Moar Go

go/pkg/zerotier/nativetap.go

@@ -0,0 +1,137 @@
+/*
+ * Copyright (c)2019 ZeroTier, Inc.
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file in the project's root directory.
+ *
+ * Change Date: 2023-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2.0 of the Apache License.
+ */
+/****/
+
+package zerotier
+
+import (
+	"fmt"
+	"net"
+	"sync/atomic"
+	"unsafe"
+)
+
+//#cgo CFLAGS: -O3
+//#define ZT_CGO 1
+//#include <stdint.h>
+//#include <stdlib.h>
+//#include <string.h>
+//#include "../../native/GoGlue.h"
+import "C"
+
+// nativeTap is a Tap implementation that wraps a native C++ interface to a system tun/tap device
+type nativeTap struct {
+	tap           unsafe.Pointer
+	networkStatus uint32
+	enabled       uint32
+}
+
+// SetEnabled sets this tap's enabled state
+func (t *nativeTap) SetEnabled(enabled bool) {
+	if enabled && atomic.SwapUint32(&t.enabled, 1) == 0 {
+		C.ZT_GoTap_setEnabled(t.tap, 1)
+	} else if !enabled && atomic.SwapUint32(&t.enabled, 0) == 1 {
+		C.ZT_GoTap_setEnabled(t.tap, 0)
+	}
+}
+
+// Enabled returns true if this tap is currently processing packets
+func (t *nativeTap) Enabled() bool {
+	return atomic.LoadUint32(&t.enabled) != 0
+}
+
+// AddIP adds an IP address (with netmask) to this tap
+func (t *nativeTap) AddIP(ip net.IPNet) error {
+	bits, _ := ip.Mask.Size()
+	if len(ip.IP) == 16 {
+		if bits > 128 || bits < 0 {
+			return ErrInvalidParameter
+		}
+		C.ZT_GoTap_addIp(t.tap, afInet6, unsafe.Pointer(&ip.IP[0]), C.int(bits))
+	} else if len(ip.IP) == 4 {
+		if bits > 32 || bits < 0 {
+			return ErrInvalidParameter
+		}
+		C.ZT_GoTap_addIp(t.tap, afInet, unsafe.Pointer(&ip.IP[0]), C.int(bits))
+	}
+	return ErrInvalidParameter
+}
+
+// RemoveIP removes this IP address (with netmask) from this tap
+func (t *nativeTap) RemoveIP(ip net.IPNet) error {
+	bits, _ := ip.Mask.Size()
+	if len(ip.IP) == 16 {
+		if bits > 128 || bits < 0 {
+			return ErrInvalidParameter
+		}
+		C.ZT_GoTap_removeIp(t.tap, afInet6, unsafe.Pointer(&ip.IP[0]), C.int(bits))
+		return nil
+	}
+	if len(ip.IP) == 4 {
+		if bits > 32 || bits < 0 {
+			return ErrInvalidParameter
+		}
+		C.ZT_GoTap_removeIp(t.tap, afInet, unsafe.Pointer(&ip.IP[0]), C.int(bits))
+		return nil
+	}
+	return ErrInvalidParameter
+}
+
+// IPs returns IPs currently assigned to this tap (including externally or system-assigned IPs)
+func (t *nativeTap) IPs() (ips []net.IPNet, err error) {
+	defer func() {
+		e := recover()
+		if e != nil {
+			err = fmt.Errorf("%v", e)
+		}
+	}()
+	var ipbuf [16384]byte
+	count := int(C.ZT_GoTap_ips(t.tap, unsafe.Pointer(&ipbuf[0]), 16384))
+	ipptr := 0
+	for i := 0; i < count; i++ {
+		af := ipbuf[ipptr]
+		ipptr++
+		switch af {
+		case afInet:
+			var ip [4]byte
+			for j := 0; j < 4; j++ {
+				ip[j] = ipbuf[ipptr]
+				ipptr++
+			}
+			bits := ipbuf[ipptr]
+			ipptr++
+			ips = append(ips, net.IPNet{IP: net.IP(ip[:]), Mask: net.CIDRMask(int(bits), 32)})
+		case afInet6:
+			var ip [16]byte
+			for j := 0; j < 16; j++ {
+				ip[j] = ipbuf[ipptr]
+				ipptr++
+			}
+			bits := ipbuf[ipptr]
+			ipptr++
+			ips = append(ips, net.IPNet{IP: net.IP(ip[:]), Mask: net.CIDRMask(int(bits), 128)})
+		}
+	}
+	return
+}
+
+// DeviceName gets this tap's OS-specific device name
+func (t *nativeTap) DeviceName() string {
+	var dn [256]byte
+	C.ZT_GoTap_deviceName(t.tap, (*C.char)(unsafe.Pointer(&dn[0])))
+	for i, b := range dn {
+		if b == 0 {
+			return string(dn[0:i])
+		}
+	}
+	return ""
+}