i2p: initial support

ANONYMITY_NETWORKS.md

@@ -1,7 +1,6 @@
 # Anonymity Networks with Monero
 
-Currently only Tor has been integrated into Monero. Providing support for
-Kovri/I2P should be minimal, but has not yet been attempted. The usage of
+Currently only Tor and I2P have been integrated into Monero. The usage of
 these networks is still considered experimental - there are a few pessimistic
 cases where privacy is leaked. The design is intended to maximize privacy of
 the source of a transaction by broadcasting it over an anonymity network, while
@@ -23,8 +22,8 @@ connections enabled.
 
 ## P2P Commands
 
-Only handshakes, peer timed syncs, and transaction broadcast messages are
-supported over anonymity networks. If one `--add-exclusive-node` onion address
+Only handshakes, peer timed syncs and transaction broadcast messages are
+supported over anonymity networks. If one `--add-exclusive-node` p2p address
 is specified, then no syncing will take place and only transaction broadcasting
 can occur. It is therefore recommended that `--add-exclusive-node` be combined
 with additional exclusive IPv4 address(es).
@@ -47,9 +46,9 @@ separate process. On most systems the configuration will look like:
 
 which tells `monerod` that ".onion" p2p addresses can be forwarded to a socks
 proxy at IP 127.0.0.1 port 9050 with a max of 10 outgoing connections and
-".i2p" p2p addresses can be forwarded to a socks proxy at IP 127.0.0.1 port 9000
-with the default max outgoing connections. Since there are no seed nodes for
-anonymity connections, peers must be manually specified:
+".b32.i2p" p2p addresses can be forwarded to a socks proxy at IP 127.0.0.1 port
+9000 with the default max outgoing connections. Since there are no seed nodes
+for anonymity connections, peers must be manually specified:
 
 > `--add-exclusive-node rveahdfho7wo4b2m.onion:28083`
 > `--add-peer rveahdfho7wo4b2m.onion:28083`
@@ -64,27 +63,28 @@ Receiving anonymity connections is done through the option
 `--anonymous-inbound`. This option tells `monerod` the inbound address, network
 type, and max connections:
 
-> `--anonymous-inbound rveahdfho7wo4b2m.onion:28083,127.0.0.28083,25`
-> `--anonymous-inbound foobar.i2p:5000,127.0.0.1:30000`
+> `--anonymous-inbound rveahdfho7wo4b2m.onion:28083,127.0.0.1:28083,25`
+> `--anonymous-inbound cmeua5767mz2q5jsaelk2rxhf67agrwuetaso5dzbenyzwlbkg2q.b32.i2p:5000,127.0.0.1:30000`
 
 which tells `monerod` that a max of 25 inbound Tor connections are being
 received at address "rveahdfho7wo4b2m.onion:28083" and forwarded to `monerod`
 localhost port 28083, and a default max I2P connections are being received at
-address "foobar.i2p:5000" and forwarded to `monerod` localhost port 30000.
+address "cmeua5767mz2q5jsaelk2rxhf67agrwuetaso5dzbenyzwlbkg2q.b32.i2p:5000" and
+forwarded to `monerod` localhost port 30000.
 These addresses will be shared with outgoing peers, over the same network type,
 otherwise the peer will not be notified of the peer address by the proxy.
 
 ### Network Types
 
-#### Tor
+#### Tor & I2P
 
-Options `--add-exclusive-node` and `--add-peer` recognize ".onion" addresses,
-and will properly forward those addresses to the proxy provided with
-`--proxy tor,...`.
+Options `--add-exclusive-node` and `--add-peer` recognize ".onion" and
+".b32.i2p" addresses, and will properly forward those addresses to the proxy
+provided with `--proxy tor,...` or `--proxy i2p,...`.
 
-Option `--anonymous-inbound` also recognizes ".onion" addresses, and will
-automatically be sent out to outgoing Tor connections so the peer can
-distribute the address to its other peers.
+Option `--anonymous-inbound` also recognizes ".onion" and ".b32.i2p" addresses,
+and will automatically be sent out to outgoing Tor/I2P connections so the peer
+can distribute the address to its other peers.
 
 ##### Configuration
 
@@ -99,11 +99,8 @@ This will store key information in `/var/lib/tor/data/monero` and will forward
 `/usr/lib/tor/data/monero/hostname` will contain the ".onion" address for use
 with `--anonymous-inbound`.
 
-#### Kovri/I2P
-
-Support for this network has not been implemented. Using ".i2p" addresses or
-specifying "i2p" will currently generate an error.
-
+I2P must be configured with a standard server tunnel. Configuration differs by
+I2P implementation.
 
 ## Privacy Limitations
 
@@ -132,11 +129,11 @@ more difficult.
 ### Bandwidth Usage
 
 An ISP can passively monitor `monerod` connections from a node and observe when
-a transaction is sent over a Tor/Kovri connection via timing analysis + size of
-data sent during that timeframe. Kovri should provide better protection against
+a transaction is sent over a Tor/I2P connection via timing analysis + size of
+data sent during that timeframe. I2P should provide better protection against
 this attack - its connections are not circuit based. However, if a node is
-only using Kovri for broadcasting Monero transactions, the total aggregate of
-Kovri/I2P data would also leak information.
+only using I2P for broadcasting Monero transactions, the total aggregate of
+I2P data would also leak information.
 
