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net: change CNetAddr::ip to have flexible size

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Before this change `CNetAddr::ip` was a fixed-size array of 16 bytes,
not being able to store larger addresses (e.g. TORv3) and encoded
smaller ones as 16-byte IPv6 addresses.

Change its type to `prevector`, so that it can hold larger addresses and
do not disguise non-IPv6 addresses as IPv6. So the IPv4 address
`1.2.3.4` is now encoded as `01020304` instead of
`00000000000000000000FFFF01020304`.

Rename `CNetAddr::ip` to `CNetAddr::m_addr` because it is not an "IP" or
"IP address" (TOR addresses are not IP addresses).

In order to preserve backward compatibility with serialization (where
e.g. `1.2.3.4` is serialized as `00000000000000000000FFFF01020304`)
introduce `CNetAddr` dedicated legacy serialize/unserialize methods.

Adjust `CSubNet` accordingly. Still use `CSubNet::netmask[]` of fixed 16
bytes, but use the first 4 for IPv4 (not the last 4). Only allow
subnetting for IPv4 and IPv6.

Co-authored-by: Carl Dong <contact@carldong.me>
This commit is contained in:
Vasil Dimov
2020-08-24 21:34:26 +02:00
parent 1ea57ad674
commit 102867c587
10 changed files with 452 additions and 217 deletions
Download Patch File Download Diff File Expand all files Collapse all files

