/*
* edns.h -- EDNS definitions (RFC 2671).
*
* Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
*
* See LICENSE for the license.
*
*/

#ifndef EDNS_H
#define EDNS_H

#include "buffer.h"
struct nsd;
struct query;

#define OPT_LEN 9U                      /* Length of the NSD EDNS response record minus 2 */
#define OPT_RDATA 2                     /* holds the rdata length comes after OPT_LEN */
#define OPT_HDR 4U                      /* NSID opt header length */
#define NSID_CODE       3               /* nsid option code */
#define COOKIE_CODE    10               /* COOKIE option code */
#define EDE_CODE       15               /* Extended DNS Errors option code */
#define DNSSEC_OK_MASK  0x8000U         /* do bit mask */

struct edns_data
{
       char ok[OPT_LEN];
       char error[OPT_LEN];
       char rdata_none[OPT_RDATA];
       char nsid[OPT_HDR];
       char cookie[OPT_HDR];
};
typedef struct edns_data edns_data_type;

enum edns_status
{
       EDNS_NOT_PRESENT,
       EDNS_OK,
       /* EDNS states may be extended in the future */
       EDNS_ERROR
};
typedef enum edns_status edns_status_type;

enum cookie_status
{
       COOKIE_NOT_PRESENT,
       COOKIE_UNVERIFIED,
       COOKIE_VALID,
       COOKIE_VALID_REUSE,
       COOKIE_INVALID
};
typedef enum cookie_status cookie_status_type;

struct edns_record
{
       edns_status_type   status;
       size_t             position;
       size_t             maxlen;
       size_t             opt_reserved_space;
       int                dnssec_ok;
       int                nsid;
       cookie_status_type cookie_status;
       size_t             cookie_len;
       uint8_t            cookie[40];
       int                ede; /* RFC 8914 - Extended DNS Errors */
       char*              ede_text; /* RFC 8914 - Extended DNS Errors text*/
       uint16_t           ede_text_len;
};
typedef struct edns_record edns_record_type;

/* The Extended DNS Error codes (RFC8914) we use */
#define EDE_OTHER              0
#define EDE_NOT_READY         14
#define EDE_PROHIBITED        18
#define EDE_NOT_AUTHORITATIVE 20
#define EDE_NOT_SUPPORTED     21
#define EDE_INVALID_DATA      24

/* ASSIGN_EDE_CODE_AND_STRING_LITERAL may only be used with string literals.
* This is guaranteed by concatenating and empty string to LITERAL, which
* will make compilation fail if this macro is used with variables.
*/
#define ASSIGN_EDE_CODE_AND_STRING_LITERAL(EDE, CODE, LITERAL)  \
       do {                                                    \
               EDE = (CODE);                                   \
               EDE ## _text = (LITERAL "");                    \
               EDE ## _text_len = sizeof(LITERAL) - 1;         \
       } while (0)

void edns_init_data(edns_data_type *data, uint16_t max_length);
void edns_init_record(edns_record_type *data);
int edns_parse_record(edns_record_type *data, buffer_type *packet,
       struct query* q, struct nsd* nsd);

/*
* The amount of space to reserve in the response for the EDNS data
* (if required).
*/
size_t edns_reserved_space(edns_record_type *data);

void edns_init_nsid(edns_data_type *data, uint16_t nsid_len);

void cookie_verify(struct query *q, struct nsd* nsd, uint32_t *now_p);
void cookie_create(struct query *q, struct nsd* nsd, uint32_t *now_p);

#endif /* EDNS_H */