all: sync with master, upd chlog
This commit is contained in:
Eugene Burkov
@@ -4,6 +4,7 @@ import (
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"encoding/binary"
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"fmt"
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"net"
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"slices"
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"sync/atomic"
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"time"
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@@ -14,18 +15,48 @@ import (
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"golang.org/x/net/ipv6"
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)
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// raCtx is a context for the Router Advertisement logic.
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type raCtx struct {
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raAllowSLAAC bool // send RA packets without MO flags
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raSLAACOnly bool // send RA packets with MO flags
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ipAddr net.IP // source IP address (link-local-unicast)
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dnsIPAddr net.IP // IP address for DNS Server option
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prefixIPAddr net.IP // IP address for Prefix option
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ifaceName string
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iface *net.Interface
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packetSendPeriod time.Duration // how often RA packets are sent
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// raAllowSLAAC is used to determine if the ICMP Router Advertisement
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// messages should be sent.
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//
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// If both raAllowSLAAC and raSLAACOnly are false, the Router Advertisement
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// messages aren't sent.
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raAllowSLAAC bool
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conn *icmp.PacketConn // ICMPv6 socket
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stop atomic.Value // stop the packet sending loop
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// raSLAACOnly is used to determine if the ICMP Router Advertisement
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// messages should set M and O flags, see RFC 4861, section 4.2.
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//
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// If both raAllowSLAAC and raSLAACOnly are false, the Router Advertisement
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// messages aren't sent.
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raSLAACOnly bool
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// ipAddr is an IP address used within the Source Link-Layer Address option.
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// See RFC 4861, section 4.6.1.
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ipAddr net.IP
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// dnsIPAddr is an IP address used within the DNS Server option.
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dnsIPAddr net.IP
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// prefixIPAddr is an IP address used within the Prefix Information option.
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// See RFC 4861, section 4.6.2.
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prefixIPAddr net.IP
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// ifaceName is the name of the interface used as a scope of the IP
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// addresses.
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ifaceName string
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// iface is the network interface used to send the ICMPv6 packets.
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iface *net.Interface
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// packetSendPeriod is the interval between sending the ICMPv6 packets.
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packetSendPeriod time.Duration
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// conn is the ICMPv6 socket.
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conn *icmp.PacketConn
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// stop is used to stop the packet sending loop.
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stop atomic.Value
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}
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type icmpv6RA struct {
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@@ -38,10 +69,11 @@ type icmpv6RA struct {
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mtu uint32
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}
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// hwAddrToLinkLayerAddr converts a hardware address into a form required by
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// RFC4861. That is, a byte slice of length divisible by 8.
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// hwAddrToLinkLayerAddr clones the hardware address and returns it as a byte
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// slice suitable for the Source Link-Layer Address option in the ICMPv6
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// Router Advertisement packet.
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//
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// See https://tools.ietf.org/html/rfc4861#section-4.6.1.
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// TODO(e.burkov): Check if it's safe to use the original slice.
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func hwAddrToLinkLayerAddr(hwa net.HardwareAddr) (lla []byte, err error) {
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err = netutil.ValidateMAC(hwa)
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if err != nil {
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@@ -50,19 +82,7 @@ func hwAddrToLinkLayerAddr(hwa net.HardwareAddr) (lla []byte, err error) {
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return nil, err
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}
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if len(hwa) == 6 || len(hwa) == 8 {
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lla = make([]byte, 8)
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copy(lla, hwa)
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return lla, nil
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}
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// Assume that netutil.ValidateMAC prevents lengths other than 20 by
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// now.
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lla = make([]byte, 24)
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copy(lla, hwa)
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return lla, nil
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return slices.Clone(hwa), nil
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}
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// Create an ICMPv6.RouterAdvertisement packet with all necessary options.
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@@ -103,15 +123,24 @@ func hwAddrToLinkLayerAddr(hwa net.HardwareAddr) (lla []byte, err error) {
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//
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// TODO(a.garipov): Replace with an existing implementation from a dependency.
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func createICMPv6RAPacket(params icmpv6RA) (data []byte, err error) {
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var lla []byte
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lla, err = hwAddrToLinkLayerAddr(params.sourceLinkLayerAddress)
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lla, err := hwAddrToLinkLayerAddr(params.sourceLinkLayerAddress)
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if err != nil {
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return nil, fmt.Errorf("converting source link layer address: %w", err)
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return nil, fmt.Errorf("converting source link-layer address: %w", err)
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}
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// Calculate length of the source link-layer address option. As per RFC
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// 4861, section 4.6.1, the length should be in units of 8 octets, including
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// the type and length fields.
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//
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// See https://datatracker.ietf.org/doc/html/rfc4861#section-4.6.1.
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srcLLAOptLen := len(lla) + 2
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// Make sure the value is rounded up to the nearest multiple of 8.
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srcLLAOptLenValue := (srcLLAOptLen + 7) / 8
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srcLLAPadLen := srcLLAOptLenValue*8 - srcLLAOptLen
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// TODO(a.garipov): Don't use a magic constant here. Refactor the code
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// and make all constants named instead of all those comments..
