util_sock.c

samba-3.0.22.tar.gz 编译smb服务器的源码

	
	/* Set initial timeout */
	timeout.tv_sec = (time_t)(time_out / 1000);
	timeout.tv_usec = (long)(1000 * (time_out % 1000));
	
	for (nread=0; nread < mincnt; ) {      
		FD_ZERO(&fds);
		FD_SET(fd,&fds);
		
		selrtn = sys_select_intr(fd+1,&fds,NULL,NULL,&timeout);
		
		/* Check if error */
		if (selrtn == -1) {
			/* something is wrong. Maybe the socket is dead? */
			if (fd == client_fd) {
				/* Try and give an error message saying what client failed. */
				DEBUG(0,("read_socket_with_timeout: timeout read for client %s. select error = %s.\n",
					client_ip_string, strerror(errno) ));
			} else {
				DEBUG(0,("read_socket_with_timeout: timeout read. select error = %s.\n", strerror(errno) ));
			}
			smb_read_error = READ_ERROR;
			return -1;
		}
		
		/* Did we timeout ? */
		if (selrtn == 0) {
			DEBUG(10,("read_socket_with_timeout: timeout read. select timed out.\n"));
			smb_read_error = READ_TIMEOUT;
			return -1;
		}
		
		readret = sys_read(fd, buf+nread, maxcnt-nread);
		
		if (readret == 0) {
			/* we got EOF on the file descriptor */
			DEBUG(5,("read_socket_with_timeout: timeout read. EOF from client.\n"));
			smb_read_error = READ_EOF;
			return -1;
		}
		
		if (readret == -1) {
			/* the descriptor is probably dead */
			if (fd == client_fd) {
				/* Try and give an error message saying what client failed. */
				DEBUG(0,("read_socket_with_timeout: timeout read to client %s. read error = %s.\n",
					client_ip_string, strerror(errno) ));
			} else {
				DEBUG(0,("read_socket_with_timeout: timeout read. read error = %s.\n", strerror(errno) ));
			}
			smb_read_error = READ_ERROR;
			return -1;
		}
		
		nread += readret;
	}
	
	/* Return the number we got */
	return (ssize_t)nread;
}

/****************************************************************************
 Read data from the client, reading exactly N bytes. 
****************************************************************************/

ssize_t read_data(int fd,char *buffer,size_t N)
{
	ssize_t ret;
	size_t total=0;  
 
	smb_read_error = 0;

	while (total < N) {
		ret = sys_read(fd,buffer + total,N - total);

		if (ret == 0) {
			DEBUG(10,("read_data: read of %d returned 0. Error = %s\n", (int)(N - total), strerror(errno) ));
			smb_read_error = READ_EOF;
			return 0;
		}

		if (ret == -1) {
			if (fd == client_fd) {
				/* Try and give an error message saying what client failed. */
				DEBUG(0,("read_data: read failure for %d bytes to client %s. Error = %s\n",
					(int)(N - total), client_ip_string, strerror(errno) ));
			} else {
				DEBUG(0,("read_data: read failure for %d. Error = %s\n", (int)(N - total), strerror(errno) ));
			}
			smb_read_error = READ_ERROR;
			return -1;
		}
		total += ret;
	}
	return (ssize_t)total;
}

/****************************************************************************
 Write data to a fd.
****************************************************************************/

ssize_t write_data(int fd, const char *buffer, size_t N)
{
	size_t total=0;
	ssize_t ret;

	while (total < N) {
		ret = sys_write(fd,buffer + total,N - total);

		if (ret == -1) {
			if (fd == client_fd) {
				/* Try and give an error message saying what client failed. */
				DEBUG(0,("write_data: write failure in writing to client %s. Error %s\n",
					client_ip_string, strerror(errno) ));
			} else {
				DEBUG(0,("write_data: write failure. Error = %s\n", strerror(errno) ));
			}
			return -1;
		}

		if (ret == 0) {
			return total;
		}

		total += ret;
	}
	return (ssize_t)total;
}

/****************************************************************************
 Send a keepalive packet (rfc1002).
****************************************************************************/

