{"id":8040,"date":"2023-12-08T16:56:11","date_gmt":"2023-12-08T08:56:11","guid":{"rendered":"https:\/\/yanjingang.com\/blog\/?p=8040"},"modified":"2023-12-13T20:54:46","modified_gmt":"2023-12-13T12:54:46","slug":"ebpf-map-%e6%95%b0%e6%8d%ae%e4%bc%a0%e9%80%92%e7%9a%84%e6%a1%a5%e6%a2%81","status":"publish","type":"post","link":"https:\/\/yanjingang.com\/blog\/?p=8040","title":{"rendered":"eBPF Map\u2014\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u6570\u636e\u4f20\u9012\u7684\u6865\u6881"},"content":{"rendered":"<p>\u4e0a\u4e00\u6b21\uff0c\u6211\u4eec\u5bf9eBPF\u6709\u4e86\u57fa\u672c\u7684\u4e86\u89e3\uff0c\u5e76\u5b9e\u73b0\u4e86\u4e00\u4e2a\u7b80\u5355\u7684kprobe\u76d1\u542c\u3002\u672c\u6587\u6211\u4eec\u4eceBPF Map\u5f00\u59cb\uff0c\u4e86\u89e3\u5982\u4f55\u5c06\u5728\u5185\u6838\u4e2d\u6293\u53d6\u5230\u7684\u6570\u636e\u4f20\u9012\u5230\u7528\u6237\u7a7a\u95f4\u3002\u4e86\u89e3BPF Map\u662f\u4ece0\u5f00\u59cb\u72ec\u7acb\u7f16\u5199\u4e00\u4e2aeBPF\u7a0b\u5e8f\u7684\u5fc5\u7ecf\u4e4b\u8def\u3002<\/p>\n<h1>\u4e00\u3001\u6982\u8ff0<\/h1>\n<p><a href=\"https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow.png\"><img loading=\"lazy\" class=\"alignnone size-large wp-image-8043\" src=\"https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-1024x570.png\" alt=\"\" width=\"625\" height=\"348\" srcset=\"https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-1024x570.png 1024w, https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-300x167.png 300w, https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-768x427.png 768w, https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-1536x855.png 1536w, https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-2048x1140.png 2048w, https:\/\/yanjingang.com\/blog\/wp-content\/uploads\/2023\/12\/ebpfworkflow-624x347.png 624w\" sizes=\"(max-width: 625px) 100vw, 625px\" \/><\/a><\/p>\n<h4>1.BPF Map\u662f\u4ec0\u4e48<\/h4>\n<p>\u5982\u4e0a\u56fe\uff0c\u7b80\u5355\u6765\u8bf4\uff0cBPF Map\u5c31\u662f\u5185\u6838\u7a7a\u95f4\u548c\u7528\u6237\u7a7a\u95f4\u4e4b\u95f4\u7528\u4e8e\u6570\u636e\u4ea4\u6362\u3001\u4fe1\u606f\u4f20\u9012\u7684\u6865\u6881\u3002\u662feBPF\u7a0b\u5e8f\u4e2d\u4f7f\u7528\u7684\u4e3b\u8981\u6570\u636e\u7ed3\u6784\u3002<\/p>\n<p>BPF Map\u672c\u8d28\u4e0a\u662f\u4ee5\u300c\u952e\/\u503c\u300d\u65b9\u5f0f\u5b58\u50a8\u5728\u5185\u6838\u4e2d\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5b83\u4eec\u53ef\u4ee5\u88ab\u4efb\u4f55\u77e5\u9053\u5b83\u4eec\u7684BPF\u7a0b\u5e8f\u8bbf\u95ee\u3002<\/p>\n<p>\u5728\u5185\u6838\u7a7a\u95f4\u7684\u7a0b\u5e8f\u521b\u5efaBPF Map\u5e76\u8fd4\u56de\u5bf9\u5e94\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u5728\u7528\u6237\u7a7a\u95f4\u8fd0\u884c\u7684\u7a0b\u5e8f\u5c31\u53ef\u4ee5\u901a\u8fc7\u8fd9\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u6765\u8bbf\u95ee\u5e76\u64cd\u4f5cBPF Map\uff0c\u4ece\u800c\u5b9e\u73b0kernel\u5185\u6838\u7a7a\u95f4\u4e0euser\u7528\u6237\u7a7a\u95f4\u7684\u6570\u636e\u4ea4\u6362\u3002<\/p>\n<h4>2. BPF Map\u6570\u636e\u7ed3\u6784<\/h4>\n<p>\u6bcf\u4e2aBPF Map\u7531\u56db\u4e2a\u503c\u5b9a\u4e49\uff1a\u7c7b\u578b\u3001\u5143\u7d20\u7684\u6700\u5927\u4e2a\u6570\u3001\u503c\u5927\u5c0f(\u4ee5\u5b57\u8282\u4e3a\u5355\u4f4d)\u548c\u952e\u5927\u5c0f(\u4ee5\u5b57\u8282\u4e3a\u5355\u4f4d)<\/p>\n<pre class=\"pure-highlightjs\"><code class=\"\"># BPF Map \u5b9a\u4e49\u793a\u4f8b\r\nstruct {\r\n\t__uint(type, BPF_MAP_TYPE_HASH);   \/\/ \u7c7b\u578b\r\n\t__uint(max_entries, 8192);         \/\/ \u5143\u7d20\u7684\u6700\u5927\u4e2a\u6570\r\n\t__type(key, pid_t);                \/\/ \u952e\u5927\u5c0f(\u4ee5\u5b57\u8282\u4e3a\u5355\u4f4d)\r\n\t__type(value, u64);                \/\/ \u503c\u5927\u5c0f(\u4ee5\u5b57\u8282\u4e3a\u5355\u4f4d)\r\n} rb SEC(\".maps\");     \/\/ SEC(\".maps\") \u58f0\u660e\u5e76\u521b\u5efa\u4e86\u4e00\u4e2a\u540d\u4e3arb\u7684BPFMap<\/code><\/pre>\n<h1><\/h1>\n<h1>\u4e8c\u3001BPF Map\u7c7b\u578b<\/h1>\n<h4>1. bpf_map_type\u7c7b\u578b\u5b9a\u4e49\u5168\u96c6<\/h4>\n<p>\u6240\u6709 map \u7c7b\u578b\u7684\u5b9a\u4e49\uff1a<\/p>\n<div class=\"language-c highlighter-rouge\">\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"c1\">\/\/ https:\/\/github.com\/torvalds\/linux\/blob\/v5.10\/include\/uapi\/linux\/bpf.h#L130<\/span>\r\n\r\n<span class=\"k\">enum<\/span> <span class=\"n\">bpf_map_type<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_UNSPEC<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_HASH<\/span><span class=\"p\">,             \/\/ \u4e00\u79cd\u54c8\u5e0c\u8868<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_ARRAY<\/span><span class=\"p\">,            \/\/ \u4e00\u79cd\u4e3a\u5feb\u901f\u67e5\u627e\u901f\u5ea6\u800c\u4f18\u5316\u7684\u6570\u7ec4\u7c7b\u578bmap\u952e\u503c\u5bf9\uff0c\u901a\u5e38\u7528\u4e8e\u8ba1\u6570\u5668<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_PROG_ARRAY<\/span><span class=\"p\">,       \/\/ \u4e0eeBPF\u7a0b\u5e8f\u76f8\u5bf9\u5e94\u7684\u4e00\u79cd\u6587\u4ef6\u63cf\u8ff0\u7b26\u6570\u7ec4;\u7528\u4e8e\u5b9e\u73b0\u8df3\u8f6c\u8868\u548c\u5904\u7406\u7279\u5b9a\uff08\u7f51\u7edc\uff09\u5305\u534f\u8bae\u7684\u5b50\u7a0b\u5e8f<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_PERF_EVENT_ARRAY<\/span><span class=\"p\">, \/\/ \u5b58\u50a8\u6307\u5411perf_event\u6570\u636e\u7ed3\u6784\u7684\u6307\u9488\uff0c\u7528\u4e8e\u8bfb\u53d6\u548c\u5b58\u50a8perf\u4e8b\u4ef6\u8ba1\u6570\u5668<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_PERCPU_HASH<\/span><span class=\"p\">,      \/\/ \u4e00\u79cd\u57fa\u4e8e\u6bcf\u4e2aCPU\u7684\u54c8\u5e0c\u8868<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_PERCPU_ARRAY<\/span><span class=\"p\">,     \/\/ \u4e00\u79cd\u57fa\u4e8e\u6bcf\u4e2acpu\u7684\u6570\u7ec4\uff0c\u7528\u4e8e\u5b9e\u73b0\u5c55\u73b0\u5ef6\u8fdf\u7684\u76f4\u65b9\u56fe<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_STACK_TRACE<\/span><span class=\"p\">,      \/\/ \u5b58\u50a8\u5806\u6808\u8ddf\u8e2a\u4fe1\u606f<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_CGROUP_ARRAY<\/span><span class=\"p\">,     \/\/ \u5b58\u50a8\u6307\u5411\u63a7\u5236\u7ec4\u7684\u6307\u9488<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_LRU_HASH<\/span><span class=\"p\">,         \/\/ \u4e00\u79cd\u53ea\u4fdd\u7559\u6700\u8fd1\u4f7f\u7528\u9879\u7684\u54c8\u5e0c\u8868<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_LRU_PERCPU_HASH<\/span><span class=\"p\">,  \/\/ \u4e00\u79cd\u57fa\u4e8e\u6bcf\u4e2aCPU\u7684\u54c8\u5e0c\u8868\uff0c\u53ea\u4fdd\u7559\u6700\u8fd1\u4f7f\u7528\u9879<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_LPM_TRIE<\/span><span class=\"p\">,         \/\/ \u4e00\u4e2a\u5339\u914d\u6700\u957f\u524d\u7f00\u7684\u5b57\u5178\u6811\u6570\u636e\u7ed3\u6784\uff0c\u9002\u7528\u4e8e\u5c06IP\u5730\u5740\u5339\u914d\u5230\u4e00\u4e2a\u8303\u56f4<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_ARRAY_OF_MAPS<\/span><span