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Use ASNs for mapped IPv4 addresses correctly

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This commit is contained in:
Pieter Wuille 2020-01-29 15:02:26 -08:00
parent 6f8c937312
commit 38c2395d7a
2 changed files with 61 additions and 41 deletions
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97
src/netaddress.cpp
View File

@ -401,6 +401,26 @@ bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
return true;
}
bool CNetAddr::HasLinkedIPv4() const
{
return IsRoutable() && (IsIPv4() || IsRFC6145() || IsRFC6052() || IsRFC3964() || IsRFC4380());
}
uint32_t CNetAddr::GetLinkedIPv4() const
{
if (IsIPv4() || IsRFC6145() || IsRFC6052()) {
// IPv4, mapped IPv4, SIIT translated IPv4: the IPv4 address is the last 4 bytes of the address
return ReadBE32(ip + 12);
} else if (IsRFC3964()) {
// 6to4 tunneled IPv4: the IPv4 address is in bytes 2-6
return ReadBE32(ip + 2);
} else if (IsRFC4380()) {
// Teredo tunneled IPv4: the IPv4 address is in the last 4 bytes of the address, but bitflipped
return ~ReadBE32(ip + 12);
}
assert(false);
}
uint32_t CNetAddr::GetNetClass() const {
uint32_t net_class = NET_IPV6;
if (IsLocal()) {
@ -410,7 +430,7 @@ uint32_t CNetAddr::GetNetClass() const {
net_class = NET_INTERNAL;
} else if (!IsRoutable()) {
net_class = NET_UNROUTABLE;
} else if (IsIPv4() || IsRFC6145() || IsRFC6052() || IsRFC3964() || IsRFC4380()) {
} else if (HasLinkedIPv4()) {
net_class = NET_IPV4;
} else if (IsTor()) {
net_class = NET_ONION;
@ -424,10 +444,24 @@ uint32_t CNetAddr::GetMappedAS(const std::vector<bool> &asmap) const {
return 0; // Indicates not found, safe because AS0 is reserved per RFC7607.
}
std::vector<bool> ip_bits(128);
for (int8_t byte_i = 0; byte_i < 16; ++byte_i) {
uint8_t cur_byte = GetByte(15 - byte_i);
for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
ip_bits[byte_i * 8 + bit_i] = (cur_byte >> (7 - bit_i)) & 1;
if (HasLinkedIPv4()) {
// For lookup, treat as if it was just an IPv4 address (pchIPv4 prefix + IPv4 bits)
for (int8_t byte_i = 0; byte_i < 12; ++byte_i) {
for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
ip_bits[byte_i * 8 + bit_i] = (pchIPv4[byte_i] >> (7 - bit_i)) & 1;
}
}
uint32_t ipv4 = GetLinkedIPv4();
for (int i = 0; i < 32; ++i) {
ip_bits[96 + i] = (ipv4 >> (31 - i)) & 1;
}
} else {
// Use all 128 bits of the IPv6 address otherwise
for (int8_t byte_i = 0; byte_i < 16; ++byte_i) {
uint8_t cur_byte = GetByte(15 - byte_i);
for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
ip_bits[byte_i * 8 + bit_i] = (cur_byte >> (7 - bit_i)) & 1;
}
}
}
uint32_t mapped_as = Interpret(asmap, ip_bits);
@ -463,51 +497,32 @@ std::vector<unsigned char> CNetAddr::GetGroup(const std::vector<bool> &asmap) co
int nStartByte = 0;
int nBits = 16;
// all local addresses belong to the same group
if (IsLocal())
{
if (IsLocal()) {
// all local addresses belong to the same group
nBits = 0;
}
// all internal-usage addresses get their own group
if (IsInternal())
{
} else if (IsInternal()) {
// all internal-usage addresses get their own group
nStartByte = sizeof(g_internal_prefix);
nBits = (sizeof(ip) - sizeof(g_internal_prefix)) * 8;
}
// all other unroutable addresses belong to the same group
else if (!IsRoutable())
{
} else if (!IsRoutable()) {
// all other unroutable addresses belong to the same group
nBits = 0;
}
// for IPv4 addresses, '1' + the 16 higher-order bits of the IP
// includes mapped IPv4, SIIT translated IPv4, and the well-known prefix
else if (IsIPv4() || IsRFC6145() || IsRFC6052())
{
nStartByte = 12;
}
// for 6to4 tunnelled addresses, use the encapsulated IPv4 address
else if (IsRFC3964())
{
nStartByte = 2;
}
// for Teredo-tunnelled IPv6 addresses, use the encapsulated IPv4 address
else if (IsRFC4380())
{
vchRet.push_back(GetByte(3) ^ 0xFF);
vchRet.push_back(GetByte(2) ^ 0xFF);
} else if (HasLinkedIPv4()) {
// IPv4 addresses (and mapped IPv4 addresses) use /16 groups
uint32_t ipv4 = GetLinkedIPv4();
vchRet.push_back((ipv4 >> 24) & 0xFF);
vchRet.push_back((ipv4 >> 16) & 0xFF);
return vchRet;
}
else if (IsTor())
{
} else if (IsTor()) {
nStartByte = 6;
nBits = 4;
}
// for he.net, use /36 groups
else if (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x04 && GetByte(12) == 0x70)
} else if (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x04 && GetByte(12) == 0x70) {
// for he.net, use /36 groups
nBits = 36;
// for the rest of the IPv6 network, use /32 groups
else
} else {
// for the rest of the IPv6 network, use /32 groups
nBits = 32;
}
// push our ip onto vchRet byte by byte...
while (nBits >= 8)

5
src/netaddress.h
View File

@ -80,6 +80,11 @@ class CNetAddr
bool GetInAddr(struct in_addr* pipv4Addr) const;
uint32_t GetNetClass() const;
//! For IPv4, mapped IPv4, SIIT translated IPv4, Teredo, 6to4 tunneled addresses, return the relevant IPv4 address as a uint32.
uint32_t GetLinkedIPv4() const;
//! Whether this address has a linked IPv4 address (see GetLinkedIPv4()).
bool HasLinkedIPv4() const;
// The AS on the BGP path to the node we use to diversify
// peers in AddrMan bucketing based on the AS infrastructure.
// The ip->AS mapping depends on how asmap is constructed.