{"id":4140,"date":"2012-08-25T13:27:07","date_gmt":"2012-08-25T05:27:07","guid":{"rendered":"http:\/\/edsionte.com\/techblog\/?p=4140"},"modified":"2012-08-25T13:42:37","modified_gmt":"2012-08-25T05:42:37","slug":"netlink%e7%bc%96%e7%a8%8b-%e4%bd%bf%e7%94%a8netlink_inet_diag%e5%8d%8f%e8%ae%ae%e8%bf%9b%e8%a1%8c%e6%95%b0%e6%8d%ae%e4%ba%a4%e4%ba%92","status":"publish","type":"post","link":"http:\/\/edsionte.com\/techblog\/archives\/4140","title":{"rendered":"Netlink\u7f16\u7a0b-\u4f7f\u7528NETLINK_INET_DIAG\u534f\u8bae"},"content":{"rendered":"<p>Netlink\u53ef\u4ee5\u4f7f\u5f97\u5185\u6838\u548c\u7528\u6237\u8fdb\u7a0b\u8fdb\u884c\u53cc\u5411\u901a\u4fe1\uff0c\u524d\u6587\u5df2\u7ecf\u4ecb\u7ecd\u8fc7\u7528\u6237\u8fdb\u7a0b\u4e3b\u52a8\u53d1\u8d77\u4f1a\u8bdd\u8bf7\u6c42\u7684\u4f8b\u5b50\u3002\u5728\u90a3\u4e2a\u793a\u4f8b\u7a0b\u5e8f\u4e2d\uff0c\u5fc5\u987b\u540c\u65f6\u7f16\u5199\u7528\u6237\u6001\u7a0b\u5e8f\u548c\u5185\u6838\u6a21\u5757\uff0c\u56e0\u4e3a\u4ed6\u4eec\u4e4b\u95f4\u901a\u4fe1\u7684\u534f\u8bae\u662f\u6211\u4eec\u81ea\u5df1\u8bbe\u5b9a\u7684\uff0c\u5e76\u6ca1\u6709\u4f7f\u7528netlink\u5df2\u6709\u7684\u901a\u4fe1\u534f\u8bae\u3002\u5982\u679c\u4f7f\u7528netlink\u5df2\u6709\u7684\u901a\u4fe1\u534f\u8bae\uff0c\u90a3\u4e48\u6211\u4eec\u65e0\u9700\u7f16\u5199\u5185\u6838\u6a21\u5757\uff0c\u53ea\u9700\u7f16\u5199\u7528\u6237\u6001\u7a0b\u5e8f\u5373\u53ef\u3002<\/p>\n<p>\u672c\u6587\u5c06\u8bf4\u660e\u5982\u4f55\u5728\u7528\u6237\u6001\u4f7f\u7528NETLINK_INET_DIAG\u534f\u8bae\u3002<\/p>\n<h4>1.\u521b\u5efanetlink\u5957\u63a5\u5b57<\/h4>\n<p>Netlink\u7684\u4f7f\u7528\u65b9\u6cd5\u4e0e\u666e\u901a\u5957\u63a5\u5b57\u5e76\u65e0\u592a\u5927\u5dee\u5f02\uff0c\u524d\u6587\u5df2\u7ecf\u8bf4\u660e\u53c2\u6570\u7684\u5dee\u5f02\uff0c\u8fd9\u91cc\u4e0d\u518d\u8d58\u8ff0\u3002<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\nstruct sk_req {\r\n\tstruct nlmsghdr nlh;\r\n\tstruct inet_diag_req r;\r\n};\r\n\r\nint main(int argc, char **argv)\r\n{\r\n\tint fd;\r\n\tstruct sk_req req;\r\n\tstruct sockaddr_nl dest_addr;\r\n\tstruct msghdr msg;\r\n\tchar buf&#x5B;8192];\r\n\tchar src_ip&#x5B;20];\r\n\tchar dest_ip&#x5B;20];\r\n\tstruct iovec iov;\r\n\r\n\tif ((fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_INET_DIAG)) &lt; 0) {\r\n\t\teprint(__LINE__, errno, &quot;socket&quot;);\r\n\t\treturn -1;\r\n\t}\r\n<\/pre>\n<h4>2.