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363 lines
16 KiB
363 lines
16 KiB
5 months ago
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/*
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* include/haproxy/dns-t.h
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* This file provides structures and types for DNS.
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*
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* Copyright (C) 2014 Baptiste Assmann <bedis9@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _HAPROXY_DNS_T_H
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#define _HAPROXY_DNS_T_H
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#include <import/eb32tree.h>
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#include <haproxy/connection-t.h>
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#include <haproxy/dgram-t.h>
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#include <haproxy/obj_type-t.h>
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#include <haproxy/stats-t.h>
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#include <haproxy/task-t.h>
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#include <haproxy/thread.h>
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extern struct pool_head *dns_requester_pool;
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/*DNS maximum values */
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/*
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* Maximum issued from RFC:
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* RFC 1035: https://www.ietf.org/rfc/rfc1035.txt chapter 2.3.4
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* RFC 2671: http://tools.ietf.org/html/rfc2671
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*/
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#define DNS_MAX_LABEL_SIZE 63
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#define DNS_MAX_NAME_SIZE 255
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#define DNS_MAX_UDP_MESSAGE 8192
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/* DNS minimum record size: 1 char + 1 NULL + type + class */
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#define DNS_MIN_RECORD_SIZE (1 + 1 + 2 + 2)
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/* DNS smallest fqdn 'a.gl' size */
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# define DNS_SMALLEST_FQDN_SIZE 4
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/* maximum number of query records in a DNS response
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* For now, we allow only one */
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#define DNS_MAX_QUERY_RECORDS 1
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/* maximum number of answer record in a DNS response */
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#define DNS_MAX_ANSWER_RECORDS ((DNS_MAX_UDP_MESSAGE - DNS_HEADER_SIZE) / DNS_MIN_RECORD_SIZE)
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/* size of dns_buffer used to store responses from the buffer
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* dns_buffer is used to store data collected from records found in a response.
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* Before using it, caller will always check that there is at least DNS_MAX_NAME_SIZE bytes
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* available */
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#define DNS_ANALYZE_BUFFER_SIZE DNS_MAX_UDP_MESSAGE + DNS_MAX_NAME_SIZE
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/* DNS error messages */
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#define DNS_TOO_LONG_FQDN "hostname too long"
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#define DNS_LABEL_TOO_LONG "one label too long"
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#define DNS_INVALID_CHARACTER "found an invalid character"
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/* dns query class */
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#define DNS_RCLASS_IN 1 /* internet class */
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/* dns record types (non exhaustive list) */
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#define DNS_RTYPE_A 1 /* IPv4 address */
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#define DNS_RTYPE_CNAME 5 /* canonical name */
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#define DNS_RTYPE_AAAA 28 /* IPv6 address */
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#define DNS_RTYPE_SRV 33 /* SRV record */
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#define DNS_RTYPE_OPT 41 /* OPT */
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#define DNS_RTYPE_ANY 255 /* all records */
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/* dns rcode values */
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#define DNS_RCODE_NO_ERROR 0 /* no error */
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#define DNS_RCODE_NX_DOMAIN 3 /* non existent domain */
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#define DNS_RCODE_REFUSED 5 /* query refused */
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/* dns flags masks */
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#define DNS_FLAG_TRUNCATED 0x0200 /* mask for truncated flag */
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#define DNS_FLAG_REPLYCODE 0x000F /* mask for reply code */
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/* max number of network preference entries are available from the
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* configuration file.
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*/
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#define SRV_MAX_PREF_NET 5
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/* DNS header size */
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#define DNS_HEADER_SIZE ((int)sizeof(struct dns_header))
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/* DNS request or response header structure */
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struct dns_header {
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uint16_t id;
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uint16_t flags;
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uint16_t qdcount;
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uint16_t ancount;
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uint16_t nscount;
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uint16_t arcount;
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} __attribute__ ((packed));
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/* short structure to describe a DNS question */
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/* NOTE: big endian structure */
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struct dns_question {
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unsigned short qtype; /* question type */
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unsigned short qclass; /* query class */
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};
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/* NOTE: big endian structure */
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struct dns_query_item {
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char name[DNS_MAX_NAME_SIZE+1]; /* query name */
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unsigned short type; /* question type */
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unsigned short class; /* query class */
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struct list list;
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};
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/* NOTE: big endian structure */
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struct dns_additional_record {
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uint8_t name; /* domain name, must be 0 (RFC 6891) */
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uint16_t type; /* record type DNS_RTYPE_OPT (41) */
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uint16_t udp_payload_size; /* maximum size accepted for the response */
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uint32_t extension; /* extended rcode and flags, not used for now */
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uint16_t data_length; /* data length */
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/* as of today, we don't support yet edns options, that said I already put a
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* placeholder here for this purpose. We may need to define a dns_option_record
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* structure which itself should point to different type of data, based on the
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* extension set (client subnet, tcp keepalive, etc...)*/
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// struct list options; /* list of option records */
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} __attribute__ ((packed));
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/* NOTE: big endian structure */
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struct dns_answer_item {
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/*For SRV type, name also includes service and protocol value */
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char name[DNS_MAX_NAME_SIZE+1]; /* answer name */
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int16_t type; /* question type */
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int16_t class; /* query class */
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int32_t ttl; /* response TTL */
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int16_t priority; /* SRV type priority */
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uint16_t weight; /* SRV type weight */
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uint16_t port; /* SRV type port */
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uint16_t data_len; /* number of bytes in target below */
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struct sockaddr address; /* IPv4 or IPv6, network format */
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char target[DNS_MAX_NAME_SIZE+1]; /* Response data: SRV or CNAME type target */
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time_t last_seen; /* When was the answer was last seen */
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struct dns_answer_item *ar_item; /* pointer to a RRset from the additional section, if exists */
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struct list list;
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};
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struct dns_response_packet {
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struct dns_header header;
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struct list query_list;
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struct list answer_list;
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/* authority ignored for now */
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};
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/* Resolvers section and parameters. It is linked to the name servers
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* servers points to it.
