nmblib.c

MC Linux/Unix 终端下文件管理器

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   NBT netbios library routines
   Copyright (C) Andrew Tridgell 1994-1998
   
   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"

extern int DEBUGLEVEL;

int num_good_sends = 0;
int num_good_receives = 0;

static struct opcode_names {
	char *nmb_opcode_name;
	int opcode;
} const nmb_header_opcode_names[] = {
      {"Query",           0 },
      {"Registration",      5 },
      {"Release",           6 },
      {"WACK",              7 },
      {"Refresh",           8 },
      {"Refresh(altcode)",  9 },
      {"Multi-homed Registration", 15 },
      {0, -1 }
};

/****************************************************************************
 * Lookup a nmb opcode name.
 ****************************************************************************/
static char *lookup_opcode_name( int opcode )
{
  const struct opcode_names *op_namep = nmb_header_opcode_names;

  while(op_namep->nmb_opcode_name) {
    if(opcode == op_namep->opcode)
      return op_namep->nmb_opcode_name;
    op_namep++;
  }
  return "<unknown opcode>";
}

/****************************************************************************
  print out a res_rec structure
  ****************************************************************************/
static void debug_nmb_res_rec(struct res_rec *res, char *hdr)
{
  int i, j;

  DEBUGADD( 4, ( "    %s: nmb_name=%s rr_type=%d rr_class=%d ttl=%d\n",
                 hdr,
                 nmb_namestr(&res->rr_name),
                 res->rr_type,
                 res->rr_class,
                 res->ttl ) );

  if( res->rdlength == 0 || res->rdata == NULL )
    return;

  for (i = 0; i < res->rdlength; i+= 16)
    {
      DEBUGADD(4, ("    %s %3x char ", hdr, i));

      for (j = 0; j < 16; j++)
	{
	  unsigned char x = res->rdata[i+j];
	  if (x < 32 || x > 127) x = '.';
	  
	  if (i+j >= res->rdlength) break;
	  DEBUGADD(4, ("%c", x));
	}
      
      DEBUGADD(4, ("   hex "));

      for (j = 0; j < 16; j++)
	{
	  if (i+j >= res->rdlength) break;
	  DEBUGADD(4, ("%02X", (unsigned char)res->rdata[i+j]));
	}
      
      DEBUGADD(4, ("\n"));
    }
}

/****************************************************************************
  process a nmb packet
  ****************************************************************************/
void debug_nmb_packet(struct packet_struct *p)
{
  struct nmb_packet *nmb = &p->packet.nmb;

  if( DEBUGLVL( 4 ) )
    {
    dbgtext( "nmb packet from %s(%d) header: id=%d opcode=%s(%d) response=%s\n",
             inet_ntoa(p->ip), p->port,
             nmb->header.name_trn_id,
             lookup_opcode_name(nmb->header.opcode),
             nmb->header.opcode,
             BOOLSTR(nmb->header.response) );
    dbgtext( "    header: flags: bcast=%s rec_avail=%s rec_des=%s trunc=%s auth=%s\n",
             BOOLSTR(nmb->header.nm_flags.bcast),
             BOOLSTR(nmb->header.nm_flags.recursion_available),
             BOOLSTR(nmb->header.nm_flags.recursion_desired),
             BOOLSTR(nmb->header.nm_flags.trunc),
             BOOLSTR(nmb->header.nm_flags.authoritative) );
    dbgtext( "    header: rcode=%d qdcount=%d ancount=%d nscount=%d arcount=%d\n",
             nmb->header.rcode,
             nmb->header.qdcount,
             nmb->header.ancount,
             nmb->header.nscount,
             nmb->header.arcount );
    }

  if (nmb->header.qdcount)
    {
      DEBUGADD( 4, ( "    question: q_name=%s q_type=%d q_class=%d\n",
                     nmb_namestr(&nmb->question.question_name),
                     nmb->question.question_type,
                     nmb->question.question_class) );
    }

  if (nmb->answers && nmb->header.ancount)
    {
      debug_nmb_res_rec(nmb->answers,"answers");
    }
  if (nmb->nsrecs && nmb->header.nscount)
    {
      debug_nmb_res_rec(nmb->nsrecs,"nsrecs");
    }
  if (nmb->additional && nmb->header.arcount)
    {
      debug_nmb_res_rec(nmb->additional,"additional");
    }
}

