go-ethereum/rpc/errors.go
mmsqe f3314bb6df
rpc: add limit for batch request items and response size (#26681)
This PR adds server-side limits for JSON-RPC batch requests. Before this change, batches
were limited only by processing time. The server would pick calls from the batch and
answer them until the response timeout occurred, then stop processing the remaining batch
items.

Here, we are adding two additional limits which can be configured:

- the 'item limit': batches can have at most N items
- the 'response size limit': batches can contain at most X response bytes

These limits are optional in package rpc. In Geth, we set a default limit of 1000 items
and 25MB response size.

When a batch goes over the limit, an error response is returned to the client. However,
doing this correctly isn't always possible. In JSON-RPC, only method calls with a valid
`id` can be responded to. Since batches may also contain non-call messages or
notifications, the best effort thing we can do to report an error with the batch itself is
reporting the limit violation as an error for the first method call in the batch. If a batch is
too large, but contains only notifications and responses, the error will be reported with
a null `id`.

The RPC client was also changed so it can deal with errors resulting from too large
batches. An older client connected to the server code in this PR could get stuck
until the request timeout occurred when the batch is too large. **Upgrading to a version
of the RPC client containing this change is strongly recommended to avoid timeout issues.**

For some weird reason, when writing the original client implementation, @fjl worked off of
the assumption that responses could be distributed across batches arbitrarily. So for a
batch request containing requests `[A B C]`, the server could respond with `[A B C]` but
also with `[A B] [C]` or even `[A] [B] [C]` and it wouldn't make a difference to the
client.

So in the implementation of BatchCallContext, the client waited for all requests in the
batch individually. If the server didn't respond to some of the requests in the batch, the
client would eventually just time out (if a context was used).

With the addition of batch limits into the server, we anticipate that people will hit this
kind of error way more often. To handle this properly, the client now waits for a single
response batch and expects it to contain all responses to the requests.

---------

Co-authored-by: Felix Lange <fjl@twurst.com>
Co-authored-by: Martin Holst Swende <martin@swende.se>
2023-06-13 13:38:58 +02:00

128 lines
3.9 KiB
Go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package rpc
import "fmt"
// HTTPError is returned by client operations when the HTTP status code of the
// response is not a 2xx status.
type HTTPError struct {
StatusCode int
Status string
Body []byte
}
func (err HTTPError) Error() string {
if len(err.Body) == 0 {
return err.Status
}
return fmt.Sprintf("%v: %s", err.Status, err.Body)
}
// Error wraps RPC errors, which contain an error code in addition to the message.
type Error interface {
Error() string // returns the message
ErrorCode() int // returns the code
}
// A DataError contains some data in addition to the error message.
type DataError interface {
Error() string // returns the message
ErrorData() interface{} // returns the error data
}
// Error types defined below are the built-in JSON-RPC errors.
var (
_ Error = new(methodNotFoundError)
_ Error = new(subscriptionNotFoundError)
_ Error = new(parseError)
_ Error = new(invalidRequestError)
_ Error = new(invalidMessageError)
_ Error = new(invalidParamsError)
_ Error = new(internalServerError)
)
const (
errcodeDefault = -32000
errcodeNotificationsUnsupported = -32001
errcodeTimeout = -32002
errcodeResponseTooLarge = -32003
errcodePanic = -32603
errcodeMarshalError = -32603
)
const (
errMsgTimeout = "request timed out"
errMsgResponseTooLarge = "response too large"
errMsgBatchTooLarge = "batch too large"
)
type methodNotFoundError struct{ method string }
func (e *methodNotFoundError) ErrorCode() int { return -32601 }
func (e *methodNotFoundError) Error() string {
return fmt.Sprintf("the method %s does not exist/is not available", e.method)
}
type subscriptionNotFoundError struct{ namespace, subscription string }
func (e *subscriptionNotFoundError) ErrorCode() int { return -32601 }
func (e *subscriptionNotFoundError) Error() string {
return fmt.Sprintf("no %q subscription in %s namespace", e.subscription, e.namespace)
}
// Invalid JSON was received by the server.
type parseError struct{ message string }
func (e *parseError) ErrorCode() int { return -32700 }
func (e *parseError) Error() string { return e.message }
// received message isn't a valid request
type invalidRequestError struct{ message string }
func (e *invalidRequestError) ErrorCode() int { return -32600 }
func (e *invalidRequestError) Error() string { return e.message }
// received message is invalid
type invalidMessageError struct{ message string }
func (e *invalidMessageError) ErrorCode() int { return -32700 }
func (e *invalidMessageError) Error() string { return e.message }
// unable to decode supplied params, or an invalid number of parameters
type invalidParamsError struct{ message string }
func (e *invalidParamsError) ErrorCode() int { return -32602 }
func (e *invalidParamsError) Error() string { return e.message }
// internalServerError is used for server errors during request processing.
type internalServerError struct {
code int
message string
}
func (e *internalServerError) ErrorCode() int { return e.code }
func (e *internalServerError) Error() string { return e.message }