fix: panic due to goroutine setting returned error (daeuniverse#748)

common/netutils/dns.go

@@ -140,6 +140,25 @@ func ResolveNS(ctx context.Context, d netproxy.Dialer, dns netip.AddrPort, host
 	return records, nil
 }
 
+func ResolveSOA(ctx context.Context, d netproxy.Dialer, dns netip.AddrPort, host string, network string) (records []string, err error) {
+	typ := dnsmessage.TypeSOA
+	resources, err := resolve(ctx, d, dns, host, typ, network)
+	if err != nil {
+		return nil, err
+	}
+	for _, ans := range resources {
+		if ans.Header().Rrtype != typ {
+			continue
+		}
+		ns, ok := ans.(*dnsmessage.SOA)
+		if !ok {
+			return nil, ErrBadDnsAns
+		}
+		records = append(records, ns.Ns)
+	}
+	return records, nil
+}
+
 func resolve(ctx context.Context, d netproxy.Dialer, dns netip.AddrPort, host string, typ uint16, network string) (ans []dnsmessage.RR, err error) {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()

common/netutils/ip46.go

@@ -8,7 +8,6 @@ package netutils
 import (
 	"context"
 	"errors"
-	"fmt"
 	"net/netip"
 	"sync"
 
@@ -22,24 +21,22 @@ type Ip46 struct {
 	Ip6 netip.Addr
 }
 
-func ResolveIp46(ctx context.Context, dialer netproxy.Dialer, dns netip.AddrPort, host string, network string, race bool) (ipv46 *Ip46, err error) {
+func ResolveIp46(ctx context.Context, dialer netproxy.Dialer, dns netip.AddrPort, host string, network string, race bool) (ipv46 *Ip46, err4, err6 error) {
 	var log *logrus.Logger
 	if _log := ctx.Value("logger"); _log != nil {
 		log = _log.(*logrus.Logger)
 		defer func() {
-			if err == nil {
-				log.Tracef("ResolveIp46 %v using %v: A(%v) AAAA(%v)", host, systemDns, ipv46.Ip4, ipv46.Ip6)
-			} else {
-				log.Tracef("ResolveIp46 %v using %v: %v", host, systemDns, err)
-			}
+			log.WithField("err4", err4).
+				WithField("err6", err6).
+				Tracef("ResolveIp46 %v using %v: A(%v) AAAA(%v)", host, systemDns, ipv46.Ip4, ipv46.Ip6)
 		}()
 	}
 	var wg sync.WaitGroup
 	wg.Add(2)
-	var err4, err6 error
 	var addrs4, addrs6 []netip.Addr
 	ctx4, cancel4 := context.WithCancel(ctx)
 	ctx6, cancel6 := context.WithCancel(ctx)
+	var _err4, _err6 error
 	go func() {
 		defer func() {
 			wg.Done()
@@ -50,13 +47,10 @@ func ResolveIp46(ctx context.Context, dialer netproxy.Dialer, dns netip.AddrPort
 		}()
 		var e error
 		addrs4, e = ResolveNetip(ctx4, dialer, dns, host, dnsmessage.TypeA, network)
-		if err != nil && !errors.Is(e, context.Canceled) {
-			err4 = e
+		if e != nil && !errors.Is(e, context.Canceled) {
+			_err4 = e
 			return
 		}
-		if len(addrs4) == 0 {
-			addrs4 = []netip.Addr{{}}
-		}
 	}()
 	go func() {
 		defer func() {
@@ -68,27 +62,18 @@ func ResolveIp46(ctx context.Context, dialer netproxy.Dialer, dns netip.AddrPort
 		}()
 		var e error
 		addrs6, e = ResolveNetip(ctx6, dialer, dns, host, dnsmessage.TypeAAAA, network)
-		if err != nil && !errors.Is(e, context.Canceled) {
+		if e != nil && !errors.Is(e, context.Canceled) {
 			err6 = e
 			return
 		}
-		if len(addrs6) == 0 {
-			addrs6 = []netip.Addr{{}}
-		}
 	}()
 	wg.Wait()
-	if err4 != nil || err6 != nil {
-		if err4 != nil && err6 != nil {
-			return nil, fmt.Errorf("%w: %v", err4, err6)
-		}
-		if err4 != nil {
-			return nil, err4
-		} else {
-			return nil, err6
-		}
+	ipv46 = &Ip46{}
+	if len(addrs4) != 0 {
+		ipv46.Ip4 = addrs4[0]
+	}
+	if len(addrs6) != 0 {
+		ipv46.Ip6 = addrs6[0]
 	}
-	return &Ip46{
-		Ip4: addrs4[0],
-		Ip6: addrs6[0],
-	}, nil
+	return ipv46, _err4, _err6
 }

