Inside Bitcoin

1#!/usr/bin/env python3
2# Copyright (c) 2014-present The Bitcoin Core developers
3# Distributed under the MIT software license, see the accompanying
4# file COPYING or http://www.opensource.org/licenses/mit-license.php.
5'''
6Script to generate list of seed nodes for kernel/chainparams.cpp.
7
8This script expects three text files in the directory that is passed as an
9argument:
10
11    nodes_main.txt
12    nodes_signet.txt
13    nodes_test.txt
14    nodes_testnet4.txt
15
16These files must consist of lines in the format
17
18    <ip>:<port>
19    [<ipv6>]:<port>
20    <onion>.onion:<port>
21    <i2p>.b32.i2p:<port>
22
23The output will be several data structures with the peers in binary format:
24
25   inline constexpr uint8_t chainparams_seed_{main,signet,test,testnet4}[]{
26       ...
27   };
28
29These should be pasted into `src/chainparamsseeds.h`.
30'''
31
32from base64 import b32decode
33from enum import Enum
34import sys
35import os
36import re
37
38class BIP155Network(Enum):
39    IPV4 = 1
40    IPV6 = 2
41    TORV2 = 3  # no longer supported
42    TORV3 = 4
43    I2P = 5
44    CJDNS = 6
45
46def name_to_bip155(addr):
47    '''Convert address string to BIP155 (networkID, addr) tuple.'''
48    if addr.endswith('.onion'):
49        vchAddr = b32decode(addr[0:-6], True)
50        if len(vchAddr) == 35:
51            assert vchAddr[34] == 3
52            return (BIP155Network.TORV3, vchAddr[:32])
53        elif len(vchAddr) == 10:
54            return (BIP155Network.TORV2, vchAddr)
55        else:
56            raise ValueError('Invalid onion %s' % vchAddr)
57    elif addr.endswith('.b32.i2p'):
58        vchAddr = b32decode(addr[0:-8] + '====', True)
59        if len(vchAddr) == 32:
60            return (BIP155Network.I2P, vchAddr)
61        else:
62            raise ValueError(f'Invalid I2P {vchAddr}')
63    elif '.' in addr: # IPv4
64        return (BIP155Network.IPV4, bytes((int(x) for x in addr.split('.'))))
65    elif ':' in addr: # IPv6 or CJDNS
66        sub = [[], []] # prefix, suffix
67        x = 0
68        addr = addr.split(':')
69        for i,comp in enumerate(addr):
70            if comp == '':
71                if i == 0 or i == (len(addr)-1): # skip empty component at beginning or end
72                    continue
73                x += 1 # :: skips to suffix
74                assert x < 2
75            else: # two bytes per component
76                val = int(comp, 16)
77                sub[x].append(val >> 8)
78                sub[x].append(val & 0xff)
79        nullbytes = 16 - len(sub[0]) - len(sub[1])
80        assert (x == 0 and nullbytes == 0) or (x == 1 and nullbytes > 0)
81        addr_bytes = bytes(sub[0] + ([0] * nullbytes) + sub[1])
82        if addr_bytes[0] == 0xfc:
83            # Assume that seeds with fc00::/8 addresses belong to CJDNS,
84            # not to the publicly unroutable "Unique Local Unicast" network, see
85            # RFC4193: https://datatracker.ietf.org/doc/html/rfc4193#section-8
86            return (BIP155Network.CJDNS, addr_bytes)
87        else:
88            return (BIP155Network.IPV6, addr_bytes)
89    else:
90        raise ValueError('Could not parse address %s' % addr)
91
92def parse_spec(s):
93    '''Convert endpoint string to BIP155 (networkID, addr, port) tuple.'''
94    match = re.match(r'\[([0-9a-fA-F:]+)\](?::([0-9]+))?$', s)
95    if match: # ipv6
96        host = match.group(1)
97        port = match.group(2)
98    elif s.count(':') > 1: # ipv6, no port
99        host = s
100        port = ''
101    else:
102        (host,_,port) = s.partition(':')
103
104    if not port:
105        port = 0
106    else:
107        port = int(port)
108
109    host = name_to_bip155(host)
110
111    if host[0] == BIP155Network.TORV2:
112        return None  # TORV2 is no longer supported, so we ignore it
113    else:
114        return host + (port, )
115
116def ser_compact_size(l):
117    r = b""
118    if l < 253:
119        r = l.to_bytes(1, "little")
120    elif l < 0x10000:
121        r = (253).to_bytes(1, "little") + l.to_bytes(2, "little")
122    elif l < 0x100000000:
123        r = (254).to_bytes(1, "little") + l.to_bytes(4, "little")
124    else:
125        r = (255).to_bytes(1, "little") + l.to_bytes(8, "little")
126    return r
127
128def bip155_serialize(spec):
129    '''
130    Serialize (networkID, addr, port) tuple to BIP155 binary format.
131    '''
132    r = b""
133    r += spec[0].value.to_bytes(1, "little")
134    r += ser_compact_size(len(spec[1]))
135    r += spec[1]
136    r += spec[2].to_bytes(2, "big")
137    return r
138
139def process_nodes(g, f, structname):
140    g.write("inline constexpr uint8_t %s[]{\n" % structname)
141    for line in f:
142        comment = line.find('#')
143        if comment != -1:
144            line = line[0:comment]
145        line = line.strip()
146        if not line:
147            continue
148
149        spec = parse_spec(line)
150        if spec is None:  # ignore this entry (e.g. no longer supported addresses like TORV2)
151            continue
152        blob = bip155_serialize(spec)
153        hoststr = ','.join(('0x%02x' % b) for b in blob)
154        g.write(f'    {hoststr},\n')
155    g.write('};\n')
156
157def main():
158    if len(sys.argv)<2:
159        print(('Usage: %s <path_to_nodes_txt>' % sys.argv[0]), file=sys.stderr)
160        sys.exit(1)
161    g = sys.stdout
162    indir = sys.argv[1]
163    g.write('// Copyright (c) The Bitcoin Core developers\n')
164    g.write('// Distributed under the MIT software license, see the accompanying\n')
165    g.write('// file COPYING or https://opensource.org/license/mit.\n\n')
166    g.write('#ifndef BITCOIN_CHAINPARAMSSEEDS_H\n')
167    g.write('#define BITCOIN_CHAINPARAMSSEEDS_H\n')
168    g.write('/**\n')
169    g.write(' * List of fixed seed nodes for the bitcoin network\n')
170    g.write(' * AUTOGENERATED by contrib/seeds/generate-seeds.py\n')
171    g.write(' *\n')
172    g.write(' * Each line contains a BIP155 serialized (networkID, addr, port) tuple.\n')
173    g.write(' */\n')
174    with open(os.path.join(indir,'nodes_main.txt'), 'r') as f:
175        process_nodes(g, f, 'chainparams_seed_main')
176    g.write('\n')
177    with open(os.path.join(indir,'nodes_signet.txt'), 'r') as f:
178        process_nodes(g, f, 'chainparams_seed_signet')
179    g.write('\n')
180    with open(os.path.join(indir,'nodes_test.txt'), 'r') as f:
181        process_nodes(g, f, 'chainparams_seed_test')
182    g.write('\n')
183    with open(os.path.join(indir,'nodes_testnet4.txt'), 'r') as f:
184        process_nodes(g, f, 'chainparams_seed_testnet4')
185    g.write('#endif // BITCOIN_CHAINPARAMSSEEDS_H\n')
186
187if __name__ == '__main__':
188    main()
189