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package rpc
import (
"bytes"
"context"
"errors"
"fmt"
"time"
"github.com/gogo/protobuf/proto"
abci "github.com/tendermint/tendermint/abci/types"
"github.com/tendermint/tendermint/crypto/merkle"
tmbytes "github.com/tendermint/tendermint/libs/bytes"
tmmath "github.com/tendermint/tendermint/libs/math"
service "github.com/tendermint/tendermint/libs/service"
rpcclient "github.com/tendermint/tendermint/rpc/client"
ctypes "github.com/tendermint/tendermint/rpc/core/types"
rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
"github.com/tendermint/tendermint/types"
)
var errNegOrZeroHeight = errors.New("negative or zero height")
// KeyPathFunc builds a merkle path out of the given path and key.
type KeyPathFunc func(path string, key []byte) (merkle.KeyPath, error)
// LightClient is an interface that contains functionality needed by Client from the light client.
type LightClient interface {
ChainID() string
VerifyLightBlockAtHeight(ctx context.Context, height int64, now time.Time) (*types.LightBlock, error)
TrustedLightBlock(height int64) (*types.LightBlock, error)
}
// Client is an RPC client, which uses light#Client to verify data (if it can
// be proved!). merkle.DefaultProofRuntime is used to verify values returned by
// ABCIQuery.
type Client struct {
service.BaseService
next rpcclient.Client
lc LightClient
// Proof runtime used to verify values returned by ABCIQuery
prt *merkle.ProofRuntime
keyPathFn KeyPathFunc
}
var _ rpcclient.Client = (*Client)(nil)
// Option allow you to tweak Client.
type Option func(*Client)
// KeyPathFn option can be used to set a function, which parses a given path
// and builds the merkle path for the prover. It must be provided if you want
// to call ABCIQuery or ABCIQueryWithOptions.
func KeyPathFn(fn KeyPathFunc) Option {
return func(c *Client) {
c.keyPathFn = fn
}
}
// NewClient returns a new client.
func NewClient(next rpcclient.Client, lc LightClient, opts ...Option) *Client {
c := &Client{
next: next,
lc: lc,
prt: merkle.DefaultProofRuntime(),
}
c.BaseService = *service.NewBaseService(nil, "Client", c)
for _, o := range opts {
o(c)
}
return c
}
func (c *Client) OnStart() error {
if !c.next.IsRunning() {
return c.next.Start()
}
return nil
}
func (c *Client) OnStop() {
if c.next.IsRunning() {
if err := c.next.Stop(); err != nil {
c.Logger.Error("Error stopping on next", "err", err)
}
}
}
func (c *Client) Status(ctx context.Context) (*ctypes.ResultStatus, error) {
return c.next.Status(ctx)
}
func (c *Client) ABCIInfo(ctx context.Context) (*ctypes.ResultABCIInfo, error) {
return c.next.ABCIInfo(ctx)
}
// ABCIQuery requests proof by default.
func (c *Client) ABCIQuery(ctx context.Context, path string, data tmbytes.HexBytes) (*ctypes.ResultABCIQuery, error) {
return c.ABCIQueryWithOptions(ctx, path, data, rpcclient.DefaultABCIQueryOptions)
}
// ABCIQueryWithOptions returns an error if opts.Prove is false.
func (c *Client) ABCIQueryWithOptions(ctx context.Context, path string, data tmbytes.HexBytes,
opts rpcclient.ABCIQueryOptions) (*ctypes.ResultABCIQuery, error) {
// always request the proof
opts.Prove = true
res, err := c.next.ABCIQueryWithOptions(ctx, path, data, opts)
if err != nil {
return nil, err
}
resp := res.Response
// Validate the response.
if resp.IsErr() {
return nil, fmt.Errorf("err response code: %v", resp.Code)
}
if len(resp.Key) == 0 {
return nil, errors.New("empty key")
}
if resp.ProofOps == nil || len(resp.ProofOps.Ops) == 0 {
return nil, errors.New("no proof ops")
}
if resp.Height <= 0 {
return nil, errNegOrZeroHeight
}
// Update the light client if we're behind.
