我正在尝试使用此代码：
#include <stdio.h>
#include <tchar.h>
#include <iostream>
#include <WinSock2.h>
#pragma comment( lib, "ws2_32.lib" )
#include <Windows.h>
using namespace std;
int port = 5012;
SOCKET listen_sock;
SOCKET client_sock;
char FR_recv_buf [1048576] = "";
char recv_buf [102400] = "";
int Receive();
int Listen();
//function to initialize winsock
bool InitializeWinsock()
{
WSADATA wsaData;
int iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if(iResult != 0)
{
cout << "WSAStartup failed with error: " << iResult << endl;
return false;
}
else
{
cout << "WSAStartup successfully initialized." << endl;
return true;
}
}
int ForwardResponse()
{
if (send(client_sock, FR_recv_buf, sizeof(FR_recv_buf), 0) == SOCKET_ERROR)
{
cout << "Forward Response: send() failed with error: " << WSAGetLastError() << endl;
closesocket(client_sock);
//WSACleanup();
return 0;
}
else
{
cout << "Forward Response: send() success.\n";
//go back to begginning again?
Receive();
//CreateThread(0,0,(LPTHREAD_START_ROUTINE)Receive, 0, 0 ,0);
}
}
//Function to parse hostname from http request
string ParseHostname(char * buf)
{
size_t pos;
//string to hold hostname substring
string hostname_t;
//copy request to string for easier parsing
string httpheader = buf;
pos = httpheader.find("Host: ");//find "Host: " line
hostname_t = httpheader.substr(pos + 6);//copy to substring, not including "Host: ", just the hostname
pos = hostname_t.find("\r\n");// find end of line
hostname_t.erase(pos);//erase the rest of the string which is unwanted
return hostname_t;
}
//Function to forward HTTP request from browser to webserver
int ForwardRequest()
{
int bytes_received;
SOCKADDR_IN Dest;
SOCKET frecv_sock;
hostent *Host;
//parse hostname from http request
string hostname = ParseHostname(recv_buf);
if((Host=gethostbyname(hostname.c_str()))==NULL)
{
DWORD dwError = WSAGetLastError();
if (dwError != 0)
{
if(dwError == WSAHOST_NOT_FOUND)
{
cout << "Host " << hostname.c_str() << " not found.\n";
WSACleanup();
return FALSE;
}
else if (dwError == WSANO_DATA)
{
cout << "No data record found.\n";;
WSACleanup();
return FALSE;
}
else
{
cout << "Function failed with error: " << dwError << endl;
WSACleanup();
return FALSE;
}
}
}
else
{
cout << "Successfully connected to host: " << hostname.c_str() << endl;
//privmsg(wsockdl.sock,sendbuf,curchan);
}
Dest.sin_family=AF_INET;
Dest.sin_port=htons(80);
memcpy(&Dest.sin_addr,Host->h_addr,Host->h_length);
// Create a SOCKET for connecting to server
if((frecv_sock = socket(AF_INET,SOCK_STREAM,0))==INVALID_SOCKET)
{
cout << "Forward Request: Error at socket(), error code: " << WSAGetLastError() << endl;
closesocket(frecv_sock);
WSACleanup();
return FALSE;
}
// Connect to server
if(connect( frecv_sock,(SOCKADDR*)&Dest,sizeof(Dest))==SOCKET_ERROR)
{
cout << "Forward Request: connect() failed, error code: " << WSAGetLastError() << endl;
closesocket( frecv_sock);
WSACleanup();
return FALSE;
}
//send intercepted request to server
if (send(frecv_sock, recv_buf, strlen(recv_buf), 0) == SOCKET_ERROR)
{
cout << "Forward Request: send() failed with error: " << WSAGetLastError() << endl;
closesocket(frecv_sock);
WSACleanup();
return 0;
}
else
{
cout << "Forward Request: send() success.\n";
}
//receive request from server
do{
bytes_received = recv(frecv_sock,FR_recv_buf,sizeof(FR_recv_buf),0);
if (bytes_received > 0){
strcat (FR_recv_buf, "\0");
cout << "Forward Request: recv() success. Bytes received: " << bytes_received << endl;
CreateThread(0, 0, (LPTHREAD_START_ROUTINE)ForwardResponse, 0 ,0 ,0);
//ForwardResponse();
}
else if ( bytes_received == 0 ){
cout << "Forward Request: Connection closed\n";
closesocket(frecv_sock);
}
else if ( bytes_received == SOCKET_ERROR){
cout << "Forward Request: recv() failed with error: " << WSAGetLastError() << endl;
closesocket(frecv_sock);
WSACleanup();
return 0;
}
}while (bytes_received > 0);
}
//Function to accept connection and receive data from browser
int Receive()
{
SOCKADDR_IN csin;
int csin_len = sizeof(csin);
int iResult;
//accept client connection
client_sock = accept(listen_sock , (LPSOCKADDR)&csin, &csin_len);//pauses here to wait for connection from client
if (client_sock == INVALID_SOCKET) {
cout << "accept failed with error: "<< WSAGetLastError() << endl;
closesocket(client_sock);
WSACleanup();
return 1;
}
else{
cout << "Client connection from IP: " << inet_ntoa(csin.sin_addr) << ":" << csin.sin_port << endl;
}
CreateThread(0, 0 , (LPTHREAD_START_ROUTINE)Receive, 0 , 0 ,0); //Start another thread to accept.
