From 71bf90c55bd888f9b9c493533ca5e4b2b4b3d21d Mon Sep 17 00:00:00 2001
From: Bhasker Hariharan <bhaskerh@google.com>
Date: Wed, 22 Jul 2020 15:12:56 -0700
Subject: Support for receiving outbound packets in AF_PACKET.

Updates #173

PiperOrigin-RevId: 322665518
---
 pkg/sentry/socket/netstack/netstack.go | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'pkg/sentry/socket/netstack')

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 49a04e613..964ec8414 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -26,6 +26,7 @@ package netstack
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"math"
 	"reflect"
@@ -2468,6 +2469,23 @@ func (s *socketOpsCommon) fillCmsgInq(cmsg *socket.ControlMessages) {
 	cmsg.IP.Inq = int32(len(s.readView) + rcvBufUsed)
 }
 
+func toLinuxPacketType(pktType tcpip.PacketType) uint8 {
+	switch pktType {
+	case tcpip.PacketHost:
+		return linux.PACKET_HOST
+	case tcpip.PacketOtherHost:
+		return linux.PACKET_OTHERHOST
+	case tcpip.PacketOutgoing:
+		return linux.PACKET_OUTGOING
+	case tcpip.PacketBroadcast:
+		return linux.PACKET_BROADCAST
+	case tcpip.PacketMulticast:
+		return linux.PACKET_MULTICAST
+	default:
+		panic(fmt.Sprintf("unknown packet type: %d", pktType))
+	}
+}
+
 // nonBlockingRead issues a non-blocking read.
 //
 // TODO(b/78348848): Support timestamps for stream sockets.
@@ -2526,6 +2544,7 @@ func (s *socketOpsCommon) nonBlockingRead(ctx context.Context, dst usermem.IOSeq
 		switch v := addr.(type) {
 		case *linux.SockAddrLink:
 			v.Protocol = htons(uint16(s.linkPacketInfo.Protocol))
+			v.PacketType = toLinuxPacketType(s.linkPacketInfo.PktType)
 		}
 	}
 
-- 
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