git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6073 65c4cc65-6c06-0410-ace0-fbb531ad65f3
493 lines
12 KiB
C
Executable file
493 lines
12 KiB
C
Executable file
/*
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* ENUM Support for Asterisk
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*
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* Copyright (C) 2003-2005, Digium, inc
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*
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* Written by Mark Spencer <markster@digium.com>
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*
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* Funding provided by nic.at
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*
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* Distributed under the terms of the GNU GPL
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*
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#if __APPLE_CC__ >= 1495
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#include <arpa/nameser_compat.h>
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#endif
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#include <resolv.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <regex.h>
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#include <unistd.h>
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#include <errno.h>
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#include "asterisk/logger.h"
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#include "asterisk/options.h"
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#include "asterisk/enum.h"
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#include "asterisk/dns.h"
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#include "asterisk/channel.h"
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#include "asterisk/config.h"
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#include "asterisk/utils.h"
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#ifdef __APPLE__
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#undef T_NAPTR
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#define T_NAPTR 35
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#endif
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#ifdef __APPLE__
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#undef T_TXT
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#define T_TXT 16
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#endif
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/* The IETF Enum standard root, managed by the ITU */
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#define TOPLEV "e164.arpa."
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/* Linked list from config file */
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static struct enum_search {
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char toplev[80];
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struct enum_search *next;
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} *toplevs;
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static int enumver = 0;
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AST_MUTEX_DEFINE_STATIC(enumlock);
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struct naptr {
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unsigned short order;
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unsigned short pref;
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} __attribute__ ((__packed__));
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/*--- parse_ie: Parse NAPTR record information elements */
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static int parse_ie(unsigned char *data, int maxdatalen, unsigned char *src, int srclen)
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{
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int len, olen;
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len = olen = (int)src[0];
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src++;
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srclen--;
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if (len > srclen) {
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ast_log(LOG_WARNING, "Want %d, got %d\n", len, srclen);
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return -1;
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}
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if (len > maxdatalen)
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len = maxdatalen;
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memcpy(data, src, len);
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return olen + 1;
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}
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/*--- parse_naptr: Parse DNS NAPTR record used in ENUM ---*/
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static int parse_naptr(unsigned char *dst, int dstsize, char *tech, int techsize, unsigned char *answer, int len, char *naptrinput)
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{
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unsigned char *oanswer = answer;
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unsigned char flags[80] = "";
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unsigned char services[80] = "";
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unsigned char regexp[80] = "";
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unsigned char repl[80] = "";
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unsigned char temp[80] = "";
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unsigned char delim;
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unsigned char *delim2;
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unsigned char *pattern, *subst, *d;
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int res;
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int regexp_len, size, backref;
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int d_len = sizeof(temp) - 1;
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regex_t preg;
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regmatch_t pmatch[9];
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dst[0] = '\0';
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if (len < sizeof(struct naptr)) {
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ast_log(LOG_WARNING, "NAPTR record length too short\n");
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return -1;
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}
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answer += sizeof(struct naptr);
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len -= sizeof(struct naptr);
