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Commit | Line | Data |
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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
74b2466e LP |
2 | #pragma once |
3 | ||
a0166609 | 4 | #include <netinet/ip.h> |
4565863f | 5 | #include <netinet/ip6.h> |
71d35b6b | 6 | #include <netinet/udp.h> |
74b2466e | 7 | |
74b2466e | 8 | #include "hashmap.h" |
7e8e0422 | 9 | #include "in-addr-util.h" |
71d35b6b TA |
10 | #include "macro.h" |
11 | #include "sparse-endian.h" | |
7e8e0422 LP |
12 | |
13 | typedef struct DnsPacketHeader DnsPacketHeader; | |
14 | typedef struct DnsPacket DnsPacket; | |
15 | ||
51323288 | 16 | #include "resolved-def.h" |
71d35b6b TA |
17 | #include "resolved-dns-answer.h" |
18 | #include "resolved-dns-question.h" | |
19 | #include "resolved-dns-rr.h" | |
74b2466e | 20 | |
1716f6dc LP |
21 | typedef enum DnsProtocol { |
22 | DNS_PROTOCOL_DNS, | |
23 | DNS_PROTOCOL_MDNS, | |
24 | DNS_PROTOCOL_LLMNR, | |
25 | _DNS_PROTOCOL_MAX, | |
2d93c20e | 26 | _DNS_PROTOCOL_INVALID = -EINVAL, |
1716f6dc LP |
27 | } DnsProtocol; |
28 | ||
74b2466e LP |
29 | struct DnsPacketHeader { |
30 | uint16_t id; | |
31 | be16_t flags; | |
32 | be16_t qdcount; | |
33 | be16_t ancount; | |
34 | be16_t nscount; | |
35 | be16_t arcount; | |
4565863f | 36 | } _packed_; |
74b2466e LP |
37 | |
38 | #define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader) | |
4565863f LP |
39 | #define UDP4_PACKET_HEADER_SIZE (sizeof(struct iphdr) + sizeof(struct udphdr)) |
40 | #define UDP6_PACKET_HEADER_SIZE (sizeof(struct ip6_hdr) + sizeof(struct udphdr)) | |
41 | ||
42 | assert_cc(sizeof(struct ip6_hdr) == 40); | |
43 | assert_cc(sizeof(struct iphdr) == 20); | |
44 | assert_cc(sizeof(struct udphdr) == 8); | |
45 | assert_cc(sizeof(DnsPacketHeader) == 12); | |
c73ce96b | 46 | |
4565863f LP |
47 | /* The various DNS protocols deviate in how large a packet can grow, but the TCP transport has a 16bit size |
48 | * field, hence that appears to be the absolute maximum. */ | |
64a21fda | 49 | #define DNS_PACKET_SIZE_MAX 0xFFFFu |
e1c95994 | 50 | |
86d06089 ZJS |
51 | /* The default size to use for allocation when we don't know how large |
52 | * the packet will turn out to be. */ | |
53 | #define DNS_PACKET_SIZE_START 512u | |
54 | ||
e1c95994 | 55 | /* RFC 1035 say 512 is the maximum, for classic unicast DNS */ |
64a21fda | 56 | #define DNS_PACKET_UNICAST_SIZE_MAX 512u |
e1c95994 | 57 | |
d74fb368 | 58 | /* With EDNS0 we can use larger packets, default to 4096, which is what is commonly used */ |
64a21fda | 59 | #define DNS_PACKET_UNICAST_SIZE_LARGE_MAX 4096u |
d74fb368 | 60 | |
74b2466e | 61 | struct DnsPacket { |
cf4b2f99 | 62 | unsigned n_ref; |
1716f6dc | 63 | DnsProtocol protocol; |
20a001bd | 64 | size_t size, allocated, rindex, max_size, fragsize; |
faa133f3 | 65 | void *_data; /* don't access directly, use DNS_PACKET_DATA()! */ |
74b2466e | 66 | Hashmap *names; /* For name compression */ |
519ef046 | 67 | size_t opt_start, opt_size; |
faa133f3 LP |
68 | |
69 | /* Parsed data */ | |
70 | DnsQuestion *question; | |
71 | DnsAnswer *answer; | |
d75acfb0 | 72 | DnsResourceRecord *opt; |
1716f6dc | 73 | |
421b1f0a ZJS |
74 | /* For support of truncated packets */ |
75 | DnsPacket *more; | |
76 | ||
dc61b7e4 | 77 | /* Packet reception metadata */ |
421b1f0a | 78 | usec_t timestamp; /* CLOCK_BOOTTIME (or CLOCK_MONOTONIC if the former doesn't exist) */ |
1716f6dc | 79 | int ifindex; |
623a4c97 | 80 | int family, ipproto; |
1716f6dc | 81 | union in_addr_union sender, destination; |
623a4c97 | 82 | uint16_t sender_port, destination_port; |
0dd25fb9 | 83 | uint32_t ttl; |
a4076574 | 84 | |
421b1f0a ZJS |
85 | bool on_stack; |
86 | bool extracted; | |
87 | bool refuse_compression; | |
88 | bool canonical_form; | |
9c491563 | 89 | |
421b1f0a | 90 | /* Note: fields should be ordered to minimize alignment gaps. Use pahole! */ |
74b2466e LP |
91 | }; |
92 | ||
