I'm writing a tcp proxy and while it seem to work it leaves a memory leak behind. I manipulated the code to forward the incoming packet to itself to create 10000 sockets and close them to see where the leak is. However I can't figure it out. I've used deleaker and it doesn't shows any leak(besides a small one that I don't care.)
But then I untick the two boxes and this comes out.
Any help would be appreciated!
Code:
#include <winsock2.h>
#include <stdio.h>
#include <windows.h>
#include <ws2tcpip.h>
#include <tchar.h>
#include <process.h> /* _beginthread() */
// Need to link with Ws2_32.lib
#pragma comment(lib, "Ws2_32.lib")
#define PORT "1234" /* Port to listen on */
#define BUF_SIZE 4096 /* Buffer for transfers */
typedef struct {
char *host;
char *port;
SOCKET sock;
}
HandleStruct;
unsigned int S2C(SOCKET from, SOCKET to)
{
char buf[BUF_SIZE];
unsigned int disconnected = 0;
size_t bytes_read, bytes_written;
bytes_read = recv(from, buf, BUF_SIZE, 0);
if (bytes_read == 0) {
disconnected = 1;
}
else {
bytes_written = send(to, buf, bytes_read, 0);
if (bytes_written == -1) {
disconnected = 1;
}
}
return disconnected;
}
unsigned int C2S(SOCKET from, SOCKET to)
{
char buf[BUF_SIZE];
unsigned int disconnected = 0;
size_t bytes_read, bytes_written;
bytes_read = recv(from, buf, BUF_SIZE, 0);
if (bytes_read == 0) {
disconnected = 1;
}
else {
bytes_written = send(to, buf, bytes_read, 0);
if (bytes_written == -1) {
disconnected = 1;
}
}
return disconnected;
}
void handle(void *param)
{
HandleStruct *args = (HandleStruct*) param;
SOCKET client = args->sock;
const char *host = args->host;
const char *port = args->port;
SOCKET server = -1;
unsigned int disconnected = 0;
fd_set set;
unsigned int max_sock;
struct addrinfo *res = NULL;
struct addrinfo *ptr = NULL;
struct addrinfo hints;
/* Get the address info */
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
if (getaddrinfo(host, port, &hints, &res) != 0) {
perror("getaddrinfo");
closesocket(client);
return;
}
/* Create the socket */
server = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (server == INVALID_SOCKET) {
perror("socket");
closesocket(client);
return;
}
/* Connect to the host */
if (connect(server, res->ai_addr, res->ai_addrlen) == -1) {
perror("connect");
closesocket(client);
return;
}
if (client > server) {
max_sock = client;
}
else {
max_sock = server;
}
/* Main transfer loop */
while (!disconnected) {
FD_ZERO(&set);
FD_SET(client, &set);
FD_SET(server, &set);
if (select(max_sock + 1, &set, NULL, NULL, NULL) == SOCKET_ERROR) {
perror("select");
break;
}
if (FD_ISSET(client, &set)) {
disconnected = C2S(client, server);
}
if (FD_ISSET(server, &set)) {
disconnected = S2C(server, client);
}
}
closesocket(server);
closesocket(client);
fprintf(stderr, "Sockets Closed: %d/%d", server, client);
_endthread();
return;
}
int _tmain(int argc)
{
WORD wVersion = MAKEWORD(2, 2);
WSADATA wsaData;
int iResult;
SOCKET sock;
struct addrinfo hints, *res;
int reuseaddr = 1; /* True */
/* Initialise Winsock */
if (iResult = (WSAStartup(wVersion, &wsaData)) != 0) {
fprintf(stderr, "WSAStartup failed: %dn", iResult);
return 1;
}
char * host = "127.0.0.1";
char * port = "1234";
/* Get the address info */
ZeroMemory(&hints, sizeof hints);
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
if (getaddrinfo(NULL, PORT, &hints, &res) != 0) {
perror("getaddrinfo");
WSACleanup();
return 1;
}
/* Create the socket */
sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sock == INVALID_SOCKET) {
perror("socket");
WSACleanup();
return 1;
}
/* Enable the socket to reuse the address */
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuseaddr,
sizeof(int)) == SOCKET_ERROR) {
perror("setsockopt");
WSACleanup();
return 1;
}
/* Bind to the address */
if (bind(sock, res->ai_addr, res->ai_addrlen) == SOCKET_ERROR) {
perror("bind");
WSACleanup();
return 1;
}
/* Listen */
if (listen(sock, 6500) == SOCKET_ERROR) {
perror("listen");
WSACleanup();
return 1;
}
freeaddrinfo(res);
int i = 0;
HandleStruct *arg;
arg = (HandleStruct *)malloc(sizeof( HandleStruct));
/* Main loop */
while(1) {
int size = sizeof(struct sockaddr);
struct sockaddr_in their_addr;
SOCKET newsock;
ZeroMemory(&their_addr, sizeof (struct sockaddr));
newsock = accept(sock, (struct sockaddr*)&their_addr, &size);
if (newsock == INVALID_SOCKET) {
perror("acceptn");
}
else {
arg->sock = newsock;
arg->host = host;
arg->port = port;
if (i < 10000) {
_beginthread(handle, 0, (void*) arg);
i++;
}
}
}
closesocket(sock);
WSACleanup();
return 0;
}
I'm not familiar with reading the program in the screenshots you posted; however, you should probably be concerned about this line:
arg = (HandleStruct *)malloc(sizeof( HandleStruct));
Here you are allocating memory for a HandleStruct via malloc() which doesn't appear to be cleaned up anywhere with a subsequent call to free(). You pass arg into handle() but still don't deallocate the memory.
