* dnsfilter: remove code for filtering rules

dnsfilter/helpers.go

@@ -1,49 +1,9 @@
 package dnsfilter
 
 import (
-	"strings"
 	"sync/atomic"
 )
 
-func isValidRule(rule string) bool {
-	if len(rule) < 4 {
-		return false
-	}
-	if rule[0] == '!' {
-		return false
-	}
-	if rule[0] == '#' {
-		return false
-	}
-	if strings.HasPrefix(rule, "[Adblock") {
-		return false
-	}
-
-	// Filter out all sorts of cosmetic rules:
-	// https://kb.adguard.com/en/general/how-to-create-your-own-ad-filters#cosmetic-rules
-	masks := []string{
-		"##",
-		"#@#",
-		"#?#",
-		"#@?#",
-		"#$#",
-		"#@$#",
-		"#?$#",
-		"#@?$#",
-		"$$",
-		"$@$",
-		"#%#",
-		"#@%#",
-	}
-	for _, mask := range masks {
-		if strings.Contains(rule, mask) {
-			return false
-		}
-	}
-
-	return true
-}
-
 func updateMax(valuePtr *int64, maxPtr *int64) {
 	for {
 		current := atomic.LoadInt64(valuePtr)