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if ((res = parse_ie(flags, sizeof(flags) - 1, answer, len)) < 0) {
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ast_log(LOG_WARNING, "Failed to get flags from NAPTR record\n");
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return -1;
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} else {
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answer += res;
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len -= res;
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}
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if ((res = parse_ie(services, sizeof(services) - 1, answer, len)) < 0) {
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ast_log(LOG_WARNING, "Failed to get services from NAPTR record\n");
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return -1;
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} else {
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answer += res;
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len -= res;
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}
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if ((res = parse_ie(regexp, sizeof(regexp) - 1, answer, len)) < 0) {
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ast_log(LOG_WARNING, "Failed to get regexp from NAPTR record\n");
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return -1;
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} else {
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answer += res;
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len -= res;
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}
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if ((res = dn_expand(oanswer,answer + len,answer, repl, sizeof(repl) - 1)) < 0) {
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ast_log(LOG_WARNING, "Failed to expand hostname\n");
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return -1;
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}
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if (option_debug > 2) /* Advanced NAPTR debugging */
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ast_log(LOG_DEBUG, "NAPTR input='%s', flags='%s', services='%s', regexp='%s', repl='%s'\n",
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naptrinput, flags, services, regexp, repl);
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if (tolower(flags[0]) != 'u') {
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ast_log(LOG_WARNING, "NAPTR Flag must be 'U' or 'u'.\n");
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return -1;
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}
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if ((!strncasecmp(services, "e2u+sip", 7)) ||
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(!strncasecmp(services, "sip+e2u", 7))) {
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ast_copy_string(tech, "sip", techsize);
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} else if ((!strncasecmp(services, "e2u+h323", 8)) ||
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(!strncasecmp(services, "h323+e2u", 8))) {
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ast_copy_string(tech, "h323", techsize);
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} else if ((!strncasecmp(services, "e2u+x-iax2", 10)) ||
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(!strncasecmp(services, "e2u+iax2", 8)) ||
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(!strncasecmp(services, "iax2+e2u", 8))) {
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ast_copy_string(tech, "iax2", techsize);
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} else if ((!strncasecmp(services, "e2u+x-iax", 9)) ||
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(!strncasecmp(services, "e2u+iax", 7)) ||
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(!strncasecmp(services, "iax+e2u", 7))) {
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ast_copy_string(tech, "iax", techsize);
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} else if ((!strncasecmp(services, "e2u+tel", 7)) ||
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(!strncasecmp(services, "tel+e2u", 7))) {
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ast_copy_string(tech, "tel", techsize);
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} else if (!strncasecmp(services, "e2u+voice:", 10)) {
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ast_copy_string(tech, services+10, techsize);
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} else {
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ast_log(LOG_DEBUG,
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"Services must be e2u+${tech}, ${tech}+e2u, or e2u+voice: where $tech is from (sip, h323, tel, iax, iax2). \n");
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return 0;
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}
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/* DEDBUGGING STUB
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ast_copy_string(regexp, "!^\\+43(.*)$!\\1@bla.fasel!", sizeof(regexp) - 1);
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*/
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regexp_len = strlen(regexp);
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if (regexp_len < 7) {
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ast_log(LOG_WARNING, "Regex too short to be meaningful.\n");
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return -1;
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}
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delim = regexp[0];
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delim2 = strchr(regexp + 1, delim);
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if ((delim2 == NULL) || (regexp[regexp_len-1] != delim)) {
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ast_log(LOG_WARNING, "Regex delimiter error (on \"%s\").\n",regexp);
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return -1;
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}
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pattern = regexp + 1;
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*delim2 = 0;
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subst = delim2 + 1;
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regexp[regexp_len-1] = 0;
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#if 0
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printf("Pattern: %s\n", pattern);
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printf("Subst: %s\n", subst);
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#endif
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/*
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* now do the regex wizardry.
