go-ethereum/rlp/raw.go
Felix Lange 7194c847b6
p2p/rlpx: reduce allocation and syscalls (#22899)
This change significantly improves the performance of RLPx message reads
and writes. In the previous implementation, reading and writing of
message frames performed multiple reads and writes on the underlying
network connection, and allocated a new []byte buffer for every read.

In the new implementation, reads and writes re-use buffers, and perform
much fewer system calls on the underlying connection. This doubles the
theoretically achievable throughput on a single connection, as shown by
the benchmark result:

    name             old speed      new speed       delta
    Throughput-8     70.3MB/s ± 0%  155.4MB/s ± 0%  +121.11%  (p=0.000 n=9+8)

The change also removes support for the legacy, pre-EIP-8 handshake encoding.
As of May 2021, no actively maintained client sends this format.
2021-05-27 10:19:13 +02:00

262 lines
6.2 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 rlp
import (
"io"
"reflect"
)
// RawValue represents an encoded RLP value and can be used to delay
// RLP decoding or to precompute an encoding. Note that the decoder does
// not verify whether the content of RawValues is valid RLP.
type RawValue []byte
var rawValueType = reflect.TypeOf(RawValue{})
// ListSize returns the encoded size of an RLP list with the given
// content size.
func ListSize(contentSize uint64) uint64 {
return uint64(headsize(contentSize)) + contentSize
}
// IntSize returns the encoded size of the integer x.
func IntSize(x uint64) int {
if x < 0x80 {
return 1
}
return 1 + intsize(x)
}
// Split returns the content of first RLP value and any
// bytes after the value as subslices of b.
func Split(b []byte) (k Kind, content, rest []byte, err error) {
k, ts, cs, err := readKind(b)
if err != nil {
return 0, nil, b, err
}
return k, b[ts : ts+cs], b[ts+cs:], nil
}
// SplitString splits b into the content of an RLP string
// and any remaining bytes after the string.
func SplitString(b []byte) (content, rest []byte, err error) {
k, content, rest, err := Split(b)
if err != nil {
return nil, b, err
}
if k == List {
return nil, b, ErrExpectedString
}
return content, rest, nil
}
// SplitUint64 decodes an integer at the beginning of b.
// It also returns the remaining data after the integer in 'rest'.
func SplitUint64(b []byte) (x uint64, rest []byte, err error) {
content, rest, err := SplitString(b)
if err != nil {
return 0, b, err
}
switch {
case len(content) == 0:
return 0, rest, nil
case len(content) == 1:
if content[0] == 0 {
return 0, b, ErrCanonInt
}
return uint64(content[0]), rest, nil
case len(content) > 8:
return 0, b, errUintOverflow
default:
x, err = readSize(content, byte(len(content)))
if err != nil {
return 0, b, ErrCanonInt
}
return x, rest, nil
}
}
// SplitList splits b into the content of a list and any remaining
// bytes after the list.
func SplitList(b []byte) (content, rest []byte, err error) {
k, content, rest, err := Split(b)
if err != nil {
return nil, b, err
}
if k != List {
return nil, b, ErrExpectedList
}
return content, rest, nil
}
// CountValues counts the number of encoded values in b.
func CountValues(b []byte) (int, error) {
i := 0
for ; len(b) > 0; i++ {
_, tagsize, size, err := readKind(b)
if err != nil {
return 0, err
}
b = b[tagsize+size:]
}
return i, nil
}
func readKind(buf []byte) (k Kind, tagsize, contentsize uint64, err error) {
if len(buf) == 0 {
return 0, 0, 0, io.ErrUnexpectedEOF
}
b := buf[0]
switch {
case b < 0x80:
k = Byte
tagsize = 0
contentsize = 1
case b < 0xB8:
k = String
tagsize = 1
contentsize = uint64(b - 0x80)
// Reject strings that should've been single bytes.
if contentsize == 1 && len(buf) > 1 && buf[1] < 128 {
return 0, 0, 0, ErrCanonSize
}
case b < 0xC0:
k = String
tagsize = uint64(b-0xB7) + 1
contentsize, err = readSize(buf[1:], b-0xB7)
case b < 0xF8:
k = List
tagsize = 1
contentsize = uint64(b - 0xC0)
default:
k = List
tagsize = uint64(b-0xF7) + 1
contentsize, err = readSize(buf[1:], b-0xF7)
}
if err != nil {
return 0, 0, 0, err
}
// Reject values larger than the input slice.
if contentsize > uint64(len(buf))-tagsize {
return 0, 0, 0, ErrValueTooLarge
}
return k, tagsize, contentsize, err
}
func readSize(b []byte, slen byte) (uint64, error) {
if int(slen) > len(b) {
return 0, io.ErrUnexpectedEOF
}
var s uint64
switch slen {
case 1:
s = uint64(b[0])
case 2:
s = uint64(b[0])<<8 | uint64(b[1])
case 3:
s = uint64(b[0])<<16 | uint64(b[1])<<8 | uint64(b[2])
case 4:
s = uint64(b[0])<<24 | uint64(b[1])<<16 | uint64(b[2])<<8 | uint64(b[3])
case 5:
s = uint64(b[0])<<32 | uint64(b[1])<<24 | uint64(b[2])<<16 | uint64(b[3])<<8 | uint64(b[4])
case 6:
s = uint64(b[0])<<40 | uint64(b[1])<<32 | uint64(b[2])<<24 | uint64(b[3])<<16 | uint64(b[4])<<8 | uint64(b[5])
case 7:
s = uint64(b[0])<<48 | uint64(b[1])<<40 | uint64(b[2])<<32 | uint64(b[3])<<24 | uint64(b[4])<<16 | uint64(b[5])<<8 | uint64(b[6])
case 8:
s = uint64(b[0])<<56 | uint64(b[1])<<48 | uint64(b[2])<<40 | uint64(b[3])<<32 | uint64(b[4])<<24 | uint64(b[5])<<16 | uint64(b[6])<<8 | uint64(b[7])
}
// Reject sizes < 56 (shouldn't have separate size) and sizes with
// leading zero bytes.
if s < 56 || b[0] == 0 {
return 0, ErrCanonSize
}
return s, nil
}
// AppendUint64 appends the RLP encoding of i to b, and returns the resulting slice.
func AppendUint64(b []byte, i uint64) []byte {
if i == 0 {
return append(b, 0x80)
} else if i < 128 {
return append(b, byte(i))
}
switch {
case i < (1 << 8):
return append(b, 0x81, byte(i))
case i < (1 << 16):
return append(b, 0x82,
byte(i>>8),
byte(i),
)
case i < (1 << 24):
return append(b, 0x83,
byte(i>>16),
byte(i>>8),
byte(i),
)
case i < (1 << 32):
return append(b, 0x84,
byte(i>>24),
byte(i>>16),
byte(i>>8),
byte(i),
)
case i < (1 << 40):
return append(b, 0x85,
byte(i>>32),
byte(i>>24),
byte(i>>16),
byte(i>>8),
byte(i),
)
case i < (1 << 48):
return append(b, 0x86,
byte(i>>40),
byte(i>>32),
byte(i>>24),
byte(i>>16),
byte(i>>8),
byte(i),
)
case i < (1 << 56):
return append(b, 0x87,
byte(i>>48),
byte(i>>40),
byte(i>>32),
byte(i>>24),
byte(i>>16),
byte(i>>8),
byte(i),
)
default:
return append(b, 0x88,
byte(i>>56),
byte(i>>48),
byte(i>>40),
byte(i>>32),
byte(i>>24),
byte(i>>16),
byte(i>>8),
byte(i),
)
}
}