nmblib.c

samba-3.0.22.tar.gz 编译smb服务器的源码

	RSSVAL(ubuf,offset,nmb->header.name_trn_id);
	ubuf[offset+2] = (nmb->header.opcode & 0xF) << 3;
	if (nmb->header.response)
		ubuf[offset+2] |= (1<<7);
	if (nmb->header.nm_flags.authoritative && 
			nmb->header.response)
		ubuf[offset+2] |= 0x4;
	if (nmb->header.nm_flags.trunc)
		ubuf[offset+2] |= 0x2;
	if (nmb->header.nm_flags.recursion_desired)
		ubuf[offset+2] |= 0x1;
	if (nmb->header.nm_flags.recursion_available &&
			nmb->header.response)
		ubuf[offset+3] |= 0x80;
	if (nmb->header.nm_flags.bcast)
		ubuf[offset+3] |= 0x10;
	ubuf[offset+3] |= (nmb->header.rcode & 0xF);

	RSSVAL(ubuf,offset+4,nmb->header.qdcount);
	RSSVAL(ubuf,offset+6,nmb->header.ancount);
	RSSVAL(ubuf,offset+8,nmb->header.nscount);
	RSSVAL(ubuf,offset+10,nmb->header.arcount);
  
	offset += 12;
	if (nmb->header.qdcount) {
		/* XXXX this doesn't handle a qdcount of > 1 */
		offset += put_nmb_name((char *)ubuf,offset,&nmb->question.question_name);
		RSSVAL(ubuf,offset,nmb->question.question_type);
		RSSVAL(ubuf,offset+2,nmb->question.question_class);
		offset += 4;
	}

	if (nmb->header.ancount)
		offset += put_res_rec((char *)ubuf,offset,nmb->answers,
				nmb->header.ancount);

	if (nmb->header.nscount)
		offset += put_res_rec((char *)ubuf,offset,nmb->nsrecs,
				nmb->header.nscount);

	/*
	 * The spec says we must put compressed name pointers
	 * in the following outgoing packets :
	 * NAME_REGISTRATION_REQUEST, NAME_REFRESH_REQUEST,
	 * NAME_RELEASE_REQUEST.
	 */

	if((nmb->header.response == False) &&
			((nmb->header.opcode == NMB_NAME_REG_OPCODE) ||
			(nmb->header.opcode == NMB_NAME_RELEASE_OPCODE) ||
			(nmb->header.opcode == NMB_NAME_REFRESH_OPCODE_8) ||
			(nmb->header.opcode == NMB_NAME_REFRESH_OPCODE_9) ||
			(nmb->header.opcode == NMB_NAME_MULTIHOMED_REG_OPCODE)) &&
			(nmb->header.arcount == 1)) {

		offset += put_compressed_name_ptr(ubuf,offset,nmb->additional,12);

	} else if (nmb->header.arcount) {
		offset += put_res_rec((char *)ubuf,offset,nmb->additional,
			nmb->header.arcount);  
	}
	return(offset);
}

/*******************************************************************
 Linearise a packet.
******************************************************************/

int build_packet(char *buf, struct packet_struct *p)
{
	int len = 0;

	switch (p->packet_type) {
	case NMB_PACKET:
		len = build_nmb(buf,p);
		break;

	case DGRAM_PACKET:
		len = build_dgram(buf,p);
		break;
	}

	return len;
}

/*******************************************************************
 Send a packet_struct.
******************************************************************/

BOOL send_packet(struct packet_struct *p)
{
	char buf[1024];
	int len=0;

	memset(buf,'\0',sizeof(buf));

	len = build_packet(buf, p);

	if (!len)
		return(False);

	return(send_udp(p->fd,buf,len,p->ip,p->port));
}

/****************************************************************************
 Receive a packet with timeout on a open UDP filedescriptor.
 The timeout is in milliseconds
***************************************************************************/

struct packet_struct *receive_packet(int fd,enum packet_type type,int t)
{
	fd_set fds;
	struct timeval timeout;
	int ret;

