Revert "A bit of DB model cleanup (#5016)"

This reverts commit 8a3cee9a10.

Content.Server/Database/ServerDbSqlite.cs

@@ -104,7 +104,7 @@ namespace Content.Server.Database
             NetUserId? userId,
             ImmutableArray<byte>? hwId)
         {
-            if (address != null && ban.Address is not null && IPAddressExt.IsInSubnet(address, ban.Address.Value))
+            if (address != null && ban.Address != null && IPAddressExt.IsInSubnet(address, ban.Address))
             {
                 return true;
             }
@@ -126,9 +126,15 @@ namespace Content.Server.Database
         {
             await using var db = await GetDbImpl();
 
+            string? addrStr = null;
+            if (serverBan.Address is { } addr)
+            {
+                addrStr = $"{addr.address}/{addr.cidrMask}";
+            }
+
             db.SqliteDbContext.Ban.Add(new SqliteServerBan
             {
-                Address = serverBan.Address,
+                Address = addrStr,
                 Reason = serverBan.Reason,
                 BanningAdmin = serverBan.BanningAdmin?.UserId,
                 HWId = serverBan.HWId?.ToArray(),
@@ -239,12 +245,20 @@ namespace Content.Server.Database
                 aUid = new NetUserId(aGuid);
             }
 
+            (IPAddress, int)? addrTuple = null;
+            if (ban.Address != null)
+            {
+                var idx = ban.Address.IndexOf('/', StringComparison.Ordinal);
+                addrTuple = (IPAddress.Parse(ban.Address.AsSpan(0, idx)),
+                    int.Parse(ban.Address.AsSpan(idx + 1), provider: CultureInfo.InvariantCulture));
+            }
+
             var unban = ConvertUnban(ban.Unban);
 
             return new ServerBanDef(
                 ban.Id,
                 uid,
-                ban.Address,
+                addrTuple,
                 ban.HWId == null ? null : ImmutableArray.Create(ban.HWId),
                 ban.BanTime,
                 ban.ExpirationTime,