1 //! This module exposes utilities for building DNSSEC proofs by directly querying a recursive
8 #[cfg(feature = "std")]
9 use std::net::{SocketAddr, TcpStream};
10 #[cfg(feature = "std")]
11 use std::io::{Read, Write, Error, ErrorKind};
13 #[cfg(feature = "tokio")]
14 use tokio_crate::net::TcpStream as TokioTcpStream;
15 #[cfg(feature = "tokio")]
16 use tokio_crate::io::{AsyncReadExt, AsyncWriteExt};
21 // In testing use a rather small buffer to ensure we hit the allocation paths sometimes. In
22 // production, we should generally never actually need to go to heap as DNS messages are rarely
23 // larger than a KiB or two.
24 #[cfg(any(test, fuzzing))]
25 const STACK_BUF_LIMIT: u16 = 32;
26 #[cfg(not(any(test, fuzzing)))]
27 const STACK_BUF_LIMIT: u16 = 2048;
29 /// A buffer for storing queries and responses.
30 #[derive(Clone, PartialEq, Eq)]
32 buf: [u8; STACK_BUF_LIMIT as usize],
37 /// Generates a new buffer of the given length, consisting of all zeros.
38 pub fn new_zeroed(len: u16) -> Self {
39 let heap_buf = if len > STACK_BUF_LIMIT { vec![0; len as usize] } else { Vec::new() };
41 buf: [0; STACK_BUF_LIMIT as usize],
46 /// Extends the size of this buffer by appending the given slice.
48 /// If the total length of this buffer exceeds [`u16::MAX`] after appending, the buffer's state
49 /// is undefined, however pushing data beyond [`u16::MAX`] will not panic.
50 pub fn extend_from_slice(&mut self, sl: &[u8]) {
51 let new_len = self.len.saturating_add(sl.len() as u16);
52 let was_heap = self.len > STACK_BUF_LIMIT;
53 let is_heap = new_len > STACK_BUF_LIMIT;
54 if was_heap != is_heap {
55 self.heap_buf = vec![0; new_len as usize];
56 self.heap_buf[..self.len as usize].copy_from_slice(&self.buf[..self.len as usize]);
58 let target = if is_heap {
59 self.heap_buf.resize(new_len as usize, 0);
60 &mut self.heap_buf[self.len as usize..]
62 &mut self.buf[self.len as usize..new_len as usize]
64 target.copy_from_slice(sl);
67 /// Converts this query into its bytes on the heap
68 pub fn into_vec(self) -> Vec<u8> {
69 if self.len > STACK_BUF_LIMIT {
72 self.buf[..self.len as usize].to_vec()
76 impl ops::Deref for QueryBuf {
78 fn deref(&self) -> &[u8] {
79 if self.len > STACK_BUF_LIMIT {
82 &self.buf[..self.len as usize]
86 impl ops::DerefMut for QueryBuf {
87 fn deref_mut(&mut self) -> &mut [u8] {
88 if self.len > STACK_BUF_LIMIT {
91 &mut self.buf[..self.len as usize]
96 // We don't care about transaction IDs as we're only going to accept signed data.
97 // Further, if we're querying over DoH, the RFC says we SHOULD use a transaction ID of 0 here.
100 fn build_query(domain: &Name, ty: u16) -> QueryBuf {
101 let mut query = QueryBuf::new_zeroed(0);
102 query.extend_from_slice(&TXID.to_be_bytes());
103 query.extend_from_slice(&[0x01, 0x20]); // Flags: Recursive, Authenticated Data
104 query.extend_from_slice(&[0, 1, 0, 0, 0, 0, 0, 1]); // One question, One additional
105 write_name(&mut query, domain);
106 query.extend_from_slice(&ty.to_be_bytes());
107 query.extend_from_slice(&1u16.to_be_bytes()); // INternet class
108 query.extend_from_slice(&[0, 0, 0x29]); // . OPT
109 query.extend_from_slice(&0u16.to_be_bytes()); // 0 UDP payload size
110 query.extend_from_slice(&[0, 0]); // EDNS version 0
111 query.extend_from_slice(&0x8000u16.to_be_bytes()); // Accept DNSSEC RRs
112 query.extend_from_slice(&0u16.to_be_bytes()); // No additional data
117 /// Read some input and parse it as if it came from a server, for fuzzing.
