feat: PaychAvailableFunds API method

api/api_full.go

@@ -418,6 +418,7 @@ type FullNode interface {
 
 	PaychGet(ctx context.Context, from, to address.Address, amt types.BigInt) (*ChannelInfo, error)
 	PaychGetWaitReady(context.Context, cid.Cid) (address.Address, error)
+	PaychAvailableFunds(from, to address.Address) (*ChannelAvailableFunds, error)
 	PaychList(context.Context) ([]address.Address, error)
 	PaychStatus(context.Context, address.Address) (*PaychStatus, error)
 	PaychSettle(context.Context, address.Address) (cid.Cid, error)
@@ -426,7 +427,7 @@ type FullNode interface {
 	PaychNewPayment(ctx context.Context, from, to address.Address, vouchers []VoucherSpec) (*PaymentInfo, error)
 	PaychVoucherCheckValid(context.Context, address.Address, *paych.SignedVoucher) error
 	PaychVoucherCheckSpendable(context.Context, address.Address, *paych.SignedVoucher, []byte, []byte) (bool, error)
-	PaychVoucherCreate(context.Context, address.Address, types.BigInt, uint64) (*paych.SignedVoucher, error)
+	PaychVoucherCreate(context.Context, address.Address, types.BigInt, uint64) (*VoucherCreateResult, error)
 	PaychVoucherAdd(context.Context, address.Address, *paych.SignedVoucher, []byte, types.BigInt) (types.BigInt, error)
 	PaychVoucherList(context.Context, address.Address) ([]*paych.SignedVoucher, error)
 	PaychVoucherSubmit(context.Context, address.Address, *paych.SignedVoucher, []byte, []byte) (cid.Cid, error)
@@ -535,6 +536,23 @@ type ChannelInfo struct {
 	WaitSentinel cid.Cid
 }
 
+type ChannelAvailableFunds struct {
+	Channel *address.Address
+	// ConfirmedAmt is the amount of funds that have been confirmed on-chain
+	// for the channel
+	ConfirmedAmt types.BigInt
+	// PendingAmt is the amount of funds that are pending confirmation on-chain
+	PendingAmt types.BigInt
+	// PendingWaitSentinel can be used with PaychGetWaitReady to wait for
+	// confirmation of pending funds
+	PendingWaitSentinel *cid.Cid
+	// QueuedAmt is the amount that is queued up behind a pending request
+	QueuedAmt types.BigInt
+	// VoucherRedeemedAmt is the amount that is redeemed by vouchers on-chain
+	// and in the local datastore
+	VoucherReedeemedAmt types.BigInt
+}
+
 type PaymentInfo struct {
 	Channel      address.Address
 	WaitSentinel cid.Cid
@@ -550,6 +568,16 @@ type VoucherSpec struct {
 	Extra *paych.ModVerifyParams
 }
 
+// VoucherCreateResult is the response to calling PaychVoucherCreate
+type VoucherCreateResult struct {
+	// Voucher that was created, or nil if there was an error or if there
+	// were insufficient funds in the channel
+	Voucher *paych.SignedVoucher
+	// Shortfall is the additional amount that would be needed in the channel
+	// in order to be able to create the voucher
+	Shortfall types.BigInt
+}
+
 type MinerPower struct {
 	MinerPower power.Claim
 	TotalPower power.Claim

api/apistruct/struct.go

@@ -203,6 +203,7 @@ type FullNodeStruct struct {
 
 		PaychGet                   func(ctx context.Context, from, to address.Address, amt types.BigInt) (*api.ChannelInfo, error)           `perm:"sign"`
 		PaychGetWaitReady          func(context.Context, cid.Cid) (address.Address, error)                                                   `perm:"sign"`
+		PaychAvailableFunds        func(address.Address, address.Address) (*api.ChannelAvailableFunds, error)                                `perm:"sign"`
 		PaychList                  func(context.Context) ([]address.Address, error)                                                          `perm:"read"`
 		PaychStatus                func(context.Context, address.Address) (*api.PaychStatus, error)                                          `perm:"read"`
 		PaychSettle                func(context.Context, address.Address) (cid.Cid, error)                                                   `perm:"sign"`
@@ -213,7 +214,7 @@ type FullNodeStruct struct {
 		PaychVoucherCheckValid     func(context.Context, address.Address, *paych.SignedVoucher) error                                        `perm:"read"`
 		PaychVoucherCheckSpendable func(context.Context, address.Address, *paych.SignedVoucher, []byte, []byte) (bool, error)                `perm:"read"`
 		PaychVoucherAdd            func(context.Context, address.Address, *paych.SignedVoucher, []byte, types.BigInt) (types.BigInt, error)  `perm:"write"`
-		PaychVoucherCreate         func(context.Context, address.Address, big.Int, uint64) (*paych.SignedVoucher, error)                     `perm:"sign"`
+		PaychVoucherCreate         func(context.Context, address.Address, big.Int, uint64) (*api.VoucherCreateResult, error)                 `perm:"sign"`
 		PaychVoucherList           func(context.Context, address.Address) ([]*paych.SignedVoucher, error)                                    `perm:"write"`
 		PaychVoucherSubmit         func(context.Context, address.Address, *paych.SignedVoucher, []byte, []byte) (cid.Cid, error)             `perm:"sign"`
 	}
@@ -882,6 +883,10 @@ func (c *FullNodeStruct) PaychGetWaitReady(ctx context.Context, sentinel cid.Cid
 	return c.Internal.PaychGetWaitReady(ctx, sentinel)
 }
 
+func (c *FullNodeStruct) PaychAvailableFunds(from address.Address, to address.Address) (*api.ChannelAvailableFunds, error) {
+	return c.Internal.PaychAvailableFunds(from, to)
+}
+
 func (c *FullNodeStruct) PaychList(ctx context.Context) ([]address.Address, error) {
 	return c.Internal.PaychList(ctx)
 }
@@ -902,7 +907,7 @@ func (c *FullNodeStruct) PaychVoucherAdd(ctx context.Context, addr address.Addre
 	return c.Internal.PaychVoucherAdd(ctx, addr, sv, proof, minDelta)
 }
 
-func (c *FullNodeStruct) PaychVoucherCreate(ctx context.Context, pch address.Address, amt types.BigInt, lane uint64) (*paych.SignedVoucher, error) {
+func (c *FullNodeStruct) PaychVoucherCreate(ctx context.Context, pch address.Address, amt types.BigInt, lane uint64) (*api.VoucherCreateResult, error) {
 	return c.Internal.PaychVoucherCreate(ctx, pch, amt, lane)
 }
 

api/test/paych.go

@@ -96,18 +96,24 @@ func TestPaymentChannels(t *testing.T, b APIBuilder, blocktime time.Duration) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		if vouch1.Voucher == nil {
+			t.Fatal(fmt.Errorf("Not enough funds to create voucher: missing %d", vouch1.Shortfall))
+		}
 		vouch2, err := paymentCreator.PaychVoucherCreate(ctx, channel, abi.NewTokenAmount(2000), lane)
 		if err != nil {
 			t.Fatal(err)
 		}
-		delta1, err := paymentReceiver.PaychVoucherAdd(ctx, channel, vouch1, nil, abi.NewTokenAmount(1000))
+		if vouch2.Voucher == nil {
+			t.Fatal(fmt.Errorf("Not enough funds to create voucher: missing %d", vouch2.Shortfall))
+		}
+		delta1, err := paymentReceiver.PaychVoucherAdd(ctx, channel, vouch1.Voucher, nil, abi.NewTokenAmount(1000))
 		if err != nil {
 			t.Fatal(err)
 		}
 		if !delta1.Equals(abi.NewTokenAmount(1000)) {
 			t.Fatal("voucher didn't have the right amount")
 		}
-		delta2, err := paymentReceiver.PaychVoucherAdd(ctx, channel, vouch2, nil, abi.NewTokenAmount(1000))
+		delta2, err := paymentReceiver.PaychVoucherAdd(ctx, channel, vouch2.Voucher, nil, abi.NewTokenAmount(1000))
 		if err != nil {
 			t.Fatal(err)
 		}

cli/paych.go

@@ -217,9 +217,9 @@ var paychVoucherCreateCmd = &cli.Command{
 			return err
 		}
 
-		amt, err := types.BigFromString(cctx.Args().Get(1))
+		amt, err := types.ParseFIL(cctx.Args().Get(1))
 		if err != nil {
-			return err
+			return ShowHelp(cctx, fmt.Errorf("parsing amount failed: %s", err))
 		}
 
 		lane := cctx.Int("lane")
@@ -232,12 +232,16 @@ var paychVoucherCreateCmd = &cli.Command{
 
 		ctx := ReqContext(cctx)
 
-		sv, err := api.PaychVoucherCreate(ctx, ch, amt, uint64(lane))
+		v, err := api.PaychVoucherCreate(ctx, ch, types.BigInt(amt), uint64(lane))
 		if err != nil {
 			return err
 		}
 
