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net.c revision 1.23.2.2 
      1 /*	$NetBSD: net.c,v 1.23.2.2 2000/11/22 16:05:43 bouyer 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 #include "stand.h"
     59 #include "net.h"
     60 
     61 /*
     62  * Send a packet and wait for a reply, with exponential backoff.
     63  *
     64  * The send routine must return the actual number of bytes written,
     65  * or -1 on error.
     66  *
     67  * The receive routine can indicate success by returning the number of
     68  * bytes read; it can return 0 to indicate EOF; it can return -1 with a
     69  * non-zero errno to indicate failure; finally, it can return -1 with a
     70  * zero errno to indicate it isn't done yet.
     71  */
     72 ssize_t
     73 sendrecv(d, sproc, sbuf, ssize, rproc, rbuf, rsize)
     74 	struct iodesc *d;
     75 	ssize_t (*sproc)(struct iodesc *, void *, size_t);
     76 	void *sbuf;
     77 	size_t ssize;
     78 	ssize_t (*rproc)(struct iodesc *, void *, size_t, time_t);
     79 	void *rbuf;
     80 	size_t rsize;
     81 {
     82 	ssize_t cc;
     83 	time_t t, tmo, tlast;
     84 	long tleft;
     85 
     86 #ifdef NET_DEBUG
     87 	if (debug)
     88 		printf("sendrecv: called\n");
     89 #endif
     90 
     91 	tmo = MINTMO;
     92 	tlast = tleft = 0;
     93 	t = getsecs();
     94 	for (;;) {
     95 		if (tleft <= 0) {
     96 			if (tmo >= MAXTMO) {
     97 				errno = ETIMEDOUT;
     98 				return -1;
     99 			}
    100 			cc = (*sproc)(d, sbuf, ssize);
    101 			if (cc != -1 && cc < ssize)
    102 				panic("sendrecv: short write! (%d < %d)",
    103 				    cc, ssize);
    104 
    105 			tleft = tmo;
    106 			tmo <<= 1;
    107 			if (tmo > MAXTMO)
    108 				tmo = MAXTMO;
    109 
    110 			if (cc == -1) {
    111 				/* Error on transmit; wait before retrying */
    112 				while ((getsecs() - t) < tmo);
    113 				tleft = 0;
    114 				continue;
    115 			}
    116 
    117 			tlast = t;
    118 		}
    119 
    120 		/* Try to get a packet and process it. */
    121 		cc = (*rproc)(d, rbuf, rsize, tleft);
    122 		/* Return on data, EOF or real error. */
    123 		if (cc != -1 || errno != 0)
    124 			return (cc);
    125 
    126 		/* Timed out or didn't get the packet we're waiting for */
    127 		t = getsecs();
    128 		tleft -= t - tlast;
    129 		tlast = t;
    130 	}
    131 }
    132