do {
iResult = recv(client_sock, recv_buf, sizeof(recv_buf), 0);
if (iResult == SOCKET_ERROR) {
closesocket(client_sock);
WSACleanup();
cout << "Receive: recv() failed with error: "<< WSAGetLastError() << endl;
}
else if (iResult > 0){
//null terminate receive buffer
//recv_buf[iResult] = '\0';
strcat(recv_buf, "\0");
cout <<"Receive: Bytes received: " << iResult << endl;
//forward HTTP request from browser to web server
cout << recv_buf << endl;
HANDLE pChildThread = CreateThread(0, 0 , (LPTHREAD_START_ROUTINE)ForwardRequest, 0 , 0 ,0);
WaitForSingleObject(pChildThread,60000); //Wait for connection between proxy and remote server
CloseHandle(pChildThread);
}
else if ( iResult == 0 ){
cout << "Receive: Connection closed\n";
}
}while ( iResult > 0 );
return 0;
}
//Function which listens for incoming connections to the proxy
int Listen()
{
SOCKADDR_IN local;
memset(&local,0,sizeof(local));
local.sin_family = AF_INET;
local.sin_port = htons(port);
local.sin_addr.s_addr = INADDR_ANY;
//create socket for listening to
listen_sock = socket(AF_INET, SOCK_STREAM, 0);
//bind function associates a local address with a socket.
if (bind(listen_sock, (LPSOCKADDR)&local, sizeof(local)) == 0)
{
if (listen(listen_sock, 10) == 0)
{
cout << "Listening on: " << port << endl;
}
else
{
cout << "Error listening on socket.\n";
}
}
else{
cout << "bind() failed with error: "<< WSAGetLastError() << endl;
}
//accept and start receiving data from broswer
CreateThread(0, 0 , (LPTHREAD_START_ROUTINE)Receive, 0 , 0 ,0);
return 0;
}
int CloseServer()
{
closesocket(client_sock);
WSACleanup();
return 1;
}
int _tmain(int argc, _TCHAR* argv[])
{
InitializeWinsock();
Listen();
cin.get();
return 0;
}
但似乎连接过早结束，或者recv()或send()函数失败。除了无法连接外，我的浏览器上没有显示任何内容。有谁能发现问题？
答案 0 :(得分：4)
一个主要问题是您只有一个客户端套接字。您创建的每个线程共享相同的客户端套接字，因此如果在第一个连接完成之前建立了两个连接，则第一个套接字将使用第二个连接覆盖。请记住，线程共享进程中的所有内存，包括全局变量等内容。
编辑：由于您使用的是C ++，为什么不在类中封装变量和函数？而不是像你一样静态地为缓冲区分配内存，而是使用new在堆上创建它们。
简单的多线程服务器：
class Connection
{
public:
Connection()
: buffer(0), buffer_size(0)
{ }
void run(SOCKET sock);
privat:
SOCKET input_socket; // Socket we read from
SOCKET output_socket; // Socket we write to
char *buffer; // Buffer we read data into, and write data from
size_t buffer_size; // Total size of buffer (allocated memory)
size_t read_size; // Number of bytes read
void connect();
void recv();
void send();
};
void Connection::run(SOCKET sock)
{
input_socket = sock;
if (buffer == 0)
{
// Allocate buffer
}
// Connect to the real server
connect();
for (;;)
{
try
{
recv();
send();
}
catch (exception &e)
{
std::cerr << "Error: " << e.what() << '\n';
break;
}
}
// Clean up
delete [] buffer;
closesocket(output_socket);
closesocket(input_socket);
}
void Connection::recv()
{
// Read data into the buffer, setting "read_size"
// Like: read_size = recv(input_socket, buffer_size, 0);
// Throw exception on error (includes connection closed)
// NOTE: If error is WSAEWOULDBLOCK, set read_size to 0, don't throw exception
}
void Connection::send()
{
if (read_size > 0)
{
// Send data from the buffer
// Like: send(output_socket, buffer, read_size, 0))
// Throw exception on error
}
}
void Connection::connect()
{
// Connect to the real server
// Set the output_socket member variable
}
DWORD client_thread(LPVOID param)
{
SOCKET socket = (SOCKET) param;
// Make socket nonblocking
int mode = 1;
ioctlsocket(socket, FIONBIO, &mode)
// Main thread stuff
Connection connection;
connection.run(socket);
}
int main()
{
// Create master socket, and other initialization
for (;;)
{
SOCKET client_socket = accept(...);
CreateThread(0, 0 , (LPTHREAD_START_ROUTINE) client_thread,
(LPVOID) client_socket , 0 ,0);
}
// Clean up
}
答案 1 :(得分：0)
另一个主要问题是你正在将'\ 0'附加到接收缓冲区，显然期望send（）将识别它并停止从那里发送，即使send（）的size参数是sizeof（FR_recv_buf） ，这才是真正的尊重。另一个问题是FR_recv_buf等数据项是实例变量而不是局部变量，因此无法处理多重并发连接。