118 pub fn fuzz_response(response: &[u8]) {
119 let (mut proof, mut names) = (Vec::new(), Vec::new());
120 let _ = handle_response(response, &mut proof, &mut names);
123 fn handle_response(resp: &[u8], proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, ()> {
124 let mut read: &[u8] = resp;
125 if read_u16(&mut read)? != TXID { return Err(()); }
126 // 2 byte transaction ID
127 let flags = read_u16(&mut read)?;
128 if flags & 0b1000_0000_0000_0000 == 0 {
131 if flags & 0b0111_1010_0000_0111 != 0 {
134 if flags & 0b10_0000 == 0 {
137 let questions = read_u16(&mut read)?;
138 if questions != 1 { return Err(()); }
139 let answers = read_u16(&mut read)?;
140 if answers == 0 { return Err(()); }
141 let _authorities = read_u16(&mut read)?;
142 let _additional = read_u16(&mut read)?;
144 for _ in 0..questions {
145 read_wire_packet_name(&mut read, resp)?;
146 read_u16(&mut read)?; // type
147 read_u16(&mut read)?; // class
150 // Only read the answers (skip authorities and additional) as that's all we care about.
151 let mut min_ttl = u32::MAX;
152 for _ in 0..answers {
153 let (rr, ttl) = parse_wire_packet_rr(&mut read, &resp)?;
154 write_rr(&rr, ttl, proof);
155 min_ttl = cmp::min(min_ttl, ttl);
156 if let RR::RRSig(rrsig) = rr { rrsig_key_names.push(rrsig.key_name); }
162 /// Read a stream of responses and handle them it as if they came from a server, for fuzzing.
163 pub fn fuzz_proof_builder(mut response_stream: &[u8]) {
164 let (mut builder, _) = ProofBuilder::new(&"example.com.".try_into().unwrap(), Txt::TYPE);
165 while builder.awaiting_responses() {
166 let len = if let Ok(len) = read_u16(&mut response_stream) { len } else { return };
167 let mut buf = QueryBuf::new_zeroed(len);
168 if response_stream.len() < len as usize { return; }
169 buf.copy_from_slice(&response_stream[..len as usize]);
170 response_stream = &response_stream[len as usize..];
171 let _ = builder.process_response(&buf);
173 let _ = builder.finish_proof();
176 const MAX_REQUESTS: usize = 10;
177 /// A simple state machine which will generate a series of queries and process the responses until
178 /// it has built a DNSSEC proof.
180 /// A [`ProofBuilder`] driver starts with [`ProofBuilder::new`], fetching the state machine and
181 /// initial query. As long as [`ProofBuilder::awaiting_responses`] returns true, responses should
182 /// be read from the resolver. For each query response read from the DNS resolver,
183 /// [`ProofBuilder::process_response`] should be called, and each fresh query returned should be
184 /// sent to the resolver. Once [`ProofBuilder::awaiting_responses`] returns false,
185 /// [`ProofBuilder::finish_proof`] should be called to fetch the resulting proof.
187 /// To build a DNSSEC proof using a DoH server, take each [`QueryBuf`], encode it as base64url, and
188 /// make a query to `https://doh-server/endpoint?dns=base64url_encoded_query` with an `Accept`
189 /// header of `application/dns-message`. Each response, in raw binary, can be fed directly into
190 /// [`ProofBuilder::process_response`].
191 pub struct ProofBuilder {
194 dnskeys_requested: Vec<Name>,
195 pending_queries: usize,
200 /// Constructs a new [`ProofBuilder`] and an initial query to send to the recursive resolver to
201 /// begin the proof building process.
203 /// Given a correctly-functioning resolver the proof will ultimately be able to prove the
204 /// contents of any records with the given `ty`pe at the given `name` (as long as the given
205 /// `ty`pe is supported by this library).
207 /// You can find constants for supported standard types in the [`crate::rr`] module.
