EDIT: I am guessing the problem is I have to associate the OVERLAPPED or WSAOVERLAPPED in the container with my completion port. Is that correct?
I can get IO completions when someone connects to my server. I then use CreateIoCompletionPort on the new socket, with the completionport that original was used. But when they send me data, it does not get set off. Although, it still gets set off if someone else connects. My question is, why would this happen? I also make sure CreateIoCompletionPort returns the same handle as was the original. What gives?
EDIT:
DWORD WINAPI worker_thread(LPVOID lpParam) {
client_information_class *cicc = NULL;
HANDLE CompletionPort = (HANDLE)lpParam;
ULONG_PTR Key;
DWORD BytesTransfered;
OVERLAPPED *lpOverlapped = NULL;
DWORD error = NULL;
while(1) {
error = GetQueuedCompletionStatus(CompletionPort, &BytesTransfered, (PULONG_PTR)&Key, &lpOverlapped, 0);
cicc = CONTAINING_RECORD ( lpOverlapped, client_information_class, ol );
if ( error == TRUE ) {
cout << endl << "IO TRIGGERED" << endl;
switch ( cicc->operation ) {
/*#define OP_ACCEPT 0
#define OP_READ 1
#define OP_WRITE 2*/
case 0:{
if ( check_auth_progress ( cicc->client_socket , cicc->client_buff , BytesTransfered ) ) {
cout << "Client " << cicc->client_socket << " connected." << endl;
client_information_class *k = NULL;
SOCKADDR_STORAGE *LocalSockaddr=NULL, *RemoteSockaddr=NULL;
int LocalSockaddrLen,RemoteSockaddrLen;
k = (client_information_class *)Key;
k->lpfnGetAcceptExSockaddrs(
cicc->client_buff,
cicc->client_len - ((sizeof(SOCKADDR_STORAGE) + 16) * 2),
sizeof(SOCKADDR_STORAGE) + 16,
sizeof(SOCKADDR_STORAGE) + 16,
(SOCKADDR **)&cicc->LocalSockaddr,
&cicc->LocalSockaddrLen,
(SOCKADDR **)&cicc->RemoteSockaddr,
&cicc->RemoteSockaddrLen
);
client_information_class *cicc2 = NULL;
cicc2 = ( client_information_class *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(client_information_class) + (sizeof(BYTE) * 4096));
if (cicc2 == NULL) {
fprintf(stderr, "Out of memory!\n");
}
cicc2->client_socket = cicc->client_socket;
cicc2->client_socketaddr_in = cicc->client_socketaddr_in;
cicc2->LocalSockaddr = cicc->LocalSockaddr;
cicc2->LocalSockaddrLen = cicc->LocalSockaddrLen;
cicc2->RemoteSockaddr = cicc->RemoteSockaddr;
cicc2->RemoteSockaddrLen = cicc->RemoteSockaddrLen;
HANDLE hrc = CreateIoCompletionPort( (HANDLE)cicc2->client_socket, CompletionPort, (ULONG_PTR)cic, 0 );
if (hrc == NULL) {
fprintf(stderr, "CompletionThread: CreateIoCompletionPort failed: %d\n", GetLastError());
return 0;
} else {
fprintf(stderr, "CompletionThread: CreateIoCompletionPort: %d\n", hrc);
}
cic->deleteNode ( cicc->client_socket , cic );
cic->addNode ( cicc2 );
} else {
cout << endl << "Something Happened ... " << endl;
}
}break;
case 1:{
if ( ParsePacket ( cicc->client_socket , data ) ) {
cout << "Client " << cicc->client_socket << " connected." << endl;
} else {
cout << endl << "Something Happened ... " << endl;
}
}break;
default:{
cout << endl << "Didnt catch that operation ... " << cicc->operation << endl;
}break;
}
} else if ( error == FALSE && &lpOverlapped == NULL ) {
// no packet was dequed...
fprintf(stderr, "[error == FALSE && &lpOverlapped == NULL] CompletionThread: GetQueuedCompletionStatus failed: %d [0x%x]\n", GetLastError(), &lpOverlapped->Internal);
} else if ( error == FALSE && &lpOverlapped != NULL ) {
if((DWORD)&lpOverlapped->Internal == 0x0) { // a timeout...
