FM / dns

/usr/include/bind9/dns

Name	Size	Mode	Actions
acl.h	6477	0644	edit dl rm
adb.h	22267	0644	edit dl rm
badcache.h	3387	0644	edit dl rm
bit.h	798	0644	edit dl rm
byaddr.h	3598	0644	edit dl rm
cache.h	8730	0644	edit dl rm
callbacks.h	2280	0644	edit dl rm
catz.h	11881	0644	edit dl rm
cert.h	1465	0644	edit dl rm
client.h	14527	0644	edit dl rm
clientinfo.h	2015	0644	edit dl rm
compress.h	7047	0644	edit dl rm
db.h	50446	0644	edit dl rm
dbiterator.h	7385	0644	edit dl rm
dbtable.h	3167	0644	edit dl rm
diff.h	7039	0644	edit dl rm
dispatch.h	15538	0644	edit dl rm
dlz.h	10876	0644	edit dl rm
dlz_dlopen.h	4394	0644	edit dl rm
dns64.h	5720	0644	edit dl rm
dnsrps.h	2572	0644	edit dl rm
dnssec.h	12841	0644	edit dl rm
dnstap.h	10193	0644	edit dl rm
ds.h	1665	0644	edit dl rm
dsdigest.h	1713	0644	edit dl rm
dyndb.h	4869	0644	edit dl rm
ecdb.h	806	0644	edit dl rm
ecs.h	1250	0644	edit dl rm
edns.h	783	0644	edit dl rm
enumclass.h	1220	0644	edit dl rm
enumtype.h	8485	0644	edit dl rm
events.h	4451	0644	edit dl rm
fixedname.h	1652	0644	edit dl rm
forward.h	3060	0644	edit dl rm
geoip.h	2340	0644	edit dl rm
ipkeylist.h	2219	0644	edit dl rm
iptable.h	1521	0644	edit dl rm
journal.h	9712	0644	edit dl rm
kasp.h	12124	0644	edit dl rm
keydata.h	1047	0644	edit dl rm
keyflags.h	1277	0644	edit dl rm
keymgr.h	4107	0644	edit dl rm
keytable.h	7871	0644	edit dl rm
keyvalues.h	4083	0644	edit dl rm
lib.h	993	0644	edit dl rm
librpz.h	31401	0644	edit dl rm
lmdb.h	779	0644	edit dl rm
log.h	4029	0644	edit dl rm
lookup.h	2921	0644	edit dl rm
master.h	8786	0644	edit dl rm
masterdump.h	10133	0644	edit dl rm
message.h	39567	0644	edit dl rm
name.h	37781	0644	edit dl rm
ncache.h	4960	0644	edit dl rm
nsec.h	3065	0644	edit dl rm
nsec3.h	8258	0644	edit dl rm
nta.h	4846	0644	edit dl rm
opcode.h	1006	0644	edit dl rm
order.h	2010	0644	edit dl rm
peer.h	6475	0644	edit dl rm
portlist.h	2101	0644	edit dl rm
private.h	1962	0644	edit dl rm
rbt.h	37484	0644	edit dl rm
rcode.h	2472	0644	edit dl rm
rdata.h	22564	0644	edit dl rm
rdataclass.h	2248	0644	edit dl rm
rdatalist.h	2557	0644	edit dl rm
rdataset.h	18714	0644	edit dl rm
rdatasetiter.h	3912	0644	edit dl rm
rdataslab.h	4267	0644	edit dl rm
rdatastruct.h	62703	0644	edit dl rm
rdatatype.h	2290	0644	edit dl rm
request.h	9187	0644	edit dl rm
resolver.h	20152	0644	edit dl rm
result.h	9196	0644	edit dl rm
rootns.h	891	0644	edit dl rm
rpz.h	12156	0644	edit dl rm
rriterator.h	4214	0644	edit dl rm
rrl.h	6959	0644	edit dl rm
sdb.h	7350	0644	edit dl rm
sdlz.h	14090	0644	edit dl rm
secalg.h	1705	0644	edit dl rm
secproto.h	1556	0644	edit dl rm
soa.h	2179	0644	edit dl rm
ssu.h	7182	0644	edit dl rm
stats.h	24689	0644	edit dl rm
tcpmsg.h	3128	0644	edit dl rm
time.h	1693	0644	edit dl rm
timer.h	1050	0644	edit dl rm
tkey.h	7655	0644	edit dl rm
tsec.h	2946	0644	edit dl rm
tsig.h	8497	0644	edit dl rm
ttl.h	1876	0644	edit dl rm
types.h	14584	0644	edit dl rm
update.h	2004	0644	edit dl rm
validator.h	6679	0644	edit dl rm
version.h	679	0644	edit dl rm
view.h	35341	0644	edit dl rm
xfrin.h	2314	0644	edit dl rm
zone.h	65543	0644	edit dl rm
zonekey.h	776	0644	edit dl rm
zoneverify.h	1393	0644	edit dl rm
zt.h	5241	0644	edit dl rm

Edit: /usr/include/bind9/dns/rrl.h (6959B)

/*
 * 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 /* if DNS_RRL_MAX_WINDOW >= DNS_RRL_MAX_TS */
#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 DNS_RRL_MAX_RATE >= (DNS_RRL_MAX_RESPONSES / DNS_RRL_MAX_WINDOW) \
	*/

#if (1 << DNS_RRL_LOG_BITS) >= DNS_RRL_FOREVER
#error DNS_RRL_LOG_BITS is too big
#endif /* if (1 << DNS_RRL_LOG_BITS) >= DNS_RRL_FOREVER */
#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 /* if DNS_RRL_MAX_LOG_SECS >= (1 << DNS_RRL_LOG_BITS) */
#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 /* if DNS_RRL_STOP_LOG_SECS >= (1 << DNS_RRL_LOG_BITS) */

/*
 * 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,
	const 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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