-		enc, err := EncodedString(sv)
+		if v.Voucher == nil {
+			return fmt.Errorf("Could not create voucher: insufficient funds in channel, shortfall: %d", v.Shortfall)
+		}
+
+		enc, err := EncodedString(v.Voucher)
 		if err != nil {
 			return err
 		}

cli/paych_test.go

@@ -6,6 +6,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"regexp"
 	"strconv"
 	"strings"
 	"testing"
@@ -248,6 +249,50 @@ func TestPaymentChannelVouchers(t *testing.T) {
 	checkVoucherOutput(t, bestSpendable, bestVouchers)
 }
 
+// TestPaymentChannelVoucherCreateShortfall verifies that if a voucher amount
+// is greater than what's left in the channel, voucher create fails
+func TestPaymentChannelVoucherCreateShortfall(t *testing.T) {
+	_ = os.Setenv("BELLMAN_NO_GPU", "1")
+
+	blocktime := 5 * time.Millisecond
+	ctx := context.Background()
+	nodes, addrs := startTwoNodesOneMiner(ctx, t, blocktime)
+	paymentCreator := nodes[0]
+	creatorAddr := addrs[0]
+	receiverAddr := addrs[1]
+
+	// Create mock CLI
+	mockCLI := newMockCLI(t)
+	creatorCLI := mockCLI.client(paymentCreator.ListenAddr)
+
+	// creator: paych get <creator> <receiver> <amount>
+	channelAmt := 100
+	cmd := []string{creatorAddr.String(), receiverAddr.String(), fmt.Sprintf("%d", channelAmt)}
+	chstr := creatorCLI.runCmd(paychGetCmd, cmd)
+
+	chAddr, err := address.NewFromString(chstr)
+	require.NoError(t, err)
+
+	// creator: paych voucher create <channel> <amount> --lane=1
+	voucherAmt1 := 60
+	lane1 := "--lane=1"
+	cmd = []string{lane1, chAddr.String(), strconv.Itoa(voucherAmt1)}
+	voucher1 := creatorCLI.runCmd(paychVoucherCreateCmd, cmd)
+	fmt.Println(voucher1)
+
+	// creator: paych voucher create <channel> <amount> --lane=2
+	lane2 := "--lane=2"
+	voucherAmt2 := 70
+	cmd = []string{lane2, chAddr.String(), strconv.Itoa(voucherAmt2)}
+	_, err = creatorCLI.runCmdRaw(paychVoucherCreateCmd, cmd)
+
+	// Should fail because channel doesn't have required amount
+	require.Error(t, err)
+
+	shortfall := voucherAmt1 + voucherAmt2 - channelAmt
+	require.Regexp(t, regexp.MustCompile(fmt.Sprintf("shortfall: %d", shortfall)), err.Error())
+}
+
 func checkVoucherOutput(t *testing.T, list string, vouchers []voucherSpec) {
 	lines := strings.Split(list, "\n")
 	listVouchers := make(map[string]string)
@@ -350,6 +395,13 @@ type mockCLIClient struct {
 }
 
 func (c *mockCLIClient) runCmd(cmd *cli.Command, input []string) string {
+	out, err := c.runCmdRaw(cmd, input)
+	require.NoError(c.t, err)
+
+	return out
+}
+
+func (c *mockCLIClient) runCmdRaw(cmd *cli.Command, input []string) (string, error) {
 	// prepend --api=<node api listener address>
 	apiFlag := "--api=" + c.addr.String()
 	input = append([]string{apiFlag}, input...)
@@ -359,12 +411,11 @@ func (c *mockCLIClient) runCmd(cmd *cli.Command, input []string) string {
 	require.NoError(c.t, err)
 
 	err = cmd.Action(cli.NewContext(c.cctx.App, fs, c.cctx))
-	require.NoError(c.t, err)
 
 	// Get the output
 	str := strings.TrimSpace(c.out.String())
 	c.out.Reset()
-	return str
+	return str, err
 }
 
 func (c *mockCLIClient) flagSet(cmd *cli.Command) *flag.FlagSet {

markets/retrievaladapter/client.go

@@ -3,11 +3,14 @@ package retrievaladapter
 import (
 	"context"
 
+	"golang.org/x/xerrors"
+
+	"github.com/filecoin-project/specs-actors/actors/builtin/paych"
+
 	"github.com/filecoin-project/go-address"
 	"github.com/filecoin-project/go-fil-markets/retrievalmarket"
 	"github.com/filecoin-project/go-fil-markets/shared"
 	"github.com/filecoin-project/specs-actors/actors/abi"
-	"github.com/filecoin-project/specs-actors/actors/builtin/paych"
 	"github.com/ipfs/go-cid"
 	"github.com/multiformats/go-multiaddr"
 
@@ -56,7 +59,10 @@ func (rcn *retrievalClientNode) CreatePaymentVoucher(ctx context.Context, paymen
 	if err != nil {
 		return nil, err
 	}
-	return voucher, nil
+	if voucher.Voucher == nil {
+		return nil, xerrors.Errorf("Could not create voucher - shortfall: %d", voucher.Shortfall)
+	}
+	return voucher.Voucher, nil
 }
 
 func (rcn *retrievalClientNode) GetChainHead(ctx context.Context) (shared.TipSetToken, abi.ChainEpoch, error) {

node/impl/paych/paych.go

@@ -3,9 +3,10 @@ package paych
 import (
 	"context"
 
+	"golang.org/x/xerrors"
+
 	"github.com/ipfs/go-cid"
 	"go.uber.org/fx"
-	"golang.org/x/xerrors"
 
 	"github.com/filecoin-project/go-address"
 	"github.com/filecoin-project/specs-actors/actors/builtin/paych"
@@ -38,6 +39,10 @@ func (a *PaychAPI) PaychGet(ctx context.Context, from, to address.Address, amt t
 	}, nil
 }
 
+func (a *PaychAPI) PaychAvailableFunds(from, to address.Address) (*api.ChannelAvailableFunds, error) {
+	return a.PaychMgr.AvailableFunds(from, to)
+}
+
 func (a *PaychAPI) PaychGetWaitReady(ctx context.Context, sentinel cid.Cid) (address.Address, error) {
 	return a.PaychMgr.GetPaychWaitReady(ctx, sentinel)
 }
@@ -64,9 +69,7 @@ func (a *PaychAPI) PaychNewPayment(ctx context.Context, from, to address.Address
 	svs := make([]*paych.SignedVoucher, len(vouchers))
 
 	for i, v := range vouchers {
-		sv, err := a.paychVoucherCreate(ctx, ch.Channel, paych.SignedVoucher{
+		sv, err := a.PaychMgr.CreateVoucher(ctx, ch.Channel, paych.SignedVoucher{
-			ChannelAddr: ch.Channel,
-
 			Amount: v.Amount,
 			Lane:   lane,
 
@@ -78,8 +81,11 @@ func (a *PaychAPI) PaychNewPayment(ctx context.Context, from, to address.Address
 		if err != nil {
 			return nil, err
 		}
+		if sv.Voucher == nil {
+			return nil, xerrors.Errorf("Could not create voucher - shortfall of %d", sv.Shortfall)
+		}
 
-		svs[i] = sv
+		svs[i] = sv.Voucher
 	}
 
 	return &api.PaymentInfo{
@@ -129,41 +135,10 @@ func (a *PaychAPI) PaychVoucherAdd(ctx context.Context, ch address.Address, sv *
 // that will be used to create the voucher, so if previous vouchers exist, the
 // actual additional value of this voucher will only be the difference between
 // the two.
-func (a *PaychAPI) PaychVoucherCreate(ctx context.Context, pch address.Address, amt types.BigInt, lane uint64) (*paych.SignedVoucher, error) {
+// If there are insufficient funds in the channel to create the voucher,
-	return a.paychVoucherCreate(ctx, pch, paych.SignedVoucher{ChannelAddr: pch, Amount: amt, Lane: lane})
+// returns a nil voucher and the shortfall.
-}
+func (a *PaychAPI) PaychVoucherCreate(ctx context.Context, pch address.Address, amt types.BigInt, lane uint64) (*api.VoucherCreateResult, error) {
-
+	return a.PaychMgr.CreateVoucher(ctx, pch, paych.SignedVoucher{Amount: amt, Lane: lane})
-func (a *PaychAPI) paychVoucherCreate(ctx context.Context, pch address.Address, voucher paych.SignedVoucher) (*paych.SignedVoucher, error) {
-	ci, err := a.PaychMgr.GetChannelInfo(pch)
-	if err != nil {
-		return nil, xerrors.Errorf("get channel info: %w", err)
-	}
-
-	nonce, err := a.PaychMgr.NextNonceForLane(ctx, pch, voucher.Lane)
-	if err != nil {
-		return nil, xerrors.Errorf("getting next nonce for lane: %w", err)
-	}
-
-	sv := &voucher
-	sv.Nonce = nonce
-
-	vb, err := sv.SigningBytes()
-	if err != nil {
-		return nil, err
-	}
-
-	sig, err := a.WalletSign(ctx, ci.Control, vb)
-	if err != nil {
-		return nil, err
-	}
-
-	sv.Signature = sig
-
-	if _, err := a.PaychMgr.AddVoucherOutbound(ctx, pch, sv, nil, types.NewInt(0)); err != nil {
-		return nil, xerrors.Errorf("failed to persist voucher: %w", err)
-	}
-
-	return sv, nil
 }
 
 func (a *PaychAPI) PaychVoucherList(ctx context.Context, pch address.Address) ([]*paych.SignedVoucher, error) {

paychmgr/accessorcache.go

@@ -60,7 +60,7 @@ func (pm *Manager) accessorCacheKey(from address.Address, to address.Address) st
 // access a channel use the same lock (the lock on the accessor)
 func (pm *Manager) addAccessorToCache(from address.Address, to address.Address) *channelAccessor {
 	key := pm.accessorCacheKey(from, to)
-	ca := newChannelAccessor(pm)
+	ca := newChannelAccessor(pm, from, to)
 	// TODO: Use LRU
 	pm.channels[key] = ca
 	return ca

paychmgr/manager.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"sync"
 