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* current resolution are stored in a FIFO list.
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*/
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struct dns_resolvers {
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__decl_thread(HA_SPINLOCK_T lock);
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unsigned int accepted_payload_size; /* maximum payload size we accept for responses */
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int nb_nameservers; /* total number of active nameservers in a resolvers section */
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int resolve_retries; /* number of retries before giving up */
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struct { /* time to: */
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int resolve; /* wait between 2 queries for the same resolution */
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int retry; /* wait for a response before retrying */
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} timeout;
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struct { /* time to hold current data when */
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int valid; /* a response is valid */
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int nx; /* a response doesn't exist */
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int timeout; /* no answer was delivered */
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int refused; /* dns server refused to answer */
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int other; /* other dns response errors */
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int obsolete; /* an answer hasn't been seen */
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} hold;
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struct task *t; /* timeout management */
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struct {
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struct list wait; /* resolutions managed to this resolvers section */
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struct list curr; /* current running resolutions */
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} resolutions;
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struct eb_root query_ids; /* tree to quickly lookup/retrieve query ids currently in use
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* used by each nameserver, but stored in resolvers since there must
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* be a unique relation between an eb_root and an eb_node (resolution) */
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struct list list; /* resolvers list */
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struct list nameservers; /* dns server list */
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char *id; /* resolvers unique identifier */
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struct {
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const char *file; /* file where the section appears */
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int line; /* line where the section appears */
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} conf; /* config information */
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};
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/* Structure describing a name server used during name resolution.
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* A name server belongs to a resolvers section.
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*/
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struct dns_nameserver {
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char *id; /* nameserver unique identifier */
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struct {
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const char *file; /* file where the section appears */
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int line; /* line where the section appears */
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} conf; /* config information */
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struct dns_resolvers *resolvers;
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struct dgram_conn *dgram; /* transport layer */
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struct sockaddr_storage addr; /* IP address */
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EXTRA_COUNTERS(extra_counters);
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struct dns_counters *counters;
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struct list list; /* nameserver chained list */
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};
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struct dns_counters {
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char *id;
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long long sent; /* - queries sent */
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long long snd_error; /* - sending errors */
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long long valid; /* - valid response */
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long long update; /* - valid response used to update server's IP */
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long long cname; /* - CNAME response requiring new resolution */
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long long cname_error; /* - error when resolving CNAMEs */
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long long any_err; /* - void response (usually because ANY qtype) */
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long long nx; /* - NX response */
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long long timeout; /* - queries which reached timeout */
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long long refused; /* - queries refused */
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long long other; /* - other type of response */
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long long invalid; /* - malformed DNS response */
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long long too_big; /* - too big response */
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long long outdated; /* - outdated response (server slower than the other ones) */
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long long truncated; /* - truncated response */;
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};
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struct dns_options {
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int family_prio; /* which IP family should the resolver use when both are returned */
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struct {
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int family;
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union {
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struct in_addr in4;
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struct in6_addr in6;
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} addr;
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union {
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struct in_addr in4;
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struct in6_addr in6;
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} mask;
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} pref_net[SRV_MAX_PREF_NET];
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int pref_net_nb; /* The number of registered preferred networks. */
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int accept_duplicate_ip; /* flag to indicate whether the associated object can use an IP address
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already set to an other object of the same group */
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int ignore_weight; /* flag to indicate whether to ignore the weight within the record */
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};
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/* Resolution structure associated to single server and used to manage name
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* resolution for this server.
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* The only link between the resolution and a nameserver is through the
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* query_id.
