This is my first time coding something using WinSock2 and I tried making a simple chat program which should detect if the server disconnected and then should try to reconnect until a successful connection has been made. (Also: the client connects to server via a No-IP DNS) This is the code:
main.cpp:
void keepAliveSEND(const char* IP, int port) {
TCPClient ack(IP, port);
ack.connecttcp();
while (true) {
ack.synchronizeSEND();
ack.synchronizeGET();
}
}
void keepAliveGET(TCPClient* client, const char* IP, int port) {
TCPClient ack(IP, port);
ack.connecttcp();
unsigned long nonblock = 1;
ioctlsocket(ack.ssocket, FIONBIO, &nonblock);
while (true) {
auto t1 = std::chrono::high_resolution_clock::now();
bool loop = true;
bool timeout = true;
while (loop) {
char recvbuff[1024];
int ByteReceived = 0;
ByteReceived = recv(ack.ssocket, recvbuff, sizeof(recvbuff), 0);
if (ByteReceived > 0) {
std::string str = "";
for (int i = 0; i < ByteReceived; i++) {
str += recvbuff[i];
}
timeout = false;
}
auto t2 = std::chrono::high_resolution_clock::now();
auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1);
long ldur = duration.count();
if (ldur >= 2000) {
loop = false;
if (timeout) {
client->reconnect();
ack.reconnect();
}
}
}
ack.synchronizeSEND();
}
}
int main() {
using namespace std;
TCPClient client(DNS, 4444);
client.connecttcp();
thread t(keepAliveGET, &client, DNS, 4443);
thread t2(keepAliveSEND, DNS, 4442);
while (true) {
//Chat-Code only active upon succesful connection and startchat-command from user
}
return 0;
}
TCPClient.cpp:
void TCPClient::connecttcp() {
WSAStartup(MAKEWORD(2, 2), &wsaData);
ADDRINFO hints;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
ADDRINFO *res;
getaddrinfo(HostIP, NULL, &hints, &res);
char ipbuf[INET_ADDRSTRLEN];
InetNtop(AF_INET, &((SOCKADDR_IN*)res->ai_addr)->sin_addr, ipbuf, sizeof(ipbuf));
this->IP = ipbuf;
ssocket = WSASocketW(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, NULL, NULL);
ServerAddr.sin_family = AF_INET;
ServerAddr.sin_port = htons(port);
InetPton(AF_INET, (PCSTR)IP, &ServerAddr.sin_addr.s_addr);
while (connect(ssocket, (SOCKADDR*)&ServerAddr, sizeof(ServerAddr)) == SOCKET_ERROR) {
Sleep(1000);
}
}
void TCPClient::reconnect() {
closesocket(ssocket); //EDIT1: Added this line, doesn't change anything
while (connect(ssocket, (SOCKADDR*)&ServerAddr, sizeof(ServerAddr)) == SOCKET_ERROR) {
Sleep(1000);
}
}
void TCPClient::synchronizeSEND() {
sendData("ACK");
}
void TCPClient::synchronizeGET() {
while (true) {
std::string Ack = receiveData(3);
if (Ack == "ACK") {
return;
}
}
}
void TCPClient::closeConnection() {
closesocket(ssocket);
WSACleanup();
}
When the server closes and then starts again it will listen on port 4444,4443&4442 for ingoing connections and this is why I want to call connect() to reconnect.
When connecttcp() is called for the first time (upon execution) only 0.9MB RAM are being used up by this process. But as soon as the server disconnects and thus reconnect() is called the RAM starts rising quite a bit reaching almost 1.5GB in about 15 seconds which is not acceptable behaviour. I tried to debug the code in Visual Studio an it seems that connect(ssocket, (SOCKADDR*)&ServerAddr, sizeof(ServerAddr)) is causing the memory to go up. But it's still able to reconnect...
I already tried to call closesocket(ssocket) before reconnecting but that didn't help either...
I read somewhere that Winsock waits up to 4min before it frees the connect() resources. Could that be why it behaves like that?
How can I solve this sort of thing?
Related
For my project I am unable to debug the program so i cannot be sure as to why this error occurs.
My server, which is hosted on c# is failing to connect to server on localhost.
