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glibc  2.9
Defines | Functions | Variables
if_index.c File Reference
#include <alloca.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <bits/libc-lock.h>
#include <not-cancel.h>
#include <kernel-features.h>
#include "netlinkaccess.h"

Go to the source code of this file.

Defines

#define RQ_IFS   4

Functions

unsigned int if_nametoindex (const char *ifname)
 libc_hidden_def (if_nametoindex)
 libc_hidden_def (if_freenameindex)
static struct if_nameindexif_nameindex_netlink (void)
struct if_nameindexif_nameindex (void)
 libc_hidden_def (if_nameindex)

Variables

static int old_siocgifconf

Define Documentation

#define RQ_IFS   4

Function Documentation

struct if_nameindex* if_nameindex ( void  ) [read]

Definition at line 298 of file if_index.c.

{
#ifndef SIOCGIFINDEX
  __set_errno (ENOSYS);
  return NULL;
#else
  struct if_nameindex *result = if_nameindex_netlink ();
# if __ASSUME_NETLINK_SUPPORT == 0
  if (__no_netlink_support)
    result = if_nameindex_ioctl ();
# endif
  return result;
#endif
}

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static struct if_nameindex* if_nameindex_netlink ( void  ) [static, read]

Definition at line 183 of file if_index.c.

{
  struct netlink_handle nh = { 0, 0, 0, NULL, NULL };
  struct if_nameindex *idx = NULL;

  if (__no_netlink_support || __netlink_open (&nh) < 0)
    return NULL;


  /* Tell the kernel that we wish to get a list of all
     active interfaces.  Collect all data for every interface.  */
  if (__netlink_request (&nh, RTM_GETLINK) < 0)
    goto exit_free;

  /* Count the interfaces.  */
  unsigned int nifs = 0;
  for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
    {
      struct nlmsghdr *nlh;
      size_t size = nlp->size;

      if (nlp->nlh == NULL)
       continue;

      /* Walk through all entries we got from the kernel and look, which
         message type they contain.  */
      for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
       {
         /* Check if the message is what we want.  */
         if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
           continue;

         if (nlh->nlmsg_type == NLMSG_DONE)
           break;           /* ok */

         if (nlh->nlmsg_type == RTM_NEWLINK)
           ++nifs;
       }
    }

  idx = malloc ((nifs + 1) * sizeof (struct if_nameindex));
  if (idx == NULL)
    {
    nomem:
      __set_errno (ENOBUFS);
      goto exit_free;
    }

  /* Add the interfaces.  */
  nifs = 0;
  for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
    {
      struct nlmsghdr *nlh;
      size_t size = nlp->size;

      if (nlp->nlh == NULL)
       continue;

      /* Walk through all entries we got from the kernel and look, which
         message type they contain.  */
      for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
       {
         /* Check if the message is what we want.  */
         if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
           continue;

         if (nlh->nlmsg_type == NLMSG_DONE)
           break;           /* ok */

         if (nlh->nlmsg_type == RTM_NEWLINK)
           {
             struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlh);
             struct rtattr *rta = IFLA_RTA (ifim);
             size_t rtasize = IFLA_PAYLOAD (nlh);

             idx[nifs].if_index = ifim->ifi_index;

             while (RTA_OK (rta, rtasize))
              {
                char *rta_data = RTA_DATA (rta);
                size_t rta_payload = RTA_PAYLOAD (rta);

                if (rta->rta_type == IFLA_IFNAME)
                  {
                    idx[nifs].if_name = __strndup (rta_data, rta_payload);
                    if (idx[nifs].if_name == NULL)
                     {
                       idx[nifs].if_index = 0;
                       if_freenameindex (idx);
                       idx = NULL;
                       goto nomem;
                     }
                    break;
                  }

                rta = RTA_NEXT (rta, rtasize);
              }

             ++nifs;
           }
       }
    }

  idx[nifs].if_index = 0;
  idx[nifs].if_name = NULL;

 exit_free:
  __netlink_free_handle (&nh);
  __netlink_close (&nh);

  return idx;
}

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unsigned int if_nametoindex ( const char *  ifname)

Definition at line 45 of file if_index.c.

{
#ifndef SIOCGIFINDEX
  __set_errno (ENOSYS);
  return 0;
#else
  struct ifreq ifr;
  int fd = __opensock ();

  if (fd < 0)
    return 0;

  strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
  if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)
    {
      int saved_errno = errno;
      close_not_cancel_no_status (fd);
      if (saved_errno == EINVAL)
       __set_errno (ENOSYS);
      return 0;
    }
  close_not_cancel_no_status (fd);
  return ifr.ifr_ifindex;
#endif
}

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Definition at line 70 of file if_index.c.

{
  struct if_nameindex *ptr = ifn;
  while (ptr->if_name || ptr->if_index)
    {
      free (ptr->if_name);
      ++ptr;
    }
  free (ifn);
}

Definition at line 84 of file if_index.c.

