FM / dns

/usr/include/bind9/dns

Name	Size	Mode	Actions
acache.h	14232	0644	edit dl rm
acl.h	7242	0644	edit dl rm
adb.h	22595	0644	edit dl rm
badcache.h	3369	0644	edit dl rm
bit.h	807	0644	edit dl rm
byaddr.h	4002	0644	edit dl rm
cache.h	8643	0644	edit dl rm
callbacks.h	2271	0644	edit dl rm
catz.h	11833	0644	edit dl rm
cert.h	1466	0644	edit dl rm
client.h	22042	0644	edit dl rm
clientinfo.h	2006	0644	edit dl rm
compress.h	6646	0644	edit dl rm
db.h	47061	0644	edit dl rm
dbiterator.h	7422	0644	edit dl rm
dbtable.h	3165	0644	edit dl rm
diff.h	6980	0644	edit dl rm
dispatch.h	16427	0644	edit dl rm
dlz.h	10618	0644	edit dl rm
dlz_dlopen.h	4677	0644	edit dl rm
dns64.h	5635	0644	edit dl rm
dnssec.h	12371	0644	edit dl rm
dnstap.h	9364	0644	edit dl rm
ds.h	1225	0644	edit dl rm
dsdigest.h	1722	0644	edit dl rm
dyndb.h	4835	0644	edit dl rm
ecdb.h	809	0644	edit dl rm
edns.h	722	0644	edit dl rm
enumclass.h	1220	0644	edit dl rm
enumtype.h	8300	0644	edit dl rm
events.h	4059	0644	edit dl rm
fixedname.h	1663	0644	edit dl rm
forward.h	3452	0644	edit dl rm
geoip.h	2792	0644	edit dl rm
ipkeylist.h	2186	0644	edit dl rm
iptable.h	1621	0644	edit dl rm
journal.h	8227	0644	edit dl rm
keydata.h	1059	0644	edit dl rm
keyflags.h	1278	0644	edit dl rm
keytable.h	9462	0644	edit dl rm
keyvalues.h	4159	0644	edit dl rm
lib.h	1192	0644	edit dl rm
log.h	3964	0644	edit dl rm
lookup.h	2924	0644	edit dl rm
master.h	11289	0644	edit dl rm
masterdump.h	12647	0644	edit dl rm
message.h	39023	0644	edit dl rm
name.h	37115	0644	edit dl rm
ncache.h	4929	0644	edit dl rm
nsec.h	3397	0644	edit dl rm
nsec3.h	8032	0644	edit dl rm
nta.h	4548	0644	edit dl rm
opcode.h	1007	0644	edit dl rm
order.h	1999	0644	edit dl rm
peer.h	5966	0644	edit dl rm
portlist.h	2101	0644	edit dl rm
private.h	1935	0644	edit dl rm
rbt.h	40618	0644	edit dl rm
rcode.h	2481	0644	edit dl rm
rdata.h	21613	0644	edit dl rm
rdataclass.h	2257	0644	edit dl rm
rdatalist.h	2569	0644	edit dl rm
rdataset.h	21536	0644	edit dl rm
rdatasetiter.h	3926	0644	edit dl rm
rdataslab.h	4528	0644	edit dl rm
rdatastruct.h	61584	0644	edit dl rm
rdatatype.h	2298	0644	edit dl rm
request.h	11156	0644	edit dl rm
resolver.h	20227	0644	edit dl rm
result.h	9284	0644	edit dl rm
rootns.h	892	0644	edit dl rm
rpz.h	10335	0644	edit dl rm
rriterator.h	4230	0644	edit dl rm
rrl.h	6640	0644	edit dl rm
sdb.h	7224	0644	edit dl rm
sdlz.h	14214	0644	edit dl rm
secalg.h	1706	0644	edit dl rm
secproto.h	1557	0644	edit dl rm
soa.h	2186	0644	edit dl rm
ssu.h	8308	0644	edit dl rm
stats.h	13451	0644	edit dl rm
tcpmsg.h	3145	0644	edit dl rm
time.h	1695	0644	edit dl rm
timer.h	1051	0644	edit dl rm
tkey.h	7631	0644	edit dl rm
tsec.h	2949	0644	edit dl rm
tsig.h	8384	0644	edit dl rm
ttl.h	1945	0644	edit dl rm
types.h	14212	0644	edit dl rm
update.h	1653	0644	edit dl rm
validator.h	7161	0644	edit dl rm
version.h	868	0644	edit dl rm
view.h	35274	0644	edit dl rm
xfrin.h	2924	0644	edit dl rm
zone.h	60864	0644	edit dl rm
zonekey.h	777	0644	edit dl rm
zt.h	5562	0644	edit dl rm

Edit: /usr/include/bind9/dns/rrl.h (6640B)

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#ifndef DNS_RRL_H
#define DNS_RRL_H 1

