mirror of
https://github.com/yggdrasil-network/yggdrasil-go.git
synced 2024-12-23 00:17:35 +00:00
399 lines
12 KiB
Go
399 lines
12 KiB
Go
package yggdrasil
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import (
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"errors"
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"fmt"
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"net"
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"time"
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"github.com/yggdrasil-network/yggdrasil-go/src/crypto"
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"github.com/yggdrasil-network/yggdrasil-go/src/types"
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"github.com/yggdrasil-network/yggdrasil-go/src/util"
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"github.com/Arceliar/phony"
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)
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type MTU = types.MTU
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// ConnError implements the net.Error interface
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type ConnError struct {
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error
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timeout bool
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temporary bool
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closed bool
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maxsize int
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}
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// Timeout returns true if the error relates to a timeout condition on the
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// connection.
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func (e *ConnError) Timeout() bool {
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return e.timeout
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}
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// Temporary return true if the error is temporary or false if it is a permanent
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// error condition.
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func (e *ConnError) Temporary() bool {
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return e.temporary
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}
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// PacketTooBig returns in response to sending a packet that is too large, and
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// if so, the maximum supported packet size that should be used for the
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// connection.
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func (e *ConnError) PacketTooBig() bool {
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return e.maxsize > 0
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}
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// PacketMaximumSize returns the maximum supported packet size. This will only
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// return a non-zero value if ConnError.PacketTooBig() returns true.
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func (e *ConnError) PacketMaximumSize() int {
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if !e.PacketTooBig() {
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return 0
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}
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return e.maxsize
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}
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// Closed returns if the session is already closed and is now unusable.
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func (e *ConnError) Closed() bool {
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return e.closed
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}
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// The Conn struct is a reference to an active connection session between the
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// local node and a remote node. Conn implements the io.ReadWriteCloser
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// interface and is used to send and receive traffic with a remote node.
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type Conn struct {
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phony.Inbox
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core *Core
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readDeadline *time.Time
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writeDeadline *time.Time
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nodeID *crypto.NodeID
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nodeMask *crypto.NodeID
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session *sessionInfo
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mtu MTU
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readCallback func([]byte)
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readBuffer chan []byte
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}
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// TODO func NewConn() that initializes additional fields as needed
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func newConn(core *Core, nodeID *crypto.NodeID, nodeMask *crypto.NodeID, session *sessionInfo) *Conn {
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conn := Conn{
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core: core,
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nodeID: nodeID,
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nodeMask: nodeMask,
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session: session,
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readBuffer: make(chan []byte, 1024),
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}
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return &conn
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}
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// String returns a string that uniquely identifies a connection. Currently this
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// takes a form similar to "conn=0x0000000", which contains a memory reference
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// to the Conn object. While this value should always be unique for each Conn
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// object, the format of this is not strictly defined and may change in the
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// future.
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func (c *Conn) String() string {
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var s string
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phony.Block(c, func() { s = fmt.Sprintf("conn=%p", c) })
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return s
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}
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func (c *Conn) setMTU(from phony.Actor, mtu MTU) {
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c.Act(from, func() { c.mtu = mtu })
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}
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// This should never be called from an actor, used in the dial functions
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func (c *Conn) search() error {
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var err error
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done := make(chan struct{})
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phony.Block(&c.core.router, func() {
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_, isIn := c.core.router.searches.searches[*c.nodeID]
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if !isIn {
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searchCompleted := func(sinfo *sessionInfo, e error) {
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select {
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case <-done:
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// Somehow this was called multiple times, TODO don't let that happen
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if sinfo != nil {
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// Need to clean up to avoid a session leak
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sinfo.cancel.Cancel(nil)
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sinfo.sessions.removeSession(sinfo)
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}
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default:
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if sinfo != nil {
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// Finish initializing the session
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c.session = sinfo
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c.session.setConn(nil, c)
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c.nodeID = crypto.GetNodeID(&c.session.theirPermPub)
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for i := range c.nodeMask {
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c.nodeMask[i] = 0xFF
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}
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}
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err = e
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close(done)
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}
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}
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sinfo := c.core.router.searches.newIterSearch(c.nodeID, c.nodeMask, searchCompleted)
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sinfo.startSearch()
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} else {
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err = errors.New("search already exists")
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close(done)
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}
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})
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<-done
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if c.session == nil && err == nil {
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panic("search failed but returned no error")
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}
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return err
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}
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// Used in session keep-alive traffic
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func (c *Conn) doSearch() {
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routerWork := func() {
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// Check to see if there is a search already matching the destination
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sinfo, isIn := c.core.router.searches.searches[*c.nodeID]
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if !isIn {
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// Nothing was found, so create a new search
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searchCompleted := func(sinfo *sessionInfo, e error) {}
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sinfo = c.core.router.searches.newIterSearch(c.nodeID, c.nodeMask, searchCompleted)
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c.core.log.Debugf("%s DHT search started: %p", c.String(), sinfo)
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// Start the search
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sinfo.startSearch()
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}
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}
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c.core.router.Act(c.session, routerWork)
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}
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func (c *Conn) _getDeadlineCancellation(t *time.Time) (util.Cancellation, bool) {
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if t != nil {
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// A deadline is set, so return a Cancellation that uses it
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c := util.CancellationWithDeadline(c.session.cancel, *t)
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return c, true
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} else {
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// No deadline was set, so just return the existing cancellation and a dummy value
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return c.session.cancel, false
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}
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}
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// SetReadCallback allows you to specify a function that will be called whenever
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// a packet is received. This should be used if you wish to implement
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// asynchronous patterns for receiving data from the remote node.
