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pfroute: extract netmasks correctly on Darwin/NetBSD #5074

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pfroute: extract netmasks correctly on Darwin/NetBSD #5074

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4 changes: 2 additions & 2 deletions scapy/arch/bpf/pfroute.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1064,8 +1064,8 @@ def read_routes():
nm = msg.addrs[i]
if nm.sa_family == socket.AF_INET:
mask = atol(nm.sin_addr)
elif nm.sa_family in [0x00, 0xFF]: # NetBSD
mask = struct.unpack("<I", nm.sa_data[:4].rjust(4, b"\x00"))[0]
elif nm.sa_family in [0x00, 0xFF]: # Darwin, NetBSD
mask = struct.unpack("!I", nm.sa_data[2:].ljust(4, b"\x00"))[0]
else:
mask = int.from_bytes(nm.sa_data[:4], "big")
i += 1
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12 changes: 6 additions & 6 deletions test/regression.uts
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Expand Up @@ -3227,9 +3227,9 @@ with BSDLoader(NETBSD=True, sysctldata=_PFROUTE_DATA, ifaces=_NETBSD_IFACES, AF_

assert routes == [
(0, 0, '172.23.192.1', 'hvn0', '172.23.207.191', 1),
(2130706432, 4294967040, '127.0.0.1', 'lo0', '127.0.0.1', 1),
(2130706432, 4278190080, '127.0.0.1', 'lo0', '127.0.0.1', 1),
(2130706433, 4294967295, '0.0.0.0', 'lo0', '127.0.0.1', 1),
(2887237632, 4294967295, '0.0.0.0', 'hvn0', '172.23.207.191', 1),
(2887237632, 4294963200, '0.0.0.0', 'hvn0', '172.23.207.191', 1),

@evverx evverx Aug 4, 2026

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This is a cool test in the sense that it helped me to notice the wrong byte order. The corresponding sockaddrs are

[<sockaddr  sa_len=16 sa_family=AF_INET sin_port=0 sin_addr=172.23.192.0 sin_zero=b'' |>,
 <sockaddr  sa_len=18 sa_family=AF_LINK sdl_index=1 sdl_type=6 sdl_nlen=0 sdl_alen=0 sdl_slen=0 sdl_iface=b'' sdl_addr=b'' sdl_sel=b'' sdl_data=00000000000000000000 |>,
 <sockaddr  sa_len=7 sa_family=255 sa_data=fffffffff0 |>,
 <sockaddr  sa_len=18 sa_family=AF_LINK sdl_index=1 sdl_type=6 sdl_nlen=4 sdl_alen=6 sdl_slen=0 sdl_iface=b'hvn0' sdl_addr=00:15:5d:00:65:0a sdl_sel=b'' sdl_data= |>,
 <sockaddr  sa_len=16 sa_family=AF_INET sin_port=0 sin_addr=172.23.207.191 sin_zero=b'' |>]

and looking at

>>>  pfmsghdrs(b).msgs[3].addrs[2].sa_data[2:]
b'\xff\xff\xf0'

it's kind of obvious that the netmask should be /20 (255.255.240.0) but it produced 240.255.255.0 instead. I had /4, /8,/24 and /32 locally and it worked regardless of the order but /20 is different.

(2887241663, 4294967295, '0.0.0.0', 'lo0', '172.23.207.191', 1),
(2887237633, 4294967295, '0.0.0.0', 'hvn0', '', 1),
(3758096384, 4026531840, '0.0.0.0', 'hvn0', '172.23.207.191', 250),
Expand Down Expand Up @@ -3292,16 +3292,16 @@ with BSDLoader(DARWIN=True, sysctldata=_PFROUTE_DATA, ifaces=_DARWIN_IFACES, AF_

assert routes == [
(0, 0, '10.0.2.2', 'en0', '10.0.2.15', 1),
(167772672, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(167772672, 4294967040, '0.0.0.0', 'en0', '10.0.2.15', 1),
(167772674, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(167772674, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(167772675, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(167772687, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(167772927, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(2130706432, 4294967040, '127.0.0.1', 'lo0', '127.0.0.1', 1),
(2130706432, 4278190080, '127.0.0.1', 'lo0', '127.0.0.1', 1),
(2130706433, 4294967295, '127.0.0.1', 'lo0', '127.0.0.1', 1),
(2851995648, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(3758096384, 4043308800, '0.0.0.0', 'en0', '10.0.2.15', 1),
(2851995648, 4294901760, '0.0.0.0', 'en0', '10.0.2.15', 1),
(3758096384, 4026531840, '0.0.0.0', 'en0', '10.0.2.15', 1),
(3758096635, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1),
(4294967295, 4294967295, '0.0.0.0', 'en0', '10.0.2.15', 1)
]
Expand Down
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