refactor: Use span instead of vector for data in util/asmap

This prevents holding the asmap data in memory twice.

The version hash changes due to spans being serialized without their size-prefix (unlike vectors).

src/bench/addrman.cpp

@@ -24,7 +24,7 @@
 static constexpr size_t NUM_SOURCES = 64;
 static constexpr size_t NUM_ADDRESSES_PER_SOURCE = 256;
 
-static NetGroupManager EMPTY_NETGROUPMAN{{}};
+static auto EMPTY_NETGROUPMAN{NetGroupManager::NoAsmap()};
 static constexpr uint32_t ADDRMAN_CONSISTENCY_CHECK_RATIO{0};
 
 static std::vector<CAddress> g_sources;

src/init.cpp

@@ -1560,9 +1560,9 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     ApplyArgsManOptions(args, peerman_opts);
 
     {
-
+        // Read asmap file if configured and initialize
-        // Read asmap file if configured
+        // Netgroupman with or without it
-        std::vector<std::byte> asmap;
+        assert(!node.netgroupman);
         if (args.IsArgSet("-asmap") && !args.IsArgNegated("-asmap")) {
             fs::path asmap_path = args.GetPathArg("-asmap");
             if (asmap_path.empty()) {
@@ -1576,21 +1576,19 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                 InitError(strprintf(_("Could not find asmap file %s"), fs::quoted(fs::PathToString(asmap_path))));
                 return false;
             }
-            asmap = DecodeAsmap(asmap_path);
+            std::vector<std::byte> asmap{DecodeAsmap(asmap_path)};
             if (asmap.size() == 0) {
                 InitError(strprintf(_("Could not parse asmap file %s"), fs::quoted(fs::PathToString(asmap_path))));
                 return false;
             }
-            const uint256 asmap_version = AsmapVersion(asmap);;
+            const uint256 asmap_version = AsmapVersion(asmap);
+            node.netgroupman = std::make_unique<NetGroupManager>(NetGroupManager::WithLoadedAsmap(std::move(asmap)));
             LogInfo("Using asmap version %s for IP bucketing", asmap_version.ToString());
         } else {
+            node.netgroupman = std::make_unique<NetGroupManager>(NetGroupManager::NoAsmap());
             LogInfo("Using /16 prefix for IP bucketing");
         }
 
-        // Initialize netgroup manager
-        assert(!node.netgroupman);
-        node.netgroupman = std::make_unique<NetGroupManager>(std::move(asmap));
-
         // Initialize addrman
         assert(!node.addrman);
         uiInterface.InitMessage(_("Loading P2P addresses…"));

src/netgroup.cpp

@@ -6,6 +6,7 @@
 
 #include <hash.h>
 #include <logging.h>
+#include <uint256.h>
 #include <util/asmap.h>
 
 #include <cstddef>

src/netgroup.h

@@ -16,9 +16,22 @@
  */
 class NetGroupManager {
 public:
-    explicit NetGroupManager(std::vector<std::byte>&& asmap)
+    NetGroupManager(const NetGroupManager&) = delete;
-        : m_asmap{std::move(asmap)}
+    NetGroupManager(NetGroupManager&&) = default;
-    {}
+    NetGroupManager& operator=(const NetGroupManager&) = delete;
+    NetGroupManager& operator=(NetGroupManager&&) = delete;
+
+    static NetGroupManager WithEmbeddedAsmap(std::span<const std::byte> asmap) {
+        return NetGroupManager(asmap, {});
+    }
+
+    static NetGroupManager WithLoadedAsmap(std::vector<std::byte>&& asmap) {
+        return NetGroupManager(std::span{asmap}, std::move(asmap));
+    }
+
+    static NetGroupManager NoAsmap() {
+        return NetGroupManager({}, {});
+    }
 
     /** Get the asmap version, a checksum identifying the asmap being used. */
     uint256 GetAsmapVersion() const;
@@ -53,7 +66,10 @@ public:
     bool UsingASMap() const;
 
 private:
-    /** Compressed IP->ASN mapping, loaded from a file when a node starts.
+    /** Compressed IP->ASN mapping.
+     *
+     * Data may be loaded from a file when a node starts or embedded in the
+     * binary.
      *
      * This mapping is then used for bucketing nodes in Addrman and for
      * ensuring we connect to a diverse set of peers in Connman. The map is
@@ -70,8 +86,19 @@ private:
      * re-bucketed.
      *
      * This is initialized in the constructor, const, and therefore is
-     * thread-safe. */
+     * thread-safe. m_asmap can either point to m_loaded_asmap which holds
-    const std::vector<std::byte> m_asmap;
+     * data loaded from an external file at runtime or it can point to embedded
+     * asmap data.
+     */
+    const std::span<const std::byte> m_asmap;
+    std::vector<std::byte> m_loaded_asmap;
+
+    explicit NetGroupManager(std::span<const std::byte> embedded_asmap, std::vector<std::byte>&& loaded_asmap)
+        : m_asmap{embedded_asmap},
+          m_loaded_asmap{std::move(loaded_asmap)}
+    {
+        assert(m_loaded_asmap.empty() || m_asmap.data() == m_loaded_asmap.data());
+    }
 };
 
