From 56fd9504aab44a738d3df164cbee8e572b309f28 Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Tue, 18 Feb 2020 15:44:22 -0800
Subject: Enable IPV6_RECVTCLASS socket option for datagram sockets

Added the ability to get/set the IP_RECVTCLASS socket option on UDP endpoints.
If enabled, traffic class from the incoming Network Header passed as ancillary
data in the ControlMessages.

Adding Get/SetSockOptBool to decrease the overhead of getting/setting simple
options. (This was absorbed in a CL that will be landing before this one).

Test:
* Added unit test to udp_test.go that tests getting/setting as well as
verifying that we receive expected TOS from incoming packet.
* Added a syscall test for verifying getting/setting
* Removed test skip for existing syscall test to enable end to end test.
PiperOrigin-RevId: 295840218
---
 pkg/sentry/socket/control/control.go   |  2 +-
 pkg/sentry/socket/netstack/netstack.go | 27 ++++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

(limited to 'pkg/sentry')

diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go
index 4667373d2..8834a1e1a 100644
--- a/pkg/sentry/socket/control/control.go
+++ b/pkg/sentry/socket/control/control.go
@@ -329,7 +329,7 @@ func PackTOS(t *kernel.Task, tos uint8, buf []byte) []byte {
 }
 
 // PackTClass packs an IPV6_TCLASS socket control message.
-func PackTClass(t *kernel.Task, tClass int32, buf []byte) []byte {
+func PackTClass(t *kernel.Task, tClass uint32, buf []byte) []byte {
 	return putCmsgStruct(
 		buf,
 		linux.SOL_IPV6,
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 9757fbfba..e187276c5 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -1318,6 +1318,22 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf
 		}
 		return ib, nil
 
+	case linux.IPV6_RECVTCLASS:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		v, err := ep.GetSockOptBool(tcpip.ReceiveTClassOption)
+		if err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+
+		var o int32
+		if v {
+			o = 1
+		}
+		return o, nil
+
 	default:
 		emitUnimplementedEventIPv6(t, name)
 	}
@@ -1803,6 +1819,14 @@ func setSockOptIPv6(t *kernel.Task, ep commonEndpoint, name int, optVal []byte)
 		}
 		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.IPv6TrafficClassOption(v)))
 
+	case linux.IPV6_RECVTCLASS:
+		v, err := parseIntOrChar(optVal)
+		if err != nil {
+			return err
+		}
+
+		return syserr.TranslateNetstackError(ep.SetSockOptBool(tcpip.ReceiveTClassOption, v != 0))
+
 	default:
 		emitUnimplementedEventIPv6(t, name)
 	}
@@ -2086,7 +2110,6 @@ func emitUnimplementedEventIPv6(t *kernel.Task, name int) {
 		linux.IPV6_RECVPATHMTU,
 		linux.IPV6_RECVPKTINFO,
 		linux.IPV6_RECVRTHDR,
-		linux.IPV6_RECVTCLASS,
 		linux.IPV6_RTHDR,
 		linux.IPV6_RTHDRDSTOPTS,
 		linux.IPV6_TCLASS,
@@ -2424,6 +2447,8 @@ func (s *SocketOperations) controlMessages() socket.ControlMessages {
 			Timestamp:       s.readCM.Timestamp,
 			HasTOS:          s.readCM.HasTOS,
 			TOS:             s.readCM.TOS,
+			HasTClass:       s.readCM.HasTClass,
+			TClass:          s.readCM.TClass,
 			HasIPPacketInfo: s.readCM.HasIPPacketInfo,
 			PacketInfo:      s.readCM.PacketInfo,
 		},
-- 
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