From 698ef42c6c295e9182c3b2a72d02a3bc5e9f939a Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@gmail.com>
Date: Sat, 25 Feb 2023 11:26:59 +0000
Subject: [PATCH] unify setting to memory
this modifies the tests to do some multiplication not long -
but it actually seems legit.
---
ebpfcat/ebpf.py | 136 +++++++++++++++++++------------------------
ebpfcat/ebpf_test.py | 4 +-
2 files changed, 62 insertions(+), 78 deletions(-)
diff --git a/ebpfcat/ebpf.py b/ebpfcat/ebpf.py
index f1949e6..b74a64e 100644
--- a/ebpfcat/ebpf.py
+++ b/ebpfcat/ebpf.py
@@ -966,6 +966,61 @@ class Memory(Expression):
return Memory(self.ebpf, "B", self.address) & mask != 0
return super().__ne__(value)
+ def _set(self, value):
+ opcode = Opcode.STX
+ if isinstance(self.fmt, tuple):
+ pos, bits = self.fmt
+ self.fmt = "B"
+ if bits == 1:
+ try:
+ if value:
+ value = self | (1 << pos)
+ else:
+ value = self & ~(1 << pos)
+ except AssembleError:
+ with ebpf.wtmp:
+ with value as Else:
+ ebpf.wtmp = self | (1 << pos)
+ with Else:
+ ebpf.wtmp = self & ~(1 << pos)
+ else:
+ mask = ((1 << bits) - 1) << pos
+ value = (mask & (value << pos) | ~mask & self)
+ elif isinstance(value, IAdd) and len(self.fmt) == 1:
+ value = value.value
+ opcode = Opcode.XADD
+ elif not isinstance(value, Expression):
+ if self.fmt == "x":
+ value = Constant(self.ebpf, value)
+ else:
+ value = Constant(self.ebpf,
+ *unpack(self.fmt, pack(self.fmt[-1], value)))
+ if self.fmt == "x" and not value.fixed:
+ value *= Expression.FIXED_BASE
+ elif self.fmt != "x" and value.fixed:
+ value /= Expression.FIXED_BASE
+ with ExitStack() as exitStack:
+ if isinstance(self.address, Sum):
+ dst = self.address.left.no
+ offset = self.address.right.value
+ else:
+ dst, _ = exitStack.enter_context(
+ self.address.calculate(None, True))
+ offset = 0
+ if isinstance(value, Constant) and value.small \
+ and opcode == Opcode.STX:
+ self.ebpf.append(Opcode.ST + fmt_to_opcode(self.fmt), dst, 0,
+ offset, int(value.value))
+ return
+ src, _ = exitStack.enter_context(
+ value.calculate(None, isinstance(self.fmt, str)
+ and self.fmt[-1] in 'qQx'))
+ if not isinstance(value, Constant):
+ self.ebpf.append_endian(self.fmt, src)
+ self.ebpf.append(opcode + fmt_to_opcode(self.fmt),
+ dst, src, offset, 0)
+
+
class MemoryDesc:
"""A base class used by descriptors for memory
@@ -985,49 +1040,10 @@ class MemoryDesc:
instance.ebpf.r[self.base_register] + addr)
def __set__(self, instance, value):
- ebpf = instance.ebpf
fmt, addr = self.fmt_addr(instance)
- opcode = Opcode.STX
- if isinstance(fmt, tuple):
- before = Memory(ebpf, "B", ebpf.r[self.base_register] + addr)
- if fmt[1] == 1:
- try:
- if value:
- value = before | (1 << fmt[0])
- else:
- value = before & ~(1 << fmt[0])
- except AssembleError:
- with ebpf.wtmp:
- with value as Else:
- ebpf.wtmp = before | (1 << fmt[0])
- with Else:
- ebpf.wtmp = before & ~(1 << fmt[0])
- else:
- mask = ((1 << fmt[1]) - 1) << fmt[0]
- value = (mask & (value << self.fmt[0]) | ~mask & before)
- elif isinstance(value, IAdd) and len(fmt) == 1:
- value = value.value
