{ "mode": "info", "parameter": "SOCK_DIAG", "section": "", "url": "https://www.chedong.com/phpMan.php/info/SOCK_DIAG/json", "generated": "2026-07-05T23:22:47Z", "synopsis": "#include \n#include \n#include /* for UNIX domain sockets */\n#include /* for IPv4 and IPv6 sockets */\ndiagsocket = socket(AFNETLINK, sockettype, NETLINKSOCKDIAG);", "sections": { "NAME": { "content": "sockdiag - obtaining information about sockets\n", "subsections": [] }, "SYNOPSIS": { "content": "#include \n#include \n#include /* for UNIX domain sockets */\n#include /* for IPv4 and IPv6 sockets */\n\ndiagsocket = socket(AFNETLINK, sockettype, NETLINKSOCKDIAG);\n", "subsections": [] }, "DESCRIPTION": { "content": "The sockdiag netlink subsystem provides a mechanism for obtaining in-\nformation about sockets of various address families from the kernel.\nThis subsystem can be used to obtain information about individual sock-\nets or request a list of sockets.\n\nIn the request, the caller can specify additional information it would\nlike to obtain about the socket, for example, memory information or in-\nformation specific to the address family.\n\nWhen requesting a list of sockets, the caller can specify filters that\nwould be applied by the kernel to select a subset of sockets to report.\nFor now, there is only the ability to filter sockets by state (con-\nnected, listening, and so on.)\n\nNote that sockdiag reports only those sockets that have a name; that\nis, either sockets bound explicitly with bind(2) or sockets that were\nautomatically bound to an address (e.g., by connect(2)). This is the\nsame set of sockets that is available via /proc/net/unix,\n/proc/net/tcp, /proc/net/udp, and so on.\n\nRequest\nThe request starts with a struct nlmsghdr header described in\nnetlink(7) with nlmsgtype field set to SOCKDIAGBYFAMILY. It is\nfollowed by a header specific to the address family that starts with a\ncommon part shared by all address families:\n\nstruct sockdiagreq {\nu8 sdiagfamily;\nu8 sdiagprotocol;\n};\n\nThe fields of this structure are as follows:\n\nsdiagfamily\nAn address family. It should be set to the appropriate AF*\nconstant.\n\nsdiagprotocol\nDepends on sdiagfamily. It should be set to the appropriate\nIPPROTO* constant for AFINET and AFINET6, and to 0 otherwise.\n\nIf the nlmsgflags field of the struct nlmsghdr header has the\nNLMFDUMP flag set, it means that a list of sockets is being re-\nquested; otherwise it is a query about an individual socket.\n\nResponse\nThe response starts with a struct nlmsghdr header and is followed by an\narray of objects specific to the address family. The array is to be\naccessed with the standard NLMSG* macros from the netlink(3) API.\n\nEach object is the NLA (netlink attributes) list that is to be accessed\nwith the RTA* macros from rtnetlink(3) API.\n\nUNIX domain sockets\nFor UNIX domain sockets the request is represented in the following\nstructure:\n\nstruct unixdiagreq {\nu8 sdiagfamily;\nu8 sdiagprotocol;\nu16 pad;\nu32 udiagstates;\nu32 udiagino;\nu32 udiagshow;\nu32 udiagcookie[2];\n};\n\nThe fields of this structure are as follows:\n\nsdiagfamily\nThe address family; it should be set to AFUNIX.\n\nsdiagprotocol\npad These fields should be set to 0.\n\nudiagstates\nThis is a bit mask that defines a filter of sockets states.\nOnly those sockets whose states are in this mask will be re-\nported. Ignored when querying for an individual socket. Sup-\nported values are:\n\n1 << TCPESTABLISHED\n\n1 << TCPLISTEN\n\nudiagino\nThis is an inode number when querying for an individual socket.