It doesn't appear to be handle()'s responsibility to clean arg up, so you should probably have a call to free() after the while loop, or you could allocate the HandleStruct at the beginning of each loop and deallocate it at the end.
Or you could save yourself the hassle and use std::unique_ptr, and optionally change your threads to std::thread, which self-documents who owns the memory etc:
void handle(std::unique_ptr<HandleStruct> args)
{
// Manipulate args
...
}
int main()
{
std::unique_ptr<HandleStruct> pHandle = std::make_unique<HandleStruct>();
for (;;)
{
...
pHandle->sock = newsock;
pHandle->host = host;
pHandle->port = port;
// Create thread:
std::thread t(&handle, pHandle);
// Wait for thread to finish so pHandle doesn't change while we are using it on another thread
// t.join();
}
}
Every socket uses some memory in the operating system.
Here the description in Linux : accept
ENOBUFS, ENOMEM
Not enough free memory. This often means that the memory
allocation is limited by the socket buffer limits, not by the
system memory.
The OS might not clean them up.
You are also trying to create 10000 threads, these might also take some memory, if the creation doesn't fail long before with errno set to EAGAIN.
I'm writing a server in C++ on windows. On connection, the server creates two threads to handle the request - one constantly reading the input from the socket and the second constantly writes output to it. I'm experiencing problems with it because when there's no input from the client but output to send to it thread #1 is blocking on recv() making thread two block on send() and not write it's data.
Is there a way to send() to a socket although it is already in blocking recv()?
Thanks
EDIT:
I took out the relevant code and reproduced the issue. if I comment out the AfxThreadCall to the readThread, the data is being sent. otherwise it isn't. the client is a simple client that prints what it recieves.
SOCKET m_sockIOSrv = NULL;
SOCKET m_sockIO = NULL;
UINT readThread(LPVOID args)
{
WSABUF DataBuf;
DWORD RecvBytes;
DWORD Flags = 0 ;
char buf[4096];
DataBuf.len = 4096;
DataBuf.buf = buf;
while (true)
{
int ret = WSARecv(m_sockIO, &DataBuf, 1, &RecvBytes, &Flags, NULL, NULL); // Read some data...
if (ret == SOCKET_ERROR)
{
printf("ERROR: WSARecv: %d", WSAGetLastError());
return 1;
}
printf("jobleader - got %d from recv\n", RecvBytes);
}
return 0;
}
UINT writeThread(LPVOID args)
{
WSABUF DataBuf;
DWORD SendBytes;
DWORD Flags;
char buf[] = { 'a', 'a', 'a' };
DataBuf.len = 3;
DataBuf.buf = buf;
while (true)
{
DWORD dwWritten;
WSASend(m_sockIO, &DataBuf, 1, &dwWritten, 0, NULL, NULL);
}
return 0;
}
SOCKET ServerSocket(unsigned int & port) {
// Our server socket
SOCKET s = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, 0);
if (s == INVALID_SOCKET)
return s;
SOCKADDR sa;
sa.sa_family = AF_INET;
memset(sa.sa_data, 0, sizeof(sa.sa_data));
if (bind(s, &sa, sizeof(sa))) {
closesocket(s);
return INVALID_SOCKET;
}
struct sockaddr_in sa_in;
int sz = sizeof(sa_in);
if (getsockname(s, (struct sockaddr *)&sa_in, &sz)) {
closesocket(s);
return INVALID_SOCKET;
}
if (listen(s, 50)) {
closesocket(s);
return INVALID_SOCKET;
}
port = ntohs(sa_in.sin_port);
return s;
}
int _tmain(int argc, _TCHAR* argv[])
{
unsigned int ioPort = 0;
WORD wVersionRequested = MAKEWORD(2, 2);
WSADATA wsaData;
if (WSAStartup(wVersionRequested, &wsaData))
{
if (!AfxSocketInit())
{
printf("ERROR: Unable to initialize WinSock DLL");
exit(2);
}
}
m_sockIOSrv = ServerSocket(ioPort);
if (m_sockIOSrv == INVALID_SOCKET) {
int lastError = GetLastError();
printf("ERROR: StartIOSockets Failed to start socket %d.\n",lastError);
return 1;
}
printf("Listening on %d\n", ioPort);
m_sockIO = accept(m_sockIOSrv, NULL, NULL);
AfxBeginThread(&readThread, (LPVOID)NULL);
AfxBeginThread(&writeThread, (LPVOID)NULL);
getchar();
}
So I have a winsock application in which the computer tries to accept a client, and then starts a new thread with the a pointer to the class object with client info which it copies and then deletes with the delete keyword.
