github.com/beyonderyue/gochain@v2.2.26+incompatible/whisper/whisperv5/peer.go (about)

     1  // Copyright 2016 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 whisperv5
    18  
    19  import (
    20  	"fmt"
    21  	"sync"
    22  	"time"
    23  
    24  	"github.com/gochain-io/gochain/common"
    25  	"github.com/gochain-io/gochain/log"
    26  	"github.com/gochain-io/gochain/p2p"
    27  	"github.com/gochain-io/gochain/rlp"
    28  )
    29  
    30  // peer represents a whisper protocol peer connection.
    31  type Peer struct {
    32  	host    *Whisper
    33  	peer    *p2p.Peer
    34  	ws      p2p.MsgReadWriter
    35  	trusted bool
    36  
    37  	knownMu sync.RWMutex
    38  	known   map[common.Hash]struct{} // Messages already known by the peer to avoid wasting bandwidth
    39  
    40  	quit chan struct{}
    41  }
    42  
    43  // newPeer creates a new whisper peer object, but does not run the handshake itself.
    44  func newPeer(host *Whisper, remote *p2p.Peer, rw p2p.MsgReadWriter) *Peer {
    45  	return &Peer{
    46  		host:    host,
    47  		peer:    remote,
    48  		ws:      rw,
    49  		trusted: false,
    50  		known:   make(map[common.Hash]struct{}),
    51  		quit:    make(chan struct{}),
    52  	}
    53  }
    54  
    55  // start initiates the peer updater, periodically broadcasting the whisper packets
    56  // into the network.
    57  func (p *Peer) start() {
    58  	go p.update()
    59  	log.Trace("start", "peer", p.ID())
    60  }
    61  
    62  // stop terminates the peer updater, stopping message forwarding to it.
    63  func (p *Peer) stop() {
    64  	close(p.quit)
    65  	log.Trace("stop", "peer", p.ID())
    66  }
    67  
    68  // handshake sends the protocol initiation status message to the remote peer and
    69  // verifies the remote status too.
    70  func (p *Peer) handshake() error {
    71  	// Send the handshake status message asynchronously
    72  	errc := make(chan error, 1)
    73  	go func() {
    74  		errc <- p2p.Send(p.ws, statusCode, ProtocolVersion)
    75  	}()
    76  	// Fetch the remote status packet and verify protocol match
    77  	packet, err := p.ws.ReadMsg()
    78  	if err != nil {
    79  		return err
    80  	}
    81  	if packet.Code != statusCode {
    82  		return fmt.Errorf("peer [%x] sent packet %x before status packet", p.ID(), packet.Code)
    83  	}
    84  	s := rlp.NewStream(packet.Payload, uint64(packet.Size))
    85  	peerVersion, err := s.Uint()
    86  	if err != nil {
    87  		return fmt.Errorf("peer [%x] sent bad status message: %v", p.ID(), err)
    88  	}
    89  	if peerVersion != ProtocolVersion {
    90  		return fmt.Errorf("peer [%x]: protocol version mismatch %d != %d", p.ID(), peerVersion, ProtocolVersion)
    91  	}
    92  	// Wait until out own status is consumed too
    93  	if err := <-errc; err != nil {
    94  		return fmt.Errorf("peer [%x] failed to send status packet: %v", p.ID(), err)
    95  	}
    96  	return nil
    97  }
    98  
    99  // update executes periodic operations on the peer, including message transmission
   100  // and expiration.
   101  func (p *Peer) update() {
   102  	// Start the tickers for the updates
   103  	expire := time.NewTicker(expirationCycle)
   104  	transmit := time.NewTicker(transmissionCycle)
   105  
   106  	// Loop and transmit until termination is requested
   107  	for {
   108  		select {
   109  		case <-expire.C:
   110  			p.expire()
   111  
   112  		case <-transmit.C:
   113  			if err := p.broadcast(); err != nil {
   114  				log.Trace("broadcast failed", "reason", err, "peer", p.ID())
   115  				return
   116  			}
   117  
   118  		case <-p.quit:
   119  			return
   120  		}
   121  	}
   122  }
   123  
   124  // mark marks an envelope known to the peer so that it won't be sent back.
   125  func (peer *Peer) mark(envelope *Envelope) {
   126  	h := envelope.Hash()
   127  	peer.knownMu.Lock()
   128  	peer.known[h] = struct{}{}
   129  	peer.knownMu.Unlock()
   130  }
   131  
   132  // marked checks if an envelope is already known to the remote peer.
   133  func (peer *Peer) marked(envelope *Envelope) bool {
   134  	h := envelope.Hash()
   135  	peer.knownMu.RLock()
   136  	_, ok := peer.known[h]
   137  	peer.knownMu.RUnlock()
   138  	return ok
   139  }
   140  
   141  // expire iterates over all the known envelopes in the host and removes all
   142  // expired (unknown) ones from the known list.
   143  func (peer *Peer) expire() {
   144  	unmark := make(map[common.Hash]struct{})
   145  	peer.knownMu.Lock()
   146  	defer peer.knownMu.Unlock()
   147  	for h := range peer.known {
   148  		if !peer.host.isEnvelopeCached(h) {
   149  			unmark[h] = struct{}{}
   150  		}
   151  	}
   152  	// Dump all known but no longer cached
   153  	for hash := range unmark {
   154  		delete(peer.known, hash)
   155  	}
   156  }
   157  
   158  // broadcast iterates over the collection of envelopes and transmits yet unknown
   159  // ones over the network.
   160  func (p *Peer) broadcast() error {
   161  	var cnt int
   162  	envelopes := p.host.Envelopes()
   163  	for _, envelope := range envelopes {
   164  		if !p.marked(envelope) {
   165  			err := p2p.Send(p.ws, messagesCode, envelope)
   166  			if err != nil {
   167  				return err
   168  			} else {
   169  				p.mark(envelope)
   170  				cnt++
   171  			}
   172  		}
   173  	}
   174  	if cnt > 0 {
   175  		log.Trace("broadcast", "num. messages", cnt)
   176  	}
   177  	return nil
   178  }
   179  
   180  func (p *Peer) ID() []byte {
   181  	id := p.peer.ID()
   182  	return id[:]
   183  }