+	"github.com/filecoin-project/specs-actors/actors/crypto"
+
 	"github.com/filecoin-project/lotus/node/modules/helpers"
 
 	"github.com/ipfs/go-datastore"
@@ -49,6 +51,7 @@ type paychAPI interface {
 	StateWaitMsg(ctx context.Context, msg cid.Cid, confidence uint64) (*api.MsgLookup, error)
 	MpoolPushMessage(ctx context.Context, msg *types.Message, maxFee *api.MessageSendSpec) (*types.SignedMessage, error)
 	WalletHas(ctx context.Context, addr address.Address) (bool, error)
+	WalletSign(ctx context.Context, k address.Address, msg []byte) (*crypto.Signature, error)
 }
 
 // managerAPI defines all methods needed by the manager
@@ -138,6 +141,15 @@ func (pm *Manager) GetPaych(ctx context.Context, from, to address.Address, amt t
 	return chanAccessor.getPaych(ctx, from, to, amt)
 }
 
+func (pm *Manager) AvailableFunds(from address.Address, to address.Address) (*api.ChannelAvailableFunds, error) {
+	chanAccessor, err := pm.accessorByFromTo(from, to)
+	if err != nil {
+		return nil, err
+	}
+
+	return chanAccessor.availableFunds()
+}
+
 // GetPaychWaitReady waits until the create channel / add funds message with the
 // given message CID arrives.
 // The returned channel address can safely be used against the Manager methods.
@@ -179,6 +191,15 @@ func (pm *Manager) GetChannelInfo(addr address.Address) (*ChannelInfo, error) {
 	return ca.getChannelInfo(addr)
 }
 
+func (pm *Manager) CreateVoucher(ctx context.Context, ch address.Address, voucher paych.SignedVoucher) (*api.VoucherCreateResult, error) {
+	ca, err := pm.accessorByAddress(ch)
+	if err != nil {
+		return nil, err
+	}
+
+	return ca.createVoucher(ctx, ch, voucher)
+}
+
 // CheckVoucherValid checks if the given voucher is valid (is or could become spendable at some point).
 // If the channel is not in the store, fetches the channel from state (and checks that
 // the channel To address is owned by the wallet).
@@ -309,14 +330,6 @@ func (pm *Manager) ListVouchers(ctx context.Context, ch address.Address) ([]*Vou
 	return ca.listVouchers(ctx, ch)
 }
 
-func (pm *Manager) NextNonceForLane(ctx context.Context, ch address.Address, lane uint64) (uint64, error) {
-	ca, err := pm.accessorByAddress(ch)
-	if err != nil {
-		return 0, err
-	}
-	return ca.nextNonceForLane(ctx, ch, lane)
-}
-
 func (pm *Manager) Settle(ctx context.Context, addr address.Address) (cid.Cid, error) {
 	ca, err := pm.accessorByAddress(addr)
 	if err != nil {

paychmgr/mock_test.go

@@ -5,6 +5,10 @@ import (
 	"fmt"
 	"sync"
 
+	"github.com/filecoin-project/lotus/lib/sigs"
+
+	"github.com/filecoin-project/specs-actors/actors/crypto"
+
 	cbornode "github.com/ipfs/go-ipld-cbor"
 
 	"github.com/filecoin-project/specs-actors/actors/util/adt"
@@ -132,6 +136,7 @@ type mockPaychAPI struct {
 	waitingCalls     map[cid.Cid]*waitingCall
 	waitingResponses map[cid.Cid]*waitingResponse
 	wallet           map[address.Address]struct{}
+	signingKey       []byte
 }
 
 func newMockPaychAPI() *mockPaychAPI {
@@ -240,3 +245,17 @@ func (pchapi *mockPaychAPI) addWalletAddress(addr address.Address) {
 
 	pchapi.wallet[addr] = struct{}{}
 }
+
+func (pchapi *mockPaychAPI) WalletSign(ctx context.Context, k address.Address, msg []byte) (*crypto.Signature, error) {
+	pchapi.lk.Lock()
+	defer pchapi.lk.Unlock()
+
+	return sigs.Sign(crypto.SigTypeSecp256k1, pchapi.signingKey, msg)
+}
+
+func (pchapi *mockPaychAPI) addSigningKey(key []byte) {
+	pchapi.lk.Lock()
+	defer pchapi.lk.Unlock()
+
+	pchapi.signingKey = key
+}

paychmgr/paych.go

@@ -5,6 +5,8 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/filecoin-project/lotus/api"
+
 	"github.com/filecoin-project/specs-actors/actors/util/adt"
 
 	"github.com/ipfs/go-cid"
@@ -21,11 +23,36 @@ import (
 	xerrors "golang.org/x/xerrors"
 )
 
+// insufficientFundsErr indicates that there are not enough funds in the
+// channel to create a voucher
+type insufficientFundsErr interface {
+	Shortfall() types.BigInt
+}
+
+type ErrInsufficientFunds struct {
+	shortfall types.BigInt
+}
+
+func newErrInsufficientFunds(shortfall types.BigInt) *ErrInsufficientFunds {
+	return &ErrInsufficientFunds{shortfall: shortfall}
+}
+
+func (e *ErrInsufficientFunds) Error() string {
+	return fmt.Sprintf("not enough funds in channel to cover voucher - shortfall: %d", e.shortfall)
+}
+
+func (e *ErrInsufficientFunds) Shortfall() types.BigInt {
+	return e.shortfall
+}
+
 // channelAccessor is used to simplify locking when accessing a channel
 type channelAccessor struct {
-	// waitCtx is used by processes that wait for things to be confirmed
+	from address.Address
-	// on chain
+	to   address.Address
-	waitCtx       context.Context
+
+	// chctx is used by background processes (eg when waiting for things to be
+	// confirmed on chain)
+	chctx         context.Context
 	sa            *stateAccessor
 	api           managerAPI
 	store         *Store
@@ -34,14 +61,16 @@ type channelAccessor struct {
 	msgListeners  msgListeners
 }
 
-func newChannelAccessor(pm *Manager) *channelAccessor {
+func newChannelAccessor(pm *Manager, from address.Address, to address.Address) *channelAccessor {
 	return &channelAccessor{
-		lk:           &channelLock{globalLock: &pm.lk},
+		from:         from,
+		to:           to,
+		chctx:        pm.ctx,
 		sa:           pm.sa,
 		api:          pm.pchapi,
 		store:        pm.store,
+		lk:           &channelLock{globalLock: &pm.lk},
 		msgListeners: newMsgListeners(),
-		waitCtx:      pm.ctx,
 	}
 }
 
@@ -52,6 +81,69 @@ func (ca *channelAccessor) getChannelInfo(addr address.Address) (*ChannelInfo, e
 	return ca.store.ByAddress(addr)
 }
 
