Adds Sing-box legacy DNS config support

v2rayN/ServiceLib/Models/SingboxConfig.cs

@@ -227,6 +227,12 @@ public class Server4Sbox
     public string? server { get; set; }
     public string? server_resolver { get; set; }
     [JsonPropertyName("interface")] public string? Interface { get; set; }
+    // Deprecated
+    public string? address { get; set; }
+    public string? address_resolver { get; set; }
+    public string? address_strategy { get; set; }
+    public string? strategy { get; set; }
+    // Deprecated End
 }
 
 public class Experimental4Sbox

v2rayN/ServiceLib/Sample/dns_singbox_normal

@@ -4,14 +4,12 @@
       "tag": "remote",
       "type": "tcp",
       "server": "8.8.8.8",
-      "strategy": "prefer_ipv4",
       "detour": "proxy"
     },
     {
       "tag": "local",
       "type": "udp",
-      "server": "223.5.5.5",
+      "server": "223.5.5.5"
-      "strategy": "prefer_ipv4"
     }
   ],
   "rules": [

v2rayN/ServiceLib/Sample/tun_singbox_dns

@@ -4,14 +4,12 @@
       "tag": "remote",
       "type": "tcp",
       "server": "8.8.8.8",
-      "strategy": "prefer_ipv4",
       "detour": "proxy"
     },
     {
       "tag": "local",
       "type": "udp",
-      "server": "223.5.5.5",
+      "server": "223.5.5.5"
-      "strategy": "prefer_ipv4"
     }
   ],
   "rules": [

v2rayN/ServiceLib/Services/CoreConfig/CoreConfigSingboxService.cs

@@ -1427,8 +1427,15 @@ public class CoreConfigSingboxService
             }
             singboxConfig.dns = dns4Sbox;
 
+            if (dns4Sbox.servers != null && dns4Sbox.servers.Count > 0 && dns4Sbox.servers.First().address.IsNullOrEmpty())
+            {
                 await GenDnsDomains(node, singboxConfig, item);
             }
+            else
+            {
+                await GenDnsDomainsLegacy(node, singboxConfig, item);
+            }
+        }
         catch (Exception ex)
         {
             Logging.SaveLog(_tag, ex);
@@ -1525,6 +1532,59 @@ public class CoreConfigSingboxService
         return await Task.FromResult(0);
     }
 
+    private async Task<int> GenDnsDomainsLegacy(ProfileItem? node, SingboxConfig singboxConfig, DNSItem? dNSItem)
+    {
+        var dns4Sbox = singboxConfig.dns ?? new();
+        dns4Sbox.servers ??= [];
+        dns4Sbox.rules ??= [];
+
+        var tag = "local_local";
+        dns4Sbox.servers.Add(new()
+        {
+            tag = tag,
+            address = string.IsNullOrEmpty(dNSItem?.DomainDNSAddress) ? Global.SingboxDomainDNSAddress.FirstOrDefault() : dNSItem?.DomainDNSAddress,
+            detour = Global.DirectTag,
+            strategy = string.IsNullOrEmpty(dNSItem?.DomainStrategy4Freedom) ? null : dNSItem?.DomainStrategy4Freedom,
+        });
+        dns4Sbox.rules.Insert(0, new()
+        {
+            server = tag,
+            clash_mode = ERuleMode.Direct.ToString()
+        });
+        dns4Sbox.rules.Insert(0, new()
+        {
+            server = dns4Sbox.servers.Where(t => t.detour == Global.ProxyTag).Select(t => t.tag).FirstOrDefault() ?? "remote",
+            clash_mode = ERuleMode.Global.ToString()
+        });
+
+        var lstDomain = singboxConfig.outbounds
+                       .Where(t => t.server.IsNotEmpty() && Utils.IsDomain(t.server))
+                       .Select(t => t.server)
+                       .Distinct()
+                       .ToList();
+        if (lstDomain != null && lstDomain.Count > 0)
+        {
+            dns4Sbox.rules.Insert(0, new()
+            {
+                server = tag,
+                domain = lstDomain
+            });
+        }
+
+        //Tun2SocksAddress
+        if (_config.TunModeItem.EnableTun && node?.ConfigType == EConfigType.SOCKS && Utils.IsDomain(node?.Sni))
+        {
+            dns4Sbox.rules.Insert(0, new()
+            {
+                server = tag,
+                domain = [node?.Sni]
+            });
+        }
+
+        singboxConfig.dns = dns4Sbox;
+        return await Task.FromResult(0);
+    }
+
     private async Task<int> GenExperimental(SingboxConfig singboxConfig)
     {
         //if (_config.guiItem.enableStatistics)