Reject unvotable tickets.

/payfee and /getaddress will now only accept tickets which are immature or live.

database/database.go

@@ -98,17 +98,17 @@ func Open(ctx context.Context, shutdownWg *sync.WaitGroup, dbFile string, backup
 
 	// Start a ticker to update the backup file at the specified interval.
 	shutdownWg.Add(1)
-	backupTicker := time.NewTicker(backupInterval)
 	go func() {
+		ticker := time.NewTicker(backupInterval)
 		for {
 			select {
-			case <-backupTicker.C:
+			case <-ticker.C:
 				err := writeBackup(db, dbFile)
 				if err != nil {
 					log.Errorf("Failed to write database backup: %v", err)
 				}
 			case <-ctx.Done():
-				backupTicker.Stop()
+				ticker.Stop()
 				shutdownWg.Done()
 				return
 			}

docs/api.md

@@ -48,7 +48,7 @@ its voting wallets unless both of these calls have succeeded.**
 
 Request fee amount and address for a ticket. The fee amount is only valid until
 the expiration time has passed. The fee amount is an absolute value measured in
-DCR.
+DCR. Returns an error if the specified ticket is not currently immature or live.
 
 This call will return an error if a fee transaction has already been provided
 for the specified ticket.
@@ -82,7 +82,8 @@ for the specified ticket.
 Provide the voting key for the ticket, voting preference, and a signed
 transaction which pays the fee to the specified address. If the fee has expired,
 this call will return an error and the client will need to request a new fee by
-calling `/feeaddress` again.
+calling `/feeaddress` again. Returns an error if the specified ticket is not
+currently immature or live.
 
 The VSP will not broadcast the fee transaction until the ticket purchase has 6
 confirmations. For this reason, it is important that the client ensures the

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/decred/slog v1.0.0
 	github.com/gin-gonic/gin v1.6.3
 	github.com/jessevdk/go-flags v1.4.0
+	github.com/jrick/bitset v1.0.0
 	github.com/jrick/logrotate v1.0.0
 	github.com/jrick/wsrpc/v2 v2.3.3
 	go.etcd.io/bbolt v1.3.4

rpc/dcrd.go

@@ -10,6 +10,7 @@ import (
 	"github.com/decred/dcrd/chaincfg/v3"
 	dcrdtypes "github.com/decred/dcrd/rpc/jsonrpc/types/v2"
 	"github.com/decred/dcrd/wire"
+	"github.com/jrick/bitset"
 )
 
 const (
@@ -135,3 +136,47 @@ func (c *DcrdRPC) GetBestBlockHeader() (*dcrdtypes.GetBlockHeaderVerboseResult,
 	}
 	return &blockHeader, nil
 }
+
+func (c *DcrdRPC) ExistsLiveTicket(ticketHash string) (bool, error) {
+	var exists string
+	err := c.Call(c.ctx, "existslivetickets", &exists, []string{ticketHash})
+	if err != nil {
+		return false, err
+	}
+
+	existsBytes := make([]byte, hex.DecodedLen(len(exists)))
+	_, err = hex.Decode(existsBytes, []byte(exists))
+	if err != nil {
+		return false, err
+	}
+
+	return bitset.Bytes(existsBytes).Get(0), nil
+}
+
+// CanTicketVote checks determines whether a ticket is able to vote at some
+// point in the future by checking that it is currently either immature or live.
+func (c *DcrdRPC) CanTicketVote(ticketHash string, netParams *chaincfg.Params) (bool, error) {
+	// Get ticket details.
+	rawTx, err := c.GetRawTransaction(ticketHash)
+	if err != nil {
+		return false, err
+	}
+
+	// Tickets which older than (TicketMaturity+TicketExpiry) are too old to vote.
+	if rawTx.Confirmations > int64(uint32(netParams.TicketMaturity)+netParams.TicketExpiry) {
+		return false, nil
+	}
+
+	// If ticket is currently immature, it will be able to vote in future.
+	if rawTx.Confirmations <= int64(netParams.TicketMaturity) {
+		return true, nil
+	}
+
+	// If ticket is currently live, it will be able to vote in future.
+	live, err := c.ExistsLiveTicket(ticketHash)
+	if err != nil {
+		return false, err
+	}
+
+	return live, nil
+}

