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asterisk/main/enum.c

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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2006, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* Funding provided by nic.at
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
*
* \brief ENUM Support for Asterisk
*
* \author Mark Spencer <markster@digium.com>
*
* \arg Funding provided by nic.at
*
* \par Enum standards
*
* - NAPTR records: http://ietf.nri.reston.va.us/rfc/rfc2915.txt
* - DNS SRV records: http://www.ietf.org/rfc/rfc2782.txt
* - ENUM http://www.ietf.org/rfc/rfc3761.txt
* - ENUM for H.323: http://www.ietf.org/rfc/rfc3762.txt
* - ENUM SIP: http://www.ietf.org/rfc/rfc3764.txt
* - IANA ENUM Services: http://www.iana.org/assignments/enum-services
*
* - I-ENUM:
* http://tools.ietf.org/wg/enum/draft-ietf-enum-combined/
* http://tools.ietf.org/wg/enum/draft-ietf-enum-branch-location-record/
*
* \par Possible improvement
* \todo Implement a caching mechanism for multile enum lookups
* - See https://issues.asterisk.org/view.php?id=6739
* \todo The service type selection needs to be redone.
*/
/*! \li \ref enum.c uses the configuration file \ref enum.conf
* \addtogroup configuration_file Configuration Files
*/
/*!
* \page enum.conf enum.conf
* \verbinclude enum.conf.sample
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#ifdef __APPLE__
#include <arpa/nameser_compat.h>
#endif
#include <resolv.h>
#include <ctype.h>
#include <regex.h>
#include "asterisk/module.h"
#include "asterisk/enum.h"
#include "asterisk/dns.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/utils.h"
#include "asterisk/manager.h"
#ifdef __APPLE__
#undef T_NAPTR
#define T_NAPTR 35
#endif
#ifdef __APPLE__
#undef T_TXT
#define T_TXT 16
#endif
static char ienum_branchlabel[32] = "i";
/* how to do infrastructure enum branch location resolution? */
#define ENUMLOOKUP_BLR_CC 0
#define ENUMLOOKUP_BLR_TXT 1
#define ENUMLOOKUP_BLR_EBL 2
static int ebl_alg = ENUMLOOKUP_BLR_CC;
/* EBL record provisional type code */
#define T_EBL 65300
AST_MUTEX_DEFINE_STATIC(enumlock);
/*! \brief Determine the length of a country code when given an E.164 string */
/*
* Input: E.164 number w/o leading +
*
* Output: number of digits in the country code
* 0 on invalid number
*
* Algorithm:
* 3 digits is the default length of a country code.
* country codes 1 and 7 are a single digit.
* the following country codes are two digits: 20, 27, 30-34, 36, 39,
* 40, 41, 43-49, 51-58, 60-66, 81, 82, 84, 86, 90-95, 98.
*/
static int cclen(const char *number)
{
int cc;
char digits[3] = "";
if (!number || (strlen(number) < 3)) {
return 0;
}
strncpy(digits, number, 2);
if (!sscanf(digits, "%30d", &cc)) {
return 0;
}
if (cc / 10 == 1 || cc / 10 == 7)
return 1;
if (cc == 20 || cc == 27 || (cc >= 30 && cc <= 34) || cc == 36 ||
cc == 39 || cc == 40 || cc == 41 || (cc >= 40 && cc <= 41) ||
(cc >= 43 && cc <= 49) || (cc >= 51 && cc <= 58) ||
(cc >= 60 && cc <= 66) || cc == 81 || cc == 82 || cc == 84 ||
cc == 86 || (cc >= 90 && cc <= 95) || cc == 98) {
return 2;
}
return 3;
}
struct txt_context {
char txt[1024]; /* TXT record in TXT lookup */
int txtlen; /* Length */
};
/*! \brief Callback for TXT record lookup, /ol version */
static int txt_callback(void *context, unsigned char *answer, int len, unsigned char *fullanswer)
{
struct txt_context *c = context;
unsigned int i;
c->txt[0] = 0; /* default to empty */
c->txtlen = 0;
if (answer == NULL) {
return 0;
}
/* RFC1035:
*
* <character-string> is a single length octet followed by that number of characters.
