270 lines
6.9 KiB
Go
270 lines
6.9 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"os"
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"syscall"
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"unsafe"
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)
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// If the ifindex is zero, interfaceTable returns mappings of all
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// network interfaces. Otherwise it returns a mapping of a specific
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// interface.
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func interfaceTable(ifindex int) ([]Interface, error) {
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tab, err := syscall.NetlinkRIB(syscall.RTM_GETLINK, syscall.AF_UNSPEC)
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if err != nil {
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return nil, os.NewSyscallError("netlinkrib", err)
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}
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msgs, err := syscall.ParseNetlinkMessage(tab)
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if err != nil {
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return nil, os.NewSyscallError("parsenetlinkmessage", err)
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}
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var ift []Interface
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loop:
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for _, m := range msgs {
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switch m.Header.Type {
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case syscall.NLMSG_DONE:
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break loop
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case syscall.RTM_NEWLINK:
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ifim := (*syscall.IfInfomsg)(unsafe.Pointer(&m.Data[0]))
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if ifindex == 0 || ifindex == int(ifim.Index) {
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attrs, err := syscall.ParseNetlinkRouteAttr(&m)
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if err != nil {
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return nil, os.NewSyscallError("parsenetlinkrouteattr", err)
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}
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ift = append(ift, *newLink(ifim, attrs))
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if ifindex == int(ifim.Index) {
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break loop
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}
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}
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}
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}
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return ift, nil
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}
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const (
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// See linux/if_arp.h.
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// Note that Linux doesn't support IPv4 over IPv6 tunneling.
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sysARPHardwareIPv4IPv4 = 768 // IPv4 over IPv4 tunneling
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sysARPHardwareIPv6IPv6 = 769 // IPv6 over IPv6 tunneling
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sysARPHardwareIPv6IPv4 = 776 // IPv6 over IPv4 tunneling
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sysARPHardwareGREIPv4 = 778 // any over GRE over IPv4 tunneling
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sysARPHardwareGREIPv6 = 823 // any over GRE over IPv6 tunneling
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)
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func newLink(ifim *syscall.IfInfomsg, attrs []syscall.NetlinkRouteAttr) *Interface {
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ifi := &Interface{Index: int(ifim.Index), Flags: linkFlags(ifim.Flags)}
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for _, a := range attrs {
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switch a.Attr.Type {
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case syscall.IFLA_ADDRESS:
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// We never return any /32 or /128 IP address
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// prefix on any IP tunnel interface as the
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// hardware address.
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switch len(a.Value) {
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case IPv4len:
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switch ifim.Type {
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case sysARPHardwareIPv4IPv4, sysARPHardwareGREIPv4, sysARPHardwareIPv6IPv4:
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continue
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}
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case IPv6len:
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switch ifim.Type {
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case sysARPHardwareIPv6IPv6, sysARPHardwareGREIPv6:
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continue
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}
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}
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var nonzero bool
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for _, b := range a.Value {
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if b != 0 {
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nonzero = true
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break
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}
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}
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if nonzero {
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ifi.HardwareAddr = a.Value[:]
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}
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case syscall.IFLA_IFNAME:
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ifi.Name = string(a.Value[:len(a.Value)-1])
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case syscall.IFLA_MTU:
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ifi.MTU = int(*(*uint32)(unsafe.Pointer(&a.Value[:4][0])))
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}
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}
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return ifi
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}
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func linkFlags(rawFlags uint32) Flags {
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var f Flags
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if rawFlags&syscall.IFF_UP != 0 {
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f |= FlagUp
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}
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if rawFlags&syscall.IFF_BROADCAST != 0 {
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f |= FlagBroadcast
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}
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if rawFlags&syscall.IFF_LOOPBACK != 0 {
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f |= FlagLoopback
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}
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if rawFlags&syscall.IFF_POINTOPOINT != 0 {
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f |= FlagPointToPoint
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}
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if rawFlags&syscall.IFF_MULTICAST != 0 {
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f |= FlagMulticast
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}
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return f
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}
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// If the ifi is nil, interfaceAddrTable returns addresses for all
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// network interfaces. Otherwise it returns addresses for a specific
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// interface.