The backbone is copied but the beginning of the OOP-structure is my work and the current implementation seems to be giving me some issues.
I noticed the socket might not copy in the correct format, but have no idea on how to fix this. As the client tries to connect it throws me the error message of that the server refused the connection. Anyway, here is the code of the server.
UPDATE:
It's working.
// main.h
#pragma once
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <process.h>
#include <cstring>
#include <iostream>
#include <stdio.h>
#include <memory>
#pragma comment(lib,"ws2_32.lib" )
class clientData{
private:
SOCKET clientSocket;
std::string name;
public:
clientData(SOCKET &clientSock, const char *tName);
clientData(clientData *cliDat);
~clientData();
inline SOCKET *getClientSocket(){
return &clientSocket;
}
inline std::string *getName(){
return &name;
}
};
And here is the main cpp file
// main.cpp
#include "main.h"
unsigned int __stdcall ServClient(void *data);
int main(int argc, char *argv[])
{
WSADATA wsaData;
int iResult;
sockaddr_in addr;
SOCKET sock, client[10];
addr.sin_family = AF_INET;
addr.sin_port = htons(13337);
addr.sin_addr.S_un.S_addr = INADDR_ANY;
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);//2.2
if (iResult)
{
printf("WSA startup failed");
return 0;
}
sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock == INVALID_SOCKET)
{
printf("Invalid socket");
return 0;
}
int addrlen = sizeof(sockaddr_in);
iResult = bind(sock, (sockaddr*)&addr, sizeof(sockaddr_in));
if (iResult)
{
printf("bind failed %u", GetLastError());
return 0;
}
iResult = listen(sock, SOMAXCONN);
if (iResult)
{
printf("iResult failed %u", GetLastError());
return 0;
}
int iterationCount = 0;
while ((iterationCount < 10 &&
(client[iterationCount] = accept(sock, (SOCKADDR*)&addr, &addrlen)) != SOCKET_ERROR))
{
if (client[iterationCount] == INVALID_SOCKET){
printf("invalid client socket",GetLastError());
continue;
}
++iterationCount;
char tempName[100] = { '\0' };
sprintf_s(tempName, sizeof(tempName), "Client %u", iterationCount);
clientData *tempCLdata = new clientData(client[iterationCount - 1], tempName);
_beginthreadex(0, 0, ServClient, (void*)tempCLdata, 0, 0);
tempCLdata = nullptr;
}
return 0;
}
unsigned int __stdcall ServClient(void *data)
{
clientData cliDat((clientData*)data);
delete (clientData*)data;
printf("Client connected\n");
int recvLen = 1;
char chunk[1024] = { '\0' };
while ((recvLen = recv(*cliDat.getClientSocket(), chunk, 1024, 0)) > 0){
printf("%.*s", recvLen, chunk);
}
if (recvLen == -1)
perror("Socket recv() problem..\n");
else
printf("End of data on socket, closing..\n");
closesocket(*cliDat.getClientSocket());
return 0;
}
clientData::clientData(SOCKET &clientSock, const char *tName){
clientSocket = clientSock;
name.assign(tName);
}
clientData::clientData(clientData *cliDat){
SOCKET *clientSocketPtr = cliDat->getClientSocket();
clientSocket = *clientSocketPtr;
name.assign(cliDat->getName()->c_str());
}
clientData::~clientData(){
}
Also here is the relevant bit of client code, as requested.
char buffer[1023] = { '\0' };
int heartbeatCount = 0;
while (true)
{
sprintf_s(buffer, sizeof(buffer), "Heartbeat %d", heartbeatCount + 1);
send(sock, buffer, strlen(buffer) + 1, 0);
++heartbeatCount;
Sleep(1000);
}
I’ve recently started learning IOCP on Windows and been reading the following article:
http://www.codeproject.com/Tips/95363/Another-TCP-echo-server-using-IOCP
You can download the sample for the article from:
http://dl.dropbox.com/u/281215/documentation/iocp-1.00.html
The sample contains two simple applications – iocp_echo_server and TcpEchoClient.
I understand that IOCP is usually used on the server side of the client/server model but I’d like to create a client using IOCP.
I’ve so far tried modifying the client sample above so that whenever the server sends a response to the client, it gets picked up automatically, however it doesn’t work.
