From d7fd00bad1416fb44b3303331ee223c28c69fe9b Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Tue, 6 Apr 2021 10:14:10 -0700
Subject: Do not perform MLD for certain multicast scopes
...as per RFC 2710 section 5 page 10.
Test: ipv6_test.TestMLDSkipProtocol
PiperOrigin-RevId: 367031126
---
pkg/tcpip/header/ipv6.go | 49 ++++++++++++++++++++++----
pkg/tcpip/header/ipv6_test.go | 80 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 123 insertions(+), 6 deletions(-)
(limited to 'pkg/tcpip/header')
diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go
index f2403978c..7711abec1 100644
--- a/pkg/tcpip/header/ipv6.go
+++ b/pkg/tcpip/header/ipv6.go
@@ -142,11 +142,6 @@ const (
// ipv6MulticastAddressScopeMask is the mask for the scope (scop) field,
// within the byte holding the field, as per RFC 4291 section 2.7.
ipv6MulticastAddressScopeMask = 0xF
-
- // ipv6LinkLocalMulticastScope is the value of the scope (scop) field within
- // a multicast IPv6 address that indicates the address has link-local scope,
- // as per RFC 4291 section 2.7.
- ipv6LinkLocalMulticastScope = 2
)
// IPv6EmptySubnet is the empty IPv6 subnet. It may also be known as the
@@ -399,7 +394,7 @@ func IsV6LoopbackAddress(addr tcpip.Address) bool {
// IsV6LinkLocalMulticastAddress determines if the provided address is an IPv6
// link-local multicast address.
func IsV6LinkLocalMulticastAddress(addr tcpip.Address) bool {
- return IsV6MulticastAddress(addr) && addr[ipv6MulticastAddressScopeByteIdx]&ipv6MulticastAddressScopeMask == ipv6LinkLocalMulticastScope
+ return IsV6MulticastAddress(addr) && V6MulticastScope(addr) == IPv6LinkLocalMulticastScope
}
// AppendOpaqueInterfaceIdentifier appends a 64 bit opaque interface identifier
@@ -520,3 +515,45 @@ func GenerateTempIPv6SLAACAddr(tempIIDHistory []byte, stableAddr tcpip.Address)
PrefixLen: IIDOffsetInIPv6Address * 8,
}
}
+
+// IPv6MulticastScope is the scope of a multicast IPv6 address.
+type IPv6MulticastScope uint8
+
+// The various values for IPv6 multicast scopes, as per RFC 7346 section 2:
+//
+// +------+--------------------------+-------------------------+
+// | scop | NAME | REFERENCE |
+// +------+--------------------------+-------------------------+
+// | 0 | Reserved | [RFC4291], RFC 7346 |
+// | 1 | Interface-Local scope | [RFC4291], RFC 7346 |
+// | 2 | Link-Local scope | [RFC4291], RFC 7346 |
+// | 3 | Realm-Local scope | [RFC4291], RFC 7346 |
+// | 4 | Admin-Local scope | [RFC4291], RFC 7346 |
+// | 5 | Site-Local scope | [RFC4291], RFC 7346 |
+// | 6 | Unassigned | |
+// | 7 | Unassigned | |
+// | 8 | Organization-Local scope | [RFC4291], RFC 7346 |
+// | 9 | Unassigned | |
+// | A | Unassigned | |
+// | B | Unassigned | |
+// | C | Unassigned | |
+// | D | Unassigned | |
+// | E | Global scope | [RFC4291], RFC 7346 |
+// | F | Reserved | [RFC4291], RFC 7346 |
+// +------+--------------------------+-------------------------+
+const (
+ IPv6Reserved0MulticastScope = IPv6MulticastScope(0x0)
+ IPv6InterfaceLocalMulticastScope = IPv6MulticastScope(0x1)
+ IPv6LinkLocalMulticastScope = IPv6MulticastScope(0x2)
+ IPv6RealmLocalMulticastScope = IPv6MulticastScope(0x3)
+ IPv6AdminLocalMulticastScope = IPv6MulticastScope(0x4)
+ IPv6SiteLocalMulticastScope = IPv6MulticastScope(0x5)
+ IPv6OrganizationLocalMulticastScope = IPv6MulticastScope(0x8)
+ IPv6GlobalMulticastScope = IPv6MulticastScope(0xE)
+ IPv6ReservedFMulticastScope = IPv6MulticastScope(0xF)
+)
+
+// V6MulticastScope returns the scope of a multicast address.
+func V6MulticastScope(addr tcpip.Address) IPv6MulticastScope {
+ return IPv6MulticastScope(addr[ipv6MulticastAddressScopeByteIdx] & ipv6MulticastAddressScopeMask)
+}
diff --git a/pkg/tcpip/header/ipv6_test.go b/pkg/tcpip/header/ipv6_test.go
index f10f446a6..38b6dbc18 100644
--- a/pkg/tcpip/header/ipv6_test.go
+++ b/pkg/tcpip/header/ipv6_test.go
@@ -373,3 +373,83 @@ func TestSolicitedNodeAddr(t *testing.T) {
})
}
}
+
+func TestV6MulticastScope(t *testing.T) {
+ tests := []struct {
+ addr tcpip.Address
+ want header.IPv6MulticastScope
+ }{
+ {
+ addr: "\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6Reserved0MulticastScope,
+ },
+ {
+ addr: "\xff\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6InterfaceLocalMulticastScope,
+ },
+ {
+ addr: "\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6LinkLocalMulticastScope,
+ },
+ {
+ addr: "\xff\x03\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6RealmLocalMulticastScope,
+ },
+ {
+ addr: "\xff\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6AdminLocalMulticastScope,
+ },
+ {
+ addr: "\xff\x05\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6SiteLocalMulticastScope,
+ },
+ {
+ addr: "\xff\x06\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(6),
+ },
+ {
+ addr: "\xff\x07\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(7),
+ },
+ {
+ addr: "\xff\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6OrganizationLocalMulticastScope,
+ },
+ {
+ addr: "\xff\x09\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(9),
+ },
+ {
+ addr: "\xff\x0a\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(10),
+ },
+ {
+ addr: "\xff\x0b\x03\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(11),
+ },
+ {
+ addr: "\xff\x0c\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(12),
+ },
+ {
+ addr: "\xff\x0d\x05\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6MulticastScope(13),
+ },
+ {
+ addr: "\xff\x0e\x06\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6GlobalMulticastScope,
+ },
+ {
+ addr: "\xff\x0f\x06\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ want: header.IPv6ReservedFMulticastScope,
+ },
+ }
+
+ for _, test := range tests {
+ t.Run(fmt.Sprintf("%s", test.addr), func(t *testing.T) {
+ if got := header.V6MulticastScope(test.addr); got != test.want {
+ t.Fatalf("got header.V6MulticastScope(%s) = %d, want = %d", test.addr, got, test.want)
+ }
+ })
+ }
+}
--
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