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func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
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tab, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
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if err != nil {
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return nil, os.NewSyscallError("netlinkrib", err)
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}
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msgs, err := syscall.ParseNetlinkMessage(tab)
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if err != nil {
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return nil, os.NewSyscallError("parsenetlinkmessage", err)
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}
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var ift []Interface
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if ifi == nil {
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var err error
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ift, err = interfaceTable(0)
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if err != nil {
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return nil, err
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}
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}
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ifat, err := addrTable(ift, ifi, msgs)
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if err != nil {
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return nil, err
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}
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return ifat, nil
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}
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func addrTable(ift []Interface, ifi *Interface, msgs []syscall.NetlinkMessage) ([]Addr, error) {
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var ifat []Addr
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loop:
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for _, m := range msgs {
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switch m.Header.Type {
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case syscall.NLMSG_DONE:
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break loop
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case syscall.RTM_NEWADDR:
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ifam := (*syscall.IfAddrmsg)(unsafe.Pointer(&m.Data[0]))
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if len(ift) != 0 || ifi.Index == int(ifam.Index) {
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if len(ift) != 0 {
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var err error
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ifi, err = interfaceByIndex(ift, int(ifam.Index))
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if err != nil {
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return nil, err
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}
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}
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attrs, err := syscall.ParseNetlinkRouteAttr(&m)
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if err != nil {
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return nil, os.NewSyscallError("parsenetlinkrouteattr", err)
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}
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ifa := newAddr(ifam, attrs)
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if ifa != nil {
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ifat = append(ifat, ifa)
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}
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}
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}
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}
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return ifat, nil
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}
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func newAddr(ifam *syscall.IfAddrmsg, attrs []syscall.NetlinkRouteAttr) Addr {
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var ipPointToPoint bool
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// Seems like we need to make sure whether the IP interface
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// stack consists of IP point-to-point numbered or unnumbered
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// addressing.
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for _, a := range attrs {
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if a.Attr.Type == syscall.IFA_LOCAL {
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ipPointToPoint = true
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break
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}
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}
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for _, a := range attrs {
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if ipPointToPoint && a.Attr.Type == syscall.IFA_ADDRESS {
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continue
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}
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switch ifam.Family {
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case syscall.AF_INET:
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return &IPNet{IP: IPv4(a.Value[0], a.Value[1], a.Value[2], a.Value[3]), Mask: CIDRMask(int(ifam.Prefixlen), 8*IPv4len)}
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case syscall.AF_INET6:
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ifa := &IPNet{IP: make(IP, IPv6len), Mask: CIDRMask(int(ifam.Prefixlen), 8*IPv6len)}
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copy(ifa.IP, a.Value[:])
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return ifa
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}
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}
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return nil
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}
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// interfaceMulticastAddrTable returns addresses for a specific
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// interface.
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func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
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ifmat4 := parseProcNetIGMP("/proc/net/igmp", ifi)
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ifmat6 := parseProcNetIGMP6("/proc/net/igmp6", ifi)
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return append(ifmat4, ifmat6...), nil
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}
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func parseProcNetIGMP(path string, ifi *Interface) []Addr {
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fd, err := open(path)
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if err != nil {
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return nil
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}
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defer fd.close()
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var (
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ifmat []Addr
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name string
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)
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fd.readLine() // skip first line
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b := make([]byte, IPv4len)
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for l, ok := fd.readLine(); ok; l, ok = fd.readLine() {
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f := splitAtBytes(l, " :\r\t\n")
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if len(f) < 4 {
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continue
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}
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switch {
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case l[0] != ' ' && l[0] != '\t': // new interface line
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name = f[1]
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case len(f[0]) == 8:
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if ifi == nil || name == ifi.Name {
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// The Linux kernel puts the IP
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// address in /proc/net/igmp in native
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// endianness.
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for i := 0; i+1 < len(f[0]); i += 2 {
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b[i/2], _ = xtoi2(f[0][i:i+2], 0)
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}
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i := *(*uint32)(unsafe.Pointer(&b[:4][0]))
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ifma := &IPAddr{IP: IPv4(byte(i>>24), byte(i>>16), byte(i>>8), byte(i))}
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ifmat = append(ifmat, ifma)
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}
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}
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}
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return ifmat
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}
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func parseProcNetIGMP6(path string, ifi *Interface) []Addr {
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fd, err := open(path)
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if err != nil {
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return nil
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}
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defer fd.close()
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var ifmat []Addr
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b := make([]byte, IPv6len)
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for l, ok := fd.readLine(); ok; l, ok = fd.readLine() {
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f := splitAtBytes(l, " \r\t\n")
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if len(f) < 6 {
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continue
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}
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if ifi == nil || f[1] == ifi.Name {
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for i := 0; i+1 < len(f[2]); i += 2 {
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b[i/2], _ = xtoi2(f[2][i:i+2], 0)
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}
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ifma := &IPAddr{IP: IP{b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7], b[8], b[9], b[10], b[11], b[12], b[13], b[14], b[15]}}
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ifmat = append(ifmat, ifma)
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}
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}
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return ifmat
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}
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