{"id":29049,"date":"2024-11-07T15:54:14","date_gmt":"2024-11-07T07:54:14","guid":{"rendered":"https:\/\/www.yunshan.net\/blog\/?p=20533"},"modified":"2024-11-07T15:54:14","modified_gmt":"2024-11-07T07:54:14","slug":"%e6%8f%ad%e5%bc%80ebpf%e7%9a%84%e7%a5%9e%e7%a7%98%e9%9d%a2%e7%ba%b1%ef%bc%9a%e5%b7%a5%e4%bd%9c%e6%9c%ba%e5%88%b6%e5%85%a8%e8%a7%a3%e6%9e%90","status":"publish","type":"post","link":"https:\/\/www.yunshan.net\/blog\/archives\/29049.html","title":{"rendered":"\u63ed\u5f00eBPF\u7684\u795e\u79d8\u9762\u7eb1\uff1a\u5de5\u4f5c\u673a\u5236\u5168\u89e3\u6790"},"content":{"rendered":"

\t\t\t\teBPF<\/a>\uff08Extended Berkeley Packet Filter\uff09\u4f5c\u4e3a\u4e00\u79cd\u65b0\u5174\u7684\u6280\u672f\uff0c\u8fd1\u5e74\u6765\u5728Linux\u5185\u6838\u9886\u57df\u5f15\u8d77\u4e86\u5e7f\u6cdb\u5173\u6ce8\u3002\u5b83\u4e0d\u4ec5\u6781\u5927\u5730\u6269\u5c55\u4e86\u4f20\u7edfBPF\uff08Berkeley Packet Filter\uff09\u7684\u529f\u80fd\uff0c\u8fd8\u5728\u7f51\u7edc\u76d1\u63a7\u3001\u6027\u80fd\u5206\u6790\u3001\u5b89\u5168\u9632\u62a4\u7b49\u591a\u4e2a\u9886\u57df\u5c55\u73b0\u51fa\u5f3a\u5927\u7684\u6f5c\u529b\u3002\u672c\u6587\u5c06\u6df1\u5165\u63a2\u8ba8eBPF<\/a>\u7684\u5de5\u4f5c\u673a\u5236\uff0c\u63ed\u5f00\u5176\u795e\u79d8\u9762\u7eb1\u3002<\/p>\n\n\n\n\n

\u4e00\u3001eBPF\u7684\u8d77\u6e90\u4e0e\u53d1\u5c55<\/h3>\n\n\n\n\n

1.1 BPF\u7684\u8d77\u6e90<\/h4>\n\n\n\n\n

BPF\u6700\u521d\u7531Steven McCanne\u548cVan Jacobson\u57281992\u5e74\u63d0\u51fa\uff0c\u4e3b\u8981\u7528\u4e8e\u7f51\u7edc\u6570\u636e\u5305\u7684\u8fc7\u6ee4\u3002\u5176\u6838\u5fc3\u601d\u60f3\u662f\u901a\u8fc7\u4e00\u4e2a\u7b80\u5355\u7684\u865a\u62df\u673a\u5728\u5185\u6838\u4e2d\u6267\u884c\u8fc7\u6ee4\u7a0b\u5e8f\uff0c\u4ece\u800c\u9ad8\u6548\u5730\u5904\u7406\u7f51\u7edc\u6570\u636e\u5305\u3002\u65e9\u671f\u7684BPF\u4e3b\u8981\u7528\u4e8e\u7f51\u7edc\u76d1\u63a7\u5de5\u5177\u5982tcpdump\u3002<\/p>\n\n\n\n\n\n\n\n\n

<\/p>\n\n\n\n\n\n\n\n\n\n

1.2 eBPF\u7684\u8bde\u751f<\/h4>\n\n\n\n\n

\u968f\u7740\u6280\u672f\u7684\u53d1\u5c55\uff0cBPF\u7684\u5c40\u9650\u6027\u9010\u6e10\u663e\u73b0\uff0c\u5c24\u5176\u662f\u5728\u5904\u7406\u590d\u6742\u7f51\u7edc\u73af\u5883\u548c\u591a\u6837\u5316\u5e94\u7528\u573a\u666f\u65f6\u3002\u4e3a\u4e86\u514b\u670d\u8fd9\u4e9b\u9650\u5236\uff0cLinux\u793e\u533a\u57282014\u5e74\u5f15\u5165\u4e86eBPF\u3002eBPF\u4e0d\u4ec5\u6269\u5c55\u4e86BPF\u7684\u529f\u80fd\uff0c\u8fd8\u5f15\u5165\u4e86\u66f4\u591a\u7684\u6307\u4ee4\u96c6\u548c\u66f4\u5f3a\u5927\u7684\u6570\u636e\u5904\u7406\u80fd\u529b\u3002<\/p>\n\n\n\n\n