I’ve left iocp_echo_server.c as is. My modified version of TcpEchoClient.c looks like:
//TcpEchoClient.c - a minimalistic echo client
// -----------------------------------------------------------------------------
// C language includes
#include <stdio.h>
#include <winsock2.h>
#include "mswsock.h" // for AcceptEx
#include <stdlib.h> // exit
#include <string.h>
// Windows includes
#include <windows.h>
#pragma warning(disable: 4996) // sprintf
// -----------------------------------------------------------------------------
// configuration
enum
{
BUFLEN = 1000,
SERVICE_PORT = 4000,
SERVER_ADDRESS = INADDR_LOOPBACK
};
enum // socket operations
{
OP_NONE,
OP_ACCEPT,
OP_READ,
OP_WRITE
};
typedef struct _SocketState // socket state & control
{
char operation;
SOCKET socket;
DWORD length;
char buf[1024];
} SocketState;
// variables
static HANDLE cpl_port;
static SOCKET sock;
static SocketState sock_state;
static WSAOVERLAPPED sock_ovl;
static LPFN_ACCEPTEX pfAcceptEx;
static GUID GuidAcceptEx = WSAID_ACCEPTEX;
static int msgNumber;
static char msgBuf[BUFLEN];
static struct sockaddr_in sin;
// prototypes
static void createConnection(void);
static void createSocket(void);
static void init(void);
static void initWinsock(void);
static void prepareEndpoint(void);
static void recvBuffer(void);
static void run(void);
static void sendBuffer(void);
static SOCKET create_accepting_socket(void);
static void create_io_completion_port(void);
static BOOL get_completion_status(DWORD*, SocketState**,WSAOVERLAPPED**);
// -----------------------------------------------------------------------------
void main(void)
{
init();
run();
}
// -----------------------------------------------------------------------------
static void createConnection(void)
{
printf("* connecting\n");
if (WSAConnect(sock, (LPSOCKADDR)&sin, sizeof(sin), NULL, NULL, NULL, NULL) == SOCKET_ERROR)
{
int err = WSAGetLastError();
printf("* error %d in connect\n", err);
exit(1);
}
printf("* connected\n");
}
// -----------------------------------------------------------------------------
static void createSocket(void)
{
sock = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
if (sock == INVALID_SOCKET)
{
int err = WSAGetLastError();
printf("* error %d creating socket\n", err);
exit(1);
}
// for use by AcceptEx
sock_state.socket = 0; // to be updated later
sock_state.operation = OP_ACCEPT;
if (CreateIoCompletionPort((HANDLE)sock, cpl_port, (ULONG_PTR)&sock_state, 0) != cpl_port)
{
int err = WSAGetLastError();
printf("* error %d in listener\n", err);
exit(1);
}
}
// -----------------------------------------------------------------------------
static void init(void)
{
initWinsock();
create_io_completion_port();
createSocket();
prepareEndpoint();
createConnection();
}
// -----------------------------------------------------------------------------
static void initWinsock(void)
{
WSADATA wsaData;
if (WSAStartup(0x202, &wsaData) == SOCKET_ERROR)
{
int err = WSAGetLastError();
printf("* error %d in WSAStartup\n", err);
exit(1);
}
}
// -----------------------------------------------------------------------------
static void prepareEndpoint(void)
{
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl(SERVER_ADDRESS);
sin.sin_port = htons(SERVICE_PORT);
// bind_listening_socket()
{
//if (bind(sock, (SOCKADDR*)&sin, sizeof(sin)) == SOCKET_ERROR)
//{
// printf("* error in bind!\n");
// exit(1);
//}
}
// start_listening()
{
//if (listen(sock, 100) == SOCKET_ERROR)
//{
// printf("* error in listen!\n");
// exit(1);
//}
//printf("* started listening for connection requests...\n");
}
// load_accept_ex()
{
//DWORD dwBytes;
// black magic for me!!!
// You do not need to call in your code WSAIoctl. You can directly use AcceptEx and adds Mswsock.lib.
//WSAIoctl(sock, SIO_GET_EXTENSION_FUNCTION_POINTER, &GuidAcceptEx, sizeof(GuidAcceptEx), &pfAcceptEx, sizeof(pfAcceptEx), &dwBytes, NULL, NULL);
}
// start_accepting()
{
//SOCKET acceptor = create_accepting_socket();
//DWORD expected = sizeof(struct sockaddr_in) + 16;
//printf("* started accepting connections...\n");
// uses listener's completion key and overlapped structure
//sock_state.socket = acceptor;
//memset(&sock_ovl, 0, sizeof(WSAOVERLAPPED));
// starts asynchronous accept
//if (!pfAcceptEx(sock, acceptor, sock_state.buf, 0 /* no recv */, expected, expected, NULL, &sock_ovl))
//{
// int err = WSAGetLastError();
// if (err != ERROR_IO_PENDING)
// {
// printf("* error %d in AcceptEx\n", err);
// exit(1);
// }
//}
}
}
// -----------------------------------------------------------------------------
static void recvBuffer(void)
{
char* buf = msgBuf;
int pendingLen = BUFLEN;
printf("* receiving reply\n");
while (pendingLen > 0)
{
int partialLen = recv(sock, buf, pendingLen, 0);
if (partialLen > 0)
{
pendingLen -= partialLen;
buf += partialLen;
continue;
}
// ------
if (partialLen == 0)
{
printf("* connection closed by the server\n");
}
else // partialLen < 0
{
int err = WSAGetLastError();
printf("* error %d in recv\n", err);
}
exit(1);
}
}
// -----------------------------------------------------------------------------
static void run(void)
{
