I have a UDP Server that should sit and wait for a client to connect to it, and send it a string of a filename. Right now I just want it to echo back the filename to the client. Here is my code
Server
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#define MAXBUFLEN 1024
// Usage: ./server PORT
int main(int argc, char *argv[])
{
int sockfd;
struct sockaddr_in server;
size_t clientSize;
struct sockaddr_storage client;
char buf[MAXBUFLEN];
int portno = atoi(argv[1]);
int numbytes;
printf("Port: %d\n", portno);
// Create UDP Socket
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
perror("Can't create socket");
exit(-1);
}
// Configure socket
memset(&server, 0, sizeof server);
server.sin_family = AF_INET; // Use IPv4
server.sin_addr.s_addr = INADDR_ANY; // My IP
server.sin_port = htons(portno); // Server Port
// Bind socket
if ((bind(sockfd, (struct sockaddr *) &server, sizeof(server))) == -1) {
close(sockfd);
perror("Can't bind");
}
while (1) {
printf("Waiting for data...\n");
// Receive data from Client
clientSize = sizeof(client);
numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1,0,
(struct sockaddr *) &client, &clientSize);
buf[numbytes] = '\0';
printf("client sent: %s\n", buf);
// Rely to client
sendto(sockfd, buf, MAXBUFLEN-1, 0,
(struct sockaddr *) &client, &clientSize);
}
printf("Closing");
close(sockfd);
return 0;
}
Client
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#define MAXBUFLEN 1024
//Usage: ./client PORT IP FILE
int main(int argc, char *argv[]) {
int sockfd;
struct sockaddr_in server;
// struct sockaddr_storage client;
char buf[MAXBUFLEN];
int portno = atoi(argv[1]);
char *serverIP = argv[2];
char *filename = argv[3];
int numbytes;
printf("Port: %d, IP:%s, File:%s\n", portno, serverIP, filename);
// Create UDP Socket
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
perror("Can't create socket");
exit(-1);
}
// The server IP and Port
memset(&server, 0, sizeof server);
server.sin_family = AF_INET; // Use IPv4
server.sin_port = htons(portno); // Server Port
struct hostent *hp = gethostbyname(serverIP);
memcpy((char*)&server.sin_addr, (char*)hp->h_name, hp->h_length);
printf("Sent %s\n", filename);
// No need to bind, just send request for file
int serverSize = sizeof(server);
sendto(sockfd, argv[3], strlen(argv[3]), 0,
(struct sockaddr *) &server, serverSize);
printf("Waiting for reply\n");
recvfrom(sockfd, buf, MAXBUFLEN-1, 0,
(struct sockaddr *) &server, serverSize);
buf[numbytes] = '\0';
printf("server sent: %s\n", buf);
close(sockfd);
}
So far the Server just prints out
Waiting for data...
only once... so its never getting a request.
and the Client prints out:
./client 8083 127.0.0.1 hello
Port: 8083, IP:127.0.0.1, File:hello
Sent hello
Waiting for reply
server sent:
Please help, I'm new to the world of C and UDP Sockets.
Oh yeah, and I already read Beej's Guide... please don't just post that as an answer.