1 /* 2 * Copyright (c) 2014-2015 Dmitry V. Levin <ldv (at) altlinux.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <assert.h> 29 #include <stddef.h> 30 #include <stdint.h> 31 #include <string.h> 32 #include <unistd.h> 33 #include <sys/socket.h> 34 #include <sys/un.h> 35 #include <linux/netlink.h> 36 #include <linux/sock_diag.h> 37 #include <linux/unix_diag.h> 38 39 #if !defined NETLINK_SOCK_DIAG && defined NETLINK_INET_DIAG 40 # define NETLINK_SOCK_DIAG NETLINK_INET_DIAG 41 #endif 42 43 static int 44 send_query(const int fd, const int family, const int proto) 45 { 46 struct sockaddr_nl nladdr = { 47 .nl_family = AF_NETLINK 48 }; 49 struct { 50 struct nlmsghdr nlh; 51 struct unix_diag_req udr; 52 } req = { 53 .nlh = { 54 .nlmsg_len = sizeof(req), 55 .nlmsg_type = SOCK_DIAG_BY_FAMILY, 56 .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST 57 }, 58 .udr = { 59 .sdiag_family = family, 60 .sdiag_protocol = proto, 61 .udiag_states = -1, 62 .udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER 63 } 64 }; 65 struct iovec iov = { 66 .iov_base = &req, 67 .iov_len = sizeof(req) 68 }; 69 struct msghdr msg = { 70 .msg_name = (void*)&nladdr, 71 .msg_namelen = sizeof(nladdr), 72 .msg_iov = &iov, 73 .msg_iovlen = 1 74 }; 75 76 return sendmsg(fd, &msg, 0) > 0; 77 } 78 79 static int 80 check_responses(const int fd) 81 { 82 static char buf[8192]; 83 struct sockaddr_nl nladdr = { 84 .nl_family = AF_NETLINK 85 }; 86 struct iovec iov = { 87 .iov_base = buf, 88 .iov_len = sizeof(buf) 89 }; 90 struct msghdr msg = { 91 .msg_name = (void*)&nladdr, 92 .msg_namelen = sizeof(nladdr), 93 .msg_iov = &iov, 94 .msg_iovlen = 1 95 }; 96 97 ssize_t ret = recvmsg(fd, &msg, 0); 98 if (ret <= 0) 99 return 0; 100 101 struct nlmsghdr *h = (struct nlmsghdr*)buf; 102 return (NLMSG_OK(h, ret) && 103 h->nlmsg_type != NLMSG_ERROR && 104 h->nlmsg_type != NLMSG_DONE) ? 1 : 0; 105 } 106 107 #define SUN_PATH "netlink_unix_diag_socket" 108 int main(void) 109 { 110 struct sockaddr_un addr = { 111 .sun_family = AF_UNIX, 112 .sun_path = SUN_PATH 113 }; 114 socklen_t len = offsetof(struct sockaddr_un, sun_path) + sizeof(SUN_PATH); 115 116 close(0); 117 close(1); 118 119 (void) unlink(SUN_PATH); 120 if (socket(PF_LOCAL, SOCK_STREAM, 0) || 121 bind(0, (struct sockaddr *) &addr, len) || 122 listen(0, 5)) 123 return 77; 124 125 assert(unlink(SUN_PATH) == 0); 126 127 if (socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG) != 1) 128 return 77; 129 130 return (send_query(1, AF_UNIX, 0) && 131 check_responses(1)) ? 0 : 77; 132 } 133