#ifndef DNSRESOLV_H
#define DNSRESOLV_H

/*
 *  Revision 20230613, Erwin Hoffmann
 *  - DNS_NXD (return code 0) for NXDOMAIN and NODATA added
 *  - DNS_SOFT as shortcut for DNS_ERR or DNS_COM
 *  - DNS_HARD indicates DNS loop problems
 *  Revision 20221101, Erwin Hoffmann
 *  - DNS_COM has now return code -3 (as documented; tx. Franz S.)
 *  Revision 20210922, Erwin Hoffmann
 *  - Added constants MAXMSGSIZE and MAXSEGMENT - not used yet
 *  Revision 20210401, Erwin Hoffmann
 *  - removed obsolete dns_sortip(); not going to work with GCC-10 anyway
 *  Revision 20200719, Erwin Hoffmann
 *  - added dns_qualify_localhost function including fqdn retrun
 *  Revision 20190730, Erwin Hoffmann
 *  - revised DNS_* return codes to make them compliant with ucspi-*
 *  Revision 20190430, Erwin Hoffmann
 *  - added DNS_SOFT/HARD/MEM complient to s/qmail
 *  - code changes in all decendent modules
 *  Revision 20180222, Erwin Hoffmann
 *  - we consider in total 32 NS IPs (IPv4 + IPv6)
 *  - added dns_transmit_start6
 *  - added uint32 scope_ids[32],
 *    the initial NS scopes read from /etc/resolv.conf et al.
 *  Revision 20180118, Erwin Hoffmann
 *  - included MSGSIZE for DNS messages (instead of MTUSIZE)
 *  Revision 20171231, Erwin Hoffmann
 *  - renamed to dnsresolv.h and removed *qmail declarations
 *  Revision 20170902, Erwin Hoffmann
 *  - added old definitions from *qmail for (temp) backwards compatibility
 *  - added more DNS RR definitions
 */

#include "iopause.h"
#include "stralloc.h"
#include "taia.h"

/* Note: The conventions are subject of change in forthcoming versions */

#define DNS_NXD  0  /* NXDOMAIN, NODATA */
#define DNS_MEM  -1 /* out of memory; fatal */
#define DNS_ERR  -2 /* parsing errors and others */
#define DNS_COM  -3 /* (socket) communication errors: SERVFAIL */
#define DNS_INT  -4 /* internal errors */
#define DNS_SOFT -5 /* DNS_ERR or DNS_COM */
#define DNS_HARD -6 /* DNS loop problem */

#define MSGSIZE MTUSIZE /* todays default */
// #define MSGSIZE 512              /* RFC 1035 */
#define MAXMSGSIZE 4096  /* 4069 seen with EDNS0 */
#define MAXSEGMENT 65535 /* Max TCP buffer size */

#define QUERY_MAXNS    32  /* 16 IPv4 + 16 IPv6 NS */
#define QUERY_MAXIPLEN 512 /* QUERY_MAXNS * 16 */

/* Note: These following definitions are subject of change */

#define DNS_C_IN  "\0\1"
#define DNS_C_ANY "\0\377"

#define DNS_T_A          "\0\1"
#define DNS_T_NS         "\0\2"
#define DNS_T_CNAME      "\0\5"
#define DNS_T_SOA        "\0\6"
#define DNS_T_PTR        "\0\14"
#define DNS_T_HINFO      "\0\15"
#define DNS_T_MX         "\0\17"
#define DNS_T_TXT        "\0\20"
#define DNS_T_RP         "\0\21"
#define DNS_T_SIG        "\0\30"
#define DNS_T_KEY        "\0\31"
#define DNS_T_AAAA       "\0\34"
#define DNS_T_SRV        "\0\41"
#define DNS_T_NAPTR      "\0\43"
#define DNS_T_CERT       "\0\45"
#define DNS_T_OPT        "\0\51"
#define DNS_T_DS         "\0\53"
#define DNS_T_SSHFP      "\0\54"
#define DNS_T_IPSECKEY   "\0\55"
#define DNS_T_RRSIG      "\0\56"
#define DNS_T_NSEC       "\0\57"
#define DNS_T_DNSKEY     "\0\60"
#define DNS_T_NSEC3      "\0\62"
#define DNS_T_NSEC3PARAM "\0\63"
#define DNS_T_TLSA       "\0\64"
#define DNS_T_HIP        "\0\67"
#define DNS_T_OPENPGPKEY "\0\75"
#define DNS_T_SPF        "\0\143"
#define DNS_T_AXFR       "\0\374"
#define DNS_T_ANY        "\0\377"
#define DNS_T_CAA        "\1\1"