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*/
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if (regcomp(&preg, pattern, REG_EXTENDED | REG_NEWLINE)) {
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ast_log(LOG_WARNING, "NAPTR Regex compilation error (regex = \"%s\").\n",regexp);
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return -1;
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}
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if (preg.re_nsub > 9) {
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ast_log(LOG_WARNING, "NAPTR Regex compilation error: too many subs.\n");
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regfree(&preg);
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return -1;
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}
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if (regexec(&preg, naptrinput, 9, pmatch, 0)) {
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ast_log(LOG_WARNING, "NAPTR Regex match failed.\n");
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regfree(&preg);
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return -1;
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}
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regfree(&preg);
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d = temp;
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d_len--;
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while( *subst && (d_len > 0) ) {
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if ((subst[0] == '\\') && isdigit(subst[1]) && (pmatch[subst[1]-'0'].rm_so != -1)) {
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backref = subst[1]-'0';
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size = pmatch[backref].rm_eo - pmatch[backref].rm_so;
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if (size > d_len) {
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ast_log(LOG_WARNING, "Not enough space during NAPTR regex substitution.\n");
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return -1;
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}
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memcpy(d, naptrinput + pmatch[backref].rm_so, size);
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d += size;
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d_len -= size;
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subst += 2;
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} else if (isprint(*subst)) {
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*d++ = *subst++;
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d_len--;
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} else {
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ast_log(LOG_WARNING, "Error during regex substitution.\n");
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return -1;
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}
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}
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*d = 0;
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ast_copy_string(dst, temp, dstsize);
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dst[dstsize - 1] = '\0';
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return 0;
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}
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struct enum_context {
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char *dst; /* Destination part of URL from ENUM */
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int dstlen; /* Length */
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char *tech; /* Technology (from URL scheme) */
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int techlen; /* Length */
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char *txt; /* TXT record in TXT lookup */
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int txtlen; /* Length */
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char *naptrinput; /* The number to lookup */
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};
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/*--- txt_callback: Callback for TXT record lookup */
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static int txt_callback(void *context, u_char *answer, int len, u_char *fullanswer)
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{
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struct enum_context *c = (struct enum_context *)context;
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#if 0
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printf("ENUMTXT Called\n");
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#endif
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if (answer == NULL) {
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c->txt = NULL;
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c->txtlen = 0;
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return 0;
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}
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/* skip over first byte, as for some reason it's a vertical tab character */
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answer += 1;
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len -= 1;
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/* answer is not null-terminated, but should be */
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/* this is safe to do, as answer has extra bytes on the end we can
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safely overwrite with a null */
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answer[len] = '\0';
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/* now increment len so that len includes the null, so that we can
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compare apples to apples */
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len +=1;
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/* finally, copy the answer into c->txt */
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ast_copy_string(c->txt, answer, len < c->txtlen ? len : (c->txtlen));
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/* just to be safe, let's make sure c->txt is null terminated */
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c->txt[(c->txtlen)-1] = '\0';
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return 1;
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}
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/*--- enum_callback: Callback from ENUM lookup function */
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static int enum_callback(void *context, u_char *answer, int len, u_char *fullanswer)
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{
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struct enum_context *c = (struct enum_context *)context;
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if (parse_naptr(c->dst, c->dstlen, c->tech, c->techlen, answer, len, c->naptrinput)) {
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ast_log(LOG_WARNING, "Failed to parse naptr :(\n");
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return -1;
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}
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if (!ast_strlen_zero(c->dst))
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return 1;
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return 0;
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}
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/*--- ast_get_enum: ENUM lookup */
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int ast_get_enum(struct ast_channel *chan, const char *number, char *dst, int dstlen, char *tech, int techlen)
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{
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struct enum_context context;
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char tmp[259 + 80];
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char naptrinput[80] = "+";
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int pos = strlen(number) - 1;
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int newpos = 0;
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int ret = -1;
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struct enum_search *s = NULL;
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int version = -1;
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strncat(naptrinput, number, sizeof(naptrinput) - 2);
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context.naptrinput = naptrinput; /* The number */
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context.dst = dst; /* Return string */
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context.dstlen = dstlen;
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context.tech = tech; /* Return string */
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context.techlen = techlen;
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if (pos > 128)
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pos = 128;
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while(pos >= 0) {
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tmp[newpos++] = number[pos--];
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tmp[newpos++] = '.';
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}
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if (chan && ast_autoservice_start(chan) < 0)
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return -1;
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for(;;) {
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ast_mutex_lock(&enumlock);
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if (version != enumver) {
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/* Ooh, a reload... */
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s = toplevs;
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version = enumver;
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} else {
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s = s->next;
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}
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if (s) {
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strncpy(tmp + newpos, s->toplev, sizeof(tmp) - newpos - 1);
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}
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ast_mutex_unlock(&enumlock);
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if (!s)
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break;
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ret = ast_search_dns(&context, tmp, C_IN, T_NAPTR, enum_callback);
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if (ret > 0)
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break;
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}
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if (ret < 0) {
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ast_log(LOG_DEBUG, "No such number found: %s (%s)\n", tmp, strerror(errno));
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ret = 0;
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}
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if (chan)
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ret |= ast_autoservice_stop(chan);
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return ret;
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}
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/*--- ast_get_txt: Get TXT record from DNS.
