func NewDHTNode(outputChan chan string, port int) *Node {
var err error
node := &Node{
info: &ContactInfo{
Id: GenerateNodeId(),
},
}
// new routing table
node.routing = NewRouting(node)
// init udp network connection.
node.network = new(Network)
udpAddr := new(net.UDPAddr)
udpAddr.Port = port
if node.network.conn, err = net.ListenUDP("udp", udpAddr); err != nil {
panic(err.Error())
}
laddr := node.network.conn.LocalAddr().(*net.UDPAddr)
node.info.IP = laddr.IP
node.info.Port = laddr.Port
// new KRPC
node.krpc = NewKRPC()
// output channel
node.output = outputChan
return node
}
/*
Starts a UDP listener which will forward received data back to the application using
the supplied channel. The listener ID is returned along with a boolean indication
of success (true) or failure. The uid is the user created session id string that is
used to send buffers that are not related to a session_data struct.
*/
func (this *Cmgr) Listen_udp(port int, data2usr chan *Sess_data) (uid string, err error) {
var addr net.UDPAddr
uid = ""
addr.IP = net.IPv4(0, 0, 0, 0)
addr.Port = port
uconn, err := net.ListenUDP("udp", &addr)
if err != nil {
err = fmt.Errorf("unable to create a udp listener on port: %d; %s", port, err)
return
}
uid = fmt.Sprintf("u%d", this.ucount) // successful bind to port
this.ucount += 1
cp := new(connection)
cp.conn = nil
cp.uconn = uconn
cp.data2usr = data2usr // session data written to the channel
cp.id = uid // user assigned session id
this.clist[uid] = cp // hash for write to session
go this.conn_reader(cp) // start reader; will discard if data2usr is nil
this.clist[uid] = cp
return
}
func (dhtNode *DhtNode) FindNode(node *KNode) {
var id Id
if node.Id != nil {
id = node.Id.Neighbor()
} else {
id = dhtNode.node.Id.Neighbor()
}
tid := dhtNode.krpc.GenTID()
v := make(map[string]interface{})
v["t"] = fmt.Sprintf("%d", tid)
v["y"] = "q"
v["q"] = "find_node"
args := make(map[string]string)
args["id"] = string(id)
args["target"] = string(GenerateID())
v["a"] = args
data, err := bencode.EncodeString(v)
if err != nil {
dhtNode.log.Fatalln(err)
}
raddr := new(net.UDPAddr)
raddr.IP = node.Ip
raddr.Port = node.Port
err = dhtNode.network.Send([]byte(data), raddr)
if err != nil {
dhtNode.log.Println(err)
}
}
func (n *network) call(msg []byte, timeout time.Duration) (result []byte, err error) {
var server net.UDPAddr
server.IP = n.gateway
server.Port = nAT_PMP_PORT
conn, err := net.DialUDP("udp", nil, &server)
if err != nil {
return
}
defer conn.Close()
// 16 bytes is the maximum result size.
result = make([]byte, 16)
var finalTimeout time.Time
if timeout != 0 {
finalTimeout = time.Now().Add(timeout)
}
needNewDeadline := true
var tries uint
for tries = 0; (tries < nAT_TRIES && finalTimeout.IsZero()) || time.Now().Before(finalTimeout); {
if needNewDeadline {
nextDeadline := time.Now().Add((nAT_INITIAL_MS << tries) * time.Millisecond)
err = conn.SetDeadline(minTime(nextDeadline, finalTimeout))
if err != nil {
return
}
needNewDeadline = false
}
_, err = conn.Write(msg)
if err != nil {
return
}
var bytesRead int
var remoteAddr *net.UDPAddr
bytesRead, remoteAddr, err = conn.ReadFromUDP(result)
if err != nil {
if err.(net.Error).Timeout() {
tries++
needNewDeadline = true
continue
}
return
}
if !remoteAddr.IP.Equal(n.gateway) {
// Ignore this packet.
// Continue without increasing retransmission timeout or deadline.