class=\"p\">,    \/\/ \u4e00\u79cdmap-in-map\u6570\u636e\u7ed3\u6784<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_HASH_OF_MAPS<\/span><span class=\"p\">,     \/\/ \u4e00\u79cdmap-in-map\u6570\u636e\u7ed3\u6784<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_DEVMAP<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_SOCKMAP<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_CPUMAP<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_XSKMAP<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_SOCKHASH<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_CGROUP_STORAGE<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_REUSEPORT_SOCKARRAY<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_QUEUE<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_STACK<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_SK_STORAGE<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_DEVMAP_HASH<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_STRUCT_OPS<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_RINGBUF<\/span><span class=\"p\">,          \/\/ \u4e00\u79cd\u9ad8\u6027\u80fd\u5b57\u8282\u5f62\u7f13\u51b2\u533a<\/span>\r\n    <span class=\"n\">BPF_MAP_TYPE_INODE_STORAGE<\/span><span class=\"p\">,<\/span>\r\n\r\n<span class=\"p\">};<\/span><\/code><\/pre>\n<\/div>\n<\/div>\n<p>\u6ce8\uff1a\u00a0bcc\u00a0<a href=\"https:\/\/github.com\/iovisor\/bcc\/blob\/master\/docs\/kernel-versions.md#tables-aka-maps\">\u7ef4\u62a4\u7684\u6587\u6863<\/a>\uff0c \u8bb0\u5f55\u4e86\u54ea\u4e2a\u5185\u6838\u7248\u672c\u5f15\u5165\u7684\uff0c\u4ee5\u53ca\u5bf9\u5e94\u7684 patch\u3002<\/p>\n<p>&nbsp;<\/p>\n<h4>2. Hash Maps<\/h4>\n<p>Hash map \u7684\u5b9e\u73b0\u89c1\u00a0<a href=\"https:\/\/github.com\/torvalds\/linux\/blob\/v5.8\/kernel\/bpf\/hashtab.c\">kernel\/bpf\/hashtab.c<\/a>\u3002 \u4e94\u79cd\u7c7b\u578b\u5171\u7528\u4e00\u5957\u4ee3\u7801\uff1a<\/p>\n<ul>\n<li><code class=\"language-plaintext highlighter-rouge\">BPF_MAP_TYPE_HASH<\/code><\/li>\n<li><code class=\"language-plaintext highlighter-rouge\">BPF_MAP_TYPE_PERCPU_HASH<\/code><\/li>\n<li><code class=\"language-plaintext highlighter-rouge\">BPF_MAP_TYPE_LRU_HASH<\/code><\/li>\n<li><code class=\"language-plaintext highlighter-rouge\">BPF_MAP_TYPE_LRU_PERCPU_HASH<\/code><\/li>\n<li><code class=\"language-plaintext highlighter-rouge\">BPF_MAP_TYPE_HASH_OF_MAPS<\/code><\/li>\n<\/ul>\n<p>Hash map \u7684\u7279\u70b9\uff1a<\/p>\n<ul>\n<li><span style=\"color: #ff0000;\">key \u7684\u957f\u5ea6\u6ca1\u6709\u9650\u5236<\/span>\u3002<\/li>\n<li>\u7ed9\u5b9a key \u67e5\u627e value \u65f6\uff0c\u5185\u90e8\u901a\u8fc7\u54c8\u5e0c\u5b9e\u73b0\uff0c\u800c\u975e\u6570\u7ec4\u7d22\u5f15\u3002 <span style=\"color: #ff0000;\">key\/value \u662f\u53ef\u5220\u9664\u7684<\/span>\uff1b\u4f5c\u4e3a\u5bf9\u6bd4\uff0c<span style=\"color: #ff0000;\">Array \u7c7b\u578b\u7684 map \u4e2d\uff0ckey\/value \u662f\u4e0d\u53ef\u5220\u9664\u7684<\/span>\uff08\u4f46\u7528\u7a7a\u503c\u8986\u76d6\u6389 value \uff0c\u53ef\u5b9e\u73b0\u5220\u9664\u6548\u679c\uff09\u3002\u539f\u56e0\u5176\u5b9e\u4e5f\u5f88\u7b80\u5355\uff1a\u54c8\u5e0c\u8868\u662f\u94fe\u8868\uff0c\u53ef\u4ee5\u5220\u9664\u94fe\u8868\u4e2d\u7684\u5143\u7d20\uff1barray \u662f\u5185\u5b58\u7a7a\u95f4\u8fde\u7eed\u7684\u6570\u7ec4\uff0c\u5373\u4f7f\u67d0\u4e2a index \u5904\u7684 value \u4e0d\u7528\u4e86\uff0c\u8fd9\u6bb5\u5185\u5b58\u533a\u57df\u8fd8\u662f\u5f97\u7559\u7740\uff0c\u4e0d\u53ef\u80fd\u5c06\u5176\u91ca\u653e\u6389\u3002<\/li>\n<\/ul>\n<p>\u4e0d\u5e26\u4e0e\u5e26\u00a0<code class=\"language-plaintext highlighter-rouge\">PERCPU<\/code>\u00a0\u7684 map \u7684\u533a\u522b\uff1a<\/p>\n<ul>\n<li>\u524d\u8005\u662f global \u7684\uff0c\u53ea\u6709\u4e00\u4e2a\u5b9e\u4f8b\uff1b\u540e\u8005\u662f cpu-local \u7684\uff0c\u6bcf\u4e2a CPU \u4e0a\u90fd\u6709\u4e00\u4e2a map \u5b9e\u4f8b\uff1b<\/li>\n<li><span style=\"color: #ff0000;\">\u591a\u6838\u5e76\u53d1\u8bbf\u95ee\u65f6\uff0cglobal map \u8981\u52a0\u9501<\/span>\uff1b<span style=\"color: #ff0000;\">per-cpu map \u65e0\u9700\u52a0\u9501<\/span>\uff0c\u6bcf\u4e2a\u6838\u4e0a\u7684\u7a0b\u5e8f\u8bbf\u95ee local-cpu \u4e0a\u7684 map\uff1b\u6700\u540e\u5c06\u6240\u6709 CPU \u4e0a\u7684 map \u6c47\u603b\u3002<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">2.1 BPF_MAP_TYPE_HASH<\/h6>\n<p>\u6700\u7b80\u5355\u7684\u54c8\u5e0c map\u3002<\/p>\n<p>\u521d\u59cb\u5316\u65f6\u9700\u8981\u6307\u5b9a<span style=\"color: #ff0000;\">\u652f\u6301\u7684\u6700\u5927\u6761\u76ee\u6570<\/span>\uff08max_entries\uff09\u3002 \u6ee1\u4e86\u4e4b\u540e\u7ee7\u7eed\u63d2\u5165\u6570\u636e\u65f6\uff0c\u4f1a\u62a5\u00a0E2BIG\u00a0\u9519\u8bef\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00\u5c06\u5185\u6838\u6001\u5f97\u5230\u7684\u6570\u636e\u4f20\u9012\u7ed9\u7528\u6237\u6001\u7a0b\u5e8f\">\u573a\u666f\u4e00\uff1a\u5c06\u5185\u6838\u6001\u5f97\u5230\u7684\u6570\u636e\uff0c\u4f20\u9012\u7ed9\u7528\u6237\u6001\u7a0b\u5e8f\n<ul>\n<li>\u8fd9\u662f\u975e\u5e38\u5178\u578b\u7684\u5728<span style=\"color: #ff0000;\">\u5185\u6838\u6001\u548c\u7528\u6237\u6001\u4f20\u9012\u6570\u636e<\/span>\u573a\u666f\u3002<\/li>\n<li>\u4f8b\u5982\uff0cBPF \u7a0b\u5e8f\u8fc7\u6ee4\u7f51\u7edc\u8bbe\u5907\u8bbe\u5907\u4e0a\u7684\u5305\uff0c\u7edf\u8ba1\u6d41\u91cf\u4fe1\u606f\uff0c\u5e76\u5c06\u5176\u5199\u5230 map\u3002 \u7528\u6237\u6001\u7a0b\u5e8f\u4ece map \u8bfb\u53d6\u7edf\u8ba1\uff0c\u505a\u540e\u7eed\u5904\u7406\u3002<\/li>\n<\/ul>\n<\/li>\n<li id=\"\u573a\u666f\u4e8c\u5b58\u653e\u5168\u5c40\u914d\u7f6e\u4fe1\u606f\u4f9b-bpf-\u7a0b\u5e8f\u4f7f\u7528\">\u573a\u666f\u4e8c\uff1a\u5b58\u653e\u5168\u5c40\u914d\u7f6e\u4fe1\u606f\uff0c\u4f9b BPF \u7a0b\u5e8f\u4f7f\u7528\n<ul>\n<li>\u4f8b\u5982\uff0c\u5bf9\u4e8e\u9632\u706b\u5899\u529f\u80fd\u7684 BPF \u7a0b\u5e8f\uff0c\u5c06\u8fc7\u6ee4\u89c4\u5219\u653e\u5230 map \u91cc\u3002\u7528\u6237\u6001\u63a7\u5236\u7a0b\u5e8f\u901a\u8fc7 bpftool \u4e4b\u7c7b\u7684\u5de5\u5177\u66f4\u65b0 map \u91cc\u7684\u914d\u7f6e\u4fe1\u606f\uff0cBPF \u7a0b\u5e8f\u52a8\u6001\u52a0\u8f7d\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li>\u5c06\u5185\u6838\u6001\u6570\u636e\u4f20\u9012\u5230\u7528\u6237\u6001\uff1a<code class=\"language-plaintext highlighter-rouge\">samples\/bpf\/sockex2<\/code><\/li>\n<li>\u8fd9\u4e2a\u4f8b\u5b50\u7528 BPF \u7a0b<span style=\"color: #333333;\">\u5e8f\u00a0\u8fc7\u6ee4\u7f51\u7edc\u8bbe\u5907\u8bbe\u5907\u4e0a\u7684\u5305<\/span>\uff0c\u7edf\u8ba1\u5305\u6570\u548c\u5b57\u8282\u6570\uff0c \u5e76\u4ee5\u76ee\u7684 IP \u5730\u5740\u4e3a key \u5c06\u7edf\u8ba1\u4fe1\u606f\u5199\u5230 map\uff1a<\/li>\n<\/ul>\n<pre class=\"pure-highlightjs\"><code class=\"\">\/\/ samples\/bpf\/sockex2_kern.c\r\n\r\nstruct {\r\n    __uint(type, BPF_MAP_TYPE_HASH);  \/\/ BPF map \u7c7b\u578b\r\n    __uint(max_entries, 1024);        \/\/ \u6700\u5927 entry \u6570\u91cf\r\n    __type(key, __be32);              \/\/ \u76ee\u7684 IP \u5730\u5740\r\n    __type(value, struct pair);       \/\/ \u5305\u6570\u548c\u5b57\u8282\u6570\r\n} hash_map SEC(\".maps\");\r\n\r\nSEC(\"socket2\")\r\nint bpf_prog2(struct __sk_buff *skb)\r\n{\r\n    flow_dissector(skb, &amp;flow);\r\n\r\n    key = flow.dst; \/\/ \u76ee\u7684 IP \u5730\u5740\r\n    value = <span style=\"color: #ff0000;\">bpf_map_lookup_elem<\/span>(&amp;hash_map, &amp;key);\r\n    if (value) {    \/\/ \u5982\u679c\u5df2\u7ecf\u5b58\u5728\uff0c\u5219\u66f4\u65b0\u76f8\u5e94\u8ba1\u6570\r\n        <span style=\"color: #ff0000;\">__sync_fetch_and_add<\/span>(&amp;value-&gt;packets, 1);\r\n        __sync_fetch_and_add(&amp;value-&gt;bytes, skb-&gt;len);\r\n    } else {        \/\/ \u5426\u5219\uff0c\u65b0\u5efa\u4e00\u4e2a entry\r\n        struct pair val = {1, skb-&gt;len};\r\n        <span style=\"color: #ff0000;\">bpf_map_update_elem<\/span>(&amp;hash_map, &amp;key, &amp;val, BPF_ANY);\r\n    }\r\n    return 0;\r\n}<\/code><\/pre>\n<h6 id=\"1-bpf_map_type_hash\">2.2 BPF_MAP_TYPE_PERCPU_HASH<\/h6>\n<p id=\"\u4f7f\u7528\u573a\u666f-1\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li>\u57fa\u672c\u540c\u4e0a\u3002<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-1\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li>samples\/bpf\/map_perf_test_kern.c<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">2.3 BPF_MAP_TYPE_LRU_HASH<\/h6>\n<p>\u666e\u901a hash map \u7684\u95ee\u9898\u662f\u6709\u5927\u5c0f\u9650\u5236\uff0c\u8d85\u8fc7\u6700\u5927\u6570\u91cf\u540e\u65e0\u6cd5\u518d\u63d2\u5165\u4e86\u3002LRU map \u53ef\u4ee5\u907f \u514d\u8fd9\u4e2a\u95ee\u9898\uff0c<span style=\"color: #ff0000;\">\u5982\u679c map \u6ee1\u4e86\uff0c\u518d\u63d2\u5165\u65f6\u5b83\u4f1a\u81ea\u52a8\u5c06\u6700\u4e45\u672a\u88ab\u4f7f\u7528\uff08least recently used\uff09\u7684 entry \u4ece map \u4e2d\u79fb\u9664<\/span>\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-2\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00\u8fde\u63a5\u8ddf\u8e2aconntrack\u8868nat-\u8868\u7b49\u56fa\u5b9a\u5927\u5c0f\u54c8\u5e0c\u8868\">\u573a\u666f\u4e00\uff1a\u8fde\u63a5\u8ddf\u8e2a\uff08conntrack\uff09\u8868\u3001NAT \u8868\u7b49\u56fa\u5b9a\u5927\u5c0f\u54c8\u5e0c\u8868\n<ul>\n<li>\u6ee1\u4e86\u4e4b\u540e\u6700\u8001\u7684 entry \u4f1a\u88ab\u8e22\u51fa\u53bb\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-2\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li>samples\/bpf\/map_perf_test_kern.c<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">2.4 BPF_MAP_TYPE_LRU_PERCPU_HASH<\/h6>\n<p>\u57fa\u672c\u540c\u4e0a\u3002<\/p>\n<h6 id=\"1-bpf_map_type_hash\">2.5 BPF_MAP_TYPE_HASH_OF_MAPS<\/h6>\n<p>map-in-map\uff1a<span style=\"color: #ff0000;\">\u7b2c\u4e00\u4e2a map \u5185\u7684\u5143\u7d20\u662f\u6307\u5411\u53e6\u4e00\u4e2a map \u7684\u6307\u9488<\/span>\u3002 \u4e0e\u540e\u9762\u5c06\u4ecb\u7ecd\u7684\u00a0BPF_MAP_TYPE_ARRAY_OF_MAPS\u00a0\u7c7b\u4f3c\uff0c\u4f46\u5916\u5c42 map \u4f7f\u7528\u7684\u662f\u54c8\u5e0c\u800c\u4e0d\u662f\u6570\u7ec4\u3002<\/p>\n<p>\u53ef\u4ee5\u5c06\u00a0<span style=\"color: #ff0000;\">\u6574\u4e2a\uff08\u5185\u5c42\uff09map \u5728\u8fd0\u884c\u65f6\u5b9e\u73b0\u539f\u5b50\u66ff\u6362<\/span>\u3002<\/p>\n<p>\u76f8\u5173\u00a0<a href=\"https:\/\/www.mail-archive.com\/netdev@vger.kernel.org\/msg159383.html\">commit message<\/a>\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-3\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00map-in-map\">map-in-map\n<ul>\n<li>Array of array<\/li>\n<li>Hash of array<\/li>\n<li>Hash of hash<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-3\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li id=\"1-samplesbpftest_map_in_map_kernc\">samples\/bpf\/test_map_in_map_kern.c<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h4>3. Array Maps<\/h4>\n<h6 id=\"1-bpf_map_type_hash\">3.1 BPF_MAP_TYPE_ARRAY<\/h6>\n<p>\u6700\u5927\u7684\u7279\u70b9\uff1a<span style=\"color: #ff0000;\">key \u5c31\u662f\u6570\u7ec4\u4e2d\u7684\u7d22\u5f15\uff08index\uff09<\/span>\uff08\u56e0\u6b64 key\u4e00\u5b9a\u662f\u6574\u5f62\uff09\uff0c\u56e0\u6b64\u65e0\u9700\u5bf9key\u8fdb\u884c\u54c8\u5e0c\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666fkey-\u662f\u6574\u5f62\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li>key \u662f\u6574\u5f62<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-4\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li>\u6839\u636e\u534f\u8bae\u7c7b\u578b\uff08proto as key\uff09\u7edf\u8ba1\u6d41\u91cf\uff1a<code class=\"language-plaintext highlighter-rouge\">samples\/bpf\/sockex1<\/code><\/li>\n<\/ul>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"c1\">\/\/ samples\/bpf\/sockex1_kern.c<\/span>\r\n\r\n<span class=\"k\">struct<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">__uint<\/span><span class=\"p\">(<\/span><span class=\"n\">type<\/span><span class=\"p\">,<\/span> <span class=\"n\">BPF_MAP_TYPE_ARRAY<\/span><span class=\"p\">);\r\n    <span class=\"n\">__uint<\/span>(<span class=\"n\">max_entries<\/span>, <span class=\"mi\">256<\/span>);<\/span>\r\n    <span class=\"n\">__type<\/span><span class=\"p\">(<\/span><span class=\"n\">key<\/span><span class=\"p\">,<\/span> <span class=\"n\">u32<\/span><span class=\"p\">);<\/span>          <span class=\"c1\">\/\/ L4 \u534f\u8bae\u7c7b\u578b\uff08\u957f\u5ea6\u662f uint8\uff09\uff0c\u4f8b\u5982 IPPROTO_TCP\uff0c\u8303\u56f4\u662f 0~255<\/span>\r\n    <span class=\"n\">__type<\/span><span class=\"p\">(<\/span><span class=\"n\">value<\/span><span class=\"p\">,<\/span> <span class=\"kt\">long<\/span><span class=\"p\">);<\/span>       <span class=\"c1\">\/\/ \u7d2f\u8ba1\u5305\u957f\uff08skb-&gt;len\uff09<\/span>\r\n<span class=\"p\">}<\/span> <span class=\"n\">my_map<\/span> <span class=\"nf\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\".maps\"<\/span><span class=\"p\">);<\/span>\r\n\r\n<span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"socket1\"<\/span><span class=\"p\">)<\/span>\r\n<span class=\"kt\">int<\/span> <span class=\"nf\">bpf_prog1<\/span><span class=\"p\">(<\/span><span class=\"k\">struct<\/span> <span class=\"n\">__sk_buff<\/span> <span class=\"o\">*<\/span><span class=\"n\">skb<\/span><span class=\"p\">)<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"kt\">int<\/span> <span class=\"n\">index<\/span> <span class=\"o\">=<\/span> <span class=\"n\">load_byte<\/span><span class=\"p\">(<\/span><span class=\"n\">skb<\/span><span class=\"p\">,<\/span> <span class=\"n\">ETH_HLEN<\/span> <span class=\"o\">+<\/span> <span class=\"n\">offsetof<\/span><span class=\"p\">(<\/span><span class=\"k\">struct<\/span> <span class=\"n\">iphdr<\/span><span class=\"p\">,<\/span> <span class=\"n\">protocol<\/span><span class=\"p\">));<\/span> <span class=\"c1\">\/\/ L4 \u534f\u8bae\u7c7b\u578b<\/span>\r\n\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"n\">skb<\/span><span class=\"o\">-&gt;<\/span><span class=\"n\">pkt_type<\/span> <span class=\"o\">!