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Really has nothing to do with enum, but anyway...
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*/
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int ast_get_txt(struct ast_channel *chan, const char *number, char *dst, int dstlen, char *tech, int techlen, char *txt, int txtlen)
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{
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struct enum_context context;
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char tmp[259 + 80];
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char naptrinput[80] = "+";
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int pos = strlen(number) - 1;
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int newpos = 0;
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int ret = -1;
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struct enum_search *s = NULL;
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int version = -1;
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strncat(naptrinput, number, sizeof(naptrinput) - 2);
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context.naptrinput = naptrinput;
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context.dst = dst;
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context.dstlen = dstlen;
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context.tech = tech;
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context.techlen = techlen;
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context.txt = txt;
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context.txtlen = txtlen;
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if (pos > 128)
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pos = 128;
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while(pos >= 0) {
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tmp[newpos++] = number[pos--];
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tmp[newpos++] = '.';
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}
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if (chan && ast_autoservice_start(chan) < 0)
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return -1;
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for(;;) {
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ast_mutex_lock(&enumlock);
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if (version != enumver) {
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/* Ooh, a reload... */
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s = toplevs;
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version = enumver;
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} else {
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s = s->next;
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}
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if (s) {
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strncpy(tmp + newpos, s->toplev, sizeof(tmp) - newpos - 1);
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}
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ast_mutex_unlock(&enumlock);
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if (!s)
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break;
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ret = ast_search_dns(&context, tmp, C_IN, T_TXT, txt_callback);
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if (ret > 0)
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break;
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}
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if (ret < 0) {
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ast_log(LOG_DEBUG, "No such number found: %s (%s)\n", tmp, strerror(errno));
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ret = 0;
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}
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if (chan)
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ret |= ast_autoservice_stop(chan);
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return ret;
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}
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/*--- enum_newtoplev: Add enum tree to linked list ---*/
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static struct enum_search *enum_newtoplev(char *s)
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{
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struct enum_search *tmp;
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tmp = malloc(sizeof(struct enum_search));
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if (tmp) {
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memset(tmp, 0, sizeof(struct enum_search));
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ast_copy_string(tmp->toplev, s, sizeof(tmp->toplev));
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}
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return tmp;
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}
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/*--- ast_enum_init: Initialize the ENUM support subsystem */
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int ast_enum_init(void)
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{
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struct ast_config *cfg;
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struct enum_search *s, *sl;
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struct ast_variable *v;
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/* Destroy existing list */
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ast_mutex_lock(&enumlock);
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s = toplevs;
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while(s) {
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sl = s;
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s = s->next;
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free(sl);
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}
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toplevs = NULL;
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cfg = ast_config_load("enum.conf");
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if (cfg) {
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sl = NULL;
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v = ast_variable_browse(cfg, "general");
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while(v) {
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if (!strcasecmp(v->name, "search")) {
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s = enum_newtoplev(v->value);
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if (s) {
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if (sl)
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sl->next = s;
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else
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toplevs = s;
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sl = s;
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}
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}
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v = v->next;
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}
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ast_config_destroy(cfg);
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} else {
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toplevs = enum_newtoplev(TOPLEV);
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}
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enumver++;
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ast_mutex_unlock(&enumlock);
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return 0;
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}
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int ast_enum_reload(void)
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{
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return ast_enum_init();
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}
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