DWORD length;
BOOL resultOk;
WSAOVERLAPPED* ovl_res;
SocketState* socketState;
for (;;)
{
sendBuffer();
resultOk = get_completion_status(&length, &socketState, &ovl_res);
recvBuffer();
}
}
// -----------------------------------------------------------------------------
static void sendBuffer(void)
{
char* buf = msgBuf;
int pendingLen = BUFLEN;
printf("* sending message\n");
sprintf(msgBuf, "%05 *****", msgNumber++);
while (pendingLen > 0)
{
int partialLen = send(sock, buf, pendingLen, 0);
if (partialLen > 0)
{
pendingLen -= partialLen;
buf += partialLen;
continue;
}
// -----------
if (partialLen == 0)
{
printf("* connection closed by the server\n");
}
else // partialLen < 0
{
int err = WSAGetLastError();
printf("* error %d in send\n", err);
}
exit(1);
}
}
// -----------------------------------------------------------------------------
static SOCKET create_accepting_socket(void)
{
SOCKET acceptor = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (acceptor == INVALID_SOCKET)
{
printf("* error creating accept socket!\n");
exit(1);
}
return acceptor;
}
// -----------------------------------------------------------------------------
static void create_io_completion_port(void)
{
cpl_port = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
if (!cpl_port)
{
int err = WSAGetLastError();
printf("* error %d in line %d CreateIoCompletionPort\n", err, __LINE__);
exit(1);
}
}
// -----------------------------------------------------------------------------
static BOOL get_completion_status(DWORD* length, SocketState** socketState, WSAOVERLAPPED** ovl_res)
{
BOOL resultOk;
*ovl_res = NULL;
*socketState = NULL;
resultOk = GetQueuedCompletionStatus(cpl_port, length, (PULONG_PTR)socketState, ovl_res, INFINITE);
if (!resultOk)
{
DWORD err = GetLastError();
printf("* error %d getting completion port status!!!\n", err);
}
if (!*socketState || !*ovl_res)
{
printf("* don't know what to do, aborting!!!\n");
exit(1);
}
return resultOk;
}
// -----------------------------------------------------------------------------
// the end
When the server send a response by calling:
WSASend(socketState->socket, &wsabuf, 1, NULL, 0, ovl, NULL)
I’d expect it to be picked up by the client on this line:
resultOk = get_completion_status(&length, &socketState, &ovl_res);
But it doesn’t…
Would anybody be able to tell me what I’m doing wrong?
Edit:
I’ve taken the following points:
On the client side, you use WSAConnect() to create an outbound connection.
Call WSARecv() and WSASend() to start reading/writing operations when needed
you have to use WSASend/WSARecv if you want to use I/O completion ports.
and attempted to create a simple IOCP based client:
#include <iostream>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")
static DWORD WINAPI ClientWorkerThread(LPVOID lpParameter);
int main(void)
{
WSADATA WsaDat;
if (WSAStartup(MAKEWORD(2, 2), &WsaDat) != NO_ERROR)
return 0;
// Step 1 - Create an I/O completion port.
HANDLE hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
if (!hCompletionPort)
return 0;
// Step 2 - Find how many processors.
SYSTEM_INFO systemInfo;
GetSystemInfo(&systemInfo);
const int nNumberOfProcessors = systemInfo.dwNumberOfProcessors;
// Step 3 - Create worker threads.
for (int i = 0; i < nNumberOfProcessors; i++)
{
HANDLE hThread = CreateThread(NULL, 0, ClientWorkerThread, hCompletionPort, 0, NULL);
CloseHandle(hThread);
}
// Step 4 - Create a socket.
SOCKET Socket = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
if (Socket == INVALID_SOCKET)
return 0;
struct hostent *host;
if ((host = gethostbyname("localhost")) == NULL)
return 0;
SOCKADDR_IN SockAddr;
SockAddr.sin_family = AF_INET;
SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);
SockAddr.sin_port = htons(8888);
// Step 5 - Associate the socket with the I/O completion port.
CreateIoCompletionPort((HANDLE)Socket, hCompletionPort, (ULONG_PTR)0, 0);
if (WSAConnect(Socket, (SOCKADDR*)(&SockAddr), sizeof(SockAddr), NULL, NULL, NULL, NULL) == SOCKET_ERROR)
return 0;
char buffer[1000];
memset(buffer, 0, 999);
WSABUF wsaBuf = {strlen(buffer), buffer};
DWORD dwSendBytes = 0;
DWORD dwReceivedBytes = 0;
DWORD dwFlags = 0;
WSAOVERLAPPED wsaOverlapped;
SecureZeroMemory((PVOID)&wsaOverlapped, sizeof(wsaOverlapped));
wsaOverlapped.hEvent = WSACreateEvent();
for(;;)
{
WSARecv(Socket, &wsaBuf, 1, &dwReceivedBytes, &dwFlags, &wsaOverlapped, NULL);
std::cout << wsaBuf.buf;
//WSASend(Socket, &wsaBuf, 1, &dwSendBytes, 0, &wsaOverlapped, NULL);
int nError = WSAGetLastError();
if(nError != WSAEWOULDBLOCK&&nError != 0)
{
std::cout << "Winsock error code: " << nError << "\r\n";
std::cout << "Server disconnected!\r\n";
shutdown(Socket, SD_SEND);
closesocket(Socket);
break;
}
Sleep(1000);
}
WSACleanup();
system("PAUSE");
return 0;
}
static DWORD WINAPI ClientWorkerThread(LPVOID lpParameter)
{
HANDLE hCompletionPort = (HANDLE)lpParameter;
DWORD dwBytesTransferred = 0;
while (TRUE)
{
BOOL bRet = GetQueuedCompletionStatus(hCompletionPort, &dwBytesTransferred, (LPDWORD)0, (LPOVERLAPPED*)0, INFINITE);
}
return 0;
}
I know there are several things I’m doing wrong but I don’t know what they are.