\u53d1\u9001\u6d88\u606f\u5230\u5185\u6838<\/h4>\n<p>\u7528\u6237\u8fdb\u7a0b\u901a\u8fc7msghdr\u7ed3\u6784\u5c06\u6d88\u606f\u53d1\u9001\u5230\u5185\u6838\u4e2d\uff0c\u56e0\u6b64\u5fc5\u987b\u9996\u5148\u521d\u59cb\u5316msghdr\u7c7b\u578b\u7684\u53d8\u91cfmsg\u3002\u8be5\u6570\u636e\u7ed3\u6784\u4e0eiovec\u7c7b\u578b\u7684\u53d8\u91cfiov\u548csockaddr_nl\u7c7b\u578b\u7684\u53d8\u91cfdest_addr\u5173\u8054\uff0ciov\u6307\u5411\u6570\u636e\u7f13\u51b2\u533a\uff0cdest_addr\u7528\u4e8e\u63cf\u8ff0\u76ee\u7684\u5957\u63a5\u5b57\u5730\u5740\u3002<\/p>\n<p>\u8fd9\u91cc\u9700\u8981\u5c06nlmsghdr\u7ed3\u6784\u4e2d\u7684nlmsg_type\u6307\u5b9a\u4e3aTCPDIAG_GETSOCK\uff0c\u8bf4\u660e\u83b7\u53d6\u7684\u662fTCP\u5957\u63a5\u5b57\u3002\u540c\u65f6\u9700\u8981\u5c06nlmsg_flags\u5b57\u6bb5\u6307\u5b9a\u4e3aNLM_F_REQUEST | \u00a0NLM_F_ROOT\uff0cNLM_F_REQUEST\u662f\u6240\u6709\u5411\u5185\u6838\u53d1\u51fa\u6d88\u606f\u8bf7\u6c42\u7684\u7528\u6237\u8fdb\u7a0b\u6240\u5fc5\u987b\u6240\u8bbe\u7f6e\u7684\uff0cNLM_F_ROOT\u5219\u6307\u660e\u8fd4\u56de\u6240\u6709\u7684\u5957\u63a5\u5b57\u3002<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\n\treq.nlh.nlmsg_len = sizeof(req);\r\n\treq.nlh.nlmsg_type = TCPDIAG_GETSOCK;\r\n\treq.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;\r\n\treq.nlh.nlmsg_pid = 0;\r\n\r\n\tmemset(&amp;req.r, 0, sizeof(req.r));\r\n\treq.r.idiag_family = AF_INET;\r\n\treq.r.idiag_states = ((1 &lt;&lt; TCP_CLOSING + 1) - 1);\r\n\r\n\tiov.iov_base = &amp;req;\r\n\tiov.iov_len = sizeof(req);\r\n\r\n\tmemset(&amp;dest_addr, 0, sizeof(dest_addr));\r\n\tdest_addr.nl_family = AF_NETLINK;\r\n\tdest_addr.nl_pid = 0;\r\n\tdest_addr.nl_groups = 0;\r\n\r\n\tmemset(&amp;msg, 0, sizeof(msg));\r\n\tmsg.msg_name = (void *)&amp;dest_addr;\r\n\tmsg.msg_namelen = sizeof(dest_addr);\r\n\tmsg.msg_iov = &amp;iov;\r\n\tmsg.msg_iovlen = 1;\r\n<\/pre>\n<p>\u6570\u636e\u7f13\u51b2\u533a\u901a\u8fc7req\u7ed3\u6784\u6765\u8868\u793a\uff0c\u5b83\u5c01\u88c5\u4e86\u4e24\u4e2a\u6570\u636e\u7ed3\u6784nlmsghdr\u548cinet_diag_req\u3002\u524d\u8005\u7528\u6765\u8868\u793anetlink\u6d88\u606f\u5934\uff0c\u5b83\u662f\u5fc5\u987b\u5c01\u88c5\u7684\u6570\u636e\u7ed3\u6784\u3002\u540e\u8005\u662fNETLINK_INET_DIAG\u534f\u8bae\u6240\u7279\u6709\u7684\u8bf7\u6c42\u4f1a\u8bdd\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5177\u4f53\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\nstruct inet_diag_req {\r\n        __u8    idiag_family;           \/* Family of addresses. *\/\r\n        __u8    idiag_src_len;\r\n        __u8    idiag_dst_len;\r\n        __u8    idiag_ext;              \/* Query extended information *\/\r\n\r\n        struct inet_diag_sockid id;\r\n\r\n        __u32   idiag_states;           \/* States to dump *\/\r\n        __u32   idiag_dbs;              \/* Tables to dump (NI) *\/\r\n};\r\n<\/pre>\n<p>\u8fd9\u91cc\u9700\u8981\u7279\u522b\u6ce8\u610f\u7684\u662finet_diag_req\u7ed3\u6784\u4e2d\u7684idiag_states\u5b57\u6bb5\uff0c\u5b83\u7528\u6765\u8868\u793a\u5185\u6838\u5c06\u8981\u53cd\u9988\u54ea\u4e9b\u72b6\u6001\u7684\u5957\u63a5\u5b57\u5230\u7528\u6237\u7a7a\u95f4\u3002\u7528\u6237\u7a7a\u95f4\u901a\u8fc7\u4e00\u4e2a\u679a\u4e3e\u7c7b\u578b\u6765\u8868\u793a\u5957\u63a5\u5b57\u72b6\u6001\uff1a<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\nenum\r\n{\r\n  TCP_ESTABLISHED = 1,\r\n  TCP_SYN_SENT,\r\n  TCP_SYN_RECV,\r\n  TCP_FIN_WAIT1,\r\n  TCP_FIN_WAIT2,\r\n  TCP_TIME_WAIT,\r\n  TCP_CLOSE,\r\n  TCP_CLOSE_WAIT,\r\n  TCP_LAST_ACK,\r\n  TCP_LISTEN,\r\n  TCP_CLOSING\r\n};\r\n<\/pre>\n<p>idiag_states\u5b57\u6bb5\u7684\u6bcf\u4e00\u4f4d\u8868\u793a\u4e00\u4e2a\u72b6\u6001\uff0c\u56e0\u6b64\u901a\u8fc7\u4f4d\u504f\u79fb\u53ef\u4ee5\u5c06\u5177\u4f53\u67d0\u4e2a\u72b6\u6001\u4f4d\u7f6e1\u3002\u4e0a\u8ff0\u7684\u5b9e\u4f8b\u7a0b\u5e8f\u4e2d\uff0c\u5c06\u8868\u793a\u6240\u6709\u72b6\u6001\u7684\u4f4d\u90fd\u7f6e1\uff0c\u56e0\u6b64\u5185\u6838\u5c06\u5411\u7528\u6237\u8fdb\u7a0b\u53cd\u9988\u6240\u6709\u72b6\u6001\u7684\u5957\u63a5\u5b57\u3002<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\n\tif (sendmsg(fd, &amp;msg, 0) &lt; 0) {\r\n\t\teprint(__LINE__, errno, &quot;sendmsg&quot;);\r\n\t\treturn -1;\r\n\t}\r\n<\/pre>\n<p>\u521d\u59cb\u5316\u76f8\u5173\u7684\u6570\u636e\u7ed3\u6784\u4e4b\u540e\uff0c\u63a5\u4e0b\u6765\u7528\u6237\u8fdb\u7a0b\u901a\u8fc7sendmsg\u51fd\u6570\u53d1\u9001\u6d88\u606f\u5230\u5185\u6838\u4e2d\u3002<\/p>\n<h4>3.\u7528\u6237\u8fdb\u7a0b\u63a5\u6536\u6d88\u606f<\/h4>\n<p>\u7528\u6237\u8fdb\u7a0b\u901a\u8fc7\u4e24\u5c42\u5faa\u73af\u6765\u63a5\u53d7\u5e76\u5904\u7406\u5185\u6838\u53d1\u9001\u7684\u6d88\u606f\u3002\u5916\u5c42\u5faa\u73af\u901a\u8fc7recvmsg\u51fd\u6570\u4e0d\u65ad\u63a5\u6536\u5185\u6838\u53d1\u9001\u7684\u6570\u636e\uff0c\u5728\u63a5\u6536\u6570\u636e\u4e4b\u524d\u8fd8\u8981\u5c06\u65b0\u7684\u6570\u636e\u7f13\u51b2\u533abuf\u4e0eiov\u8fdb\u884c\u7ed1\u5b9a\u3002\u5185\u5c42\u5faa\u73af\u5c06\u5185\u6838\u901a\u8fc7\u4e00\u6b21\u7cfb\u7edf\u8c03\u7528\u6240\u53d1\u9001\u7684\u6570\u636e\u8fdb\u884c\u5206\u6279\u5904\u7406\u3002\u5bf9\u4e8e\u672c\u6587\u6240\u63cf\u8ff0\u7684NETLINK_INET_DIAG\u534f\u8bae\uff0c\u5185\u6838\u6bcf\u6b21\u5411\u7528\u6237\u8fdb\u7a0b\u53d1\u9001\u7684\u6d88\u606f\u901a\u8fc7inet_diag_msg\u7ed3\u6784\u63cf\u8ff0\uff1a<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\nstruct