7130db91 | 93 | static inline uint8_t* DNS_PACKET_DATA(const DnsPacket *p) { |
74b2466e LP |
94 | if (_unlikely_(!p)) |
95 | return NULL; | |
96 | ||
faa133f3 LP |
97 | if (p->_data) |
98 | return p->_data; | |
74b2466e LP |
99 | |
100 | return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket)); | |
101 | } | |
102 | ||
103 | #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p)) | |
3cb10d3a LP |
104 | #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id |
105 | #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1) | |
106 | #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15) | |
8b757a38 | 107 | #define DNS_PACKET_AA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 10) & 1) |
ad867662 | 108 | #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1) |
8b757a38 DM |
109 | #define DNS_PACKET_RD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 8) & 1) |
110 | #define DNS_PACKET_RA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 7) & 1) | |
111 | #define DNS_PACKET_AD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 5) & 1) | |
112 | #define DNS_PACKET_CD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 4) & 1) | |
f3abbe25 | 113 | |
b30bf55d LP |
114 | #define DNS_PACKET_FLAG_TC (UINT16_C(1) << 9) |
115 | ||
f3abbe25 LP |
116 | static inline uint16_t DNS_PACKET_RCODE(DnsPacket *p) { |
117 | uint16_t rcode; | |
118 | ||
119 | if (p->opt) | |
120 | rcode = (uint16_t) (p->opt->ttl >> 24); | |
121 | else | |
122 | rcode = 0; | |
123 | ||
b30bf55d LP |
124 | return rcode | (be16toh(DNS_PACKET_HEADER(p)->flags) & 0xF); |
125 | } | |
126 | ||
127 | static inline uint16_t DNS_PACKET_PAYLOAD_SIZE_MAX(DnsPacket *p) { | |
128 | ||
e6eed944 | 129 | /* Returns the advertised maximum size for replies, or the DNS default if there's nothing defined. */ |
b30bf55d | 130 | |
acd74d61 LP |
131 | if (p->ipproto == IPPROTO_TCP) /* we ignore EDNS(0) size data on TCP, like everybody else */ |
132 | return DNS_PACKET_SIZE_MAX; | |
133 | ||
b30bf55d LP |
134 | if (p->opt) |
135 | return MAX(DNS_PACKET_UNICAST_SIZE_MAX, p->opt->key->class); | |
136 | ||
137 | return DNS_PACKET_UNICAST_SIZE_MAX; | |
138 | } | |
139 | ||
140 | static inline bool DNS_PACKET_DO(DnsPacket *p) { | |
141 | if (!p->opt) | |
142 | return false; | |
143 | ||
144 | return !!(p->opt->ttl & (1U << 15)); | |
145 | } | |
146 | ||
147 | static inline bool DNS_PACKET_VERSION_SUPPORTED(DnsPacket *p) { | |
148 | /* Returns true if this packet is in a version we support. Which means either non-EDNS or EDNS(0), but not EDNS | |
149 | * of any newer versions */ | |
150 | ||
151 | if (!p->opt) | |
152 | return true; | |
153 | ||
154 | return DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(p->opt); | |
f3abbe25 | 155 | } |
8b757a38 | 156 | |
acbf761b LP |
157 | static inline bool DNS_PACKET_IS_FRAGMENTED(DnsPacket *p) { |
158 | assert(p); | |
159 | ||
160 | /* For ingress packets: was this packet fragmented according to our knowledge? */ | |
161 | ||
162 | return p->fragsize != 0; | |
163 | } | |
164 | ||
8b757a38 DM |
165 | /* LLMNR defines some bits differently */ |
166 | #define DNS_PACKET_LLMNR_C(p) DNS_PACKET_AA(p) | |
167 | #define DNS_PACKET_LLMNR_T(p) DNS_PACKET_RD(p) | |
168 | ||
3cb10d3a LP |
169 | #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount) |
170 | #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount) | |
171 | #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount) | |
172 | #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount) | |
173 | ||
174 | #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \ | |
f0258e47 LP |
175 | (((uint16_t) !!(qr) << 15) | \ |
176 | ((uint16_t) ((opcode) & 15) << 11) | \ | |
177 | ((uint16_t) !!(aa) << 10) | /* on LLMNR: c */ \ | |
178 | ((uint16_t) !!(tc) << 9) | \ | |
179 | ((uint16_t) !!(rd) << 8) | /* on LLMNR: t */ \ | |
180 | ((uint16_t) !!(ra) << 7) | \ | |
181 | ((uint16_t) !!(ad) << 5) | \ | |
182 | ((uint16_t) !!(cd) << 4) | \ | |
