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1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /*
23: * Copyright (c) 1988-1999 Apple Computer, Inc. All Rights Reserved
24: */
25:
26: /*
27: * bootp.c
28: * - be a BOOTP client over a particular interface to retrieve
29: * the IP address, netmask, and router
30: */
31:
32: /*
33: * Modification History
34: *
35: * February 19, 1999 Dieter Siegmund ([email protected])
36: * - completely rewritten
37: */
38:
39: #include <sys/param.h>
40: #include <sys/types.h>
41: #include <mach/boolean.h>
42: #include <sys/kernel.h>
43: #include <sys/errno.h>
44: #include <sys/file.h>
45: #include <sys/uio.h>
46: #include <sys/ioctl.h>
47: #include <sys/time.h>
48: #include <sys/mbuf.h>
49: #include <sys/vnode.h>
50: #include <sys/socket.h>
51: #include <sys/socketvar.h>
52: #include <net/if.h>
53: #include <net/if_dl.h>
54: #include <net/if_types.h>
55: #include <net/route.h>
56: #include <netinet/in.h>
57: #include <netinet/in_systm.h>
58: #include <netinet/if_ether.h>
59: #include <netinet/ip.h>
60: #include <netinet/ip_var.h>
61: #include <netinet/udp.h>
62: #include <netinet/udp_var.h>
63: #include <netinet/ip_icmp.h>
64: #include <netinet/bootp.h>
65: #include <sys/systm.h>
66: #include <sys/malloc.h>
67:
68: //#define BOOTP_DEBUG
69:
70: #ifdef BOOTP_DEBUG
71: #define dprintf(x) printf x;
72: #else BOOTP_DEBUG
73: #define dprintf(x)
74: #endif BOOTP_DEBUG
75:
76: /* ip address formatting macros */
77: #define IP_FORMAT "%d.%d.%d.%d"
78: #define IP_CH(ip) ((u_char *)ip)
79: #define IP_LIST(ip) IP_CH(ip)[0],IP_CH(ip)[1],IP_CH(ip)[2],IP_CH(ip)[3]
80:
81: /* tag values (from RFC 2132) */
82: #define TAG_PAD 0
83: #define TAG_END 255
84: #define TAG_SUBNET_MASK 1
85: #define TAG_ROUTER 3
86: #define RFC_OPTIONS_MAGIC { 99, 130, 83, 99 }
87: static unsigned char rfc_magic[4] = RFC_OPTIONS_MAGIC;
88:
89:
90: static struct sockaddr_in blank_sin = { sizeof(struct sockaddr_in),
91: AF_INET };
92:
93: static __inline__ void
94: print_reply(struct bootp *bp, int bp_len)
95: {
96: int i, j, len;
97:
98: printf("bp_op = ");
99: if (bp->bp_op == BOOTREQUEST) printf("BOOTREQUEST\n");
100: else if (bp->bp_op == BOOTREPLY) printf("BOOTREPLY\n");
101: else
102: {
103: i = bp->bp_op;
104: printf("%d\n", i);
105: }
106:
107: i = bp->bp_htype;
108: printf("bp_htype = %d\n", i);
109:
110: len = bp->bp_hlen;
111: printf("bp_hlen = %d\n", len);
112:
113: i = bp->bp_hops;
114: printf("bp_hops = %d\n", i);
115:
116: printf("bp_xid = %lu\n", bp->bp_xid);
117:
118: printf("bp_secs = %u\n", bp->bp_secs);
119:
120: printf("bp_ciaddr = " IP_FORMAT "\n", IP_LIST(&bp->bp_ciaddr));
121: printf("bp_yiaddr = " IP_FORMAT "\n", IP_LIST(&bp->bp_yiaddr));
122: printf("bp_siaddr = " IP_FORMAT "\n", IP_LIST(&bp->bp_siaddr));
123: printf("bp_giaddr = " IP_FORMAT "\n", IP_LIST(&bp->bp_giaddr));
124:
125: printf("bp_chaddr = ");
126: for (j = 0; j < len; j++)
127: {
128: i = bp->bp_chaddr[j];
129: printf("%0x", i);
130: if (j < (len - 1)) printf(":");
131: }
132: printf("\n");
133:
134: printf("bp_sname = %s\n", bp->bp_sname);
135: printf("bp_file = %s\n", bp->bp_file);
136: }
137:
138: static __inline__ void
139: print_reply_short(struct bootp *bp, int bp_len)
140: {
141: printf("bp_yiaddr = " IP_FORMAT "\n", IP_LIST(&bp->bp_yiaddr));
142: printf("bp_sname = %s\n", bp->bp_sname);
143: }
144:
145:
146: static __inline__ long
147: random_range(long bottom, long top)
148: {
149: long number = top - bottom + 1;
150: long range_size = LONG_MAX / number;
151: return (((long)random()) / range_size + bottom);
152: }
153:
154: /*
155: * Function: make_bootp_request
156: * Purpose:
157: * Create a "blank" bootp packet.