{
  int fd = __opensock ();
  struct ifconf ifc;
  unsigned int nifs, i;
  int rq_len;
  struct if_nameindex *idx = NULL;
# define RQ_IFS      4

  if (fd < 0)
    return NULL;

  ifc.ifc_buf = NULL;

  /* We may be able to get the needed buffer size directly, rather than
     guessing.  */
  if (! old_siocgifconf)
    {
      ifc.ifc_buf = NULL;
      ifc.ifc_len = 0;
      if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0)
       {
# if __ASSUME_SIOCGIFNAME == 0
         old_siocgifconf = 1;
# endif
         rq_len = RQ_IFS * sizeof (struct ifreq);
       }
      else
       rq_len = ifc.ifc_len;
    }
  else
    rq_len = RQ_IFS * sizeof (struct ifreq);

  /* Read all the interfaces out of the kernel.  */
  ifc.ifc_buf = alloca (rq_len);
  ifc.ifc_len = rq_len;
  while (1)
    {
        if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0)
       {
         close_not_cancel_no_status (fd);
         return NULL;
       }
      if (ifc.ifc_len < rq_len || ! old_siocgifconf)
       break;

      ifc.ifc_buf = extend_alloca (ifc.ifc_buf, rq_len, 2 * rq_len);
      ifc.ifc_len = rq_len;
    }

  nifs = ifc.ifc_len / sizeof (struct ifreq);

  idx = malloc ((nifs + 1) * sizeof (struct if_nameindex));
  if (idx == NULL)
    {
      close_not_cancel_no_status (fd);
      __set_errno (ENOBUFS);
      return NULL;
    }

  for (i = 0; i < nifs; ++i)
    {
      struct ifreq *ifr = &ifc.ifc_req[i];
      idx[i].if_name = __strdup (ifr->ifr_name);
      if (idx[i].if_name == NULL
         || __ioctl (fd, SIOCGIFINDEX, ifr) < 0)
       {
         int saved_errno = errno;
         unsigned int j;

         for (j =  0; j < i; ++j)
           free (idx[j].if_name);
         free (idx);
         close_not_cancel_no_status (fd);
         if (saved_errno == EINVAL)
           saved_errno = ENOSYS;
         else if (saved_errno == ENOMEM)
           saved_errno = ENOBUFS;
         __set_errno (saved_errno);
         return NULL;
       }
      idx[i].if_index = ifr->ifr_ifindex;
    }

  idx[i].if_index = 0;
  idx[i].if_name = NULL;

  close_not_cancel_no_status (fd);
  return idx;
}

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Definition at line 312 of file if_index.c.

{
#if !defined SIOCGIFINDEX && __ASSUME_SIOCGIFNAME == 0
  __set_errno (ENOSYS);
  return NULL;
#else
# if __ASSUME_SIOCGIFNAME == 0
  struct if_nameindex *idx;
  struct if_nameindex *p;
  char *result = NULL;
# endif

# if defined SIOCGIFNAME || __ASSUME_SIOCGIFNAME > 0
  /* We may be able to do the conversion directly, rather than searching a
     list.  This ioctl is not present in kernels before version 2.1.50.  */
  struct ifreq ifr;
  int fd;
#  if __ASSUME_SIOCGIFNAME == 0
  static int siocgifname_works_not;

  if (!siocgifname_works_not)
#  endif
    {
#  if __ASSUME_SIOCGIFNAME == 0
      int serrno = errno;
#  endif
      int status;

      fd = __opensock ();

      if (fd < 0)
       return NULL;

      ifr.ifr_ifindex = ifindex;
      status = __ioctl (fd, SIOCGIFNAME, &ifr);

      close_not_cancel_no_status (fd);

      if (status  < 0)
       {
#  if __ASSUME_SIOCGIFNAME == 0
         if (errno == EINVAL)
           siocgifname_works_not = 1; /* Don't make the same mistake twice. */
         else
#  endif
           {
             if (errno == ENODEV)
              /* POSIX requires ENXIO.  */
              __set_errno (ENXIO);

             return NULL;
           }
       }
      else
       return strncpy (ifname, ifr.ifr_name, IFNAMSIZ);

#  if __ASSUME_SIOCGIFNAME == 0
      __set_errno (serrno);
#  endif
    }
# endif

# if __ASSUME_SIOCGIFNAME == 0
  idx = if_nameindex ();

  if (idx != NULL)
    {
      for (p = idx; p->if_index || p->if_name; ++p)
       if (p->if_index == ifindex)
         {
           result = strncpy (ifname, p->if_name, IFNAMSIZ);
           break;
         }

      if_freenameindex (idx);

      if (result == NULL)
       __set_errno (ENXIO);
    }
  return result;
# endif
#endif
}

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Variable Documentation

int old_siocgifconf [static]

Definition at line 38 of file if_index.c.