device: remove recursion from insertion and connect parent pointers
This makes the insertion algorithm a bit more efficient, while also now taking on the additional task of connecting up parent pointers. This will be handy in the following commit. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld
parent
4a57024b94
commit
b41f4cc768
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@ -14,9 +14,15 @@ import (
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"unsafe"
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)
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type parentIndirection struct {
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parentBit **trieEntry
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parentBitType uint8
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}
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type trieEntry struct {
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peer *Peer
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child [2]*trieEntry
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parent parentIndirection
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cidr uint8
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bitAtByte uint8
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bitAtShift uint8
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@ -114,43 +120,45 @@ func (node *trieEntry) maskSelf() {
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}
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}
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func (node *trieEntry) insert(ip net.IP, cidr uint8, peer *Peer) *trieEntry {
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func (node *trieEntry) nodePlacement(ip net.IP, cidr uint8) (parent *trieEntry, exact bool) {
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for node != nil && node.cidr <= cidr && commonBits(node.bits, ip) >= node.cidr {
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parent = node
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if parent.cidr == cidr {
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exact = true
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return
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}
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bit := node.choose(ip)
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node = node.child[bit]
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}
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return
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}
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// at leaf
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if node == nil {
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func (trie parentIndirection) insert(ip net.IP, cidr uint8, peer *Peer) {
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if *trie.parentBit == nil {
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node := &trieEntry{
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bits: ip,
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peer: peer,
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parent: trie,
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bits: ip,
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cidr: cidr,
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bitAtByte: cidr / 8,
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bitAtShift: 7 - (cidr % 8),
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}
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node.maskSelf()
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node.addToPeerEntries()
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return node
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*trie.parentBit = node
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return
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}
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// traverse deeper
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common := commonBits(node.bits, ip)
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if node.cidr <= cidr && common >= node.cidr {
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if node.cidr == cidr {
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node, exact := (*trie.parentBit).nodePlacement(ip, cidr)
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if exact {
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node.removeFromPeerEntries()
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node.peer = peer
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node.addToPeerEntries()
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return node
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return
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}
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bit := node.choose(ip)
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node.child[bit] = node.child[bit].insert(ip, cidr, peer)
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return node
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}
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// split node
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newNode := &trieEntry{
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bits: ip,
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peer: peer,
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bits: ip,
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cidr: cidr,
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bitAtByte: cidr / 8,
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bitAtShift: 7 - (cidr % 8),
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@ -158,34 +166,61 @@ func (node *trieEntry) insert(ip net.IP, cidr uint8, peer *Peer) *trieEntry {
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newNode.maskSelf()
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newNode.addToPeerEntries()
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var down *trieEntry
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if node == nil {
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down = *trie.parentBit
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} else {
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bit := node.choose(ip)
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down = node.child[bit]
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if down == nil {
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newNode.parent = parentIndirection{&node.child[bit], bit}
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node.child[bit] = newNode
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return
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}
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}
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common := commonBits(down.bits, ip)
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if common < cidr {
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cidr = common
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}
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// check for shorter prefix
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parent := node
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if newNode.cidr == cidr {
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bit := newNode.choose(node.bits)
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newNode.child[bit] = node
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return newNode
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bit := newNode.choose(down.bits)
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down.parent = parentIndirection{&newNode.child[bit], bit}
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newNode.child[bit] = down
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if parent == nil {
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newNode.parent = trie
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*trie.parentBit = newNode
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} else {
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bit := parent.choose(newNode.bits)
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newNode.parent = parentIndirection{&parent.child[bit], bit}
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parent.child[bit] = newNode
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}
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return
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}
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// create new parent for node & newNode
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parent := &trieEntry{
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bits: append([]byte{}, ip...),
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peer: nil,
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node = &trieEntry{
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bits: append([]byte{}, newNode.bits...),
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cidr: cidr,
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bitAtByte: cidr / 8,
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bitAtShift: 7 - (cidr % 8),
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}
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parent.maskSelf()
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node.maskSelf()
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bit := parent.choose(ip)
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parent.child[bit] = newNode
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parent.child[bit^1] = node
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return parent
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bit := node.choose(down.bits)
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down.parent = parentIndirection{&node.child[bit], bit}
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node.child[bit] = down
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bit = node.choose(newNode.bits)
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newNode.parent = parentIndirection{&node.child[bit], bit}
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node.child[bit] = newNode
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if parent == nil {
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node.parent = trie
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*trie.parentBit = node
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} else {
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bit := parent.choose(node.bits)
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node.parent = parentIndirection{&parent.child[bit], bit}
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parent.child[bit] = node
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}
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}
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func (node *trieEntry) lookup(ip net.IP) *Peer {
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@ -236,9 +271,9 @@ func (table *AllowedIPs) Insert(ip net.IP, cidr uint8, peer *Peer) {
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switch len(ip) {
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case net.IPv6len:
