virtu / darkseed

A PoC python DNS seeder for Bitcoin supporting all network types

darkseed

A proof-of-concept darknet Bitcoin DNS seeder.

Components

darkseed (server)

darkseed can advertise Onion, I2P and CJDNS node addresses using custom-encoded DNS AAAA records which use a BIP155-like format (essentially BIP155 sans timestamp and port). Although CJDNS addresses could be represented using regular AAAA records, for the time being they use the BIP155-like encoding to make them easily distinguishable from regular IPv6 addresses.

darkseed can serve this data over the IP, Onion, I2P and Cjdns networks. To provide reachability via Onion and I2P, the seeder supports DNS via TCP; Cjdns is handled via regular DNS via UDP. Consequently, darkseed can help bootstrap darknet Bitcoin nodes by providing them with darknet peers without exiting the darknet.

darkdig (client)

Tool to send DNS queries and decode darkseed's custom-encoded DNS AAAA records.

darkseed will answer the A, AAAA, and ANY queries sent to the base domain with IPv4, IPv6, and a mix of IPv4/IPv6 addresses, respectively.

Particular addresses types can be queried via subdomains, which use a similar format as the x subdomain used to query for particular service bits. The subdomain starts with n (for network id) and is followed by the network ids defined in BIP155. The following subdomains are supported:

• n1 for IPv4 addresses
• n2 for IPv6 addresses
• n4 for TorV3 addresses
• n5 for I2P addresses
• n6 for CJDNS addresses

Yggdrasil (0x07) and deprecated TorV2 (0x03) are not supported.

Example

darkdig --type AAAA n4.dnsseed.21.ninja

; <<>> darkdig 0.13 <<>> @192.168.178.1 -p 53 -l INFO n4.dnsseed.21.ninja
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13738
;; flags: qr rd ra, QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;;QUESTION SECTION:
; domain=n4.dnsseed.21.ninja., rdclass=IN, rdtype=AAAA

;;ANSWER SECTION:
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc0e:3854:4700::
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc0c:a113:277b:8ff9:1907:8e03:b934:c4b9
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc00:604:1070:cbfe:535b:2114:e03f:bfe0
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc0b:bf41:594e:81af:422f:548a:ca77:4ff
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc09:27b:4555:da65:1004:87b2:db4d:a55b
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc08:5fcf:75f8:61e6:88f3:42e7:eb5f:4116
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc05:4481:9e78:3fda:b3ef:ec3e:6a99:4e14
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc03:1b2c:aad4:a5b4:95be:63c6:3dc8:eea3
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc06:322b:33eb:305a:e1da:6cc9:6dfa:4b1d
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc07:1d56:471:e890:3b08:b458:c0e0:d33a
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc02:897a:964:1be6:426:1d94:5830:a481
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc01:6dd3:3743:bcd3:b255:a44d:2f41:4088
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc04:da30:9f01:1e18:1a9f:da06:a104:c159
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc0a:fb6e:3c6d:8ef6:c438:a6e6:f96a:68e
domain=n4.dnsseed.21.ninja., ttl=60, rdclass=IN, rdtype=AAAA, data=fc0d:1639:6d34:1026:ae6:73b:7dbd:80cb
;; ->>custom AAAA encoding<<-
;; ->>custom AAAA-encoded address <<- record: 0, net_type: onion_v3, address: cbymx7stlmqrjyb7x7qg3uzxio6nhmsvurgs6qkarcexucledptbtiad.onion
;; ->>custom AAAA-encoded address <<- record: 1, net_type: onion_v3, address: eyoziwbqusarwlfk2ss3jfn6mpdd3shoupndbhybdymbvh62a2qzjnid.onion
;; ->>custom AAAA-encoded address <<- record: 2, net_type: onion_v3, address: yfmujam6pa75vm7p5q7gvgkocqzcwm7lgbnodwtmzfw7usy5dvlgqyqd.onion
;; ->>custom AAAA-encoded address <<- record: 3, net_type: onion_v3, address: ohujaoyiwrmmbygthjp465pymhtir42c47vv6qiwaj5ukvo2muikqnad.onion
;; ->>custom AAAA-encoded address <<- record: 4, net_type: onion_v3, address: q6znwtnflp5w4pdnr33miofg434wubuox5avstubv5bc6vekzj3zssqd.onion
;; ->>custom AAAA-encoded address <<- record: 5, net_type: onion_v3, address: 76qrgj33r74rsb4oao4tjrfzcy4w2naqeyfombz3pw6ybszykrdrfyad.onion

