MOVEONLY: Expose BanMapToJson / BanMapFromJson

CSubNet serialization code that was removed in
fa4e6afdae7b82df638b60edf37ac36d57a8cb4f was needed by multiprocess code
to share ban map between gui and node processes.

Rather than adding it back, use suggestion from MarcoFalke
<falke.marco@gmail.com>
https://github.com/bitcoin/bitcoin/pull/10102#discussion_r690922929 to
use JSON serialization. This requires making BanMapToJson /
BanMapFromJson functions public.

5 files changed, 112 insertions, 85 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index a8d6591e98..6f8245de8a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -548,6 +548,7 @@ libbitcoin_common_a_SOURCES = \
   key.cpp \
   key_io.cpp \
   merkleblock.cpp \
+  net_types.cpp \
   netaddress.cpp \
   netbase.cpp \
   net_permissions.cpp \
diff --git a/src/addrdb.cpp b/src/addrdb.cpp
index a5383be7cf..345dbdfb16 100644
--- a/src/addrdb.cpp
+++ b/src/addrdb.cpp
@@ -19,64 +19,7 @@
 #include <util/settings.h>
 #include <util/system.h>
 
-CBanEntry::CBanEntry(const UniValue& json)
-    : nVersion(json["version"].get_int()), nCreateTime(json["ban_created"].get_int64()),
-      nBanUntil(json["banned_until"].get_int64())
-{
-}
-
-UniValue CBanEntry::ToJson() const
-{
-    UniValue json(UniValue::VOBJ);
-    json.pushKV("version", nVersion);
-    json.pushKV("ban_created", nCreateTime);
-    json.pushKV("banned_until", nBanUntil);
-    return json;
-}
-
 namespace {
-
-static const char* BANMAN_JSON_ADDR_KEY = "address";
-
-/**
- * Convert a `banmap_t` object to a JSON array.
- * @param[in] bans Bans list to convert.
- * @return a JSON array, similar to the one returned by the `listbanned` RPC. Suitable for
- * passing to `BanMapFromJson()`.
- */
-UniValue BanMapToJson(const banmap_t& bans)
-{
-    UniValue bans_json(UniValue::VARR);
-    for (const auto& it : bans) {
-        const auto& address = it.first;
-        const auto& ban_entry = it.second;
-        UniValue j = ban_entry.ToJson();
-        j.pushKV(BANMAN_JSON_ADDR_KEY, address.ToString());
-        bans_json.push_back(j);
-    }
-    return bans_json;
-}
-
-/**
- * Convert a JSON array to a `banmap_t` object.
- * @param[in] bans_json JSON to convert, must be as returned by `BanMapToJson()`.
- * @param[out] bans Bans list to create from the JSON.
- * @throws std::runtime_error if the JSON does not have the expected fields or they contain
- * unparsable values.
- */
-void BanMapFromJson(const UniValue& bans_json, banmap_t& bans)
-{
-    for (const auto& ban_entry_json : bans_json.getValues()) {
-        CSubNet subnet;
-        const auto& subnet_str = ban_entry_json[BANMAN_JSON_ADDR_KEY].get_str();
-        if (!LookupSubNet(subnet_str, subnet)) {
-            throw std::runtime_error(
-                strprintf("Cannot parse banned address or subnet: %s", subnet_str));
-        }
-        bans.insert_or_assign(subnet, CBanEntry{ban_entry_json});
-    }
-}
-
 template <typename Stream, typename Data>
 bool SerializeDB(Stream& stream, const Data& data)
 {
diff --git a/src/addrdb.h b/src/addrdb.h
index 26400ee0b6..26b1c5880f 100644
--- a/src/addrdb.h
+++ b/src/addrdb.h
@@ -16,33 +16,6 @@ class CAddress;
 class CAddrMan;
 class CDataStream;
 
