sing-box/route/router_dns.go
2022-11-21 13:18:04 +08:00

123 lines
3.8 KiB
Go

package route
import (
"context"
"net/netip"
"strings"
"github.com/sagernet/sing-box/adapter"
C "github.com/sagernet/sing-box/constant"
"github.com/sagernet/sing-box/log"
"github.com/sagernet/sing-dns"
E "github.com/sagernet/sing/common/exceptions"
F "github.com/sagernet/sing/common/format"
mDNS "github.com/miekg/dns"
)
func (r *Router) matchDNS(ctx context.Context) (context.Context, dns.Transport, dns.DomainStrategy) {
metadata := adapter.ContextFrom(ctx)
if metadata == nil {
panic("no context")
}
for i, rule := range r.dnsRules {
if rule.Match(metadata) {
if rule.DisableCache() {
ctx = dns.ContextWithDisableCache(ctx, true)
}
detour := rule.Outbound()
r.dnsLogger.DebugContext(ctx, "match[", i, "] ", rule.String(), " => ", detour)
if transport, loaded := r.transportMap[detour]; loaded {
if domainStrategy, dsLoaded := r.transportDomainStrategy[transport]; dsLoaded {
return ctx, transport, domainStrategy
} else {
return ctx, transport, r.defaultDomainStrategy
}
}
r.dnsLogger.ErrorContext(ctx, "transport not found: ", detour)
}
}
if domainStrategy, dsLoaded := r.transportDomainStrategy[r.defaultTransport]; dsLoaded {
return ctx, r.defaultTransport, domainStrategy
} else {
return ctx, r.defaultTransport, r.defaultDomainStrategy
}
}
func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, error) {
if len(message.Question) > 0 {
r.dnsLogger.DebugContext(ctx, "exchange ", formatQuestion(message.Question[0].String()))
}
ctx, metadata := adapter.AppendContext(ctx)
if len(message.Question) > 0 {
switch message.Question[0].Qtype {
case mDNS.TypeA:
metadata.IPVersion = 4
case mDNS.TypeAAAA:
metadata.IPVersion = 6
}
metadata.Domain = fqdnToDomain(message.Question[0].Name)
}
ctx, transport, strategy := r.matchDNS(ctx)
ctx, cancel := context.WithTimeout(ctx, C.DNSTimeout)
defer cancel()
response, err := r.dnsClient.Exchange(ctx, transport, message, strategy)
if err != nil && len(message.Question) > 0 {
r.dnsLogger.ErrorContext(ctx, E.Cause(err, "exchange failed for ", formatQuestion(message.Question[0].String())))
}
if len(message.Question) > 0 && response != nil {
LogDNSAnswers(r.dnsLogger, ctx, message.Question[0].Name, response.Answer)
}
return response, err
}
func (r *Router) Lookup(ctx context.Context, domain string, strategy dns.DomainStrategy) ([]netip.Addr, error) {
r.dnsLogger.DebugContext(ctx, "lookup domain ", domain)
ctx, metadata := adapter.AppendContext(ctx)
metadata.Domain = domain
ctx, transport, transportStrategy := r.matchDNS(ctx)
if strategy == dns.DomainStrategyAsIS {
strategy = transportStrategy
}
ctx, cancel := context.WithTimeout(ctx, C.DNSTimeout)
defer cancel()
addrs, err := r.dnsClient.Lookup(ctx, transport, domain, strategy)
if len(addrs) > 0 {
r.dnsLogger.InfoContext(ctx, "lookup succeed for ", domain, ": ", strings.Join(F.MapToString(addrs), " "))
} else {
r.dnsLogger.ErrorContext(ctx, E.Cause(err, "lookup failed for ", domain))
if err == nil {
err = dns.RCodeNameError
}
}
return addrs, err
}
func (r *Router) LookupDefault(ctx context.Context, domain string) ([]netip.Addr, error) {
return r.Lookup(ctx, domain, dns.DomainStrategyAsIS)
}
func LogDNSAnswers(logger log.ContextLogger, ctx context.Context, domain string, answers []mDNS.RR) {
for _, answer := range answers {
logger.InfoContext(ctx, "exchanged ", domain, " ", mDNS.Type(answer.Header().Rrtype).String(), " ", formatQuestion(answer.String()))
}
}
func fqdnToDomain(fqdn string) string {
if mDNS.IsFqdn(fqdn) {
return fqdn[:len(fqdn)-1]
}
return fqdn
}
func formatQuestion(string string) string {
if strings.HasPrefix(string, ";") {
string = string[1:]
}
string = strings.ReplaceAll(string, "\t", " ")
for strings.Contains(string, " ") {
string = strings.ReplaceAll(string, " ", " ")
}
return string
}