} else {
fprintf(stderr, "[error == FALSE && &lpOverlapped != NULL] CompletionThread: GetQueuedCompletionStatus failed: %d [0x%x]\n", GetLastError(), &lpOverlapped->Internal);
}
}
}
ExitThread(0);
return 0;
}
Id hate to do this again, but I was correct, you have to place the socket into a new mode (much like acceptex) using WSARECV: I did not know this, and its not very clear on the MSDN, and one of the sources I was looking at to learn IOCP, doesn't talk about it. Hopefully this helps someone :/
WSABUF wbuf;
DWORD bytes, flags;
wbuf.buf = cicc2->client_buff;
wbuf.len = cicc2->client_len;
flags = 0;
int rr = WSARecv ( cicc2->client_socket , &wbuf , 1 , &bytes , &flags , &cicc2->ol , NULL );
if (rr == FALSE) {
if (WSAGetLastError() != WSA_IO_PENDING) {
printf("PostRecv: WSARecv* failed: %d\n", WSAGetLastError());
closesocket(cicc2->client_socket);
cic->deleteNode ( cicc2->client_socket , cic );
}
fprintf(stderr, "PostRecv: WSARecv* failed: %d\n", GetLastError());
}
Related
I am using windows sockets with c++. In the following call I am trying to reply a message to the socket that just connected.
I tried connecting using a dummy client in c++. It would connect but the recv() would not receive anything.
Then I tried using telnet, it worked instantly, just as i wanted.
SOCKET s = accept(ls, (sockaddr*)&clientSin, &s_len);
if (s == INVALID_SOCKET) {
cerr << "Error in accept call: " << WSAGetLastError();
}
else {
cout << "Connection accepted at , socket no. :" << s << endl;
//adding to list of incoming sockets
inactiveList.push_back(s);
//send message to client requesting credentials
char buff[10];
// the character 'x' is a code to the client to provide the server with the credentials
buff[0] = 'x';
buff[1] = '\0';
//send(s, buff, 2, 0);
if (send(s, "From Vic: ", 10, 0) == INVALID_SOCKET)
{
int errorcode = WSAGetLastError();
cerr << "send to client failed: " << errorcode << endl;
closesocket(s);
continue;
}
Sleep(1000);
if (send(s, "From Vic: ", 10, 0) == INVALID_SOCKET)
{
int errorcode = WSAGetLastError();
cerr << "send to client failed: " << errorcode << endl;
closesocket(s);
continue;
}
}
the recv code is:
tnb = 0;
while ((nb = recv(s, &buff[tnb], LINESZ - tnb, 0)) > 0)
{
tnb += nb;
}
/* If there was an error on the read, report it. */
if (nb < 0)
{
printf("recv failed: %d\n", WSAGetLastError());
return 1;
}
if (tnb == 0)
{
printf("Disconnect on recv");
}
/* Make the response NULL terminated and display it. Using C output */
printf("tnb = %d\n", tnb);
buff[tnb] = '\0';
puts(buff);
Taking all my comments and turning it into an answer.
I suspect your recv loop is continuing forever because you haven't sent enough data to make it break out of the loop.