\nIgnored when querying for a list of sockets.\n\nudiagshow\nThis is a set of flags defining what kind of information to re-\nport. Each requested kind of information is reported back as a\nnetlink attribute as described below:\n\nUDIAGSHOWNAME\nThe attribute reported in answer to this request is\nUNIXDIAGNAME. The payload associated with this attri-\nbute is the pathname to which the socket was bound (a se-\nquence of bytes up to UNIXPATHMAX length).\n\nUDIAGSHOWVFS\nThe attribute reported in answer to this request is\nUNIXDIAGVFS. The payload associated with this attri-\nbute is represented in the following structure:\n\nstruct unixdiagvfs {\nu32 udiagvfsdev;\nu32 udiagvfsino;\n};\n\nThe fields of this structure are as follows:\n\nudiagvfsdev\nThe device number of the corresponding on-disk\nsocket inode.\n\nudiagvfsino\nThe inode number of the corresponding on-disk\nsocket inode.\n\nUDIAGSHOWPEER\nThe attribute reported in answer to this request is\nUNIXDIAGPEER. The payload associated with this attri-\nbute is a u32 value which is the peer's inode number.\nThis attribute is reported for connected sockets only.\n\nUDIAGSHOWICONS\nThe attribute reported in answer to this request is\nUNIXDIAGICONS. The payload associated with this attri-\nbute is an array of u32 values which are inode numbers\nof sockets that has passed the connect(2) call, but\nhasn't been processed with accept(2) yet. This attribute\nis reported for listening sockets only.\n\nUDIAGSHOWRQLEN\nThe attribute reported in answer to this request is\nUNIXDIAGRQLEN. The payload associated with this attri-\nbute is represented in the following structure:\n\nstruct unixdiagrqlen {\nu32 udiagrqueue;\nu32 udiagwqueue;\n};\n\nThe fields of this structure are as follows:\n\nudiagrqueue\nFor listening sockets: the number of pending con-\nnections. The length of the array associated with\nthe UNIXDIAGICONS response attribute is equal to\nthis value.\n\nFor established sockets: the amount of data in in-\ncoming queue.\n\nudiagwqueue\nFor listening sockets: the backlog length which\nequals to the value passed as the second argument\nto listen(2).\n\nFor established sockets: the amount of memory\navailable for sending.\n\nUDIAGSHOWMEMINFO\nThe attribute reported in answer to this request is\nUNIXDIAGMEMINFO. The payload associated with this at-\ntribute is an array of u32 values described below in\nthe subsection \"Socket memory information\".\n\nThe following attributes are reported back without any specific\nrequest:\n\nUNIXDIAGSHUTDOWN\nThe payload associated with this attribute is u8 value\nwhich represents bits of shutdown(2) state.\n\nudiagcookie\nThis is an array of opaque identifiers that could be used along\nwith udiagino to specify an individual socket. It is ignored\nwhen querying for a list of sockets, as well as when all its el-\nements are set to -1.\n\nThe response to a query for UNIX domain sockets is represented as an\narray of\n\nstruct unixdiagmsg {\nu8 udiagfamily;\nu8 udiagtype;\nu8 udiagstate;\nu8 pad;\nu32 udiagino;\nu32 udiagcookie[2];\n};\n\nfollowed by netlink attributes.\n\nThe fields of this structure are as follows:\n\nudiagfamily\nThis field has the same meaning as in struct unixdiagreq.\n\nudiagtype\nThis is set to one of SOCKPACKET, SOCKSTREAM, or SOCKSEQ-\nPACKET.\n\nudiagstate\nThis is set to one of TCPLISTEN or TCPESTABLISHED.\n\npad This field is set to 0.