client - server

I have decided to write client-server aplications on my own.

so far I manage to do this:

client.c

Code:

---


#include <stdio.h>
#include <string.h>
#include <winsock2.h>
#define version 0x002
#define MYPORT 3490
int main()
{
        WSADATA wsaData;
        SOCKET socketfd;
        struct sockaddr_in server_addr;
        char message[]="Hello FANTA!";
        if(WSAStartup(MAKEWORD(version,2),&wsaData))
        {
                fprintf(stderr,"\nError intializing winsock library!");
                return 1;
        }
        server_addr.sin_family=AF_INET;
        server_addr.sin_port=htons(MYPORT);
        server_addr.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
        memset(&(server_addr.sin_zero),'\0',8);
       
        socketfd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(socketfd==INVALID_SOCKET)
        {
                fprintf(stderr,"\nError creating socket!");
                return 1;
        }

        if(connect(socketfd,(const struct sockaddr*)&server_addr,sizeof(struct sockaddr)))
        {
                fprintf(stdout,"Could not be connected!");
                return 1;
        }
        if(send(socketfd,message,lstrlen(message),0)==SOCKET_ERROR)
        {
                fprintf(stderr,"Data could not be send!");
                return 1;
        }

}

---

server.c

Code:

---


#include <stdio.h>
#include <string.h>
#include <winsock2.h>
#define version 0x002
#define MYPORT 3490
#define bufsize 128
int main()
{
        WSADATA wsaData;
        SOCKET socketfd,new_fd;
        struct sockaddr_in my_addr,client_sockaddr;
        char message[bufsize];
        int size;
        if(WSAStartup(MAKEWORD(version,2),&wsaData))
        {
                fprintf(stderr,"\nError intializing winsock library!");
                return 1;
        }
        my_addr.sin_family=AF_INET;
        my_addr.sin_port=htons(MYPORT);
        my_addr.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
        memset(&(my_addr.sin_zero),'\0',8);
       
        socketfd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(socketfd==INVALID_SOCKET)
        {
                fprintf(stderr,"\nError creating socket!");
                return 1;
        }

        if(bind(socketfd,(const struct sockaddr*)&my_addr,sizeof(struct sockaddr))==SOCKET_ERROR)
        {
                fprintf(stderr,"Error binding");
                return 1;
        }

        if(listen(socketfd,1)==SOCKET_ERROR)
        {
                fprintf(stderr,"Error listening!");
                return 1;
        }
        size=sizeof(struct sockaddr);
        new_fd=accept(socketfd,(struct sockaddr*)&client_sockaddr,&size);
        if(new_fd==INVALID_SOCKET)
        {
                fprintf(stderr,"\nError accepting connection!");
                return 1;
        }
        while(1)
        {
                int get;
               
                get=recv(new_fd,message,bufsize-1,0);

                if(get==0)
                        break;
                else
                        if(get==SOCKET_ERROR)
                        {
                                fprintf(stderr,"\nError receiving data!");
                                return 1;
                        }
                        else
                        {
                                message[get]=0;
                                fprintf(stdout,"%s ",message);
                        }

        }
        closesocket(new_fd);
        closesocket(socketfd);
        WSACleanup();
}

---

As you might guess it's not working.

I start server.exe and and after that client.exe, but nothing is happening I see no message on server window.
I feel I'm very near.

I'm total beginer in this stuff so any help is more than welcome.

Thanks

The server is running on a blocking I/O model.

What IP is the client socket connecting to?

Kuphryn

I doing everything on one machine. I'm trying to run both at the same time. Is there any way to make it work?

I finally succeded.

