Adding upstream version 247.3.upstream/247.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 302 insertions, 0 deletions

diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h
new file mode 100644
index 0000000..7d6ee2b
--- /dev/null
+++ b/src/resolve/resolved-dns-packet.h
@@ -0,0 +1,302 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#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))
+
+/* 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 0xFFFFu
+
+/* The default size to use for allocation when we don't know how large
+ * the packet will turn out to be. */
+#define DNS_PACKET_SIZE_START 512u
+
+/* RFC 1035 say 512 is the maximum, for classic unicast DNS */
+#define DNS_PACKET_UNICAST_SIZE_MAX 512u
+
+/* With EDNS0 we can use larger packets, default to 4096, which is what is commonly used */
+#define DNS_PACKET_UNICAST_SIZE_LARGE_MAX 4096u
+
+struct DnsPacket {
+        unsigned n_ref;
+        DnsProtocol protocol;
+        size_t size, allocated, rindex, max_size;
+        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)
+
+#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 size for replies, or the DNS default if there's nothing defined. */
+
+        if (p->ipproto == IPPROTO_TCP) /* we ignore EDNS(0) size data on TCP, like everybody else */
+                return DNS_PACKET_SIZE_MAX;
+
+        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)
+#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 min_alloc_dsize, size_t max_size);
+int dns_packet_new_query(DnsPacket **p, DnsProtocol protocol, size_t min_alloc_dsize, 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, const DnsAnswerFlags flags, size_t *start);
+int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAnswerFlags flags, size_t *start, size_t *rdata_start);
+int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, bool include_rfc6975, 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);
+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
+         * 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,
+        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_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_;
+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 } })
+
+extern const struct hash_ops dns_packet_hash_ops;
+
+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 f|(family == AF_INET6 ? SD_RESOLVED_MDNS_IPV6 : SD_RESOLVED_MDNS_IPV4);
+
+        default:
+                return f;
+        }
+}
+
+static inline size_t dns_packet_size_max(DnsPacket *p) {
+        assert(p);
+
+        /* Why not insist on a fully initialized max_size during DnsPacket construction? Well, this way it's easy to
+         * allocate a transient, throw-away DnsPacket on the stack by simple zero initialization, without having to
+         * deal with explicit field initialization. */
+
+        return p->max_size != 0 ? p->max_size : DNS_PACKET_SIZE_MAX;
+}