common/netutils/ip46_test.go

@@ -17,11 +17,12 @@ import (
 func TestResolveIp46(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
-	ip46, err := ResolveIp46(ctx, direct.SymmetricDirect, netip.MustParseAddrPort("223.5.5.5:53"), "www.apple.com", "udp", false)
-	if err != nil {
-		t.Fatal(err)
+	ip46, err4, err6 := ResolveIp46(ctx, direct.SymmetricDirect, netip.MustParseAddrPort("223.5.5.5:53"), "ipv6.google.com", "udp", false)
+	if err4 != nil || err6 != nil {
+		t.Fatal(err4, err6)
 	}
 	if !ip46.Ip4.IsValid() && !ip46.Ip6.IsValid() {
 		t.Fatal("No record")
 	}
+	t.Log(ip46)
 }

component/dns/upstream.go

@@ -112,10 +112,7 @@ func NewUpstream(ctx context.Context, upstream *url.URL, resolverNetwork string)
 		}
 	}()
 
-	ip46, err := netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, hostname, resolverNetwork, false)
-	if err != nil {
-		return nil, fmt.Errorf("failed to resolve dns_upstream: %w", err)
-	}
+	ip46, _, _ := netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, hostname, resolverNetwork, false)
 	if !ip46.Ip4.IsValid() && !ip46.Ip6.IsValid() {
 		return nil, fmt.Errorf("dns_upstream %v has no record", upstream.String())
 	}

component/outbound/dialer/connectivity_check.go

@@ -160,9 +160,9 @@ func ParseTcpCheckOption(ctx context.Context, rawURL []string, method string, re
 	if len(rawURL) > 1 {
 		ip46 = parseIp46FromList(rawURL[1:])
 	} else {
-		ip46, err = netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, u.Hostname(), resolverNetwork, false)
-		if err != nil {
-			return nil, err
+		ip46, _, _ = netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, u.Hostname(), resolverNetwork, false)
+		if !ip46.Ip4.IsValid() && !ip46.Ip6.IsValid() {
+			return nil, fmt.Errorf("ResolveIp46: no valid ip for %v", u.Hostname())
 		}
 	}
 	return &TcpCheckOption{
@@ -205,9 +205,9 @@ func ParseCheckDnsOption(ctx context.Context, dnsHostPort []string, resolverNetw
 	if len(dnsHostPort) > 1 {
 		ip46 = parseIp46FromList(dnsHostPort[1:])
 	} else {
-		ip46, err = netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, host, resolverNetwork, false)
-		if err != nil {
-			return nil, err
+		ip46, _, _ = netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, host, resolverNetwork, false)
+		if !ip46.Ip4.IsValid() && !ip46.Ip6.IsValid() {
+			return nil, fmt.Errorf("ResolveIp46: no valid ip for %v", host)
 		}
 	}
 	return &CheckDnsOption{

component/sniffing/sniffer.go

@@ -107,7 +107,7 @@ func (s *Sniffer) SniffTcp() (d string, err error) {
 		if s.stream {
 			go func() {
 				// Read once.
-				_, err = s.buf.ReadFromOnce(s.r)
+				_, err := s.buf.ReadFromOnce(s.r)
 				if err != nil {
 					s.dataError = err
 				}

control/control_plane.go

@@ -662,7 +662,7 @@ func (c *ControlPlane) ChooseDialTarget(outbound consts.OutboundIndex, dst netip
 					// TODO: use DNS controller and re-route by control plane.
 					systemDns, err := netutils.SystemDns()
 					if err == nil {
-						if ip46, err := netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, domain, common.MagicNetwork("udp", c.soMarkFromDae, c.mptcp), true); err == nil && (ip46.Ip4.IsValid() || ip46.Ip6.IsValid()) {
+						if ip46, _, _ := netutils.ResolveIp46(ctx, direct.SymmetricDirect, systemDns, domain, common.MagicNetwork("udp", c.soMarkFromDae, c.mptcp), true); ip46.Ip4.IsValid() || ip46.Ip6.IsValid() {
 							// Has A/AAAA records. It is a real domain.
 							dialMode = consts.DialMode_Domain
 							// Add it to real-domain set.

control/dns.go

@@ -317,7 +317,7 @@ func (d *DoUDP) ForwardDNS(ctx context.Context, data []byte) (*dnsmessage.Msg, e
 	go func() {
 		// Send DNS request every seconds.
 		for {
-			_, err = conn.Write(data)
+			_, _ = conn.Write(data)
 			// if err != nil {
 			// 	if c.log.IsLevelEnabled(logrus.DebugLevel) {
 			// 		c.log.WithFields(logrus.Fields{