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Hello,
Please, I have a little problem, I hope you propose a solution. Thank you very much.
I developed a client task in C and a server task in C. The client needs the server IP address to connect to the server.
With Freepastry , I don't know in advance which machine will run the client and which machine will run the server so I can know the ip address of the server only at runtime
My question: how at run time the client will know the ip address of the server?
Thank you.
Cordially.
> The client needs the server IP address to connect to the server.
You mean like a web browser connecting to a web server
> My question: how at run time the client will know the ip address of the server?
Well for a browser, you type the address (of the server) into the address bar.
Hello,
Thank you very much for the help :
here is the client code:
here is the server code:Code:#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
/// CLIENT
int main(int argc, char *argv[])
{
printf("This is the client program\n");
int sockfd;
int len, rc ;
struct sockaddr_in address;
int result;
char ch = 'A';
//Create socket for client.
sockfd = socket(PF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
perror("Socket create failed.\n") ;
return -1 ;
}
//Name the socket as agreed with server.
address.sin_family = AF_INET;
address.sin_addr.s_addr = inet_addr("192.168.1.3");
address.sin_port = htons(1111);
len = sizeof(address);
result = connect(sockfd, (struct sockaddr *)&address, len);
if(result == -1)
{
perror("Error has occurred");
exit(-1);
}
char lettre;
while ( ch < 'Y') {
//Read and write via sockfd
// printf("donner lettre:");
// scanf("%c",&ch);
rc = write(sockfd, &ch, 1);
//printf("write rc = %d\n", rc ) ;
if (rc == -1) break ;
read(sockfd, &ch, 1);
printf("Char from server = %c\n", ch);
//if (ch == 'A') sleep(5) ; // pause 5 seconds
sleep(10);
ch++;
}
close(sockfd);
exit(0);
}
The client needs a server IP address (like 192.168.1.3) to connect to the server, the problem is that I do not know the ip address of the server before execution....Code:#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
/// SERVER
int main(int argc, char *argv[])
{
//Declaring process variables.
int server_sockfd, client_sockfd;
int server_len ;
int rc ;
unsigned client_len;
struct sockaddr_in server_address;
struct sockaddr_in client_address;
//Remove any old socket and create an unnamed socket for the server.
server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
server_address.sin_family = AF_INET;
server_address.sin_addr.s_addr = htons(INADDR_ANY);
server_address.sin_port = htons(1111) ;
server_len = sizeof(server_address);
rc = bind(server_sockfd, (struct sockaddr *) &server_address, server_len);
printf("RC from bind = %d\n", rc ) ;
//Create a connection queue and wait for clients
rc = listen(server_sockfd, 5);
printf("RC from listen = %d\n", rc ) ;
client_len = sizeof(client_address);
client_sockfd = accept(server_sockfd, (struct sockaddr *) &client_address, &client_len);
printf("after accept()... client_sockfd = %d\n", client_sockfd) ;
while(1)
{
char ch;
printf("server waiting\n");
//Accept a connection
//client_len = sizeof(client_address);
//client_sockfd = accept(server_sockfd, (struct sockaddr *) &client_address, &client_len);
//printf("after accept()... client_sockfd = %d\n", client_sockfd) ;
//Read write to client on client_sockfd
rc = read(client_sockfd, &ch, 1);
printf("Char from client = %c\n", ch);
//printf("RC from read = %d\n", rc ) ;
if (ch=='X') break ;
sleep(10);
ch++;
//printf("Donner une lettre (serveur):");
// scanf("%c",&ch);
write(client_sockfd, &ch, 1);
}
printf("server exiting\n");
//close(client_sockfd);
close(client_sockfd);
return 0;
}
Thank you so much
How big is the network you want to search?
Trying each one of 192.168.1.1 to 192.168.1.254 is easy enough to do.
I wonder if it is possible that the client sends a message broadcat "who is the server" to get the ip address of the server ?
Sure, you could do that as well.
Please can you guide me to modify my code to do this? Do you know a function that do this?
I searched on google, I have not found a tutorial explaining
Thank you so much for help
Really!?
Slightly Advanced Techniques
Then read the rest of the Beej tutorial, it has most of the stuff you're likely to need on a day to day basis.
Thank you so much for much for help :)
I have used the client code that makes the broadcacast:
But I do not know how I check the reception of this broadcast, do I need to do a client or a server that is listening on port 1111 ?Code://Socket Client
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#define BUFFER_TAILLE 10
int main (int argc, char *argv[]) {
/*******************************************/
char buffer[BUFFER_TAILLE]="ip address";
int sock;
int on = 1;
struct sockaddr_in sin;
if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket");
exit(1);
}
if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST,
&on, sizeof(on)) < 0) {
perror("setsockopt");
exit(1);
}
sin.sin_family = PF_INET;
sin.sin_addr.s_addr = INADDR_BROADCAST;
sin.sin_port = htons(1111);
if (bind(sock, (struct sockaddr *)&sin,
sizeof(sin)) < 0) {
perror("bind");
exit(1);
}
write(sock,buffer, 10);
close(sock);
/*************************************************************/
return 0;
}
Thank you so much for help
Best Regards.
Why not just use DNS?
Please can you explain more your idea?Quote:
Originally Posted by Elysia
Thanks a lot
Why does your post have better spelling, meaning and grammar than the title? First impressions are everything.
Run some software that reports the ip to a server on your server. Ther are free sevices for this.Quote:
Originally Posted by chercheur
Then, connect to that DNS.
Can you name one?Quote:
Originally Posted by Elysia
I thought that is for me to develop the code that makes the broadcast