+// createVoucher creates a voucher with the given specification, setting its
+// nonce, signing the voucher and storing it in the local datastore.
+// If there are not enough funds in the channel to create the voucher, returns
+// the shortfall in funds.
+func (ca *channelAccessor) createVoucher(ctx context.Context, ch address.Address, voucher paych.SignedVoucher) (*api.VoucherCreateResult, error) {
+	ca.lk.Lock()
+	defer ca.lk.Unlock()
+
+	// Find the channel for the voucher
+	ci, err := ca.store.ByAddress(ch)
+	if err != nil {
+		return nil, xerrors.Errorf("failed to get channel info by address: %w", err)
+	}
+
+	// Set the voucher channel
+	sv := &voucher
+	sv.ChannelAddr = ch
+
+	// Get the next nonce on the given lane
+	sv.Nonce = ca.nextNonceForLane(ci, voucher.Lane)
+
+	// Sign the voucher
+	vb, err := sv.SigningBytes()
+	if err != nil {
+		return nil, xerrors.Errorf("failed to get voucher signing bytes: %w", err)
+	}
+
+	sig, err := ca.api.WalletSign(ctx, ci.Control, vb)
+	if err != nil {
+		return nil, xerrors.Errorf("failed to sign voucher: %w", err)
+	}
+	sv.Signature = sig
+
+	// Store the voucher
+	if _, err := ca.addVoucherUnlocked(ctx, ch, sv, nil, types.NewInt(0)); err != nil {
+		// If there are not enough funds in the channel to cover the voucher,
+		// return a voucher create result with the shortfall
+		var ife insufficientFundsErr
+		if xerrors.As(err, &ife) {
+			return &api.VoucherCreateResult{
+				Shortfall: ife.Shortfall(),
+			}, nil
+		}
+
+		return nil, xerrors.Errorf("failed to persist voucher: %w", err)
+	}
+
+	return &api.VoucherCreateResult{Voucher: sv, Shortfall: types.NewInt(0)}, nil
+}
+
+func (ca *channelAccessor) nextNonceForLane(ci *ChannelInfo, lane uint64) uint64 {
+	var maxnonce uint64
+	for _, v := range ci.Vouchers {
+		if v.Voucher.Lane == lane {
+			if v.Voucher.Nonce > maxnonce {
+				maxnonce = v.Voucher.Nonce
+			}
+		}
+	}
+
+	return maxnonce + 1
+}
+
 func (ca *channelAccessor) checkVoucherValid(ctx context.Context, ch address.Address, sv *paych.SignedVoucher) (map[uint64]*paych.LaneState, error) {
 	ca.lk.Lock()
 	defer ca.lk.Unlock()
@@ -133,7 +225,7 @@ func (ca *channelAccessor) checkVoucherValidUnlocked(ctx context.Context, ch add
 	// Must not exceed actor balance
 	newTotal := types.BigAdd(totalRedeemed, pchState.ToSend)
 	if act.Balance.LessThan(newTotal) {
-		return nil, fmt.Errorf("not enough funds in channel to cover voucher")
+		return nil, newErrInsufficientFunds(types.BigSub(newTotal, act.Balance))
 	}
 
 	if len(sv.Merges) != 0 {
@@ -221,6 +313,10 @@ func (ca *channelAccessor) addVoucher(ctx context.Context, ch address.Address, s
 	ca.lk.Lock()
 	defer ca.lk.Unlock()
 
+	return ca.addVoucherUnlocked(ctx, ch, sv, proof, minDelta)
+}
+
+func (ca *channelAccessor) addVoucherUnlocked(ctx context.Context, ch address.Address, sv *paych.SignedVoucher, proof []byte, minDelta types.BigInt) (types.BigInt, error) {
 	ci, err := ca.store.ByAddress(ch)
 	if err != nil {
 		return types.BigInt{}, err
@@ -382,28 +478,6 @@ func (ca *channelAccessor) listVouchers(ctx context.Context, ch address.Address)
 	return ca.store.VouchersForPaych(ch)
 }
 
-func (ca *channelAccessor) nextNonceForLane(ctx context.Context, ch address.Address, lane uint64) (uint64, error) {
-	ca.lk.Lock()
-	defer ca.lk.Unlock()
-
-	// TODO: should this take into account lane state?
-	vouchers, err := ca.store.VouchersForPaych(ch)
-	if err != nil {
-		return 0, err
-	}
-
-	var maxnonce uint64
-	for _, v := range vouchers {
-		if v.Voucher.Lane == lane {
-			if v.Voucher.Nonce > maxnonce {
-				maxnonce = v.Voucher.Nonce
-			}
-		}
-	}
-
-	return maxnonce + 1, nil
-}
-
 // laneState gets the LaneStates from chain, then applies all vouchers in
 // the data store over the chain state
 func (ca *channelAccessor) laneState(ctx context.Context, state *paych.State, ch address.Address) (map[uint64]*paych.LaneState, error) {
@@ -479,7 +553,7 @@ func (ca *channelAccessor) totalRedeemedWithVoucher(laneStates map[uint64]*paych
 	lane, ok := laneStates[sv.Lane]
 	if ok {
 		// If the voucher is for an existing lane, and the voucher nonce
-		// and is higher than the lane nonce
+		// is higher than the lane nonce
 		if sv.Nonce > lane.Nonce {
 			// Add the delta between the redeemed amount and the voucher
 			// amount to the total

paychmgr/paych_test.go

@@ -381,11 +381,76 @@ func TestCheckVoucherValidCountingAllLanes(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestCreateVoucher(t *testing.T) {
+	ctx := context.Background()
+
+	// Set up a manager with a single payment channel
+	s := testSetupMgrWithChannel(ctx, t)
+
+	// Create a voucher in lane 1
+	voucherLane1Amt := big.NewInt(5)
+	voucher := paych.SignedVoucher{
+		Lane:   1,
+		Amount: voucherLane1Amt,
+	}
+	res, err := s.mgr.CreateVoucher(ctx, s.ch, voucher)
+	require.NoError(t, err)
+	require.NotNil(t, res.Voucher)
+	require.Equal(t, s.ch, res.Voucher.ChannelAddr)
+	require.Equal(t, voucherLane1Amt, res.Voucher.Amount)
+	require.EqualValues(t, 0, res.Shortfall.Int64())
+
+	nonce := res.Voucher.Nonce
+
+	// Create a voucher in lane 1 again, with a higher amount
+	voucherLane1Amt = big.NewInt(8)
+	voucher = paych.SignedVoucher{
+		Lane:   1,
+		Amount: voucherLane1Amt,
+	}
+	res, err = s.mgr.CreateVoucher(ctx, s.ch, voucher)
+	require.NoError(t, err)
+	require.NotNil(t, res.Voucher)
+	require.Equal(t, s.ch, res.Voucher.ChannelAddr)
+	require.Equal(t, voucherLane1Amt, res.Voucher.Amount)
+	require.EqualValues(t, 0, res.Shortfall.Int64())
+	require.Equal(t, nonce+1, res.Voucher.Nonce)
+
+	// Create a voucher in lane 2 that covers all the remaining funds
+	// in the channel
+	voucherLane2Amt := big.Sub(s.amt, voucherLane1Amt)
+	voucher = paych.SignedVoucher{
+		Lane:   2,
+		Amount: voucherLane2Amt,
+	}
+	res, err = s.mgr.CreateVoucher(ctx, s.ch, voucher)
+	require.NoError(t, err)
+	require.NotNil(t, res.Voucher)
+	require.Equal(t, s.ch, res.Voucher.ChannelAddr)
+	require.Equal(t, voucherLane2Amt, res.Voucher.Amount)
+	require.EqualValues(t, 0, res.Shortfall.Int64())
+
+	// Create a voucher in lane 2 that exceeds the remaining funds in the
+	// channel
+	voucherLane2Amt = big.Add(voucherLane2Amt, big.NewInt(1))
+	voucher = paych.SignedVoucher{
+		Lane:   2,
+		Amount: voucherLane2Amt,
+	}
+	res, err = s.mgr.CreateVoucher(ctx, s.ch, voucher)
+	require.NoError(t, err)
+
+	// Expect a shortfall value equal to the amount required to add the voucher
+	// to the channel
+	require.Nil(t, res.Voucher)
+	require.EqualValues(t, 1, res.Shortfall.Int64())
+}
+
 func TestAddVoucherDelta(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, _, ch, fromKeyPrivate := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	voucherLane := uint64(1)
 
@@ -393,23 +458,23 @@ func TestAddVoucherDelta(t *testing.T) {
 	minDelta := big.NewInt(2)
 	nonce := uint64(1)
 	voucherAmount := big.NewInt(1)
-	sv := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err := mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	_, err := s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.Error(t, err)
 
 	// Expect success when adding a voucher whose amount is equal to minDelta
 	nonce++
 	voucherAmount = big.NewInt(2)
-	sv = createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv = createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	delta, err := mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	delta, err := s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 	require.EqualValues(t, delta.Int64(), 2)
 
 	// Check that delta is correct when there's an existing voucher
 	nonce++
 	voucherAmount = big.NewInt(5)
-	sv = createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv = createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	delta, err = mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	delta, err = s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 	require.EqualValues(t, delta.Int64(), 3)
 
@@ -417,8 +482,8 @@ func TestAddVoucherDelta(t *testing.T) {
 	nonce = uint64(1)
 	voucherAmount = big.NewInt(6)
 	voucherLane = uint64(2)
-	sv = createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv = createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	delta, err = mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	delta, err = s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 	require.EqualValues(t, delta.Int64(), 6)
 }
@@ -427,7 +492,7 @@ func TestAddVoucherNextLane(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, _, ch, fromKeyPrivate := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	minDelta := big.NewInt(0)
 	voucherAmount := big.NewInt(2)
@@ -435,40 +500,40 @@ func TestAddVoucherNextLane(t *testing.T) {
 	// Add a voucher in lane 2
 	nonce := uint64(1)
 	voucherLane := uint64(2)
-	sv := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err := mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	_, err := s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 
-	ci, err := mgr.GetChannelInfo(ch)
+	ci, err := s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, ci.NextLane, 3)
 