Could somebody take a look at my code and give me some hints please?
Many thanks
Edit 2:
Sorry this post is getting too long.
I've had another go trying to implement an IOCP based client after reading Remy's comments below but I'm still not sure if I'm on the right track.
I'd really appreciate it if somebody could take a look at my new code (compiles fine under VS2010 & error checking omitted) below and give me some feedback.
NonBlockingClient:
#include <iostream>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
static DWORD WINAPI ClientWorkerThread(LPVOID lpParameter);
typedef struct _PER_HANDLE_DATA
{
SOCKET Socket;
} PER_HANDLE_DATA, * LPPER_HANDLE_DATA;
typedef struct
{
WSAOVERLAPPED wsaOverlapped;
WSABUF wsaBuf;
int OperationType;
} PER_IO_DATA, * LPPER_IO_DATA;
int main(void)
{
WSADATA WsaDat;
WSAStartup(MAKEWORD(2, 2), &WsaDat);
// Step 1 - Create an I/O completion port.
HANDLE hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
// Step 2 - Find how many processors.
SYSTEM_INFO systemInfo;
GetSystemInfo(&systemInfo);
// Step 3 - Create worker threads.
for (int i = 0; i < (int)systemInfo.dwNumberOfProcessors; i++)
{
HANDLE hThread = CreateThread(NULL, 0, ClientWorkerThread, hCompletionPort, 0, NULL);
CloseHandle(hThread);
}
// Step 4 - Create a socket.
SOCKET Socket = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
PER_HANDLE_DATA *pPerHandleData = new PER_HANDLE_DATA;
pPerHandleData->Socket = Socket;
struct hostent *host;
host = gethostbyname("localhost");
SOCKADDR_IN SockAddr;
SockAddr.sin_family = AF_INET;
SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);
SockAddr.sin_port = htons(8888);
// Step 5 - Associate the socket with the I/O completion port.
CreateIoCompletionPort((HANDLE)Socket, hCompletionPort, (DWORD)pPerHandleData, 0);
WSAConnect(Socket, (SOCKADDR*)(&SockAddr), sizeof(SockAddr), NULL, NULL, NULL, NULL);
static char buffer[1000];
memset(buffer, 0, 999);
PER_IO_DATA *pPerIoData = new PER_IO_DATA;
pPerIoData->wsaBuf.buf = buffer;
pPerIoData->wsaBuf.len = sizeof(buffer);
DWORD dwSendBytes = 0;
DWORD dwReceivedBytes = 0;
DWORD dwFlags = 0;
SecureZeroMemory((PVOID)&pPerIoData->wsaOverlapped, sizeof(pPerIoData->wsaOverlapped));
pPerIoData->wsaOverlapped.hEvent = WSACreateEvent();
WSARecv(Socket, &pPerIoData->wsaBuf, 1, &dwReceivedBytes, &dwFlags, &pPerIoData->wsaOverlapped, NULL);
std::cout << pPerIoData->wsaBuf.buf;
for (;;)
{
int nError = WSAGetLastError();
if (nError != WSAEWOULDBLOCK&&nError != 0)
{
std::cout << "Winsock error code: " << nError << "\r\n";
std::cout << "Server disconnected!\r\n";
shutdown(Socket, SD_SEND);
closesocket(Socket);
break;
}
Sleep(1000);
}
delete pPerHandleData;
delete pPerIoData;
WSACleanup();
return 0;
}
static DWORD WINAPI ClientWorkerThread(LPVOID lpParameter)
{
HANDLE hCompletionPort = (HANDLE)lpParameter;
DWORD bytesCopied = 0;
OVERLAPPED *overlapped = 0;
LPPER_HANDLE_DATA PerHandleData;
LPPER_IO_DATA PerIoData;
DWORD SendBytes, RecvBytes;
DWORD Flags;
BOOL bRet;
while (TRUE)
{
bRet = GetQueuedCompletionStatus(hCompletionPort, &bytesCopied, (LPDWORD)&PerHandleData, (LPOVERLAPPED*)&PerIoData, INFINITE);
if (bytesCopied == 0)
{
break;
}
else
{
Flags = 0;
ZeroMemory(&(PerIoData->wsaOverlapped), sizeof(WSAOVERLAPPED));
PerIoData->wsaBuf.len = 1000;
WSARecv(PerHandleData->Socket, &(PerIoData->wsaBuf), 1, &RecvBytes, &Flags, &(PerIoData->wsaOverlapped), NULL);
}
}
return 0;
}
NonBlockingServer:
#include <iostream>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")
int main()
{
WSADATA WsaDat;
WSAStartup(MAKEWORD(2,2), &WsaDat);