continue
}
// Trim result to actual number of bytes received
if bytesRead < len(result) {
result = result[:bytesRead]
}
return
}
err = fmt.Errorf("Timed out trying to contact gateway")
return
}
func forward_tap_to_phys(phys_conn *net.UDPConn, tap_conn *TapConn, peer_addr *net.UDPAddr, key []byte, chan_disc_peer chan net.UDPAddr) {
/* Raw tap frame received */
frame := make([]byte, TAP_MTU+14)
/* Encapsulated frame and error */
var enc_frame []byte
var invalid error = nil
/* Discovered peer */
var disc_peer_addr net.UDPAddr
/* Initialize our HMAC-SHA256 hash context */
hmac_h := hmac.New(sha256.New, key)
/* If a peer was specified, fill in our discovered peer information */
if peer_addr != nil {
disc_peer_addr.IP = peer_addr.IP
disc_peer_addr.Port = peer_addr.Port
} else {
/* Otherwise, wait for the forward_phys_to_tap() goroutine to discover a peer */
disc_peer_addr = <-chan_disc_peer
}
log.Printf("Starting tap->phys forwarding with peer %s:%d...\n", disc_peer_addr.IP, disc_peer_addr.Port)
for {
/* Read a raw frame from our tap device */
n, err := tap_conn.Read(frame)
if err != nil {
log.Fatalf("Error reading from tap device!: %s\n", err)
}
if DEBUG == 2 {
log.Println("<- tap | Plaintext frame to peer:")
log.Println("\n" + hex.Dump(frame[0:n]))
}
/* Encapsulate the frame */
enc_frame, invalid = encap_frame(frame[0:n], hmac_h)
/* Skip it if it's invalid */
if invalid != nil {
if DEBUG >= 1 {
log.Printf("-> phys | Frame discarded! Size: %d, Reason: %s\n", n, invalid.Error())
log.Println("\n" + hex.Dump(frame[0:n]))
}
continue
}
if DEBUG == 2 {
log.Println("-> phys | Encapsulated frame to peer:")
log.Println("\n" + hex.Dump(enc_frame))
}
/* Send the encapsulated frame to our peer through UDP */
_, err = phys_conn.WriteToUDP(enc_frame, &disc_peer_addr)
if err != nil {
log.Fatalf("Error writing to UDP socket!: %s\n", err)
}
}
}
/*------------------------------------------------------------------------
* int OpenPort(ttp_session_t *session);
*
* Creates a new UDP socket for transmitting the file data associated
* with our pending transfer and receives the destination port number
* from the client. Returns 0 on success and non-zero on failure.
*------------------------------------------------------------------------*/
func (session *Session) OpenPort() error {
/* create the address structure */
var udp_address net.UDPAddr
if session.parameter.client == "" {
address := session.client_fd.RemoteAddr()
addr := address.(*net.TCPAddr)
udp_address.IP = addr.IP
udp_address.Zone = addr.Zone
} else {
addr, err := net.ResolveIPAddr("ip", session.parameter.client)
if err != nil {
return err
}
if addr.Network() == "ipv6" {
session.parameter.ipv6 = true
}
udp_address.IP = addr.IP
udp_address.Zone = addr.Zone
}
if udp_address.String() == "" {
return nil
}
/* read in the port number from the client */
buf := make([]byte, 2)
_, err := session.client_fd.Read(buf)
if err != nil {
return err
}
x := binary.BigEndian.Uint16(buf)
udp_address.Port = int(x)
if session.parameter.verbose {
Warn("Sending to client port ", x)
}
fd, err := createUdpSocket(session.parameter, &udp_address)
if err != nil {
return Warn("Could not create UDP socket", err)
}
session.transfer.udp_fd = fd
session.transfer.udp_address = &udp_address
return nil
}
func (dhtNode *KNode) GoFindNode(info *NodeInfo, target Id) {
if info.Ip.Equal(net.IPv4(0, 0, 0, 0)) || info.Port == 0 {
return
}
addr := new(net.UDPAddr)
addr.IP = info.Ip
addr.Port = info.Port
data, err := dhtNode.krpc.EncodingFindNode(target)
if err != nil {
dhtNode.log.Println(err)
return
}
err = dhtNode.network.Send([]byte(data), addr)
if err != nil {
dhtNode.log.Println(err)
return
}
}
// find_node
func (n *Node) Find_Node(queryingNodeInfo *ContactInfo, target ID) error {
if queryingNodeInfo.IP.Equal(net.IPv4(0, 0, 0, 0)) || queryingNodeInfo.Port == 0 {
return errors.New("Can not parse Bootstrap node address.")
}
addr := new(net.UDPAddr)
addr.IP = queryingNodeInfo.IP
addr.Port = queryingNodeInfo.Port
args := make(map[string]interface{})
args["target"] = string(target)
args["id"] = string(n.info.Id)
dat, err := n.krpc.EncodeQueryPackage("find_node", args)
if err != nil {
return err
}
if _, err := n.network.conn.WriteToUDP(dat, addr); err != nil {
return err
}
return nil
}
func (n *Client) rpc(msg []byte, resultSize int) (result []byte, err error) {
var server net.UDPAddr
server.IP = n.gateway
server.Port = nAT_PMP_PORT
conn, err := net.DialUDP("udp", nil, &server)
if err != nil {
return
}
defer conn.Close()
result = make([]byte, resultSize)
timeout := time.Now().Add(n.timeout)
err = conn.SetDeadline(timeout)
if err != nil {
return
}
var bytesRead int
var remoteAddr *net.UDPAddr
for time.Now().Before(timeout) {
_, err = conn.Write(msg)
if err != nil {
return
}
bytesRead, remoteAddr, err = conn.ReadFromUDP(result)
if err != nil {
if err.(net.Error).Timeout() {
continue
}
return
}
if !remoteAddr.IP.Equal(n.gateway) {
// Ignore this packet.
