Support IPV6_RECVPKTINFO on UDP sockets

PiperOrigin-RevId: 397631833

3 files changed, 63 insertions, 2 deletions

diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go
index 00a5e729a..f9a5b0df1 100644
--- a/pkg/sentry/socket/control/control.go
+++ b/pkg/sentry/socket/control/control.go
@@ -355,6 +355,17 @@ func PackIPPacketInfo(t *kernel.Task, packetInfo *linux.ControlMessageIPPacketIn
 	)
 }
 
+// PackIPv6PacketInfo packs an IPV6_PKTINFO socket control message.
+func PackIPv6PacketInfo(t *kernel.Task, packetInfo *linux.ControlMessageIPv6PacketInfo, buf []byte) []byte {
+	return putCmsgStruct(
+		buf,
+		linux.SOL_IPV6,
+		linux.IPV6_PKTINFO,
+		t.Arch().Width(),
+		packetInfo,
+	)
+}
+
 // PackOriginalDstAddress packs an IP_RECVORIGINALDSTADDR socket control message.
 func PackOriginalDstAddress(t *kernel.Task, originalDstAddress linux.SockAddr, buf []byte) []byte {
 	var level uint32
@@ -412,6 +423,10 @@ func PackControlMessages(t *kernel.Task, cmsgs socket.ControlMessages, buf []byt
 		buf = PackIPPacketInfo(t, &cmsgs.IP.PacketInfo, buf)
 	}
 
+	if cmsgs.IP.HasIPv6PacketInfo {
+		buf = PackIPv6PacketInfo(t, &cmsgs.IP.IPv6PacketInfo, buf)
+	}
+
 	if cmsgs.IP.OriginalDstAddress != nil {
 		buf = PackOriginalDstAddress(t, cmsgs.IP.OriginalDstAddress, buf)
 	}
@@ -453,6 +468,10 @@ func CmsgsSpace(t *kernel.Task, cmsgs socket.ControlMessages) int {
 		space += cmsgSpace(t, linux.SizeOfControlMessageIPPacketInfo)
 	}
 
+	if cmsgs.IP.HasIPv6PacketInfo {
+		space += cmsgSpace(t, linux.SizeOfControlMessageIPv6PacketInfo)
+	}
+
 	if cmsgs.IP.OriginalDstAddress != nil {
 		space += cmsgSpace(t, cmsgs.IP.OriginalDstAddress.SizeBytes())
 	}
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index aa081e90d..dedc32dda 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -1371,6 +1371,14 @@ func getSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetReceiveOriginalDstAddress()))
 		return &v, nil
 
+	case linux.IPV6_RECVPKTINFO:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetIPv6ReceivePacketInfo()))
+		return &v, nil
+
 	case linux.IP6T_ORIGINAL_DST:
 		if outLen < sockAddrInet6Size {
 			return nil, syserr.ErrInvalidArgument
@@ -2127,6 +2135,15 @@ func setSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 		ep.SocketOptions().SetReceiveOriginalDstAddress(v != 0)
 		return nil
 