// NOTE: AppHash for height H is in header H+1.
l, err := c.updateLightClientIfNeededTo(ctx, resp.Height+1)
if err != nil {
return nil, err
}
// Validate the value proof against the trusted header.
if resp.Value != nil {
// 1) build a Merkle key path from path and resp.Key
if c.keyPathFn == nil {
return nil, errors.New("please configure Client with KeyPathFn option")
}
kp, err := c.keyPathFn(path, resp.Key)
if err != nil {
return nil, fmt.Errorf("can't build merkle key path: %w", err)
}
// 2) verify value
err = c.prt.VerifyValue(resp.ProofOps, l.AppHash, kp.String(), resp.Value)
if err != nil {
return nil, fmt.Errorf("verify value proof: %w", err)
}
} else { // OR validate the absence proof against the trusted header.
err = c.prt.VerifyAbsence(resp.ProofOps, l.AppHash, string(resp.Key))
if err != nil {
return nil, fmt.Errorf("verify absence proof: %w", err)
}
}
return &ctypes.ResultABCIQuery{Response: resp}, nil
}
func (c *Client) BroadcastTxCommit(ctx context.Context, tx types.Tx) (*ctypes.ResultBroadcastTxCommit, error) {
return c.next.BroadcastTxCommit(ctx, tx)
}
func (c *Client) BroadcastTxAsync(ctx context.Context, tx types.Tx) (*ctypes.ResultBroadcastTx, error) {
return c.next.BroadcastTxAsync(ctx, tx)
}
func (c *Client) BroadcastTxSync(ctx context.Context, tx types.Tx) (*ctypes.ResultBroadcastTx, error) {
return c.next.BroadcastTxSync(ctx, tx)
}
func (c *Client) UnconfirmedTxs(ctx context.Context, limit *int) (*ctypes.ResultUnconfirmedTxs, error) {
return c.next.UnconfirmedTxs(ctx, limit)
}
func (c *Client) NumUnconfirmedTxs(ctx context.Context) (*ctypes.ResultUnconfirmedTxs, error) {
return c.next.NumUnconfirmedTxs(ctx)
}
func (c *Client) CheckTx(ctx context.Context, tx types.Tx) (*ctypes.ResultCheckTx, error) {
return c.next.CheckTx(ctx, tx)
}
func (c *Client) NetInfo(ctx context.Context) (*ctypes.ResultNetInfo, error) {
return c.next.NetInfo(ctx)
}
func (c *Client) DumpConsensusState(ctx context.Context) (*ctypes.ResultDumpConsensusState, error) {
return c.next.DumpConsensusState(ctx)
}
func (c *Client) ConsensusState(ctx context.Context) (*ctypes.ResultConsensusState, error) {
return c.next.ConsensusState(ctx)
}
func (c *Client) ConsensusParams(ctx context.Context, height *int64) (*ctypes.ResultConsensusParams, error) {
res, err := c.next.ConsensusParams(ctx, height)
if err != nil {
return nil, err
}
// Validate res.
if err := types.ValidateConsensusParams(res.ConsensusParams); err != nil {
return nil, err
}
if res.BlockHeight <= 0 {
return nil, errNegOrZeroHeight
}
// Update the light client if we're behind.
l, err := c.updateLightClientIfNeededTo(ctx, res.BlockHeight)
if err != nil {
return nil, err
}
// Verify hash.
if cH, tH := types.HashConsensusParams(res.ConsensusParams), l.ConsensusHash; !bytes.Equal(cH, tH) {
return nil, fmt.Errorf("params hash %X does not match trusted hash %X",
cH, tH)
}
return res, nil
}
func (c *Client) Health(ctx context.Context) (*ctypes.ResultHealth, error) {
return c.next.Health(ctx)
}
// BlockchainInfo calls rpcclient#BlockchainInfo and then verifies every header
// returned.
