de57235ac6
Asterisk's dnsmgr currently takes a pointer to an ast_sockaddr and updates it anytime an address resolves to something different. There are a couple of issues with this. First, the ast_sockaddr is usually the address of an ast_sockaddr inside a refcounted struct and we never bump the refcount of those structs when using dnsmgr. This makes it possible that a refresh could happen after the destructor for that object is called (despite ast_dnsmgr_release being called in that destructor). Second, the module using dnsmgr cannot be aware of an address changing without polling for it in the code. If an action needs to be taken on address update (like re-linking a SIP peer in the peers_by_ip table), then polling for this change negates many of the benefits of having dnsmgr in the first place. This patch adds a function to the dnsmgr API that calls an update callback instead of blindly updating the address itself. It also moves calls to ast_dnsmgr_release outside of the destructor functions and into cleanup functions that are called when we no longer need the objects and increments the refcount of the objects using dnsmgr since those objects are stored on the ast_dnsmgr_entry struct. A helper function for returning the proper default SIP port (non-tls vs tls) is also added and used. This patch also incorporates changes from a patch posted by Timo Teräs to ASTERISK-19106 for related dnsmgr issues. (closes issue ASTERISK-19106) Review: https://reviewboard.asterisk.org/r/1691/ ........ Merged revisions 353371 from http://svn.asterisk.org/svn/asterisk/branches/1.8 ........ Merged revisions 353397 from http://svn.asterisk.org/svn/asterisk/branches/10 git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@353418 65c4cc65-6c06-0410-ace0-fbb531ad65f3
157 lines
5.5 KiB
C
157 lines
5.5 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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* Kevin P. Fleming <kpfleming@digium.com>
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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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* \brief Background DNS update manager
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*/
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#ifndef _ASTERISK_DNSMGR_H
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#define _ASTERISK_DNSMGR_H
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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#include "asterisk/netsock2.h"
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#include "asterisk/srv.h"
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/*!
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* \brief A DNS manager entry
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*
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* This is an opaque type.
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*/
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struct ast_dnsmgr_entry;
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typedef void (*dns_update_func)(struct ast_sockaddr *old_addr, struct ast_sockaddr *new_addr, void *data);
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/*!
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* \brief Allocate a new DNS manager entry
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*
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* \param name the hostname
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* \param result where the DNS manager should store the IP address as it refreshes it.
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* \param service
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*
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* \details
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* This function allocates a new DNS manager entry object, and fills it with the
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* provided hostname and IP address. This function does not force an initial lookup
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* of the IP address. So, generally, this should be used when the initial address
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* is already known.
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*
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* \return a DNS manager entry
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* \version 1.6.1 result changed from struct in_addr to struct sockaddr_in to store port number
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* \version 1.8.0 result changed from struct ast_sockaddr_in to ast_sockaddr for IPv6 support
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*/
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struct ast_dnsmgr_entry *ast_dnsmgr_get(const char *name, struct ast_sockaddr *result, const char *service);
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/*!
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* \brief Allocate a new DNS manager entry
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*
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* \param name the hostname
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* \param result where the DNS manager should store the IP address as it refreshes it.
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* \param service
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* \param family Address family to filter DNS addresses.
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*
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* \details
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* This function allocates a new DNS manager entry object, and fills it with the
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* provided hostname and IP address. This function does not force an initial lookup
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* of the IP address. So, generally, this should be used when the initial address
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* is already known.
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*
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* \return a DNS manager entry
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*/
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struct ast_dnsmgr_entry *ast_dnsmgr_get_family(const char *name, struct ast_sockaddr *result, const char *service, unsigned int family);
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/*!
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* \brief Free a DNS manager entry
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*
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* \param entry the DNS manager entry to free
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*
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* \return nothing
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*/
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void ast_dnsmgr_release(struct ast_dnsmgr_entry *entry);
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/*!
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* \brief Allocate and initialize a DNS manager entry
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*
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* \param name the hostname
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* \param result where to store the IP address as the DNS manager refreshes it.
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* The address family is used as an input parameter to filter the returned addresses.
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* If it is 0, both IPv4 and IPv6 addresses can be returned.
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* \param dnsmgr Where to store the allocate DNS manager entry
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* \param service
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*
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* \note
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* This function allocates a new DNS manager entry object, and fills it with
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* the provided hostname and IP address. This function _does_ force an initial
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* lookup, so it may block for some period of time.
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*
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* \retval 0 success
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* \retval non-zero failure
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* \version 1.6.1 result changed from struct in_addr to struct aockaddr_in to store port number
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*/
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int ast_dnsmgr_lookup(const char *name, struct ast_sockaddr *result, struct ast_dnsmgr_entry **dnsmgr, const char *service);
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/*!
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* \brief Allocate and initialize a DNS manager entry, with update callback
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*
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* \param name the hostname
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* \param result The addr which is intended to be updated in the update callback when DNS manager calls it on refresh.
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* The address family is used as an input parameter to filter the returned addresses.
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* If it is 0, both IPv4 and IPv6 addresses can be returned.
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* \param dnsmgr Where to store the allocate DNS manager entry
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* \param service
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* \param func The update callback function
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* The update callback will be called when DNS manager detects that an IP address has been changed.
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* Instead of updating the addr itself, DNS manager will call this callback function with the old
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* and new addresses. It is the responsibility of the callback to perform any updates
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* \param data A pointer to data that will be passed through to the callback function
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*
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* \note
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* This function allocates a new DNS manager entry object, and fills it with
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* the provided hostname and IP address. This function _does_ force an initial
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* lookup, so it may block for some period of time.
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*
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* \retval 0 success
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* \retval non-zero failure
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*/
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int ast_dnsmgr_lookup_cb(const char *name, struct ast_sockaddr *result, struct ast_dnsmgr_entry **dnsmgr, const char *service, dns_update_func func, void *data);
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/*!
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* \brief Force a refresh of a dnsmgr entry
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*
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* \retval non-zero if the result is different than the previous result
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* \retval zero if the result is the same as the previous result
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*/
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int ast_dnsmgr_refresh(struct ast_dnsmgr_entry *entry);
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/*!
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* \brief Check is see if a dnsmgr entry has changed
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*
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* \retval non-zero if the dnsmgr entry has changed since the last call to
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* this function
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* \retval zero if the dnsmgr entry has not changed since the last call to
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* this function
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*/
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int ast_dnsmgr_changed(struct ast_dnsmgr_entry *entry);
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#if defined(__cplusplus) || defined(c_plusplus)
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}
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#endif /* c_plusplus */
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#endif /* ASTERISK_DNSMGR_H */
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