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make Dial block until the search finishes, and use it as such

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This commit is contained in:
Arceliar 2019-06-28 18:42:31 -05:00
parent 29a0f8b572
commit 5df110ac79
5 changed files with 111 additions and 156 deletions
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55
src/tuntap/iface.go
View File

@ -134,7 +134,7 @@ func (tun *TunAdapter) reader() error {
}
// Then offset the buffer so that we can now just treat it as an IP
// packet from now on
bs = bs[offset:]
bs = bs[offset:] // FIXME this breaks bs for the next read and means n is the wrong value
}
// From the IP header, work out what our source and destination addresses
// and node IDs are. We will need these in order to work out where to send
@ -225,21 +225,46 @@ func (tun *TunAdapter) reader() error {
panic("Given empty dstNodeID and dstNodeIDMask - this shouldn't happen")
}
// Dial to the remote node
if conn, err := tun.dialer.DialByNodeIDandMask(dstNodeID, dstNodeIDMask); err == nil {
// We've been given a connection so prepare the session wrapper
if s, err := tun.wrap(conn); err != nil {
// Something went wrong when storing the connection, typically that
// something already exists for this address or subnet
tun.log.Debugln("TUN/TAP iface wrap:", err)
} else {
// Update our reference to the connection
session, isIn = s, true
go func() {
// FIXME just spitting out a goroutine to do this is kind of ugly and means we drop packets until the dial finishes
tun.mutex.Lock()
_, known := tun.dials[*dstNodeID]
packet := append(util.GetBytes(), bs[:n]...)
tun.dials[*dstNodeID] = append(tun.dials[*dstNodeID], packet)
for len(tun.dials[*dstNodeID]) > 32 {
util.PutBytes(tun.dials[*dstNodeID][0])
tun.dials[*dstNodeID] = tun.dials[*dstNodeID][1:]
}
} else {
// We weren't able to dial for some reason so there's no point in
// continuing this iteration - skip to the next one
continue
}
tun.mutex.Unlock()
if known {
return
}
var tc *tunConn
if conn, err := tun.dialer.DialByNodeIDandMask(dstNodeID, dstNodeIDMask); err == nil {
// We've been given a connection so prepare the session wrapper
if tc, err = tun.wrap(conn); err != nil {
// Something went wrong when storing the connection, typically that
// something already exists for this address or subnet
tun.log.Debugln("TUN/TAP iface wrap:", err)
}
}
tun.mutex.Lock()
packets := tun.dials[*dstNodeID]
delete(tun.dials, *dstNodeID)
tun.mutex.Unlock()
if tc != nil {
for _, packet := range packets {
select {
case tc.send <- packet:
default:
util.PutBytes(packet)
}
}
}
}()
// While the dial is going on we can't do much else
// continuing this iteration - skip to the next one
continue
}
// If we have a connection now, try writing to it
if isIn && session != nil {

2
src/tuntap/tun.go
View File

@ -49,6 +49,7 @@ type TunAdapter struct {
mutex sync.RWMutex // Protects the below
addrToConn map[address.Address]*tunConn
subnetToConn map[address.Subnet]*tunConn
dials map[crypto.NodeID][][]byte // Buffer of packets to send after dialing finishes
isOpen bool
}
@ -113,6 +114,7 @@ func (tun *TunAdapter) Init(config *config.NodeState, log *log.Logger, listener
tun.dialer = dialer
tun.addrToConn = make(map[address.Address]*tunConn)
tun.subnetToConn = make(map[address.Subnet]*tunConn)
tun.dials = make(map[crypto.NodeID][][]byte)
}
// Start the setup process for the TUN/TAP adapter. If successful, starts the

