Hey guys I am trying to write a program which can upload files from my computer to a online server.. I have started with a socket programming client side.....
I have written a code which successfully makes a connection to a server and i can send a message to a server also and can get a reply from it...
Have a look..
#include<stdio.h>
#include<winsock2.h>
#include<bits/stdc++.h>
#include<strings.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
struct sockaddr_in server;
WSADATA wsa;
SOCKET s;
char *message , server_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("172.217.24.238");
server.sin_family = AF_INET;
server.sin_port = htons(80);
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
//Send some data
message = "GET / HTTP/1.1\r\n\r\n";
if( send(s , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
puts("Data Send\n");
//Receive a reply from the server
if((recv_size = recv(s , server_reply , 2000 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("Reply received\n");
//Add a NULL terminating character to make it a proper string before printing
server_reply[recv_size] = '\0';
puts(server_reply);
return 0;
}
Please suggest me how can i modify this to upload a file from my computer to a server whose IP address and port number is known to me.....
PS: I am new to socket programming ....
Please help....
Actual:code which successfully makes a connection to a server and i can send a message to a server also and can get a reply from it...
Expected: Modify to upload some file on server whose ip address and port number is known...
You need to read a bit more from HTTP RFC about posting data to the server.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST
You can get the correct example to learn how to POST the content as the body of HTTP request to the server.
Related
I am trying to implement a unit test to see if using the function "WaitForMultipleObjects" works properly with socket. To do so I implemented a simple UDP server-client protocol. The server bind his socket and wait to receive data from receiver using the function "WaitForMultipleObjects". Once the server receives data from the client, it displays it then waits 5 seconds. The problem here that if the client try to send 2 messages during this five seconds, the first one is displayed while the second one will block the function "WaitForMultipleObjects" forever. I know that I can use the "Select" function to do that since the socket is the only object I am waiting for, but it's just a unit test. In my real project I need to wait on a socket and another object's type which is a windows event (which is of type HANDLE) at the same time. And that's why i am trying to use "WaitForMultipleObjects" on sockets.
Here's the server code:
/*
Simple UDP Server
*/
#include<winsock2.h>
#include<windows.h>
#include <ws2tcpip.h>
#include<stdio.h>
#include<iostream>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
#define BUFLEN 512 //Max length of buffer
#define PORT 8888 //The port on which to listen for incoming data
int main()
{
SOCKET s;
struct sockaddr_in server, si_other;
int slen , recv_len;
char buf[BUFLEN];
WSADATA wsa;
HANDLE SEvent;
slen = sizeof(si_other) ;
//Initialise winsock
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
exit(EXIT_FAILURE);
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_DGRAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( PORT );
//Bind
if( bind(s ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
{
printf("Bind failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
puts("Bind done");
SEvent = WSACreateEvent();
WSAEventSelect( s, SEvent, FD_READ);
//keep listening for data
while(1)
{
printf("Waiting for data...");
fflush(stdout);
//clear the buffer by filling null, it might have previously received data
memset(buf,'\0', BUFLEN);
INT r = WaitForMultipleObjectsEx(1,&SEvent,FALSE,INFINITE,TRUE);
if( r == WAIT_OBJECT_0)
{
if (recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen) == SOCKET_ERROR)
{
printf("recvfrom() failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
//print details of the client/peer and the data received
printf("Received packet from %s:%d\n", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port));
printf("Data: %s\n" , buf);
//now reply the client with the same data
if (sendto(s, buf, recv_len, 0, (struct sockaddr*) &si_other, slen) == SOCKET_ERROR)
{
printf("sendto() failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
ResetEvent(SEvent);
Sleep(5000);
}
else
{
std::cerr<<"WaitForMultipleObject() Error ( "<<GetLastError()<<" )"<<std::endl;
exit(0);
}
}
closesocket(s);
WSACleanup();
return 0;
}
Here's the client code:
/*
Simple udp client
*/
#include<stdio.h>
#include<winsock2.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
#define SERVER "127.0.0.1" //ip address of udp server
#define BUFLEN 512 //Max length of buffer
#define PORT 8888 //The port on which to listen for incoming data
int main(void)
{
struct sockaddr_in si_other;
int s, slen=sizeof(si_other);
char buf[BUFLEN];
char message[BUFLEN];
WSADATA wsa;
//Initialise winsock
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
exit(EXIT_FAILURE);
}
printf("Initialised.\n");
//create socket
if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == SOCKET_ERROR)
{
printf("socket() failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
//setup address structure
memset((char *) &si_other, 0, sizeof(si_other));
si_other.sin_family = AF_INET;
si_other.sin_port = htons(PORT);
si_other.sin_addr.S_un.S_addr = inet_addr(SERVER);
//start communication
while(1)
{
printf("Enter message : ");
gets(message);
//send the message
if (sendto(s, message, strlen(message) , 0 , (struct sockaddr *) &si_other, slen) == SOCKET_ERROR)
{
printf("sendto() failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
//receive a reply and print it
//clear the buffer by filling null, it might have previously received data
/*memset(buf,'\0', BUFLEN);
//try to receive some data, this is a blocking call
if (recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen) == SOCKET_ERROR)
{
printf("recvfrom() failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
puts(buf);*/
}
closesocket(s);
WSACleanup();
return 0;
}
Note: I didn't write all the code. I used a code that was already written (from the internet) but made some changes.
