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Diffstat (limited to 'REORG.TODO/sysdeps/unix/sysv/linux/check_pf.c')
-rw-r--r--REORG.TODO/sysdeps/unix/sysv/linux/check_pf.c391
1 files changed, 391 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/check_pf.c b/REORG.TODO/sysdeps/unix/sysv/linux/check_pf.c
new file mode 100644
index 0000000000..3bf221a177
--- /dev/null
+++ b/REORG.TODO/sysdeps/unix/sysv/linux/check_pf.c
@@ -0,0 +1,391 @@
+/* Determine protocol families for which interfaces exist. Linux version.
+ Copyright (C) 2003-2017 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 <netdb.h>
+#include <stddef.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <sys/socket.h>
+
+#include <asm/types.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <not-cancel.h>
+#include <libc-lock.h>
+#include <atomic.h>
+#include <nscd/nscd-client.h>
+
+#include "netlinkaccess.h"
+
+#ifndef IFA_F_HOMEADDRESS
+# define IFA_F_HOMEADDRESS 0
+#endif
+#ifndef IFA_F_OPTIMISTIC
+# define IFA_F_OPTIMISTIC 0
+#endif
+
+
+struct cached_data
+{
+ uint32_t timestamp;
+ uint32_t usecnt;
+ bool seen_ipv4;
+ bool seen_ipv6;
+ size_t in6ailen;
+ struct in6addrinfo in6ai[0];
+};
+
+static struct cached_data noai6ai_cached =
+ {
+ .usecnt = 1, /* Make sure we never try to delete this entry. */
+ .in6ailen = 0
+ };
+
+static struct cached_data *cache;
+__libc_lock_define_initialized (static, lock);
+
+
+#if IS_IN (nscd)
+static uint32_t nl_timestamp;
+
+uint32_t
+__bump_nl_timestamp (void)
+{
+ if (atomic_increment_val (&nl_timestamp) == 0)
+ atomic_increment (&nl_timestamp);
+
+ return nl_timestamp;
+}
+#endif
+
+static inline uint32_t
+get_nl_timestamp (void)
+{
+#if IS_IN (nscd)
+ return nl_timestamp;
+#elif defined USE_NSCD
+ return __nscd_get_nl_timestamp ();
+#else
+ return 0;
+#endif
+}
+
+static inline bool
+cache_valid_p (void)
+{
+ if (cache != NULL)
+ {
+ uint32_t timestamp = get_nl_timestamp ();
+ return timestamp != 0 && cache->timestamp == timestamp;
+ }
+ return false;
+}
+
+
+static struct cached_data *
+make_request (int fd, pid_t pid)
+{
+ struct cached_data *result = NULL;
+
+ size_t result_len = 0;
+ size_t result_cap = 32;
+
+ 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;
+ struct sockaddr_nl nladdr;
+
+ req.nlh.nlmsg_len = sizeof (req);
+ req.nlh.nlmsg_type = RTM_GETADDR;
+ 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
+ const size_t buf_size = PAGE_SIZE;
+#else
+ const size_t buf_size = 4096;
+#endif
+ char buf[buf_size];
+
+ 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;
+
+ bool seen_ipv4 = false;
+ bool seen_ipv6 = 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_NEWADDR)
+ {
+ struct ifaddrmsg *ifam = (struct ifaddrmsg *) NLMSG_DATA (nlmh);
+ struct rtattr *rta = IFA_RTA (ifam);
+ size_t len = nlmh->nlmsg_len - NLMSG_LENGTH (sizeof (*ifam));
+
+ if (ifam->ifa_family != AF_INET
+ && ifam->ifa_family != AF_INET6)
+ continue;
+
+ const void *local = NULL;
+ const void *address = NULL;
+ while (RTA_OK (rta, len))
+ {
+ switch (rta->rta_type)
+ {
+ case IFA_LOCAL:
+ local = RTA_DATA (rta);
+ break;
+
+ case IFA_ADDRESS:
+ address = RTA_DATA (rta);
+ goto out;
+ }
+
+ rta = RTA_NEXT (rta, len);
+ }
+
+ if (local != NULL)
+ {
+ address = local;
+ out:
+ if (ifam->ifa_family == AF_INET)
+ {
+ if (*(const in_addr_t *) address
+ != htonl (INADDR_LOOPBACK))
