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Diffstat (limited to 'include/haproxy/resolvers-t.h')
| -rw-r--r-- | include/haproxy/resolvers-t.h | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/include/haproxy/resolvers-t.h b/include/haproxy/resolvers-t.h new file mode 100644 index 0000000..b727463 --- /dev/null +++ b/include/haproxy/resolvers-t.h @@ -0,0 +1,297 @@ +/* + * include/haproxy/dns-t.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 _HAPROXY_RESOLVERS_T_H +#define _HAPROXY_RESOLVERS_T_H + +#include <import/ebtree-t.h> + +#include <haproxy/connection-t.h> +#include <haproxy/dns-t.h> +#include <haproxy/obj_type-t.h> +#include <haproxy/stats-t.h> +#include <haproxy/task-t.h> +#include <haproxy/thread.h> + +extern struct pool_head *resolv_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 65535 + +/* 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 + +/* NOTE: big endian structure */ +struct resolv_query_item { + char name[DNS_MAX_NAME_SIZE+1]; /* query name */ + unsigned short type; /* question type */ + unsigned short class; /* query class */ +}; + +/* NOTE: big endian structure */ +struct resolv_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 the <data> field below */ + struct eb32_node link; /* linking node */ + union { + struct sockaddr_in in4; /* IPv4 address for RTYPE_A */ + struct sockaddr_in6 in6; /* IPv6 address for RTYPE_AAAA */ + char target[DNS_MAX_NAME_SIZE+1]; /* Response data: SRV or CNAME type target */ + } data; + unsigned int last_seen; /* When was the answer was last seen */ + struct resolv_answer_item *ar_item; /* pointer to a RRset from the additional section, if exists */ + struct list attached_servers; /* attached server head */ +}; + +struct resolv_response { + struct dns_header header; + struct eb_root answer_tree; + /* 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 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 */ + struct proxy *px; /* px to handle connections to DNS servers */ + char *id; /* resolvers unique identifier */ + struct { + const char *file; /* file where the section appears */ + int line; /* line where the section appears */ + int implicit; /* config was auto-generated and must be silent */ + } conf; /* config information */ +}; + +struct resolv_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 resolv_resolution { + struct 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 resolv_response response; /* structure hosting the DNS response */ + struct resolv_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 resolv_requester { + enum obj_type *owner; /* pointer to the owner (server or dns_srvrq) */ + struct resolv_resolution *resolution; /* pointer to the owned DNS resolution */ + + int (*requester_cb)(struct resolv_requester *, struct dns_counters *); /* requester callback for valid response */ + int (*requester_error_cb)(struct resolv_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 { + RSLV_RESP_VALID = 0, /* valid response */ + RSLV_RESP_INVALID, /* invalid response (various type of errors can trigger it) */ + RSLV_RESP_ERROR, /* DNS error code */ + RSLV_RESP_NX_DOMAIN, /* resolution unsuccessful */ + RSLV_RESP_REFUSED, /* DNS server refused to answer */ + RSLV_RESP_ANCOUNT_ZERO, /* no answers in the response */ + RSLV_RESP_WRONG_NAME, /* response does not match query name */ + RSLV_RESP_CNAME_ERROR, /* error when resolving a CNAME in an atomic response */ + RSLV_RESP_TIMEOUT, /* DNS server has not answered in time */ + RSLV_RESP_TRUNCATED, /* DNS response is truncated */ + RSLV_RESP_NO_EXPECTED_RECORD, /* No expected records were found in the response */ + RSLV_RESP_QUERY_COUNT_ERROR, /* we did not get the expected number of queries in the response */ + RSLV_RESP_INTERNAL, /* internal resolver error */ +}; + +/* Return codes after searching an IP in a DNS response buffer, using a family + * preference + */ +enum { + RSLV_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. + */ + RSLV_UPD_SRVIP_NOT_FOUND, /* provided IP not found + * OR provided IP found and preference is not match and an IP + * matching preference was found. + */ + RSLV_UPD_CNAME, /* CNAME without any IP provided in the response */ + RSLV_UPD_NAME_ERROR, /* name in the response did not match the query */ + RSLV_UPD_NO_IP_FOUND, /* no IP could be found in the response */ + RSLV_UPD_OBSOLETE_IP, /* The server IP was obsolete, and no other IP was found */ +}; + +struct proxy; +struct resolv_srvrq { + enum obj_type obj_type; /* object type == OBJ_TYPE_SRVRQ */ + struct 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 resolv_requester *requester; /* used to link to its DNS resolution */ + struct list attached_servers; /* List of the servers free to use */ + struct eb_root named_servers; /* tree of servers indexed by hostnames found in server state file */ + struct list list; /* Next SRV RQ for the same proxy */ +}; + +#endif /* _HAPROXY_RESOLVERS_T_H */ |