From 6f8d64f4229be58814319003a397b971ca9b4e1b Mon Sep 17 00:00:00 2001
From: Kevin Krakauer <krakauer@google.com>
Date: Wed, 30 Sep 2020 16:02:46 -0700
Subject: ip6tables: redirect support

Adds support for the IPv6-compatible redirect target. Redirection is a limited
form of DNAT, where the destination is always the localhost.

Updates #3549.

PiperOrigin-RevId: 334698344
---
 pkg/sentry/socket/netstack/netstack.go | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

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

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 335822c0e..87e30d742 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -1512,8 +1512,17 @@ func getSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 		return &vP, nil
 
 	case linux.IP6T_ORIGINAL_DST:
-		// TODO(gvisor.dev/issue/170): ip6tables.
-		return nil, syserr.ErrInvalidArgument
+		if outLen < int(binary.Size(linux.SockAddrInet6{})) {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		var v tcpip.OriginalDestinationOption
+		if err := ep.GetSockOpt(&v); err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+
+		a, _ := ConvertAddress(linux.AF_INET6, tcpip.FullAddress(v))
+		return a.(*linux.SockAddrInet6), nil
 
 	case linux.IP6T_SO_GET_INFO:
 		if outLen < linux.SizeOfIPTGetinfo {
@@ -1555,6 +1564,26 @@ func getSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 		}
 		return &entries, nil
 
+	case linux.IP6T_SO_GET_REVISION_TARGET:
+		if outLen < linux.SizeOfXTGetRevision {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		// Only valid for raw IPv6 sockets.
+		if family, skType, _ := s.Type(); family != linux.AF_INET6 || skType != linux.SOCK_RAW {
+			return nil, syserr.ErrProtocolNotAvailable
+		}
+
+		stack := inet.StackFromContext(t)
+		if stack == nil {
+			return nil, syserr.ErrNoDevice
+		}
+		ret, err := netfilter.TargetRevision(t, outPtr, header.IPv6ProtocolNumber)
+		if err != nil {
+			return nil, err
+		}
+		return &ret, nil
+
 	default:
 		emitUnimplementedEventIPv6(t, name)
 	}
-- 
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