github.com/ConsenSys/Quorum@v20.10.0+incompatible/consensus/istanbul/core/prepare.go (about)

     1  // Copyright 2017 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package core
    18  
    19  import (
    20  	"reflect"
    21  
    22  	"github.com/ethereum/go-ethereum/consensus/istanbul"
    23  )
    24  
    25  func (c *core) sendPrepare() {
    26  	logger := c.logger.New("state", c.state)
    27  
    28  	sub := c.current.Subject()
    29  	encodedSubject, err := Encode(sub)
    30  	if err != nil {
    31  		logger.Error("Failed to encode", "subject", sub)
    32  		return
    33  	}
    34  	c.broadcast(&message{
    35  		Code: msgPrepare,
    36  		Msg:  encodedSubject,
    37  	})
    38  }
    39  
    40  func (c *core) handlePrepare(msg *message, src istanbul.Validator) error {
    41  	// Decode PREPARE message
    42  	var prepare *istanbul.Subject
    43  	err := msg.Decode(&prepare)
    44  	if err != nil {
    45  		return errFailedDecodePrepare
    46  	}
    47  
    48  	if err := c.checkMessage(msgPrepare, prepare.View); err != nil {
    49  		return err
    50  	}
    51  
    52  	// If it is locked, it can only process on the locked block.
    53  	// Passing verifyPrepare and checkMessage implies it is processing on the locked block since it was verified in the Preprepared state.
    54  	if err := c.verifyPrepare(prepare, src); err != nil {
    55  		return err
    56  	}
    57  
    58  	c.acceptPrepare(msg, src)
    59  
    60  	// Change to Prepared state if we've received enough PREPARE messages or it is locked
    61  	// and we are in earlier state before Prepared state.
    62  	if ((c.current.IsHashLocked() && prepare.Digest == c.current.GetLockedHash()) || c.current.GetPrepareOrCommitSize() >= c.QuorumSize()) &&
    63  		c.state.Cmp(StatePrepared) < 0 {
    64  		c.current.LockHash()
    65  		c.setState(StatePrepared)
    66  		c.sendCommit()
    67  	}
    68  
    69  	return nil
    70  }
    71  
    72  // verifyPrepare verifies if the received PREPARE message is equivalent to our subject
    73  func (c *core) verifyPrepare(prepare *istanbul.Subject, src istanbul.Validator) error {
    74  	logger := c.logger.New("from", src, "state", c.state)
    75  
    76  	sub := c.current.Subject()
    77  	if !reflect.DeepEqual(prepare, sub) {
    78  		logger.Warn("Inconsistent subjects between PREPARE and proposal", "expected", sub, "got", prepare)
    79  		return errInconsistentSubject
    80  	}
    81  
    82  	return nil
    83  }
    84  
    85  func (c *core) acceptPrepare(msg *message, src istanbul.Validator) error {
    86  	logger := c.logger.New("from", src, "state", c.state)
    87  
    88  	// Add the PREPARE message to current round state
    89  	if err := c.current.Prepares.Add(msg); err != nil {
    90  		logger.Error("Failed to add PREPARE message to round state", "msg", msg, "err", err)
    91  		return err
    92  	}
    93  
    94  	return nil
    95  }