AdGuardHome/internal/querylog/decode.go

688 lines
14 KiB
Go

package querylog
import (
"encoding/base64"
"encoding/json"
"fmt"
"io"
"net"
"strings"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/filtering"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/urlfilter/rules"
"github.com/miekg/dns"
)
// logEntryHandler represents a handler for decoding json token to the logEntry
// struct.
type logEntryHandler func(t json.Token, ent *logEntry) error
// logEntryHandlers is the map of log entry decode handlers for various keys.
var logEntryHandlers = map[string]logEntryHandler{
"CID": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
ent.ClientID = v
return nil
},
"IP": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
if ent.IP == nil {
ent.IP = net.ParseIP(v)
}
return nil
},
"T": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
var err error
ent.Time, err = time.Parse(time.RFC3339, v)
return err
},
"QH": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
ent.QHost = v
return nil
},
"QT": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
ent.QType = v
return nil
},
"QC": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
ent.QClass = v
return nil
},
"CP": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
var err error
ent.ClientProto, err = NewClientProto(v)
return err
},
"Answer": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
var err error
ent.Answer, err = base64.StdEncoding.DecodeString(v)
return err
},
"OrigAnswer": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
var err error
ent.OrigAnswer, err = base64.StdEncoding.DecodeString(v)
return err
},
"ECS": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
ent.ReqECS = v
return nil
},
"Cached": func(t json.Token, ent *logEntry) error {
v, ok := t.(bool)
if !ok {
return nil
}
ent.Cached = v
return nil
},
"AD": func(t json.Token, ent *logEntry) error {
v, ok := t.(bool)
if !ok {
return nil
}
ent.AuthenticatedData = v
return nil
},
"Upstream": func(t json.Token, ent *logEntry) error {
v, ok := t.(string)
if !ok {
return nil
}
ent.Upstream = v
return nil
},
"Elapsed": func(t json.Token, ent *logEntry) error {
v, ok := t.(json.Number)
if !ok {
return nil
}
i, err := v.Int64()
if err != nil {
return err
}
ent.Elapsed = time.Duration(i)
return nil
},
}
// decodeResultRuleKey decodes the token of "Rules" type to logEntry struct.
func decodeResultRuleKey(key string, i int, dec *json.Decoder, ent *logEntry) {
var vToken json.Token
switch key {
case "FilterListID":
ent.Result.Rules, vToken = decodeVTokenAndAddRule(key, i, dec, ent.Result.Rules)
if n, ok := vToken.(json.Number); ok {
ent.Result.Rules[i].FilterListID, _ = n.Int64()
}
case "IP":
ent.Result.Rules, vToken = decodeVTokenAndAddRule(key, i, dec, ent.Result.Rules)
if ipStr, ok := vToken.(string); ok {
ent.Result.Rules[i].IP = net.ParseIP(ipStr)
}
case "Text":
ent.Result.Rules, vToken = decodeVTokenAndAddRule(key, i, dec, ent.Result.Rules)
if s, ok := vToken.(string); ok {
ent.Result.Rules[i].Text = s
}
default:
// Go on.
}
}
// decodeVTokenAndAddRule decodes the "Rules" toke as [filtering.ResultRule]
// and then adds the decoded object to the slice of result rules.
func decodeVTokenAndAddRule(
key string,
i int,
dec *json.Decoder,
rules []*filtering.ResultRule,
) (newRules []*filtering.ResultRule, vToken json.Token) {
newRules = rules
vToken, err := dec.Token()
if err != nil {
if err != io.EOF {
log.Debug("decodeResultRuleKey %s err: %s", key, err)
}
return newRules, nil
}
if len(rules) < i+1 {
newRules = append(newRules, &filtering.ResultRule{})
}
return newRules, vToken
}
// decodeResultRules parses the dec's tokens into logEntry ent interpreting it
// as a slice of the result rules.
func decodeResultRules(dec *json.Decoder, ent *logEntry) {
for {
delimToken, err := dec.Token()
if err != nil {
if err != io.EOF {
log.Debug("decodeResultRules err: %s", err)
}
return
}
if d, ok := delimToken.(json.Delim); !ok {
return
} else if d != '[' {
log.Debug("decodeResultRules: unexpected delim %q", d)
}
err = decodeResultRuleToken(dec, ent)
if err != nil {
if err != io.EOF && !errors.Is(err, ErrEndOfToken) {
log.Debug("decodeResultRules err: %s", err)
}
return
}
}
}
// decodeResultRuleToken decodes the tokens of "Rules" type to the logEntry ent.
func decodeResultRuleToken(dec *json.Decoder, ent *logEntry) (err error) {
i := 0
for {
var keyToken json.Token
keyToken, err = dec.Token()
if err != nil {
// Don't wrap the error, because it's informative enough as is.
return err
}
if d, ok := keyToken.(json.Delim); ok {
switch d {
case '}':
i++
case ']':
return ErrEndOfToken
default:
// Go on.
