mirror of
https://github.com/54shady/kernel_drivers_examples.git
synced 2025-08-08 08:23:56 +00:00
129 lines
3.4 KiB
Markdown
129 lines
3.4 KiB
Markdown
# BPF samples
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## Using Ubuntu 22.04 as compilation setup
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[Ubuntu get source code](https://wiki.ubuntu.com/Kernel/SourceCode)
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[Ubuntu Build Your Own Kernel](https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel)
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安装必要的软件依赖
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apt install -y dpkg-dev
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apt-get build-dep linux linux-image-$(uname -r)
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在Docker中可以通过指定具体的版本来安装内核代码(比如5.15.0-57-generic)或者预先下载好代码
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apt-get build-dep linux linux-image-5.15.0-57-generic
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ubuntu解决安装包冲突问题
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apt-get install aptitude
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aptitude install <package-name>
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使用[Dockerfile](https://github.com/54shady/dfc/blob/master/bpf/Dockerfile)作为编译环境
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docker build . -t bpf2204 --build-arg x86/ubuntu:2204 --build-arg LAYOUTTOOL=pahole
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下载代码(等价于下面的git命令)到/usr/src/linux目录下
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apt-get -y source linux-image-unsigned-$(uname -r)
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==> git clone git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy
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cd /path/to/download/ubuntu/source
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ln -s $PWD /usr/src/linux
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cd /usr/src/linux
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直接将预先下载好的代码映射到docker中
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docker -v /path/to/linux:/usr/src/linux bpf2204 /bin/bash
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修改内核配置
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chmod +x scripts/*
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make clean
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make defconfig
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./scripts/config -e CONFIG_FTRACE
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./scripts/config -e CONFIG_DEBUG_INFO
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./scripts/config -e CONFIG_DEBUG_INFO_DWARF5
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./scripts/config -e CONFIG_BPF_SYSCALL
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./scripts/config -e CONFIG_DEBUG_INFO_BTF
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./scripts/config -d CONFIG_DEBUG_INFO_REDUCED
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yes "" | make oldconfig
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安装头文件到当前编译目录
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make headers_install
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编译内核
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make -j$(nproc) \
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KERNEL_DIR=/usr/src/linux \
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BPF_TOOLS_PATH=bpf_tools \
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BPF_EXAMPLES_PATH=bpf_examples \
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CC=/usr/bin/gcc
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编译内核自带的用例
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make M=samples/bpf
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或者在bpf目录编译
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cd /usr/src/linux/samples/bpf && make
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### 运行内核自带的用列
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在运行环境中挂载对应的文件系统
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mount -t bpf bpf /sys/fs/bpf
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create map and insert elm
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./fds_example -F /sys/fs/bpf/m -P -m -k 1 -v 42
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bpf: map fd:3 (Success)
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bpf: pin ret:(0,Success)
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bpf: fd:3 u->(1:42) ret:(0,Success)
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get elm
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./fds_example -F /sys/fs/bpf/m -G -m -k 1
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bpf: get fd:3 (Success)
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bpf: fd:3 l->(1):42 ret:(0,Success)
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update elm
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./fds_example -F /sys/fs/bpf/m -G -m -k 1 -v 24
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bpf: get fd:3 (Success)
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bpf: fd:3 u->(1:24) ret:(0,Success)
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get elm
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./fds_example -F /sys/fs/bpf/m -G -m -k 1
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bpf: get fd:3 (Success)
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bpf: fd:3 l->(1):24 ret:(0,Success)
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## 使用本demo(using docker to compile)
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将当前代码挂载到容器中
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docker -v $PWD:/code -v /path/to/linux:/usr/src/linux bpf /bin/bash
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在当前目录操作使用对应文件
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ln -s $PWD/demo_kern.c /usr/src/linux/samples/bpf
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ln -s $PWD/demo_user.c /usr/src/linux/samples/bpf
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mv /usr/src/linux/samples/bpf/Makefile /usr/src/linux/samples/bpf/Makefile-org
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ln -s $PWD/Makefile /usr/src/linux/samples/bpf
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在当前目录编译时指定kernel代码路径
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make KERNEL_DIR=/usr/src/linux clean
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make KERNEL_DIR=/usr/src/linux
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用file查看下编译输出文件(demo_user.o和demo_kern.o)
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demo_user.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped
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demo_kern.o: ELF 64-bit LSB relocatable, eBPF, version 1 (SYSV), with debug_info, not stripped
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- demo_kern.c中的文件是被编译成eBPF的二进制文件,是要被eBPF虚拟机执行的代码
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- demo_user.c是将eBPF二进制文件加载到内核的代码
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