+	case linux.IPV6_RECVPKTINFO:
+		if len(optVal) < sizeOfInt32 {
+			return syserr.ErrInvalidArgument
+		}
+		v := int32(hostarch.ByteOrder.Uint32(optVal))
+
+		ep.SocketOptions().SetIPv6ReceivePacketInfo(v != 0)
+		return nil
+
 	case linux.IPV6_TCLASS:
 		if len(optVal) < sizeOfInt32 {
 			return syserr.ErrInvalidArgument
@@ -2516,7 +2533,6 @@ func emitUnimplementedEventIPv6(t *kernel.Task, name int) {
 		linux.IPV6_RECVHOPLIMIT,
 		linux.IPV6_RECVHOPOPTS,
 		linux.IPV6_RECVPATHMTU,
-		linux.IPV6_RECVPKTINFO,
 		linux.IPV6_RECVRTHDR,
 		linux.IPV6_RTHDR,
 		linux.IPV6_RTHDRDSTOPTS,
@@ -2742,6 +2758,8 @@ func (s *socketOpsCommon) controlMessages(cm tcpip.ControlMessages) socket.Contr
 			TClass:             readCM.TClass,
 			HasIPPacketInfo:    readCM.HasIPPacketInfo,
 			PacketInfo:         readCM.PacketInfo,
+			HasIPv6PacketInfo:  readCM.HasIPv6PacketInfo,
+			IPv6PacketInfo:     readCM.IPv6PacketInfo,
 			OriginalDstAddress: readCM.OriginalDstAddress,
 			SockErr:            readCM.SockErr,
 		},
diff --git a/pkg/sentry/socket/socket.go b/pkg/sentry/socket/socket.go
index 841d5bd55..2f0eb4a6c 100644
--- a/pkg/sentry/socket/socket.go
+++ b/pkg/sentry/socket/socket.go
@@ -56,6 +56,17 @@ func packetInfoToLinux(packetInfo tcpip.IPPacketInfo) linux.ControlMessageIPPack
 	return p
 }
 
+// ipv6PacketInfoToLinux converts IPv6PacketInfo from tcpip format to Linux
+// format.
+func ipv6PacketInfoToLinux(packetInfo tcpip.IPv6PacketInfo) linux.ControlMessageIPv6PacketInfo {
+	var p linux.ControlMessageIPv6PacketInfo
+	if n := copy(p.Addr[:], []byte(packetInfo.Addr)); n != len(p.Addr) {
+		panic(fmt.Sprintf("got copy(%x, %x) = %d, want = %d", p.Addr, packetInfo.Addr, n, len(p.Addr)))
+	}
+	p.NIC = uint32(packetInfo.NIC)
+	return p
+}
+
 // errOriginToLinux maps tcpip socket origin to Linux socket origin constants.
 func errOriginToLinux(origin tcpip.SockErrOrigin) uint8 {
 	switch origin {
@@ -114,7 +125,7 @@ func NewIPControlMessages(family int, cmgs tcpip.ControlMessages) IPControlMessa
 	if cmgs.HasOriginalDstAddress {
 		orgDstAddr, _ = ConvertAddress(family, cmgs.OriginalDstAddress)
 	}
-	return IPControlMessages{
+	cm := IPControlMessages{
 		HasTimestamp:       cmgs.HasTimestamp,
 		Timestamp:          cmgs.Timestamp,
 		HasInq:             cmgs.HasInq,
@@ -125,9 +136,16 @@ func NewIPControlMessages(family int, cmgs tcpip.ControlMessages) IPControlMessa
 		TClass:             cmgs.TClass,
 		HasIPPacketInfo:    cmgs.HasIPPacketInfo,
 		PacketInfo:         packetInfoToLinux(cmgs.PacketInfo),
+		HasIPv6PacketInfo:  cmgs.HasIPv6PacketInfo,
 		OriginalDstAddress: orgDstAddr,
 		SockErr:            sockErrCmsgToLinux(cmgs.SockErr),
 	}
+
+	if cm.HasIPv6PacketInfo {
+		cm.IPv6PacketInfo = ipv6PacketInfoToLinux(cmgs.IPv6PacketInfo)
+	}
+
+	return cm
 }
 
 // IPControlMessages contains socket control messages for IP sockets.
@@ -166,6 +184,12 @@ type IPControlMessages struct {
 	// PacketInfo holds interface and address data on an incoming packet.
 	PacketInfo linux.ControlMessageIPPacketInfo
 
+	// HasIPv6PacketInfo indicates whether IPv6PacketInfo is set.
+	HasIPv6PacketInfo bool
+
+	// PacketInfo holds interface and address data on an incoming packet.
+	IPv6PacketInfo linux.ControlMessageIPv6PacketInfo
+
 	// OriginalDestinationAddress holds the original destination address
 	// and port of the incoming packet.
 	OriginalDstAddress linux.SockAddr