1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
// 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 "dandelionpp.h"
#include <boost/container/small_vector.hpp>
#include <boost/uuid/nil_generator.hpp>
#include <chrono>
#include "common/expect.h"
#include "cryptonote_config.h"
#include "crypto/crypto.h"
namespace net
{
namespace dandelionpp
{
namespace
{
constexpr const std::size_t expected_max_channels = CRYPTONOTE_NOISE_CHANNELS;
// could be in util somewhere
struct key_less
{
template<typename K, typename V>
bool operator()(const std::pair<K, V>& left, const K& right) const
{
return left.first < right;
}
template<typename K, typename V>
bool operator()(const K& left, const std::pair<K, V>& right) const
{
return left < right.first;
}
};
std::size_t select_stem(epee::span<const std::size_t> usage, epee::span<const boost::uuids::uuid> out_map)
{
assert(usage.size() < std::numeric_limits<std::size_t>::max()); // prevented in constructor
if (usage.size() < out_map.size())
return std::numeric_limits<std::size_t>::max();
// small_vector uses stack space if `expected_max_channels < capacity()`
std::size_t lowest = std::numeric_limits<std::size_t>::max();
boost::container::small_vector<std::size_t, expected_max_channels> choices;
static_assert(sizeof(choices) < 256, "choices is too large based on current configuration");
for (const boost::uuids::uuid& out : out_map)
{
if (!out.is_nil())
{
const std::size_t location = std::addressof(out) - out_map.begin();
if (usage[location] < lowest)
{
lowest = usage[location];
choices = {location};
}
else if (usage[location] == lowest)
choices.push_back(location);
}
}
switch (choices.size())
{
case 0:
return std::numeric_limits<std::size_t>::max();
case 1:
return choices[0];
default:
break;
}
return choices[crypto::rand_idx(choices.size())];
}
} // anonymous
connection_map::connection_map(std::vector<boost::uuids::uuid> out_connections, const std::size_t stems)
: out_mapping_(std::move(out_connections)),
in_mapping_(),
usage_count_()
{
// max value is used by `select_stem` as error case
if (stems == std::numeric_limits<std::size_t>::max())
MONERO_THROW(common_error::kInvalidArgument, "stems value cannot be max size_t");
usage_count_.resize(stems);
if (stems < out_mapping_.size())
{
for (unsigned i = 0; i < stems; ++i)
std::swap(out_mapping_[i], out_mapping_.at(i + crypto::rand_idx(out_mapping_.size() - i)));
out_mapping_.resize(stems);
}
else
{
std::shuffle(out_mapping_.begin(), out_mapping_.end(), crypto::random_device{});
}
}
connection_map::~connection_map() noexcept
{}
connection_map connection_map::clone() const
{
return {*this};
}
bool connection_map::update(std::vector<boost::uuids::uuid> current)
{
std::sort(current.begin(), current.end());
bool replace = false;
for (auto& existing_out : out_mapping_)
{
const auto elem = std::lower_bound(current.begin(), current.end(), existing_out);
if (elem == current.end() || *elem != existing_out)
{
existing_out = boost::uuids::nil_uuid();
replace = true;
}
else // already using connection, remove it from candidate list
current.erase(elem);
}
if (!replace && out_mapping_.size() == usage_count_.size())
return false;
const std::size_t existing_outs = out_mapping_.size();
for (std::size_t i = 0; i < usage_count_.size() && !current.empty(); ++i)
{
const bool increase_stems = out_mapping_.size() <= i;
if (increase_stems || out_mapping_[i].is_nil())
{
std::swap(current.back(), current.at(crypto::rand_idx(current.size())));
if (increase_stems)
out_mapping_.push_back(current.back());
else
out_mapping_[i] = current.back();
current.pop_back();
}
}
return replace || existing_outs < out_mapping_.size();
}
std::size_t connection_map::size() const noexcept
{
std::size_t count = 0;
for (const boost::uuids::uuid& connection : out_mapping_)
{
if (!connection.is_nil())
++count;
}
return count;
}
boost::uuids::uuid connection_map::get_stem(const boost::uuids::uuid& source)
{
auto elem = std::lower_bound(in_mapping_.begin(), in_mapping_.end(), source, key_less{});
if (elem == in_mapping_.end() || elem->first != source)
{
const std::size_t index = select_stem(epee::to_span(usage_count_), epee::to_span(out_mapping_));
if (out_mapping_.size() < index)
return boost::uuids::nil_uuid();
elem = in_mapping_.emplace(elem, source, index);
usage_count_[index]++;
}
else if (out_mapping_.at(elem->second).is_nil()) // stem connection disconnected after mapping
{
usage_count_.at(elem->second)--;
const std::size_t index = select_stem(epee::to_span(usage_count_), epee::to_span(out_mapping_));
if (out_mapping_.size() < index)
{
in_mapping_.erase(elem);
return boost::uuids::nil_uuid();
}
elem->second = index;
usage_count_[index]++;
}
return out_mapping_[elem->second];
}
} // dandelionpp
} // net
|