* TXT-DATA One or more <character-string>s.
*
* We only take the first string here.
*/
i = *answer++;
len -= 1;
if (i > len) { /* illegal packet */
ast_log(LOG_WARNING, "txt_callback: malformed TXT record.\n");
return 0;
}
if (i >= sizeof(c->txt)) { /* too long? */
ast_log(LOG_WARNING, "txt_callback: TXT record too long.\n");
i = sizeof(c->txt) - 1;
}
ast_copy_string(c->txt, (char *)answer, i + 1); /* this handles the \0 termination */
c->txtlen = i;
return 1;
}
/*! \brief Determine the branch location record as stored in a TXT record */
/*
* Input: CC code
*
* Output: number of digits in the number before the i-enum branch
*
* Algorithm: Build <ienum_branchlabel>.c.c.<suffix> and look for a TXT lookup.
* Return atoi(TXT-record).
* Return -1 on not found.
*
*/
static int blr_txt(const char *cc, const char *suffix)
{
struct txt_context context;
char domain[128] = "";
char *p1, *p2;
int ret;
ast_mutex_lock(&enumlock);
ast_verb(4, "blr_txt() cc='%s', suffix='%s', c_bl='%s'\n", cc, suffix, ienum_branchlabel);
if (sizeof(domain) < (strlen(cc) * 2 + strlen(ienum_branchlabel) + strlen(suffix) + 2)) {
ast_mutex_unlock(&enumlock);
ast_log(LOG_WARNING, "ERROR: string sizing in blr_txt.\n");
return -1;
}
p1 = domain + snprintf(domain, sizeof(domain), "%s.", ienum_branchlabel);
ast_mutex_unlock(&enumlock);
for (p2 = (char *) cc + strlen(cc) - 1; p2 >= cc; p2--) {
if (isdigit(*p2)) {
*p1++ = *p2;
*p1++ = '.';
}
}
strcat(p1, suffix);
ast_verb(4, "blr_txt() FQDN for TXT record: %s, cc was %s\n", domain, cc);
ret = ast_search_dns(&context, domain, C_IN, T_TXT, txt_callback);
if (ret > 0) {
ret = atoi(context.txt);
if ((ret >= 0) && (ret < 20)) {
ast_verb(3, "blr_txt() BLR TXT record for %s is %d (apex: %s)\n", cc, ret, suffix);
return ret;
}
}
ast_verb(3, "blr_txt() BLR TXT record for %s not found (apex: %s)\n", cc, suffix);
return -1;
}
struct ebl_context {
unsigned char pos;
char separator[256]; /* label to insert */
int sep_len; /* Length */
char apex[256]; /* new Apex */
int apex_len; /* Length */
};
/*! \brief Callback for EBL record lookup */
static int ebl_callback(void *context, unsigned char *answer, int len, unsigned char *fullanswer)
{
struct ebl_context *c = context;
int i;
c->pos = 0; /* default to empty */
c->separator[0] = 0;
c->sep_len = 0;
c->apex[0] = 0;
c->apex_len = 0;
if (answer == NULL) {
return 0;
}
/* draft-lendl-enum-branch-location-record-00
*
* 0 1 2 3 4 5 6 7
* +--+--+--+--+--+--+--+--+
* | POSITION |
* +--+--+--+--+--+--+--+--+
* / SEPARATOR /
* +--+--+--+--+--+--+--+--+
* / APEX /
* +--+--+--+--+--+--+--+--+
*
* where POSITION is a single byte, SEPARATOR is a <character-string>
* and APEX is a <domain-name>.
