RepoMirrors
/
haproxy
mirror of http://git.haproxy.org/git/haproxy.git/
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
haproxy/include/proto/dns.h

49 lines
1.9 KiB
C
Raw Normal View History

MEDIUM: dns: implement a DNS resolver Implementation of a DNS client in HAProxy to perform name resolution to IP addresses. It relies on the freshly created UDP client to perform the DNS resolution. For now, all UDP socket calls are performed in the DNS layer, but this might change later when the protocols are extended to be more suited to datagram mode. A new section called 'resolvers' is introduced thanks to this patch. It is used to describe DNS servers IP address and also many parameters.
2015-04-13 21:40:55 +00:00
/*
* include/proto/dns.h
* This file provides functions related to DNS protocol
*
* Copyright (C) 2014 Baptiste Assmann <bedis9@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_DNS_H
#define _PROTO_DNS_H
#include <types/dns.h>
MAJOR: dns: Refactor the DNS code This is a huge patch with many changes, all about the DNS. Initially, the idea was to update the DNS part to ease the threads support integration. But quickly, I started to refactor some parts. And after several iterations, it was impossible for me to commit the different parts atomically. So, instead of adding tens of patches, often reworking the same parts, it was easier to merge all my changes in a uniq patch. Here are all changes made on the DNS. First, the DNS initialization has been refactored. The DNS configuration parsing remains untouched, in cfgparse.c. But all checks have been moved in a post-check callback. In the function dns_finalize_config, for each resolvers, the nameservers configuration is tested and the task used to manage DNS resolutions is created. The links between the backend's servers and the resolvers are also created at this step. Here no connection are kept alive. So there is no needs anymore to reopen them after HAProxy fork. Connections used to send DNS queries will be opened on demand. Then, the way DNS requesters are linked to a DNS resolution has been reworked. The resolution used by a requester is now referenced into the dns_requester structure and the resolution pointers in server and dns_srvrq structures have been removed. wait and curr list of requesters, for a DNS resolution, have been replaced by a uniq list. And Finally, the way a requester is removed from a DNS resolution has been simplified. Now everything is done in dns_unlink_resolution. srv_set_fqdn function has been simplified. Now, there is only 1 way to set the server's FQDN, independently it is done by the CLI or when a SRV record is resolved. The static DNS resolutions pool has been replaced by a dynamoc pool. The part has been modified by Baptiste Assmann. The way the DNS resolutions are triggered by the task or by a health-check has been totally refactored. Now, all timeouts are respected. Especially hold.valid. The default frequency to wake up a resolvers is now configurable using "timeout resolve" parameter. Now, as documented, as long as invalid repsonses are received, we really wait all name servers responses before retrying. As far as possible, resources allocated during DNS configuration parsing are releases when HAProxy is shutdown. Beside all these changes, the code has been cleaned to ease code review and the doc has been updated.
2017-09-27 09:00:59 +00:00
extern struct list dns_resolvers;
struct dns_resolvers *find_resolvers_by_id(const char *id);
struct dns_srvrq *find_srvrq_by_name(const char *name, struct proxy *px);
struct dns_srvrq *new_dns_srvrq(struct server *srv, char *fqdn);
int dns_str_to_dn_label(const char *str, int str_len, char *dn, int dn_len);
int dns_dn_label_to_str(const char *dn, int dn_len, char *str, int str_len);
MEDIUM: dns: implement a DNS resolver Implementation of a DNS client in HAProxy to perform name resolution to IP addresses. It relies on the freshly created UDP client to perform the DNS resolution. For now, all UDP socket calls are performed in the DNS layer, but this might change later when the protocols are extended to be more suited to datagram mode. A new section called 'resolvers' is introduced thanks to this patch. It is used to describe DNS servers IP address and also many parameters.
2015-04-13 21:40:55 +00:00
int dns_hostname_validation(const char *string, char **err);
MINOR: dns: new snr_check_ip_callback function In the process of breaking links between dns_* functions and other structures (mainly server and a bit of resolution), the function dns_get_ip_from_response needs to be reworked: it now can call "callback" functions based on resolution's owner type to allow modifying the way the response is processed. For now, main purpose of the callback function is to check that an IP address is not already affected to an element of the same type. For now, only server type has a callback.