 #### Mitigation
 
@@ -165,15 +162,15 @@ simply a best effort attempt.
 ### Active Bandwidth Shaping
 
 An attacker could attempt to bandwidth shape traffic in an attempt to determine
-the source of a Tor/Kovri/I2P connection. There isn't great mitigation against
-this, but Kovri/I2P should provide better protection against this attack since
+the source of a Tor/I2P connection. There isn't great mitigation against
+this, but I2P should provide better protection against this attack since
 the connections are not circuit based.
 
 #### Mitigation
 
-The best mitigiation is to use Kovri/I2P instead of Tor. However, Kovri/I2P
+The best mitigiation is to use I2P instead of Tor. However, I2P
 has a smaller set of users (less cover traffic) and academic reviews, so there
 is a tradeoff in potential isses. Also, anyone attempting this strategy really
 wants to uncover a user, it seems unlikely that this would be performed against
-every Tor/Kovri/I2P user.
+every Tor/I2P user.
 

contrib/epee/include/net/net_utils_base.h

@@ -47,6 +47,7 @@
 namespace net
 {
 	class tor_address;
+	class i2p_address;
 }
 
 namespace epee
@@ -196,7 +197,7 @@ namespace net_utils
 		template<typename Type> const Type &as() const { return as_mutable<const Type>(); }
 
 		BEGIN_KV_SERIALIZE_MAP()
-			// need to `#include "net/tor_address.h"` when serializing `network_address`
+			// need to `#include "net/[i2p|tor]_address.h"` when serializing `network_address`
 			static constexpr std::integral_constant<bool, is_store> is_store_{};
 
 			std::uint8_t type = std::uint8_t(is_store ? this_ref.get_type_id() : address_type::invalid);
@@ -209,6 +210,8 @@ namespace net_utils
 					return this_ref.template serialize_addr<ipv4_network_address>(is_store_, stg, hparent_section);
 				case address_type::tor:
 					return this_ref.template serialize_addr<net::tor_address>(is_store_, stg, hparent_section);
+				case address_type::i2p:
+					return this_ref.template serialize_addr<net::i2p_address>(is_store_, stg, hparent_section);
 				case address_type::invalid:
 				default:
 					break;

src/cryptonote_config.h

@@ -108,7 +108,7 @@
 #define P2P_DEFAULT_PACKET_MAX_SIZE                     50000000     //50000000 bytes maximum packet size
 #define P2P_DEFAULT_PEERS_IN_HANDSHAKE                  250
 #define P2P_DEFAULT_CONNECTION_TIMEOUT                  5000       //5 seconds
-#define P2P_DEFAULT_TOR_CONNECT_TIMEOUT                 20         // seconds
+#define P2P_DEFAULT_SOCKS_CONNECT_TIMEOUT               45         // seconds
 #define P2P_DEFAULT_PING_CONNECTION_TIMEOUT             2000       //2 seconds
 #define P2P_DEFAULT_INVOKE_TIMEOUT                      60*2*1000  //2 minutes
 #define P2P_DEFAULT_HANDSHAKE_INVOKE_TIMEOUT            5000       //5 seconds

src/net/CMakeLists.txt

@@ -26,8 +26,8 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-set(net_sources error.cpp parse.cpp socks.cpp tor_address.cpp)
-set(net_headers error.h parse.h socks.h tor_address.h)
+set(net_sources error.cpp parse.cpp socks.cpp tor_address.cpp i2p_address.cpp)
+set(net_headers error.h parse.h socks.h tor_address.h i2p_address.h)
 
 monero_add_library(net ${net_sources} ${net_headers})
 target_link_libraries(net epee ${Boost_ASIO_LIBRARY})

src/net/fwd.h

@@ -34,6 +34,7 @@ namespace net
 {
     enum class error : int;
     class tor_address;
+    class i2p_address;
 