	FD_ZERO(&fds);
	FD_SET(fd,&fds);
	timeout.tv_sec = t/1000;
	timeout.tv_usec = 1000*(t%1000);

	if ((ret = sys_select_intr(fd+1,&fds,NULL,NULL,&timeout)) == -1) {
		/* errno should be EBADF or EINVAL. */
		DEBUG(0,("select returned -1, errno = %s (%d)\n", strerror(errno), errno));
		return NULL;
	}

	if (ret == 0) /* timeout */
		return NULL;

	if (FD_ISSET(fd,&fds)) 
		return(read_packet(fd,type));
	
	return(NULL);
}

/****************************************************************************
 Receive a UDP/137 packet either via UDP or from the unexpected packet
 queue. The packet must be a reply packet and have the specified trn_id.
 The timeout is in milliseconds.
***************************************************************************/

struct packet_struct *receive_nmb_packet(int fd, int t, int trn_id)
{
	struct packet_struct *p;

	p = receive_packet(fd, NMB_PACKET, t);

	if (p && p->packet.nmb.header.response &&
			p->packet.nmb.header.name_trn_id == trn_id) {
		return p;
	}
	if (p)
		free_packet(p);

	/* try the unexpected packet queue */
	return receive_unexpected(NMB_PACKET, trn_id, NULL);
}

/****************************************************************************
 Receive a UDP/138 packet either via UDP or from the unexpected packet
 queue. The packet must be a reply packet and have the specified mailslot name
 The timeout is in milliseconds.
***************************************************************************/

struct packet_struct *receive_dgram_packet(int fd, int t, const char *mailslot_name)
{
	struct packet_struct *p;

	p = receive_packet(fd, DGRAM_PACKET, t);

	if (p && match_mailslot_name(p, mailslot_name)) {
		return p;
	}
	if (p)
		free_packet(p);

	/* try the unexpected packet queue */
	return receive_unexpected(DGRAM_PACKET, 0, mailslot_name);
}

/****************************************************************************
 See if a datagram has the right mailslot name.
***************************************************************************/

BOOL match_mailslot_name(struct packet_struct *p, const char *mailslot_name)
{
	struct dgram_packet *dgram = &p->packet.dgram;
	char *buf;

	buf = &dgram->data[0];
	buf -= 4;

	buf = smb_buf(buf);

	if (memcmp(buf, mailslot_name, strlen(mailslot_name)+1) == 0) {
		return True;
	}

	return False;
}

/****************************************************************************
 Return the number of bits that match between two 4 character buffers
***************************************************************************/

int matching_quad_bits(unsigned char *p1, unsigned char *p2)
{
	int i, j, ret = 0;
	for (i=0; i<4; i++) {
		if (p1[i] != p2[i])
			break;
		ret += 8;
	}

	if (i==4)
		return ret;

	for (j=0; j<8; j++) {
		if ((p1[i] & (1<<(7-j))) != (p2[i] & (1<<(7-j))))
			break;
		ret++;
	}	
	
	return ret;
}

static unsigned char sort_ip[4];

/****************************************************************************
 Compare two query reply records.
***************************************************************************/

static int name_query_comp(unsigned char *p1, unsigned char *p2)
{
	return matching_quad_bits(p2+2, sort_ip) - matching_quad_bits(p1+2, sort_ip);
}

/****************************************************************************
 Sort a set of 6 byte name query response records so that the IPs that
 have the most leading bits in common with the specified address come first.
***************************************************************************/

void sort_query_replies(char *data, int n, struct in_addr ip)
{
	if (n <= 1)
		return;

	putip(sort_ip, (char *)&ip);

	qsort(data, n, 6, QSORT_CAST name_query_comp);
}

/*******************************************************************
 Convert, possibly using a stupid microsoft-ism which has destroyed
 the transport independence of netbios (for CIFS vendors that usually
 use the Win95-type methods, not for NT to NT communication, which uses
 DCE/RPC and therefore full-length unicode strings...) a dns name into
 a netbios name.

 The netbios name (NOT necessarily null-terminated) is truncated to 15
 characters.

