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      1 /* rrl.h - Response Rate Limiting for NSD.
      2  * By W.C.A. Wijngaards
      3  * Copyright 2012, NLnet Labs.
      4  * BSD, see LICENSE.
      5  */
      6 #ifndef RRL_H
      7 #define RRL_H
      8 #include "query.h"
      9 
     10 /** the classification types for the rrl */
     11 enum rrl_type {
     12 	/* classification types */
     13 	rrl_type_nxdomain	= 0x01,
     14 	rrl_type_error		= 0x02,
     15 	rrl_type_referral	= 0x04,
     16 	rrl_type_any		= 0x08,
     17 	rrl_type_wildcard	= 0x10,
     18 	rrl_type_nodata		= 0x20,
     19 	rrl_type_dnskey		= 0x40,
     20 	rrl_type_positive	= 0x80,
     21 	rrl_type_rrsig		= 0x100,
     22 
     23 	/* all classification types */
     24 	rrl_type_all		= 0x1ff,
     25 	/* to distinguish between ip4 and ip6 netblocks, used in code */
     26 	rrl_ip6			= 0x8000
     27 };
     28 
     29 /** Number of buckets */
     30 #define RRL_BUCKETS 1000000
     31 /** default rrl limit, in 2x qps , the default is 200 qps */
     32 #define RRL_LIMIT 400
     33 /** default slip */
     34 #define RRL_SLIP 2
     35 /** default prefix lengths */
     36 #define RRL_IPV4_PREFIX_LENGTH 24
     37 #define RRL_IPV6_PREFIX_LENGTH 64
     38 /** default whitelist rrl limit, in 2x qps, default is thus 2000 qps */
     39 #define RRL_WLIST_LIMIT 4000
     40 
     41 /**
     42  * Initialize for n children (optional, otherwise no mmaps used)
     43  * ratelimits lm and wlm are in qps (this routines x2s them for internal use).
     44  * plf and pls are in prefix lengths.
     45  */
     46 void rrl_mmap_init(int numch, size_t numbuck, size_t lm, size_t wlm, size_t sm,
     47 	size_t plf, size_t pls);
     48 
     49 /**
     50  * Initialize rate limiting (for this child server process)
     51  */
     52 void rrl_init(size_t ch);
     53 
     54 /** deinit (for this child server process) */
     55 void rrl_deinit(size_t ch);
     56 
     57 /** deinit mmaps for n children */
     58 void rrl_mmap_deinit(void);
     59 /** frees memory but keeps mmap in place (for other processes) */
     60 void rrl_mmap_deinit_keep_mmap(void);
     61 
     62 /**
     63  * Process query that happens, the query structure contains the
     64  * information about the query and the answer.
     65  * returns true if the query is ratelimited.
     66  */
     67 int rrl_process_query(query_type* query);
     68 
     69 /**
     70  * Deny the query, with slip.
     71  * Returns DISCARD or PROCESSED(with TC flag).
     72  */
     73 query_state_type rrl_slip(query_type* query);
     74 
     75 /** convert classification type to string */
     76 const char* rrltype2str(enum rrl_type c);
     77 /** convert string to classification type */
     78 enum rrl_type rrlstr2type(const char* s);
     79 
     80 /** for unit test, update rrl bucket; return rate */
     81 uint32_t rrl_update(query_type* query, uint32_t hash, uint64_t source,
     82 	uint16_t flags, int32_t now, uint32_t lm);
     83 /** set the rate limit counters, pass variables in qps */
     84 void rrl_set_limit(size_t lm, size_t wlm, size_t sm);
     85 
     86 #endif /* RRL_H */
     87