I have a server socket accepting client socket connections. Accept is in a thread
socket creation
int ServerSocket::CreateSocket(int port)
{
listenfd = 0;
struct sockaddr_in serv_addr;
unsigned long iMode = 1;
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&serv_addr, '0', sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(port);
ioctlsocket(listenfd, FIONBIO, &iMode);
if (bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
{
return 0;
}
if (listen(listenfd, 20) < 0)
{
return 0;
}
return listenfd;
}
Socket Accept
void ServerSocket::AcceptClients_1(void * p)
{
struct sockaddr_in cli_addr;
// get a pointer to the ServerSocket object
ServerSocket * pThis = (ServerSocket *)p;
int iResult, cli_len;
cli_len = sizeof(cli_addr);
struct timeval tv = { 0, 1000 };
SOCKET s = pThis->GetSocket();
fd_set rfds;
FD_ZERO(&rfds);
FD_SET(s, &rfds);
while (!pThis->ShutDownRequested)
{
iResult = select(s+1, &rfds, (fd_set *) 0, (fd_set *) 0, &tv);
if(iResult > 0)
{
// never comes here
SOCKET sclient = accept(s, (struct sockaddr *)&cli_addr,
&cli_len);
}
else if (iResult == 0) /// timeout
{
continue;
}
// error comes here are going to accept 2nd time
DWORD dwError = GetLastError();
return;
}
}
The code comes on select(). Returns 0 the first time but second time always returns -1 with error 10022. I don't understand why. Please help.
Make sure your pThis->GetSocket() is correctly returning the listenfd. Also, you should reinitialize cli_len = sizeof(cli_addr); before each call to accept (it's a value-result argument).
iResult=0 does not always mean timeout, for non-blocking sockets, you need to check WSAGetLastError and deal with some error codes, for example WSAEWOULDBLOCK means you need to wait next event on this socket.
http://msdn.microsoft.com/en-us/library/windows/desktop/ms740668(v=vs.85).aspx
Related
I'am trying to set my own timeot for connect() function.
my code works well with default connection like this:
bool connectFUNC4(char * ipaddr) {
WSADATA wsa;
struct sockaddr_in server;
if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
return false;
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
return false;
server.sin_addr.s_addr = inet_addr(ipaddr);
server.sin_family = AF_INET;
server.sin_port = htons(5577);
if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0)
return false;
return true;
}
I understand idea with blocking and not blocking connection, and I've found solution with setting to nonblocking mode and timeout. It always finished successful but communication does not work.
bool connectFUNC3(char * ipaddr) {
WSADATA wsa;
struct sockaddr_in server;
server.sin_addr.s_addr = inet_addr(ipaddr);
server.sin_family = AF_INET;
server.sin_port = htons(5577);
unsigned long block = 1;
ioctlsocket((unsigned int)sock, FIONBIO, &block);
WSAGetLastError();
int ret = connect(sock, (struct sockaddr *)&server, sizeof(server));
timeval time_out;
time_out.tv_sec = 5;
time_out.tv_usec = 0;
fd_set setW, setE;
FD_ZERO(&setW);
FD_SET(sock, &setW);
FD_ZERO(&setE);
FD_SET(sock, &setE);
select(0, NULL, &setW, &setE, &time_out);
bool flag;
if (FD_ISSET(sock, &setW))
{
// connection successful
flag = true;
}
else if (FD_ISSET(sock, &setE))
{
// connection fail
flag = false;
}
else
{
// connection timeout
flag = false;
}
block = 0;
ioctlsocket((unsigned int)sock, FIONBIO, &block);
return flag;
}
Please help to make it work, or to find another solution (multithread not usable in my case). Thank you.
Neither of your functions are checking ANY return values for errors. And when calling select() in non-blocking mode, call it only if connect() fails with a WSAEWOULBLOCK error, and if select() then returns > 0 then you should be checking setE first and not setW.
Try something more like this:
void closesock(SOCKET *s)
{
// preserve current error code
int err = WSAGetLastError();
closesocket(*sock);
*sock = INVALID_SOCKET;
WSASetLastError(err);
}
bool connectFUNC4(char * ipaddr)
{
// you really shouldn't be calling WSAStartup() here.
// Call it at app startup instead...
struct sockaddr_in server = {0};
server.sin_family = AF_INET;
server.sin_addr.s_addr = inet_addr(ipaddr);
server.sin_port = htons(5577);
// ipaddr valid?
if (server.sin_addr.s_addr == INADDR_NONE)
return false;
sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock == INVALID_SOCKET)
return false;
if (connect(sock, (struct sockaddr *)&server, sizeof(server)) == SOCKET_ERROR)
{
// connection failed
closesock(&sock);
return false;
}
// connection successful
return true;
}
bool connectFUNC3(char * ipaddr)
{
// you really shouldn't be calling WSAStartup() here.
