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|
package blocklist
import (
"bufio"
"net/http"
"os"
"strings"
"sync"
"sync/atomic"
)
type ResponseAction int
const (
ResponseZeroIP ResponseAction = iota
ResponseNXDOMAIN
)
type Blocklist struct {
mu sync.RWMutex
blocked *trie
exceptions *trie
response ResponseAction
TotalRules int32
Hits int64
}
func New(action ResponseAction) *Blocklist {
return &Blocklist{
blocked: newTrie(),
exceptions: newTrie(),
response: action,
}
}
func (b *Blocklist) Response() ResponseAction {
return b.response
}
func (b *Blocklist) IsBlocked(domain string) bool {
b.mu.RLock()
defer b.mu.RUnlock()
labels := splitDomain(domain)
if !b.blocked.match(labels) {
return false
}
if b.exceptions.match(labels) {
return false
}
atomic.AddInt64(&b.Hits, 1)
return true
}
func (b *Blocklist) LoadFile(path string) error {
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
scanner := bufio.NewScanner(f)
var n int32
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
if line == "" || line[0] == '#' || line[0] == '!' {
continue
}
if b.addRule(line) {
n++
}
}
atomic.StoreInt32(&b.TotalRules, n)
return scanner.Err()
}
func (b *Blocklist) LoadURL(url string) error {
resp, err := http.Get(url)
if err != nil {
return err
}
defer resp.Body.Close()
scanner := bufio.NewScanner(resp.Body)
var n int32
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
if line == "" || line[0] == '#' {
continue
}
if b.addRule(line) {
n++
}
}
atomic.AddInt32(&b.TotalRules, n)
return scanner.Err()
}
func (b *Blocklist) addRule(line string) bool {
b.mu.Lock()
defer b.mu.Unlock()
if strings.HasPrefix(line, "@@") {
domain := strings.TrimPrefix(line, "@@")
domain = strings.TrimPrefix(domain, "||")
if idx := strings.Index(domain, "^"); idx > 0 {
domain = domain[:idx]
}
b.exceptions.insert(splitDomain(domain))
return true
}
fields := strings.Fields(line)
if len(fields) >= 2 {
ip := fields[0]
if ip == "0.0.0.0" || ip == "127.0.0.1" || ip == "::1" || ip == "::" {
b.blocked.insert(splitDomain(fields[len(fields)-1]))
return true
}
}
if strings.HasPrefix(line, "||") {
domain := strings.TrimPrefix(line, "||")
if idx := strings.Index(domain, "^"); idx > 0 {
domain = domain[:idx]
}
b.blocked.insert(splitDomain(domain))
return true
}
if strings.Contains(line, ".") && !strings.ContainsAny(line, " /") {
b.blocked.insert(splitDomain(line))
return true
}
return false
}
func splitDomain(domain string) []string {
domain = strings.TrimSuffix(domain, ".")
return strings.Split(domain, ".")
}
type trieNode struct {
children map[string]*trieNode
terminal bool
}
type trie struct{ root *trieNode }
func newTrie() *trie {
return &trie{
root: &trieNode{
children: make(map[string]*trieNode),
},
}
}
func (t *trie) insert(labels []string) {
node := t.root
for i := len(labels) - 1; i >= 0; i-- {
child, ok := node.children[labels[i]]
if !ok {
child = &trieNode{children: make(map[string]*trieNode)}
node.children[labels[i]] = child
}
node = child
}
node.terminal = true
}
func (t *trie) match(labels []string) bool {
node := t.root
for i := len(labels) - 1; i >= 0; i-- {
if node.terminal {
return true
}
child, ok := node.children[labels[i]]
if !ok {
return false
}
node = child
}
return node.terminal
}
|
