You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
337 lines
10 KiB
337 lines
10 KiB
package http
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"fmt"
|
|
"math/rand"
|
|
"net/url"
|
|
"strings"
|
|
"time"
|
|
|
|
"github.com/tendermint/tendermint/light/provider"
|
|
rpcclient "github.com/tendermint/tendermint/rpc/client"
|
|
rpchttp "github.com/tendermint/tendermint/rpc/client/http"
|
|
ctypes "github.com/tendermint/tendermint/rpc/core/types"
|
|
rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
|
|
"github.com/tendermint/tendermint/types"
|
|
)
|
|
|
|
var defaultOptions = Options{
|
|
MaxRetryAttempts: 5,
|
|
Timeout: 5 * time.Second,
|
|
NoBlockThreshold: 5,
|
|
NoResponseThreshold: 5,
|
|
}
|
|
|
|
// http provider uses an RPC client to obtain the necessary information.
|
|
type http struct {
|
|
chainID string
|
|
client rpcclient.RemoteClient
|
|
|
|
// httt provider heuristics
|
|
|
|
// The provider tracks the amount of times that the
|
|
// client doesn't respond. If this exceeds the threshold
|
|
// then the provider will return an unreliable provider error
|
|
noResponseThreshold uint16
|
|
noResponseCount uint16
|
|
|
|
// The provider tracks the amount of time the client
|
|
// doesn't have a block. If this exceeds the threshold
|
|
// then the provider will return an unreliable provider error
|
|
noBlockThreshold uint16
|
|
noBlockCount uint16
|
|
|
|
// In a single request, the provider attempts multiple times
|
|
// with exponential backoff to reach the client. If this
|
|
// exceeds the maxRetry attempts, this result in a ErrNoResponse
|
|
maxRetryAttempts uint16
|
|
}
|
|
|
|
type Options struct {
|
|
// 0 means no retries
|
|
MaxRetryAttempts uint16
|
|
// 0 means no timeout.
|
|
Timeout time.Duration
|
|
// The amount of requests that a client doesn't have the block
|
|
// for before the provider deems the client unreliable
|
|
NoBlockThreshold uint16
|
|
// The amount of requests that a client doesn't respond to
|
|
// before the provider deems the client unreliable
|
|
NoResponseThreshold uint16
|
|
}
|
|
|
|
// New creates a HTTP provider, which is using the rpchttp.HTTP client under
|
|
// the hood. If no scheme is provided in the remote URL, http will be used by
|
|
// default. The 5s timeout is used for all requests.
|
|
func New(chainID, remote string) (provider.Provider, error) {
|
|
return NewWithOptions(chainID, remote, defaultOptions)
|
|
}
|
|
|
|
// NewWithOptions is an extension to creating a new http provider that allows the addition
|
|
// of a specified timeout and maxRetryAttempts
|
|
func NewWithOptions(chainID, remote string, options Options) (provider.Provider, error) {
|
|
// Ensure URL scheme is set (default HTTP) when not provided.
|
|
if !strings.Contains(remote, "://") {
|
|
remote = "http://" + remote
|
|
}
|
|
|
|
httpClient, err := rpchttp.NewWithTimeout(remote, options.Timeout)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return NewWithClientAndOptions(chainID, httpClient, options), nil
|
|
}
|
|
|
|
func NewWithClient(chainID string, client rpcclient.RemoteClient) provider.Provider {
|
|
return NewWithClientAndOptions(chainID, client, defaultOptions)
|
|
}
|
|
|
|
// NewWithClient allows you to provide a custom client.
|
|
func NewWithClientAndOptions(chainID string, client rpcclient.RemoteClient, options Options) provider.Provider {
|
|
return &http{
|
|
client: client,
|
|
chainID: chainID,
|
|
maxRetryAttempts: options.MaxRetryAttempts,
|
|
noResponseThreshold: options.NoResponseThreshold,
|
|
noBlockThreshold: options.NoBlockThreshold,
|
|
}
|
|
}
|
|
|
|
func (p *http) String() string {
|
|
return fmt.Sprintf("http{%s}", p.client.Remote())
|
|
}
|
|
|
|
// LightBlock fetches a LightBlock at the given height and checks the
|
|
// chainID matches.
