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// Copyright 2011 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.
// Network interface identification for Linux
package net
import (
"os"
"syscall"
"unsafe"
)
// If the ifindex is zero, interfaceTable returns mappings of all
// network interfaces. Otheriwse it returns a mapping of a specific
// interface.
func interfaceTable(ifindex int) ([]Interface, os.Error) {
var (
ift []Interface
tab []byte
msgs []syscall.NetlinkMessage
e int
)
tab, e = syscall.NetlinkRIB(syscall.RTM_GETLINK, syscall.AF_UNSPEC)
if e != 0 {
return nil, os.NewSyscallError("netlink rib", e)
}
msgs, e = syscall.ParseNetlinkMessage(tab)
if e != 0 {
return nil, os.NewSyscallError("netlink message", e)
}
for _, m := range msgs {
switch m.Header.Type {
case syscall.NLMSG_DONE:
goto done
case syscall.RTM_NEWLINK:
ifim := (*syscall.IfInfomsg)(unsafe.Pointer(&m.Data[0]))
if ifindex == 0 || ifindex == int(ifim.Index) {
attrs, e := syscall.ParseNetlinkRouteAttr(&m)
if e != 0 {
return nil, os.NewSyscallError("netlink routeattr", e)
}
ifi := newLink(attrs, ifim)
ift = append(ift, ifi)
}
}
}
done:
return ift, nil
}
func newLink(attrs []syscall.NetlinkRouteAttr, ifim *syscall.IfInfomsg) Interface {
ifi := Interface{Index: int(ifim.Index), Flags: linkFlags(ifim.Flags)}
for _, a := range attrs {
switch a.Attr.Type {
case syscall.IFLA_ADDRESS:
var nonzero bool
for _, b := range a.Value {
if b != 0 {
nonzero = true
}
}
if nonzero {
ifi.HardwareAddr = a.Value[:]
}
case syscall.IFLA_IFNAME:
ifi.Name = string(a.Value[:len(a.Value)-1])
case syscall.IFLA_MTU:
ifi.MTU = int(uint32(a.Value[3])<<24 | uint32(a.Value[2])<<16 | uint32(a.Value[1])<<8 | uint32(a.Value[0]))
}
}
return ifi
}
func linkFlags(rawFlags uint32) 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 ifindex is zero, interfaceAddrTable returns addresses
// for all network interfaces. Otherwise it returns addresses
// for a specific interface.
func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
var (
ifat4 []Addr
ifat6 []Addr
tab []byte
msgs4 []syscall.NetlinkMessage
msgs6 []syscall.NetlinkMessage
e int
err os.Error
)
tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET)
if e != 0 {
return nil, os.NewSyscallError("netlink rib", e)
}
msgs4, e = syscall.ParseNetlinkMessage(tab)
if e != 0 {
return nil, os.NewSyscallError("netlink message", e)
}
ifat4, err = addrTable(msgs4, ifindex)
if err != nil {
return nil, err
}
tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET6)
if e != 0 {
return nil, os.NewSyscallError("netlink rib", e)
}
msgs6, e = syscall.ParseNetlinkMessage(tab)
if e != 0 {
return nil, os.NewSyscallError("netlink message", e)
}
ifat6, err = addrTable(msgs6, ifindex)
if err != nil {
return nil, err
}
return append(ifat4, ifat6...), nil
}
func addrTable(msgs []syscall.NetlinkMessage, ifindex int) ([]Addr, os.Error) {
var ifat []Addr
for _, m := range msgs {
switch m.Header.Type {
case syscall.NLMSG_DONE:
goto done
case syscall.RTM_NEWADDR:
ifam := (*syscall.IfAddrmsg)(unsafe.Pointer(&m.Data[0]))
if ifindex == 0 || ifindex == int(ifam.Index) {
attrs, e := syscall.ParseNetlinkRouteAttr(&m)
if e != 0 {
return nil, os.NewSyscallError("netlink routeattr", e)
}
ifat = append(ifat, newAddr(attrs, int(ifam.Family))...)
}
}
}
done:
return ifat, nil
}
func newAddr(attrs []syscall.NetlinkRouteAttr, family int) []Addr {
var ifat []Addr
for _, a := range attrs {
switch a.Attr.Type {
case syscall.IFA_ADDRESS:
ifa := IPAddr{}
switch family {
case syscall.AF_INET:
ifa.IP = IPv4(a.Value[0], a.Value[1], a.Value[2], a.Value[3])
case syscall.AF_INET6:
ifa.IP = make(IP, IPv6len)
copy(ifa.IP, a.Value[:])
}
ifat = append(ifat, ifa.toAddr())
}
}
return ifat
}
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