Instead of it sending back a "connection" signal to my server, it never connects, I think the code is written well and I can't see any errors, maybe i made a careless mistake somewhere
Also, I HAVE to use gethostbyname instead of getaddrinfo
winsock namespace:
SOCKET WinSock::ConnectToServer(PCHAR IP, USHORT Port)
{
WSADATA WSA;
if (WSAStartup(MAKEWORD(2, 0), &WSA))
{
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s != SOCKET_ERROR)
{
hostent *Host = gethostbyname(IP);
if (Host != ERROR)
{
SOCKADDR_IN Addr;
Addr.sin_family = AF_INET;
Addr.sin_port = htons(Port);
Addr.sin_addr.s_addr = NULL;
if (bind(s, PSOCKADDR(&Addr), sizeof(Addr)) > 0)
{
return s;
}
}
}
}
return FALSE;
}
BOOL WinSock::SendData(SOCKET s, PBYTE Packet)
{
DWORD PacketSize = lstrlenA(PCHAR(Packet));
if (send(s, PCHAR(&PacketSize), 8, 0) > NULL)
{
if (send(s, PCHAR(Packet), PacketSize, 0) > NULL)
{
return TRUE;
}
}
return FALSE;
}
main method:
int main()
{
char key = 1;
SOCKET S = WinSock::ConnectToServer(0, 55480);
while(true)
{
WinSock:SendData(S, (PBYTE)key);
}
}
if (bind(s, PSOCKADDR(&Addr), sizeof(Addr)) > 0)
The description of this code is that it is supposed to connect to a server. But the problem is that bind() does not connect to any server. It only links the socket to a local port. This is what servers that listen on sockets do. This is, presumably, the same port that the server already opened, hence the bind() fails. If the server wasn't listening bind() will, ironically, succeed. But it won't be connect to anything, anyway.
You want to use connect() and not bind().
Additionally, I have to note that if this function creates a socket first, but then fails to establish a connection for this or any other reason it will return an error indication but fail to close the socket, thus leaking a socket descriptor. You must fix this bug, too.
You are not actually making a connection to the server. You are calling bind() to bind the client socket to a local port 55480, but that does not create a connection. You need to instead call connect() to connect the client socket to the remote port 55480.
Also, your SendData() is coded wrong. It is telling send() to send 8 bytes for the PacketSize, but a DWORD is only 4 bytes in size. And send() does not return NULL on failure. And send() is not guaranteed to send all of the requested bytes, so you need to call it in a loop. And it is customary to send multi-byte integers in network byte order (big endian).
Also, you have coded SendData() to expect a null-terminated C-style string, but that is not what your main() is actually passing in to it.
Try something more like this:
bool WinSock::Init()
{
WSADATA WSA;
return (WSAStartup(MAKEWORD(2, 0), &WSA) == 0);
}
bool WinSock::Cleanup()
{
return (WSACleanup() == 0);
}
SOCKET WinSock::ConnectToServer(const char *IP, unsigned short Port)
{
hostent *Host = gethostbyname(IP);
if ((Host != NULL) && (Host->h_addrtype == AF_INET)
{
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s != INVALID_SOCKET)
{
SOCKADDR_IN Addr = {};
Addr.sin_family = AF_INET;
Addr.sin_port = htons(Port);
Addr.sin_addr.s_addr = * (u_long*) Host->h_addr;
if (connect(s, PSOCKADDR(&Addr), sizeof(Addr)) != SOCKET_ERROR)
{
return s;
}
closesocket(s);
}
}
return INVALID_SOCKET;
}
bool WinSock::Close(SOCKET s)
{
return (closesocket(s) == 0);
}
bool WinSock::SendData(SOCKET s, const void* Data, DWORD DataSize)
{
const char *ptr = (const char*) Data;
while (DataSize > 0)
{
int numSent = send(s, ptr, DataSize, 0);
if (numSent == SOCKET_ERROR) return false;
ptr += numSent;
DataSize -= numSent;
}
return true;
}
bool WinSock::SendData(SOCKET s, const char *Packet)
{
DWORD PacketSize = lstrlenA(Packet);
DWORD tmp = htonl(PacketSize);
if (!SendData(s, &tmp, sizeof(tmp)) return false;
return SendData(s, Packet, PacketSize);
}
int main()
{
if (WinSock::Init())
{
const char *key = "1";
SOCKET S = WinSock::ConnectToServer(NULL, 55480);
if (s != INVALID_SOCKET)
{
while (true)
{
WinSock:SendData(S, key);
}
WinSock::Close(s);
}
WinSock::Cleanup();
}
return 0;
}
What I'm trying to do is a forking proxy that deals HTTP(S) connections: while GET (without SSL) requests are successfully executed and the contents are delivered to the client, when it comes to CONNECT method things are not going well, since connect()ing to the remote server may not immediately succeeds: in fact, it nevers succeeds.