|
|
func (p *http) LightBlock(ctx context.Context, height int64) (*types.LightBlock, error) {
|
|
h, err := validateHeight(height)
|
|
if err != nil {
|
|
return nil, provider.ErrBadLightBlock{Reason: err}
|
|
}
|
|
|
|
sh, err := p.signedHeader(ctx, h)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if height != 0 && sh.Height != height {
|
|
return nil, provider.ErrBadLightBlock{
|
|
Reason: fmt.Errorf("height %d responded doesn't match height %d requested", sh.Height, height),
|
|
}
|
|
}
|
|
|
|
if sh.Header == nil {
|
|
return nil, provider.ErrBadLightBlock{
|
|
Reason: errors.New("returned header is nil unexpectedly"),
|
|
}
|
|
}
|
|
|
|
vs, err := p.validatorSet(ctx, &sh.Height)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
lb := &types.LightBlock{
|
|
SignedHeader: sh,
|
|
ValidatorSet: vs,
|
|
}
|
|
|
|
err = lb.ValidateBasic(p.chainID)
|
|
if err != nil {
|
|
return nil, provider.ErrBadLightBlock{Reason: err}
|
|
}
|
|
|
|
return lb, nil
|
|
}
|
|
|
|
// ReportEvidence calls `/broadcast_evidence` endpoint.
|
|
func (p *http) ReportEvidence(ctx context.Context, ev types.Evidence) error {
|
|
_, err := p.client.BroadcastEvidence(ctx, ev)
|
|
return err
|
|
}
|
|
|
|
func (p *http) validatorSet(ctx context.Context, height *int64) (*types.ValidatorSet, error) {
|
|
// Since the malicious node could report a massive number of pages, making us
|
|
// spend a considerable time iterating, we restrict the number of pages here.
|
|
// => 10000 validators max
|
|
const maxPages = 100
|
|
|
|
var (
|
|
perPage = 100
|
|
vals = []*types.Validator{}
|
|
page = 1
|
|
total = -1
|
|
)
|
|
|
|
for len(vals) != total && page <= maxPages {
|
|
// create another for loop to control retries. If p.maxRetryAttempts
|
|
// is negative we will keep repeating.
|
|
attempt := uint16(0)
|
|
for {
|
|
res, err := p.client.Validators(ctx, height, &page, &perPage)
|
|
switch e := err.(type) {
|
|
case nil: // success!! Now we validate the response
|
|
if len(res.Validators) == 0 {
|
|
return nil, provider.ErrBadLightBlock{
|
|
Reason: fmt.Errorf("validator set is empty (height: %d, page: %d, per_page: %d)",
|
|
height, page, perPage),
|
|
}
|
|
}
|
|
if res.Total <= 0 {
|
|
return nil, provider.ErrBadLightBlock{
|
|
Reason: fmt.Errorf("total number of vals is <= 0: %d (height: %d, page: %d, per_page: %d)",
|
|
res.Total, height, page, perPage),
|
|
}
|
|
}
|
|
|
|
case *url.Error:
|
|
if e.Timeout() {
|
|
// if we have exceeded retry attempts then return a no response error
|
|
if attempt == p.maxRetryAttempts {
|
|
return nil, p.noResponse()
|
|
}
|
|
attempt++
|
|
// request timed out: we wait and try again with exponential backoff
|
|
time.Sleep(backoffTimeout(attempt))
|
|
continue
|
|
}
|
|
return nil, provider.ErrBadLightBlock{Reason: e}
|
|
|
|
case *rpctypes.RPCError:
|
|
// process the rpc error and return the corresponding error to the light client
|
|
return nil, p.parseRPCError(e)
|
|
|
|
default:
|
|
// check if the error stems from the context
|
|
if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
|
|
return nil, err
|
|
}
|
|
|
|
// If we don't know the error then by default we return an unreliable provider error and
|
|
// terminate the connection with the peer.
|
|
return nil, provider.ErrUnreliableProvider{Reason: e.Error()}
|
|
}
|
|
|
|
// update the total and increment the page index so we can fetch the
|
|
// next page of validators if need be
|
|
total = res.Total
|
|
vals = append(vals, res.Validators...)
|
|
page++
|
|
break
|
|
}
|
|
}
|
|
|
|
valSet, err := types.ValidatorSetFromExistingValidators(vals)
|
|
if err != nil {
|
|
return nil, provider.ErrBadLightBlock{Reason: err}
|
|
}
|
|
return valSet, nil
|
|
}
|
|
|
|
func (p *http) signedHeader(ctx context.Context, height *int64) (*types.SignedHeader, error) {
|
|
// create a for loop to control retries. If p.maxRetryAttempts
|
|
// is negative we will keep repeating.
