1 files changed, 109 insertions, 0 deletions
diff --git a/dhcpv4/option_archtype.go b/dhcpv4/option_archtype.go
new file mode 100644
index 0000000..16ca98d
--- /dev/null
+++ b/dhcpv4/option_archtype.go
@@ -0,0 +1,109 @@
+package dhcpv4
+
+// This option implements the Client System Architecture Type option
+// https://tools.ietf.org/html/rfc4578
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+//ArchType encodes an architecture type in an uint16
+type ArchType uint16
+
+// see rfc4578
+const (
+	INTEL_X86PC       ArchType = 0
+	NEC_PC98          ArchType = 1
+	EFI_ITANIUM       ArchType = 2
+	DEC_ALPHA         ArchType = 3
+	ARC_X86           ArchType = 4
+	INTEL_LEAN_CLIENT ArchType = 5
+	EFI_IA32          ArchType = 6
+	EFI_BC            ArchType = 7
+	EFI_XSCALE        ArchType = 8
+	EFI_X86_64        ArchType = 9
+)
+
+// ArchTypeToStringMap maps an ArchType to a mnemonic name
+var ArchTypeToStringMap = map[ArchType]string{
+	INTEL_X86PC:       "Intel x86PC",
+	NEC_PC98:          "NEC/PC98",
+	EFI_ITANIUM:       "EFI Itanium",
+	DEC_ALPHA:         "DEC Alpha",
+	ARC_X86:           "Arc x86",
+	INTEL_LEAN_CLIENT: "Intel Lean Client",
+	EFI_IA32:          "EFI IA32",
+	EFI_BC:            "EFI BC",
+	EFI_XSCALE:        "EFI Xscale",
+	EFI_X86_64:        "EFI x86-64",
+}
+
+// OptClientArchType represents an option encapsulating the Client System
+// Architecture Type option Definition.
+type OptClientArchType struct {
+	ArchTypes []ArchType
+}
+
+// Code returns the option code.
+func (o *OptClientArchType) Code() OptionCode {
+	return OptionClientSystemArchitectureType
+}
+
+// ToBytes returns a serialized stream of bytes for this option.
+func (o *OptClientArchType) ToBytes() []byte {
+	ret := []byte{byte(o.Code()), byte(o.Length())}
+	for _, at := range o.ArchTypes {
+		buf := make([]byte, 2)
+		binary.BigEndian.PutUint16(buf[0:2], uint16(at))
+		ret = append(ret, buf...)
+	}
+	return ret
+}
+
+// Length returns the length of the data portion (excluding option code an byte
+// length).
+func (o *OptClientArchType) Length() int {
+	return 2*len(o.ArchTypes)
+}
+
+// String returns a human-readable string.
+func (o *OptClientArchType) String() string {
+	var archTypes string
+	for idx, at := range o.ArchTypes {
+		name, ok := ArchTypeToStringMap[at]
+		if !ok {
+			name = "Unknown"
+		}
+		archTypes += name
+		if idx < len(o.ArchTypes)-1 {
+			archTypes += ", "
+		}
+	}
+	return fmt.Sprintf("Client System Architecture Type -> %v", archTypes)
+}
+
+// ParseOptClientArchType returns a new OptClientArchType from a byte stream,
+// or error if any.
+func ParseOptClientArchType(data []byte) (*OptClientArchType, error) {
+	if len(data) < 2 {
+		return nil, ErrShortByteStream
+	}
+	code := OptionCode(data[0])
+	if code != OptionClientSystemArchitectureType {
+		return nil, fmt.Errorf("expected code %v, got %v", OptionClientSystemArchitectureType, code)
+	}
+	length := int(data[1])
+	if length == 0 || length%2 != 0 {
+		return nil, fmt.Errorf("Invalid length: expected multiple of 2 larger than 2, got %v", length)
+	}
+	if len(data) < 2+length {
+		return nil, ErrShortByteStream
+	}
+	archTypes := make([]ArchType, 0, length%2)
+	for idx := 0; idx < length; idx += 2 {
+		b := data[2+idx : 2+idx+2]
+		archTypes = append(archTypes, ArchType(binary.BigEndian.Uint16(b)))
+	}
+	return &OptClientArchType{ArchTypes: archTypes}, nil
+}