#pragma once

#include <netinet/ip.h>

#include <netinet/udp.h>

#include "hashmap.h"

#include "in-addr-util.h"

#include "macro.h"

#include "sparse-endian.h"

typedef struct DnsPacketHeader DnsPacketHeader;

typedef struct DnsPacket DnsPacket;

#include "resolved-def.h"

#include "resolved-dns-answer.h"

#include "resolved-dns-question.h"

#include "resolved-dns-rr.h"

typedef enum DnsProtocol {

DNS_PROTOCOL_DNS,

DNS_PROTOCOL_MDNS,

DNS_PROTOCOL_LLMNR,

_DNS_PROTOCOL_MAX,

_DNS_PROTOCOL_INVALID = -1

} DnsProtocol;

struct DnsPacketHeader {

uint16_t id;

be16_t flags;

be16_t qdcount;

be16_t ancount;

be16_t nscount;

be16_t arcount;

};

#define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)

#define UDP_PACKET_HEADER_SIZE (sizeof(struct iphdr) + sizeof(struct udphdr))

#define DNS_PACKET_SIZE_MAX 0xFFFF

#define DNS_PACKET_UNICAST_SIZE_MAX 512

#define DNS_PACKET_UNICAST_SIZE_LARGE_MAX 4096

#define DNS_PACKET_SIZE_START 512

struct DnsPacket {

int n_ref;

DnsProtocol protocol;

size_t size, allocated, rindex;

void *_data; /* don't access directly, use DNS_PACKET_DATA()! */

Hashmap *names; /* For name compression */

size_t opt_start, opt_size;

/* Parsed data */

DnsQuestion *question;

DnsAnswer *answer;

DnsResourceRecord *opt;

/* Packet reception metadata */

int ifindex;

int family, ipproto;

union in_addr_union sender, destination;

uint16_t sender_port, destination_port;

uint32_t ttl;

/* For support of truncated packets */

DnsPacket *more;

bool on_stack:1;

bool extracted:1;

bool refuse_compression:1;

bool canonical_form:1;

};

static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {

if (_unlikely_(!p))

return NULL;

if (p->_data)

return p->_data;

return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket));

}

#define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))

#define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id

#define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)

#define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)

#define DNS_PACKET_AA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 10) & 1)

#define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)

#define DNS_PACKET_RD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 8) & 1)

#define DNS_PACKET_RA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 7) & 1)

#define DNS_PACKET_AD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 5) & 1)

#define DNS_PACKET_CD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 4) & 1)

static inline uint16_t DNS_PACKET_RCODE(DnsPacket *p) {

uint16_t rcode;

if (p->opt)

rcode = (uint16_t) (p->opt->ttl >> 24);

else

rcode = 0;

return rcode | (be16toh(DNS_PACKET_HEADER(p)->flags) & 15);

}

#define DNS_PACKET_LLMNR_C(p) DNS_PACKET_AA(p)

#define DNS_PACKET_LLMNR_T(p) DNS_PACKET_RD(p)

#define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)

#define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)

#define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)

#define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)

#define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \

(((uint16_t) !!(qr) << 15) | \

((uint16_t) ((opcode) & 15) << 11) | \

((uint16_t) !!(aa) << 10) | /* on LLMNR: c */ \

((uint16_t) !!(tc) << 9) | \

((uint16_t) !!(rd) << 8) | /* on LLMNR: t */ \

((uint16_t) !!(ra) << 7) | \

((uint16_t) !!(ad) << 5) | \

((uint16_t) !!(cd) << 4) | \

((uint16_t) ((rcode) & 15)))

static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket *p) {

return

(unsigned) DNS_PACKET_ANCOUNT(p) +

(unsigned) DNS_PACKET_NSCOUNT(p) +

(unsigned) DNS_PACKET_ARCOUNT(p);

}

int dns_packet_new(DnsPacket **p, DnsProtocol protocol, size_t mtu);

int dns_packet_new_query(DnsPacket **p, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled);

void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated);

DnsPacket *dns_packet_ref(DnsPacket *p);

DnsPacket *dns_packet_unref(DnsPacket *p);

DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref);

int dns_packet_validate(DnsPacket *p);

int dns_packet_validate_reply(DnsPacket *p);

int dns_packet_validate_query(DnsPacket *p);

int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key);

int dns_packet_append_blob(DnsPacket *p, const void *d, size_t sz, size_t *start);

int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start);

int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start);

int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start);

int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start);

int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start);

int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, bool canonical_candidate, size_t *start);

int dns_packet_append_name(DnsPacket *p, const char *name, bool allow_compression, bool canonical_candidate, size_t *start);

int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, size_t *start);

int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start);

int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start);

void dns_packet_truncate(DnsPacket *p, size_t sz);

int dns_packet_truncate_opt(DnsPacket *p);

int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);

int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start);

int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start);

int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start);

int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start);

int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start);

int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start);

int dns_packet_read_name(DnsPacket *p, char **ret, bool allow_compression, size_t *start);

int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start);

int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start);

void dns_packet_rewind(DnsPacket *p, size_t idx);

int dns_packet_skip_question(DnsPacket *p);

int dns_packet_extract(DnsPacket *p);

static inline bool DNS_PACKET_SHALL_CACHE(DnsPacket *p) {

/* Never cache data originating from localhost, under the

return in_addr_is_localhost(p->family, &p->sender) == 0;

}

enum {

DNS_RCODE_SUCCESS = 0,

DNS_RCODE_FORMERR = 1,

DNS_RCODE_SERVFAIL = 2,

DNS_RCODE_NXDOMAIN = 3,

DNS_RCODE_NOTIMP = 4,

DNS_RCODE_REFUSED = 5,

DNS_RCODE_YXDOMAIN = 6,

DNS_RCODE_YXRRSET = 7,

DNS_RCODE_NXRRSET = 8,

DNS_RCODE_NOTAUTH = 9,

DNS_RCODE_NOTZONE = 10,

DNS_RCODE_BADVERS = 16,

DNS_RCODE_BADSIG = 16, /* duplicate value! */

DNS_RCODE_BADKEY = 17,

DNS_RCODE_BADTIME = 18,

DNS_RCODE_BADMODE = 19,

DNS_RCODE_BADNAME = 20,

DNS_RCODE_BADALG = 21,

DNS_RCODE_BADTRUNC = 22,

_DNS_RCODE_MAX_DEFINED

};

const char* dns_rcode_to_string(int i) _const_;

int dns_rcode_from_string(const char *s) _pure_;

const char* dns_protocol_to_string(DnsProtocol p) _const_;

DnsProtocol dns_protocol_from_string(const char *s) _pure_;

#define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) })

#define LLMNR_MULTICAST_IPV6_ADDRESS ((struct in6_addr) { .s6_addr = { 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x03 } })

#define MDNS_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 251U) })

#define MDNS_MULTICAST_IPV6_ADDRESS ((struct in6_addr) { .s6_addr = { 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfb } })

static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol, int family, bool authenticated) {

uint64_t f;

/* Converts a protocol + family into a flags field as used in queries and responses */

f = authenticated ? SD_RESOLVED_AUTHENTICATED : 0;

switch (protocol) {

case DNS_PROTOCOL_DNS:

return f|SD_RESOLVED_DNS;

case DNS_PROTOCOL_LLMNR:

return f|(family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4);

case DNS_PROTOCOL_MDNS:

return family == AF_INET6 ? SD_RESOLVED_MDNS_IPV6 : SD_RESOLVED_MDNS_IPV4;

default:

break;

}

return 0;

}