// Call it at app startup instead...
struct sockaddr_in server = {0};
server.sin_family = AF_INET;
server.sin_addr.s_addr = inet_addr(ipaddr);
server.sin_port = htons(5577);
// ipaddr valid?
if (server.sin_addr.s_addr == INADDR_NONE)
return false;
sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock == INVALID_SOCKET)
return false;
// put socked in non-blocking mode...
u_long block = 1;
if (ioctlsocket(sock, FIONBIO, &block) == SOCKET_ERROR)
{
closesock(&sock);
return false;
}
if (connect(sock, (struct sockaddr *)&server, sizeof(server)) == SOCKET_ERROR)
{
if (WSAGetLastError() != WSAEWOULDBLOCK)
{
// connection failed
closesock(&sock);
return false;
}
// connection pending
fd_set setW, setE;
FD_ZERO(&setW);
FD_SET(sock, &setW);
FD_ZERO(&setE);
FD_SET(sock, &setE);
timeval time_out = {0};
time_out.tv_sec = 5;
time_out.tv_usec = 0;
int ret = select(0, NULL, &setW, &setE, &time_out);
if (ret <= 0)
{
// select() failed or connection timed out
closesock(&sock);
if (ret == 0)
WSASetLastError(WSAETIMEDOUT);
return false;
}
if (FD_ISSET(sock, &setE))
{
// connection failed
int err = 0;
getsockopt(sock, SOL_SOCKET, SO_ERROR, &err, sizeof(err));
closesock(&sock);
WSASetLastError(err);
return false;
}
}
// connection successful
// put socked in blocking mode...
block = 0;
if (ioctlsocket(sock, FIONBIO, &block) == SOCKET_ERROR)
{
closesock(&sock);
return false;
}
return true;
}
I have two programs, on is server and only listening and the client is talking. I send 1mbytes of data in chunks of 64bytes each. I will get the first chunk of 64byte but then my server exits because it failed to get other data. My client is sending all of the data.
void ServerLinux::Receive(){
int sock = 0;
struct sockaddr_in server;
char buffer[this->packageLength];
if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
this->Die("Failed to create socket");
}
memset(&server, 0, sizeof(server));
server.sin_family = AF_INET;
server.sin_addr.s_addr = htonl(INADDR_ANY);
server.sin_port = htons(this->port);
if(bind(sock, (struct sockaddr *) &server, sizeof(server)) < 0){
this->Die("Failed to bind the server socket");
}
if(listen(sock, 1) < 0){
this->Die("Failed to listen on server socket");
}
int clientSocket = 0;
struct sockaddr_in client;
socklen_t size = sizeof(client);
if((clientSocket = accept(sock, (struct sockaddr *) &client, &size)) < 0){
this->Die("Failed to accept client");
}
int received = -1;
//This is fine data is recived
if((received = recv(clientSocket, buffer, this->packageLength,0)) < 0){
this->Die("Failed to receive initial bytes from client");
}
std::cout << "Received!" << std::endl;
//Data is not received in this while loop
while(received > 0){
if((received = recv(sock, buffer, this->packageLength,0)) < 0){
this->Die("Failed to receive additional bytes frin client");
}
std::cout << "Received!" << std::endl;
}
}
Why don't you use the same arguments for recv?
works: recv(clientSocket, buffer, this->packageLength,0)
doesn't work recv(sock, buffer, this->packageLength,0)
Change sock to clientSocket.
I want to receive UDP packets from a server application (on the same computer) and forward it to an UDP receive app on a different port.
The server app is not mine, nor do i have the source code.
The UDP receive app is a Java application.
If i bind the Java application directly to the server app port, there is very low latency, but if i connect it to the relay app´port i get almost one second of delay.
The receiving port has to be non-blocking.