*
*/
c->pos = *answer++;
len -= 1;
if ((c->pos > 15) || len < 2) { /* illegal packet */
ast_log(LOG_WARNING, "ebl_callback: malformed EBL record.\n");
return 0;
}
i = *answer++;
len -= 1;
if (i > len) { /* illegal packet */
ast_log(LOG_WARNING, "ebl_callback: malformed EBL record.\n");
return 0;
}
ast_copy_string(c->separator, (char *)answer, i + 1);
c->sep_len = i;
answer += i;
len -= i;
if ((i = dn_expand((unsigned char *)fullanswer, (unsigned char *)answer + len,
(unsigned char *)answer, c->apex, sizeof(c->apex) - 1)) < 0) {
ast_log(LOG_WARNING, "Failed to expand hostname\n");
return 0;
}
c->apex[i] = 0;
c->apex_len = i;
return 1;
}
/*! \brief Evaluate the I-ENUM branch as stored in an EBL record */
/*
* Input: CC code
*
* Output: number of digits in the number before the i-enum branch
*
* Algorithm: Build <ienum_branchlabel>.c.c.<suffix> and look for an EBL record
* Return pos and fill in separator and apex.
* Return -1 on not found.
*
*/
static int blr_ebl(const char *cc, const char *suffix, char *separator, int sep_len, char* apex, int apex_len)
{
struct ebl_context context;
char domain[128] = "";
char *p1,*p2;
int ret;
ast_mutex_lock(&enumlock);
ast_verb(4, "blr_ebl() cc='%s', suffix='%s', c_bl='%s'\n", cc, suffix, ienum_branchlabel);
if (sizeof(domain) < (strlen(cc) * 2 + strlen(ienum_branchlabel) + strlen(suffix) + 2)) {
ast_mutex_unlock(&enumlock);
ast_log(LOG_WARNING, "ERROR: string sizing in blr_EBL.\n");
return -1;
}
p1 = domain + snprintf(domain, sizeof(domain), "%s.", ienum_branchlabel);
ast_mutex_unlock(&enumlock);
for (p2 = (char *) cc + strlen(cc) - 1; p2 >= cc; p2--) {
if (isdigit(*p2)) {
*p1++ = *p2;
*p1++ = '.';
}
}
strcat(p1, suffix);
ast_verb(4, "blr_ebl() FQDN for EBL record: %s, cc was %s\n", domain, cc);
ret = ast_search_dns(&context, domain, C_IN, T_EBL, ebl_callback);
if (ret > 0) {
ret = context.pos;
if ((ret >= 0) && (ret < 20)) {
ast_verb(3, "blr_txt() BLR EBL record for %s is %d/%s/%s)\n", cc, ret, context.separator, context.apex);
ast_copy_string(separator, context.separator, sep_len);
ast_copy_string(apex, context.apex, apex_len);
return ret;
}
}
ast_verb(3, "blr_txt() BLR EBL record for %s not found (apex: %s)\n", cc, suffix);
return -1;
}
/*! \brief Parse NAPTR record information elements */
static unsigned int parse_ie(char *data, unsigned int maxdatalen, unsigned char *src, unsigned int srclen)
{
unsigned int len, olen;
len = olen = (unsigned int) src[0];
src++;
srclen--;
if (len > srclen) {
ast_log(LOG_WARNING, "ENUM parsing failed: Wanted %u characters, got %u\n", len, srclen);
return -1;
}
if (len > maxdatalen)
len = maxdatalen;
memcpy(data, src, len);
return olen + 1;
}
/*! \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;
int re_flags = REG_EXTENDED | REG_NEWLINE;
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] != 'i' || regexp[regexp_len - 2] != delim)
&& regexp[regexp_len - 1] != delim)) {
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;
}
/* Make the regex case-insensitive if the 'i' flag is present. This assumes you
* aren't using 'i' as a delimiter which, although dubious, does not appear to be
* explicitly non-compliant */
if (regexp[regexp_len - 1] == 'i') {
re_flags |= REG_ICASE;
}
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, re_flags)) {
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 guaranteed 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;
}
/* do not return requested value, just count RRs and return thei number in dst */
#define ENUMLOOKUP_OPTIONS_COUNT 1
/* do an ISN style lookup */
#define ENUMLOOKUP_OPTIONS_ISN 2
/* do a infrastructure ENUM lookup */
#define ENUMLOOKUP_OPTIONS_IENUM 4
/* do a direct DNS lookup: no reversal */
#define ENUMLOOKUP_OPTIONS_DIRECT 8
/*! \brief Callback from ENUM lookup function */
