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