[netstack] Implement IP(V6)_RECVERR socket option.

PiperOrigin-RevId: 348055514

pkg/sentry/socket/hostinet/socket.go

@@ -331,12 +331,12 @@ func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr
 	switch level {
 	case linux.SOL_IP:
 		switch name {
-		case linux.IP_TOS, linux.IP_RECVTOS, linux.IP_PKTINFO, linux.IP_RECVORIGDSTADDR:
+		case linux.IP_TOS, linux.IP_RECVTOS, linux.IP_PKTINFO, linux.IP_RECVORIGDSTADDR, linux.IP_RECVERR:
 			optlen = sizeofInt32
 		}
 	case linux.SOL_IPV6:
 		switch name {
-		case linux.IPV6_TCLASS, linux.IPV6_RECVTCLASS, linux.IPV6_V6ONLY, linux.IPV6_RECVORIGDSTADDR:
+		case linux.IPV6_TCLASS, linux.IPV6_RECVTCLASS, linux.IPV6_RECVERR, linux.IPV6_V6ONLY, linux.IPV6_RECVORIGDSTADDR:
 			optlen = sizeofInt32
 		}
 	case linux.SOL_SOCKET:
@@ -377,14 +377,14 @@ func (s *socketOpsCommon) SetSockOpt(t *kernel.Task, level int, name int, opt []
 	switch level {
 	case linux.SOL_IP:
 		switch name {
-		case linux.IP_TOS, linux.IP_RECVTOS, linux.IP_RECVORIGDSTADDR:
+		case linux.IP_TOS, linux.IP_RECVTOS, linux.IP_RECVORIGDSTADDR, linux.IP_RECVERR:
 			optlen = sizeofInt32
 		case linux.IP_PKTINFO:
 			optlen = linux.SizeOfControlMessageIPPacketInfo
 		}
 	case linux.SOL_IPV6:
 		switch name {
-		case linux.IPV6_TCLASS, linux.IPV6_RECVTCLASS, linux.IPV6_V6ONLY, linux.IPV6_RECVORIGDSTADDR:
+		case linux.IPV6_TCLASS, linux.IPV6_RECVTCLASS, linux.IPV6_RECVERR, linux.IPV6_V6ONLY, linux.IPV6_RECVORIGDSTADDR:
 			optlen = sizeofInt32
 		}
 	case linux.SOL_SOCKET:

pkg/sentry/socket/netstack/netstack.go

@@ -1405,6 +1405,13 @@ func getSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 
 		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetReceiveTClass()))
 		return &v, nil
+	case linux.IPV6_RECVERR:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetRecvError()))
+		return &v, nil
 
 	case linux.IPV6_RECVORIGDSTADDR:
 		if outLen < sizeOfInt32 {
@@ -1579,6 +1586,14 @@ func getSockOptIP(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name in
 		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetReceiveTOS()))
 		return &v, nil
 
+	case linux.IP_RECVERR:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetRecvError()))
+		return &v, nil
+
 	case linux.IP_PKTINFO:
 		if outLen < sizeOfInt32 {
 			return nil, syserr.ErrInvalidArgument
@@ -2129,6 +2144,16 @@ func setSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 
 		ep.SocketOptions().SetReceiveTClass(v != 0)
 		return nil
+	case linux.IPV6_RECVERR:
+		if len(optVal) == 0 {
+			return nil
+		}
+		v, err := parseIntOrChar(optVal)
+		if err != nil {
+			return err
+		}
+		ep.SocketOptions().SetRecvError(v != 0)
+		return nil
 
 	case linux.IP6T_SO_SET_REPLACE:
 		if len(optVal) < linux.SizeOfIP6TReplace {
@@ -2317,6 +2342,17 @@ func setSockOptIP(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name in
 		ep.SocketOptions().SetReceiveTOS(v != 0)
 		return nil
 
