nmblib.c

samba-3.0.22.tar.gz 编译smb服务器的源码

	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);

	/* Paranioa. Ensure the last 2 bytes in the dgram buffer are
	   zero. This should be true anyway, just enforce it for paranioa sake. JRA. */
	SMB_ASSERT(dgram->datasize <= (sizeof(dgram->data)-2));
	memset(&dgram->data[sizeof(dgram->data)-2], '\0', 2);

	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 {
		offset = 12;
	}

	/* and any resource records */
	if (nmb->header.ancount && !parse_alloc_res_rec(inbuf,&offset,length,&nmb->answers,
					nmb->header.ancount))
		return(False);

	if (nmb->header.nscount && !parse_alloc_res_rec(inbuf,&offset,length,&nmb->nsrecs,
					nmb->header.nscount))
		return(False);
  
	if (nmb->header.arcount && !parse_alloc_res_rec(inbuf,&offset,length,&nmb->additional,
					nmb->header.arcount))
		return(False);

	return(True);
}

/*******************************************************************
 'Copy constructor' for an nmb packet.
******************************************************************/

static struct packet_struct *copy_nmb_packet(struct packet_struct *packet)
{  
	struct nmb_packet *nmb;
	struct nmb_packet *copy_nmb;
	struct packet_struct *pkt_copy;

	if(( pkt_copy = SMB_MALLOC_P(struct packet_struct)) == NULL) {
		DEBUG(0,("copy_nmb_packet: malloc fail.\n"));
		return NULL;
	}

	/* Structure copy of entire thing. */

	*pkt_copy = *packet;

	/* Ensure this copy is not locked. */
	pkt_copy->locked = False;

	/* Ensure this copy has no resource records. */
	nmb = &packet->packet.nmb;
	copy_nmb = &pkt_copy->packet.nmb;

	copy_nmb->answers = NULL;
	copy_nmb->nsrecs = NULL;
	copy_nmb->additional = NULL;

	/* Now copy any resource records. */

	if (nmb->answers) {
		if((copy_nmb->answers = SMB_MALLOC_ARRAY(struct res_rec,nmb->header.ancount)) == NULL)
			goto free_and_exit;
		memcpy((char *)copy_nmb->answers, (char *)nmb->answers, 
				nmb->header.ancount * sizeof(struct res_rec));
	}
	if (nmb->nsrecs) {
		if((copy_nmb->nsrecs = SMB_MALLOC_ARRAY(struct res_rec, nmb->header.nscount)) == NULL)
			goto free_and_exit;
		memcpy((char *)copy_nmb->nsrecs, (char *)nmb->nsrecs, 
				nmb->header.nscount * sizeof(struct res_rec));
	}
	if (nmb->additional) {
		if((copy_nmb->additional = SMB_MALLOC_ARRAY(struct res_rec, nmb->header.arcount)) == NULL)
			goto free_and_exit;
		memcpy((char *)copy_nmb->additional, (char *)nmb->additional, 
				nmb->header.arcount * sizeof(struct res_rec));
	}

	return pkt_copy;

 free_and_exit:

	SAFE_FREE(copy_nmb->answers);
	SAFE_FREE(copy_nmb->nsrecs);
	SAFE_FREE(copy_nmb->additional);
	SAFE_FREE(pkt_copy);

	DEBUG(0,("copy_nmb_packet: malloc fail in resource records.\n"));
	return NULL;
}

/*******************************************************************
  'Copy constructor' for a dgram packet.
******************************************************************/

static struct packet_struct *copy_dgram_packet(struct packet_struct *packet)
{ 
	struct packet_struct *pkt_copy;

	if(( pkt_copy = SMB_MALLOC_P(struct packet_struct)) == NULL) {
		DEBUG(0,("copy_dgram_packet: malloc fail.\n"));
		return NULL;
	}

	/* Structure copy of entire thing. */

	*pkt_copy = *packet;