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//
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// Note that if a read callback has been supplied, you should no longer attempt
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// to use the synchronous Read function.
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func (c *Conn) SetReadCallback(callback func([]byte)) {
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c.Act(nil, func() {
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c.readCallback = callback
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c._drainReadBuffer()
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})
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}
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func (c *Conn) _drainReadBuffer() {
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if c.readCallback == nil {
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return
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}
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select {
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case bs := <-c.readBuffer:
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c.readCallback(bs)
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c.Act(nil, c._drainReadBuffer) // In case there's more
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default:
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}
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}
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// Called by the session to pass a new message to the Conn
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func (c *Conn) recvMsg(from phony.Actor, msg []byte) {
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c.Act(from, func() {
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if c.readCallback != nil {
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c.readCallback(msg)
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} else {
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select {
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case c.readBuffer <- msg:
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default:
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}
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}
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})
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}
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// Used internally by Read, the caller is responsible for util.PutBytes when they're done.
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func (c *Conn) readNoCopy() ([]byte, error) {
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var cancel util.Cancellation
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var doCancel bool
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phony.Block(c, func() { cancel, doCancel = c._getDeadlineCancellation(c.readDeadline) })
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if doCancel {
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defer cancel.Cancel(nil)
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}
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// Wait for some traffic to come through from the session
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select {
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case <-cancel.Finished():
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if cancel.Error() == util.CancellationTimeoutError {
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return nil, ConnError{errors.New("read timeout"), true, false, false, 0}
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} else {
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return nil, ConnError{errors.New("session closed"), false, false, true, 0}
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}
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case bs := <-c.readBuffer:
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return bs, nil
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}
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}
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// Read allows you to read from the connection in a synchronous fashion. The
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// function will block up until the point that either new data is available, the
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// connection has been closed or the read deadline has been reached. If the
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// function succeeds, the number of bytes read from the connection will be
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// returned. Otherwise, an error condition will be returned.
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//
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// Note that you can also implement asynchronous reads by using SetReadCallback.
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// If you do that, you should no longer attempt to use the Read function.
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func (c *Conn) Read(b []byte) (int, error) {
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bs, err := c.readNoCopy()
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if err != nil {
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return 0, err
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}
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n := len(bs)
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if len(bs) > len(b) {
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n = len(b)
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err = ConnError{errors.New("read buffer too small for entire packet"), false, true, false, 0}
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}
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// Copy results to the output slice and clean up
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copy(b, bs)
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util.PutBytes(bs)
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// Return the number of bytes copied to the slice, along with any error
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return n, err
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}
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func (c *Conn) _write(msg FlowKeyMessage) error {
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if len(msg.Message) > int(c.mtu) {
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return ConnError{errors.New("packet too big"), true, false, false, int(c.mtu)}
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}
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c.session.Act(c, func() {
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// Send the packet
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c.session._send(msg)
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// Session keep-alive, while we wait for the crypto workers from send
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switch {
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case time.Since(c.session.time) > 6*time.Second:
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if c.session.time.Before(c.session.pingTime) && time.Since(c.session.pingTime) > 6*time.Second {
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// TODO double check that the above condition is correct
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c.doSearch()
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} else {
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c.session.ping(c.session) // TODO send from self if this becomes an actor
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}
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case c.session.reset && c.session.pingTime.Before(c.session.time):
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c.session.ping(c.session) // TODO send from self if this becomes an actor
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default: // Don't do anything, to keep traffic throttled
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}
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})
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return nil
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}
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// WriteFrom should be called by a phony.Actor, and tells the Conn to send a
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// message. This is used internally by Write. If the callback is called with a
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// non-nil value, then it is safe to reuse the argument FlowKeyMessage.
