conf: introduce configuration management

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 180 insertions, 0 deletions

diff --git a/conf/config.go b/conf/config.go
new file mode 100644
index 00000000..a321bc0c
--- /dev/null
+++ b/conf/config.go
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package conf
+
+import (
+	"crypto/rand"
+	"crypto/subtle"
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"net"
+	"strings"
+	"time"
+
+	"golang.org/x/crypto/curve25519"
+)
+
+const KeyLength = 32
+
+type IPCidr struct {
+	IP   net.IP
+	Cidr uint8
+}
+
+type Endpoint struct {
+	Host string
+	Port uint16
+}
+
+type Key [KeyLength]byte
+type HandshakeTime time.Duration
+type Bytes uint64
+
+type Config struct {
+	Name      string
+	Interface Interface
+	Peers     []Peer
+}
+
+type Interface struct {
+	PrivateKey Key
+	Addresses  []IPCidr
+	ListenPort uint16
+	Mtu        uint16
+	Dns        []net.IP
+}
+
+type Peer struct {
+	PublicKey           Key
+	PresharedKey        Key
+	AllowedIPs          []IPCidr
+	Endpoint            Endpoint
+	PersistentKeepalive uint16
+
+	RxBytes           Bytes
+	TxBytes           Bytes
+	LastHandshakeTime HandshakeTime
+}
+
+func (r *IPCidr) String() string {
+	return fmt.Sprintf("%s/%d", r.IP.String(), r.Cidr)
+}
+
+func (e *Endpoint) String() string {
+	if strings.IndexByte(e.Host, ':') > 0 {
+		return fmt.Sprintf("[%s]:%d", e.Host, e.Port)
+	}
+	return fmt.Sprintf("%s:%d", e.Host, e.Port)
+}
+
+func (e *Endpoint) IsEmpty() bool {
+	return len(e.Host) == 0
+}
+
+func (k *Key) String() string {
+	return base64.StdEncoding.EncodeToString(k[:])
+}
+
+func (k *Key) HexString() string {
+	return hex.EncodeToString(k[:])
+}
+
+func (k *Key) IsZero() bool {
+	var zeros Key
+	return subtle.ConstantTimeCompare(zeros[:], k[:]) == 1
+}
+
+func (k *Key) Public() *Key {
+	var p [KeyLength]byte
+	curve25519.ScalarBaseMult(&p, (*[KeyLength]byte)(k))
+	return (*Key)(&p)
+}
+
+func NewPresharedKey() (*Key, error) {
+	var k [KeyLength]byte
+	_, err := rand.Read(k[:])
+	if err != nil {
+		return nil, err
+	}
+	return (*Key)(&k), nil
+}
+
+func NewPrivateKey() (*Key, error) {
+	k, err := NewPresharedKey()
+	if err != nil {
+		return nil, err
+	}
+	k[0] &= 248
+	k[31] = (k[31] & 127) | 64
+	return k, nil
+}
+
+func formatInterval(i int64, n string, l int) string {
+	r := ""
+	if l > 0 {
+		r += ", "
+	}
+	r += fmt.Sprintf("%d %s", i, n)
+	if i != 1 {
+		r += "s"
+	}
+	return r
+}
+
+func (t HandshakeTime) IsEmpty() bool {
+	return t == HandshakeTime(0)
+}
+
+func (t HandshakeTime) String() string {
+	u := time.Unix(0, 0).Add(time.Duration(t)).Unix()
+	n := time.Now().Unix()
+	if u == n {
+		return "Now"
+	} else if u > n {
+		return "System clock wound backward!"
+	}
+	left := n - u
+	years := left / (365 * 24 * 60 * 60)
+	left = left % (365 * 24 * 60 * 60)
+	days := left / (24 * 60 * 60)
+	left = left % (24 * 60 * 60)
+	hours := left / (60 * 60)
+	left = left % (60 * 60)
+	minutes := left / 60
+	seconds := left % 60
+	s := ""
+	if years > 0 {
+		s += formatInterval(years, "year", len(s))
+	}
+	if days > 0 {
+		s += formatInterval(days, "day", len(s))
+	}
+	if hours > 0 {
+		s += formatInterval(hours, "hour", len(s))
+	}
+	if minutes > 0 {
+		s += formatInterval(minutes, "minute", len(s))
+	}
+	if seconds > 0 {
+		s += formatInterval(seconds, "second", len(s))
+	}
+	s += " ago"
+	return s
+}
+
+func (b Bytes) String() string {
+	if b < 1024 {
+		return fmt.Sprintf("%d B", b)
+	} else if b < 1024*1024 {
+		return fmt.Sprintf("%.2f KiB", float64(b)/1024)
+	} else if b < 1024*1024*1024 {
+		return fmt.Sprintf("%.2f MiB", float64(b)/(1024*1024))
+	} else if b < 1024*1024*1024*1024 {
+		return fmt.Sprintf("%.2f GiB", float64(b)/(1024*1024*1024))
+	}
+	return fmt.Sprintf("%.2f TiB", float64(b)/(1024*1024*1024)/1024)
+}