C++ Socket Receiving Erroneous Commands, not intended ones - c++

Question

I am learning socket programming for use in an upcoming project, and I have researched the issue pretty extensively. Basically, all this program needs to is on a client computer (locally, i.e. my computer) needs to connect to a remote server and send a command (which it has done, I have gotten it to read back Apache server stats to me).
What is happening is this: I believe I have the socket set right, but the server receives random garbage buffers (one of which consisted of " '>Z"). I have tried various socket settings, different bindings, etc.
I have in the process of starting it will initialize winsock, create a socket, bind the network, and then do a listen loop and while(1) recv data.
I have yet to get the server (on a remote computer, hosted at a datacenter) to output the message. This is my only goal for the time being. I appreciate everyone's help in advance, and the code is before (this is the entire code, sorry for the length).
Client Code:
char *host = "127.0.0.1";
SOCKET clientsock;
struct sockaddr_in server_address;
struct hostent *host_info;
WSADATA WSAData;
if(WSAStartup(MAKEWORD(2,2), &WSAData) != -1) {
cout << "WINSOCK2 Initialized" << endl;
if((clientsock = socket(AF_INET, SOCK_STREAM, 0)) != SOCKET_ERROR) {
cout << "Socket Created" << endl;
char opt[2];
opt[0] = 0;
opt[1] = 1;
//setsockopt(clientsock, SOL_SOCKET, SO_BROADCAST, opt, sizeof(opt));
host_info = gethostbyname(host);
server_address.sin_family = AF_INET;
server_address.sin_addr = *((struct in_addr *)host_info->h_addr);
server_address.sin_port = htons(80);
if(connect(clientsock, (struct sockaddr *)&server_address, sizeof(struct sockaddr)) == 0) {
cout << "Connected to host" << endl;
char COMMAND[22] = "SVR --WINSOCK-VERIFY\0";
if(send(clientsock, COMMAND, sizeof(COMMAND), 0)) {
cout << "Command Sent" << endl;
closesocket(clientsock);
}
else {
cout << "ERROR - Could not send command. " << "Error: " << WSAGetLastError() << endl;
closesocket(clientsock);
WSACleanup();
}
}
else {
cout << "ERROR - Could not connect to host. " << "Error: " << WSAGetLastError() << endl;
closesocket(clientsock);
WSACleanup();
}
}
else {
cout << "ERROR - Could not create the socket. " << "Error: " << WSAGetLastError() << endl;
WSACleanup();
}
}
else {
cout << "ERROR - Could not initialize WINSOCK2. " << "Error: " << WSAGetLastError() << endl;
WSACleanup();
}
Server Code:
SOCKET serversock;
char *server = "127.0.0.1";
//char *server = "50.31.1.180";
struct sockaddr_in server_address;
WSADATA WSAData;
if(WSAStartup(MAKEWORD(2,2), &WSAData) != -1) {
cout << "WINSOCK2 Initialized" << endl;
if((serversock = socket(PF_INET, SOCK_DGRAM, PF_UNSPEC)) != SOCKET_ERROR) {
cout << "Socket Created" << endl;
unsigned long NB = 1;
ioctlsocket(serversock, FIONBIO, &NB);
server_address.sin_family = AF_INET;
server_address.sin_addr = *((struct in_addr *)server);
server_address.sin_port = htons(21578);
if(bind(serversock, (struct sockaddr*)&server_address, sizeof(struct sockaddr) == 0)) {
cout << "Network bound" << endl;
cout << "Listening..." << endl;
listen(serversock, 5);
while(1) {
int size = sizeof((struct sockaddr *)server);
SOCKET clientsock = accept(serversock, (struct sockaddr *)server, &size);
char INCOMMAND[20];
if(clientsock >= 0) {
if(recv(clientsock, INCOMMAND, sizeof(INCOMMAND), 0)) {
int i = 0;
if(INCOMMAND == "SVR --WINSOCK-VERIFY\0") {
cout << "SVR receieved" << endl;
}
while(INCOMMAND[i] != '\0') {
cout << INCOMMAND[i];
i++;
}
cout << endl;
}
else {
cout << "ERROR - Could not receive command" << endl;
break;
}
}
}
}
else {
cout << "ERROR - Could not bind network. " << "Error: " << WSAGetLastError() << endl;
closesocket(serversock);
WSACleanup();
}
}
else {
cout << "ERROR - Could not create the socket. " << "Error: " << WSAGetLastError() << endl;
WSACleanup();
}
}
else {
cout << "ERROR - Could not initialize WINSOCK2. " << "Error: " << WSAGetLastError() << endl;
WSACleanup();
}

Answer 1

Calls to send/recv may not send/receive the amount of bytes you indicate in their third argument, in fact, most of the time they will send/receive less bytes than you expect. You usually have to loop until the entire data has been sent/received. Also note that doing this:
char buffer[100];
recv(clientsock, buffer, sizeof(buffer), 0);
cout << buffer;
Will most surelly print garbage, since you don't have a null terminator in your char array(whatch out for buffer overflows when appending it), and you're not checking the return value of recv. It might be reading 1 byte only(or none if an error ocurred). You're printing your buffer the same way in your server app.
In this case, you are actually sending the null-terminator, but since you might read less bytes than you expect, this character might not be received by the other application, thus printing it will print garbage chars.
Edit: You should have a look at the structure of a sockaddr struct. You can have a look at it here. In your code you are using this convertion:
int size = sizeof((struct sockaddr *)"127.0.0.1");
const char *, which is the type of "127.0.0.1", cannot be casted to a sockaddr pointer, they're incompatible. Here you should use getaddrinfo in order to resolve the IP address(note that you could use a domain name, and this function would resolve it). There are lots of tutorials online on how to use this function, just search for "getaddrinfo".