zoreide/interface.go

package main

import (
	"fmt"
	"log"
	"math/rand"
	"net"
	"time"

	"github.com/go-ping/ping"

	"github.com/milosgajdos/tenus"
)

func init() {

	ZoreideBridge.initializeHierarchy()

}

func (b *AbstractBridge) RefreshArp() {

	// we want the program to recover in case of issues
	defer func() {
		if r := recover(); r != nil {

			fmt.Println("An error happened in <RefreshARP()>, but Zoreide recovered. ")
			fmt.Println("Error was: ", r)
		}
	}()

	b.GArp = new(Gratuitous)

	var err error
	b.GArp.IP, _, err = net.ParseCIDR(b.BridgeIpCIDR)
	if err != nil {
		log.Println("Error parsing CIDR: ", err.Error())
	}
	b.GArp.IfaceName = b.ExistingInterface
	log.Println("ARP Interface name: ", b.GArp.IfaceName)

	SendGratuitous(b.GArp)

}

func (b *AbstractBridge) initializeHierarchy() {

	b.hIerarchyNumber = rand.Int63()
	log.Println("Initialized host number: ", b.hIerarchyNumber)

}

func (b *AbstractBridge) configureIpAndBridgeUp() {
	// we want the program to recover in case of issues
	defer func() {
		if r := recover(); r != nil {

			fmt.Println("An error happened in <configureIpAndBridgeUp()>, but Zoreide recovered. ")
			fmt.Println("Error was: ", r)
		}
	}()

	// first we check the IP is free. Something weird could have happened in some
	// other server
	brIp, brIpNet, err := net.ParseCIDR(b.BridgeIpCIDR)
	if err != nil {
		log.Println("Error parsing CIDR: ", err.Error())
	}

	br, err := tenus.NewLinkFrom(b.ExistingInterface)
	if err != nil {
		log.Println("Error creating Ethernet Alias: ", err.Error())
		log.Println("Problematic interface: ", b.ExistingInterface)
	}

	if err := br.SetLinkIp(brIp, brIpNet); err != nil {
		log.Println("Error setting UP the IP: ", err.Error())
	} else {
		log.Printf("%s configured with %s\n", b.ExistingInterface, brIp.String())
	}

	// refresh ARP , should not be necessary, but we know, Cisco FA
	b.RefreshArp()
}

func (b *AbstractBridge) removeIPandBridgeInt() {

	// we want the program to recover in case of issues
	defer func() {
		if r := recover(); r != nil {

			fmt.Println("An error happened in <removeIPandBridgeInt()>, but Zoreide recovered. ")
			fmt.Println("Error was: ", r)
		}
	}()

	br, err := tenus.NewLinkFrom(b.ExistingInterface)
	if err != nil {
		log.Println("Error creating Ethernet Handle: ", err.Error())
		log.Println("Problematic interface: ", b.ExistingInterface)

	}

	brIp, brIpNet, err := net.ParseCIDR(b.BridgeIpCIDR)
	if err != nil {
		log.Println("Error parsing CIDR: ", err.Error())
	}
	if err := br.UnsetLinkIp(brIp, brIpNet); err != nil {
		log.Println("Error setting DOWN the IP: ", err.Error())
	}

}

func (b *AbstractBridge) IsActive() bool {

	defer func() {
		if r := recover(); r != nil {
			fmt.Println("An error happened in <WriteNumberToMulticast()>, but Zoreide recovered. ")
			fmt.Println("Error was: ", r)
		}
	}()

	var bridgeip string

	brIp, _, err := net.ParseCIDR(b.BridgeIpCIDR)
	if err != nil {
		log.Println("IsActive : problem parsing the IP/CIDR: ", err.Error())
	} else {
		bridgeip = brIp.String()
	}

	log.Println("Check for active IP: ", bridgeip)

	pinger, err := ping.NewPinger(bridgeip)
	if err != nil {
		log.Println("Unable to ping address: ", bridgeip)
		log.Println("Ping error: " + err.Error())
	}
	// just in case it doesn't stops alone
	defer pinger.Stop()
	pinger.Count = 5
	pinger.Interval = time.Duration(10 * time.Millisecond)
	pinger.Timeout = time.Duration(1 * time.Second)
	pinger.Run() // blocks until finished
	stats := pinger.Statistics()
	log.Println("Ping results for: ", bridgeip)
	log.Printf("%d packet sent, %d packet recv\n", pinger.Count, stats.PacketsRecv)
	log.Println("IsACTIVE: ", stats.PacketsRecv == pinger.Count)

	return stats.PacketsRecv == pinger.Count

}

func (b *AbstractBridge) IsAssigned() bool {

	// we want the program to recover in case of issues
	defer func() {
		if r := recover(); r != nil {

			fmt.Println("An error happened in <IsAssigned()>, but Zoreide recovered. ")
			fmt.Println("Error was: ", r)
		}
	}()

	var (
		ief      *net.Interface
		addrs    []net.Addr
		ipv4Addr net.IP
		err      error
		bridgeip string
	)

	brIp, _, err := net.ParseCIDR(b.BridgeIpCIDR)
	if err != nil {
		log.Println("IsActive : problem parsing the IP/CIDR: ", err.Error())
		return false
	} else {
		bridgeip = brIp.String()
	}

	interfaceName := b.ExistingInterface

	if ief, err = net.InterfaceByName(interfaceName); err != nil { // get interface
		log.Printf("Interface %s does not exist or not manageable\n", interfaceName)
		log.Printf("Error is: %s\n", err.Error())
		return false
	}
	if addrs, err = ief.Addrs(); err != nil { // get addresses
		log.Printf("Cannot read IPs of interface %s\n", interfaceName)
		log.Printf("Error is: %s\n", err.Error())
		return false
	}
	for _, addr := range addrs { // get ipv4 address
		if ipv4Addr = addr.(*net.IPNet).IP.To4(); ipv4Addr != nil {
			log.Printf("Error reading IPs for interface %s\n", interfaceName)
			log.Printf("Error is: %s\n", err.Error())
			break
		}
	}
	if ipv4Addr == nil {
		log.Printf("interface %s don't have an ipv4 address\n", interfaceName)
		return false
	}

	for _, addr := range addrs {
		if addr.String() == bridgeip {
			log.Printf("Ip %s is assigned to interface %s", bridgeip, interfaceName)
			return true
		}
	}

	log.Printf("Ip %s is NOT assigned to interface %s", bridgeip, interfaceName)
	return false
}