158: */
159: static void
160: make_bootp_request(struct bootp_packet * pkt,
161: u_char * hwaddr, u_char hwtype, u_char hwlen)
162: {
163: bzero(pkt, sizeof (*pkt));
164: pkt->bp_ip.ip_v = IPVERSION;
165: pkt->bp_ip.ip_hl = sizeof (struct ip) >> 2;
166: pkt->bp_ip.ip_id = htons(ip_id++);
167: pkt->bp_ip.ip_ttl = MAXTTL;
168: pkt->bp_ip.ip_p = IPPROTO_UDP;
169: pkt->bp_ip.ip_src.s_addr = 0;
170: pkt->bp_ip.ip_dst.s_addr = htonl(INADDR_BROADCAST);
171: pkt->bp_udp.uh_sport = htons(IPPORT_BOOTPC);
172: pkt->bp_udp.uh_dport = htons(IPPORT_BOOTPS);
173: pkt->bp_udp.uh_sum = 0;
174: pkt->bp_bootp.bp_op = BOOTREQUEST;
175: pkt->bp_bootp.bp_htype = hwtype;
176: pkt->bp_bootp.bp_hlen = hwlen;
177: pkt->bp_bootp.bp_ciaddr.s_addr = 0;
178: bcopy(hwaddr, pkt->bp_bootp.bp_chaddr, hwlen);
179: bcopy(rfc_magic, pkt->bp_bootp.bp_vend, sizeof(rfc_magic));
180: pkt->bp_bootp.bp_vend[4] = TAG_END;
181: pkt->bp_udp.uh_ulen = htons(sizeof(pkt->bp_udp) + sizeof(pkt->bp_bootp));
182: pkt->bp_ip.ip_len = htons(sizeof(struct ip) + ntohs(pkt->bp_udp.uh_ulen));
183: pkt->bp_ip.ip_sum = 0;
184: return;
185: }
186:
187: /*
188: * Function: ip_pkt_to_mbuf
189: * Purpose:
190: * Put the given IP packet into an mbuf, calculate the
191: * IP checksum.
192: */
193: struct mbuf *
194: ip_pkt_to_mbuf(caddr_t pkt, int pktsize)
195: {
196: struct ip * ip;
197: struct mbuf * m;
198:
199: m = (struct mbuf *)m_devget(pkt, pktsize, 0, 0, 0);
200: if (m == 0) {
201: printf("bootp: ip_pkt_to_mbuf: m_devget failed\n");
202: return 0;
203: }
204: m->m_flags |= M_BCAST;
205: /* Compute the checksum */
206: ip = mtod(m, struct ip *);
207: ip->ip_sum = 0;
208: ip->ip_sum = in_cksum(m, sizeof (struct ip));
209: return (m);
210: }
211:
212: static __inline__ u_char *
213: link_address(struct sockaddr_dl * dl_p)
214: {
215: return (dl_p->sdl_data + dl_p->sdl_nlen);
216: }
217:
218: static __inline__ void
219: link_print(struct sockaddr_dl * dl_p)
220: {
221: int i;
222:
223: #if 0
224: printf("len %d index %d family %d type 0x%x nlen %d alen %d"
225: " slen %d addr ", dl_p->sdl_len,
226: dl_p->sdl_index, dl_p->sdl_family, dl_p->sdl_type,
227: dl_p->sdl_nlen, dl_p->sdl_alen, dl_p->sdl_slen);
228: #endif 0
229: for (i = 0; i < dl_p->sdl_alen; i++)
230: printf("%s%x", i ? ":" : "",
231: (link_address(dl_p))[i]);
232: printf("\n");
233: return;
234: }
235:
236: static struct sockaddr_dl *
237: link_from_ifnet(struct ifnet * ifp)
238: {
239: struct ifaddr * addr;
240:
241: /* for (addr = ifp->if_addrlist; addr; addr = addr->ifa_next) */
242:
243: TAILQ_FOREACH(addr, &ifp->if_addrhead, ifa_link) {
244: if (addr->ifa_addr->sa_family == AF_LINK) {
245: struct sockaddr_dl * dl_p = (struct sockaddr_dl *)(addr->ifa_addr);
246:
247: return (dl_p);
248: }
249: }
250: return (NULL);
251: }
252:
253: /*
254: * Function: send_bootp_request
255: * Purpose:
256: * Send the request by calling the interface's output routine
257: * bypassing routing code.
