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Merge: + DNS: use rules from /etc/hosts

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- fix filtering logic: don't do DNS response check for Rewrite rules

Close #1478

Squashed commit of the following:

commit 1206b94881289ff664b7c8998ea97c1455da1ff8
Merge: c462577a 5fe98474
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Mar 20 15:00:25 2020 +0300

    Merge remote-tracking branch 'origin/master' into 1478-auto-records

commit c462577ad84754f5b3ea4cd58339838af817fe36
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Mar 20 14:33:17 2020 +0300

    minor

commit 7e824ba5f432648a976bc4b8076a645ba875ef70
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Mar 20 14:29:54 2020 +0300

    more tests

commit a22b62136c5cfd84cd0450897aef9e7d2e20585a
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Mar 20 14:09:52 2020 +0300

    rename, move

commit 9e5ed49ad3c27c57d540edf18b78d29e56afb067
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Mar 19 15:33:27 2020 +0300

    fix logic - don't do DNS response check for Rewrite rules

commit 6cfabc0348a41883b8bba834626a7e8760b76bf2
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Mar 19 11:35:07 2020 +0300

    minor

commit 4540aed9327566078e5087d43c30f4e8bffab7b9
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Mar 19 11:03:24 2020 +0300

    fix

commit 9ddddf7bded812da48613cc07084e360c15ddd0e
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Mar 19 10:49:13 2020 +0300

    fix

commit c5f8ef745b6f2a768be8a2ab23ad80b01b0aa54f
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Mar 19 10:37:26 2020 +0300

    fix

commit f4be00947bf0528c9a7cd4f09c4090db444c4694
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Mon Mar 16 20:13:00 2020 +0300

    + auto DNS records from /etc/hosts
This commit is contained in:
Simon Zolin
2020-03-20 15:05:43 +03:00
parent 5fe984741e
commit 63923fa882
13 changed files with 403 additions and 58 deletions
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246
util/auto_hosts.go Normal file
View File

@@ -0,0 +1,246 @@
package util
import (
"bufio"
"io"
"io/ioutil"
"net"
"os"
"runtime"
"strings"
"sync"
"github.com/AdguardTeam/golibs/log"
"github.com/fsnotify/fsnotify"
)
type onChangedT func()
// AutoHosts - automatic DNS records
type AutoHosts struct {
lock sync.Mutex // serialize access to table
table map[string][]net.IP // 'hostname -> IP' table
hostsFn string // path to the main hosts-file
hostsDirs []string // paths to OS-specific directories with hosts-files
watcher *fsnotify.Watcher // file and directory watcher object
updateChan chan bool // signal for 'update' goroutine
onChanged onChangedT // notification to other modules
}
// SetOnChanged - set callback function that will be called when the data is changed
func (a *AutoHosts) SetOnChanged(onChanged onChangedT) {
a.onChanged = onChanged
}
// Notify other modules
func (a *AutoHosts) notify() {
if a.onChanged == nil {
return
}
a.onChanged()
}
// Init - initialize
// hostsFn: Override default name for the hosts-file (optional)
func (a *AutoHosts) Init(hostsFn string) {
a.table = make(map[string][]net.IP)
a.updateChan = make(chan bool, 2)
a.hostsFn = "/etc/hosts"
if runtime.GOOS == "windows" {
a.hostsFn = os.ExpandEnv("$SystemRoot\\system32\\drivers\\etc\\hosts")
}
if len(hostsFn) != 0 {
a.hostsFn = hostsFn
}
if IsOpenWrt() {
a.hostsDirs = append(a.hostsDirs, "/tmp/hosts") // OpenWRT: "/tmp/hosts/dhcp.cfg01411c"
}
var err error
a.watcher, err = fsnotify.NewWatcher()
if err != nil {
log.Error("AutoHosts: %s", err)
}
}
// Start - start module
func (a *AutoHosts) Start() {
go a.update()
a.updateChan <- true
go a.watcherLoop()
err := a.watcher.Add(a.hostsFn)
if err != nil {
log.Error("AutoHosts: %s", err)
}
for _, dir := range a.hostsDirs {
err = a.watcher.Add(dir)
if err != nil {
log.Error("AutoHosts: %s", err)
}
}
}
// Close - close module
func (a *AutoHosts) Close() {
a.updateChan <- false
a.watcher.Close()
}
// Read IP-hostname pairs from file
// Multiple hostnames per line (per one IP) is supported.
func (a *AutoHosts) load(table map[string][]net.IP, fn string) {
f, err := os.Open(fn)
if err != nil {
log.Error("AutoHosts: %s", err)
return
}
defer f.Close()
r := bufio.NewReader(f)
log.Debug("AutoHosts: loading hosts from file %s", fn)
finish := false
for !finish {
line, err := r.ReadString('\n')
if err == io.EOF {
finish = true
} else if err != nil {
log.Error("AutoHosts: %s", err)
return
}
line = strings.TrimSpace(line)
ip := SplitNext(&line, ' ')
ipAddr := net.ParseIP(ip)
if ipAddr == nil {
continue
}
for {
host := SplitNext(&line, ' ')
if len(host) == 0 {
break
}
ips, ok := table[host]
if ok {
for _, ip := range ips {
if ip.Equal(ipAddr) {
// IP already exists: don't add duplicates
ok = false
break
}
}
if !ok {
ips = append(ips, ipAddr)
table[host] = ips
}
} else {
table[host] = []net.IP{ipAddr}
ok = true
}
if ok {
log.Debug("AutoHosts: added %s -> %s", ip, host)
}
}
}
}
// Receive notifications from fsnotify package
func (a *AutoHosts) watcherLoop() {
for {
select {
case event, ok := <-a.watcher.Events:
if !ok {
return
}
// skip duplicate events
repeat := true
for repeat {
select {
case _ = <-a.watcher.Events:
// skip this event
default:
repeat = false
}
}
if event.Op&fsnotify.Write == fsnotify.Write {
log.Debug("AutoHosts: modified: %s", event.Name)
select {
case a.updateChan <- true:
// sent a signal to 'update' goroutine
default:
// queue is full
}
}
case err, ok := <-a.watcher.Errors:
if !ok {
return
}
log.Error("AutoHosts: %s", err)
}
}
}
// Read static hosts from system files
func (a *AutoHosts) update() {
for {
select {
case ok := <-a.updateChan:
if !ok {
return
}
table := make(map[string][]net.IP)
a.load(table, a.hostsFn)
for _, dir := range a.hostsDirs {
fis, err := ioutil.ReadDir(dir)
if err != nil {
if !os.IsNotExist(err) {
log.Error("AutoHosts: Opening directory: %s: %s", dir, err)
}
continue
}
for _, fi := range fis {
a.load(table, dir+"/"+fi.Name())
}
}
a.lock.Lock()
a.table = table
a.lock.Unlock()
a.notify()
}
}
}
// Process - get the list of IP addresses for the hostname
func (a *AutoHosts) Process(host string) []net.IP {
a.lock.Lock()
ips, _ := a.table[host]
ipsCopy := make([]net.IP, len(ips))
copy(ipsCopy, ips)
a.lock.Unlock()
return ipsCopy
}
// List - get the hosts table. Thread-safe.
func (a *AutoHosts) List() map[string][]net.IP {
table := make(map[string][]net.IP)
a.lock.Lock()
for k, v := range a.table {
table[k] = v
}
a.lock.Unlock()
return table
}