/*******************************************************************
  handle "compressed" name pointers
  ******************************************************************/
static BOOL handle_name_ptrs(unsigned char *ubuf,int *offset,int length,
			     BOOL *got_pointer,int *ret)
{
  int loop_count=0;
  
  while ((ubuf[*offset] & 0xC0) == 0xC0) {
    if (!*got_pointer) (*ret) += 2;
    (*got_pointer)=True;
    (*offset) = ((ubuf[*offset] & ~0xC0)<<8) | ubuf[(*offset)+1];
    if (loop_count++ == 10 || (*offset) < 0 || (*offset)>(length-2)) {
      return(False);
    }
  }
  return(True);
}

/*******************************************************************
  parse a nmb name from "compressed" format to something readable
  return the space taken by the name, or 0 if the name is invalid
  ******************************************************************/
static int parse_nmb_name(char *inbuf,int offset,int length, struct nmb_name *name)
{
  int m,n=0;
  unsigned char *ubuf = (unsigned char *)inbuf;
  int ret = 0;
  BOOL got_pointer=False;

  if (length - offset < 2)
    return(0);  

  /* handle initial name pointers */
  if (!handle_name_ptrs(ubuf,&offset,length,&got_pointer,&ret))
    return(0);
  
  m = ubuf[offset];

  if (!m)
    return(0);
  if ((m & 0xC0) || offset+m+2 > length)
    return(0);

  memset((char *)name,'\0',sizeof(*name));

  /* the "compressed" part */
  if (!got_pointer)
    ret += m + 2;
  offset++;
  while (m > 0) {
    unsigned char c1,c2;
    c1 = ubuf[offset++]-'A';
    c2 = ubuf[offset++]-'A';
    if ((c1 & 0xF0) || (c2 & 0xF0) || (n > sizeof(name->name)-1))
      return(0);
    name->name[n++] = (c1<<4) | c2;
    m -= 2;
  }
  name->name[n] = 0;

  if (n==16) {
    /* parse out the name type, 
       its always in the 16th byte of the name */
    name->name_type = ((unsigned char)name->name[15]) & 0xff;
  
    /* remove trailing spaces */
    name->name[15] = 0;
    n = 14;
    while (n && name->name[n]==' ')
      name->name[n--] = 0;  
  }

  /* now the domain parts (if any) */
  n = 0;
  while (ubuf[offset]) {
    /* we can have pointers within the domain part as well */
    if (!handle_name_ptrs(ubuf,&offset,length,&got_pointer,&ret))
      return(0);

    m = ubuf[offset];
    if (!got_pointer)
      ret += m+1;
    if (n)
      name->scope[n++] = '.';
    if (m+2+offset>length || n+m+1>sizeof(name->scope))
      return(0);
    offset++;
    while (m--)
      name->scope[n++] = (char)ubuf[offset++];
  }
  name->scope[n++] = 0;  

  return(ret);
}


/*******************************************************************
  put a compressed nmb name into a buffer. return the length of the
  compressed name

  compressed names are really weird. The "compression" doubles the
  size. The idea is that it also means that compressed names conform
  to the doman name system. See RFC1002.
  ******************************************************************/
static int put_nmb_name(char *buf,int offset,struct nmb_name *name)
{
  int ret,m;
  fstring buf1;
  char *p;

  if (strcmp(name->name,"*") == 0) {
    /* special case for wildcard name */
    memset(buf1,'\0',20);
    buf1[0] = '*';
    buf1[15] = name->name_type;
  } else {
    slprintf(buf1, sizeof(buf1) - 1,"%-15.15s%c",name->name,name->name_type);
  }

  buf[offset] = 0x20;

  ret = 34;

