_ Git - dnssec-prover/blob - src/query.rs

   1 //! This module exposes utilities for building DNSSEC proofs by directly querying a recursive
   2 //! resolver.
   3
   4 use core::{cmp, ops};
   5 use alloc::vec;
   6 use alloc::vec::Vec;
   7
   8 #[cfg(feature = "std")]
   9 use std::net::{SocketAddr, TcpStream};
  10 #[cfg(feature = "std")]
  11 use std::io::{Read, Write, Error, ErrorKind};
  12
  13 #[cfg(feature = "tokio")]
  14 use tokio_crate::net::TcpStream as TokioTcpStream;
  15 #[cfg(feature = "tokio")]
  16 use tokio_crate::io::{AsyncReadExt, AsyncWriteExt};
  17
  18 use crate::rr::*;
  19 use crate::ser::*;
  20
  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(test)]
  25 const STACK_BUF_LIMIT: u16 = 32;
  26 #[cfg(not(test))]
  27 const STACK_BUF_LIMIT: u16 = 2048;
  28
  29 /// A buffer for storing queries and responses.
  30 #[derive(Clone, PartialEq, Eq)]
  31 pub struct QueryBuf {
  32         buf: [u8; STACK_BUF_LIMIT as usize],
  33         heap_buf: Vec<u8>,
  34         len: u16,
  35 }
  36 impl QueryBuf {
  37         fn new_zeroed(len: u16) -> Self {
  38                 let heap_buf = if len > STACK_BUF_LIMIT { vec![0; len as usize] } else { Vec::new() };
  39                 Self {
  40                         buf: [0; STACK_BUF_LIMIT as usize],
  41                         heap_buf,
  42                         len
  43                 }
  44         }
  45         pub(crate) fn extend_from_slice(&mut self, sl: &[u8]) {
  46                 let new_len = self.len.saturating_add(sl.len() as u16);
  47                 let was_heap = self.len > STACK_BUF_LIMIT;
  48                 let is_heap = new_len > STACK_BUF_LIMIT;
  49                 if was_heap != is_heap {
  50                         self.heap_buf = vec![0; new_len as usize];
  51                         self.heap_buf[..self.len as usize].copy_from_slice(&self.buf[..self.len as usize]);
  52                 }
  53                 let target = if is_heap {
  54                         self.heap_buf.resize(new_len as usize, 0);
  55                         &mut self.heap_buf[self.len as usize..]
  56                 } else {
  57                         &mut self.buf[self.len as usize..new_len as usize]
  58                 };
  59                 target.copy_from_slice(sl);
  60                 self.len = new_len;
  61         }
  62 }
  63 impl ops::Deref for QueryBuf {
  64         type Target = [u8];
  65         fn deref(&self) -> &[u8] {
  66                 if self.len > STACK_BUF_LIMIT {
  67                         &self.heap_buf
  68                 } else {
  69                         &self.buf[..self.len as usize]
  70                 }
  71         }
  72 }
  73 impl ops::DerefMut for QueryBuf {
  74         fn deref_mut(&mut self) -> &mut [u8] {
  75                 if self.len > STACK_BUF_LIMIT {
  76                         &mut self.heap_buf
  77                 } else {
  78                         &mut self.buf[..self.len as usize]
  79                 }
  80         }
  81 }
  82
  83 // We don't care about transaction IDs as we're only going to accept signed data. Thus, we use
  84 // this constant instead of a random value.
  85 const TXID: u16 = 0x4242;
  86
  87 fn build_query(domain: &Name, ty: u16) -> QueryBuf {
  88         let mut query = QueryBuf::new_zeroed(0);
  89         let query_msg_len: u16 = 2 + 2 + 8 + 2 + 2 + name_len(domain) + 11;
  90         query.extend_from_slice(&query_msg_len.to_be_bytes());
  91         query.extend_from_slice(&TXID.to_be_bytes());
  92         query.extend_from_slice(&[0x01, 0x20]); // Flags: Recursive, Authenticated Data
  93         query.extend_from_slice(&[0, 1, 0, 0, 0, 0, 0, 1]); // One question, One additional
  94         write_name(&mut query, domain);
  95         query.extend_from_slice(&ty.to_be_bytes());
  96         query.extend_from_slice(&1u16.to_be_bytes()); // INternet class
  97         query.extend_from_slice(&[0, 0, 0x29]); // . OPT
  98         query.extend_from_slice(&0u16.to_be_bytes()); // 0 UDP payload size
  99         query.extend_from_slice(&[0, 0]); // EDNS version 0
 100         query.extend_from_slice(&0x8000u16.to_be_bytes()); // Accept DNSSEC RRs
 101         query.extend_from_slice(&0u16.to_be_bytes()); // No additional data
 102         query
 103 }
 104
 105 #[cfg(fuzzing)]
 106 /// Read some input and parse it as if it came from a server, for fuzzing.
