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https://github.com/cwinfo/yggdrasil-go.git
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keep track of recent nonces with a heap and a map instead of a fixed-size bitmask
This commit is contained in:
Arceliar
parent
fdac8932a8
commit
03b8af9f1a
@ -6,6 +6,7 @@ package yggdrasil
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import (
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"bytes"
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"container/heap"
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"errors"
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"sync"
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"time"
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@ -15,42 +16,62 @@ import (
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"github.com/yggdrasil-network/yggdrasil-go/src/util"
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)
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// Duration that we keep track of old nonces per session, to allow some out-of-order packet delivery
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const nonceWindow = time.Second
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// A heap of nonces, used with a map[nonce]time to allow out-of-order packets a little time to arrive without rejecting them
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// Less is backwards so the oldest node is the highest priority for Pop
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type nonceHeap []crypto.BoxNonce
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func (h nonceHeap) Len() int { return len(h) }
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func (h nonceHeap) Less(i, j int) bool { return h[i].Minus(&h[j]) > 0 }
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func (h nonceHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
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func (h *nonceHeap) Push(x interface{}) { *h = append(*h, x.(crypto.BoxNonce)) }
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func (h *nonceHeap) Pop() interface{} {
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l := len(*h)
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var n crypto.BoxNonce
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n, *h = (*h)[l-1], (*h)[:l-1]
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return n
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}
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func (h nonceHeap) peek() *crypto.BoxNonce { return &h[len(h)-1] }
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// All the information we know about an active session.
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// This includes coords, permanent and ephemeral keys, handles and nonces, various sorts of timing information for timeout and maintenance, and some metadata for the admin API.
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type sessionInfo struct {
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mutex sync.Mutex // Protects all of the below, use it any time you read/chance the contents of a session
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core *Core //
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reconfigure chan chan error //
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theirAddr address.Address //
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theirSubnet address.Subnet //
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theirPermPub crypto.BoxPubKey //
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theirSesPub crypto.BoxPubKey //
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mySesPub crypto.BoxPubKey //
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mySesPriv crypto.BoxPrivKey //
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sharedSesKey crypto.BoxSharedKey // derived from session keys
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theirHandle crypto.Handle //
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myHandle crypto.Handle //
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theirNonce crypto.BoxNonce //
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theirNonceMask uint64 //
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myNonce crypto.BoxNonce //
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theirMTU uint16 //
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myMTU uint16 //
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wasMTUFixed bool // Was the MTU fixed by a receive error?
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timeOpened time.Time // Time the sessino was opened
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time time.Time // Time we last received a packet
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mtuTime time.Time // time myMTU was last changed
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pingTime time.Time // time the first ping was sent since the last received packet
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pingSend time.Time // time the last ping was sent
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coords []byte // coords of destination
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reset bool // reset if coords change
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tstamp int64 // ATOMIC - tstamp from their last session ping, replay attack mitigation
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bytesSent uint64 // Bytes of real traffic sent in this session
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bytesRecvd uint64 // Bytes of real traffic received in this session
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init chan struct{} // Closed when the first session pong arrives, used to signal that the session is ready for initial use
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cancel util.Cancellation // Used to terminate workers
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fromRouter chan wire_trafficPacket // Received packets go here, to be decrypted by the session
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recv chan []byte // Decrypted packets go here, picked up by the associated Conn
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send chan FlowKeyMessage // Packets with optional flow key go here, to be encrypted and sent
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mutex sync.Mutex // Protects all of the below, use it any time you read/chance the contents of a session
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core *Core //
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reconfigure chan chan error //
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theirAddr address.Address //
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theirSubnet address.Subnet //
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theirPermPub crypto.BoxPubKey //
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theirSesPub crypto.BoxPubKey //
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mySesPub crypto.BoxPubKey //
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mySesPriv crypto.BoxPrivKey //
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sharedSesKey crypto.BoxSharedKey // derived from session keys
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theirHandle crypto.Handle //
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myHandle crypto.Handle //
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theirNonce crypto.BoxNonce //
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theirNonceHeap nonceHeap // priority queue to keep track of the lowest nonce we recently accepted
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theirNonceMap map[crypto.BoxNonce]time.Time // time we added each nonce to the heap
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myNonce crypto.BoxNonce //
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theirMTU uint16 //
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myMTU uint16 //
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wasMTUFixed bool // Was the MTU fixed by a receive error?
