src/resolve/resolved-dns-packet.h - systemd-stable - Rivoreo Source Code Repositories

 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

 #pragma once

 /***
   This file is part of systemd.

   Copyright 2014 Lennart Poettering

   systemd is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation; either version 2.1 of the License, or
   (at your option) any later version.

   systemd is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  ***/

 #include <netinet/udp.h>
 #include <netinet/ip.h>

 #include "macro.h"
 #include "sparse-endian.h"
 #include "hashmap.h"
 #include "in-addr-util.h"

 typedef struct DnsPacketHeader DnsPacketHeader;
 typedef struct DnsPacket DnsPacket;

 #include "resolved-dns-rr.h"
 #include "resolved-dns-question.h"
 #include "resolved-dns-answer.h"
 #include "resolved-def.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))

 /* The various DNS protocols deviate in how large a packet can grow,
    but the TCP transport has a 16bit size field, hence that appears to
    be the absolute maximum. */
 #define DNS_PACKET_SIZE_MAX 0xFFFF

 /* RFC 1035 say 512 is the maximum, for classic unicast DNS */
 #define DNS_PACKET_UNICAST_SIZE_MAX 512

 #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 */

         /* Parsed data */
         DnsQuestion *question;
         DnsAnswer *answer;

         /* Packet reception metadata */
         int ifindex;
         int family, ipproto;
         union in_addr_union sender, destination;
         uint16_t sender_port, destination_port;
         uint32_t ttl;

         bool extracted;
         bool refuse_compression;
 };

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

 /* LLMNR defines some bits differently */
 #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);

 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_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_label(DnsPacket *p, const char *s, size_t l, size_t *start);
 int dns_packet_append_name(DnsPacket *p, const char *name,
                            bool allow_compression, 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);

 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_name(DnsPacket *p, char **ret,
                          bool allow_compression, size_t *start);
 int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start);
 int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, 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);

 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 DNSKEY_FLAG_ZONE_KEY (1u << 8)
 #define DNSKEY_FLAG_SEP      (1u << 0)

 static inline uint16_t dnskey_to_flags(const DnsResourceRecord *rr) {
         return (rr->dnskey.zone_key_flag * DNSKEY_FLAG_ZONE_KEY |
                 rr->dnskey.sep_flag * DNSKEY_FLAG_SEP);
 }

 /* http://tools.ietf.org/html/rfc4034#appendix-A.1 */
 enum {
         DNSSEC_ALGORITHM_RSAMD5 = 1,
         DNSSEC_ALGORITHM_DH,
         DNSSEC_ALGORITHM_DSA,
         DNSSEC_ALGORITHM_ECC,
         DNSSEC_ALGORITHM_RSASHA1,
         DNSSEC_ALGORITHM_DSA_NSEC3_SHA1,
         DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
         DNSSEC_ALGORITHM_INDIRECT = 252,
         DNSSEC_ALGORITHM_PRIVATEDNS,
         DNSSEC_ALGORITHM_PRIVATEOID,
         _DNSSEC_ALGORITHM_MAX_DEFINED
 };

 const char* dnssec_algorithm_to_string(int i) _const_;
 int dnssec_algorithm_from_string(const char *s) _pure_;

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

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

         switch (protocol) {
         case DNS_PROTOCOL_DNS:
                 return SD_RESOLVED_DNS;

         case DNS_PROTOCOL_LLMNR:
                 return family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4;

         default:
                 break;
         }

         return 0;
 }
	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/

	#pragma once

	/***
	This file is part of systemd.

	Copyright 2014 Lennart Poettering

	systemd is free software; you can redistribute it and/or modify it
	under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation; either version 2.1 of the License, or
	(at your option) any later version.

	systemd is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	***/

	#include <netinet/udp.h>
	#include <netinet/ip.h>

	#include "macro.h"
	#include "sparse-endian.h"
	#include "hashmap.h"
	#include "in-addr-util.h"

	typedef struct DnsPacketHeader DnsPacketHeader;
	typedef struct DnsPacket DnsPacket;

	#include "resolved-dns-rr.h"
	#include "resolved-dns-question.h"
	#include "resolved-dns-answer.h"
	#include "resolved-def.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))

	/* The various DNS protocols deviate in how large a packet can grow,
	but the TCP transport has a 16bit size field, hence that appears to
	be the absolute maximum. */
	#define DNS_PACKET_SIZE_MAX 0xFFFF

	/* RFC 1035 say 512 is the maximum, for classic unicast DNS */
	#define DNS_PACKET_UNICAST_SIZE_MAX 512

	#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 */

	/* Parsed data */
	DnsQuestion *question;
	DnsAnswer *answer;

	/* Packet reception metadata */
	int ifindex;
	int family, ipproto;
	union in_addr_union sender, destination;
	uint16_t sender_port, destination_port;
	uint32_t ttl;

	bool extracted;
	bool refuse_compression;
	};

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

	/* LLMNR defines some bits differently */
	#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);

	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_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_label(DnsPacket p, const char s, size_t l, size_t *start);
	int dns_packet_append_name(DnsPacket p, const char name,
	bool allow_compression, 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);

	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_name(DnsPacket p, char *ret,
	bool allow_compression, size_t *start);
	int dns_packet_read_key(DnsPacket p, DnsResourceKey ret, size_t start);
	int dns_packet_read_rr(DnsPacket p, DnsResourceRecord ret, 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);

	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 DNSKEY_FLAG_ZONE_KEY (1u << 8)
	#define DNSKEY_FLAG_SEP (1u << 0)

	static inline uint16_t dnskey_to_flags(const DnsResourceRecord *rr) {
	return (rr->dnskey.zone_key_flag * DNSKEY_FLAG_ZONE_KEY \|
	rr->dnskey.sep_flag * DNSKEY_FLAG_SEP);
	}

	/* http://tools.ietf.org/html/rfc4034#appendix-A.1 */
	enum {
	DNSSEC_ALGORITHM_RSAMD5 = 1,
	DNSSEC_ALGORITHM_DH,
	DNSSEC_ALGORITHM_DSA,
	DNSSEC_ALGORITHM_ECC,
	DNSSEC_ALGORITHM_RSASHA1,
	DNSSEC_ALGORITHM_DSA_NSEC3_SHA1,
	DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
	DNSSEC_ALGORITHM_INDIRECT = 252,
	DNSSEC_ALGORITHM_PRIVATEDNS,
	DNSSEC_ALGORITHM_PRIVATEOID,
	_DNSSEC_ALGORITHM_MAX_DEFINED
	};

	const char* dnssec_algorithm_to_string(int i) _const_;
	int dnssec_algorithm_from_string(const char *s) _pure_;

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

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

	switch (protocol) {
	case DNS_PROTOCOL_DNS:
	return SD_RESOLVED_DNS;

	case DNS_PROTOCOL_LLMNR:
	return family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4;

	default:
	break;
	}

	return 0;
	}