test/select/test04_srv.c

   1 /*
   2  * Test name: test04_srv.c
   3  *
   4  * Objective: Test a simple UDP server
   5  *
   6  * Description: Implements a simple echo server using the UDP protocol. Instead
   7  * of blocking on read(), it performs a select call first blocking there
   8  * until there is data to be read
   9  */
  10
  11 #include <sys/types.h>
  12 #include <sys/ioctl.h>
  13 #include <sys/select.h>
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <stdlib.h>
  17 #include <stdarg.h>
  18 #include <fcntl.h>
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <net/netlib.h>
  22 #include <net/gen/netdb.h>
  23 #include <net/gen/in.h>
  24 #include <net/gen/udp.h>
  25 #include <net/gen/udp_hdr.h>
  26 #include <net/gen/udp_io.h>
  27 #include <net/hton.h>
  28
  29 #define PORT 6000L
  30
  31 /* type for received data */
  32 typedef struct
  33 {
  34   udp_io_hdr_t header;
  35   char data[1024];
  36 } udp_buffer_t;
  37
  38 int udp_conf(long port) {
  39
  40   char *udp_device;
  41   int netfd;
  42   nwio_udpopt_t udpopt;
  43
  44   /* Get default UDP device */
  45   if ((udp_device = getenv("UDP_DEVICE")) == NULL)
  46     udp_device = UDP_DEVICE;
  47
  48   /* Open UDP connection */
  49   if ((netfd = open(udp_device, O_RDWR)) < 0)
  50   {
  51     fprintf(stderr,"Error opening UDP connection\n");
  52     return -1;
  53   }
  54
  55   /* Configure UDP connection */
  56   udpopt.nwuo_flags = NWUO_COPY | NWUO_LP_SET | NWUO_EN_LOC | NWUO_DI_BROAD
  57                    | NWUO_RP_ANY | NWUO_RA_ANY | NWUO_RWDATALL | NWUO_DI_IPOPT;
  58
  59   udpopt.nwuo_locport = (udpport_t) htons(port);
  60
  61   if ((ioctl(netfd, NWIOSUDPOPT, &udpopt))<0)
  62   {
  63     fprintf(stderr,"Error configuring the connection\n");
  64     close(netfd);
  65     return -1;
  66   }
  67
  68   /* Get conf options */
  69   if ((ioctl(netfd, NWIOGUDPOPT, &udpopt))<0)
  70   {
  71     fprintf(stderr,"Error getting the conf\n");
  72     close(netfd);
  73     return -1;
  74   }
  75
  76   return netfd;
  77 }
  78
  79 int main(int argc,char *argv[]) {
  80   int fd;
  81   ssize_t data_read;
  82   udp_buffer_t buffer;
  83   ipaddr_t tmp_addr;
  84   udpport_t tmp_port;
  85   int ret;
  86   fd_set fds_read;
  87
  88   if ((fd = udp_conf(PORT)) < 0) {
  89         fprintf(stderr, "Error configuring UDP connection\n");
  90         exit(-1);
  91   }
  92   printf("Waiting for messages on port: %ld\n", PORT);
  93   fflush(stdout);
  94   /* Initialize fd_set */
  95   FD_ZERO(&fds_read);
  96   FD_SET(fd, &fds_read);
  97
  98   while (1)
  99   {
 100     /* Wait for data available to be read (no timeout) */
 101     ret = select(4, &fds_read, NULL, NULL, NULL);
 102     if (ret < 0) {
 103         fprintf(stderr, "Error on select: %d", errno);
 104         exit(-1);
 105     }
 106     if (!FD_ISSET(fd, &fds_read)) {
 107         printf("Error: network fd is not ready (?)\n");
 108         exit(-1);
 109     }
 110     printf("Ready to receive...\n");
 111     /* Read received data */
 112     data_read = read(fd, &buffer, sizeof(udp_buffer_t));
 113     printf("Received data: %s\n", buffer.data);
 114
 115     /* Can exit if the received string == exit */
 116     if (!strcmp(buffer.data,"exit"))
 117       break;
 118
 119     /* Send data back, swap addresses */
 120     tmp_addr = buffer.header.uih_src_addr;
 121     buffer.header.uih_src_addr = buffer.header.uih_dst_addr;
 122     buffer.header.uih_dst_addr = tmp_addr;
 123
 124     /* Swap ports */
 125     tmp_port = buffer.header.uih_src_port;
 126     buffer.header.uih_src_port = buffer.header.uih_dst_port;
 127     buffer.header.uih_dst_port = tmp_port;
 128
 129     /* Write the same back  */
 130     write(fd, &buffer, data_read);
 131   }
 132
 133   close(fd);
 134 }