Apply the changes that Derrell Lipman supplied ...

[Samba/gebeck_regimport.git] / 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 {
        const 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];

        /* wrapped in if statement to prevent streams leak in SCO Openserver 5.0 */
        /* reported on samba-technical  --jerry */
        if ( DEBUGLEVEL >= 5 ) {
        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);
}

/****************************************************************************
 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
****************************************************************************/

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 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 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! (%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;
}

/****************************************************************************
 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)) {
                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_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 = 10;
        int increment = 10;

        /* 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) && (connect_loop < timeout) ) {
                msleep(connect_loop);
                connect_loop += increment;
                if (increment < 250) {
                        /* After 8 rounds we end up at a max of 255 msec */
                        increment *= 1.5;
                }
                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);
}

struct in_addr *client_inaddr(struct sockaddr *sa)
{
        struct sockaddr_in *sockin = (struct sockaddr_in *) (sa);
        int     length = sizeof(*sa);
        
        if (getpeername(client_fd, sa, &length) < 0) {
                DEBUG(0,("getpeername failed. Error was %s\n", strerror(errno) ));
                return NULL;
        }
        
        return &sockin->sin_addr;
}

/*******************************************************************
 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 (!strequal(remotehost, hp->h_name)
            && !strequal(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 unixes 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;
        
        old_umask = umask(0);
        
        /* 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)));
                                goto out_umask;
                        }
                } else {
                        DEBUG(0, ("lstat failed on socket directory %s: %s\n",
                                socket_dir, strerror(errno)));
                        goto out_umask;
                }
        } 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));
                        goto out_umask;
                }
                if ((st.st_uid != sec_initial_uid()) || 
                                ((st.st_mode & 0777) != dir_perms)) {
                        DEBUG(0, ("invalid permissions on socket directory "
                                "%s\n", socket_dir));
                        goto out_umask;
                }
        }
        
        /* Create the socket file */
        
        sock = socket(AF_UNIX, SOCK_STREAM, 0);
        
        if (sock == -1) {
                perror("socket");
                goto out_umask;
        }
        
        pstr_sprintf(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)));
                goto out_close;
        }
        
        if (listen(sock, 5) == -1) {
                DEBUG(0, ("listen failed on pipe socket %s: %s\n", path,
                        strerror(errno)));
                goto out_close;
        }
        
        umask(old_umask);
        return sock;

out_close:
        close(sock);

out_umask:
        umask(old_umask);
        return -1;

#else
        DEBUG(0, ("create_pipe_sock: No Unix sockets on this system\n"));
        return -1;
#endif /* HAVE_UNIXSOCKET */
}