minix/test/select/test04_srv.c

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/*
* Test name: test04_srv.c
*
* Objective: Test a simple UDP server
*
* Description: Implements a simple echo server using the UDP protocol. Instead
* of blocking on read(), it performs a select call first blocking there
* until there is data to be read
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <net/netlib.h>
#include <net/gen/netdb.h>
#include <net/gen/in.h>
#include <net/gen/udp.h>
#include <net/gen/udp_hdr.h>
#include <net/gen/udp_io.h>
#include <net/hton.h>
#define PORT 6000L
/* type for received data */
typedef struct
{
udp_io_hdr_t header;
char data[1024];
} udp_buffer_t;
int udp_conf(long port) {
char *udp_device;
int netfd;
nwio_udpopt_t udpopt;
/* Get default UDP device */
if ((udp_device = getenv("UDP_DEVICE")) == NULL)
udp_device = UDP_DEVICE;
/* Open UDP connection */
if ((netfd = open(udp_device, O_RDWR)) < 0)
{
fprintf(stderr,"Error opening UDP connection\n");
return -1;
}
/* Configure UDP connection */
udpopt.nwuo_flags = NWUO_COPY | NWUO_LP_SET | NWUO_EN_LOC | NWUO_DI_BROAD
| NWUO_RP_ANY | NWUO_RA_ANY | NWUO_RWDATALL | NWUO_DI_IPOPT;
udpopt.nwuo_locport = (udpport_t) htons(port);
if ((ioctl(netfd, NWIOSUDPOPT, &udpopt))<0)
{
fprintf(stderr,"Error configuring the connection\n");
close(netfd);
return -1;
}
/* Get conf options */
if ((ioctl(netfd, NWIOGUDPOPT, &udpopt))<0)
{
fprintf(stderr,"Error getting the conf\n");
close(netfd);
return -1;
}
return netfd;
}
int main(int argc,char *argv[]) {
int fd;
ssize_t data_read;
udp_buffer_t buffer;
ipaddr_t tmp_addr;
udpport_t tmp_port;
int ret;
fd_set fds_read;
if ((fd = udp_conf(PORT)) < 0) {
fprintf(stderr, "Error configuring UDP connection\n");
exit(-1);
}
printf("Waiting for messages on port: %ld\n", PORT);
fflush(stdout);
/* Initialize fd_set */
FD_ZERO(&fds_read);
FD_SET(fd, &fds_read);
while (1)
{
/* Wait for data available to be read (no timeout) */
ret = select(4, &fds_read, NULL, NULL, NULL);
if (ret < 0) {
fprintf(stderr, "Error on select: %d", errno);
exit(-1);
}
if (!FD_ISSET(fd, &fds_read)) {
printf("Error: network fd is not ready (?)\n");
exit(-1);
}
printf("Ready to receive...\n");
/* Read received data */
data_read = read(fd, &buffer, sizeof(udp_buffer_t));
printf("Received data: %s\n", buffer.data);
/* Can exit if the received string == exit */
if (!strcmp(buffer.data,"exit"))
break;
/* Send data back, swap addresses */
tmp_addr = buffer.header.uih_src_addr;
buffer.header.uih_src_addr = buffer.header.uih_dst_addr;
buffer.header.uih_dst_addr = tmp_addr;
/* Swap ports */
tmp_port = buffer.header.uih_src_port;
buffer.header.uih_src_port = buffer.header.uih_dst_port;
buffer.header.uih_dst_port = tmp_port;
/* Write the same back */
write(fd, &buffer, data_read);
}
close(fd);
}