evo: prohibit overwriting entry in MnNetInfo

Author: kwvg

src/evo/deterministicmns.cpp

@@ -1243,6 +1243,9 @@ static bool CheckService(const ProTx& proTx, TxValidationState& state)
         return state.Invalid(TxValidationResult::TX_BAD_SPECIAL, "bad-protx-netinfo-terrible");
     case NetInfoStatus::Success:
         return true;
+    // Shouldn't be possible during self-checks
+    case NetInfoStatus::MaxLimit:
+        assert(false);
     } // no default case, so the compiler can warn about missing cases
     assert(false);
 }

src/evo/netinfo.cpp

@@ -145,6 +145,9 @@ NetInfoStatus MnNetInfo::ValidateService(const CService& service)
 
 NetInfoStatus MnNetInfo::AddEntry(const std::string& input)
 {
+    if (!IsEmpty()) {
+        return NetInfoStatus::MaxLimit;
+    }
     if (auto service = Lookup(input, /*portDefault=*/Params().GetDefaultPort(), /*fAllowLookup=*/false);
         service.has_value()) {
         const auto ret = ValidateService(service.value());

src/evo/netinfo.h

@@ -13,6 +13,10 @@
 class CService;
 
 enum NetInfoStatus : uint8_t {
+    // Adding entries
+    MaxLimit,
+
+    // Validation
     BadInput,
     BadPort,
     Malformed,
@@ -22,6 +26,8 @@ enum NetInfoStatus : uint8_t {
 constexpr std::string_view NISToString(const NetInfoStatus code)
 {
     switch (code) {
+    case NetInfoStatus::MaxLimit:
+        return "too many entries";
     case NetInfoStatus::BadInput:
         return "invalid address";
     case NetInfoStatus::BadPort:

src/test/evo_netinfo_tests.cpp

@@ -57,6 +57,14 @@ BOOST_AUTO_TEST_CASE(mnnetinfo_rules)
             ValidateGetEntries(netInfo.GetEntries(), /*expected_size=*/1);
         }
     }
+
+    {
+        // MnNetInfo only stores one value, overwriting prohibited
+        MnNetInfo netInfo;
+        BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.1:8888"), NetInfoStatus::Success);
+        BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.2:8888"), NetInfoStatus::MaxLimit);
+        ValidateGetEntries(netInfo.GetEntries(), /*expected_size=*/1);
+    }
 }
 
 bool CheckIfSerSame(const CService& lhs, const MnNetInfo& rhs)
@@ -81,6 +89,7 @@ BOOST_AUTO_TEST_CASE(cservice_compatible)
 
     // Valid IPv4 address, default P2P port implied
     service = LookupNumeric("1.1.1.1", Params().GetDefaultPort());
+    netInfo.Clear();
     BOOST_CHECK_EQUAL(netInfo.AddEntry("1.1.1.1"), NetInfoStatus::Success);
     BOOST_CHECK(CheckIfSerSame(service, netInfo));