Merge branch 'master' into travis_build_macos

Author: insomniacslk

.gitignore

@@ -1 +1,4 @@
 .*.swp
+examples/client6/client6
+examples/client4/client4
+examples/packetcrafting6/packetcrafting6

.travis/tests.sh

@@ -28,7 +28,7 @@ done
 
 # Skip go1.9 for this check. rtr7/router7 depends on miekg/dns, which does not
 # support go1.9
-if [ "$TRAVIS_GO_VERSION" = "1.9" ]
+if [[ "$TRAVIS_GO_VERSION" =~ ^1.(9|10|11)$ ]]
 then
     exit 0
 fi

CONTRIBUTORS.md

@@ -5,3 +5,4 @@
 * Sean Karlage (BSDP package, and of tons of improvements to the DHCPv4 package)
 * Owen Mooney (several option fixes and modifiers)
 * Mikolaj Walczak (asynchronous DHCPv6 client)
+* Chris Koch (tons of improvements in DHCPv4 and DHCPv6 internals and interface)

README.md

@@ -31,199 +31,15 @@ go get -u github.com/insomniacslk/dhcp/dhcpv{4,6}
 The sections below will illustrate how to use the `dhcpv6` and `dhcpv4`
 packages.
 
-See more example code at https://github.com/insomniacslk/exdhcp
-
-
-## DHCPv6 client
-
-To run a DHCPv6 transaction on the interface "eth0":
-
-```go
-package main
-
-import (
-	"log"
-
-	"github.com/insomniacslk/dhcp/dhcpv6"
-)
-
-
-func main() {
-	// NewClient sets up a new DHCPv6 client with default values
-	// for read and write timeouts, for destination address and listening
-	// address
-	client := dhcpv6.NewClient()
-
-	// Exchange runs a Solicit-Advertise-Request-Reply transaction on the
-	// specified network interface, and returns a list of DHCPv6 packets
-	// (a "conversation") and an error if any. Notice that Exchange may
-	// return a non-empty packet list even if there is an error. This is
-	// intended, because the transaction may fail at any point, and we
-	// still want to know what packets were exchanged until then.
-	// A default Solicit packet will be used during the "conversation",
-	// which can be manipulated by using modifiers.
-	conversation, err := client.Exchange("eth0")
-
-	// Summary() prints a verbose representation of the exchanged packets.
-	for _, packet := range conversation {
-		log.Print(packet.Summary())
-	}
-	// error handling is done *after* printing, so we still print the
-	// exchanged packets if any, as explained above.
-	if err != nil {
-		log.Fatal(err)
-	}
-}
-```
-
-
-## DHCPv6 packet crafting and manipulation
-
-```go
-package main
-
-import (
-	"log"
-	"net"
-
-	"github.com/insomniacslk/dhcp/dhcpv6"
-	"github.com/insomniacslk/dhcp/iana"
-)
-
-func main() {
-	// In this example we create and manipulate a DHCPv6 solicit packet
-	// and encapsulate it in a relay packet. To to this, we use
-	// `dhcpv6.DHCPv6Message` and `dhcpv6.DHCPv6Relay`, two structures
-	// that implement the `dhcpv6.DHCPv6` interface.
-	// Then print the wire-format representation of the packet.
-
-	// Create the DHCPv6 Solicit first, using the interface "eth0"
-	// to get the MAC address
-	msg, err := dhcpv6.NewSolicitForInterface("eth0")
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	// In this example I want to redact the MAC address of my
-	// network interface, so instead of replacing it manually,
-	// I will show how to use modifiers for the purpose.
-	// A Modifier is simply a function that can be applied on
-	// a DHCPv6 object to manipulate it. Here we use it to
-	// replace the MAC address with a dummy one.
-	// Modifiers can be passed to many functions, for example
-	// to constructors, `Exchange()`, `Solicit()`, etc. Check
-	// the source code to know where to use them.
-	// Existing modifiers are implemented in dhcpv6/modifiers.go .
-	mac, err := net.ParseMAC("00:fa:ce:b0:0c:00")
-	if err != nil {
-		log.Fatal(err)
-	}
-	duid := dhcpv6.Duid{
-		Type:          dhcpv6.DUID_LLT,
-		HwType:        iana.HwTypeEthernet,
-		Time:          dhcpv6.GetTime(),
-		LinkLayerAddr: mac,
-	}
-	// As suggested above, an alternative is to call
-	// dhcpv6.NewSolicitForInterface("eth0", dhcpv6.WithCLientID(duid))
-	msg = dhcpv6.WithClientID(duid)(msg)
-
-	// Now encapsulate the message in a DHCPv6 relay.
-	// As per RFC3315, the link-address and peer-address have
-	// to be set by the relay agent. We use dummy values here.
-	linkAddr := net.ParseIP("2001:0db8::1")
-	peerAddr := net.ParseIP("2001:0db8::2")
-	relay, err := dhcpv6.EncapsulateRelay(msg, dhcpv6.MessageTypeRelayForward, linkAddr, peerAddr)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	// Print a verbose representation of the relay packet, that will also
-	// show a short representation of the inner Solicit message.
-	// To print a detailed summary of the inner packet, extract it
-	// first from the relay using `relay.GetInnerMessage()`.
-	log.Print(relay.Summary())
-
-	// And finally, print the bytes that would be sent on the wire
-	log.Print(relay.ToBytes())
+* [dhcpv6 client](examples/client6/)
+* [dhcpv6 server](examples/server6/)
+* [dhcpv6 packet crafting](examples/packetcrafting6)
+* TODO dhcpv4 client
+* TODO dhcpv4 server
+* TODO dhcpv4 packet crafting
 