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*/
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struct dns_resolution {
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struct dns_resolvers *resolvers; /* pointer to the resolvers structure owning the resolution */
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struct list requesters; /* list of requesters using this resolution */
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int uuid; /* unique id (used for debugging purpose) */
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char *hostname_dn; /* server hostname in domain name label format */
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int hostname_dn_len; /* server domain name label len */
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unsigned int last_resolution; /* time of the last resolution */
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unsigned int last_query; /* time of the last query sent */
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unsigned int last_valid; /* time of the last valid response */
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int query_id; /* DNS query ID dedicated for this resolution */
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struct eb32_node qid; /* ebtree query id */
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int prefered_query_type; /* preferred query type */
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int query_type; /* current query type */
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int status; /* status of the resolution being processed RSLV_STATUS_* */
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int step; /* RSLV_STEP_* */
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int try; /* current resolution try */
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int nb_queries; /* count number of queries sent */
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int nb_responses; /* count number of responses received */
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struct dns_response_packet response; /* structure hosting the DNS response */
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struct dns_query_item response_query_records[DNS_MAX_QUERY_RECORDS]; /* <response> query records */
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struct list list; /* resolution list */
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};
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/* Structure used to describe the owner of a DNS resolution. */
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struct dns_requester {
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enum obj_type *owner; /* pointer to the owner (server or dns_srvrq) */
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struct dns_resolution *resolution; /* pointer to the owned DNS resolution */
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int (*requester_cb)(struct dns_requester *, struct dns_nameserver *); /* requester callback for valid response */
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int (*requester_error_cb)(struct dns_requester *, int); /* requester callback, for error management */
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struct list list; /* requester list */
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};
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/* Last resolution status code */
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enum {
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RSLV_STATUS_NONE = 0, /* no resolution occurred yet */
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RSLV_STATUS_VALID, /* no error */
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RSLV_STATUS_INVALID, /* invalid responses */
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RSLV_STATUS_ERROR, /* error */
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RSLV_STATUS_NX, /* NXDOMAIN */
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RSLV_STATUS_REFUSED, /* server refused our query */
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RSLV_STATUS_TIMEOUT, /* no response from DNS servers */
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RSLV_STATUS_OTHER, /* other errors */
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};
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/* Current resolution step */
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enum {
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RSLV_STEP_NONE = 0, /* nothing happening currently */
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RSLV_STEP_RUNNING, /* resolution is running */
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};
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/* Return codes after analyzing a DNS response */
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enum {
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DNS_RESP_VALID = 0, /* valid response */
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DNS_RESP_INVALID, /* invalid response (various type of errors can trigger it) */
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DNS_RESP_ERROR, /* DNS error code */
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DNS_RESP_NX_DOMAIN, /* resolution unsuccessful */
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DNS_RESP_REFUSED, /* DNS server refused to answer */
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DNS_RESP_ANCOUNT_ZERO, /* no answers in the response */
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DNS_RESP_WRONG_NAME, /* response does not match query name */
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DNS_RESP_CNAME_ERROR, /* error when resolving a CNAME in an atomic response */
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DNS_RESP_TIMEOUT, /* DNS server has not answered in time */
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DNS_RESP_TRUNCATED, /* DNS response is truncated */
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DNS_RESP_NO_EXPECTED_RECORD, /* No expected records were found in the response */
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DNS_RESP_QUERY_COUNT_ERROR, /* we did not get the expected number of queries in the response */
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DNS_RESP_INTERNAL, /* internal resolver error */
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};
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/* Return codes after searching an IP in a DNS response buffer, using a family
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* preference
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*/
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enum {
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DNS_UPD_NO = 1, /* provided IP was found and preference is matched
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* OR provided IP found and preference is not matched, but no IP
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* matching preference was found */
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DNS_UPD_SRVIP_NOT_FOUND, /* provided IP not found
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* OR provided IP found and preference is not match and an IP
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* matching preference was found */
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|
DNS_UPD_CNAME, /* CNAME without any IP provided in the response */
|
||
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|
DNS_UPD_NAME_ERROR, /* name in the response did not match the query */
|
||
|
|
DNS_UPD_NO_IP_FOUND, /* no IP could be found in the response */
|
||
|
|
DNS_UPD_OBSOLETE_IP, /* The server IP was obsolete, and no other IP was found */
|
||
|
|
};
|
||
|
|
|
||
|
|
struct proxy;
|
||
|
|
struct dns_srvrq {
|
||
|
|
enum obj_type obj_type; /* object type == OBJ_TYPE_SRVRQ */
|
||
|
|
struct dns_resolvers *resolvers; /* pointer to the resolvers structure used for this server template */
|
||
|
|
struct proxy *proxy; /* associated proxy */
|
||
|
|
char *name;
|
||
|
|
char *hostname_dn; /* server hostname in Domain Name format */
|
||
|
|
int hostname_dn_len; /* string length of the server hostname in Domain Name format */
|
||
|
|
struct dns_requester *dns_requester; /* used to link to its DNS resolution */
|
||
|
|
struct list list; /* Next SRV RQ for the same proxy */
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif /* _HAPROXY_DNS_T_H */
|