 107 pub fn fuzz_response(response: &[u8]) {
 108         let (mut proof, mut names) = (Vec::new(), Vec::new());
 109         let _ = handle_response(response, &mut proof, &mut names);
 110 }
 111
 112 fn handle_response(resp: &[u8], proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, ()> {
 113         let mut read: &[u8] = resp;
 114         if read_u16(&mut read)? != TXID { return Err(()); }
 115         // 2 byte transaction ID
 116         let flags = read_u16(&mut read)?;
 117         if flags & 0b1000_0000_0000_0000 == 0 {
 118                 return Err(());
 119         }
 120         if flags & 0b0111_1010_0000_0111 != 0 {
 121                 return Err(());
 122         }
 123         if flags & 0b10_0000 == 0 {
 124                 return Err(());
 125         }
 126         let questions = read_u16(&mut read)?;
 127         if questions != 1 { return Err(()); }
 128         let answers = read_u16(&mut read)?;
 129         if answers == 0 { return Err(()); }
 130         let _authorities = read_u16(&mut read)?;
 131         let _additional = read_u16(&mut read)?;
 132
 133         for _ in 0..questions {
 134                 read_wire_packet_name(&mut read, resp)?;
 135                 read_u16(&mut read)?; // type
 136                 read_u16(&mut read)?; // class
 137         }
 138
 139         // Only read the answers (skip authorities and additional) as that's all we care about.
 140         let mut min_ttl = u32::MAX;
 141         for _ in 0..answers {
 142                 let (rr, ttl) = parse_wire_packet_rr(&mut read, &resp)?;
 143                 write_rr(&rr, ttl, proof);
 144                 min_ttl = cmp::min(min_ttl, ttl);
 145                 if let RR::RRSig(rrsig) = rr { rrsig_key_names.push(rrsig.key_name); }
 146         }
 147         Ok(min_ttl)
 148 }
 149
 150 const MAX_REQUESTS: usize = 10;
 151 /// A simple state machine which will generate a series of queries and process the responses until
 152 /// it has built a DNSSEC proof.
 153 ///
 154 /// A [`ProofBuilder`] driver starts with [`ProofBuilder::new`], fetching the state machine and
 155 /// initial query. As long as [`ProofBuilder::awaiting_responses`] returns true, responses should
 156 /// be read from the resolver. For each query response read from the DNS resolver,
 157 /// [`ProofBuilder::process_response`] should be called, and each fresh query returned should be
 158 /// sent to the resolver. Once [`ProofBuilder::awaiting_responses`] returns false,
 159 /// [`ProofBuilder::finish_proof`] should be called to fetch the resulting proof.
 160 pub struct ProofBuilder {
 161         proof: Vec<u8>,
 162         min_ttl: u32,
 163         dnskeys_requested: Vec<Name>,
 164         pending_queries: usize,
 165         queries_made: usize,
 166 }
 167
 168 impl ProofBuilder {
 169         /// Constructs a new [`ProofBuilder`] and an initial query to send to the recursive resolver to
 170         /// begin the proof building process.
 171         ///
 172         /// Given a correctly-functioning resolver the proof will ultimately be able to prove the
 173         /// contents of any records with the given `ty`pe at the given `name` (as long as the given
 174         /// `ty`pe is supported by this library).
 175         ///
 176         /// You can find constants for supported standard types in the [`crate::rr`] module.
 177         pub fn new(name: &Name, ty: u16) -> (ProofBuilder, QueryBuf) {
 178                 let initial_query = build_query(name, ty);
 179                 (ProofBuilder {
 180                         proof: Vec::new(),
 181                         min_ttl: u32::MAX,
 182                         dnskeys_requested: Vec::with_capacity(MAX_REQUESTS),
 183                         pending_queries: 1,
 184                         queries_made: 1,
 185                 }, initial_query)
 186         }
 187
 188         /// Returns true as long as further responses are expected from the resolver.
