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Pull request 2080: AG-27539 imp upstream test

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Squashed commit of the following:

commit 5a9e8c0c2e4b68c0ff6508c47fbd8abde0d05e95
Merge: 85820c173 c4e69cd96
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 28 16:09:53 2023 +0300

    Merge branch 'master' into AG-27539-imp-upstream-test

commit 85820c173dddb6391dabe9615b821b585b1ecdef
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 28 15:48:53 2023 +0300

    dnsforward: split code

commit dac0148a4d4780bea19fb7622b46ac08fbf1ee74
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Nov 24 15:47:05 2023 +0300

    dnsforward: fix docs

commit 9f0015b255d547f31d34513aa6bb2faf65a39e0e
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Nov 24 14:45:43 2023 +0300

    dnsforward: imp code

commit 49fefc373972b7c8991abcb46d7730288b92c24c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Thu Nov 23 14:12:02 2023 +0300

    dnsforward: imp code

commit 120ba4b1f727bba537471c4a8aa4b412eac30f85
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Nov 22 17:02:01 2023 +0300

    dnsforward: add tests

commit 70775975ced46191a6ba64504c7bac0e3d1eed7f
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Nov 22 15:48:05 2023 +0300

    dnsforward: imp code

commit 9487f1fd62b821efb242267d9972f3ae3785ad19
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 21 18:06:00 2023 +0300

    dnsforward: imp code

commit e2612e0e6fd1c9116872939edd0e86f2e9af07d7
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 21 16:12:20 2023 +0300

    dnsforward: add ups checker

commit 09db7d2a604809669affbeef2f0536fa6605a39b
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 14 17:31:04 2023 +0300

    dnsforward: separate upstream code
This commit is contained in:
Eugene Burkov 2023-11-28 16:40:52 +03:00
parent c4e69cd961
commit 849abaf25e
6 changed files with 785 additions and 506 deletions
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349
internal/dnsforward/configvalidator.go Normal file
View file