Does anyone know how to fix this problem? (using "WaitForMultipleObjects" on socket properly)
The problem here that if the client try to send 2 messages during this five seconds, the first one is displayed while the second one will clock the function "WaitForMultipleObjects" forever.
Your server code has a race condition.
Your should call WSAResetEvent/ResetEvent before calling recvfrom, not afterwards. Otherwise, there is a possiblity that new data will arrive between the call to recvfrom and WSAResetEvent, setting the event object to signalled. In that case, WSAResetEvent will set the event back to non-signalled, causing you to lose the notification of new data being available.
Also, according to the documentation of WSAEventSelect, after reading data from a socket, if more data is available to be read, the event will automatically be set to signalled again, in order to indicate that more data is available. If you call WSAResetEvent afterwards, then you will set the event back to non-signalled, causing you to lose the notification of new data being available. This is probably the reason for the behavior you describe in the question.
You should rather call WSAResetEvent/ResetEvent immediately after WSAWaitForMultipleEvents/WaitForMultipleObjectsEx. See the documentation for the function WSAWaitForMultipleEvents for a code example (that example uses overlapped I/O instead of WSAEventSelect, though).
Edit: Working on a solution - turns out googling 204.204.204.204 gets me further than more descriptive requests.
Honestly. Wits end. I have no idea how I can spend an entire day doing something that took 10 minutes in Flask (Server) and Javascript (client). I need this to run in C++ and allow a client to connect via BlueStacks' port on the same machine. The client is unimportant because I can't even get that far.
I've tried WinSocks, I've tried WxWidget's networking implementation, I've even tried some random C++ wrapper thing. All of them failed (typically within the EXAMPLE! As in, copy paste and errors everywhere). So I ultimately went back to WinSockets and followed a tutorial on YouTube.
int ServerStuff() {
WSADATA WsData;
WORD ver = MAKEWORD(2, 2);
int wsOK = WSAStartup(ver, &WsData);
if (wsOK != 0) {
wxLogMessage("Can't initialize Winsock! Quitting");
return false;
}
//Create a socket
SOCKET listening = socket(AF_INET, SOCK_STREAM, 0);
if (listening == INVALID_SOCKET) {
wxLogMessage("Can't create a socket! Quitting");
return false;
}
//Bind the ip and port to a socket
sockaddr_in hint;
hint.sin_family = AF_INET;
hint.sin_port = htons(54000);
hint.sin_addr.S_un.S_addr = INADDR_ANY; //Could also use inet_pton
bind(listening, (sockaddr*)&hint, sizeof(hint));
//Tell winsock the socket is for listening
listen(listening, SOMAXCONN);
//Wait for a connection
sockaddr_in client;
int clientSize = sizeof(client);
SOCKET clientSocket = accept(listening, (sockaddr*)&client, &clientSize);
//if (clientSocket == INVALID_SOCKET) {
// wxLogMessage("Client Invalid Socket");
// return false;
//}
char host[NI_MAXHOST]; //Client's remote name
char service[NI_MAXHOST]; //Service (port) the client is connected on
ZeroMemory(host, NI_MAXHOST);
ZeroMemory(service, NI_MAXHOST);
if (getnameinfo((sockaddr*)&client, sizeof(client), host, NI_MAXHOST, service, NI_MAXSERV, 0) == 0) {
wxLogMessage("Can't initialize Winsock! Quitting");
}
else {
inet_ntop(AF_INET, &client.sin_addr, host, NI_MAXHOST);
wxLogMessage(host);
int wut = client.sin_port;
wxString mystring = wxString::Format(wxT("%i"), wut);
wxLogMessage("Connected on port");
wxLogMessage(mystring);
//wxLogMessage(to_string(ntohs(client.sin_port)));
}
wxLogMessage("Got this far somehow");
//Close listening socket - we don't need it anymore - later on we'll learn how to accept multiple client
closesocket(listening);
//while loop: accept and echo message back to client
char buf[4096];
while (true)
{
ZeroMemory(buf, 4096);
//Wait for client to send data
int bytesReceived = recv(clientSocket, buf, 4096, 0);
if (bytesReceived == SOCKET_ERROR) {
//wxLogMessage("ERROR in recv");
break;
}
if (bytesReceived == 0) {
wxLogMessage("Client Disconnected");
break;
}
//Echo back to client
send(clientSocket, buf, bytesReceived + 1, 0);
//Close the socket
closesocket(clientSocket);
//Cleanup winsock
WSACleanup();
wxLogMessage("Welp");
}
}
// event handlers
void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
{
// true is to force the frame to close
ServerStuff();
//Close(true);
}
On the YouTube video ("Creating a TCP Server in C++" - not allowed to post links) this works! The command window opens, is blank infinitely until he connects a client and then the client sends a message and the server replies with the same exact message in return.
