From 8474eddd3aa7822ac10c5578d6fcc83eca1271a6 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Fri, 9 May 2025 12:24:45 +0800
Subject: [PATCH] use the slices package to simply QUIC version comparisons
 (#5130)

No functional change expected.
---
 connection.go                | 15 +++++++--------
 internal/protocol/version.go | 14 ++++----------
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/connection.go b/connection.go
index 28a2bb46..c6116fa9 100644
--- a/connection.go
+++ b/connection.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"net"
 	"reflect"
+	"slices"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -1278,15 +1279,13 @@ func (s *connection) handleVersionNegotiationPacket(p receivedPacket) {
 		return
 	}
 
-	for _, v := range supportedVersions {
-		if v == s.version {
-			if s.tracer != nil && s.tracer.DroppedPacket != nil {
-				s.tracer.DroppedPacket(logging.PacketTypeVersionNegotiation, protocol.InvalidPacketNumber, p.Size(), logging.PacketDropUnexpectedVersion)
-			}
-			// The Version Negotiation packet contains the version that we offered.
-			// This might be a packet sent by an attacker, or it was corrupted.
-			return
+	if slices.Contains(supportedVersions, s.version) {
+		if s.tracer != nil && s.tracer.DroppedPacket != nil {
+			s.tracer.DroppedPacket(logging.PacketTypeVersionNegotiation, protocol.InvalidPacketNumber, p.Size(), logging.PacketDropUnexpectedVersion)
 		}
+		// The Version Negotiation packet contains the version that we offered.
+		// This might be a packet sent by an attacker, or it was corrupted.
+		return
 	}
 
 	s.logger.Infof("Received a Version Negotiation packet. Supported Versions: %s", supportedVersions)
diff --git a/internal/protocol/version.go b/internal/protocol/version.go
index 646587f3..c9254a04 100644
--- a/internal/protocol/version.go
+++ b/internal/protocol/version.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"math"
 	mrand "math/rand/v2"
+	"slices"
 	"sync"
 )
 
@@ -64,12 +65,7 @@ func (vn Version) toGQUICVersion() int {
 
 // IsSupportedVersion returns true if the server supports this version
 func IsSupportedVersion(supported []Version, v Version) bool {
-	for _, t := range supported {
-		if t == v {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(supported, v)
 }
 
 // ChooseSupportedVersion finds the best version in the overlap of ours and theirs
@@ -78,10 +74,8 @@ func IsSupportedVersion(supported []Version, v Version) bool {
 // The bool returned indicates if a matching version was found.
 func ChooseSupportedVersion(ours, theirs []Version) (Version, bool) {
 	for _, ourVer := range ours {
-		for _, theirVer := range theirs {
-			if ourVer == theirVer {
-				return ourVer, true
-			}
+		if slices.Contains(theirs, ourVer) {
+			return ourVer, true
 		}
 	}
 	return 0, false