From db9b3fed9a2aab0626335548887d328f46db0895 Mon Sep 17 00:00:00 2001
From: tsosunchia <59512455+tsosunchia@users.noreply.github.com>
Date: Thu, 5 Oct 2023 04:30:09 +0800
Subject: [PATCH] =?UTF-8?q?=E5=B7=B2=E7=BB=8F=E5=8F=AF=E4=BB=A5=E6=A3=80?=
 =?UTF-8?q?=E6=B5=8B=E5=88=B0MPLS?=
MIME-Version: 1.0
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---
 trace/icmp_ipv4.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/trace/icmp_ipv4.go b/trace/icmp_ipv4.go
index 901457c..f7c80eb 100644
--- a/trace/icmp_ipv4.go
+++ b/trace/icmp_ipv4.go
@@ -175,6 +175,28 @@ func (t *ICMPTracer) listenICMP() {
 func (t *ICMPTracer) handleICMPMessage(msg ReceivedMessage, icmpType int8, data []byte, ttl int) {
 	t.inflightRequestRWLock.RLock()
 	defer t.inflightRequestRWLock.RUnlock()
+
+	extensionOffset := 20 + 8 + 52
+
+	if len(data) > extensionOffset {
+		extensionBody := data[extensionOffset:]
+
+		if len(extensionBody) >= 8 && len(extensionBody)%8 == 0 {
+			log.Println("ICMP Multi-Part Extensions detected for TTL:", ttl)
+			//TODO: Parse MPLS extensions
+			//for i := 0; i < len(extensionBody); i += 4 {
+			//	labelData := binary.BigEndian.Uint32(extensionBody[i : i+4])
+			//
+			//	label := (labelData & 0xFFFFF000) >> 12
+			//	tc := (labelData & 0x00000E00) >> 9
+			//	s := (labelData & 0x00000100) >> 8
+			//	mplsTTL := labelData & 0x000000FF
+			//
+			//	log.Printf("MPLS for TTL %d: Lbl %d TC %d S %d TTL %d\n", ttl, label, tc, s, mplsTTL)
+			//}
+		}
+	}
+
 	if _, ok := t.inflightRequest[ttl]; ok {
 		t.inflightRequest[ttl] <- Hop{
 			Success: true,