lotus/paychmgr/paych.go
2020-08-12 22:17:29 +02:00

443 lines
11 KiB
Go

package paychmgr
import (
"bytes"
"context"
"fmt"
"github.com/ipfs/go-cid"
"github.com/filecoin-project/go-address"
cborutil "github.com/filecoin-project/go-cbor-util"
"github.com/filecoin-project/lotus/chain/actors"
"github.com/filecoin-project/lotus/chain/types"
"github.com/filecoin-project/lotus/lib/sigs"
"github.com/filecoin-project/specs-actors/actors/abi/big"
"github.com/filecoin-project/specs-actors/actors/builtin"
"github.com/filecoin-project/specs-actors/actors/builtin/account"
"github.com/filecoin-project/specs-actors/actors/builtin/paych"
xerrors "golang.org/x/xerrors"
)
// 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
// on chain
waitCtx context.Context
sa *stateAccessor
api managerAPI
store *Store
lk *channelLock
fundsReqQueue []*fundsReq
msgListeners msgListeners
}
func newChannelAccessor(pm *Manager) *channelAccessor {
return &channelAccessor{
lk: &channelLock{globalLock: &pm.lk},
sa: pm.sa,
api: pm.pchapi,
store: pm.store,
msgListeners: newMsgListeners(),
waitCtx: pm.ctx,
}
}
func (ca *channelAccessor) getChannelInfo(addr address.Address) (*ChannelInfo, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
return ca.store.ByAddress(addr)
}
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()
return ca.checkVoucherValidUnlocked(ctx, ch, sv)
}
func (ca *channelAccessor) checkVoucherValidUnlocked(ctx context.Context, ch address.Address, sv *paych.SignedVoucher) (map[uint64]*paych.LaneState, error) {
if sv.ChannelAddr != ch {
return nil, xerrors.Errorf("voucher ChannelAddr doesn't match channel address, got %s, expected %s", sv.ChannelAddr, ch)
}
act, pchState, err := ca.sa.loadPaychState(ctx, ch)
if err != nil {
return nil, err
}
var actState account.State
_, err = ca.api.LoadActorState(ctx, pchState.From, &actState, nil)
if err != nil {
return nil, err
}
from := actState.Address
// verify signature
vb, err := sv.SigningBytes()
if err != nil {
return nil, err
}
// TODO: technically, either party may create and sign a voucher.
// However, for now, we only accept them from the channel creator.
// More complex handling logic can be added later
if err := sigs.Verify(sv.Signature, from, vb); err != nil {
return nil, err
}
// Check the voucher against the highest known voucher nonce / value
laneStates, err := ca.laneState(pchState, ch)
if err != nil {
return nil, err
}
// If the new voucher nonce value is less than the highest known
// nonce for the lane
ls, lsExists := laneStates[sv.Lane]
if lsExists && sv.Nonce <= ls.Nonce {
return nil, fmt.Errorf("nonce too low")
}
// If the voucher amount is less than the highest known voucher amount
if lsExists && sv.Amount.LessThanEqual(ls.Redeemed) {
return nil, fmt.Errorf("voucher amount is lower than amount for voucher with lower nonce")
}
// Total redeemed is the total redeemed amount for all lanes, including
// the new voucher
// eg
//
// lane 1 redeemed: 3
// lane 2 redeemed: 2
// voucher for lane 1: 5
//
// Voucher supersedes lane 1 redeemed, therefore
// effective lane 1 redeemed: 5
//
// lane 1: 5
// lane 2: 2
// -
// total: 7
totalRedeemed, err := ca.totalRedeemedWithVoucher(laneStates, sv)
if err != nil {
return nil, err
}
// Total required balance = total redeemed + toSend
// 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")
}
if len(sv.Merges) != 0 {
return nil, fmt.Errorf("dont currently support paych lane merges")
}
return laneStates, nil
}
func (ca *channelAccessor) checkVoucherSpendable(ctx context.Context, ch address.Address, sv *paych.SignedVoucher, secret []byte, proof []byte) (bool, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
recipient, err := ca.getPaychRecipient(ctx, ch)
if err != nil {
return false, err
}
if sv.Extra != nil && proof == nil {
known, err := ca.store.VouchersForPaych(ch)
if err != nil {
return false, err
}
for _, v := range known {
eq, err := cborutil.Equals(v.Voucher, sv)
if err != nil {
return false, err
}
if v.Proof != nil && eq {
log.Info("CheckVoucherSpendable: using stored proof")
proof = v.Proof
break
}
}
if proof == nil {
log.Warn("CheckVoucherSpendable: nil proof for voucher with validation")
}
}
enc, err := actors.SerializeParams(&paych.UpdateChannelStateParams{
Sv: *sv,
Secret: secret,
Proof: proof,
})
if err != nil {
return false, err
}
ret, err := ca.api.Call(ctx, &types.Message{
From: recipient,
To: ch,
Method: builtin.MethodsPaych.UpdateChannelState,
Params: enc,
}, nil)
if err != nil {
return false, err
}
if ret.MsgRct.ExitCode != 0 {
return false, nil
}
return true, nil
}
func (ca *channelAccessor) getPaychRecipient(ctx context.Context, ch address.Address) (address.Address, error) {
var state paych.State
if _, err := ca.api.LoadActorState(ctx, ch, &state, nil); err != nil {
return address.Address{}, err
}
return state.To, nil
}
func (ca *channelAccessor) addVoucher(ctx context.Context, ch address.Address, sv *paych.SignedVoucher, proof []byte, minDelta types.BigInt) (types.BigInt, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
ci, err := ca.store.ByAddress(ch)
if err != nil {
return types.BigInt{}, err
}
// Check if the voucher has already been added
for i, v := range ci.Vouchers {
eq, err := cborutil.Equals(sv, v.Voucher)
if err != nil {
return types.BigInt{}, err
}
if !eq {
continue
}
// This is a duplicate voucher.
