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Date: Mon, 1 Nov 2021 18:34:50 +0200
From: Leonard Crestez <cdleonard@...il.com>
To: David Ahern <dsahern@...nel.org>, Shuah Khan <shuah@...nel.org>,
Dmitry Safonov <0x7f454c46@...il.com>,
Eric Dumazet <edumazet@...gle.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Herbert Xu <herbert@...dor.apana.org.au>,
Kuniyuki Iwashima <kuniyu@...zon.co.jp>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Jakub Kicinski <kuba@...nel.org>,
Yuchung Cheng <ycheng@...gle.com>,
Francesco Ruggeri <fruggeri@...sta.com>,
Mat Martineau <mathew.j.martineau@...ux.intel.com>,
Christoph Paasch <cpaasch@...le.com>,
Ivan Delalande <colona@...sta.com>,
Priyaranjan Jha <priyarjha@...gle.com>, netdev@...r.kernel.org,
linux-crypto@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 15/25] selftests: tcp_authopt: Implement SNE in python
Add implementation and tests for Sequence Number Extension.
One implementation is based on an IETF draft:
https://datatracker.ietf.org/doc/draft-touch-sne/
The linux implementation is simpler and doesn't require additional
flags, it just relies on standard before/after macros.
Signed-off-by: Leonard Crestez <cdleonard@...il.com>
---
.../tcp_authopt/tcp_authopt_test/sne_alg.py | 111 ++++++++++++++++++
.../tcp_authopt_test/test_sne_alg.py | 96 +++++++++++++++
2 files changed, 207 insertions(+)
create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/sne_alg.py
create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_sne_alg.py
diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/sne_alg.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/sne_alg.py
new file mode 100644
index 000000000000..252356dc87a4
--- /dev/null
+++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/sne_alg.py
@@ -0,0 +1,111 @@
+# SPDX-License-Identifier: GPL-2.0
+"""Python implementation of SNE algorithms"""
+
+
+def distance(x, y):
+ if x < y:
+ return y - x
+ else:
+ return x - y
+
+
+class SequenceNumberExtender:
+ """Based on https://datatracker.ietf.org/doc/draft-touch-sne/"""
+
+ sne: int = 0
+ sne_flag: int = 1
+ prev_seq: int = 0
+
+ def calc(self, seq):
+ """Update internal state and return SNE for certain SEQ"""
+ # use current SNE to start
+ result = self.sne
+
+ # both in same SNE range?
+ if distance(seq, self.prev_seq) < 0x80000000:
+ # jumps fwd over N/2?
+ if seq >= 0x80000000 and self.prev_seq < 0x80000000:
+ self.sne_flag = 0
+ # move prev forward if needed
+ self.prev_seq = max(seq, self.prev_seq)
+ # both in diff SNE ranges?
+ else:
+ # jumps forward over zero?
+ if seq < 0x80000000:
+ # update prev
+ self.prev_seq = seq
+ # first jump over zero? (wrap)
+ if self.sne_flag == 0:
+ # set flag so we increment once
+ self.sne_flag = 1
+ # increment window
+ self.sne = self.sne + 1
+ # use updated SNE value
+ result = self.sne
+ # jump backward over zero?