#define rcv_length 160
fd_set fds;
int n;
struct timeval tv;
void CMClient::startUDPListener(){
CMport_number = 32200;
remoteAddrLen = sizeof(struct sockaddr_in);
if (WSAStartup(0x0101, &CMw) != 0)
{
fprintf(stderr, "Could not open Windows connection.\n");
exit(0);
}
CMsd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (CMsd == INVALID_SOCKET)
{
fprintf(stderr, "Could not create socket.\n");
WSACleanup();
exit(0);
}
CMserver.sin_family = AF_INET;
CMserver.sin_port = htons(CMport_number);
CMserver.sin_addr.s_addr = inet_addr("127.0.0.1");
long rc=bind(CMsd,(SOCKADDR*)&CMserver,sizeof(SOCKADDR_IN));
if(rc==SOCKET_ERROR)
{
printf("Error: bind code: %d\n",WSAGetLastError());
}
}
void CMClient::updateData(UDPServer* svr, int CMnr){
FD_ZERO(&fds);
FD_SET(CMsd, &fds);
tv.tv_sec = 0;
tv.tv_usec = 1;
n = select ( CMsd, &fds, NULL, NULL, &tv ) ;
if (FD_ISSET(CMsd, &fds))
{
FD_CLR(CMsd,&fds);
char* rcvBuffer = new char[rcv_length];
long rc=recv(CMsd,rcvBuffer,rcv_length,0); //receive
if(rc!=SOCKET_ERROR)
{
rcvBuffer[0] = CMnr;
sendto(svr->sd, (char*)rcvBuffer, rcv_length, 0, (struct sockaddr*)&svr->server, sizeof(svr->server)) != (int)sizeof(rcvBuffer); //send
}
if(rcvBuffer)
delete [] rcvBuffer;
}
}
The UDP server to send to the Java application is initialized as follows:
void UDPServer::startUDPServer(){
if (WSAStartup(0x0101, &w) != 0)
{
fprintf(stderr, "Could not open Windows connection.\n");
exit(0);
}
sd = socket(AF_INET, SOCK_DGRAM, 0);
if (sd == INVALID_SOCKET)
{
fprintf(stderr, "Could not create socket.\n");
WSACleanup();
exit(0);
}
server.sin_family = AF_INET;
server.sin_port = htons(port_number);
server.sin_addr.s_addr = inet_addr("127.0.0.1");
if (connect(sd, (struct sockaddr *)&server, sizeof(struct sockaddr_in)) == -1)
{
fprintf(stderr, "Could not connect name to socket.\n");
stopUDPServer();
}
}
The main calls
UDPServer* udpsvr;
udpsvr = new UDPServer;
udpsvr->startUDPServer();
while(1){
CM->updateData(udpsvr, CMid);
}
Any help would be appreciated why i get that much delay.
The data received from the Java app is correct but ~1 second delay.
Thank you,
Regards
Don't use bind() on client. Use connect().
Summing up, for UDP:
Server:
socket()
bind()
Client:
socket()
connect()
Example of code for server:
// socket()
fd_ = socket(AF_INET, SOCK_DGRAM, 0);
if (fd_ < 0) {
throw std::runtime_error ("Client socket error");
}
// connect()
struct sockaddr_in serv_addr;
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(port);
struct in_addr addr;
inet_aton(address.c_str(), &addr);
bcopy(&addr, &serv_addr.sin_addr.s_addr, sizeof(addr));
if (connect(fd_, (struct sockaddr *) &serv_addr,
sizeof(serv_addr)) < 0) {
::close(fd_);
throw std::runtime_error ("Client socket error");
}
Example of code for client:
// socket()
fd_ = socket(AF_INET, SOCK_DGRAM, 0);
if (fd_ < 0) {
throw std::runtime_error ("Client socket error");
}
// connect()
struct sockaddr_in serv_addr;
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(port);
struct in_addr addr;
inet_aton(address.c_str(), &addr);
bcopy(&addr, &serv_addr.sin_addr.s_addr, sizeof(addr));
if (connect(fd_, (struct sockaddr *) &serv_addr,
sizeof(serv_addr)) < 0) {
::close(fd_);
throw std::runtime_error ("Client socket error");
}
Finally, you may want to have a look at flushing UDP buffers.
I've bumped into a problem with my broadcasting server. basically, I want it to send broadcasts continuously from the moment I launch it. for some reason it will not start until it receives a connection from somewhere. I must have messed up something but I can't realise what.
here is my code:
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
SOCKET sock;
sock = socket(AF_INET, SOCK_DGRAM, 0);
char broadcast = 'a';
if(setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &broadcast, sizeof(broadcast)) < 0)
{
perror("broadcast options");
closesocket(sock);
return 1;
}
struct sockaddr_in Recv_addr;
struct sockaddr_in Sender_addr;
int len = sizeof(struct sockaddr_in);
char recvBuff[50];
int recvBuffLen = 50;
//char sendMsg[] = "broadcast message from salam rofl";
Recv_addr.sin_family = AF_INET;
Recv_addr.sin_port = htons(PORT);
Recv_addr.sin_addr.s_addr = INADDR_ANY;
if(bind(sock, (sockaddr*)&Recv_addr, sizeof(Recv_addr)) < 0)
{
perror("bind");
_getch;
closesocket(sock);
return 1;
}
//recvfrom(sock, recvBuff, recvBuffLen, 0, (sockaddr *)&Sender_addr, &len);
//cout << "\nreceived message: " << recvBuff;
while(1)
{
Sleep(3000);
//_getch();
getTime();
if(sendto(sock, currentTime, strlen(currentTime)+1, 0, (sockaddr *)&Sender_addr, sizeof(Sender_addr)) < 0)
{
perror("borhot send: ");
_getch();
closesocket(sock);
return 0;
}
else cout << "message sent successfully";
}
_getch;
closesocket(sock);
WSACleanup();
return 0;
basically if I remove recvfrom, it will give me a send error ("No error") which simply puzzles me. also, if I send it something with a client, it will start broadcasting, but if I connect with another client, only the first client is receiving the broadcast.
thank you in advance.