 #endif // BITCOIN_NETGROUP_H

src/test/addrman_tests.cpp

@@ -24,7 +24,7 @@ using namespace std::literals;
 using node::NodeContext;
 using util::ToString;
 
-static NetGroupManager EMPTY_NETGROUPMAN{{}};
+static auto EMPTY_NETGROUPMAN{NetGroupManager::NoAsmap()};
 static const bool DETERMINISTIC{true};
 
 static int32_t GetCheckRatio(const NodeContext& node_ctx)
@@ -584,8 +584,7 @@ BOOST_AUTO_TEST_CASE(caddrinfo_get_new_bucket_legacy)
 // 101.8.0.0/16 AS8
 BOOST_AUTO_TEST_CASE(caddrinfo_get_tried_bucket)
 {
-    std::vector<std::byte> asmap(test::data::asmap.begin(), test::data::asmap.end());
+    auto ngm_asmap{NetGroupManager::WithEmbeddedAsmap(test::data::asmap)};
-    NetGroupManager ngm_asmap{std::move(asmap)};
 
     CAddress addr1 = CAddress(ResolveService("250.1.1.1", 8333), NODE_NONE);
     CAddress addr2 = CAddress(ResolveService("250.1.1.1", 9999), NODE_NONE);
@@ -638,8 +637,7 @@ BOOST_AUTO_TEST_CASE(caddrinfo_get_tried_bucket)
 
 BOOST_AUTO_TEST_CASE(caddrinfo_get_new_bucket)
 {
-    std::vector<std::byte> asmap(test::data::asmap.begin(), test::data::asmap.end());
+    auto ngm_asmap{NetGroupManager::WithEmbeddedAsmap(test::data::asmap)};
-    NetGroupManager ngm_asmap{std::move(asmap)};
 
     CAddress addr1 = CAddress(ResolveService("250.1.2.1", 8333), NODE_NONE);
     CAddress addr2 = CAddress(ResolveService("250.1.2.1", 9999), NODE_NONE);
@@ -716,8 +714,7 @@ BOOST_AUTO_TEST_CASE(caddrinfo_get_new_bucket)
 
 BOOST_AUTO_TEST_CASE(addrman_serialization)
 {
-    std::vector<std::byte> asmap1(test::data::asmap.begin(), test::data::asmap.end());
+    auto netgroupman{NetGroupManager::WithEmbeddedAsmap(test::data::asmap)};
-    NetGroupManager netgroupman{std::move(asmap1)};
 
     const auto ratio = GetCheckRatio(m_node);
     auto addrman_asmap1 = std::make_unique<AddrMan>(netgroupman, DETERMINISTIC, ratio);

src/test/fuzz/asmap.cpp

@@ -29,7 +29,7 @@ FUZZ_TARGET(asmap)
     if (buffer.size() < size_t(1 + asmap_size + addr_size)) return;
     std::vector<std::byte> asmap = ipv6 ? IPV6_PREFIX_ASMAP : IPV4_PREFIX_ASMAP;
     std::ranges::copy(std::as_bytes(buffer.subspan(1, asmap_size)), std::back_inserter(asmap));
-    if (!SanityCheckASMap(asmap, 128)) return;
+    if (!CheckStandardAsmap(asmap)) return;
 
     const uint8_t* addr_data = buffer.data() + 1 + asmap_size;
     CNetAddr net_addr;
@@ -42,6 +42,6 @@ FUZZ_TARGET(asmap)
         memcpy(&ipv4, addr_data, addr_size);
         net_addr.SetIP(CNetAddr{ipv4});
     }
-    NetGroupManager netgroupman{std::move(asmap)};
+    auto netgroupman{NetGroupManager::WithEmbeddedAsmap(asmap)};
     (void)netgroupman.GetMappedAS(net_addr);
 }

src/test/fuzz/p2p_handshake.cpp

@@ -48,7 +48,7 @@ FUZZ_TARGET(p2p_handshake, .init = ::initialize)
     chainman.ResetIbd();
 
     node::Warnings warnings{};
-    NetGroupManager netgroupman{{}};
+    auto netgroupman{NetGroupManager::NoAsmap()};
     AddrMan addrman{netgroupman, /*deterministic=*/true, /*consistency_check_ratio=*/0};
     auto peerman = PeerManager::make(connman, addrman,
                                      /*banman=*/nullptr, chainman,

