policy.cpp File Reference

#include "policy/policy.h"
#include "consensus/validation.h"
#include "validation.h"
#include "coins.h"
#include "tinyformat.h"
#include "util.h"
#include "utilstrencodings.h"

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Functions
CAmount	GetDustThreshold (const CTxOut &txout, const CFeeRate &dustRelayFeeIn)
bool	IsDust (const CTxOut &txout, const CFeeRate &dustRelayFeeIn)
bool	IsStandard (const CScript &scriptPubKey, txnouttype &whichType, const bool witnessEnabled)
bool	IsStandardTx (const CTransaction &tx, std::string &reason, const bool witnessEnabled)
	Check for standard transaction types. More...
bool	AreInputsStandard (const CTransaction &tx, const CCoinsViewCache &mapInputs)
	Check transaction inputs to mitigate two potential denial-of-service attacks: More...
bool	IsWitnessStandard (const CTransaction &tx, const CCoinsViewCache &mapInputs)
	Check if the transaction is over standard P2WSH resources limit: 3600bytes witnessScript size, 80bytes per witness stack element, 100 witness stack elements These limits are adequate for multi-signature up to n-of-100 using OP_CHECKSIG, OP_ADD, and OP_EQUAL,. More...
int64_t	GetVirtualTransactionSize (int64_t nWeight, int64_t nSigOpCost)
	Compute the virtual transaction size (weight reinterpreted as bytes). More...
int64_t	GetVirtualTransactionSize (const CTransaction &tx, int64_t nSigOpCost)

Variables
CFeeRate	incrementalRelayFee = CFeeRate(DEFAULT_INCREMENTAL_RELAY_FEE)
CFeeRate	dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE)
unsigned int	nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP

Function Documentation

AreInputsStandard()

bool AreInputsStandard	(	const CTransaction &	tx,
		const CCoinsViewCache &	mapInputs
	)

Check transaction inputs to mitigate two potential denial-of-service attacks:

Check for standard transaction types.

1. scriptSigs with extra data stuffed into them, not consumed by scriptPubKey (or P2SH script)
2. P2SH scripts with a crazy number of expensive CHECKSIG/CHECKMULTISIG operations

Why bother? To avoid denial-of-service attacks; an attacker can submit a standard HASH... OP_EQUAL transaction, which will get accepted into blocks. The redemption script can be anything; an attacker could use a very expensive-to-check-upon-redemption script like: DUP CHECKSIG DROP ... repeated 100 times... OP_1

Definition at line 176 of file policy.cpp.

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GetDustThreshold()

CAmount GetDustThreshold	(	const CTxOut &	txout,
		const CFeeRate &	dustRelayFeeIn
	)

Definition at line 19 of file policy.cpp.

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GetVirtualTransactionSize() [1/2]

int64_t GetVirtualTransactionSize	(	int64_t	nWeight,
		int64_t	nSigOpCost
	)

Compute the virtual transaction size (weight reinterpreted as bytes).

Definition at line 266 of file policy.cpp.

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GetVirtualTransactionSize() [2/2]

int64_t GetVirtualTransactionSize	(	const CTransaction &	tx,
		int64_t	nSigOpCost
	)

Definition at line 271 of file policy.cpp.

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IsDust()

bool IsDust	(	const CTxOut &	txout,
		const CFeeRate &	dustRelayFeeIn
	)

Definition at line 53 of file policy.cpp.

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IsStandard()

bool IsStandard	(	const CScript &	scriptPubKey,
		txnouttype &	whichType,
		const bool	witnessEnabled
	)

Definition at line 62 of file policy.cpp.

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IsStandardTx()

bool IsStandardTx	(	const CTransaction &	tx,
		std::string &	reason,
		const bool	witnessEnabled = false
	)

Check for standard transaction types.

Returns

True if all outputs (scriptPubKeys) use only standard transaction forms

Definition at line 87 of file policy.cpp.

IsWitnessStandard()

bool IsWitnessStandard	(	const CTransaction &	tx,
		const CCoinsViewCache &	mapInputs
	)

Check if the transaction is over standard P2WSH resources limit: 3600bytes witnessScript size, 80bytes per witness stack element, 100 witness stack elements These limits are adequate for multi-signature up to n-of-100 using OP_CHECKSIG, OP_ADD, and OP_EQUAL,.

Definition at line 210 of file policy.cpp.

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Variable Documentation

dustRelayFee

CFeeRate dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE)

Definition at line 263 of file policy.cpp.

incrementalRelayFee

CFeeRate incrementalRelayFee = CFeeRate(DEFAULT_INCREMENTAL_RELAY_FEE)

Definition at line 262 of file policy.cpp.

nBytesPerSigOp

unsigned int nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP

Definition at line 264 of file policy.cpp.