1// Copyright (c) 2014-2015 The btcsuite developers 2// Use of this source code is governed by an ISC 3// license that can be found in the LICENSE file. 4 5package wire 6 7import ( 8 "fmt" 9 "io" 10) 11 12// BloomUpdateType specifies how the filter is updated when a match is found 13type BloomUpdateType uint8 14 15const ( 16 // BloomUpdateNone indicates the filter is not adjusted when a match is 17 // found. 18 BloomUpdateNone BloomUpdateType = 0 19 20 // BloomUpdateAll indicates if the filter matches any data element in a 21 // public key script, the outpoint is serialized and inserted into the 22 // filter. 23 BloomUpdateAll BloomUpdateType = 1 24 25 // BloomUpdateP2PubkeyOnly indicates if the filter matches a data 26 // element in a public key script and the script is of the standard 27 // pay-to-pubkey or multisig, the outpoint is serialized and inserted 28 // into the filter. 29 BloomUpdateP2PubkeyOnly BloomUpdateType = 2 30) 31 32const ( 33 // MaxFilterLoadHashFuncs is the maximum number of hash functions to 34 // load into the Bloom filter. 35 MaxFilterLoadHashFuncs = 50 36 37 // MaxFilterLoadFilterSize is the maximum size in bytes a filter may be. 38 MaxFilterLoadFilterSize = 36000 39) 40 41// MsgFilterLoad implements the Message interface and represents a bitcoin 42// filterload message which is used to reset a Bloom filter. 43// 44// This message was not added until protocol version BIP0037Version. 45type MsgFilterLoad struct { 46 Filter []byte 47 HashFuncs uint32 48 Tweak uint32 49 Flags BloomUpdateType 50} 51 52// BtcDecode decodes r using the bitcoin protocol encoding into the receiver. 53// This is part of the Message interface implementation. 54func (msg *MsgFilterLoad) BtcDecode(r io.Reader, pver uint32, enc MessageEncoding) error { 55 if pver < BIP0037Version { 56 str := fmt.Sprintf("filterload message invalid for protocol "+ 57 "version %d", pver) 58 return messageError("MsgFilterLoad.BtcDecode", str) 59 } 60 61 var err error 62 msg.Filter, err = ReadVarBytes(r, pver, MaxFilterLoadFilterSize, 63 "filterload filter size") 64 if err != nil { 65 return err 66 } 67 68 err = readElements(r, &msg.HashFuncs, &msg.Tweak, &msg.Flags) 69 if err != nil { 70 return err 71 } 72 73 if msg.HashFuncs > MaxFilterLoadHashFuncs { 74 str := fmt.Sprintf("too many filter hash functions for message "+ 75 "[count %v, max %v]", msg.HashFuncs, MaxFilterLoadHashFuncs) 76 return messageError("MsgFilterLoad.BtcDecode", str) 77 } 78 79 return nil 80} 81 82// BtcEncode encodes the receiver to w using the bitcoin protocol encoding. 83// This is part of the Message interface implementation. 84func (msg *MsgFilterLoad) BtcEncode(w io.Writer, pver uint32, enc MessageEncoding) error { 85 if pver < BIP0037Version { 86 str := fmt.Sprintf("filterload message invalid for protocol "+ 87 "version %d", pver) 88 return messageError("MsgFilterLoad.BtcEncode", str) 89 } 90 91 size := len(msg.Filter) 92 if size > MaxFilterLoadFilterSize { 93 str := fmt.Sprintf("filterload filter size too large for message "+ 94 "[size %v, max %v]", size, MaxFilterLoadFilterSize) 95 return messageError("MsgFilterLoad.BtcEncode", str) 96 } 97 98 if msg.HashFuncs > MaxFilterLoadHashFuncs { 99 str := fmt.Sprintf("too many filter hash functions for message "+ 100 "[count %v, max %v]", msg.HashFuncs, MaxFilterLoadHashFuncs) 101 return messageError("MsgFilterLoad.BtcEncode", str) 102 } 103 104 err := WriteVarBytes(w, pver, msg.Filter) 105 if err != nil { 106 return err 107 } 108 109 return writeElements(w, msg.HashFuncs, msg.Tweak, msg.Flags) 110} 111 112// Command returns the protocol command string for the message. This is part 113// of the Message interface implementation. 114func (msg *MsgFilterLoad) Command() string { 115 return CmdFilterLoad 116} 117 118// MaxPayloadLength returns the maximum length the payload can be for the 119// receiver. This is part of the Message interface implementation. 120func (msg *MsgFilterLoad) MaxPayloadLength(pver uint32) uint32 { 121 // Num filter bytes (varInt) + filter + 4 bytes hash funcs + 122 // 4 bytes tweak + 1 byte flags. 123 return uint32(VarIntSerializeSize(MaxFilterLoadFilterSize)) + 124 MaxFilterLoadFilterSize + 9 125} 126 127// NewMsgFilterLoad returns a new bitcoin filterload message that conforms to 128// the Message interface. See MsgFilterLoad for details. 129func NewMsgFilterLoad(filter []byte, hashFuncs uint32, tweak uint32, flags BloomUpdateType) *MsgFilterLoad { 130 return &MsgFilterLoad{ 131 Filter: filter, 132 HashFuncs: hashFuncs, 133 Tweak: tweak, 134 Flags: flags, 135 } 136} 137