util.go

/***
Copyright 2014 Cisco Systems Inc. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package ofnet

import (
	"errors"
	"fmt"
	"hash/fnv"
	"math/rand"
	"net"
	"strconv"
	"strings"

	"github.com/contiv/libOpenflow/openflow13"
	"github.com/contiv/libOpenflow/protocol"
	"github.com/contiv/ofnet/ofctrl"
	"github.com/vishvananda/netlink"

	log "github.com/Sirupsen/logrus"
)

// ParseCIDR parses a CIDR string into a gateway IP and length.
func ParseCIDR(cidrStr string) (string, uint, error) {
	strs := strings.Split(cidrStr, "/")
	if len(strs) != 2 {
		return "", 0, errors.New("invalid cidr format")
	}

	subnetStr := strs[0]
	subnetLen, err := strconv.Atoi(strs[1])
	if subnetLen > 32 || err != nil {
		return "", 0, errors.New("invalid mask in gateway/mask specification ")
	}

	return subnetStr, uint(subnetLen), nil
}

// ParseIPAddrMaskString Parse IP addr string
func ParseIPAddrMaskString(ipAddr string) (*net.IP, *net.IP, error) {
	if strings.Contains(ipAddr, "/") {
		ipDav, ipNet, err := net.ParseCIDR(ipAddr)
		if err != nil {
			log.Errorf("Error parsing ip %s. Err: %v", ipAddr, err)
			return nil, nil, err
		}

		ipMask := net.ParseIP("255.255.255.255").Mask(ipNet.Mask)

		return &ipDav, &ipMask, nil
	}

	ipDav := net.ParseIP(ipAddr)
	if ipDav == nil {
		log.Errorf("Error parsing ip %s.", ipAddr)
		return nil, nil, errors.New("Error parsing ip address")
	}

	ipMask := net.ParseIP("255.255.255.255")

	return &ipDav, &ipMask, nil

}

// BuildGarpPkt builds a Gratuitous ARP packet
func BuildGarpPkt(ip net.IP, mac net.HardwareAddr, vlanID uint16) *openflow13.PacketOut {

	zMac, _ := net.ParseMAC("00:00:00:00:00:00")
	bMac, _ := net.ParseMAC("FF:FF:FF:FF:FF:FF")

	garpPkt, _ := protocol.NewARP(protocol.Type_Request)
	garpPkt.HWSrc = mac
	garpPkt.IPSrc = ip
	garpPkt.HWDst = zMac
	garpPkt.IPDst = ip

	// Build the ethernet packet
	ethPkt := protocol.NewEthernet()
	ethPkt.VLANID.VID = vlanID
	ethPkt.HWDst = bMac
	ethPkt.HWSrc = mac
	ethPkt.Ethertype = 0x0806
	ethPkt.Data = garpPkt

	// Construct Packet out
	pktOut := openflow13.NewPacketOut()
	pktOut.Data = ethPkt

	return pktOut
}

func ipChecksum(data []byte) uint16 {
	csum := uint32(0)
	length := len(data) - 1
	for i := 0; i < length; i += 2 {
		csum += uint32(data[i]) << 8
		csum += uint32(data[i+1])
	}
	if len(data)%2 == 1 {
		csum += uint32(data[length]) << 8
	}
	for csum > 0xffff {
		csum = (csum >> 16) + (csum & 0xffff)
	}
	return ^uint16(csum)
}

func buildDnsForwardPkt(ethInPkt *protocol.Ethernet) *protocol.Ethernet {
	ipPkt := ethInPkt.Data.(*protocol.IPv4)
	ethPkt := protocol.NewEthernet()
	ethPkt.HWSrc = ethInPkt.HWSrc
	ethPkt.HWDst = ethInPkt.HWDst
	ethPkt.VLANID.VID = nameServerInternalVlanId
	ethPkt.Ethertype = ethInPkt.Ethertype
	ethPkt.Data = ipPkt
	return ethPkt
}

func buildUDPRespPkt(inEth *protocol.Ethernet, uData []byte) (*protocol.Ethernet, error) {
	inIp := inEth.Data.(*protocol.IPv4)
	inUdp := inIp.Data.(*protocol.UDP)

	outUdp := protocol.NewUDP()
	outUdp.PortDst = inUdp.PortSrc
	outUdp.PortSrc = inUdp.PortDst
	outUdp.Length = uint16(8 + len(uData))
	outUdp.Data = append(outUdp.Data, uData...)