@ -0,0 +1,349 @@
package dnsforward
import (
"fmt"
"strings"
"sync"
"github.com/AdguardTeam/dnsproxy/upstream"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/miekg/dns"
"golang.org/x/exp/slices"
)
// upstreamConfigValidator parses the [*proxy.UpstreamConfig] and checks the
// actual DNS availability of each upstream.
type upstreamConfigValidator struct {
// general is the general upstream configuration.
general []*upstreamResult
// fallback is the fallback upstream configuration.
fallback []*upstreamResult
// private is the private upstream configuration.
private []*upstreamResult
}
// upstreamResult is a result of validation of an [upstream.Upstream] within an
// [proxy.UpstreamConfig].
type upstreamResult struct {
// server is the parsed upstream. It is nil when there was an error during
// parsing.
server upstream.Upstream
// err is the error either from parsing or from checking the upstream.
err error
// original is the piece of configuration that have either been turned to an
// upstream or caused an error.
original string
// isSpecific is true if the upstream is domain-specific.
isSpecific bool
}
// compare compares two [upstreamResult]s. It returns 0 if they are equal, -1
// if ur should be sorted before other, and 1 otherwise.
//
// TODO(e.burkov): Perhaps it makes sense to sort the results with errors near
// the end.
func (ur *upstreamResult) compare(other *upstreamResult) (res int) {
return strings.Compare(ur.original, other.original)
}
// newUpstreamConfigValidator parses the upstream configuration and returns a
// validator for it. cv already contains the parsed upstreams along with errors
// related.
func newUpstreamConfigValidator(
general []string,
fallback []string,
private []string,
opts *upstream.Options,
) (cv *upstreamConfigValidator) {
cv = &upstreamConfigValidator{}
for _, line := range general {
cv.general = cv.insertLineResults(cv.general, line, opts)
}
for _, line := range fallback {
cv.fallback = cv.insertLineResults(cv.fallback, line, opts)
}
for _, line := range private {
cv.private = cv.insertLineResults(cv.private, line, opts)
}
return cv
}
// insertLineResults parses line and inserts the result into s. It can insert
// multiple results as well as none.
func (cv *upstreamConfigValidator) insertLineResults(
s []*upstreamResult,
line string,
opts *upstream.Options,
) (result []*upstreamResult) {
upstreams, isSpecific, err := splitUpstreamLine(line)
if err != nil {
return cv.insert(s, &upstreamResult{
err: err,
original: line,
})
}
for _, upstreamAddr := range upstreams {
var res *upstreamResult
if upstreamAddr != "#" {
res = cv.parseUpstream(upstreamAddr, opts)
} else if !isSpecific {
res = &upstreamResult{
err: errNotDomainSpecific,
original: upstreamAddr,
}
} else {
continue
}
res.isSpecific = isSpecific
s = cv.insert(s, res)
}
return s
}
// insert inserts r into slice in a sorted order, except duplicates. slice must
// not be nil.
func (cv *upstreamConfigValidator) insert(
s []*upstreamResult,
r *upstreamResult,
) (result []*upstreamResult) {
i, has := slices.BinarySearchFunc(s, r, (*upstreamResult).compare)
if has {
log.Debug("dnsforward: duplicate configuration %q", r.original)
return s
}
return slices.Insert(s, i, r)
}
// parseUpstream parses addr and returns the result of parsing. It returns nil
// if the specified server points at the default upstream server which is
// validated separately.
func (cv *upstreamConfigValidator) parseUpstream(
addr string,
opts *upstream.Options,
) (r *upstreamResult) {
// Check if the upstream has a valid protocol prefix.
//
// TODO(e.burkov): Validate the domain name.
if proto, _, ok := strings.Cut(addr, "://"); ok {
if !slices.Contains(protocols, proto) {
return &upstreamResult{
err: fmt.Errorf("bad protocol %q", proto),
original: addr,
}
}
}
ups, err := upstream.AddressToUpstream(addr, opts)
return &upstreamResult{
server: ups,
err: err,
original: addr,
}
}
// check tries to exchange with each successfully parsed upstream and enriches
// the results with the healthcheck errors. It should not be called after the
// [upsConfValidator.close] method, since it makes no sense to check the closed
// upstreams.
func (cv *upstreamConfigValidator) check() {
const (
// testTLD is the special-use fully-qualified domain name for testing
// the DNS server reachability.
//
// See https://datatracker.ietf.org/doc/html/rfc6761#section-6.2.
testTLD = "test."
// inAddrARPATLD is the special-use fully-qualified domain name for PTR
// IP address resolution.
//