func (c *Client) BlockchainInfo(ctx context.Context, minHeight, maxHeight int64) (*ctypes.ResultBlockchainInfo, error) {
res, err := c.next.BlockchainInfo(ctx, minHeight, maxHeight)
if err != nil {
return nil, err
}
// Validate res.
for i, meta := range res.BlockMetas {
if meta == nil {
return nil, fmt.Errorf("nil block meta %d", i)
}
if err := meta.ValidateBasic(); err != nil {
return nil, fmt.Errorf("invalid block meta %d: %w", i, err)
}
}
// Update the light client if we're behind.
if len(res.BlockMetas) > 0 {
lastHeight := res.BlockMetas[len(res.BlockMetas)-1].Header.Height
if _, err := c.updateLightClientIfNeededTo(ctx, lastHeight); err != nil {
return nil, err
}
}
// Verify each of the BlockMetas.
for _, meta := range res.BlockMetas {
h, err := c.lc.TrustedLightBlock(meta.Header.Height)
if err != nil {
return nil, fmt.Errorf("trusted header %d: %w", meta.Header.Height, err)
}
if bmH, tH := meta.Header.Hash(), h.Hash(); !bytes.Equal(bmH, tH) {
return nil, fmt.Errorf("block meta header %X does not match with trusted header %X",
bmH, tH)
}
}
return res, nil
}
func (c *Client) Genesis(ctx context.Context) (*ctypes.ResultGenesis, error) {
return c.next.Genesis(ctx)
}
// Block calls rpcclient#Block and then verifies the result.
func (c *Client) Block(ctx context.Context, height *int64) (*ctypes.ResultBlock, error) {
res, err := c.next.Block(ctx, height)
if err != nil {
return nil, err
}
// Validate res.
if err := res.BlockID.ValidateBasic(); err != nil {
return nil, err
}
if err := res.Block.ValidateBasic(); err != nil {
return nil, err
}
if bmH, bH := res.BlockID.Hash, res.Block.Hash(); !bytes.Equal(bmH, bH) {
return nil, fmt.Errorf("blockID %X does not match with block %X",
bmH, bH)
}
// Update the light client if we're behind.
l, err := c.updateLightClientIfNeededTo(ctx, res.Block.Height)
if err != nil {
return nil, err
}
// Verify block.
if bH, tH := res.Block.Hash(), l.Hash(); !bytes.Equal(bH, tH) {
return nil, fmt.Errorf("block header %X does not match with trusted header %X",
bH, tH)
}
return res, nil
}
// BlockByHash calls rpcclient#BlockByHash and then verifies the result.
func (c *Client) BlockByHash(ctx context.Context, hash []byte) (*ctypes.ResultBlock, error) {
res, err := c.next.BlockByHash(ctx, hash)
if err != nil {
return nil, err
}
// Validate res.
if err := res.BlockID.ValidateBasic(); err != nil {
return nil, err
}
if err := res.Block.ValidateBasic(); err != nil {
return nil, err
}
if bmH, bH := res.BlockID.Hash, res.Block.Hash(); !bytes.Equal(bmH, bH) {
return nil, fmt.Errorf("blockID %X does not match with block %X",
bmH, bH)
}
// Update the light client if we're behind.
l, err := c.updateLightClientIfNeededTo(ctx, res.Block.Height)
if err != nil {
return nil, err
}
// Verify block.
if bH, tH := res.Block.Hash(), l.Hash(); !bytes.Equal(bH, tH) {
return nil, fmt.Errorf("block header %X does not match with trusted header %X",
bH, tH)
}
return res, nil
}
// BlockResults returns the block results for the given height. If no height is
// provided, the results of the block preceding the latest are returned.
