1 files changed, 74 insertions, 0 deletions
diff --git a/core/dao.go b/core/dao.go
new file mode 100644
index 000000000..e315c9884
--- /dev/null
+++ b/core/dao.go
@@ -0,0 +1,74 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	"bytes"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+// ValidateDAOHeaderExtraData validates the extra-data field of a block header to
+// ensure it conforms to DAO hard-fork rules.
+//
+// DAO hard-fork extension to the header validity:
+//   a) if the node is no-fork, do not accept blocks in the [fork, fork+10) range
+//      with the fork specific extra-data set
+//   b) if the node is pro-fork, require blocks in the specific range to have the
+//      unique extra-data set.
+func ValidateDAOHeaderExtraData(config *ChainConfig, header *types.Header) error {
+	// Short circuit validation if the node doesn't care about the DAO fork
+	if config.DAOForkBlock == nil {
+		return nil
+	}
+	// Make sure the block is within the fork's modified extra-data range
+	limit := new(big.Int).Add(config.DAOForkBlock, params.DAOForkExtraRange)
+	if header.Number.Cmp(config.DAOForkBlock) < 0 || header.Number.Cmp(limit) >= 0 {
+		return nil
+	}
+	// Depending whether we support or oppose the fork, validate the extra-data contents
+	if config.DAOForkSupport {
+		if bytes.Compare(header.Extra, params.DAOForkBlockExtra) != 0 {
+			return ValidationError("DAO pro-fork bad block extra-data: 0x%x", header.Extra)
+		}
+	} else {
+		if bytes.Compare(header.Extra, params.DAOForkBlockExtra) == 0 {
+			return ValidationError("DAO no-fork bad block extra-data: 0x%x", header.Extra)
+		}
+	}
+	// All ok, header has the same extra-data we expect
+	return nil
+}
+
+// ApplyDAOHardFork modifies the state database according to the DAO hard-fork
+// rules, transferring all balances of a set of DAO accounts to a single refund
+// contract.
+func ApplyDAOHardFork(statedb *state.StateDB) {
+	// Retrieve the contract to refund balances into
+	refund := statedb.GetOrNewStateObject(params.DAORefundContract)
+
+	// Move every DAO account and extra-balance account funds into the refund contract
+	for _, addr := range params.DAODrainList {
+		if account := statedb.GetStateObject(addr); account != nil {
+			refund.AddBalance(account.Balance())
+			account.SetBalance(new(big.Int))
+		}
+	}
+}