// See https://datatracker.ietf.org/doc/html/rfc1035#section-3.5.
inAddrARPATLD = "in-addr.arpa."
)
commonChecker := &healthchecker{
hostname: testTLD,
qtype: dns.TypeA,
ansEmpty: true,
}
arpaChecker := &healthchecker{
hostname: inAddrARPATLD,
qtype: dns.TypePTR,
ansEmpty: false,
}
wg := &sync.WaitGroup{}
wg.Add(len(cv.general) + len(cv.fallback) + len(cv.private))
for _, res := range cv.general {
go cv.checkSrv(res, wg, commonChecker)
}
for _, res := range cv.fallback {
go cv.checkSrv(res, wg, commonChecker)
}
for _, res := range cv.private {
go cv.checkSrv(res, wg, arpaChecker)
}
wg.Wait()
}
// checkSrv runs hc on the server from res, if any, and stores any occurred
// error in res. wg is always marked done in the end. It used to be called in
// a separate goroutine.
func (cv *upstreamConfigValidator) checkSrv(
res *upstreamResult,
wg *sync.WaitGroup,
hc *healthchecker,
) {
defer wg.Done()
if res.server == nil {
return
}
res.err = hc.check(res.server)
if res.err != nil && res.isSpecific {
res.err = domainSpecificTestError{Err: res.err}
}
}
// close closes all the upstreams that were successfully parsed. It enriches
// the results with deferred closing errors.
func (cv *upstreamConfigValidator) close() {
for _, slice := range [][]*upstreamResult{cv.general, cv.fallback, cv.private} {
for _, r := range slice {
if r.server != nil {
r.err = errors.WithDeferred(r.err, r.server.Close())
}
}
}
}
// status returns all the data collected during parsing, healthcheck, and
// closing of the upstreams. The returned map is keyed by the original upstream
// configuration piece and contains the corresponding error or "OK" if there was
// no error.
func (cv *upstreamConfigValidator) status() (results map[string]string) {
result := map[string]string{}
for _, res := range cv.general {
resultToStatus("general", res, result)
}
for _, res := range cv.fallback {
resultToStatus("fallback", res, result)
}
for _, res := range cv.private {
resultToStatus("private", res, result)
}
return result
}
// resultToStatus puts "OK" or an error message from res into resMap. section
// is the name of the upstream configuration section, i.e. "general",
// "fallback", or "private", and only used for logging.
//
// TODO(e.burkov): Currently, the HTTP handler expects that all the results are
// put together in a single map, which may lead to collisions, see AG-27539.
// Improve the results compilation.
func resultToStatus(section string, res *upstreamResult, resMap map[string]string) {
val := "OK"
if res.err != nil {
val = res.err.Error()
}
prevVal := resMap[res.original]
switch prevVal {
case "":
resMap[res.original] = val
case val:
log.Debug("dnsforward: duplicating %s config line %q", section, res.original)
default:
log.Debug(
"dnsforward: warning: %s config line %q (%v) had different result %v",
section,
val,
res.original,
prevVal,
)
}
}
// domainSpecificTestError is a wrapper for errors returned by checkDNS to mark
// the tested upstream domain-specific and therefore consider its errors
// non-critical.
//
// TODO(a.garipov): Some common mechanism of distinguishing between errors and
// warnings (non-critical errors) is desired.
type domainSpecificTestError struct {
// Err is the actual error occurred during healthcheck test.
Err error
}
// type check
var _ error = domainSpecificTestError{}
// Error implements the [error] interface for domainSpecificTestError.
func (err domainSpecificTestError) Error() (msg string) {
return fmt.Sprintf("WARNING: %s", err.Err)
}
// type check
var _ errors.Wrapper = domainSpecificTestError{}
// Unwrap implements the [errors.Wrapper] interface for domainSpecificTestError.
func (err domainSpecificTestError) Unwrap() (wrapped error) {
return err.Err
}
// healthchecker checks the upstream's status by exchanging with it.
type healthchecker struct {
// hostname is the name of the host to put into healthcheck DNS request.
hostname string
// qtype is the type of DNS request to use for healthcheck.
qtype uint16
// ansEmpty defines if the answer section within the response is expected to
// be empty.
ansEmpty bool
}
// check exchanges with u and validates the response.
func (h *healthchecker) check(u upstream.Upstream) (err error) {
req := &dns.Msg{
MsgHdr: dns.MsgHdr{
Id: dns.Id(),
RecursionDesired: true,
},
Question: []dns.Question{{
Name: h.hostname,
Qtype: h.qtype,
Qclass: dns.ClassINET,
}},
}
reply, err := u.Exchange(req)
if err != nil {
return fmt.Errorf("couldn't communicate with upstream: %w", err)
} else if h.ansEmpty && len(reply.Answer) > 0 {
return errWrongResponse
}
return nil
}