 	// Allocate a lane (should be lane 3)
-	lane, err := mgr.AllocateLane(ch)
+	lane, err := s.mgr.AllocateLane(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, lane, 3)
 
-	ci, err = mgr.GetChannelInfo(ch)
+	ci, err = s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, ci.NextLane, 4)
 
 	// Add a voucher in lane 1
 	voucherLane = uint64(1)
-	sv = createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv = createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err = mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	_, err = s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 
-	ci, err = mgr.GetChannelInfo(ch)
+	ci, err = s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, ci.NextLane, 4)
 
 	// Add a voucher in lane 7
 	voucherLane = uint64(7)
-	sv = createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv = createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err = mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	_, err = s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 
-	ci, err = mgr.GetChannelInfo(ch)
+	ci, err = s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, ci.NextLane, 8)
 }
@@ -477,15 +542,15 @@ func TestAllocateLane(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, _, ch, _ := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	// First lane should be 0
-	lane, err := mgr.AllocateLane(ch)
+	lane, err := s.mgr.AllocateLane(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, lane, 0)
 
 	// Next lane should be 1
-	lane, err = mgr.AllocateLane(ch)
+	lane, err = s.mgr.AllocateLane(s.ch)
 	require.NoError(t, err)
 	require.EqualValues(t, lane, 1)
 }
@@ -553,7 +618,7 @@ func TestAddVoucherProof(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, _, ch, fromKeyPrivate := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	nonce := uint64(1)
 	voucherAmount := big.NewInt(1)
@@ -563,34 +628,34 @@ func TestAddVoucherProof(t *testing.T) {
 
 	// Add a voucher with no proof
 	var proof []byte
-	sv := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	sv := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err := mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
+	_, err := s.mgr.AddVoucherOutbound(ctx, s.ch, sv, nil, minDelta)
 	require.NoError(t, err)
 
 	// Expect one voucher with no proof
-	ci, err := mgr.GetChannelInfo(ch)
+	ci, err := s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.Len(t, ci.Vouchers, 1)
 	require.Len(t, ci.Vouchers[0].Proof, 0)
 
 	// Add same voucher with no proof
 	voucherLane = uint64(1)
-	_, err = mgr.AddVoucherOutbound(ctx, ch, sv, proof, minDelta)
+	_, err = s.mgr.AddVoucherOutbound(ctx, s.ch, sv, proof, minDelta)
 	require.NoError(t, err)
 
 	// Expect one voucher with no proof
-	ci, err = mgr.GetChannelInfo(ch)
+	ci, err = s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.Len(t, ci.Vouchers, 1)
 	require.Len(t, ci.Vouchers[0].Proof, 0)
 
 	// Add same voucher with proof
 	proof = []byte{1}
-	_, err = mgr.AddVoucherOutbound(ctx, ch, sv, proof, minDelta)
+	_, err = s.mgr.AddVoucherOutbound(ctx, s.ch, sv, proof, minDelta)
 	require.NoError(t, err)
 
 	// Should add proof to existing voucher
-	ci, err = mgr.GetChannelInfo(ch)
+	ci, err = s.mgr.GetChannelInfo(s.ch)
 	require.NoError(t, err)
 	require.Len(t, ci.Vouchers, 1)
 	require.Len(t, ci.Vouchers[0].Proof, 1)
@@ -663,47 +728,47 @@ func TestBestSpendable(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, mock, ch, fromKeyPrivate := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	// Add vouchers to lane 1 with amounts: [1, 2, 3]
 	voucherLane := uint64(1)
 	minDelta := big.NewInt(0)
 	nonce := uint64(1)
 	voucherAmount := big.NewInt(1)
-	svL1V1 := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	svL1V1 := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err := mgr.AddVoucherInbound(ctx, ch, svL1V1, nil, minDelta)
+	_, err := s.mgr.AddVoucherInbound(ctx, s.ch, svL1V1, nil, minDelta)
 	require.NoError(t, err)
 
 	nonce++
 	voucherAmount = big.NewInt(2)
-	svL1V2 := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	svL1V2 := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err = mgr.AddVoucherInbound(ctx, ch, svL1V2, nil, minDelta)
+	_, err = s.mgr.AddVoucherInbound(ctx, s.ch, svL1V2, nil, minDelta)
 	require.NoError(t, err)
 
 	nonce++
 	voucherAmount = big.NewInt(3)
-	svL1V3 := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	svL1V3 := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err = mgr.AddVoucherInbound(ctx, ch, svL1V3, nil, minDelta)
+	_, err = s.mgr.AddVoucherInbound(ctx, s.ch, svL1V3, nil, minDelta)
 	require.NoError(t, err)
 
 	// Add voucher to lane 2 with amounts: [2]
 	voucherLane = uint64(2)
 	nonce = uint64(1)
 	voucherAmount = big.NewInt(2)
-	svL2V1 := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	svL2V1 := createTestVoucher(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err = mgr.AddVoucherInbound(ctx, ch, svL2V1, nil, minDelta)
+	_, err = s.mgr.AddVoucherInbound(ctx, s.ch, svL2V1, nil, minDelta)
 	require.NoError(t, err)
 
 	// Return success exit code from calls to check if voucher is spendable
-	bsapi := newMockBestSpendableAPI(mgr)
+	bsapi := newMockBestSpendableAPI(s.mgr)
-	mock.setCallResponse(&api.InvocResult{
+	s.mock.setCallResponse(&api.InvocResult{
 		MsgRct: &types.MessageReceipt{
 			ExitCode: 0,
 		},
 	})
 
 	// Verify best spendable vouchers on each lane
-	vouchers, err := BestSpendableByLane(ctx, bsapi, ch)
+	vouchers, err := BestSpendableByLane(ctx, bsapi, s.ch)
 	require.NoError(t, err)
 	require.Len(t, vouchers, 2)
 
@@ -716,21 +781,21 @@ func TestBestSpendable(t *testing.T) {
 	require.EqualValues(t, 2, vchr.Amount.Int64())
 
 	// Submit voucher from lane 2
-	_, err = mgr.SubmitVoucher(ctx, ch, svL2V1, nil, nil)
+	_, err = s.mgr.SubmitVoucher(ctx, s.ch, svL2V1, nil, nil)
 	require.NoError(t, err)
 
 	// Best spendable voucher should no longer include lane 2
 	// (because voucher has not been submitted)
-	vouchers, err = BestSpendableByLane(ctx, bsapi, ch)
+	vouchers, err = BestSpendableByLane(ctx, bsapi, s.ch)
 	require.NoError(t, err)
 	require.Len(t, vouchers, 1)
 
 	// Submit first voucher from lane 1
-	_, err = mgr.SubmitVoucher(ctx, ch, svL1V1, nil, nil)
+	_, err = s.mgr.SubmitVoucher(ctx, s.ch, svL1V1, nil, nil)
 	require.NoError(t, err)
 
 	// Best spendable voucher for lane 1 should still be highest value voucher
-	vouchers, err = BestSpendableByLane(ctx, bsapi, ch)
+	vouchers, err = BestSpendableByLane(ctx, bsapi, s.ch)
 	require.NoError(t, err)
 	require.Len(t, vouchers, 1)
 
@@ -743,18 +808,18 @@ func TestCheckSpendable(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, mock, ch, fromKeyPrivate := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	// Create voucher with Extra
 	voucherLane := uint64(1)
 	nonce := uint64(1)
 	voucherAmount := big.NewInt(1)
-	voucher := createTestVoucherWithExtra(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	voucher := createTestVoucherWithExtra(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
 
 	// Add voucher with proof
 	minDelta := big.NewInt(0)
 	proof := []byte("proof")
-	_, err := mgr.AddVoucherInbound(ctx, ch, voucher, proof, minDelta)
+	_, err := s.mgr.AddVoucherInbound(ctx, s.ch, voucher, proof, minDelta)
 	require.NoError(t, err)
 
 	// Return success exit code from VM call, which indicates that voucher is
@@ -764,17 +829,17 @@ func TestCheckSpendable(t *testing.T) {
 			ExitCode: 0,
 		},
 	}
-	mock.setCallResponse(successResponse)
+	s.mock.setCallResponse(successResponse)
 
 	// Check that spendable is true
 	secret := []byte("secret")
 	otherProof := []byte("other proof")
-	spendable, err := mgr.CheckVoucherSpendable(ctx, ch, voucher, secret, otherProof)
+	spendable, err := s.mgr.CheckVoucherSpendable(ctx, s.ch, voucher, secret, otherProof)
 	require.NoError(t, err)
 	require.True(t, spendable)
 