// Update the proof on the existing voucher
if len(proof) > 0 && !bytes.Equal(v.Proof, proof) {
log.Warnf("AddVoucher: adding proof to stored voucher")
ci.Vouchers[i] = &VoucherInfo{
Voucher: v.Voucher,
Proof: proof,
}
return types.NewInt(0), ca.store.putChannelInfo(ci)
}
// Otherwise just ignore the duplicate voucher
log.Warnf("AddVoucher: voucher re-added with matching proof")
return types.NewInt(0), nil
}
// Check voucher validity
laneStates, err := ca.checkVoucherValidUnlocked(ctx, ch, sv)
if err != nil {
return types.NewInt(0), err
}
// The change in value is the delta between the voucher amount and
// the highest previous voucher amount for the lane
laneState, exists := laneStates[sv.Lane]
redeemed := big.NewInt(0)
if exists {
redeemed = laneState.Redeemed
}
delta := types.BigSub(sv.Amount, redeemed)
if minDelta.GreaterThan(delta) {
return delta, xerrors.Errorf("addVoucher: supplied token amount too low; minD=%s, D=%s; laneAmt=%s; v.Amt=%s", minDelta, delta, redeemed, sv.Amount)
}
ci.Vouchers = append(ci.Vouchers, &VoucherInfo{
Voucher: sv,
Proof: proof,
})
if ci.NextLane <= sv.Lane {
ci.NextLane = sv.Lane + 1
}
return delta, ca.store.putChannelInfo(ci)
}
func (ca *channelAccessor) allocateLane(ch address.Address) (uint64, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
// TODO: should this take into account lane state?
return ca.store.AllocateLane(ch)
}
func (ca *channelAccessor) listVouchers(ctx context.Context, ch address.Address) ([]*VoucherInfo, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
// TODO: just having a passthrough method like this feels odd. Seems like
// there should be some filtering we're doing here
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(state *paych.State, ch address.Address) (map[uint64]*paych.LaneState, error) {
// TODO: we probably want to call UpdateChannelState with all vouchers to be fully correct
// (but technically dont't need to)
laneStates := make(map[uint64]*paych.LaneState, len(state.LaneStates))
// Get the lane state from the chain
for _, laneState := range state.LaneStates {
laneStates[laneState.ID] = laneState
}
// Apply locally stored vouchers
vouchers, err := ca.store.VouchersForPaych(ch)
if err != nil && err != ErrChannelNotTracked {
return nil, err
}
for _, v := range vouchers {
for range v.Voucher.Merges {
return nil, xerrors.Errorf("paych merges not handled yet")
}
// If there's a voucher for a lane that isn't in chain state just
// create it
ls, ok := laneStates[v.Voucher.Lane]
if !ok {
ls = &paych.LaneState{
ID: v.Voucher.Lane,
Redeemed: types.NewInt(0),
Nonce: 0,
}
laneStates[v.Voucher.Lane] = ls
}
if v.Voucher.Nonce < ls.Nonce {
continue
}
ls.Nonce = v.Voucher.Nonce
ls.Redeemed = v.Voucher.Amount
}
return laneStates, nil
}
// Get the total redeemed amount across all lanes, after applying the voucher
func (ca *channelAccessor) totalRedeemedWithVoucher(laneStates map[uint64]*paych.LaneState, sv *paych.SignedVoucher) (big.Int, error) {
// TODO: merges
if len(sv.Merges) != 0 {
return big.Int{}, xerrors.Errorf("dont currently support paych lane merges")
}
total := big.NewInt(0)
for _, ls := range laneStates {
total = big.Add(total, ls.Redeemed)
}
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
if sv.Nonce > lane.Nonce {
// Add the delta between the redeemed amount and the voucher
// amount to the total
delta := big.Sub(sv.Amount, lane.Redeemed)
total = big.Add(total, delta)
}
} else {
// If the voucher is *not* for an existing lane, just add its
// value (implicitly a new lane will be created for the voucher)
total = big.Add(total, sv.Amount)
}
return total, nil
}
func (ca *channelAccessor) settle(ctx context.Context, ch address.Address) (cid.Cid, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
ci, err := ca.store.ByAddress(ch)
if err != nil {
return cid.Undef, err
}
msg := &types.Message{
To: ch,
From: ci.Control,
Value: types.NewInt(0),
Method: builtin.MethodsPaych.Settle,
}
smgs, err := ca.api.MpoolPushMessage(ctx, msg, nil)
if err != nil {
return cid.Undef, err
}
ci.Settling = true
err = ca.store.putChannelInfo(ci)
if err != nil {
log.Errorf("Error marking channel as settled: %s", err)
}
return smgs.Cid(), err
}
func (ca *channelAccessor) collect(ctx context.Context, ch address.Address) (cid.Cid, error) {
ca.lk.Lock()
defer ca.lk.Unlock()
ci, err := ca.store.ByAddress(ch)
if err != nil {
return cid.Undef, err
}
msg := &types.Message{
To: ch,
From: ci.Control,
Value: types.NewInt(0),
Method: builtin.MethodsPaych.Collect,
}
smsg, err := ca.api.MpoolPushMessage(ctx, msg, nil)
if err != nil {
return cid.Undef, err
}
return smsg.Cid(), nil
}