10
internal/dnsforward/dnsforward.go
View file

@ -35,6 +35,11 @@ import (
// DefaultTimeout is the default upstream timeout
const DefaultTimeout = 10 * time.Second
// defaultLocalTimeout is the default timeout for resolving addresses from
// locally-served networks. It is assumed that local resolvers should work much
// faster than ordinary upstreams.
const defaultLocalTimeout = 1 * time.Second
// defaultClientIDCacheCount is the default count of items in the LRU ClientID
// cache. The assumption here is that there won't be more than this many
// requests between the BeforeRequestHandler stage and the actual processing.
@ -459,11 +464,6 @@ func (s *Server) startLocked() error {
return err
}
// defaultLocalTimeout is the default timeout for resolving addresses from
// locally-served networks. It is assumed that local resolvers should work much
// faster than ordinary upstreams.
const defaultLocalTimeout = 1 * time.Second
// setupLocalResolvers initializes the resolvers for local addresses. It
// assumes s.serverLock is locked or the Server not running.
func (s *Server) setupLocalResolvers(boot upstream.Resolver) (err error) {

398
internal/dnsforward/http.go
View file

@ -4,23 +4,17 @@ import (
"encoding/json"
"fmt"
"io"
"net"
"net/http"
"net/netip"
"strings"
"sync"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
"github.com/AdguardTeam/AdGuardHome/internal/filtering"
"github.com/AdguardTeam/dnsproxy/proxy"
"github.com/AdguardTeam/dnsproxy/upstream"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/golibs/netutil"
"github.com/AdguardTeam/golibs/stringutil"
"github.com/miekg/dns"
"golang.org/x/exp/maps"
"golang.org/x/exp/slices"
)
@ -546,365 +540,6 @@ type upstreamJSON struct {
PrivateUpstreams []string `json:"private_upstream"`
}
// IsCommentOrEmpty returns true if s starts with a "#" character or is empty.
// This function is useful for filtering out non-upstream lines from upstream
// configs.
func IsCommentOrEmpty(s string) (ok bool) {
return len(s) == 0 || s[0] == '#'
}
// newUpstreamConfig validates upstreams and returns an appropriate upstream
// configuration or nil if it can't be built.
//
// TODO(e.burkov): Perhaps proxy.ParseUpstreamsConfig should validate upstreams
// slice already so that this function may be considered useless.
func newUpstreamConfig(upstreams []string) (conf *proxy.UpstreamConfig, err error) {
// No need to validate comments and empty lines.
upstreams = stringutil.FilterOut(upstreams, IsCommentOrEmpty)
if len(upstreams) == 0 {
// Consider this case valid since it means the default server should be
// used.
return nil, nil
}
err = validateUpstreamConfig(upstreams)
if err != nil {
// Don't wrap the error since it's informative enough as is.
return nil, err
}
conf, err = proxy.ParseUpstreamsConfig(
upstreams,
&upstream.Options{
Bootstrap: net.DefaultResolver,
Timeout: DefaultTimeout,
},
)
if err != nil {
// Don't wrap the error since it's informative enough as is.
return nil, err
} else if len(conf.Upstreams) == 0 {
return nil, errors.Error("no default upstreams specified")
}
return conf, nil
}
// validateUpstreamConfig validates each upstream from the upstream
// configuration and returns an error if any upstream is invalid.
//
// TODO(e.burkov): Move into aghnet or even into dnsproxy.
func validateUpstreamConfig(conf []string) (err error) {
for _, u := range conf {
var ups []string
var domains []string
ups, domains, err = separateUpstream(u)
if err != nil {
// Don't wrap the error since it's informative enough as is.
return err
}
for _, addr := range ups {
_, err = validateUpstream(addr, domains)
if err != nil {
return fmt.Errorf("validating upstream %q: %w", addr, err)
}
}
}
return nil
}
// ValidateUpstreams validates each upstream and returns an error if any
// upstream is invalid or if there are no default upstreams specified.
//
// TODO(e.burkov): Move into aghnet or even into dnsproxy.
func ValidateUpstreams(upstreams []string) (err error) {
_, err = newUpstreamConfig(upstreams)
return err
}
// ValidateUpstreamsPrivate validates each upstream and returns an error if any
// upstream is invalid or if there are no default upstreams specified. It also
// checks each domain of domain-specific upstreams for being ARPA pointing to
// a locally-served network. privateNets must not be nil.
func ValidateUpstreamsPrivate(upstreams []string, privateNets netutil.SubnetSet) (err error) {
conf, err := newUpstreamConfig(upstreams)
if err != nil {
return fmt.Errorf("creating config: %w", err)
}
if conf == nil {
return nil
}
keys := maps.Keys(conf.DomainReservedUpstreams)
slices.Sort(keys)
var errs []error
for _, domain := range keys {
var subnet netip.Prefix
subnet, err = extractARPASubnet(domain)
if err != nil {
errs = append(errs, err)
continue
}
if !privateNets.Contains(subnet.Addr().AsSlice()) {
errs = append(
errs,
fmt.Errorf("arpa domain %q should point to a locally-served network", domain),
)
}
}
return errors.Annotate(errors.Join(errs...), "checking domain-specific upstreams: %w")
}
var protocols = []string{
"h3://",
"https://",
"quic://",
"sdns://",
"tcp://",
"tls://",
"udp://",
}
// validateUpstream returns an error if u alongside with domains is not a valid
// upstream configuration. useDefault is true if the upstream is
// domain-specific and is configured to point at the default upstream server
// which is validated separately. The upstream is considered domain-specific
// only if domains is at least not nil.
func validateUpstream(u string, domains []string) (useDefault bool, err error) {
// The special server address '#' means that default server must be used.
if useDefault = u == "#" && domains != nil; useDefault {
return useDefault, nil
}
// Check if the upstream has a valid protocol prefix.
//
// TODO(e.burkov): Validate the domain name.
for _, proto := range protocols {
if strings.HasPrefix(u, proto) {
return false, nil
}
}
if proto, _, ok := strings.Cut(u, "://"); ok {
return false, fmt.Errorf("bad protocol %q", proto)
}
// Check if upstream is either an IP or IP with port.
if _, err = netip.ParseAddr(u); err == nil {
return false, nil
} else if _, err = netip.ParseAddrPort(u); err == nil {
return false, nil
}
return false, err
}
// separateUpstream returns the upstreams and the specified domains. domains