I tried for a non blocking socket connected to the remote server, so I can see if connect() goes immediately or takes some time: in the second case, I'd call select() to see when the remote server is ready to send data to me: yet, connect() never connects.
Here's my proxy main() code:
int main(int argc, char *argv[]) {
// ClientManager.cpp is described below
ClientManager cm;
//listening on port given by argv
if (cm.startListeningForClient(listening_port)) {
while(true) {
int new_client_socket = cm.acceptConnectionFromClient();
if (new_client_socket >= 0) {
cm.forkAndManageClient();
}
else {
perror("accept error");
}
}
} else {
perror("Error on start listening");
}
return EXIT_SUCCESS;
}
Now follows, with some omissis not involved with my issue, ClientManager.cpp, whose functions are called in main() above:
ClientManager::ClientManager() {
sockfd_client = -1; // socket connected to client
new_sockfd_client = -1; // socket accepting connection from client
sockfd_server = -1; // socket connected to remote server
}
// error controls omitted
bool ClientManager::startListeningForClient(int port) {
struct sockaddr_in serv_addr;
bzero((char*)&serv_addr,sizeof(serv_addr));
serv_addr.sin_family=AF_INET;
serv_addr.sin_port=htons(port);
serv_addr.sin_addr.s_addr=INADDR_ANY;
sockfd_client = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
bind(sockfd_client,(struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(sockfd_client, 50);
return true;
}
// error controls omitted
int ClientManager::acceptConnectionFromClient(void) {
struct sockaddr_in cli_addr;
unsigned int clilen;
bzero((char*)&cli_addr, sizeof(cli_addr));
clilen = sizeof(cli_addr);
new_sockfd_client = accept(sockfd_client, (struct sockaddr*)&cli_addr, &clilen);
return new_sockfd_client;
}
int ClientManager::forkAndManageClient() {
// getRequestFromClient: the method below receives requests from
// clients and parses the infos I need (i.e. what method,
// hostname of remote server to be resolved, its port, ...)
getRequestFromClient();
// managing the HTTP(S) request by the child process
int pid = fork();
if (pid < 0) {
perror("ERROR on fork");
}
else if (pid > 0) {
// parent process
// do nothing
}
else {
// close immediately the client socket used for accepting new connections from the parent process
close (sockfd_client);
if (!manageRequest()) {
perror("Error managing request from client");
}
// close the connection from the client
close (new_sockfd_client);
new_sockfd_client = -1;
// the child process will terminate now
_exit(EXIT_SUCCESS);
}
return pid;
}
// now the problematic method...
bool ClientManager::manageRequest(void) {
// if this is a CONNECT request
if (rm.isCONNECT()) {
struct sockaddr_in remote_server;
int conn_res;
remote_server.sin_family = AF_INET;
remote_server.sin_addr.s_addr = rm.getServerAddr();
remote_server.sin_port = rm.getServerPort();
fd_set fdset;
struct timeval tv;
sockfd_server = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// make socket not blocking
int flags = fcntl(sockfd_server, F_GETFL, 0);
flags = flags | O_NONBLOCK;
if (fcntl(sockfd_server, F_SETFL, flags) == -1) {
perror("FCNTL:");
}
printf("CONNECT set socket to non-blocking mode\n");
conn_res = connect(sockfd_server, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in));
printf("AFTER CONNECT()\n");
if (conn_res < 0) {
if (errno != EINPROGRESS) {
printf("CONNECT: connect() failed, quitting\n");
return false;
}
}
printf("CONNECT connection is taking place...\n");
// connected immediately
if (conn_res == 0) {
printf("CONNECT connected OK!\n");
goto CONNECTED;
}
FD_ZERO(&fdset);
FD_SET(sockfd_server, &fdset);
tv.tv_sec = 5; // tried 5, 20, 60 seconds, but it always times out
tv.tv_usec = 0;
printf("CONNECT attempting select()\n");
if (select(sockfd_server+1, NULL, &fdset, NULL, &tv) == 0) {
errno = ETIMEDOUT;
close(sockfd_server);
sockfd_server = -1;
return false;
}
if (FD_ISSET(sockfd_server, &fdset)) {
int so_error;
socklen_t len = sizeof so_error;
if (getsockopt(sockfd_server, SOL_SOCKET, SO_ERROR, &so_error, &len) < 0) {
return false;
}
} else {
printf("sockfd_server not set\n");
}
CONNECTED:
fcntl(sockfd_server, F_SETFL, flags &~ O_NONBLOCK);
// yeah, now I will start to deal the HTTPS flow in both directions
return true;
}
}
It does manage setting socket to non blocking mode, and to print CONNECT connection is taking place..., but it always returns Error managing request from client: Connection timed out.