inet_diag_msg {\r\n        __u8    idiag_family;\r\n        __u8    idiag_state;\r\n        __u8    idiag_timer;\r\n        __u8    idiag_retrans;\r\n\r\n        struct inet_diag_sockid id;\r\n\r\n        __u32   idiag_expires;\r\n        __u32   idiag_rqueue;\r\n        __u32   idiag_wqueue;\r\n        __u32   idiag_uid;\r\n        __u32   idiag_inode;\r\n};\r\n<\/pre>\n<p>\u6bcf\u4e00\u6b21\u5916\u5c42\u5faa\u73af\u5c06\u63a5\u6536\u5230\u7684\u6570\u636e\u5b58\u653e\u5728buf\u7f13\u51b2\u533a\u4e2d\uff0c\u8be5\u7f13\u51b2\u533a\u4e2d\u5b58\u653e\u4e86\u591a\u6761\u6d88\u606f\uff0c\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\nstruct nlhdrmsg struct inet_idiag_msg || struct nlhdrmsg struct inet_idiag_msg || \u2026\u2026\r\n<\/pre>\n<p>\u6309\u7167\u8fd9\u6837\u7684\u6570\u636e\u5b58\u50a8\u65b9\u5f0f\uff0c\u5185\u5c42\u5faa\u73af\u8981\u505a\u7684\u5c31\u662f\u4f9d\u6b21\u83b7\u53d6\u8fd9\u4e9b\u6570\u636e\u7ed3\u6784\u3002\u7531\u4e8e\u6bcf\u6761\u6570\u636e\u62a5\u90fd\u81f3\u5c11\u5c01\u88c5\u4e86nlmsghdr\u7ed3\u6784\uff0c\u56e0\u6b64\u5177\u4f53\u7684\u5904\u7406\u65b9\u6cd5\u901a\u8fc7NLMSG_XXX\u5b8f\u5373\u53ef\u5b8c\u6210\u3002<\/p>\n<pre class=\"brush: cpp; title: ; notranslate\" title=\"\">\r\n\tmemset(buf, 0 ,sizeof(buf));\r\n\tiov.iov_base = buf;\r\n\tiov.iov_len = sizeof(buf);\r\n\r\n\twhile (1) {\r\n\t\tint status;\r\n\t\tstruct nlmsghdr *h;\r\n\r\n\t\tmsg = (struct msghdr) {\r\n\t\t\t(void *)&amp;dest_addr, sizeof(dest_addr),\r\n\t\t\t\t&amp;iov, 1, NULL, 0, 0\r\n\t\t};\r\n\t\tstatus = recvmsg(fd, &amp;msg, 0);\r\n\t\tif (status &lt; 0) {\r\n\t\t\tif (errno == EINTR)\r\n\t\t\t\tcontinue;\r\n\t\t\teprint(__LINE__, errno, &quot;recvmsg&quot;);\r\n\t\t\tcontinue;\r\n\t\t}\r\n\r\n\t\tif (status == 0) {\r\n\t\t\tprintf(&quot;EOF on netlink\\n&quot;);\r\n\t\t\tclose(fd);\r\n\t\t\treturn 0;\r\n\t\t}\r\n\r\n\t\th = (struct nlmsghdr *)buf;\r\n\r\n\t\twhile (NLMSG_OK(h, status)) {\r\n\t\t\tstruct inet_diag_msg *pkg = NULL;\r\n\r\n\t\t\tif (h-&gt;nlmsg_type == NLMSG_DONE) {\r\n\t\t\t\tclose(fd);\r\n\t\t\t\tprintf(&quot;NLMSG_DONE\\n&quot;);\r\n\t\t\t\treturn 