}
continue
}
key, ok := keyToken.(string)
if !ok {
return fmt.Errorf("keyToken is %T (%[1]v) and not string", keyToken)
}
decodeResultRuleKey(key, i, dec, ent)
}
}
// decodeResultReverseHosts parses the dec's tokens into ent interpreting it as
// the result of hosts container's $dnsrewrite rule. It assumes there are no
// other occurrences of DNSRewriteResult in the entry since hosts container's
// rewrites currently has the highest priority along the entire filtering
// pipeline.
func decodeResultReverseHosts(dec *json.Decoder, ent *logEntry) {
for {
itemToken, err := dec.Token()
if err != nil {
if err != io.EOF {
log.Debug("decodeResultReverseHosts err: %s", err)
}
return
}
switch v := itemToken.(type) {
case json.Delim:
if v == '[' {
continue
} else if v == ']' {
return
}
log.Debug("decodeResultReverseHosts: unexpected delim %q", v)
return
case string:
v = dns.Fqdn(v)
if res := &ent.Result; res.DNSRewriteResult == nil {
res.DNSRewriteResult = &filtering.DNSRewriteResult{
RCode: dns.RcodeSuccess,
Response: filtering.DNSRewriteResultResponse{
dns.TypePTR: []rules.RRValue{v},
},
}
continue
} else {
res.DNSRewriteResult.RCode = dns.RcodeSuccess
}
if rres := ent.Result.DNSRewriteResult; rres.Response == nil {
rres.Response = filtering.DNSRewriteResultResponse{dns.TypePTR: []rules.RRValue{v}}
} else {
rres.Response[dns.TypePTR] = append(rres.Response[dns.TypePTR], v)
}
default:
continue
}
}
}
// decodeResultIPList parses the dec's tokens into logEntry ent interpreting it
// as the result IP addresses list.
func decodeResultIPList(dec *json.Decoder, ent *logEntry) {
for {
itemToken, err := dec.Token()
if err != nil {
if err != io.EOF {
log.Debug("decodeResultIPList err: %s", err)
}
return
}
switch v := itemToken.(type) {
case json.Delim:
if v == '[' {
continue
} else if v == ']' {
return
}
log.Debug("decodeResultIPList: unexpected delim %q", v)
return
case string:
ip := net.ParseIP(v)
if ip != nil {
ent.Result.IPList = append(ent.Result.IPList, ip)
}
default:
continue
}
}
}
// decodeResultDNSRewriteResultKey decodes the token of "DNSRewriteResult" type
// to the logEntry struct.
func decodeResultDNSRewriteResultKey(key string, dec *json.Decoder, ent *logEntry) {
var err error
switch key {
case "RCode":
var vToken json.Token
vToken, err = dec.Token()
if err != nil {
if err != io.EOF {
log.Debug("decodeResultDNSRewriteResultKey err: %s", err)
}
return
}
if ent.Result.DNSRewriteResult == nil {
ent.Result.DNSRewriteResult = &filtering.DNSRewriteResult{}
}
if n, ok := vToken.(json.Number); ok {
rcode64, _ := n.Int64()
ent.Result.DNSRewriteResult.RCode = rules.RCode(rcode64)
}
case "Response":
if ent.Result.DNSRewriteResult == nil {
ent.Result.DNSRewriteResult = &filtering.DNSRewriteResult{}
}
if ent.Result.DNSRewriteResult.Response == nil {
ent.Result.DNSRewriteResult.Response = filtering.DNSRewriteResultResponse{}
}
// TODO(a.garipov): I give up. This whole file is a mess. Luckily, we
// can assume that this field is relatively rare and just use the normal
// decoding and correct the values.
err = dec.Decode(&ent.Result.DNSRewriteResult.Response)
if err != nil {
log.Debug("decodeResultDNSRewriteResultKey response err: %s", err)
}
ent.parseDNSRewriteResultIPs()
default:
// Go on.
}
}
// decodeResultDNSRewriteResult parses the dec's tokens into logEntry ent
// interpreting it as the result DNSRewriteResult.
func decodeResultDNSRewriteResult(dec *json.Decoder, ent *logEntry) {
for {
key, err := parseKeyToken(dec)
if err != nil {
if err != io.EOF && !errors.Is(err, ErrEndOfToken) {
log.Debug("decodeResultDNSRewriteResult: %s", err)
}
return
}
if key == "" {
continue
}
decodeResultDNSRewriteResultKey(key, dec, ent)
}
}
// translateResult converts some fields of the ent.Result to the format
// consistent with current implementation.