// is nil when the upstream is not domains-specific. Otherwise it may also be
// empty.
func separateUpstream(upstreamStr string) (upstreams, domains []string, err error) {
if !strings.HasPrefix(upstreamStr, "[/") {
return []string{upstreamStr}, nil, nil
}
defer func() { err = errors.Annotate(err, "bad upstream for domain %q: %w", upstreamStr) }()
parts := strings.Split(upstreamStr[2:], "/]")
switch len(parts) {
case 2:
// Go on.
case 1:
return nil, nil, errors.Error("missing separator")
default:
return nil, nil, errors.Error("duplicated separator")
}
for i, host := range strings.Split(parts[0], "/") {
if host == "" {
continue
}
err = netutil.ValidateDomainName(strings.TrimPrefix(host, "*."))
if err != nil {
return nil, nil, fmt.Errorf("domain at index %d: %w", i, err)
}
domains = append(domains, host)
}
return strings.Fields(parts[1]), domains, nil
}
// healthCheckFunc is a signature of function to check if upstream exchanges
// properly.
type healthCheckFunc func(u upstream.Upstream) (err error)
// checkDNSUpstreamExc checks if the DNS upstream exchanges correctly.
func checkDNSUpstreamExc(u upstream.Upstream) (err error) {
// testTLD is the special-use fully-qualified domain name for testing the
// DNS server reachability.
//
// See https://datatracker.ietf.org/doc/html/rfc6761#section-6.2.
const testTLD = "test."
req := &dns.Msg{
MsgHdr: dns.MsgHdr{
Id: dns.Id(),
RecursionDesired: true,
},
Question: []dns.Question{{
Name: testTLD,
Qtype: dns.TypeA,
Qclass: dns.ClassINET,
}},
}
var reply *dns.Msg
reply, err = u.Exchange(req)
if err != nil {
return fmt.Errorf("couldn't communicate with upstream: %w", err)
} else if len(reply.Answer) != 0 {
return errors.Error("wrong response")
}
return nil
}
// checkPrivateUpstreamExc checks if the upstream for resolving private
// addresses exchanges correctly.
//
// TODO(e.burkov): Think about testing the ip6.arpa. as well.
func checkPrivateUpstreamExc(u upstream.Upstream) (err error) {
// inAddrArpaTLD is the special-use fully-qualified domain name for PTR IP
// address resolution.
//
// See https://datatracker.ietf.org/doc/html/rfc1035#section-3.5.
const inAddrArpaTLD = "in-addr.arpa."
req := &dns.Msg{
MsgHdr: dns.MsgHdr{
Id: dns.Id(),
RecursionDesired: true,
},
Question: []dns.Question{{
Name: inAddrArpaTLD,
Qtype: dns.TypePTR,
Qclass: dns.ClassINET,
}},
}
if _, err = u.Exchange(req); err != nil {
return fmt.Errorf("couldn't communicate with upstream: %w", err)
}
return nil
}
// domainSpecificTestError is a wrapper for errors returned by checkDNS to mark
// the tested upstream domain-specific and therefore consider its errors
// non-critical.
//
// TODO(a.garipov): Some common mechanism of distinguishing between errors and
// warnings (non-critical errors) is desired.
type domainSpecificTestError struct {
error
}
// Error implements the [error] interface for domainSpecificTestError.
func (err domainSpecificTestError) Error() (msg string) {
return fmt.Sprintf("WARNING: %s", err.error)
}
// checkDNS parses line, creates DNS upstreams using opts, and checks if the
// upstreams are exchanging correctly. It saves the result into a sync.Map
// where key is an upstream address and value is "OK", if the upstream
// exchanges correctly, or text of the error. It is intended to be used as a
// goroutine.
//
// TODO(s.chzhen): Separate to a different structure/file.
func (s *Server) checkDNS(
line string,
opts *upstream.Options,
check healthCheckFunc,
wg *sync.WaitGroup,
m *sync.Map,
) {
defer wg.Done()
defer log.OnPanic("dnsforward: checking upstreams")
upstreams, domains, err := separateUpstream(line)
if err != nil {
err = fmt.Errorf("wrong upstream format: %w", err)
m.Store(line, err.Error())
return
}
specific := len(domains) > 0
for _, upstreamAddr := range upstreams {
var useDefault bool
useDefault, err = validateUpstream(upstreamAddr, domains)
if err != nil {
err = fmt.Errorf("wrong upstream format: %w", err)
m.Store(upstreamAddr, err.Error())
continue
}
if useDefault {
continue
}
log.Debug("dnsforward: checking if upstream %q works", upstreamAddr)
err = s.checkUpstreamAddr(upstreamAddr, specific, opts, check)
if err != nil {
m.Store(upstreamAddr, err.Error())
} else {
m.Store(upstreamAddr, "OK")
}
}
}
// checkUpstreamAddr creates the DNS upstream using opts and information from
// [s.dnsFilter.EtcHosts]. Checks if the DNS upstream exchanges correctly. It
// returns an error if addr is not valid DNS upstream address or the upstream
// is not exchanging correctly.
func (s *Server) checkUpstreamAddr(
addr string,
specific bool,
opts *upstream.Options,
check healthCheckFunc,
) (err error) {
defer func() {
if err != nil && specific {
err = domainSpecificTestError{error: err}
}
}()
u, err := upstream.AddressToUpstream(addr, &upstream.Options{
Bootstrap: opts.Bootstrap,
Timeout: opts.Timeout,
PreferIPv6: opts.PreferIPv6,
})
if err != nil {
return fmt.Errorf("creating upstream for %q: %w", addr, err)
}
defer func() { err = errors.WithDeferred(err, u.Close()) }()
return check(u)
}
// closeBoots closes all the provided bootstrap servers and logs errors if any.
func closeBoots(boots []*upstream.UpstreamResolver) {
for _, c := range boots {
@ -942,36 +577,11 @@ func (s *Server) handleTestUpstreamDNS(w http.ResponseWriter, r *http.Request) {
}
defer closeBoots(boots)
wg := &sync.WaitGroup{}
m := &sync.Map{}
cv := newUpstreamConfigValidator(req.Upstreams, req.FallbackDNS, req.PrivateUpstreams, opts)
cv.check()
cv.close()
wg.Add(len(req.Upstreams) + len(req.FallbackDNS) + len(req.PrivateUpstreams))
for _, ups := range req.Upstreams {
go s.checkDNS(ups, opts, checkDNSUpstreamExc, wg, m)
}
for _, ups := range req.FallbackDNS {
go s.checkDNS(ups, opts, checkDNSUpstreamExc, wg, m)
}
for _, ups := range req.PrivateUpstreams {
go s.checkDNS(ups, opts, checkPrivateUpstreamExc, wg, m)
}
wg.Wait()
result := map[string]string{}
m.Range(func(k, v any) bool {
// TODO(e.burkov): The upstreams used for both common and private
// resolving should be reported separately.
ups := k.(string)
status := v.(string)
result[ups] = status
return true
})
aghhttp.WriteJSONResponseOK(w, r, result)
aghhttp.WriteJSONResponseOK(w, r, cv.status())
}
// handleCacheClear is the handler for the POST /control/cache_clear HTTP API.

