121 lines
3.7 KiB
Go
121 lines
3.7 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package server
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import (
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"net"
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"strings"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/les/utils"
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"github.com/ethereum/go-ethereum/les/vflux"
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"github.com/ethereum/go-ethereum/log"
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"github.com/ethereum/go-ethereum/p2p/enode"
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"github.com/ethereum/go-ethereum/rlp"
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)
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type (
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// Server serves vflux requests
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Server struct {
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limiter *utils.Limiter
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lock sync.Mutex
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services map[string]*serviceEntry
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delayPerRequest time.Duration
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}
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// Service is a service registered at the Server and identified by a string id
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Service interface {
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Handle(id enode.ID, address string, name string, data []byte) []byte // never called concurrently
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}
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serviceEntry struct {
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id, desc string
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backend Service
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}
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)
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// NewServer creates a new Server
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func NewServer(delayPerRequest time.Duration) *Server {
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return &Server{
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limiter: utils.NewLimiter(1000),
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delayPerRequest: delayPerRequest,
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services: make(map[string]*serviceEntry),
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}
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}
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// Register registers a Service
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func (s *Server) Register(b Service, id, desc string) {
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srv := &serviceEntry{backend: b, id: id, desc: desc}
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if strings.Contains(srv.id, ":") {
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// srv.id + ":" will be used as a service database prefix
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log.Error("Service ID contains ':'", "id", srv.id)
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return
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}
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s.lock.Lock()
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s.services[srv.id] = srv
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s.lock.Unlock()
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}
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// Serve serves a vflux request batch
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// Note: requests are served by the Handle functions of the registered services. Serve
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// may be called concurrently but the Handle functions are called sequentially and
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// therefore thread safety is guaranteed.
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func (s *Server) Serve(id enode.ID, address string, requests vflux.Requests) vflux.Replies {
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reqLen := uint(len(requests))
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if reqLen == 0 || reqLen > vflux.MaxRequestLength {
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return nil
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}
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// Note: the value parameter will be supplied by the token sale module (total amount paid)
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ch := <-s.limiter.Add(id, address, 0, reqLen)
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if ch == nil {
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return nil
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}
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// Note: the limiter ensures that the following section is not running concurrently,
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// the lock only protects against contention caused by new service registration
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s.lock.Lock()
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results := make(vflux.Replies, len(requests))
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for i, req := range requests {
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if service := s.services[req.Service]; service != nil {
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results[i] = service.backend.Handle(id, address, req.Name, req.Params)
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}
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}
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s.lock.Unlock()
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time.Sleep(s.delayPerRequest * time.Duration(reqLen))
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close(ch)
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return results
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}
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// ServeEncoded serves an encoded vflux request batch and returns the encoded replies
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func (s *Server) ServeEncoded(id enode.ID, addr *net.UDPAddr, req []byte) []byte {
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var requests vflux.Requests
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if err := rlp.DecodeBytes(req, &requests); err != nil {
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return nil
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}
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results := s.Serve(id, addr.String(), requests)
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if results == nil {
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return nil
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}
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res, _ := rlp.EncodeToBytes(&results)
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return res
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}
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// Stop shuts down the server
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func (s *Server) Stop() {
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s.limiter.Stop()
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}
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