xref: /openbsd-src/regress/sys/kern/sosplice/scapy/scapy-delay-synack.py (revision 8feac64083c74a2316e2b206bf271dd90e50442a) 
1#!/usr/local/bin/python3
2# send data from client via relay before server handshake is completed
3
4import os
5import sys
6import threading
7from addr import *
8from scapy.all import *
9
10client=os.getpid() & 0xffff
11relay=int(sys.argv[2])
12server=int(sys.argv[1])
13
14class Sniff1(threading.Thread):
15	filter = None
16	captured = None
17	packet = None
18	def __init__(self):
19		# clear packets buffered by scapy bpf
20		sniff(iface=LOCAL_IF, timeout=1)
21		super(Sniff1, self).__init__()
22	def run(self):
23		self.captured = sniff(iface=LOCAL_IF, filter=self.filter,
24		    count=1, timeout=5)
25		if self.captured:
26			self.packet = self.captured[0]
27
28ip=IP(src=FAKE_NET_ADDR, dst=REMOTE_ADDR)
29
30print("Send SYN packet, receive SYN+ACK")
31syn=TCP(sport=client, dport=relay, seq=0, flags='S', window=(2**16)-1)
32synack=sr1(ip/syn, iface=LOCAL_IF, timeout=5)
33
34if synack is None:
35	print("ERROR: No matching SYN+ACK packet received")
36	exit(1)
37
38print("Expect spliced SYN")
39sniffer = Sniff1();
40sniffer.filter = "src %s and dst %s and tcp port %u " \
41    "and tcp[tcpflags] = tcp-syn" % (ip.dst, ip.src, server)
42sniffer.start()
43time.sleep(1)
44
45print("Send ACK packet to finish handshake")
46ack=TCP(sport=synack.dport, dport=synack.sport,
47    seq=1, ack=synack.seq+1,  flags='A')
48send(ip/ack, iface=LOCAL_IF)
49
50sniffer.join(timeout=7)
51spliced_syn = sniffer.packet
52
53if spliced_syn is None:
54	print("ERROR: No spliced SYN packet received")
55	exit(1)
56
57print("Send 10 bytes payload")
58data="0123456789"
59payload=TCP(sport=synack.dport, dport=synack.sport,
60    seq=1, ack=synack.seq+1,  flags='AP')/data
61payload_ack=sr1(ip/payload, iface=LOCAL_IF)
62
63if payload_ack is None:
64	print("ERROR: No payload ACK packet received")
65	exit(1)
66if payload_ack.ack != len(data)+1:
67	print("ERROR: Expected ack %d, got %d in payload ACK" %
68	    (len(data)+1, payload_ack.ack))
69	exit(1)
70
71time.sleep(1)
72
73print("Expect spliced payload")
74sniffer = Sniff1();
75sniffer.filter = "src %s and dst %s and tcp port %u " \
76    "and tcp[tcpflags] = tcp-ack|tcp-push" % (ip.dst, ip.src, server)
77sniffer.start()
78time.sleep(1)
79
80print("Send spliced SYN+ACK packet to finish handshake")
81spliced_synack=TCP(sport=spliced_syn.dport, dport=spliced_syn.sport,
82    seq=0, ack=spliced_syn.seq+1, flags='SA')
83spliced_ack=sr1(ip/spliced_synack, iface=LOCAL_IF)
84
85if spliced_ack is None:
86	print("ERROR: No spliced ACK packet received")
87	exit(1)
88
89sniffer.join(timeout=7)
90spliced_payload = sniffer.packet
91
92if spliced_payload is None:
93	print("ERROR: No spliced payload packet received")
94	exit(1)
95if spliced_payload.seq != spliced_ack.seq:
96	print("ERROR: Expected seq %d, got %d in spliced payload" %
97	    (spliced_ack.seq, spliced_payload.seq))
98	exit(1)
99if spliced_payload.len-20-20 != len(data):
100	print("ERROR: Expected len %d, got %d in spliced payload" %
101	    (len(data), spliced_payload.len-20-20))
102	exit(1)
103
104print("Expect spliced ACK retransmission")
105sniffer = Sniff1();
106sniffer.filter = "src %s and dst %s and tcp port %u " \
107    "and tcp[tcpflags] = tcp-ack" % (ip.dst, ip.src, server)
108sniffer.start()
109time.sleep(1)
110
111print("Retransmit spliced SYN+ACK packet to trigger ACK")
112send(ip/spliced_synack, iface=LOCAL_IF)
113
114sniffer.join(timeout=7)
115spliced_ack_retrans = sniffer.packet
116
117if spliced_ack_retrans is None:
118	print("ERROR: No spliced ACK retransmit packet received")
119	exit(1)
120if spliced_ack_retrans.seq != spliced_syn.seq+1+len(data):
121	print("ERROR: Expected seq %d, got %d in retransmitted spliced ack" %
122	    (spliced_syn.seq+1+len(data), spliced_ack_retrans.seq))
123	exit(1)
124if spliced_ack_retrans.ack != 1:
125	print("ERROR: Expected ack %d, got %d in retransmitted spliced ack" %
126	    (1, spliced_ack_retrans.ack))
127	exit(1)
128if spliced_ack_retrans.len-20-20 != 0:
129	print("ERROR: Expected len %d, got %d in retransmitted spliced ack" %
130	    (0, spliced_ack_retrans.len-20-20))
131	exit(1)
132
133print("Kill connections with RST")
134spliced_rst=TCP(sport=spliced_ack.dport, dport=spliced_ack.sport,
135    seq=1, ack=spliced_ack.seq, flags='RA')
136send(ip/spliced_rst, iface=LOCAL_IF)
137rst=TCP(sport=synack.dport, dport=synack.sport,
138    seq=payload_ack.ack, ack=synack.seq+1, flags='RA')
139send(ip/rst, iface=LOCAL_IF)
140
141exit(0)
142