116
internal/dnsforward/http_test.go
View file

@ -363,7 +363,7 @@ func TestValidateUpstreams(t *testing.T) {
set: []string{"123.3.7m"},
}, {
name: "invalid",
wantErr: `bad upstream for domain "[/host.com]tls://dns.adguard.com": ` +
wantErr: `splitting upstream line "[/host.com]tls://dns.adguard.com": ` +
`missing separator`,
set: []string{"[/host.com]tls://dns.adguard.com"},
}, {
@ -389,7 +389,7 @@ func TestValidateUpstreams(t *testing.T) {
},
}, {
name: "bad_domain",
wantErr: `bad upstream for domain "[/!/]8.8.8.8": domain at index 0: ` +
wantErr: `splitting upstream line "[/!/]8.8.8.8": domain at index 0: ` +
`bad domain name "!": bad top-level domain name label "!": ` +
`bad top-level domain name label rune '!'`,
set: []string{"[/!/]8.8.8.8"},
@ -477,25 +477,15 @@ func newLocalUpstreamListener(t *testing.T, port uint16, handler dns.Handler) (r
}
func TestServer_HandleTestUpstreamDNS(t *testing.T) {
goodHandler := dns.HandlerFunc(func(w dns.ResponseWriter, m *dns.Msg) {
hdlr := dns.HandlerFunc(func(w dns.ResponseWriter, m *dns.Msg) {
err := w.WriteMsg(new(dns.Msg).SetReply(m))
require.NoError(testutil.PanicT{}, err)
})
badHandler := dns.HandlerFunc(func(w dns.ResponseWriter, _ *dns.Msg) {
err := w.WriteMsg(new(dns.Msg))
require.NoError(testutil.PanicT{}, err)
})
goodUps := (&url.URL{
ups := (&url.URL{
Scheme: "tcp",
Host: newLocalUpstreamListener(t, 0, goodHandler).String(),
Host: newLocalUpstreamListener(t, 0, hdlr).String(),
}).String()
badUps := (&url.URL{
Scheme: "tcp",
Host: newLocalUpstreamListener(t, 0, badHandler).String(),
}).String()
goodAndBadUps := strings.Join([]string{goodUps, badUps}, " ")
const (
upsTimeout = 100 * time.Millisecond
@ -504,7 +494,7 @@ func TestServer_HandleTestUpstreamDNS(t *testing.T) {
upstreamHost = "custom.localhost"
)
hostsListener := newLocalUpstreamListener(t, 0, goodHandler)
hostsListener := newLocalUpstreamListener(t, 0, hdlr)
hostsUps := (&url.URL{
Scheme: "tcp",
Host: netutil.JoinHostPort(upstreamHost, hostsListener.Port()),
@ -545,43 +535,6 @@ func TestServer_HandleTestUpstreamDNS(t *testing.T) {
wantResp map[string]any
name string
}{{
body: map[string]any{
"upstream_dns": []string{goodUps},
},
wantResp: map[string]any{
goodUps: "OK",
},
name: "success",
}, {
body: map[string]any{
"upstream_dns": []string{badUps},
},
wantResp: map[string]any{
badUps: `couldn't communicate with upstream: exchanging with ` +
badUps + ` over tcp: dns: id mismatch`,
},
name: "broken",
}, {
body: map[string]any{
"upstream_dns": []string{goodUps, badUps},
},
wantResp: map[string]any{
goodUps: "OK",
badUps: `couldn't communicate with upstream: exchanging with ` +
badUps + ` over tcp: dns: id mismatch`,
},
name: "both",
}, {
body: map[string]any{
"upstream_dns": []string{"[/domain.example/]" + badUps},
},
wantResp: map[string]any{
badUps: `WARNING: couldn't communicate ` +
`with upstream: exchanging with ` + badUps + ` over tcp: ` +
`dns: id mismatch`,
},
name: "domain_specific_error",
}, {
body: map[string]any{
"upstream_dns": []string{hostsUps},
},
@ -591,63 +544,12 @@ func TestServer_HandleTestUpstreamDNS(t *testing.T) {
name: "etc_hosts",
}, {
body: map[string]any{
"fallback_dns": []string{goodUps},
"upstream_dns": []string{ups, "#this.is.comment"},
},
wantResp: map[string]any{
goodUps: "OK",
ups: "OK",
},
name: "fallback_success",
}, {
body: map[string]any{
"fallback_dns": []string{badUps},
},
wantResp: map[string]any{
badUps: `couldn't communicate with upstream: exchanging with ` +
badUps + ` over tcp: dns: id mismatch`,
},
name: "fallback_broken",
}, {
body: map[string]any{
"fallback_dns": []string{goodUps, "#this.is.comment"},
},
wantResp: map[string]any{
goodUps: "OK",
},
name: "fallback_comment_mix",
}, {
body: map[string]any{
"upstream_dns": []string{"[/domain.example/]" + goodUps + " " + badUps},
},
wantResp: map[string]any{
goodUps: "OK",
badUps: `WARNING: couldn't communicate ` +
`with upstream: exchanging with ` + badUps + ` over tcp: ` +
`dns: id mismatch`,
},
name: "multiple_domain_specific_upstreams",
}, {
body: map[string]any{
"upstream_dns": []string{"[/domain.example/]/]1.2.3.4"},
},
wantResp: map[string]any{
"[/domain.example/]/]1.2.3.4": `wrong upstream format: ` +
`bad upstream for domain "[/domain.example/]/]1.2.3.4": ` +
`duplicated separator`,
},
name: "bad_specification",
}, {
body: map[string]any{
"upstream_dns": []string{"[/domain.example/]" + goodAndBadUps},
"fallback_dns": []string{"[/domain.example/]" + goodAndBadUps},
"private_upstream": []string{"[/domain.example/]" + goodAndBadUps},
},
wantResp: map[string]any{
goodUps: "OK",
badUps: `WARNING: couldn't communicate ` +
`with upstream: exchanging with ` + badUps + ` over tcp: ` +
`dns: id mismatch`,
},
name: "all_different",
name: "comment_mix",
}}
for _, tc := range testCases {

