1 /* $NetBSD: getether.c,v 1.10 2024/09/08 09:36:53 rillig Exp $ */
2
3 #include <sys/cdefs.h>
4 #ifndef lint
5 __RCSID("$NetBSD: getether.c,v 1.10 2024/09/08 09:36:53 rillig Exp $");
6 #endif
7
8 /*
9 * getether.c : get the ethernet address of an interface
10 *
11 * All of this code is quite system-specific. As you may well
12 * guess, it took a good bit of detective work to figure out!
13 *
14 * If you figure out how to do this on another system,
15 * please let me know. <gwr@mc.com>
16 */
17
18 #include <sys/types.h>
19 #include <sys/socket.h>
20
21 #include <ctype.h>
22 #include <string.h>
23 #include <strings.h>
24 #include <syslog.h>
25 #include <unistd.h>
26
27 #include "report.h"
28 #define EALEN 6
29
30 extern int getether(char *, char *);
31
32 #if defined(ultrix) || (defined(__osf__) && defined(__alpha))
33 /*
34 * This is really easy on Ultrix! Thanks to
35 * Harald Lundberg <hl@tekla.fi> for this code.
36 *
37 * The code here is not specific to the Alpha, but that was the
38 * only symbol we could find to identify DEC's version of OSF.
39 * (Perhaps we should just define DEC in the Makefile... -gwr)
40 */
41
42 #include <sys/ioctl.h>
43 #include <net/if.h> /* struct ifdevea */
44
45 int
getether(char * ifname,char * eap)46 getether(char *ifname, char *eap)
47 {
48 int rc = -1;
49 int fd;
50 struct ifdevea phys;
51
52 bzero(&phys, sizeof(phys));
53 strncpy(phys.ifr_name, ifname, sizeof(phys.ifr_name));
54 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
55 report(LOG_ERR, "getether: socket(INET,DGRAM) failed");
56 return -1;
57 }
58 if (ioctl(fd, SIOCRPHYSADDR, &phys) < 0) {
59 report(LOG_ERR, "getether: ioctl SIOCRPHYSADDR failed");
60 } else {
61 bcopy(&phys.current_pa[0], eap, EALEN);
62 rc = 0;
63 }
64 close(fd);
65 return rc;
66 }
67
68 #define GETETHER
69 #endif /* ultrix|osf1 */
70
71
72 #ifdef SUNOS
73
74 #include <sys/sockio.h>
75 #include <sys/time.h> /* needed by net_if.h */
76 #include <net/nit_if.h> /* for NIOCBIND */
77 #include <net/if.h> /* for struct ifreq */
78
79 /* ifname: interface name from ifconfig structure */
80 /* eap: Ether address (output) */
getether(char * ifname,char * eap)81 getether(char *ifname, char *eap)
82 {
83 int rc = -1;
84
85 struct ifreq ifrnit;
86 int nit;
87
88 bzero((char *) &ifrnit, sizeof(ifrnit));
89 strncpy(&ifrnit.ifr_name[0], ifname, IFNAMSIZ);
90
91 nit = open("/dev/nit", 0);
92 if (nit < 0) {
93 report(LOG_ERR, "getether: open /dev/nit: %s",
94 get_errmsg());
95 return rc;
96 }
97 do {
98 if (ioctl(nit, NIOCBIND, &ifrnit) < 0) {
99 report(LOG_ERR, "getether: NIOCBIND on nit");
100 break;
101 }
102 if (ioctl(nit, SIOCGIFADDR, &ifrnit) < 0) {
103 report(LOG_ERR, "getether: SIOCGIFADDR on nit");
104 break;
105 }
106 bcopy(&ifrnit.ifr_addr.sa_data[0], eap, EALEN);
107 rc = 0;
108 } while (0);
109 close(nit);
110 return rc;
111 }
112
113 #define GETETHER
114 #endif /* SUNOS */
115
116
117 #if defined(__386BSD__) || defined(__NetBSD__)
118 /* Thanks to John Brezak <brezak@ch.hp.com> for this code. */
119 #include <sys/ioctl.h>
120 #include <net/if.h>
121 #include <net/if_dl.h>
122 #include <net/if_types.h>
123
124 /* ifname: interface name from ifconfig structure */
125 /* eap: Ether address (output) */
126 int
getether(char * ifname,char * eap)127 getether(char *ifname, char *eap)
128 {
129 int fd, rc = -1;
130 int n;
131 struct ifreq ibuf[16];
132 struct ifconf ifc;
133 struct ifreq *ifrp, *ifend;
134
135 /* Fetch the interface configuration */
136 fd = socket(AF_INET, SOCK_DGRAM, 0);
137 if (fd < 0) {
138 report(LOG_ERR, "getether: socket %s: %s", ifname, get_errmsg());
139 return (fd);
140 }
141 ifc.ifc_len = sizeof(ibuf);
142 ifc.ifc_buf = (caddr_t) ibuf;
143 if (ioctl(fd, SIOCGIFCONF, (char *) &ifc) < 0 ||
144 ifc.ifc_len < (int)sizeof(struct ifreq)) {
145 report(LOG_ERR, "getether: SIOCGIFCONF: %s", get_errmsg());
146 goto out;
147 }
148 /* Search interface configuration list for link layer address. */
149 ifrp = ibuf;
150 ifend = (struct ifreq *) ((char *) ibuf + ifc.ifc_len);
151 while (ifrp < ifend) {
152 /* Look for interface */
153 if (strcmp(ifname, ifrp->ifr_name) == 0 &&
154 ifrp->ifr_addr.sa_family == AF_LINK &&
155 ((struct sockaddr_dl *) &ifrp->ifr_addr)->sdl_type == IFT_ETHER) {
156 bcopy(LLADDR((struct sockaddr_dl *) &ifrp->ifr_addr), eap, EALEN);
157 rc = 0;
158 break;
159 }
160 /* Bump interface config pointer */
161 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
162 if (n < (int)sizeof(*ifrp))
163 n = sizeof(*ifrp);
164 ifrp = (struct ifreq *) ((char *) ifrp + n);
165 }
166
167 out:
168 close(fd);
169 return (rc);
170 }
171
172 #define GETETHER
173 #endif /* __NetBSD__ */
174
175
176 #ifdef SVR4
177 /*
178 * This is for "Streams TCP/IP" by Lachman Associates.
179 * They sure made this cumbersome! -gwr
180 */
181
182 #include <sys/sockio.h>
183 #include <sys/dlpi.h>
184 #include <stropts.h>
185 #ifndef NULL
186 #define NULL 0
187 #endif
188
189 /* ifname: interface name from ifconfig structure */
190 /* eap: Ether address (output) */
getether(char * ifname,char * eap)191 getether(char *ifname, char *eap)
192 {
193 int rc = -1;
194 char devname[32];
195 char tmpbuf[sizeof(union DL_primitives) + 16];
196 struct strbuf cbuf;
197 int fd, flags;
198 union DL_primitives *dlp;
199 char *enaddr;
200 int unit = -1; /* which unit to attach */
201
202 snprintf(devname, sizeof(devname), "/dev/%s", ifname);
203 fd = open(devname, 2);
204 if (fd < 0) {
205 /* Try without the trailing digit. */
206 char *p = devname + 5;
207 while (isalpha(*p))
208 p++;
209 if (isdigit(*p)) {
210 unit = *p - '0';
211 *p = '\0';
212 }
213 fd = open(devname, 2);
214 if (fd < 0) {
215 report(LOG_ERR, "getether: open %s: %s",
216 devname, get_errmsg());
217 return rc;
218 }
219 }
220 #ifdef DL_ATTACH_REQ
221 /*
222 * If this is a "Style 2" DLPI, then we must "attach" first
223 * to tell the driver which unit (board, port) we want.
224 * For now, decide this based on the device name.
225 * (Should do "info_req" and check dl_provider_style ...)
226 */
227 if (unit >= 0) {
228 memset(tmpbuf, 0, sizeof(tmpbuf));
229 dlp = (union DL_primitives *) tmpbuf;
230 dlp->dl_primitive = DL_ATTACH_REQ;
231 dlp->attach_req.dl_ppa = unit;
232 cbuf.buf = tmpbuf;
233 cbuf.len = DL_ATTACH_REQ_SIZE;
234 if (putmsg(fd, &cbuf, NULL, 0) < 0) {
235 report(LOG_ERR, "getether: attach: putmsg: %s", get_errmsg());
236 goto out;
237 }
238 /* Recv the ack. */
239 cbuf.buf = tmpbuf;
240 cbuf.maxlen = sizeof(tmpbuf);
241 flags = 0;
242 if (getmsg(fd, &cbuf, NULL, &flags) < 0) {
243 report(LOG_ERR, "getether: attach: getmsg: %s", get_errmsg());
244 goto out;
245 }
246 /*
247 * Check the type, etc.
248 */
249 if (dlp->dl_primitive == DL_ERROR_ACK) {
250 report(LOG_ERR, "getether: attach: dlpi_errno=%d, unix_errno=%d",
251 dlp->error_ack.dl_errno,
252 dlp->error_ack.dl_unix_errno);
253 goto out;
254 }
255 if (dlp->dl_primitive != DL_OK_ACK) {
256 report(LOG_ERR, "getether: attach: not OK or ERROR");
257 goto out;
258 }
259 } /* unit >= 0 */
260 #endif /* DL_ATTACH_REQ */
261
262 /*
263 * Get the Ethernet address the same way the ARP module
264 * does when it is pushed onto a new stream (bind).