-	// Note: there are many more functions in the library, check them
-	// out in the source code. For example, if you want to decode a
-	// byte stream into a DHCPv6 message or relay, you can use
-	// `dhcpv6.FromBytes`.
-}
-```
-
-The output (slightly modified for readability) is
-```
-$ go run main.go
-2018/11/08 13:56:31 DHCPv6Relay
-  messageType=RELAY-FORW
-  hopcount=0
-  linkaddr=2001:db8::1
-  peeraddr=2001:db8::2
-  options=[OptRelayMsg{relaymsg=DHCPv6Message(messageType=SOLICIT transactionID=0x9e0242, 4 options)}]
-
-2018/11/08 13:56:31 [12 0 32 1 13 184 0 0 0 0 0 0 0 0 0 0 0 1 32 1 13 184
-                     0 0 0 0 0 0 0 0 0 0 0 2 0 9 0 52 1 158 2 66 0 1 0 14
-                     0 1 0 1 35 118 253 15 0 250 206 176 12 0 0 6 0 4 0 23
-                     0 24 0 8 0 2 0 0 0 3 0 12 250 206 176 12 0 0 14 16 0
-                     0 21 24]
-```
-
-## DHCPv6 server
-
-A DHCPv6 server requires the user to implement a request handler. Basically the
-user has to provide the logic to answer to each packet. The library offers a few
-facilities to forge response packets, e.g. `NewAdvertiseFromSolicit`,
-`NewReplyFromDHCPv6Message` and so on. Look at the source code to see what's
-available.
-
-An example server that will print (but not reply to) the client's request is
-shown below:
-
-```go
-package main
-
-import (
-        "log"
-        "net"
-
-        "github.com/insomniacslk/dhcp/dhcpv6"
-)
-
-func handler(conn net.PacketConn, peer net.Addr, m dhcpv6.DHCPv6) {
-        // this function will just print the received DHCPv6 message, without replying
-        log.Print(m.Summary())
-}
 
-func main() {
-        laddr := net.UDPAddr{
-                IP:   net.ParseIP("::1"),
-                Port: dhcpv6.DefaultServerPort,
-        }
-        server := dhcpv6.NewServer(laddr, handler)
-
-        defer server.Close()
-        if err := server.ActivateAndServe(); err != nil {
-                log.Panic(err)
-        }
-}
-```
-
-## DHCPv4 client
-
-TODO
-
-
-## DHCPv4 packet parsing
-
-TODO
-
-
-## DHCPv4 server
-
-TODO
+See more example code at https://github.com/insomniacslk/exdhcp
 
 
 # Public projects that use it
@@ -235,3 +51,4 @@ TODO
 * Bender from Pinterest, a library for load-testing, https://github.com/pinterest/bender
 * FBender from Facebook, a tool for load-testing based on Bender, https://github.com/facebookincubator/fbender
 * CoreDHCP, a fast, multithreaded, modular and extensible DHCP server, https://github.com/coredhcp/coredhcp
+* u-root, an embeddable root file system, https://github.com/u-root/u-root

dhcpv4/async/client.go

@@ -7,8 +7,9 @@ import (
 	"sync"
 	"time"
 
-	"github.com/fanliao/go-promise"
+	promise "github.com/fanliao/go-promise"
 	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/insomniacslk/dhcp/dhcpv4/client4"
 )
 
 // Default ports
@@ -41,8 +42,8 @@ type Client struct {
 // NewClient creates an asynchronous client
 func NewClient() *Client {
 	return &Client{
-		ReadTimeout:  dhcpv4.DefaultReadTimeout,
-		WriteTimeout: dhcpv4.DefaultWriteTimeout,
+		ReadTimeout:  client4.DefaultReadTimeout,
+		WriteTimeout: client4.DefaultWriteTimeout,
 	}
 }
 
@@ -159,7 +160,7 @@ func (c *Client) receive(_ *dhcpv4.DHCPv4) {
 
 	c.connection.SetReadDeadline(time.Now().Add(c.ReadTimeout))
 	for {
-		buffer := make([]byte, dhcpv4.MaxUDPReceivedPacketSize)
+		buffer := make([]byte, client4.MaxUDPReceivedPacketSize)
 		n, _, _, _, err := c.connection.ReadMsgUDP(buffer, oobdata)
 		if err != nil {
 			if err, ok := err.(net.Error); !ok || !err.Timeout() {
@@ -196,7 +197,7 @@ func (c *Client) remoteAddr() (*net.UDPAddr, error) {
 // Returns a future which resolves to response and error.
 func (c *Client) Send(message *dhcpv4.DHCPv4, modifiers ...dhcpv4.Modifier) *promise.Future {
 	for _, mod := range modifiers {
-		message = mod(message)
+		mod(message)
 	}
 
 	p := promise.NewPromise()

dhcpv4/async/client_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/insomniacslk/dhcp/dhcpv4/client4"
 	"github.com/stretchr/testify/require"
 )
 