209
internal/dnsforward/upstreams.go
View file

@ -2,14 +2,43 @@ package dnsforward
import (
"fmt"
"net"
"net/netip"
"os"
"strings"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
"github.com/AdguardTeam/dnsproxy/proxy"
"github.com/AdguardTeam/dnsproxy/upstream"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/golibs/netutil"
"github.com/AdguardTeam/golibs/stringutil"
"golang.org/x/exp/maps"
"golang.org/x/exp/slices"
)
const (
// errNotDomainSpecific is returned when the upstream should be
// domain-specific, but isn't.
errNotDomainSpecific errors.Error = "not a domain-specific upstream"
// errMissingSeparator is returned when the domain-specific part of the
// upstream configuration line isn't closed.
errMissingSeparator errors.Error = "missing separator"
// errDupSeparator is returned when the domain-specific part of the upstream
// configuration line contains more than one ending separator.
errDupSeparator errors.Error = "duplicated separator"
// errNoDefaultUpstreams is returned when there are no default upstreams
// specified in the upstream configuration.
errNoDefaultUpstreams errors.Error = "no default upstreams specified"
// errWrongResponse is returned when the checked upstream replies in an
// unexpected way.
errWrongResponse errors.Error = "wrong response"
)
// loadUpstreams parses upstream DNS servers from the configured file or from
@ -158,3 +187,183 @@ func (s *Server) createBootstrap(
return r, boots, nil
}
// IsCommentOrEmpty returns true if s starts with a "#" character or is empty.
// This function is useful for filtering out non-upstream lines from upstream
// configs.
func IsCommentOrEmpty(s string) (ok bool) {
return len(s) == 0 || s[0] == '#'
}
// newUpstreamConfig validates upstreams and returns an appropriate upstream
// configuration or nil if it can't be built.
//
// TODO(e.burkov): Perhaps proxy.ParseUpstreamsConfig should validate upstreams
// slice already so that this function may be considered useless.
func newUpstreamConfig(upstreams []string) (conf *proxy.UpstreamConfig, err error) {
// No need to validate comments and empty lines.
upstreams = stringutil.FilterOut(upstreams, IsCommentOrEmpty)
if len(upstreams) == 0 {
// Consider this case valid since it means the default server should be
// used.
return nil, nil
}
err = validateUpstreamConfig(upstreams)
if err != nil {
// Don't wrap the error since it's informative enough as is.
return nil, err
}
conf, err = proxy.ParseUpstreamsConfig(
upstreams,
&upstream.Options{
Bootstrap: net.DefaultResolver,
Timeout: DefaultTimeout,
},
)
if err != nil {
// Don't wrap the error since it's informative enough as is.
return nil, err
} else if len(conf.Upstreams) == 0 {
return nil, errNoDefaultUpstreams
}
return conf, nil
}
// validateUpstreamConfig validates each upstream from the upstream
// configuration and returns an error if any upstream is invalid.
//
// TODO(e.burkov): Merge with [upstreamConfigValidator] somehow.
func validateUpstreamConfig(conf []string) (err error) {
for _, u := range conf {
var ups []string
var isSpecific bool
ups, isSpecific, err = splitUpstreamLine(u)
if err != nil {
// Don't wrap the error since it's informative enough as is.
return err
}
for _, addr := range ups {
_, err = validateUpstream(addr, isSpecific)
if err != nil {
return fmt.Errorf("validating upstream %q: %w", addr, err)
}
}
}
return nil
}
// ValidateUpstreams validates each upstream and returns an error if any
// upstream is invalid or if there are no default upstreams specified.
//
// TODO(e.burkov): Merge with [upstreamConfigValidator] somehow.
func ValidateUpstreams(upstreams []string) (err error) {
_, err = newUpstreamConfig(upstreams)
return err
}
// ValidateUpstreamsPrivate validates each upstream and returns an error if any
// upstream is invalid or if there are no default upstreams specified. It also
// checks each domain of domain-specific upstreams for being ARPA pointing to
// a locally-served network. privateNets must not be nil.
func ValidateUpstreamsPrivate(upstreams []string, privateNets netutil.SubnetSet) (err error) {
conf, err := newUpstreamConfig(upstreams)
if err != nil {
return fmt.Errorf("creating config: %w", err)
}
if conf == nil {
return nil
}
keys := maps.Keys(conf.DomainReservedUpstreams)
slices.Sort(keys)
var errs []error
for _, domain := range keys {
var subnet netip.Prefix
subnet, err = extractARPASubnet(domain)
if err != nil {
errs = append(errs, err)
continue
}
if !privateNets.Contains(subnet.Addr().AsSlice()) {
errs = append(
errs,
fmt.Errorf("arpa domain %q should point to a locally-served network", domain),
)
}
}
return errors.Annotate(errors.Join(errs...), "checking domain-specific upstreams: %w")
}
// protocols are the supported URL schemes for upstreams.
var protocols = []string{"h3", "https", "quic", "sdns", "tcp", "tls", "udp"}
// validateUpstream returns an error if u alongside with domains is not a valid
// upstream configuration. useDefault is true if the upstream is
// domain-specific and is configured to point at the default upstream server
// which is validated separately. The upstream is considered domain-specific
// only if domains is at least not nil.
func validateUpstream(u string, isSpecific bool) (useDefault bool, err error) {
// The special server address '#' means that default server must be used.
if useDefault = u == "#" && isSpecific; useDefault {
return useDefault, nil
}
// Check if the upstream has a valid protocol prefix.
//
// TODO(e.burkov): Validate the domain name.
if proto, _, ok := strings.Cut(u, "://"); ok {
if !slices.Contains(protocols, proto) {
return false, fmt.Errorf("bad protocol %q", proto)
}
} else if _, err = netip.ParseAddr(u); err == nil {
return false, nil
} else if _, err = netip.ParseAddrPort(u); err == nil {
return false, nil
}
return false, err
}
// splitUpstreamLine returns the upstreams and the specified domains. domains
// is nil when the upstream is not domains-specific. Otherwise it may also be
// empty.
func splitUpstreamLine(upstreamStr string) (upstreams []string, isSpecific bool, err error) {
if !strings.HasPrefix(upstreamStr, "[/") {
return []string{upstreamStr}, false, nil
}
defer func() { err = errors.Annotate(err, "splitting upstream line %q: %w", upstreamStr) }()
doms, ups, found := strings.Cut(upstreamStr[2:], "/]")
if !found {
return nil, false, errMissingSeparator
} else if strings.Contains(ups, "/]") {
return nil, false, errDupSeparator
}
for i, host := range strings.Split(doms, "/") {
if host == "" {
continue
}
err = netutil.ValidateDomainName(strings.TrimPrefix(host, "*."))
if err != nil {
return nil, false, fmt.Errorf("domain at index %d: %w", i, err)
}
isSpecific = true
}
return strings.Fields(ups), isSpecific, nil
}

