1/*
2 * sys-bsd.c - System-dependent procedures for setting up
3 * PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.)
4 *
5 * Copyright (c) 1989 Carnegie Mellon University.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by Carnegie Mellon University. The name of the
14 * University may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $Id: arp.c,v 1.9 1997/02/22 16:09:56 peter Exp $
21 *
22 */
23
24/*
25 * TODO:
26 */
27
28#include <sys/ioctl.h>
29#include <sys/types.h>
30#include <sys/uio.h>
31#include <sys/socket.h>
32#include <sys/time.h>
33#include <sys/errno.h>
34#include <unistd.h>
35#include <string.h>
36
37#include <net/if.h>
38#include <osreldate.h>
39#if __FreeBSD_version >= 199702
40#include <net/if_var.h>
41#endif
42#include <net/route.h>
43#include <net/if_dl.h>
44#include <netinet/in.h>
45#include <stdio.h>
46#include <fcntl.h>
47#ifdef __bsdi__
48#include <kvm.h>
49#endif
50#include <net/if_types.h>
51#include <netinet/in_var.h>
52#include <netinet/if_ether.h>
53#include "log.h"
54
55#if RTM_VERSION >= 3
56#include <netinet/if_ether.h>
57#endif
58
59static int rtm_seq;
60
61static int get_ether_addr __P((int, u_long, struct sockaddr_dl *));
62
63#define BCOPY(s, d, l) memcpy(d, s, l)
64#define BZERO(s, n) memset(s, 0, n)
65/*
66 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
67 * if it exists.
68 */
69#define SET_SA_FAMILY(addr, family) \
70 BZERO((char *) &(addr), sizeof(addr)); \
71 addr.sa_family = (family); \
72 addr.sa_len = sizeof(addr);
73
74
75#if RTM_VERSION >= 3
76
77/*
78 * sifproxyarp - Make a proxy ARP entry for the peer.
79 */
80static struct {
81 struct rt_msghdr hdr;
82 struct sockaddr_inarp dst;
83 struct sockaddr_dl hwa;
84 char extra[128];
85} arpmsg;
86
87static int arpmsg_valid;
88
89int
90sifproxyarp(unit, hisaddr)
91 int unit;
92 u_long hisaddr;
93{
94 int routes;
95
96 /*
97 * Get the hardware address of an interface on the same subnet
98 * as our local address.
99 */
100 memset(&arpmsg, 0, sizeof(arpmsg));
101 if (!get_ether_addr(unit, hisaddr, &arpmsg.hwa)) {
102 logprintf("Cannot determine ethernet address for proxy ARP\n");
103 return 0;
104 }
105
106 if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
107 logprintf("sifproxyarp: opening routing socket: \n");
108 return 0;
109 }
110
111 arpmsg.hdr.rtm_type = RTM_ADD;
112 arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC;
113 arpmsg.hdr.rtm_version = RTM_VERSION;
114 arpmsg.hdr.rtm_seq = ++rtm_seq;
115 arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY;
116 arpmsg.hdr.rtm_inits = RTV_EXPIRE;
117 arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp);
118 arpmsg.dst.sin_family = AF_INET;
119 arpmsg.dst.sin_addr.s_addr = hisaddr;
120 arpmsg.dst.sin_other = SIN_PROXY;
121
122 arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
123 + arpmsg.hwa.sdl_len;
124 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
125 logprintf("add proxy arp entry: \n");
126 close(routes);
127 return 0;
128 }
129
130 close(routes);
131 arpmsg_valid = 1;
132 return 1;
133}
134
135/*
136 * cifproxyarp - Delete the proxy ARP entry for the peer.
137 */
138int
139cifproxyarp(unit, hisaddr)
140 int unit;
141 u_long hisaddr;
142{
143 int routes;
144
145 if (!arpmsg_valid)
146 return 0;
147 arpmsg_valid = 0;
148
149 arpmsg.hdr.rtm_type = RTM_DELETE;
150 arpmsg.hdr.rtm_seq = ++rtm_seq;
151
152 if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
153 logprintf("sifproxyarp: opening routing socket: \n");
154 return 0;
155 }
156
157 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
158 logprintf("delete proxy arp entry: \n");
159 close(routes);
160 return 0;
161 }
162
163 close(routes);
164 return 1;
165}
166
167#else /* RTM_VERSION */
168
169/*
170 * sifproxyarp - Make a proxy ARP entry for the peer.