;; Query time: 100 msec
;; SERVER: 192.168.178.1#53
;; WHEN: Tue Oct 08 14:10:05 CEST 2024
;; MSG SIZE  rcvd: 457

NOTE: The repository contains a Nix flake so to test without installing use nix shell . -c darkdig dnsseed.21.ninja

You can also use regular dig to query the server, although this means the NULL record won't be decoded:

dig AAAA n4.dnsseed.21.ninja

; <<>> DiG 9.10.6 <<>> AAAA n4.dnsseed.21.ninja
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57127
;; flags: qr rd ra; QUERY: 1, ANSWER: 15, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;n4.dnsseed.21.ninja.           IN      AAAA

;; ANSWER SECTION:
n4.dnsseed.21.ninja.    60      IN      AAAA    fc04:472e:e536:8b03:437b:f23c:2804:ee50
n4.dnsseed.21.ninja.    60      IN      AAAA    fc0b:ae5f:8747:4486:1c84:c924:b438:4e7
n4.dnsseed.21.ninja.    60      IN      AAAA    fc08:b50:7b9f:47b6:20fb:8fe2:e4ed:e733
n4.dnsseed.21.ninja.    60      IN      AAAA    fc0d:5496:409a:68ee:5623:5ca8:7559:c69
n4.dnsseed.21.ninja.    60      IN      AAAA    fc07:e17a:4ff:d8bb:3343:7889:d51:d64b
n4.dnsseed.21.ninja.    60      IN      AAAA    fc0a:7d1:2576:88ca:4b1b:b8c6:1226:8194
n4.dnsseed.21.ninja.    60      IN      AAAA    fc09:1bde:a8b1:7be1:d604:b177:3070:6d1
n4.dnsseed.21.ninja.    60      IN      AAAA    fc06:e6af:d1b5:37ed:a7fb:20ad:dce6:21a4
n4.dnsseed.21.ninja.    60      IN      AAAA    fc05:471b:b962:4636:c9ee:76b3:d5b9:7f9
n4.dnsseed.21.ninja.    60      IN      AAAA    fc0c:1895:3126:8e3c:bc46:f8a9:e18:e5fb
n4.dnsseed.21.ninja.    60      IN      AAAA    fc01:5881:ff18:a1fe:f697:1800:517e:f4a6
n4.dnsseed.21.ninja.    60      IN      AAAA    fc03:bc43:9214:5870:3b37:f045:3f8e:2df7
n4.dnsseed.21.ninja.    60      IN      AAAA    fc00:604:4b0a:6f82:d4a5:b37f:4a49:6969
n4.dnsseed.21.ninja.    60      IN      AAAA    fc02:d61b:35e7:ac78:422:5973:5cf9:bf4a
n4.dnsseed.21.ninja.    60      IN      AAAA    fc0e:f3b8:5200::

;; Query time: 65 msec
;; SERVER: 192.168.178.1#53(192.168.178.1)
;; WHEN: Tue Oct 08 15:05:35 CEST 2024
;; MSG SIZE  rcvd: 468

Local Testing (with Nix)

Make sure to make reachable node data (generated with p2p-crawler) available in a node_data directory under the git repository root.

# Start a darkseed instance serving nodes via DNS on port 8053
nix run . -- --log-level debug --crawler-path $(git rev-parse --show-toplevel)/test_data --port 8053 --zone seed.acme.com

# Test
nix shell . -c darkdig seed.acme.com --nameserver 127.0.0.1 -p 8053