Refactoring: move tuntap and icmpv6 into separate package

src/tuntap/tun_bsd.go

@@ -0,0 +1,171 @@
+// +build openbsd freebsd netbsd
+
+package tuntap
+
+import (
+	"encoding/binary"
+	"os/exec"
+	"strconv"
+	"strings"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/yggdrasil-network/water"
+)
+
+const SIOCSIFADDR_IN6 = (0x80000000) | ((288 & 0x1fff) << 16) | uint32(byte('i'))<<8 | 12
+
+type in6_addrlifetime struct {
+	ia6t_expire    float64
+	ia6t_preferred float64
+	ia6t_vltime    uint32
+	ia6t_pltime    uint32
+}
+
+type sockaddr_in6 struct {
+	sin6_len      uint8
+	sin6_family   uint8
+	sin6_port     uint8
+	sin6_flowinfo uint32
+	sin6_addr     [8]uint16
+	sin6_scope_id uint32
+}
+
+/*
+from <netinet6/in6_var.h>
+struct  in6_ifreq {
+ 277         char    ifr_name[IFNAMSIZ];
+ 278         union {
+ 279                 struct  sockaddr_in6 ifru_addr;
+ 280                 struct  sockaddr_in6 ifru_dstaddr;
+ 281                 int     ifru_flags;
+ 282                 int     ifru_flags6;
+ 283                 int     ifru_metric;
+ 284                 caddr_t ifru_data;
+ 285                 struct in6_addrlifetime ifru_lifetime;
+ 286                 struct in6_ifstat ifru_stat;
+ 287                 struct icmp6_ifstat ifru_icmp6stat;
+ 288                 u_int32_t ifru_scope_id[16];
+ 289         } ifr_ifru;
+ 290 };
+*/
+
+type in6_ifreq_mtu struct {
+	ifr_name [syscall.IFNAMSIZ]byte
+	ifru_mtu int
+}
+
+type in6_ifreq_addr struct {
+	ifr_name  [syscall.IFNAMSIZ]byte
+	ifru_addr sockaddr_in6
+}
+
+type in6_ifreq_flags struct {
+	ifr_name [syscall.IFNAMSIZ]byte
+	flags    int
+}
+
+type in6_ifreq_lifetime struct {
+	ifr_name          [syscall.IFNAMSIZ]byte
+	ifru_addrlifetime in6_addrlifetime
+}
+
+// Sets the IPv6 address of the utun adapter. On all BSD platforms (FreeBSD,
+// OpenBSD, NetBSD) an attempt is made to set the adapter properties by using
+// a system socket and making syscalls to the kernel. This is not refined though
+// and often doesn't work (if at all), therefore if a call fails, it resorts
+// to calling "ifconfig" instead.
+func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+	var config water.Config
+	if ifname[:4] == "auto" {
+		ifname = "/dev/tap0"
+	}
+	if len(ifname) < 9 {
+		panic("TUN/TAP name must be in format /dev/tunX or /dev/tapX")
+	}
+	switch {
+	case iftapmode || ifname[:8] == "/dev/tap":
+		config = water.Config{DeviceType: water.TAP}
+	case !iftapmode || ifname[:8] == "/dev/tun":
+		panic("TUN mode is not currently supported on this platform, please use TAP instead")
+	default:
+		panic("TUN/TAP name must be in format /dev/tunX or /dev/tapX")
+	}
+	config.Name = ifname
+	iface, err := water.New(config)
+	if err != nil {
+		panic(err)
+	}
+	tun.iface = iface
+	tun.mtu = getSupportedMTU(mtu)
+	return tun.setupAddress(addr)
+}
+
+func (tun *TunAdapter) setupAddress(addr string) error {
+	var sfd int
+	var err error
+
+	// Create system socket
+	if sfd, err = unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0); err != nil {
+		tun.core.log.Printf("Create AF_INET socket failed: %v.", err)
+		return err
+	}
+
+	// Friendly output
+	tun.core.log.Infof("Interface name: %s", tun.iface.Name())
+	tun.core.log.Infof("Interface IPv6: %s", addr)
+	tun.core.log.Infof("Interface MTU: %d", tun.mtu)
+
+	// Create the MTU request
+	var ir in6_ifreq_mtu
+	copy(ir.ifr_name[:], tun.iface.Name())
+	ir.ifru_mtu = int(tun.mtu)
+
+	// Set the MTU
+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(sfd), uintptr(syscall.SIOCSIFMTU), uintptr(unsafe.Pointer(&ir))); errno != 0 {
+		err = errno
+		tun.core.log.Errorf("Error in SIOCSIFMTU: %v", errno)
+
+		// Fall back to ifconfig to set the MTU
+		cmd := exec.Command("ifconfig", tun.iface.Name(), "mtu", string(tun.mtu))
+		tun.core.log.Warnf("Using ifconfig as fallback: %v", strings.Join(cmd.Args, " "))
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			tun.core.log.Errorf("SIOCSIFMTU fallback failed: %v.", err)
+			tun.core.log.Traceln(string(output))
+		}
+	}
+
+	// Create the address request
+	// FIXME: I don't work!
+	var ar in6_ifreq_addr
+	copy(ar.ifr_name[:], tun.iface.Name())
+	ar.ifru_addr.sin6_len = uint8(unsafe.Sizeof(ar.ifru_addr))
+	ar.ifru_addr.sin6_family = unix.AF_INET6
+	parts := strings.Split(strings.Split(addr, "/")[0], ":")
+	for i := 0; i < 8; i++ {
+		addr, _ := strconv.ParseUint(parts[i], 16, 16)
+		b := make([]byte, 16)
+		binary.LittleEndian.PutUint16(b, uint16(addr))
+		ar.ifru_addr.sin6_addr[i] = uint16(binary.BigEndian.Uint16(b))
+	}
+
+	// Set the interface address
+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(sfd), uintptr(SIOCSIFADDR_IN6), uintptr(unsafe.Pointer(&ar))); errno != 0 {
+		err = errno
+		tun.core.log.Errorf("Error in SIOCSIFADDR_IN6: %v", errno)
+
+		// Fall back to ifconfig to set the address
+		cmd := exec.Command("ifconfig", tun.iface.Name(), "inet6", addr)
+		tun.core.log.Warnf("Using ifconfig as fallback: %v", strings.Join(cmd.Args, " "))
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			tun.core.log.Errorf("SIOCSIFADDR_IN6 fallback failed: %v.", err)
+			tun.core.log.Traceln(string(output))
+		}
+	}
+
+	return nil
+}