I apologize for posting miles of LOC, but this is what drives me crazy since days, and after reading posts, tutorial and guides, I really don't know what to do.
It connects now to every site which requires an HTTPS connection!
Proper error checking and following closing of socket descriptors were missing. Here's my code:
bool ClientManager::manageRequest(void) {
if (rm.isCONNECT()) {
struct sockaddr_in remote_server, local_bind;
int conn_res, select_res;
memset(&remote_server, 0, sizeof(remote_server));
remote_server.sin_family = AF_INET;
remote_server.sin_addr.s_addr = rm.getServerAddr();
remote_server.sin_port = rm.getServerPort();
memset(&local_bind, 0, sizeof(local_bind));
local_bind.sin_family = AF_INET;
local_bind.sin_addr.s_addr = htonl(INADDR_ANY);
local_bind.sin_port = htons(0);
fd_set rdset, wrset;
struct timeval tv;
sockfd_server = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sockfd_server < 0) {
perror("socket: ");
}
if(!setNonBlocking(sockfd_server))
perror("fcntl");
debug_green("CONNECT set socket to non-blocking mode\n");
bind(sockfd_server, (struct sockaddr*) &local_bind, sizeof(local_bind));
conn_res = connect(sockfd_server, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in));
// The socket is nonblocking and the connection cannot be completed immediately
// check for EINPROGRESS
if ((conn_res == -1) && (errno != EINPROGRESS)) {
FD_ZERO(&rdset);
FD_SET(sockfd_server, &rdset);
wrset = rdset;
tv.tv_sec = 0;
tv.tv_usec = 0;
debug_yellow("CONNECT attempting select()\n");
do {
select_res = select(sockfd_server+1, &rdset, &wrset, NULL, &tv);
} while ((select_res == -1) && (errno == EINTR));
if ((!FD_ISSET(sockfd_server, &rdset)) && ((!FD_ISSET(sockfd_server, &wrset)))) {
debug_red("SELECT sockfds not responding\n");
close(sockfd_server);
sockfd_server = -1;
return false;
}
conn_res = connect(sockfd_server, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in));
if (conn_res == -1) {
if(errno == EISCONN)
printf ("connect(): connections already existing, OK\n");
else {
printf("connect() for safety check: connection NOT successfull\n");
close(sockfd_server);
sockfd_server = -1;
return false;
}
}
printf("connection OK\n");
fflush(stdout);
} else {
debug_green("Connection immediately OK\n");
fflush(stdout);
}
if (!setBlocking(sockfd_server)) {
perror("FCNTL:");
}
debug_green("CONNECT set socket back to blocking mode\n");fflush(stdout);
}
return true;
}
Functions setting blocking or non blocking socket:
bool ClientManager::setNonBlocking(int sockfd) {
printf("setting non block socket\n"); fflush(stdout);
int flags;
if ((flags = fcntl(sockfd, F_GETFL, 0)) < 0)
return false;
flags |= O_NONBLOCK;
if (fcntl(sockfd, F_SETFL, flags) < 0)
return false;
return true;
}
bool ClientManager::setBlocking(int sockfd) {
printf("setting block socket\n"); fflush(stdout);
int flags;
if ((flags = fcntl(sockfd, F_GETFL, 0)) < 0)
return false;
flags &= (~O_NONBLOCK);
if (fcntl(sockfd, F_SETFL, flags) < 0)
return false;
return true;
}
Debug functions:
#define DEFAULTCOLOR "\033[0m"
#define RED "\033[22;31m"
#define YELLOW "\033[1;33m"
#define GREEN "\033[0;0;32m"
#define debug_red(...) std::cout << RED << __VA_ARGS__ << DEFAULTCOLOR; fflush(stdout);
#define debug_yellow(...) std::cout << YELLOW << __VA_ARGS__ << DEFAULTCOLOR; fflush(stdout);
#define debug_green(...) std::cout << GREEN << __VA_ARGS__ << DEFAULTCOLOR; fflush(stdout);
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.
back again (sorry)
I've created a socket C++ application, but it isn't working properly.
