Connecting to local virtual machine - c

Question

I suspect this has an easy solution I'm overlooking, probably to do with the client or how this is set up.
Anyways, I'm trying to set up a simple Echo server/client to understand the basics of socket programming. I have a virtual machine running Linux Mint, and the host is running Windows 10. The virtual machine I am setting to run the server c code, and the Windows will be running the client.
I started off making the server code
//Echo Server for UNIX: Using socket programming in C, a client sends a string
//to this server, and the server responds with the same string sent back to the client
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
int main()
{
char stringBuffer[50]; //string buffer for reading incoming and resending
int listener, communicator, c; //store values returned by socket system call
if((listener = socket(AF_INET, SOCK_STREAM, 0)) == -1) //creates a new socket
puts("Could not create socket");
puts("Socket Created");
struct sockaddr_in servAddr, client; //structure from <netinet/in.h> for address of server
servAddr.sin_family = AF_INET; //addressing scheme set to IP
servAddr.sin_port = htons(8888); //server listens to port 5000
servAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); //symbolic constant of server IP address
//binds the socket to the address of the current host and port# the server will run on
if (bind(listener, (struct sockaddr *) &servAddr, sizeof(servAddr)) < 0){
puts("Bind failed");
return 1;
}
puts("Bind Successful");
listen(listener, 5); //listens for up to 5 connections at a time
c = sizeof(struct sockaddr_in);
if ((communicator = accept(listener, (struct sockaddr*)&client, (socklen_t*)&c ))<0)
puts("accept failed");
puts("Connection Accepted");
//wait until someone wants to connect, then whatever is sent can be read from communicator, which can then be sent back
while(1){
bzero(stringBuffer, 50); //sets buffer to 0
read(communicator, stringBuffer, 50); //reads from communicator into buffer
write(communicator, stringBuffer, strlen(stringBuffer)+1); //returns back
}
return 0;
}
after that I tested it out by opening another terminal in the guest machine and typed "telnet localhost 8888" and input whatever strings I wanted.
This test worked so now, onto my Windows machine to create the client side of the socket programming:
#include <winsock.h>
#include <stdio.h>
#include <string.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc, char *argv[])
{
WSADATA wsadata; //variable for using sockets in windows
SOCKET sock; //socket variable for network commands
char sendString[50], recieveString[50]; //variables for sending and recieving messages to/from server
//check if WSA initialises correctly
if (WSAStartup(MAKEWORD(2,2), &wsadata) != 0)
printf("Error Code: %d", WSAGetLastError());
//creates new socket and saves into sock
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
printf("Could not create socket: %d", WSAGetLastError());
printf("Socket created\n");
struct sockaddr_in servAddr;
servAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); //sets the IP address to the same machine as the server
servAddr.sin_family = AF_INET; //addressing scheme set to TCP/IP
servAddr.sin_port = htons(8888); //server address is on port 8888
//connects to device with specifications from servAddr
if (connect(sock, (struct sockaddr *)&servAddr, sizeof(servAddr)) < 0) {
printf("Connection Error %d\n", WSAGetLastError());
return 1;
}
printf("Connection Accepted\n");
while(1){
fgets(sendString, 50, stdin); //uses stdin to get input to put into sendString
//sends sendString to server using sock's properties
if (send(sock, sendString, strlen(sendString) + 1, 0) < 0); {
printf("Send Failed");
return 0;
}
//reads from server into recieveString
if ((recv(sock, recieveString, 50, 0)) == SOCKET_ERROR)
printf("Recieve Failed");
printf("%s", recieveString); //prints out recieveString
}
}
Now, with the server still running, when I try out the client-side, I get the response "Connection Error" (from line 35). Having looked at both Unix and WinSock examples, I'm unsure as to why I would be failing the connection. I suspect it might have something to do with a windows to linux VM but I'm not sure.
---UPDATE---
Having updated the accidental semicolon and added the WSAGetLastError, it's showing an error code of 10061; This translates to
"Connection refused.
No connection could be made because the target computer actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host—that is, one with no server application running."

Answer 1

[after the 3rd edit:]
Sry, just re-read your question. The important thing is here:
The virtual machine I am setting to run the server c code, and the Windows will be running the client.
127.0.0.1 is an address always only local to an IP enabled box. So you your server is listening on the interface 127.0.0.1 local to the Linux VM and the client tries to connect to 127.0.0.0 local to the Windows box. Those two interfaces are not the same. The result is the obvious, namely the client does not find anything to connect to.
127.0.0.1 (the so called "IPv4 local loopback interface") can only be used for connections local to exactly one box.

Answer 2

if (connect(sock, (struct sockaddr *)&servAddr, sizeof(servAddr)) < 0); {
printf("Connection Error");
return 1;
}
This is just a trivial syntax mistake. You are entering the block unconditionally. Remove the first semicolon.
However there is a much more important point to be made. When you get an error from a system call such as connect(), you must print the error. Not just some message of your own devising. Otherwise you don't know whether you simply have a bug, or a temporary problem, or a long-lasting problem, or a permanent problem.
Change the printf() to:
printf("Connect error %s\n", WSAGetLastError());
and then don't continue as though the error didn't happen.
Note that this applies to all system calls, specifically including socket(), bind(), listen(), connect(), accept(), recv(), send(), and friends.