static int enum_callback(void *context, unsigned char *answer, int len, unsigned char *fullanswer)
{
struct enum_context *c = context;
void *p = NULL;
int res;
res = parse_naptr((unsigned char *)c->dst, c->dstlen, c->tech, c->techlen, answer, len, (unsigned char *)c->naptrinput);
if (res < 0) {
ast_log(LOG_WARNING, "Failed to parse naptr\n");
return -1;
} else if ((res == 0) && !ast_strlen_zero(c->dst)) { /* ok, we got needed NAPTR */
if (c->options & ENUMLOOKUP_OPTIONS_COUNT) { /* counting RRs */
c->count++;
snprintf(c->dst, c->dstlen, "%d", c->count);
} else {
if ((p = ast_realloc(c->naptr_rrs, sizeof(*c->naptr_rrs) * (c->naptr_rrs_count + 1)))) {
c->naptr_rrs = p;
memcpy(&c->naptr_rrs[c->naptr_rrs_count].naptr, answer, sizeof(c->naptr_rrs->naptr));
c->naptr_rrs[c->naptr_rrs_count].result = ast_strdup(c->dst);
c->naptr_rrs[c->naptr_rrs_count].tech = ast_strdup(c->tech);
c->naptr_rrs[c->naptr_rrs_count].sort_pos = c->naptr_rrs_count;
c->naptr_rrs_count++;
}
c->dst[0] = 0;
}
return 0;
}
return 0;
}
/* ENUM lookup */
int ast_get_enum(struct ast_channel *chan, const char *number, char *dst, int dstlen, char *tech, int techlen, char* suffix, char* options, unsigned int record, struct enum_context **argcontext)
{
struct enum_context *context;
char tmp[512];
char domain[256];
char left[128];
char middle[128];
char naptrinput[128];
char apex[128] = "";
int ret = -1;
/* for ISN rewrite */
char *p1 = NULL;
char *p2 = NULL;
char *p3 = NULL;
int k = 0;
int i = 0;
int z = 0;
int spaceleft = 0;
struct timeval time_start, time_end;
if (ast_strlen_zero(suffix)) {
ast_log(LOG_WARNING, "ast_get_enum need a suffix parameter now.\n");
return -1;
}
ast_debug(2, "num='%s', tech='%s', suffix='%s', options='%s', record=%u\n", number, tech, suffix, options, record);
/*
We don't need that any more, that "n" preceding the number has been replaced by a flag
in the options paramter.
ast_copy_string(naptrinput, number, sizeof(naptrinput));
*/
/*
* The "number" parameter includes a leading '+' if it's a full E.164 number (and not ISN)
* We need to preserve that as the regex inside NAPTRs expect the +.
*
* But for the domain generation, the '+' is a nuisance, so we get rid of it.
*/
ast_copy_string(naptrinput, number[0] == 'n' ? number + 1 : number, sizeof(naptrinput));
if (number[0] == '+') {
number++;
}
if (!(context = ast_calloc(1, sizeof(*context)))) {
return -1;
}
if ((p3 = strchr(naptrinput, '*'))) {
*p3='\0';
}
context->naptrinput = naptrinput; /* The number */
context->dst = dst; /* Return string */
context->dstlen = dstlen;
context->tech = tech;
context->techlen = techlen;
context->options = 0;
context->position = record > 0 ? record : 1;
context->count = 0;
context->naptr_rrs = NULL;
context->naptr_rrs_count = 0;
/*
* Process options:
*
* c Return count, not URI
* i Use infrastructure ENUM
* s Do ISN transformation
* d Direct DNS query: no reversing.
*
*/
if (options != NULL) {
if (strchr(options,'s')) {
context->options |= ENUMLOOKUP_OPTIONS_ISN;
} else if (strchr(options,'i')) {
context->options |= ENUMLOOKUP_OPTIONS_IENUM;
} else if (strchr(options,'d')) {
context->options |= ENUMLOOKUP_OPTIONS_DIRECT;
}
if (strchr(options,'c')) {
context->options |= ENUMLOOKUP_OPTIONS_COUNT;
}
if (strchr(number,'*')) {
context->options |= ENUMLOOKUP_OPTIONS_ISN;
}
}
ast_debug(2, "ENUM options(%s): pos=%d, options='%d'\n", options, context->position, context->options);
ast_debug(1, "n='%s', tech='%s', suffix='%s', options='%d', record='%d'\n",
number, tech, suffix, context->options, context->position);
/*
* This code does more than simple RFC3261 ENUM. All these rewriting
* schemes have in common that they build the FQDN for the NAPTR lookup
* by concatenating
* - a number which needs be flipped and "."-seperated (left)
* - some fixed string (middle)
* - an Apex. (apex)
*
* The RFC3261 ENUM is: left=full number, middle="", apex=from args.
