From 92ad6a33bdebd1fc3a429483f07580e5e9abd2fc Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@xfel.eu>
Date: Tue, 18 Jun 2024 15:21:21 +0000
Subject: [PATCH] be a bit more defensive reading from netlink
---
ebpfcat/xdp.py | 37 ++++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)
diff --git a/ebpfcat/xdp.py b/ebpfcat/xdp.py
index 6837d0f..7064dca 100644
--- a/ebpfcat/xdp.py
+++ b/ebpfcat/xdp.py
@@ -25,7 +25,7 @@ from contextlib import asynccontextmanager, contextmanager
import os
from socket import AF_NETLINK, NETLINK_ROUTE, if_nametoindex
import socket
-from struct import pack, unpack
+from struct import pack, unpack_from
from .ebpf import EBPF, MemoryDesc
from .bpf import ProgType
@@ -86,21 +86,28 @@ class XDRFD(DatagramProtocol):
transport.sendto(p, (0, 0))
def datagram_received(self, data, addr):
- pos = 0
- while (pos < len(data)):
- ln, type, flags, seq, pid = unpack("IHHII", data[pos : pos+16])
- if type == 3: # DONE
- self.future.set_result(0)
- return
- elif type == 2: # ERROR
- errno, *args = unpack("iIHHII", data[pos+16 : pos+36])
- if errno != 0:
- self.future.set_exception(OSError(errno, os.strerror(-errno)))
+ try:
+ pos = 0
+ while (pos < len(data)):
+ ln, type, flags, seq, pid = unpack_from("IHHII", data, pos)
+ if type == 3: # DONE
+ self.future.set_result(0)
+ return
+ elif type == 2: # ERROR
+ errno, *args = unpack_from("iIHHII", data, pos + 16)
+ if errno != 0:
+ self.future.set_exception(
+ OSError(errno, os.strerror(-errno)))
+ return
+ if flags & 2 == 0: # not a multipart message
+ self.future.set_result(0)
return
- if flags & 2 == 0: # not a multipart message
- self.future.set_result(0)
- return
- pos += ln
+ pos += ln
+ self.future.set_exception(
+ RuntimeError("Netlink response not understood"))
+ except Exception as e:
+ self.future.set_exception(e)
+ raise
class PacketArray:
--
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