+	case linux.IP_RECVERR:
+		if len(optVal) == 0 {
+			return nil
+		}
+		v, err := parseIntOrChar(optVal)
+		if err != nil {
+			return err
+		}
+		ep.SocketOptions().SetRecvError(v != 0)
+		return nil
+
 	case linux.IP_PKTINFO:
 		if len(optVal) == 0 {
 			return nil
@@ -2386,7 +2422,6 @@ func setSockOptIP(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name in
 		linux.IP_NODEFRAG,
 		linux.IP_OPTIONS,
 		linux.IP_PASSSEC,
-		linux.IP_RECVERR,
 		linux.IP_RECVFRAGSIZE,
 		linux.IP_RECVOPTS,
 		linux.IP_RECVTTL,
@@ -2462,7 +2497,6 @@ func emitUnimplementedEventIPv6(t *kernel.Task, name int) {
 		linux.IPV6_MULTICAST_IF,
 		linux.IPV6_MULTICAST_LOOP,
 		linux.IPV6_RECVDSTOPTS,
-		linux.IPV6_RECVERR,
 		linux.IPV6_RECVFRAGSIZE,
 		linux.IPV6_RECVHOPLIMIT,
 		linux.IPV6_RECVHOPOPTS,
@@ -2496,7 +2530,6 @@ func emitUnimplementedEventIP(t *kernel.Task, name int) {
 		linux.IP_PKTINFO,
 		linux.IP_PKTOPTIONS,
 		linux.IP_MTU_DISCOVER,
-		linux.IP_RECVERR,
 		linux.IP_RECVTTL,
 		linux.IP_RECVTOS,
 		linux.IP_MTU,
@@ -2798,6 +2831,23 @@ func (s *socketOpsCommon) updateTimestamp() {
 	}
 }
 
+// dequeueErr is analogous to net/core/skbuff.c:sock_dequeue_err_skb().
+func (s *socketOpsCommon) dequeueErr() *tcpip.SockError {
+	so := s.Endpoint.SocketOptions()
+	err := so.DequeueErr()
+	if err == nil {
+		return nil
+	}
+
+	// Update socket error to reflect ICMP errors in queue.
+	if nextErr := so.PeekErr(); nextErr != nil && nextErr.ErrOrigin.IsICMPErr() {
+		so.SetLastError(nextErr.Err)
+	} else if err.ErrOrigin.IsICMPErr() {
+		so.SetLastError(nil)
+	}
+	return err
+}
+
 // addrFamilyFromNetProto returns the address family identifier for the given
 // network protocol.
 func addrFamilyFromNetProto(net tcpip.NetworkProtocolNumber) int {
@@ -2814,7 +2864,7 @@ func addrFamilyFromNetProto(net tcpip.NetworkProtocolNumber) int {
 // recvErr handles MSG_ERRQUEUE for recvmsg(2).
 // This is analogous to net/ipv4/ip_sockglue.c:ip_recv_error().
 func (s *socketOpsCommon) recvErr(t *kernel.Task, dst usermem.IOSequence) (int, int, linux.SockAddr, uint32, socket.ControlMessages, *syserr.Error) {
-	sockErr := s.Endpoint.SocketOptions().DequeueErr()
+	sockErr := s.dequeueErr()
 	if sockErr == nil {
 		return 0, 0, nil, 0, socket.ControlMessages{}, syserr.ErrTryAgain
 	}

pkg/tcpip/header/icmpv4.go

@@ -16,6 +16,7 @@ package header
 
 import (
 	"encoding/binary"
+	"fmt"
 
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -213,3 +214,16 @@ func ICMPv4Checksum(h ICMPv4, vv buffer.VectorisedView) uint16 {
 
 	return xsum
 }
+
+// ICMPOriginFromNetProto returns the appropriate SockErrOrigin to use when
+// a packet having a `net` header causing an ICMP error.
+func ICMPOriginFromNetProto(net tcpip.NetworkProtocolNumber) tcpip.SockErrOrigin {
+	switch net {
+	case IPv4ProtocolNumber:
+		return tcpip.SockExtErrorOriginICMP
+	case IPv6ProtocolNumber:
+		return tcpip.SockExtErrorOriginICMP6
+	default:
+		panic(fmt.Sprintf("unsupported net proto to extract ICMP error origin: %d", net))
+	}
+}

pkg/tcpip/socketops.go

@@ -42,6 +42,9 @@ type SocketOptionsHandler interface {
 
 	// LastError is invoked when SO_ERROR is read for an endpoint.
 	LastError() *Error
+
+	// UpdateLastError updates the endpoint specific last error field.
+	UpdateLastError(err *Error)
 }
 
 // DefaultSocketOptionsHandler is an embeddable type that implements no-op
@@ -70,6 +73,9 @@ func (*DefaultSocketOptionsHandler) LastError() *Error {
 	return nil
 }
 
