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 1.5 1996/05/11 20:48:09 phk 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 <net/if_var.h>
39#include <net/route.h>
40#include <net/if_dl.h>
41#include <netinet/in.h>
42#include <stdio.h>
43#include <fcntl.h>
44#ifdef __bsdi__
45#include <kvm.h>
46#endif
47#include <net/if_types.h>
48#include <netinet/in_var.h>
49#include <netinet/if_ether.h>
50#include "log.h"
51
52#if RTM_VERSION >= 3
53#include <netinet/if_ether.h>
54#endif
55
56static int rtm_seq;
57
58static int get_ether_addr __P((int, u_long, struct sockaddr_dl *));
59
60#define BCOPY(s, d, l) memcpy(d, s, l)
61#define BZERO(s, n) memset(s, 0, n)
62/*
63 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
64 * if it exists.
65 */
66#define SET_SA_FAMILY(addr, family) \
67 BZERO((char *) &(addr), sizeof(addr)); \
68 addr.sa_family = (family); \
69 addr.sa_len = sizeof(addr);
70
71
72#if RTM_VERSION >= 3
73
74/*
75 * sifproxyarp - Make a proxy ARP entry for the peer.
76 */
77static struct {
78 struct rt_msghdr hdr;
79 struct sockaddr_inarp dst;
80 struct sockaddr_dl hwa;
81 char extra[128];
82} arpmsg;
83
84static int arpmsg_valid;
85
86int
87sifproxyarp(unit, hisaddr)
88 int unit;
89 u_long hisaddr;
90{
91 int routes;
92
93 /*
94 * Get the hardware address of an interface on the same subnet
95 * as our local address.
96 */
97 memset(&arpmsg, 0, sizeof(arpmsg));
98 if (!get_ether_addr(unit, hisaddr, &arpmsg.hwa)) {
99 logprintf("Cannot determine ethernet address for proxy ARP\n");
100 return 0;
101 }
102
103 if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
104 logprintf("sifproxyarp: opening routing socket: \n");
105 return 0;
106 }
107
108 arpmsg.hdr.rtm_type = RTM_ADD;
109 arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC;
110 arpmsg.hdr.rtm_version = RTM_VERSION;
111 arpmsg.hdr.rtm_seq = ++rtm_seq;
112 arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY;
113 arpmsg.hdr.rtm_inits = RTV_EXPIRE;
114 arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp);
115 arpmsg.dst.sin_family = AF_INET;
116 arpmsg.dst.sin_addr.s_addr = hisaddr;
117 arpmsg.dst.sin_other = SIN_PROXY;
118
119 arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
120 + arpmsg.hwa.sdl_len;
121 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
122 logprintf("add proxy arp entry: \n");
123 close(routes);
124 return 0;
125 }
126
127 close(routes);
128 arpmsg_valid = 1;
129 return 1;
130}
131
132/*
133 * cifproxyarp - Delete the proxy ARP entry for the peer.
134 */
135int
136cifproxyarp(unit, hisaddr)
137 int unit;
138 u_long hisaddr;
139{
140 int routes;
141
142 if (!arpmsg_valid)
143 return 0;
144 arpmsg_valid = 0;
145
146 arpmsg.hdr.rtm_type = RTM_DELETE;
147 arpmsg.hdr.rtm_seq = ++rtm_seq;
148
149 if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
150 logprintf("sifproxyarp: opening routing socket: \n");
151 return 0;
152 }
153
154 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
155 logprintf("delete proxy arp entry: \n");
156 close(routes);
157 return 0;
158 }
159
160 close(routes);
161 return 1;
162}
163
164#else /* RTM_VERSION */
165
166/*
167 * sifproxyarp - Make a proxy ARP entry for the peer.