=<\/span> <span class=\"n\">PACKET_OUTGOING<\/span><span class=\"p\">)<\/span>\r\n        <span class=\"k\">return<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span>\r\n\r\n    <span class=\"c1\">\/\/ \u6ce8\u610f\uff1a\u5728\u7528\u6237\u6001\u7a0b\u5e8f\u548c\u8fd9\u6bb5 BPF \u7a0b\u5e8f\u91cc\u90fd\u6ca1\u6709\u5f80 my_map \u91cc\u63d2\u5165\u6570\u636e\uff1b<\/span>\r\n    <span class=\"c1\">\/\/   * \u5982\u679c\u8fd9\u662f hash map \u7c7b\u578b\uff0c\u90a3\u4e0b\u9762\u7684 lookup \u4e00\u5b9a\u5931\u8d25\uff0c\u56e0\u4e3a\u6211\u4eec\u6ca1\u63d2\u5165\u8fc7\u4efb\u4f55\u6570\u636e\uff1b<\/span>\r\n    <span class=\"c1\">\/\/   * \u4f46\u8fd9\u91cc\u662f array \u7c7b\u578b\uff0c\u800c\u4e14 index \u8868\u793a\u7684 L4 \u534f\u8bae\u7c7b\u578b\uff0c\u5728 IP \u5934\u91cc\u5360\u4e00\u4e2a\u5b57\u8282\uff0c\u56e0\u6b64\u8303\u56f4\u5728 255 \u4ee5\u5185\uff1b<\/span>\r\n    <span class=\"c1\">\/\/     \u53c8 map \u7684\u957f\u5ea6\u58f0\u660e\u4e3a 256\uff0c\u6240\u4ee5\u8fd9\u91cc\u7684 lookup \u4e00\u5b9a\u80fd\u5b9a\u4f4d\u5230 array \u7684\u67d0\u4e2a\u4f4d\u7f6e\uff0c\u5373\u67e5\u627e\u4e00\u5b9a\u6210\u529f\u3002<\/span>\r\n    <span class=\"n\">value<\/span> <span class=\"o\">=<\/span> <span class=\"n\">bpf_map_lookup_elem<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">my_map<\/span><span class=\"p\">,<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">index<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"n\">value<\/span><span class=\"p\">)<\/span>\r\n        <span class=\"n\">__sync_fetch_and_add<\/span><span class=\"p\">(<\/span><span class=\"n\">value<\/span><span class=\"p\">,<\/span> <span class=\"n\">skb<\/span><span class=\"o\">-&gt;<\/span><span class=\"n\">len<\/span><span class=\"p\">);<\/span>\r\n\r\n    <span class=\"k\">return<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<\/div>\n<h6 id=\"1-bpf_map_type_hash\">3.2 BPF_MAP_TYPE_PERCPU_ARRAY<\/h6>\n<p>\u57fa\u672c\u540c\u4e0a\u3002<\/p>\n<h6 id=\"1-bpf_map_type_hash\">3.3 BPF_MAP_TYPE_PROG_ARRAY<\/h6>\n<p>\u7a0b\u5e8f\u6570\u7ec4\uff0c\u5c3e\u8c03\u7528 bpf_tail_call()\u00a0\u65f6\u4f1a\u7528\u5230\u3002<\/p>\n<ul>\n<li>key\uff1a\u4efb\u610f\u6574\u5f62\uff08\u56e0\u4e3a\u8981\u4f5c\u4e3a array index\uff09\uff0c\u5177\u4f53\u8868\u793a\u4ec0\u4e48\u7531\u4f7f\u7528\u8005\u8bbe\u8ba1\uff08\u4f8b\u5982\u8868\u793a\u534f\u8bae\u7c7b\u578b proto\uff09\u3002<\/li>\n<li>value\uff1a<span style=\"color: #ff0000;\">BPF \u7a0b\u5e8f\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff08fd\uff09<\/span>\u3002<\/li>\n<\/ul>\n<p id=\"\u4f7f\u7528\u573a\u666f\u5c3e\u8c03\u7528tail-call\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li>\u5c3e\u8c03\u7528\uff08tail call\uff09<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-5\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li id=\"1-\u6839\u636e\u534f\u8bae\u7c7b\u578b\u5c3e\u8c03\u7528\u5230\u4e0b\u4e00\u5c42-parsersamplesbpfsockex3\">\u6839\u636e\u534f\u8bae\u7c7b\u578b\u5c3e\u8c03\u7528\u5230\u4e0b\u4e00\u5c42 parser\uff1asamples\/bpf\/sockex3<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">3.4 BPF_MAP_TYPE_PERF_EVENT_ARRAY<\/h6>\n<p id=\"\u4f7f\u7528\u573a\u666f\u4fdd\u5b58-tracing-\u7ed3\u679c\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li>\u4fdd\u5b58 tracing \u7ed3\u679c<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-6\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li id=\"1-\u4fdd\u5b58-perf-eventsamplesbpftrace_output_kernc\">\u4fdd\u5b58 perf event\uff1asamples\/bpf\/trace_output_kern.c<\/li>\n<\/ul>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"c1\">\/\/ samples\/bpf\/trace_output_kern.c<\/span>\r\n\r\n<span class=\"k\">struct<\/span> <span class=\"n\">bpf_map_def<\/span> <span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"maps\"<\/span><span class=\"p\">)<\/span> <span class=\"n\">my_map<\/span> <span class=\"o\">=<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">type<\/span> <span class=\"o\">=<\/span> <span class=\"n\">BPF_MAP_TYPE_PERF_EVENT_ARRAY<\/span><span class=\"p\">,\r\n    .<span class=\"n\">max_entries<\/span> <span class=\"o\">=<\/span> <span class=\"mi\">2<\/span>,<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">key_size<\/span> <span class=\"o\">=<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"kt\">int<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">value_size<\/span> <span class=\"o\">=<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"n\">u32<\/span><span class=\"p\">),<\/span>\r\n<span class=\"p\">};<\/span>\r\n\r\n<span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"kprobe\/sys_write\"<\/span><span class=\"p\">)<\/span>\r\n<span class=\"kt\">int<\/span> <span class=\"nf\">bpf_prog1<\/span><span class=\"p\">(<\/span><span class=\"k\">struct<\/span> <span class=\"n\">pt_regs<\/span> <span class=\"o\">*<\/span><span class=\"n\">ctx<\/span><span class=\"p\">)<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"k\">struct<\/span> <span class=\"n\">S<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">u64<\/span> <span class=\"n\">pid<\/span><span class=\"p\">;<\/span>\r\n        <span class=\"n\">u64<\/span> <span class=\"n\">cookie<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"p\">}<\/span> <span class=\"n\">data<\/span><span class=\"p\">;<\/span>\r\n\r\n    <span class=\"n\">data<\/span><span class=\"p\">.<\/span><span class=\"n\">pid<\/span> <span class=\"o\">=<\/span> <span class=\"n\">bpf_get_current_pid_tgid<\/span><span class=\"p\">();<\/span>\r\n    <span class=\"n\">data<\/span><span class=\"p\">.<\/span><span class=\"n\">cookie<\/span> <span class=\"o\">=<\/span> <span class=\"mh\">0x12345678<\/span><span class=\"p\">;<\/span>\r\n\r\n    <span class=\"n\">bpf_perf_event_output<\/span><span class=\"p\">(<\/span><span class=\"n\">ctx<\/span><span class=\"p\">,<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">my_map<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">,<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">data<\/span><span class=\"p\">,<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"n\">data<\/span><span class=\"p\">));<\/span>\r\n\r\n    <span class=\"k\">return<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<\/div>\n<h6 id=\"1-bpf_map_type_hash\">3.5 BPF_MAP_TYPE_ARRAY_OF_MAPS<\/h6>\n<p id=\"\u4f7f\u7528\u573a\u666fmap-in-map\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li>map-in-map\n<ul>\n<li>map-in-map\uff0cvalues \u662f\u6307\u5411\u5185\u5c42 map \u7684 fd\u3002\u53ea\u652f\u6301\u4e24\u5c42 map\u3002 two levels of map\uff0c\u4e5f\u5c31\u662f\u4e00\u5c42 map \u5d4c\u5957\u53e6\u4e00\u5c42 map\u3002<\/li>\n<li><span style=\"color: #ff0000;\">BPF_MAP_TYPE_PROG_ARRAY<\/span>\u7c7b\u578b\u7684 BPF \u7a0b\u5e8f<span