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