208 pub fn new(name: &Name, ty: u16) -> (ProofBuilder, QueryBuf) {
209 let initial_query = build_query(name, ty);
213 dnskeys_requested: Vec::with_capacity(MAX_REQUESTS),
219 /// Returns true as long as further responses are expected from the resolver.
221 /// As long as this returns true, responses should be read from the resolver and passed to
222 /// [`Self::process_response`]. Once this returns false, [`Self::finish_proof`] should be used
223 /// to (possibly) get the final proof.
224 pub fn awaiting_responses(&self) -> bool {
225 self.pending_queries > 0 && self.queries_made <= MAX_REQUESTS
228 /// Processes a query response from the recursive resolver, returning a list of new queries to
229 /// send to the resolver.
230 pub fn process_response(&mut self, resp: &QueryBuf) -> Result<Vec<QueryBuf>, ()> {
231 if self.pending_queries == 0 { return Err(()); }
233 let mut rrsig_key_names = Vec::new();
234 let min_ttl = handle_response(&resp, &mut self.proof, &mut rrsig_key_names)?;
235 self.min_ttl = cmp::min(self.min_ttl, min_ttl);
236 self.pending_queries -= 1;
238 rrsig_key_names.sort_unstable();
239 rrsig_key_names.dedup();
241 let mut new_queries = Vec::with_capacity(2);
242 for key_name in rrsig_key_names.drain(..) {
243 if !self.dnskeys_requested.contains(&key_name) {
244 new_queries.push(build_query(&key_name, DnsKey::TYPE));
245 self.pending_queries += 1;
246 self.queries_made += 1;
247 self.dnskeys_requested.push(key_name.clone());
249 if key_name.as_str() != "." {
250 new_queries.push(build_query(&key_name, DS::TYPE));
251 self.pending_queries += 1;
252 self.queries_made += 1;
256 if self.queries_made <= MAX_REQUESTS {
263 /// Finalizes the proof, if one is available, and returns it as well as the TTL that should be
264 /// used to cache the proof (i.e. the lowest TTL of all records which were used to build the
266 pub fn finish_proof(self) -> Result<(Vec<u8>, u32), ()> {
267 if self.pending_queries > 0 || self.queries_made > MAX_REQUESTS {
270 Ok((self.proof, self.min_ttl))
275 #[cfg(feature = "std")]
276 fn send_query(stream: &mut TcpStream, query: &[u8]) -> Result<(), Error> {
277 stream.write_all(&(query.len() as u16).to_be_bytes())?;
278 stream.write_all(&query)?;
282 #[cfg(feature = "tokio")]
283 async fn send_query_async(stream: &mut TokioTcpStream, query: &[u8]) -> Result<(), Error> {
284 stream.write_all(&(query.len() as u16).to_be_bytes()).await?;
285 stream.write_all(&query).await?;
289 #[cfg(feature = "std")]
290 fn read_response(stream: &mut TcpStream) -> Result<QueryBuf, Error> {
291 let mut len_bytes = [0; 2];
292 stream.read_exact(&mut len_bytes)?;
293 let mut buf = QueryBuf::new_zeroed(u16::from_be_bytes(len_bytes));
294 stream.read_exact(&mut buf)?;
298 #[cfg(feature = "tokio")]
299 async fn read_response_async(stream: &mut TokioTcpStream) -> Result<QueryBuf, Error> {
300 let mut len_bytes = [0; 2];
301 stream.read_exact(&mut len_bytes).await?;
302 let mut buf = QueryBuf::new_zeroed(u16::from_be_bytes(len_bytes));
303 stream.read_exact(&mut buf).await?;
307 #[cfg(feature = "std")]
308 macro_rules! build_proof_impl {
309 ($stream: ident, $send_query: ident, $read_response: ident, $domain: expr, $ty: expr $(, $async_ok: tt)?) => { {
310 // We require the initial query to have already gone out, and assume our resolver will
311 // return any CNAMEs all the way to the final record in the response. From there, we just
312 // have to take any RRSIGs in the response and walk them up to the root. We do so
313 // iteratively, sending DNSKEY and DS lookups after every response, deduplicating requests
314 // using `dnskeys_requested`.
