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  */
82 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)83 sendrecv(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