ns_name.c

bind 9.3结合mysql数据库

	lpp = cpp = NULL;
	if (dnptrs != NULL) {
		if ((msg = *dnptrs++) != NULL) {
			for (cpp = dnptrs; *cpp != NULL; cpp++)
				(void)NULL;
			lpp = cpp;	/* end of list to search */
		}
	} else
		msg = NULL;

	/* make sure the domain we are about to add is legal */
	l = 0;
	do {
		int l0;

		n = *srcp;
		if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
			errno = EMSGSIZE;
			return (-1);
		}
		if ((l0 = labellen(srcp)) < 0) {
			errno = EINVAL;
			return(-1);
		}
		l += l0 + 1;
		if (l > MAXCDNAME) {
			errno = EMSGSIZE;
			return (-1);
		}
		srcp += l0 + 1;
	} while (n != 0);

	/* from here on we need to reset compression pointer array on error */
	srcp = src;
	do {
		/* Look to see if we can use pointers. */
		n = *srcp;
		if (n != 0 && msg != NULL) {
			l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
				    (const u_char * const *)lpp);
			if (l >= 0) {
				if (dstp + 1 >= eob) {
					goto cleanup;
				}
				*dstp++ = (l >> 8) | NS_CMPRSFLGS;
				*dstp++ = l % 256;
				return (dstp - dst);
			}
			/* Not found, save it. */
			if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
			    (dstp - msg) < 0x4000 && first) {
				*cpp++ = dstp;
				*cpp = NULL;
				first = 0;
			}
		}
		/* copy label to buffer */
		if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
			/* Should not happen. */
			goto cleanup;
		}
		n = labellen(srcp);
		if (dstp + 1 + n >= eob) {
			goto cleanup;
		}
		memcpy(dstp, srcp, n + 1);
		srcp += n + 1;
		dstp += n + 1;
	} while (n != 0);

	if (dstp > eob) {
cleanup:
		if (msg != NULL)
			*lpp = NULL;
		errno = EMSGSIZE;
		return (-1);
	} 
	return (dstp - dst);
}

/*
 * ns_name_uncompress(msg, eom, src, dst, dstsiz)
 *	Expand compressed domain name to presentation format.
 * return:
 *	Number of bytes read out of `src', or -1 (with errno set).
 * note:
 *	Root domain returns as "." not "".
 */
int
ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
		   char *dst, size_t dstsiz)
{
	u_char tmp[NS_MAXCDNAME];
	int n;
	
	if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
		return (-1);
	if (ns_name_ntop(tmp, dst, dstsiz) == -1)
		return (-1);
	return (n);
}

/*
 * ns_name_compress(src, dst, dstsiz, dnptrs, lastdnptr)
 *	Compress a domain name into wire format, using compression pointers.
 * return:
 *	Number of bytes consumed in `dst' or -1 (with errno set).
 * notes:
 *	'dnptrs' is an array of pointers to previous compressed names.
 *	dnptrs[0] is a pointer to the beginning of the message.
 *	The list ends with NULL.  'lastdnptr' is a pointer to the end of the
 *	array pointed to by 'dnptrs'. Side effect is to update the list of
 *	pointers for labels inserted into the message as we compress the name.
 *	If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
 *	is NULL, we don't update the list.
 */
int
ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
		 const u_char **dnptrs, const u_char **lastdnptr)
{
	u_char tmp[NS_MAXCDNAME];

	if (ns_name_pton(src, tmp, sizeof tmp) == -1)
		return (-1);
	return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
}

/*
 * Reset dnptrs so that there are no active references to pointers at or
 * after src.
 */
void
ns_name_rollback(const u_char *src, const u_char **dnptrs,
		 const u_char **lastdnptr)
{
	while (dnptrs < lastdnptr && *dnptrs != NULL) {
		if (*dnptrs >= src) {
			*dnptrs = NULL;
			break;
		}
		dnptrs++;
	}
}