This is my first code:
void Network::Start()
{
this->socket = Env::GetSocket();
SOCKADDR_IN sInformation;
sInformation.sin_family = AF_INET;
sInformation.sin_addr.s_addr = INADDR_ANY;
sInformation.sin_port = htons(30000);
bind(this->socket, (SOCKADDR*) (&sInformation), sizeof(sInformation));
listen(this->socket, 10);
while (true)
{
this->DO();
}
}
And the DO function:
void Network::DO()
{
SOCKET s = SOCKET_ERROR;
sockaddr_in sock_addr;
accept(s, (sockaddr*) &sock_addr, NULL);
if (INVALID_SOCKET == s)
{
return;
}
else
{
cout << "Received connection from " << inet_ntoa(sock_addr.sin_addr);
}
}
What happens, always (even if I connect) the value s is INVALID_SOCKET. I connect via a .SWF but it doesn't accept my connection. What am I doing wrong?
You are not doing adequate error handling, and you are not using accept() correctly. Try this:
void Network::Start()
{
this->socket = Env::GetSocket();
if (this->socket == INVALID_SOCKET)
{
// error
return;
}
SOCKADDR_IN sInformation = {0};
sInformation.sin_family = AF_INET;
sInformation.sin_addr.s_addr = INADDR_ANY;
sInformation.sin_port = htons(30000);
if (bind(this->socket, (SOCKADDR*) &sInformation, sizeof(sInformation)) != 0)
{
// error
return;
}
if (listen(this->socket, 10) != 0)
{
// error
return;
}
while (true)
{
this->DO();
}
}
void Network::DO()
{
SOCKADDR_IN sock_addr = {0};
socklen_t sock_addr_len = sizeof(sock_addr);
SOCKET s = accept(this->socket, (SOCKADDR*) &sock_addr, &sock_addr_len);
if (INVALID_SOCKET == s)
{
return;
}
cout << "Received connection from " << inet_ntoa(sock_addr.sin_addr);
// use s as needed. Don't forget to call close(s) or closesocket(s)
// when finished, depending on your platform...
}
accept takes the listening socket as a parameter, and returns the newly connected socket;
socklen_t length = sizeof(sockaddr_in);
s = accept(this->socket, (sockaddr*) &sock_addr, &length);
EDIT: Just tested the program, with the socket created with AF_INET, SOCK_STREAM and sInformation cleared out;
bzero((char *) &sInformation, sizeof(sInformation));
...it seems to be running well on MacOS X and linux.
Recently I have been working on some client-side code for sending and receiving messages from a server using threading. The below code behaves strangely when run. Upon inputting a message to send to the server, the code completes the task, albeit with a "socket already in use" error, the server gets it. But every subsequent message I attempt to send to the server is not received immediately, yet it is seemingly all received at once when the client program terminates.
(Additionally, I am certain the error is client-side, the strange behavior isn't exhibited if one comments the output function.)
How can I fix this error?
Client
#include <stdio.h>
#include <cstdlib>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <unistd.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <string>
#include <iostream>
#include <errno.h>
#include <pthread.h>
void* input(void* ptr)
{
int on = 1;
bool *input_done = ((struct thread_args*)ptr)->process_done;
struct addrinfo *res = ((struct thread_args*)ptr)->result;
char msg[256];
int sock = socket(res->ai_family,res->ai_socktype,res->ai_protocol);
setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(char *)&on,sizeof(on));
bind(sock,res->ai_addr,res->ai_addrlen);
connect(sock,res->ai_addr,res->ai_addrlen);
cin.getline(msg,256);
if (msg[0] == '/') {exit(1);}
send(sock,msg,sizeof msg,0);
cout << "You:" << msg << endl;
*input_done = 1;
close(sock);
pthread_exit(NULL);
}
void* output(void* ptr)
{
int on = 1;
bool *output_done = ((struct thread_args*)ptr)->process_done;
struct addrinfo *res = ((struct thread_args*)ptr)->result;
char msg[256];
int sock = socket(res->ai_family,res->ai_socktype,res->ai_protocol);
bind(sock,res->ai_addr,res->ai_addrlen);
connect(sock,res->ai_addr,res->ai_addrlen);
recv(sock,msg,sizeof msg,0);
cout << "Recieved:" << msg;
*output_done = 1;
close(sock);
pthread_exit(NULL);
}
void io_client()
{
//thread function variables
pthread_t t1,t2;
bool input_done = 1, output_done = 1;
//socket setup variables
struct addrinfo hints, *res;
memset(&hints,0,sizeof hints);
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
getaddrinfo("localhost","8080",&hints,&res);
//setting up structures to pass data to threaded functions
struct thread_args i_args, o_args;
