Lectures notes for 2010 - KTH

#include
#include
#include
#include
UDP listener example
#define bigBufferSize 8192
#define my_port 52000
#define destination_host "127.0.0.1"
main(argc, argv)
int argc;
char **argv;
{
int client_socket_fd; /* Socket to client, server */
struct sockaddr_in client_addr; /* client’s address */
struct sockaddr_in other_addr; /* other party’s address */
int other_addr_len;
char bigBuffer[bigBufferSize];
int sendto_flags=0;
/* create a UDP socket */
if ((client_socket_fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
perror("Unable to open socket"); exit(1); };
memset((char*)&client_addr, 0, sizeof(client_addr)); /* initialize address structure */
client_addr.sin_family=AF_INET;
client_addr.sin_port=htons(my_port);
client_addr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(client_socket_fd, (struct sockaddr*)&client_addr, sizeof(client_addr))==-1) {
close(client_socket_fd); exit(1); }
if ((recvfrom(client_socket_fd, bigBuffer, bigBufferSize,
sendto_flags, (struct sockaddr*)&other_addr, &other_addr_len)) == -1) {
perror("Unable to receive from socket"); close(client_socket_fd); exit(1); }
printf("Received packet from %s:%d\nData: %s\nString length=%d\n",
inet_ntoa(other_addr.sin_addr), ntohs(other_addr.sin_port), bigBuffer, strlen(bigBuffer));
close(client_socket_fd); exit(0);}
Maguire Simple UDP client 4: 22 of 74
maguire@kth.se 2010.03.21 Internetworking/Internetteknik