AdGuardHome/internal/dnsforward/upstreams.go

172 lines
5.0 KiB
Go

package dnsforward
import (
"fmt"
"slices"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
"github.com/AdguardTeam/dnsproxy/proxy"
"github.com/AdguardTeam/dnsproxy/upstream"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/golibs/netutil"
"github.com/AdguardTeam/golibs/stringutil"
)
// newBootstrap returns a bootstrap resolver based on the configuration of s.
// boots are the upstream resolvers that should be closed after use. r is the
// actual bootstrap resolver, which may include the system hosts.
//
// TODO(e.burkov): This function currently returns a resolver and a slice of
// the upstream resolvers, which are essentially the same. boots are returned
// for being able to close them afterwards, but it introduces an implicit
// contract that r could only be used before that. Anyway, this code should
// improve when the [proxy.UpstreamConfig] will become an [upstream.Resolver]
// and be used here.
func newBootstrap(
addrs []string,
etcHosts upstream.Resolver,
opts *upstream.Options,
) (r upstream.Resolver, boots []*upstream.UpstreamResolver, err error) {
if len(addrs) == 0 {
addrs = defaultBootstrap
}
boots, err = aghnet.ParseBootstraps(addrs, opts)
if err != nil {
// Don't wrap the error, since it's informative enough as is.
return nil, nil, err
}
var parallel upstream.ParallelResolver
for _, b := range boots {
parallel = append(parallel, upstream.NewCachingResolver(b))
}
if etcHosts != nil {
r = upstream.ConsequentResolver{etcHosts, parallel}
} else {
r = parallel
}
return r, boots, nil
}
// newUpstreamConfig returns the upstream configuration based on upstreams. If
// upstreams slice specifies no default upstreams, defaultUpstreams are used to
// create upstreams with no domain specifications. opts are used when creating
// upstream configuration.
func newUpstreamConfig(
upstreams []string,
defaultUpstreams []string,
opts *upstream.Options,
) (uc *proxy.UpstreamConfig, err error) {
uc, err = proxy.ParseUpstreamsConfig(upstreams, opts)
if err != nil {
return uc, fmt.Errorf("parsing upstreams: %w", err)
}
if len(uc.Upstreams) == 0 && len(defaultUpstreams) > 0 {
log.Info("dnsforward: warning: no default upstreams specified, using %v", defaultUpstreams)
var defaultUpstreamConfig *proxy.UpstreamConfig
defaultUpstreamConfig, err = proxy.ParseUpstreamsConfig(defaultUpstreams, opts)
if err != nil {
return uc, fmt.Errorf("parsing default upstreams: %w", err)
}
uc.Upstreams = defaultUpstreamConfig.Upstreams
}
return uc, nil
}
// newPrivateConfig creates an upstream configuration for resolving PTR records
// for local addresses. The configuration is built either from the provided
// addresses or from the system resolvers. unwanted filters the resulting
// upstream configuration.
func newPrivateConfig(
addrs []string,
unwanted addrPortSet,
sysResolvers SystemResolvers,
privateNets netutil.SubnetSet,
opts *upstream.Options,
) (uc *proxy.UpstreamConfig, err error) {
confNeedsFiltering := len(addrs) > 0
if confNeedsFiltering {
addrs = stringutil.FilterOut(addrs, IsCommentOrEmpty)
} else {
sysResolvers := slices.DeleteFunc(slices.Clone(sysResolvers.Addrs()), unwanted.Has)
addrs = make([]string, 0, len(sysResolvers))
for _, r := range sysResolvers {
addrs = append(addrs, r.String())
}
}
log.Debug("dnsforward: private-use upstreams: %v", addrs)
uc, err = proxy.ParseUpstreamsConfig(addrs, opts)
if err != nil {
return uc, fmt.Errorf("preparing private upstreams: %w", err)
}
if confNeedsFiltering {
err = filterOutAddrs(uc, unwanted)
if err != nil {
return uc, fmt.Errorf("filtering private upstreams: %w", err)
}
}
// Prevalidate the config to catch the exact error before creating proxy.
// See TODO on [PrivateRDNSError].
err = proxy.ValidatePrivateConfig(uc, privateNets)
if err != nil {
return uc, &PrivateRDNSError{err: err}
}
return uc, nil
}
// UpstreamHTTPVersions returns the HTTP versions for upstream configuration
// depending on configuration.
func UpstreamHTTPVersions(http3 bool) (v []upstream.HTTPVersion) {
if !http3 {
return upstream.DefaultHTTPVersions
}
return []upstream.HTTPVersion{
upstream.HTTPVersion3,
upstream.HTTPVersion2,
upstream.HTTPVersion11,
}
}
// setProxyUpstreamMode sets the upstream mode and related settings in conf
// based on provided parameters.
func setProxyUpstreamMode(
conf *proxy.Config,
upstreamMode UpstreamMode,
fastestTimeout time.Duration,
) (err error) {
switch upstreamMode {
case UpstreamModeParallel:
conf.UpstreamMode = proxy.UModeParallel
case UpstreamModeFastestAddr:
conf.UpstreamMode = proxy.UModeFastestAddr
conf.FastestPingTimeout = fastestTimeout
case UpstreamModeLoadBalance:
conf.UpstreamMode = proxy.UModeLoadBalance
default:
return fmt.Errorf("unexpected value %q", upstreamMode)
}
return 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] == '#'
}