158
src/netaddress.h
View File

@@ -9,9 +9,12 @@
#include <config/bitcoin-config.h>
#endif
#include <attributes.h>
#include <compat.h>
#include <prevector.h>
#include <serialize.h>
#include <array>
#include <cstdint>
#include <string>
#include <vector>
@@ -39,28 +42,66 @@ enum Network
/// TORv2
NET_ONION,
/// A set of dummy addresses that map a name to an IPv6 address. These
/// addresses belong to RFC4193's fc00::/7 subnet (unique-local addresses).
/// We use them to map a string or FQDN to an IPv6 address in CAddrMan to
/// keep track of which DNS seeds were used.
/// A set of addresses that represent the hash of a string or FQDN. We use
/// them in CAddrMan to keep track of which DNS seeds were used.
NET_INTERNAL,
/// Dummy value to indicate the number of NET_* constants.
NET_MAX,
};
/// Prefix of an IPv6 address when it contains an embedded IPv4 address.
/// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
static const std::array<uint8_t, 12> IPV4_IN_IPV6_PREFIX{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF
};
/// Prefix of an IPv6 address when it contains an embedded TORv2 address.
/// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
/// Such dummy IPv6 addresses are guaranteed to not be publicly routable as they
/// fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
static const std::array<uint8_t, 6> TORV2_IN_IPV6_PREFIX{
0xFD, 0x87, 0xD8, 0x7E, 0xEB, 0x43
};
/// Prefix of an IPv6 address when it contains an embedded "internal" address.
/// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
/// The prefix comes from 0xFD + SHA256("bitcoin")[0:5].
/// Such dummy IPv6 addresses are guaranteed to not be publicly routable as they
/// fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
static const std::array<uint8_t, 6> INTERNAL_IN_IPV6_PREFIX{
0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24 // 0xFD + sha256("bitcoin")[0:5].
};
/// Size of IPv4 address (in bytes).
static constexpr size_t ADDR_IPV4_SIZE = 4;
/// Size of IPv6 address (in bytes).
static constexpr size_t ADDR_IPV6_SIZE = 16;
/// Size of TORv2 address (in bytes).
static constexpr size_t ADDR_TORV2_SIZE = 10;
/// Size of "internal" (NET_INTERNAL) address (in bytes).
static constexpr size_t ADDR_INTERNAL_SIZE = 10;
/**
* Network address.
*/
class CNetAddr
{
protected:
/**
* Raw representation of the network address.
* In network byte order (big endian) for IPv4 and IPv6.
*/
prevector<ADDR_IPV6_SIZE, uint8_t> m_addr{ADDR_IPV6_SIZE, 0x0};
/**
* Network to which this address belongs.
*/
Network m_net{NET_IPV6};
unsigned char ip[16]; // in network byte order
uint32_t scopeId{0}; // for scoped/link-local ipv6 addresses
public:
@@ -74,13 +115,7 @@ class CNetAddr
* (e.g. IPv4) disguised as IPv6. This encoding is used in the legacy
* `addr` encoding.
*/
void SetLegacyIPv6(const uint8_t ipv6[16]);
/**
* Set raw IPv4 or IPv6 address (in network byte order)
* @note Only NET_IPV4 and NET_IPV6 are allowed for network.
*/
void SetRaw(Network network, const uint8_t *data);
void SetLegacyIPv6(Span<const uint8_t> ipv6);
bool SetInternal(const std::string& name);
@@ -111,7 +146,6 @@ class CNetAddr
enum Network GetNetwork() const;
std::string ToString() const;
std::string ToStringIP() const;
unsigned int GetByte(int n) const;
uint64_t GetHash() const;
bool GetInAddr(struct in_addr* pipv4Addr) const;
uint32_t GetNetClass() const;
@@ -127,7 +161,7 @@ class CNetAddr
uint32_t GetMappedAS(const std::vector<bool> &asmap) const;
std::vector<unsigned char> GetGroup(const std::vector<bool> &asmap) const;
std::vector<unsigned char> GetAddrBytes() const { return {std::begin(ip), std::end(ip)}; }
std::vector<unsigned char> GetAddrBytes() const;
int GetReachabilityFrom(const CNetAddr *paddrPartner = nullptr) const;
explicit CNetAddr(const struct in6_addr& pipv6Addr, const uint32_t scope = 0);
@@ -143,7 +177,7 @@ class CNetAddr
template <typename Stream>
void Serialize(Stream& s) const
{
s << ip;
SerializeV1Stream(s);
}
/**
@@ -152,14 +186,92 @@ class CNetAddr
template <typename Stream>
void Unserialize(Stream& s)
{
unsigned char ip_temp[sizeof(ip)];
s >> ip_temp;
// Use SetLegacyIPv6() so that m_net is set correctly. For example
// ::FFFF:0102:0304 should be set as m_net=NET_IPV4 (1.2.3.4).
SetLegacyIPv6(ip_temp);
UnserializeV1Stream(s);
}
friend class CSubNet;
private:
/**
* Size of CNetAddr when serialized as ADDRv1 (pre-BIP155) (in bytes).
*/
static constexpr size_t V1_SERIALIZATION_SIZE = ADDR_IPV6_SIZE;
/**
* Serialize in pre-ADDRv2/BIP155 format to an array.
* Some addresses (e.g. TORv3) cannot be serialized in pre-BIP155 format.
*/
void SerializeV1Array(uint8_t (&arr)[V1_SERIALIZATION_SIZE]) const
{
size_t prefix_size;
switch (m_net) {
case NET_IPV6:
assert(m_addr.size() == sizeof(arr));
memcpy(arr, m_addr.data(), m_addr.size());
return;
case NET_IPV4:
prefix_size = sizeof(IPV4_IN_IPV6_PREFIX);
assert(prefix_size + m_addr.size() == sizeof(arr));
memcpy(arr, IPV4_IN_IPV6_PREFIX.data(), prefix_size);
memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
return;
case NET_ONION:
prefix_size = sizeof(TORV2_IN_IPV6_PREFIX);
assert(prefix_size + m_addr.size() == sizeof(arr));
memcpy(arr, TORV2_IN_IPV6_PREFIX.data(), prefix_size);
memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
return;
case NET_INTERNAL:
prefix_size = sizeof(INTERNAL_IN_IPV6_PREFIX);
assert(prefix_size + m_addr.size() == sizeof(arr));
memcpy(arr, INTERNAL_IN_IPV6_PREFIX.data(), prefix_size);
memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
return;
case NET_UNROUTABLE:
case NET_MAX:
assert(false);
} // no default case, so the compiler can warn about missing cases
assert(false);
}
/**
* Serialize in pre-ADDRv2/BIP155 format to a stream.
* Some addresses (e.g. TORv3) cannot be serialized in pre-BIP155 format.
*/
template <typename Stream>
void SerializeV1Stream(Stream& s) const
{
uint8_t serialized[V1_SERIALIZATION_SIZE];
SerializeV1Array(serialized);
s << serialized;
}
/**
* Unserialize from a pre-ADDRv2/BIP155 format from an array.
*/
void UnserializeV1Array(uint8_t (&arr)[V1_SERIALIZATION_SIZE])
{
// Use SetLegacyIPv6() so that m_net is set correctly. For example
// ::FFFF:0102:0304 should be set as m_net=NET_IPV4 (1.2.3.4).
SetLegacyIPv6(arr);
}
/**
* Unserialize from a pre-ADDRv2/BIP155 format from a stream.
*/
template <typename Stream>
void UnserializeV1Stream(Stream& s)
{
uint8_t serialized[V1_SERIALIZATION_SIZE];
s >> serialized;
UnserializeV1Array(serialized);
}
};
class CSubNet
@@ -174,11 +286,11 @@ class CSubNet
public:
CSubNet();
CSubNet(const CNetAddr &addr, int32_t mask);
CSubNet(const CNetAddr &addr, const CNetAddr &mask);
CSubNet(const CNetAddr& addr, uint8_t mask);
CSubNet(const CNetAddr& addr, const CNetAddr& mask);
//constructor for single ip subnet (<ipv4>/32 or <ipv6>/128)
explicit CSubNet(const CNetAddr &addr);
explicit CSubNet(const CNetAddr& addr);
bool Match(const CNetAddr &addr) const;