Not mine. Mine just rushes through everything and then closes. My log used to immediately quit on the commented code where it states the client socket is invalid so I commented it out. Now my output is:
204.204.204.204
Connected on port
52428
Got this far somehow
I don't know what to do. I'm just trying to send data over a same-machine TCP connection. I'm baffled as to how this is so difficult. It seems like some random process is immediately trying to connect as a client to my server ? But why is it allowed to connect on port 52428 when I'm explicitly hosting on 54000?
My goal:
Start Server
Connect to Server using a Java App within BlueStacks
Send data from Server to Client
It makes more sense for the computer to be the server because there will be multiple BlueStacks instances and I'd prefer to not have to "spawn" multiple programs / servers for what I'm doing.
I see a few mistakes in your socket code.
not calling WSACleanup() if WSAStartup() is successful and then something goes wrong afterwards.
not calling closesocket() if socket() is successful and then something goes wrong afterwards.
not zeroing out the sockaddr_in that you pass to bind(). Random bytes in the struct can cause bind() to fail.
ignoring the return values of bind(), listen(), accept(), and send().
not treating the return value of getnameinfo() correctly. It returns 0 on success, not failure.
sending +1 extra byte back to the client than you received from the client. If the client sends fewer bytes than your buffer can hold, that extra byte would be 0x00 due to your ZeroMemory() call. But if the client actually sends enough bytes to completely fill your buffer, then you would send an extra byte from memory that you do not own. If you really want to send a null terminator after everything you echo, do so explicitly. Otherwise, a true echo server should only send back exactly what it receives, no more, no less.
Try something more like this:
void ServerStuff() {
WSADATA WsData;
int ret = WSAStartup(MAKEWORD(2, 2), &WsData);
if (ret != 0) {
wxLogMessage("Can't initialize Winsock! Error: %d", ret);
return;
}
//Create a socket
SOCKET listening = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (listening == INVALID_SOCKET) {
wxLogMessage("Can't create a socket! Error: %d", WSAGetLastError());
WSACleanup();
return;
}
//Bind the ip and port to a socket
sockaddr_in hint = {};
hint.sin_family = AF_INET;
hint.sin_port = htons(54000);
hint.sin_addr.s_addr = INADDR_ANY; //Could also use inet_pton
ret = bind(listening, (sockaddr*)&hint, sizeof(hint));
if (ret == SOCKET_ERROR) {
wxLogMessage("Can't bind socket! Error: %d", WSAGetLastError());
closesocket(listening);
WSACleanup();
return;
}
//Tell winsock the socket is for listening
ret = listen(listening, SOMAXCONN);
if (ret == SOCKET_ERROR) {
wxLogMessage("Can't listen on socket! Error: %d", WSAGetLastError());
closesocket(listening);
WSACleanup();
return;
}
//Wait for a connection
sockaddr_in client = {};
int clientSize = sizeof(client);
SOCKET clientSocket = accept(listening, (sockaddr*)&client, &clientSize);
if (clientSocket == INVALID_SOCKET) {
wxLogMessage("Can't accept a client! Error: %d", WSAGetLastError());
closesocket(listening);
WSACleanup();
return;
}
char host[NI_MAXHOST] = {}; //Client's remote name
ret = getnameinfo((sockaddr*)&client, sizeof(client), host, NI_MAXHOST, NULL, 0, 0);
if (ret != 0) {
wxLogMessage("Can't get client name info! Error: %d", ret);
inet_ntop(AF_INET, &(client.sin_addr), host, NI_MAXHOST);
}
wxLogMessage("Client: %s, Connected on port: %hu", host, ntohs(client.sin_port));
//Close listening socket - we don't need it anymore - later on we'll learn how to accept multiple client
closesocket(listening);
//while loop: accept and echo message back to client
char buf[4096];
int bytesReceived;
while (true)
{
//Wait for client to send data
bytesReceived = recv(clientSocket, buf, sizeof(buf), 0);
if (bytesReceived == SOCKET_ERROR) {
wxLogMessage("Can't read from client! Error: ", WSAGetLastError());
break;
}
if (bytesReceived == 0) {
wxLogMessage("Client Disconnected");
break;
}
//Echo back to client
ret = send(clientSocket, buf, bytesReceived, 0);
if (ret == SOCKET_ERROR) {
wxLogMessage("Can't send to client! Error: ", WSAGetLastError());
break;
}
}
//Close the socket
closesocket(clientSocket);
//Cleanup winsock
WSACleanup();
wxLogMessage("Welp");
}
I have 2 Computers. My Server is running on the Debian one while my Client is running on the Windows PC.
