123 lines
2.9 KiB
Go
123 lines
2.9 KiB
Go
//go:build linux
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package iface
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import (
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"net"
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"syscall"
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"unsafe"
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"golang.org/x/sys/unix"
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)
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// as per https://github.com/torvalds/linux/blob/7ddb58cb0ecae8e8b6181d736a87667cc9ab8389/include/uapi/linux/route.h#L31-L48
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type rtentry struct {
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pad1 uint
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dst syscall.RawSockaddrInet4
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gateway syscall.RawSockaddrInet4
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genmask syscall.RawSockaddrInet4
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flags uint16
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pad [512]byte
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}
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type Configsocket struct {
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fd int
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iface string
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}
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func NewConfigSocket(iface string) (Configsocket, error) {
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fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
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if err != nil {
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return Configsocket{}, err
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}
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return Configsocket{
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fd: fd,
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iface: iface,
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}, nil
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}
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func (cs Configsocket) Close() error {
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return syscall.Close(cs.fd)
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}
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func (cs Configsocket) ifreqAddr(request uint, addr net.IP) error {
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ifr, err := unix.NewIfreq(cs.iface)
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if err != nil {
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return err
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}
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// Ensure we use the 4-byte net.IP representation.
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if err := ifr.SetInet4Addr(addr.To4()); err != nil {
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return err
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}
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if err := unix.IoctlIfreq(cs.fd, request, ifr); err != nil {
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return err
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}
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return nil
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}
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func (cs Configsocket) SetAddress(addr net.IP) error {
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return cs.ifreqAddr(syscall.SIOCSIFADDR, addr)
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}
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func (cs Configsocket) SetNetmask(addr net.IPMask) error {
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return cs.ifreqAddr(syscall.SIOCSIFNETMASK, net.IP(addr))
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}
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func (cs Configsocket) SetBroadcast(addr net.IP) error {
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return cs.ifreqAddr(syscall.SIOCSIFBRDADDR, addr)
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}
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func (cs Configsocket) Up() error {
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ifr, err := unix.NewIfreq(cs.iface)
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if err != nil {
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return err
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}
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if err := unix.IoctlIfreq(cs.fd, unix.SIOCGIFFLAGS, ifr); err != nil {
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return err
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}
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flags := ifr.Uint16()
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flags |= syscall.IFF_UP
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flags |= syscall.IFF_RUNNING
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ifr.SetUint16(flags)
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if err := unix.IoctlIfreq(cs.fd, unix.SIOCSIFFLAGS, ifr); err != nil {
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return err
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}
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return nil
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}
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func (cs Configsocket) AddRoute(dst, gateway net.IP, genmask net.IPMask) syscall.Errno {
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req := rtentry{
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dst: syscall.RawSockaddrInet4{Family: syscall.AF_INET},
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gateway: syscall.RawSockaddrInet4{Family: syscall.AF_INET},
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genmask: syscall.RawSockaddrInet4{Family: syscall.AF_INET},
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flags: syscall.RTF_UP | syscall.RTF_GATEWAY,
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}
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copy(req.dst.Addr[:], dst)
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copy(req.gateway.Addr[:], gateway)
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copy(req.genmask.Addr[:], genmask)
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_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(cs.fd), syscall.SIOCADDRT, uintptr(unsafe.Pointer(&req)))
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return errno
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}
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func (cs Configsocket) DelRoute(dst, gateway net.IP, genmask net.IPMask) syscall.Errno {
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req := rtentry{
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dst: syscall.RawSockaddrInet4{Family: syscall.AF_INET},
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gateway: syscall.RawSockaddrInet4{Family: syscall.AF_INET},
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genmask: syscall.RawSockaddrInet4{Family: syscall.AF_INET},
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flags: syscall.RTF_UP | syscall.RTF_GATEWAY,
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}
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copy(req.dst.Addr[:], dst)
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copy(req.gateway.Addr[:], gateway)
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copy(req.genmask.Addr[:], genmask)
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_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(cs.fd), syscall.SIOCDELRT, uintptr(unsafe.Pointer(&req)))
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return errno
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}
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