315 let (mut builder, initial_query) = ProofBuilder::new($domain, $ty);
316 $send_query(&mut $stream, &initial_query)
317 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
318 while builder.awaiting_responses() {
319 let response = $read_response(&mut $stream)
320 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
321 let new_queries = builder.process_response(&response)
322 .map_err(|()| Error::new(ErrorKind::Other, "Bad response"))?;
323 for query in new_queries {
324 $send_query(&mut $stream, &query)
325 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
329 builder.finish_proof()
330 .map_err(|()| Error::new(ErrorKind::Other, "Too many requests required"))
334 #[cfg(feature = "std")]
335 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
336 let mut stream = TcpStream::connect(resolver)?;
337 build_proof_impl!(stream, send_query, read_response, domain, ty)
340 #[cfg(feature = "tokio")]
341 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
342 let mut stream = TokioTcpStream::connect(resolver).await?;
343 build_proof_impl!(stream, send_query_async, read_response_async, domain, ty, { Ok::<(), Error>(()) })
346 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
347 /// well as the TTL for the proof provided by the recursive resolver.
349 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
350 /// module to validate the records contained.
351 #[cfg(feature = "std")]
352 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
353 build_proof(resolver, domain, A::TYPE)
356 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
357 /// as well as the TTL for the proof provided by the recursive resolver.
359 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
360 /// module to validate the records contained.
361 #[cfg(feature = "std")]
362 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
363 build_proof(resolver, domain, AAAA::TYPE)
366 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
367 /// as well as the TTL for the proof provided by the recursive resolver.
369 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
370 /// module to validate the records contained.
371 #[cfg(feature = "std")]
372 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
373 build_proof(resolver, domain, Txt::TYPE)
376 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
377 /// as well as the TTL for the proof provided by the recursive resolver.
379 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
380 /// module to validate the records contained.
381 #[cfg(feature = "std")]
382 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
383 build_proof(resolver, domain, TLSA::TYPE)
387 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
388 /// well as the TTL for the proof provided by the recursive resolver.
390 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
391 /// module to validate the records contained.
392 #[cfg(feature = "tokio")]
393 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
394 build_proof_async(resolver, domain, A::TYPE).await
397 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
398 /// as well as the TTL for the proof provided by the recursive resolver.
400 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
401 /// module to validate the records contained.
402 #[cfg(feature = "tokio")]
403 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
404 build_proof_async(resolver, domain, AAAA::TYPE).await
407 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
408 /// as well as the TTL for the proof provided by the recursive resolver.
410 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
411 /// module to validate the records contained.
412 #[cfg(feature = "tokio")]
413 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
414 build_proof_async(resolver, domain, Txt::TYPE).await
417 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
418 /// as well as the TTL for the proof provided by the recursive resolver.
420 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
421 /// module to validate the records contained.
422 #[cfg(feature = "tokio")]
423 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
424 build_proof_async(resolver, domain, TLSA::TYPE).await
427 #[cfg(all(feature = "validation", feature = "std", test))]
430 use crate::validation::*;
432 use rand::seq::SliceRandom;
434 use std::net::ToSocketAddrs;
435 use std::time::SystemTime;
438 fn test_cloudflare_txt_query() {
439 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
440 let query_name = "cloudflare.com.".try_into().unwrap();
441 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
443 let mut rrs = parse_rr_stream(&proof).unwrap();
444 rrs.shuffle(&mut rand::rngs::OsRng);
445 let verified_rrs = verify_rr_stream(&rrs).unwrap();
