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			141 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			141 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Asterisk -- An open source telephony toolkit.
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|  *
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|  * Copyright (C) 1999 - 2005, Digium, Inc.
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|  *
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|  * 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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|  * See http://www.asterisk.org for more information about
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|  * the Asterisk project. Please do not directly contact
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|  * any of the maintainers of this project for assistance;
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|  * the project provides a web site, mailing lists and IRC
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|  * channels for your use.
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|  *
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|  * This program is free software, distributed under the terms of
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|  * the GNU General Public License Version 2. See the LICENSE file
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|  * at the top of the source tree.
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|  */
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| 
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| /*! \file
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|  *
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|  * \brief DNS SRV Record Lookup Support for Asterisk
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|  *
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|  * \author Mark Spencer <markster@digium.com>
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|  * 
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|  * \arg See also \ref AstENUM
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|  *
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|  * \note Funding provided by nic.at
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|  */
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| 
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| #include <sys/types.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 <stdio.h>
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| #include <string.h>
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| #include <unistd.h>
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| 
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| #include "asterisk.h"
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| 
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| ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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| 
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| #include "asterisk/channel.h"
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| #include "asterisk/logger.h"
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| #include "asterisk/srv.h"
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| #include "asterisk/dns.h"
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| #include "asterisk/options.h"
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| #include "asterisk/utils.h"
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| 
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| #ifdef __APPLE__
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| #undef T_SRV
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| #define T_SRV 33
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| #endif
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| 
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| struct srv {
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| 	unsigned short priority;
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| 	unsigned short weight;
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| 	unsigned short portnum;
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| } __attribute__ ((__packed__));
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| 
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| static int parse_srv(char *host, int hostlen, int *portno, char *answer, int len, char *msg)
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| {
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| 	int res = 0;
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| 	struct srv *srv = (struct srv *)answer;
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| 	char repl[256] = "";
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| 
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| 	if (len < sizeof(struct srv)) {
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| 		printf("Length too short\n");
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| 		return -1;
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| 	}
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| 	answer += sizeof(struct srv);
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| 	len -= sizeof(struct srv);
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| 
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| 	if ((res = dn_expand((unsigned char *)msg, (unsigned char *)answer + len, (unsigned char *)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 (res && strcmp(repl, ".")) {
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| 		if (option_verbose > 3)
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| 			ast_verbose( VERBOSE_PREFIX_3 "parse_srv: SRV mapped to host %s, port %d\n", repl, ntohs(srv->portnum));
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| 		if (host) {
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| 			ast_copy_string(host, repl, hostlen);
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| 			host[hostlen-1] = '\0';
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| 		}
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| 		if (portno)
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| 			*portno = ntohs(srv->portnum);
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| 		return 0;
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| 	}
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| 	return -1;
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| }
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| 
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| struct srv_context {
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| 	char *host;
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| 	int hostlen;
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| 	int *port;
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| };
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| 
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| static int srv_callback(void *context, char *answer, int len, char *fullanswer)
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| {
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| 	struct srv_context *c = (struct srv_context *)context;
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| 
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| 	if (parse_srv(c->host, c->hostlen, c->port, answer, len, fullanswer)) {
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| 		ast_log(LOG_WARNING, "Failed to parse srv\n");
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| 		return -1;
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| 	}
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| 
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| 	if (!ast_strlen_zero(c->host))
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| 		return 1;
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| 
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| 	return 0;
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| }
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| 
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| int ast_get_srv(struct ast_channel *chan, char *host, int hostlen, int *port, const char *service)
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| {
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| 	struct srv_context context;
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| 	int ret;
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| 
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| 	context.host = host;
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| 	context.hostlen = hostlen;
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| 	context.port = port;
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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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| 
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| 	ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback);
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| 
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| 	if (chan)
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| 		ret |= ast_autoservice_stop(chan);
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| 
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| 	if (ret <= 0) {
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| 		host[0] = '\0';
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| 		*port = -1;
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| 		return ret;
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| 	}
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| 	return ret;
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| }
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