The IP of my Server is 192.168.2.113, the one of my Client is 192.168.2.122.
When I telnet 127.0.0.1 or 192.168.2.113 on the Server Machine there is no problem.
The Problem is that I cant connect to the Server from my Client.
I opened the port 50002 via iptables with the comment:
sudo iptables -A INPUT -p tcp --dport 50002 --jump ACCEPT
The main.cpp of my Server:
#include<stdio.h>
#include<string.h> //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h> //write
int main(int argc , char *argv[])
{
int socket_desc , client_sock , c , read_size;
struct sockaddr_in server , client;
char client_message[2000];
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
puts("Socket created");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 50002 );
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
//print the error message
perror("bind failed. Error");
return 1;
}
puts("bind done");
//Listen
listen(socket_desc , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
//accept connection from an incoming client
client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c);
if (client_sock < 0)
{
perror("accept failed");
return 1;
}
puts("Connection accepted");
//Receive a message from client
while( (read_size = recv(client_sock , client_message , 2000 , 0)) > 0 )
{
//Send the message back to client
write(client_sock , client_message , strlen(client_message));
}
if(read_size == 0)
{
puts("Client disconnected");
fflush(stdout);
}
else if(read_size == -1)
{
perror("recv failed");
}
return 0;
}
Something strange i noticed is that I can connect to www.google.com in firefox but not in telnet (on my client pc):
telnet>o www.google.com 80
I only get 400-badrequest error
help is very appriciated.
Suggestions:
Step 1) establish that you can ping your server from windows. This way we eliminate potential network configuration issues. Make changes to your firewall if needed.
ping 192.168.2.113
Step 2) Ping from server to access windows. Windows firewall can prevent communication as well.
ping 192.168.2.112
Step 3) I compiled your server program and run om Debian server.
Your program works as expected.
First I connected with telnet on same server to test the program. All good
Step 4) I used telnet from Windows 10 to connect to your server. It connected as well, sending encoded data back.
Step 5) I used PuTTY telnet from Windows that worked good as expected.
Step 6) Conclusion that you have network configuration problem on your system that is not your program related. It can be firewall as well. start with step 1 and 2. Then if needed troubleshoot your network. Regards Bogdan.
i have problem because my server dont get UDP data. Ports on router are forwarded, data income to local-server network (it is visible on sniffer (3) ) but server dont receive it.
Server and server network screen
You can see 1 and 2 TCP packets correct income to server on connected sockets. But my client then send UDP data to server and data enter to local-server network (see that sniffer detect it on 3) but server dont take it.
Here is code of client:
struct sockaddr_in si_other;
int s, slen = sizeof(si_other);
char buf[10];
char message[10];
WSADATA wsa;
//Initialise winsock
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
{
printf("Failed. Error Code : %d", WSAGetLastError());
exit(EXIT_FAILURE);
}
printf("Initialised.\n");
//create socket
if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == SOCKET_ERROR)
{
printf("socket() failed with error code : %d", WSAGetLastError());
exit(EXIT_FAILURE);
}
//setup address structure
memset((char *)&si_other, 0, sizeof(si_other));
si_other.sin_family = AF_INET;
si_other.sin_port = htons(14996);
si_other.sin_addr.S_un.S_addr = inet_addr(server ip);
memcpy(message, "cokolwiek", 8);
//send the message
if (sendto(s, message, strlen(message), 0, (struct sockaddr *) &si_other, slen) == SOCKET_ERROR)
{
printf("sendto() failed with error code : %d", WSAGetLastError());
exit(EXIT_FAILURE);
}
But its not problem with client. Here is server code but i think it is also correct:
SOCKET s;
struct sockaddr_in server, si_other;
int slen, recv_len;
char buf[10];
WSADATA wsa;
slen = sizeof(si_other);
//Initialise winsock
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
{
printf("Failed. Error Code : %d", WSAGetLastError());
exit(EXIT_FAILURE);
}
printf("Initialised.\n");
//Create a socket
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == INVALID_SOCKET)
{
printf("Could not create socket : %d", WSAGetLastError());
}
printf("Socket created.\n");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(14996);
//Bind
if (::bind(s, (struct sockaddr *)&server, sizeof(server)) == SOCKET_ERROR)
{
printf("Bind failed with error code : %d", WSAGetLastError());
exit(EXIT_FAILURE);
}
puts("Bind done");
//blocking on it, waiting for data
if ((recv_len = recvfrom(s, buf, 10, 0, (struct sockaddr *) &si_other, &slen)) == SOCKET_ERROR)
{
printf("recvfrom() failed with error code : %d", WSAGetLastError());
exit(EXIT_FAILURE);
}
//print details of the client/peer and the data received
printf("Received packet from %s:%d\n", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port));
printf("Data: %s\n", buf);
Some description that may help - main server loop is select() and when client ask for order, server send order back to client and starts proceeding command.
