From f3147e53e3c6d2e98ace1fd541f637f322d32d53 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Sun, 18 Feb 2024 12:59:42 +1100
Subject: [PATCH] Switch to xxHash for smartban cache

---
 client.go   | 11 +++++++++--
 smartban.go |  3 +--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/client.go b/client.go
index 62c0d2b4..7aab0402 100644
--- a/client.go
+++ b/client.go
@@ -4,12 +4,12 @@ import (
 	"bufio"
 	"context"
 	"crypto/rand"
-	"crypto/sha1"
 	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"expvar"
 	"fmt"
+	"github.com/cespare/xxhash"
 	"io"
 	"math"
 	"net"
@@ -1301,7 +1301,14 @@ func (cl *Client) newTorrentOpt(opts AddTorrentOpts) (t *Torrent) {
 		webSeeds:     make(map[string]*Peer),
 		gotMetainfoC: make(chan struct{}),
 	}
-	t.smartBanCache.Hash = sha1.Sum
+	var salt [8]byte
+	rand.Read(salt[:])
+	t.smartBanCache.Hash = func(b []byte) uint64 {
+		h := xxhash.New()
+		h.Write(salt[:])
+		h.Write(b)
+		return h.Sum64()
+	}
 	t.smartBanCache.Init()
 	t.networkingEnabled.Set()
 	t.logger = cl.logger.WithDefaultLevel(log.Debug)
diff --git a/smartban.go b/smartban.go
index 034a702d..5515ded5 100644
--- a/smartban.go
+++ b/smartban.go
@@ -2,7 +2,6 @@ package torrent
 
 import (
 	"bytes"
-	"crypto/sha1"
 	"net/netip"
 
 	g "github.com/anacrolix/generics"
@@ -12,7 +11,7 @@ import (
 
 type bannableAddr = netip.Addr
 
-type smartBanCache = smartban.Cache[bannableAddr, RequestIndex, [sha1.Size]byte]
+type smartBanCache = smartban.Cache[bannableAddr, RequestIndex, uint64]
 
 type blockCheckingWriter struct {
 	cache        *smartBanCache
-- 
2.48.1