171 */
172int
173sifproxyarp(unit, hisaddr)
174 int unit;
175 u_long hisaddr;
176{
177 struct arpreq arpreq;
178 struct {
179 struct sockaddr_dl sdl;
180 char space[128];
181 } dls;
182
183 BZERO(&arpreq, sizeof(arpreq));
184
185 /*
186 * Get the hardware address of an interface on the same subnet
187 * as our local address.
188 */
189 if (!get_ether_addr(unit, hisaddr, &dls.sdl)) {
190 LogPrintf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n");
191 return 0;
192 }
193
194 arpreq.arp_ha.sa_len = sizeof(struct sockaddr);
195 arpreq.arp_ha.sa_family = AF_UNSPEC;
196 BCOPY(LLADDR(&dls.sdl), arpreq.arp_ha.sa_data, dls.sdl.sdl_alen);
197 SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
198 ((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = hisaddr;
199 arpreq.arp_flags = ATF_PERM | ATF_PUBL;
200 if (ioctl(unit, SIOCSARP, (caddr_t)&arpreq) < 0) {
201 fprintf(stderr, "ioctl(SIOCSARP): \n");
202 return 0;
203 }
204
205 return 1;
206}
207
208/*
209 * cifproxyarp - Delete the proxy ARP entry for the peer.
210 */
211int
212cifproxyarp(unit, hisaddr)
213 int unit;
214 u_long hisaddr;
215{
216 struct arpreq arpreq;
217
218 BZERO(&arpreq, sizeof(arpreq));
219 SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
220 ((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = hisaddr;
221 if (ioctl(unit, SIOCDARP, (caddr_t)&arpreq) < 0) {
222 fprintf(stderr, "ioctl(SIOCDARP): \n");
223 return 0;
224 }
225 return 1;
226}
227#endif /* RTM_VERSION */
228
229
230/*
231 * get_ether_addr - get the hardware address of an interface on the
232 * the same subnet as ipaddr.
233 */
234#define MAX_IFS 32
235
236int
237get_ether_addr(s, ipaddr, hwaddr)
238 int s;
239 u_long ipaddr;
240 struct sockaddr_dl *hwaddr;
241{
242 struct ifreq *ifr, *ifend, *ifp;
243 u_long ina, mask;
244 struct sockaddr_dl *dla;
245 struct ifreq ifreq;
246 struct ifconf ifc;
247 struct ifreq ifs[MAX_IFS];
248
249 ifc.ifc_len = sizeof(ifs);
250 ifc.ifc_req = ifs;
251 if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
252 fprintf(stderr, "ioctl(SIOCGIFCONF): \n");
253 return 0;
254 }
255
256 /*
257 * Scan through looking for an interface with an Internet
258 * address on the same subnet as `ipaddr'.
259 */
260 ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
261 for (ifr = ifc.ifc_req; ifr < ifend; ) {
262 if (ifr->ifr_addr.sa_family == AF_INET) {
263 ina = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;
264 strncpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name));
265 ifreq.ifr_name[sizeof(ifreq.ifr_name)-1]='\0';
266 /*
267 * Check that the interface is up, and not point-to-point
268 * or loopback.
269 */
270 if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0)
271 continue;
272 if ((ifreq.ifr_flags &
273 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|IFF_LOOPBACK|IFF_NOARP))
274 != (IFF_UP|IFF_BROADCAST))
275 goto nextif;
276 /*
277 * Get its netmask and check that it's on the right subnet.
278 */
279 if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0)
280 continue;
281 mask = ((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr.s_addr;
282 if ((ipaddr & mask) != (ina & mask))
283 goto nextif;
284
285 break;
286 }
287nextif:
288 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
289 }
290
291 if (ifr >= ifend)
292 return 0;
293 LogPrintf(LOG_PHASE_BIT, "found interface %s for proxy arp\n", ifr->ifr_name);
294
295 /*
296 * Now scan through again looking for a link-level address
297 * for this interface.