* ISN: number = "middle*left", apex=from args
* I-ENUM: EBL parameters build the split, can change apex
* Direct: left="", middle=argument, apex=from args
*
*/
/* default: the whole number will be flipped, no middle domain component */
ast_copy_string(left, number, sizeof(left));
middle[0] = '\0';
/*
* I-ENUM can change the apex, thus we copy it
*/
ast_copy_string(apex, suffix, sizeof(apex));
/* ISN rewrite */
if ((context->options & ENUMLOOKUP_OPTIONS_ISN) && (p1 = strchr(number, '*'))) {
*p1++ = '\0';
ast_copy_string(left, number, sizeof(left));
ast_copy_string(middle, p1, sizeof(middle) - 1);
strcat(middle, ".");
ast_debug(2, "ISN ENUM: left=%s, middle='%s'\n", left, middle);
/* Direct DNS lookup rewrite */
} else if (context->options & ENUMLOOKUP_OPTIONS_DIRECT) {
left[0] = 0; /* nothing to flip around */
ast_copy_string(middle, number, sizeof(middle) - 1);
strcat(middle, ".");
ast_debug(2, "DIRECT ENUM: middle='%s'\n", middle);
/* Infrastructure ENUM rewrite */
} else if (context->options & ENUMLOOKUP_OPTIONS_IENUM) {
int sdl = 0;
char cc[8];
char sep[256], n_apex[256];
int cc_len = cclen(number);
sdl = cc_len;
ast_mutex_lock(&enumlock);
ast_copy_string(sep, ienum_branchlabel, sizeof(sep)); /* default */
ast_mutex_unlock(&enumlock);
switch (ebl_alg) {
case ENUMLOOKUP_BLR_EBL:
ast_copy_string(cc, number, cc_len); /* cclen() never returns more than 3 */
sdl = blr_ebl(cc, suffix, sep, sizeof(sep) - 1, n_apex, sizeof(n_apex) - 1);
if (sdl >= 0) {
ast_copy_string(apex, n_apex, sizeof(apex));
ast_debug(2, "EBL ENUM: sep=%s, apex='%s'\n", sep, n_apex);
} else {
sdl = cc_len;
}
break;
case ENUMLOOKUP_BLR_TXT:
ast_copy_string(cc, number, cc_len); /* cclen() never returns more than 3 */
sdl = blr_txt(cc, suffix);
if (sdl < 0) {
sdl = cc_len;
}
break;
case ENUMLOOKUP_BLR_CC: /* BLR is at the country-code level */
default:
sdl = cc_len;
break;
}
if (sdl > strlen(number)) { /* Number too short for this sdl? */
ast_log(LOG_WARNING, "I-ENUM: subdomain location %d behind number %s\n", sdl, number);
ast_free(context);
return 0;
}
ast_copy_string(left, number + sdl, sizeof(left));
ast_mutex_lock(&enumlock);
ast_copy_string(middle, sep, sizeof(middle) - 1);
strcat(middle, ".");
ast_mutex_unlock(&enumlock);
/* check the space we need for middle */
if ((sdl * 2 + strlen(middle) + 2) > sizeof(middle)) {
ast_log(LOG_WARNING, "ast_get_enum: not enough space for I-ENUM rewrite.\n");
ast_free(context);
return -1;
}
p1 = middle + strlen(middle);
for (p2 = (char *) number + sdl - 1; p2 >= number; p2--) {
if (isdigit(*p2)) {
*p1++ = *p2;
*p1++ = '.';
}
}
*p1 = '\0';
ast_debug(2, "I-ENUM: cclen=%d, left=%s, middle='%s', apex='%s'\n", cc_len, left, middle, apex);
}
if (strlen(left) * 2 + 2 > sizeof(domain)) {
ast_log(LOG_WARNING, "string to long in ast_get_enum\n");
ast_free(context);
return -1;
}
/* flip left into domain */
p1 = domain;
for (p2 = left + strlen(left); p2 >= left; p2--) {