SOCKET listenSocket = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
SOCKADDR_IN server;
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
bind(listenSocket, (SOCKADDR*)(&server), sizeof(server));
listen(listenSocket, 1);
SOCKET acceptSocket = SOCKET_ERROR;
sockaddr_in saClient;
int nClientSize = sizeof(saClient);
while (acceptSocket == SOCKET_ERROR)
{
std::cout << "Waiting for incoming connections...\r\n";
acceptSocket = WSAAccept(listenSocket, (SOCKADDR*)&saClient, &nClientSize, NULL, NULL);
}
std::cout << "Client connected!\r\n\r\n";
char *szMessage = "Welcome to the server!\r\n";
WSAOVERLAPPED SendOverlapped;
DWORD SendBytes;
WSABUF DataBuf;
DataBuf.len = 1000;
DataBuf.buf = szMessage;
SecureZeroMemory((PVOID)&SendOverlapped, sizeof(WSAOVERLAPPED));
SendOverlapped.hEvent = WSACreateEvent();
for (;;)
{
WSASend(acceptSocket, &DataBuf, 1, &SendBytes, 0, &SendOverlapped, NULL);
int nError = WSAGetLastError();
if (nError != WSAEWOULDBLOCK && nError != 0)
{
std::cout << "Winsock error code: " << nError << "\r\n";
std::cout << "Client disconnected!\r\n";
shutdown(acceptSocket, SD_SEND);
closesocket(acceptSocket);
break;
}
Sleep(1000);
}
WSACleanup();
return 0;
}
Thanks again!
Try something like this:
Client:
#include <iostream>
#include <string>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
typedef struct
{
WSAOVERLAPPED Overlapped;
SOCKET Socket;
WSABUF wsaBuf;
char Buffer[1024];
DWORD Flags;
} PER_IO_DATA, * LPPER_IO_DATA;
static DWORD WINAPI ClientWorkerThread(LPVOID lpParameter)
{
HANDLE hCompletionPort = (HANDLE)lpParameter;
DWORD NumBytesRecv = 0;
ULONG CompletionKey;
LPPER_IO_DATA PerIoData;
while (GetQueuedCompletionStatus(hCompletionPort, &NumBytesRecv, &CompletionKey, (LPOVERLAPPED*)&PerIoData, INFINITE))
{
if (!PerIoData)
continue;
if (NumBytesRecv == 0)
{
std::cout << "Server disconnected!\r\n\r\n";
}
else
{
// use PerIoData->Buffer as needed...
std::cout << std::string(PerIoData->Buffer, NumBytesRecv);
PerIoData->wsaBuf.len = sizeof(PerIoData->Buffer);
PerIoData->Flags = 0;
if (WSARecv(PerIoData->Socket, &(PerIoData->wsaBuf), 1, &NumBytesRecv, &(PerIoData->Flags), &(PerIoData->Overlapped), NULL) == 0)
continue;
if (WSAGetLastError() == WSA_IO_PENDING)
continue;
}
closesocket(PerIoData->Socket);
delete PerIoData;
}
return 0;
}
int main(void)
{
WSADATA WsaDat;
if (WSAStartup(MAKEWORD(2, 2), &WsaDat) != 0)
return 0;
HANDLE hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
if (!hCompletionPort)
return 0;
SYSTEM_INFO systemInfo;
GetSystemInfo(&systemInfo);
for (DWORD i = 0; i < systemInfo.dwNumberOfProcessors; ++i)
{
HANDLE hThread = CreateThread(NULL, 0, ClientWorkerThread, hCompletionPort, 0, NULL);
CloseHandle(hThread);
}
SOCKET Socket = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
if (Socket == INVALID_SOCKET)
return 0;
SOCKADDR_IN SockAddr;
SockAddr.sin_family = AF_INET;
SockAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
SockAddr.sin_port = htons(8888);
CreateIoCompletionPort((HANDLE)Socket, hCompletionPort, 0, 0);
if (WSAConnect(Socket, (SOCKADDR*)(&SockAddr), sizeof(SockAddr), NULL, NULL, NULL, NULL) == SOCKET_ERROR)
return 0;
PER_IO_DATA *pPerIoData = new PER_IO_DATA;
ZeroMemory(pPerIoData, sizeof(PER_IO_DATA));
pPerIoData->Socket = Socket;
pPerIoData->Overlapped.hEvent = WSACreateEvent();
pPerIoData->wsaBuf.buf = pPerIoData->Buffer;
pPerIoData->wsaBuf.len = sizeof(pPerIoData->Buffer);
DWORD dwNumRecv;
if (WSARecv(Socket, &(pPerIoData->wsaBuf), 1, &dwNumRecv, &(pPerIoData->Flags), &(pPerIoData->Overlapped), NULL) == SOCKET_ERROR)
{
if (WSAGetLastError() != WSA_IO_PENDING)
{
delete pPerIoData;
return 0;
