5 files changed, 157 insertions, 0 deletions
diff --git a/src/cryptonote_basic/CMakeLists.txt b/src/cryptonote_basic/CMakeLists.txt
index 5286256c7..c9fb1433c 100644
--- a/src/cryptonote_basic/CMakeLists.txt
+++ b/src/cryptonote_basic/CMakeLists.txt
@@ -43,6 +43,7 @@ set(cryptonote_basic_sources
   cryptonote_format_utils.cpp
   difficulty.cpp
   hardfork.cpp
+  merge_mining.cpp
   miner.cpp)
 
 set(cryptonote_basic_headers)
@@ -57,6 +58,7 @@ set(cryptonote_basic_private_headers
   cryptonote_format_utils.h
   difficulty.h
   hardfork.h
+  merge_mining.h
   miner.h
   tx_extra.h
   verification_context.h)
diff --git a/src/cryptonote_basic/cryptonote_format_utils.cpp b/src/cryptonote_basic/cryptonote_format_utils.cpp
index fcc96883b..259334b16 100644
--- a/src/cryptonote_basic/cryptonote_format_utils.cpp
+++ b/src/cryptonote_basic/cryptonote_format_utils.cpp
@@ -728,6 +728,25 @@ namespace cryptonote
     return true;
   }
   //---------------------------------------------------------------
+  bool add_mm_merkle_root_to_tx_extra(std::vector<uint8_t>& tx_extra, const crypto::hash& mm_merkle_root, size_t mm_merkle_tree_depth)
+  {
+    CHECK_AND_ASSERT_MES(mm_merkle_tree_depth < 32, false, "merge mining merkle tree depth should be less than 32");
+    size_t start_pos = tx_extra.size();
+    tx_extra.resize(tx_extra.size() + 3 + 32);
+    //write tag
+    tx_extra[start_pos] = TX_EXTRA_MERGE_MINING_TAG;
+    //write data size
+    ++start_pos;
+    tx_extra[start_pos] = 33;
+    //write depth varint (always one byte here)
+    ++start_pos;
+    tx_extra[start_pos] = mm_merkle_tree_depth;
+    //write data
+    ++start_pos;
+    memcpy(&tx_extra[start_pos], &mm_merkle_root, 32);
+    return true;
+  }
+  //---------------------------------------------------------------
   bool remove_field_from_tx_extra(std::vector<uint8_t>& tx_extra, const std::type_info &type)
   {
     if (tx_extra.empty())
diff --git a/src/cryptonote_basic/cryptonote_format_utils.h b/src/cryptonote_basic/cryptonote_format_utils.h
index 636a88b9a..b311bd2b2 100644
--- a/src/cryptonote_basic/cryptonote_format_utils.h
+++ b/src/cryptonote_basic/cryptonote_format_utils.h
@@ -83,6 +83,7 @@ namespace cryptonote
   std::vector<crypto::public_key> get_additional_tx_pub_keys_from_extra(const transaction_prefix& tx);
   bool add_additional_tx_pub_keys_to_extra(std::vector<uint8_t>& tx_extra, const std::vector<crypto::public_key>& additional_pub_keys);
   bool add_extra_nonce_to_tx_extra(std::vector<uint8_t>& tx_extra, const blobdata& extra_nonce);
+  bool add_mm_merkle_root_to_tx_extra(std::vector<uint8_t>& tx_extra, const crypto::hash& mm_merkle_root, size_t mm_merkle_tree_depth);
   bool remove_field_from_tx_extra(std::vector<uint8_t>& tx_extra, const std::type_info &type);
   void set_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash& payment_id);
   void set_encrypted_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash8& payment_id);
diff --git a/src/cryptonote_basic/merge_mining.cpp b/src/cryptonote_basic/merge_mining.cpp
new file mode 100644
index 000000000..fcc74859f