183 | ((uint16_t) ((rcode) & 15))) | |
3cb10d3a | 184 | |
322345fd LP |
185 | static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket *p) { |
186 | return | |
187 | (unsigned) DNS_PACKET_ANCOUNT(p) + | |
188 | (unsigned) DNS_PACKET_NSCOUNT(p) + | |
189 | (unsigned) DNS_PACKET_ARCOUNT(p); | |
190 | } | |
74b2466e | 191 | |
51027656 | 192 | int dns_packet_new(DnsPacket **p, DnsProtocol protocol, size_t min_alloc_dsize, size_t max_size); |
46a58596 | 193 | int dns_packet_new_query(DnsPacket **p, DnsProtocol protocol, size_t min_alloc_dsize, bool dnssec_checking_disabled); |
74b2466e | 194 | |
1a6cd020 LP |
195 | int dns_packet_dup(DnsPacket **ret, DnsPacket *p); |
196 | ||
dbfbb6e7 DM |
197 | void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated); |
198 | ||
74b2466e LP |
199 | DnsPacket *dns_packet_ref(DnsPacket *p); |
200 | DnsPacket *dns_packet_unref(DnsPacket *p); | |
201 | ||
202 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref); | |
203 | ||
204 | int dns_packet_validate(DnsPacket *p); | |
205 | int dns_packet_validate_reply(DnsPacket *p); | |
623a4c97 | 206 | int dns_packet_validate_query(DnsPacket *p); |
74b2466e | 207 | |
8af5b883 LP |
208 | int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key); |
209 | ||
623a4c97 | 210 | int dns_packet_append_blob(DnsPacket *p, const void *d, size_t sz, size_t *start); |
74b2466e LP |
211 | int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start); |
212 | int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start); | |
623a4c97 | 213 | int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start); |
74b2466e | 214 | int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start); |
2001c805 | 215 | int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start); |
a3db237b LP |
216 | int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, bool canonical_candidate, size_t *start); |
217 | int dns_packet_append_name(DnsPacket *p, const char *name, bool allow_compression, bool canonical_candidate, size_t *start); | |
58ab31d5 DR |
218 | int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, const DnsAnswerFlags flags, size_t *start); |
219 | int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAnswerFlags flags, size_t *start, size_t *rdata_start); | |
4a6eb824 | 220 | int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, bool include_rfc6975, const char *nsid, int rcode, size_t *ret_start); |
f471bc11 | 221 | int dns_packet_append_question(DnsPacket *p, DnsQuestion *q); |
6f76e68a | 222 | int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a, unsigned *completed); |
74b2466e | 223 | |
93748b26 | 224 | int dns_packet_patch_max_udp_size(DnsPacket *p, uint16_t max_udp_size); |
81b4d94d | 225 | int dns_packet_patch_ttls(DnsPacket *p, usec_t timestamp); |
74b2466e | 226 | |
9c5e12a4 | 227 | void dns_packet_truncate(DnsPacket *p, size_t sz); |
519ef046 | 228 | int dns_packet_truncate_opt(DnsPacket *p); |
9c5e12a4 | 229 | |
74b2466e | 230 | int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start); |
623a4c97 | 231 | int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start); |
74b2466e LP |
232 | int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start); |
233 | int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start); | |
234 | int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start); | |
235 | int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start); | |
2001c805 LP |
236 | int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start); |
237 | int dns_packet_read_name(DnsPacket *p, char **ret, bool allow_compression, size_t *start); | |
82d39576 | 238 | int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush_or_qu, size_t *start); |
d2579eec | 239 | int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start); |
74b2466e | 240 | |
8ba9fd9c LP |
241 | void dns_packet_rewind(DnsPacket *p, size_t idx); |
242 | ||
74b2466e | 243 | int dns_packet_skip_question(DnsPacket *p); |
