feat(dns): add Lua scripting for DNS queries

common/geodata/lua.go

@@ -0,0 +1,60 @@
+package geodata
+
+import (
+	lua "github.com/yuin/gopher-lua"
+	luar "layeh.com/gopher-luar"
+)
+
+// RegisterLua makes xray.geodata available to require in an LState.
+// Matchers retain registry handles, so they remain usable after a reload.
+func RegisterLua(L *lua.LState) {
+	L.PreloadModule("xray.geodata", func(L *lua.LState) int {
+		module := L.NewTable()
+
+		module.RawSetString("domainMatcher", L.NewFunction(func(L *lua.LState) int {
+			parsed, err := ParseDomainRules(luaRules(L, 1), Domain_Domain)
+			if err != nil {
+				L.RaiseError("%v", err)
+				return 0
+			}
+			matcher, err := DomainReg.BuildDomainMatcher(parsed)
+			if err != nil {
+				L.RaiseError("%v", err)
+				return 0
+			}
+			L.Push(luar.New(L, matcher))
+			return 1
+		}))
+
+		module.RawSetString("ipMatcher", L.NewFunction(func(L *lua.LState) int {
+			parsed, err := ParseIPRules(luaRules(L, 1))
+			if err != nil {
+				L.RaiseError("%v", err)
+				return 0
+			}
+			matcher, err := IPReg.BuildIPMatcher(parsed)
+			if err != nil {
+				L.RaiseError("%v", err)
+				return 0
+			}
+			L.Push(luar.New(L, matcher))
+			return 1
+		}))
+		L.Push(module)
+		return 1
+	})
+}
+
+func luaRules(L *lua.LState, index int) []string {
+	table := L.CheckTable(index)
+	rules := make([]string, table.Len())
+	for i := range rules {
+		value, ok := table.RawGetInt(i + 1).(lua.LString)
+		if !ok {
+			L.RaiseError("geodata rules must be strings")
+			return nil
+		}
+		rules[i] = string(value)
+	}
+	return rules
+}