+// UpdateLastError implements SocketOptionsHandler.UpdateLastError.
+func (*DefaultSocketOptionsHandler) UpdateLastError(*Error) {}
+
 // SocketOptions contains all the variables which store values for SOL_SOCKET,
 // SOL_IP, SOL_IPV6 and SOL_TCP level options.
 //
@@ -145,6 +151,10 @@ type SocketOptions struct {
 	// the incoming packet should be returned as an ancillary message.
 	receiveOriginalDstAddress uint32
 
+	// recvErrEnabled determines whether extended reliable error message passing
+	// is enabled.
+	recvErrEnabled uint32
+
 	// errQueue is the per-socket error queue. It is protected by errQueueMu.
 	errQueueMu sync.Mutex `state:"nosave"`
 	errQueue   sockErrorList
@@ -171,6 +181,11 @@ func storeAtomicBool(addr *uint32, v bool) {
 	atomic.StoreUint32(addr, val)
 }
 
+// SetLastError sets the last error for a socket.
+func (so *SocketOptions) SetLastError(err *Error) {
+	so.handler.UpdateLastError(err)
+}
+
 // GetBroadcast gets value for SO_BROADCAST option.
 func (so *SocketOptions) GetBroadcast() bool {
 	return atomic.LoadUint32(&so.broadcastEnabled) != 0
@@ -338,6 +353,19 @@ func (so *SocketOptions) SetReceiveOriginalDstAddress(v bool) {
 	storeAtomicBool(&so.receiveOriginalDstAddress, v)
 }
 
+// GetRecvError gets value for IP*_RECVERR option.
+func (so *SocketOptions) GetRecvError() bool {
+	return atomic.LoadUint32(&so.recvErrEnabled) != 0
+}
+
+// SetRecvError sets value for IP*_RECVERR option.
+func (so *SocketOptions) SetRecvError(v bool) {
+	storeAtomicBool(&so.recvErrEnabled, v)
+	if !v {
+		so.pruneErrQueue()
+	}
+}
+
 // GetLastError gets value for SO_ERROR option.
 func (so *SocketOptions) GetLastError() *Error {
 	return so.handler.LastError()
@@ -384,6 +412,11 @@ const (
 	SockExtErrorOriginICMP6
 )
 
+// IsICMPErr indicates if the error originated from an ICMP error.
+func (origin SockErrOrigin) IsICMPErr() bool {
+	return origin == SockExtErrorOriginICMP || origin == SockExtErrorOriginICMP6
+}
+
 // SockError represents a queue entry in the per-socket error queue.
 //
 // +stateify savable
@@ -411,6 +444,13 @@ type SockError struct {
 	NetProto NetworkProtocolNumber
 }
 
+// pruneErrQueue resets the queue.
+func (so *SocketOptions) pruneErrQueue() {
+	so.errQueueMu.Lock()
+	so.errQueue.Reset()
+	so.errQueueMu.Unlock()
+}
+
 // DequeueErr dequeues a socket extended error from the error queue and returns
 // it. Returns nil if queue is empty.
 func (so *SocketOptions) DequeueErr() *SockError {
@@ -423,3 +463,32 @@ func (so *SocketOptions) DequeueErr() *SockError {
 	}
 	return err
 }
+
+// PeekErr returns the error in the front of the error queue. Returns nil if
+// the error queue is empty.
+func (so *SocketOptions) PeekErr() *SockError {
+	so.errQueueMu.Lock()
+	defer so.errQueueMu.Unlock()
+	return so.errQueue.Front()
+}
+
+// QueueErr inserts the error at the back of the error queue.
+//
+// Preconditions: so.GetRecvError() == true.
+func (so *SocketOptions) QueueErr(err *SockError) {
+	so.errQueueMu.Lock()
+	defer so.errQueueMu.Unlock()
+	so.errQueue.PushBack(err)
+}
+
+// QueueLocalErr queues a local error onto the local queue.
+func (so *SocketOptions) QueueLocalErr(err *Error, net NetworkProtocolNumber, info uint32, dst FullAddress, payload []byte) {
+	so.QueueErr(&SockError{
+		Err:       err,
+		ErrOrigin: SockExtErrorOriginLocal,
+		ErrInfo:   info,
+		Payload:   payload,
+		Dst:       dst,
+		NetProto:  net,
+	})
+}

pkg/tcpip/transport/packet/endpoint.go

@@ -366,6 +366,13 @@ func (ep *endpoint) LastError() *tcpip.Error {
 	return err
 }
 