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timeOpened time.Time // Time the sessino was opened
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time time.Time // Time we last received a packet
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mtuTime time.Time // time myMTU was last changed
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pingTime time.Time // time the first ping was sent since the last received packet
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pingSend time.Time // time the last ping was sent
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coords []byte // coords of destination
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reset bool // reset if coords change
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tstamp int64 // ATOMIC - tstamp from their last session ping, replay attack mitigation
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bytesSent uint64 // Bytes of real traffic sent in this session
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bytesRecvd uint64 // Bytes of real traffic received in this session
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init chan struct{} // Closed when the first session pong arrives, used to signal that the session is ready for initial use
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cancel util.Cancellation // Used to terminate workers
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fromRouter chan wire_trafficPacket // Received packets go here, to be decrypted by the session
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recv chan []byte // Decrypted packets go here, picked up by the associated Conn
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send chan FlowKeyMessage // Packets with optional flow key go here, to be encrypted and sent
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}
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func (sinfo *sessionInfo) doFunc(f func()) {
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@ -87,7 +108,8 @@ func (s *sessionInfo) update(p *sessionPing) bool {
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s.theirHandle = p.Handle
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s.sharedSesKey = *crypto.GetSharedKey(&s.mySesPriv, &s.theirSesPub)
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s.theirNonce = crypto.BoxNonce{}
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s.theirNonceMask = 0
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s.theirNonceHeap = nil
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s.theirNonceMap = make(map[crypto.BoxNonce]time.Time)
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}
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if p.MTU >= 1280 || p.MTU == 0 {
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s.theirMTU = p.MTU
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@ -400,27 +422,40 @@ func (sinfo *sessionInfo) getMTU() uint16 {
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// Checks if a packet's nonce is recent enough to fall within the window of allowed packets, and not already received.
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func (sinfo *sessionInfo) nonceIsOK(theirNonce *crypto.BoxNonce) bool {
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// The bitmask is to allow for some non-duplicate out-of-order packets
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diff := theirNonce.Minus(&sinfo.theirNonce)
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if diff > 0 {
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if theirNonce.Minus(&sinfo.theirNonce) > 0 {
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// This is newer than the newest nonce we've seen
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return true
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}
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return ^sinfo.theirNonceMask&(0x01<<uint64(-diff)) != 0
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if len(sinfo.theirNonceHeap) > 0 {
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if theirNonce.Minus(sinfo.theirNonceHeap.peek()) > 0 {
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if _, isIn := sinfo.theirNonceMap[*theirNonce]; !isIn {
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// This nonce is recent enough that we keep track of older nonces, but it's not one we've seen yet
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return true
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}
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}
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}
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return false
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}
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// Updates the nonce mask by (possibly) shifting the bitmask and setting the bit corresponding to this nonce to 1, and then updating the most recent nonce
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func (sinfo *sessionInfo) updateNonce(theirNonce *crypto.BoxNonce) {
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// Shift nonce mask if needed
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// Set bit
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diff := theirNonce.Minus(&sinfo.theirNonce)
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if diff > 0 {
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// This nonce is newer, so shift the window before setting the bit, and update theirNonce in the session info.
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sinfo.theirNonceMask <<= uint64(diff)
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sinfo.theirNonceMask &= 0x01
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sinfo.theirNonce = *theirNonce
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} else {
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// This nonce is older, so set the bit but do not shift the window.
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sinfo.theirNonceMask &= 0x01 << uint64(-diff)
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// Start with some cleanup
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for len(sinfo.theirNonceHeap) > 64 {
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if time.Since(sinfo.theirNonceMap[*sinfo.theirNonceHeap.peek()]) < nonceWindow {
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// This nonce is still fairly new, so keep it around
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break
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}
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// TODO? reallocate the map in some cases, to free unused map space?
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delete(sinfo.theirNonceMap, *sinfo.theirNonceHeap.peek())
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heap.Pop(&sinfo.theirNonceHeap)
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}
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if theirNonce.Minus(&sinfo.theirNonce) > 0 {
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// This nonce is the newest we've seen, so make a note of that
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sinfo.theirNonce = *theirNonce
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}
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// Add it to the heap/map so we know not to allow it again
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heap.Push(&sinfo.theirNonceHeap, *theirNonce)
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sinfo.theirNonceMap[*theirNonce] = time.Now()
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}
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// Resets all sessions to an uninitialized state.
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