sunrpc/bindrsvprt.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user.
   8  *
   9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  12  *
  13  * Sun RPC is provided with no support and without any obligation on the
  14  * part of Sun Microsystems, Inc. to assist in its use, correction,
  15  * modification or enhancement.
  16  *
  17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  19  * OR ANY PART THEREOF.
  20  *
  21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  22  * or profits or other special, indirect and consequential damages, even if
  23  * Sun has been advised of the possibility of such damages.
  24  *
  25  * Sun Microsystems, Inc.
  26  * 2550 Garcia Avenue
  27  * Mountain View, California  94043
  28  */
  29 /*
  30  * Copyright (c) 1987 by Sun Microsystems, Inc.
  31  */
  32
  33 #include <errno.h>
  34 #include <unistd.h>
  35 #include <string.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38 #include <netinet/in.h>
  39
  40 /*
  41  * Bind a socket to a privileged IP port
  42  */
  43 int
  44 bindresvport (int sd, struct sockaddr_in *sin)
  45 {
  46   static short port;
  47   struct sockaddr_in myaddr;
  48   int i;
  49
  50 #define STARTPORT 600
  51 #define LOWPORT 512
  52 #define ENDPORT (IPPORT_RESERVED - 1)
  53 #define NPORTS  (ENDPORT - STARTPORT + 1)
  54   static short startport = STARTPORT;
  55
  56   if (sin == (struct sockaddr_in *) 0)
  57     {
  58       sin = &myaddr;
  59       __bzero (sin, sizeof (*sin));
  60       sin->sin_family = AF_INET;
  61     }
  62   else if (sin->sin_family != AF_INET)
  63     {
  64       __set_errno (EAFNOSUPPORT);
  65       return -1;
  66     }
  67
  68   if (port == 0)
  69     {
  70       port = (__getpid () % NPORTS) + STARTPORT;
  71     }
  72
  73   /* Initialize to make gcc happy.  */
  74   int res = -1;
  75
  76   int nports = ENDPORT - startport + 1;
  77   int endport = ENDPORT;
  78  again:
  79   for (i = 0; i < nports; ++i)
  80     {
  81       sin->sin_port = htons (port++);
  82       if (port > endport)
  83         port = startport;
  84       res = __bind (sd, sin, sizeof (struct sockaddr_in));
  85       if (res >= 0 || errno != EADDRINUSE)
  86         break;
  87     }
  88
  89   if (i == nports && startport != LOWPORT)
  90     {
  91       startport = LOWPORT;
  92       endport = STARTPORT - 1;
  93       nports = STARTPORT - LOWPORT;
  94       port = LOWPORT + port % (STARTPORT - LOWPORT);
  95       goto again;
  96     }
  97
  98   return res;
  99 }
 100 libc_hidden_def (bindresvport)