+// UpdateLastError implements tcpip.SocketOptionsHandler.UpdateLastError.
+func (ep *endpoint) UpdateLastError(err *tcpip.Error) {
+	ep.lastErrorMu.Lock()
+	ep.lastError = err
+	ep.lastErrorMu.Unlock()
+}
+
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (ep *endpoint) GetSockOpt(opt tcpip.GettableSocketOption) *tcpip.Error {
 	return tcpip.ErrNotSupported

pkg/tcpip/transport/tcp/endpoint.go

@@ -1303,6 +1303,15 @@ func (e *endpoint) LastError() *tcpip.Error {
 	return e.lastErrorLocked()
 }
 
+// UpdateLastError implements tcpip.SocketOptionsHandler.UpdateLastError.
+func (e *endpoint) UpdateLastError(err *tcpip.Error) {
+	e.LockUser()
+	e.lastErrorMu.Lock()
+	e.lastError = err
+	e.lastErrorMu.Unlock()
+	e.UnlockUser()
+}
+
 // Read reads data from the endpoint.
 func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
 	e.LockUser()
@@ -2708,6 +2717,41 @@ func (e *endpoint) enqueueSegment(s *segment) bool {
 	return true
 }
 
+func (e *endpoint) onICMPError(err *tcpip.Error, id stack.TransportEndpointID, errType byte, errCode byte, extra uint32, pkt *stack.PacketBuffer) {
+	// Update last error first.
+	e.lastErrorMu.Lock()
+	e.lastError = err
+	e.lastErrorMu.Unlock()
+
+	// Update the error queue if IP_RECVERR is enabled.
+	if e.SocketOptions().GetRecvError() {
+		e.SocketOptions().QueueErr(&tcpip.SockError{
+			Err:       err,
+			ErrOrigin: header.ICMPOriginFromNetProto(pkt.NetworkProtocolNumber),
+			ErrType:   errType,
+			ErrCode:   errCode,
+			ErrInfo:   extra,
+			// Linux passes the payload with the TCP header. We don't know if the TCP
+			// header even exists, it may not for fragmented packets.
+			Payload: pkt.Data.ToView(),
+			Dst: tcpip.FullAddress{
+				NIC:  pkt.NICID,
+				Addr: id.RemoteAddress,
+				Port: id.RemotePort,
+			},
+			Offender: tcpip.FullAddress{
+				NIC:  pkt.NICID,
+				Addr: id.LocalAddress,
+				Port: id.LocalPort,
+			},
+			NetProto: pkt.NetworkProtocolNumber,
+		})
+	}
+
+	// Notify of the error.
+	e.notifyProtocolGoroutine(notifyError)
+}
+
 // HandleControlPacket implements stack.TransportEndpoint.HandleControlPacket.
 func (e *endpoint) HandleControlPacket(id stack.TransportEndpointID, typ stack.ControlType, extra uint32, pkt *stack.PacketBuffer) {
 	switch typ {
@@ -2722,16 +2766,10 @@ func (e *endpoint) HandleControlPacket(id stack.TransportEndpointID, typ stack.C
 		e.notifyProtocolGoroutine(notifyMTUChanged)
 
 	case stack.ControlNoRoute:
-		e.lastErrorMu.Lock()
-		e.lastError = tcpip.ErrNoRoute
-		e.lastErrorMu.Unlock()
-		e.notifyProtocolGoroutine(notifyError)
+		e.onICMPError(tcpip.ErrNoRoute, id, byte(header.ICMPv4DstUnreachable), byte(header.ICMPv4HostUnreachable), extra, pkt)
 
 	case stack.ControlNetworkUnreachable:
-		e.lastErrorMu.Lock()
-		e.lastError = tcpip.ErrNetworkUnreachable
-		e.lastErrorMu.Unlock()
-		e.notifyProtocolGoroutine(notifyError)
+		e.onICMPError(tcpip.ErrNetworkUnreachable, id, byte(header.ICMPv6DstUnreachable), byte(header.ICMPv6NetworkUnreachable), extra, pkt)
 	}
 }
 

pkg/tcpip/transport/udp/endpoint.go

@@ -226,6 +226,13 @@ func (e *endpoint) LastError() *tcpip.Error {
 	return err
 }
 