\n\nudiagino\nThis is the socket inode number.\n\nudiagcookie\nThis is an array of opaque identifiers that could be used in\nsubsequent queries.\n\nIPv4 and IPv6 sockets\nFor IPv4 and IPv6 sockets, the request is represented in the following\nstructure:\n\nstruct inetdiagreqv2 {\nu8 sdiagfamily;\nu8 sdiagprotocol;\nu8 idiagext;\nu8 pad;\nu32 idiagstates;\nstruct inetdiagsockid id;\n};\n\nwhere struct inetdiagsockid is defined as follows:\n\nstruct inetdiagsockid {\nbe16 idiagsport;\nbe16 idiagdport;\nbe32 idiagsrc[4];\nbe32 idiagdst[4];\nu32 idiagif;\nu32 idiagcookie[2];\n};\n\nThe fields of struct inetdiagreqv2 are as follows:\n\nsdiagfamily\nThis should be set to either AFINET or AFINET6 for IPv4 or\nIPv6 sockets respectively.\n\nsdiagprotocol\nThis should be set to one of IPPROTOTCP, IPPROTOUDP, or IP-\nPROTOUDPLITE.\n\nidiagext\nThis is a set of flags defining what kind of extended informa-\ntion to report. Each requested kind of information is reported\nback as a netlink attribute as described below:\n\nINETDIAGTOS\nThe payload associated with this attribute is a u8\nvalue which is the TOS of the socket.\n\nINETDIAGTCLASS\nThe payload associated with this attribute is a u8\nvalue which is the TClass of the socket. IPv6 sockets\nonly. For LISTEN and CLOSE sockets, this is followed by\nINETDIAGSKV6ONLY attribute with associated u8 payload\nvalue meaning whether the socket is IPv6-only or not.\n\nINETDIAGMEMINFO\nThe payload associated with this attribute is represented\nin the following structure:\n\nstruct inetdiagmeminfo {\nu32 idiagrmem;\nu32 idiagwmem;\nu32 idiagfmem;\nu32 idiagtmem;\n};\n\nThe fields of this structure are as follows:\n\nidiagrmem The amount of data in the receive queue.\n\nidiagwmem The amount of data that is queued by TCP but\nnot yet sent.\n\nidiagfmem The amount of memory scheduled for future use\n(TCP only).\n\nidiagtmem The amount of data in send queue.\n\nINETDIAGSKMEMINFO\nThe payload associated with this attribute is an array of\nu32 values described below in the subsection \"Socket\nmemory information\".\n\nINETDIAGINFO\nThe payload associated with this attribute is specific to\nthe address family. For TCP sockets, it is an object of\ntype struct tcpinfo.\n\nINETDIAGCONG\nThe payload associated with this attribute is a string\nthat describes the congestion control algorithm used.\nFor TCP sockets only.\n\npad This should be set to 0.\n\nidiagstates\nThis is a bit mask that defines a filter of socket states. Only\nthose sockets whose states are in this mask will be reported.\nIgnored when querying for an individual socket.\n\nid This is a socket ID object that is used in dump requests, in\nqueries about individual sockets, and is reported back in each\nresponse. Unlike UNIX domain sockets, IPv4 and IPv6 sockets are\nidentified using addresses and ports. All values are in network\nbyte order.\n\nThe fields of struct inetdiagsockid are as follows:\n\nidiagsport\nThe source port.\n\nidiagdport\nThe destination port.\n\nidiagsrc\nThe source address.\n\nidiagdst\nThe destination address.\n\nidiagif\nThe interface number the socket is bound to.\n\nidiagcookie\nThis is an array of opaque identifiers that could be used along\nwith other fields of this structure to specify an individual\nsocket. It is ignored when querying for a list of sockets, as\nwell as when all its elements are set to -1.