This helps clean up the Asterisk CLI by converting the log message from verbose to debug git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@362043 65c4cc65-6c06-0410-ace0-fbb531ad65f3
333 lines
7.9 KiB
C
333 lines
7.9 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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/*! \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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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#ifdef __APPLE__
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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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#endif
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#include <resolv.h>
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#include "asterisk/channel.h"
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#include "asterisk/srv.h"
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#include "asterisk/dns.h"
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#include "asterisk/utils.h"
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#include "asterisk/linkedlists.h"
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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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struct srv_entry {
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unsigned short priority;
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unsigned short weight;
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unsigned short port;
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unsigned int weight_sum;
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AST_LIST_ENTRY(srv_entry) list;
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char host[1];
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};
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struct srv_context {
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unsigned int have_weights:1;
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struct srv_entry *prev;
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unsigned int num_records;
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AST_LIST_HEAD_NOLOCK(srv_entries, srv_entry) entries;
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};
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static int parse_srv(unsigned char *answer, int len, unsigned char *msg, struct srv_entry **result)
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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 port;
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} __attribute__((__packed__)) *srv = (struct srv *) answer;
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int res = 0;
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char repl[256] = "";
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struct srv_entry *entry;
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if (len < sizeof(*srv))
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return -1;
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answer += sizeof(*srv);
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len -= sizeof(*srv);
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if ((res = dn_expand(msg, 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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/* the magic value "." for the target domain means that this service
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is *NOT* available at the domain we searched */
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if (!strcmp(repl, "."))
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return -1;
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if (!(entry = ast_calloc(1, sizeof(*entry) + strlen(repl))))
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return -1;
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entry->priority = ntohs(srv->priority);
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entry->weight = ntohs(srv->weight);
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entry->port = ntohs(srv->port);
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strcpy(entry->host, repl);
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*result = entry;
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return 0;
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}
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static int srv_callback(void *context, unsigned char *answer, int len, unsigned char *fullanswer)
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{
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struct srv_context *c = (struct srv_context *) context;
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struct srv_entry *entry = NULL;
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struct srv_entry *current;
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if (parse_srv(answer, len, fullanswer, &entry))
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return -1;
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if (entry->weight)
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c->have_weights = 1;
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AST_LIST_TRAVERSE_SAFE_BEGIN(&c->entries, current, list) {
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/* insert this entry just before the first existing
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entry with a higher priority */
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if (current->priority <= entry->priority)
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continue;
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AST_LIST_INSERT_BEFORE_CURRENT(entry, list);
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entry = NULL;
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break;
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}
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AST_LIST_TRAVERSE_SAFE_END;
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/* if we didn't find a place to insert the entry before an existing
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entry, then just add it to the end */
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if (entry)
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AST_LIST_INSERT_TAIL(&c->entries, entry, list);
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return 0;
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}
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/* Do the bizarre SRV record weight-handling algorithm
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involving sorting and random number generation...