/*
 * Rate limit DNS responses.
 */

#include <inttypes.h>
#include <stdbool.h>

#include <isc/lang.h>

#include <dns/fixedname.h>
#include <dns/rdata.h>
#include <dns/types.h>

ISC_LANG_BEGINDECLS

/*
 * Memory allocation or other failures.
 */
#define DNS_RRL_LOG_FAIL	ISC_LOG_WARNING
/*
 * dropped or slipped responses.
 */
#define DNS_RRL_LOG_DROP	ISC_LOG_INFO
/*
 * Major events in dropping or slipping.
 */
#define DNS_RRL_LOG_DEBUG1	ISC_LOG_DEBUG(3)
/*
 * Limit computations.
 */
#define DNS_RRL_LOG_DEBUG2	ISC_LOG_DEBUG(4)
/*
 * Even less interesting.
 */
#define DNS_RRL_LOG_DEBUG3	ISC_LOG_DEBUG(9)

#define DNS_RRL_LOG_ERR_LEN	64
#define DNS_RRL_LOG_BUF_LEN	(sizeof("would continue limiting") +	\
				 DNS_RRL_LOG_ERR_LEN +			\
				 sizeof(" responses to ") +		\
				 ISC_NETADDR_FORMATSIZE +		\
				 sizeof("/128 for IN ") +		\
				 DNS_RDATATYPE_FORMATSIZE +		\
				 DNS_NAME_FORMATSIZE)

typedef struct dns_rrl_hash dns_rrl_hash_t;

/*
 * Response types.
 */
typedef enum {
	DNS_RRL_RTYPE_FREE = 0,
	DNS_RRL_RTYPE_QUERY,
	DNS_RRL_RTYPE_REFERRAL,
	DNS_RRL_RTYPE_NODATA,
	DNS_RRL_RTYPE_NXDOMAIN,
	DNS_RRL_RTYPE_ERROR,
	DNS_RRL_RTYPE_ALL,
	DNS_RRL_RTYPE_TCP,
} dns_rrl_rtype_t;

/*
 * A rate limit bucket key.
 * This should be small to limit the total size of the database.
 * The hash of the qname should be wide enough to make the probability
 * of collisions among requests from a single IP address block less than 50%.
 * We need a 32-bit hash value for 10000 qps (e.g. random qnames forged
 * by attacker) to collide with legitimate qnames from the target with
 * probability at most 1%.
 */
#define DNS_RRL_MAX_PREFIX  64
typedef union dns_rrl_key dns_rrl_key_t;
struct dns__rrl_key {
	uint32_t	    ip[DNS_RRL_MAX_PREFIX/32];
	uint32_t	    qname_hash;
	dns_rdatatype_t	    qtype;
	uint8_t         qclass;
	unsigned int	    rtype   :4; /* dns_rrl_rtype_t */
	unsigned int	    ipv6    :1;
};
union dns_rrl_key {
	struct dns__rrl_key s;
	uint16_t	w[sizeof(struct dns__rrl_key)/sizeof(uint16_t)];
};

/*
 * A rate-limit entry.
 * This should be small to limit the total size of the table of entries.
 */
typedef struct dns_rrl_entry dns_rrl_entry_t;
typedef ISC_LIST(dns_rrl_entry_t) dns_rrl_bin_t;
struct dns_rrl_entry {
	ISC_LINK(dns_rrl_entry_t) lru;
	ISC_LINK(dns_rrl_entry_t) hlink;
	dns_rrl_key_t	key;
# define DNS_RRL_RESPONSE_BITS	24
	signed int	responses   :DNS_RRL_RESPONSE_BITS;
# define DNS_RRL_QNAMES_BITS	8
	unsigned int	log_qname   :DNS_RRL_QNAMES_BITS;

# define DNS_RRL_TS_GEN_BITS	2
	unsigned int	ts_gen	    :DNS_RRL_TS_GEN_BITS;
	unsigned int	ts_valid    :1;
# define DNS_RRL_HASH_GEN_BITS	1
	unsigned int	hash_gen    :DNS_RRL_HASH_GEN_BITS;
	unsigned int	logged	    :1;
# define DNS_RRL_LOG_BITS	11
	unsigned int	log_secs    :DNS_RRL_LOG_BITS;

# define DNS_RRL_TS_BITS	12
	unsigned int	ts	    :DNS_RRL_TS_BITS;

# define DNS_RRL_MAX_SLIP	10
	unsigned int	slip_cnt    :4;
};

#define DNS_RRL_MAX_TIME_TRAVEL	5
#define DNS_RRL_FOREVER		(1<<DNS_RRL_TS_BITS)
#define DNS_RRL_MAX_TS		(DNS_RRL_FOREVER - 1)

