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- // Copyright 2018 The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- package net
- import (
- "internal/poll"
- "internal/syscall/unix"
- "syscall"
- "unsafe"
- )
- type rawSockaddrDatalink struct {
- Len uint8
- Family uint8
- Index uint16
- Type uint8
- Nlen uint8
- Alen uint8
- Slen uint8
- Data [120]byte
- }
- type ifreq struct {
- Name [16]uint8
- Ifru [16]byte
- }
- const _KINFO_RT_IFLIST = (0x1 << 8) | 3 | (1 << 30)
- const _RTAX_NETMASK = 2
- const _RTAX_IFA = 5
- const _RTAX_MAX = 8
- func getIfList() ([]byte, error) {
- needed, err := syscall.Getkerninfo(_KINFO_RT_IFLIST, 0, 0, 0)
- if err != nil {
- return nil, err
- }
- tab := make([]byte, needed)
- _, err = syscall.Getkerninfo(_KINFO_RT_IFLIST, uintptr(unsafe.Pointer(&tab[0])), uintptr(unsafe.Pointer(&needed)), 0)
- if err != nil {
- return nil, err
- }
- return tab[:needed], nil
- }
- // If the ifindex is zero, interfaceTable returns mappings of all
- // network interfaces. Otherwise it returns a mapping of a specific
- // interface.
- func interfaceTable(ifindex int) ([]Interface, error) {
- tab, err := getIfList()
- if err != nil {
- return nil, err
- }
- sock, err := sysSocket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
- if err != nil {
- return nil, err
- }
- defer poll.CloseFunc(sock)
- var ift []Interface
- for len(tab) > 0 {
- ifm := (*syscall.IfMsgHdr)(unsafe.Pointer(&tab[0]))
- if ifm.Msglen == 0 {
- break
- }
- if ifm.Type == syscall.RTM_IFINFO {
- if ifindex == 0 || ifindex == int(ifm.Index) {
- sdl := (*rawSockaddrDatalink)(unsafe.Pointer(&tab[unsafe.Sizeof(syscall.IfMsgHdr)]))
- ifi := &Interface{Index: int(ifm.Index), Flags: linkFlags(ifm.Flags)}
- ifi.Name = string(sdl.Data[:sdl.Nlen])
- ifi.HardwareAddr = sdl.Data[sdl.Nlen : sdl.Nlen+sdl.Alen]
- // Retrieve MTU
- ifr := &ifreq{}
- copy(ifr.Name[:], ifi.Name)
- err = unix.Ioctl(sock, syscall.SIOCGIFMTU, unsafe.Pointer(ifr))
- if err != nil {
- return nil, err
- }
- ifi.MTU = int(ifr.Ifru[0])<<24 | int(ifr.Ifru[1])<<16 | int(ifr.Ifru[2])<<8 | int(ifr.Ifru[3])
- ift = append(ift, *ifi)
- if ifindex == int(ifm.Index) {
- break
- }
- }
- }
- tab = tab[ifm.Msglen:]
- }
- return ift, nil
- }
- func linkFlags(rawFlags int32) Flags {
- var f Flags
- if rawFlags&syscall.IFF_UP != 0 {
- f |= FlagUp
- }
- if rawFlags&syscall.IFF_BROADCAST != 0 {
- f |= FlagBroadcast
- }
- if rawFlags&syscall.IFF_LOOPBACK != 0 {
- f |= FlagLoopback
- }
- if rawFlags&syscall.IFF_POINTOPOINT != 0 {
- f |= FlagPointToPoint
- }
- if rawFlags&syscall.IFF_MULTICAST != 0 {
- f |= FlagMulticast
- }
- return f
- }
- // If the ifi is nil, interfaceAddrTable returns addresses for all
- // network interfaces. Otherwise it returns addresses for a specific
- // interface.
- func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
- tab, err := getIfList()
- if err != nil {
- return nil, err
- }
- var ifat []Addr
- for len(tab) > 0 {
- ifm := (*syscall.IfMsgHdr)(unsafe.Pointer(&tab[0]))
- if ifm.Msglen == 0 {
- break
- }
- if ifm.Type == syscall.RTM_NEWADDR {
- if ifi == nil || ifi.Index == int(ifm.Index) {
- mask := ifm.Addrs
- off := uint(unsafe.Sizeof(syscall.IfMsgHdr))
- var iprsa, nmrsa *syscall.RawSockaddr
- for i := uint(0); i < _RTAX_MAX; i++ {
- if mask&(1<<i) == 0 {
- continue
- }
- rsa := (*syscall.RawSockaddr)(unsafe.Pointer(&tab[off]))
- if i == _RTAX_NETMASK {
- nmrsa = rsa
- }
- if i == _RTAX_IFA {
- iprsa = rsa
- }
- off += (uint(rsa.Len) + 3) &^ 3
- }
- if iprsa != nil && nmrsa != nil {
- var mask IPMask
- var ip IP
- switch iprsa.Family {
- case syscall.AF_INET:
- ipsa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(iprsa))
- nmsa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(nmrsa))
- ip = IPv4(ipsa.Addr[0], ipsa.Addr[1], ipsa.Addr[2], ipsa.Addr[3])
- mask = IPv4Mask(nmsa.Addr[0], nmsa.Addr[1], nmsa.Addr[2], nmsa.Addr[3])
- case syscall.AF_INET6:
- ipsa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(iprsa))
- nmsa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(nmrsa))
- ip = make(IP, IPv6len)
- copy(ip, ipsa.Addr[:])
- mask = make(IPMask, IPv6len)
- copy(mask, nmsa.Addr[:])
- }
- ifa := &IPNet{IP: ip, Mask: mask}
- ifat = append(ifat, ifa)
- }
- }
- }
- tab = tab[ifm.Msglen:]
- }
- return ifat, nil
- }
- // interfaceMulticastAddrTable returns addresses for a specific
- // interface.
- func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
- return nil, nil
- }
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