samba-mirror/source3/lib/util_sock.c

/* 
   Unix SMB/CIFS implementation.
   Samba utility functions
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Tim Potter      2000-2001
   
   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.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

/* the last IP received from */
struct in_addr lastip;

/* the last port received from */
int lastport=0;

int smb_read_error = 0;

/****************************************************************************
 Determine if a file descriptor is in fact a socket.
****************************************************************************/

BOOL is_a_socket(int fd)
{
	int v,l;
	l = sizeof(int);
	return(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0);
}

enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};

typedef struct smb_socket_option {
	char *name;
	int level;
	int option;
	int value;
	int opttype;
} smb_socket_option;

static const smb_socket_option socket_options[] = {
  {"SO_KEEPALIVE",      SOL_SOCKET,    SO_KEEPALIVE,    0,                 OPT_BOOL},
  {"SO_REUSEADDR",      SOL_SOCKET,    SO_REUSEADDR,    0,                 OPT_BOOL},
  {"SO_BROADCAST",      SOL_SOCKET,    SO_BROADCAST,    0,                 OPT_BOOL},
#ifdef TCP_NODELAY
  {"TCP_NODELAY",       IPPROTO_TCP,   TCP_NODELAY,     0,                 OPT_BOOL},
#endif
#ifdef IPTOS_LOWDELAY
  {"IPTOS_LOWDELAY",    IPPROTO_IP,    IP_TOS,          IPTOS_LOWDELAY,    OPT_ON},
#endif
#ifdef IPTOS_THROUGHPUT
  {"IPTOS_THROUGHPUT",  IPPROTO_IP,    IP_TOS,          IPTOS_THROUGHPUT,  OPT_ON},
#endif
#ifdef SO_REUSEPORT
  {"SO_REUSEPORT",      SOL_SOCKET,    SO_REUSEPORT,    0,                 OPT_BOOL},
#endif
#ifdef SO_SNDBUF
  {"SO_SNDBUF",         SOL_SOCKET,    SO_SNDBUF,       0,                 OPT_INT},
#endif
#ifdef SO_RCVBUF
  {"SO_RCVBUF",         SOL_SOCKET,    SO_RCVBUF,       0,                 OPT_INT},
#endif
#ifdef SO_SNDLOWAT
  {"SO_SNDLOWAT",       SOL_SOCKET,    SO_SNDLOWAT,     0,                 OPT_INT},
#endif
#ifdef SO_RCVLOWAT
  {"SO_RCVLOWAT",       SOL_SOCKET,    SO_RCVLOWAT,     0,                 OPT_INT},
#endif
#ifdef SO_SNDTIMEO
  {"SO_SNDTIMEO",       SOL_SOCKET,    SO_SNDTIMEO,     0,                 OPT_INT},
#endif
#ifdef SO_RCVTIMEO
  {"SO_RCVTIMEO",       SOL_SOCKET,    SO_RCVTIMEO,     0,                 OPT_INT},
#endif
  {NULL,0,0,0,0}};

/****************************************************************************
 Print socket options.
****************************************************************************/

static void print_socket_options(int s)
{
	int value, vlen = 4;
	const smb_socket_option *p = &socket_options[0];

	for (; p->name != NULL; p++) {
		if (getsockopt(s, p->level, p->option, (void *)&value, &vlen) == -1) {
			DEBUG(5,("Could not test socket option %s.\n", p->name));
		} else {
			DEBUG(5,("socket option %s = %d\n",p->name,value));
		}
	}
 }

/****************************************************************************
 Set user socket options.
****************************************************************************/

void set_socket_options(int fd, const char *options)
{
	fstring tok;

	while (next_token(&options,tok," \t,", sizeof(tok))) {
		int ret=0,i;
		int value = 1;
		char *p;
		BOOL got_value = False;

		if ((p = strchr_m(tok,'='))) {
			*p = 0;
			value = atoi(p+1);
			got_value = True;
		}

		for (i=0;socket_options[i].name;i++)
			if (strequal(socket_options[i].name,tok))
				break;

		if (!socket_options[i].name) {
			DEBUG(0,("Unknown socket option %s\n",tok));
			continue;
		}

		switch (socket_options[i].opttype) {
		case OPT_BOOL:
		case OPT_INT:
			ret = setsockopt(fd,socket_options[i].level,
						socket_options[i].option,(char *)&value,sizeof(int));
			break;

		case OPT_ON:
			if (got_value)
				DEBUG(0,("syntax error - %s does not take a value\n",tok));

