mirror of
https://github.com/FlipsideCrypto/dcrd.git
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9c6dfab8da
This makes messages maximum payload length calculations accurate. In wire messages which contain arrays, the array items counter is variable integer (varInt). Since we limit items count in the arrays, the maximum size of these counters is limited, this causes these counters encoded size in all cases be lower than maximum integer encoded size (MaxVarIntPayload). This commit makes this calculations accurate and makes them consistent with the rest of the codebase.
113 lines
3.2 KiB
Go
113 lines
3.2 KiB
Go
// Copyright (c) 2013-2015 The btcsuite developers
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// Copyright (c) 2015-2019 The Decred developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package wire
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import (
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"fmt"
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"io"
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)
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// MsgNotFound defines a Decred notfound message which is sent in response to
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// a getdata message if any of the requested data in not available on the peer.
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// Each message is limited to a maximum number of inventory vectors, which is
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// currently 50,000.
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//
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// Use the AddInvVect function to build up the list of inventory vectors when
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// sending a notfound message to another peer.
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type MsgNotFound struct {
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InvList []*InvVect
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}
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// AddInvVect adds an inventory vector to the message.
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func (msg *MsgNotFound) AddInvVect(iv *InvVect) error {
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if len(msg.InvList)+1 > MaxInvPerMsg {
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str := fmt.Sprintf("too many invvect in message [max %v]",
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MaxInvPerMsg)
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return messageError("MsgNotFound.AddInvVect", str)
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}
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msg.InvList = append(msg.InvList, iv)
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return nil
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}
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// BtcDecode decodes r using the Decred protocol encoding into the receiver.
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// This is part of the Message interface implementation.
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func (msg *MsgNotFound) BtcDecode(r io.Reader, pver uint32) error {
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count, err := ReadVarInt(r, pver)
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if err != nil {
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return err
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}
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// Limit to max inventory vectors per message.
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if count > MaxInvPerMsg {
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str := fmt.Sprintf("too many invvect in message [%v]", count)
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return messageError("MsgNotFound.BtcDecode", str)
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}
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// Create a contiguous slice of inventory vectors to deserialize into in
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// order to reduce the number of allocations.
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invList := make([]InvVect, count)
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msg.InvList = make([]*InvVect, 0, count)
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for i := uint64(0); i < count; i++ {
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iv := &invList[i]
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err := readInvVect(r, pver, iv)
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if err != nil {
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return err
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}
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msg.AddInvVect(iv)
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}
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return nil
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}
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// BtcEncode encodes the receiver to w using the Decred protocol encoding.
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// This is part of the Message interface implementation.
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func (msg *MsgNotFound) BtcEncode(w io.Writer, pver uint32) error {
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// Limit to max inventory vectors per message.
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count := len(msg.InvList)
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if count > MaxInvPerMsg {
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str := fmt.Sprintf("too many invvect in message [%v]", count)
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return messageError("MsgNotFound.BtcEncode", str)
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}
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err := WriteVarInt(w, pver, uint64(count))
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if err != nil {
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return err
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}
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for _, iv := range msg.InvList {
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err := writeInvVect(w, pver, iv)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Command returns the protocol command string for the message. This is part
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// of the Message interface implementation.
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func (msg *MsgNotFound) Command() string {
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return CmdNotFound
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}
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// MaxPayloadLength returns the maximum length the payload can be for the
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// receiver. This is part of the Message interface implementation.
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func (msg *MsgNotFound) MaxPayloadLength(pver uint32) uint32 {
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// Num inventory vectors (varInt) 3 bytes + max allowed inventory vectors (
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// 36 bytes each).
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return uint32(VarIntSerializeSize(MaxInvPerMsg)) + (MaxInvPerMsg *
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maxInvVectPayload)
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}
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// NewMsgNotFound returns a new Decred notfound message that conforms to the
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// Message interface. See MsgNotFound for details.
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func NewMsgNotFound() *MsgNotFound {
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return &MsgNotFound{
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InvList: make([]*InvVect, 0, defaultInvListAlloc),
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}
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}
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