server:
while (1) {
select()
if (socket is in FD_SET)
get data, send it back and handleCommand()
}
handleCommand() {
tcp data exchange
wait for udp packet - it fail
}
client:
sendCommand()
//another receiving commands thread
while (recv) {
handle command
tcp data exchange
send udp data
}
Pls dont give me answears to do it in another wait. I need to punch hole for NAT Traversal. What problem is that? Another listener grabbing my data? But netstat -nop UDP -a didn't give information that something other is listening, and bind socket didn't failed. Also another important information That code work on the begining of program, i mean server receive data but later not.
Okey, so as ElderBug said
Are you sure you setup the UDP server socket before you send the data ? It's not clear in your question
Yep, it was my fault. The miniseconds decided that sending data on one machine was executed before setting up listener on server. Thank you for answer.
But i dont exactly understand the problem. Shouldn't that data income to receive buffer and wait for "grabbing" it by recvfrom function?
I need to communicate between two systems on local server. So, I decided to use "Socket" programming in C++. For this I follow this tutorial. I make some changes according to my need like changing port no, IP etc which are working fine. Now the problem is I can send data from Server to Client but I am unable to receive any data from Client to Server.
Here is my code for Client:-
int main()
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char *message , server_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("192.168.1.4");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
if((recv_size = recv(s , server_reply , 2000 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("Reply received\n");
server_reply[recv_size] = '\0';
puts(server_reply);
message = "Cleint says:- I am Client";
if( send(s , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
puts("sending data complete\n");
system("pause");
return 0;
}
Here is My code for Server:-
int main()
{
WSADATA wsa;
SOCKET s , new_socket;
struct sockaddr_in server , client;
int c;
char *message , cleint_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
//Bind
if( bind(s ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
{
printf("Bind failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
puts("Bind done");
//Listen to incoming connections
listen(s , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while( (new_socket = accept(s , (struct sockaddr *)&client, &c)) != INVALID_SOCKET )
{
puts("Connection accepted");
//Reply to the client
message = "Server sends:- I am Server\n";
send(new_socket , message , strlen(message) , 0);
while(1)
{
if((recv_size = recv(s , cleint_reply , 2000 , 0)) == SOCKET_ERROR)
{
// puts("recv failed");
}
else
puts("data received");
}
}
if (new_socket == INVALID_SOCKET)
{
printf("accept failed with error code : %d" , WSAGetLastError());
return 1;
}
closesocket(s);
WSACleanup();
return 0;
}
This is the console messages I am getting on Client:-
Initialising Winsock...
Initialised
Connected
Server sends:- I am server
Sending Data complete
Press any key to continue
And these are the messages I am getting on Server console:-
Initialising Winsock...
Socket Created
Bind Done
Waiting for incoming connections..
Connection accepted
So, please tell we why my server is not able to receive any thing...
Found the error.
Once you use accept() you have a new file descriptor which you need to use send and receive data [lets say for that specific CLIENT].
The accept() function shall extract the first connection on the queue of pending connections, create a new socket with the same socket type protocol and address family as the specified socket, and allocate a new file descriptor for that socket.
In your server when you get a new connection you correctly use new file descriptor recv_size to send data but you do not use that new connection's file descriptor to receive data.
Wrong code line
if((recv_size = recv(s , cleint_reply , 2000 , 0)) == SOCKET_ERROR)
Correction
if((recv_size = recv(new_socket , cleint_reply , 2000 , 0)) == SOCKET_ERROR)
this should work now