if (isdigit(*p2)) {
*p1++ = *p2;
*p1++ = '.';
}
}
*p1 = '\0';
if (chan && ast_autoservice_start(chan) < 0) {
ast_free(context);
return -1;
}
spaceleft = sizeof(tmp) - 2;
ast_copy_string(tmp, domain, spaceleft);
spaceleft -= strlen(domain);
if (*middle) {
strncat(tmp, middle, spaceleft);
spaceleft -= strlen(middle);
}
strncat(tmp,apex,spaceleft);
time_start = ast_tvnow();
ret = ast_search_dns(context, tmp, C_IN, T_NAPTR, enum_callback);
time_end = ast_tvnow();
ast_debug(2, "profiling: %s, %s, %" PRIi64 " ms\n",
(ret == 0) ? "OK" : "FAIL", tmp, ast_tvdiff_ms(time_end, time_start));
if (ret < 0) {
ast_debug(1, "No such number found: %s (%s)\n", tmp, strerror(errno));
context->naptr_rrs_count = -1;
strcpy(dst, "0");
ret = 0;
}
if (context->naptr_rrs_count >= context->position && ! (context->options & ENUMLOOKUP_OPTIONS_COUNT)) {
/* sort array by NAPTR order/preference */
for (k = 0; k < context->naptr_rrs_count; k++) {
for (i = 0; i < context->naptr_rrs_count; i++) {
/* use order first and then preference to compare */
if ((ntohs(context->naptr_rrs[k].naptr.order) < ntohs(context->naptr_rrs[i].naptr.order)
&& context->naptr_rrs[k].sort_pos > context->naptr_rrs[i].sort_pos)
|| (ntohs(context->naptr_rrs[k].naptr.order) > ntohs(context->naptr_rrs[i].naptr.order)
&& context->naptr_rrs[k].sort_pos < context->naptr_rrs[i].sort_pos)) {
z = context->naptr_rrs[k].sort_pos;
context->naptr_rrs[k].sort_pos = context->naptr_rrs[i].sort_pos;
context->naptr_rrs[i].sort_pos = z;
continue;
}
if (ntohs(context->naptr_rrs[k].naptr.order) == ntohs(context->naptr_rrs[i].naptr.order)) {
if ((ntohs(context->naptr_rrs[k].naptr.pref) < ntohs(context->naptr_rrs[i].naptr.pref)
&& context->naptr_rrs[k].sort_pos > context->naptr_rrs[i].sort_pos)
|| (ntohs(context->naptr_rrs[k].naptr.pref) > ntohs(context->naptr_rrs[i].naptr.pref)
&& context->naptr_rrs[k].sort_pos < context->naptr_rrs[i].sort_pos)) {
z = context->naptr_rrs[k].sort_pos;
context->naptr_rrs[k].sort_pos = context->naptr_rrs[i].sort_pos;
context->naptr_rrs[i].sort_pos = z;
}
}
}
}
for (k = 0; k < context->naptr_rrs_count; k++) {
if (context->naptr_rrs[k].sort_pos == context->position - 1) {
ast_copy_string(context->dst, context->naptr_rrs[k].result, dstlen);
ast_copy_string(context->tech, context->naptr_rrs[k].tech, techlen);
break;
}
}
} else if (!(context->options & ENUMLOOKUP_OPTIONS_COUNT)) {
context->dst[0] = 0;
} else if ((context->options & ENUMLOOKUP_OPTIONS_COUNT)) {
snprintf(context->dst, context->dstlen, "%d", context->naptr_rrs_count + context->count);
}
if (chan) {
ret |= ast_autoservice_stop(chan);
}
if (!argcontext) {
for (k = 0; k < context->naptr_rrs_count; k++) {
ast_free(context->naptr_rrs[k].result);
ast_free(context->naptr_rrs[k].tech);
}
ast_free(context->naptr_rrs);
ast_free(context);
} else {
*argcontext = context;
}
return ret;
}
/*! \internal
* \brief Format a phone number as a domain in an ENUM-adjacent way.
