forked from vishvananda/netlink
/
addr_linux.go
221 lines (188 loc) · 5.3 KB
/
addr_linux.go
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package netlink
import (
"fmt"
"log"
"net"
"strings"
"syscall"
"github.com/currantlabs/netlink/nl"
)
// IFA_FLAGS is a u32 attribute.
const IFA_FLAGS = 0x8
// AddrAdd will add an IP address to a link device.
// Equivalent to: `ip addr add $addr dev $link`
func AddrAdd(link Link, addr *Addr) error {
req := nl.NewNetlinkRequest(syscall.RTM_NEWADDR, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
return addrHandle(link, addr, req)
}
// AddrDel will delete an IP address from a link device.
// Equivalent to: `ip addr del $addr dev $link`
func AddrDel(link Link, addr *Addr) error {
req := nl.NewNetlinkRequest(syscall.RTM_DELADDR, syscall.NLM_F_ACK)
return addrHandle(link, addr, req)
}
func addrHandle(link Link, addr *Addr, req *nl.NetlinkRequest) error {
base := link.Attrs()
if addr.Label != "" && !strings.HasPrefix(addr.Label, base.Name) {
return fmt.Errorf("label must begin with interface name")
}
ensureIndex(base)
family := nl.GetIPFamily(addr.IP)
msg := nl.NewIfAddrmsg(family)
msg.Index = uint32(base.Index)
msg.Scope = uint8(addr.Scope)
prefixlen, _ := addr.Mask.Size()
msg.Prefixlen = uint8(prefixlen)
req.AddData(msg)
var addrData []byte
if family == FAMILY_V4 {
addrData = addr.IP.To4()
} else {
addrData = addr.IP.To16()
}
localData := nl.NewRtAttr(syscall.IFA_LOCAL, addrData)
req.AddData(localData)
addressData := nl.NewRtAttr(syscall.IFA_ADDRESS, addrData)
req.AddData(addressData)
if addr.Flags != 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(addr.Flags))
flagsData := nl.NewRtAttr(IFA_FLAGS, b)
req.AddData(flagsData)
}
if addr.Label != "" {
labelData := nl.NewRtAttr(syscall.IFA_LABEL, nl.ZeroTerminated(addr.Label))
req.AddData(labelData)
}
_, err := req.Execute(syscall.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) {
req := nl.NewNetlinkRequest(syscall.RTM_GETADDR, syscall.NLM_F_DUMP)
msg := nl.NewIfInfomsg(family)
req.AddData(msg)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWADDR)
if err != nil {
return nil, err
}
index := 0
if link != nil {
base := link.Attrs()
ensureIndex(base)
index = base.Index
}
var res []Addr
for _, m := range msgs {
msg := nl.DeserializeIfAddrmsg(m)
if link != nil && msg.Index != uint32(index) {
// Ignore messages from other interfaces
continue
}
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
var local, dst *net.IPNet
var addr Addr
for _, attr := range attrs {
switch attr.Attr.Type {
case syscall.IFA_ADDRESS:
dst = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)),
}
case syscall.IFA_LOCAL:
local = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)),
}
case syscall.IFA_LABEL:
addr.Label = string(attr.Value[:len(attr.Value)-1])
case IFA_FLAGS:
addr.Flags = int(native.Uint32(attr.Value[0:4]))
}
}
// IFA_LOCAL should be there but if not, fall back to IFA_ADDRESS
if local != nil {
addr.IPNet = local
} else {
addr.IPNet = dst
}
addr.Scope = int(msg.Scope)
res = append(res, addr)
}
return res, nil
}
type AddrUpdate struct {
LinkAddress net.IPNet
LinkIndex 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 {
s, err := nl.Subscribe(syscall.NETLINK_ROUTE, syscall.RTNLGRP_IPV4_IFADDR, syscall.RTNLGRP_IPV6_IFADDR)
if err != nil {
return err
}
if done != nil {
go func() {
<-done
s.Close()
}()
}
go func() {
defer close(ch)
for {
msgs, err := s.Receive()
if err != nil {
log.Printf("netlink.AddrSubscribe: Receive() error: %v", err)
return
}
for _, m := range msgs {
msgType := m.Header.Type
if msgType != syscall.RTM_NEWADDR && msgType != syscall.RTM_DELADDR {
log.Printf("netlink.AddrSubscribe: bad message type: %d", msgType)
continue
}
msg := nl.DeserializeIfAddrmsg(m.Data)
attrs, err := nl.ParseRouteAttr(m.Data[msg.Len():])
if err != nil {
log.Printf("netlink.AddrSubscribe: nl.ParseRouteAttr() error: %v", err)
return
}
var local, dst *net.IPNet
var addr Addr
for _, attr := range attrs {
switch attr.Attr.Type {
case syscall.IFA_ADDRESS:
dst = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)),
}
case syscall.IFA_LOCAL:
local = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)),
}
case syscall.IFA_LABEL:
addr.Label = string(attr.Value[:len(attr.Value)-1])
case IFA_FLAGS:
addr.Flags = int(native.Uint32(attr.Value[0:4]))
}
}
// IFA_LOCAL should be there but if not, fall back to IFA_ADDRESS
if local != nil {
addr.IPNet = local
} else {
addr.IPNet = dst
}
ch <- AddrUpdate{LinkAddress: *addr.IPNet, LinkIndex: int(msg.Index), NewAddr: msgType == syscall.RTM_NEWADDR}
}
}
}()
return nil
}