the listening socket */
/****************************************************/
if (i == listen_sd)
{
printf(" Listening socket is readable\n");
/*************************************************/
/* Accept all incoming connections that are */
/* queued up on the listening socket before we */
/* loop back and call select again. */
/*************************************************/
do
{
/**********************************************/
/* Accept each incoming connection. If */
/* accept fails with EWOULDBLOCK, then we */
/* have accepted all of them. Any other */
/* failure on accept will cause us to end the */
/* server. */
/**********************************************/
new_sd = accept(listen_sd, NULL, NULL);
if (new_sd < 0)
{
if (errno != EWOULDBLOCK)
{
perror(" accept() failed");
end_server = TRUE;
}
break;
}
/**********************************************/
/* Add the new incoming connection to the */
/* master read set */
/**********************************************/
printf(" New incoming connection - %d\n", new_sd);
FD_SET(new_sd, &master_set);
if (new_sd > max_sd)
max_sd = new_sd;
/**********************************************/
/* Loop back up and accept another incoming */
/* connection */
/**********************************************/
} while (new_sd != -1);
}
/****************************************************/
/* This is not the listening socket, therefore an */
/* existing connection must be readable */
/****************************************************/
else
{
printf(" Descriptor %d is readable\n", i);
close_conn = FALSE;
/*************************************************/
/* Receive all incoming data on this socket */
/* before we loop back and call select again. */
/*************************************************/
do
{
/**********************************************/
/* Receive data on this connection until the */
/* recv fails with EWOULDBLOCK. If any other */
/* failure occurs, we will close the */
/* connection. */
/**********************************************/
rc = recv(i, buffer, sizeof(buffer), 0);
if (rc < 0)
{
if (errno != EWOULDBLOCK)
{
perror(" recv() failed");
close_conn = TRUE;
}
break;
}
/**********************************************/
/* Check to see if the connection has been */
/* closed by the client */
/**********************************************/
if (rc == 0)
{
printf(" Connection closed\n");
close_conn = TRUE;
break;
}
/**********************************************/
/* Data was received */
/**********************************************/
len = rc;
printf(" %d bytes received\n", len);
/**********************************************/
/* Echo the data back to the client */
/**********************************************/
rc = send(i, buffer, len, 0);
if (rc < 0)
{
perror(" send() failed");
close_conn = TRUE;
break;
}
} while (TRUE);
/*************************************************/
/* If the close_conn flag was turned on, we need */
/* to clean up this active connection. This */
/* clean up process includes removing the */
/* descriptor from the master set and */
/* determining the new maximum descriptor value */
/* based on the bits that are still turned on in */
/* the master set. */
/*************************************************/
if (close_conn)
{
close(i);
FD_CLR(i, &master_set);
if (i == max_sd)
{
while (FD_ISSET(max_sd, &master_set) == FALSE)
max_sd -= 1;
}
}
} /* End of existing connection is readable */
} /* End of if (FD_ISSET(i, &working_set)) */
} /* End of loop through selectable descriptors */
} while (end_server == FALSE);
/*************************************************************/
/* Clean up all of the sockets that are open */
/*************************************************************/
for (i=0; i <= max_sd; ++i)
{
if (FD_ISSET(i, &master_set))
close(i);
}
}
poll
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <errno.h>
#define SERVER_PORT 12345
#define TRUE 1
#define FALSE 0
main (int argc, char *argv[])
{
int len, rc, on = 1;
int listen_sd = -1, new_sd = -1;
int desc_ready, end_server = FALSE, compress_array = FALSE;
int close_conn;
char buffer[80];
struct sockaddr_in6 addr;
int timeout;
struct pollfd fds[200];
int nfds = 1, current_size = 0, i, j;
/*************************************************************/
/* Create an AF_INET6 stream socket to receive incoming */
/* connections on */
/*************************************************************/
listen_sd = socket(AF_INET6, SOCK_STREAM, 0);
if (listen_sd < 0)
{
perror("socket() failed");
exit(-1);
}
/*************************************************************/
/* Allow socket descriptor to be reuseable */
/*************************************************************/
rc = setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR,
(char *)&on, sizeof(on));
if (rc < 0)
{
perror("setsockopt() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Set socket to be nonblocking. All of the sockets for */
/* the incoming connections will also be nonblocking since */
/* they will inherit that state from the listening socket. */
/*************************************************************/
rc = ioctl(listen_sd, FIONBIO, (char *)&on);
if (rc < 0)
{
perror("ioctl() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Bind the socket */
/*************************************************************/
memset(&addr, 0, sizeof(addr));
addr.sin6_family = AF_INET6;