+ seen_ipv4 = true;
+ }
+ else
+ {
+ if (!IN6_IS_ADDR_LOOPBACK (address))
+ seen_ipv6 = true;
+ }
+ }
+
+ if (result_len == 0 || result_len == result_cap)
+ {
+ result_cap = 2 * result_cap;
+ result = realloc (result, sizeof (*result)
+ + result_cap
+ * sizeof (struct in6addrinfo));
+ }
+
+ if (!result)
+ goto out_fail;
+
+ struct in6addrinfo *info = &result->in6ai[result_len++];
+
+ info->flags = (((ifam->ifa_flags
+ & (IFA_F_DEPRECATED | IFA_F_OPTIMISTIC))
+ ? in6ai_deprecated : 0)
+ | ((ifam->ifa_flags & IFA_F_HOMEADDRESS)
+ ? in6ai_homeaddress : 0));
+ info->prefixlen = ifam->ifa_prefixlen;
+ info->index = ifam->ifa_index;
+ if (ifam->ifa_family == AF_INET)
+ {
+ info->addr[0] = 0;
+ info->addr[1] = 0;
+ info->addr[2] = htonl (0xffff);
+ info->addr[3] = *(const in_addr_t *) address;
+ }
+ else
+ memcpy (info->addr, address, sizeof (info->addr));
+ }
+ else if (nlmh->nlmsg_type == NLMSG_DONE)
+ /* We found the end, leave the loop. */
+ done = true;
+ }
+ }
+ while (! done);
+
+ if (seen_ipv6 && result != NULL)
+ {
+ result->timestamp = get_nl_timestamp ();
+ result->usecnt = 2;
+ result->seen_ipv4 = seen_ipv4;
+ result->seen_ipv6 = true;
+ result->in6ailen = result_len;
+ }
+ else
+ {
+ free (result);
+
+ atomic_add (&noai6ai_cached.usecnt, 2);
+ noai6ai_cached.seen_ipv4 = seen_ipv4;
+ noai6ai_cached.seen_ipv6 = seen_ipv6;
+ result = &noai6ai_cached;
+ }
+
+ return result;
+
+ out_fail:
+
+ free (result);
+ return NULL;
+}
+
+
+void
+attribute_hidden
+__check_pf (bool *seen_ipv4, bool *seen_ipv6,
+ struct in6addrinfo **in6ai, size_t *in6ailen)
+{
+ *in6ai = NULL;
+ *in6ailen = 0;
+
+ struct cached_data *olddata = NULL;
+ struct cached_data *data = NULL;
+
+ __libc_lock_lock (lock);
+
+ if (cache_valid_p ())
+ {
+ data = cache;
+ atomic_increment (&cache->usecnt);
+ }
+ else
+ {
+ int fd = __socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+
+ if (__glibc_likely (fd >= 0))
+ {
+ struct sockaddr_nl nladdr;
+ memset (&nladdr, '\0', sizeof (nladdr));
+ nladdr.nl_family = AF_NETLINK;
+
+ socklen_t addr_len = sizeof (nladdr);
+
+ if (__bind (fd, (struct sockaddr *) &nladdr, sizeof (nladdr)) == 0
+ && __getsockname (fd, (struct sockaddr *) &nladdr,
+ &addr_len) == 0)
+ data = make_request (fd, nladdr.nl_pid);
+
+ close_not_cancel_no_status (fd);
+ }
+
+ if (data != NULL)
+ {
+ olddata = cache;
+ cache = data;
+ }
+ }
+
+ __libc_lock_unlock (lock);
+
+ if (data != NULL)
+ {
+ /* It worked. */
+ *seen_ipv4 = data->seen_ipv4;
+ *seen_ipv6 = data->seen_ipv6;
+ *in6ailen = data->in6ailen;
+ *in6ai = data->in6ai;
+
+ if (olddata != NULL && olddata->usecnt > 0
+ && atomic_add_zero (&olddata->usecnt, -1))
+ free (olddata);
+
+ return;
+ }
+
+ /* We cannot determine what interfaces are available. Be
+ pessimistic. */
+ *seen_ipv4 = true;
+ *seen_ipv6 = true;
+}
+
+/* Free the cache if it has been allocated. */
+libc_freeres_fn (freecache)
+{
+ if (cache)
+ __free_in6ai (cache->in6ai);
+}
+
+void
+__free_in6ai (struct in6addrinfo *ai)
+{
+ if (ai != NULL)
+ {
+ struct cached_data *data =
+ (struct cached_data *) ((char *) ai
+ - offsetof (struct cached_data, in6ai));
+
+ if (atomic_add_zero (&data->usecnt, -1))
+ {
+ __libc_lock_lock (lock);
+
+ if (data->usecnt == 0)
+ /* Still unused. */
+ free (data);
+
+ __libc_lock_unlock (lock);
+ }
+ }
+}
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