func (c *Client) BlockResults(ctx context.Context, height *int64) (*ctypes.ResultBlockResults, error) {
var h int64
if height == nil {
res, err := c.next.Status(ctx)
if err != nil {
return nil, fmt.Errorf("can't get latest height: %w", err)
}
// Can't return the latest block results here because we won't be able to
// prove them. Return the results for the previous block instead.
h = res.SyncInfo.LatestBlockHeight - 1
} else {
h = *height
}
res, err := c.next.BlockResults(ctx, &h)
if err != nil {
return nil, err
}
// Validate res.
if res.Height <= 0 {
return nil, errNegOrZeroHeight
}
// Update the light client if we're behind.
trustedBlock, err := c.updateLightClientIfNeededTo(ctx, h+1)
if err != nil {
return nil, err
}
// proto-encode BeginBlock events
bbeBytes, err := proto.Marshal(&abci.ResponseBeginBlock{
Events: res.BeginBlockEvents,
})
if err != nil {
return nil, err
}
// Build a Merkle tree of proto-encoded DeliverTx results and get a hash.
results := types.NewResults(res.TxsResults)
// proto-encode EndBlock events.
ebeBytes, err := proto.Marshal(&abci.ResponseEndBlock{
Events: res.EndBlockEvents,
})
if err != nil {
return nil, err
}
// Build a Merkle tree out of the above 3 binary slices.
rH := merkle.HashFromByteSlices([][]byte{bbeBytes, results.Hash(), ebeBytes})
// Verify block results.
if !bytes.Equal(rH, trustedBlock.LastResultsHash) {
return nil, fmt.Errorf("last results %X does not match with trusted last results %X",
rH, trustedBlock.LastResultsHash)
}
return res, nil
}
func (c *Client) Commit(ctx context.Context, height *int64) (*ctypes.ResultCommit, error) {
// Update the light client if we're behind and retrieve the light block at the requested height
l, err := c.updateLightClientIfNeededTo(ctx, *height)
if err != nil {
return nil, err
}
return &ctypes.ResultCommit{
SignedHeader: *l.SignedHeader,
CanonicalCommit: true,
}, nil
}
// Tx calls rpcclient#Tx method and then verifies the proof if such was
// requested.
func (c *Client) Tx(ctx context.Context, hash []byte, prove bool) (*ctypes.ResultTx, error) {
res, err := c.next.Tx(ctx, hash, prove)
if err != nil || !prove {
return res, err
}
// Validate res.
if res.Height <= 0 {
return nil, errNegOrZeroHeight
}
// Update the light client if we're behind.
l, err := c.updateLightClientIfNeededTo(ctx, res.Height)
if err != nil {
return nil, err
}
// Validate the proof.
return res, res.Proof.Validate(l.DataHash)
}
func (c *Client) TxSearch(ctx context.Context, query string, prove bool, page, perPage *int, orderBy string) (
*ctypes.ResultTxSearch, error) {
return c.next.TxSearch(ctx, query, prove, page, perPage, orderBy)
}
// Validators fetches and verifies validators.
func (c *Client) Validators(ctx context.Context, height *int64, pagePtr, perPagePtr *int) (*ctypes.ResultValidators,
error) {
// Update the light client if we're behind and retrieve the light block at the requested height.
l, err := c.updateLightClientIfNeededTo(ctx, *height)
if err != nil {
return nil, err
}
totalCount := len(l.ValidatorSet.Validators)
perPage := validatePerPage(perPagePtr)
page, err := validatePage(pagePtr, perPage, totalCount)
if err != nil {
return nil, err
}
skipCount := validateSkipCount(page, perPage)
v := l.ValidatorSet.Validators[skipCount : skipCount+tmmath.MinInt(perPage, totalCount-skipCount)]
return &ctypes.ResultValidators{
BlockHeight: *height,
Validators: v,
Count: len(v),
Total: totalCount}, nil
}
func (c *Client) BroadcastEvidence(ctx context.Context, ev types.Evidence) (*ctypes.ResultBroadcastEvidence, error) {
return c.next.BroadcastEvidence(ctx, ev)
}
func (c *Client) Subscribe(ctx context.Context, subscriber, query string,
outCapacity ...int) (out <-chan ctypes.ResultEvent, err error) {
return c.next.Subscribe(ctx, subscriber, query, outCapacity...)