			{
				int on = socket_options[i].value;
				ret = setsockopt(fd,socket_options[i].level,
							socket_options[i].option,(char *)&on,sizeof(int));
			}
			break;	  
		}
      
		if (ret != 0)
			DEBUG(0,("Failed to set socket option %s (Error %s)\n",tok, strerror(errno) ));
	}

	print_socket_options(fd);
}

/****************************************************************************
 Read from a socket.
****************************************************************************/

ssize_t read_udp_socket(int fd,char *buf,size_t len)
{
	ssize_t ret;
	struct sockaddr_in sock;
	socklen_t socklen = sizeof(sock);

	memset((char *)&sock,'\0',socklen);
	memset((char *)&lastip,'\0',sizeof(lastip));
	ret = (ssize_t)sys_recvfrom(fd,buf,len,0,(struct sockaddr *)&sock,&socklen);
	if (ret <= 0) {
		DEBUG(2,("read socket failed. ERRNO=%s\n",strerror(errno)));
		return(0);
	}

	lastip = sock.sin_addr;
	lastport = ntohs(sock.sin_port);

	DEBUG(10,("read_udp_socket: lastip %s lastport %d read: %d\n",
			inet_ntoa(lastip), lastport, ret));

	return(ret);
}

/*******************************************************************
 checks if read data is outstanding.
 ********************************************************************/
static int read_data_outstanding(int fd, unsigned int time_out)
{
	int selrtn;
	fd_set fds;
	struct timeval timeout;

	FD_ZERO(&fds);
	FD_SET(fd, &fds);

	timeout.tv_sec = (time_t) (time_out / 1000);
	timeout.tv_usec = (long)(1000 * (time_out % 1000));

	selrtn = sys_select_intr(fd + 1, &fds, NULL, NULL, &timeout);

	if (selrtn <= 0)
	{
		return selrtn;
	}
	return FD_ISSET(fd, &fds) ? 1 : 0;
}

/****************************************************************************
 Read data from a socket with a timout in msec.
 mincount = if timeout, minimum to read before returning
 maxcount = number to be read.
 time_out = timeout in milliseconds
****************************************************************************/

static ssize_t read_socket_with_timeout(int fd,char *buf,size_t mincnt,size_t maxcnt,unsigned int time_out)
{
	fd_set fds;
	int selrtn;
	ssize_t readret;
	size_t nread = 0;
	struct timeval timeout;
	
	/* just checking .... */
	if (maxcnt <= 0)
		return(0);
	
	smb_read_error = 0;
	
	/* Blocking read */
	if (time_out <= 0) {
		if (mincnt == 0) mincnt = maxcnt;
		
		while (nread < mincnt) {
			readret = sys_read(fd, buf + nread, maxcnt - nread);
			
			if (readret == 0) {
				DEBUG(5,("read_socket_with_timeout: blocking read. EOF from client.\n"));
				smb_read_error = READ_EOF;
				return -1;
			}
			
			if (readret == -1) {
				DEBUG(0,("read_socket_with_timeout: read error = %s.\n", strerror(errno) ));
				smb_read_error = READ_ERROR;
				return -1;
			}
			nread += readret;
		}
		return((ssize_t)nread);
	}
	
	/* Most difficult - timeout read */
	/* If this is ever called on a disk file and 
	   mincnt is greater then the filesize then
	   system performance will suffer severely as 
	   select always returns true on disk files */
	
	/* 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? */
			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 */
			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 a fd with a timout in msec.
 mincount = if timeout, minimum to read before returning
 maxcount = number to be read.
 time_out = timeout in milliseconds
****************************************************************************/

ssize_t read_with_timeout(int fd, char *buf, size_t mincnt, size_t maxcnt,
			  unsigned int time_out)
{
	ssize_t readret;
	size_t nread = 0;
	
	/* just checking .... */
	if (maxcnt <= 0)
		return(0);
	
	/* Blocking read */
	if (time_out <= 0) {
		if (mincnt == 0) mincnt = maxcnt;
		
		while (nread < mincnt) {
			readret = sys_read(fd, buf + nread, maxcnt - nread);
			
			if (readret <= 0)
				return readret;
			
			nread += readret;
		}
		return((ssize_t)nread);
	}
	
	/* Most difficult - timeout read */
	/* If this is ever called on a disk file and 
	   mincnt is greater then the filesize then
	   system performance will suffer severely as 
	   select always returns true on disk files */
	
	for (nread=0; nread < mincnt; ) {      
		int selrtn = read_data_outstanding(fd, time_out);
		
		if(selrtn <= 0)
			return selrtn;
		
		readret = sys_read(fd, buf+nread, maxcnt-nread);
		
		if (readret <= 0)
			return readret;
		