54
util/auto_hosts_test.go Normal file
View File

@@ -0,0 +1,54 @@
package util
import (
"io/ioutil"
"net"
"os"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
func prepareTestDir() string {
const dir = "./agh-test"
_ = os.RemoveAll(dir)
_ = os.MkdirAll(dir, 0755)
return dir
}
func TestAutoHosts(t *testing.T) {
ah := AutoHosts{}
dir := prepareTestDir()
defer func() { _ = os.RemoveAll(dir) }()
f, _ := ioutil.TempFile(dir, "")
defer os.Remove(f.Name())
defer f.Close()
_, _ = f.WriteString(" 127.0.0.1 host localhost \n")
ah.Init(f.Name())
ah.Start()
// wait until we parse the file
time.Sleep(50 * time.Millisecond)
ips := ah.Process("localhost")
assert.True(t, ips[0].Equal(net.ParseIP("127.0.0.1")))
ips = ah.Process("newhost")
assert.True(t, len(ips) == 0)
table := ah.List()
ips, _ = table["host"]
assert.True(t, ips[0].String() == "127.0.0.1")
_, _ = f.WriteString("127.0.0.2 newhost\n")
// wait until fsnotify has triggerred and processed the file-modification event
time.Sleep(50 * time.Millisecond)
ips = ah.Process("newhost")
assert.True(t, ips[0].Equal(net.ParseIP("127.0.0.2")))
ah.Close()
}

24
util/helpers.go
View File

@@ -2,6 +2,7 @@ package util
import (
"fmt"
"io/ioutil"
"os"
"os/exec"
"path"
@@ -37,6 +38,7 @@ func FuncName() string {
}
// SplitNext - split string by a byte and return the first chunk
// Skip empty chunks
// Whitespace is trimmed
func SplitNext(str *string, splitBy byte) string {
i := strings.IndexByte(*str, splitBy)
@@ -44,6 +46,14 @@ func SplitNext(str *string, splitBy byte) string {
if i != -1 {
s = (*str)[0:i]
*str = (*str)[i+1:]
k := 0
ch := rune(0)
for k, ch = range *str {
if byte(ch) != splitBy {
break
}
}
*str = (*str)[k:]
} else {
s = *str
*str = ""
@@ -58,3 +68,17 @@ func MinInt(a, b int) int {
}
return b
}
// IsOpenWrt checks if OS is OpenWRT
func IsOpenWrt() bool {
if runtime.GOOS != "linux" {
return false
}
body, err := ioutil.ReadFile("/etc/os-release")
if err != nil {
return false
}
return strings.Contains(string(body), "OpenWrt")
}