package yggdrasil // TODO cleanup, this file is kind of a mess // Commented code should be removed // Live code should be better commented // FIXME (!) this part may be at least sligtly vulnerable to replay attacks // The switch message part should catch / drop old tstamps // So the damage is limited // But you could still mess up msgAnc / msgHops and break some things there // It needs to ignore messages with a lower seq // Probably best to start setting seq to a timestamp in that case... // FIXME (!?) if it takes too long to communicate all the msgHops, then things hit a horizon // That could happen with a peer over a high-latency link, with many msgHops // Possible workarounds: // 1. Pre-emptively send all hops when one is requested, or after any change // Maybe requires changing how the throttle works and msgHops are saved // In case some arrive out of order or are dropped // This is relatively easy to implement, but could be wasteful // 2. Save your old locator, sigs, etc, so you can respond to older ancs // And finish requesting an old anc before updating to a new one // But that may lead to other issues if not done carefully... import "time" import "sync" import "sync/atomic" import "math" //import "fmt" type peers struct { core *Core mutex sync.Mutex // Synchronize writes to atomic ports atomic.Value //map[Port]*peer, use CoW semantics //ports map[Port]*peer } func (ps *peers) init(c *Core) { ps.mutex.Lock() defer ps.mutex.Unlock() ps.putPorts(make(map[switchPort]*peer)) ps.core = c } func (ps *peers) getPorts() map[switchPort]*peer { return ps.ports.Load().(map[switchPort]*peer) } func (ps *peers) putPorts(ports map[switchPort]*peer) { ps.ports.Store(ports) } type peer struct { // Rolling approximation of bandwidth, in bps, used by switch, updated by packet sends // use get/update methods only! (atomic accessors as float64) bandwidth uint64 // BUG: sync/atomic, 32 bit platforms need the above to be the first element box boxPubKey sig sigPubKey shared boxSharedKey //in <-chan []byte //out chan<- []byte //in func([]byte) out func([]byte) core *Core port switchPort msgAnc *msgAnnounce msgHops []*msgHop myMsg *switchMessage mySigs []sigInfo // This is used to limit how often we perform expensive operations // Specifically, processing switch messages, signing, and verifying sigs // Resets at the start of each tick throttle uint8 } const peer_Throttle = 1 func (p *peer) getBandwidth() float64 { bits := atomic.LoadUint64(&p.bandwidth) return math.Float64frombits(bits) } func (p *peer) updateBandwidth(bytes int, duration time.Duration) { if p == nil { return } for ok := false; !ok; { oldBits := atomic.LoadUint64(&p.bandwidth) oldBandwidth := math.Float64frombits(oldBits) bandwidth := oldBandwidth*7/8 + float64(bytes)/duration.Seconds() bits := math.Float64bits(bandwidth) ok = atomic.CompareAndSwapUint64(&p.bandwidth, oldBits, bits) } } func (ps *peers) newPeer(box *boxPubKey, sig *sigPubKey) *peer { //in <-chan []byte, //out chan<- []byte) *peer { p := peer{box: *box, sig: *sig, shared: *getSharedKey(&ps.core.boxPriv, box), //in: in, //out: out, core: ps.core} ps.mutex.Lock() defer ps.mutex.Unlock() oldPorts := ps.getPorts() newPorts := make(map[switchPort]*peer) for k, v := range oldPorts { newPorts[k] = v } for idx := switchPort(0); true; idx++ { if _, isIn := newPorts[idx]; !isIn { p.port = switchPort(idx) newPorts[p.port] = &p break } } ps.putPorts(newPorts) return &p } func (p *peer) linkLoop(in <-chan []byte) { ticker := time.NewTicker(time.Second) defer ticker.Stop() for { select { case packet, ok := <-in: if !ok { return } p.handleLinkTraffic(packet) case <-ticker.C: { p.throttle = 0 if p.port == 0 { continue } // Don't send announces on selfInterface // Maybe we shouldn't time out, and instead wait for a kill signal? p.myMsg, p.mySigs = p.core.switchTable.createMessage(p.port) p.sendSwitchAnnounce() } } } } func (p *peer) handlePacket(packet []byte, linkIn chan<- []byte) { pType, pTypeLen := wire_decode_uint64(packet) if pTypeLen == 0 { return } switch pType { case wire_Traffic: p.handleTraffic(packet, pTypeLen) case wire_ProtocolTraffic: p.handleTraffic(packet, pTypeLen) case wire_LinkProtocolTraffic: { select { case linkIn <- packet: default: } } default: /*panic(pType) ;*/ return } } func (p *peer) handleTraffic(packet []byte, pTypeLen int) { ttl, ttlLen := wire_decode_uint64(packet[pTypeLen:]) ttlBegin := pTypeLen ttlEnd := pTypeLen + ttlLen coords, coordLen := wire_decode_coords(packet[ttlEnd:]) coordEnd := ttlEnd + coordLen if coordEnd == len(packet) { return } // No payload toPort, newTTL := p.core.switchTable.lookup(coords, ttl) if toPort == p.port { return } to := p.core.peers.getPorts()[toPort] if to == nil { return } newTTLLen := wire_uint64_len(newTTL) // This mutates the packet in-place if the length of the TTL changes! shift := ttlLen - newTTLLen wire_put_uint64(newTTL, packet[ttlBegin+shift:]) copy(packet[shift:], packet[:pTypeLen]) packet = packet[shift:] to.sendPacket(packet) } func (p *peer) sendPacket(packet []byte) { // Is there ever a case where something more complicated is needed? // What if p.out blocks? p.out(packet) } func (p *peer) sendLinkPacket(packet []byte) { bs, nonce := boxSeal(&p.shared, packet, nil) linkPacket := wire_linkProtoTrafficPacket{ toKey: p.box, fromKey: p.core.boxPub, nonce: *nonce, payload: bs, } packet = linkPacket.encode() p.sendPacket(packet) } func (p *peer) handleLinkTraffic(bs []byte) { packet := wire_linkProtoTrafficPacket{} if !packet.decode(bs) { return } if packet.toKey != p.core.boxPub { return } if packet.fromKey != p.box { return } payload, isOK := boxOpen(&p.shared, packet.payload, &packet.nonce) if !isOK { return } pType, pTypeLen := wire_decode_uint64(payload) if pTypeLen == 0 { return } switch pType { case wire_SwitchAnnounce: p.handleSwitchAnnounce(payload) case wire_SwitchHopRequest: p.handleSwitchHopRequest(payload) case wire_SwitchHop: p.handleSwitchHop(payload) } } func (p *peer) handleSwitchAnnounce(packet []byte) { //p.core.log.Println("DEBUG: handleSwitchAnnounce") anc := msgAnnounce{} //err := wire_decode_struct(packet, &anc) //if err != nil { return } if !anc.decode(packet) { return } //if p.msgAnc != nil && anc.Seq != p.msgAnc.Seq { p.msgHops = nil } if p.msgAnc == nil || anc.root != p.msgAnc.root || anc.tstamp != p.msgAnc.tstamp || anc.seq != p.msgAnc.seq { p.msgHops = nil } p.msgAnc = &anc p.processSwitchMessage() } func (p *peer) requestHop(hop uint64) { //p.core.log.Println("DEBUG requestHop") req := msgHopReq{} req.root = p.msgAnc.root req.tstamp = p.msgAnc.tstamp req.seq = p.msgAnc.seq req.hop = hop packet := req.encode() p.sendLinkPacket(packet) } func (p *peer) handleSwitchHopRequest(packet []byte) { //p.core.log.Println("DEBUG: handleSwitchHopRequest") if p.throttle > peer_Throttle { return } if p.myMsg == nil { return } req := msgHopReq{} if !req.decode(packet) { return } if req.root != p.myMsg.locator.root { return } if req.tstamp != p.myMsg.locator.tstamp { return } if req.seq != p.myMsg.seq { return } if uint64(len(p.myMsg.locator.coords)) <= req.hop { return } res := msgHop{} res.root = p.myMsg.locator.root res.tstamp = p.myMsg.locator.tstamp res.seq = p.myMsg.seq res.hop = req.hop res.port = p.myMsg.locator.coords[res.hop] sinfo := p.getSig(res.hop) //p.core.log.Println("DEBUG sig:", sinfo) res.next = sinfo.next res.sig = sinfo.sig packet = res.encode() p.sendLinkPacket(packet) } func (p *peer) handleSwitchHop(packet []byte) { //p.core.log.Println("DEBUG: handleSwitchHop") if p.throttle > peer_Throttle { return } if p.msgAnc == nil { return } res := msgHop{} if !res.decode(packet) { return } if res.root != p.msgAnc.root { return } if res.tstamp != p.msgAnc.tstamp { return } if res.seq != p.msgAnc.seq { return } if res.hop != uint64(len(p.msgHops)) { return } // always process in order loc := switchLocator{coords: make([]switchPort, 0, len(p.msgHops)+1)} loc.root = res.root loc.tstamp = res.tstamp for _, hop := range p.msgHops { loc.coords = append(loc.coords, hop.port) } loc.coords = append(loc.coords, res.port) thisHopKey := &res.root if res.hop != 0 { thisHopKey = &p.msgHops[res.hop-1].next } bs := getBytesForSig(&res.next, &loc) if p.core.sigs.check(thisHopKey, &res.sig, bs) { p.msgHops = append(p.msgHops, &res) p.processSwitchMessage() } else { p.throttle++ } } func (p *peer) processSwitchMessage() { //p.core.log.Println("DEBUG: processSwitchMessage") if p.throttle > peer_Throttle { return } if p.msgAnc == nil { return } if uint64(len(p.msgHops)) < p.msgAnc.len { p.requestHop(uint64(len(p.msgHops))) return } p.throttle++ if p.msgAnc.len != uint64(len(p.msgHops)) { return } msg := switchMessage{} coords := make([]switchPort, 0, len(p.msgHops)) sigs := make([]sigInfo, 0, len(p.msgHops)) for idx, hop := range p.msgHops { // Consistency checks, should be redundant (already checked these...) if hop.root != p.msgAnc.root { return } if hop.tstamp != p.msgAnc.tstamp { return } if hop.seq != p.msgAnc.seq { return } if hop.hop != uint64(idx) { return } coords = append(coords, hop.port) sigs = append(sigs, sigInfo{next: hop.next, sig: hop.sig}) } msg.from = p.sig msg.locator.root = p.msgAnc.root msg.locator.tstamp = p.msgAnc.tstamp msg.locator.coords = coords msg.seq = p.msgAnc.seq //msg.RSeq = p.msgAnc.RSeq //msg.Degree = p.msgAnc.Deg p.core.switchTable.handleMessage(&msg, p.port, sigs) if len(coords) == 0 { return } // Reuse locator, set the coords to the peer's coords, to use in dht msg.locator.coords = coords[:len(coords)-1] // Pass a mesage to the dht informing it that this peer (still) exists dinfo := dhtInfo{ key: p.box, coords: msg.locator.getCoords(), } p.core.dht.peers <- &dinfo } func (p *peer) sendSwitchAnnounce() { anc := msgAnnounce{} anc.root = p.myMsg.locator.root anc.tstamp = p.myMsg.locator.tstamp anc.seq = p.myMsg.seq anc.len = uint64(len(p.myMsg.locator.coords)) //anc.Deg = p.myMsg.Degree //anc.RSeq = p.myMsg.RSeq packet := anc.encode() p.sendLinkPacket(packet) } func (p *peer) getSig(hop uint64) sigInfo { //p.core.log.Println("DEBUG getSig:", len(p.mySigs), hop) if hop < uint64(len(p.mySigs)) { return p.mySigs[hop] } bs := getBytesForSig(&p.sig, &p.myMsg.locator) sig := sigInfo{} sig.next = p.sig sig.sig = *sign(&p.core.sigPriv, bs) p.mySigs = append(p.mySigs, sig) //p.core.log.Println("DEBUG sig bs:", bs) return sig } func getBytesForSig(next *sigPubKey, loc *switchLocator) []byte { //bs, err := wire_encode_locator(loc) //if err != nil { panic(err) } bs := append([]byte(nil), next[:]...) bs = append(bs, wire_encode_locator(loc)...) //bs := wire_encode_locator(loc) //bs = append(next[:], bs...) return bs }