265 * One should instead be able just do a dl_info_req
266 * but many drivers do not supply the hardware address
267 * in the response to dl_info_req (they MUST supply it
268 * for dl_bind_ack because the ARP module requires it).
269 */
270 memset(tmpbuf, 0, sizeof(tmpbuf));
271 dlp = (union DL_primitives *) tmpbuf;
272 dlp->dl_primitive = DL_BIND_REQ;
273 dlp->bind_req.dl_sap = 0x8FF; /* XXX - Unused SAP */
274 cbuf.buf = tmpbuf;
275 cbuf.len = DL_BIND_REQ_SIZE;
276 if (putmsg(fd, &cbuf, NULL, 0) < 0) {
277 report(LOG_ERR, "getether: bind: putmsg: %s", get_errmsg());
278 goto out;
279 }
280 /* Recv the ack. */
281 cbuf.buf = tmpbuf;
282 cbuf.maxlen = sizeof(tmpbuf);
283 flags = 0;
284 if (getmsg(fd, &cbuf, NULL, &flags) < 0) {
285 report(LOG_ERR, "getether: bind: getmsg: %s", get_errmsg());
286 goto out;
287 }
288 /*
289 * Check the type, etc.
290 */
291 if (dlp->dl_primitive == DL_ERROR_ACK) {
292 report(LOG_ERR, "getether: bind: dlpi_errno=%d, unix_errno=%d",
293 dlp->error_ack.dl_errno,
294 dlp->error_ack.dl_unix_errno);
295 goto out;
296 }
297 if (dlp->dl_primitive != DL_BIND_ACK) {
298 report(LOG_ERR, "getether: bind: not OK or ERROR");
299 goto out;
300 }
301 if (dlp->bind_ack.dl_addr_offset == 0) {
302 report(LOG_ERR, "getether: bind: ack has no address");
303 goto out;
304 }
305 if (dlp->bind_ack.dl_addr_length < EALEN) {
306 report(LOG_ERR, "getether: bind: ack address truncated");
307 goto out;
308 }
309 /*
310 * Copy the Ethernet address out of the message.
311 */
312 enaddr = tmpbuf + dlp->bind_ack.dl_addr_offset;
313 memcpy(eap, enaddr, EALEN);
314 rc = 0;
315
316 out:
317 close(fd);
318 return rc;
319 }
320
321 #define GETETHER
322 #endif /* SVR4 */
323
324
325 #ifdef linux
326 /*
327 * This is really easy on Linux! This version (for linux)
328 * written by Nigel Metheringham <nigelm@ohm.york.ac.uk>
329 *
330 * The code is almost identical to the Ultrix code - however
331 * the names are different to confuse the innocent :-)
332 * Most of this code was stolen from the Ultrix bit above.
333 */
334
335 #include <sys/ioctl.h>
336 #include <net/if.h> /* struct ifreq */
337
338 /* In a properly configured system this should be either sys/socketio.h
339 or sys/sockios.h, but on my distribution these don't line up correctly */
340 #include <linux/sockios.h> /* Needed for IOCTL defs */
341
getether(char * ifname,char * eap)342 getether(char *ifname, char *eap)
343 {
344 int rc = -1;
345 int fd;
346 struct ifreq phys;
347
348 bzero(&phys, sizeof(phys));
349 strncpy(phys.ifr_name, ifname, sizeof(phys.ifr_name));
350 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
351 report(LOG_ERR, "getether: socket(INET,DGRAM) failed");
352 return -1;
353 }
354 if (ioctl(fd, SIOCGIFHWADDR, &phys) < 0) {
355 report(LOG_ERR, "getether: ioctl SIOCGIFHWADDR failed");
356 } else {
357 bcopy(phys.ifr_hwaddr, eap, EALEN);
358 rc = 0;
359 }
360 close(fd);
361 return rc;
362 }
363
364 #define GETETHER
365 #endif /* linux */
366
367
368 /* If we don't know how on this system, just return an error. */
369 #ifndef GETETHER
getether(char * ifname,char * eap)370 getether(char *ifname, char *eap)
371 {
372 return -1;
373 }
374
375 #endif /* !GETETHER */
376
377 /*
378 * Local Variables:
379 * tab-width: 4
380 * c-indent-level: 4
381 * c-argdecl-indent: 4
382 * c-continued-statement-offset: 4
383 * c-continued-brace-offset: -4
384 * c-label-offset: -4
385 * c-brace-offset: 0
386 * End:
387 */
388