209
internal/dnsforward/upstreams_internal_test.go Normal file
View file

@ -0,0 +1,209 @@
package dnsforward
import (
"net"
"net/url"
"strings"
"sync/atomic"
"testing"
"time"
"github.com/AdguardTeam/dnsproxy/upstream"
"github.com/AdguardTeam/golibs/testutil"
"github.com/miekg/dns"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
func TestUpstreamConfigValidator(t *testing.T) {
goodHandler := dns.HandlerFunc(func(w dns.ResponseWriter, m *dns.Msg) {
err := w.WriteMsg(new(dns.Msg).SetReply(m))
require.NoError(testutil.PanicT{}, err)
})
badHandler := dns.HandlerFunc(func(w dns.ResponseWriter, _ *dns.Msg) {
err := w.WriteMsg(new(dns.Msg))
require.NoError(testutil.PanicT{}, err)
})
goodUps := (&url.URL{
Scheme: "tcp",
Host: newLocalUpstreamListener(t, 0, goodHandler).String(),
}).String()
badUps := (&url.URL{
Scheme: "tcp",
Host: newLocalUpstreamListener(t, 0, badHandler).String(),
}).String()
goodAndBadUps := strings.Join([]string{goodUps, badUps}, " ")
// upsTimeout restricts the checking process to prevent the test from
// hanging.
const upsTimeout = 100 * time.Millisecond
testCases := []struct {
want map[string]string
name string
general []string
fallback []string
private []string
}{{
name: "success",
general: []string{goodUps},
want: map[string]string{
goodUps: "OK",
},
}, {
name: "broken",
general: []string{badUps},
want: map[string]string{
badUps: `couldn't communicate with upstream: exchanging with ` +
badUps + ` over tcp: dns: id mismatch`,
},
}, {
name: "both",
general: []string{goodUps, badUps, goodUps},
want: map[string]string{
goodUps: "OK",
badUps: `couldn't communicate with upstream: exchanging with ` +
badUps + ` over tcp: dns: id mismatch`,
},
}, {
name: "domain_specific_error",
general: []string{"[/domain.example/]" + badUps},
want: map[string]string{
badUps: `WARNING: couldn't communicate ` +
`with upstream: exchanging with ` + badUps + ` over tcp: ` +
`dns: id mismatch`,
},
}, {
name: "fallback_success",
fallback: []string{goodUps},
want: map[string]string{
goodUps: "OK",
},
}, {
name: "fallback_broken",
fallback: []string{badUps},
want: map[string]string{
badUps: `couldn't communicate with upstream: exchanging with ` +
badUps + ` over tcp: dns: id mismatch`,
},
}, {
name: "multiple_domain_specific_upstreams",
general: []string{"[/domain.example/]" + goodAndBadUps},
want: map[string]string{
goodUps: "OK",
badUps: `WARNING: couldn't communicate ` +
`with upstream: exchanging with ` + badUps + ` over tcp: ` +
`dns: id mismatch`,
},
}, {
name: "bad_specification",
general: []string{"[/domain.example/]/]1.2.3.4"},
want: map[string]string{
"[/domain.example/]/]1.2.3.4": `splitting upstream line ` +
`"[/domain.example/]/]1.2.3.4": duplicated separator`,
},
}, {
name: "all_different",
general: []string{"[/domain.example/]" + goodAndBadUps},
fallback: []string{"[/domain.example/]" + goodAndBadUps},
private: []string{"[/domain.example/]" + goodAndBadUps},
want: map[string]string{
goodUps: "OK",
badUps: `WARNING: couldn't communicate ` +
`with upstream: exchanging with ` + badUps + ` over tcp: ` +
`dns: id mismatch`,
},
}, {
name: "bad_specific_domains",
general: []string{"[/example/]/]" + goodUps},
fallback: []string{"[/example/" + goodUps},
private: []string{"[/example//bad.123/]" + goodUps},
want: map[string]string{
`[/example/]/]` + goodUps: `splitting upstream line ` +
`"[/example/]/]` + goodUps + `": duplicated separator`,
`[/example/` + goodUps: `splitting upstream line ` +
`"[/example/` + goodUps + `": missing separator`,
`[/example//bad.123/]` + goodUps: `splitting upstream line ` +
`"[/example//bad.123/]` + goodUps + `": domain at index 2: ` +
`bad domain name "bad.123": ` +
`bad top-level domain name label "123": all octets are numeric`,
},
}, {
name: "non-specific_default",
general: []string{
"#",
"[/example/]#",
},
want: map[string]string{
"#": "not a domain-specific upstream",
},
}, {
name: "bad_proto",
general: []string{
"bad://1.2.3.4",
},
want: map[string]string{
"bad://1.2.3.4": `bad protocol "bad"`,
},
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
cv := newUpstreamConfigValidator(tc.general, tc.fallback, tc.private, &upstream.Options{
Timeout: upsTimeout,
Bootstrap: net.DefaultResolver,
})
cv.check()
cv.close()
assert.Equal(t, tc.want, cv.status())
})
}
}
func TestUpstreamConfigValidator_Check_once(t *testing.T) {
reqs := atomic.Int32{}
reset := func() { reqs.Store(0) }
hdlr := dns.HandlerFunc(func(w dns.ResponseWriter, m *dns.Msg) {
err := w.WriteMsg(new(dns.Msg).SetReply(m))
require.NoError(testutil.PanicT{}, err)
reqs.Add(1)
})
addr := (&url.URL{
Scheme: "tcp",
Host: newLocalUpstreamListener(t, 0, hdlr).String(),
}).String()
twoAddrs := strings.Join([]string{addr, addr}, " ")
testCases := []struct {
name string
ups []string
}{{
name: "common",
ups: []string{addr, addr, addr},
}, {
name: "domain-specific",
ups: []string{"[/one.example/]" + addr, "[/two.example/]" + twoAddrs},
}, {
name: "both",
ups: []string{addr, "[/one.example/]" + addr, addr, "[/two.example/]" + twoAddrs},
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
t.Cleanup(reset)
cv := newUpstreamConfigValidator(tc.ups, nil, nil, &upstream.Options{
Timeout: 100 * time.Millisecond,
})
cv.check()
cv.close()
assert.Equal(t, int32(1), reqs.Load())
})
}
}