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See RFC 2782 if you want know why this code does this
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*/
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static void process_weights(struct srv_context *context)
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{
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struct srv_entry *current;
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struct srv_entries newlist = AST_LIST_HEAD_NOLOCK_INIT_VALUE;
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while (AST_LIST_FIRST(&context->entries)) {
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unsigned int random_weight;
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unsigned int weight_sum;
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unsigned short cur_priority = AST_LIST_FIRST(&context->entries)->priority;
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struct srv_entries temp_list = AST_LIST_HEAD_NOLOCK_INIT_VALUE;
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weight_sum = 0;
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AST_LIST_TRAVERSE_SAFE_BEGIN(&context->entries, current, list) {
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if (current->priority != cur_priority)
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break;
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AST_LIST_MOVE_CURRENT(&temp_list, list);
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}
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AST_LIST_TRAVERSE_SAFE_END;
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while (AST_LIST_FIRST(&temp_list)) {
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weight_sum = 0;
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AST_LIST_TRAVERSE(&temp_list, current, list)
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current->weight_sum = weight_sum += current->weight;
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/* if all the remaining entries have weight == 0,
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then just append them to the result list and quit */
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if (weight_sum == 0) {
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AST_LIST_APPEND_LIST(&newlist, &temp_list, list);
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break;
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}
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random_weight = 1 + (unsigned int) ((float) weight_sum * (ast_random() / ((float) RAND_MAX + 1.0)));
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AST_LIST_TRAVERSE_SAFE_BEGIN(&temp_list, current, list) {
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if (current->weight < random_weight)
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continue;
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AST_LIST_MOVE_CURRENT(&newlist, list);
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break;
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}
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AST_LIST_TRAVERSE_SAFE_END;
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}
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}
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/* now that the new list has been ordered,
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put it in place */
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AST_LIST_APPEND_LIST(&context->entries, &newlist, list);
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}
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int ast_srv_lookup(struct srv_context **context, const char *service, const char **host, unsigned short *port)
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{
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struct srv_entry *cur;
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if (*context == NULL) {
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if (!(*context = ast_calloc(1, sizeof(struct srv_context)))) {
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return -1;
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}
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AST_LIST_HEAD_INIT_NOLOCK(&(*context)->entries);
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if ((ast_search_dns(*context, service, C_IN, T_SRV, srv_callback)) < 0) {
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ast_free(*context);
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*context = NULL;
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return -1;
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}
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if ((*context)->have_weights) {
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process_weights(*context);
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}
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(*context)->prev = AST_LIST_FIRST(&(*context)->entries);
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*host = (*context)->prev->host;
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*port = (*context)->prev->port;
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AST_LIST_TRAVERSE(&(*context)->entries, cur, list) {
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++((*context)->num_records);
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}
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return 0;
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}
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if (((*context)->prev = AST_LIST_NEXT((*context)->prev, list))) {
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/* Retrieve next item in result */
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*host = (*context)->prev->host;
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*port = (*context)->prev->port;
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return 0;
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} else {
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/* No more results */
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while ((cur = AST_LIST_REMOVE_HEAD(&(*context)->entries, list))) {
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ast_free(cur);
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}
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ast_free(*context);
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*context = NULL;
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return 1;
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}
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}
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void ast_srv_cleanup(struct srv_context **context)
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{
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const char *host;
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unsigned short port;
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if (*context) {
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/* We have a context to clean up. */
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while (!(ast_srv_lookup(context, NULL, &host, &port))) {
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}
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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 = { .entries = AST_LIST_HEAD_NOLOCK_INIT_VALUE };
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struct srv_entry *current;
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int ret;
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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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if (context.have_weights) {
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process_weights(&context);
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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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/* TODO: there could be a "." entry in the returned list of
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answers... if so, this requires special handling */
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/* the list of entries will be sorted in the proper selection order
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already, so we just need the first one (if any) */
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if ((ret > 0) && (current = AST_LIST_REMOVE_HEAD(&context.entries, list))) {
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ast_copy_string(host, current->host, hostlen);
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*port = current->port;
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ast_free(current);
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ast_debug(4, "ast_get_srv: SRV lookup for '%s' mapped to host %s, port %d\n",
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service, host, *port);
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} else {
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host[0] = '\0';
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*port = -1;
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}
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while ((current = AST_LIST_REMOVE_HEAD(&context.entries, list))) {
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ast_free(current);
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}
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return ret;
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}
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unsigned int ast_srv_get_record_count(struct srv_context *context)
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{
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return context->num_records;
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}
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int ast_srv_get_nth_record(struct srv_context *context, int record_num, const char **host,
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unsigned short *port, unsigned short *priority, unsigned short *weight)
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{
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int i = 1;
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int res = -1;
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struct srv_entry *entry;
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if (record_num < 1 || record_num > context->num_records) {
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return res;
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}
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AST_LIST_TRAVERSE(&context->entries, entry, list) {
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if (i == record_num) {
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*host = entry->host;
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*port = entry->port;
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*priority = entry->priority;
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*weight = entry->weight;
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res = 0;
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break;
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}
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++i;
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}
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return res;
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}
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