BOOL send_keepalive(int client)
{
	unsigned char buf[4];

	buf[0] = SMBkeepalive;
	buf[1] = buf[2] = buf[3] = 0;

	return(write_data(client,(char *)buf,4) == 4);
}


/****************************************************************************
 Read 4 bytes of a smb packet and return the smb length of the packet.
 Store the result in the buffer.
 This version of the function will return a length of zero on receiving
 a keepalive packet.
 Timeout is in milliseconds.
****************************************************************************/

static ssize_t read_smb_length_return_keepalive(int fd, char *inbuf, unsigned int timeout)
{
	ssize_t len=0;
	int msg_type;
	BOOL ok = False;

	while (!ok) {
		if (timeout > 0)
			ok = (read_socket_with_timeout(fd,inbuf,4,4,timeout) == 4);
		else 
			ok = (read_data(fd,inbuf,4) == 4);

		if (!ok)
			return(-1);

		len = smb_len(inbuf);
		msg_type = CVAL(inbuf,0);

		if (msg_type == SMBkeepalive) 
			DEBUG(5,("Got keepalive packet\n"));
	}

	DEBUG(10,("got smb length of %lu\n",(unsigned long)len));

	return(len);
}

/****************************************************************************
 Read 4 bytes of a smb packet and return the smb length of the packet.
 Store the result in the buffer. This version of the function will
 never return a session keepalive (length of zero).
 Timeout is in milliseconds.
****************************************************************************/

ssize_t read_smb_length(int fd, char *inbuf, unsigned int timeout)
{
	ssize_t len;

	for(;;) {
		len = read_smb_length_return_keepalive(fd, inbuf, timeout);

		if(len < 0)
			return len;

		/* Ignore session keepalives. */
		if(CVAL(inbuf,0) != SMBkeepalive)
			break;
	}

	DEBUG(10,("read_smb_length: got smb length of %lu\n",
		  (unsigned long)len));

	return len;
}

/****************************************************************************
 Read an smb from a fd. Note that the buffer *MUST* be of size
 BUFFER_SIZE+SAFETY_MARGIN.
 The timeout is in milliseconds. 
 This function will return on receipt of a session keepalive packet.
 Doesn't check the MAC on signed packets.
****************************************************************************/

BOOL receive_smb_raw(int fd, char *buffer, unsigned int timeout)
{
	ssize_t len,ret;

	smb_read_error = 0;

	memset(buffer,'\0',smb_size + 100);

	len = read_smb_length_return_keepalive(fd,buffer,timeout);
	if (len < 0) {
		DEBUG(10,("receive_smb_raw: length < 0!\n"));

		/*
		 * Correct fix. smb_read_error may have already been
		 * set. Only set it here if not already set. Global
		 * variables still suck :-). JRA.
		 */

		if (smb_read_error == 0)
			smb_read_error = READ_ERROR;
		return False;
	}

	/*
	 * A WRITEX with CAP_LARGE_WRITEX can be 64k worth of data plus 65 bytes
	 * of header. Don't print the error if this fits.... JRA.
	 */

	if (len > (BUFFER_SIZE + LARGE_WRITEX_HDR_SIZE)) {
		DEBUG(0,("Invalid packet length! (%lu bytes).\n",(unsigned long)len));
		if (len > BUFFER_SIZE + (SAFETY_MARGIN/2)) {

			/*
			 * Correct fix. smb_read_error may have already been
			 * set. Only set it here if not already set. Global
			 * variables still suck :-). JRA.
			 */

			if (smb_read_error == 0)
				smb_read_error = READ_ERROR;
			return False;
		}
	}

	if(len > 0) {
		if (timeout > 0) {
			ret = read_socket_with_timeout(fd,buffer+4,len,len,timeout);
		} else {
			ret = read_data(fd,buffer+4,len);
		}

		if (ret != len) {
			if (smb_read_error == 0)
				smb_read_error = READ_ERROR;
			return False;
		}
		
		/* not all of samba3 properly checks for packet-termination of strings. This
		   ensures that we don't run off into empty space. */
		SSVAL(buffer+4,len, 0);
	}

	return True;
}

/****************************************************************************
 Wrapper for receive_smb_raw().
 Checks the MAC on signed packets.
****************************************************************************/

BOOL receive_smb(int fd, char *buffer, unsigned int timeout)
{
	if (!receive_smb_raw(fd, buffer, timeout)) {
		return False;
	}

	/* Check the incoming SMB signature. */
	if (!srv_check_sign_mac(buffer, True)) {
		DEBUG(0, ("receive_smb: SMB Signature verification failed on incoming packet!\n"));
		if (smb_read_error == 0)
			smb_read_error = READ_BAD_SIG;
		return False;
	};

	return(True);
}

/****************************************************************************
 Send an smb to a fd.
****************************************************************************/

BOOL send_smb(int fd, char *buffer)
{
	size_t len;
	size_t nwritten=0;
	ssize_t ret;

