evo: prohibit entries with duplicate addresses in ExtNetInfo

MnNetInfo cannot store duplicate entries as it can store only one entry,
so it cannot emit NetInfoStatus::Duplicate.

Author: kwvg

src/evo/deterministicmns.cpp

@@ -910,6 +910,7 @@ static bool CheckService(const ProTx& proTx, TxValidationState& state)
         return true;
     // Shouldn't be possible during self-checks
     case NetInfoStatus::BadInput:
+    case NetInfoStatus::Duplicate:
     case NetInfoStatus::MaxLimit:
         assert(false);
     } // no default case, so the compiler can warn about missing cases

src/evo/netinfo.cpp

@@ -259,13 +259,35 @@ std::string MnNetInfo::ToString() const
     return IsEmpty() ? "MnNetInfo()" : strprintf("MnNetInfo([%s])", m_addr.ToString());
 }
 
+bool ExtNetInfo::HasDuplicates() const
+{
+    std::unordered_set<std::string> known{};
+    for (const NetInfoEntry& entry : m_data) {
+        if (auto [_, inserted] = known.insert(entry.ToStringAddr()); !inserted) {
+            return true;
+        }
+    }
+    ASSERT_IF_DEBUG(known.size() == m_data.size());
+    return false;
+}
+
+bool ExtNetInfo::IsDuplicateCandidate(const NetInfoEntry& candidate) const
+{
+    const std::string& candidate_str{candidate.ToStringAddr()};
+    return std::any_of(m_data.begin(), m_data.end(),
+                       [&candidate_str](const auto& entry) { return candidate_str == entry.ToStringAddr(); });
+}
+
 NetInfoStatus ExtNetInfo::ProcessCandidate(const NetInfoEntry& candidate)
 {
     assert(candidate.IsTriviallyValid());
 
     if (m_data.size() >= MAX_ENTRIES_EXTNETINFO) {
         return NetInfoStatus::MaxLimit;
     }
+    if (IsDuplicateCandidate(candidate)) {
+        return NetInfoStatus::Duplicate;
+    }
     m_data.push_back(candidate);
 
     return NetInfoStatus::Success;
@@ -331,6 +353,9 @@ NetInfoStatus ExtNetInfo::Validate() const
     if (m_version == 0 || m_version > CURRENT_VERSION || m_data.empty()) {
         return NetInfoStatus::Malformed;
     }
+    if (HasDuplicates()) {
+        return NetInfoStatus::Duplicate;
+    }
     for (const auto& entry : m_data) {
         if (!entry.IsTriviallyValid()) {
             // Trivially invalid NetInfoEntry, no point checking against consensus rules

src/evo/netinfo.h

@@ -21,6 +21,7 @@ static constexpr uint8_t MAX_ENTRIES_EXTNETINFO{4};
 enum class NetInfoStatus : uint8_t {
     // Managing entries
     BadInput,
+    Duplicate,
     MaxLimit,
 
     // Validation
@@ -44,6 +45,8 @@ constexpr std::string_view NISToString(const NetInfoStatus code)
         return "invalid port";
     case NetInfoStatus::BadType:
         return "invalid address type";
+    case NetInfoStatus::Duplicate:
+        return "duplicate";
     case NetInfoStatus::NotRoutable:
         return "unroutable address";
     case NetInfoStatus::Malformed:
@@ -228,6 +231,12 @@ class ExtNetInfo final : public NetInfoInterface
     /** Update if serialization or ruleset changed */
     static constexpr uint8_t CURRENT_VERSION{1};
 
+    /** Returns true if there are addr:port duplicates in the object */
+    bool HasDuplicates() const;
+
+    /** Returns true if candidate is an addr:port duplicate in the object */
+    bool IsDuplicateCandidate(const NetInfoEntry& candidate) const;
+
     /** Validate uniqueness requirements and add to object if passed */
     NetInfoStatus ProcessCandidate(const NetInfoEntry& candidate);
 

src/test/evo_netinfo_tests.cpp

@@ -126,6 +126,16 @@ BOOST_FIXTURE_TEST_CASE(extnetinfo_rules_reg, RegTestingSetup)
         BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.5:9998"), NetInfoStatus::MaxLimit);
         ValidateGetEntries(netInfo.GetEntries(), /*expected_size=*/MAX_ENTRIES_EXTNETINFO);
     }
+
+    {
+        // ExtNetInfo does not allow storing duplicates
+        ExtNetInfo netInfo;
+        BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.1:9998"), NetInfoStatus::Success);
+        // Exact duplicates are prohibited
+        BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.1:9998"), NetInfoStatus::Duplicate);
+        // Partial duplicates (same address, different port) are also prohibited
+        BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.1:9997"), NetInfoStatus::Duplicate);
+    }
 }
 
 BOOST_AUTO_TEST_CASE(netinfo_ser)