\u4e8c\u3001eBPF\u7684\u6838\u5fc3\u6982\u5ff5<\/h3>\n\n\n\n\n

2.1 eBPF\u7a0b\u5e8f<\/h4>\n\n\n\n\n

eBPF\u7a0b\u5e8f\u662f\u8fd0\u884c\u5728Linux\u5185\u6838\u4e2d\u7684\u5c0f\u578b\u4ee3\u7801\u7247\u6bb5\uff0c\u901a\u5e38\u7528C\u8bed\u8a00\u7f16\u5199\uff0c\u5e76\u901a\u8fc7eBPF\u7f16\u8bd1\u5668\u8f6c\u6362\u4e3aeBPF\u6307\u4ee4\u96c6\u3002\u8fd9\u4e9b\u7a0b\u5e8f\u53ef\u4ee5\u5728\u5185\u6838\u7684\u7279\u5b9a\u94a9\u5b50\u70b9\uff08\u5982\u7f51\u7edc\u6570\u636e\u5305\u5904\u7406\u3001\u7cfb\u7edf\u8c03\u7528\u7b49\uff09\u6267\u884c\uff0c\u5b9e\u73b0\u5bf9\u5185\u6838\u884c\u4e3a\u7684\u76d1\u63a7\u548c\u4fee\u6539\u3002<\/p>\n\n\n\n\n

2.2 eBPF maps<\/h4>\n\n\n\n\n

eBPF maps\u662feBPF\u7a0b\u5e8f\u7528\u4e8e\u5b58\u50a8\u548c\u68c0\u7d22\u6570\u636e\u7684\u952e\u503c\u5bf9\u6570\u636e\u7ed3\u6784\u3002\u5e38\u89c1\u7684eBPF maps\u7c7b\u578b\u5305\u62ec\u54c8\u5e0c\u8868\u3001\u6570\u7ec4\u3001\u73af\u5f62\u7f13\u51b2\u533a\u7b49\u3002\u901a\u8fc7maps\uff0ceBPF\u7a0b\u5e8f\u53ef\u4ee5\u5b9e\u73b0\u6570\u636e\u7684\u6301\u4e45\u5316\u548c\u5171\u4eab\u3002<\/p>\n\n\n\n\n

2.3 eBPF\u94a9\u5b50\u70b9<\/h4>\n\n\n\n\n

eBPF\u94a9\u5b50\u70b9\u662f\u5185\u6838\u4e2d\u9884\u5b9a\u4e49\u7684\u6267\u884c\u70b9\uff0ceBPF\u7a0b\u5e8f\u53ef\u4ee5\u6302\u8f7d\u5728\u8fd9\u4e9b\u70b9\u4e0a\uff0c\u4ee5\u4fbf\u5728\u7279\u5b9a\u4e8b\u4ef6\u53d1\u751f\u65f6\u6267\u884c\u3002\u5e38\u89c1\u7684\u94a9\u5b50\u70b9\u5305\u62ec\u7f51\u7edc\u6570\u636e\u5305\u5904\u7406\uff08\u5982XDP\u3001TC\uff09\u3001\u7cfb\u7edf\u8c03\u7528\uff08\u5982tracepoints\u3001kprobes\uff09\u7b49\u3002<\/p>\n\n\n\n\n

\u4e09\u3001eBPF\u7684\u5de5\u4f5c\u6d41\u7a0b<\/h3>\n\n\n\n\n

3.1 \u7f16\u5199eBPF\u7a0b\u5e8f<\/h4>\n\n\n\n\n

eBPF\u7a0b\u5e8f\u901a\u5e38\u4f7f\u7528C\u8bed\u8a00\u7f16\u5199\uff0c\u5229\u7528eBPF\u63d0\u4f9b\u7684API\u548c\u52a9\u624b\u51fd\u6570\uff08helpers\uff09\u6765\u5b9e\u73b0\u5177\u4f53\u529f\u80fd\u3002\u7f16\u5199\u5b8c\u6210\u540e\uff0c\u9700\u8981\u901a\u8fc7eBPF\u7f16\u8bd1\u5668\uff08\u5982Clang\/LLVM\uff09\u5c06C\u4ee3\u7801\u7f16\u8bd1\u4e3aeBPF\u6307\u4ee4\u96c6\u3002<\/p>\n\n\n\n\n

#include <linux\/bpf.h>
\n#include <bpf\/bpf_helpers.h>
\n
\nSEC("xdp")
\nint xdp_drop(struct xdp_md *ctx) {
\n    return XDP_DROP;
\n}
\n
\nchar _license[] SEC("license") = "GPL";
\n<\/code><\/pre>\n\n\n\n\n
3.2 \u52a0\u8f7d\u548c\u9a8c\u8bc1eBPF\u7a0b\u5e8f<\/h4>\n\n\n\n\n
\u7f16\u8bd1\u751f\u6210\u7684eBPF\u5bf9\u8c61\u6587\u4ef6\u901a\u8fc7\u7528\u6237\u7a7a\u95f4\u5de5\u5177\uff08\u5982bpftool\u3001libbpf\uff09\u52a0\u8f7d\u5230\u5185\u6838\u4e2d\u3002\u52a0\u8f7d\u8fc7\u7a0b\u4e2d\uff0c\u5185\u6838\u7684eBPF\u9a8c\u8bc1\u5668\u4f1a\u5bf9\u7a0b\u5e8f\u8fdb\u884c\u4e25\u683c\u7684\u5b89\u5168\u68c0\u67e5\uff0c\u786e\u4fdd\u5176\u4e0d\u4f1a\u5bf9\u7cfb\u7edf\u7a33\u5b9a\u6027\u9020\u6210\u5f71\u54cd\u3002<\/p>\n\n\n\n\n
\u9a8c\u8bc1\u5668\u7684\u4e3b\u8981\u68c0\u67e5\u5185\u5bb9\u5305\u62ec\uff1a<\/p>\n\n\n\n\n