Golang DeserializeIfAddrmsg Examples

Example #1

File: addr_linux.go Project: currantlabs/netlink

// 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
}

Example #2

File: addr_linux.go Project: currantlabs/netlink

// 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
}