+ else:
+ # use pre-rollover SNE value
+ result = self.sne - 1
+
+ return result
+
+
+class SequenceNumberExtenderRFC:
+ """Based on sample code in original RFC5925 document"""
+
+ sne: int = 0
+ sne_flag: int = 1
+ prev_seq: int = 0
+
+ def calc(self, seq):
+ """Update internal state and return SNE for certain SEQ"""
+ # set the flag when the SEG.SEQ first rolls over
+ if self.sne_flag == 0 and self.prev_seq > 0x7FFFFFFF and seq < 0x7FFFFFFF:
+ self.sne = self.sne + 1
+ self.sne_flag = 1
+ # decide which SNE to use after incremented
+ if self.sne_flag and seq > 0x7FFFFFFF:
+ # use the pre-increment value
+ sne = self.sne - 1
+ else:
+ # use the current value
+ sne = self.sne
+ # reset the flag in the *middle* of the window
+ if self.prev_seq < 0x7FFFFFFF and seq > 0x7FFFFFFF:
+ self.sne_flag = 0
+ # save the current SEQ for the next time through the code
+ self.prev_seq = seq
+
+ return sne
+
+
+def tcp_seq_before(a, b) -> bool:
+ return ((a - b) & 0xFFFFFFFF) > 0x80000000
+
+
+def tcp_seq_after(a, b) -> bool:
+ return tcp_seq_before(a, b)
+
+
+class SequenceNumberExtenderLinux:
+ """Based on linux implementation and with no extra flags"""
+
+ sne: int = 0
+ prev_seq: int = 0
+
+ def reset(self, seq, sne=0):
+ self.prev_seq = seq
+ self.sne = sne
+
+ def calc(self, seq, update=True):
+ sne = self.sne
+ if tcp_seq_before(seq, self.prev_seq):
+ if seq > self.prev_seq:
+ sne -= 1
+ else:
+ if seq < self.prev_seq:
+ sne += 1
+ if update and tcp_seq_before(self.prev_seq, seq):
+ self.prev_seq = seq
+ self.sne = sne
+ return sne
diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_sne_alg.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_sne_alg.py
new file mode 100644
index 000000000000..9b74873cff4a
--- /dev/null
+++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_sne_alg.py
@@ -0,0 +1,96 @@
+# SPDX-License-Identifier: GPL-2.0
+"""Test SNE algorithm implementations"""
+
+import logging
+
+import pytest
+
+from .sne_alg import (
+ SequenceNumberExtender,
+ SequenceNumberExtenderLinux,
+ SequenceNumberExtenderRFC,
+)
+
+logger = logging.getLogger(__name__)
+
+
+# Data from https://datatracker.ietf.org/doc/draft-touch-sne/
+_SNE_TEST_DATA = [
+ (0x00000000, 0x00000000),
+ (0x00000000, 0x30000000),
+ (0x00000000, 0x90000000),
+ (0x00000000, 0x70000000),
+ (0x00000000, 0xA0000000),
+ (0x00000001, 0x00000001),
+ (0x00000000, 0xE0000000),
+ (0x00000001, 0x00000000),
+ (0x00000001, 0x7FFFFFFF),
+ (0x00000001, 0x00000000),
+ (0x00000001, 0x50000000),
+ (0x00000001, 0x80000000),
+ (0x00000001, 0x00000001),
+ (0x00000001, 0x40000000),
+ (0x00000001, 0x90000000),
+ (0x00000001, 0xB0000000),
+ (0x00000002, 0x0FFFFFFF),
+ (0x00000002, 0x20000000),
+ (0x00000002, 0x90000000),
+ (0x00000002, 0x70000000),
+ (0x00000002, 0xA0000000),
+ (0x00000003, 0x00004000),
+ (0x00000002, 0xD0000000),
+ (0x00000003, 0x20000000),
+ (0x00000003, 0x90000000),
+ (0x00000003, 0x70000000),
+ (0x00000003, 0xA0000000),
+ (0x00000004, 0x00004000),
+ (0x00000003, 0xD0000000),
+]
+
+
+# Easier test data with small jumps <= 0x30000000
+SNE_DATA_EASY = [
+ (0x00000000, 0x00000000),
+ (0x00000000, 0x30000000),
+ (0x00000000, 0x60000000),
+ (0x00000000, 0x80000000),
+ (0x00000000, 0x90000000),
+ (0x00000000, 0xC0000000),
+ (0x00000000, 0xF0000000),
+ (0x00000001, 0x10000000),
+ (0x00000000, 0xF0030000),
+ (0x00000001, 0x00030000),
+ (0x00000001, 0x10030000),
+]
+
+
+def check_sne_alg(alg, data):
+ for sne, seq in data:
+ observed_sne = alg.calc(seq)
+ logger.info(
+ "seq %08x expected sne %08x observed sne %08x", seq, sne, observed_sne
+ )
+ assert observed_sne == sne
+
+
+def test_sne_alg():
+ check_sne_alg(SequenceNumberExtender(), _SNE_TEST_DATA)
+
+
+def test_sne_alg_easy():
+ check_sne_alg(SequenceNumberExtender(), SNE_DATA_EASY)
+
+
+@...est.mark.xfail
+def test_sne_alg_rfc():
+ check_sne_alg(SequenceNumberExtenderRFC(), _SNE_TEST_DATA)
+
+
+@...est.mark.xfail
+def test_sne_alg_rfc_easy():
+ check_sne_alg(SequenceNumberExtenderRFC(), SNE_DATA_EASY)
+
+
+def test_sne_alg_linux():
+ check_sne_alg(SequenceNumberExtenderLinux(), _SNE_TEST_DATA)
+ check_sne_alg(SequenceNumberExtenderLinux(), SNE_DATA_EASY)
--
2.25.1
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