	outIp := protocol.NewIPv4()
	outIp.Version = inIp.Version
	outIp.IHL = 5
	outIp.DSCP = inIp.DSCP
	outIp.ECN = inIp.ECN
	outIp.Length = uint16(20 + outUdp.Len())
	outIp.Id = inIp.Id
	outIp.Flags = inIp.Flags
	outIp.FragmentOffset = inIp.FragmentOffset
	outIp.TTL = 64
	outIp.Protocol = protocol.Type_UDP
	outIp.NWSrc = inIp.NWDst
	outIp.NWDst = inIp.NWSrc
	if d, e := outIp.MarshalBinary(); e != nil {
		return nil, e
	} else {
		outIp.Checksum = ipChecksum(d)
	}
	outIp.Data = outUdp

	outEth := protocol.NewEthernet()
	outEth.VLANID.VID = inEth.VLANID.VID
	outEth.HWDst = inEth.HWSrc
	outEth.HWSrc = inEth.HWDst
	outEth.Ethertype = inEth.Ethertype
	outEth.Data = outIp
	return outEth, nil
}

// createPortVlanFlow creates port vlan flow based on endpoint metadata
func createPortVlanFlow(agent *OfnetAgent, vlanTable, nextTable *ofctrl.Table, endpoint *OfnetEndpoint) (*ofctrl.Flow, error) {
	// Install a flow entry for vlan mapping
	portVlanFlow, err := vlanTable.NewFlow(ofctrl.FlowMatch{
		Priority:  FLOW_FLOOD_PRIORITY,
		InputPort: endpoint.PortNo,
	})
	if err != nil {
		log.Errorf("Error creating portvlan entry. Err: %v", err)
		return nil, err
	}

	//set vrf id as METADATA
	vrfid := agent.getvrfId(endpoint.Vrf)
	metadata, metadataMask := Vrfmetadata(*vrfid)

	// set source EPG id if required
	if endpoint.EndpointGroup != 0 {
		srcMetadata, srcMetadataMask := SrcGroupMetadata(endpoint.EndpointGroup)
		metadata = metadata | srcMetadata
		metadataMask = metadataMask | srcMetadataMask

	}

	// set vlan if required
	if agent.dpName == "vxlan" {
		portVlanFlow.SetVlan(endpoint.Vlan)
	}

	// set metedata
	portVlanFlow.SetMetadata(metadata, metadataMask)

	// Point it to next table
	err = portVlanFlow.Next(nextTable)
	if err != nil {
		log.Errorf("Error installing portvlan entry. Err: %v", err)
		return nil, err
	}

	return portVlanFlow, nil
}

// createDscpFlow creates DSCP v4/v6 flows
func createDscpFlow(agent *OfnetAgent, vlanTable, nextTable *ofctrl.Table, endpoint *OfnetEndpoint) (*ofctrl.Flow, *ofctrl.Flow, error) {
	// if endpoint has no DSCP value, we are done..
	if endpoint.Dscp == 0 {
		return nil, nil, nil
	}

	// Install a flow entry for DSCP v4
	dscpV4Flow, err := vlanTable.NewFlow(ofctrl.FlowMatch{
		Priority:  FLOW_MATCH_PRIORITY,
		InputPort: endpoint.PortNo,
		Ethertype: 0x0800,
	})
	if err != nil {
		log.Errorf("Error creating DSCP v4 entry. Err: %v", err)
		return nil, nil, err
	}

	// Install a flow entry for DSCP v6
	dscpV6Flow, err := vlanTable.NewFlow(ofctrl.FlowMatch{
		Priority:  FLOW_MATCH_PRIORITY,
		InputPort: endpoint.PortNo,
		Ethertype: 0x86DD,
	})
	if err != nil {
		log.Errorf("Error creating DSCP v6 entry. Err: %v", err)
		return nil, nil, err
	}

	//set vrf id as METADATA
	vrfid := agent.getvrfId(endpoint.Vrf)
	metadata, metadataMask := Vrfmetadata(*vrfid)

	// set source EPG id if required
	if endpoint.EndpointGroup != 0 {
		srcMetadata, srcMetadataMask := SrcGroupMetadata(endpoint.EndpointGroup)
		metadata = metadata | srcMetadata
		metadataMask = metadataMask | srcMetadataMask

