1 /* $NetBSD: rarp.c,v 1.16 1997/07/07 15:52:52 drochner 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. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <sys/param.h>
37 #include <sys/socket.h>
38 #include <net/if.h>
39 #include <netinet/in.h>
40 #include <netinet/if_ether.h>
41
42 #include <netinet/in_systm.h>
43
44 #include <string.h>
45
46 #include "stand.h"
47 #include "net.h"
48 #include "netif.h"
49
50
51 static ssize_t rarpsend(struct iodesc *, void *, size_t);
52 static ssize_t rarprecv(struct iodesc *, void **, void **, time_t, void *);
53
54 /*
55 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
56 */
57 int
rarp_getipaddress(int sock)58 rarp_getipaddress(int sock)
59 {
60 struct iodesc *d;
61 struct ether_arp *ap;
62 void *pkt;
63 struct {
64 u_char header[ETHER_SIZE];
65 struct {
66 struct ether_arp arp;
67 u_char pad[18]; /* 60 - sizeof(arp) */
68 } data;
69 } wbuf;
70
71 #ifdef RARP_DEBUG
72 if (debug)
73 printf("rarp: socket=%d\n", sock);
74 #endif
75 if (!(d = socktodesc(sock))) {
76 printf("rarp: bad socket. %d\n", sock);
77 return (-1);
78 }
79 #ifdef RARP_DEBUG
80 if (debug)
81 printf("rarp: d=%lx\n", (long)d);
82 #endif
83
84 bzero((char*)&wbuf.data, sizeof(wbuf.data));
85 ap = &wbuf.data.arp;
86 ap->arp_hrd = htons(ARPHRD_ETHER);
87 ap->arp_pro = htons(ETHERTYPE_IP);
88 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
89 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
90 ap->arp_op = htons(ARPOP_REVREQUEST);
91 bcopy(d->myea, ap->arp_sha, 6);
92 bcopy(d->myea, ap->arp_tha, 6);
93 pkt = NULL;
94
95 if (sendrecv(d,
96 rarpsend, &wbuf.data, sizeof(wbuf.data),
97 rarprecv, &pkt, (void *)&ap, NULL) < 0) {
98 printf("No response for RARP request\n");
99 return (-1);
100 }
101
102 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip));
103 #if 0
104 /* XXX - Can NOT assume this is our root server! */
105 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip));
106 #endif
107 free(pkt);
108
109 /* Compute our "natural" netmask. */
110 if (IN_CLASSA(myip.s_addr))
111 netmask = IN_CLASSA_NET;
112 else if (IN_CLASSB(myip.s_addr))
113 netmask = IN_CLASSB_NET;
114 else
115 netmask = IN_CLASSC_NET;
116
117 d->myip = myip;
118 return (0);
119 }
120
121 /*
122 * Broadcast a RARP request (i.e. who knows who I am)
123 */
124 static ssize_t
rarpsend(struct iodesc * d,void * pkt,size_t len)125 rarpsend(struct iodesc *d, void *pkt, size_t len)
126 {
127
128 #ifdef RARP_DEBUG
129 if (debug)
130 printf("rarpsend: called\n");
131 #endif
132
133 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP));
134 }
135
136 /*
137 * Returns 0 if this is the packet we're waiting for
138 * else -1 (and errno == 0)
139 */
140 static ssize_t
rarprecv(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,void * extra)141 rarprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft,
142 void *extra)
143 {
144 ssize_t n;
145 struct ether_arp *ap;
146 void *ptr = NULL;
147 uint16_t etype; /* host order */
148
149 #ifdef RARP_DEBUG
150 if (debug)
151 printf("rarprecv: ");
152 #endif
153
154 n = readether(d, &ptr, (void **)&ap, tleft, &etype);
155 errno = 0; /* XXX */
156 if (n == -1 || n < sizeof(struct ether_arp)) {
157 #ifdef RARP_DEBUG
158 if (debug)
159 printf("bad len=%zd\n", n);
160 #endif
161 free(ptr);
162 return (-1);
163 }
164
165 if (etype != ETHERTYPE_REVARP) {
166 #ifdef RARP_DEBUG
167 if (debug)
168 printf("bad type=0x%x\n", etype);
169 #endif
170 free(ptr);
171 return (-1);
172 }
173
174 if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
175 ap->arp_pro != htons(ETHERTYPE_IP) ||
176 ap->arp_hln != sizeof(ap->arp_sha) ||
177 ap->arp_pln != sizeof(ap->arp_spa) )
178 {
179 #ifdef RARP_DEBUG
180 if (debug)
181 printf("bad hrd/pro/hln/pln\n");
182 #endif
183 free(ptr);
184 return (-1);
185 }
186
187 if (ap->arp_op != htons(ARPOP_REVREPLY)) {
188 #ifdef RARP_DEBUG
189 if (debug)
190 printf("bad op=0x%x\n", ntohs(ap->arp_op));
191 #endif
192 free(ptr);
193 return (-1);
194 }
195
196 /* Is the reply for our Ethernet address? */
197 if (bcmp(ap->arp_tha, d->myea, 6)) {
198 #ifdef RARP_DEBUG
199 if (debug)
200 printf("unwanted address\n");
201 #endif
202 free(ptr);
203 return (-1);
204 }
205
206 /* We have our answer. */
207 #ifdef RARP_DEBUG
208 if (debug)
209 printf("got it\n");
210 #endif
211 *pkt = ptr;
212 *payload = ap;
213 return (n);
214 }
215