continue
}
if bytesRead != resultSize {
err = fmt.Errorf("unexpected result size %d, expected %d", bytesRead, resultSize)
return
}
if result[0] != 0 {
err = fmt.Errorf("unknown protocol version %d", result[0])
return
}
expectedOp := msg[1] | 0x80
if result[1] != expectedOp {
err = fmt.Errorf("Unexpected opcode %d. Expected %d", result[1], expectedOp)
return
}
resultCode := readNetworkOrderUint16(result[2:4])
if resultCode != 0 {
err = fmt.Errorf("Non-zero result code %d", resultCode)
return
}
// If we got here the RPC is good.
return
}
err = fmt.Errorf("Timed out trying to contact gateway")
return
}
func forward_phys_to_tap(phys_conn *net.UDPConn, tap_conn *TapConn, peer_addr *net.UDPAddr, key []byte, chan_disc_peer chan net.UDPAddr) {
/* Raw UDP packet received */
packet := make([]byte, UDP_MTU)
/* Decapsulated frame and error */
var dec_frame []byte
var invalid error = nil
/* Peer address */
var cur_peer_addr net.UDPAddr
/* Peer discovery */
var peer_discovery bool
/* Initialize our HMAC-SHA256 hash context */
hmac_h := hmac.New(sha256.New, key)
/* If a peer was specified, fill in our peer information */
if peer_addr != nil {
cur_peer_addr.IP = peer_addr.IP
cur_peer_addr.Port = peer_addr.Port
log.Printf("Starting udp->tap forwarding with peer %s:%d...\n", cur_peer_addr.IP, cur_peer_addr.Port)
peer_discovery = false
} else {
log.Printf("Starting udp->tap forwarding with peer discovery...\n")
peer_discovery = true
}
for {
/* Receive an encapsulated frame packet through UDP */
n, raddr, err := phys_conn.ReadFromUDP(packet)
if err != nil {
log.Fatalf("Error reading from UDP socket!: %s\n", err)
}
/* If peer discovery is off, ensure the received packge is from our
* specified peer */
if !peer_discovery && (!raddr.IP.Equal(cur_peer_addr.IP) || raddr.Port != cur_peer_addr.Port) {
continue
}
if DEBUG == 2 {
log.Println("<- udp | Encapsulated frame:")
log.Printf(" | from Peer %s:%d\n", raddr.IP, raddr.Port)
log.Println("\n" + hex.Dump(packet[0:n]))
}
/* Decapsulate the frame, skip it if it's invalid */
dec_frame, invalid = decap_frame(packet[0:n], hmac_h)
if invalid != nil {
if DEBUG >= 1 {
log.Printf("<- udp | Frame discarded! Size: %d, Reason: %s\n", n, invalid.Error())
log.Printf(" | from Peer %s:%d\n", raddr.IP, raddr.Port)
log.Println("\n" + hex.Dump(packet[0:n]))
}
continue
}
/* If peer discovery is on and the peer is new, save the discovered
* peer */
if peer_discovery && (!raddr.IP.Equal(cur_peer_addr.IP) || raddr.Port != cur_peer_addr.Port) {
cur_peer_addr.IP = raddr.IP
cur_peer_addr.Port = raddr.Port
/* Send the new peer info to our forward_tap_to_phys() goroutine
* via channel */
chan_disc_peer <- cur_peer_addr
if DEBUG >= 0 {
log.Printf("Discovered peer %s:%d!\n", cur_peer_addr.IP, cur_peer_addr.Port)
}
}
if DEBUG == 2 {
log.Println("-> tap | Decapsulated frame from peer:")
log.Println("\n" + hex.Dump(dec_frame))
}
/* Forward the decapsulated frame to our tap interface */
_, err = tap_conn.Write(dec_frame)
if err != nil {
log.Fatalf("Error writing to tap device!: %s\n", err)
}
}
}
func (n *Client) rpc(msg []byte, resultSize int) (result []byte, err error) {
var server net.UDPAddr
server.IP = n.gateway
server.Port = nAT_PMP_PORT
conn, err := net.DialUDP("udp", nil, &server)
if err != nil {
return
}
defer conn.Close()
result = make([]byte, resultSize)
needNewDeadline := true
var tries uint
for tries = 0; tries < nAT_TRIES; {
if needNewDeadline {
err = conn.SetDeadline(time.Now().Add((nAT_INITIAL_MS << tries) * time.Millisecond))
if err != nil {
return
}
needNewDeadline = false
}
_, err = conn.Write(msg)
if err != nil {
return
}
var bytesRead int
var remoteAddr *net.UDPAddr
bytesRead, remoteAddr, err = conn.ReadFromUDP(result)
if err != nil {
if err.(net.Error).Timeout() {
tries++
needNewDeadline = true
continue
}
return
}
if !remoteAddr.IP.Equal(n.gateway) {
log.Printf("Ignoring packet because IPs differ:", remoteAddr, n.gateway)
// Ignore this packet.