faa133f3 | 244 | int dns_packet_extract(DnsPacket *p); |
74b2466e | 245 | |
a9fd8837 LP |
246 | bool dns_packet_equal(const DnsPacket *a, const DnsPacket *b); |
247 | ||
4a6eb824 LP |
248 | int dns_packet_has_nsid_request(DnsPacket *p); |
249 | ||
f3abbe25 | 250 | /* https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6 */ |
74b2466e LP |
251 | enum { |
252 | DNS_RCODE_SUCCESS = 0, | |
253 | DNS_RCODE_FORMERR = 1, | |
254 | DNS_RCODE_SERVFAIL = 2, | |
255 | DNS_RCODE_NXDOMAIN = 3, | |
256 | DNS_RCODE_NOTIMP = 4, | |
257 | DNS_RCODE_REFUSED = 5, | |
258 | DNS_RCODE_YXDOMAIN = 6, | |
259 | DNS_RCODE_YXRRSET = 7, | |
260 | DNS_RCODE_NXRRSET = 8, | |
261 | DNS_RCODE_NOTAUTH = 9, | |
262 | DNS_RCODE_NOTZONE = 10, | |
263 | DNS_RCODE_BADVERS = 16, | |
264 | DNS_RCODE_BADSIG = 16, /* duplicate value! */ | |
265 | DNS_RCODE_BADKEY = 17, | |
266 | DNS_RCODE_BADTIME = 18, | |
267 | DNS_RCODE_BADMODE = 19, | |
268 | DNS_RCODE_BADNAME = 20, | |
269 | DNS_RCODE_BADALG = 21, | |
270 | DNS_RCODE_BADTRUNC = 22, | |
6f21e066 | 271 | DNS_RCODE_BADCOOKIE = 23, |
f2ed4c69 LP |
272 | _DNS_RCODE_MAX_DEFINED, |
273 | _DNS_RCODE_MAX = 4095 /* 4 bit rcode in the header plus 8 bit rcode in OPT, makes 12 bit */ | |
74b2466e LP |
274 | }; |
275 | ||
276 | const char* dns_rcode_to_string(int i) _const_; | |
277 | int dns_rcode_from_string(const char *s) _pure_; | |
1716f6dc LP |
278 | |
279 | const char* dns_protocol_to_string(DnsProtocol p) _const_; | |
280 | DnsProtocol dns_protocol_from_string(const char *s) _pure_; | |
281 | ||
282 | #define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) }) | |
283 | #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 } }) | |
8db0d2f5 | 284 | |
0db4c90a | 285 | #define MDNS_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 251U) }) |
b6c5d46b | 286 | #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 } }) |
0db4c90a | 287 | |
98767d75 IT |
288 | extern const struct hash_ops dns_packet_hash_ops; |
289 | ||
43fc4baa LP |
290 | static inline uint64_t SD_RESOLVED_FLAGS_MAKE( |
291 | DnsProtocol protocol, | |
292 | int family, | |
293 | bool authenticated, | |
294 | bool confidential) { | |
931851e8 | 295 | uint64_t f; |
51323288 | 296 | |
931851e8 LP |
297 | /* Converts a protocol + family into a flags field as used in queries and responses */ |
298 | ||
43fc4baa LP |
299 | f = (authenticated ? SD_RESOLVED_AUTHENTICATED : 0) | |
300 | (confidential ? SD_RESOLVED_CONFIDENTIAL : 0); | |
51323288 | 301 | |
106784eb DM |
302 | switch (protocol) { |
303 | case DNS_PROTOCOL_DNS: | |
931851e8 | 304 | return f|SD_RESOLVED_DNS; |
51323288 | 305 | |
106784eb | 306 | case DNS_PROTOCOL_LLMNR: |
931851e8 | 307 | return f|(family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4); |
51323288 | 308 | |
4e5bf5e1 | 309 | case DNS_PROTOCOL_MDNS: |
12e1893a | 310 | return f|(family == AF_INET6 ? SD_RESOLVED_MDNS_IPV6 : SD_RESOLVED_MDNS_IPV4); |
4e5bf5e1 | 311 | |
106784eb | 312 | default: |
12e1893a | 313 | return f; |
106784eb | 314 | } |
51323288 | 315 | } |
51027656 LP |
316 | |
317 | static inline size_t dns_packet_size_max(DnsPacket *p) { | |
318 | assert(p); | |
319 | ||
320 | /* Why not insist on a fully initialized max_size during DnsPacket construction? Well, this way it's easy to | |
321 | * allocate a transient, throw-away DnsPacket on the stack by simple zero initialization, without having to | |
322 | * deal with explicit field initialization. */ | |
323 | ||
324 | return p->max_size != 0 ? p->max_size : DNS_PACKET_SIZE_MAX; | |
325 | } | |
4565863f LP |
326 | |
327 | static inline size_t udp_header_size(int af) { | |
328 | ||
329 | switch (af) { | |
330 | case AF_INET: | |
331 | return UDP4_PACKET_HEADER_SIZE; | |
332 | case AF_INET6: | |
333 | return UDP6_PACKET_HEADER_SIZE; | |
334 | default: | |
335 | assert_not_reached("Unexpected address family"); | |
336 | } | |
337 | } | |
acbf761b LP |
338 | |
339 | size_t dns_packet_size_unfragmented(DnsPacket *p); |