 189         ///
 190         /// As long as this returns true, responses should be read from the resolver and passed to
 191         /// [`Self::process_response`]. Once this returns false, [`Self::finish_proof`] should be used
 192         /// to (possibly) get the final proof.
 193         pub fn awaiting_responses(&self) -> bool {
 194                 self.pending_queries > 0 && self.queries_made <= MAX_REQUESTS
 195         }
 196
 197         /// Processes a query response from the recursive resolver, returning a list of new queries to
 198         /// send to the resolver.
 199         pub fn process_response(&mut self, resp: &QueryBuf) -> Result<Vec<QueryBuf>, ()> {
 200                 if self.pending_queries == 0 { return Err(()); }
 201
 202                 let mut rrsig_key_names = Vec::new();
 203                 let min_ttl = handle_response(&resp, &mut self.proof, &mut rrsig_key_names)?;
 204                 self.min_ttl = cmp::min(self.min_ttl, min_ttl);
 205                 self.pending_queries -= 1;
 206
 207                 rrsig_key_names.sort_unstable();
 208                 rrsig_key_names.dedup();
 209
 210                 let mut new_queries = Vec::with_capacity(2);
 211                 for key_name in rrsig_key_names.drain(..) {
 212                         if !self.dnskeys_requested.contains(&key_name) {
 213                                 new_queries.push(build_query(&key_name, DnsKey::TYPE));
 214                                 self.pending_queries += 1;
 215                                 self.queries_made += 1;
 216                                 self.dnskeys_requested.push(key_name.clone());
 217
 218                                 if key_name.as_str() != "." {
 219                                         new_queries.push(build_query(&key_name, DS::TYPE));
 220                                         self.pending_queries += 1;
 221                                         self.queries_made += 1;
 222                                 }
 223                         }
 224                 }
 225                 if self.queries_made <= MAX_REQUESTS {
 226                         Ok(new_queries)
 227                 } else {
 228                         Ok(Vec::new())
 229                 }
 230         }
 231
 232         /// Finalizes the proof, if one is available, and returns it as well as the TTL that should be
 233         /// used to cache the proof (i.e. the lowest TTL of all records which were used to build the
 234         /// proof).
 235         pub fn finish_proof(self) -> Result<(Vec<u8>, u32), ()> {
 236                 if self.pending_queries > 0 || self.queries_made > MAX_REQUESTS {
 237                         Err(())
 238                 } else {
 239                         Ok((self.proof, self.min_ttl))
 240                 }
 241         }
 242 }
 243
 244 #[cfg(feature = "std")]
 245 fn send_query(stream: &mut TcpStream, query: &[u8]) -> Result<(), Error> {
 246         stream.write_all(&query)?;
 247         Ok(())
 248 }
 249
 250 #[cfg(feature = "tokio")]
 251 async fn send_query_async(stream: &mut TokioTcpStream, query: &[u8]) -> Result<(), Error> {
 252         stream.write_all(&query).await?;
 253         Ok(())
 254 }
 255
 256 #[cfg(feature = "std")]
 257 fn read_response(stream: &mut TcpStream) -> Result<QueryBuf, Error> {
 258         let mut len_bytes = [0; 2];
 259         stream.read_exact(&mut len_bytes)?;
 260         let mut buf = QueryBuf::new_zeroed(u16::from_be_bytes(len_bytes));
 261         stream.read_exact(&mut buf)?;
 262         Ok(buf)
 263 }
 264
 265 #[cfg(feature = "tokio")]
 266 async fn read_response_async(stream: &mut TokioTcpStream) -> Result<QueryBuf, Error> {
 267         let mut len_bytes = [0; 2];
 268         stream.read_exact(&mut len_bytes).await?;
 269         let mut buf = QueryBuf::new_zeroed(u16::from_be_bytes(len_bytes));
 270         stream.read_exact(&mut buf).await?;
 271         Ok(buf)
 272 }
 273
 274 #[cfg(feature = "std")]
 275 macro_rules! build_proof_impl {
 276         ($stream: ident, $send_query: ident, $read_response: ident, $domain: expr, $ty: expr $(, $async_ok: tt)?) => { {
 277                 // We require the initial query to have already gone out, and assume our resolver will
 278                 // return any CNAMEs all the way to the final record in the response. From there, we just
 279                 // have to take any RRSIGs in the response and walk them up to the root. We do so
 280                 // iteratively, sending DNSKEY and DS lookups after every response, deduplicating requests
 281                 // using `dnskeys_requested`.
