xsocket.cpp

这是和p2p相关的一份源码

// ------------------------------------------------
// File : xsocket.cpp
// Date: 25-mar-2004
// Author: giles
// Desc: 
//		Linux version of ClientSocket. Handles the nitty gritty of actually
//		reading and writing TCP
//		
// (c) 2002-2004 peercast.org
// ------------------------------------------------
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// ------------------------------------------------


#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include "xsocket.h"
#include "stats.h"

#ifdef __APPLE__
#include <netinet/in_systm.h> // for n_long definition
#define MSG_NOSIGNAL 0        // doesn't seem to be defined under OS X
#endif

#include <netinet/ip.h>
#include <netinet/tcp.h>

#define INVALID_SOCKET -1
#define SOCKET_ERROR -1

// --------------------------------------------------
void XClientSocket::init()
{
    LOG_DEBUG("MStartup:  OK");

}

// --------------------------------------------------
bool ClientSocket::getHostname(char *str,unsigned int ip)
{
	hostent *he;

	ip = htonl(ip);

	he = gethostbyaddr((char *)&ip,sizeof(ip),AF_INET);

	if (he)
	{
		strcpy(str,he->h_name);
		return true;
	}else
		return false;
}
// --------------------------------------------------
unsigned int ClientSocket::getIP(char *name)
{

	char szHostName[256];

	if (!name)
	{
		if (gethostname(szHostName, sizeof(szHostName))==0)
			name = szHostName;
		else
			return 0;
	}

	hostent *he = XClientSocket::resolveHost(name);

	if (!he)
		return 0;


	char* lpAddr = he->h_addr_list[0];
	if (lpAddr)
	{
		struct in_addr  inAddr;
		memmove (&inAddr, lpAddr, 4);

		return ntohl(inAddr.s_addr);
	}
	return 0;
}
// --------------------------------------------------
void XClientSocket::setLinger(int sec)
{
	linger linger;
	linger.l_onoff = (sec>0)?1:0;
    linger.l_linger = sec;

	if (setsockopt(sockNum, SOL_SOCKET, SO_LINGER, (const char *)&linger, sizeof (linger)) == -1) 
		throw SockException("Unable to set LINGER");
}

// --------------------------------------------------
void XClientSocket::setNagle(bool on)
{
     int nodelay = (on==false);
     if (setsockopt(sockNum, IPPROTO_TCP, TCP_NODELAY, (void*) &nodelay,sizeof(nodelay)) < 0)
		throw SockException("Unable to set NODELAY");
}      
// --------------------------------------------------
void XClientSocket::setBlocking(bool block)
{
	int fl = fcntl(sockNum,F_GETFL);

	if (block)
		fl &= ~O_NONBLOCK;
	else
		fl |= O_NONBLOCK;

	fcntl(sockNum, F_SETFL, fl);
}

// --------------------------------------------------
void XClientSocket::setReuse(bool yes)
{

	unsigned long op = yes ? 1 : 0;
	if (setsockopt(sockNum,SOL_SOCKET,SO_REUSEADDR,(char *)&op,sizeof(op)) < 0) 
		throw SockException("Unable to set REUSE");
}

// --------------------------------------------------
hostent *XClientSocket::resolveHost(char *hostName)
{
	hostent *he;

	if ((he = gethostbyname(hostName)) == NULL)
	{
		// if failed, try using gethostbyaddr instead

		unsigned long ip = inet_addr(hostName);
		
		if (ip == INADDR_NONE)
			return NULL;

		if ((he = gethostbyaddr((char *)&ip,sizeof(ip),AF_INET)) == NULL)
			return NULL;	
	}
	return he;
}
// --------------------------------------------------
void XClientSocket::open(Host &rh)
{


	sockNum = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);

	if (sockNum == INVALID_SOCKET)
		throw SockException("Can`t open socket");

	setBlocking(false);

#ifdef DISABLE_NAGLE
	setNagle(false);
#endif

	host = rh;

	memset(&remoteAddr,0,sizeof(remoteAddr));

	remoteAddr.sin_family = AF_INET;
	remoteAddr.sin_port = htons(host.port);
	remoteAddr.sin_addr.s_addr = htonl(host.ip);

}
// --------------------------------------------------
void XClientSocket::checkTimeout(bool r, bool w)
{
    int err = errno;
    if ((err == EAGAIN) || (err == EINPROGRESS))
    {
		//LOG("checktimeout %d %d",(int)r,(int)w);

		timeval timeout;
		fd_set read_fds;
		fd_set write_fds;

		timeout.tv_sec = 0;
		timeout.tv_usec = 0;