\n\nThe response to a query for IPv4 or IPv6 sockets is represented as an\narray of\n\nstruct inetdiagmsg {\nu8 idiagfamily;\nu8 idiagstate;\nu8 idiagtimer;\nu8 idiagretrans;\n\nstruct inetdiagsockid id;\n\nu32 idiagexpires;\nu32 idiagrqueue;\nu32 idiagwqueue;\nu32 idiaguid;\nu32 idiaginode;\n};\n\nfollowed by netlink attributes.\n\nThe fields of this structure are as follows:\n\nidiagfamily\nThis is the same field as in struct inetdiagreqv2.\n\nidiagstate\nThis denotes socket state as in struct inetdiagreqv2.\n\nidiagtimer\nFor TCP sockets, this field describes the type of timer that is\ncurrently active for the socket. It is set to one of the fol-\nlowing constants:\n\n0 no timer is active\n1 a retransmit timer\n2 a keep-alive timer\n3 a TIMEWAIT timer\n4 a zero window probe timer\n\nFor non-TCP sockets, this field is set to 0.\n\nidiagretrans\nFor idiagtimer values 1, 2, and 4, this field contains the num-\nber of retransmits. For other idiagtimer values, this field is\nset to 0.\n\nidiagexpires\nFor TCP sockets that have an active timer, this field describes\nits expiration time in milliseconds. For other sockets, this\nfield is set to 0.\n\nidiagrqueue\nFor listening sockets: the number of pending connections.\n\nFor other sockets: the amount of data in the incoming queue.\n\nidiagwqueue\nFor listening sockets: the backlog length.\n\nFor other sockets: the amount of memory available for sending.\n\nidiaguid\nThis is the socket owner UID.\n\nidiaginode\nThis is the socket inode number.\n\nSocket memory information\nThe payload associated with UNIXDIAGMEMINFO and INETDIAGSKMEMINFO\nnetlink attributes is an array of the following u32 values:\n\nSKMEMINFORMEMALLOC\nThe amount of data in receive queue.\n\nSKMEMINFORCVBUF\nThe receive socket buffer as set by SORCVBUF.\n\nSKMEMINFOWMEMALLOC\nThe amount of data in send queue.\n\nSKMEMINFOSNDBUF\nThe send socket buffer as set by SOSNDBUF.\n\nSKMEMINFOFWDALLOC\nThe amount of memory scheduled for future use (TCP only).\n\nSKMEMINFOWMEMQUEUED\nThe amount of data queued by TCP, but not yet sent.\n\nSKMEMINFOOPTMEM\nThe amount of memory allocated for the socket's service needs\n(e.g., socket filter).\n\nSKMEMINFOBACKLOG\nThe amount of packets in the backlog (not yet processed).\n", "subsections": [] }, "VERSIONS": { "content": "NETLINKINETDIAG was introduced in Linux 2.6.14 and supported AFINET\nand AFINET6 sockets only. In Linux 3.3, it was renamed to\nNETLINKSOCKDIAG and extended to support AFUNIX sockets.\n\nUNIXDIAGMEMINFO and INETDIAGSKMEMINFO were introduced in Linux 3.6.\n", "subsections": [] }, "CONFORMING TO": { "content": "The NETLINKSOCKDIAG API is Linux-specific.\n", "subsections": [] }, "EXAMPLES": { "content": "The following example program prints inode number, peer's inode number,\nand name of all UNIX domain sockets in the current namespace.\n\n#include \n#include \n#include \n#include \n#include \n#include \n#include \n#include \n#include \n#include \n\nstatic int\nsendquery(int fd)\n{\nstruct sockaddrnl nladdr = {\n.nlfamily = AFNETLINK\n};\nstruct\n{\nstruct nlmsghdr nlh;\nstruct unixdiagreq udr;\n} req = {\n.nlh = {\n.nlmsglen = sizeof(req),\n.nlmsgtype = SOCKDIAGBYFAMILY,\n.nlmsgflags = NLMFREQUEST | NLMFDUMP\n},\n.udr = {\n.sdiagfamily = AFUNIX,\n.udiagstates = -1,\n.udiagshow = UDIAGSHOWNAME | UDIAGSHOWPEER\n}\n};\nstruct iovec iov = {\n.iovbase = &req,\n.iovlen = sizeof(req)\n};\nstruct msghdr msg = {\n.msgname = &nladdr,\n.msgnamelen = sizeof(nladdr),\n.msgiov = &iov,\n.msgiovlen = 1\n};\n\nfor (;;) {\nif (sendmsg(fd, &msg, 0) < 0) {\nif (errno == EINTR)\ncontinue;\n\nperror(\"sendmsg\");\nreturn -1;\n}\n\nreturn 