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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| /*
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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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| 
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| #include <sys/param.h>
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| #include <sys/socket.h>
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| 
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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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| 
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| #include <net/if.h>
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| #include <net/if_ether.h>
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| 
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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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| 
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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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| 
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| #include "net.h"
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| 			tlast = t;
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| 		}
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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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| 
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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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