0;\r\n\t\t\t}\r\n\r\n\t\t\tif (h-&gt;nlmsg_type == NLMSG_ERROR) {\r\n\t\t\t\tstruct nlmsgerr *err;\r\n\t\t\t\terr = (struct nlmsgerr*)NLMSG_DATA(h);\r\n\t\t\t\tfprintf(stderr, &quot;%d Error %d:%s\\n&quot;, __LINE__, -(err-&gt;error), strerror(-(err-&gt;error)));\r\n\t\t\t\tclose(fd);\r\n\t\t\t\tprintf(&quot;NLMSG_ERROR\\n&quot;);\r\n\t\t\t\treturn 0;\r\n\t\t\t}\r\n\r\n\t\t\tpkg = (struct inet_diag_msg *)NLMSG_DATA(h);\r\n\t\t\tprint_skinfo(pkg);\r\n\t\t\tget_tcp_state(pkg-&gt;idiag_state);\r\n\t\t\th = NLMSG_NEXT(h, status);\r\n\t\t}\/\/while\r\n\t}\/\/while\r\n\tclose(fd);\r\n\treturn 0;\r\n<\/pre>\n<p>NLMSG_OK\u5b8f\u6bcf\u6b21\u5224\u65adbuf\u4e2d\u7684\u6570\u636e\u662f\u5426\u8bfb\u53d6\u5b8c\u6bd5\uff0cNLMSG_DATA\u53d6\u5f53\u524dnetlink\u6d88\u606f\u5934\u7ed3\u6784\u7d27\u90bb\u7684inet_diag_msg\u7ed3\u6784\uff0cNLMSG_NEXT\u5219\u53d6\u4e0b\u4e00\u4e2anetlink\u6d88\u606f\u5934\u7ed3\u6784\u3002<\/p>\n<p>pkg\u6307\u5411\u5f53\u524d\u83b7\u53d6\u5230\u7684\u6d88\u606f\uff0c\u63a5\u4e0b\u6765\u5177\u4f53\u9700\u6c42\u5904\u7406\u5404\u4e2a\u5b57\u6bb5\u5373\u53ef\u3002\u4e0a\u8ff0\u7a0b\u5e8f\u4e2d\uff0cprint_skinfo\u51fd\u6570\u6253\u5370pkg\u4e2d\u7684\u5404\u4e2a\u5b57\u6bb5\uff0cget_tcp_state\u5219\u662f\u6253\u5370\u6bcf\u4e2a\u5957\u63a5\u5b57\u8fde\u63a5\u7684\u72b6\u6001\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Netlink\u53ef\u4ee5\u4f7f\u5f97\u5185\u6838\u548c\u7528\u6237\u8fdb\u7a0b\u8fdb\u884c\u53cc\u5411\u901a\u4fe1\uff0c\u524d\u6587\u5df2\u7ecf\u4ecb\u7ecd\u8fc7\u7528\u6237\u8fdb\u7a0b\u4e3b\u52a8\u53d1\u8d77\u4f1a\u8bdd\u8bf7\u6c42\u7684\u4f8b\u5b50\u3002\u5728\u90a3\u4e2a\u793a\u4f8b\u7a0b\u5e8f [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[353],"tags":[354,356,405],"class_list":["post-4140","post","type-post","status-publish","format-standard","hentry","category-netlink","tag-netlink","tag-356","tag-405"],"views":12644,"_links":{"self":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/4140","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/comments?post=4140"}],"version-history":[{"count":0,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/4140\/revisions"}],"wp:attachment":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/media?parent=4140"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/categories?post=4140"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/tags?post=4140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}