Recent Posts

• 2023-03-05

  Tcpdump Deep Dive - How Tcpdump works in the kernel

  Background Network processing by the kernel Initialization RX side processing TX side processing ConclusionBackgroundWhile using Cilium, we have observed that in some cases, despite successful pinging, tcpdump fails to capture any packets...

• 2023-02-26

  Cilium Datapath Deep Dive 1 - Basic Connectivity

  Overview Backgroud Important BPF hook points Cilium Datapath pod to pod on the same node pod to pod on different nodes node to pod pod to service (clusterIP) pod to external Conclusion ReferenceOverviewWith the ...

• 2022-10-30

  tcpdump在内核中是如何工作的

  背景 内核对网络数据的处理 初始化 接收端处理 发送端处理 背景在使用Cilium的过程中，我们发现很多情况下看到流量已经打通，但使用tcpdump抓包却看不到任何包经过的痕迹。本文尝试对tcpdump在kernel中的工作过程一探究竟。内核对网络数据的处理在分析tcpdump的工作原理前，需要了解kernel对网络数据的处理过程。总体来说，当物理网卡(NIC)收到物理线路上的数据帧时 NIC以DMA方式把数据帧写入预先分配的ring buffer中 触发硬中断，通知CP...

• 2022-09-01

  Cilium数据平面深度解析 1 - 基础连通性

  总览 背景 重要的bpf hook points Cilium Datapath 同node上pod to pod 跨node的pod to pod node to pod pod to service (clusterIP) pod to external 总结 Reference总览随着bpf/ebpf技术的快速发展，Cilium被认为是Kubernetes生态中最有前景的网络方案。依靠着ebpf灵活、高效、功能和...

• 2022-08-30

  Things to do before we die!

  Travel Europe Changsha Chengdu Yellowstone National Park Antelope ValleyExperience Swim Skating Try Shaobing & Satang Get married Fly drones in more than 10 cities