Пример #1
0
/*! \brief Parse DNS NAPTR record used in ENUM ---*/
static int parse_naptr(unsigned char *dst, int dstsize, char *tech, int techsize, unsigned char *answer, int len, unsigned char *naptrinput)
{
	char tech_return[80];
	char *oanswer = (char *)answer;
	char flags[512] = "";
	char services[512] = "";
	char *p;
	char regexp[512] = "";
	char repl[512] = "";
	char tempdst[512] = "";
	char errbuff[512] = "";
	char delim;
	char *delim2;
	char *pattern, *subst, *d;
	int res;
	int regexp_len, rc;
	static const int max_bt = 10; /* max num of regexp backreference allowed, must remain 10 to guarantee a valid backreference index */
	int size, matchindex; /* size is the size of the backreference sub. */
	size_t d_len = sizeof(tempdst) - 1;
	regex_t preg;
	regmatch_t pmatch[max_bt];

	tech_return[0] = '\0';
	dst[0] = '\0';

	if (len < sizeof(struct naptr)) {
		ast_log(LOG_WARNING, "NAPTR record length too short\n");
		return -1;
	}
	answer += sizeof(struct naptr);
	len -= sizeof(struct naptr);
	if ((res = parse_ie(flags, sizeof(flags) - 1, answer, len)) < 0) {
		ast_log(LOG_WARNING, "Failed to get flags from NAPTR record\n");
		return -1;
	} else {
		answer += res;
		len -= res;
	}

	if ((res = parse_ie(services, sizeof(services) - 1, answer, len)) < 0) {
		ast_log(LOG_WARNING, "Failed to get services from NAPTR record\n");
		return -1;
	} else {
		answer += res;
		len -= res;
	}
	if ((res = parse_ie(regexp, sizeof(regexp) - 1, answer, len)) < 0) {
		ast_log(LOG_WARNING, "Failed to get regexp from NAPTR record\n");
		return -1;
	} else {
		answer += res;
		len -= res;
	}

	if ((res = dn_expand((unsigned char *)oanswer, (unsigned char *)answer + len, (unsigned char *)answer, repl, sizeof(repl) - 1)) < 0) {
		ast_log(LOG_WARNING, "Failed to expand hostname\n");
		return -1;
	}

	ast_debug(3, "NAPTR input='%s', flags='%s', services='%s', regexp='%s', repl='%s'\n",
		naptrinput, flags, services, regexp, repl);


	if (tolower(flags[0]) != 'u') {
		ast_log(LOG_WARNING, "NAPTR Flag must be 'U' or 'u'.\n");
		return -1;
	}

	p = strstr(services, "e2u+");
	if (p == NULL)
		p = strstr(services, "E2U+");
	if (p){
		p = p + 4;
		if (strchr(p, ':')){
			p = strchr(p, ':') + 1;
		}
		ast_copy_string(tech_return, p, sizeof(tech_return));
	} else {

		p = strstr(services, "+e2u");
		if (p == NULL)
			p = strstr(services, "+E2U");
		if (p) {
			*p = 0;
			p = strchr(services, ':');
			if (p)
				*p = 0;
			ast_copy_string(tech_return, services, sizeof(tech_return));
		}
	}

	regexp_len = strlen(regexp);
	if (regexp_len < 7) {
		ast_log(LOG_WARNING, "Regex too short to be meaningful.\n");
		return -1;
	}

	/* this takes the first character of the regexp (which is a delimiter)
	 * and uses that character to find the index of the second delimiter */
	delim = regexp[0];
	delim2 = strchr(regexp + 1, delim);
	if ((delim2 == NULL) || (regexp[regexp_len - 1] != delim)) {  /* is the second delimiter found, and is the end of the regexp a delimiter */
		ast_log(LOG_WARNING, "Regex delimiter error (on \"%s\").\n", regexp);
		return -1;
	} else if (strchr((delim2 + 1), delim) == NULL) { /* if the second delimiter is found, make sure there is a third instance.  this could be the end one instead of the middle */
		ast_log(LOG_WARNING, "Regex delimiter error (on \"%s\").\n", regexp);
		return -1;
	}
	pattern = regexp + 1;   /* pattern is the regex without the begining and ending delimiter */
	*delim2 = 0;    /* zero out the middle delimiter */
	subst   = delim2 + 1; /* dst substring is everything after the second delimiter. */
	regexp[regexp_len - 1] = 0; /* zero out the last delimiter */

