src/script/standard.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2016 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #ifndef BITCOIN_SCRIPT_STANDARD_H
   7 #define BITCOIN_SCRIPT_STANDARD_H
   8
   9 #include <script/interpreter.h>
  10 #include <uint256.h>
  11
  12 #include <boost/variant.hpp>
  13
  14 #include <stdint.h>
  15
  16 static const bool DEFAULT_ACCEPT_DATACARRIER = true;
  17
  18 class CKeyID;
  19 class CScript;
  20
  21 /** A reference to a CScript: the Hash160 of its serialization (see script.h) */
  22 class CScriptID : public uint160
  23 {
  24 public:
  25     CScriptID() : uint160() {}
  26     CScriptID(const CScript& in);
  27     CScriptID(const uint160& in) : uint160(in) {}
  28 };
  29
  30 /**
  31  * Default setting for nMaxDatacarrierBytes. 80 bytes of data, +1 for OP_RETURN,
  32  * +2 for the pushdata opcodes.
  33  */
  34 static const unsigned int MAX_OP_RETURN_RELAY = 83;
  35
  36 /**
  37  * A data carrying output is an unspendable output containing data. The script
  38  * type is designated as TX_NULL_DATA.
  39  */
  40 extern bool fAcceptDatacarrier;
  41
  42 /** Maximum size of TX_NULL_DATA scripts that this node considers standard. */
  43 extern unsigned nMaxDatacarrierBytes;
  44
  45 /**
  46  * Mandatory script verification flags that all new blocks must comply with for
  47  * them to be valid. (but old blocks may not comply with) Currently just P2SH,
  48  * but in the future other flags may be added, such as a soft-fork to enforce
  49  * strict DER encoding.
  50  *
  51  * Failing one of these tests may trigger a DoS ban - see CheckInputs() for
  52  * details.
  53  */
  54 static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH;
  55
  56 enum txnouttype
  57 {
  58     TX_NONSTANDARD,
  59     // 'standard' transaction types:
  60     TX_PUBKEY,
  61     TX_PUBKEYHASH,
  62     TX_SCRIPTHASH,
  63     TX_MULTISIG,
  64     TX_NULL_DATA, //!< unspendable OP_RETURN script that carries data
  65     TX_WITNESS_V0_SCRIPTHASH,
  66     TX_WITNESS_V0_KEYHASH,
  67     TX_WITNESS_UNKNOWN, //!< Only for Witness versions not already defined above
  68 };
  69
  70 class CNoDestination {
  71 public:
  72     friend bool operator==(const CNoDestination &a, const CNoDestination &b) { return true; }
  73     friend bool operator<(const CNoDestination &a, const CNoDestination &b) { return true; }
  74 };
  75
  76 struct WitnessV0ScriptHash : public uint256 {};
  77 struct WitnessV0KeyHash : public uint160 {};
  78
  79 //! CTxDestination subtype to encode any future Witness version
  80 struct WitnessUnknown
  81 {
  82     unsigned int version;
  83     unsigned int length;
  84     unsigned char program[40];
  85
  86     friend bool operator==(const WitnessUnknown& w1, const WitnessUnknown& w2) {
  87         if (w1.version != w2.version) return false;
  88         if (w1.length != w2.length) return false;
  89         return std::equal(w1.program, w1.program + w1.length, w2.program);
  90     }
  91
  92     friend bool operator<(const WitnessUnknown& w1, const WitnessUnknown& w2) {
  93         if (w1.version < w2.version) return true;
  94         if (w1.version > w2.version) return false;
  95         if (w1.length < w2.length) return true;
  96         if (w1.length > w2.length) return false;
  97         return std::lexicographical_compare(w1.program, w1.program + w1.length, w2.program, w2.program + w2.length);
  98     }
  99 };
 100
 101 /**
 102  * A txout script template with a specific destination. It is either:
 103  *  * CNoDestination: no destination set
 104  *  * CKeyID: TX_PUBKEYHASH destination (P2PKH)
 105  *  * CScriptID: TX_SCRIPTHASH destination (P2SH)
 106  *  * WitnessV0ScriptHash: TX_WITNESS_V0_SCRIPTHASH destination (P2WSH)
 107  *  * WitnessV0KeyHash: TX_WITNESS_V0_KEYHASH destination (P2WPKH)
 108  *  * WitnessUnknown: TX_WITNESS_UNKNOWN destination (P2W???)
 109  *  A CTxDestination is the internal data type encoded in a bitcoin address
 110  */
 111 typedef boost::variant<CNoDestination, CKeyID, CScriptID, WitnessV0ScriptHash, WitnessV0KeyHash, WitnessUnknown> CTxDestination;
 112
 113 /** Check whether a CTxDestination is a CNoDestination. */
 114 bool IsValidDestination(const CTxDestination& dest);
 115
 116 /** Get the name of a txnouttype as a C string, or nullptr if unknown. */
 117 const char* GetTxnOutputType(txnouttype t);
 118
 119 /**
 120  * Parse a scriptPubKey and identify script type for standard scripts. If
 121  * successful, returns script type and parsed pubkeys or hashes, depending on
 122  * the type. For example, for a P2SH script, vSolutionsRet will contain the
 123  * script hash, for P2PKH it will contain the key hash, etc.
 124  *
 125  * @param[in]   scriptPubKey   Script to parse
 126  * @param[out]  typeRet        The script type
 127  * @param[out]  vSolutionsRet  Vector of parsed pubkeys and hashes
 128  * @return                     True if script matches standard template
 129  */
 130 bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<std::vector<unsigned char> >& vSolutionsRet);
 131
 132 /**
 133  * Parse a standard scriptPubKey for the destination address. Assigns result to
 134  * the addressRet parameter and returns true if successful. For multisig
 135  * scripts, instead use ExtractDestinations. Currently only works for P2PK,
 136  * P2PKH, P2SH, P2WPKH, and P2WSH scripts.
 137  */
 138 bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet);
 139
 140 /**
 141  * Parse a standard scriptPubKey with one or more destination addresses. For
 142  * multisig scripts, this populates the addressRet vector with the pubkey IDs
 143  * and nRequiredRet with the n required to spend. For other destinations,
 144  * addressRet is populated with a single value and nRequiredRet is set to 1.
 145  * Returns true if successful. Currently does not extract address from
 146  * pay-to-witness scripts.
 147  */
 148 bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<CTxDestination>& addressRet, int& nRequiredRet);
 149
 150 /**
 151  * Generate a Bitcoin scriptPubKey for the given CTxDestination. Returns a P2PKH
 152  * script for a CKeyID destination, a P2SH script for a CScriptID, and an empty
 153  * script for CNoDestination.
 154  */
 155 CScript GetScriptForDestination(const CTxDestination& dest);
 156
 157 /** Generate a P2PK script for the given pubkey. */
 158 CScript GetScriptForRawPubKey(const CPubKey& pubkey);
 159
 160 /** Generate a multisig script. */
 161 CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys);
 162
 163 /**
 164  * Generate a pay-to-witness script for the given redeem script. If the redeem
 165  * script is P2PK or P2PKH, this returns a P2WPKH script, otherwise it returns a
 166  * P2WSH script.
 167  */
 168 CScript GetScriptForWitness(const CScript& redeemscript);
 169
 170 #endif // BITCOIN_SCRIPT_STANDARD_H