From dbf16e610e2318dcd3f0a3b2e1422e3663ded36a Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@xfel.eu>
Date: Tue, 29 Dec 2020 08:31:21 +0000
Subject: [PATCH] make HashMap work on user side
---
ebpf.py | 68 +++++++++++++++++++++++++++++++++-------------------
ebpf_test.py | 17 ++++++++++++-
2 files changed, 59 insertions(+), 26 deletions(-)
diff --git a/ebpf.py b/ebpf.py
index caae0c9..9238663 100644
--- a/ebpf.py
+++ b/ebpf.py
@@ -1,9 +1,9 @@
from collections import namedtuple
from contextlib import contextmanager, ExitStack
-from struct import pack
+from struct import pack, unpack
from enum import Enum
-from .bpf import create_map, prog_load
+from . import bpf
Instruction = namedtuple("Instruction",
["opcode", "dst", "src", "off", "imm"])
@@ -522,15 +522,19 @@ class HashGlobalVar(Expression):
yield dst, False, self.signed
-
class HashGlobalVarDesc:
- def __init__(self, count, signed):
+ def __init__(self, count, signed, default=0):
self.count = count
self.signed = signed
+ self.default = default
def __get__(self, instance, owner):
if instance is None:
return self
+ if instance.loaded:
+ fd = instance.__dict__[self.name].fd
+ ret = bpf.lookup_elem(fd, pack("B", self.count), 4)
+ return unpack("i" if self.signed else "I", ret)[0]
ret = instance.__dict__.get(self.name, None)
if ret is None:
ret = HashGlobalVar(instance, self.count, self.signed)
@@ -541,6 +545,11 @@ class HashGlobalVarDesc:
self.name = name
def __set__(self, ebpf, value):
+ if ebpf.loaded:
+ fd = ebpf.__dict__[self.name].fd
+ bpf.update_elem(fd, pack("B", self.count),
+ pack("i" if self.signed else "I", value), 0)
+ return
with ebpf.get_stack(8) as stack:
with value.calculate(None, False, self.signed) as (src, _, _):
ebpf.append(Opcode.STX, 10, src, stack + 4, 0)
@@ -549,30 +558,38 @@ class HashGlobalVarDesc:
ebpf.r1 = ebpf.get_fd(ebpf.__dict__[self.name].fd)
ebpf.r2 = ebpf.r10 + stack
ebpf.r3 = ebpf.r10 + (stack + 4)
- ebpf.r4 = 3
+ ebpf.r4 = 0
ebpf.call(2)
-class HashMap:
+class Map:
+ def init(self, ebpf):
+ pass
+
+ def load(self, ebpf):
+ pass
+
+class HashMap(Map):
count = 0
def __init__(self):
self.vars = []
- def globalVar(self, signed=False):
+ def globalVar(self, signed=False, default=0):
self.count += 1
- ret = HashGlobalVarDesc(self.count, signed)
+ ret = HashGlobalVarDesc(self.count, signed, default)
self.vars.append(ret)
return ret
- def __set_name__(self, owner, name):
- owner._add_init_hook(self._init)
-
- def _init(self, ebpf):
- fd = create_map(1, 1, 4, self.count)
+ def init(self, ebpf):
+ fd = bpf.create_map(1, 1, 4, self.count)
for v in self.vars:
getattr(ebpf, v.name).fd = fd
+ def load(self, ebpf):
+ for v in self.vars:
+ setattr(ebpf, v.name, ebpf.__class__.__dict__[v.name].default)
+
class PseudoFd(Expression):
def __init__(self, ebpf, fd):
@@ -620,6 +637,7 @@ class EBPF:
self.prog_type = prog_type
self.license = license
self.kern_version = kern_version
+ self.loaded = False
self.m8 = MemoryDesc(self, Opcode.B)
self.m16 = MemoryDesc(self, Opcode.H)
@@ -628,9 +646,9 @@ class EBPF:
self.owners = {1, 10}
- if self._init_hooks is not None:
- for hook in self._init_hooks:
- hook(self)
+ for v in self.__class__.__dict__.values():
+ if isinstance(v, Map):
+ v.init(self)
def append(self, opcode, dst, src, off, imm):
self.opcodes.append(Instruction(opcode, dst, src, off, imm))
@@ -642,8 +660,15 @@ class EBPF:
for i in self.opcodes)
def load(self, log_level=0, log_size=4096):
- return prog_load(self.prog_type, self.assemble(), self.license,
- log_level, log_size, self.kern_version)
+ ret = bpf.prog_load(self.prog_type, self.assemble(), self.license,
+ log_level, log_size, self.kern_version)
+ self.loaded = True
+
+ for v in self.__class__.__dict__.values():
+ if isinstance(v, Map):
+ v.load(self)
+
+ return ret
def jumpIf(self, comp):
comp.compare(False)
@@ -717,13 +742,6 @@ class EBPF:
yield self.stack
self.stack = oldstack
- _init_hooks = None
-
- @classmethod
- def _add_init_hook(cls, hook):
- if cls._init_hooks is None:
- cls._init_hooks = []
- cls._init_hooks.append(hook)
for i in range(11):
setattr(EBPF, f"r{i}", RegisterDesc(i, True))
diff --git a/ebpf_test.py b/ebpf_test.py
index 3ee19d8..5484ac3 100644
--- a/ebpf_test.py
+++ b/ebpf_test.py
@@ -3,7 +3,7 @@ from unittest import TestCase, main
from . import ebpf
from .ebpf import (
AssembleError, EBPF, HashMap, Opcode, OpcodeFlags, Opcode as O, LocalVar)
-from .bpf import ProgType
+from .bpf import ProgType, prog_test_run
opcodes = list((v.value, v) for v in Opcode)
@@ -472,6 +472,21 @@ class Tests(TestCase):
class KernelTests(TestCase):
+ def test_hashmap(self):
+ class Global(EBPF):
+ map = HashMap()
+ a = map.globalVar(default=5)
+
+ e = Global(ProgType.XDP, "GPL")
+ e.a += 7
+ e.exit()
+
+ fd = e.load()
+ prog_test_run(fd, 1000, 1000, 0, 0, 1)
+ e.a *= 2
+ prog_test_run(fd, 1000, 1000, 0, 0, 1)
+ self.assertEqual(e.a, 31)
+
def test_minimal(self):
class Global(EBPF):
map = HashMap()
--
GitLab