# Copyright 2020 Red Hat, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import socket
import struct
import sys
import time
import random
# Adapted from https://opendev.org/openstack/os-ken/src/branch/
# master/os_ken/lib/packet/sctp.py
[docs]
def crc32c(data):
# from RFC 3309
crc_c = [
0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4,
0xC79A971F, 0x35F1141C, 0x26A1E7E8, 0xD4CA64EB,
0x8AD958CF, 0x78B2DBCC, 0x6BE22838, 0x9989AB3B,
0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 0x5E133C24,
0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B,
0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384,
0x9A879FA0, 0x68EC1CA3, 0x7BBCEF57, 0x89D76C54,
0x5D1D08BF, 0xAF768BBC, 0xBC267848, 0x4E4DFB4B,
0x20BD8EDE, 0xD2D60DDD, 0xC186FE29, 0x33ED7D2A,
0xE72719C1, 0x154C9AC2, 0x061C6936, 0xF477EA35,
0xAA64D611, 0x580F5512, 0x4B5FA6E6, 0xB93425E5,
0x6DFE410E, 0x9F95C20D, 0x8CC531F9, 0x7EAEB2FA,
0x30E349B1, 0xC288CAB2, 0xD1D83946, 0x23B3BA45,
0xF779DEAE, 0x05125DAD, 0x1642AE59, 0xE4292D5A,
0xBA3A117E, 0x4851927D, 0x5B016189, 0xA96AE28A,
0x7DA08661, 0x8FCB0562, 0x9C9BF696, 0x6EF07595,
0x417B1DBC, 0xB3109EBF, 0xA0406D4B, 0x522BEE48,
0x86E18AA3, 0x748A09A0, 0x67DAFA54, 0x95B17957,
0xCBA24573, 0x39C9C670, 0x2A993584, 0xD8F2B687,
0x0C38D26C, 0xFE53516F, 0xED03A29B, 0x1F682198,
0x5125DAD3, 0xA34E59D0, 0xB01EAA24, 0x42752927,
0x96BF4DCC, 0x64D4CECF, 0x77843D3B, 0x85EFBE38,
0xDBFC821C, 0x2997011F, 0x3AC7F2EB, 0xC8AC71E8,
0x1C661503, 0xEE0D9600, 0xFD5D65F4, 0x0F36E6F7,
0x61C69362, 0x93AD1061, 0x80FDE395, 0x72966096,
0xA65C047D, 0x5437877E, 0x4767748A, 0xB50CF789,
0xEB1FCBAD, 0x197448AE, 0x0A24BB5A, 0xF84F3859,
0x2C855CB2, 0xDEEEDFB1, 0xCDBE2C45, 0x3FD5AF46,
0x7198540D, 0x83F3D70E, 0x90A324FA, 0x62C8A7F9,
0xB602C312, 0x44694011, 0x5739B3E5, 0xA55230E6,
0xFB410CC2, 0x092A8FC1, 0x1A7A7C35, 0xE811FF36,
0x3CDB9BDD, 0xCEB018DE, 0xDDE0EB2A, 0x2F8B6829,
0x82F63B78, 0x709DB87B, 0x63CD4B8F, 0x91A6C88C,
0x456CAC67, 0xB7072F64, 0xA457DC90, 0x563C5F93,
0x082F63B7, 0xFA44E0B4, 0xE9141340, 0x1B7F9043,
0xCFB5F4A8, 0x3DDE77AB, 0x2E8E845F, 0xDCE5075C,
0x92A8FC17, 0x60C37F14, 0x73938CE0, 0x81F80FE3,
0x55326B08, 0xA759E80B, 0xB4091BFF, 0x466298FC,
0x1871A4D8, 0xEA1A27DB, 0xF94AD42F, 0x0B21572C,
0xDFEB33C7, 0x2D80B0C4, 0x3ED04330, 0xCCBBC033,
0xA24BB5A6, 0x502036A5, 0x4370C551, 0xB11B4652,
0x65D122B9, 0x97BAA1BA, 0x84EA524E, 0x7681D14D,
0x2892ED69, 0xDAF96E6A, 0xC9A99D9E, 0x3BC21E9D,
0xEF087A76, 0x1D63F975, 0x0E330A81, 0xFC588982,
0xB21572C9, 0x407EF1CA, 0x532E023E, 0xA145813D,
0x758FE5D6, 0x87E466D5, 0x94B49521, 0x66DF1622,
0x38CC2A06, 0xCAA7A905, 0xD9F75AF1, 0x2B9CD9F2,
0xFF56BD19, 0x0D3D3E1A, 0x1E6DCDEE, 0xEC064EED,
0xC38D26C4, 0x31E6A5C7, 0x22B65633, 0xD0DDD530,
0x0417B1DB, 0xF67C32D8, 0xE52CC12C, 0x1747422F,
0x49547E0B, 0xBB3FFD08, 0xA86F0EFC, 0x5A048DFF,
0x8ECEE914, 0x7CA56A17, 0x6FF599E3, 0x9D9E1AE0,
0xD3D3E1AB, 0x21B862A8, 0x32E8915C, 0xC083125F,
0x144976B4, 0xE622F5B7, 0xF5720643, 0x07198540,
0x590AB964, 0xAB613A67, 0xB831C993, 0x4A5A4A90,
0x9E902E7B, 0x6CFBAD78, 0x7FAB5E8C, 0x8DC0DD8F,
0xE330A81A, 0x115B2B19, 0x020BD8ED, 0xF0605BEE,
0x24AA3F05, 0xD6C1BC06, 0xC5914FF2, 0x37FACCF1,
0x69E9F0D5, 0x9B8273D6, 0x88D28022, 0x7AB90321,
0xAE7367CA, 0x5C18E4C9, 0x4F48173D, 0xBD23943E,
0xF36E6F75, 0x0105EC76, 0x12551F82, 0xE03E9C81,
0x34F4F86A, 0xC69F7B69, 0xD5CF889D, 0x27A40B9E,
0x79B737BA, 0x8BDCB4B9, 0x988C474D, 0x6AE7C44E,
0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 0xAD7D5351,
]
crc32 = 0xffffffff
for c in data:
crc32 = (crc32 >> 8) ^ crc_c[(crc32 ^ (c)) & 0xFF]
crc32 = (~crc32) & 0xffffffff
return struct.unpack(">I", struct.pack("<I", crc32))[0]
