policy.cpp File Reference

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

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Functions
CAmount	GetDustThreshold (const CTxOut &txout, const CFeeRate &dustRelayFeeIn)
CAmount	GetDustThreshold (const CFeeRate &dustRelayFeeIn)
bool	IsDust (const CTxOut &txout, const CFeeRate &dustRelayFeeIn)
CAmount	GetShieldedDustThreshold (const CFeeRate &dustRelayFeeIn)
bool	IsStandard (const CScript &scriptPubKey, txnouttype &whichType)
	Check transaction inputs to mitigate two potential denial-of-service attacks: More...
bool	IsStandardTx (const CTransactionRef &tx, int nBlockHeight, std::string &reason)
	Check for standard transaction types. More...
bool	AreInputsStandard (const CTransaction &tx, const CCoinsViewCache &mapInputs)
	Check for standard transaction types. More...

Variables
bool	fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG
CFeeRate	dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE)

Function Documentation

AreInputsStandard()

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

Check for standard transaction types.

Parameters

[in]

mapInputs

Map of previous transactions that have outputs we're spending

Returns

True if all inputs (scriptSigs) use only standard transaction forms

Definition at line 191 of file policy.cpp.

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GetDustThreshold() [1/2]

CAmount GetDustThreshold

(

const CFeeRate &

dustRelayFeeIn

)

Definition at line 39 of file policy.cpp.

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GetDustThreshold() [2/2]

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

Definition at line 21 of file policy.cpp.

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GetShieldedDustThreshold()

CAmount GetShieldedDustThreshold

(

const CFeeRate &

dustRelayFeeIn

)

Definition at line 50 of file policy.cpp.

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IsDust()

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

Definition at line 45 of file policy.cpp.

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IsStandard()

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

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

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

Check transaction inputs, and make sure any pay-to-script-hash transactions are evaluating IsStandard scripts

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 78 of file policy.cpp.

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IsStandardTx()

bool IsStandardTx	(	const CTransactionRef &	tx,
		int	nBlockHeight,
		std::string &	reason
	)

Check for standard transaction types.

Returns

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

Definition at line 100 of file policy.cpp.

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Variable Documentation

dustRelayFee

CFeeRate dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE)

Definition at line 19 of file policy.cpp.

fIsBareMultisigStd

bool fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG

Definition at line 17 of file policy.cpp.