/*
 * now do the regex wizardry.
 */

	if (regcomp(&preg, pattern, REG_EXTENDED | REG_NEWLINE)) {
		ast_log(LOG_WARNING, "NAPTR Regex compilation error (regex = \"%s\").\n", regexp);
		return -1;
	}

	if (preg.re_nsub > ARRAY_LEN(pmatch)) {
		ast_log(LOG_WARNING, "NAPTR Regex compilation error: too many subs.\n");
		regfree(&preg);
		return -1;
	}
	/* pmatch is an array containing the substring indexes for the regex backreference sub.
	 * max_bt is the maximum number of backreferences allowed to be stored in pmatch */
	if ((rc = regexec(&preg, (char *) naptrinput, max_bt, pmatch, 0))) {
		regerror(rc, &preg, errbuff, sizeof(errbuff));
		ast_log(LOG_WARNING, "NAPTR Regex match failed. Reason: %s\n", errbuff);
		regfree(&preg);
		return -1;
	}
	regfree(&preg);

	d = tempdst;
	d_len--;

	/* perform the backreference sub. Search the subst for backreferences,
	 * when a backreference is found, retrieve the backreferences number.
	 * use the backreference number as an index for pmatch to retrieve the
	 * beginning and ending indexes of the substring to insert as the backreference.
	 * if no backreference is found, continue copying the subst into tempdst */
	while (*subst && (d_len > 0)) {
		if ((subst[0] == '\\') && isdigit(subst[1])) { /* is this character the beginning of a backreference */
			matchindex = (int) (subst[1] - '0');
			if (matchindex >= ARRAY_LEN(pmatch)) {
				ast_log(LOG_WARNING, "Error during regex substitution. Invalid pmatch index.\n");
				return -1;
			}
			/* pmatch len is 10. we are garanteed a single char 0-9 is a valid index */
			size = pmatch[matchindex].rm_eo - pmatch[matchindex].rm_so;
			if (size > d_len) {
				ast_log(LOG_WARNING, "Not enough space during NAPTR regex substitution.\n");
				return -1;
			}
			/* are the pmatch indexes valid for the input length */
			if ((strlen((char *) naptrinput) >= pmatch[matchindex].rm_eo) && (pmatch[matchindex].rm_so <= pmatch[matchindex].rm_eo)) {
				memcpy(d, (naptrinput + (int) pmatch[matchindex].rm_so), size);  /* copy input substring into backreference marker */
				d_len -= size;
				subst += 2;  /* skip over backreference characters to next valid character */
				d += size;
			} else {
				ast_log(LOG_WARNING, "Error during regex substitution. Invalid backreference index.\n");
				return -1;
			}
		} else if (isprint(*subst)) {
			*d++ = *subst++;
			d_len--;
		} else {
			ast_log(LOG_WARNING, "Error during regex substitution.\n");
			return -1;
		}
	}
	*d = 0;
	ast_copy_string((char *) dst, tempdst, dstsize);
	dst[dstsize - 1] = '\0';

	if (*tech != '\0'){ /* check if it is requested NAPTR */
		if (!strncasecmp(tech, "ALL", techsize)){
			return 0; /* return or count any RR */
		}
		if (!strncasecmp(tech_return, tech, sizeof(tech_return) < techsize ? sizeof(tech_return): techsize)){
			ast_copy_string(tech, tech_return, techsize);
			return 0; /* we got our RR */
		} else { /* go to the next RR in the DNS answer */
			return 1;
		}
	}

	/* tech was not specified, return first parsed RR */
	ast_copy_string(tech, tech_return, techsize);

	return 0;
}
Пример #2
0
/*--- parse_naptr: Parse DNS NAPTR record used in ENUM ---*/
static int parse_naptr(unsigned char *dst, int dstsize, char *tech, int techsize, unsigned char *answer, int len, unsigned char *naptrinput)
{
	char tech_return[80];
	char *oanswer = answer;
	char flags[512] = "";
	char services[512] = "";
	char *p;
	char regexp[512] = "";
	char repl[512] = "";
	char temp[512] = "";
	char delim;
	char *delim2;
	char *pattern, *subst, *d;
	int res;
	int regexp_len, size, backref;
	int d_len = sizeof(temp) - 1;
	regex_t preg;
	regmatch_t pmatch[9];

	tech_return[0] = '\0';

	dst[0] = '\0';

	if (len < sizeof(struct naptr)) {
		ast_log(LOG_WARNING, "NAPTR record length too short\n");
		return -1;
	}
	answer += sizeof(struct naptr);
	len -= sizeof(struct naptr);
	if ((res = parse_ie(flags, sizeof(flags) - 1, answer, len)) < 0) {
		ast_log(LOG_WARNING, "Failed to get flags from NAPTR record\n");
		return -1;
	} else {
		answer += res;
		len -= res;
	}
	if ((res = parse_ie(services, sizeof(services) - 1, answer, len)) < 0) {
		ast_log(LOG_WARNING, "Failed to get services from NAPTR record\n");
		return -1;
	} else {
		answer += res;
		len -= res;
	}
	if ((res = parse_ie(regexp, sizeof(regexp) - 1, answer, len)) < 0) {
		ast_log(LOG_WARNING, "Failed to get regexp from NAPTR record\n");
		return -1;
	} else {
		answer += res;
		len -= res;
	}