199
src/yggdrasil/conn.go
View File

@ -45,23 +45,18 @@ type Conn struct {
mutex sync.RWMutex
closed bool
session *sessionInfo
readDeadline atomic.Value // time.Time // TODO timer
writeDeadline atomic.Value // time.Time // TODO timer
searching atomic.Value // bool
searchwait chan struct{} // Never reset this, it's only used for the initial search
writebuf [][]byte // Packets to be sent if/when the search finishes
readDeadline atomic.Value // time.Time // TODO timer
writeDeadline atomic.Value // time.Time // TODO timer
}
// 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,
searchwait: make(chan struct{}),
core: core,
nodeID: nodeID,
nodeMask: nodeMask,
session: session,
}
conn.searching.Store(false)
return &conn
}
@ -69,91 +64,38 @@ func (c *Conn) String() string {
return fmt.Sprintf("conn=%p", c)
}
// This method should only be called from the router goroutine
func (c *Conn) startSearch() {
// The searchCompleted callback is given to the search
searchCompleted := func(sinfo *sessionInfo, err error) {
defer c.searching.Store(false)
// If the search failed for some reason, e.g. it hit a dead end or timed
// out, then do nothing
if err != nil {
c.core.log.Debugln(c.String(), "DHT search failed:", err)
return
}
// Take the connection mutex
c.mutex.Lock()
defer c.mutex.Unlock()
// Were we successfully given a sessionInfo pointer?
if sinfo != nil {
// Store it, and update the nodeID and nodeMask (which may have been
// wildcarded before now) with their complete counterparts
c.core.log.Debugln(c.String(), "DHT search completed")
c.session = sinfo
c.nodeID = crypto.GetNodeID(&sinfo.theirPermPub)
for i := range c.nodeMask {
c.nodeMask[i] = 0xFF
// This should only be called from the router goroutine
func (c *Conn) search() error {
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:
}
// Make sure that any blocks on read/write operations are lifted
defer func() { recover() }() // So duplicate searches don't panic
close(c.searchwait)
} else {
// No session was returned - this shouldn't really happen because we
// should always return an error reason if we don't return a session
panic("DHT search didn't return an error or a sessionInfo")
}
if c.closed {
// Things were closed before the search returned
// Go ahead and close it again to make sure the session is cleaned up
go c.Close()
} else {
// Send any messages we may have buffered
var msgs [][]byte
msgs, c.writebuf = c.writebuf, nil
go func() {
for _, msg := range msgs {
c.Write(msg)
util.PutBytes(msg)
}
}()
}
}
// doSearch will be called below in response to one or more conditions
doSearch := func() {
c.searching.Store(true)
// 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
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 = c.core.searches.newIterSearch(c.nodeID, c.nodeMask, searchCompleted)
sinfo.continueSearch()
}
// Take a copy of the session object, in case it changes later
c.mutex.RLock()
sinfo := c.session
c.mutex.RUnlock()
if c.session == nil {
// No session object is present so previous searches, if we ran any, have
// not yielded a useful result (dead end, remote host not found)
doSearch()
} else {
sinfo.worker <- func() {
switch {
case !sinfo.init:
doSearch()
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
doSearch()
} else {
c.core.sessions.ping(sinfo)
}
default: // Don't do anything, to keep traffic throttled
}
<-done
c.session = sess
if c.session == nil && err == nil {
panic("search failed but returend no error")
}
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
}
func getDeadlineTimer(value *atomic.Value) *time.Timer {
@ -167,30 +109,9 @@ func getDeadlineTimer(value *atomic.Value) *time.Timer {
func (c *Conn) Read(b []byte) (int, error) {
// Take a copy of the session object
c.mutex.RLock()
sinfo := c.session
c.mutex.RUnlock()
timer := getDeadlineTimer(&c.readDeadline)
defer util.TimerStop(timer)
// If there is a search in progress then wait for the result
if sinfo == nil {
// Wait for the search to complete
select {
case <-c.searchwait:
case <-timer.C:
return 0, ConnError{errors.New("timeout"), true, false, 0}
}
// Retrieve our session info again
c.mutex.RLock()
sinfo = c.session
c.mutex.RUnlock()
// If sinfo is still nil at this point then the search failed and the
// searchwait channel has been recreated, so might as well give up and
// return an error code
if sinfo == nil {
return 0, errors.New("search failed")
}
}
for {
// Wait for some traffic to come through from the session
select {
@ -253,32 +174,7 @@ func (c *Conn) Read(b []byte) (int, error) {
}
func (c *Conn) Write(b []byte) (bytesWritten int, err error) {
c.mutex.RLock()
sinfo := c.session
c.mutex.RUnlock()
// If the session doesn't exist, or isn't initialised (which probably means
// that the search didn't complete successfully) then we may need to wait for
// the search to complete or start the search again
if sinfo == nil || !sinfo.init {
// Is a search already taking place?
if searching, sok := c.searching.Load().(bool); !sok || (sok && !searching) {
// No search was already taking place so start a new one
c.core.router.doAdmin(c.startSearch)
}
// Buffer the packet to be sent if/when the search is finished
c.mutex.Lock()
defer c.mutex.Unlock()
c.writebuf = append(c.writebuf, append(util.GetBytes(), b...))
for len(c.writebuf) > 32 {
util.PutBytes(c.writebuf[0])
c.writebuf = c.writebuf[1:]
}
return len(b), nil
} else {
// This triggers some session keepalive traffic
// FIXME this desparately needs to be refactored, since the ping case needlessly goes through the router goroutine just to have it pass a function to the session worker when it determines that a session already exists.
c.core.router.doAdmin(c.startSearch)
}
var packet []byte
done := make(chan struct{})
written := len(b)
@ -301,6 +197,34 @@ func (c *Conn) Write(b []byte) (bytesWritten int, err error) {
}
packet = p.encode()
sinfo.bytesSent += uint64(len(b))
// The rest of this work is session keep-alive traffic
doSearch := func() {
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 }()
}
switch {
case !sinfo.init:
doSearch()
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
doSearch()
} else {
sinfo.core.sessions.ping(sinfo)
}
default: // Don't do anything, to keep traffic throttled
}
}
// Set up a timer so this doesn't block forever
timer := getDeadlineTimer(&c.writeDeadline)
@ -327,7 +251,6 @@ func (c *Conn) Close() error {
if c.session != nil {
// Close the session, if it hasn't been closed already
c.session.close()
c.session = nil
}
// This can't fail yet - TODO?
c.closed = true

