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 * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL)
36 */
37
38 #include <sys/cdefs.h>
39
40 #include <sys/param.h>
41 #include <sys/socket.h>
42 #include <net/if.h>
43 #include <netinet/in.h>
44 #include <netinet/if_ether.h>
45
46 #include <netinet/in_systm.h>
47
48 #include <string.h>
49
50 #include "stand.h"
51 #include "net.h"
52 #include "netif.h"
53
54
55 static ssize_t rarpsend(struct iodesc *, void *, size_t);
56 static ssize_t rarprecv(struct iodesc *, void **, void **, time_t, void *);
57
58 /*
59 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
60 */
61 int
rarp_getipaddress(int sock)62 rarp_getipaddress(int sock)
63 {
64 struct iodesc *d;
65 struct ether_arp *ap;
66 void *pkt;
67 struct {
68 u_char header[ETHER_SIZE];
69 struct {
70 struct ether_arp arp;
71 u_char pad[18]; /* 60 - sizeof(arp) */
72 } data;
73 } wbuf;
74
75 #ifdef RARP_DEBUG
76 if (debug)
77 printf("rarp: socket=%d\n", sock);
78 #endif
79 if (!(d = socktodesc(sock))) {
80 printf("rarp: bad socket. %d\n", sock);
81 return (-1);
82 }
83 #ifdef RARP_DEBUG
84 if (debug)
85 printf("rarp: d=%x\n", (u_int)d);
86 #endif
87
88 bzero((char*)&wbuf.data, sizeof(wbuf.data));
89 ap = &wbuf.data.arp;
90 ap->arp_hrd = htons(ARPHRD_ETHER);
91 ap->arp_pro = htons(ETHERTYPE_IP);
92 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
93 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
94 ap->arp_op = htons(ARPOP_REVREQUEST);
95 bcopy(d->myea, ap->arp_sha, 6);
96 bcopy(d->myea, ap->arp_tha, 6);
97 pkt = NULL;
98
99 if (sendrecv(d,
100 rarpsend, &wbuf.data, sizeof(wbuf.data),
101 rarprecv, &pkt, (void *)&ap, NULL) < 0) {
102 printf("No response for RARP request\n");
103 return (-1);
104 }
105
106 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip));
107 #if 0
108 /* XXX - Can NOT assume this is our root server! */
109 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip));
110 #endif
111 free(pkt);
112
113 /* Compute our "natural" netmask. */
114 if (IN_CLASSA(myip.s_addr))
115 netmask = IN_CLASSA_NET;
116 else if (IN_CLASSB(myip.s_addr))
117 netmask = IN_CLASSB_NET;
118 else
119 netmask = IN_CLASSC_NET;
120
121 d->myip = myip;
122 return (0);
123 }
124
125 /*
126 * Broadcast a RARP request (i.e. who knows who I am)
127 */
128 static ssize_t
rarpsend(struct iodesc * d,void * pkt,size_t len)129 rarpsend(struct iodesc *d, void *pkt, size_t len)
130 {
131
132 #ifdef RARP_DEBUG
133 if (debug)
134 printf("rarpsend: called\n");
135 #endif
136
137 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP));
138 }
139
140 /*
141 * Returns 0 if this is the packet we're waiting for
142 * else -1 (and errno == 0)
143 */
144 static ssize_t
rarprecv(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,void * extra __unused)145 rarprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft,
146 void *extra __unused)
147 {
148 ssize_t n;
149 struct ether_arp *ap;
150 void *ptr = NULL;
151 uint16_t etype; /* host order */
152
153 #ifdef RARP_DEBUG
154 if (debug)
155 printf("rarprecv: ");
156 #endif
157
158 n = readether(d, &ptr, (void **)&ap, tleft, &etype);
159 errno = 0; /* XXX */
160 if (n == -1 || n < sizeof(struct ether_arp)) {
161 #ifdef RARP_DEBUG
162 if (debug)
163 printf("bad len=%d\n", n);
164 #endif
165 free(ptr);
166 return (-1);
167 }
168
169 if (etype != ETHERTYPE_REVARP) {
170 #ifdef RARP_DEBUG
171 if (debug)
172 printf("bad type=0x%x\n", etype);
173 #endif
174 free(ptr);
175 return (-1);
176 }
177
178 if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
179 ap->arp_pro != htons(ETHERTYPE_IP) ||
180 ap->arp_hln != sizeof(ap->arp_sha) ||
181 ap->arp_pln != sizeof(ap->arp_spa) )
182 {
183 #ifdef RARP_DEBUG
184 if (debug)
185 printf("bad hrd/pro/hln/pln\n");
186 #endif
187 free(ptr);
188 return (-1);
189 }
190
191 if (ap->arp_op != htons(ARPOP_REVREPLY)) {
192 #ifdef RARP_DEBUG
193 if (debug)
194 printf("bad op=0x%x\n", ntohs(ap->arp_op));
195 #endif
196 free(ptr);
197 return (-1);
198 }
199
200 /* Is the reply for our Ethernet address? */
201 if (bcmp(ap->arp_tha, d->myea, 6)) {
202 #ifdef RARP_DEBUG
203 if (debug)
204 printf("unwanted address\n");
205 #endif
206 free(ptr);
207 return (-1);
208 }
209
210 /* We have our answer. */
211 #ifdef RARP_DEBUG
212 if (debug)
213 printf("got it\n");
214 #endif
215 *pkt = ptr;
216 *payload = ap;
217 return (n);
218 }
219