+// UpdateLastError implements tcpip.SocketOptionsHandler.UpdateLastError.
+func (e *endpoint) UpdateLastError(err *tcpip.Error) {
+	e.lastErrorMu.Lock()
+	e.lastError = err
+	e.lastErrorMu.Unlock()
+}
+
 // Abort implements stack.TransportEndpoint.Abort.
 func (e *endpoint) Abort() {
 	e.Close()
@@ -511,6 +518,20 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c
 	}
 	if len(v) > header.UDPMaximumPacketSize {
 		// Payload can't possibly fit in a packet.
+		so := e.SocketOptions()
+		if so.GetRecvError() {
+			so.QueueLocalErr(
+				tcpip.ErrMessageTooLong,
+				route.NetProto,
+				header.UDPMaximumPacketSize,
+				tcpip.FullAddress{
+					NIC:  route.NICID(),
+					Addr: route.RemoteAddress,
+					Port: dstPort,
+				},
+				v,
+			)
+		}
 		return 0, nil, tcpip.ErrMessageTooLong
 	}
 
@@ -1338,15 +1359,63 @@ func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketB
 	}
 }
 
+func (e *endpoint) onICMPError(err *tcpip.Error, id stack.TransportEndpointID, errType byte, errCode byte, extra uint32, pkt *stack.PacketBuffer) {
+	// Update last error first.
+	e.lastErrorMu.Lock()
+	e.lastError = err
+	e.lastErrorMu.Unlock()
+
+	// Update the error queue if IP_RECVERR is enabled.
+	if e.SocketOptions().GetRecvError() {
+		// Linux passes the payload without the UDP header.
+		var payload []byte
+		udp := header.UDP(pkt.Data.ToView())
+		if len(udp) >= header.UDPMinimumSize {
+			payload = udp.Payload()
+		}
+
+		e.SocketOptions().QueueErr(&tcpip.SockError{
+			Err:       err,
+			ErrOrigin: header.ICMPOriginFromNetProto(pkt.NetworkProtocolNumber),
+			ErrType:   errType,
+			ErrCode:   errCode,
+			ErrInfo:   extra,
+			Payload:   payload,
+			Dst: tcpip.FullAddress{
+				NIC:  pkt.NICID,
+				Addr: id.RemoteAddress,
+				Port: id.RemotePort,
+			},
+			Offender: tcpip.FullAddress{
+				NIC:  pkt.NICID,
+				Addr: id.LocalAddress,
+				Port: id.LocalPort,
+			},
+			NetProto: pkt.NetworkProtocolNumber,
+		})
+	}
+
+	// Notify of the error.
+	e.waiterQueue.Notify(waiter.EventErr)
+}
+
 // HandleControlPacket implements stack.TransportEndpoint.HandleControlPacket.
 func (e *endpoint) HandleControlPacket(id stack.TransportEndpointID, typ stack.ControlType, extra uint32, pkt *stack.PacketBuffer) {
 	if typ == stack.ControlPortUnreachable {
 		if e.EndpointState() == StateConnected {
-			e.lastErrorMu.Lock()
-			e.lastError = tcpip.ErrConnectionRefused
-			e.lastErrorMu.Unlock()
-
-			e.waiterQueue.Notify(waiter.EventErr)
+			var errType byte
+			var errCode byte
+			switch pkt.NetworkProtocolNumber {
+			case header.IPv4ProtocolNumber:
+				errType = byte(header.ICMPv4DstUnreachable)
+				errCode = byte(header.ICMPv4PortUnreachable)
+			case header.IPv6ProtocolNumber:
+				errType = byte(header.ICMPv6DstUnreachable)
+				errCode = byte(header.ICMPv6PortUnreachable)
+			default:
+				panic(fmt.Sprintf("unsupported net proto for infering ICMP type and code: %d", pkt.NetworkProtocolNumber))
+			}
+			e.onICMPError(tcpip.ErrConnectionRefused, id, errType, errCode, extra, pkt)
 			return
 		}
 	}