5
src/yggdrasil/dialer.go
View File

@ -14,6 +14,8 @@ type Dialer struct {
core *Core
}
// TODO DialContext that allows timeouts/cancellation, Dial should just call this with no timeout set in the context
// Dial opens a session to the given node. The first paramter should be "nodeid"
// and the second parameter should contain a hexadecimal representation of the
// target node ID.
@ -58,5 +60,8 @@ func (d *Dialer) Dial(network, address string) (*Conn, error) {
// NodeID parameters.
func (d *Dialer) DialByNodeIDandMask(nodeID, nodeMask *crypto.NodeID) (*Conn, error) {
conn := newConn(d.core, nodeID, nodeMask, nil)
if err := conn.search(); err != nil {
return nil, err
}
return conn, nil
}

6
src/yggdrasil/search.go
View File

@ -141,7 +141,7 @@ func (sinfo *searchInfo) doSearchStep() {
if len(sinfo.toVisit) == 0 {
// Dead end, do cleanup
delete(sinfo.core.searches.searches, sinfo.dest)
go sinfo.callback(nil, errors.New("search reached dead end"))
sinfo.callback(nil, errors.New("search reached dead end"))
return
}
// Send to the next search target
@ -205,7 +205,7 @@ func (sinfo *searchInfo) checkDHTRes(res *dhtRes) bool {
sess = sinfo.core.sessions.createSession(&res.Key)
if sess == nil {
// nil if the DHT search finished but the session wasn't allowed
go sinfo.callback(nil, errors.New("session not allowed"))
sinfo.callback(nil, errors.New("session not allowed"))
return true
}
_, isIn := sinfo.core.sessions.getByTheirPerm(&res.Key)
@ -217,7 +217,7 @@ func (sinfo *searchInfo) checkDHTRes(res *dhtRes) bool {
sess.coords = res.Coords
sess.packet = sinfo.packet
sinfo.core.sessions.ping(sess)
go sinfo.callback(sess, nil)
sinfo.callback(sess, nil)
// Cleanup
delete(sinfo.core.searches.searches, res.Dest)
return true