style=\"color: #ff0000;\">\u4e0d\u652f\u6301 map-in-map \u529f\u80fd\u00a0<\/span>\uff0c\u56e0\u4e3a\u8fd9\u4f1a\u4f7f tail call \u7684 verification \u66f4\u52a0\u56f0\u96be\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-7\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li>samples\/bpf\/map_perf_test_kern.c<\/li>\n<li>samples\/bpf\/test_map_in_map_kern.c<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">3.6\u00a0BPF_MAP_TYPE_CGROUP_ARRAY<\/h6>\n<p>\u5728\u7528\u6237\u7a7a\u95f4\u5b58\u653e cgroup fds\uff0c<span style=\"color: #ff0000;\">\u7528\u6765\u68c0\u67e5\u7ed9\u5b9a\u7684 skb \u662f\u5426\u4e0e cgroup_array[index] \u6307\u5411\u7684 cgroup \u5173\u8054<\/span>\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-4\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00cgroup-\u7ea7\u522b\u7684\u5305\u8fc7\u6ee4\u62d2\u7edd\u653e\u884c\">cgroup \u7ea7\u522b\u7684\u5305\u8fc7\u6ee4\uff08\u62d2\u7edd\/\u653e\u884c\uff09<\/li>\n<li id=\"\u573a\u666f\u4e8ccgroup-\u7ea7\u522b\u7684\u8fdb\u7a0b\u8fc7\u6ee4\u6743\u9650\u63a7\u5236\u7b49\">cgroup \u7ea7\u522b\u7684\u8fdb\u7a0b\u8fc7\u6ee4\uff08\u6743\u9650\u63a7\u5236\u7b49\uff09<\/li>\n<\/ul>\n<p id=\"\u7a0b\u5e8f\u793a\u4f8b-8\">\u7a0b\u5e8f\u793a\u4f8b\uff1a<\/p>\n<ul>\n<li id=\"1-pin--update-pinned-cgroup-arraysamplesbpftest_cgrp2_array_pinc\">Pin &amp; update pinned cgroup array\uff1asamples\/bpf\/test_cgrp2_array_pin.c\n<ul>\n<li>\u5c06 cgroupv2 array pin \u5230 BPFFS<\/li>\n<li>\u66f4\u65b0 pinned cgroupv2 array<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"c1\">\/\/ samples\/bpf\/test_cgrp2_array_pin.c<\/span>\r\n\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"n\">create_array<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">array_fd<\/span> <span class=\"o\">=<\/span> <span class=\"n\">bpf_create_map<\/span><span class=\"p\">(<\/span><span class=\"n\">BPF_MAP_TYPE_CGROUP_ARRAY<\/span><span class=\"p\">,<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"kt\">uint32_t<\/span><span class=\"p\">),<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"kt\">uint32_t<\/span><span class=\"p\">),<\/span> <span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"p\">}<\/span> <span class=\"k\">else<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">array_fd<\/span> <span class=\"o\">=<\/span> <span class=\"n\">bpf_obj_get<\/span><span class=\"p\">(<\/span><span class=\"n\">pinned_file<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"p\">}<\/span>\r\n\r\n    <span class=\"n\">bpf_map_update_elem<\/span><span class=\"p\">(<\/span><span class=\"n\">array_fd<\/span><span class=\"p\">,<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">array_key<\/span><span class=\"p\">,<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">cg2_fd<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span>\r\n\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"n\">create_array<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">ret<\/span> <span class=\"o\">=<\/span> <span class=\"n\">bpf_obj_pin<\/span><span class=\"p\">(<\/span><span class=\"n\">array_fd<\/span><span class=\"p\">,<\/span> <span class=\"n\">pinned_file<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<\/div>\n<ul>\n<li id=\"2-cgroup-\u7ea7\u522b\u7684\u5305\u8fc7\u6ee4samplesbpftest_cgrp2_tc_kernc\">CGroup \u7ea7\u522b\u7684\u5305\u8fc7\u6ee4\uff1asamples\/bpf\/test_cgrp2_tc_kern.c\n<ul>\n<li>\u6838\u5fc3\u662f\u8c03\u7528\u00a0bpf_skb_under_cgroup()\u00a0\u5224\u65ad skb \u662f\u5426\u5728\u7ed9\u5b9a cgroup \u4e2d\uff1a<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"c1\">\/\/ samples\/bpf\/test_cgrp2_tc_kern.c<\/span>\r\n\r\n<span class=\"k\">struct<\/span> <span class=\"n\">bpf_elf_map<\/span> <span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"maps\"<\/span><span class=\"p\">)<\/span> <span class=\"n\">test_cgrp2_array_pin<\/span> <span class=\"o\">=<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">type<\/span>        <span class=\"o\">=<\/span> <span class=\"n\">BPF_MAP_TYPE_CGROUP_ARRAY<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">size_key<\/span>    <span class=\"o\">=<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"kt\">uint32_t<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">size_value<\/span>  <span class=\"o\">=<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"kt\">uint32_t<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">pinning<\/span>     <span class=\"o\">=<\/span> <span class=\"n\">PIN_GLOBAL_NS<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">max_elem<\/span>    <span class=\"o\">=<\/span> <span class=\"mi\">1<\/span><span class=\"p\">,<\/span>\r\n<span class=\"p\">};<\/span>\r\n\r\n<span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"filter\"<\/span><span class=\"p\">)<\/span>\r\n<span class=\"kt\">int<\/span> <span class=\"nf\">handle_egress<\/span><span class=\"p\">(<\/span><span class=\"k\">struct<\/span> <span class=\"n\">__sk_buff<\/span> <span class=\"o\">*<\/span><span class=\"n\">skb<\/span><span class=\"p\">)<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"p\">...<\/span>\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"n\">bpf_skb_under_cgroup<\/span><span class=\"p\">(<\/span><span class=\"n\">skb<\/span><span class=\"p\">,<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">test_cgrp2_array_pin<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"o\">!=<\/span> <span class=\"mi\">1<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">bpf_trace_printk<\/span><span class=\"p\">(<\/span><span class=\"n\">pass_msg<\/span><span class=\"p\">,<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"n\">pass_msg<\/span><span class=\"p\">));<\/span>\r\n        <span class=\"k\">return<\/span> <span class=\"n\">TC_ACT_OK<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"p\">}<\/span>\r\n    <span class=\"p\">...<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<\/div>\n<ul>\n<li id=\"3-\u5224\u65ad\u8fdb\u7a0b\u662f\u5426\u5728\u7ed9\u5b9a-cgroup-\u4e2dsamplesbpftest_current_task_under_cgroup_kernc\">\u5224\u65ad\u8fdb\u7a0b\u662f\u5426\u5728\u7ed9\u5b9a cgroup \u4e2d\uff1asamples\/bpf\/test_current_task_under_cgroup_kern.c\n<ul>\n<li>\u8c03\u7528\u00a0bpf_current_task_under_cgroup()\u00a0<span style=\"color: #ff0000;\">\u5224\u65ad\u5f53\u524d\u8fdb\u7a0b\u662f\u5426\u5728\u7ed9\u5b9a cgroup \u4e2d<\/span>\uff1a<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code>\r\n<span class=\"k\">struct<\/span> <span class=\"n\">bpf_map_def<\/span> <span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"maps\"<\/span><span class=\"p\">)<\/span> <span class=\"n\">cgroup_map<\/span> <span class=\"o\">=<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">type<\/span>            <span class=\"o\">=<\/span> <span class=\"n\">BPF_MAP_TYPE_CGROUP_ARRAY<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">key_size<\/span>        <span class=\"o\">=<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"n\">u32<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">value_size<\/span>        <span class=\"o\">=<\/span> <span class=\"k\">sizeof<\/span><span class=\"p\">(<\/span><span class=\"n\">u32<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"p\">.