CustomDNS: parameter "filterUnmappedTypes" to allow/disable forwardin…

…g to the upstream resolver (#467)

config/config.go

@@ -317,9 +317,10 @@ type RewriteConfig struct {
 
 // CustomDNSConfig custom DNS configuration
 type CustomDNSConfig struct {
-	RewriteConfig `yaml:",inline"`
-	CustomTTL     Duration         `yaml:"customTTL" default:"1h"`
-	Mapping       CustomDNSMapping `yaml:"mapping"`
+	RewriteConfig       `yaml:",inline"`
+	CustomTTL           Duration         `yaml:"customTTL" default:"1h"`
+	Mapping             CustomDNSMapping `yaml:"mapping"`
+	FilterUnmappedTypes bool             `yaml:"filterUnmappedTypes" default:"true"`
 }
 
 // CustomDNSMapping mapping for the custom DNS configuration

docs/config.yml

@@ -23,6 +23,9 @@ upstreamTimeout: 2s
 # example: query "printer.lan" or "my.printer.lan" will return 192.168.178.3
 customDNS:
   customTTL: 1h
+  # optional: if true (default), return empty result for unmapped query types (for example TXT, MX or AAAA if only IPv4 address is defined).
+  # if false, queries with unmapped types will be forwarded to the upstream resolver
+  filterUnmappedTypes: true
   # optional: replace domain in the query with other domain before resolver lookup in the mapping
   rewrite:
     example.com: printer.lan

docs/configuration.md

@@ -115,17 +115,19 @@ You can define your own domain name to IP mappings. For example, you can use a u
 or define a domain name for your local device on order to use the HTTPS certificate. Multiple IP addresses for one
 domain must be separated by a comma.
 
-| Parameter | Type                                    | Mandatory | Default value |
-|-----------|-----------------------------------------|-----------|---------------|
-| customTTL | duration (no unit is minutes)           | no        | 1h            |
-| rewrite   | string: string (domain: domain)         | no        |               |
-| mapping   | string: string (hostname: address list) | no        |               |
+| Parameter | Type                                                | Mandatory | Default value |
+|-----------------------|-----------------------------------------|-----------|---------------|
+| customTTL             | duration (no unit is minutes)           | no        | 1h            |
+| rewrite               | string: string (domain: domain)         | no        |               |
+| mapping               | string: string (hostname: address list) | no        |               |
+| filterUnmappedTypes   | boolean                                 | no        | true          |
 
 !!! example
 
     ```yaml
     customDNS:
         customTTL: 1h
+        filterUnmappedTypes: true
         rewrite:
             home: lan
             replace-me.com: with-this.com
@@ -141,6 +143,10 @@ With the optional parameter `rewrite` you can replace domain part of the query w
 resolver lookup is performed.  
 The query "printer.home" will be rewritten to "printer.lan" and return 192.168.178.3.
 
+With parameter `filterUnmappedTypes = true` (default), blocky will filter all queries with unmapped types, for example:
+AAAA for "printer.lan" or TXT for "otherdevice.lan".
+With `filterUnmappedTypes = true` a query AAAA "printer.lan" will be forwarded to the upstream DNS server.
+
 ## Conditional DNS resolution
 
 You can define, which DNS resolver(s) should be used for queries for the particular domain (with all subdomains). This

go.mod

@@ -29,20 +29,29 @@ require (
 )
 
 require (
+	github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751
 	github.com/avast/retry-go/v4 v4.0.3
 	github.com/go-chi/chi/v5 v5.0.7
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/ncruces/go-dns v1.1.0
 	github.com/onsi/ginkgo/v2 v2.1.3
+	github.com/swaggo/swag v1.8.0
 	gorm.io/driver/postgres v1.3.1
 )
 
 require (
+	github.com/KyleBanks/depth v1.2.1 // indirect
+	github.com/PuerkitoBio/purell v1.1.1 // indirect
+	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
 	github.com/alicebob/gopher-json v0.0.0-20200520072559-a9ecdc9d1d3a // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.19.6 // indirect
+	github.com/go-openapi/spec v0.20.4 // indirect
+	github.com/go-openapi/swag v0.19.15 // indirect
 	github.com/go-sql-driver/mysql v1.6.0 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
@@ -57,7 +66,8 @@ require (
 	github.com/jackc/pgx/v4 v4.14.1 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.4 // indirect
-	github.com/kr/text v0.2.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.6 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/mattn/go-sqlite3 v1.14.9 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect