make-tcp.py: create a crafted packet with TCP issues

Prompted by https://code.wireshark.org/review/17749

1 files changed, 56 insertions, 0 deletions

diff --git a/crafted-pkt/make-tcp.py b/crafted-pkt/make-tcp.py
new file mode 100755
index 0000000..8f6bb00
--- /dev/null
+++ b/crafted-pkt/make-tcp.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python2
+# Create a crafted TCP stream with errors
+# Usage: make-tcp.py [output.pcap]
+
+import sys
+from scapy.all import *
+
+pkts = []
+def send(data, flags='A'):
+    if pkts:
+        last = pkts[-1][TCP]
+        seqno = last.seq + len(last.payload)
+    else:
+        seqno = 100
+    tcp = TCP(sport=32323, dport=9, flags=flags, seq=seqno)/data
+    pkt = IP(dst='10.0.0.2',src='10.0.0.1') / tcp
+    pkts.append(pkt)
+    return pkt
+
+# data for one side
+lines = [
+    'First\n',
+    'Second\n',
+    'Third\n',
+    'Fourth\n',
+    'Fifth\n',
+    'Sixth\n',
+    'Last\n'
+]
+for line in lines:
+    send(line)
+send('', flags='F')  # FIN
+
+# Errorneous packets
+numbers = [
+    1,
+    1,  # duplicate packet
+    2,
+    4,  # out-of-order (2)
+    3,  # out-of-order (1)
+    5,
+    #6, # missing packet
+    7,
+    0, # FIN (last packet)
+]
+
+# normal packets
+#numbers = range(1, len(pkts)+1)
+
+pkts2 = [pkts[i-1] for i in numbers]
+
+# Show packets and write to file
+for pkt in pkts2:
+    print(pkt.summary())
+if len(sys.argv) > 1:
+    wrpcap(sys.argv[1], pkts2)