/*
 * ns_name_skip(ptrptr, eom)
 *	Advance *ptrptr to skip over the compressed name it points at.
 * return:
 *	0 on success, -1 (with errno set) on failure.
 */
int
ns_name_skip(const u_char **ptrptr, const u_char *eom)
{
	const u_char *cp;
	u_int n;
	int l;

	cp = *ptrptr;
	while (cp < eom && (n = *cp++) != 0) {
		/* Check for indirection. */
		switch (n & NS_CMPRSFLGS) {
		case 0:			/* normal case, n == len */
			cp += n;
			continue;
		case NS_TYPE_ELT: /* EDNS0 extended label */
			if ((l = labellen(cp - 1)) < 0) {
				errno = EMSGSIZE; /* XXX */
				return(-1);
			}
			cp += l;
			continue;
		case NS_CMPRSFLGS:	/* indirection */
			cp++;
			break;
		default:		/* illegal type */
			errno = EMSGSIZE;
			return (-1);
		}
		break;
	}
	if (cp > eom) {
		errno = EMSGSIZE;
		return (-1);
	}
	*ptrptr = cp;
	return (0);
}

/* Private. */

/*
 * special(ch)
 *	Thinking in noninternationalized USASCII (per the DNS spec),
 *	is this characted special ("in need of quoting") ?
 * return:
 *	boolean.
 */
static int
special(int ch) {
	switch (ch) {
	case 0x22: /* '"' */
	case 0x2E: /* '.' */
	case 0x3B: /* ';' */
	case 0x5C: /* '\\' */
	case 0x28: /* '(' */
	case 0x29: /* ')' */
	/* Special modifiers in zone files. */
	case 0x40: /* '@' */
	case 0x24: /* '$' */
		return (1);
	default:
		return (0);
	}
}

/*
 * printable(ch)
 *	Thinking in noninternationalized USASCII (per the DNS spec),
 *	is this character visible and not a space when printed ?
 * return:
 *	boolean.
 */
static int
printable(int ch) {
	return (ch > 0x20 && ch < 0x7f);
}

/*
 *	Thinking in noninternationalized USASCII (per the DNS spec),
 *	convert this character to lower case if it's upper case.
 */
static int
mklower(int ch) {
	if (ch >= 0x41 && ch <= 0x5A)
		return (ch + 0x20);
	return (ch);
}

/*
 * dn_find(domain, msg, dnptrs, lastdnptr)
 *	Search for the counted-label name in an array of compressed names.
 * return:
 *	offset from msg if found, or -1.
 * notes:
 *	dnptrs is the pointer to the first name on the list,
 *	not the pointer to the start of the message.
 */
static int
dn_find(const u_char *domain, const u_char *msg,
	const u_char * const *dnptrs,
	const u_char * const *lastdnptr)
{
	const u_char *dn, *cp, *sp;
	const u_char * const *cpp;
	u_int n;

	for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
		sp = *cpp;
		/*
		 * terminate search on:
		 * root label
		 * compression pointer
		 * unusable offset
		 */
		while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
		       (sp - msg) < 0x4000) {
			dn = domain;
			cp = sp;
			while ((n = *cp++) != 0) {
				/*
				 * check for indirection
				 */
				switch (n & NS_CMPRSFLGS) {
				case 0:		/* normal case, n == len */
					n = labellen(cp - 1); /* XXX */

					if (n != *dn++)
						goto next;

					for ((void)NULL; n > 0; n--)
						if (mklower(*dn++) !=
						    mklower(*cp++))
							goto next;
					/* Is next root for both ? */
					if (*dn == '\0' && *cp == '\0')
						return (sp - msg);
					if (*dn)
						continue;
					goto next;
				case NS_CMPRSFLGS:	/* indirection */
					cp = msg + (((n & 0x3f) << 8) | *cp);
					break;

				default:	/* illegal type */
					errno = EMSGSIZE;
					return (-1);
				}
			}
 next: ;
			sp += *sp + 1;
		}
	}
	errno = ENOENT;
	return (-1);
}

static int
decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
{
	const unsigned char *cp = *cpp;
	char *beg = dn, tc;
	int b, blen, plen, i;

	if ((blen = (*cp & 0xff)) == 0)
		blen = 256;
	plen = (blen + 3) / 4;
	plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
	if (dn + plen >= eom)
		return(-1);