#define LOCALHOST    "localhost" /* no clear distinction IPv4/IPv6 */
#define IP4_LOOPBACK "ip4-loopback"
#define IP6_LOOPBACK "ip6-loopback"

struct dns_transmit {
  char *query; /* 0, or dynamically allocated */
  unsigned int querylen;
  char *packet; /* 0, or dynamically allocated */
  unsigned int packetlen;
  int s1; /* 0, or 1 + an open file descriptor */
  int tcpstate;
  unsigned int udploop;
  unsigned int curserver;
  struct taia deadline;
  unsigned int pos;
  const char *servers;
  uint32 scope_id;
  char localip[16];
  char qtype[2];
};

/* General */

extern void dns_random_init(const char *);
extern unsigned int dns_random(unsigned int);

extern void dns_domain_free(char **);
extern int dns_domain_copy(char **, const char *);
extern unsigned int dns_domain_length(const char *);
extern int dns_domain_equal(const char *, const char *);
extern int dns_domain_suffix(const char *, const char *);
extern unsigned int dns_domain_suffixpos(const char *, const char *);
extern int dns_domain_fromdot(char **, const char *, unsigned int);
extern int dns_domain_todot_cat(stralloc *, const char *);
extern int dns_ip_qualify(stralloc *, stralloc *, const stralloc *);
extern int dns_ip_qualify_rules(stralloc *, stralloc *, const stralloc *, const stralloc *);
extern int dns_ip_qualify_localhost(stralloc *, stralloc *, const stralloc *);

extern unsigned int dns_packet_copy(const char *, unsigned int, unsigned int, char *, unsigned int);
extern unsigned int dns_packet_getname(const char *, unsigned int, unsigned int, char **);
extern unsigned int dns_packet_skipname(const char *, unsigned int, unsigned int);

extern struct dns_transmit dns_resolve_tx;
extern int dns_transmit_start(
    struct dns_transmit *, const char *, int, const char *, const char *, const char *);
extern void dns_transmit_free(struct dns_transmit *);
extern void dns_transmit_io(struct dns_transmit *, iopause_fd *, struct taia *);
extern int dns_transmit_get(struct dns_transmit *, const iopause_fd *, const struct taia *);

/* Common IPv4 + IPv6 */

extern int dns_resolvconfip(char *, uint32 *);
extern int dns_resolvconfrewrite(stralloc *);
extern int dns_resolve(const char *, const char *);

extern int dns_name(stralloc *, const char *);
extern int dns_name_packet(stralloc *, const char *, unsigned int);
extern int dns_txt_packet(stralloc *, const char *, unsigned int);
extern int dns_txt(stralloc *, const stralloc *);
extern int dns_mx_packet(stralloc *, const char *, unsigned int);
extern int dns_mx(stralloc *, const stralloc *);

/* IPv4 specific */

extern int dns_ip4_packet(stralloc *, const char *, unsigned int);
extern int dns_ip4(stralloc *, stralloc *);
extern void dns_sortip4(char *, unsigned int);

extern int dns_ip4_qualify_rules(stralloc *, stralloc *, const stralloc *, const stralloc *);
extern int dns_ip4_qualify(stralloc *, stralloc *, const stralloc *);

#define DNS_NAME4_DOMAIN 31
extern int dns_name4_domain(char *, const char *);
extern int dns_name4(stralloc *, const char *);
extern int randombind4(struct dns_transmit *);

/* IPv6 specific */

extern int dns_ip6_packet(stralloc *, const char *, unsigned int);
extern int dns_ip6(stralloc *, stralloc *);
extern void dns_sortip6(char *, unsigned int);

extern int dns_ip6_qualify_rules(stralloc *, stralloc *, const stralloc *, const stralloc *);
extern int dns_ip6_qualify(stralloc *, stralloc *, const stralloc *);

#define DNS_NAME6_DOMAIN (4 * 16 + 11)
extern int dns_name6_domain(char *, const char *);
extern int dns_name6(stralloc *, const char *);

extern int dns_cname_packet(stralloc *, const char *, unsigned int);
extern int dns_cname(stralloc *, stralloc *);

extern int dns_transmit_start6(
    struct dns_transmit *, const char *, int, const char *, const char *, const char *, const uint32 *);
extern int randombind6(struct dns_transmit *);

/* General */

extern void socketfree(struct dns_transmit *);
extern void queryfree(struct dns_transmit *);
extern void packetfree(struct dns_transmit *);
extern int serverwantstcp(const char *, unsigned int);
extern int serverfailed(const char *, unsigned int);
extern int getscopeid(const struct dns_transmit *, const char *);
extern int firstudp(struct dns_transmit *);
extern int nextudp(struct dns_transmit *);
extern int firsttcp(struct dns_transmit *);
extern int nexttcp(struct dns_transmit *);

#endif