|
|
for attempt := uint16(0); attempt != p.maxRetryAttempts+1; attempt++ {
|
|
commit, err := p.client.Commit(ctx, height)
|
|
switch e := err.(type) {
|
|
case nil: // success!!
|
|
return &commit.SignedHeader, nil
|
|
|
|
case *url.Error:
|
|
// check if the request timed out
|
|
if e.Timeout() {
|
|
// we wait and try again with exponential backoff
|
|
time.Sleep(backoffTimeout(attempt))
|
|
continue
|
|
}
|
|
|
|
// check if the connection was refused or dropped
|
|
if strings.Contains(e.Error(), "connection refused") {
|
|
return nil, provider.ErrConnectionClosed
|
|
}
|
|
|
|
// else, as a catch all, we return the error as a bad light block response
|
|
return nil, provider.ErrBadLightBlock{Reason: e}
|
|
|
|
case *rpctypes.RPCError:
|
|
// process the rpc error and return the corresponding error to the light client
|
|
return nil, p.parseRPCError(e)
|
|
|
|
default:
|
|
// check if the error stems from the context
|
|
if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
|
|
return nil, err
|
|
}
|
|
|
|
// If we don't know the error then by default we return an unreliable provider error and
|
|
// terminate the connection with the peer.
|
|
return nil, provider.ErrUnreliableProvider{Reason: e.Error()}
|
|
}
|
|
}
|
|
return nil, p.noResponse()
|
|
}
|
|
|
|
func (p *http) noResponse() error {
|
|
p.noResponseCount++
|
|
if p.noResponseCount > p.noResponseThreshold {
|
|
return provider.ErrUnreliableProvider{
|
|
Reason: fmt.Sprintf("failed to respond after %d attempts", p.noResponseCount),
|
|
}
|
|
}
|
|
return provider.ErrNoResponse
|
|
}
|
|
|
|
func (p *http) noBlock(e error) error {
|
|
p.noBlockCount++
|
|
if p.noBlockCount > p.noBlockThreshold {
|
|
return provider.ErrUnreliableProvider{
|
|
Reason: fmt.Sprintf("failed to provide a block after %d attempts", p.noBlockCount),
|
|
}
|
|
}
|
|
return e
|
|
}
|
|
|
|
// parseRPCError process the error and return the corresponding error to the light clent
|
|
// NOTE: When an error is sent over the wire it gets "flattened" hence we are unable to use error
|
|
// checking functions like errors.Is() to unwrap the error.
|
|
func (p *http) parseRPCError(e *rpctypes.RPCError) error {
|
|
switch {
|
|
// 1) check if the error indicates that the peer doesn't have the block
|
|
case strings.Contains(e.Data, ctypes.ErrHeightNotAvailable.Error()):
|
|
return p.noBlock(provider.ErrLightBlockNotFound)
|
|
|
|
// 2) check if the height requested is too high
|
|
case strings.Contains(e.Data, ctypes.ErrHeightExceedsChainHead.Error()):
|
|
return p.noBlock(provider.ErrHeightTooHigh)
|
|
|
|
// 3) check if the provider closed the connection
|
|
case strings.Contains(e.Data, "connection refused"):
|
|
return provider.ErrConnectionClosed
|
|
|
|
// 4) else return a generic error
|
|
default:
|
|
return provider.ErrBadLightBlock{Reason: e}
|
|
}
|
|
}
|
|
|
|
func validateHeight(height int64) (*int64, error) {
|
|
if height < 0 {
|
|
return nil, fmt.Errorf("expected height >= 0, got height %d", height)
|
|
}
|
|
|
|
h := &height
|
|
if height == 0 {
|
|
h = nil
|
|
}
|
|
return h, nil
|
|
}
|
|
|
|
// exponential backoff (with jitter)
|
|
// 0.5s -> 2s -> 4.5s -> 8s -> 12.5 with 1s variation
|
|
func backoffTimeout(attempt uint16) time.Duration {
|
|
// nolint:gosec // G404: Use of weak random number generator
|
|
return time.Duration(500*attempt*attempt)*time.Millisecond + time.Duration(rand.Intn(1000))*time.Millisecond
|
|
}
|