		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) {
			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;
}

/****************************************************************************
 Read data from a socket, reading exactly N bytes. 
****************************************************************************/

static ssize_t read_socket_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_socket_data: recv of %d returned 0. Error = %s\n", (int)(N - total), strerror(errno) ));
			smb_read_error = READ_EOF;
			return 0;
		}

		if (ret == -1) {
			DEBUG(0,("read_socket_data: recv 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,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) {
			DEBUG(0,("write_data: write failure. Error = %s\n", strerror(errno) ));
			return -1;
		}
		if (ret == 0)
			return total;

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

/****************************************************************************
 Write data to a socket - use send rather than write.
****************************************************************************/

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

	while (total < N) {
		ret = sys_send(fd,buffer + total,N - total,0);

		if (ret == -1) {
			DEBUG(0,("write_socket_data: write failure. Error = %s\n", strerror(errno) ));
			return -1;
		}
		if (ret == 0)
			return total;

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

/****************************************************************************
write to a socket
****************************************************************************/

ssize_t write_socket(int fd,char *buf,size_t len)
{
	ssize_t ret=0;

	DEBUG(6,("write_socket(%d,%d)\n",fd,(int)len));
	ret = write_socket_data(fd,buf,len);
      
	DEBUG(6,("write_socket(%d,%d) wrote %d\n",fd,(int)len,(int)ret));
	if(ret <= 0)
		DEBUG(0,("write_socket: Error writing %d bytes to socket %d: ERRNO = %s\n", 
			(int)len, fd, strerror(errno) ));

	return(ret);
}

/****************************************************************************
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_socket_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_socket_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 %d\n",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 %d\n",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 a
  receipt of a session keepalive packet.
****************************************************************************/

BOOL receive_smb(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: 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! (%d bytes).\n",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) {
		ret = read_socket_data(fd,buffer+4,len);
		if (ret != len) {
			if (smb_read_error == 0)
				smb_read_error = READ_ERROR;
			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;
	len = smb_len(buffer) + 4;

	while (nwritten < len) {
		ret = write_socket(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 = 250; /* 250 milliseconds */
  int loops = (timeout) / connect_loop;

  /* create a socket to write to */
  res = socket(PF_INET, type, 0);
  if (res == -1) 
    { DEBUG(0,("socket error\n")); 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) && loops--) {
    msleep(connect_loop);
    goto connect_again;
  }

  if (ret < 0 && (errno == EINPROGRESS || errno == EALREADY ||
         errno == EAGAIN)) {
      DEBUG(1,("timeout connecting to %s:%d\n",inet_ntoa(*addr),port));
      close(res);
      return -1;
  }

#ifdef EISCONN
  if (ret < 0 && errno == EISCONN) {
    errno = 0;
    ret = 0;
  }
#endif

  if (ret < 0) {
    DEBUG(2,("error connecting to %s:%d (%s)\n",
	     inet_ntoa(*addr),port,strerror(errno)));
    close(res);
    return -1;
  }

  /* set it blocking again */
  set_blocking(res,True);

  return res;
}

/*
  open a connected UDP socket to host on port
*/
int open_udp_socket(const char *host, int port)
{
	int type = SOCK_DGRAM;
	struct sockaddr_in sock_out;
	int res;
	struct in_addr *addr;

	addr = interpret_addr2(host);

	res = socket(PF_INET, type, 0);
	if (res == -1) {
		return -1;
	}

	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;

	if (connect(res,(struct sockaddr *)&sock_out,sizeof(sock_out))) {
		close(res);
		return -1;
	}

	return res;
}


/* the following 3 client_*() functions are nasty ways of allowing
   some generic functions to get info that really should be hidden in
   particular modules */
static int client_fd = -1;

void client_setfd(int fd)
{
	client_fd = fd;
}

char *client_name(void)
{
	return get_socket_name(client_fd,False);
}

char *client_addr(void)
{
	return get_socket_addr(client_fd);
}

/*******************************************************************
 matchname - determine if host name matches IP address. Used to
 confirm a hostname lookup to prevent spoof attacks
 ******************************************************************/
static BOOL matchname(char *remotehost,struct in_addr  addr)
{
	struct hostent *hp;
	int     i;
	
	if ((hp = sys_gethostbyname(remotehost)) == 0) {
		DEBUG(0,("sys_gethostbyname(%s): lookup failure.\n", remotehost));
		return False;
	} 

