les: light client protocol and API

1 files changed, 156 insertions, 0 deletions

diff --git a/les/txrelay.go b/les/txrelay.go
new file mode 100644
index 000000000..2df2fa0a9
--- /dev/null
+++ b/les/txrelay.go
@@ -0,0 +1,156 @@
+// Copyright 2015 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 les
+
+import (
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+type ltrInfo struct {
+	tx     *types.Transaction
+	sentTo map[*peer]struct{}
+}
+
+type LesTxRelay struct {
+	txSent       map[common.Hash]*ltrInfo
+	txPending    map[common.Hash]struct{}
+	ps           *peerSet
+	peerList     []*peer
+	peerStartPos int
+	lock         sync.RWMutex
+}
+
+func NewLesTxRelay() *LesTxRelay {
+	return &LesTxRelay{
+		txSent:    make(map[common.Hash]*ltrInfo),
+		txPending: make(map[common.Hash]struct{}),
+		ps:        newPeerSet(),
+	}
+}
+
+func (self *LesTxRelay) addPeer(p *peer) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	self.ps.Register(p)
+	self.peerList = self.ps.AllPeers()
+}
+
+func (self *LesTxRelay) removePeer(id string) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	self.ps.Unregister(id)
+	self.peerList = self.ps.AllPeers()
+}
+
+// send sends a list of transactions to at most a given number of peers at
+// once, never resending any particular transaction to the same peer twice
+func (self *LesTxRelay) send(txs types.Transactions, count int) {
+	sendTo := make(map[*peer]types.Transactions)
+
+	self.peerStartPos++ // rotate the starting position of the peer list
+	if self.peerStartPos >= len(self.peerList) {
+		self.peerStartPos = 0
+	}
+
+	for _, tx := range txs {
+		hash := tx.Hash()
+		ltr, ok := self.txSent[hash]
+		if !ok {
+			ltr = &ltrInfo{
+				tx:     tx,
+				sentTo: make(map[*peer]struct{}),
+			}
+			self.txSent[hash] = ltr
+			self.txPending[hash] = struct{}{}
+		}
+
+		if len(self.peerList) > 0 {
+			cnt := count
+			pos := self.peerStartPos
+			for {
+				peer := self.peerList[pos]
+				if _, ok := ltr.sentTo[peer]; !ok {
+					sendTo[peer] = append(sendTo[peer], tx)
+					ltr.sentTo[peer] = struct{}{}
+					cnt--
+				}
+				if cnt == 0 {
+					break // sent it to the desired number of peers
+				}
+				pos++
+				if pos == len(self.peerList) {
+					pos = 0
+				}
+				if pos == self.peerStartPos {
+					break // tried all available peers
+				}
+			}
+		}
+	}
+
+	for p, list := range sendTo {
+		cost := p.GetRequestCost(SendTxMsg, len(list))
+		go func(p *peer, list types.Transactions, cost uint64) {
+			p.fcServer.SendRequest(0, cost)
+			p.SendTxs(cost, list)
+		}(p, list, cost)
+	}
+}
+
+func (self *LesTxRelay) Send(txs types.Transactions) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	self.send(txs, 3)
+}
+
+func (self *LesTxRelay) NewHead(head common.Hash, mined []common.Hash, rollback []common.Hash) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	for _, hash := range mined {
+		delete(self.txPending, hash)
+	}
+
+	for _, hash := range rollback {
+		self.txPending[hash] = struct{}{}
+	}
+
+	if len(self.txPending) > 0 {
+		txs := make(types.Transactions, len(self.txPending))
+		i := 0
+		for hash, _ := range self.txPending {
+			txs[i] = self.txSent[hash].tx
+			i++
+		}
+		self.send(txs, 1)
+	}
+}
+
+func (self *LesTxRelay) Discard(hashes []common.Hash) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	for _, hash := range hashes {
+		delete(self.txSent, hash)
+		delete(self.txPending, hash)
+	}
+}