168 */
169int
170sifproxyarp(unit, hisaddr)
171 int unit;
172 u_long hisaddr;
173{
174 struct arpreq arpreq;
175 struct {
176 struct sockaddr_dl sdl;
177 char space[128];
178 } dls;
179
180 BZERO(&arpreq, sizeof(arpreq));
181
182 /*
183 * Get the hardware address of an interface on the same subnet
184 * as our local address.
185 */
186 if (!get_ether_addr(unit, hisaddr, &dls.sdl)) {
187 LogPrintf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n");
188 return 0;
189 }
190
191 arpreq.arp_ha.sa_len = sizeof(struct sockaddr);
192 arpreq.arp_ha.sa_family = AF_UNSPEC;
193 BCOPY(LLADDR(&dls.sdl), arpreq.arp_ha.sa_data, dls.sdl.sdl_alen);
194 SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
195 ((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = hisaddr;
196 arpreq.arp_flags = ATF_PERM | ATF_PUBL;
197 if (ioctl(unit, SIOCSARP, (caddr_t)&arpreq) < 0) {
198 fprintf(stderr, "ioctl(SIOCSARP): \n");
199 return 0;
200 }
201
202 return 1;
203}
204
205/*
206 * cifproxyarp - Delete the proxy ARP entry for the peer.
207 */
208int
209cifproxyarp(unit, hisaddr)
210 int unit;
211 u_long hisaddr;
212{
213 struct arpreq arpreq;
214
215 BZERO(&arpreq, sizeof(arpreq));
216 SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
217 ((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = hisaddr;
218 if (ioctl(unit, SIOCDARP, (caddr_t)&arpreq) < 0) {
219 fprintf(stderr, "ioctl(SIOCDARP): \n");
220 return 0;
221 }
222 return 1;
223}
224#endif /* RTM_VERSION */
225
226
227/*
228 * get_ether_addr - get the hardware address of an interface on the
229 * the same subnet as ipaddr.
230 */
231#define MAX_IFS 32
232
233int
234get_ether_addr(s, ipaddr, hwaddr)
235 int s;
236 u_long ipaddr;
237 struct sockaddr_dl *hwaddr;
238{
239 struct ifreq *ifr, *ifend, *ifp;
240 u_long ina, mask;
241 struct sockaddr_dl *dla;
242 struct ifreq ifreq;
243 struct ifconf ifc;
244 struct ifreq ifs[MAX_IFS];
245
246 ifc.ifc_len = sizeof(ifs);
247 ifc.ifc_req = ifs;
248 if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
249 fprintf(stderr, "ioctl(SIOCGIFCONF): \n");
250 return 0;
251 }
252
253 /*
254 * Scan through looking for an interface with an Internet
255 * address on the same subnet as `ipaddr'.
256 */
257 ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
258 for (ifr = ifc.ifc_req; ifr < ifend; ) {
259 if (ifr->ifr_addr.sa_family == AF_INET) {
260 ina = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;
261 strncpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name));
262 /*
263 * Check that the interface is up, and not point-to-point
264 * or loopback.
265 */
266 if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0)
267 continue;
268 if ((ifreq.ifr_flags &
269 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|IFF_LOOPBACK|IFF_NOARP))
270 != (IFF_UP|IFF_BROADCAST))
271 goto nextif;
272 /*
273 * Get its netmask and check that it's on the right subnet.
274 */
275 if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0)
276 continue;
277 mask = ((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr.s_addr;
278 if ((ipaddr & mask) != (ina & mask))
279 goto nextif;
280
281 break;
282 }
283nextif:
284 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
285 }
286
287 if (ifr >= ifend)
288 return 0;
289 LogPrintf(LOG_PHASE_BIT, "found interface %s for proxy arp\n", ifr->ifr_name);
290
291 /*
292 * Now scan through again looking for a link-level address
293 * for this interface.
