1/*	$NetBSD: net.c,v 1.34 2009/01/31 06:22:46 isaki 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#define getsecs() time(NULL)
68#endif
69
70#include "net.h"
71
72/*
73 * Send a packet and wait for a reply, with exponential backoff.
74 *
75 * The send routine must return the actual number of bytes written,
76 * or -1 on error.
77 *
78 * The receive routine can indicate success by returning the number of
79 * bytes read; it can return 0 to indicate EOF; it can return -1 with a
80 * non-zero errno to indicate failure; finally, it can return -1 with a
81 * zero errno to indicate it isn't done yet.
82 */
83ssize_t
84sendrecv(struct iodesc *d,
85	ssize_t (*sproc)(struct iodesc *, void *, size_t),
86	void *sbuf, size_t ssize,
87	ssize_t (*rproc)(struct iodesc *, void *, size_t, saseconds_t),
88	void *rbuf, size_t rsize)
89{
90	ssize_t cc;
91	satime_t t, tlast;
92	saseconds_t tmo, tleft;
93
94#ifdef NET_DEBUG
95	if (debug)
96		printf("sendrecv: called\n");
97#endif
98
99	tmo = MINTMO;
100	tlast = 0;
101	tleft = 0;
102	t = getsecs();
103	for (;;) {
104		if (tleft <= 0) {
105			if (tmo >= MAXTMO) {
106				errno = ETIMEDOUT;
107				return -1;
108			}
109			cc = (*sproc)(d, sbuf, ssize);
110
111			tleft = tmo;
112			tmo <<= 1;
113			if (tmo > MAXTMO)
114				tmo = MAXTMO;
115
116			if (cc == -1) {
117				/* Error on transmit; wait before retrying */
118				while ((getsecs() - t) < tmo)
119					delay();
120				tleft = 0;
121				continue;
122			}
123			if ((size_t)cc < ssize)
124				panic("sendrecv: short write! (%zd < %zu)",
125				    cc, ssize);
126
127			tlast = t;
128		}
129
130		/* Try to get a packet and process it. */
131		cc = (*rproc)(d, rbuf, rsize, tleft);
132		/* Return on data, EOF or real error. */
133		if (cc != -1 || errno != 0)
134			return cc;
135
136		/* Timed out or didn't get the packet we're waiting for */
137		t = getsecs();
138		tleft -= t - tlast;
139		tlast = t;
140	}
141}
142