// Continue without increasing retransmission timeout or deadline.
continue
}
if bytesRead != resultSize {
err = fmt.Errorf("unexpected result size %d, expected %d", bytesRead, resultSize)
return
}
if result[0] != 0 {
err = fmt.Errorf("unknown protocol version %d", result[0])
return
}
expectedOp := msg[1] | 0x80
if result[1] != expectedOp {
err = fmt.Errorf("Unexpected opcode %d. Expected %d", result[1], expectedOp)
return
}
resultCode := readNetworkOrderUint16(result[2:4])
if resultCode != 0 {
err = fmt.Errorf("Non-zero result code %d", resultCode)
return
}
// If we got here the RPC is good.
return
}
err = fmt.Errorf("Timed out trying to contact gateway")
return
}
func forward_phys_to_tap(phys_conn *net.UDPConn, tap_conn *TapConn, peer_addr *net.UDPAddr, key []byte, chan_disc_peer chan net.UDPAddr) {
/* Raw UDP packet received */
packet := make([]byte, UDP_MTU)
/* Decapsulated frame and error */
var dec_frame []byte
var invalid error = nil
/* Discovered peer */
var disc_peer bool = false
var disc_peer_addr net.UDPAddr
/* Initialize our HMAC-SHA256 hash context */
hmac_h := hmac.New(sha256.New, key)
/* If a peer was specified, fill in our discovered peer information */
if peer_addr != nil {
disc_peer = true
disc_peer_addr.IP = peer_addr.IP
disc_peer_addr.Port = peer_addr.Port
log.Printf("Starting phys->tap forwarding with peer %s:%d...\n", disc_peer_addr.IP, disc_peer_addr.Port)
} else {
log.Printf("Starting phys->tap forwarding with peer discovery...\n")
}
for {
/* Receive an encapsulated frame packet through UDP */
n, raddr, err := phys_conn.ReadFromUDP(packet)
if err != nil {
log.Fatalf("Error reading from UDP socket!: %s\n", err)
}
/* Ensure it's addressed from our peer, if we've already discovered
* one */
if disc_peer {
if !raddr.IP.Equal(disc_peer_addr.IP) || raddr.Port != disc_peer_addr.Port {
continue
}
}
if DEBUG == 2 {
log.Println("<- phys | Encapsulated frame from peer:")
log.Println("\n" + hex.Dump(packet[0:n]))
}
/* Decapsulate the frame */
dec_frame, invalid = decap_frame(packet[0:n], hmac_h)
/* Skip it if it's invalid */
if invalid != nil {
if DEBUG >= 1 {
log.Printf("<- phys | Frame discarded! Size: %d, Reason: %s\n", n, invalid.Error())
log.Printf(" | from Peer %s:%d\n", raddr.IP, raddr.Port)
log.Println("\n" + hex.Dump(packet[0:n]))
}
continue
}
/* Save the discovered peer, if it's our first valid decoded packet */
if !disc_peer {
disc_peer_addr.IP = raddr.IP
disc_peer_addr.Port = raddr.Port
disc_peer = true
/* Send the discovered peer info to our forward_tap_to_phys()
* goroutine */
chan_disc_peer <- disc_peer_addr
if DEBUG >= 0 {
log.Printf("Discovered peer %s:%d!\n", disc_peer_addr.IP, disc_peer_addr.Port)
}
}
if DEBUG == 2 {
log.Println("-> tap | Decapsulated frame from peer:")
log.Println("\n" + hex.Dump(dec_frame))
}
/* Forward the decapsulated frame to our tap interface */
_, err = tap_conn.Write(dec_frame)
if err != nil {
log.Fatalf("Error writing to tap device!: %s\n", err)
}
}
}
func changePort(addr *net.UDPAddr, port int) *net.UDPAddr {
addr.Port = port
return addr
}