	/*
	 * Make sure that gethostbyname() returns the "correct" host name.
	 * Unfortunately, gethostbyname("localhost") sometimes yields
	 * "localhost.domain". Since the latter host name comes from the
	 * local DNS, we just have to trust it (all bets are off if the local
	 * DNS is perverted). We always check the address list, though.
	 */
	
	if (strcasecmp(remotehost, hp->h_name)
	    && strcasecmp(remotehost, "localhost")) {
		DEBUG(0,("host name/name mismatch: %s != %s\n",
			 remotehost, hp->h_name));
		return False;
	}
	
	/* Look up the host address in the address list we just got. */
	for (i = 0; hp->h_addr_list[i]; i++) {
		if (memcmp(hp->h_addr_list[i], (char *) & addr, sizeof(addr)) == 0)
			return True;
	}
	
	/*
	 * The host name does not map to the original host address. Perhaps
	 * someone has compromised a name server. More likely someone botched
	 * it, but that could be dangerous, too.
	 */
	
	DEBUG(0,("host name/address mismatch: %s != %s\n",
		 inet_ntoa(addr), hp->h_name));
	return False;
}

 
/*******************************************************************
 return the DNS name of the remote end of a socket
 ******************************************************************/
char *get_socket_name(int fd, BOOL force_lookup)
{
	static pstring name_buf;
	static fstring addr_buf;
	struct hostent *hp;
	struct in_addr addr;
	char *p;

	/* reverse lookups can be *very* expensive, and in many
	   situations won't work because many networks don't link dhcp
	   with dns. To avoid the delay we avoid the lookup if
	   possible */
	if (!lp_hostname_lookups() && (force_lookup == False)) {
		return get_socket_addr(fd);
	}
	
	p = get_socket_addr(fd);

	/* it might be the same as the last one - save some DNS work */
	if (strcmp(p, addr_buf) == 0) return name_buf;

	pstrcpy(name_buf,"UNKNOWN");
	if (fd == -1) return name_buf;

	fstrcpy(addr_buf, p);

	addr = *interpret_addr2(p);
	
	/* Look up the remote host name. */
	if ((hp = gethostbyaddr((char *)&addr.s_addr, sizeof(addr.s_addr), AF_INET)) == 0) {
		DEBUG(1,("Gethostbyaddr failed for %s\n",p));
		pstrcpy(name_buf, p);
	} else {
		pstrcpy(name_buf,(char *)hp->h_name);
		if (!matchname(name_buf, addr)) {
			DEBUG(0,("Matchname failed on %s %s\n",name_buf,p));
			pstrcpy(name_buf,"UNKNOWN");
		}
	}

	alpha_strcpy(name_buf, name_buf, "_-.", sizeof(name_buf));
	if (strstr(name_buf,"..")) {
		pstrcpy(name_buf, "UNKNOWN");
	}

	return name_buf;
}

/*******************************************************************
 return the IP addr of the remote end of a socket as a string 
 ******************************************************************/
char *get_socket_addr(int fd)
{
	struct sockaddr sa;
	struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
	int     length = sizeof(sa);
	static fstring addr_buf;

	fstrcpy(addr_buf,"0.0.0.0");

	if (fd == -1) {
		return addr_buf;
	}
	
	if (getpeername(fd, &sa, &length) < 0) {
		DEBUG(0,("getpeername failed. Error was %s\n", strerror(errno) ));
		return addr_buf;
	}
	
	fstrcpy(addr_buf,(char *)inet_ntoa(sockin->sin_addr));
	
	return addr_buf;
}


/*******************************************************************
 Create protected unix domain socket.

 some unixen cannot set permissions on a ux-dom-sock, so we
 have to make sure that the directory contains the protection
 permissions, instead.
 ******************************************************************/
int create_pipe_sock(const char *socket_dir,
		     const char *socket_name,
		     mode_t dir_perms)
{
#ifdef HAVE_UNIXSOCKET
        struct sockaddr_un sunaddr;
        struct stat st;
        int sock;
        mode_t old_umask;
        pstring path;
        
        /* Create the socket directory or reuse the existing one */
        
        if (lstat(socket_dir, &st) == -1) {
                
                if (errno == ENOENT) {
                        
                        /* Create directory */
                        
                        if (mkdir(socket_dir, dir_perms) == -1) {
                                DEBUG(0, ("error creating socket directory "
                                          "%s: %s\n", socket_dir, 
                                          strerror(errno)));
                                return -1;
                        }
                        
