path: root/whisper/mailserver/mailserver.go

// Copyright 2016 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package mailserver

import (
    "bytes"
    "encoding/binary"

    "github.com/ethereum/go-ethereum/cmd/utils"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/rlp"
    whisper "github.com/ethereum/go-ethereum/whisper/whisperv5"
    "github.com/syndtr/goleveldb/leveldb"
    "github.com/syndtr/goleveldb/leveldb/util"
)

const MailServerKeyName = "958e04ab302fb36ad2616a352cbac79d"

type WMailServer struct {
    db  *leveldb.DB
    w   *whisper.Whisper
    pow float64
    key []byte
}

type DBKey struct {
    timestamp uint32
    hash      common.Hash
    raw       []byte
}

func NewDbKey(t uint32, h common.Hash) *DBKey {
    const sz = common.HashLength + 4
    var k DBKey
    k.timestamp = t
    k.hash = h
    k.raw = make([]byte, sz)
    binary.BigEndian.PutUint32(k.raw, k.timestamp)
    copy(k.raw[4:], k.hash[:])
    return &k
}

func (s *WMailServer) Init(shh *whisper.Whisper, path string, password string, pow float64) {
    var err error
    if len(path) == 0 {
        utils.Fatalf("DB file is not specified")
    }

    if len(password) == 0 {
        utils.Fatalf("Password is not specified for MailServer")
    }

    s.db, err = leveldb.OpenFile(path, nil)
    if err != nil {
        utils.Fatalf("Failed to open DB file: %s", err)
    }

    s.w = shh
    s.pow = pow

    err = s.w.AddSymKey(MailServerKeyName, []byte(password))
    if err != nil {
        utils.Fatalf("Failed to create symmetric key for MailServer: %s", err)
    }
    s.key = s.w.GetSymKey(MailServerKeyName)
}

func (s *WMailServer) Close() {
    if s.db != nil {
        s.db.Close()
    }
}

func (s *WMailServer) Archive(env *whisper.Envelope) {
    key := NewDbKey(env.Expiry-env.TTL, env.Hash())
    rawEnvelope, err := rlp.EncodeToBytes(env)
    if err != nil {
        glog.V(logger.Error).Infof("rlp.EncodeToBytes failed: %s", err)
    } else {
        err = s.db.Put(key.raw, rawEnvelope, nil)
        if err != nil {
            glog.V(logger.Error).Infof("Writing to DB failed: %s", err)
        }
    }
}

func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope) {
    ok, lower, upper, topic := s.validate(peer, request)
    if !ok {
        return
    }

    var err error
    var zero common.Hash
    var empty whisper.TopicType
    kl := NewDbKey(lower, zero)
    ku := NewDbKey(upper, zero)
    i := s.db.NewIterator(&util.Range{Start: kl.raw, Limit: ku.raw}, nil)
    defer i.Release()

    for i.Next() {
        var envelope whisper.Envelope
        err = rlp.DecodeBytes(i.Value(), &envelope)
        if err != nil {
            glog.V(logger.Error).Infof("RLP decoding failed: %s", err)
        }

        if topic == empty || envelope.Topic == topic {
            err = s.w.SendP2PDirect(peer, &envelope)
            if err != nil {
                glog.V(logger.Error).Infof("Failed to send direct message to peer: %s", err)
                return
            }
        }
    }

    err = i.Error()
    if err != nil {
        glog.V(logger.Error).Infof("Level DB iterator error: %s", err)
    }
}

func (s *WMailServer) validate(peer *whisper.Peer, request *whisper.Envelope) (bool, uint32, uint32, whisper.TopicType) {
    var topic whisper.TopicType
    if s.pow > 0.0 && request.PoW() < s.pow {
        return false, 0, 0, topic
    }

    f := whisper.Filter{KeySym: s.key}
    decrypted := request.Open(&f)
    if decrypted == nil {
        glog.V(logger.Warn).Infof("Failed to decrypt p2p request")
        return false, 0, 0, topic
    }

    if len(decrypted.Payload) < 8 {
        glog.V(logger.Warn).Infof("Undersized p2p request")
        return false, 0, 0, topic
    }

    if bytes.Equal(peer.ID(), decrypted.Signature) {
        glog.V(logger.Warn).Infof("Wrong signature of p2p request")
        return false, 0, 0, topic
    }

    lower := binary.BigEndian.Uint32(decrypted.Payload[:4])
    upper := binary.BigEndian.Uint32(decrypted.Payload[4:8])

    if len(decrypted.Payload) >= 8+whisper.TopicLength {
        topic = whisper.BytesToTopic(decrypted.Payload[8:])
    }

    return true, lower, upper, topic
}