| /* Determine whether interfaces use native transport. Linux version. |
| Copyright (C) 2007-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <ifaddrs.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <time.h> |
| #include <unistd.h> |
| #include <net/if.h> |
| #include <net/if_arp.h> |
| #include <sys/ioctl.h> |
| |
| #include <asm/types.h> |
| #include <linux/netlink.h> |
| #include <linux/rtnetlink.h> |
| |
| #include <not-cancel.h> |
| |
| #include "netlinkaccess.h" |
| |
| void |
| __check_native (uint32_t a1_index, int *a1_native, |
| uint32_t a2_index, int *a2_native) |
| { |
| int fd = __socket (PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE); |
| |
| struct sockaddr_nl nladdr; |
| memset (&nladdr, '\0', sizeof (nladdr)); |
| nladdr.nl_family = AF_NETLINK; |
| |
| socklen_t addr_len = sizeof (nladdr); |
| |
| if (fd < 0 |
| || __bind (fd, (struct sockaddr *) &nladdr, sizeof (nladdr)) != 0 |
| || __getsockname (fd, (struct sockaddr *) &nladdr, &addr_len) != 0) |
| return; |
| |
| pid_t pid = nladdr.nl_pid; |
| struct req |
| { |
| struct nlmsghdr nlh; |
| struct rtgenmsg g; |
| /* struct rtgenmsg consists of a single byte. This means there |
| are three bytes of padding included in the REQ definition. |
| We make them explicit here. */ |
| char pad[3]; |
| } req; |
| |
| req.nlh.nlmsg_len = sizeof (req); |
| req.nlh.nlmsg_type = RTM_GETLINK; |
| req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST; |
| req.nlh.nlmsg_pid = 0; |
| req.nlh.nlmsg_seq = time (NULL); |
| req.g.rtgen_family = AF_UNSPEC; |
| |
| assert (sizeof (req) - offsetof (struct req, pad) == 3); |
| memset (req.pad, '\0', sizeof (req.pad)); |
| |
| memset (&nladdr, '\0', sizeof (nladdr)); |
| nladdr.nl_family = AF_NETLINK; |
| |
| #ifdef PAGE_SIZE |
| /* Help the compiler optimize out the malloc call if PAGE_SIZE |
| is constant and smaller or equal to PTHREAD_STACK_MIN/4. */ |
| const size_t buf_size = PAGE_SIZE; |
| #else |
| const size_t buf_size = __getpagesize (); |
| #endif |
| bool use_malloc = false; |
| char *buf; |
| |
| if (__libc_use_alloca (buf_size)) |
| buf = alloca (buf_size); |
| else |
| { |
| buf = malloc (buf_size); |
| if (buf != NULL) |
| use_malloc = true; |
| else |
| goto out_fail; |
| } |
| |
| struct iovec iov = { buf, buf_size }; |
| |
| if (TEMP_FAILURE_RETRY (__sendto (fd, (void *) &req, sizeof (req), 0, |
| (struct sockaddr *) &nladdr, |
| sizeof (nladdr))) < 0) |
| goto out_fail; |
| |
| bool done = false; |
| do |
| { |
| struct msghdr msg = |
| { |
| .msg_name = (void *) &nladdr, |
| .msg_namelen = sizeof (nladdr), |
| .msg_iov = &iov, |
| .msg_iovlen = 1, |
| .msg_control = NULL, |
| .msg_controllen = 0, |
| .msg_flags = 0 |
| }; |
| |
| ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0)); |
| __netlink_assert_response (fd, read_len); |
| if (read_len < 0) |
| goto out_fail; |
| |
| if (msg.msg_flags & MSG_TRUNC) |
| goto out_fail; |
| |
| struct nlmsghdr *nlmh; |
| for (nlmh = (struct nlmsghdr *) buf; |
| NLMSG_OK (nlmh, (size_t) read_len); |
| nlmh = (struct nlmsghdr *) NLMSG_NEXT (nlmh, read_len)) |
| { |
| if (nladdr.nl_pid != 0 || (pid_t) nlmh->nlmsg_pid != pid |
| || nlmh->nlmsg_seq != req.nlh.nlmsg_seq) |
| continue; |
| |
| if (nlmh->nlmsg_type == RTM_NEWLINK) |
| { |
| struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlmh); |
| int native = (ifim->ifi_type != ARPHRD_TUNNEL6 |
| && ifim->ifi_type != ARPHRD_TUNNEL |
| && ifim->ifi_type != ARPHRD_SIT); |
| |
| if (a1_index == ifim->ifi_index) |
| { |
| *a1_native = native; |
| a1_index = 0xffffffffu; |
| } |
| if (a2_index == ifim->ifi_index) |
| { |
| *a2_native = native; |
| a2_index = 0xffffffffu; |
| } |
| |
| if (a1_index == 0xffffffffu |
| && a2_index == 0xffffffffu) |
| goto out; |
| } |
| else if (nlmh->nlmsg_type == NLMSG_DONE) |
| /* We found the end, leave the loop. */ |
| done = true; |
| } |
| } |
| while (! done); |
| |
| out: |
| __close_nocancel_nostatus (fd); |
| |
| return; |
| |
| out_fail: |
| if (use_malloc) |
| free (buf); |
| } |