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main.go
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main.go
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package main
import (
"bigw-voting/bgw"
"bigw-voting/commands"
"bigw-voting/p2p"
"bigw-voting/shamir"
"bigw-voting/ui"
"bigw-voting/util"
"crypto/sha256"
"encoding/json"
"fmt"
"net"
"os"
"os/signal"
"sort"
"time"
upnp "github.com/huin/goupnp/dcps/internetgateway2"
)
var votepack *Votepack
var localVotes map[string]int
var allVoters []*Voter
var localStatus string
var externalIP string
func main() {
parseCommandline()
votepack = NewVotepackFromFile(flagVotepackFilename)
if flagTrusteeExport {
ExportTrusteeVote()
}
commands.VotepackTrustees = votepack.TrusteeVotes
commands.RegisterAll()
go ui.Start()
defer ui.Stop()
time.Sleep(100 * time.Millisecond)
ui.NewVote(votepack.Candidates, SubmitVotes)
// Find local IP for BGW as well as for UPNP mapping
ifaces, err := net.Interfaces()
if err != nil {
panic(err)
}
var localIP string
for _, i := range ifaces {
addrs, err := i.Addrs()
if err != nil {
panic(err)
}
for _, addr := range addrs {
switch v := addr.(type) {
case *net.IPNet:
if !util.IsPublicIP(v.IP.String()) && v.IP.To4() != nil {
localIP = v.IP.String()
break
}
case *net.IPAddr:
if !util.IsPublicIP(v.IP.String()) && v.IP.To4() != nil {
localIP = v.IP.String()
break
}
}
}
}
if !flagNoUPNP {
clients, _, err := upnp.NewWANIPConnection1Clients()
if err != nil {
panic(err)
}
if len(clients) > 1 {
ui.Stop()
panic("detected multiple gateway devices")
}
if len(clients) < 1 {
util.Warnln("Did not detect any gateway devices, if you are behind a NAT, you cannot act as an intermediate")
}
if len(clients) == 1 {
client := clients[0]
util.Infof("Using local IP %v for port mapping\n", localIP)
// Check for an entry before creating one
intPort, _, _, _, _, err := client.GetSpecificPortMappingEntry("", 42069, "udp")
if intPort != 42069 {
util.Infoln("Creating new port mapping")
// Create a new port mapping allowing all remotes to connect to us on port 42069 for 30 minutes
err = client.AddPortMapping("", 42069, "udp", 42069, localIP, true, "BIGW Voting", 1800)
if err != nil {
panic(err)
}
}
util.Infoln("Port mapping is established")
// Get external IP
externalIP, err = client.GetExternalIPAddress()
if err != nil {
panic(err)
}
util.Infof("Starting intermediate server at external IP: %v:42069\n", externalIP)
}
}
externalIP = flagExternalIP
// Find our public IP
if !util.IsPublicIP(externalIP) {
var extIP string
for _, i := range ifaces {
addrs, err := i.Addrs()
if err != nil {
panic(err)
}
for _, addr := range addrs {
switch v := addr.(type) {
case *net.IPNet:
if util.IsPublicIP(v.IP.String()) {
extIP = v.IP.String()
break
}
case *net.IPAddr:
if util.IsPublicIP(v.IP.String()) {
extIP = v.IP.String()
break
}
}
}
}
externalIP = extIP
}
localStatus = "Voting InProgress"
p2p.Setup(externalIP, NewPeerCallback)
_, err = p2p.StartConnection(fmt.Sprintf("%v:%v", flagIntermediateIP, flagIntermediatePort), flagPeerIP)
if err != nil {
ui.Stop()
panic(err)
}
// Wait for Ctrl-C
quit := make(chan os.Signal, 1)
signal.Notify(quit, os.Interrupt)
<-quit
}
// NewPeerCallback serves as the callback for when new peers are connected.
