package yggdrasil import ( "errors" "fmt" "sync" "sync/atomic" "time" "github.com/yggdrasil-network/yggdrasil-go/src/crypto" "github.com/yggdrasil-network/yggdrasil-go/src/util" ) // ConnError implements the net.Error interface type ConnError struct { error timeout bool temporary bool closed bool maxsize int } // Timeout returns true if the error relates to a timeout condition on the // connection. func (e *ConnError) Timeout() bool { return e.timeout } // Temporary return true if the error is temporary or false if it is a permanent // error condition. func (e *ConnError) Temporary() bool { return e.temporary } // PacketTooBig returns in response to sending a packet that is too large, and // if so, the maximum supported packet size that should be used for the // connection. func (e *ConnError) PacketTooBig() bool { return e.maxsize > 0 } // PacketMaximumSize returns the maximum supported packet size. This will only // return a non-zero value if ConnError.PacketTooBig() returns true. func (e *ConnError) PacketMaximumSize() int { if !e.PacketTooBig() { return 0 } return e.maxsize } // Closed returns if the session is already closed and is now unusable. func (e *ConnError) Closed() bool { return e.closed } type Conn struct { core *Core readDeadline atomic.Value // time.Time // TODO timer writeDeadline atomic.Value // time.Time // TODO timer cancel util.Cancellation mutex sync.RWMutex // protects the below nodeID *crypto.NodeID nodeMask *crypto.NodeID session *sessionInfo } // TODO func NewConn() that initializes additional fields as needed func newConn(core *Core, nodeID *crypto.NodeID, nodeMask *crypto.NodeID, session *sessionInfo) *Conn { conn := Conn{ core: core, nodeID: nodeID, nodeMask: nodeMask, session: session, cancel: util.NewCancellation(), } return &conn } func (c *Conn) String() string { c.mutex.RLock() defer c.mutex.RUnlock() return fmt.Sprintf("conn=%p", c) } // This should never be called from the router goroutine, used in the dial functions func (c *Conn) search() error { var sinfo *searchInfo var isIn bool c.core.router.doAdmin(func() { sinfo, isIn = c.core.searches.searches[*c.nodeID] }) if !isIn { done := make(chan struct{}, 1) var sess *sessionInfo var err error searchCompleted := func(sinfo *sessionInfo, e error) { sess = sinfo err = e // FIXME close can be called multiple times, do a non-blocking send instead select { case done <- struct{}{}: default: } } c.core.router.doAdmin(func() { sinfo = c.core.searches.newIterSearch(c.nodeID, c.nodeMask, searchCompleted) sinfo.continueSearch() }) <-done c.session = sess if c.session == nil && err == nil { panic("search failed but returned no error") } if c.session != nil { c.nodeID = crypto.GetNodeID(&c.session.theirPermPub) for i := range c.nodeMask { c.nodeMask[i] = 0xFF } } return err } else { return errors.New("search already exists") } return nil } // Used in session keep-alive traffic in Conn.Write func (c *Conn) doSearch() { routerWork := func() { // Check to see if there is a search already matching the destination sinfo, isIn := c.core.searches.searches[*c.nodeID] if !isIn { // Nothing was found, so create a new search searchCompleted := func(sinfo *sessionInfo, e error) {} sinfo = c.core.searches.newIterSearch(c.nodeID, c.nodeMask, searchCompleted) c.core.log.Debugf("%s DHT search started: %p", c.String(), sinfo) } // Continue the search sinfo.continueSearch() } go func() { c.core.router.admin <- routerWork }() } func (c *Conn) getDeadlineCancellation(value *atomic.Value) util.Cancellation { if deadline, ok := value.Load().(time.Time); ok { // A deadline is set, so return a Cancellation that uses it return util.CancellationWithDeadline(c.cancel, deadline) } else { // No cancellation was set, so return a child cancellation with no timeout return util.CancellationChild(c.cancel) } } func (c *Conn) Read(b []byte) (int, error) { // Take a copy of the session object sinfo := c.session cancel := c.getDeadlineCancellation(&c.readDeadline) defer cancel.Cancel(nil) for { // Wait for some traffic to come through from the session select { case <-cancel.Finished(): if cancel.Error() == util.CancellationTimeoutError { return 0, ConnError{errors.New("read timeout"), true, false, false, 0} } else { return 0, ConnError{errors.New("session closed"), false, false, true, 0} } case bs := <-sinfo.recv: var err error n := len(bs) if len(bs) > len(b) { n = len(b) err = ConnError{errors.New("read buffer too small for entire packet"), false, true, false, 0} } // Copy results to the output slice and clean up copy(b, bs) util.PutBytes(bs) // If we've reached this point then everything went to plan, return the // number of bytes we populated back into the given slice return n, err } } } func (c *Conn) Write(b []byte) (bytesWritten int, err error) { sinfo := c.session written := len(b) sessionFunc := func() { // Does the packet exceed the permitted size for the session? if uint16(len(b)) > sinfo.getMTU() { written, err = 0, ConnError{errors.New("packet too big"), true, false, false, int(sinfo.getMTU())} return } // The rest of this work is session keep-alive traffic switch { case time.Since(sinfo.time) > 6*time.Second: if sinfo.time.Before(sinfo.pingTime) && time.Since(sinfo.pingTime) > 6*time.Second { // TODO double check that the above condition is correct c.doSearch() } else { sinfo.core.sessions.ping(sinfo) } case sinfo.reset && sinfo.pingTime.Before(sinfo.time): sinfo.core.sessions.ping(sinfo) default: // Don't do anything, to keep traffic throttled } } sinfo.doFunc(sessionFunc) if written > 0 { bs := append(util.GetBytes(), b...) sinfo.send <- bs } return written, err } func (c *Conn) Close() (err error) { c.mutex.Lock() defer c.mutex.Unlock() if c.session != nil { // Close the session, if it hasn't been closed already c.core.router.doAdmin(c.session.close) } if e := c.cancel.Cancel(errors.New("connection closed")); e != nil { err = ConnError{errors.New("close failed, session already closed"), false, false, true, 0} } return } func (c *Conn) LocalAddr() crypto.NodeID { return *crypto.GetNodeID(&c.session.core.boxPub) } func (c *Conn) RemoteAddr() crypto.NodeID { c.mutex.RLock() defer c.mutex.RUnlock() return *c.nodeID } func (c *Conn) SetDeadline(t time.Time) error { c.SetReadDeadline(t) c.SetWriteDeadline(t) return nil } func (c *Conn) SetReadDeadline(t time.Time) error { c.readDeadline.Store(t) return nil } func (c *Conn) SetWriteDeadline(t time.Time) error { c.writeDeadline.Store(t) return nil }