1/*	$NetBSD: net.c,v 1.36 2019/03/31 20:08:45 christos 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#endif
68
69#include "net.h"
70
71/*
72 * Send a packet and wait for a reply, with exponential backoff.
73 *
74 * The send routine must return the actual number of bytes written,
75 * or -1 on error.
76 *
77 * The receive routine can indicate success by returning the number of
78 * bytes read; it can return 0 to indicate EOF; it can return -1 with a
79 * non-zero errno to indicate failure; finally, it can return -1 with a
80 * zero errno to indicate it isn't done yet.
81 */
82ssize_t
83sendrecv(struct iodesc *d,
84	ssize_t (*sproc)(struct iodesc *, void *, size_t),
85	void *sbuf, size_t ssize,
86	ssize_t (*rproc)(struct iodesc *, void *, size_t, saseconds_t),
87	void *rbuf, size_t rsize)
88{
89	ssize_t cc;
90	satime_t t, tlast;
91	saseconds_t tmo, tleft;
92
93#ifdef NET_DEBUG
94	if (debug)
95		printf("%s: called\n", __func__);
96#endif
97
98	tmo = MINTMO;
99	tlast = 0;
100	tleft = 0;
101	t = getsecs();
102	for (;;) {
103		if (tleft <= 0) {
104			if (tmo >= MAXTMO) {
105				errno = ETIMEDOUT;
106				return -1;
107			}
108			cc = (*sproc)(d, sbuf, ssize);
109
110			tleft = tmo;
111			tmo <<= 1;
112			if (tmo > MAXTMO)
113				tmo = MAXTMO;
114
115			if (cc == -1) {
116				/* Error on transmit; wait before retrying */
117				while ((getsecs() - t) < tmo)
118					delay();
119				tleft = 0;
120				continue;
121			}
122			if ((size_t)cc < ssize)
123				panic("%s: short write! (%zd < %zu)", __func__,
124				    cc, ssize);
125
126			tlast = t;
127		}
128
129		/* Try to get a packet and process it. */
130		cc = (*rproc)(d, rbuf, rsize, tleft);
131		/* Return on data, EOF or real error. */
132		if (cc != -1 || errno != 0)
133			return cc;
134
135		/* Timed out or didn't get the packet we're waiting for */
136		t = getsecs();
137		tleft -= t - tlast;
138		tlast = t;
139	}
140}
141