}
func (c *Client) Unsubscribe(ctx context.Context, subscriber, query string) error {
return c.next.Unsubscribe(ctx, subscriber, query)
}
func (c *Client) UnsubscribeAll(ctx context.Context, subscriber string) error {
return c.next.UnsubscribeAll(ctx, subscriber)
}
func (c *Client) updateLightClientIfNeededTo(ctx context.Context, height int64) (*types.LightBlock, error) {
l, err := c.lc.VerifyLightBlockAtHeight(ctx, height, time.Now())
if err != nil {
return nil, fmt.Errorf("failed to update light client to %d: %w", height, err)
}
return l, nil
}
func (c *Client) RegisterOpDecoder(typ string, dec merkle.OpDecoder) {
c.prt.RegisterOpDecoder(typ, dec)
}
// SubscribeWS subscribes for events using the given query and remote address as
// a subscriber, but does not verify responses (UNSAFE)!
// TODO: verify data
func (c *Client) SubscribeWS(ctx *rpctypes.Context, query string) (*ctypes.ResultSubscribe, error) {
out, err := c.next.Subscribe(context.Background(), ctx.RemoteAddr(), query)
if err != nil {
return nil, err
}
go func() {
for {
select {
case resultEvent := <-out:
// We should have a switch here that performs a validation
// depending on the event's type.
ctx.WSConn.TryWriteRPCResponse(
rpctypes.NewRPCSuccessResponse(
rpctypes.JSONRPCStringID(fmt.Sprintf("%v#event", ctx.JSONReq.ID)),
resultEvent,
))
case <-c.Quit():
return
}
}
}()
return &ctypes.ResultSubscribe{}, nil
}
// UnsubscribeWS calls original client's Unsubscribe using remote address as a
// subscriber.
func (c *Client) UnsubscribeWS(ctx *rpctypes.Context, query string) (*ctypes.ResultUnsubscribe, error) {
err := c.next.Unsubscribe(context.Background(), ctx.RemoteAddr(), query)
if err != nil {
return nil, err
}
return &ctypes.ResultUnsubscribe{}, nil
}
// UnsubscribeAllWS calls original client's UnsubscribeAll using remote address
// as a subscriber.
func (c *Client) UnsubscribeAllWS(ctx *rpctypes.Context) (*ctypes.ResultUnsubscribe, error) {
err := c.next.UnsubscribeAll(context.Background(), ctx.RemoteAddr())
if err != nil {
return nil, err
}
return &ctypes.ResultUnsubscribe{}, nil
}
// XXX: Copied from rpc/core/env.go
const (
// see README
defaultPerPage = 30
maxPerPage = 100
)
func validatePage(pagePtr *int, perPage, totalCount int) (int, error) {
if perPage < 1 {
panic(fmt.Sprintf("zero or negative perPage: %d", perPage))
}
if pagePtr == nil { // no page parameter
return 1, nil
}
pages := ((totalCount - 1) / perPage) + 1
if pages == 0 {
pages = 1 // one page (even if it's empty)
}
page := *pagePtr
if page <= 0 || page > pages {
return 1, fmt.Errorf("page should be within [1, %d] range, given %d", pages, page)
}
return page, nil
}
func validatePerPage(perPagePtr *int) int {
if perPagePtr == nil { // no per_page parameter
return defaultPerPage
}
perPage := *perPagePtr
if perPage < 1 {
return defaultPerPage
} else if perPage > maxPerPage {
return maxPerPage
}
return perPage
}
func validateSkipCount(page, perPage int) int {
skipCount := (page - 1) * perPage
if skipCount < 0 {
return 0
}
return skipCount
}