- opcode = Opcode.XADD
- elif not isinstance(value, Expression):
- if fmt == "x":
- value = Constant(ebpf, value)
- else:
- value = Constant(ebpf, *unpack(fmt, pack(fmt[-1], value)))
- if self.fmt == "x" and not value.fixed:
- value *= Expression.FIXED_BASE
- elif self.fmt != "x" and value.fixed:
- value /= Expression.FIXED_BASE
- if isinstance(value, Constant) and value.small and opcode == Opcode.STX:
- ebpf.append(Opcode.ST + fmt_to_opcode(fmt), self.base_register, 0,
- addr, int(value.value))
- return
- with value.calculate(None, isinstance(fmt, str) and fmt[-1] in 'qQx'
- ) as (src, _):
- if not isinstance(value, Constant):
- ebpf.append_endian(fmt, src)
- ebpf.append(opcode + fmt_to_opcode(fmt), self.base_register,
- src, addr, 0)
-
+ memory = Memory(instance.ebpf, fmt,
+ instance.ebpf.r[self.base_register] + addr)
+ memory._set(value)
class LocalVar(MemoryDesc):
"""variables on the stack"""
@@ -1062,40 +1078,8 @@ class MemoryMap:
self.fmt = fmt
def __setitem__(self, addr, value):
- with ExitStack() as exitStack:
- if isinstance(addr, Sum):
- dst = addr.left.no
- offset = addr.right.value
- else:
- dst, _ = exitStack.enter_context(addr.calculate(None, True))
- offset = 0
- if isinstance(value, IAdd):
- value = value.value
- if self.fmt == "x":
- value = int(value * self.FIXED_BASE)
- if not isinstance(value, Expression):
- with self.ebpf.get_free_register(None) as src:
- self.ebpf.r[src] = value
- self.ebpf.append(
- Opcode.XADD + fmt_to_opcode(self.fmt),
- dst, src, offset, 0)
- return
- opcode = Opcode.XADD
- elif isinstance(value, Expression):
- opcode = Opcode.STX
- else:
- value = Constant(self.ebpf, value)
- if value.small:
- if self.fmt == "x":
- value *= self.FIXED_BASE
- self.ebpf.append(Opcode.ST + fmt_to_opcode(self.fmt), dst, 0,
- offset, int(value.value))
- return
- with value.calculate(None, None) as (src, _):
- if not isinstance(value, Constant):
- self.ebpf.append_endian(self.fmt, src)
- self.ebpf.append(opcode + fmt_to_opcode(self.fmt),
- dst, src, offset, 0)
+ memory = Memory(self.ebpf, self.fmt, addr)
+ memory._set(value)
def __getitem__(self, addr):
if isinstance(addr, Register):
diff --git a/ebpfcat/ebpf_test.py b/ebpfcat/ebpf_test.py
index 0b36f02..aa81111 100644
--- a/ebpfcat/ebpf_test.py
+++ b/ebpfcat/ebpf_test.py
@@ -810,12 +810,12 @@ class Tests(TestCase):
Instruction(opcode=39, dst=0, src=0, off=0, imm=2),
Instruction(opcode=31, dst=3, src=0, off=0, imm=0),
Instruction(opcode=191, dst=0, src=3, off=0, imm=0),
- Instruction(opcode=O.MUL+O.LONG, dst=0, src=0, off=0, imm=2),
+ Instruction(opcode=O.MUL, dst=0, src=0, off=0, imm=2),
Instruction(opcode=107, dst=10, src=0, off=-10, imm=0),
Instruction(opcode=191, dst=0, src=10, off=0, imm=0),
Instruction(opcode=15, dst=0, src=3, off=0, imm=0),
Instruction(opcode=191, dst=2, src=3, off=0, imm=0),
- Instruction(opcode=O.MUL+O.LONG, dst=2, src=0, off=0, imm=2),
+ Instruction(opcode=O.MUL, dst=2, src=0, off=0, imm=2),
Instruction(opcode=107, dst=0, src=2, off=0, imm=0),
Instruction(opcode=191, dst=5, src=10, off=0, imm=0),
--
GitLab