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glibc  2.9
Defines | Functions | Variables
check_pf.c File Reference
#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 <sys/socket.h>
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <not-cancel.h>
#include <kernel-features.h>
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Defines

#define IFA_F_HOMEADDRESS   0
#define IFA_F_OPTIMISTIC   0

Functions

static int make_request (int fd, pid_t pid, bool *seen_ipv4, bool *seen_ipv6, struct in6addrinfo **in6ai, size_t *in6ailen)
void attribute_hidden __check_pf (bool *seen_ipv4, bool *seen_ipv6, struct in6addrinfo **in6ai, size_t *in6ailen)

Variables

int __no_netlink_support attribute_hidden

Define Documentation

#define IFA_F_HOMEADDRESS   0

Definition at line 39 of file check_pf.c.

#define IFA_F_OPTIMISTIC   0

Definition at line 42 of file check_pf.c.


Function Documentation

void attribute_hidden __check_pf ( bool *  seen_ipv4,
bool *  seen_ipv6,
struct in6addrinfo **  in6ai,
size_t in6ailen 
)

Definition at line 255 of file check_pf.c.

{
  *in6ai = NULL;
  *in6ailen = 0;

  if (! __no_netlink_support)
    {
      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
         && make_request (fd, nladdr.nl_pid, seen_ipv4, seen_ipv6,
                        in6ai, in6ailen) == 0)
       /* It worked.  */
       return;

      if (fd >= 0)
       __close (fd);

#if __ASSUME_NETLINK_SUPPORT == 0
      /* Remember that there is no netlink support.  */
      __no_netlink_support = 1;
#else
      /* We cannot determine what interfaces are available.  Be
        pessimistic.  */
      *seen_ipv4 = true;
      *seen_ipv6 = true;
#endif
    }

#if __ASSUME_NETLINK_SUPPORT == 0
  /* No netlink.  Get the interface list via getifaddrs.  */
  struct ifaddrs *ifa = NULL;
  if (getifaddrs (&ifa) != 0)
    {
      /* We cannot determine what interfaces are available.  Be
        pessimistic.  */
      *seen_ipv4 = true;
      *seen_ipv6 = true;
      return;
    }

  struct ifaddrs *runp;
  for (runp = ifa; runp != NULL; runp = runp->ifa_next)
    if (runp->ifa_addr->sa_family == PF_INET)
      *seen_ipv4 = true;
    else if (runp->ifa_addr->sa_family == PF_INET6)
      *seen_ipv6 = true;

  (void) freeifaddrs (ifa);
#endif
}

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static int make_request ( int  fd,
pid_t  pid,
bool *  seen_ipv4,
bool *  seen_ipv6,
struct in6addrinfo **  in6ai,
size_t in6ailen 
) [static]

Definition at line 47 of file check_pf.c.

{
  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
  /* 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;

  *seen_ipv4 = false;
  *seen_ipv6 = false;

  bool done = false;
  struct in6ailist
  {
    struct in6addrinfo info;
    struct in6ailist *next;
  } *in6ailist = NULL;
  size_t in6ailistlen = 0;

  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_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;
                  }
              }

             struct in6ailist *newp = alloca (sizeof (*newp));
             newp->info.flags = (((ifam->ifa_flags
                                & (IFA_F_DEPRECATED
                                   | IFA_F_OPTIMISTIC))
                               ? in6ai_deprecated : 0)
                              | ((ifam->ifa_flags
                                  & IFA_F_HOMEADDRESS)
                                 ? in6ai_homeaddress : 0));
             newp->info.prefixlen = ifam->ifa_prefixlen;
             newp->info.index = ifam->ifa_index;
             if (ifam->ifa_family == AF_INET)
              {
                newp->info.addr[0] = 0;
                newp->info.addr[1] = 0;
                newp->info.addr[2] = htonl (0xffff);
                newp->info.addr[3] = *(const in_addr_t *) address;
              }
             else
              memcpy (newp->info.addr, address, sizeof (newp->info.addr));
             newp->next = in6ailist;
             in6ailist = newp;
             ++in6ailistlen;
           }
         else if (nlmh->nlmsg_type == NLMSG_DONE)
           /* We found the end, leave the loop.  */
           done = true;
       }
    }
  while (! done);

  close_not_cancel_no_status (fd);

  if (*seen_ipv6 && in6ailist != NULL)
    {
      *in6ai = malloc (in6ailistlen * sizeof (**in6ai));
      if (*in6ai == NULL)
       goto out_fail;

      *in6ailen = in6ailistlen;

      do
       {
         (*in6ai)[--in6ailistlen] = in6ailist->info;
         in6ailist = in6ailist->next;
       }
      while (in6ailist != NULL);
    }

  if (use_malloc)
    free (buf);
  return 0;

out_fail:
  if (use_malloc)
    free (buf);
  return -1;
}

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Variable Documentation

int __no_netlink_support attribute_hidden

Definition at line 25 of file init-first.c.