working offers

leases/BUILD.bazel

@@ -0,0 +1,19 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "leases",
+    srcs = [
+        "hardware_address.go",
+        "lease_info.go",
+        "server_info.go",
+    ],
+    importpath = "git.wntrmute.dev/kyle/kdhcp/leases",
+    visibility = ["//visibility:public"],
+)
+
+go_test(
+    name = "leases_test",
+    size = "small",
+    srcs = ["hardware_address_test.go"],
+    embed = [":leases"],
+)

leases/hardware_address.go

@@ -0,0 +1,41 @@
+package leases
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+type HardwareAddress []byte
+
+func (mac HardwareAddress) String() string {
+	marshalled := []string{}
+	for i := 0; i < len(mac); i++ {
+		marshalled = append(marshalled, fmt.Sprintf("%02x", []byte(mac[i:i+1])))
+	}
+
+	return strings.Join(marshalled, ":")
+}
+
+func (mac HardwareAddress) MarshalText() ([]byte, error) {
+	return []byte(mac.String()), nil
+}
+
+func (mac *HardwareAddress) UnmarshalText(b []byte) error {
+	rb := bytes.Split(b, []byte(":"))
+	for _, octet := range rb {
+		n, err := strconv.ParseUint(string(octet), 16, 8)
+		if err != nil {
+			return err
+		}
+
+		*mac = append(*mac, uint8(n))
+	}
+
+	return nil
+}
+
+func (mac HardwareAddress) Match(other HardwareAddress) bool {
+	return bytes.Equal(mac, other)
+}

leases/hardware_address_test.go

@@ -0,0 +1,31 @@
+package leases
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestHardwareMacMarshalling(t *testing.T) {
+	macString := "b8:27:eb:b6:a1:a7"
+	mac := HardwareAddress([]byte{0xb8, 0x27, 0xeb, 0xb6, 0xa1, 0xa7})
+
+	b, err := mac.MarshalText()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s := string(b)
+	if s != macString {
+		t.Fatalf("have %s, want %s", s, macString)
+	}
+
+	mac2 := &HardwareAddress{}
+	err = mac2.UnmarshalText(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !bytes.Equal(*mac2, mac) {
+		t.Fatalf("have %x, want %x", *mac2, mac)
+	}
+}

leases/lease_info.go

@@ -0,0 +1,73 @@
+package leases
+
+import (
+	"fmt"
+	"net/netip"
+	"sort"
+	"strings"
+	"time"
+)
+
+type Info struct {
+	HostName        string          `yaml:"hostname" json:"hostname,omitempty"`
+	Addr            netip.Addr      `yaml:"addr" json:"addr,omitempty"`
+	HardwareAddress HardwareAddress `yaml:"mac_addr" json:"hardware_address,omitempty"`
+	Expires         time.Time       `yaml:"expires" json:"expires,omitempty"`
+}
+
+func (li *Info) String() string {
+	return fmt.Sprintf("lease[hostname=%s addr=%s hw=%s expires=%s]", li.HostName, li.Addr, li.HardwareAddress, li.Expires)
+}
+
+type sortableLease []*Info
+
+func (a sortableLease) Len() int           { return len(a) }
+func (a sortableLease) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a sortableLease) Less(i, j int) bool { return a[i].Addr.Less(a[j].Addr) }
+
+func (li *Info) ResetExpiry(t time.Time, dur time.Duration) {
+	li.Expires = t.Add(dur)
+}
+
+func (li *Info) IsExpired(t time.Time) bool {
+	return t.After(li.Expires)
+}
+
+func (li *Info) Expire() {
+	li.Expires = time.Time{}
+}
+
+func Sort(leases []*Info) []*Info {
+	sortable := sortableLease(leases)
+	sort.Sort(sortable)
+
+	return []*Info(sortable)
+}
+
+func (lease *Info) Reset() *Info {
+	lease.Expires = time.Time{}
+	lease.HardwareAddress = nil
+	return lease
+}
+
+func (lease Info) Compare(other Info) error {
+	susFields := []string{}
+
+	if lease.Addr != other.Addr {
+		susFields = append(susFields, fmt.Sprintf("address is %s, but is recorded as %s", lease.Addr, other.Addr))
+	}
+
+	if !lease.HardwareAddress.Match(other.HardwareAddress) {
+		susFields = append(susFields, fmt.Sprintf("hardware address is %s, but is recorded as %s", lease.HardwareAddress, other.HardwareAddress))
+	}
+
+	if lease.HostName != other.HostName {
+		susFields = append(susFields, fmt.Sprintf("hostname is %s, but is recorded as %s", lease.HostName, other.HostName))
+	}
+
+	if len(susFields) > 0 {
+		return fmt.Errorf("suspicious lease: %s", strings.Join(susFields, ";"))
+	}
+
+	return nil
+}

leases/server_info.go

@@ -0,0 +1,17 @@
+package leases
+
+import "net/netip"
+
+type Server struct {
+	Addr            netip.Addr
+	HardwareAddress HardwareAddress
+	Network         *Network
+}
+
+type Network struct {
+	Mask      netip.Addr
+	Gateway   netip.Addr
+	Broadcast netip.Addr
+	Domain    string
+	DNS       []netip.Addr
+}