298 */
299 ifp = ifr;
300 for (ifr = ifc.ifc_req; ifr < ifend; ) {
301 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
302 && ifr->ifr_addr.sa_family == AF_LINK) {
303 /*
304 * Found the link-level address - copy it out
305 */
306 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
307#ifdef __bsdi__
308 if (dla->sdl_alen == 0)
309 kmemgetether(ifr->ifr_name, dla);
310#endif
311 BCOPY(dla, hwaddr, dla->sdl_len);
312 return 1;
313 }
314 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
315 }
316
317 return 0;
318}
319
320#ifdef __bsdi__
321#include <nlist.h>
322
323struct nlist nl[] = {
324#define N_IFNET 0
325 { "_ifnet" },
326 "",
327};
328
329
330kvm_t *kvmd;
331
332/*
333 * Read kernel memory, return 0 on success.
334 */
335int
336kread(addr, buf, size)
337 u_long addr;
338 char *buf;
339 int size;
340{
341
342 if (kvm_read(kvmd, addr, buf, size) != size) {
343 /* XXX this duplicates kvm_read's error printout */
344 (void)fprintf(stderr, "kvm_read %s\n",
345 kvm_geterr(kvmd));
346 return (-1);
347 }
348 return (0);
349}
350
351kmemgetether(ifname, dlo)
352char *ifname;
353struct sockaddr_dl *dlo;
354{
355 struct ifnet ifnet;
356 int n;
357 u_long addr, ifaddraddr, ifnetfound, ifaddrfound;
358 char name[16+32];
359 struct sockaddr *sa;
360 char *cp;
361 struct sockaddr_dl *sdl;
362 union {
363 struct ifaddr ifa;
364 struct in_ifaddr in;
365 } ifaddr;
366 struct arpcom ac;
367
368 kvmd = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL);
369 if (kvmd) {
370 n = kvm_nlist(kvmd, nl);
371 if (n >= 0) {
372 addr = nl[N_IFNET].n_value;
373 kread(addr, (char *)&addr, sizeof(addr));
374 ifaddraddr = ifnetfound = 0;
375 while (addr || ifaddraddr) {
376 ifnetfound = addr;
377 if (ifaddraddr == 0) {
378 if (kread(addr, (char *)&ifnet, sizeof(ifnet)) ||
379 kread((u_long)ifnet.if_name, name, 16))
380 return;
381 name[15] = 0;
382 addr = (u_long) ifnet.if_next;
383 cp = (char *)index(name, '\0');
384 cp += sprintf(cp, "%d", ifnet.if_unit);
385 *cp = '\0';
386 ifaddraddr = (u_long)ifnet.if_addrlist;
387 }
388 ifaddrfound = ifaddraddr;
389 if (ifaddraddr) {
390 if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
391 ifaddraddr = 0;
392 continue;
393 }
394#define CP(x) ((char *)(x))
395 cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) + CP(&ifaddr);
396 sa = (struct sockaddr *)cp;
397 if (sa->sa_family == AF_LINK && strcmp(ifname, name) == 0) {
398 sdl = (struct sockaddr_dl *)sa;
399 cp = (char *)LLADDR(sdl);
400 n = sdl->sdl_alen;
401 if (ifnet.if_type == IFT_ETHER) {
402 if (n == 0) {
403 kread(ifnetfound, (char *)&ac, sizeof(ac));
404 cp = (char *)LLADDR(sdl);
405 bcopy((char *)ac.ac_enaddr, cp, 6);
406 sdl->sdl_alen = 6;
407 }
408 bcopy(sdl, dlo, sizeof(*sdl));
409 return;
410 }
411 }
412 ifaddraddr = (u_long)ifaddr.ifa.ifa_next;
413 }
414 }
415 }
416 }
417}
418#endif
419
420#ifdef DEBUG
421main()
422{
423 u_long ipaddr;
424 int s;
425
426 s = socket(AF_INET, SOCK_DGRAM, 0);
427 ipaddr = inet_addr("192.168.1.32");
428 sifproxyarp(s, ipaddr);
429 close(s);
430}
431#endif