package netlink
import (
"fmt"
"net"
"strings"
"syscall"
"github.com/vishvananda/netlink/nl"
"github.com/vishvananda/netns"
"golang.org/x/sys/unix"
)
// AddrAdd will add an IP address to a link device.
//
// Equivalent to: `ip addr add $addr dev $link`
//
// If `addr` is an IPv4 address and the broadcast address is not given, it
// will be automatically computed based on the IP mask if /30 or larger.
func AddrAdd(link Link, addr *Addr) error {
return pkgHandle.AddrAdd(link, addr)
}
// AddrAdd will add an IP address to a link device.
//
// Equivalent to: `ip addr add $addr dev $link`
//
// If `addr` is an IPv4 address and the broadcast address is not given, it
// will be automatically computed based on the IP mask if /30 or larger.
func (h *Handle) AddrAdd(link Link, addr *Addr) error {
req := h.newNetlinkRequest(unix.RTM_NEWADDR, unix.NLM_F_CREATE|unix.NLM_F_EXCL|unix.NLM_F_ACK)
return h.addrHandle(link, addr, req)
}
// AddrReplace will replace (or, if not present, add) an IP address on a link device.
//
// Equivalent to: `ip addr replace $addr dev $link`
//
// If `addr` is an IPv4 address and the broadcast address is not given, it
// will be automatically computed based on the IP mask if /30 or larger.
func AddrReplace(link Link, addr *Addr) error {
return pkgHandle.AddrReplace(link, addr)
}
// AddrReplace will replace (or, if not present, add) an IP address on a link device.
//
// Equivalent to: `ip addr replace $addr dev $link`
//
// If `addr` is an IPv4 address and the broadcast address is not given, it
// will be automatically computed based on the IP mask if /30 or larger.
func (h *Handle) AddrReplace(link Link, addr *Addr) error {
req := h.newNetlinkRequest(unix.RTM_NEWADDR, unix.NLM_F_CREATE|unix.NLM_F_REPLACE|unix.NLM_F_ACK)
return h.addrHandle(link, addr, req)
}
// AddrDel will delete an IP address from a link device.
//
// Equivalent to: `ip addr del $addr dev $link`
//
// If `addr` is an IPv4 address and the broadcast address is not given, it
// will be automatically computed based on the IP mask if /30 or larger.
func AddrDel(link Link, addr *Addr) error {
return pkgHandle.AddrDel(link, addr)
}
// AddrDel will delete an IP address from a link device.
// Equivalent to: `ip addr del $addr dev $link`
//
// If `addr` is an IPv4 address and the broadcast address is not given, it
// will be automatically computed based on the IP mask if /30 or larger.
func (h *Handle) AddrDel(link Link, addr *Addr) error {
req := h.newNetlinkRequest(unix.RTM_DELADDR, unix.NLM_F_ACK)
return h.addrHandle(link, addr, req)
}
func (h *Handle) addrHandle(link Link, addr *Addr, req *nl.NetlinkRequest) error {
family := nl.GetIPFamily(addr.IP)
msg := nl.NewIfAddrmsg(family)
msg.Scope = uint8(addr.Scope)
if link == nil {
msg.Index = uint32(addr.LinkIndex)
} else {
base := link.Attrs()
if addr.Label != "" && !strings.HasPrefix(addr.Label, base.Name) {
return fmt.Errorf("label must begin with interface name")
}
h.ensureIndex(base)
msg.Index = uint32(base.Index)
}
mask := addr.Mask
if addr.Peer != nil {
mask = addr.Peer.Mask
}
prefixlen, masklen := mask.Size()
msg.Prefixlen = uint8(prefixlen)
req.AddData(msg)
var localAddrData []byte
if family == FAMILY_V4 {
localAddrData = addr.IP.To4()
} else {
localAddrData = addr.IP.To16()
}
localData := nl.NewRtAttr(unix.IFA_LOCAL, localAddrData)
req.AddData(localData)
var peerAddrData []byte
if addr.Peer != nil {
if family == FAMILY_V4 {
peerAddrData = addr.Peer.IP.To4()
} else {
peerAddrData = addr.Peer.IP.To16()
}
} else {
peerAddrData = localAddrData
}
addressData := nl.NewRtAttr(unix.IFA_ADDRESS, peerAddrData)
req.AddData(addressData)
if addr.Flags != 0 {
if addr.Flags <= 0xff {
msg.IfAddrmsg.Flags = uint8(addr.Flags)
} else {
b := make([]byte, 4)
native.PutUint32(b, uint32(addr.Flags))
flagsData := nl.NewRtAttr(unix.IFA_FLAGS, b)
req.AddData(flagsData)
}
}
if family == FAMILY_V4 {
// Automatically set the broadcast address if it is unset and the
// subnet is large enough to sensibly have one (/30 or larger).