<\/span><span class=\"n\">max_entries<\/span>    <span class=\"o\">=<\/span> <span class=\"mi\">1<\/span><span class=\"p\">,<\/span>\r\n<span class=\"p\">};<\/span>\r\n\r\n<span class=\"cm\">\/* Writes the last PID that called sync to a map at index 0 *\/<\/span>\r\n<span class=\"n\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\"kprobe\/sys_sync\"<\/span><span class=\"p\">)<\/span>\r\n<span class=\"kt\">int<\/span> <span class=\"nf\">bpf_prog1<\/span><span class=\"p\">(<\/span><span class=\"k\">struct<\/span> <span class=\"n\">pt_regs<\/span> <span class=\"o\">*<\/span><span class=\"n\">ctx<\/span><span class=\"p\">)<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"p\">...<\/span>\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"o\">!<\/span><span class=\"n\">bpf_current_task_under_cgroup<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">cgroup_map<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">))<\/span>\r\n        <span class=\"k\">return<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"p\">...<\/span>\r\n<span class=\"p\">}<\/span><\/code><\/pre>\n<\/div>\n<p>&nbsp;<\/p>\n<h4>4. CGroup Maps<\/h4>\n<h6 id=\"1-bpf_map_type_hash\">4.1 BPF_MAP_TYPE_CGROUP_ARRAY<\/h6>\n<p>\u4e0a\u8fb93.6\u8282\u5df2\u7ecf\u6709\u8be6\u7ec6\u4ecb\u7ecd\u3002<\/p>\n<h6 id=\"1-bpf_map_type_hash\">4.2 BPF_MAP_TYPE_CGROUP_STORAGE<\/h6>\n<p>Attach \u5230\u4e00\u4e2a cgroup \u7684\u6240\u6709 BPF \u7a0b\u5e8f\uff0c\u4f1a\u5171\u7528\u4e00\u7ec4 cgroup storage\uff0c\u5305\u62ec\uff1a<\/p>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code>    <span class=\"k\">for<\/span> <span class=\"p\">(<\/span><span class=\"n\">stype<\/span> <span class=\"o\">=<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span> <span class=\"n\">stype<\/span> <span class=\"o\">&lt;<\/span> <span class=\"n\">MAX_BPF_CGROUP_STORAGE_TYPE<\/span><span class=\"p\">;<\/span> <span class=\"n\">stype<\/span><span class=\"o\">++<\/span><span class=\"p\">)<\/span>\r\n        <span class=\"n\">storages<\/span><span class=\"p\">[<\/span><span class=\"n\">stype<\/span><span class=\"p\">]<\/span> <span class=\"o\">=<\/span> <span class=\"n\">bpf_cgroup_storage_alloc<\/span><span class=\"p\">(<\/span><span class=\"n\">prog<\/span><span class=\"p\">,<\/span> <span class=\"n\">stype<\/span><span class=\"p\">);<\/span>\r\n<\/code><\/pre>\n<\/div>\n<p>\u8fd9\u91cc\u7684 types \u76ee\u524d\u53ea\u6709\u4e24\u79cd\uff1ashared\u3001per-cpu<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-5\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00cgroup-\u5185\u6240\u6709-bpf-\u7a0b\u5e8f\u7684\u5171\u4eab\u5b58\u50a8\">cgroup \u5185\u6240\u6709 BPF \u7a0b\u5e8f\u7684\u5171\u4eab\u5b58\u50a8\uff1asamples\/bpf\/hbm_kern.h\uff1ahost bandwidth manager<\/li>\n<\/ul>\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"k\">struct<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">__uint<\/span><span class=\"p\">(<\/span><span class=\"n\">type<\/span><span class=\"p\">,<\/span> <span class=\"n\">BPF_MAP_TYPE_CGROUP_STORAGE<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"n\">__type<\/span><span class=\"p\">(<\/span><span class=\"n\">key<\/span><span class=\"p\">,<\/span> <span class=\"k\">struct<\/span> <span class=\"n\">bpf_cgroup_storage_key<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"n\">__type<\/span><span class=\"p\">(<\/span><span class=\"n\">value<\/span><span class=\"p\">,<\/span> <span class=\"k\">struct<\/span> <span class=\"n\">hbm_vqueue<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span> <span class=\"n\">queue_state<\/span> <span class=\"nf\">SEC<\/span><span class=\"p\">(<\/span><span class=\"s\">\".maps\"<\/span><span class=\"p\">);<\/span>\r\n<\/code><\/pre>\n<\/div>\n<h6 id=\"1-bpf_map_type_hash\">4.3 BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE<\/h6>\n<p>\u540c\u4e0a\u3002<\/p>\n<p>&nbsp;<\/p>\n<h4>5. Tracing Maps<\/h4>\n<h6 id=\"1-bpf_map_type_hash\">5.1 BPF_MAP_TYPE_STACK_TRACE<\/h6>\n<p>\u5185\u6838\u7a0b\u5e8f\u80fd\u901a\u8fc7 bpf_get_stackid() helper \u5b58\u50a8 stack \u4fe1\u606f\u3002 \u5c06 stack \u4fe1\u606f\u5173\u8054\u5230\u4e00\u4e2a id\uff0c\u800c\u8fd9\u4e2a id \u662f<span style=\"color: #ff0000;\">\u5bf9\u5f53\u524d\u6808\u7684 \u6307\u4ee4\u6307\u9488\u5730\u5740\uff08instruction pointer address\uff09\u8fdb\u884c 32-bit hash<\/span>\u00a0\u5f97\u5230\u7684\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-6\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00\u5b58\u50a8-profiling-\u4fe1\u606f\">\u5b58\u50a8 profiling \u4fe1\u606f\n<ul>\n<li>\u5728\u5185\u6838\u4e2d\u83b7\u53d6 stack id\uff0c\u7528\u5b83\u4f5c\u4e3a key \u66f4\u65b0\u53e6\u4e00\u4e2a map\u3002 \u4f8b\u5982\u901a\u8fc7\u5bf9\u6307\u5b9a\u7684 stack traces \u8fdb\u884c profiling\uff0c\u7edf\u8ba1\u5b83\u4eec\u7684\u51fa\u73b0\u6b21\u6570\uff0c\u6216\u8005\u5c06 stack trace \u4fe1\u606f\u4e0e\u5f53\u524d pid \u5173\u8054\u8d77\u6765\u3002<\/li>\n<li id=\"\u7a0b\u5e8f\u793a\u4f8b-10\">\u7a0b\u5e8f\u793a\u4f8b\uff1a\u6253\u5370\u8c03\u7528\u6808\uff1asamples\/bpf\/offwaketime_kern.c<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">5.2 BPF_MAP_TYPE_STACK<\/h6>\n<h6 id=\"1-bpf_map_type_hash\">5.3 BPF_MAP_TYPE_RINGBUF<\/h6>\n<p>BPF perf buffer\uff08perfbuf\uff09\u662f\u76ee\u524d\u8fd9\u4e00\u8fc7\u7a0b\u7684\u4e8b\u5b9e\u6807\u51c6\uff0c\u4f46\u5b83\u5b58\u5728\u4e00\u4e9b\u95ee\u9898\uff0c\u4f8b\u5982 \u6d6a\u8d39\u5185\u5b58\uff08\u56e0\u4e3a\u5176 per-CPU \u8bbe\u8ba1\uff09\u3001\u4e8b\u4ef6\u987a\u5e8f\u65e0\u6cd5\u4fdd\u8bc1\u7b49\u3002<\/p>\n<p>\u4f5c\u4e3a\u6539\u8fdb\uff0c\u5185\u6838 5.8 \u5f15\u5165\u53e6\u4e00\u4e2a\u65b0\u7684 BPF \u6570\u636e\u7ed3\u6784\uff1aBPF ring buffer\uff08\u73af\u5f62\u7f13\u51b2\u533a\uff0cringbuf\uff09\uff1a<\/p>\n<ul>\n<li>\u76f8\u6bd4 perf buffer\uff0c\u5b83<span style=\"color: #ff0000;\">\u5185\u5b58\u6548\u7387\u66f4\u9ad8\u3001\u4fdd\u8bc1\u4e8b\u4ef6\u987a\u5e8f<\/span>\uff0c\u6027\u80fd\u4e5f\u4e0d\u8f93\u524d\u8005\uff1b<\/li>\n<li>\u5728\u4f7f\u7528\u4e0a\uff0c\u65e2\u63d0\u4f9b\u4e86\u4e0e perf buffer \u7c7b\u4f3c\u7684 API \uff0c\u4ee5\u65b9\u4fbf\u7528\u6237\u8fc1\u79fb\uff1b\u53c8\u63d0\u4f9b\u4e86\u4e00\u5957\u65b0\u7684\u00a0<span style=\"color: #ff0000;\">reserve\/commit API\uff08\u5148\u9884\u7559\u518d\u63d0\u4ea4\uff09\uff0c\u4ee5\u5b9e\u73b0\u66f4\u9ad8\u6027\u80fd<\/span>\u3002<\/li>\n<\/ul>\n<p>ringbuf \u662f\u4e00\u4e2a\u201c<span style=\"color: #ff0000;\">\u591a\u751f\u4ea7\u8005\u3001\u5355\u6d88\u8d39\u8005<\/span>\u201d\uff08multi-producer, single-consumer\uff0cMPSC\uff09 \u961f\u5217\uff0c<span style=\"color: #ff0000;\">\u53ef\u5b89\u5168\u5730\u5728\u591a\u4e2a CPU \u4e4b\u95f4\u5171\u4eab\u548c\u64cd\u4f5c<\/span>\u3002perfbuf \u652f\u6301\u7684\u4e00\u4e9b\u529f\u80fd\u5b83\u90fd\u652f\u6301\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>\u53ef\u53d8\u957f\u6570\u636e\uff08variable-length data records\uff09\uff1b<\/li>\n<li>\u901a\u8fc7 memory-mapped region \u6765\u9ad8\u6548\u5730\u4ece userspace \u8bfb\u6570\u636e\uff0c\u907f\u514d\u5185\u5b58\u590d\u5236\u6216\u7cfb\u7edf\u8c03\u7528\uff1b<\/li>\n<li>\u652f\u6301 epoll notifications \u548c busy-loop \u4e24\u79cd\u83b7\u53d6\u6570\u636e\u65b9\u5f0f\u3002<\/li>\n<\/ul>\n<p>\u6b64\u5916\uff0c\u5b9e\u9a8c\u4e0e\u771f\u5b9e\u73af\u5883\u7684\u538b\u6d4b\u7ed3\u679c\u90fd\u8868\u660e\uff0c\u4ece BPF \u7a0b\u5e8f\u53d1\u9001\u6570\u636e\u7ed9\u7528\u6237\u7a7a\u95f4\u65f6\uff0c\u00a0<span style=\"color: #ff0000;\">\u5e94\u8be5\u9996\u9009 BPF ring buffer<\/span>\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-8\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00\u66f4\u9ad8\u6548\u4fdd\u8bc1\u4e8b\u4ef6\u987a\u5e8f\u5730\u5f80\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6570\u636e\">\u66f4\u9ad8\u6548\u3001\u4fdd\u8bc1\u4e8b\u4ef6\u987a\u5e8f\u5730\u5f80\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6570\u636e\n<ul>\n<li>\u8be6\u89c1\u00a0<a href=\"http:\/\/arthurchiao.art\/blog\/bpf-ringbuf-zh\/\">(\u8bd1) BPF ring buffer\uff1a\u4f7f\u7528\u573a\u666f\u3001\u6838\u5fc3\u8bbe\u8ba1\u53ca\u7a0b\u5e8f\u793a\u4f8b\uff082020\uff09<\/a>\u3002<\/li>\n<\/ul>\n<\/li>\n<li id=\"\u7a0b\u5e8f\u793a\u4f8b-11\">\u5e38\u89c4\u573a\u666f\uff1a\u5bf9\u4e8e\u6240\u6709\u5b9e\u9645\u573a\u666f\uff08\u5c24\u5176\u662f\u90a3\u4e9b\u57fa\u4e8e bcc\/libbpf \u7684\u9ed8\u8ba4\u914d\u7f6e\u5728\u4f7f\u7528 perfbuf \u7684\u573a\u666f\uff09\uff0c ringbuf \u7684\u6027\u80fd\u90fd\u4f18\u4e8e perfbuf \u6027\u80fd\u3002\u5404\u79cd\u4e0d\u540c\u573a\u666f\u7684\u4eff\u771f\u538b\u6d4b\uff08synthetic benchmarking\uff09<\/li>\n<li>\u9ad8\u541e\u5410\u573a\u666f\uff1a\u6bcf\u79d2\u767e\u4e07\u7ea7\u4e8b\u4ef6\uff08millions of events per second\uff09\u4ee5\u4e0a\u7684\u573a\u666f<\/li>\n<\/ul>\n<p>\u5185\u6838 BPF \u793a\u4f8b\u7a0b\u5e8f\uff1a<a href=\"https:\/\/github.com\/anakryiko\/bpf-ringbuf-examples\/blob\/main\/src\/ringbuf-output.bpf.c\">BPF-side code<\/a><\/p>\n<pre class=\"pure-highlightjs\"><code class=\"\">--- src\/perfbuf-output.bpf.c\t2020-10-25 18:52:22.247019800 -0700\r\n+++ src\/ringbuf-output.bpf.c\t2020-10-25 18:44:14.510630322 -0700\r\n@@ -6,12 +6,11 @@\r\n \r\n char LICENSE[] SEC(\"license\") = \"Dual BSD\/GPL\";\r\n \r\n-\/* BPF perfbuf map *\/\r\n+\/* BPF ringbuf map *\/\r\n struct {\r\n-\t__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);\r\n-\t__uint(key_size, sizeof(int));\r\n-\t__uint(value_size, sizeof(int));\r\n-} pb SEC(\".maps\");\r\n+\t__uint(type, BPF_MAP_TYPE_RINGBUF);\r\n+\t__uint(max_entries, 256 * 1024); \/\/ 256 KB\r\n+} rb SEC(\".maps\");\r\n \r\n struct {\r\n \t__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);\r\n@@ -35,7 +34,7 @@\r\n \tbpf_get_current_comm(&amp;e-&gt;comm, sizeof(e-&gt;comm));\r\n \tbpf_probe_read_str(&amp;e-&gt;filename, sizeof(e-&gt;filename), (void *)ctx + fname_off);\r\n \r\n-\tbpf_perf_event_output(ctx, &amp;pb, BPF_F_CURRENT_CPU, e, sizeof(*e));\r\n+\tbpf_ringbuf_output(&amp;rb, e, sizeof(*e), 0);\r\n \treturn 0;\r\n }<\/code><\/pre>\n<p>\u53ef\u4ee5\u770b\u5230\u4e24\u8005\u7684\u5dee\u5f02\uff1a<\/p>\n<ul>\n<li>max_entries \u7684\u5355\u4f4d\u662f\u5b57\u8282\uff0c\u5fc5\u987b\u662f\u5185\u6838\u9875\u5927\u5c0f\uff08 \u51e0\u4e4e\u6c38\u8fdc\u662f 4096\uff09\u7684\u500d\u6570\uff0c\u4e5f\u5fc5\u987b\u662f 2 \u7684\u5e42\u6b21\u3002<\/li>\n<li>bpf_perf_event_output()\u00a0\u66ff\u6362\u6210\u4e86\u7c7b\u4f3c\u7684\u00a0bpf_ringbuf_output()\uff0c\u540e\u8005\u66f4\u7b80\u5355\uff0c\u4e0d\u9700\u8981 BPF context \u53c2\u6570<\/li>\n<\/ul>\n<p>\u7528\u6237\u7a7a\u95f4\u793a\u4f8b\u7a0b\u5e8f\uff1a<a href=\"https:\/\/github.com\/anakryiko\/bpf-ringbuf-examples\/blob\/main\/src\/ringbuf-output.c\">user-space code<\/a><\/p>\n<p>\u4e8b\u4ef6 handler \u7b7e\u540d\u6709\u70b9\u53d8\u5316\uff1a<\/p>\n<ol>\n<li>\u4f1a\u8fd4\u56de\u9519\u8bef\u4fe1\u606f\uff08\u8fdb\u800c\u7ec8\u6b62 consumer \u5faa\u73af\uff09<\/li>\n<li>\u53c2\u6570\u91cc\u9762\u53bb\u6389\u4e86\u4ea7\u751f\u8fd9\u4e2a\u4e8b\u4ef6\u7684 CPU Index<\/li>\n<\/ol>\n<div class=\"language-diff highlighter-rouge\">\n<div class=\"highlight\">\n<pre class=\"highlight\"><code><span class=\"gd\">-void handle_event(void *ctx, int cpu, void *data, unsigned int data_sz)\r\n<\/span><span class=\"gi\">+int handle_event(void *ctx, void *data, size_t data_sz)\r\n<\/span><span class=\"err\">{<\/span>\r\n\tconst struct event *e = data;\r\n\tstruct tm *tm;<\/code><\/pre>\n<\/div>\n<\/div>\n<h6><\/h6>\n<h6 id=\"1-bpf_map_type_hash\">5.4 BPF_MAP_TYPE_PERF_EVENT_ARRAY<\/h6>\n<p id=\"\u4f7f\u7528\u573a\u666f-9\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00perf-events\">Perf events\uff1aBPF \u7a0b\u5e8f\u5c06\u6570\u636e\u5b58\u50a8\u5728\u00a0<code class=\"language-plaintext highlighter-rouge\">mmap()<\/code>\u00a0\u5171\u4eab\u5185\u5b58\u4e2d\uff0c\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f\u53ef\u4ee5\u8bbf\u95ee\u3002samples\/bpf\/trace_output\uff1atrace\u00a0write()\u00a0\u7cfb\u7edf\u8c03\u7528\n<ul>\n<li>\u975e\u56fa\u5b9a\u5927\u5c0f\u6570\u636e\uff08\u4e0d\u9002\u5408 map\uff09<\/li>\n<li>\u65e0\u9700\u4e0e\u5176\u4ed6 BPF \u7a0b\u5e8f\u5171\u4eab\u6570\u636e<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h4>6. Socket Maps<\/h4>\n<h6 id=\"1-bpf_map_type_hash\">6.1 BPF_MAP_TYPE_SOCKMAP<\/h6>\n<p>\u4e3b\u8981\u7528\u4e8e socket redirection\uff1a\u5c06 sockets \u4fe1\u606f\u63d2\u5165\u5230 map\uff0c\u540e\u9762\u6267\u884c\u5230 bpf_sockmap_redirect() \u65f6\uff0c\u7528 map \u91cc\u7684\u4fe1\u606f\u89e6\u53d1\u91cd\u5b9a\u5411\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-10\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00socket-redirection\u91cd\u5b9a\u5411\">socket redirection\uff08\u91cd\u5b9a\u5411\uff09<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">6.2 BPF_MAP_TYPE_REUSEPORT_SOCKARRAY<\/h6>\n<p>\u914d\u5408\u00a0BPF_PROG_TYPE_SK_REUSEPORT\u00a0\u7c7b\u578b\u7684 BPF \u7a0b\u5e8f\u4f7f\u7528\uff0c\u52a0\u901f socket \u67e5\u627e\u3002<\/p>\n<p id=\"\u4f7f\u7528\u573a\u666f-11\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00\u914d\u5408-_sk_reuseport-\u7c7b\u578b-bpf-\u7a0b\u5e8f\u52a0\u901f-socket-\u67e5\u627e\">\u914d\u5408 _SK_REUSEPORT\u00a0\u7c7b\u578b BPF \u7a0b\u5e8f\uff0c\u52a0\u901f socket \u67e5\u627e<\/li>\n<\/ul>\n<h6 id=\"1-bpf_map_type_hash\">6.3 BPF_MAP_TYPE_SK_STORAGE<\/h6>\n<p id=\"\u4f7f\u7528\u573a\u666f-12\">\u4f7f\u7528\u573a\u666f\uff1a<\/p>\n<ul>\n<li