#define DNS_RRL_MAX_RESPONSES	((1<<(DNS_RRL_RESPONSE_BITS-1))-1)
#define DNS_RRL_MAX_WINDOW	3600
#if DNS_RRL_MAX_WINDOW >= DNS_RRL_MAX_TS
#error "DNS_RRL_MAX_WINDOW is too large"
#endif
#define DNS_RRL_MAX_RATE	1000
#if DNS_RRL_MAX_RATE >= (DNS_RRL_MAX_RESPONSES / DNS_RRL_MAX_WINDOW)
#error "DNS_RRL_MAX_rate is too large"
#endif

#if (1<<DNS_RRL_LOG_BITS) >= DNS_RRL_FOREVER
#error DNS_RRL_LOG_BITS is too big
#endif
#define DNS_RRL_MAX_LOG_SECS	1800
#if DNS_RRL_MAX_LOG_SECS >= (1<<DNS_RRL_LOG_BITS)
#error "DNS_RRL_MAX_LOG_SECS is too large"
#endif
#define DNS_RRL_STOP_LOG_SECS	60
#if DNS_RRL_STOP_LOG_SECS >= (1<<DNS_RRL_LOG_BITS)
#error "DNS_RRL_STOP_LOG_SECS is too large"
#endif

/*
 * A hash table of rate-limit entries.
 */
struct dns_rrl_hash {
	isc_stdtime_t	check_time;
	unsigned int	gen	    :DNS_RRL_HASH_GEN_BITS;
	int		length;
	dns_rrl_bin_t	bins[1];
};

/*
 * A block of rate-limit entries.
 */
typedef struct dns_rrl_block dns_rrl_block_t;
struct dns_rrl_block {
	ISC_LINK(dns_rrl_block_t) link;
	int		size;
	dns_rrl_entry_t	entries[1];
};

/*
 * A rate limited qname buffer.
 */
typedef struct dns_rrl_qname_buf dns_rrl_qname_buf_t;
struct dns_rrl_qname_buf {
	ISC_LINK(dns_rrl_qname_buf_t) link;
	const dns_rrl_entry_t *e;
	unsigned int	    index;
	dns_fixedname_t	    qname;
};

typedef struct dns_rrl_rate dns_rrl_rate_t;
struct dns_rrl_rate {
	int	    r;
	int	    scaled;
	const char  *str;
};

/*
 * Per-view query rate limit parameters and a pointer to database.
 */
typedef struct dns_rrl dns_rrl_t;
struct dns_rrl {
	isc_mutex_t	lock;
	isc_mem_t	*mctx;

bool	log_only;
	dns_rrl_rate_t	responses_per_second;
	dns_rrl_rate_t	referrals_per_second;
	dns_rrl_rate_t	nodata_per_second;
	dns_rrl_rate_t	nxdomains_per_second;
	dns_rrl_rate_t	errors_per_second;
	dns_rrl_rate_t	all_per_second;
	dns_rrl_rate_t	slip;
	int		window;
	double		qps_scale;
	int		max_entries;

dns_acl_t	*exempt;

int		num_entries;

int		qps_responses;
	isc_stdtime_t	qps_time;
	double		qps;

unsigned int	probes;
	unsigned int	searches;

ISC_LIST(dns_rrl_block_t) blocks;
	ISC_LIST(dns_rrl_entry_t) lru;

dns_rrl_hash_t	*hash;
	dns_rrl_hash_t	*old_hash;
	unsigned int	hash_gen;

unsigned int	ts_gen;
# define DNS_RRL_TS_BASES   (1<<DNS_RRL_TS_GEN_BITS)
	isc_stdtime_t	ts_bases[DNS_RRL_TS_BASES];

int		ipv4_prefixlen;
	uint32_t	ipv4_mask;
	int		ipv6_prefixlen;
	uint32_t	ipv6_mask[4];

isc_stdtime_t	log_stops_time;
	dns_rrl_entry_t	*last_logged;
	int		num_logged;
	int		num_qnames;
	ISC_LIST(dns_rrl_qname_buf_t) qname_free;
# define DNS_RRL_QNAMES	    (1<<DNS_RRL_QNAMES_BITS)
	dns_rrl_qname_buf_t *qnames[DNS_RRL_QNAMES];
};

typedef enum {
	DNS_RRL_RESULT_OK,
	DNS_RRL_RESULT_DROP,
	DNS_RRL_RESULT_SLIP,
} dns_rrl_result_t;

dns_rrl_result_t
dns_rrl(dns_view_t *view,
	const isc_sockaddr_t *client_addr, bool is_tcp,
	dns_rdataclass_t rdclass, dns_rdatatype_t qtype,
	dns_name_t *qname, isc_result_t resp_result, isc_stdtime_t now,
	bool wouldlog, char *log_buf, unsigned int log_buf_len);

void
dns_rrl_view_destroy(dns_view_t *view);

isc_result_t
dns_rrl_init(dns_rrl_t **rrlp, dns_view_t *view, int min_entries);

ISC_LANG_ENDDECLS

#endif /* DNS_RRL_H */

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