// See: RFC 3021
if addr.Broadcast == nil && prefixlen < 31 {
calcBroadcast := make(net.IP, masklen/8)
for i := range localAddrData {
calcBroadcast[i] = localAddrData[i] | ^mask[i]
}
addr.Broadcast = calcBroadcast
}
if addr.Broadcast != nil {
req.AddData(nl.NewRtAttr(unix.IFA_BROADCAST, addr.Broadcast))
}
if addr.Label != "" {
labelData := nl.NewRtAttr(unix.IFA_LABEL, nl.ZeroTerminated(addr.Label))
req.AddData(labelData)
}
}
// 0 is the default value for these attributes. However, 0 means "expired", while the least-surprising default
// value should be "forever". To compensate for that, only add the attributes if at least one of the values is
// non-zero, which means the caller has explicitly set them
if addr.ValidLft > 0 || addr.PreferedLft > 0 {
cachedata := nl.IfaCacheInfo{unix.IfaCacheinfo{
Valid: uint32(addr.ValidLft),
Prefered: uint32(addr.PreferedLft),
}}
req.AddData(nl.NewRtAttr(unix.IFA_CACHEINFO, cachedata.Serialize()))
}
_, err := req.Execute(unix.NETLINK_ROUTE, 0)
return err
}
// AddrList gets a list of IP addresses in the system.
// Equivalent to: `ip addr show`.
// The list can be filtered by link and ip family.
func AddrList(link Link, family int) ([]Addr, error) {
return pkgHandle.AddrList(link, family)
}
// AddrList gets a list of IP addresses in the system.
// Equivalent to: `ip addr show`.
// The list can be filtered by link and ip family.
func (h *Handle) AddrList(link Link, family int) ([]Addr, error) {
req := h.newNetlinkRequest(unix.RTM_GETADDR, unix.NLM_F_DUMP)
msg := nl.NewIfAddrmsg(family)
req.AddData(msg)
msgs, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWADDR)
if err != nil {
return nil, err
}
indexFilter := 0
if link != nil {
base := link.Attrs()
h.ensureIndex(base)
indexFilter = base.Index
}
var res []Addr
for _, m := range msgs {
addr, msgFamily, err := parseAddr(m)
if err != nil {
return res, err
}
if link != nil && addr.LinkIndex != indexFilter {
// Ignore messages from other interfaces
continue
}
if family != FAMILY_ALL && msgFamily != family {
continue
}
res = append(res, addr)
}
return res, nil
}
func parseAddr(m []byte) (addr Addr, family int, err error) {
msg := nl.DeserializeIfAddrmsg(m)
family = -1
addr.LinkIndex = -1
attrs, err1 := nl.ParseRouteAttr(m[msg.Len():])
if err1 != nil {
err = err1
return
}
family = int(msg.Family)
addr.LinkIndex = int(msg.Index)
var local, dst *net.IPNet
for _, attr := range attrs {
switch attr.Attr.Type {
case unix.IFA_ADDRESS:
dst = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)),
}
case unix.IFA_LOCAL:
// iproute2 manual:
// If a peer address is specified, the local address
// cannot have a prefix length. The network prefix is
// associated with the peer rather than with the local
// address.
n := 8 * len(attr.Value)
local = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(n, n),
}
case unix.IFA_BROADCAST:
addr.Broadcast = attr.Value
case unix.IFA_LABEL:
addr.Label = string(attr.Value[:len(attr.Value)-1])
case unix.IFA_FLAGS:
addr.Flags = int(native.Uint32(attr.Value[0:4]))
case unix.IFA_CACHEINFO:
ci := nl.DeserializeIfaCacheInfo(attr.Value)
addr.PreferedLft = int(ci.Prefered)
addr.ValidLft = int(ci.Valid)
}
}
// libnl addr.c comment:
// IPv6 sends the local address as IFA_ADDRESS with no
// IFA_LOCAL, IPv4 sends both IFA_LOCAL and IFA_ADDRESS
// with IFA_ADDRESS being the peer address if they differ
//
// But obviously, as there are IPv6 PtP addresses, too,
// IFA_LOCAL should also be handled for IPv6.