runsc/boot/filter/config.go

@@ -351,6 +351,11 @@ func hostInetFilters() seccomp.SyscallRules {
 				seccomp.EqualTo(syscall.SOL_IP),
 				seccomp.EqualTo(syscall.IP_RECVORIGDSTADDR),
 			},
+			{
+				seccomp.MatchAny{},
+				seccomp.EqualTo(syscall.SOL_IP),
+				seccomp.EqualTo(syscall.IP_RECVERR),
+			},
 			{
 				seccomp.MatchAny{},
 				seccomp.EqualTo(syscall.SOL_IPV6),
@@ -361,6 +366,11 @@ func hostInetFilters() seccomp.SyscallRules {
 				seccomp.EqualTo(syscall.SOL_IPV6),
 				seccomp.EqualTo(syscall.IPV6_RECVTCLASS),
 			},
+			{
+				seccomp.MatchAny{},
+				seccomp.EqualTo(syscall.SOL_IPV6),
+				seccomp.EqualTo(syscall.IPV6_RECVERR),
+			},
 			{
 				seccomp.MatchAny{},
 				seccomp.EqualTo(syscall.SOL_IPV6),
@@ -444,13 +454,6 @@ func hostInetFilters() seccomp.SyscallRules {
 		syscall.SYS_SENDMSG:  {},
 		syscall.SYS_SENDTO:   {},
 		syscall.SYS_SETSOCKOPT: []seccomp.Rule{
-			{
-				seccomp.MatchAny{},
-				seccomp.EqualTo(syscall.SOL_IPV6),
-				seccomp.EqualTo(syscall.IPV6_V6ONLY),
-				seccomp.MatchAny{},
-				seccomp.EqualTo(4),
-			},
 			{
 				seccomp.MatchAny{},
 				seccomp.EqualTo(syscall.SOL_SOCKET),
@@ -521,6 +524,13 @@ func hostInetFilters() seccomp.SyscallRules {
 				seccomp.MatchAny{},
 				seccomp.EqualTo(4),
 			},
+			{
+				seccomp.MatchAny{},
+				seccomp.EqualTo(syscall.SOL_IP),
+				seccomp.EqualTo(syscall.IP_RECVERR),
+				seccomp.MatchAny{},
+				seccomp.EqualTo(4),
+			},
 			{
 				seccomp.MatchAny{},
 				seccomp.EqualTo(syscall.SOL_IPV6),
@@ -542,6 +552,20 @@ func hostInetFilters() seccomp.SyscallRules {
 				seccomp.MatchAny{},
 				seccomp.EqualTo(4),
 			},
+			{
+				seccomp.MatchAny{},
+				seccomp.EqualTo(syscall.SOL_IPV6),
+				seccomp.EqualTo(syscall.IPV6_RECVERR),
+				seccomp.MatchAny{},
+				seccomp.EqualTo(4),
+			},
+			{
+				seccomp.MatchAny{},
+				seccomp.EqualTo(syscall.SOL_IPV6),
+				seccomp.EqualTo(syscall.IPV6_V6ONLY),
+				seccomp.MatchAny{},
+				seccomp.EqualTo(4),
+			},
 		},
 		syscall.SYS_SHUTDOWN: []seccomp.Rule{
 			{

test/syscalls/linux/udp_socket.cc

@@ -14,6 +14,8 @@
 
 #include <arpa/inet.h>
 #include <fcntl.h>
+#include <netinet/icmp6.h>
+#include <netinet/ip_icmp.h>
 
 #include <ctime>
 
@@ -779,6 +781,94 @@ TEST_P(UdpSocketTest, ConnectAndSendNoReceiver) {
               SyscallFailsWithErrno(ECONNREFUSED));
 }
 
