From 02a125bb86329726525c0dca8a9aa2976b298d42 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=2E=20Mert=20Y=C4=B1ld=C4=B1ran?= <mehmet@up9.com>
Date: Mon, 22 Nov 2021 17:35:17 +0300
Subject: [PATCH] Disable IPv4 defragmentation and support IPv6 (#487)

* Remove the extra negation on `nodefrag` flag's value

* Support IPv4 fragmentation and IPv6 at the same time

* Re-enable `nodefrag` flag
---
 shared/kubernetes/provider.go   |  9 +++----
 tap/source/tcp_packet_source.go | 42 ++++++++++++++++-----------------
 2 files changed, 25 insertions(+), 26 deletions(-)

diff --git a/shared/kubernetes/provider.go b/shared/kubernetes/provider.go
index 0c024ab47..0f0feabdb 100644
--- a/shared/kubernetes/provider.go
+++ b/shared/kubernetes/provider.go
@@ -6,12 +6,16 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
+	"net/url"
+	"path/filepath"
+	"regexp"
+
 	"github.com/op/go-logging"
 	"github.com/up9inc/mizu/shared"
 	"github.com/up9inc/mizu/shared/logger"
 	"github.com/up9inc/mizu/shared/semver"
 	"github.com/up9inc/mizu/tap/api"
-	"io"
 	v1 "k8s.io/api/apps/v1"
 	core "k8s.io/api/core/v1"
 	rbac "k8s.io/api/rbac/v1"
@@ -32,9 +36,6 @@ import (
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/clientcmd"
 	watchtools "k8s.io/client-go/tools/watch"
-	"net/url"
-	"path/filepath"
-	"regexp"
 )
 
 type Provider struct {
diff --git a/tap/source/tcp_packet_source.go b/tap/source/tcp_packet_source.go
index 2ad468b38..a7c0258ad 100644
--- a/tap/source/tcp_packet_source.go
+++ b/tap/source/tcp_packet_source.go
@@ -121,29 +121,27 @@ func (source *tcpPacketSource) readPackets(ipdefrag bool, packets chan<- TcpPack
 		}
 
 		// defrag the IPv4 packet if required
-		if !ipdefrag {
-			ip4Layer := packet.Layer(layers.LayerTypeIPv4)
-			if ip4Layer == nil {
-				continue
-			}
-			ip4 := ip4Layer.(*layers.IPv4)
-			l := ip4.Length
-			newip4, err := source.defragger.DefragIPv4(ip4)
-			if err != nil {
-				logger.Log.Fatal("Error while de-fragmenting", err)
-			} else if newip4 == nil {
-				logger.Log.Debugf("Fragment...")
-				continue // packet fragment, we don't have whole packet yet.
-			}
-			if newip4.Length != l {
-				diagnose.InternalStats.Ipdefrag++
-				logger.Log.Debugf("Decoding re-assembled packet: %s", newip4.NextLayerType())
-				pb, ok := packet.(gopacket.PacketBuilder)
-				if !ok {
-					logger.Log.Panic("Not a PacketBuilder")
+		if ipdefrag {
+			if ip4Layer := packet.Layer(layers.LayerTypeIPv4); ip4Layer != nil {
+				ip4 := ip4Layer.(*layers.IPv4)
+				l := ip4.Length
+				newip4, err := source.defragger.DefragIPv4(ip4)
+				if err != nil {
+					logger.Log.Fatal("Error while de-fragmenting", err)
+				} else if newip4 == nil {
+					logger.Log.Debugf("Fragment...")
+					continue // packet fragment, we don't have whole packet yet.
+				}
+				if newip4.Length != l {
+					diagnose.InternalStats.Ipdefrag++
+					logger.Log.Debugf("Decoding re-assembled packet: %s", newip4.NextLayerType())
+					pb, ok := packet.(gopacket.PacketBuilder)
+					if !ok {
+						logger.Log.Panic("Not a PacketBuilder")
+					}
+					nextDecoder := newip4.NextLayerType()
+					_ = nextDecoder.Decode(newip4.Payload, pb)
 				}
-				nextDecoder := newip4.NextLayerType()
-				_ = nextDecoder.Decode(newip4.Payload, pb)
 			}
 		}