if local != nil {
if family == FAMILY_V4 && dst != nil && local.IP.Equal(dst.IP) {
addr.IPNet = dst
} else {
addr.IPNet = local
addr.Peer = dst
}
} else {
addr.IPNet = dst
}
addr.Scope = int(msg.Scope)
return
}
type AddrUpdate struct {
LinkAddress net.IPNet
LinkIndex int
Flags int
Scope int
PreferedLft int
ValidLft int
NewAddr bool // true=added false=deleted
}
// AddrSubscribe takes a chan down which notifications will be sent
// when addresses change. Close the 'done' chan to stop subscription.
func AddrSubscribe(ch chan<- AddrUpdate, done <-chan struct{}) error {
return addrSubscribeAt(netns.None(), netns.None(), ch, done, nil, false, 0, nil, false)
}
// AddrSubscribeAt works like AddrSubscribe plus it allows the caller
// to choose the network namespace in which to subscribe (ns).
func AddrSubscribeAt(ns netns.NsHandle, ch chan<- AddrUpdate, done <-chan struct{}) error {
return addrSubscribeAt(ns, netns.None(), ch, done, nil, false, 0, nil, false)
}
// AddrSubscribeOptions contains a set of options to use with
// AddrSubscribeWithOptions.
type AddrSubscribeOptions struct {
Namespace *netns.NsHandle
ErrorCallback func(error)
ListExisting bool
ReceiveBufferSize int
ReceiveBufferForceSize bool
ReceiveTimeout *unix.Timeval
}
// AddrSubscribeWithOptions work like AddrSubscribe but enable to
// provide additional options to modify the behavior. Currently, the
// namespace can be provided as well as an error callback.
func AddrSubscribeWithOptions(ch chan<- AddrUpdate, done <-chan struct{}, options AddrSubscribeOptions) error {
if options.Namespace == nil {
none := netns.None()
options.Namespace = &none
}
return addrSubscribeAt(*options.Namespace, netns.None(), ch, done, options.ErrorCallback, options.ListExisting,
options.ReceiveBufferSize, options.ReceiveTimeout, options.ReceiveBufferForceSize)
}
func addrSubscribeAt(newNs, curNs netns.NsHandle, ch chan<- AddrUpdate, done <-chan struct{}, cberr func(error), listExisting bool,
rcvbuf int, rcvTimeout *unix.Timeval, rcvBufForce bool) error {
s, err := nl.SubscribeAt(newNs, curNs, unix.NETLINK_ROUTE, unix.RTNLGRP_IPV4_IFADDR, unix.RTNLGRP_IPV6_IFADDR)
if err != nil {
return err
}
if rcvTimeout != nil {
if err := s.SetReceiveTimeout(rcvTimeout); err != nil {
return err
}
}
if rcvbuf != 0 {
err = s.SetReceiveBufferSize(rcvbuf, rcvBufForce)
if err != nil {
return err
}
}
if done != nil {
go func() {
<-done
s.Close()
}()
}
if listExisting {
req := pkgHandle.newNetlinkRequest(unix.RTM_GETADDR,
unix.NLM_F_DUMP)
infmsg := nl.NewIfInfomsg(unix.AF_UNSPEC)
req.AddData(infmsg)
if err := s.Send(req); err != nil {
return err
}
}
go func() {
defer close(ch)
for {
msgs, from, err := s.Receive()
if err != nil {
if cberr != nil {
cberr(fmt.Errorf("Receive failed: %v",
err))
}
return
}
if from.Pid != nl.PidKernel {
if cberr != nil {
cberr(fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel))
}
continue
}
for _, m := range msgs {
if m.Header.Type == unix.NLMSG_DONE {
continue
}
if m.Header.Type == unix.NLMSG_ERROR {
error := int32(native.Uint32(m.Data[0:4]))
if error == 0 {
continue
}
if cberr != nil {
cberr(fmt.Errorf("error message: %v",
syscall.Errno(-error)))
}
continue
}
msgType := m.Header.Type
if msgType != unix.RTM_NEWADDR && msgType != unix.RTM_DELADDR {
if cberr != nil {
cberr(fmt.Errorf("bad message type: %d", msgType))
}
continue
}
addr, _, err := parseAddr(m.Data)
if err != nil {
if cberr != nil {
cberr(fmt.Errorf("could not parse address: %v", err))
}
continue
}
ch <- AddrUpdate{LinkAddress: *addr.IPNet,
LinkIndex: addr.LinkIndex,
NewAddr: msgType == unix.RTM_NEWADDR,
Flags: addr.Flags,
Scope: addr.Scope,
PreferedLft: addr.PreferedLft,
ValidLft: addr.ValidLft}
}
}
}()
return nil
}
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