142 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			142 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$NetBSD: net.c,v 1.35 2009/04/11 10:57:55 lukem Exp $	*/
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/*
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 * Copyright (c) 1992 Regents of the University of California.
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 * All rights reserved.
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 *
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 * This software was developed by the Computer Systems Engineering group
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 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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 * contributed to Berkeley.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *	This product includes software developed by the University of
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 *	California, Lawrence Berkeley Laboratory and its contributors.
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 * 4. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 *
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 * @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp  (LBL)
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 */
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#include <sys/param.h>
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#include <sys/socket.h>
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#ifdef _STANDALONE
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#include <lib/libkern/libkern.h>
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#else
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#include <string.h>
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#endif
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#include <net/if.h>
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#include <net/if_ether.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#ifdef _STANDALONE
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#include "stand.h"
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#define delay()
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#else
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#define panic printf
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#define delay() usleep(100000)
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#define getsecs() time(NULL)
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#endif
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#include "net.h"
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/*
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 * Send a packet and wait for a reply, with exponential backoff.
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 *
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 * The send routine must return the actual number of bytes written,
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 * or -1 on error.
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 *
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 * The receive routine can indicate success by returning the number of
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 * bytes read; it can return 0 to indicate EOF; it can return -1 with a
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 * non-zero errno to indicate failure; finally, it can return -1 with a
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 * zero errno to indicate it isn't done yet.
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 */
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ssize_t
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sendrecv(struct iodesc *d,
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	ssize_t (*sproc)(struct iodesc *, void *, size_t),
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	void *sbuf, size_t ssize,
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	ssize_t (*rproc)(struct iodesc *, void *, size_t, saseconds_t),
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	void *rbuf, size_t rsize)
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{
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	ssize_t cc;
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	satime_t t, tlast;
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	saseconds_t tmo, tleft;
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#ifdef NET_DEBUG
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	if (debug)
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		printf("sendrecv: called\n");
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#endif
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	tmo = MINTMO;
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	tlast = 0;
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	tleft = 0;
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	t = getsecs();
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	for (;;) {
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		if (tleft <= 0) {
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			if (tmo >= MAXTMO) {
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				errno = ETIMEDOUT;
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				return -1;
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			}
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			cc = (*sproc)(d, sbuf, ssize);
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			tleft = tmo;
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			tmo <<= 1;
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			if (tmo > MAXTMO)
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				tmo = MAXTMO;
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			if (cc == -1) {
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				/* Error on transmit; wait before retrying */
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				while ((getsecs() - t) < tmo)
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					delay();
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				tleft = 0;
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				continue;
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			}
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			if ((size_t)cc < ssize)
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				panic("sendrecv: short write! (%zd < %zu)",
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				    cc, ssize);
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			tlast = t;
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		}
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		/* Try to get a packet and process it. */
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		cc = (*rproc)(d, rbuf, rsize, tleft);
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		/* Return on data, EOF or real error. */
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		if (cc != -1 || errno != 0)
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			return cc;
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		/* Timed out or didn't get the packet we're waiting for */
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		t = getsecs();
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		tleft -= t - tlast;
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		tlast = t;
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	}
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}
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