func translateResult(ent *logEntry) {
res := &ent.Result
if res.Reason != filtering.RewrittenAutoHosts || len(res.IPList) == 0 {
return
}
if res.DNSRewriteResult == nil {
res.DNSRewriteResult = &filtering.DNSRewriteResult{
RCode: dns.RcodeSuccess,
}
}
if res.DNSRewriteResult.Response == nil {
res.DNSRewriteResult.Response = filtering.DNSRewriteResultResponse{}
}
resp := res.DNSRewriteResult.Response
for _, ip := range res.IPList {
qType := dns.TypeAAAA
if ip.To4() != nil {
qType = dns.TypeA
}
resp[qType] = append(resp[qType], ip)
}
res.IPList = nil
}
// ErrEndOfToken is an error returned by parse key token when the closing
// bracket is found.
const ErrEndOfToken errors.Error = "end of token"
// parseKeyToken parses the dec's token key.
func parseKeyToken(dec *json.Decoder) (key string, err error) {
keyToken, err := dec.Token()
if err != nil {
return "", err
}
if d, ok := keyToken.(json.Delim); ok {
if d == '}' {
return "", ErrEndOfToken
}
return "", nil
}
key, ok := keyToken.(string)
if !ok {
return "", fmt.Errorf("keyToken is %T (%[1]v) and not string", keyToken)
}
return key, nil
}
// decodeResult decodes a token of "Result" type to logEntry struct.
func decodeResult(dec *json.Decoder, ent *logEntry) {
defer translateResult(ent)
for {
key, err := parseKeyToken(dec)
if err != nil {
if err != io.EOF && !errors.Is(err, ErrEndOfToken) {
log.Debug("decodeResult: %s", err)
}
return
}
if key == "" {
continue
}
decHandler, ok := resultDecHandlers[key]
if ok {
decHandler(dec, ent)
continue
}
handler, ok := resultHandlers[key]
if !ok {
continue
}
val, err := dec.Token()
if err != nil {
return
}
if err = handler(val, ent); err != nil {
log.Debug("decodeResult handler err: %s", err)
return
}
}
}
// resultHandlers is the map of log entry decode handlers for various keys.
var resultHandlers = map[string]logEntryHandler{
"IsFiltered": func(t json.Token, ent *logEntry) error {
v, ok := t.(bool)
if !ok {
return nil
}
ent.Result.IsFiltered = v
return nil
},
"Rule": func(t json.Token, ent *logEntry) error {
s, ok := t.(string)
if !ok {
return nil
}
l := len(ent.Result.Rules)
if l == 0 {
ent.Result.Rules = []*filtering.ResultRule{{}}
l++
}
ent.Result.Rules[l-1].Text = s
return nil
},
"FilterID": func(t json.Token, ent *logEntry) error {
n, ok := t.(json.Number)
if !ok {
return nil
}
i, err := n.Int64()
if err != nil {
return err
}
l := len(ent.Result.Rules)
if l == 0 {
ent.Result.Rules = []*filtering.ResultRule{{}}
l++
}
ent.Result.Rules[l-1].FilterListID = i
return nil
},
"Reason": func(t json.Token, ent *logEntry) error {
v, ok := t.(json.Number)
if !ok {
return nil
}
i, err := v.Int64()
if err != nil {
return err
}
ent.Result.Reason = filtering.Reason(i)
return nil
},
"ServiceName": func(t json.Token, ent *logEntry) error {
s, ok := t.(string)
if !ok {
return nil
}
ent.Result.ServiceName = s
return nil
},
"CanonName": func(t json.Token, ent *logEntry) error {
s, ok := t.(string)
if !ok {
return nil
}
ent.Result.CanonName = s
return nil
},
}
// resultDecHandlers is the map of decode handlers for various keys.
var resultDecHandlers = map[string]func(dec *json.Decoder, ent *logEntry){
"ReverseHosts": decodeResultReverseHosts,
"IPList": decodeResultIPList,
"Rules": decodeResultRules,
"DNSRewriteResult": decodeResultDNSRewriteResult,
}
// decodeLogEntry decodes string str to logEntry ent.
func decodeLogEntry(ent *logEntry, str string) {
dec := json.NewDecoder(strings.NewReader(str))
dec.UseNumber()
for {
keyToken, err := dec.Token()
if err != nil {
if err != io.EOF {
log.Debug("decodeLogEntry err: %s", err)
}
return
}
if _, ok := keyToken.(json.Delim); ok {
continue
}
key, ok := keyToken.(string)
if !ok {
log.Debug("decodeLogEntry: keyToken is %T (%[1]v) and not string", keyToken)
return
}
if key == "Result" {
decodeResult(dec, ent)
continue
}
handler, ok := logEntryHandlers[key]
if !ok {
continue
}
val, err := dec.Token()
if err != nil {
return
}
if err = handler(val, ent); err != nil {
log.Debug("decodeLogEntry handler err: %s", err)
return
}
}
}