Change this:
while ((nb = recv(s, &buff[tnb], LINESZ - tnb, 0)) > 0)
{
tnb += nb;
}
To this: (notice that I'm allocating +1 for the array buff)
char buff[LINESZ+1]; // +1 for null terminator
buff[0] = '\0';
tnb = 0;
while (tnb < LINESZ)
{
nb = recv(s, &buff[tnb], LINESZ-tnb, 0);
if (nb < 0)
{
printf("Error on socket: %d\n", (int)WSAGetLastError());
break;
}
else if (nb == 0)
{
printf("Remote socket closed\n");
break;
}
printf("Received: %d bytes\n", (int)nb);
tnb += nb;
buff[tnb] = '\0'; // null terminate the end of the buffer so it will print reliably
}
I have this function which if you connect to a system with ssh, you can call it to execute your given command on that system.
std::string sshconnection::exec_ssh_command(ssh_session session, char *command) {
string receive = "";
int rc, nbytes;
char buffer[256];
ssh_channel channel = ssh_channel_new(session);
if( channel == NULL )
return NULL;
rc = ssh_channel_open_session(channel);
if( rc != SSH_OK ) {
ssh_channel_free(channel);
return NULL;
}
rc = ssh_channel_request_exec(channel, command);
if( rc != SSH_OK ) {
ssh_channel_close(channel);
ssh_channel_free(channel);
cout << "Error";
return NULL;
}
nbytes = ssh_channel_read(channel, buffer, sizeof(buffer), 0);
while (nbytes > 0)
{
if (write(1, buffer, nbytes) != (unsigned int) nbytes)
{
ssh_channel_close(channel);
ssh_channel_free(channel);
return NULL;
}
nbytes = ssh_channel_read(channel, buffer, sizeof(buffer), 0);
}
if( nbytes < 0 )
return NULL;
ssh_channel_send_eof(channel);
ssh_channel_close(channel);
ssh_channel_free(channel);
return receive;
}
this function works great. I just don't understand that part which is about to write from buffer into a file descriptor=1 . we haven't filled receive anywhere but it is the return value. if we call this function like below:
s = exec_ssh_command(my_ssh_session, "cat /proc/stat" );
the s won't have any value, but if we do this:
std::cout<<s;
this will print s value. and of course we can't save s in a file. can someone explain to me how is this happening?
EDIT:function to connect to ssh:
int sshconnection::sshConnection()
{
if( my_ssh_session == NULL ) {
cout << "Error creating ssh session" << endl;
return 1;
}
ssh_options_set(my_ssh_session, SSH_OPTIONS_HOST, "yourip");
ssh_options_set(my_ssh_session, SSH_OPTIONS_USER, "username");
int rc = ssh_connect(my_ssh_session);
if( rc != SSH_OK ) {
cout << "Error with connecting" << endl;
ssh_free(my_ssh_session);
return -1;
}
rc = ssh_userauth_password(my_ssh_session, NULL, "yourpassword");
if( rc != SSH_AUTH_SUCCESS) {
cout << "Error with authorization " << ssh_get_error(my_ssh_session) << endl;
ssh_disconnect(my_ssh_session);
ssh_free(my_ssh_session);
return -1;
}
// ssh_disconnect(my_ssh_session);
// ssh_free(my_ssh_session);
}
I know this is old, but I had the same issue. I came up with the following solution.
Use std::string::append like so receive.append(buffer, nbytes).
std::string sshconnection::exec_ssh_command(ssh_session session, char *command) {
string receive = "";
int rc, nbytes;
char buffer[256];
ssh_channel channel = ssh_channel_new(session);
if( channel == NULL )
return NULL;
rc = ssh_channel_open_session(channel);
if( rc != SSH_OK ) {
ssh_channel_free(channel);
return NULL;
}
rc = ssh_channel_request_exec(channel, command);
if( rc != SSH_OK ) {
ssh_channel_close(channel);
ssh_channel_free(channel);
cout << "Error";
return NULL;
}
nbytes = ssh_channel_read(channel, buffer, sizeof(buffer), 0);
while (nbytes > 0)
{
receive.append(buffer, nbytes);
nbytes = ssh_channel_read(channel, buffer, sizeof(buffer), 0);
}
if( nbytes < 0 )
return NULL;
ssh_channel_send_eof(channel);
ssh_channel_close(channel);
ssh_channel_free(channel);
return receive;
}
All :)
I have some piece of code with correctly works on Linux and WinXP
int FlowTestIP::do_recvfrom()
{
int ret;
struct timeval timeout;// = {2, 0};
timeout.tv_sec = 2;
timeout.tv_usec = 0;
fd_set rfds;
while(running) {
FD_ZERO(&rfds);
FD_SET(m_socket, &rfds);
ret = select(m_socket + 1, &rfds, 0, 0, &timeout);
cout << "// select ret = " << ret << " (errno = " << errno << ")" << endl;
if (ret == -1 || ret == 0) {
if (!(ret == 0 && errno == 0))
cout << "select ret = " << ret << " (errno = " << errno << ")" << endl;
return ret;
}
if (FD_ISSET(m_socket, &rfds)) {
cout << WSAGetLastError() << endl;
break;
}
}
return recvfrom(m_socket, in_buf, mtu, 0, (struct sockaddr *)&si_other, (socklen_t *)&otherAddrSize);
}
But in Windows 7 in continues to loop even when client apptication is exited.
