Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/tests/sys/netpfil/pf/frag-overhole.py
39507 views
1
#!/usr/bin/env python3

2
#

3
# Copyright (c) 2025 Alexander Bluhm <[email protected]>

4


5
from fragcommon import *

6


7
#                               index boundary 4096 |

8
# |--------------|

9
#                 ....

10
#                     |--------------|

11
#                                    |----------|

12
#                                               |XXXX----------|

13
#                                          |XXXX----|

14
#                                                               |---|

15


16
# this should trigger "frag tail overlap %d" and "frag head overlap %d"

17
def send(src, dst, send_if, recv_if):

18
	pid = os.getpid()

19
	eid = pid & 0xffff

20
	payload = b"ABCDEFGHIJKLMNOP"

21
	dummy = b"01234567"

22
	fragsize = 1024

23
	boundary = 4096

24
	fragnum = int(boundary / fragsize)

25
	packet = sp.IP(src=src, dst=dst)/ \

26
	    sp.ICMP(type='echo-request', id=eid)/ \

27
	    ((int((boundary + fragsize) / len(payload)) + 1) * payload)

28
	packet_length = len(packet)

29
	frag = []

30
	fid = pid & 0xffff

31
	for i in range(fragnum-1):

32
		frag.append(sp.IP(src=src, dst=dst, proto=1, id=fid,

33
		    frag=(i * fragsize)>>3, flags='MF')/

34
		    bytes(packet)[20 + i * fragsize:20 + (i + 1) * fragsize])

35
	frag.append(sp.IP(src=src, dst=dst, proto=1, id=fid,

36
	    frag=(boundary - fragsize) >> 3, flags='MF')/

37
	    bytes(packet)[20 + boundary - fragsize:20 + boundary - len(dummy)])

38
	frag.append(sp.IP(src=src, dst=dst, proto=1, id=fid,

39
	    frag=(boundary - len(dummy)) >> 3, flags='MF')/

40
	    (dummy+bytes(packet)[20 + boundary:20 + boundary + fragsize]))

41
	frag.append(sp.IP(src=src, dst=dst, proto=1, id=fid,

42
	    frag=(boundary - 8 - len(dummy)) >> 3, flags='MF')/

43
	    (dummy+bytes(packet)[20 + boundary - 8:20 + boundary]))

44
	frag.append(sp.IP(src=src, dst=dst, proto=1, id=fid,

45
	    frag=(boundary + fragsize) >> 3)/bytes(packet)[20 + boundary + fragsize:])

46
	eth=[]

47
	for f in frag:

48
		eth.append(sp.Ether() / f)

49


50
	if os.fork() == 0:

51
		time.sleep(1)

52
		for e in eth:

53
			sp.sendp(e, iface=send_if)

54
			time.sleep(0.001)

55
		os._exit(0)

56


57
	ans = sp.sniff(iface=recv_if, timeout=3, filter=

58
	    "ip and src " + dst + " and dst " + src + " and icmp")

59
	for a in ans:

60
		if a and a.type == sp.ETH_P_IP and \

61
		    a.payload.proto == 1 and \

62
		    a.payload.frag == 0 and \

63
		    sp.icmptypes[a.payload.payload.type] == 'echo-reply':

64
			id = a.payload.payload.id

65
			print("id=%#x" % (id))

66
			if id != eid:

67
				print("WRONG ECHO REPLY ID")

68
				exit(2)

69
		if a and a.type == sp.ETH_P_IP and \

70
		    a.payload.proto == 1 and \

71
		    a.payload.frag > 0 and \

72
		    a.payload.flags == '':

73
			length = (a.payload.frag << 3) + a.payload.len

74
			print("len=%d" % (length))

75
			if length != packet_length:

76
				print("WRONG ECHO REPLY LENGTH")

77
				exit(1)

78
			exit(0)

79
	print("NO ECHO REPLY")

80
	exit(1)

81


82
if __name__ == '__main__':

83
	main(send)

84


85