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      1 /*
      2  * edns.h -- EDNS definitions (RFC 2671).
      3  *
      4  * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
      5  *
      6  * See LICENSE for the license.
      7  *
      8  */
      9 
     10 #ifndef EDNS_H
     11 #define EDNS_H
     12 
     13 #include "buffer.h"
     14 struct nsd;
     15 struct query;
     16 
     17 #define OPT_LEN 9U                      /* Length of the NSD EDNS response record minus 2 */
     18 #define OPT_RDATA 2                     /* holds the rdata length comes after OPT_LEN */
     19 #define OPT_HDR 4U                      /* NSID opt header length */
     20 #define NSID_CODE       3               /* nsid option code */
     21 #define COOKIE_CODE    10               /* COOKIE option code */
     22 #define EDE_CODE       15               /* Extended DNS Errors option code */
     23 #define ZONEVERSION_CODE 19             /* ZONEVERSION option code */
     24 #define DNSSEC_OK_MASK  0x8000U         /* do bit mask */
     25 
     26 /* https://iana.org/assignments/dns-parameters/#zoneversion-type-values */
     27 #define ZONEVERSION_SOA_SERIAL 0
     28 
     29 struct edns_data
     30 {
     31 	unsigned char ok[OPT_LEN];
     32 	unsigned char error[OPT_LEN];
     33 	unsigned char rdata_none[OPT_RDATA];
     34 	unsigned char nsid[OPT_HDR];
     35 	unsigned char cookie[OPT_HDR];
     36 };
     37 typedef struct edns_data edns_data_type;
     38 
     39 enum edns_status
     40 {
     41 	EDNS_NOT_PRESENT,
     42 	EDNS_OK,
     43 	/* EDNS states may be extended in the future */
     44 	EDNS_ERROR
     45 };
     46 typedef enum edns_status edns_status_type;
     47 
     48 enum cookie_status
     49 {
     50 	COOKIE_NOT_PRESENT,
     51 	COOKIE_UNVERIFIED,
     52 	COOKIE_VALID,
     53 	COOKIE_VALID_REUSE,
     54 	COOKIE_INVALID
     55 };
     56 typedef enum cookie_status cookie_status_type;
     57 
     58 struct edns_record
     59 {
     60 	edns_status_type   status;
     61 	size_t             position;
     62 	size_t             maxlen;
     63 	size_t		   opt_reserved_space;
     64 	int                dnssec_ok;
     65 	int                nsid;
     66 	int                zoneversion;
     67 	cookie_status_type cookie_status;
     68 	size_t             cookie_len;
     69 	uint8_t            cookie[40];
     70 	int                ede; /* RFC 8914 - Extended DNS Errors */
     71 	char*              ede_text; /* RFC 8914 - Extended DNS Errors text*/
     72 	uint16_t           ede_text_len;
     73 };
     74 typedef struct edns_record edns_record_type;
     75 
     76 /* The Extended DNS Error codes (RFC8914) we use */
     77 #define EDE_OTHER              0
     78 #define EDE_NOT_READY         14
     79 #define EDE_PROHIBITED        18
     80 #define EDE_NOT_AUTHORITATIVE 20
     81 #define EDE_NOT_SUPPORTED     21
     82 #define EDE_INVALID_DATA      24
     83 
     84 /* ASSIGN_EDE_CODE_AND_STRING_LITERAL may only be used with string literals.
     85  * This is guaranteed by concatenating and empty string to LITERAL, which
     86  * will make compilation fail if this macro is used with variables.
     87  */
     88 #define ASSIGN_EDE_CODE_AND_STRING_LITERAL(EDE, CODE, LITERAL)	\
     89 	do {							\
     90 		EDE = (CODE);					\
     91 		EDE ## _text = (LITERAL "");			\
     92 		EDE ## _text_len = sizeof(LITERAL) - 1;		\
     93 	} while (0)
     94 
     95 void edns_init_data(edns_data_type *data, uint16_t max_length);
     96 void edns_init_record(edns_record_type *data);
     97 int edns_parse_record(edns_record_type *data, buffer_type *packet,
     98 	struct query* q, struct nsd* nsd);
     99 
    100 /*
    101  * The amount of space to reserve in the response for the EDNS data
    102  * (if required).
    103  */
    104 size_t edns_reserved_space(edns_record_type *data);
    105 
    106 void edns_init_nsid(edns_data_type *data, uint16_t nsid_len);
    107 
    108 void cookie_verify(struct query *q, struct nsd* nsd, uint32_t *now_p);
    109 void cookie_create(struct query *q, struct nsd* nsd, uint32_t *now_p);
    110 
    111 #endif /* EDNS_H */
    112