	}

	// set vlan if required
	if agent.dpName == "vxlan" {
		dscpV4Flow.SetVlan(endpoint.Vlan)
		dscpV6Flow.SetVlan(endpoint.Vlan)
	}

	// set dscp and metadata on the flow
	dscpV4Flow.SetDscp(uint8(endpoint.Dscp))
	dscpV6Flow.SetDscp(uint8(endpoint.Dscp))
	dscpV4Flow.SetMetadata(metadata, metadataMask)
	dscpV6Flow.SetMetadata(metadata, metadataMask)

	// Point it to next table
	err = dscpV4Flow.Next(nextTable)
	if err != nil {
		log.Errorf("Error installing dscp v4 entry. Err: %v", err)
		return nil, nil, err
	}
	err = dscpV6Flow.Next(nextTable)
	if err != nil {
		log.Errorf("Error installing dscp v6 entry. Err: %v", err)
		return nil, nil, err
	}

	return dscpV4Flow, dscpV6Flow, nil
}

// getActiveLink returns an active member link
func (port *PortInfo) getActiveLink(hashParams ...string) *LinkInfo {
	if len(port.ActiveLinks) == 0 {
		return nil
	}

	if len(hashParams) == 0 {
		// If no hash parameters are specified, pick a random link
		return port.ActiveLinks[rand.Intn(len(port.ActiveLinks))]
	} else {
		// Pick an active link based on the hash parameters specified
		var hashBytes []byte
		h := fnv.New32a()
		for _, param := range hashParams {
			hashBytes = append(hashBytes, []byte(param)...)
		}
		h.Write(hashBytes)
		return port.ActiveLinks[h.Sum32()%uint32(len(port.ActiveLinks))]
	}
}

func (port *PortInfo) checkLinkStatus() error {
	port.LinkStatus = linkDown
	for _, link := range port.MbrLinks {
		linkInfo, err := netlink.LinkByName(link.Name)
		if err != nil {
			err := fmt.Errorf("Error getting link information for %+v", link)
			log.Errorf("%+v", err)
			return err
		}
		if linkInfo.Attrs().Flags&net.FlagUp != 0 {
			link.setLinkStatus(linkUp)
			port.LinkStatus = linkUp
		} else {
			link.setLinkStatus(linkDown)
		}
	}

	return nil
}

// handleLacpUpdate
func (link *LinkInfo) handleLacpUpdate(lacpActive bool) {
	log.Infof("Handling LACP update for link: %s, Lacp status: %+v", link.Name, lacpActive)
	port := link.Port
	if !lacpActive {
		for idx, activeLink := range port.ActiveLinks {
			if link == activeLink {
				if idx == (len(port.ActiveLinks) - 1) {
					port.ActiveLinks = port.ActiveLinks[:idx]
				} else {
					port.ActiveLinks = append(port.ActiveLinks[:idx], port.ActiveLinks[idx+1:]...)
				}
				break
			}
		}
	} else {
		for _, activeLink := range port.ActiveLinks {
			if link == activeLink {
				// Link already part of port
				return
			}
		}
		port.ActiveLinks = append(port.ActiveLinks, link)
	}
}

// setLinkStatus sets interface link status and updates active links of the port
func (link *LinkInfo) setLinkStatus(status linkStatus) {
	if link.LinkStatus == status {
		// Duplicate link notification. Nothing to do
		return
	}

	link.LinkStatus = status
	port := link.Port
	if status == linkUp {
		linkExists := false
		for _, activeLink := range port.ActiveLinks {
			if link == activeLink {
				linkExists = true
				break
			}
		}
		if !linkExists {
			port.ActiveLinks = append(port.ActiveLinks, link)
		}
		port.LinkStatus = linkUp
		log.Debugf("Added %+v to port's active links: %+v", link, port)
	} else {
		for idx, activeLink := range port.ActiveLinks {
			if link == activeLink {
				if idx == (len(port.ActiveLinks) - 1) {
					port.ActiveLinks = port.ActiveLinks[:idx]
				} else {
					port.ActiveLinks = append(port.ActiveLinks[:idx], port.ActiveLinks[idx+1:]...)
				}
				if len(port.ActiveLinks) == 0 {
					port.LinkStatus = linkDown
				}
				log.Debugf("Removed %+v from active links in port: %+v", link, port)
				return
			}
		}
	}
}