sys/lib/libsa/net.c

   1 /*      $NetBSD: net.c,v 1.35 2009/04/11 10:57:55 lukem Exp $   */
   2
   3 /*
   4  * Copyright (c) 1992 Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * This software was developed by the Computer Systems Engineering group
   8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   9  * contributed to Berkeley.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the University of
  22  *      California, Lawrence Berkeley Laboratory and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  * @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp  (LBL)
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/socket.h>
  44
  45 #ifdef _STANDALONE
  46 #include <lib/libkern/libkern.h>
  47 #else
  48 #include <string.h>
  49 #endif
  50
  51 #include <net/if.h>
  52 #include <net/if_ether.h>
  53
  54 #include <netinet/in.h>
  55 #include <netinet/in_systm.h>
  56 #include <netinet/ip.h>
  57
  58 #ifdef _STANDALONE
  59 #include "stand.h"
  60 #define delay()
  61 #else
  62 #include <errno.h>
  63 #include <stdio.h>
  64 #include <unistd.h>
  65 #define panic printf
  66 #define delay() usleep(100000)
  67 #define getsecs() time(NULL)
  68 #endif
  69
  70 #include "net.h"
  71
  72 /*
  73  * Send a packet and wait for a reply, with exponential backoff.
  74  *
  75  * The send routine must return the actual number of bytes written,
  76  * or -1 on error.
  77  *
  78  * The receive routine can indicate success by returning the number of
  79  * bytes read; it can return 0 to indicate EOF; it can return -1 with a
  80  * non-zero errno to indicate failure; finally, it can return -1 with a
  81  * zero errno to indicate it isn't done yet.
  82  */
  83 ssize_t
  84 sendrecv(struct iodesc *d,
  85         ssize_t (*sproc)(struct iodesc *, void *, size_t),
  86         void *sbuf, size_t ssize,
  87         ssize_t (*rproc)(struct iodesc *, void *, size_t, saseconds_t),
  88         void *rbuf, size_t rsize)
  89 {
  90         ssize_t cc;
  91         satime_t t, tlast;
  92         saseconds_t tmo, tleft;
  93
  94 #ifdef NET_DEBUG
  95         if (debug)
  96                 printf("sendrecv: called\n");
  97 #endif
  98
  99         tmo = MINTMO;
 100         tlast = 0;
 101         tleft = 0;
 102         t = getsecs();
 103         for (;;) {
 104                 if (tleft <= 0) {
 105                         if (tmo >= MAXTMO) {
 106                                 errno = ETIMEDOUT;
 107                                 return -1;
 108                         }
 109                         cc = (*sproc)(d, sbuf, ssize);
 110
 111                         tleft = tmo;
 112                         tmo <<= 1;
 113                         if (tmo > MAXTMO)
 114                                 tmo = MAXTMO;
 115
 116                         if (cc == -1) {
 117                                 /* Error on transmit; wait before retrying */
 118                                 while ((getsecs() - t) < tmo)
 119                                         delay();
 120                                 tleft = 0;
 121                                 continue;
 122                         }
 123                         if ((size_t)cc < ssize)
 124                                 panic("sendrecv: short write! (%zd < %zu)",
 125                                     cc, ssize);
 126
 127                         tlast = t;
 128                 }
 129
 130                 /* Try to get a packet and process it. */
 131                 cc = (*rproc)(d, rbuf, rsize, tleft);
 132                 /* Return on data, EOF or real error. */
 133                 if (cc != -1 || errno != 0)
 134                         return cc;
 135
 136                 /* Timed out or didn't get the packet we're waiting for */
 137                 t = getsecs();
 138                 tleft -= t - tlast;
 139                 tlast = t;
 140         }
 141 }