/*! \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;
}
/*--- 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;
}