@@ -19,7 +20,7 @@ func serve(ctx context.Context, addr *net.UDPAddr, response *dhcpv4.DHCPv4) erro
 	go func() {
 		defer conn.Close()
 		oobdata := []byte{}
-		buffer := make([]byte, dhcpv4.MaxUDPReceivedPacketSize)
+		buffer := make([]byte, client4.MaxUDPReceivedPacketSize)
 		for {
 			select {
 			case <-ctx.Done():
@@ -48,8 +49,8 @@ func serve(ctx context.Context, addr *net.UDPAddr, response *dhcpv4.DHCPv4) erro
 func TestNewClient(t *testing.T) {
 	c := NewClient()
 	require.NotNil(t, c)
-	require.Equal(t, c.ReadTimeout, dhcpv4.DefaultReadTimeout)
-	require.Equal(t, c.ReadTimeout, dhcpv4.DefaultWriteTimeout)
+	require.Equal(t, c.ReadTimeout, client4.DefaultReadTimeout)
+	require.Equal(t, c.ReadTimeout, client4.DefaultWriteTimeout)
 }
 
 func TestOpenInvalidAddrFailes(t *testing.T) {

dhcpv4/bindtodevice_bsd.go

@@ -0,0 +1,18 @@
+// +build freebsd openbsd netbsd
+
+package dhcpv4
+
+import (
+	"net"
+	"syscall"
+)
+
+// BindToInterface emulates linux's SO_BINDTODEVICE option for a socket by using
+// IP_RECVIF.
+func BindToInterface(fd int, ifname string) error {
+	iface, err := net.InterfaceByName(ifname)
+	if err != nil {
+		return err
+	}
+	return syscall.SetsockoptInt(fd, syscall.IPPROTO_IP, syscall.IP_RECVIF, iface.Index)
+}

dhcpv4/bsdp/boot_image.go

@@ -3,6 +3,7 @@ package bsdp
 import (
 	"fmt"
 
+	"github.com/insomniacslk/dhcp/dhcpv4"
 	"github.com/u-root/u-root/pkg/uio"
 )
 
@@ -18,9 +19,9 @@ const (
 	// 4 - 127 are reserved for future use.
 )
 
-// BootImageTypeToString maps the different BootImageTypes to human-readable
+// bootImageTypeToString maps the different BootImageTypes to human-readable
 // representations.
-var BootImageTypeToString = map[BootImageType]string{
+var bootImageTypeToString = map[BootImageType]string{
 	BootImageTypeMacOS9:              "macOS 9",
 	BootImageTypeMacOSX:              "macOS",
 	BootImageTypeMacOSXServer:        "macOS Server",
@@ -35,6 +36,16 @@ type BootImageID struct {
 	Index     uint16
 }
 
+// ToBytes implements dhcpv4.OptionValue.
+func (b BootImageID) ToBytes() []byte {
+	return uio.ToBigEndian(b)
+}
+
+// FromBytes reads data into b.
+func (b *BootImageID) FromBytes(data []byte) error {
+	return uio.FromBigEndian(b, data)
+}
+
 // Marshal writes the binary representation to buf.
 func (b BootImageID) Marshal(buf *uio.Lexer) {
 	var byte0 byte
@@ -55,7 +66,7 @@ func (b BootImageID) String() string {
 	} else {
 		s += " uninstallable"
 	}
-	t, ok := BootImageTypeToString[b.ImageType]
+	t, ok := bootImageTypeToString[b.ImageType]
 	if !ok {
 		t = "unknown"
 	}
@@ -99,3 +110,27 @@ func (b *BootImage) Unmarshal(buf *uio.Lexer) error {
 	b.Name = string(buf.Consume(int(nameLength)))
 	return buf.Error()
 }
+
+func getBootImageID(code dhcpv4.OptionCode, o dhcpv4.Options) *BootImageID {
+	v := o.Get(code)
+	if v == nil {
+		return nil
+	}
+	var b BootImageID
+	if err := uio.FromBigEndian(&b, v); err != nil {
+		return nil
+	}
+	return &b
+}
+
+// OptDefaultBootImageID returns a new default boot image ID option as per
+// BSDP.
+func OptDefaultBootImageID(b BootImageID) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionDefaultBootImageID, Value: b}
+}
+
+// OptSelectedBootImageID returns a new selected boot image ID option as per
+// BSDP.
+func OptSelectedBootImageID(b BootImageID) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionSelectedBootImageID, Value: b}
+}