--- /dev/null
+++ b/src/cryptonote_basic/merge_mining.cpp
@@ -0,0 +1,95 @@
+// Copyright (c) 2020, 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 <string.h>
+#include "misc_log_ex.h"
+#include "int-util.h"
+#include "crypto/crypto.h"
+#include "common/util.h"
+#include "merge_mining.h"
+
+using namespace epee;
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "cn.mm"
+
+using namespace crypto;
+
+namespace cryptonote
+{
+
+//---------------------------------------------------------------
+uint32_t get_aux_slot(const crypto::hash &id, uint32_t nonce, uint32_t n_aux_chains)
+{
+  CHECK_AND_ASSERT_THROW_MES(n_aux_chains > 0, "n_aux_chains is 0");
+
+  uint8_t buf[HASH_SIZE + sizeof(uint32_t) + 1];
+  memcpy(buf, &id, HASH_SIZE);
+  uint32_t v = SWAP32LE(nonce);
+  memcpy(buf + HASH_SIZE, &v, sizeof(uint32_t));
+  buf[HASH_SIZE + sizeof(uint32_t)] = config::HASH_KEY_MM_SLOT;
+
+  crypto::hash res;
+  tools::sha256sum(buf, sizeof(buf), res);
+  v = *((const uint32_t*)&res);
+  return SWAP32LE(v) % n_aux_chains;
+}
+//---------------------------------------------------------------
+uint32_t get_path_from_aux_slot(uint32_t slot, uint32_t n_aux_chains)
+{
+  CHECK_AND_ASSERT_THROW_MES(n_aux_chains > 0, "n_aux_chains is 0");
+  CHECK_AND_ASSERT_THROW_MES(slot < n_aux_chains, "slot >= n_aux_chains");
+
+  uint32_t path = 0;
+  CHECK_AND_ASSERT_THROW_MES(tree_path(n_aux_chains, slot, &path), "Failed to get path from aux slot");
+  return path;
+}
+//---------------------------------------------------------------
+uint32_t encode_mm_depth(uint32_t n_aux_chains, uint32_t nonce)
+{
+  CHECK_AND_ASSERT_THROW_MES(n_aux_chains > 0, "n_aux_chains is 0");
+
+  // how many bits to we need to representing n_aux_chains - 1
+  uint32_t n_bits = 1;
+  while ((1u << n_bits) < n_aux_chains && n_bits < 16)
+    ++n_bits;
+  CHECK_AND_ASSERT_THROW_MES(n_bits <= 16, "Way too many bits required");
+
+  const uint32_t depth = (n_bits - 1) | ((n_aux_chains - 1) << 3) | (nonce << (3 + n_bits));
+  return depth;
+}
+//---------------------------------------------------------------
+bool decode_mm_depth(uint32_t depth, uint32_t &n_aux_chains, uint32_t &nonce)
+{
+  const uint32_t n_bits = 1 + (depth & 7);
+  n_aux_chains = 1 + (depth >> 3 & ((1 << n_bits) - 1));
+  nonce = depth >> (3 + n_bits);
+  return true;
+}
+//---------------------------------------------------------------
+}
diff --git a/src/cryptonote_basic/merge_mining.h b/src/cryptonote_basic/merge_mining.h
new file mode 100644
index 000000000..378438f7c
--- /dev/null
+++ b/src/cryptonote_basic/merge_mining.h
@@ -0,0 +1,40 @@
+// Copyright (c) 2020, 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.
+
+#pragma once
+
+#include <stdint.h>
+#include "crypto/crypto.h"
+
+namespace cryptonote
+{
+  uint32_t get_aux_slot(const crypto::hash &id, uint32_t nonce, uint32_t n_aux_chains);
+  uint32_t get_path_from_aux_slot(uint32_t slot, uint32_t n_aux_chains);
+  uint32_t encode_mm_depth(uint32_t n_aux_chains, uint32_t nonce);
+  bool decode_mm_depth(uint32_t depth, uint32_t &n_aux_chains, uint32_t &nonce);
+}