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 __FBSDID("$FreeBSD$");
40
41 #include <sys/param.h>
42 #include <sys/socket.h>
43 #include <net/if.h>
44 #include <netinet/in.h>
45 #include <netinet/if_ether.h>
46
47 #include <netinet/in_systm.h>
48
49 #include <string.h>
50
51 #include "stand.h"
52 #include "net.h"
53 #include "netif.h"
54
55
56 static ssize_t rarpsend(struct iodesc *, void *, size_t);
57 static ssize_t rarprecv(struct iodesc *, void **, void **, time_t, void *);
58
59 /*
60 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
61 */
62 int
rarp_getipaddress(int sock)63 rarp_getipaddress(int sock)
64 {
65 struct iodesc *d;
66 struct ether_arp *ap;
67 void *pkt;
68 struct {
69 u_char header[ETHER_SIZE];
70 struct {
71 struct ether_arp arp;
72 u_char pad[18]; /* 60 - sizeof(arp) */
73 } data;
74 } wbuf;
75
76 #ifdef RARP_DEBUG
77 if (debug)
78 printf("rarp: socket=%d\n", sock);
79 #endif
80 if (!(d = socktodesc(sock))) {
81 printf("rarp: bad socket. %d\n", sock);
82 return (-1);
83 }
84 #ifdef RARP_DEBUG
85 if (debug)
86 printf("rarp: d=%x\n", (u_int)d);
87 #endif
88
89 bzero((char*)&wbuf.data, sizeof(wbuf.data));
90 ap = &wbuf.data.arp;
91 ap->arp_hrd = htons(ARPHRD_ETHER);
92 ap->arp_pro = htons(ETHERTYPE_IP);
93 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
94 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
95 ap->arp_op = htons(ARPOP_REVREQUEST);
96 bcopy(d->myea, ap->arp_sha, 6);
97 bcopy(d->myea, ap->arp_tha, 6);
98 pkt = NULL;
99
100 if (sendrecv(d,
101 rarpsend, &wbuf.data, sizeof(wbuf.data),
102 rarprecv, &pkt, (void *)&ap, NULL) < 0) {
103 printf("No response for RARP request\n");
104 return (-1);
105 }
106
107 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip));
108 #if 0
109 /* XXX - Can NOT assume this is our root server! */
110 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip));
111 #endif
112 free(pkt);
113
114 /* Compute our "natural" netmask. */
115 if (IN_CLASSA(myip.s_addr))
116 netmask = IN_CLASSA_NET;
117 else if (IN_CLASSB(myip.s_addr))
118 netmask = IN_CLASSB_NET;
119 else
120 netmask = IN_CLASSC_NET;
121
122 d->myip = myip;
123 return (0);
124 }
125
126 /*
127 * Broadcast a RARP request (i.e. who knows who I am)
128 */
129 static ssize_t
rarpsend(struct iodesc * d,void * pkt,size_t len)130 rarpsend(struct iodesc *d, void *pkt, size_t len)
131 {
132
133 #ifdef RARP_DEBUG
134 if (debug)
135 printf("rarpsend: called\n");
136 #endif
137
138 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP));
139 }
140
141 /*
142 * Returns 0 if this is the packet we're waiting for
143 * else -1 (and errno == 0)
144 */
145 static ssize_t
rarprecv(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,void * extra)146 rarprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft,
147 void *extra)
148 {
149 ssize_t n;
150 struct ether_arp *ap;
151 void *ptr = NULL;
152 uint16_t etype; /* host order */
153
154 #ifdef RARP_DEBUG
155 if (debug)
156 printf("rarprecv: ");
157 #endif
158
159 n = readether(d, &ptr, (void **)&ap, tleft, &etype);
160 errno = 0; /* XXX */
161 if (n == -1 || n < sizeof(struct ether_arp)) {
162 #ifdef RARP_DEBUG
163 if (debug)
164 printf("bad len=%d\n", n);
165 #endif
166 free(ptr);
167 return (-1);
168 }
169
170 if (etype != ETHERTYPE_REVARP) {
171 #ifdef RARP_DEBUG
172 if (debug)
173 printf("bad type=0x%x\n", etype);
174 #endif
175 free(ptr);
176 return (-1);
177 }
178
179 if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
180 ap->arp_pro != htons(ETHERTYPE_IP) ||
181 ap->arp_hln != sizeof(ap->arp_sha) ||
182 ap->arp_pln != sizeof(ap->arp_spa) )
183 {
184 #ifdef RARP_DEBUG
185 if (debug)
186 printf("bad hrd/pro/hln/pln\n");
187 #endif
188 free(ptr);
189 return (-1);
190 }
191
192 if (ap->arp_op != htons(ARPOP_REVREPLY)) {
193 #ifdef RARP_DEBUG
194 if (debug)
195 printf("bad op=0x%x\n", ntohs(ap->arp_op));
196 #endif
197 free(ptr);
198 return (-1);
199 }
200
201 /* Is the reply for our Ethernet address? */
202 if (bcmp(ap->arp_tha, d->myea, 6)) {
203 #ifdef RARP_DEBUG
204 if (debug)
205 printf("unwanted address\n");
206 #endif
207 free(ptr);
208 return (-1);
209 }
210
211 /* We have our answer. */
212 #ifdef RARP_DEBUG
213 if (debug)
214 printf("got it\n");
215 #endif
216 *pkt = ptr;
217 *payload = ap;
218 return (n);
219 }
220