// It verifies the votepack is consistent and syncs trustee votes.
func NewPeerCallback(p *p2p.Peer) {
// Create voter structure
voter := NewVoter(p)
allVoters = append(allVoters, voter)
// Start a goroutine (one per peer) for a listener
go listener(voter)
// Verify votepack with new peer
util.Infoln("Verifying votepack with new peer")
hash := sha256.Sum256(votepack.Export())
err := p.SendMessage(append([]byte("VotepackVerify "), hash[:]...))
if err != nil {
util.Errorf("Unable to send message to %v, %v\n", p.PeerAddress.IP.String(), err)
}
ui.AddPeerToList(p.PeerAddress.IP.String(), "Votepack Verified")
// Send our current status to the peer
err = p.SendMessage([]byte("StatusUpdate " + localStatus))
if err != nil {
util.Errorf("Unable to send message to %v, %v\n", p.PeerAddress.IP.String(), err)
}
// Update nick for new peer
// if commands.Nick != "" {
// err := p2p.BroadcastMessage([]byte("Nick "+commands.Nick), 0)
// if err != nil {
// util.Errorln(err)
// return
// }
// }
// Update the peer with our trustee votes
for _, v := range commands.LocalTrusteeVotes {
err = p2p.BroadcastMessage([]byte("TrusteeVote "+v.Name), 0)
if err != nil {
util.Errorln(err)
return
}
}
}
// SubmitVotes is the callback for the instantFunoff voting submit button
func SubmitVotes(submittedVotes map[string]int) {
localStatus = "Voting Complete"
localVotes = submittedVotes
// UpdateStatus to all peers
err := p2p.BroadcastMessage([]byte("StatusUpdate "+localStatus), 0)
if err != nil {
util.Errorf("Unable to broadcast status update: %v\n", err)
}
for _, v := range allVoters {
if v.Status != "Voting Complete" {
// Don't begin BGW if peers have not finished voting
return
}
}
// Proceed with BGW
go RunBGW()
}
// RunBGW begins the BGW protocol, with circuits for each round of voting
func RunBGW() {
// A IRV is used to eliminate candidates until there are only 3 left
// https://en.wikipedia.org/wiki/Instant-runoff_voting
// For each round of IRV, the number of votes must be tallied for each candidate.
// This means there must be a BGW circuit for each candidate for each round.
// In a 5 candidate election, that means there must be 5+4 = 9 circuits.
// Create deep copy of elements, so we don't mess up the original candidates
currentCandidates := make([]string, len(votepack.Candidates))
copy(currentCandidates, votepack.Candidates)
sortedPeerIPs := p2p.GetAllPeerIPs()
sort.Strings(sortedPeerIPs)
allPeerIPs := append(sortedPeerIPs, externalIP)
sort.Strings(allPeerIPs)
for len(currentCandidates) > 3 {
// Add votes for each candidate (in alphabetical order)
currentVotes := make(map[string]int)
sort.Strings(currentCandidates)
irvVote := getIRVVote(currentCandidates, localVotes)
// Pre-calculate trustee votes
trusteeVotes := make(map[string]int)
for _, v := range commands.LocalTrusteeVotes {
trusteeIRV := getIRVVote(currentCandidates, v.Votes)
trusteeVotes[trusteeIRV]++
}
for _, v := range currentCandidates {
// Synchronise peers using status
localStatus = "Tallying " + v
err := p2p.BroadcastMessage([]byte("StatusUpdate "+localStatus), 0)
if err != nil {
util.Errorf("Unable to broadcast status update: %v\n", err)
}
for {
var desynchronised bool
for _, v := range allVoters {
if v.Status != localStatus {
desynchronised = true
break
}
}
if !desynchronised {
break
}
}
// Should we vote for this candidate?
shouldVote := 0
util.Infoln("Running tally for", v)
util.Infoln("IRV", irvVote)
if v == irvVote {
util.Infoln("Voting for candidate", v)
shouldVote = 1
}
// Create BGW circuit
head, shares := bgw.NewVotingCircuit(shouldVote+trusteeVotes[v], externalIP, sortedPeerIPs)
// Send shares to peers
for k, v := range shares {
for _, voter := range allVoters {
if voter.Peer.PeerAddress.IP.String() == k {
// Marshal shares
b, err := json.Marshal(v)
if err != nil {
util.Errorln("Unable to marshal peer shares")
}
util.Infoln("Sending:", string(append([]byte("YourShares "), b...)))