446 assert!(verified_rrs.verified_rrs.len() > 1);
448 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
449 assert!(verified_rrs.valid_from < now);
450 assert!(verified_rrs.expires > now);
454 fn test_sha1_query() {
455 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
456 let query_name = "benthecarman.com.".try_into().unwrap();
457 let (proof, _) = build_a_proof(sockaddr, &query_name).unwrap();
459 let mut rrs = parse_rr_stream(&proof).unwrap();
460 rrs.shuffle(&mut rand::rngs::OsRng);
461 let verified_rrs = verify_rr_stream(&rrs).unwrap();
462 assert!(verified_rrs.verified_rrs.len() >= 1);
464 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
465 assert!(verified_rrs.valid_from < now);
466 assert!(verified_rrs.expires > now);
470 fn test_txt_query() {
471 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
472 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
473 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
475 let mut rrs = parse_rr_stream(&proof).unwrap();
476 rrs.shuffle(&mut rand::rngs::OsRng);
477 let verified_rrs = verify_rr_stream(&rrs).unwrap();
478 assert_eq!(verified_rrs.verified_rrs.len(), 1);
480 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
481 assert!(verified_rrs.valid_from < now);
482 assert!(verified_rrs.expires > now);
486 fn test_cname_query() {
487 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
488 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
489 let query_name = "cname_test.matcorallo.com.".try_into().unwrap();
490 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
492 let mut rrs = parse_rr_stream(&proof).unwrap();
493 rrs.shuffle(&mut rand::rngs::OsRng);
494 let verified_rrs = verify_rr_stream(&rrs).unwrap();
495 assert_eq!(verified_rrs.verified_rrs.len(), 2);
497 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
498 assert!(verified_rrs.valid_from < now);
499 assert!(verified_rrs.expires > now);
501 let resolved_rrs = verified_rrs.resolve_name(&query_name);
502 assert_eq!(resolved_rrs.len(), 1);
503 if let RR::Txt(txt) = &resolved_rrs[0] {
504 assert_eq!(txt.name.as_str(), "txt_test.matcorallo.com.");
505 assert_eq!(txt.data, b"dnssec_prover_test");
510 #[cfg(feature = "tokio")]
511 use tokio_crate as tokio;
513 #[cfg(feature = "tokio")]
515 async fn test_txt_query_async() {
516 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
517 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
518 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
520 let mut rrs = parse_rr_stream(&proof).unwrap();
521 rrs.shuffle(&mut rand::rngs::OsRng);
522 let verified_rrs = verify_rr_stream(&rrs).unwrap();
523 assert_eq!(verified_rrs.verified_rrs.len(), 1);
525 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
526 assert!(verified_rrs.valid_from < now);
527 assert!(verified_rrs.expires > now);
530 #[cfg(feature = "tokio")]
532 async fn test_cross_domain_cname_query_async() {
533 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
534 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
535 let query_name = "wildcard.x_domain_cname_wild.matcorallo.com.".try_into().unwrap();
536 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
538 let mut rrs = parse_rr_stream(&proof).unwrap();
539 rrs.shuffle(&mut rand::rngs::OsRng);
540 let verified_rrs = verify_rr_stream(&rrs).unwrap();
541 assert_eq!(verified_rrs.verified_rrs.len(), 2);
543 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
544 assert!(verified_rrs.valid_from < now);
545 assert!(verified_rrs.expires > now);
547 let resolved_rrs = verified_rrs.resolve_name(&query_name);
548 assert_eq!(resolved_rrs.len(), 1);
549 if let RR::Txt(txt) = &resolved_rrs[0] {
550 assert_eq!(txt.name.as_str(), "matt.user._bitcoin-payment.mattcorallo.com.");
551 assert!(txt.data.starts_with(b"bitcoin:"));
556 #[cfg(feature = "tokio")]
558 async fn test_dname_wildcard_query_async() {
559 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
560 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
561 let query_name = "wildcard_a.wildcard_b.dname_test.dnssec_proof_tests.bitcoin.ninja.".try_into().unwrap();
562 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
564 let mut rrs = parse_rr_stream(&proof).unwrap();
565 rrs.shuffle(&mut rand::rngs::OsRng);
566 let verified_rrs = verify_rr_stream(&rrs).unwrap();
567 assert_eq!(verified_rrs.verified_rrs.len(), 3);
569 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
570 assert!(verified_rrs.valid_from < now);
571 assert!(verified_rrs.expires > now);
573 let resolved_rrs = verified_rrs.resolve_name(&query_name);
574 assert_eq!(resolved_rrs.len(), 1);
575 if let RR::Txt(txt) = &resolved_rrs[0] {
576 assert_eq!(txt.name.as_str(), "cname.wildcard_test.dnssec_proof_tests.bitcoin.ninja.");
577 assert_eq!(txt.data, b"wildcard_test");