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