2017-05-03 13:43:12 +00:00
int dns_get_ip_from_response(struct dns_response_packet *dns_p,
REORG: dns: dns_option structure, storage of hostname_dn This patch introduces a some re-organisation around the DNS code in HAProxy. 1. make the dns_* functions less dependent on 'struct server' and 'struct resolution'. With this in mind, the following changes were performed: - 'struct dns_options' has been removed from 'struct resolution' (well, we might need it back at some point later, we'll see) ==> we'll use the 'struct dns_options' from the owner of the resolution - dns_get_ip_from_response(): takes a 'struct dns_options' instead of 'struct resolution' ==> so the caller can pass its own dns options to get the most appropriate IP from the response - dns_process_resolve(): struct dns_option is deduced from new resolution->requester_type parameter 2. add hostname_dn and hostname_dn_len into struct server In order to avoid recomputing a server's hostname into its domain name format (and use a trash buffer to store the result), it is safer to compute it once at configuration parsing and to store it into the struct server. In the mean time, the struct resolution linked to the server doesn't need anymore to store the hostname in domain name format. A simple pointer to the server one will make the trick. The function srv_alloc_dns_resolution() properly manages everything for us: memory allocation, pointer updates, etc... 3. move resolvers pointer into struct server This patch makes the pointer to struct dns_resolvers from struct dns_resolution obsolete. Purpose is to make the resolution as "neutral" as possible and since the requester is already linked to the resolvers, then we don't need this information anymore in the resolution itself.
2017-05-03 10:12:02 +00:00
struct dns_options *dns_opts, void *currentip,
MEDIUM: dns: extract options DNS selection preferences are actually declared inline in the struct server. There are copied from the server struct to the dns_resolution struct for each resolution. Next patchs adds new preferences options, and it is not a good way to copy all the configuration information before each dns resolution. This patch extract the configuration preference from the struct server and declares a new dedicated struct. Only a pointer to this new striuict will be copied before each dns resolution.
2016-02-17 20:25:09 +00:00
short currentip_sin_family,
MINOR: dns: new snr_check_ip_callback function In the process of breaking links between dns_* functions and other structures (mainly server and a bit of resolution), the function dns_get_ip_from_response needs to be reworked: it now can call "callback" functions based on resolution's owner type to allow modifying the way the response is processed. For now, main purpose of the callback function is to check that an IP address is not already affected to an element of the same type. For now, only server type has a callback.
2017-05-03 13:43:12 +00:00
void **newip, short *newip_sin_family,
void *owner);
MAJOR/REORG: dns: DNS resolution task and requester queues This patch is a major upgrade of the internal run-time DNS resolver in HAProxy and it brings the following 2 main changes: 1. DNS resolution task Up to now, DNS resolution was triggered by the health check task. From now, DNS resolution task is autonomous. It is started by HAProxy right after the scheduler is available and it is woken either when a network IO occurs for one of its nameserver or when a timeout is matched. From now, this means we can enable DNS resolution for a server without enabling health checking. 2. Introduction of a dns_requester structure Up to now, DNS resolution was purposely made for resolving server hostnames. The idea, is to ensure that any HAProxy internal object should be able to trigger a DNS resolution. For this purpose, 2 things has to be done: - clean up the DNS code from the server structure (this was already quite clean actually) and clean up the server's callbacks from manipulating too much DNS resolution - create an agnostic structure which allows linking a DNS resolution and a requester of any type (using obj_type enum) 3. Manage requesters through queues Up to now, there was an uniq relationship between a resolution and it's owner (aka the requester now). It's a shame, because in some cases, multiple objects may share the same hostname and may benefit from a resolution being performed by a third party. This patch introduces the notion of queues, which are basically lists of either currently running resolution or waiting ones. The resolutions are now available as a pool, which belongs to the resolvers. The pool has has a default size of 64 resolutions per resolvers and is allocated at configuration parsing.
2017-05-22 13:17:15 +00:00
BUG/MINOR: dns: Don't try to get the server lock if it's already held. dns_link_resolution() can be called with the server lock already held, so don't attempt to lock it again in that case.