258: */
259: static int
260: send_bootp_request(struct ifnet * ifp, struct socket * so,
261: struct bootp_packet * pkt)
262: {
263: struct mbuf * m;
264: struct sockaddr_in sin;
265:
266: /* Address to send to */
267: sin = blank_sin;
268: sin.sin_port = htons(IPPORT_BOOTPS);
269: sin.sin_addr.s_addr = INADDR_BROADCAST;
270:
271: m = ip_pkt_to_mbuf((caddr_t)pkt, sizeof(*pkt));
272: return (dlil_output((u_long) ifp, m, 0, (struct sockaddr *)&sin, 0));
273: }
274:
275: /*
276: * Function: receive_packet
277: * Purpose:
278: * Return a received packet or an error if none available.
279: */
280: int
281: receive_packet(struct socket * so, caddr_t pp, int psize)
282: {
283: struct iovec aiov;
284: struct uio auio;
285: int rcvflg;
286: int error;
287:
288: aiov.iov_base = pp;
289: aiov.iov_len = psize;
290: auio.uio_iov = &aiov;
291: auio.uio_iovcnt = 1;
292: auio.uio_segflg = UIO_SYSSPACE;
293: auio.uio_offset = 0;
294: auio.uio_resid = psize;
295: auio.uio_rw = UIO_READ;
296: rcvflg = MSG_WAITALL;
297:
298: error = soreceive(so, (struct sockaddr **) 0, &auio, 0, 0, &rcvflg);
299: return (error);
300: }
301:
302: /*
303: * Function: bootp_timeout
304: * Purpose:
305: * Wakeup the process waiting for something on a socket.
306: */
307: static void
308: bootp_timeout(struct socket * * socketflag)
309: {
310: struct socket * so = *socketflag;
311:
312: dprintf(("bootp: timeout\n"));
313:
314: *socketflag = NULL;
315: sowakeup(so, &so->so_rcv);
316: return;
317: }
318:
319: #define TAG_OFFSET 0
320: #define LEN_OFFSET 1
321: #define OPTION_OFFSET 2
322:
323: void *
324: packet_option(struct bootp * pkt, u_char t)
325: {
326: void * buffer = pkt->bp_vend + sizeof(rfc_magic);
327: int len;
328: unsigned char option_len;
329: void * ret = NULL;
330: unsigned char * scan;
331: unsigned char tag = TAG_PAD;
332:
333: len = sizeof(pkt->bp_vend) - sizeof(rfc_magic);
334: for (scan = buffer; len > 0; ) {
335: tag = scan[TAG_OFFSET];
336: if (tag == TAG_END) /* we hit the end of the options */
337: break;
338: if (tag == TAG_PAD) { /* discard pad characters */
339: scan++;
340: len--;
341: }
342: else {
343: if (t == tag && ret == NULL)
344: ret = scan + OPTION_OFFSET;
345: option_len = scan[LEN_OFFSET];
346: len -= (option_len + 2);
347: scan += (option_len + 2);
348: }
349: }
350: if (len < 0 || tag != TAG_END) { /* we ran off the end */
351: if (len < 0) {
352: dprintf(("bootp: error parsing options\n"));
353: }
354: else {
355: dprintf(("bootp: end tag missing\n"));
356: }
357: ret = NULL;
358: }
359: return (ret);
360: }
361:
362: /*
363: * Function: rate_packet
364: * Purpose:
365: * Return an integer point rating value for the given bootp packet.
366: * If yiaddr non-zero, the packet gets a rating of 1.
367: * Another point is given if the packet contains the subnet mask,
368: * and another if the router is present.
369: */
370: #define GOOD_RATING 3
371: static __inline__ int
372: rate_packet(struct bootp * pkt)
373: {
374: int rating = 0;
375:
376: if (pkt->bp_yiaddr.s_addr) {
377: struct in_addr * ip;
378:
379: rating++;
380: ip = (struct in_addr *)packet_option(pkt, TAG_SUBNET_MASK);
381: if (ip)
382: rating++;
383: ip = (struct in_addr *)packet_option(pkt, TAG_ROUTER);
384: if (ip)
385: rating++;
386: }
387: return (rating);
388: }
389:
390: #define INITIAL_WAIT_SECS 4
391: #define MAX_WAIT_SECS 64
392: #define GATHER_TIME_SECS 2
393: #define RAND_TICKS (hz) /* one second */
394:
395: /*
396: * Function: bootp_loop
397: * Purpose:
398: * Do the actual BOOTP protocol.
