diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/check_native.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/check_native.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/check_native.c b/sysdeps/unix/sysv/linux/check_native.c new file mode 100644 index 0000000000..6e6624abe1 --- /dev/null +++ b/sysdeps/unix/sysv/linux/check_native.c @@ -0,0 +1,172 @@ +/* Determine whether interfaces use native transport. Linux version. + Copyright (C) 2007 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <assert.h> +#include <errno.h> +#include <ifaddrs.h> +#include <stddef.h> +#include <stdint.h> +#include <stdlib.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> + + +void +__check_native (uint32_t a1_index, int *a1_native, + uint32_t a2_index, int *a2_native) +{ + int fd = __socket (PF_NETLINK, SOCK_RAW, 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 = + { + (void *) &nladdr, sizeof (nladdr), + &iov, 1, + NULL, 0, + 0 + }; + + ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0)); + 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_not_cancel_no_status (fd); + + return; + +out_fail: + if (use_malloc) + free (buf); +} |