create dns package

dns/resolver.go

@@ -0,0 +1,30 @@
+// Copyright 2023 Jigsaw Operations LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dns
+
+/*
+	A resolver is a function that resolves a hostname to a list of IP addresses.
+
+	TODO: provide factory methods to create a Resolver. For example:
+
+	```go
+		manualDns := makeManualResolver(
+			map[string][]string{ "example.com": []string{"255.255.255.255:80" }
+		})	
+	
+		dialer := &shadowsocks.NewStreamDialer(endpoint, key, manualDns)
+	````
+*/
+type Resolver func(host string) ([]string, error)