diff options
Diffstat (limited to 'src/resolve/resolved-dns-packet.h')
| -rw-r--r-- | src/resolve/resolved-dns-packet.h | 175 |
1 files changed, 115 insertions, 60 deletions
diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h index 58559c85df..054dc88a85 100644 --- a/src/resolve/resolved-dns-packet.h +++ b/src/resolve/resolved-dns-packet.h @@ -1,5 +1,3 @@ -/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ - #pragma once /*** @@ -21,21 +19,21 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ -#include <netinet/udp.h> #include <netinet/ip.h> +#include <netinet/udp.h> -#include "macro.h" -#include "sparse-endian.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-dns-rr.h" -#include "resolved-dns-question.h" -#include "resolved-dns-answer.h" #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, @@ -65,6 +63,9 @@ struct DnsPacketHeader { /* RFC 1035 say 512 is the maximum, for classic unicast DNS */ #define DNS_PACKET_UNICAST_SIZE_MAX 512 +/* With EDNS0 we can use larger packets, default to 4096, which is what is commonly used */ +#define DNS_PACKET_UNICAST_SIZE_LARGE_MAX 4096 + #define DNS_PACKET_SIZE_START 512 struct DnsPacket { @@ -73,19 +74,27 @@ struct DnsPacket { 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 meta data */ + /* 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; + /* 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) { @@ -108,7 +117,46 @@ static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) { #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) + +#define DNS_PACKET_FLAG_TC (UINT16_C(1) << 9) + +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) & 0xF); +} + +static inline uint16_t DNS_PACKET_PAYLOAD_SIZE_MAX(DnsPacket *p) { + + /* Returns the advertised maximum datagram size for replies, or the DNS default if there's nothing defined. */ + + if (p->opt) + return MAX(DNS_PACKET_UNICAST_SIZE_MAX, p->opt->key->class); + + return DNS_PACKET_UNICAST_SIZE_MAX; +} + +static inline bool DNS_PACKET_DO(DnsPacket *p) { + if (!p->opt) + return false; + + return !!(p->opt->ttl & (1U << 15)); +} + +static inline bool DNS_PACKET_VERSION_SUPPORTED(DnsPacket *p) { + /* Returns true if this packet is in a version we support. Which means either non-EDNS or EDNS(0), but not EDNS + * of any newer versions */ + + if (!p->opt) + return true; + + return DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(p->opt); +} /* LLMNR defines some bits differently */ #define DNS_PACKET_LLMNR_C(p) DNS_PACKET_AA(p) @@ -120,15 +168,15 @@ static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) { #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) | \ - ((uint16_t) !!tc << 9) | \ - ((uint16_t) !!rd << 8) | \ - ((uint16_t) !!ra << 7) | \ - ((uint16_t) !!ad << 5) | \ - ((uint16_t) !!cd << 4) | \ - ((uint16_t) (rcode & 15))) + (((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 @@ -138,7 +186,9 @@ static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket *p) { } int dns_packet_new(DnsPacket **p, DnsProtocol protocol, size_t mtu); -int dns_packet_new_query(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); @@ -149,16 +199,24 @@ 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_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_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); +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, int rcode, size_t *start); +int dns_packet_append_question(DnsPacket *p, DnsQuestion *q); +int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a); + +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); @@ -166,16 +224,25 @@ 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); +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 + * assumption, that it's coming from a locally DNS forwarder + * or server, that is caching on its own. */ + + return in_addr_is_localhost(p->family, &p->sender) == 0; +} + +/* https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6 */ enum { DNS_RCODE_SUCCESS = 0, DNS_RCODE_FORMERR = 1, @@ -196,7 +263,9 @@ enum { DNS_RCODE_BADNAME = 20, DNS_RCODE_BADALG = 21, DNS_RCODE_BADTRUNC = 22, - _DNS_RCODE_MAX_DEFINED + DNS_RCODE_BADCOOKIE = 23, + _DNS_RCODE_MAX_DEFINED, + _DNS_RCODE_MAX = 4095 /* 4 bit rcode in the header plus 8 bit rcode in OPT, makes 12 bit */ }; const char* dns_rcode_to_string(int i) _const_; @@ -208,41 +277,27 @@ 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); -} +#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 } }) -/* 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 -}; +static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol, int family, bool authenticated) { + uint64_t f; -const char* dnssec_algorithm_to_string(int i) _const_; -int dnssec_algorithm_from_string(const char *s) _pure_; + /* Converts a protocol + family into a flags field as used in queries and responses */ -static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol, int family) { + f = authenticated ? SD_RESOLVED_AUTHENTICATED : 0; - /* Converts a protocol + family into a flags field as used in queries */ + switch (protocol) { + case DNS_PROTOCOL_DNS: + return f|SD_RESOLVED_DNS; - if (protocol == DNS_PROTOCOL_DNS) - return SD_RESOLVED_DNS; + case DNS_PROTOCOL_LLMNR: + return f|(family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4); - if (protocol == DNS_PROTOCOL_LLMNR) - return family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4; + case DNS_PROTOCOL_MDNS: + return f|(family == AF_INET6 ? SD_RESOLVED_MDNS_IPV6 : SD_RESOLVED_MDNS_IPV4); - return 0; + default: + return f; + } } |