2017-11-06 14:15:04 +00:00
int dns_link_resolution(void *requester, int requester_type, int requester_locked);
MAJOR: dns: Refactor the DNS code This is a huge patch with many changes, all about the DNS. Initially, the idea was to update the DNS part to ease the threads support integration. But quickly, I started to refactor some parts. And after several iterations, it was impossible for me to commit the different parts atomically. So, instead of adding tens of patches, often reworking the same parts, it was easier to merge all my changes in a uniq patch. Here are all changes made on the DNS. First, the DNS initialization has been refactored. The DNS configuration parsing remains untouched, in cfgparse.c. But all checks have been moved in a post-check callback. In the function dns_finalize_config, for each resolvers, the nameservers configuration is tested and the task used to manage DNS resolutions is created. The links between the backend's servers and the resolvers are also created at this step. Here no connection are kept alive. So there is no needs anymore to reopen them after HAProxy fork. Connections used to send DNS queries will be opened on demand. Then, the way DNS requesters are linked to a DNS resolution has been reworked. The resolution used by a requester is now referenced into the dns_requester structure and the resolution pointers in server and dns_srvrq structures have been removed. wait and curr list of requesters, for a DNS resolution, have been replaced by a uniq list. And Finally, the way a requester is removed from a DNS resolution has been simplified. Now everything is done in dns_unlink_resolution. srv_set_fqdn function has been simplified. Now, there is only 1 way to set the server's FQDN, independently it is done by the CLI or when a SRV record is resolved. The static DNS resolutions pool has been replaced by a dynamoc pool. The part has been modified by Baptiste Assmann. The way the DNS resolutions are triggered by the task or by a health-check has been totally refactored. Now, all timeouts are respected. Especially hold.valid. The default frequency to wake up a resolvers is now configurable using "timeout resolve" parameter. Now, as documented, as long as invalid repsonses are received, we really wait all name servers responses before retrying. As far as possible, resources allocated during DNS configuration parsing are releases when HAProxy is shutdown. Beside all these changes, the code has been cleaned to ease code review and the doc has been updated.
2017-09-27 09:00:59 +00:00
void dns_unlink_resolution(struct dns_requester *requester);
void dns_trigger_resolution(struct dns_requester *requester);
MAJOR/REORG: dns: DNS resolution task and requester queues This patch is a major upgrade of the internal run-time DNS resolver in HAProxy and it brings the following 2 main changes: 1. DNS resolution task Up to now, DNS resolution was triggered by the health check task. From now, DNS resolution task is autonomous. It is started by HAProxy right after the scheduler is available and it is woken either when a network IO occurs for one of its nameserver or when a timeout is matched. From now, this means we can enable DNS resolution for a server without enabling health checking. 2. Introduction of a dns_requester structure Up to now, DNS resolution was purposely made for resolving server hostnames. The idea, is to ensure that any HAProxy internal object should be able to trigger a DNS resolution. For this purpose, 2 things has to be done: - clean up the DNS code from the server structure (this was already quite clean actually) and clean up the server's callbacks from manipulating too much DNS resolution - create an agnostic structure which allows linking a DNS resolution and a requester of any type (using obj_type enum) 3. Manage requesters through queues Up to now, there was an uniq relationship between a resolution and it's owner (aka the requester now). It's a shame, because in some cases, multiple objects may share the same hostname and may benefit from a resolution being performed by a third party. This patch introduces the notion of queues, which are basically lists of either currently running resolution or waiting ones. The resolutions are now available as a pool, which belongs to the resolvers. The pool has has a default size of 64 resolutions per resolvers and is allocated at configuration parsing.
2017-05-22 13:17:15 +00:00
MEDIUM: dns: implement a DNS resolver Implementation of a DNS client in HAProxy to perform name resolution to IP addresses. It relies on the freshly created UDP client to perform the DNS resolution. For now, all UDP socket calls are performed in the DNS layer, but this might change later when the protocols are extended to be more suited to datagram mode. A new section called 'resolvers' is introduced thanks to this patch. It is used to describe DNS servers IP address and also many parameters.
2015-04-13 21:40:55 +00:00
#endif // _PROTO_DNS_H