id=\"\u573a\u666f\u4e00per-socket-\u5b58\u50a8\u7a7a\u95f4\">per-socket \u5b58\u50a8\u7a7a\u95f4<\/li>\n<li>\u5728\u5185\u6838\u5b9a\u671f dump socket \u8be6\u60c5\uff1asamples\/bpf\/tcp_dumpstats_kern.c<\/li>\n<\/ul>\n<pre class=\"pure-highlightjs\"><code class=\"\">struct {\r\n    __u32 type;\r\n    __u32 map_flags;\r\n    int *key;\r\n    __u64 *value;\r\n} bpf_next_dump SEC(\".maps\") = {\r\n    .type = BPF_MAP_TYPE_SK_STORAGE,\r\n    .map_flags = BPF_F_NO_PREALLOC,\r\n};\r\n\r\nSEC(\"sockops\")\r\nint _sockops(struct bpf_sock_ops *ctx)\r\n{\r\n    struct bpf_tcp_sock *tcp_sk;\r\n    struct bpf_sock *sk;\r\n    __u64 *next_dump;\r\n\r\n    switch (ctx-&gt;op) {\r\n    case BPF_SOCK_OPS_TCP_CONNECT_CB:\r\n        bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);\r\n        return 1;\r\n    case BPF_SOCK_OPS_RTT_CB:\r\n        break;\r\n    default:\r\n        return 1;\r\n    }\r\n\r\n    sk = ctx-&gt;sk;\r\n    next_dump = bpf_sk_storage_get(&amp;bpf_next_dump, sk, 0, BPF_SK_STORAGE_GET_F_CREATE);\r\n    now = bpf_ktime_get_ns();\r\n    if (now &lt; *next_dump)\r\n        return 1;\r\n\r\n    tcp_sk = bpf_tcp_sock(sk);\r\n    *next_dump = now + INTERVAL;\r\n\r\n    bpf_printk(\"dsack_dups=%u delivered=%u\\n\", tcp_sk-&gt;dsack_dups, tcp_sk-&gt;delivered);\r\n    bpf_printk(\"delivered_ce=%u icsk_retransmits=%u\\n\", tcp_sk-&gt;delivered_ce, tcp_sk-&gt;icsk_retransmits);\r\n\r\n    return 1;\r\n}<\/code><\/pre>\n<p>\u603b\u4f53\u6765\u770b\uff0cBPF_MAP_TYPE_HASH\u3001BPF_MAP_TYPE_ARRAY\u3001<span style=\"font-size: 1rem;\">BPF_MAP_TYPE_RINGBUF\u8fd9\u4e2a\u7c7b\u578b\u57fa\u672c\u53ef\u4ee5\u8986\u76d6\u5230\u5927\u90e8\u5206\u5185\u6838\u4e0e\u7528\u6237\u7a7a\u95f4\u4f20\u9012\u6570\u636e\u7684\u9700\u6c42\u573a\u666f\uff0c\u4e14\u80fd\u6ee1\u8db3\u9ad8\u6027\u80fd\u7684\u8981\u6c42\u3002<\/span><\/p>\n<h1><\/h1>\n<h1>\u4e09\u3001BPF Map\u64cd\u4f5c<\/h1>\n<p>BPF Map\u521b\u5efa\u540e\uff0c\u5bf9\u5176CRUD\u64cd\u4f5c\u4e3b\u8981\u6d89\u53ca\u51e0\u4e2a\u65b9\u6cd5\uff1a<\/p>\n<pre class=\"language-c\" tabindex=\"0\"><code class=\"language-c\">helper<span class=\"token operator\">:<\/span><span class=\"token punctuation\">(<\/span>kernel space<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span><span class=\"token function\">bpf_map_lookup_elem<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">bpf_map<\/span> <span class=\"token operator\">*<\/span>map<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>key<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token keyword\">long<\/span> <span class=\"token function\">bpf_map_update_elem<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">bpf_map<\/span> <span class=\"token operator\">*<\/span>map<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>key<span class=\"token punctuation\">,<\/span>\r\n       <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>value<span class=\"token punctuation\">,<\/span> u64 flags<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token keyword\">long<\/span> <span class=\"token function\">bpf_map_delete_elem<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">bpf_map<\/span> <span class=\"token operator\">*<\/span>map<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>key<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span>\r\n\r\nlibbpf<span class=\"token operator\">:<\/span><span class=\"token punctuation\">(<\/span>user space<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token comment\">\/\/ https:\/\/elixir.bootlin.com\/linux\/v4.19.261\/source\/tools\/lib\/bpf\/bpf.c#L299<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">bpf_map_lookup_elem<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>key<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>value<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">bpf_map_update_elem<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>key<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>value<span class=\"token punctuation\">,<\/span>\r\n\t\t\t__u64 flags<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">bpf_map_delete_elem<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>key<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token operator\">-<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><\/code><\/pre>\n<h4>1. bpf_map_lookup_elem(map, key)<\/h4>\n<p>\u901a\u8fc7key\u67e5\u8be2BPF Map\uff0c\u5f97\u5230\u5bf9\u5e94value\u3002<\/p>\n<h4>2. bpf_map_update_elem(map, key, value, options)<\/h4>\n<p>\u901a\u8fc7key-value\u66f4\u65b0BPF Map\uff0c\u5982\u679c\u8fd9\u4e2akey\u4e0d\u5b58\u5728\uff0c\u4e5f\u53ef\u4ee5\u4f5c\u4e3a\u65b0\u7684\u5143\u7d20\u63d2\u5165\u5230BPF Map\u4e2d\u53bb\u3002<\/p>\n<h4>3. bpf_map_delete_elem(map, key)<\/h4>\n<p>\u5220\u9664BPF Map\u4e2d\u7684\u67d0\u4e2akey\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>\u597d\u4e86\uff0c\u4eca\u5929\u4e3b\u8981\u719f\u6089\u4e86\u4e0bBPF Map\u7684\u4f5c\u7528\u3001\u5e38\u89c1Map\u7c7b\u578b\u7684\u4f7f\u7528\u65b9\u6cd5\u3001\u4ee5\u53caMap\u7684\u5e38\u89c4\u64cd\u4f5c\u3002\u4e0b\u4e00\u6b21\uff0c\u6211\u4eec\u518d\u7ee7\u7eed\u6df1\u5165\u7684\u5b66\u4e60eBPF\u7a0b\u5e8f\u7684\u5f00\u53d1\u65b9\u6cd5\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>yan 23.12.8<\/p>\n<p>&nbsp;<\/p>\n<p>\u53c2\u8003\uff1a<\/p>\n<p><a href=\"https:\/\/www.edony.ink\/deepinsight-of-ebpf-map\/\" target=\"_blank\" rel=\"noopener\">\u6df1\u5165\u4e86\u89e3 ebpf map<\/a><\/p>\n<p><a href=\"http:\/\/arthurchiao.art\/blog\/bpf-advanced-notes-2-zh\/\" target=\"_blank\" rel=\"noopener\">BPF \u8fdb\u9636\u7b14\u8bb0\uff08\u4e8c\uff09\uff1aBPF Map \u7c7b\u578b\u8be6\u89e3\uff1a\u4f7f\u7528\u573a\u666f\u3001\u7a0b\u5e8f\u793a\u4f8b<\/a><\/p>\n<p><a href=\"http:\/\/arthurchiao.art\/blog\/bpf-ringbuf-zh\/\" target=\"_blank\" rel=\"noopener\">[\u8bd1] BPF ring buffer\uff1a\u4f7f\u7528\u573a\u666f\u3001\u6838\u5fc3\u8bbe\u8ba1\u53ca\u7a0b\u5e8f\u793a\u4f8b\uff082020\uff09<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e0a\u4e00\u6b21\uff0c\u6211\u4eec\u5bf9eBPF\u6709\u4e86\u57fa\u672c\u7684\u4e86\u89e3\uff0c\u5e76\u5b9e\u73b0\u4e86\u4e00\u4e2a\u7b80\u5355\u7684kprobe\u76d1\u542c\u3002\u672c\u6587\u6211\u4eec\u4eceBPF Map\u5f00\u59cb\uff0c\u4e86\u89e3\u5982 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1317],"tags":[877,1318,1326],"_links":{"self":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8040"}],"collection":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8040"}],"version-history":[{"count":4,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8040\/revisions"}],"predecessor-version":[{"id":8054,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8040\/revisions\/8054"}],"wp:attachment":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8040"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8040"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}