dhcpv4: nicer API for option parsing.

From:
  r := d.GetOneOption(OptionRouter).(*OptRouter).Routers
  d.UpdateOption(&OptRouter{Routers: []net.IP{net.IP{192, 168, 0, 1}}})

To:
  r := GetRouter(d.Options)
  d.UpdateOption(OptRouter(net.IP{192, 168, 0, 1}, ...))

1 files changed, 99 insertions, 0 deletions

diff --git a/dhcpv4/bsdp/bsdp_option_misc.go b/dhcpv4/bsdp/bsdp_option_misc.go
new file mode 100644
index 0000000..2d3a7bf
--- /dev/null
+++ b/dhcpv4/bsdp/bsdp_option_misc.go
@@ -0,0 +1,99 @@
+package bsdp
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/u-root/u-root/pkg/uio"
+)
+
+// OptReplyPort returns a new BSDP reply port option.
+//
+// Implements the BSDP option reply port. This is used when BSDP responses
+// should be sent to a reply port other than the DHCP default. The macOS GUI
+// "Startup Disk Select" sends this option since it's operating in an
+// unprivileged context.
+func OptReplyPort(port uint16) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionReplyPort, Value: dhcpv4.Uint16(port)}
+}
+
+// GetReplyPort returns the BSDP reply port in o, if present.
+func GetReplyPort(o dhcpv4.Options) (uint16, error) {
+	return dhcpv4.GetUint16(OptionReplyPort, o)
+}
+
+// OptServerPriority returns a new BSDP server priority option.
+func OptServerPriority(prio uint16) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionServerPriority, Value: dhcpv4.Uint16(prio)}
+}
+
+// GetServerPriority returns the BSDP server priority in o if present.
+func GetServerPriority(o dhcpv4.Options) (uint16, error) {
+	return dhcpv4.GetUint16(OptionServerPriority, o)
+}
+
+// OptMachineName returns a BSDP Machine Name option.
+func OptMachineName(name string) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionMachineName, Value: dhcpv4.String(name)}
+}
+
+// GetMachineName finds and parses the BSDP Machine Name option from o.
+func GetMachineName(o dhcpv4.Options) string {
+	return dhcpv4.GetString(OptionMachineName, o)
+}
+
+// Version is the BSDP protocol version. Can be one of 1.0 or 1.1.
+type Version [2]byte
+
+// Specific versions.
+var (
+	Version1_0 = Version{1, 0}
+	Version1_1 = Version{1, 1}
+)
+
+// ToBytes returns a serialized stream of bytes for this option.
+func (o Version) ToBytes() []byte {
+	return o[:]
+}
+
+// String returns a human-readable string for this option.
+func (o Version) String() string {
+	return fmt.Sprintf("%d.%d", o[0], o[1])
+}
+
+// FromBytes constructs a Version struct from a sequence of
+// bytes and returns it, or an error.
+func (o *Version) FromBytes(data []byte) error {
+	buf := uio.NewBigEndianBuffer(data)
+	buf.ReadBytes(o[:])
+	return buf.FinError()
+}
+
+// OptVersion returns a new BSDP version option.
+func OptVersion(version Version) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionVersion, Value: version}
+}
+
+// GetVersion returns the BSDP version in o if present.
+func GetVersion(o dhcpv4.Options) (Version, error) {
+	v := o.Get(OptionVersion)
+	if v == nil {
+		return Version{0, 0}, fmt.Errorf("version not found")
+	}
+	var ver Version
+	if err := ver.FromBytes(v); err != nil {
+		return Version{0, 0}, err
+	}
+	return ver, nil
+}
+
+// GetServerIdentifier returns the BSDP Server Identifier value in o.
+func GetServerIdentifier(o dhcpv4.Options) net.IP {
+	return dhcpv4.GetIP(OptionServerIdentifier, o)
+}
+
+// OptServerIdentifier returns a new BSDP Server Identifier option.
+func OptServerIdentifier(ip net.IP) dhcpv4.Option {
+	return dhcpv4.Option{Code: OptionServerIdentifier, Value: dhcpv4.IP(ip)}
+}