memcpy(&addr.sin6_addr, &in6addr_any, sizeof(in6addr_any));
addr.sin6_port = htons(SERVER_PORT);
rc = bind(listen_sd,
(struct sockaddr *)&addr, sizeof(addr));
if (rc < 0)
{
perror("bind() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Set the listen back log */
/*************************************************************/
rc = listen(listen_sd, 32);
if (rc < 0)
{
perror("listen() failed");
close(listen_sd);
exit(-1);
}
/*************************************************************/
/* Initialize the pollfd structure */
/*************************************************************/
memset(fds, 0 , sizeof(fds));
/*************************************************************/
/* Set up the initial listening socket */
/*************************************************************/
fds[0].fd = listen_sd;
fds[0].events = POLLIN;
/*************************************************************/
/* Initialize the timeout to 3 minutes. If no */
/* activity after 3 minutes this program will end. */
/* timeout value is based on milliseconds. */
/*************************************************************/
timeout = (3 * 60 * 1000);
/*************************************************************/
/* Loop waiting for incoming connects or for incoming data */
/* on any of the connected sockets. */
/*************************************************************/
do
{
/***********************************************************/
/* Call poll() and wait 3 minutes for it to complete. */
/***********************************************************/
printf("Waiting on poll()...\n");
rc = poll(fds, nfds, timeout);
/***********************************************************/
/* Check to see if the poll call failed. */
/***********************************************************/
if (rc < 0)
{
perror(" poll() failed");
break;
}
/***********************************************************/
/* Check to see if the 3 minute time out expired. */
/***********************************************************/
if (rc == 0)
{
printf(" poll() timed out. End program.\n");
break;
}
/***********************************************************/
/* One or more descriptors are readable. Need to */
/* determine which ones they are. */
/***********************************************************/
current_size = nfds;
for (i = 0; i < current_size; i++)
{
/*********************************************************/
/* Loop through to find the descriptors that returned */
/* POLLIN and determine whether it's the listening */
/* or the active connection. */
/*********************************************************/
if(fds[i].revents == 0)
continue;
/*********************************************************/
/* If revents is not POLLIN, it's an unexpected result, */
/* log and end the server. */
/*********************************************************/
if(fds[i].revents != POLLIN)
{
printf(" Error! revents = %d\n", fds[i].revents);
end_server = TRUE;
break;
}
if (fds[i].fd == listen_sd)
{
/*******************************************************/
/* Listening descriptor is readable. */
/*******************************************************/
printf(" Listening socket is readable\n");
/*******************************************************/
/* Accept all incoming connections that are */
/* queued up on the listening socket before we */
/* loop back and call poll again. */
/*******************************************************/
do
{
/*****************************************************/
/* Accept each incoming connection. If */
/* accept fails with EWOULDBLOCK, then we */
/* have accepted all of them. Any other */
/* failure on accept will cause us to end the */
/* server. */
/*****************************************************/
new_sd = accept(listen_sd, NULL, NULL);
if (new_sd < 0)
{
if (errno != EWOULDBLOCK)
{
perror(" accept() failed");
end_server = TRUE;
}
break;
}
/*****************************************************/
/* Add the new incoming connection to the */
/* pollfd structure */
/*****************************************************/
printf(" New incoming connection - %d\n", new_sd);
fds[nfds].fd = new_sd;
fds[nfds].events = POLLIN;
nfds++;
/*****************************************************/
/* Loop back up and accept another incoming */
/* connection */
/*****************************************************/
} while (new_sd != -1);
}
/*********************************************************/
/* This is not the listening socket, therefore an */
/* existing connection must be readable */
/*********************************************************/
else
{
printf(" Descriptor %d is readable\n", fds[i].fd);
close_conn = FALSE;
/*******************************************************/
/* Receive all incoming data on this socket */
/* before we loop back and call poll again. */
/*******************************************************/
do
{
/*****************************************************/
/* Receive data on this connection until the */
/* recv fails with EWOULDBLOCK. If any other */
/* failure occurs, we will close the */
/* connection. */
/*****************************************************/
rc = recv(fds[i].fd, buffer, sizeof(buffer), 0);
if (rc < 0)
{
if (errno != EWOULDBLOCK)
{
perror(" recv() failed");
close_conn = TRUE;
}
break;
}
/*****************************************************/
/* Check to see if the connection has been */
