1 files changed, 0 insertions, 147 deletions
diff --git a/common/replayfilter/replay_filter.go b/common/replayfilter/replay_filter.go
deleted file mode 100644
index 5513361..0000000
--- a/common/replayfilter/replay_filter.go
+++ /dev/null
@@ -1,147 +0,0 @@
-/*
- * Copyright (c) 2014, Yawning Angel <yawning at torproject dot org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- *  * Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- *
- *  * Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- */
-
-// Package replayfilter implements a generic replay detection filter with a
-// caller specifiable time-to-live.  It only detects if a given byte sequence
-// has been seen before based on the SipHash-2-4 digest of the sequence.
-// Collisions are treated as positive matches, though the probability of this
-// happening is negligible.
-package replayfilter
-
-import (
-	"container/list"
-	"encoding/binary"
-	"sync"
-	"time"
-
-	"github.com/dchest/siphash"
-
-	"github.com/OperatorFoundation/obfs4/common/csrand"
-)
-
-// maxFilterSize is the maximum capacity of a replay filter.  This value is
-// more as a safeguard to prevent runaway filter growth, and is sized to be
-// serveral orders of magnitude greater than the number of connections a busy
-// bridge sees in one day, so in practice should never be reached.
-const maxFilterSize = 100 * 1024
-
-type entry struct {
-	digest    uint64
-	firstSeen time.Time
-	element   *list.Element
-}
-
-// ReplayFilter is a simple filter designed only to detect if a given byte
-// sequence has been seen before.
-type ReplayFilter struct {
-	sync.Mutex
-
-	filter map[uint64]*entry
-	fifo   *list.List
-
-	key [2]uint64
-	ttl time.Duration
-}
-
-// New creates a new ReplayFilter instance.
-func New(ttl time.Duration) (filter *ReplayFilter, err error) {
-	// Initialize the SipHash-2-4 instance with a random key.
-	var key [16]byte
-	if err = csrand.Bytes(key[:]); err != nil {
-		return
-	}
-
-	filter = new(ReplayFilter)
-	filter.filter = make(map[uint64]*entry)
-	filter.fifo = list.New()
-	filter.key[0] = binary.BigEndian.Uint64(key[0:8])
-	filter.key[1] = binary.BigEndian.Uint64(key[8:16])
-	filter.ttl = ttl
-
-	return
-}
-
-// TestAndSet queries the filter for a given byte sequence, inserts the
-// sequence, and returns if it was present before the insertion operation.
-func (f *ReplayFilter) TestAndSet(now time.Time, buf []byte) bool {
-	digest := siphash.Hash(f.key[0], f.key[1], buf)
-
-	f.Lock()
-	defer f.Unlock()
-
-	f.compactFilter(now)
-
-	if e := f.filter[digest]; e != nil {
-		// Hit.  Just return.
-		return true
-	}
-
-	// Miss.  Add a new entry.
-	e := new(entry)
-	e.digest = digest
-	e.firstSeen = now
-	e.element = f.fifo.PushBack(e)
-	f.filter[digest] = e
-
-	return false
-}
-
-func (f *ReplayFilter) compactFilter(now time.Time) {
-	e := f.fifo.Front()
-	for e != nil {
-		ent, _ := e.Value.(*entry)
-
-		// If the filter is not full, only purge entries that exceed the TTL,
-		// otherwise purge at least one entry, then revert to TTL based
-		// compaction.
-		if f.fifo.Len() < maxFilterSize && f.ttl > 0 {
-			deltaT := now.Sub(ent.firstSeen)
-			if deltaT < 0 {
-				// Aeeeeeee, the system time jumped backwards, potentially by
-				// a lot.  This will eventually self-correct, but "eventually"
-				// could be a long time.  As much as this sucks, jettison the
-				// entire filter.
-				f.reset()
-				return
-			} else if deltaT < f.ttl {
-				return
-			}
-		}
-
-		// Remove the eldest entry.
-		eNext := e.Next()
-		delete(f.filter, ent.digest)
-		f.fifo.Remove(ent.element)
-		ent.element = nil
-		e = eNext
-	}
-}
-
-func (f *ReplayFilter) reset() {
-	f.filter = make(map[uint64]*entry)
-	f.fifo = list.New()
-}