     namespace socks
     {

src/net/i2p_address.cpp

@@ -0,0 +1,200 @@
+// Copyright (c) 2019, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "i2p_address.h"
+
+#include <algorithm>
+#include <boost/spirit/include/karma_generate.hpp>
+#include <boost/spirit/include/karma_uint.hpp>
+#include <cassert>
+#include <cstring>
+#include <limits>
+
+#include "net/error.h"
+#include "serialization/keyvalue_serialization.h"
+#include "storages/portable_storage.h"
+#include "string_tools.h"
+
+namespace net
+{
+    namespace
+    {
+        // !TODO only b32 addresses right now
+        constexpr const char tld[] = u8".b32.i2p";
+        constexpr const char unknown_host[] = "<unknown i2p host>";
+
+        constexpr const unsigned b32_length = 52;
+
+        constexpr const char base32_alphabet[] =
+            u8"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz234567";
+
+        expect<void> host_check(boost::string_ref host) noexcept
+        {
+            if (!host.ends_with(tld))
+                return {net::error::expected_tld};
+
+            host.remove_suffix(sizeof(tld) - 1);
+
+            if (host.size() != b32_length)
+                return {net::error::invalid_i2p_address};
+            if (host.find_first_not_of(base32_alphabet) != boost::string_ref::npos)
+                return {net::error::invalid_i2p_address};
+
+            return success();
+        }
+
+        struct i2p_serialized
+        {
+            std::string host;
+            std::uint16_t port;
+
+            BEGIN_KV_SERIALIZE_MAP()
+                KV_SERIALIZE(host)
+                KV_SERIALIZE(port)
+            END_KV_SERIALIZE_MAP()
+        };
+    }
+
+    i2p_address::i2p_address(const boost::string_ref host, const std::uint16_t port) noexcept
+      : port_(port)
+    {
+        // this is a private constructor, throw if moved to public
+        assert(host.size() < sizeof(host_));
+
+        const std::size_t length = std::min(sizeof(host_) - 1, host.size());
+        std::memcpy(host_, host.data(), length);
+        std::memset(host_ + length, 0, sizeof(host_) - length);
+    }
+
+    const char* i2p_address::unknown_str() noexcept
+    {
+        return unknown_host;
+    }
+
+    i2p_address::i2p_address() noexcept
+      : port_(0)
+    {
+        static_assert(sizeof(unknown_host) <= sizeof(host_), "bad buffer size");
+        std::memcpy(host_, unknown_host, sizeof(unknown_host));
+        std::memset(host_ + sizeof(unknown_host), 0, sizeof(host_) - sizeof(unknown_host));
+    }
+
+    expect<i2p_address> i2p_address::make(const boost::string_ref address, const std::uint16_t default_port)
+    {
+        boost::string_ref host = address.substr(0, address.rfind(':'));
+        const boost::string_ref port =
+            address.substr(host.size() + (host.size() == address.size() ? 0 : 1));
+
+        MONERO_CHECK(host_check(host));
+
+        std::uint16_t porti = default_port;
+        if (!port.empty() && !epee::string_tools::get_xtype_from_string(porti, std::string{port}))
+            return {net::error::invalid_port};
+
+        static_assert(b32_length + sizeof(tld) == sizeof(i2p_address::host_), "bad internal host size");
+        return i2p_address{host, porti};
+    }
+
+    bool i2p_address::_load(epee::serialization::portable_storage& src, epee::serialization::section* hparent)
+    {
+        i2p_serialized in{};
+        if (in._load(src, hparent) && in.host.size() < sizeof(host_) && (in.host == unknown_host || !host_check(in.host).has_error()))
+        {
+            std::memcpy(host_, in.host.data(), in.host.size());
+            std::memset(host_ + in.host.size(), 0, sizeof(host_) - in.host.size());
+            port_ = in.port;
+            return true;
+        }
+        static_assert(sizeof(unknown_host) <= sizeof(host_), "bad buffer size");
+        std::memcpy(host_, unknown_host, sizeof(unknown_host)); // include null terminator
+        port_ = 0;
+        return false;
+    }
+
+    bool i2p_address::store(epee::serialization::portable_storage& dest, epee::serialization::section* hparent) const
+    {
+        const i2p_serialized out{std::string{host_}, port_};
+        return out.store(dest, hparent);
+    }
+
+    i2p_address::i2p_address(const i2p_address& rhs) noexcept
+      : port_(rhs.port_)
+    {
+        std::memcpy(host_, rhs.host_, sizeof(host_));
+    }
+
+    i2p_address& i2p_address::operator=(const i2p_address& rhs) noexcept
+    {
+        if (this != std::addressof(rhs))
+        {
+            port_ = rhs.port_;
+            std::memcpy(host_, rhs.host_, sizeof(host_));
+        }
+        return *this;
+    }
+
+    bool i2p_address::is_unknown() const noexcept
+    {
+        static_assert(1 <= sizeof(host_), "host size too small");
+        return host_[0] == '<'; // character is not allowed otherwise
+    }
+
+    bool i2p_address::equal(const i2p_address& rhs) const noexcept
+    {
+        return port_ == rhs.port_ && is_same_host(rhs);
+    }
+
+    bool i2p_address::less(const i2p_address& rhs) const noexcept
+    {
+        return std::strcmp(host_str(), rhs.host_str()) < 0 || port() < rhs.port();
+    }
+
+    bool i2p_address::is_same_host(const i2p_address& rhs) const noexcept
+    {
+        return std::strcmp(host_str(), rhs.host_str()) == 0;
+    }
+
+    std::string i2p_address::str() const
+    {
+        const std::size_t host_length = std::strlen(host_str());
+        const std::size_t port_length =
+            port_ == 0 ? 0 : std::numeric_limits<std::uint16_t>::digits10 + 2;
+
+        std::string out{};
+        out.reserve(host_length + port_length);
+        out.assign(host_str(), host_length);
+
+        if (port_ != 0)
+        {
+            out.push_back(':');
+            namespace karma = boost::spirit::karma;
+            karma::generate(std::back_inserter(out), karma::ushort_, port());
+        }
+        return out;
+    }
+}