*
* Creates a domain name suitable for query by:
*
* 1. Removing non-digits
* 2. Adding a '.' between adjacent digits
* 3. Reversing the string
* 4. Appending the specified suffix (or e164.arpa if none is specified)
*/
static char *format_numeric_domain(const char *number, const char *suffix)
{
char *buffer, *dst;
size_t suffix_length;
size_t number_length = strlen(number);
const char *src = number + number_length - 1;
if (!suffix) {
suffix = "e164.arpa";
}
suffix_length = strlen(suffix);
dst = buffer = ast_malloc(
(number_length * 2) /* We need 2 bytes per input digit */
+ suffix_length /* ... plus however long the suffix is */
+ 1 /* ... plus room for the '.' separator */
+ 1 /* ... and room for the \0 byte at the end */);
if (buffer) {
while (src >= number) {
if (isdigit(*src)) {
*dst++ = *src;
*dst++ = '.';
}
src--;
}
/* The length arguments below make sure that the \0 byte is copied into
the final string */
if (*suffix == '.') {
memcpy(dst, &suffix[1], suffix_length);
} else {
memcpy(dst, suffix, suffix_length + 1);
}
}
return buffer;
}
int ast_get_txt(struct ast_channel *chan, const char *number, char *txt, int txtlen, char *suffix)
{
struct txt_context context;
char *domain;
int ret;
int autoservice = 0;
ast_debug(4, "ast_get_txt: Number = '%s', suffix = '%s'\n", number, suffix);
domain = format_numeric_domain(number, suffix);
if (!domain) {
return -1;
}
if (chan) {
/* DNS might take a while, so service the channel while we're blocked */
autoservice = !ast_autoservice_start(chan);
}
ret = ast_search_dns(&context, domain, C_IN, T_TXT, txt_callback);
if (ret > 0) {
ast_copy_string(txt, context.txt, txtlen);
} else {
ast_debug(2, "No such number found in ENUM: %s (%s)\n", domain, strerror(errno));
}
if (autoservice) {
ast_autoservice_stop(chan);
}
ast_free(domain);
return 0;
}
/*! \brief Initialize the ENUM support subsystem */
static int private_enum_init(int reload)
{
struct ast_config *cfg;
const char *string;
struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
if ((cfg = ast_config_load2("enum.conf", "enum", config_flags)) == CONFIG_STATUS_FILEUNCHANGED)
return 0;
if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID) {
return 0;
}
/* Destroy existing list */
ast_mutex_lock(&enumlock);
if (cfg) {
if ((string = ast_variable_retrieve(cfg, "ienum", "branchlabel"))) {
ast_copy_string(ienum_branchlabel, string, sizeof(ienum_branchlabel));
}
if ((string = ast_variable_retrieve(cfg, "ienum", "ebl_alg"))) {
ebl_alg = ENUMLOOKUP_BLR_CC; /* default */
if (!strcasecmp(string, "txt"))
ebl_alg = ENUMLOOKUP_BLR_TXT;
else if (!strcasecmp(string, "ebl"))
ebl_alg = ENUMLOOKUP_BLR_EBL;
else if (!strcasecmp(string, "cc"))
ebl_alg = ENUMLOOKUP_BLR_CC;
else
ast_log(LOG_WARNING, "No valid parameter for ienum/ebl_alg.\n");
}
ast_config_destroy(cfg);
}
ast_mutex_unlock(&enumlock);
return 0;
}
static int load_module(void)
{
return private_enum_init(0) ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
return 0;
}
static int reload_module(void)
{
return private_enum_init(1);
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "ENUM Support",
.support_level = AST_MODULE_SUPPORT_CORE,
.load = load_module,
.unload = unload_module,
.reload = reload_module,
.load_pri = AST_MODPRI_CORE,
.requires = "extconfig",
);
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