err = voter.Peer.SendMessage(append([]byte("YourShares "), b...))
if err != nil {
util.Errorf("Unable to broadcast peer share: %v\n", err)
}
}
}
}
// Wait for all peer shares to be received
for {
if len(receivedPeerShares) == len(sortedPeerIPs) {
break
}
time.Sleep(100 * time.Millisecond)
}
// Sort peer shares then descend circuit
var sortedPeerShares []int
for _, v := range sortedPeerIPs {
sortedPeerShares = append(sortedPeerShares, receivedPeerShares[v]...)
}
util.Infoln("Descending circuit with", sortedPeerShares)
bgw.DescendCircuit(head, sortedPeerShares)
// Get output of circuit and broadcast
circuitOut := head.GetOutput()
util.Infoln("Broadcasting", fmt.Sprintf("MyOutput %v", circuitOut))
err = p2p.BroadcastMessage([]byte(fmt.Sprintf("MyOutput %v", circuitOut)), 0)
if err != nil {
util.Errorf("Unable to broadcast circuit output: %v\n", err)
}
receivedPeerOutputs[externalIP] = circuitOut
// Wait for all peer outputs to be recieved
for {
// Note: allPeerIPs not sortedPeerIPs as we add our result in
if len(receivedPeerOutputs) == len(allPeerIPs) {
break
}
time.Sleep(100 * time.Millisecond)
}
util.Infoln("Local circuit output is", receivedPeerOutputs[externalIP])
// Sort peer outputs then add votes
var sortedPeerOutputs [][2]int
for k, v := range allPeerIPs {
util.Infof("x: %v, peer: %v, peer-out: %v\n", k+1, v, receivedPeerOutputs[v])
sortedPeerOutputs = append(sortedPeerOutputs, [2]int{k + 1, receivedPeerOutputs[v]})
}
util.Infoln("Reconstructing with", sortedPeerOutputs)
currentVotes[v], err = shamir.ReconstructSecret(sortedPeerOutputs)
if err != nil {
util.Errorln("Could not reconstruct circuit output: ", err)
}
util.Infoln("Reconstructed", currentVotes[v])
// Clear all received maps to prevent bad results
receivedPeerOutputs = make(map[string]int)
receivedPeerShares = make(map[string][]int)
}
util.Infoln(currentVotes)
// Ensure that the number of votes does not exceed the number of peers + trustees + us
var numOfVotes int
for _, v := range currentVotes {
numOfVotes += v
}
if numOfVotes > len(p2p.GetAllPeerIPs())+len(commands.AllTrusteeVotes)+1 {
util.Errorln("A peer has voted twice! Number of votes exceeds the number of peer + trustees")
return
}
// Eliminate worst candidate
var worstCandidate string
worstCandidateVotes := -1
for k, v := range currentVotes {
if v < worstCandidateVotes || worstCandidateVotes == -1 {
worstCandidate = k
worstCandidateVotes = currentVotes[k]
}
}
util.Infoln("Eliminating candidate", worstCandidate)
for k, v := range currentCandidates {
if v == worstCandidate {
currentCandidates = append(currentCandidates[:k], currentCandidates[k+1:]...)
}
}
}
util.Infoln("ELECTED CANDIDATES:")
util.Infoln(currentCandidates)
}
// getIRVVote gets the best vote for a given set of candidates
func getIRVVote(currentCandidates []string, votes map[string]int) string {
orderedVotes := make([]string, len(votes))
for k, v := range votes {
orderedVotes[v-1] = k
}
// Find best vote for current candidates
var selected string
for _, v := range orderedVotes {
// Check that candidate voted for is a current candidate
for _, w := range currentCandidates {
if w == v {
selected = v
break
}
}
// If we have found the candidate then we are all good
if selected != "" {
break
}
}
return selected
}