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data = make([]byte, 82+len(lla))
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// and make all constants named instead of all those comments.
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data = make([]byte, 80+srcLLAOptLen+srcLLAPadLen)
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i := 0
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// ICMPv6:
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@@ -175,12 +204,11 @@ func createICMPv6RAPacket(params icmpv6RA) (data []byte, err error) {
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// Option=Source link-layer address:
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data[i] = 1 // Type
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data[i+1] = 1 // Length
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data[i] = 1 // Type
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data[i+1] = byte(srcLLAOptLenValue) // Length
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i += 2
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copy(data[i:], lla) // Link-Layer Address[8/24]
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i += len(lla)
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i += len(lla) + srcLLAPadLen
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// Option=Recursive DNS Server:
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63
internal/dhcpd/routeradv_internal_test.go
Normal file
63
internal/dhcpd/routeradv_internal_test.go
Normal file
@@ -0,0 +1,63 @@
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package dhcpd
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import (
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"net"
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"testing"
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"github.com/google/gopacket"
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"github.com/google/gopacket/layers"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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func TestCreateICMPv6RAPacket(t *testing.T) {
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raConf := icmpv6RA{
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managedAddressConfiguration: false,
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otherConfiguration: true,
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mtu: 1500,
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prefix: net.ParseIP("1234::"),
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prefixLen: 64,
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recursiveDNSServer: net.ParseIP("fe80::800:27ff:fe00:0"),
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sourceLinkLayerAddress: []byte{0x0A, 0x00, 0x27, 0x00, 0x00, 0x00},
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}
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pkt, err := createICMPv6RAPacket(raConf)
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require.NoError(t, err)
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icmpPkt := &layers.ICMPv6{}
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err = icmpPkt.DecodeFromBytes(pkt, gopacket.NilDecodeFeedback)
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require.NoError(t, err)
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require.Equal(t, layers.LayerTypeICMPv6RouterAdvertisement, icmpPkt.NextLayerType())
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raPkt := &layers.ICMPv6RouterAdvertisement{}
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err = raPkt.DecodeFromBytes(icmpPkt.LayerPayload(), gopacket.NilDecodeFeedback)
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require.NoError(t, err)
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assert.Equal(t, raConf.managedAddressConfiguration, raPkt.ManagedAddressConfig())
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assert.Equal(t, raConf.otherConfiguration, raPkt.OtherConfig())
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wantOpts := layers.ICMPv6Options{{
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Type: layers.ICMPv6OptPrefixInfo,
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Data: []uint8{
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0x40, 0xC0, 0x00, 0x00, 0x0E, 0x10, 0x00, 0x00,
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0x0E, 0x10, 0x00, 0x00, 0x00, 0x00, 0x12, 0x34,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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},
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}, {
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Type: layers.ICMPv6OptMTU,
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Data: []uint8{0x00, 0x00, 0x00, 0x00, 0x05, 0xDC},
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}, {
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Type: layers.ICMPv6OptSourceAddress,
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Data: []uint8{0x0A, 0x00, 0x27, 0x00, 0x00, 0x0},
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}, {
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// Package layers declares no constant for Recursive DNS Server option.
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Type: layers.ICMPv6Opt(25),
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Data: []uint8{
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0x00, 0x00, 0x00, 0x00, 0x0E, 0x10, 0xFE, 0x80,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00,
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0x27, 0xFF, 0xFE, 0x00, 0x00, 0x00,
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},
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}}
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assert.Equal(t, wantOpts, raPkt.Options)
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}
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@@ -1,38 +0,0 @@
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package dhcpd
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import (
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"net"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestCreateICMPv6RAPacket(t *testing.T) {
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wantData := []byte{
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0x86, 0x00, 0x00, 0x00, 0x40, 0x40, 0x07, 0x08,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x03, 0x04, 0x40, 0xc0, 0x00, 0x00, 0x0e, 0x10,
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0x00, 0x00, 0x0e, 0x10, 0x00, 0x00, 0x00, 0x00,
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0x12, 0x34, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x05, 0x01, 0x00, 0x00, 0x00, 0x00, 0x05, 0xdc,
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0x01, 0x01, 0x0a, 0x00, 0x27, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x19, 0x03, 0x00, 0x00, 0x00, 0x00,
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0x0e, 0x10, 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x08, 0x00, 0x27, 0xff, 0xfe, 0x00,
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0x00, 0x00,
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}
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gotData, err := createICMPv6RAPacket(icmpv6RA{
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managedAddressConfiguration: false,
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otherConfiguration: true,
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mtu: 1500,
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prefix: net.ParseIP("1234::"),
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prefixLen: 64,
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recursiveDNSServer: net.ParseIP("fe80::800:27ff:fe00:0"),
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sourceLinkLayerAddress: []byte{0x0a, 0x00, 0x27, 0x00, 0x00, 0x00},
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})
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assert.NoError(t, err)
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assert.Equal(t, wantData, gotData)
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}
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