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

char *dns_to_netbios_name(const char *dns_name)
{
	static nstring netbios_name;
	int i;
	StrnCpy(netbios_name, dns_name, MAX_NETBIOSNAME_LEN-1);
	netbios_name[15] = 0;
	
	/* ok.  this is because of a stupid microsoft-ism.  if the called host
	   name contains a '.', microsoft clients expect you to truncate the
	   netbios name up to and including the '.'  this even applies, by
	   mistake, to workgroup (domain) names, which is _really_ daft.
	 */
	for (i = 0; i < 15; i++) {
		if (netbios_name[i] == '.') {
			netbios_name[i] = 0;
			break;
		}
	}

	return netbios_name;
}

/****************************************************************************
 Interpret the weird netbios "name" into a unix fstring. Return the name type.
****************************************************************************/

static int name_interpret(char *in, fstring name)
{
	int ret;
	int len = (*in++) / 2;
	fstring out_string;
	char *out = out_string;

	*out=0;

	if (len > 30 || len<1)
		return(0);

	while (len--) {
		if (in[0] < 'A' || in[0] > 'P' || in[1] < 'A' || in[1] > 'P') {
			*out = 0;
			return(0);
		}
		*out = ((in[0]-'A')<<4) + (in[1]-'A');
		in += 2;
		out++;
	}
	ret = out[-1];
	out[-1] = 0;

#ifdef NETBIOS_SCOPE
	/* Handle any scope names */
	while(*in) {
		*out++ = '.'; /* Scope names are separated by periods */
		len = *(unsigned char *)in++;
		StrnCpy(out, in, len);
		out += len;
		*out=0;
		in += len;
	}
#endif
	pull_ascii_fstring(name, out_string);

	return(ret);
}

/****************************************************************************
 Mangle a name into netbios format.
 Note:  <Out> must be (33 + strlen(scope) + 2) bytes long, at minimum.
****************************************************************************/

int name_mangle( char *In, char *Out, char name_type )
{
	int   i;
	int   len;
	nstring buf;
	char *p = Out;

	/* Safely copy the input string, In, into buf[]. */
	if (strcmp(In,"*") == 0)
		put_name(buf, "*", '\0', 0x00);
	else {
		/* We use an fstring here as mb dos names can expend x3 when
		   going to utf8. */
		fstring buf_unix;
		nstring buf_dos;

		pull_ascii_fstring(buf_unix, In);
		strupper_m(buf_unix);

		push_ascii_nstring(buf_dos, buf_unix);
		put_name(buf, buf_dos, ' ', name_type);
	}

	/* Place the length of the first field into the output buffer. */
	p[0] = 32;
	p++;

	/* Now convert the name to the rfc1001/1002 format. */
	for( i = 0; i < MAX_NETBIOSNAME_LEN; i++ ) {
		p[i*2]     = ( (buf[i] >> 4) & 0x000F ) + 'A';
		p[(i*2)+1] = (buf[i] & 0x000F) + 'A';
	}
	p += 32;
	p[0] = '\0';

	/* Add the scope string. */
	for( i = 0, len = 0; *(global_scope()) != '\0'; i++, len++ ) {
		switch( (global_scope())[i] ) {
			case '\0':
				p[0] = len;
				if( len > 0 )
					p[len+1] = 0;
				return( name_len(Out) );
			case '.':
				p[0] = len;
				p   += (len + 1);
				len  = -1;
				break;
			default:
				p[len+1] = (global_scope())[i];
				break;
		}
	}

	return( name_len(Out) );
}

/****************************************************************************
 Find a pointer to a netbios name.
****************************************************************************/

static char *name_ptr(char *buf,int ofs)
{
	unsigned char c = *(unsigned char *)(buf+ofs);

	if ((c & 0xC0) == 0xC0) {
		uint16 l = RSVAL(buf, ofs) & 0x3FFF;
		DEBUG(5,("name ptr to pos %d from %d is %s\n",l,ofs,buf+l));
		return(buf + l);
	} else {
		return(buf+ofs);
	}
}  

/****************************************************************************
 Extract a netbios name from a buf (into a unix string) return name type.
****************************************************************************/

int name_extract(char *buf,int ofs, fstring name)
{
	char *p = name_ptr(buf,ofs);
	int d = PTR_DIFF(p,buf+ofs);

	name[0] = '\0';
	if (d < -50 || d > 50)
		return(0);
	return(name_interpret(p,name));
}
  
/****************************************************************************
 Return the total storage length of a mangled name.
****************************************************************************/

int name_len(char *s1)
{
	/* NOTE: this argument _must_ be unsigned */
	unsigned char *s = (unsigned char *)s1;
	int len;

	/* If the two high bits of the byte are set, return 2. */
	if (0xC0 == (*s & 0xC0))
		return(2);

	/* Add up the length bytes. */
	for (len = 1; (*s); s += (*s) + 1) {
		len += *s + 1;
		SMB_ASSERT(len < 80);
	}

	return(len);
}