        FD_ZERO (&write_fds);
		if (w)
		{
			timeout.tv_sec = (int)this->writeTimeout/1000;
			FD_SET (sockNum, &write_fds);
		}

        FD_ZERO (&read_fds);
		if (r)
		{
			timeout.tv_sec = (int)this->readTimeout/1000;
	        FD_SET (sockNum, &read_fds);
		}

		int r=select (sockNum+1, &read_fds, &write_fds, NULL, &timeout);

        if (r == 0)
			throw TimeoutException();
		else if (r == SOCKET_ERROR)
			throw SockException("select failed.");

	}else{
		char str[32];
		sprintf(str,"Closed: %s",strerror(err));
		throw SockException(str);
	}
}

// --------------------------------------------------
void XClientSocket::connect()
{
	if (::connect(sockNum,(struct sockaddr *)&remoteAddr,sizeof(remoteAddr)) == SOCKET_ERROR)
		checkTimeout(false,true);
}
// --------------------------------------------------
int XClientSocket::read(void *p, int l)
{
	int bytesRead=0;
	while (l)
	{
		int r = recv(sockNum, (char *)p, l, MSG_NOSIGNAL);
		if (r == SOCKET_ERROR)
		{
			// non-blocking sockets always fall through to here
			checkTimeout(true,false);

		}else if (r == 0)
		{
			throw SockException("Closed on read");
		}else
		{
			stats.add(Stats::BYTESIN,r);
			if (host.localIP())
				stats.add(Stats::LOCALBYTESIN,r);
			updateTotals(r,0);
			bytesRead+=r;
			l -= r;
			p = (char *)p+r;
		}
	}

	return bytesRead;
}


// --------------------------------------------------
void XClientSocket::write(const void *p, int l)
{
	while (l)
	{
		int r = send(sockNum, (char *)p, l, MSG_DONTWAIT|MSG_NOSIGNAL);
		if (r == SOCKET_ERROR)
		{
			// non-blocking sockets always fall through to here
			checkTimeout(false,true);
		}else if (r == 0)
		{
			throw SockException("Closed on write");
		}else
		{
			stats.add(Stats::BYTESOUT,r);
			if (host.localIP())
				stats.add(Stats::LOCALBYTESOUT,r);
			updateTotals(0,r);
			l -= r;
			p = (char *)p+r;
		}
	}
}


// --------------------------------------------------
void XClientSocket::bind(Host &h)
{
	struct sockaddr_in localAddr;

	if ((sockNum = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1)
		throw SockException("Can`t open socket");

	setReuse(true);

	memset(&localAddr,0,sizeof(localAddr));
	localAddr.sin_family = AF_INET;
	localAddr.sin_port = htons(h.port);
	localAddr.sin_addr.s_addr = INADDR_ANY;

	if( ::bind (sockNum, (sockaddr *)&localAddr, sizeof(localAddr)) == -1)
		throw SockException("Can`t bind socket");

	if (::listen(sockNum,SOMAXCONN))
		throw SockException("Can`t listen");

	host = h;
}
// --------------------------------------------------
ClientSocket *XClientSocket::accept()
{

	socklen_t fromSize = sizeof(sockaddr_in);
	sockaddr_in from;

	int conSock = ::accept(sockNum,(sockaddr *)&from,&fromSize);


	if (conSock ==  INVALID_SOCKET)
		return NULL;

	
    XClientSocket *cs = new XClientSocket();
	cs->sockNum = conSock;

	cs->host.port = from.sin_port;
	cs->host.ip = ntohl(from.sin_addr.s_addr);

	cs->setBlocking(false);

#ifdef DISABLE_NAGLE
	cs->setNagle(false);
#endif

	return cs;
}

// --------------------------------------------------
Host XClientSocket::getLocalHost()
{
	struct sockaddr_in localAddr;

	socklen_t len = sizeof(localAddr);
    if (getsockname(sockNum, (sockaddr *)&localAddr, &len) == 0)
		return Host(ntohl(localAddr.sin_addr.s_addr),0);
	else
		return Host(0,0);
}
// --------------------------------------------------
void XClientSocket::close()
{
	if (sockNum)
	{
//		setBlocking(true);
//		setLinger(30);

		shutdown(sockNum,SHUT_RDWR);
		::close(sockNum);

		sockNum = 0;
	}
}

// --------------------------------------------------
bool	XClientSocket::readReady()
{
	timeval timeout;
	fd_set read_fds;
	fd_set write_fds;

	timeout.tv_sec = 0;
	timeout.tv_usec = 0;

    FD_ZERO (&read_fds);
    FD_SET (sockNum, &read_fds);

	return select (sockNum+1, &read_fds, NULL, NULL, &timeout) == 1;
}