| /* |
| * include/types/dns.h |
| * This file provides structures and types for DNS. |
| * |
| * 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 _TYPES_DNS_H |
| #define _TYPES_DNS_H |
| |
| #include <eb32tree.h> |
| |
| #include <common/mini-clist.h> |
| #include <common/hathreads.h> |
| |
| #include <types/connection.h> |
| #include <types/obj_type.h> |
| #include <types/proto_udp.h> |
| #include <types/proxy.h> |
| #include <types/server.h> |
| #include <types/task.h> |
| |
| 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 minimun 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 list list; |
| }; |
| |
| struct dns_response_packet { |
| struct dns_header header; |
| struct list query_list; |
| struct list answer_list; |
| /* authority and additional_information 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 { |
| char *id; /* resolvers unique identifier */ |
| struct { |
| const char *file; /* file where the section appears */ |
| int line; /* line where the section appears */ |
| } conf; /* config information */ |
| struct list nameservers; /* dns server list */ |
| 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) */ |
| __decl_hathreads(HA_SPINLOCK_T lock); |
| struct list list; /* resolvers list */ |
| }; |
| |
| /* 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 */ |
| |
| struct { /* numbers relted to this name server: */ |
| 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 */ |
| } counters; |
| struct list list; /* nameserver chained list */ |
| }; |
| |
| 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]; /* <response> 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 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 /* _TYPES_DNS_H */ |