	/* Ensure this copy is not locked. */
	pkt_copy->locked = False;

	/* There are no additional pointers in a dgram packet,
		we are finished. */
	return pkt_copy;
}

/*******************************************************************
 'Copy constructor' for a generic packet.
******************************************************************/

struct packet_struct *copy_packet(struct packet_struct *packet)
{  
	if(packet->packet_type == NMB_PACKET)
		return copy_nmb_packet(packet);
	else if (packet->packet_type == DGRAM_PACKET)
		return copy_dgram_packet(packet);
	return NULL;
}
 
/*******************************************************************
 Free up any resources associated with an nmb packet.
******************************************************************/

static void free_nmb_packet(struct nmb_packet *nmb)
{  
	SAFE_FREE(nmb->answers);
	SAFE_FREE(nmb->nsrecs);
	SAFE_FREE(nmb->additional);
}

/*******************************************************************
 Free up any resources associated with a dgram packet.
******************************************************************/

static void free_dgram_packet(struct dgram_packet *nmb)
{  
	/* We have nothing to do for a dgram packet. */
}

/*******************************************************************
 Free up any resources associated with a packet.
******************************************************************/

void free_packet(struct packet_struct *packet)
{  
	if (packet->locked) 
		return;
	if (packet->packet_type == NMB_PACKET)
		free_nmb_packet(&packet->packet.nmb);
	else if (packet->packet_type == DGRAM_PACKET)
		free_dgram_packet(&packet->packet.dgram);
	ZERO_STRUCTPN(packet);
	SAFE_FREE(packet);
}

/*******************************************************************
 Parse a packet buffer into a packet structure.
******************************************************************/

struct packet_struct *parse_packet(char *buf,int length,
				   enum packet_type packet_type)
{
	struct packet_struct *p;
	BOOL ok=False;

	p = SMB_MALLOC_P(struct packet_struct);
	if (!p)
		return(NULL);

	p->next = NULL;
	p->prev = NULL;
	p->ip = lastip;
	p->port = lastport;
	p->locked = False;
	p->timestamp = time(NULL);
	p->packet_type = packet_type;

	switch (packet_type) {
	case NMB_PACKET:
		ok = parse_nmb(buf,length,&p->packet.nmb);
		break;
		
	case DGRAM_PACKET:
		ok = parse_dgram(buf,length,&p->packet.dgram);
		break;
	}

	if (!ok) {
		free_packet(p);
		return NULL;
	}

	return p;
}

/*******************************************************************
 Read a packet from a socket and parse it, returning a packet ready
 to be used or put on the queue. This assumes a UDP socket.
******************************************************************/

struct packet_struct *read_packet(int fd,enum packet_type packet_type)
{
	struct packet_struct *packet;
	char buf[MAX_DGRAM_SIZE];
	int length;
	
	length = read_udp_socket(fd,buf,sizeof(buf));
	if (length < MIN_DGRAM_SIZE)
		return(NULL);
	
	packet = parse_packet(buf, length, packet_type);
	if (!packet)
		return NULL;

	packet->fd = fd;
	
	num_good_receives++;
	
	DEBUG(5,("Received a packet of len %d from (%s) port %d\n",
		 length, inet_ntoa(packet->ip), packet->port ) );
	
	return(packet);
}
					 
/*******************************************************************
 Send a udp packet on a already open socket.
******************************************************************/

static BOOL send_udp(int fd,char *buf,int len,struct in_addr ip,int port)
{
	BOOL ret = False;
	int i;
	struct sockaddr_in sock_out;

	/* set the address and port */
	memset((char *)&sock_out,'\0',sizeof(sock_out));
	putip((char *)&sock_out.sin_addr,(char *)&ip);
	sock_out.sin_port = htons( port );
	sock_out.sin_family = AF_INET;
  
	DEBUG( 5, ( "Sending a packet of len %d to (%s) on port %d\n",
			len, inet_ntoa(ip), port ) );

