safing-portmaster/resolver/resolver-env.go
2020-07-15 08:53:55 +02:00

95 lines
2.2 KiB
Go

package resolver
import (
"context"
"fmt"
"net"
"github.com/miekg/dns"
"github.com/safing/portbase/log"
"github.com/safing/portmaster/netenv"
"github.com/safing/portmaster/network/netutils"
)
var (
envResolver = &Resolver{
Server: ServerSourceEnv,
ServerType: ServerTypeEnv,
ServerIPScope: netutils.SiteLocal,
Source: ServerSourceEnv,
Conn: &envResolverConn{},
}
)
type envResolverConn struct{}
func (er *envResolverConn) Query(ctx context.Context, q *Query) (*RRCache, error) {
// prepping
portal := netenv.GetCaptivePortal()
// check for matching name
switch q.FQDN {
case netenv.SpecialCaptivePortalDomain:
if portal.IP != nil {
rr, err := portal.IPasRR()
if err != nil {
log.Warningf("nameserver: failed to create captive portal response to %s: %s", q.FQDN, err)
return nil, ErrNotFound
}
return er.makeRRCache(q, []dns.RR{rr}), nil
}
return nil, ErrNotFound
case "router.local.":
routers := netenv.Gateways()
if len(routers) == 0 {
return nil, ErrNotFound
}
records, err := ipsToRRs(q.FQDN, routers)
if err != nil {
log.Warningf("nameserver: failed to create gateway response to %s: %s", q.FQDN, err)
return nil, ErrNotFound
}
return er.makeRRCache(q, records), nil
}
// no match
return nil, ErrContinue // continue with next resolver
}
func (er *envResolverConn) makeRRCache(q *Query, answers []dns.RR) *RRCache {
q.NoCaching = true // disable caching, as the env always has the data available and more up to date.
return &RRCache{
Domain: q.FQDN,
Question: q.QType,
Answer: answers,
Server: envResolver.Server,
ServerScope: envResolver.ServerIPScope,
}
}
func (er *envResolverConn) ReportFailure() {}
func (er *envResolverConn) IsFailing() bool {
return false
}
func ipsToRRs(domain string, ips []net.IP) ([]dns.RR, error) {
var records []dns.RR
var rr dns.RR
var err error
for _, ip := range ips {
if ip.To4() != nil {
rr, err = dns.NewRR(domain + " 17 IN A " + ip.String())
} else {
rr, err = dns.NewRR(domain + " 17 IN AAAA " + ip.String())
}
if err != nil {
return nil, fmt.Errorf("failed to create record for %s: %w", ip, err)
}
records = append(records, rr)
}
return records, nil
}