Bad output is
...
// select ret = 1 (errno = 0)
0
// select ret = 1 (errno = 0)
0
// select ret = 1 (errno = 0)
0
FTControlServerThread::run
FTControlServerThread::recieved
pkt->ft_tos = UCHAR_MAX
QFuture::waitForFinished()
client alive true
// select ret = 1 (errno = 0)
0
// select ret = 1 (errno = 0)
0
// select ret = 1 (errno = 0)
0
normaly (on WinXP and Linux) output will be
...
// select ret = 1 (errno = 0)
0
// select ret = 1 (errno = 0)
0
// select ret = 1 (errno = 0)
0
FTControlServerThread::run
FTControlServerThread::recieved
pkt->ft_tos = UCHAR_MAX
QFuture::waitForFinished()
client alive true
QFuture::finished
And that is what I am waiting from it.
Has anyone encountered with such a misbehaviour?
Thanks in advance!
P.S. As #JoachimPileborg asked to show how I call this function:
FlowTest::recv(char *payload, size_t size)
{
...
while (running) {
len = do_recvfrom(); // it virtual method of class FlowTest
if (len == -1 || len == 0) {
return len;
}
if (running && !transport_recv_helper()) {
continue;
} else {
break;
}
}
...
}
and recv is called from server GUI
void FlowTestServer::runTest(FlowTestServerHelper handler)
{
...
if ((ret = server->recv(rcvdData, (size_t *)&size)) == -1 || ret == 0 || size == 0) {
if (server_busy == 0)
break;
cout << "can't receive data (size == " << size << "; ret = " << ret << ")" << endl;
continue;
}
...
}
Firstly: Using cout is allowed to reset errno. It doesn't usually, but it can, especially on first use when it has to set up the locale. You need to save the value of errno in a temp variable, or use fprintf and friends - as a C lib function POSIX controls its behavior.
Secondly: In Windows, you need to use WSAGetLastError() not errno.
I suggest you make a macro sock_errno which will be (errno) on Linux/unix, and (WSAGetLastError()) on Windows. That will enable to you to code in a platform independent manner.
See here for more: http://msdn.microsoft.com/en-us/library/windows/desktop/ms737828(v=vs.85).aspx
I have a C++ program where I connect to my server with a socket and I need to set the overlapped for the socket. Doing the following does not work:
Function
int set_wsa_proxy_client ( proxy_client *node ) {
WSABUF wbuf;
DWORD bytes, flags;
int BufLen = 1024;
wbuf.buf = node->buf;
wbuf.len = node->len;
flags = 0;
int rr = WSARecv ( node->s , &wbuf , 1 , &bytes , &flags , &node->ov , NULL );
if (rr == FALSE) {
if (WSAGetLastError() != WSA_IO_PENDING) {
printf("PostRecv: WSARecv* failed: %d\n", WSAGetLastError());
if ( WSAGetLastError() == ERROR_SUCCESS ) { // this means it completed right away ...