src/test/fuzz/util/net.h

@@ -236,8 +236,10 @@ public:
 [[nodiscard]] inline NetGroupManager ConsumeNetGroupManager(FuzzedDataProvider& fuzzed_data_provider) noexcept
 {
     std::vector<std::byte> asmap{ConsumeRandomLengthByteVector<std::byte>(fuzzed_data_provider)};
-    if (!SanityCheckASMap(asmap, 128)) asmap.clear();
+    if (!CheckStandardAsmap(asmap)) {
-    return NetGroupManager(std::move(asmap));
+        return NetGroupManager::NoAsmap();
+    }
+    return NetGroupManager::WithLoadedAsmap(std::move(asmap));
 }
 
 inline CSubNet ConsumeSubNet(FuzzedDataProvider& fuzzed_data_provider) noexcept

src/test/netbase_tests.cpp

@@ -325,7 +325,7 @@ BOOST_AUTO_TEST_CASE(subnet_test)
 
 BOOST_AUTO_TEST_CASE(netbase_getgroup)
 {
-    NetGroupManager netgroupman{{}}; // use /16
+    auto netgroupman{NetGroupManager::NoAsmap()}; // use /16
     BOOST_CHECK(netgroupman.GetGroup(ResolveIP("127.0.0.1")) == std::vector<unsigned char>({0})); // Local -> !Routable()
     BOOST_CHECK(netgroupman.GetGroup(ResolveIP("257.0.0.1")) == std::vector<unsigned char>({0})); // !Valid -> !Routable()
     BOOST_CHECK(netgroupman.GetGroup(ResolveIP("10.0.0.1")) == std::vector<unsigned char>({0})); // RFC1918 -> !Routable()
@@ -631,7 +631,7 @@ BOOST_AUTO_TEST_CASE(asmap_test_vectors)
         "63dc33d28f757a4a5e15d6a08"_hex};
 
     // Construct NetGroupManager with this data.
-    NetGroupManager netgroup{std::vector(ASMAP_DATA.begin(), ASMAP_DATA.end())};
+    auto netgroup{NetGroupManager::WithEmbeddedAsmap(ASMAP_DATA)};
     BOOST_CHECK(netgroup.UsingASMap());
 
     // Check some randomly-generated IPv6 addresses in it (biased towards the very beginning and

src/test/util/setup_common.cpp

@@ -344,7 +344,7 @@ TestingSetup::TestingSetup(
 
     if (!opts.setup_net) return;
 
-    m_node.netgroupman = std::make_unique<NetGroupManager>(/*asmap=*/std::vector<std::byte>{});
+    m_node.netgroupman = std::make_unique<NetGroupManager>(NetGroupManager::NoAsmap());
     m_node.addrman = std::make_unique<AddrMan>(*m_node.netgroupman,
                                                /*deterministic=*/false,
                                                m_node.args->GetIntArg("-checkaddrman", 0));

src/util/asmap.cpp

@@ -17,6 +17,7 @@
 #include <cassert>
 #include <cstddef>
 #include <cstdio>
+#include <span>
 #include <utility>
 #include <vector>
 
@@ -38,7 +39,7 @@ inline bool ConsumeBitBE(uint8_t& bitpos, std::span<const std::byte> bytes) noex
     return bit;
 }
 
-uint32_t DecodeBits(size_t& bitpos, const std::vector<std::byte>& data, uint8_t minval, const std::vector<uint8_t>& bit_sizes)
+uint32_t DecodeBits(size_t& bitpos, const std::span<const std::byte> data, uint8_t minval, const std::span<const uint8_t> bit_sizes)
 {
     uint32_t val = minval;
     bool bit;
@@ -71,35 +72,33 @@ enum class Instruction : uint32_t
     DEFAULT = 3,
 };
 
-const std::vector<uint8_t> TYPE_BIT_SIZES{0, 0, 1};
+constexpr uint8_t TYPE_BIT_SIZES[]{0, 0, 1};
-Instruction DecodeType(size_t& bitpos, const std::vector<std::byte>& data)
+Instruction DecodeType(size_t& bitpos, const std::span<const std::byte> data)
 {
     return Instruction(DecodeBits(bitpos, data, 0, TYPE_BIT_SIZES));
 }
 
-const std::vector<uint8_t> ASN_BIT_SIZES{15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
+constexpr uint8_t ASN_BIT_SIZES[]{15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
-uint32_t DecodeASN(size_t& bitpos, const std::vector<std::byte>& data)
+uint32_t DecodeASN(size_t& bitpos, const std::span<const std::byte> data)
 {
     return DecodeBits(bitpos, data, 1, ASN_BIT_SIZES);
 }
 
