From 183a37fb84c6b7790e312e93976a059c41bdd316 Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@xfel.eu>
Date: Mon, 28 Dec 2020 14:04:16 +0000
Subject: [PATCH] amidst making & and | work for If
super complicated, pausing.
---
ebpf.py | 108 +++++++++++++++++++++++++++++++++++----------------
ebpf_test.py | 7 ++--
2 files changed, 78 insertions(+), 37 deletions(-)
diff --git a/ebpf.py b/ebpf.py
index bd219c2..cca2f1f 100644
--- a/ebpf.py
+++ b/ebpf.py
@@ -32,35 +32,33 @@ def comparison(uposop, unegop, sposop=None, snegop=None):
class Comparison:
- def target(self):
- assert self.ebpf.opcodes[self.origin] is None
- if isinstance(self.right, int):
- inst = Instruction(
- self.opcode, self.dst, 0,
- len(self.ebpf.opcodes) - self.origin - 1, self.right)
- else:
- inst = Instruction(
- self.opcode + 8, self.dst, self.src,
- len(self.ebpf.opcodes) - self.origin - 1, 0)
- self.ebpf.opcodes[self.origin] = inst
- self.ebpf.owners, self.owners = \
- self.ebpf.owners & self.owners, self.ebpf.owners
+ def __init__(self, ebpf):
+ self.ebpf = ebpf
+ self.invert = None
+ self.else_origin = None
def __enter__(self):
return self
def __exit__(self, exc_type, exc, tb):
- self.target()
+ if self.else_origin is None:
+ self.target()
+ return
+ assert self.ebpf.opcodes[self.else_origin] is None
+ self.ebpf.opcodes[self.else_origin] = Instruction(5, 0, 0, len(self.ebpf.opcodes) - self.else_origin - 1, 0)
+ self.ebpf.owners, self.owners = \
+ self.ebpf.owners & self.owners, self.ebpf.owners
+
if self.invert is not None:
olen = len(self.ebpf.opcodes)
assert self.ebpf.opcodes[self.invert].opcode == 5
self.ebpf.opcodes[self.invert:self.invert] = \
- self.ebpf.opcodes[self.origin+1:]
+ self.ebpf.opcodes[self.else_origin+1:]
del self.ebpf.opcodes[olen-1:]
op, dst, src, off, imm = self.ebpf.opcodes[self.invert - 1]
self.ebpf.opcodes[self.invert - 1] = \
Instruction(op, dst, src,
- len(self.ebpf.opcodes) - self.origin + 1, imm)
+ len(self.ebpf.opcodes) - self.else_origin + 1, imm)
def Else(self):
op, dst, src, off, imm = self.ebpf.opcodes[self.origin]
@@ -69,20 +67,34 @@ class Comparison:
else:
self.ebpf.opcodes[self.origin] = \
Instruction(op, dst, src, off+1, imm)
- self.origin = len(self.ebpf.opcodes)
+ self.else_origin = len(self.ebpf.opcodes)
+ self.ebpf.opcodes.append(None)
+ return self
+
+ def invert_result(self):
+ origin = len(self.ebpf.opcodes)
self.ebpf.opcodes.append(None)
+ self.target()
+ self.origin = origin
self.right = self.dst = 0
self.opcode = 5
- return self
+
+ def __and__(self, value):
+ return AndOrComparison(self.ebpf, self, value, True)
+
+ def __or__(self, value):
+ return AndOrComparison(self.ebpf, self, value, False)
+
+ def __invert__(self):
+ return InvertComparison(self.ebpf, self)
class SimpleComparison(Comparison):
def __init__(self, ebpf, left, right, opcode):
- self.ebpf = ebpf
+ super().__init__(ebpf)
self.left = left
self.right = right
self.opcode = opcode
- self.invert = None
def compare(self, negative):
self.dst, _, lsigned, lfree = self.left.calculate(None, None, None)
@@ -102,14 +114,52 @@ class SimpleComparison(Comparison):
self.ebpf.owners.discard(self.src)
self.owners = self.ebpf.owners.copy()
+ def target(self):
+ assert self.ebpf.opcodes[self.origin] is None
+ if isinstance(self.right, int):
+ inst = Instruction(
+ self.opcode, self.dst, 0,
+ len(self.ebpf.opcodes) - self.origin - 1, self.right)
+ else:
+ inst = Instruction(
+ self.opcode + 8, self.dst, self.src,
+ len(self.ebpf.opcodes) - self.origin - 1, 0)
+ self.ebpf.opcodes[self.origin] = inst
+ self.ebpf.owners, self.owners = \
+ self.ebpf.owners & self.owners, self.ebpf.owners
+
+
class AndOrComparison(Comparison):
+ def __init__(self, ebpf, left, right, is_and):
+ super().__init__(ebpf)
+ self.left = left
+ self.right = right
+ self.is_and = is_and
+ self.targetted = False
+
def compare(self, negative):
- self.left.compare(negative)
- self.right.compare(negative)
+ self.left.compare(self.is_and != negative)
+ self.right.compare(self.is_and != negative)
+ if self.is_and != negative:
+ self.invert_result()
+ self.owners = self.ebpf.owners.copy()
def target(self):
- self.left.target()
- self.right.target()
+ if self.targetted:
+ super().target()
+ else:
+ self.left.target()
+ self.right.target()
+ self.targetted = True
+
+
+class InvertComparison(Comparison):
+ def __init__(self, ebpf, value):
+ self.ebpf = ebpf
+ self.value = value
+
+ def compare(self, negative):
+ self.value.compare(not negative)
def binary(opcode, symetric=False):
@@ -192,9 +242,6 @@ class Sum(Binary):
class AndExpression(Binary, SimpleComparison):
- __and__ = __rand__ = comparison(0x45, None)
- __rand__ = __and__ = binary(0x54, True)
-
def __init__(self, ebpf, left, right):
Binary.__init__(self, ebpf, left, right, 0x54)
SimpleComparison.__init__(self, ebpf, left, right, 0x45)
@@ -203,12 +250,7 @@ class AndExpression(Binary, SimpleComparison):
def compare(self, negative):
super().compare(False)
if negative:
- origin = len(self.ebpf.opcodes)
- self.ebpf.opcodes.append(None)
- self.target()
- self.origin = origin
- self.right = self.dst = 0
- self.opcode = 5
+ self.invert_result()
class Register(Expression):
offset = 0
diff --git a/ebpf_test.py b/ebpf_test.py
index a50dbc6..243f9b5 100644
--- a/ebpf_test.py
+++ b/ebpf_test.py
@@ -394,11 +394,10 @@ class Tests(TestCase):
class KernelTests(TestCase):
def test_minimal(self):
e = EBPF(ProgType.XDP, "GPL")
- with e.If(e.r1 & 1111111) as cond:
- e.r0 = 2
- e.r1 = 4
+ with e.If((e.r1 == 0x111111) & (e.r10 == 0x22222)) as cond:
+ e.r0 = 333333
with cond.Else():
- e.r0 = 3
+ e.r0 = 444444
e.exit()
print(e.load(log_level=1)[1])
self.fail()
--
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