i_args.result = res; i_args.process_done = &input_done;
o_args.result = res; o_args.process_done = &output_done;
while(1)
{
if (output_done)
{
pthread_create(&t2,NULL,output,&o_args);
output_done = 0;
}
if (input_done)
{
pthread_create(&t1,NULL,input,&i_args);
input_done = 0;
}
}
}
int main()
{
io_client();
}
Server
void server()
{
struct addrinfo hints, *res;
int sock=-1, newsock=-1;
int length, on=1;
char **address_list; int entries = 0;
//fd_set read_fd;
//struct timeval timeout;
char buffer[100];
memset(&hints,0,sizeof hints);
res = NULL;
memset(&res,0,sizeof res);
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
getaddrinfo("localhost","8080",&hints,&res);
sock = socket(res->ai_family,res->ai_socktype,res->ai_protocol);
setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(char *)&on,sizeof(on));
bind(sock,res->ai_addr,res->ai_addrlen);
listen(sock,10);
while(1)
{
struct sockaddr_storage addr;
char ipstr[INET6_ADDRSTRLEN];
socklen_t len;
len = sizeof addr;
newsock = accept(sock,NULL,NULL);
getpeername(newsock,(struct sockaddr*)&addr,&len);
struct sockaddr_in *s = (struct sockaddr_in*)&addr;
inet_ntop(AF_INET,&s->sin_addr,ipstr,sizeof ipstr);
length = 100;
setsockopt(newsock,SOL_SOCKET,SO_RCVLOWAT, (char*)&length,sizeof length);
recv(newsock,buffer,sizeof buffer,0);
cout << buffer << endl;
}
if (newsock != -1)
{
close(newsock);
}
if (sock != -1)
{
close(sock);
}
}
int main()
{
server();
}
It looks like you are trying to have your client bind() to the same port as the server. That's not necessary. And worse, you are trying to bind to to the IP address of the server - which is also a bigger problem. In general, for client sockets that are to call the connect() function, you should just have your socket bind to port 0 and IP 0, thus letting the OS pick a randomly available port for you and enabling use the right local IP address and adapter for the connection. You can call getsockname() to discover what port the OS picked for you after you call connect.
And if you let the OS pick the client port for you, you won't need that SO_REUSESADDR call. Although, your server code could call it for cases where it needs to restart after shutting down with connections still pending to close.
Also. you aren't checking the return value of any of your socket calls. That's probably why you are getting some mysterious results. The call to bind() is more likely failing because you are specifying the server IP, but connect() is succeeding because it will auto-bind the socket if it hasn't already.
Here's a cleaned up version of you input() function. Converting your output() function is an exercise left up to the reader. If you follow my example, you'll be in good shape.
void* input(void* ptr)
{
int on = 1;
bool *input_done = ((struct thread_args*)ptr)->process_done;
int ret;
int success = true;
struct sockaddr_in addrLocal = {};
struct addrinfo *res = ((struct thread_args*)ptr)->result;
char msg[256];
int sock = socket(AF_INET, SOCK_STREAM, 0);
success = (sock != -1);
if (success)
{
addrLocal.sin_family = AF_INET;
addrLocal.sin_port = INADDR_ANY; // INADDR_ANY == 0 --> pick a random port for me
addrLocal.sin_addr.s_addr = INADDR_ANY; // INADDR_ANY == 0 --> use all appropriate network
ret = bind(sock,(sockaddr*)&addrLocal,sizeof(addrLocal));
if (ret == -1) perror("bind: ");
success = (ret != -1);
}
if (success)
{
ret = connect(sock,res->ai_addr,res->ai_addrlen);
if (ret == -1) perror("connect: ");
success = (ret != -1);
}
if (success)
{
cin.getline(msg,256);
if (msg[0] == '/') {exit(1);}
ret = send(sock,msg,sizeof msg,0);
if (ret == -1) perror("send: ");
success = (ret != -1);
}
if (success)
{
cout << "You:" << msg << endl;
*input_done = 1;
}
if (sock != -1)
{
close(sock);
sock = -1;
}
return NULL;
}
I guess that "SO_REUSEADDR" socket option that you are giving is the problem.
Are you calling that function again and again without closing the client socket ? In that case it will not work. The purpose of this socket option is to "reuse the address when the already opened socket for the same address is in TIME_WAIT state else you will get the mentioned error".
If you client is opening a new connection each and every time, then I must say that you will have to structure your code more efficiently and handle the socket closing scenarios as well.