/* closed by the client */
/*****************************************************/
if (rc == 0)
{
printf(" Connection closed\n");
close_conn = TRUE;
break;
}
/*****************************************************/
/* Data was received */
/*****************************************************/
len = rc;
printf(" %d bytes received\n", len);
/*****************************************************/
/* Echo the data back to the client */
/*****************************************************/
rc = send(fds[i].fd, buffer, len, 0);
if (rc < 0)
{
perror(" send() failed");
close_conn = TRUE;
break;
}
} while(TRUE);
/*******************************************************/
/* If the close_conn flag was turned on, we need */
/* to clean up this active connection. This */
/* clean up process includes removing the */
/* descriptor. */
/*******************************************************/
if (close_conn)
{
close(fds[i].fd);
fds[i].fd = -1;
compress_array = TRUE;
}
} /* End of existing connection is readable */
} /* End of loop through pollable descriptors */
/***********************************************************/
/* If the compress_array flag was turned on, we need */
/* to squeeze together the array and decrement the number */
/* of file descriptors. We do not need to move back the */
/* events and revents fields because the events will always*/
/* be POLLIN in this case, and revents is output. */
/***********************************************************/
if (compress_array)
{
compress_array = FALSE;
for (i = 0; i < nfds; i++)
{
if (fds[i].fd == -1)
{
for(j = i; j < nfds-1; j++)
{
fds[j].fd = fds[j+1].fd;
}
i--;
nfds--;
}
}
}
} while (end_server == FALSE); /* End of serving running. */
/*************************************************************/
/* Clean up all of the sockets that are open */
/*************************************************************/
for (i = 0; i < nfds; i++)
{
if(fds[i].fd >= 0)
close(fds[i].fd);
}
}
epoll
/*
* Attention:
* To keep things simple, do not handle socket/bind/listen/.../epoll_create/epoll_wait API error
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_PORT 8080
#define MAX_CONN 16
#define MAX_EVENTS 32
#define BUF_SIZE 16
#define MAX_LINE 256
void server_run();
void client_run();
int main(int argc, char *argv[])
{
int opt;
char role = 's';
while ((opt = getopt(argc, argv, "cs")) != -1) {
switch (opt) {
case 'c':
role = 'c';
break;
case 's':
break;
default:
printf("usage: %s [-cs]\n", argv[0]);
exit(1);
}
}
if (role == 's') {
server_run();
} else {
client_run();
}
return 0;
}
/*
* register events of fd to epfd
*/
static void epoll_ctl_add(int epfd, int fd, uint32_t events)
{
struct epoll_event ev;
ev.events = events;
ev.data.fd = fd;
if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev) == -1) {
perror("epoll_ctl()\n");
exit(1);
}
}
static void set_sockaddr(struct sockaddr_in *addr)
{
bzero((char *)addr, sizeof(struct sockaddr_in));
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = INADDR_ANY;
addr->sin_port = htons(DEFAULT_PORT);
}
static int setnonblocking(int sockfd)
{
if (fcntl(sockfd, F_SETFD, fcntl(sockfd, F_GETFD, 0) | O_NONBLOCK) ==
-1) {
return -1;
}
return 0;
}
/*
* epoll echo server
*/
void server_run()
{
int i;
int n;
int epfd;
int nfds;
int listen_sock;
int conn_sock;
int socklen;
char buf[BUF_SIZE];
struct sockaddr_in srv_addr;
struct sockaddr_in cli_addr;
struct epoll_event events[MAX_EVENTS];
listen_sock = socket(AF_INET, SOCK_STREAM, 0);
set_sockaddr(&srv_addr);
bind(listen_sock, (struct sockaddr *)&srv_addr, sizeof(srv_addr));
setnonblocking(listen_sock);
listen(listen_sock, MAX_CONN);
epfd = epoll_create(1);
epoll_ctl_add(epfd, listen_sock, EPOLLIN | EPOLLOUT | EPOLLET);
socklen = sizeof(cli_addr);
for (;;) {
nfds = epoll_wait(epfd, events, MAX_EVENTS, -1);
for (i = 0; i < nfds; i++) {
if (events[i].data.fd == listen_sock) {
/* handle new connection */
conn_sock =
accept(listen_sock,
(struct sockaddr *)&cli_addr,
&socklen);
inet_ntop(AF_INET, (char *)&(cli_addr.sin_addr),
buf, sizeof(cli_addr));
printf("[+] connected with %s:%d\n", buf,
ntohs(cli_addr.sin_port));
setnonblocking(conn_sock);
epoll_ctl_add(epfd, conn_sock,
EPOLLIN | EPOLLET | EPOLLRDHUP |
EPOLLHUP);
} else if (events[i].events & EPOLLIN) {
/* handle EPOLLIN event */
for (;;) {
bzero(buf, sizeof(buf));
n = read(events[i].data.fd, buf,
sizeof(buf));
if (n <= 0 /* || errno == EAGAIN */ ) {
break;
} else {
printf("[+] data: %s\n", buf);
write(events[i].data.fd, buf,
strlen(buf));
}
}
} else {
printf("[+] unexpected\n");
}
/* check if the connection is closing */
if (events[i].events & (EPOLLRDHUP | EPOLLHUP)) {
printf("[+] connection closed\n");
epoll_ctl(epfd, EPOLL_CTL_DEL,
events[i].data.fd, NULL);
close(events[i].data.fd);
continue;
}
}
}
}
/*
* test clinet
*/
void client_run()
{
int n;
int c;
int sockfd;
char buf[MAX_LINE];
struct sockaddr_in srv_addr;
sockfd = socket(AF_INET, SOCK_STREAM, 0);
set_sockaddr(&srv_addr);
if (connect(sockfd, (struct sockaddr *)&srv_addr, sizeof(srv_addr)) < 0) {
perror("connect()");
exit(1);
}
for (;;) {
printf("input: ");
fgets(buf, sizeof(buf), stdin);
c = strlen(buf) - 1;
buf[c] = '\0';
write(sockfd, buf, c + 1);
bzero(buf, sizeof(buf));
while (errno != EAGAIN
&& (n = read(sockfd, buf, sizeof(buf))) > 0) {
printf("echo: %s\n", buf);
bzero(buf, sizeof(buf));
c -= n;
if (c <= 0) {
break;
}
}
}
close(sockfd);
}