//cout << endl << "ERROR_SUCCESS - set_wsa_lobby_client completed" << endl;
//cout << endl << "BYTES: " << node->len << endl;
return 0;
}
return WSAGetLastError();
}
}
return 0;
}
Extension
typedef struct OverlappedEx : OVERLAPPED {
int id;
} OverlappedEx;
proxy_client struct
struct proxy_client {
// ... blah blah blah
SOCKET s;
OverlappedEx ov;
// ... blah blah blah
}
Main
HANDLE ServerCompletionPort = CreateIoCompletionPort ( INVALID_HANDLE_VALUE , NULL , (ULONG_PTR)NULL , 0 );
if ( ServerCompletionPort == NULL ) { fprintf( stderr , "CreateIoCompletionPort failed: %d\n" , GetLastError() ); return -1; }
proxy_client *new_c = new proxy_client;
memset(&new_c->ov , 0 , sizeof(new_c->ov));
new_c->ov.hEvent = ServerCompletionPort;
new_c->s = (make socket)
// ... Connect and other stuff ...
HANDLE hrc = CreateIoCompletionPort( (HANDLE)new_c->s, new_c->ov.hEvent, (ULONG_PTR)pc, 0 ); // pc is the global struct of proxy_client
if (hrc == NULL)
fprintf(stderr, "CompletionThread: CreateIoCompletionPort failed: %d\n", GetLastError());
int r = 0;
if ( ( r = set_wsa_proxy_client ( new_c ) ) != 0 ) {
//
} else {
//
}
This does not seem to trigger the socket when I GetQueuedCompletionStatus for ServerCompletionPort, after sending the socket data (from the server). I was wondering how I can set an IO for a socket! Thank for the help! :-)
I have written a class to handle named pipe connections, and if I create an instance, close it, and then try to create another instance the call to CreateFile() returns INVALID_HANDLE_VALUE, and GetLastError() returns ERROR_PIPE_BUSY. What's going on here? What can I do to insure the call to Connect() succeeds?
PipeAsync A, B;
A.Connect("\\\\.\\pipe\\test",5000);
A.Close();
cout << GetLastError(); // some random value
B.Connect("\\\\.\\pipe\\test",5000);
cout << GetLastError(); // 231 (ERROR_PIPE_BUSY)
B.Close();
Here are my implementations of Connect() and Close()
BOOL PipeAsync::Connect(LPCSTR pszPipeName, DWORD dwTimeout)
{
this->pszPipeName = pszPipeName;
this->fExisting = TRUE;
DWORD dwMode = this->fMessageMode ? PIPE_READMODE_MESSAGE : PIPE_READMODE_BYTE;
hPipe = CreateFile(
this->pszPipeName,
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,
NULL);
if( INVALID_HANDLE_VALUE == hPipe )
return FALSE; /* set break point here ; breaks here on second call to Connect() */
if( GetLastError() == ERROR_PIPE_BUSY )
if(!WaitNamedPipe( this->pszPipeName, dwTimeout ))
return FALSE; /* set break point here */
if( !SetNamedPipeHandleState( hPipe, &dwMode, NULL, NULL ) )
return FALSE; /* set break point here */
return TRUE;
}
VOID PipeAsync::Close()
{
if( fExisting )
DisconnectNamedPipe( hPipe );
CloseHandle( hPipe );
}
EDIT: I forgot to tell you how I concluded this... I set break points indicated in the comments. When run, it stops on the first break point.
EDIT: This is my updated code
if( INVALID_HANDLE_VALUE == hPipe )
if( GetLastError() == ERROR_PIPE_BUSY )
{
if(!WaitNamedPipe( this->pszPipeName, dwTimeout ))
return FALSE; /* break-point: breaks here on second call */
}
else
return FALSE; /* break-point /*
Now, WaitNamedPipe() is returning false on the second call to Connect() and GetLastError() is returning 2, or ERROR_FILE_NOT_FOUND ?
