From ad80dcf47077a1938631fe36f6b406256f3f3f4f Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Fri, 13 Dec 2019 16:26:06 -0800
Subject: Properly generate the EUI64 interface identifier from an Ethernet
address
Fixed a bug where the interface identifier was not properly generated from an
Ethernet address.
Tests: Unittests to make sure the functions generating the EUI64 interface
identifier are correct.
PiperOrigin-RevId: 285494562
---
pkg/tcpip/header/BUILD | 3 +++
pkg/tcpip/header/ipv6.go | 21 ++++++++++----------
pkg/tcpip/header/ipv6_test.go | 45 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 59 insertions(+), 10 deletions(-)
create mode 100644 pkg/tcpip/header/ipv6_test.go
(limited to 'pkg/tcpip/header')
diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD
index 8392cb9e5..f1d837196 100644
--- a/pkg/tcpip/header/BUILD
+++ b/pkg/tcpip/header/BUILD
@@ -38,12 +38,15 @@ go_test(
size = "small",
srcs = [
"checksum_test.go",
+ "ipv6_test.go",
"ipversion_test.go",
"tcp_test.go",
],
deps = [
":header",
+ "//pkg/tcpip",
"//pkg/tcpip/buffer",
+ "@com_github_google_go-cmp//cmp:go_default_library",
],
)
diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go
index 5275b34d4..fc671e439 100644
--- a/pkg/tcpip/header/ipv6.go
+++ b/pkg/tcpip/header/ipv6.go
@@ -278,33 +278,34 @@ func SolicitedNodeAddr(addr tcpip.Address) tcpip.Address {
return solicitedNodeMulticastPrefix + addr[len(addr)-3:]
}
-// EthernetAdddressToEUI64IntoBuf populates buf with a EUI-64 from a 48-bit
-// Ethernet/MAC address.
+// EthernetAdddressToModifiedEUI64IntoBuf populates buf with a modified EUI-64
+// from a 48-bit Ethernet/MAC address, as per RFC 4291 section 2.5.1.
//
// buf MUST be at least 8 bytes.
-func EthernetAdddressToEUI64IntoBuf(linkAddr tcpip.LinkAddress, buf []byte) {
+func EthernetAdddressToModifiedEUI64IntoBuf(linkAddr tcpip.LinkAddress, buf []byte) {
buf[0] = linkAddr[0] ^ 2
buf[1] = linkAddr[1]
buf[2] = linkAddr[2]
- buf[3] = 0xFE
+ buf[3] = 0xFF
buf[4] = 0xFE
buf[5] = linkAddr[3]
buf[6] = linkAddr[4]
buf[7] = linkAddr[5]
}
-// EthernetAddressToEUI64 computes an EUI-64 from a 48-bit Ethernet/MAC address.
-func EthernetAddressToEUI64(linkAddr tcpip.LinkAddress) [IIDSize]byte {
+// EthernetAddressToModifiedEUI64 computes a modified EUI-64 from a 48-bit
+// Ethernet/MAC address, as per RFC 4291 section 2.5.1.
+func EthernetAddressToModifiedEUI64(linkAddr tcpip.LinkAddress) [IIDSize]byte {
var buf [IIDSize]byte
- EthernetAdddressToEUI64IntoBuf(linkAddr, buf[:])
+ EthernetAdddressToModifiedEUI64IntoBuf(linkAddr, buf[:])
return buf
}
// LinkLocalAddr computes the default IPv6 link-local address from a link-layer
// (MAC) address.
func LinkLocalAddr(linkAddr tcpip.LinkAddress) tcpip.Address {
- // Convert a 48-bit MAC to an EUI-64 and then prepend the link-local
- // header, FE80::.
+ // Convert a 48-bit MAC to a modified EUI-64 and then prepend the
+ // link-local header, FE80::.
//
// The conversion is very nearly:
// aa:bb:cc:dd:ee:ff => FE80::Aabb:ccFF:FEdd:eeff
@@ -313,7 +314,7 @@ func LinkLocalAddr(linkAddr tcpip.LinkAddress) tcpip.Address {
0: 0xFE,
1: 0x80,
}
- EthernetAdddressToEUI64IntoBuf(linkAddr, lladdrb[IIDOffsetInIPv6Address:])
+ EthernetAdddressToModifiedEUI64IntoBuf(linkAddr, lladdrb[IIDOffsetInIPv6Address:])
return tcpip.Address(lladdrb[:])
}
diff --git a/pkg/tcpip/header/ipv6_test.go b/pkg/tcpip/header/ipv6_test.go
new file mode 100644
index 000000000..42c5c6fc1
--- /dev/null
+++ b/pkg/tcpip/header/ipv6_test.go
@@ -0,0 +1,45 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package header_test
+
+import (
+ "testing"
+
+ "github.com/google/go-cmp/cmp"
+ "gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/header"
+)
+
+const linkAddr = tcpip.LinkAddress("\x02\x02\x03\x04\x05\x06")
+
+func TestEthernetAdddressToModifiedEUI64(t *testing.T) {
+ expectedIID := [header.IIDSize]byte{0, 2, 3, 255, 254, 4, 5, 6}
+
+ if diff := cmp.Diff(expectedIID, header.EthernetAddressToModifiedEUI64(linkAddr)); diff != "" {
+ t.Errorf("EthernetAddressToModifiedEUI64(%s) mismatch (-want +got):\n%s", linkAddr, diff)
+ }
+
+ var buf [header.IIDSize]byte
+ header.EthernetAdddressToModifiedEUI64IntoBuf(linkAddr, buf[:])
+ if diff := cmp.Diff(expectedIID, buf); diff != "" {
+ t.Errorf("EthernetAddressToModifiedEUI64IntoBuf(%s, _) mismatch (-want +got):\n%s", linkAddr, diff)
+ }
+}
+
+func TestLinkLocalAddr(t *testing.T) {
+ if got, want := header.LinkLocalAddr(linkAddr), tcpip.Address("\xfe\x80\x00\x00\x00\x00\x00\x00\x00\x02\x03\xff\xfe\x04\x05\x06"); got != want {
+ t.Errorf("got LinkLocalAddr(%s) = %s, want = %s", linkAddr, got, want)
+ }
+}
--
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