294 */
295 ifp = ifr;
296 for (ifr = ifc.ifc_req; ifr < ifend; ) {
297 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
298 && ifr->ifr_addr.sa_family == AF_LINK) {
299 /*
300 * Found the link-level address - copy it out
301 */
302 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
303#ifdef __bsdi__
304 if (dla->sdl_alen == 0)
305 kmemgetether(ifr->ifr_name, dla);
306#endif
307 BCOPY(dla, hwaddr, dla->sdl_len);
308 return 1;
309 }
310 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
311 }
312
313 return 0;
314}
315
316#ifdef __bsdi__
317#include <nlist.h>
318
319struct nlist nl[] = {
320#define N_IFNET 0
321 { "_ifnet" },
322 "",
323};
324
325
326kvm_t *kvmd;
327
328/*
329 * Read kernel memory, return 0 on success.
330 */
331int
332kread(addr, buf, size)
333 u_long addr;
334 char *buf;
335 int size;
336{
337
338 if (kvm_read(kvmd, addr, buf, size) != size) {
339 /* XXX this duplicates kvm_read's error printout */
340 (void)fprintf(stderr, "kvm_read %s\n",
341 kvm_geterr(kvmd));
342 return (-1);
343 }
344 return (0);
345}
346
347kmemgetether(ifname, dlo)
348char *ifname;
349struct sockaddr_dl *dlo;
350{
351 struct ifnet ifnet;
352 int n;
353 u_long addr, ifaddraddr, ifnetfound, ifaddrfound;
354 char name[32];
355 struct sockaddr *sa;
356 char *cp;
357 struct sockaddr_dl *sdl;
358 union {
359 struct ifaddr ifa;
360 struct in_ifaddr in;
361 } ifaddr;
362 struct arpcom ac;
363
364 kvmd = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL);
365 if (kvmd) {
366 n = kvm_nlist(kvmd, nl);
367 if (n >= 0) {
368 addr = nl[N_IFNET].n_value;
369 kread(addr, (char *)&addr, sizeof(addr));
370 ifaddraddr = ifnetfound = 0;
371 while (addr || ifaddraddr) {
372 ifnetfound = addr;
373 if (ifaddraddr == 0) {
374 if (kread(addr, (char *)&ifnet, sizeof(ifnet)) ||
375 kread((u_long)ifnet.if_name, name, 16))
376 return;
377 name[15] = 0;
378 addr = (u_long) ifnet.if_next;
379 cp = (char *)index(name, '\0');
380 cp += sprintf(cp, "%d", ifnet.if_unit);
381 *cp = '\0';
382 ifaddraddr = (u_long)ifnet.if_addrlist;
383 }
384 ifaddrfound = ifaddraddr;
385 if (ifaddraddr) {
386 if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
387 ifaddraddr = 0;
388 continue;
389 }
390#define CP(x) ((char *)(x))
391 cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) + CP(&ifaddr);
392 sa = (struct sockaddr *)cp;
393 if (sa->sa_family == AF_LINK && strcmp(ifname, name) == 0) {
394 sdl = (struct sockaddr_dl *)sa;
395 cp = (char *)LLADDR(sdl);
396 n = sdl->sdl_alen;
397 if (ifnet.if_type == IFT_ETHER) {
398 if (n == 0) {
399 kread(ifnetfound, (char *)&ac, sizeof(ac));
400 cp = (char *)LLADDR(sdl);
401 bcopy((char *)ac.ac_enaddr, cp, 6);
402 sdl->sdl_alen = 6;
403 }
404 bcopy(sdl, dlo, sizeof(*sdl));
405 return;
406 }
407 }
408 ifaddraddr = (u_long)ifaddr.ifa.ifa_next;
409 }
410 }
411 }
412 }
413}
414#endif
415
416#ifdef DEBUG
417main()
418{
419 u_long ipaddr;
420 int s;
421
422 s = socket(AF_INET, SOCK_DGRAM, 0);
423 ipaddr = inet_addr("192.168.1.32");
424 sifproxyarp(s, ipaddr);
425 close(s);
426}
427#endif