diff --git a/ebpf.py b/ebpf.py
index 96209e71a205398cb57b2fcc1d25db029c38054e..a95d5d6b4dc615190bb3568abccfa596cb171ee2 100644
--- a/ebpf.py
+++ b/ebpf.py
@@ -37,8 +37,9 @@ class Comparison:
self.left = left
self.right = right
self.opcode = opcode
+ self.invert = None
- def calculate(self, negative):
+ def compare(self, negative):
self.dst, _, lsigned, lfree = self.left.calculate(None, None, None)
if not isinstance(self.right, int):
self.src, _, rsigned, rfree = \
@@ -75,10 +76,24 @@ class Comparison:
def __exit__(self, exc_type, exc, tb):
self.target()
+ 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:]
+ 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)
def Else(self):
op, dst, src, off, imm = self.ebpf.opcodes[self.origin]
- self.ebpf.opcodes[self.origin] = Instruction(op, dst, src, off+1, imm)
+ if op == 5:
+ self.invert = self.origin
+ else:
+ self.ebpf.opcodes[self.origin] = \
+ Instruction(op, dst, src, off+1, imm)
self.origin = len(self.ebpf.opcodes)
self.ebpf.opcodes.append(None)
self.right = self.dst = 0
@@ -86,10 +101,14 @@ class Comparison:
return self
+class OrComparison(Comparison):
+ def compare(self, negative):
+ self.left.compare(negative)
+ self.right.compare(negative)
+
+
def binary(opcode, symetric=False):
def ret(self, value):
- #if symetric and isinstance(value, Register):
- # return Binary(self.ebpf, value, self, opcode)
return Binary(self.ebpf, self, value, opcode)
return ret
@@ -100,7 +119,6 @@ class Expression:
__rmul__ = __mul__ = binary(0x24, True)
__truediv__ = binary(0x34)
__ror__ = __or__ = binary(0x44, True)
- __rand__ = __and__ = binary(0x54, True)
__lshift__ = binary(0x64)
__rshift__ = binary(0x74)
__mod__ = binary(0x94)
@@ -112,7 +130,11 @@ class Expression:
__lt__ = comparison(0xa5, 0x35, 0xc5, 0x75)
__le__ = comparison(0xb5, 0x25, 0xd5, 0x65)
__ne__ = comparison(0x55, 0x15)
- __and__ = __rand__ = comparison(0x45, None)
+
+ def __and__(self, value):
+ return AndExpression(self.ebpf, self, value)
+
+ __rand__ = __and__
class Binary(Expression):
@@ -164,6 +186,25 @@ class Sum(Binary):
return super().__sub__(value)
+class AndExpression(Binary, Comparison):
+ __and__ = __rand__ = comparison(0x45, None)
+ __rand__ = __and__ = binary(0x54, True)
+
+ def __init__(self, ebpf, left, right):
+ Binary.__init__(self, ebpf, left, right, 0x54)
+ Comparison.__init__(self, ebpf, left, right, 0x45)
+ self.opcode = (0x45, None, 0x45, None)
+
+ 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
+
class Register(Expression):
offset = 0
@@ -347,7 +388,7 @@ class EBPF:
log_level, log_size, self.kern_version)
def jumpIf(self, comp):
- comp.calculate(False)
+ comp.compare(False)
return comp
def jump(self):
@@ -360,11 +401,7 @@ class EBPF:
return comp
def If(self, comp):
- comp.calculate(True)
- return comp
-
- def isZero(self, comp):
- comp.calculate(False)
+ comp.compare(True)
return comp
def get_fd(self, fd):
diff --git a/ebpf_test.py b/ebpf_test.py
index 91cfcd8387c143e6f851125e7e7634ee1a70080e..a50dbc69ef4c6a396df696c3498b65f8dc7a4697 100644
--- a/ebpf_test.py
+++ b/ebpf_test.py
@@ -211,6 +211,25 @@ class Tests(TestCase):
Instruction(opcode=0x5, dst=0, src=0, off=1, imm=0),
Instruction(opcode=0xb7, dst=6, src=0, off=0, imm=7)])
+ def test_with_inversion(self):
+ e = EBPF()
+ with e.If(e.r1 & 1) as cond:
+ e.r0 = 2
+ with e.If(e.r1 & 7) as cond:
+ e.r0 = 2
+ e.r1 = 4
+ with cond.Else():
+ e.r0 = 3
+ self.assertEqual(e.opcodes, [
+ Instruction(opcode=69, dst=1, src=0, off=1, imm=1),
+ Instruction(opcode=5, dst=0, src=0, off=1, imm=0),
+ Instruction(opcode=183, dst=0, src=0, off=0, imm=2),
+ Instruction(opcode=69, dst=1, src=0, off=2, imm=7),
+ Instruction(opcode=183, dst=0, src=0, off=0, imm=3),
+ Instruction(opcode=5, dst=0, src=0, off=2, imm=0),
+ Instruction(opcode=183, dst=0, src=0, off=0, imm=2),
+ Instruction(opcode=183, dst=1, src=0, off=0, imm=4)])
+
def test_comp_binary(self):
e = EBPF()
e.owners = {1, 2, 3, 5}
@@ -256,6 +275,7 @@ class Tests(TestCase):
e.sr0 = e.sr1 >> 2
e.sr0 = e.sr1 >> e.r2
e.w0 = e.w1 + e.w2
+ e.r0 = e.r1 & e.r2 # attention, special case
self.assertEqual(e.opcodes, [
Instruction(opcode=191, dst=0, src=1, off=0, imm=0),
Instruction(opcode=47, dst=0, src=2, off=0, imm=0),
@@ -277,7 +297,9 @@ class Tests(TestCase):
Instruction(opcode=191, dst=0, src=1, off=0, imm=0),
Instruction(opcode=207, dst=0, src=2, off=0, imm=0),
Instruction(opcode=188, dst=0, src=1, off=0, imm=0),
- Instruction(opcode=12, dst=0, src=2, off=0, imm=0)])
+ Instruction(opcode=12, dst=0, src=2, off=0, imm=0),
+ Instruction(opcode=191, dst=0, src=1, off=0, imm=0),
+ Instruction(opcode=95, dst=0, src=2, off=0, imm=0)])
def test_jump_data(self):
@@ -372,12 +394,11 @@ class Tests(TestCase):
class KernelTests(TestCase):
def test_minimal(self):
e = EBPF(ProgType.XDP, "GPL")
- e.r3 = 3
- e.r4 = 5
- e.r5 = 7
- tgt = e.jumpIf(e.r3 < e.r4 + e.r5)
- e.r0 = 8
- tgt.target()
+ with e.If(e.r1 & 1111111) as cond:
+ e.r0 = 2
+ e.r1 = 4
+ with cond.Else():
+ e.r0 = 3
e.exit()
print(e.load(log_level=1)[1])
self.fail()