0;\n}\n}\n\nstatic int\nprintdiag(const struct unixdiagmsg *diag, unsigned int len)\n{\nif (len < NLMSGLENGTH(sizeof(*diag))) {\nfputs(\"short response\\n\", stderr);\nreturn -1;\n}\nif (diag->udiagfamily != AFUNIX) {\nfprintf(stderr, \"unexpected family %u\\n\", diag->udiagfamily);\nreturn -1;\n}\n\nunsigned int rtalen = len - NLMSGLENGTH(sizeof(*diag));\nunsigned int peer = 0;\nsizet pathlen = 0;\nchar path[sizeof(((struct sockaddrun *) 0)->sunpath) + 1];\n\nfor (struct rtattr *attr = (struct rtattr *) (diag + 1);\nRTAOK(attr, rtalen); attr = RTANEXT(attr, rtalen)) {\nswitch (attr->rtatype) {\ncase UNIXDIAGNAME:\nif (!pathlen) {\npathlen = RTAPAYLOAD(attr);\nif (pathlen > sizeof(path) - 1)\npathlen = sizeof(path) - 1;\nmemcpy(path, RTADATA(attr), pathlen);\npath[pathlen] = '\\0';\n}\nbreak;\n\ncase UNIXDIAGPEER:\nif (RTAPAYLOAD(attr) >= sizeof(peer))\npeer = *(unsigned int *) RTADATA(attr);\nbreak;\n}\n}\n\nprintf(\"inode=%u\", diag->udiagino);\n\nif (peer)\nprintf(\", peer=%u\", peer);\n\nif (pathlen)\nprintf(\", name=%s%s\", *path ? \"\" : \"@\",\n*path ? path : path + 1);\n\nputchar('\\n');\nreturn 0;\n}\n\nstatic int\nreceiveresponses(int fd)\n{\nlong buf[8192 / sizeof(long)];\nstruct sockaddrnl nladdr = {\n.nlfamily = AFNETLINK\n};\nstruct iovec iov = {\n.iovbase = buf,\n.iovlen = sizeof(buf)\n};\nint flags = 0;\n\nfor (;;) {\nstruct msghdr msg = {\n.msgname = &nladdr,\n.msgnamelen = sizeof(nladdr),\n.msgiov = &iov,\n.msgiovlen = 1\n};\n\nssizet ret = recvmsg(fd, &msg, flags);\n\nif (ret < 0) {\nif (errno == EINTR)\ncontinue;\n\nperror(\"recvmsg\");\nreturn -1;\n}\nif (ret == 0)\nreturn 0;\n\nconst struct nlmsghdr *h = (struct nlmsghdr *) buf;\n\nif (!NLMSGOK(h, ret)) {\nfputs(\"!NLMSGOK\\n\", stderr);\nreturn -1;\n}\n\nfor (; NLMSGOK(h, ret); h = NLMSGNEXT(h, ret)) {\nif (h->nlmsgtype == NLMSGDONE)\nreturn 0;\n\nif (h->nlmsgtype == NLMSGERROR) {\nconst struct nlmsgerr *err = NLMSGDATA(h);\n\nif (h->nlmsglen < NLMSGLENGTH(sizeof(*err))) {\nfputs(\"NLMSGERROR\\n\", stderr);\n} else {\nerrno = -err->error;\nperror(\"NLMSGERROR\");\n}\n\nreturn -1;\n}\n\nif (h->nlmsgtype != SOCKDIAGBYFAMILY) {\nfprintf(stderr, \"unexpected nlmsgtype %u\\n\",\n(unsigned) h->nlmsgtype);\nreturn -1;\n}\n\nif (printdiag(NLMSGDATA(h), h->nlmsglen))\nreturn -1;\n}\n}\n}\n\nint\nmain(void)\n{\nint fd = socket(AFNETLINK, SOCKRAW, NETLINKSOCKDIAG);\n\nif (fd < 0) {\nperror(\"socket\");\nreturn 1;\n}\n\nint ret = sendquery(fd) || receiveresponses(fd);\n\nclose(fd);\nreturn ret;\n}\n", "subsections": [] }, "SEE ALSO": { "content": "netlink(3), rtnetlink(3), netlink(7), tcp(7)\n", "subsections": [] }, "COLOPHON": { "content": "This page is part of release 5.10 of the Linux man-pages project. A\ndescription of the project, information about reporting bugs, and the\nlatest version of this page, can be found at\nhttps://www.kernel.org/doc/man-pages/.\n\nLinux 2020-11-01 SOCKDIAG(7)", "subsections": [] } }, "summary": "sockdiag - obtaining information about sockets", "flags": [], "examples": [ "The following example program prints inode number, peer's inode number,", "and name of all UNIX domain sockets in the current namespace.", "#include ", "#include ", "#include ", "#include ", "#include ", "#include ", "#include ", "#include ", "#include ", "#include ", "static int", "sendquery(int fd)", "struct sockaddrnl nladdr = {", ".nlfamily = AFNETLINK", "};", "struct", "struct nlmsghdr nlh;", "struct unixdiagreq udr;", "} req = {", ".nlh = {", ".nlmsglen = sizeof(req),", ".nlmsgtype = SOCKDIAGBYFAMILY,", ".nlmsgflags = NLMFREQUEST | NLMFDUMP", "},", ".udr = {", ".sdiagfamily = AFUNIX,", ".udiagstates = -1,", ".udiagshow = UDIAGSHOWNAME | UDIAGSHOWPEER", "};", "struct iovec iov = {", ".iovbase = &req,", ".iovlen = sizeof(req)", "};", "struct msghdr msg = {", ".msgname = &nladdr,", ".msgnamelen = sizeof(nladdr),", ".msgiov = &iov,", ".msgiovlen = 1", "};", "for (;;) {", "if (sendmsg(fd, &msg, 0) < 0) {", "if (errno == EINTR)", "continue;", "perror(\"sendmsg\");", "return -1;", "return 0;", "static int", "printdiag(const struct unixdiagmsg *diag, unsigned int len)", "if (len < NLMSGLENGTH(sizeof(*diag))) {", "fputs(\"short response\\n\", stderr);", "return -1;", "if (diag->udiagfamily != AFUNIX) {", "fprintf(stderr, \"unexpected family %u\\n\", diag->udiagfamily);", "return -1;", "unsigned int rtalen = len - NLMSGLENGTH(sizeof(*diag));", "unsigned int peer = 0;", "sizet pathlen = 0;", "char path[sizeof(((struct sockaddrun *) 0)->sunpath) + 1];", "for (struct rtattr *attr = (struct rtattr *) (diag + 1);", "RTAOK(attr, rtalen); attr = RTANEXT(attr, rtalen)) {", "switch (attr->rtatype) {", "case UNIXDIAGNAME:", "if (!pathlen) {", "pathlen = RTAPAYLOAD(attr);", "if (pathlen > sizeof(path) - 1)", "pathlen = sizeof(path) - 1;", "memcpy(path, RTADATA(attr), pathlen);", "path[pathlen] = '\\0';", "break;", "case UNIXDIAGPEER:", "if (RTAPAYLOAD(attr) >= sizeof(peer))", "peer = *(unsigned int *) RTADATA(attr);", "break;", "printf(\"inode=%u\", diag->udiagino);", "if (peer)", "printf(\", peer=%u\", peer);", "if (pathlen)", "printf(\", name=%s%s\", *path ? \"\" : \"@\",", "*path ? path : path + 1);", "putchar('\\n');", "return 0;", "static int", "receiveresponses(int fd)", "long buf[8192 / sizeof(long)];", "struct sockaddrnl nladdr = {", ".nlfamily = AFNETLINK", "};", "struct iovec iov = {", ".iovbase = buf,", ".iovlen = sizeof(buf)", "};", "int flags = 0;", "for (;;) {", "struct msghdr msg = {", ".msgname = &nladdr,", ".msgnamelen = sizeof(nladdr),", ".msgiov = &iov,", ".msgiovlen = 1", "};", "ssizet ret = recvmsg(fd, &msg, flags);", "if (ret < 0) {", "if (errno == EINTR)", "continue;", "perror(\"recvmsg\");", "return -1;", "if (ret == 0)", "return 0;", "const struct nlmsghdr *h = (struct nlmsghdr *) buf;", "if (!NLMSGOK(h, ret)) {", "fputs(\"!NLMSGOK\\n\", stderr);", "return -1;", "for (; NLMSGOK(h, ret); h = NLMSGNEXT(h, ret)) {", "if (h->nlmsgtype == NLMSGDONE)", "return 0;", "if (h->nlmsgtype == NLMSGERROR) {", "const struct nlmsgerr *err = NLMSGDATA(h);", "if (h->nlmsglen < NLMSGLENGTH(sizeof(*err))) {", "fputs(\"NLMSGERROR\\n\", stderr);", "} else {", "errno = -err->error;", "perror(\"NLMSGERROR\");", "return -1;", "if (h->nlmsgtype != SOCKDIAGBYFAMILY) {", "fprintf(stderr, \"unexpected nlmsgtype %u\\n\",", "(unsigned) h->nlmsgtype);", "return -1;", "if (printdiag(NLMSGDATA(h), h->nlmsglen))", "return -1;", "int", "main(void)", "int fd = socket(AFNETLINK, SOCKRAW, NETLINKSOCKDIAG);", "if (fd < 0) {", "perror(\"socket\");", "return 1;", "int ret = sendquery(fd) || receiveresponses(fd);", "close(fd);", "return ret;" ], "see_also": [ { "name": "netlink", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/netlink/3/json" }, { "name": "rtnetlink", "section": "3", "url": "https://www.chedong.com/phpMan.php/man/rtnetlink/3/json" }, { "name": "netlink", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/netlink/7/json" }, { "name": "tcp", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/tcp/7/json" } ] }