From 23e2a80ccb5bbc1ed6c73ac669999af09afb4512 Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@xfel.eu>
Date: Mon, 18 Jan 2021 14:57:23 +0000
Subject: [PATCH] use register 9 for XDP packets by default
This is generally a good idea as the packet usually needs to be
addressed a lot and should not be overwritten by function calls.
this is not thoroughly tested.
---
ebpf_test.py | 12 ++++++------
xdp.py | 14 ++++++--------
2 files changed, 12 insertions(+), 14 deletions(-)
diff --git a/ebpf_test.py b/ebpf_test.py
index 88b36b1..50c8c1d 100644
--- a/ebpf_test.py
+++ b/ebpf_test.py
@@ -501,12 +501,12 @@ class Tests(TestCase):
with p.Else():
e.r3 = 77
self.assertEqual(e.opcodes, [
- Instruction(opcode=O.LD+O.W, dst=0, src=1, off=0, imm=0),
- Instruction(opcode=O.LD+O.W, dst=2, src=1, off=4, imm=0),
- Instruction(opcode=O.LD+O.W, dst=3, src=1, off=0, imm=0),
- Instruction(opcode=O.ADD+O.LONG, dst=3, src=0, off=0, imm=100),
- Instruction(opcode=O.REG+O.JLE, dst=2, src=3, off=2, imm=0),
- Instruction(opcode=O.REG+O.LD, dst=3, src=0, off=22, imm=0),
+ Instruction(opcode=O.LD+O.W, dst=9, src=1, off=0, imm=0),
+ Instruction(opcode=O.LD+O.W, dst=0, src=1, off=4, imm=0),
+ Instruction(opcode=O.LD+O.W, dst=2, src=1, off=0, imm=0),
+ Instruction(opcode=O.ADD+O.LONG, dst=2, src=0, off=0, imm=100),
+ Instruction(opcode=O.REG+O.JLE, dst=0, src=2, off=2, imm=0),
+ Instruction(opcode=O.REG+O.LD, dst=3, src=9, off=22, imm=0),
Instruction(opcode=O.JMP, dst=0, src=0, off=1, imm=0),
Instruction(opcode=O.MOV+O.LONG, dst=3, src=0, off=0, imm=77)])
diff --git a/xdp.py b/xdp.py
index fd48740..efc0998 100644
--- a/xdp.py
+++ b/xdp.py
@@ -95,18 +95,16 @@ class PacketSize:
@contextmanager
def __lt__(self, value):
e = self.ebpf
- with e.tmp:
- e.tmp = e.m32[e.r1]
- with e.If(e.m32[e.r1 + 4] < e.m32[e.r1] + value) as comp:
- yield Packet(e, comp, e.tmp.no)
+ e.r9 = e.m32[e.r1]
+ with e.If(e.m32[e.r1 + 4] < e.m32[e.r1] + value) as comp:
+ yield Packet(e, comp, 9)
@contextmanager
def __gt__(self, value):
e = self.ebpf
- with e.tmp:
- e.tmp = e.m32[e.r1]
- with e.If(e.m32[e.r1 + 4] > e.m32[e.r1] + value) as comp:
- yield Packet(e, comp, e.tmp.no)
+ e.r9 = e.m32[e.r1]
+ with e.If(e.m32[e.r1 + 4] > e.m32[e.r1] + value) as comp:
+ yield Packet(e, comp, 9)
def __le__(self, value):
return self < value + 1
--
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