From Named Pipe Client:
If the pipe exists but all of its instances are busy, CreateFile
returns INVALID_HANDLE_VALUE and the GetLastError function returns
ERROR_PIPE_BUSY. When this happens, the named pipe client uses the
WaitNamedPipe function to wait for an instance of the named pipe to
become available.
The link has example code on coping with ERROR_PIPE_BUSY.
EDIT:
Small compilable example that demonstrates accepting and connecting on a named pipe:
const char* const PIPE_NAME = "\\\\.\\pipe\\test";
const int MAX_CONNECTIONS = 10;
void client_main()
{
DWORD last_error;
unsigned int elapsed_seconds = 0;
const unsigned int timeout_seconds = 5;
HANDLE handle = CreateFile(PIPE_NAME,
GENERIC_READ | GENERIC_WRITE,
0,
0,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
0);
while (INVALID_HANDLE_VALUE == handle &&
elapsed_seconds < timeout_seconds)
{
last_error = GetLastError();
if (last_error != ERROR_PIPE_BUSY)
{
break;
}
Sleep(1 * 1000);
elapsed_seconds++;
handle = CreateFile(PIPE_NAME,
GENERIC_READ | GENERIC_WRITE,
0,
0,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
0);
}
if (INVALID_HANDLE_VALUE == handle)
{
std::cerr << "Failed to connect to pipe " << PIPE_NAME <<
": last_error=" << last_error << "\n";
}
else
{
std::cout << "Connected to pipe " << PIPE_NAME << "\n";
CloseHandle(handle);
}
}
HANDLE _get_server_handle()
{
// Error handling omitted for security descriptor creation.
SECURITY_DESCRIPTOR sd;
InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION);
SetSecurityDescriptorDacl(&sd, TRUE, static_cast<PACL>(0), FALSE);
SECURITY_ATTRIBUTES sa;
sa.nLength = sizeof(sa);
sa.lpSecurityDescriptor = &sd;
sa.bInheritHandle = FALSE;
// Create a bi-directional message pipe.
HANDLE handle = CreateNamedPipe(PIPE_NAME,
PIPE_ACCESS_DUPLEX,
PIPE_TYPE_MESSAGE |
PIPE_READMODE_MESSAGE |
PIPE_NOWAIT,
PIPE_UNLIMITED_INSTANCES,
4096,
4096,
0,
&sa);
if (INVALID_HANDLE_VALUE == handle)
{
std::cerr << "Failed to create named pipe handle: last_error=" <<
GetLastError() << "\n";
}
return handle;
}
void server_main()
{
HANDLE handle = _get_server_handle();
if (INVALID_HANDLE_VALUE != handle)
{
int count = 0;
while (count < MAX_CONNECTIONS)
{
BOOL result = ConnectNamedPipe(handle, 0);
const DWORD last_error = GetLastError();
if (ERROR_NO_DATA == last_error)
{
count++;
std::cout << "A client connected and disconnected: count=" <<
count << "\n";
CloseHandle(handle);
handle = _get_server_handle();
}
else if (ERROR_PIPE_CONNECTED == last_error)
{
count++;
std::cout << "A client connected before call to " <<
"ConnectNamedPipe(): count=" << count << "\n";
CloseHandle(handle);
handle = _get_server_handle();
}
else if (ERROR_PIPE_LISTENING != last_error)
{
std::cerr << "Failed to wait for connection: last_error=" <<
GetLastError() << "\n";
CloseHandle(handle);
break;
}
Sleep(100);
}
}
}
int main(int a_argc, char** a_argv)
{
if (2 == a_argc)
{
if (std::string("client") == *(a_argv + 1))
{
for (int i = 0; i < MAX_CONNECTIONS; i++)
{
client_main();
}
}
else if (std::string("server") == *(a_argv + 1))
{
server_main();
}
}
return 0;
}
Execute server-side first:
pipetest.exe server
Then execute client-side:
pipetest.exe client
I could not tell what the problem was from the posted code. Hopefully this small example will assist you in finding the issue.