 282                 let (mut builder, initial_query) = ProofBuilder::new($domain, $ty);
 283                 $send_query(&mut $stream, &initial_query)
 284                         $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 285                 while builder.awaiting_responses() {
 286                         let response = $read_response(&mut $stream)
 287                                 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 288                         let new_queries = builder.process_response(&response)
 289                                 .map_err(|()| Error::new(ErrorKind::Other, "Bad response"))?;
 290                         for query in new_queries {
 291                                 $send_query(&mut $stream, &query)
 292                                         $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 293                         }
 294                 }
 295
 296                 builder.finish_proof()
 297                         .map_err(|()| Error::new(ErrorKind::Other, "Too many requests required"))
 298         } }
 299 }
 300
 301 #[cfg(feature = "std")]
 302 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
 303         let mut stream = TcpStream::connect(resolver)?;
 304         build_proof_impl!(stream, send_query, read_response, domain, ty)
 305 }
 306
 307 #[cfg(feature = "tokio")]
 308 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
 309         let mut stream = TokioTcpStream::connect(resolver).await?;
 310         build_proof_impl!(stream, send_query_async, read_response_async, domain, ty, { Ok::<(), Error>(()) })
 311 }
 312
 313 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
 314 /// well as the TTL for the proof provided by the recursive resolver.
 315 ///
 316 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 317 /// module to validate the records contained.
 318 #[cfg(feature = "std")]
 319 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 320         build_proof(resolver, domain, A::TYPE)
 321 }
 322
 323 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
 324 /// as well as the TTL for the proof provided by the recursive resolver.
 325 ///
 326 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 327 /// module to validate the records contained.
 328 #[cfg(feature = "std")]
 329 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 330         build_proof(resolver, domain, AAAA::TYPE)
 331 }
 332
 333 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
 334 /// as well as the TTL for the proof provided by the recursive resolver.
 335 ///
 336 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 337 /// module to validate the records contained.
 338 #[cfg(feature = "std")]
 339 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 340         build_proof(resolver, domain, Txt::TYPE)
 341 }
 342
 343 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
 344 /// as well as the TTL for the proof provided by the recursive resolver.
 345 ///
 346 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 347 /// module to validate the records contained.
 348 #[cfg(feature = "std")]
 349 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 350         build_proof(resolver, domain, TLSA::TYPE)
 351 }
 352
 353
 354 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
 355 /// well as the TTL for the proof provided by the recursive resolver.
 356 ///
 357 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 358 /// module to validate the records contained.
 359 #[cfg(feature = "tokio")]
 360 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 361         build_proof_async(resolver, domain, A::TYPE).await
 362 }
 363
 364 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
 365 /// as well as the TTL for the proof provided by the recursive resolver.
 366 ///
 367 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 368 /// module to validate the records contained.
 369 #[cfg(feature = "tokio")]
 370 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 371         build_proof_async(resolver, domain, AAAA::TYPE).await
 372 }
 373
 374 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
 375 /// as well as the TTL for the proof provided by the recursive resolver.
 376 ///
 377 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 378 /// module to validate the records contained.
 379 #[cfg(feature = "tokio")]
 380 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 381         build_proof_async(resolver, domain, Txt::TYPE).await
 382 }
 383
 384 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
 385 /// as well as the TTL for the proof provided by the recursive resolver.
 386 ///
 387 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
 388 /// module to validate the records contained.