	if ((res = dn_expand((unsigned char *)oanswer, (unsigned char *)answer + len, (unsigned char *)answer, repl, sizeof(repl) - 1)) < 0) {
		ast_log(LOG_WARNING, "Failed to expand hostname\n");
		return -1;
	}

	if (option_debug > 2)	/* Advanced NAPTR debugging */
		ast_log(LOG_DEBUG, "NAPTR input='%s', flags='%s', services='%s', regexp='%s', repl='%s'\n",
			naptrinput, flags, services, regexp, repl);

	if (tolower(flags[0]) != 'u') {
		ast_log(LOG_WARNING, "NAPTR Flag must be 'U' or 'u'.\n");
		return -1;
	}

	p = strstr(services, "e2u+");
	if (p == NULL)
		p = strstr(services, "E2U+");
	if (p){
		p = p + 4;
		if (strchr(p, ':')){
			p = strchr(p, ':') + 1;
		}
		ast_copy_string(tech_return, p, sizeof(tech_return));
	} else {

		p = strstr(services, "+e2u");
		if (p == NULL)
			p = strstr(services, "+E2U");
		if (p) {
			*p = 0;
			p = strchr(services, ':');
			if (p)
				*p = 0;
			ast_copy_string(tech_return, services, sizeof(tech_return));
		}
	}

	/* DEDBUGGING STUB
	ast_copy_string(regexp, "!^\\+43(.*)$!\\[email protected]!", sizeof(regexp) - 1);
	*/

	regexp_len = strlen(regexp);
	if (regexp_len < 7) {
		ast_log(LOG_WARNING, "Regex too short to be meaningful.\n");
		return -1;
	}


	delim = regexp[0];
	delim2 = strchr(regexp + 1, delim);
	if ((delim2 == NULL) || (regexp[regexp_len-1] != delim)) {
		ast_log(LOG_WARNING, "Regex delimiter error (on \"%s\").\n",regexp);
		return -1;
	}

	pattern = regexp + 1;
	*delim2 = 0;
	subst   = delim2 + 1;
	regexp[regexp_len-1] = 0;

/*
 * now do the regex wizardry.
 */

	if (regcomp(&preg, pattern, REG_EXTENDED | REG_NEWLINE)) {
		ast_log(LOG_WARNING, "NAPTR Regex compilation error (regex = \"%s\").\n",regexp);
		return -1;
	}

	if (preg.re_nsub > 9) {
		ast_log(LOG_WARNING, "NAPTR Regex compilation error: too many subs.\n");
		regfree(&preg);
		return -1;
	}

	if (regexec(&preg, naptrinput, 9, pmatch, 0)) {
		ast_log(LOG_WARNING, "NAPTR Regex match failed.\n");
		regfree(&preg);
		return -1;
	}
	regfree(&preg);

	d = temp;
	d_len--;
	while (*subst && (d_len > 0)) {
		if ((subst[0] == '\\') && isdigit(subst[1]) && (pmatch[subst[1]-'0'].rm_so != -1)) {
			backref = subst[1]-'0';
			size = pmatch[backref].rm_eo - pmatch[backref].rm_so;
			if (size > d_len) {
				ast_log(LOG_WARNING, "Not enough space during NAPTR regex substitution.\n");
				return -1;
				}
			memcpy(d, naptrinput + pmatch[backref].rm_so, size);
			d += size;
			d_len -= size;
			subst += 2;
		} else if (isprint(*subst)) {
			*d++ = *subst++;
			d_len--;
		} else {
			ast_log(LOG_WARNING, "Error during regex substitution.\n");
			return -1;
		}
	}
	*d = 0;
	ast_copy_string(dst, temp, dstsize);
	dst[dstsize - 1] = '\0';

	if (*tech != '\0'){ /* check if it is requested NAPTR */
		if (!strncasecmp(tech, "ALL", techsize)){
			return 1; /* return or count any RR */
		}
		if (!strncasecmp(tech_return, tech, sizeof(tech_return)<techsize?sizeof(tech_return):techsize)){
			ast_copy_string(tech, tech_return, techsize);
			return 1; /* we got out RR */
		} else { /* go to the next RR in the DNS answer */
			return 0;
		}
	}

	/* tech was not specified, return first parsed RR */
	ast_copy_string(tech, tech_return, techsize);

	return 1;
}