 	// Check that the secret and proof were passed through correctly
-	lastCall := mock.getLastCall()
+	lastCall := s.mock.getLastCall()
 	var p paych.UpdateChannelStateParams
 	err = p.UnmarshalCBOR(bytes.NewReader(lastCall.Params))
 	require.NoError(t, err)
@@ -784,11 +849,11 @@ func TestCheckSpendable(t *testing.T) {
 	// Check that if no proof is supplied, the proof supplied to add voucher
 	// above is used
 	secret2 := []byte("secret2")
-	spendable, err = mgr.CheckVoucherSpendable(ctx, ch, voucher, secret2, nil)
+	spendable, err = s.mgr.CheckVoucherSpendable(ctx, s.ch, voucher, secret2, nil)
 	require.NoError(t, err)
 	require.True(t, spendable)
 
-	lastCall = mock.getLastCall()
+	lastCall = s.mock.getLastCall()
 	var p2 paych.UpdateChannelStateParams
 	err = p2.UnmarshalCBOR(bytes.NewReader(lastCall.Params))
 	require.NoError(t, err)
@@ -796,26 +861,26 @@ func TestCheckSpendable(t *testing.T) {
 	require.Equal(t, secret2, p2.Secret)
 
 	// Check that if VM call returns non-success exit code, spendable is false
-	mock.setCallResponse(&api.InvocResult{
+	s.mock.setCallResponse(&api.InvocResult{
 		MsgRct: &types.MessageReceipt{
 			ExitCode: 1,
 		},
 	})
-	spendable, err = mgr.CheckVoucherSpendable(ctx, ch, voucher, secret, nil)
+	spendable, err = s.mgr.CheckVoucherSpendable(ctx, s.ch, voucher, secret, nil)
 	require.NoError(t, err)
 	require.False(t, spendable)
 
 	// Return success exit code (indicating voucher is spendable)
-	mock.setCallResponse(successResponse)
+	s.mock.setCallResponse(successResponse)
-	spendable, err = mgr.CheckVoucherSpendable(ctx, ch, voucher, secret, nil)
+	spendable, err = s.mgr.CheckVoucherSpendable(ctx, s.ch, voucher, secret, nil)
 	require.NoError(t, err)
 	require.True(t, spendable)
 
 	// Check that voucher is no longer spendable once it has been submitted
-	_, err = mgr.SubmitVoucher(ctx, ch, voucher, nil, nil)
+	_, err = s.mgr.SubmitVoucher(ctx, s.ch, voucher, nil, nil)
 	require.NoError(t, err)
 
-	spendable, err = mgr.CheckVoucherSpendable(ctx, ch, voucher, secret, nil)
+	spendable, err = s.mgr.CheckVoucherSpendable(ctx, s.ch, voucher, secret, nil)
 	require.NoError(t, err)
 	require.False(t, spendable)
 }
@@ -824,28 +889,28 @@ func TestSubmitVoucher(t *testing.T) {
 	ctx := context.Background()
 
 	// Set up a manager with a single payment channel
-	mgr, mock, ch, fromKeyPrivate := testSetupMgrWithChannel(ctx, t)
+	s := testSetupMgrWithChannel(ctx, t)
 
 	// Create voucher with Extra
 	voucherLane := uint64(1)
 	nonce := uint64(1)
 	voucherAmount := big.NewInt(1)
-	voucher := createTestVoucherWithExtra(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	voucher := createTestVoucherWithExtra(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
 
 	// Add voucher with proof
 	minDelta := big.NewInt(0)
 	addVoucherProof := []byte("proof")
-	_, err := mgr.AddVoucherInbound(ctx, ch, voucher, addVoucherProof, minDelta)
+	_, err := s.mgr.AddVoucherInbound(ctx, s.ch, voucher, addVoucherProof, minDelta)
 	require.NoError(t, err)
 
 	// Submit voucher
 	secret := []byte("secret")
 	submitProof := []byte("submit proof")
-	submitCid, err := mgr.SubmitVoucher(ctx, ch, voucher, secret, submitProof)
+	submitCid, err := s.mgr.SubmitVoucher(ctx, s.ch, voucher, secret, submitProof)
 	require.NoError(t, err)
 
 	// Check that the secret and proof were passed through correctly
-	msg := mock.pushedMessages(submitCid)
+	msg := s.mock.pushedMessages(submitCid)
 	var p paych.UpdateChannelStateParams
 	err = p.UnmarshalCBOR(bytes.NewReader(msg.Message.Params))
 	require.NoError(t, err)
@@ -858,14 +923,14 @@ func TestSubmitVoucher(t *testing.T) {
 	voucherAmount = big.NewInt(2)
 	addVoucherProof2 := []byte("proof2")
 	secret2 := []byte("secret2")
-	voucher = createTestVoucherWithExtra(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	voucher = createTestVoucherWithExtra(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	_, err = mgr.AddVoucherInbound(ctx, ch, voucher, addVoucherProof2, minDelta)
+	_, err = s.mgr.AddVoucherInbound(ctx, s.ch, voucher, addVoucherProof2, minDelta)
 	require.NoError(t, err)
 
-	submitCid, err = mgr.SubmitVoucher(ctx, ch, voucher, secret2, nil)
+	submitCid, err = s.mgr.SubmitVoucher(ctx, s.ch, voucher, secret2, nil)
 	require.NoError(t, err)
 
-	msg = mock.pushedMessages(submitCid)
+	msg = s.mock.pushedMessages(submitCid)
 	var p2 paych.UpdateChannelStateParams
 	err = p2.UnmarshalCBOR(bytes.NewReader(msg.Message.Params))
 	require.NoError(t, err)
@@ -877,11 +942,11 @@ func TestSubmitVoucher(t *testing.T) {
 	voucherAmount = big.NewInt(3)
 	secret3 := []byte("secret2")
 	proof3 := []byte("proof3")
-	voucher = createTestVoucherWithExtra(t, ch, voucherLane, nonce, voucherAmount, fromKeyPrivate)
+	voucher = createTestVoucherWithExtra(t, s.ch, voucherLane, nonce, voucherAmount, s.fromKeyPrivate)
-	submitCid, err = mgr.SubmitVoucher(ctx, ch, voucher, secret3, proof3)
+	submitCid, err = s.mgr.SubmitVoucher(ctx, s.ch, voucher, secret3, proof3)
 	require.NoError(t, err)
 
-	msg = mock.pushedMessages(submitCid)
+	msg = s.mock.pushedMessages(submitCid)
 	var p3 paych.UpdateChannelStateParams
 	err = p3.UnmarshalCBOR(bytes.NewReader(msg.Message.Params))
 	require.NoError(t, err)
@@ -889,7 +954,7 @@ func TestSubmitVoucher(t *testing.T) {
 	require.Equal(t, secret3, p3.Secret)
 
 	// Verify that vouchers are marked as submitted
-	vis, err := mgr.ListVouchers(ctx, ch)
+	vis, err := s.mgr.ListVouchers(ctx, s.ch)
 	require.NoError(t, err)
 	require.Len(t, vis, 3)
 
@@ -898,55 +963,20 @@ func TestSubmitVoucher(t *testing.T) {
 	}
 
 	// Attempting to submit the same voucher again should fail
-	_, err = mgr.SubmitVoucher(ctx, ch, voucher, secret2, nil)
+	_, err = s.mgr.SubmitVoucher(ctx, s.ch, voucher, secret2, nil)
 	require.Error(t, err)
 }
 
-func TestNextNonceForLane(t *testing.T) {
+type testScaffold struct {
-	ctx := context.Background()
+	mgr            *Manager
-
+	mock           *mockManagerAPI
-	// Set up a manager with a single payment channel
+	ch             address.Address
-	mgr, _, ch, key := testSetupMgrWithChannel(ctx, t)
+	amt            big.Int
-
+	fromAcct       address.Address
-	// Expect next nonce for non-existent lane to be 1
+	fromKeyPrivate []byte
-	next, err := mgr.NextNonceForLane(ctx, ch, 1)
-	require.NoError(t, err)
-	require.EqualValues(t, next, 1)
-
-	voucherAmount := big.NewInt(1)
-	minDelta := big.NewInt(0)
-	voucherAmount = big.NewInt(2)
-
-	// Add vouchers such that we have
-	// lane 1: nonce 2
-	// lane 1: nonce 4
-	voucherLane := uint64(1)
-	for _, nonce := range []uint64{2, 4} {
-		voucherAmount = big.Add(voucherAmount, big.NewInt(1))
-		sv := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, key)
-		_, err := mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
-		require.NoError(t, err)
 }
 