-class CBanEntry
-{
-public:
-    static constexpr int CURRENT_VERSION{1};
-    int nVersion{CBanEntry::CURRENT_VERSION};
-    int64_t nCreateTime{0};
-    int64_t nBanUntil{0};
-
-    CBanEntry() {}
-
-    explicit CBanEntry(int64_t nCreateTimeIn)
-        : nCreateTime{nCreateTimeIn} {}
-
-    /**
-     * Create a ban entry from JSON.
-     * @param[in] json A JSON representation of a ban entry, as created by `ToJson()`.
-     * @throw std::runtime_error if the JSON does not have the expected fields.
-     */
-    explicit CBanEntry(const UniValue& json);
-
-    /**
-     * Generate a JSON representation of this ban entry.
-     * @return JSON suitable for passing to the `CBanEntry(const UniValue&)` constructor.
-     */
-    UniValue ToJson() const;
-};
-
 /** Access to the (IP) address database (peers.dat) */
 class CAddrDB
 {
diff --git a/src/net_types.cpp b/src/net_types.cpp
new file mode 100644
index 0000000000..c8f57fe6c6
--- /dev/null
+++ b/src/net_types.cpp
@@ -0,0 +1,65 @@
+// Copyright (c) 2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <net_types.h>
+
+#include <netaddress.h>
+#include <netbase.h>
+#include <univalue.h>
+
+CBanEntry::CBanEntry(const UniValue& json)
+    : nVersion(json["version"].get_int()), nCreateTime(json["ban_created"].get_int64()),
+      nBanUntil(json["banned_until"].get_int64())
+{
+}
+
+UniValue CBanEntry::ToJson() const
+{
+    UniValue json(UniValue::VOBJ);
+    json.pushKV("version", nVersion);
+    json.pushKV("ban_created", nCreateTime);
+    json.pushKV("banned_until", nBanUntil);
+    return json;
+}
+
+static const char* BANMAN_JSON_ADDR_KEY = "address";
+
+/**
+ * Convert a `banmap_t` object to a JSON array.
+ * @param[in] bans Bans list to convert.
+ * @return a JSON array, similar to the one returned by the `listbanned` RPC. Suitable for
+ * passing to `BanMapFromJson()`.
+ */
+UniValue BanMapToJson(const banmap_t& bans)
+{
+    UniValue bans_json(UniValue::VARR);
+    for (const auto& it : bans) {
+        const auto& address = it.first;
+        const auto& ban_entry = it.second;
+        UniValue j = ban_entry.ToJson();
+        j.pushKV(BANMAN_JSON_ADDR_KEY, address.ToString());
+        bans_json.push_back(j);
+    }
+    return bans_json;
+}
+
+/**
+ * Convert a JSON array to a `banmap_t` object.
+ * @param[in] bans_json JSON to convert, must be as returned by `BanMapToJson()`.
+ * @param[out] bans Bans list to create from the JSON.
+ * @throws std::runtime_error if the JSON does not have the expected fields or they contain
+ * unparsable values.
+ */
+void BanMapFromJson(const UniValue& bans_json, banmap_t& bans)
+{
+    for (const auto& ban_entry_json : bans_json.getValues()) {
+        CSubNet subnet;
+        const auto& subnet_str = ban_entry_json[BANMAN_JSON_ADDR_KEY].get_str();
+        if (!LookupSubNet(subnet_str, subnet)) {
+            throw std::runtime_error(
+                strprintf("Cannot parse banned address or subnet: %s", subnet_str));
+        }
+        bans.insert_or_assign(subnet, CBanEntry{ban_entry_json});
+    }
+}
diff --git a/src/net_types.h b/src/net_types.h
index d55a8cde6c..ffdc24c772 100644
--- a/src/net_types.h
+++ b/src/net_types.h
@@ -5,11 +5,56 @@
 #ifndef BITCOIN_NET_TYPES_H
 #define BITCOIN_NET_TYPES_H
 
+#include <cstdint>
 #include <map>
 
-class CBanEntry;
 class CSubNet;
+class UniValue;
+
+class CBanEntry
+{
+public:
+    static constexpr int CURRENT_VERSION{1};
+    int nVersion{CBanEntry::CURRENT_VERSION};
+    int64_t nCreateTime{0};
+    int64_t nBanUntil{0};
+
+    CBanEntry() {}
+
+    explicit CBanEntry(int64_t nCreateTimeIn)
+        : nCreateTime{nCreateTimeIn} {}
+
+    /**
+     * Create a ban entry from JSON.
+     * @param[in] json A JSON representation of a ban entry, as created by `ToJson()`.
+     * @throw std::runtime_error if the JSON does not have the expected fields.
+     */
+    explicit CBanEntry(const UniValue& json);
+
+    /**
+     * Generate a JSON representation of this ban entry.
+     * @return JSON suitable for passing to the `CBanEntry(const UniValue&)` constructor.
+     */
+    UniValue ToJson() const;
+};
 
 using banmap_t = std::map<CSubNet, CBanEntry>;
 
+/**
+ * Convert a `banmap_t` object to a JSON array.
+ * @param[in] bans Bans list to convert.
+ * @return a JSON array, similar to the one returned by the `listbanned` RPC. Suitable for
+ * passing to `BanMapFromJson()`.
+ */
+UniValue BanMapToJson(const banmap_t& bans);
+
+/**
+ * Convert a JSON array to a `banmap_t` object.
+ * @param[in] bans_json JSON to convert, must be as returned by `BanMapToJson()`.
+ * @param[out] bans Bans list to create from the JSON.
+ * @throws std::runtime_error if the JSON does not have the expected fields or they contain
+ * unparsable values.
+ */
+void BanMapFromJson(const UniValue& bans_json, banmap_t& bans);
+
 #endif // BITCOIN_NET_TYPES_H