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table.IPv6 = table.IPv6.insert(ip, cidr, peer)
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parentIndirection{&table.IPv6, 2}.insert(ip, cidr, peer)
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case net.IPv4len:
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table.IPv4 = table.IPv4.insert(ip, cidr, peer)
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parentIndirection{&table.IPv4, 2}.insert(ip, cidr, peer)
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default:
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panic(errors.New("inserting unknown address type"))
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}
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@ -65,9 +65,9 @@ func (r SlowRouter) Lookup(addr []byte) *Peer {
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}
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func TestTrieRandomIPv4(t *testing.T) {
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var trie *trieEntry
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var slow SlowRouter
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var peers []*Peer
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var allowedIPs AllowedIPs
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rand.Seed(1)
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@ -82,7 +82,7 @@ func TestTrieRandomIPv4(t *testing.T) {
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rand.Read(addr[:])
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cidr := uint8(rand.Uint32() % (AddressLength * 8))
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index := rand.Int() % NumberOfPeers
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trie = trie.insert(addr[:], cidr, peers[index])
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allowedIPs.Insert(addr[:], cidr, peers[index])
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slow = slow.Insert(addr[:], cidr, peers[index])
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}
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@ -90,7 +90,7 @@ func TestTrieRandomIPv4(t *testing.T) {
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var addr [AddressLength]byte
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rand.Read(addr[:])
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peer1 := slow.Lookup(addr[:])
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peer2 := trie.lookup(addr[:])
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peer2 := allowedIPs.LookupIPv4(addr[:])
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if peer1 != peer2 {
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t.Error("Trie did not match naive implementation, for:", addr)
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}
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@ -98,9 +98,9 @@ func TestTrieRandomIPv4(t *testing.T) {
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}
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func TestTrieRandomIPv6(t *testing.T) {
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var trie *trieEntry
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var slow SlowRouter
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var peers []*Peer
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var allowedIPs AllowedIPs
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rand.Seed(1)
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@ -115,7 +115,7 @@ func TestTrieRandomIPv6(t *testing.T) {
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rand.Read(addr[:])
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cidr := uint8(rand.Uint32() % (AddressLength * 8))
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index := rand.Int() % NumberOfPeers
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trie = trie.insert(addr[:], cidr, peers[index])
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allowedIPs.Insert(addr[:], cidr, peers[index])
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slow = slow.Insert(addr[:], cidr, peers[index])
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}
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@ -123,7 +123,7 @@ func TestTrieRandomIPv6(t *testing.T) {
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var addr [AddressLength]byte
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rand.Read(addr[:])
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peer1 := slow.Lookup(addr[:])
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peer2 := trie.lookup(addr[:])
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peer2 := allowedIPs.LookupIPv6(addr[:])
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if peer1 != peer2 {
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t.Error("Trie did not match naive implementation, for:", addr)
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}
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@ -42,6 +42,7 @@ func TestCommonBits(t *testing.T) {
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func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *testing.B) {
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var trie *trieEntry
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var peers []*Peer
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root := parentIndirection{&trie, 2}
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rand.Seed(1)
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@ -56,7 +57,7 @@ func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *test
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rand.Read(addr[:])
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cidr := uint8(rand.Uint32() % (AddressLength * 8))
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index := rand.Int() % peerNumber
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trie = trie.insert(addr[:], cidr, peers[index])
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root.insert(addr[:], cidr, peers[index])
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}
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for n := 0; n < b.N; n++ {
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@ -94,21 +95,21 @@ func TestTrieIPv4(t *testing.T) {
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g := &Peer{}
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h := &Peer{}
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var trie *trieEntry
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var allowedIPs AllowedIPs
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insert := func(peer *Peer, a, b, c, d byte, cidr uint8) {
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trie = trie.insert([]byte{a, b, c, d}, cidr, peer)
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allowedIPs.Insert([]byte{a, b, c, d}, cidr, peer)
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}
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assertEQ := func(peer *Peer, a, b, c, d byte) {
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p := trie.lookup([]byte{a, b, c, d})
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p := allowedIPs.LookupIPv4([]byte{a, b, c, d})
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if p != peer {
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t.Error("Assert EQ failed")
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}
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}
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assertNEQ := func(peer *Peer, a, b, c, d byte) {
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p := trie.lookup([]byte{a, b, c, d})
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p := allowedIPs.LookupIPv4([]byte{a, b, c, d})
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if p == peer {
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t.Error("Assert NEQ failed")
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}
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@ -150,7 +151,7 @@ func TestTrieIPv4(t *testing.T) {
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assertEQ(a, 192, 0, 0, 0)
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assertEQ(a, 255, 0, 0, 0)
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trie = trie.removeByPeer(a)
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allowedIPs.RemoveByPeer(a)
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assertNEQ(a, 1, 0, 0, 0)
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assertNEQ(a, 64, 0, 0, 0)
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@ -158,12 +159,12 @@ func TestTrieIPv4(t *testing.T) {
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assertNEQ(a, 192, 0, 0, 0)
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assertNEQ(a, 255, 0, 0, 0)
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trie = nil
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allowedIPs = AllowedIPs{}
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insert(a, 192, 168, 0, 0, 16)
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insert(a, 192, 168, 0, 0, 24)
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trie = trie.removeByPeer(a)
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allowedIPs.RemoveByPeer(a)
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assertNEQ(a, 192, 168, 0, 1)
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}
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@ -181,7 +182,7 @@ func TestTrieIPv6(t *testing.T) {
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g := &Peer{}
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h := &Peer{}
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var trie *trieEntry
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var allowedIPs AllowedIPs
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expand := func(a uint32) []byte {
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var out [4]byte
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@ -198,7 +199,7 @@ func TestTrieIPv6(t *testing.T) {
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addr = append(addr, expand(b)...)
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addr = append(addr, expand(c)...)
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addr = append(addr, expand(d)...)
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trie = trie.insert(addr, cidr, peer)
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allowedIPs.Insert(addr, cidr, peer)
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}
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assertEQ := func(peer *Peer, a, b, c, d uint32) {
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@ -207,7 +208,7 @@ func TestTrieIPv6(t *testing.T) {
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addr = append(addr, expand(b)...)
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addr = append(addr, expand(c)...)
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addr = append(addr, expand(d)...)
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p := trie.lookup(addr)
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p := allowedIPs.LookupIPv6(addr)
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if p != peer {
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t.Error("Assert EQ failed")
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}
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