1 // Copyright (c) 2021-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 5 #include <netgroup.h>
6 7 #include <hash.h>
8 #include <uint256.h>
9 #include <util/asmap.h>
10 #include <util/log.h>
11 12 #include <cstddef>
13 14 uint256 NetGroupManager::GetAsmapVersion() const
15 {
16 return AsmapVersion(m_asmap);
17 }
18 19 std::vector<unsigned char> NetGroupManager::GetGroup(const CNetAddr& address) const
20 {
21 std::vector<unsigned char> vchRet;
22 // If non-empty asmap is supplied and the address is IPv4/IPv6,
23 // return ASN to be used for bucketing.
24 uint32_t asn = GetMappedAS(address);
25 if (asn != 0) { // Either asmap was empty, or address has non-asmappable net class (e.g. TOR).
26 vchRet.push_back(NET_IPV6); // IPv4 and IPv6 with same ASN should be in the same bucket
27 for (int i = 0; i < 4; i++) {
28 vchRet.push_back((asn >> (8 * i)) & 0xFF);
29 }
30 return vchRet;
31 }
32 33 vchRet.push_back(address.GetNetClass());
34 int nStartByte{0};
35 int nBits{0};
36 37 if (address.IsLocal()) {
38 // all local addresses belong to the same group
39 } else if (address.IsInternal()) {
40 // All internal-usage addresses get their own group.
41 // Skip over the INTERNAL_IN_IPV6_PREFIX returned by CAddress::GetAddrBytes().
42 nStartByte = INTERNAL_IN_IPV6_PREFIX.size();
43 nBits = ADDR_INTERNAL_SIZE * 8;
44 } else if (!address.IsRoutable()) {
45 // all other unroutable addresses belong to the same group
46 } else if (address.HasLinkedIPv4()) {
47 // IPv4 addresses (and mapped IPv4 addresses) use /16 groups
48 uint32_t ipv4 = address.GetLinkedIPv4();
49 vchRet.push_back((ipv4 >> 24) & 0xFF);
50 vchRet.push_back((ipv4 >> 16) & 0xFF);
51 return vchRet;
52 } else if (address.IsTor() || address.IsI2P()) {
53 nBits = 4;
54 } else if (address.IsCJDNS()) {
55 // Treat in the same way as Tor and I2P because the address in all of
56 // them is "random" bytes (derived from a public key). However in CJDNS
57 // the first byte is a constant (see CJDNS_PREFIX), so the random bytes
58 // come after it. Thus skip the constant 8 bits at the start.
59 nBits = 12;
60 } else if (address.IsHeNet()) {
61 // for he.net, use /36 groups
62 nBits = 36;
63 } else {
64 // for the rest of the IPv6 network, use /32 groups
65 nBits = 32;
66 }
67 68 // Push our address onto vchRet.
69 auto addr_bytes = address.GetAddrBytes();
70 const size_t num_bytes = nBits / 8;
71 vchRet.insert(vchRet.end(), addr_bytes.begin() + nStartByte, addr_bytes.begin() + nStartByte + num_bytes);
72 nBits %= 8;
73 // ...for the last byte, push nBits and for the rest of the byte push 1's
74 if (nBits > 0) {
75 assert(num_bytes < addr_bytes.size());
76 vchRet.push_back(addr_bytes[num_bytes + nStartByte] | ((1 << (8 - nBits)) - 1));
77 }
78 79 return vchRet;
80 }
81 82 uint32_t NetGroupManager::GetMappedAS(const CNetAddr& address) const
83 {
84 uint32_t net_class = address.GetNetClass();
85 if (m_asmap.empty() || (net_class != NET_IPV4 && net_class != NET_IPV6)) {
86 return 0; // Indicates not found, safe because AS0 is reserved per RFC7607.
87 }
88 std::vector<std::byte> ip_bytes(16);
89 if (address.HasLinkedIPv4()) {
90 // For lookup, treat as if it was just an IPv4 address (IPV4_IN_IPV6_PREFIX + IPv4 bits)
91 std::copy_n(std::as_bytes(std::span{IPV4_IN_IPV6_PREFIX}).begin(),
92 IPV4_IN_IPV6_PREFIX.size(), ip_bytes.begin());
93 uint32_t ipv4 = address.GetLinkedIPv4();
94 for (int i = 0; i < 4; ++i) {
95 ip_bytes[12 + i] = std::byte((ipv4 >> (24 - i * 8)) & 0xFF);
96 }
97 } else {
98 // Use all 128 bits of the IPv6 address otherwise
99 assert(address.IsIPv6());
100 auto addr_bytes = address.GetAddrBytes();
101 assert(addr_bytes.size() == ip_bytes.size());
102 std::copy_n(std::as_bytes(std::span{addr_bytes}).begin(),
103 addr_bytes.size(), ip_bytes.begin());
104 }
105 uint32_t mapped_as = Interpret(m_asmap, ip_bytes);
106 return mapped_as;
107 }
108 109 void NetGroupManager::ASMapHealthCheck(const std::vector<CNetAddr>& clearnet_addrs) const {
110 std::set<uint32_t> clearnet_asns{};
111 int unmapped_count{0};
112 113 for (const auto& addr : clearnet_addrs) {
114 uint32_t asn = GetMappedAS(addr);
115 if (asn == 0) {
116 ++unmapped_count;
117 continue;
118 }
119 clearnet_asns.insert(asn);
120 }
121 122 LogInfo("ASMap Health Check: %i clearnet peers are mapped to %i ASNs with %i peers being unmapped\n", clearnet_addrs.size(), clearnet_asns.size(), unmapped_count);
123 }
124 125 bool NetGroupManager::UsingASMap() const {
126 return m_asmap.size() > 0;
127 }
128