-	// lane 2: nonce 7
+func testSetupMgrWithChannel(ctx context.Context, t *testing.T) *testScaffold {
-	voucherLane = uint64(2)
-	nonce := uint64(7)
-	sv := createTestVoucher(t, ch, voucherLane, nonce, voucherAmount, key)
-	_, err = mgr.AddVoucherOutbound(ctx, ch, sv, nil, minDelta)
-	require.NoError(t, err)
-
-	// Expect next nonce for lane 1 to be 5
-	next, err = mgr.NextNonceForLane(ctx, ch, 1)
-	require.NoError(t, err)
-	require.EqualValues(t, next, 5)
-
-	// Expect next nonce for lane 2 to be 8
-	next, err = mgr.NextNonceForLane(ctx, ch, 2)
-	require.NoError(t, err)
-	require.EqualValues(t, next, 8)
-}
-
-func testSetupMgrWithChannel(ctx context.Context, t *testing.T) (*Manager, *mockManagerAPI, address.Address, []byte) {
 	fromKeyPrivate, fromKeyPublic := testGenerateKeyPair(t)
 
 	ch := tutils.NewIDAddr(t, 100)
@@ -962,11 +992,12 @@ func testSetupMgrWithChannel(ctx context.Context, t *testing.T) (*Manager, *mock
 	mock.setAccountState(toAcct, account.State{Address: to})
 
 	// Create channel in state
+	balance := big.NewInt(20)
 	act := &types.Actor{
 		Code:    builtin.AccountActorCodeID,
 		Head:    cid.Cid{},
 		Nonce:   0,
-		Balance: big.NewInt(20),
+		Balance: balance,
 	}
 	mock.setPaychState(ch, act, paych.State{
 		From:            fromAcct,
@@ -991,7 +1022,17 @@ func testSetupMgrWithChannel(ctx context.Context, t *testing.T) (*Manager, *mock
 	err = mgr.store.putChannelInfo(ci)
 	require.NoError(t, err)
 
-	return mgr, mock, ch, fromKeyPrivate
+	// Add the from signing key to the wallet
+	mock.addSigningKey(fromKeyPrivate)
+
+	return &testScaffold{
+		mgr:            mgr,
+		mock:           mock,
+		ch:             ch,
+		amt:            balance,
+		fromAcct:       fromAcct,
+		fromKeyPrivate: fromKeyPrivate,
+	}
 }
 
 func testGenerateKeyPair(t *testing.T) ([]byte, []byte) {

paychmgr/paychget_test.go

@@ -6,6 +6,12 @@ import (
 	"testing"
 	"time"
 
+	"github.com/filecoin-project/specs-actors/actors/builtin/account"
+	"github.com/filecoin-project/specs-actors/actors/util/adt"
+
+	"github.com/filecoin-project/specs-actors/actors/abi"
+	"github.com/filecoin-project/specs-actors/actors/builtin/paych"
+
 	cborrpc "github.com/filecoin-project/go-cbor-util"
 
 	init_ "github.com/filecoin-project/specs-actors/actors/builtin/init"
@@ -650,8 +656,6 @@ func TestPaychGetMergeAddFunds(t *testing.T) {
 	require.NoError(t, err)
 
 	// Queue up two add funds requests behind create channel
-	//var addFundsQueuedUp sync.WaitGroup
-	//addFundsQueuedUp.Add(2)
 	var addFundsSent sync.WaitGroup
 	addFundsSent.Add(2)
 
@@ -662,7 +666,6 @@ func TestPaychGetMergeAddFunds(t *testing.T) {
 	var addFundsMcid1 cid.Cid
 	var addFundsMcid2 cid.Cid
 	go func() {
-		//go addFundsQueuedUp.Done()
 		defer addFundsSent.Done()
 
 		// Request add funds - should block until create channel has completed
@@ -671,7 +674,6 @@ func TestPaychGetMergeAddFunds(t *testing.T) {
 	}()
 
 	go func() {
-		//go addFundsQueuedUp.Done()
 		defer addFundsSent.Done()
 
 		// Request add funds again - should merge with waiting add funds request
@@ -899,6 +901,168 @@ func TestPaychGetMergeAddFundsCtxCancelAll(t *testing.T) {
 	require.Equal(t, createAmt, createMsg.Message.Value)
 }
 
+// TestPaychAvailableFunds tests that PaychAvailableFunds returns the correct
+// channel state
+func TestPaychAvailableFunds(t *testing.T) {
+	ctx := context.Background()
+	store := NewStore(ds_sync.MutexWrap(ds.NewMapDatastore()))
+
+	fromKeyPrivate, fromKeyPublic := testGenerateKeyPair(t)
+	ch := tutils.NewIDAddr(t, 100)
+	from := tutils.NewSECP256K1Addr(t, string(fromKeyPublic))
+	to := tutils.NewIDAddr(t, 102)
+	fromAcct := tutils.NewActorAddr(t, "fromAct")
+	toAcct := tutils.NewActorAddr(t, "toAct")
+
+	mock := newMockManagerAPI()
+	defer mock.close()
+
+	mgr, err := newManager(store, mock)
+	require.NoError(t, err)
+
+	// No channel created yet so available funds should be all zeroes
+	av, err := mgr.AvailableFunds(from, to)
+	require.NoError(t, err)
+	require.Nil(t, av.Channel)
+	require.Nil(t, av.PendingWaitSentinel)
+	require.EqualValues(t, 0, av.ConfirmedAmt.Int64())
+	require.EqualValues(t, 0, av.PendingAmt.Int64())
+	require.EqualValues(t, 0, av.QueuedAmt.Int64())
+	require.EqualValues(t, 0, av.VoucherReedeemedAmt.Int64())
+
+	// Send create message for a channel with value 10
+	createAmt := big.NewInt(10)
+	_, createMsgCid, err := mgr.GetPaych(ctx, from, to, createAmt)
+	require.NoError(t, err)
+
+	// Available funds should reflect create channel message sent
+	av, err = mgr.AvailableFunds(from, to)
+	require.NoError(t, err)
+	require.Nil(t, av.Channel)
+	require.EqualValues(t, 0, av.ConfirmedAmt.Int64())
+	require.EqualValues(t, createAmt, av.PendingAmt)
+	require.EqualValues(t, 0, av.QueuedAmt.Int64())
+	require.EqualValues(t, 0, av.VoucherReedeemedAmt.Int64())
+	// Should now have a pending wait sentinel
+	require.NotNil(t, av.PendingWaitSentinel)
+
+	// Queue up an add funds request behind create channel
+	var addFundsSent sync.WaitGroup
+	addFundsSent.Add(1)
+
+	addFundsAmt := big.NewInt(5)
+	var addFundsMcid cid.Cid
+	go func() {
+		defer addFundsSent.Done()
+
+		// Request add funds - should block until create channel has completed
+		_, addFundsMcid, err = mgr.GetPaych(ctx, from, to, addFundsAmt)
+		require.NoError(t, err)
+	}()
+
+	// Wait for add funds request to be queued up
+	waitForQueueSize(t, mgr, from, to, 1)
+
+	// Available funds should now include queued funds
+	av, err = mgr.AvailableFunds(from, to)
+	require.NoError(t, err)
+	require.Nil(t, av.Channel)
+	require.NotNil(t, av.PendingWaitSentinel)
+	require.EqualValues(t, 0, av.ConfirmedAmt.Int64())
+	// create amount is still pending
+	require.EqualValues(t, createAmt, av.PendingAmt)
+	// queued amount now includes add funds amount
+	require.EqualValues(t, addFundsAmt, av.QueuedAmt)
+	require.EqualValues(t, 0, av.VoucherReedeemedAmt.Int64())
+
+	// Create channel in state
+	arr, err := adt.MakeEmptyArray(mock.store).Root()
+	require.NoError(t, err)
+	mock.setAccountState(fromAcct, account.State{Address: from})
+	mock.setAccountState(toAcct, account.State{Address: to})
+	act := &types.Actor{
+		Code:    builtin.AccountActorCodeID,
+		Head:    cid.Cid{},
+		Nonce:   0,
+		Balance: createAmt,
+	}
+	mock.setPaychState(ch, act, paych.State{
+		From:            fromAcct,
+		To:              toAcct,
+		ToSend:          big.NewInt(0),
+		SettlingAt:      abi.ChainEpoch(0),
+		MinSettleHeight: abi.ChainEpoch(0),
+		LaneStates:      arr,
+	})
+
+	// Send create channel response
+	response := testChannelResponse(t, ch)
+	mock.receiveMsgResponse(createMsgCid, response)
+
+	// Wait for create channel response
+	chres, err := mgr.GetPaychWaitReady(ctx, *av.PendingWaitSentinel)
+	require.NoError(t, err)
+	require.Equal(t, ch, chres)
+
+	// Wait for add funds request to be sent
+	addFundsSent.Wait()
+
+	// Available funds should now include the channel and also a wait sentinel
+	// for the add funds message
+	av, err = mgr.AvailableFunds(from, to)
+	require.NoError(t, err)
+	require.NotNil(t, av.Channel)
+	require.NotNil(t, av.PendingWaitSentinel)
+	// create amount is now confirmed
+	require.EqualValues(t, createAmt, av.ConfirmedAmt)
+	// add funds amount it now pending
+	require.EqualValues(t, addFundsAmt, av.PendingAmt)
+	require.EqualValues(t, 0, av.QueuedAmt.Int64())
+	require.EqualValues(t, 0, av.VoucherReedeemedAmt.Int64())
+
+	// Send success add funds response
+	mock.receiveMsgResponse(addFundsMcid, types.MessageReceipt{
+		ExitCode: 0,
+		Return:   []byte{},
+	})
+
+	// Wait for add funds response
+	_, err = mgr.GetPaychWaitReady(ctx, *av.PendingWaitSentinel)
+	require.NoError(t, err)
+
+	// Available funds should no longer have a wait sentinel
+	av, err = mgr.AvailableFunds(from, to)
+	require.NoError(t, err)
+	require.NotNil(t, av.Channel)
+	require.Nil(t, av.PendingWaitSentinel)
+	// confirmed amount now includes create and add funds amounts
+	require.EqualValues(t, types.BigAdd(createAmt, addFundsAmt), av.ConfirmedAmt)
+	require.EqualValues(t, 0, av.PendingAmt.Int64())
+	require.EqualValues(t, 0, av.QueuedAmt.Int64())
+	require.EqualValues(t, 0, av.VoucherReedeemedAmt.Int64())
+
+	// Add some vouchers
+	voucherAmt1 := types.NewInt(3)
+	voucher := createTestVoucher(t, ch, 1, 1, voucherAmt1, fromKeyPrivate)
+	_, err = mgr.AddVoucherOutbound(ctx, ch, voucher, nil, types.NewInt(0))
+	require.NoError(t, err)
+
+	voucherAmt2 := types.NewInt(2)
+	voucher = createTestVoucher(t, ch, 2, 1, voucherAmt2, fromKeyPrivate)
+	_, err = mgr.AddVoucherOutbound(ctx, ch, voucher, nil, types.NewInt(0))
+	require.NoError(t, err)
+
+	av, err = mgr.AvailableFunds(from, to)
+	require.NoError(t, err)
+	require.NotNil(t, av.Channel)
+	require.Nil(t, av.PendingWaitSentinel)
+	require.EqualValues(t, types.BigAdd(createAmt, addFundsAmt), av.ConfirmedAmt)
+	require.EqualValues(t, 0, av.PendingAmt.Int64())
+	require.EqualValues(t, 0, av.QueuedAmt.Int64())
+	// voucher redeemed amount now includes vouchers
+	require.EqualValues(t, types.BigAdd(voucherAmt1, voucherAmt2), av.VoucherReedeemedAmt)
+}
+
 // waitForQueueSize waits for the funds request queue to be of the given size
 func waitForQueueSize(t *testing.T, mgr *Manager, from address.Address, to address.Address, size int) {
 	ca, err := mgr.accessorByFromTo(from, to)

