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/*
* 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_DNS_T_H
#define _HAPROXY_DNS_T_H
#include <import/ebtree-t.h>
#include <haproxy/connection-t.h>
#include <haproxy/buf-t.h>
#include <haproxy/dgram-t.h>
#include <haproxy/dns_ring-t.h>
#include <haproxy/obj_type-t.h>
#include <haproxy/stats-t.h>
#include <haproxy/task-t.h>
#include <haproxy/thread.h>
/* DNS header size */
#define DNS_HEADER_SIZE ((int)sizeof(struct dns_header))
/* max pending requests per stream */
#define DNS_STREAM_MAX_PIPELINED_REQ 4
#define DNS_TCP_MSG_MAX_SIZE 65535
#define DNS_TCP_MSG_RING_MAX_SIZE (1 + 1 + 3 + DNS_TCP_MSG_MAX_SIZE) // varint_bytes(DNS_TCP_MSG_MAX_SIZE) == 3
/* threshold to consider that the link to dns server is failing
* and we should stop creating new sessions
*/
#define DNS_MAX_DSS_CONSECUTIVE_ERRORS 100
/* 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 */
} __attribute__ ((packed));
/* 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...)*/
} __attribute__ ((packed));
/* Structure describing a name server used during name resolution.
* A name server belongs to a resolvers section.
*/
struct dns_stream_server {
struct server *srv;
struct dns_ring *ring_req;
int consecutive_errors; /* number of errors since last successful query (atomically updated without lock) */
int maxconn;
int idle_conns;
int cur_conns;
int max_active_conns;
size_t ofs_req; // ring buffer reader offset
size_t ofs_rsp; // ring buffer reader offset
struct task *task_req; /* req conn management */
struct task *task_rsp; /* rsp management */
struct task *task_idle; /* handle idle sess */
struct list free_sess;
struct list idle_sess;
struct list wait_sess;
__decl_thread(HA_SPINLOCK_T lock); // lock to protect current struct
};
struct dns_dgram_server {
struct dgram_conn conn; /* transport layer */
struct dns_ring *ring_req;
size_t ofs_req; // ring buffer reader offset
};
struct dns_query {
struct eb32_node qid;
uint16_t original_qid;
int expire;
struct list list;
};
struct dns_session {
struct appctx *appctx; // appctx of current session
struct dns_stream_server *dss;
uint16_t tx_msg_offset;
int nb_queries;
int onfly_queries;
int query_counter;
struct list list;
struct list waiter;
struct list queries;
struct task *task_exp;
struct eb_root query_ids; /* tree to quickly lookup/retrieve query ids currently in use */
size_t ofs; // ring buffer reader offset
struct dns_ring ring;
struct {
uint16_t len;
uint16_t offset;
char *area;
} rx_msg;
unsigned char *tx_ring_area;
int shutdown;
};
/* Structure describing a name server
*/
struct dns_nameserver {
char *id; /* nameserver unique identifier */
void *parent;
unsigned int puid; /* parent-unique numeric id */
struct {
const char *file; /* file where the section appears */
int line; /* line where the section appears */
} conf; /* config information */
int (*process_responses)(struct dns_nameserver *ns); /* callback used to process responses */
struct dns_dgram_server *dgram; /* used for dgram dns */
struct dns_stream_server *stream; /* used for tcp dns */
EXTRA_COUNTERS(extra_counters);
struct dns_counters *counters;
struct list list; /* nameserver chained list */
};
/* mixed dns and resolver counters, we will have to split them */
struct dns_counters {
char *id; /* nameserver id */
char *pid; /* parent resolver id */
unsigned int ns_puid; /* nameserver numerical id (ns->puid) */
long long sent; /* - queries sent */
long long snd_error; /* - sending errors */
union {
struct {
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 */;
} resolver;
} app; /* application specific counteurs */
};
#endif /* _HAPROXY_DNS_T_H */
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