  for (m=0;m<16;m++) {
    buf[offset+1+2*m] = 'A' + ((buf1[m]>>4)&0xF);
    buf[offset+2+2*m] = 'A' + (buf1[m]&0xF);
  }
  offset += 33;

  buf[offset] = 0;

  if (name->scope[0]) {
    /* XXXX this scope handling needs testing */
    ret += strlen(name->scope) + 1;
    pstrcpy(&buf[offset+1],name->scope);  
  
    p = &buf[offset+1];
    while ((p = strchr(p,'.'))) {
      buf[offset] = PTR_DIFF(p,&buf[offset+1]);
      offset += (buf[offset] + 1);
      p = &buf[offset+1];
    }
    buf[offset] = strlen(&buf[offset+1]);
  }

  return(ret);
}

/*******************************************************************
  useful for debugging messages
  ******************************************************************/
char *nmb_namestr(struct nmb_name *n)
{
  static int i=0;
  static fstring ret[4];
  char *p = ret[i];

  if (!n->scope[0])
    slprintf(p,sizeof(fstring)-1, "%s<%02x>",n->name,n->name_type);
  else
    slprintf(p,sizeof(fstring)-1, "%s<%02x>.%s",n->name,n->name_type,n->scope);

  i = (i+1)%4;
  return(p);
}

/*******************************************************************
  allocate and parse some resource records
  ******************************************************************/
static BOOL parse_alloc_res_rec(char *inbuf,int *offset,int length,
				struct res_rec **recs, int count)
{
  int i;
  *recs = (struct res_rec *)malloc(sizeof(**recs)*count);
  if (!*recs) return(False);

  memset((char *)*recs,'\0',sizeof(**recs)*count);

  for (i=0;i<count;i++) {
    int l = parse_nmb_name(inbuf,*offset,length,&(*recs)[i].rr_name);
    (*offset) += l;
    if (!l || (*offset)+10 > length) {
      free(*recs);
      return(False);
    }
    (*recs)[i].rr_type = RSVAL(inbuf,(*offset));
    (*recs)[i].rr_class = RSVAL(inbuf,(*offset)+2);
    (*recs)[i].ttl = RIVAL(inbuf,(*offset)+4);
    (*recs)[i].rdlength = RSVAL(inbuf,(*offset)+8);
    (*offset) += 10;
    if ((*recs)[i].rdlength>sizeof((*recs)[i].rdata) || 
	(*offset)+(*recs)[i].rdlength > length) {
      free(*recs);
      return(False);
    }
    memcpy((*recs)[i].rdata,inbuf+(*offset),(*recs)[i].rdlength);
    (*offset) += (*recs)[i].rdlength;    
  }
  return(True);
}

/*******************************************************************
  put a resource record into a packet
  ******************************************************************/
static int put_res_rec(char *buf,int offset,struct res_rec *recs,int count)
{
  int ret=0;
  int i;

  for (i=0;i<count;i++) {
    int l = put_nmb_name(buf,offset,&recs[i].rr_name);
    offset += l;
    ret += l;
    RSSVAL(buf,offset,recs[i].rr_type);
    RSSVAL(buf,offset+2,recs[i].rr_class);
    RSIVAL(buf,offset+4,recs[i].ttl);
    RSSVAL(buf,offset+8,recs[i].rdlength);
    memcpy(buf+offset+10,recs[i].rdata,recs[i].rdlength);
    offset += 10+recs[i].rdlength;
    ret += 10+recs[i].rdlength;
  }

  return(ret);
}

/*******************************************************************
  put a compressed name pointer record into a packet
  ******************************************************************/
static int put_compressed_name_ptr(unsigned char *buf,int offset,struct res_rec *rec,int ptr_offset)
{  
  int ret=0;
  buf[offset] = (0xC0 | ((ptr_offset >> 8) & 0xFF));
  buf[offset+1] = (ptr_offset & 0xFF);
  offset += 2;
  ret += 2;
  RSSVAL(buf,offset,rec->rr_type);
  RSSVAL(buf,offset+2,rec->rr_class);
  RSIVAL(buf,offset+4,rec->ttl);
  RSSVAL(buf,offset+8,rec->rdlength);
  memcpy(buf+offset+10,rec->rdata,rec->rdlength);
  offset += 10+rec->rdlength;
  ret += 10+rec->rdlength;
    