	/* Sign the outgoing packet if required. */
	srv_calculate_sign_mac(buffer);

	len = smb_len(buffer) + 4;

	while (nwritten < len) {
		ret = write_data(fd,buffer+nwritten,len - nwritten);
		if (ret <= 0) {
			DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
				(int)len,(int)ret, strerror(errno) ));
			return False;
		}
		nwritten += ret;
	}

	return True;
}

/****************************************************************************
 Open a socket of the specified type, port, and address for incoming data.
****************************************************************************/

int open_socket_in( int type, int port, int dlevel, uint32 socket_addr, BOOL rebind )
{
	struct sockaddr_in sock;
	int res;

	memset( (char *)&sock, '\0', sizeof(sock) );

#ifdef HAVE_SOCK_SIN_LEN
	sock.sin_len         = sizeof(sock);
#endif
	sock.sin_port        = htons( port );
	sock.sin_family      = AF_INET;
	sock.sin_addr.s_addr = socket_addr;

	res = socket( AF_INET, type, 0 );
	if( res == -1 ) {
		if( DEBUGLVL(0) ) {
			dbgtext( "open_socket_in(): socket() call failed: " );
			dbgtext( "%s\n", strerror( errno ) );
		}
		return -1;
	}

	/* This block sets/clears the SO_REUSEADDR and possibly SO_REUSEPORT. */
	{
		int val = rebind ? 1 : 0;
		if( setsockopt(res,SOL_SOCKET,SO_REUSEADDR,(char *)&val,sizeof(val)) == -1 ) {
			if( DEBUGLVL( dlevel ) ) {
				dbgtext( "open_socket_in(): setsockopt: " );
				dbgtext( "SO_REUSEADDR = %s ", val?"True":"False" );
				dbgtext( "on port %d failed ", port );
				dbgtext( "with error = %s\n", strerror(errno) );
			}
		}
#ifdef SO_REUSEPORT
		if( setsockopt(res,SOL_SOCKET,SO_REUSEPORT,(char *)&val,sizeof(val)) == -1 ) {
			if( DEBUGLVL( dlevel ) ) {
				dbgtext( "open_socket_in(): setsockopt: ");
				dbgtext( "SO_REUSEPORT = %s ", val?"True":"False" );
				dbgtext( "on port %d failed ", port );
				dbgtext( "with error = %s\n", strerror(errno) );
			}
		}
#endif /* SO_REUSEPORT */
	}

	/* now we've got a socket - we need to bind it */
	if( bind( res, (struct sockaddr *)&sock, sizeof(sock) ) == -1 ) {
		if( DEBUGLVL(dlevel) && (port == SMB_PORT1 || port == SMB_PORT2 || port == NMB_PORT) ) {
			dbgtext( "bind failed on port %d ", port );
			dbgtext( "socket_addr = %s.\n", inet_ntoa( sock.sin_addr ) );
			dbgtext( "Error = %s\n", strerror(errno) );
		}
		close( res ); 
		return( -1 ); 
	}

	DEBUG( 10, ( "bind succeeded on port %d\n", port ) );

	return( res );
 }

/****************************************************************************
 Create an outgoing socket. timeout is in milliseconds.
**************************************************************************/

int open_socket_out(int type, struct in_addr *addr, int port ,int timeout)
{
	struct sockaddr_in sock_out;
	int res,ret;
	int connect_loop = 10;
	int increment = 10;

	/* create a socket to write to */
	res = socket(PF_INET, type, 0);
	if (res == -1) {
                DEBUG(0,("socket error (%s)\n", strerror(errno)));
		return -1;
	}

	if (type != SOCK_STREAM)
		return(res);
  
	memset((char *)&sock_out,'\0',sizeof(sock_out));
	putip((char *)&sock_out.sin_addr,(char *)addr);
  
	sock_out.sin_port = htons( port );
	sock_out.sin_family = PF_INET;

	/* set it non-blocking */
	set_blocking(res,False);

	DEBUG(3,("Connecting to %s at port %d\n",inet_ntoa(*addr),port));
  
	/* and connect it to the destination */
  connect_again:

	ret = connect(res,(struct sockaddr *)&sock_out,sizeof(sock_out));

	/* Some systems return EAGAIN when they mean EINPROGRESS */
	if (ret < 0 && (errno == EINPROGRESS || errno == EALREADY ||
			errno == EAGAIN) && (connect_loop < timeout) ) {
		smb_msleep(connect_loop);
		timeout -= connect_loop;
		connect_loop += increment;
		if (increment < 250) {
			/* After 8 rounds we end up at a max of 255 msec */
			increment *= 1.5;
		}