I doubt it matters but I'm trying to broadcast the current time.
You are not initializing Sender_Addr so you are not telling sendto() where to actually broadcast to.
Try this instead:
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock == INVALID_SOCKET)
{
perror("socket creation");
_getch;
return 1;
}
BOOL enabled = TRUE;
if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char*)&enabled, sizeof(BOOL)) < 0)
{
perror("broadcast options");
_getch;
closesocket(sock);
return 1;
}
struct sockaddr_in Sender_addr;
Sender_addr.sin_family = AF_INET;
Sender_addr.sin_port = htons(BROADCAST_PORT);
Sender_addr.sin_addr.s_addr = inet_addr("Broadcast IP Here");
struct sockaddr_in Recv_addr;
Recv_addr.sin_family = AF_INET;
Recv_addr.sin_port = htons(PORT);
Recv_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(sock, (sockaddr*)&Recv_addr, sizeof(Recv_addr)) < 0)
{
perror("bind");
_getch;
closesocket(sock);
return 1;
}
while(1)
{
Sleep(3000);
getTime();
if (sendto(sock, currentTime, strlen(currentTime)+1, 0, (sockaddr *)&Sender_addr, sizeof(Sender_addr)) < 0)
{
perror("borhot send: ");
_getch();
closesocket(sock);
return 0;
}
cout << "message sent successfully";
}
_getch;
closesocket(sock);
WSACleanup();
return 0;
Looks like your Sender_addr is never being initialized, thus when you remove the recvfrom you're getting an error, and when the recvfrom is in place it's getting populated with the address of the first client to connect (but never being updated).
If you don't know the addresses of the clients that you want to broadcast to, you'll need to setup some handshake where they send you a ping, you receive it with recvfrom, and you store their address in a list or something. Then, when you broadcast, you need to send your message to every client address in the list.
Using sockets, I am not sure how to set the timeout?
thanks
int sock, connected, bytes_recieved;
char send_data [128] , recv_data[128];
SOCKADDR_IN server_addr,client_addr;
int sin_size;
int j = 0;
::socket(AF_INET, SOCK_STREAM, 0);
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(4000);
server_addr.sin_addr.s_addr = INADDR_ANY;
::bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
::listen(sock, 5);
::fflush(stdout);
while(1)
{
sin_size = sizeof(struct sockaddr_in);
connected = ::accept(sock, (struct sockaddr *)&client_addr, &sin_size);
while (1)
{
j++;
::send(connected, send_data, strlen(send_data), 0);
//dealing with lost communication ?
//and reastablishing communication
//set timeout and reset on timeout error
}
}
::closesocket(sock);
You need to use setsockopt to set the SO_SNDTIMEO and/or SO_RCVTIMEO options.
A socket is in blocking mode by default. If you switch it to non-blocking mode using ioctlsocket(FIONBIO), you can use select() to manage timeouts:
SOCKET sock, connected;
int bytes_recieved;
char send_data [128] , recv_data[128];
SOCKADDR_IN server_addr,client_addr;
int sin_size;
int j = 0, ret;
fd_set fd;
timeval tv;
sock = ::socket(AF_INET, SOCK_STREAM, 0);
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(4000);
server_addr.sin_addr.s_addr = INADDR_ANY;
::bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
::listen(sock, 1);
::fflush(stdout);
u_long nbio = 1;
::ioctlsocket(sock, FIONBIO, &nbio);
while(1)
{
FD_ZERO(&fd);
FD_SET(sock, &fd);
tv.tv_sec = 5;
tv.tv_usec = 0;
if (select(0, &fd, NULL, NULL, &tv) > 0)
{
sin_size = sizeof(struct sockaddr_in);
connected = ::accept(sock, (struct sockaddr *)&client_addr, &sin_size);
nbio = 1;
::ioctlsocket(connected, FIONBIO, &nbio);
while (1)
{
j++;
if (::send(connected, send_data, strlen(send_data), 0) < 0)
{
//dealing with lost communication ?
//and reastablishing communication
//set timeout and reset on timeout error
if (WSAGetLastError() == WSAEWOULDBLOCK)
{
FD_ZERO(&fd);
FD_SET(connected, &fd);
tv.tv_sec = 5;
tv.tv_usec = 0;
if (select(0, NULL, &fd, NULL, &tv) > 0)
continue;
}
break;
}
}
closesocket(connected);
}
}
you can use:
fd_set fd;
timeval tv;
FD_ZERO(&fd);
FD_SET(sock, &fd);
tv.tv_sec = time_out(second);
tv.tv_usec = 0;
to set timeout for sending,receiving data.