  return(ret);
}

/*******************************************************************
  parse a dgram packet. Return False if the packet can't be parsed 
  or is invalid for some reason, True otherwise 

  this is documented in section 4.4.1 of RFC1002
  ******************************************************************/
static BOOL parse_dgram(char *inbuf,int length,struct dgram_packet *dgram)
{
  int offset;
  int flags;

  memset((char *)dgram,'\0',sizeof(*dgram));

  if (length < 14) return(False);

  dgram->header.msg_type = CVAL(inbuf,0);
  flags = CVAL(inbuf,1);
  dgram->header.flags.node_type = (enum node_type)((flags>>2)&3);
  if (flags & 1) dgram->header.flags.more = True;
  if (flags & 2) dgram->header.flags.first = True;
  dgram->header.dgm_id = RSVAL(inbuf,2);
  putip((char *)&dgram->header.source_ip,inbuf+4);
  dgram->header.source_port = RSVAL(inbuf,8);
  dgram->header.dgm_length = RSVAL(inbuf,10);
  dgram->header.packet_offset = RSVAL(inbuf,12);

  offset = 14;

  if (dgram->header.msg_type == 0x10 ||
      dgram->header.msg_type == 0x11 ||
      dgram->header.msg_type == 0x12) {      
    offset += parse_nmb_name(inbuf,offset,length,&dgram->source_name);
    offset += parse_nmb_name(inbuf,offset,length,&dgram->dest_name);
  }

  if (offset >= length || (length-offset > sizeof(dgram->data))) 
    return(False);

  dgram->datasize = length-offset;
  memcpy(dgram->data,inbuf+offset,dgram->datasize);

  return(True);
}


/*******************************************************************
  parse a nmb packet. Return False if the packet can't be parsed 
  or is invalid for some reason, True otherwise 
  ******************************************************************/
static BOOL parse_nmb(char *inbuf,int length,struct nmb_packet *nmb)
{
  int nm_flags,offset;

  memset((char *)nmb,'\0',sizeof(*nmb));

  if (length < 12) return(False);

  /* parse the header */
  nmb->header.name_trn_id = RSVAL(inbuf,0);

  DEBUG(10,("parse_nmb: packet id = %d\n", nmb->header.name_trn_id));

  nmb->header.opcode = (CVAL(inbuf,2) >> 3) & 0xF;
  nmb->header.response = ((CVAL(inbuf,2)>>7)&1)?True:False;
  nm_flags = ((CVAL(inbuf,2) & 0x7) << 4) + (CVAL(inbuf,3)>>4);
  nmb->header.nm_flags.bcast = (nm_flags&1)?True:False;
  nmb->header.nm_flags.recursion_available = (nm_flags&8)?True:False;
  nmb->header.nm_flags.recursion_desired = (nm_flags&0x10)?True:False;
  nmb->header.nm_flags.trunc = (nm_flags&0x20)?True:False;
  nmb->header.nm_flags.authoritative = (nm_flags&0x40)?True:False;  
  nmb->header.rcode = CVAL(inbuf,3) & 0xF;
  nmb->header.qdcount = RSVAL(inbuf,4);
  nmb->header.ancount = RSVAL(inbuf,6);
  nmb->header.nscount = RSVAL(inbuf,8);
  nmb->header.arcount = RSVAL(inbuf,10);
  
  if (nmb->header.qdcount) {
    offset = parse_nmb_name(inbuf,12,length,&nmb->question.question_name);
    if (!offset) return(False);

    if (length - (12+offset) < 4) return(False);
    nmb->question.question_type = RSVAL(inbuf,12+offset);
    nmb->question.question_class = RSVAL(inbuf,12+offset+2);

    offset += 12+4;
  } else {