}
}
while (TRUE)
Sleep(1000);
shutdown(Socket, SD_BOTH);
closesocket(Socket);
WSACleanup();
return 0;
}
Server:
#include <iostream>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")
typedef struct
{
WSAOVERLAPPED Overlapped;
SOCKET Socket;
WSABUF wsaBuf;
char Buffer[1024];
DWORD BytesSent;
DWORD BytesToSend;
} PER_IO_DATA, * LPPER_IO_DATA;
static DWORD WINAPI ServerWorkerThread(LPVOID lpParameter)
{
HANDLE hCompletionPort = (HANDLE)lpParameter;
DWORD NumBytesSent = 0;
ULONG CompletionKey;
LPPER_IO_DATA PerIoData;
while (GetQueuedCompletionStatus(hCompletionPort, &NumBytesSent, &CompletionKey, (LPOVERLAPPED*)&PerIoData, INFINITE))
{
if (!PerIoData)
continue;
if (NumBytesSent == 0)
{
std::cout << "Client disconnected!\r\n\r\n";
}
else
{
PerIoData->BytesSent += NumBytesSent;
if (PerIoData->BytesSent < PerIoData->BytesToSend)
{
PerIoData->wsaBuf.buf = &(PerIoData->Buffer[PerIoData->BytesSent]);
PerIoData->wsaBuf.len = (PerIoData->BytesToSend - PerIoData->BytesSent);
}
else
{
PerIoData->wsaBuf.buf = PerIoData->Buffer;
PerIoData->wsaBuf.len = strlen(PerIoData->Buffer);
PerIoData->BytesSent = 0;
PerIoData->BytesToSend = PerIoData->wsaBuf.len;
}
if (WSASend(PerIoData->Socket, &(PerIoData->wsaBuf), 1, &NumBytesSent, 0, &(PerIoData->Overlapped), NULL) == 0)
continue;
if (WSAGetLastError() == WSA_IO_PENDING)
continue;
}
closesocket(PerIoData->Socket);
delete PerIoData;
}
return 0;
}
int main()
{
WSADATA WsaDat;
if (WSAStartup(MAKEWORD(2,2), &WsaDat) != 0)
return 0;
HANDLE hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
if (!hCompletionPort)
return 0;
SYSTEM_INFO systemInfo;
GetSystemInfo(&systemInfo);
for (DWORD i = 0; i < systemInfo.dwNumberOfProcessors; ++i)
{
HANDLE hThread = CreateThread(NULL, 0, ServerWorkerThread, hCompletionPort, 0, NULL);
CloseHandle(hThread);
}
SOCKET listenSocket = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
if (listenSocket == INVALID_SOCKET)
return 0;
SOCKADDR_IN server;
ZeroMemory(&server, sizeof(server));
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
if (bind(listenSocket, (SOCKADDR*)(&server), sizeof(server)) != 0)
return 0;
if (listen(listenSocket, 1) != 0)
return 0;
std::cout << "Waiting for incoming connection...\r\n";
SOCKET acceptSocket;
do
{
sockaddr_in saClient;
int nClientSize = sizeof(saClient);
acceptSocket = WSAAccept(listenSocket, (SOCKADDR*)&saClient, &nClientSize, NULL, NULL);
}
while (acceptSocket == INVALID_SOCKET);
std::cout << "Client connected!\r\n\r\n";
CreateIoCompletionPort((HANDLE)acceptSocket, hCompletionPort, 0, 0);
LPPER_IO_DATA pPerIoData = new PER_IO_DATA;
ZeroMemory(pPerIoData, sizeof(PER_IO_DATA));
strcpy(pPerIoData->Buffer, "Welcome to the server!\r\n");
pPerIoData->Overlapped.hEvent = WSACreateEvent();
pPerIoData->Socket = acceptSocket;
pPerIoData->wsaBuf.buf = pPerIoData->Buffer;
pPerIoData->wsaBuf.len = strlen(pPerIoData->Buffer);
pPerIoData->BytesToSend = pPerIoData->wsaBuf.len;
DWORD dwNumSent;
if (WSASend(acceptSocket, &(pPerIoData->wsaBuf), 1, &dwNumSent, 0, &(pPerIoData->Overlapped), NULL) == SOCKET_ERROR)
{
if (WSAGetLastError() != WSA_IO_PENDING)
{
delete pPerIoData;
return 0;
}
}
while (TRUE)
Sleep(1000);
shutdown(acceptSocket, SD_BOTH);
closesocket(acceptSocket);
WSACleanup();
return 0;
}
Have you had a look at the example in the MSDN documentation for WSARecv?
Essentially, you have to start the asynchronous WSARecv operation first and then get notified via the completion port of its completion.
Or to put it another way: Windows I/O completion ports are using a proactor model (in contrast to the reactor model of Linux/FreeBSD/NetBSD).