webapi/getfeeaddress.go

@@ -81,6 +81,20 @@ func feeAddress(c *gin.Context) {
 		return
 	}
 
+	ticketHash := feeAddressRequest.TicketHash
+
+	canVote, err := dcrdClient.CanTicketVote(ticketHash, cfg.NetParams)
+	if err != nil {
+		log.Errorf("canTicketVote error: %v", err)
+		sendErrorResponse("error validating ticket", http.StatusInternalServerError, c)
+		return
+	}
+	if !canVote {
+		log.Warnf("Unvotable ticket %s from %s", ticketHash, c.ClientIP())
+		sendErrorResponse("ticket not eligible to vote", http.StatusBadRequest, c)
+		return
+	}
+
 	// VSP already knows this ticket and has already issued it a fee address.
 	if knownTicket {
 
@@ -126,29 +140,6 @@ func feeAddress(c *gin.Context) {
 	// Beyond this point we are processing a new ticket which the VSP has not
 	// seen before.
 
-	ticketHash := feeAddressRequest.TicketHash
-
-	// Get transaction details.
-	rawTx, err := dcrdClient.GetRawTransaction(ticketHash)
-	if err != nil {
-		log.Warnf("Could not retrieve tx %s for %s: %v", ticketHash, c.ClientIP(), err)
-		sendErrorResponse("unknown transaction", http.StatusBadRequest, c)
-		return
-	}
-
-	// Don't accept tickets which are too old.
-	if rawTx.Confirmations > int64(uint32(cfg.NetParams.TicketMaturity)+cfg.NetParams.TicketExpiry) {
-		log.Warnf("Too old tx from %s", c.ClientIP())
-		sendErrorResponse("transaction too old", http.StatusBadRequest, c)
-		return
-	}
-
-	// Check if ticket is fully confirmed.
-	var confirmed bool
-	if rawTx.Confirmations >= requiredConfs {
-		confirmed = true
-	}
-
 	fee, err := getCurrentFee(dcrdClient)
 	if err != nil {
 		log.Errorf("getCurrentFee error: %v", err)
@@ -169,7 +160,6 @@ func feeAddress(c *gin.Context) {
 		CommitmentAddress: commitmentAddress,
 		FeeAddressIndex:   newAddressIdx,
 		FeeAddress:        newAddress,
-		Confirmed:         confirmed,
 		FeeAmount:         fee,
 		FeeExpiration:     expire,
 		// VotingKey and VoteChoices: set during payfee
@@ -182,8 +172,8 @@ func feeAddress(c *gin.Context) {
 		return
 	}
 
-	log.Debugf("Fee address created for new ticket: tktConfirmed=%t, feeAddrIdx=%d, "+
-		"feeAddr=%s, feeAmt=%f, ticketHash=%s", confirmed, newAddressIdx, newAddress, fee, ticketHash)
+	log.Debugf("Fee address created for new ticket: feeAddrIdx=%d, feeAddr=%s, "+
+		"feeAmt=%f, ticketHash=%s", newAddressIdx, newAddress, fee, ticketHash)
 
 	sendJSONResponse(feeAddressResponse{
 		Timestamp:  now.Unix(),

webapi/payfee.go

@@ -44,6 +44,18 @@ func payFee(c *gin.Context) {
 		return
 	}
 
+	canVote, err := dcrdClient.CanTicketVote(ticket.Hash, cfg.NetParams)
+	if err != nil {
+		log.Errorf("canTicketVote error: %v", err)
+		sendErrorResponse("error validating ticket", http.StatusInternalServerError, c)
+		return
+	}
+	if !canVote {
+		log.Warnf("Unvotable ticket %s from %s", ticket.Hash, c.ClientIP())
+		sendErrorResponse("ticket not eligible to vote", http.StatusBadRequest, c)
+		return
+	}
+
 	// Respond early if the fee for this ticket is expired.
 	if ticket.FeeExpired() {
 		log.Warnf("Expired payfee request from %s", c.ClientIP())

webapi/webapi.go

@@ -28,9 +28,6 @@ type Config struct {
 }
 
 const (
-	// requiredConfs is the number of confirmations required to consider a
-	// ticket purchase or a fee transaction to be final.
-	requiredConfs = 6
 	// TODO: Make this configurable or get it from RPC.
 	relayFee = 0.0001
 )