lib/sockets.c

   1 /* sockets.c. Rewriten by Andi Kleen. Subject to the GPL. */
   2
   3 /* philb 14/11/98: we now stash the socket file descriptor inside
   4    the `aftype' structure rather than keeping it in a pile of separate
   5    variables.  This is necessary so that "ifconfig eth0 broadcast ..."
   6    issues ioctls to the right socket for the address family in use;
   7    picking one at random doesn't always work.  */
   8
   9 #include <sys/socket.h>
  10 #include <stdio.h>
  11 #include <unistd.h>
  12
  13 #include "config.h"
  14 #include "sockets.h"
  15 #include "intl.h"
  16 #include "util.h"
  17 #include "net-support.h"
  18
  19 int skfd = -1;                  /* generic raw socket desc.     */
  20
  21 int sockets_open(int family)
  22 {
  23     struct aftype **aft;
  24     int sfd = -1;
  25     static int force = -1;
  26
  27     if (force < 0) {
  28         force = 0;
  29         if (kernel_version() < KRELEASE(2, 1, 0))
  30             force = 1;
  31         if (access("/proc/net", R_OK))
  32             force = 1;
  33     }
  34     for (aft = aftypes; *aft; aft++) {
  35         struct aftype *af = *aft;
  36         int type = SOCK_DGRAM;
  37         if (af->af == AF_UNSPEC)
  38             continue;
  39         if (family && family != af->af)
  40             continue;
  41         if (af->fd != -1) {
  42             sfd = af->fd;
  43             continue;
  44         }
  45         /* Check some /proc file first to not stress kmod */
  46         if (!family && !force && af->flag_file) {
  47             if (access(af->flag_file, R_OK))
  48                 continue;
  49         }
  50 #if HAVE_AFNETROM
  51         if (af->af == AF_NETROM)
  52             type = SOCK_SEQPACKET;
  53 #endif
  54 #if HAVE_AFX25
  55        if (af->af == AF_X25)
  56            type = SOCK_SEQPACKET;
  57 #endif
  58         af->fd = socket(af->af, type, 0);
  59         if (af->fd >= 0)
  60             sfd = af->fd;
  61     }
  62     if (sfd < 0)
  63         fprintf(stderr, _("No usable address families found.\n"));
  64     return sfd;
  65 }