	/*
	 * Patch to fix asynch error notifications from Linux kernel.
	 */
	
	for (i = 0; i < 5; i++) {
		ret = (sendto(fd,buf,len,0,(struct sockaddr *)&sock_out, sizeof(sock_out)) >= 0);
		if (ret || errno != ECONNREFUSED)
			break;
	}

	if (!ret)
		DEBUG(0,("Packet send failed to %s(%d) ERRNO=%s\n",
			inet_ntoa(ip),port,strerror(errno)));

	if (ret)
		num_good_sends++;

	return(ret);
}

/*******************************************************************
 Build a dgram packet ready for sending.

 XXXX This currently doesn't handle packets too big for one
 datagram. It should split them and use the packet_offset, more and
 first flags to handle the fragmentation. Yuck.

   [...but it isn't clear that we would ever need to send a
   a fragmented NBT Datagram.  The IP layer does its own
   fragmentation to ensure that messages can fit into the path
   MTU.  It *is* important to be able to receive and rebuild
   fragmented NBT datagrams, just in case someone out there
   really has implemented this 'feature'.  crh -)------ ]

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

static int build_dgram(char *buf,struct packet_struct *p)
{
	struct dgram_packet *dgram = &p->packet.dgram;
	unsigned char *ubuf = (unsigned char *)buf;
	int offset=0;

	/* put in the header */
	ubuf[0] = dgram->header.msg_type;
	ubuf[1] = (((int)dgram->header.flags.node_type)<<2);
	if (dgram->header.flags.more)
		ubuf[1] |= 1;
	if (dgram->header.flags.first)
		ubuf[1] |= 2;
	RSSVAL(ubuf,2,dgram->header.dgm_id);
	putip(ubuf+4,(char *)&dgram->header.source_ip);
	RSSVAL(ubuf,8,dgram->header.source_port);
	RSSVAL(ubuf,12,dgram->header.packet_offset);

	offset = 14;

	if (dgram->header.msg_type == 0x10 ||
			dgram->header.msg_type == 0x11 ||
			dgram->header.msg_type == 0x12) {      
		offset += put_nmb_name((char *)ubuf,offset,&dgram->source_name);
		offset += put_nmb_name((char *)ubuf,offset,&dgram->dest_name);
	}

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

	/* automatically set the dgm_length
	 * NOTE: RFC1002 says the dgm_length does *not*
	 *       include the fourteen-byte header. crh
	 */
	dgram->header.dgm_length = (offset - 14);
	RSSVAL(ubuf,10,dgram->header.dgm_length); 

	return(offset);
}

/*******************************************************************
 Build a nmb name
*******************************************************************/

void make_nmb_name( struct nmb_name *n, const char *name, int type)
{
	fstring unix_name;
	memset( (char *)n, '\0', sizeof(struct nmb_name) );
	fstrcpy(unix_name, name);
	strupper_m(unix_name);
	push_ascii(n->name, unix_name, sizeof(n->name), STR_TERMINATE);
	n->name_type = (unsigned int)type & 0xFF;
	push_ascii(n->scope,  global_scope(), 64, STR_TERMINATE);
}

/*******************************************************************
  Compare two nmb names
******************************************************************/

BOOL nmb_name_equal(struct nmb_name *n1, struct nmb_name *n2)
{
	return ((n1->name_type == n2->name_type) &&
		strequal(n1->name ,n2->name ) &&
		strequal(n1->scope,n2->scope));
}

/*******************************************************************
 Build a nmb packet ready for sending.

 XXXX this currently relies on not being passed something that expands
 to a packet too big for the buffer. Eventually this should be
 changed to set the trunc bit so the receiver can request the rest
 via tcp (when that becomes supported)
******************************************************************/

static int build_nmb(char *buf,struct packet_struct *p)
{
	struct nmb_packet *nmb = &p->packet.nmb;
	unsigned char *ubuf = (unsigned char *)buf;
	int offset=0;

	/* put in the header */