	cp++;
	i = SPRINTF((dn, "\\[x"));
	if (i < 0)
		return (-1);
	dn += i;
	for (b = blen; b > 7; b -= 8, cp++) {
		i = SPRINTF((dn, "%02x", *cp & 0xff));
		if (i < 0)
			return (-1);
		dn += i;
	}
	if (b > 4) {
		tc = *cp++;
		i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
		if (i < 0)
			return (-1);
		dn += i;
	} else if (b > 0) {
		tc = *cp++;
		i = SPRINTF((dn, "%1x",
			       ((tc >> 4) & 0x0f) & (0x0f << (4 - b)))); 
		if (i < 0)
			return (-1);
		dn += i;
	}
	i = SPRINTF((dn, "/%d]", blen));
	if (i < 0)
		return (-1);
	dn += i;

	*cpp = cp;
	return(dn - beg);
}

static int
encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
	        unsigned char ** dst, unsigned const char *eom)
{
	int afterslash = 0;
	const char *cp = *bp;
	unsigned char *tp;
	char c;
	const char *beg_blen;
	char *end_blen = NULL;
	int value = 0, count = 0, tbcount = 0, blen = 0;

	beg_blen = end_blen = NULL;

	/* a bitstring must contain at least 2 characters */
	if (end - cp < 2)
		return(EINVAL);

	/* XXX: currently, only hex strings are supported */
	if (*cp++ != 'x')
		return(EINVAL);
	if (!isxdigit((*cp) & 0xff)) /* reject '\[x/BLEN]' */
		return(EINVAL);

	for (tp = *dst + 1; cp < end && tp < eom; cp++) {
		switch((c = *cp)) {
		case ']':	/* end of the bitstring */
			if (afterslash) {
				if (beg_blen == NULL)
					return(EINVAL);
				blen = (int)strtol(beg_blen, &end_blen, 10);
				if (*end_blen != ']')
					return(EINVAL);
			}
			if (count)
				*tp++ = ((value << 4) & 0xff);
			cp++;	/* skip ']' */
			goto done;
		case '/':
			afterslash = 1;
			break;
		default:
			if (afterslash) {
				if (!isdigit(c&0xff))
					return(EINVAL);
				if (beg_blen == NULL) {
					
					if (c == '0') {
						/* blen never begings with 0 */
						return(EINVAL);
					}
					beg_blen = cp;
				}
			} else {
				if (!isxdigit(c&0xff))
					return(EINVAL);
				value <<= 4;
				value += digitvalue[(int)c];
				count += 4;
				tbcount += 4;
				if (tbcount > 256)
					return(EINVAL);
				if (count == 8) {
					*tp++ = value;
					count = 0;
				}
			}
			break;
		}
	}
  done:
	if (cp >= end || tp >= eom)
		return(EMSGSIZE);

	/*
	 * bit length validation:
	 * If a <length> is present, the number of digits in the <bit-data>
	 * MUST be just sufficient to contain the number of bits specified
	 * by the <length>. If there are insignificant bits in a final
	 * hexadecimal or octal digit, they MUST be zero.
	 * RFC 2673, Section 3.2.
	 */
	if (blen > 0) {
		int traillen;

		if (((blen + 3) & ~3) != tbcount)
			return(EINVAL);
		traillen = tbcount - blen; /* between 0 and 3 */
		if (((value << (8 - traillen)) & 0xff) != 0)
			return(EINVAL);
	}
	else
		blen = tbcount;
	if (blen == 256)
		blen = 0;

	/* encode the type and the significant bit fields */
	**labelp = DNS_LABELTYPE_BITSTRING;
	**dst = blen;

	*bp = cp;
	*dst = tp;

	return(0);
}

static int
labellen(const u_char *lp)
{
	int bitlen;
	u_char l = *lp;

	if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
		/* should be avoided by the caller */
		return(-1);
	}

	if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
		if (l == DNS_LABELTYPE_BITSTRING) {
			if ((bitlen = *(lp + 1)) == 0)
				bitlen = 256;
			return((bitlen + 7 ) / 8 + 1);
		}
		return(-1);	/* unknwon ELT */
	}
	return(l);
}