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func (c *Conn) WriteFrom(from phony.Actor, msg FlowKeyMessage, callback func(error)) {
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c.Act(from, func() {
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callback(c._write(msg))
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})
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}
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// writeNoCopy is used internally by Write and makes use of WriteFrom under the hood.
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// The caller must not reuse the argument FlowKeyMessage when a nil error is returned.
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func (c *Conn) writeNoCopy(msg FlowKeyMessage) error {
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var cancel util.Cancellation
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var doCancel bool
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phony.Block(c, func() { cancel, doCancel = c._getDeadlineCancellation(c.writeDeadline) })
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if doCancel {
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defer cancel.Cancel(nil)
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}
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var err error
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select {
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case <-cancel.Finished():
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if cancel.Error() == util.CancellationTimeoutError {
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err = ConnError{errors.New("write timeout"), true, false, false, 0}
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} else {
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err = ConnError{errors.New("session closed"), false, false, true, 0}
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}
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default:
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done := make(chan struct{})
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callback := func(e error) { err = e; close(done) }
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c.WriteFrom(nil, msg, callback)
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<-done
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}
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return err
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}
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// Write allows you to write to the connection in a synchronous fashion. This
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// function may block until either the write has completed, the connection has
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// been closed or the write deadline has been reached. If the function succeeds,
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// the number of written bytes is returned. Otherwise, an error condition is
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// returned.
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func (c *Conn) Write(b []byte) (int, error) {
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written := len(b)
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msg := FlowKeyMessage{Message: append(util.GetBytes(), b...)}
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err := c.writeNoCopy(msg)
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if err != nil {
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util.PutBytes(msg.Message)
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written = 0
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}
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return written, err
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}
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// Close will close an open connection and any blocking operations on the
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// connection will unblock and return. From this point forward, the connection
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// can no longer be used and you should no longer attempt to Read or Write to
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// the connection.
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func (c *Conn) Close() (err error) {
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phony.Block(c, func() {
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if c.session != nil {
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// Close the session, if it hasn't been closed already
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if e := c.session.cancel.Cancel(errors.New("connection closed")); e != nil {
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err = ConnError{errors.New("close failed, session already closed"), false, false, true, 0}
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} else {
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c.session.doRemove()
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}
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}
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})
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return
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}
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// LocalAddr returns the complete public key of the local side of the
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// connection. This is always going to return your own node's public key.
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func (c *Conn) LocalAddr() net.Addr {
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return &c.core.boxPub
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}
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// RemoteAddr returns the complete public key of the remote side of the
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// connection.
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func (c *Conn) RemoteAddr() net.Addr {
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if c.session != nil {
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return &c.session.theirPermPub
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}
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return nil
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}
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// SetDeadline is equivalent to calling both SetReadDeadline and
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// SetWriteDeadline with the same value, configuring the maximum amount of time
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// that synchronous Read and Write operations can block for. If no deadline is
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// configured, Read and Write operations can potentially block indefinitely.
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func (c *Conn) SetDeadline(t time.Time) error {
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c.SetReadDeadline(t)
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c.SetWriteDeadline(t)
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return nil
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}
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// SetReadDeadline configures the maximum amount of time that a synchronous Read
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// operation can block for. A Read operation will unblock at the point that the
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// read deadline is reached if no other condition (such as data arrival or
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// connection closure) happens first. If no deadline is configured, Read
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// operations can potentially block indefinitely.
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func (c *Conn) SetReadDeadline(t time.Time) error {
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// TODO warn that this can block while waiting for the Conn actor to run, so don't call it from other actors...
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phony.Block(c, func() { c.readDeadline = &t })
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return nil
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}
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// SetWriteDeadline configures the maximum amount of time that a synchronous
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// Write operation can block for. A Write operation will unblock at the point
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// that the read deadline is reached if no other condition (such as data sending
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// or connection closure) happens first. If no deadline is configured, Write
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// operations can potentially block indefinitely.
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func (c *Conn) SetWriteDeadline(t time.Time) error {
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// TODO warn that this can block while waiting for the Conn actor to run, so don't call it from other actors...
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phony.Block(c, func() { c.writeDeadline = &t })
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return nil
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}
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