-
+constexpr uint8_t MATCH_BIT_SIZES[]{1, 2, 3, 4, 5, 6, 7, 8};
-const std::vector<uint8_t> MATCH_BIT_SIZES{1, 2, 3, 4, 5, 6, 7, 8};
+uint32_t DecodeMatch(size_t& bitpos, const std::span<const std::byte> data)
-uint32_t DecodeMatch(size_t& bitpos, const std::vector<std::byte>& data)
 {
     return DecodeBits(bitpos, data, 2, MATCH_BIT_SIZES);
 }
 
-
+constexpr uint8_t JUMP_BIT_SIZES[]{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};
-const std::vector<uint8_t> JUMP_BIT_SIZES{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};
+uint32_t DecodeJump(size_t& bitpos, const std::span<const std::byte> data)
-uint32_t DecodeJump(size_t& bitpos, const std::vector<std::byte>& data)
 {
     return DecodeBits(bitpos, data, 17, JUMP_BIT_SIZES);
 }
 
 }
 
-uint32_t Interpret(const std::vector<std::byte>& asmap, const std::vector<std::byte>& ip)
+uint32_t Interpret(const std::span<const std::byte> asmap, const std::span<const std::byte> ip)
 {
     size_t pos{0};
     const size_t endpos{asmap.size() * 8};
@@ -143,7 +142,7 @@ uint32_t Interpret(const std::vector<std::byte>& asmap, const std::vector<std::b
     return 0; // 0 is not a valid ASN
 }
 
-bool SanityCheckASMap(const std::vector<std::byte>& asmap, int bits)
+bool SanityCheckASMap(const std::span<const std::byte> asmap, int bits)
 {
     size_t pos{0};
     const size_t endpos{asmap.size() * 8};
@@ -204,6 +203,15 @@ bool SanityCheckASMap(const std::vector<std::byte>& asmap, int bits)
     return false; // Reached EOF without RETURN instruction
 }
 
+bool CheckStandardAsmap(const std::span<const std::byte> data)
+{
+    if (!SanityCheckASMap(data, 128)) {
+        LogWarning("Sanity check of asmap data failed\n");
+        return false;
+    }
+    return true;
+}
+
 std::vector<std::byte> DecodeAsmap(fs::path path)
 {
     FILE *filestr = fsbridge::fopen(path, "rb");
@@ -218,7 +226,7 @@ std::vector<std::byte> DecodeAsmap(fs::path path)
     std::vector<std::byte> buffer(length);
     file.read(buffer);
 
-    if (!SanityCheckASMap(buffer, 128)) {
+    if (!CheckStandardAsmap(buffer)) {
         LogWarning("Sanity check of asmap file %s failed", fs::quoted(fs::PathToString(path)));
         return {};
     }
@@ -226,7 +234,7 @@ std::vector<std::byte> DecodeAsmap(fs::path path)
     return buffer;
 }
 
-uint256 AsmapVersion(const std::vector<std::byte>& data)
+uint256 AsmapVersion(const std::span<const std::byte> data)
 {
     if (data.empty()) return {};
 

src/util/asmap.h

@@ -10,15 +10,18 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <span>
 #include <vector>
 
-uint32_t Interpret(const std::vector<std::byte>& asmap, const std::vector<std::byte>& ip);
+uint32_t Interpret(std::span<const std::byte> asmap, std::span<const std::byte> ip);
 
-bool SanityCheckASMap(const std::vector<std::byte>& asmap, int bits);
+bool SanityCheckASMap(std::span<const std::byte> asmap, int bits);
+/** Check standard asmap data (128 bits for IPv6) */
+bool CheckStandardAsmap(std::span<const std::byte> data);
 
-/** Read asmap from provided binary file */
+/** Read and check asmap from provided binary file */
 std::vector<std::byte> DecodeAsmap(fs::path path);
 /** Calculate the asmap version, a checksum identifying the asmap being used. */
-uint256 AsmapVersion(const std::vector<std::byte>& data);
+uint256 AsmapVersion(std::span<const std::byte> data);
 
 #endif // BITCOIN_UTIL_ASMAP_H

test/functional/feature_asmap.py

@@ -18,7 +18,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
 ASMAP = 'src/test/data/asmap.raw' # path to unit test skeleton asmap
-VERSION = '6dfbc157b8a97b6e9fc7fc08d4e43d30247bbf62055eaa1098f46db9885855e3'
+VERSION = 'bafc9da308f45179443bd1d22325400ac9104f741522d003e3fac86700f68895'
 
 def expected_messages(filename):
     return [f'Opened asmap file "{filename}" (59 bytes) from disk',