 389 #[cfg(feature = "tokio")]
 390 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 391         build_proof_async(resolver, domain, TLSA::TYPE).await
 392 }
 393
 394 #[cfg(all(feature = "validation", feature = "std", test))]
 395 mod tests {
 396         use super::*;
 397         use crate::validation::*;
 398
 399         use rand::seq::SliceRandom;
 400
 401         use std::net::ToSocketAddrs;
 402         use std::time::SystemTime;
 403
 404         #[test]
 405         fn test_cloudflare_txt_query() {
 406                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 407                 let query_name = "cloudflare.com.".try_into().unwrap();
 408                 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
 409
 410                 let mut rrs = parse_rr_stream(&proof).unwrap();
 411                 rrs.shuffle(&mut rand::rngs::OsRng);
 412                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 413                 assert!(verified_rrs.verified_rrs.len() > 1);
 414
 415                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 416                 assert!(verified_rrs.valid_from < now);
 417                 assert!(verified_rrs.expires > now);
 418         }
 419
 420         #[test]
 421         fn test_sha1_query() {
 422                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 423                 let query_name = "benthecarman.com.".try_into().unwrap();
 424                 let (proof, _) = build_a_proof(sockaddr, &query_name).unwrap();
 425
 426                 let mut rrs = parse_rr_stream(&proof).unwrap();
 427                 rrs.shuffle(&mut rand::rngs::OsRng);
 428                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 429                 assert!(verified_rrs.verified_rrs.len() >= 1);
 430
 431                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 432                 assert!(verified_rrs.valid_from < now);
 433                 assert!(verified_rrs.expires > now);
 434         }
 435
 436         #[test]
 437         fn test_txt_query() {
 438                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 439                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
 440                 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
 441
 442                 let mut rrs = parse_rr_stream(&proof).unwrap();
 443                 rrs.shuffle(&mut rand::rngs::OsRng);
 444                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 445                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
 446
 447                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 448                 assert!(verified_rrs.valid_from < now);
 449                 assert!(verified_rrs.expires > now);
 450         }
 451
 452         #[test]
 453         fn test_cname_query() {
 454                 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
 455                         let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
 456                         let query_name = "cname_test.matcorallo.com.".try_into().unwrap();
 457                         let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
 458
 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_eq!(verified_rrs.verified_rrs.len(), 2);
 463
 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);
 467
 468                         let resolved_rrs = verified_rrs.resolve_name(&query_name);
 469                         assert_eq!(resolved_rrs.len(), 1);
 470                         if let RR::Txt(txt) = &resolved_rrs[0] {
 471                                 assert_eq!(txt.name.as_str(), "txt_test.matcorallo.com.");
 472                                 assert_eq!(txt.data, b"dnssec_prover_test");
 473                         } else { panic!(); }
 474                 }
 475         }
 476
 477         #[cfg(feature = "tokio")]
 478         use tokio_crate as tokio;
 479
 480         #[cfg(feature = "tokio")]
 481         #[tokio::test]
 482         async fn test_txt_query_async() {
 483                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 484                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
 485                 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
 486
 487                 let mut rrs = parse_rr_stream(&proof).unwrap();
 488                 rrs.shuffle(&mut rand::rngs::OsRng);
 489                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 490                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
 491
 492                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 493                 assert!(verified_rrs.valid_from < now);
 494                 assert!(verified_rrs.expires > now);
 495         }
 496
 497         #[cfg(feature = "tokio")]
 498         #[tokio::test]
 499         async fn test_cross_domain_cname_query_async() {
 500                 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
 501                         let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
 502                         let query_name = "wildcard.x_domain_cname_wild.matcorallo.com.".try_into().unwrap();
 503                         let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
 504
 505                         let mut rrs = parse_rr_stream(&proof).unwrap();
 506                         rrs.shuffle(&mut rand::rngs::OsRng);
 507                         let verified_rrs = verify_rr_stream(&rrs).unwrap();
 508                         assert_eq!(verified_rrs.verified_rrs.len(), 2);
 509
 510                         let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 511                         assert!(verified_rrs.valid_from < now);
 512                         assert!(verified_rrs.expires > now);
 513
 514                         let resolved_rrs = verified_rrs.resolve_name(&query_name);
 515                         assert_eq!(resolved_rrs.len(), 1);
 516                         if let RR::Txt(txt) = &resolved_rrs[0] {
 517                                 assert_eq!(txt.name.as_str(), "matt.user._bitcoin-payment.mattcorallo.com.");
 518                                 assert!(txt.data.starts_with(b"bitcoin:"));
 519                         } else { panic!(); }
 520                 }
 521         }
 522 }