paychmgr/simple.go

@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"sync"
 
+	"github.com/filecoin-project/lotus/api"
+
 	"golang.org/x/sync/errgroup"
 
 	"github.com/filecoin-project/specs-actors/actors/abi/big"
@@ -191,17 +193,17 @@ func (ca *channelAccessor) getPaych(ctx context.Context, from, to address.Addres
 	}
 }
 
-// Queue up an add funds operations
+// Queue up an add funds operation
 func (ca *channelAccessor) enqueue(task *fundsReq) {
 	ca.lk.Lock()
 	defer ca.lk.Unlock()
 
 	ca.fundsReqQueue = append(ca.fundsReqQueue, task)
-	go ca.processQueue()
+	go ca.processQueue() // nolint: errcheck
 }
 
 // Run the operations in the queue
-func (ca *channelAccessor) processQueue() {
+func (ca *channelAccessor) processQueue() (*api.ChannelAvailableFunds, error) {
 	ca.lk.Lock()
 	defer ca.lk.Unlock()
 
@@ -210,7 +212,7 @@ func (ca *channelAccessor) processQueue() {
 
 	// If there's nothing in the queue, bail out
 	if len(ca.fundsReqQueue) == 0 {
-		return
+		return ca.currentAvailableFunds(types.NewInt(0))
 	}
 
 	// Merge all pending requests into one.
@@ -221,7 +223,7 @@ func (ca *channelAccessor) processQueue() {
 	if amt.IsZero() {
 		// Note: The amount can be zero if requests are cancelled as we're
 		// building the mergedFundsReq
-		return
+		return ca.currentAvailableFunds(amt)
 	}
 
 	res := ca.processTask(merged.ctx, merged.from(), merged.to(), amt)
@@ -231,7 +233,7 @@ func (ca *channelAccessor) processQueue() {
 	if res == nil {
 		// Stop processing the fundsReqQueue and wait. When the event occurs it will
 		// call processQueue() again
-		return
+		return ca.currentAvailableFunds(amt)
 	}
 
 	// Finished processing so clear the queue
@@ -239,6 +241,8 @@ func (ca *channelAccessor) processQueue() {
 
 	// Call the task callback with its results
 	merged.onComplete(res)
+
+	return ca.currentAvailableFunds(types.NewInt(0))
 }
 
 // filterQueue filters cancelled requests out of the queue
@@ -291,10 +295,65 @@ func (ca *channelAccessor) msgWaitComplete(mcid cid.Cid, err error) {
 	// The queue may have been waiting for msg completion to proceed, so
 	// process the next queue item
 	if len(ca.fundsReqQueue) > 0 {
-		go ca.processQueue()
+		go ca.processQueue() // nolint: errcheck
 	}
 }
 
+func (ca *channelAccessor) currentAvailableFunds(queuedAmt types.BigInt) (*api.ChannelAvailableFunds, error) {
+	channelInfo, err := ca.store.OutboundActiveByFromTo(ca.from, ca.to)
+	if err != nil && err != ErrChannelNotTracked {
+		return nil, err
+	}
+
+	if channelInfo == nil {
+		// Channel does not exist
+		return &api.ChannelAvailableFunds{
+			Channel:             nil,
+			ConfirmedAmt:        types.NewInt(0),
+			PendingAmt:          types.NewInt(0),
+			PendingWaitSentinel: nil,
+			QueuedAmt:           queuedAmt,
+			VoucherReedeemedAmt: types.NewInt(0),
+		}, nil
+	}
+
+	// The channel may have a pending create or add funds message
+	waitSentinel := channelInfo.CreateMsg
+	if waitSentinel == nil {
+		waitSentinel = channelInfo.AddFundsMsg
+	}
+
+	// Get the total amount redeemed by vouchers.
+	// This includes vouchers that have been submitted, and vouchers that are
+	// in the datastore but haven't yet been submitted.
+	totalRedeemed := types.NewInt(0)
+	if channelInfo.Channel != nil {
+		ch := *channelInfo.Channel
+		_, pchState, err := ca.sa.loadPaychActorState(ca.chctx, ch)
+		if err != nil {
+			return nil, err
+		}
+
+		laneStates, err := ca.laneState(ca.chctx, pchState, ch)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, ls := range laneStates {
+			totalRedeemed = types.BigAdd(totalRedeemed, ls.Redeemed)
+		}
+	}
+
+	return &api.ChannelAvailableFunds{
+		Channel:             channelInfo.Channel,
+		ConfirmedAmt:        channelInfo.Amount,
+		PendingAmt:          channelInfo.PendingAmount,
+		PendingWaitSentinel: waitSentinel,
+		QueuedAmt:           queuedAmt,
+		VoucherReedeemedAmt: totalRedeemed,
+	}, nil
+}
+
 // processTask checks the state of the channel and takes appropriate action
 // (see description of getPaych).
 // Note that processTask may be called repeatedly in the same state, and should
@@ -397,7 +456,7 @@ func (ca *channelAccessor) waitForPaychCreateMsg(channelID string, mcid cid.Cid)
 }
 
 func (ca *channelAccessor) waitPaychCreateMsg(channelID string, mcid cid.Cid) error {
-	mwait, err := ca.api.StateWaitMsg(ca.waitCtx, mcid, build.MessageConfidence)
+	mwait, err := ca.api.StateWaitMsg(ca.chctx, mcid, build.MessageConfidence)
 	if err != nil {
 		log.Errorf("wait msg: %w", err)
 		return err
@@ -480,7 +539,7 @@ func (ca *channelAccessor) waitForAddFundsMsg(channelID string, mcid cid.Cid) {
 }
 
 func (ca *channelAccessor) waitAddFundsMsg(channelID string, mcid cid.Cid) error {
-	mwait, err := ca.api.StateWaitMsg(ca.waitCtx, mcid, build.MessageConfidence)
+	mwait, err := ca.api.StateWaitMsg(ca.chctx, mcid, build.MessageConfidence)
 	if err != nil {
 		log.Error(err)
 		return err
@@ -669,3 +728,7 @@ func (ca *channelAccessor) msgPromise(ctx context.Context, mcid cid.Cid) chan on
 
 	return promise
 }
+
+func (ca *channelAccessor) availableFunds() (*api.ChannelAvailableFunds, error) {
+	return ca.processQueue()
+}