def _sctp_build_init_packet(src_port, dest_port, tag):
sctp_hdr = [
# HEADER
struct.pack('!H', src_port), # Source port number
struct.pack('!H', dest_port), # Destination port number
struct.pack('!L', 0), # Verification tag
struct.pack('!L', 0), # checksum
# INIT Chunk
struct.pack('!B', 1), # Type
struct.pack('!B', 0), # Chunk flag
struct.pack('!H', 0), # Chunk length
struct.pack('!L', tag), # Tag
struct.pack('!L', 106496), # a_rwnd
struct.pack('!H', 10), # Number of outbound stream
struct.pack('!H', 65535), # Number of inbound stream
struct.pack('!L',
random.randint(
1, 4294967295)), # Initial TSN
]
data = bytearray(b''.join(sctp_hdr))
chunk_len = len(data) - 12
struct.pack_into('!H', data, 14, chunk_len)
checksum = crc32c(data)
struct.pack_into('!L', data, 8, checksum)
return data
def _sctp_build_abort_packet(src_port, dest_port, verification_tag):
sctp_hdr = [
# HEADER
struct.pack('!H', src_port), # Source port number
struct.pack('!H', dest_port), # Destination port number
struct.pack('!L', verification_tag), # Verification tag
struct.pack('!L', 0), # checksum
# ABORT Chunk
struct.pack('!B', 6), # Type
struct.pack('!B', 1), # Chunk flag
struct.pack('!H', 4), # Chunk length
]
data = bytearray(b''.join(sctp_hdr))
checksum = crc32c(data)
struct.pack_into('!L', data, 8, checksum)
return data
def _sctp_decode_packet(data, family, expected_tag):
# AF_INET packets contain ipv4 header
if family == socket.AF_INET:
hdr_offset = (data[0] & 0xf) << 2
else:
hdr_offset = 0
if len(data) - hdr_offset < 16:
return False
# Check if the packet is a reply to our INIT packet
verification_tag = struct.unpack_from('!L', data, hdr_offset + 4)[0]
if verification_tag != expected_tag:
return False
response_type = data[hdr_offset + 12]
return response_type
[docs]
def sctp_health_check(ip_address, port, timeout=2):
family = socket.AF_INET6 if ':' in ip_address else socket.AF_INET
s = socket.socket(family, socket.SOCK_RAW, socket.IPPROTO_SCTP)
s.settimeout(.2)
s.connect((ip_address, port))
tag = random.randint(1, 4294967295)
src_port = random.randint(1024, 65535)
data = _sctp_build_init_packet(src_port, port, tag)
print(f"Sending INIT packet to {ip_address}:{port}")
s.send(data)
start = time.time()
send_abort = False
while time.time() - start < timeout:
try:
buf, addr = s.recvfrom(1500)
except socket.timeout:
continue
response_type = _sctp_decode_packet(buf, family, tag)
if response_type is False:
continue
if response_type == 2: # INIT ACK
print("Received INIT ACK")
send_abort = True
ret = 0
elif response_type == 6: # ABORT
print("Received ABORT")
ret = 1
else: # Others: unknown error
print(f"Received {response_type} Type chunk")
send_abort = True
ret = 3
break
else:
print(f"Timeout after {timeout} seconds.")
# Timeout
ret = 2
if send_abort:
has_sctp_support = False
with open("/proc/net/protocols", encoding='utf-8') as fp:
for line in fp:
if line.startswith('SCTP'):
has_sctp_support = True
# if SCTP support is not included in the kernel, closing the socket
# won't automatically send a ABORT packet, we need to craft it.
if not has_sctp_support:
data = _sctp_build_abort_packet(src_port, port, tag)
print("Sending ABORT packet")
s.send(data)
s.close()
return ret
[docs]
def main():
default_timeout = 3
args = sys.argv[1:]
protocol = args.pop(0)
if args[0] == '-t':
args.pop(0)
default_timeout = int(args.pop(0))
if protocol.lower() == 'sctp':
destination = args[0]
port = int(args[1])
ret = sctp_health_check(destination, port, timeout=default_timeout)
sys.exit(ret)
else:
print(f"Unsupported protocol '{protocol}'")
sys.exit(1)