+#ifdef __linux__
+TEST_P(UdpSocketTest, RecvErrorConnRefused) {
+  // We will simulate an ICMP error and verify that we do receive that error via
+  // recvmsg(MSG_ERRQUEUE).
+  ASSERT_NO_ERRNO(BindLoopback());
+  // Close the socket to release the port so that we get an ICMP error.
+  ASSERT_THAT(close(bind_.release()), SyscallSucceeds());
+
+  // Set IP_RECVERR socket option to enable error queueing.
+  int v = kSockOptOn;
+  socklen_t optlen = sizeof(v);
+  int opt_level = SOL_IP;
+  int opt_type = IP_RECVERR;
+  if (GetParam() != AddressFamily::kIpv4) {
+    opt_level = SOL_IPV6;
+    opt_type = IPV6_RECVERR;
+  }
+  ASSERT_THAT(setsockopt(sock_.get(), opt_level, opt_type, &v, optlen),
+              SyscallSucceeds());
+
+  // Connect to loopback:bind_addr_ which should *hopefully* not be bound by an
+  // UDP socket. There is no easy way to ensure that the UDP port is not bound
+  // by another conncurrently running test. *This is potentially flaky*.
+  const int kBufLen = 300;
+  ASSERT_THAT(connect(sock_.get(), bind_addr_, addrlen_), SyscallSucceeds());
+  char buf[kBufLen];
+  RandomizeBuffer(buf, sizeof(buf));
+  // Send from sock_ to an unbound port. This should cause ECONNREFUSED.
+  EXPECT_THAT(send(sock_.get(), buf, sizeof(buf), 0),
+              SyscallSucceedsWithValue(sizeof(buf)));
+
+  // Dequeue error using recvmsg(MSG_ERRQUEUE).
+  char got[kBufLen];
+  struct iovec iov;
+  iov.iov_base = reinterpret_cast<void*>(got);
+  iov.iov_len = kBufLen;
+
+  size_t control_buf_len = CMSG_SPACE(sizeof(sock_extended_err) + addrlen_);
+  char* control_buf = static_cast<char*>(calloc(1, control_buf_len));
+  struct sockaddr_storage remote;
+  memset(&remote, 0, sizeof(remote));
+  struct msghdr msg = {};
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+  msg.msg_flags = 0;
+  msg.msg_control = control_buf;
+  msg.msg_controllen = control_buf_len;
+  msg.msg_name = reinterpret_cast<void*>(&remote);
+  msg.msg_namelen = addrlen_;
+  ASSERT_THAT(recvmsg(sock_.get(), &msg, MSG_ERRQUEUE),
+              SyscallSucceedsWithValue(kBufLen));
+
+  // Check the contents of msg.
+  EXPECT_EQ(memcmp(got, buf, sizeof(buf)), 0);  // iovec check
+  EXPECT_NE(msg.msg_flags & MSG_ERRQUEUE, 0);
+  EXPECT_EQ(memcmp(&remote, bind_addr_, addrlen_), 0);
+
+  // Check the contents of the control message.
+  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
+  ASSERT_NE(cmsg, nullptr);
+  EXPECT_EQ(CMSG_NXTHDR(&msg, cmsg), nullptr);
+  EXPECT_EQ(cmsg->cmsg_level, opt_level);
+  EXPECT_EQ(cmsg->cmsg_type, opt_type);
+
+  // Check the contents of socket error.
+  struct sock_extended_err* sock_err =
+      (struct sock_extended_err*)CMSG_DATA(cmsg);
+  EXPECT_EQ(sock_err->ee_errno, ECONNREFUSED);
+  if (GetParam() == AddressFamily::kIpv4) {
+    EXPECT_EQ(sock_err->ee_origin, SO_EE_ORIGIN_ICMP);
+    EXPECT_EQ(sock_err->ee_type, ICMP_DEST_UNREACH);
+    EXPECT_EQ(sock_err->ee_code, ICMP_PORT_UNREACH);
+  } else {
+    EXPECT_EQ(sock_err->ee_origin, SO_EE_ORIGIN_ICMP6);
+    EXPECT_EQ(sock_err->ee_type, ICMP6_DST_UNREACH);
+    EXPECT_EQ(sock_err->ee_code, ICMP6_DST_UNREACH_NOPORT);
+  }
+
+  // Now verify that the socket error was cleared by recvmsg(MSG_ERRQUEUE).
+  int err;
+  optlen = sizeof(err);
+  ASSERT_THAT(getsockopt(sock_.get(), SOL_SOCKET, SO_ERROR, &err, &optlen),
+              SyscallSucceeds());
+  ASSERT_EQ(err, 0);
+  ASSERT_EQ(optlen, sizeof(err));
+}
+#endif  // __linux__
+
 TEST_P(UdpSocketTest, ZerolengthWriteAllowed) {
   // TODO(gvisor.dev/issue/1202): Hostinet does not support zero length writes.
   SKIP_IF(IsRunningWithHostinet());