Server.c

Code:

---

#include <stdio.h>
#include <string.h>
#include <winsock2.h>
#define version 0x002
#define MYPORT 3490
#define bufsize 128
int main()
{
        WSADATA wsaData;
        SOCKET socketfd,new_fd;
        struct sockaddr_in my_addr,client_sockaddr;
        char message[bufsize];
        int size;
        if(WSAStartup(MAKEWORD(version,2),&wsaData))
        {
                fprintf(stderr,"\nError intializing winsock library!");
                return 1;
        }
        my_addr.sin_family=AF_INET;
        my_addr.sin_port=htons(MYPORT);
        my_addr.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
        memset(&(my_addr.sin_zero),'\0',8);
       
        socketfd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(socketfd==INVALID_SOCKET)
        {
                fprintf(stderr,"\nError creating socket!");
                return 1;
        }

        if(bind(socketfd,(const struct sockaddr*)&my_addr,sizeof(struct sockaddr))==SOCKET_ERROR)
        {
                fprintf(stderr,"Error binding");
                return 1;
        }

        if(listen(socketfd,5)==SOCKET_ERROR)
        {
                fprintf(stderr,"Error listening!");
                return 1;
        }
       
        while(1)
        {
                int get;

                printf("\nWaiting for data on port TCP: %u\n",MYPORT);
               
                size=sizeof(struct sockaddr);
                new_fd=accept(socketfd,(struct sockaddr*)&client_sockaddr,&size);
                if(new_fd==INVALID_SOCKET)
                {
                        fprintf(stderr,"\nError accepting connection!");
                        return 1;
                }
               
               
                get=recv(new_fd,message,bufsize-1,0);

                if(get==0)
                        break;
                else
                        if(get==SOCKET_ERROR)
                        {
                                fprintf(stderr,"\nError receiving data!");
                                return 1;
                        }
                        else
                        {
                                message[get]=0;
                                fprintf(stdout,"%s ",message);
                        }

        }
        closesocket(new_fd);
        closesocket(socketfd);
        WSACleanup();
}

---

Client.c

Code:

---

#include <stdio.h>
#include <string.h>
#include <winsock2.h>
#define version 0x002
#define SERVERPORT 3490
int main()
{
        WSADATA wsaData;
        SOCKET socketfd;
        struct sockaddr_in server_addr;
        char message[]="Hello FANTA!";
        struct hostent *h;
        if(WSAStartup(MAKEWORD(version,2),&wsaData))
        {
                fprintf(stderr,"\nError intializing winsock library!");
                return 1;
        }

        h=gethostbyname("127.0.0.1");
        server_addr.sin_family=h->h_addrtype;
        server_addr.sin_port=htons(SERVERPORT);
        server_addr.sin_addr.S_un.S_addr=inet_addr(h->h_name);
        memset(&(server_addr.sin_zero),'\0',8);
       
        socketfd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(socketfd==INVALID_SOCKET)
        {
                fprintf(stderr,"\nError creating socket!");
                return 1;
        }

        if(connect(socketfd,(const struct sockaddr*)&server_addr,sizeof(struct sockaddr)))
        {
                fprintf(stdout,"Could not be connected!");
                return 1;
        }
        if(send(socketfd,message,lstrlen(message),0)==SOCKET_ERROR)
        {
                fprintf(stderr,"Data could not be send!");
                return 1;
        }

        closesocket(socketfd);
        WSACleanup();

}

---

I manage to get it work accidentaly.
Changing code in server.c (while(1))
if line is:

Code:

---

h=gethostbyname(INADDR_ANY);

---

which I thought is a good way to obtain host infos, client simply couldn't connect.
then I try not to use hopstent at all an to try with

Code:

---

server_addr.sin_addr.S_un.S_addr=htonl(INADDR_ANY);

---

but that doesn't work either.

It started working only after I put:
h=gethostbyname("127.0.0.1");

I have no experience nor enough knowledge about networks, but as far as I know IP 127.0.0.1 is IP of my computer
when I'm offline and don't have LAN (in that case 192.168...).
So what is the purpose of INADDR_ANY,it seems that is "0.0.0.0" but that is not problem in server.c
In Beej's tutorial I read

Quote:

---

bind(), I should mention that some of the process of getting your own IP address and/or port
can can be automated:
my_addr.sin_port = 0; // choose an unused port at random
my_addr.sin_addr.s_addr = INADDR_ANY; // use my IP address

---

but that makes me problem in client.c

Can you explain me this, or at least recommended some good link.
I'm felling that I'm very close to understand this:)