                } else {
                        
                        DEBUG(0, ("lstat failed on socket directory %s: %s\n",
                                  socket_dir, strerror(errno)));
                        return -1;
                }
                
        } else {
                
                /* Check ownership and permission on existing directory */
                
                if (!S_ISDIR(st.st_mode)) {
                        DEBUG(0, ("socket directory %s isn't a directory\n",
                                  socket_dir));
                        return -1;
                }
                
                if ((st.st_uid != sec_initial_uid()) || 
                    ((st.st_mode & 0777) != dir_perms)) {
                        DEBUG(0, ("invalid permissions on socket directory "
                                  "%s\n", socket_dir));
                        return -1;
                }
        }
        
        /* Create the socket file */
        
        old_umask = umask(0);
        
        sock = socket(AF_UNIX, SOCK_STREAM, 0);
        
        if (sock == -1) {
                perror("socket");
		umask(old_umask);
                return -1;
        }
        
        snprintf(path, sizeof(path), "%s/%s", socket_dir, socket_name);
        
        unlink(path);
        memset(&sunaddr, 0, sizeof(sunaddr));
        sunaddr.sun_family = AF_UNIX;
        safe_strcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)-1);
        
        if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
                DEBUG(0, ("bind failed on pipe socket %s: %s\n",
                          path,
                          strerror(errno)));
                close(sock);
		umask(old_umask);
                return -1;
        }
        
        if (listen(sock, 5) == -1) {
                DEBUG(0, ("listen failed on pipe socket %s: %s\n",
                          path,
                          strerror(errno)));
                close(sock);
		umask(old_umask);
                return -1;
        }
        
        umask(old_umask);
        
        /* Success! */
        
        return sock;
#else
        DEBUG(0, ("create_pipe_sock: No Unix sockets on this system\n"));
        return -1;
#endif /* HAVE_UNIXSOCKET */
}

/*******************************************************************
this is like socketpair but uses tcp. It is used by the Samba
regression test code
The function guarantees that nobody else can attach to the socket,
or if they do that this function fails and the socket gets closed
returns 0 on success, -1 on failure
the resulting file descriptors are symmetrical
 ******************************************************************/
static int socketpair_tcp(int fd[2])
{
	int listener;
	struct sockaddr_in sock;
	struct sockaddr_in sock2;
	socklen_t socklen = sizeof(sock);
	int connect_done = 0;
	
	fd[0] = fd[1] = listener = -1;

	memset(&sock, 0, sizeof(sock));
	
	if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1) goto failed;

        memset(&sock2, 0, sizeof(sock2));
#ifdef HAVE_SOCK_SIN_LEN
        sock2.sin_len = sizeof(sock2);
#endif
        sock2.sin_family = PF_INET;

        bind(listener, (struct sockaddr *)&sock2, sizeof(sock2));

	if (listen(listener, 1) != 0) goto failed;

	if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0) goto failed;

	if ((fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1) goto failed;

	set_blocking(fd[1], 0);

	sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

	if (connect(fd[1],(struct sockaddr *)&sock,sizeof(sock)) == -1) {
		if (errno != EINPROGRESS) goto failed;
	} else {
		connect_done = 1;
	}

	if ((fd[0] = accept(listener, (struct sockaddr *)&sock, &socklen)) == -1) goto failed;

	close(listener);
	if (connect_done == 0) {
		if (connect(fd[1],(struct sockaddr *)&sock,sizeof(sock)) != 0
		    && errno != EISCONN) goto failed;
	}

	set_blocking(fd[1], 1);

	/* all OK! */
	return 0;

 failed:
	if (fd[0] != -1) close(fd[0]);
	if (fd[1] != -1) close(fd[1]);
	if (listener != -1) close(listener);
	return -1;
}


/*******************************************************************
run a program on a local tcp socket, this is used to launch smbd
when regression testing
the return value is a socket which is attached to a subprocess
running "prog". stdin and stdout are attached. stderr is left
attached to the original stderr
 ******************************************************************/
int sock_exec(const char *prog)
{
	int fd[2];
	if (socketpair_tcp(fd) != 0) {
		DEBUG(0,("socketpair_tcp failed (%s)\n", strerror(errno)));
		return -1;
	}
	if (fork() == 0) {
		close(fd[0]);
		close(0);
		close(1);
		dup(fd[1]);
		dup(fd[1]);
		exit(system(prog));
	}
	close(fd[1]);
	return fd[0];
}