gnunet-go

GNUnet Bindings for Go
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service.go (3079B)

      1 // This file is part of gnunet-go, a GNUnet-implementation in Golang.
      2 // Copyright (C) 2019-2022 Bernd Fix  >Y<
      3 //
      4 // gnunet-go is free software: you can redistribute it and/or modify it
      5 // under the terms of the GNU Affero General Public License as published
      6 // by the Free Software Foundation, either version 3 of the License,
      7 // or (at your option) any later version.
      8 //
      9 // gnunet-go is distributed in the hope that it will be useful, but
     10 // WITHOUT ANY WARRANTY; without even the implied warranty of
     11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12 // Affero General Public License for more details.
     13 //
     14 // You should have received a copy of the GNU Affero General Public License
     15 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
     16 //
     17 // SPDX-License-Identifier: AGPL3.0-or-later
     18 
     19 package dht
     20 
     21 import (
     22 	"context"
     23 	"fmt"
     24 	"io"
     25 	"time"
     26 
     27 	"gnunet/config"
     28 	"gnunet/core"
     29 	"gnunet/service"
     30 
     31 	"github.com/bfix/gospel/logger"
     32 )
     33 
     34 // Error codes
     35 var (
     36 	ErrInvalidID           = fmt.Errorf("invalid/unassociated ID")
     37 	ErrBlockExpired        = fmt.Errorf("block expired")
     38 	ErrInvalidResponseType = fmt.Errorf("invald response type")
     39 )
     40 
     41 // Time constants
     42 var (
     43 	DefaultGetTTL   = 10 * time.Minute // timeout for GET requests
     44 	DiscoveryPeriod = 5 * time.Minute  // time between peer discovery runs
     45 )
     46 
     47 //----------------------------------------------------------------------
     48 // "GNUnet R5N DHT" service implementation
     49 //----------------------------------------------------------------------
     50 
     51 // Service implements a DHT service
     52 type Service struct {
     53 	Module
     54 }
     55 
     56 // NewService creates a new DHT service instance
     57 func NewService(ctx context.Context, c *core.Core, cfg *config.DHTConfig) (*Service, error) {
     58 	mod, err := NewModule(ctx, c, cfg)
     59 	if err != nil {
     60 		return nil, err
     61 	}
     62 	srv := &Service{
     63 		Module: *mod,
     64 	}
     65 	return srv, nil
     66 }
     67 
     68 // ServeClient processes a client channel.
     69 func (s *Service) ServeClient(ctx context.Context, id int, mc *service.Connection) {
     70 	reqID := 0
     71 	var cancel context.CancelFunc
     72 	ctx, cancel = context.WithCancel(ctx)
     73 
     74 loop:
     75 	for {
     76 		// receive next message from client
     77 		reqID++
     78 		logger.Printf(logger.DBG, "[dht:%d:%d] Waiting for client request...\n", id, reqID)
     79 		msg, err := mc.Receive(ctx)
     80 		if err != nil {
     81 			if err == io.EOF {
     82 				logger.Printf(logger.INFO, "[dht:%d:%d] Client channel closed.\n", id, reqID)
     83 			} else if err == service.ErrConnectionInterrupted {
     84 				logger.Printf(logger.INFO, "[dht:%d:%d] Service operation interrupted.\n", id, reqID)
     85 			} else {
     86 				logger.Printf(logger.ERROR, "[dht:%d:%d] Message-receive failed: %s\n", id, reqID, err.Error())
     87 			}
     88 			break loop
     89 		}
     90 		logger.Printf(logger.INFO, "[dht:%d:%d] Received request: %v\n", id, reqID, msg)
     91 
     92 		// handle message
     93 		valueCtx := context.WithValue(ctx, core.CtxKey("label"), fmt.Sprintf(":%d:%d", id, reqID))
     94 		s.HandleMessage(valueCtx, nil, msg, mc)
     95 	}
     96 	// close client connection
     97 	mc.Close()
     98 
     99 	// cancel all tasks running for this session/connection
    100 	logger.Printf(logger.INFO, "[dht:%d] Start closing session...\n", id)
    101 	cancel()
    102 }