399: * The algorithm sends out a packet, waits for a response.
400: * We try max_try times, waiting in an exponentially increasing
401: * amount of time. Once we receive a good response, we start
402: * a new time period called the "gather time", during which we
403: * either find the perfect packet (one that has ip, mask and router)
404: * or we continue to gather responses. At the end of the gather period,
405: * we use the best response gathered.
406: */
407: static int
408: bootp_loop(struct socket * so, struct ifnet * ifp, int max_try,
409: struct in_addr * iaddr_p, struct in_addr * netmask_p,
410: struct in_addr * router_p)
411: {
412: struct timeval current_time;
413: struct sockaddr_dl * dl_p;
414: int error = 0;
415: char * hwaddr;
416: int hwlen;
417: char hwtype = 0;
418: struct bootp_packet * request = NULL;
419: struct bootp * reply = NULL;
420: struct bootp * saved_reply = NULL;
421: struct timeval start_time;
422: u_long xid;
423: int retry;
424: struct socket * timeflag;
425: int wait_ticks = INITIAL_WAIT_SECS * hz;
426:
427: /* get the hardware address from the interface */
428: dl_p = link_from_ifnet(ifp);
429: if (dl_p == NULL) {
430: printf("bootp: can't get link address\n");
431: return (ENXIO);
432: }
433:
434: printf("bootp: h/w addr ");
435: link_print(dl_p);
436:
437: hwaddr = link_address(dl_p);
438: hwlen = dl_p->sdl_alen;
439: switch (dl_p->sdl_type) {
440: case IFT_ETHER:
441: hwtype = ARPHRD_ETHER;
442: break;
443: default:
444: printf("bootp: hardware type %d not supported\n",
445: dl_p->sdl_type);
446: panic("bootp: hardware type not supported");
447: break;
448: }
449:
450: /* set transaction id and remember the start time */
451: microtime(&start_time);
452: current_time = start_time;
453: xid = random();
454:
455: /* make a request/reply packet */
456: request = (struct bootp_packet *)kalloc(sizeof(*request));
457: make_bootp_request(request, hwaddr, hwtype, hwlen);
458: reply = (struct bootp *)kalloc(sizeof(*reply));
459: saved_reply = (struct bootp *)kalloc(sizeof(*saved_reply));
460: iaddr_p->s_addr = 0;
461: printf("bootp: sending request");
462: for (retry = 0; retry < max_try; retry++) {
463: int gather_count = 0;
464: int last_rating = 0;
465:
466: /* Send the request */
467: printf(".");
468: request->bp_bootp.bp_secs = htons((u_short)(current_time.tv_sec
469: - start_time.tv_sec));
470: request->bp_bootp.bp_xid = htonl(xid);
471: error = send_bootp_request(ifp, so, request);
472: if (error)
473: goto cleanup;
474:
475: timeflag = so;
476: wait_ticks += random_range(-RAND_TICKS, RAND_TICKS);
477: dprintf(("bootp: waiting %d ticks\n", wait_ticks));
478: timeout(bootp_timeout, &timeflag, wait_ticks);
479:
480: while (TRUE) {
481: error = receive_packet(so, (caddr_t)reply, sizeof(*reply));
482: if (error == 0) {
483: dprintf(("\nbootp: received packet\n"));
484: if (ntohl(reply->bp_xid) == xid
485: && reply->bp_yiaddr.s_addr
486: && bcmp(reply->bp_chaddr, hwaddr, hwlen) == 0) {
487: int rating;
488: #ifdef BOOTP_DEBUG
489: print_reply_short(reply, sizeof(*reply));
490: #endif BOOTP_DEBUG
491: rating = rate_packet(reply);
492: if (rating > last_rating)
493: *saved_reply = *reply;
494: if (rating >= GOOD_RATING) {
495: untimeout(bootp_timeout, &timeflag);
496: goto save_values;
497: }
498: if (gather_count == 0) {
499: untimeout(bootp_timeout, &timeflag);
500: timeflag = so;
501: timeout(bootp_timeout, &timeflag,
502: hz * GATHER_TIME_SECS);
503: }
504: gather_count++;
505: }
506: else {
507: dprintf(("bootp: packet ignored\n"));
508: }
509: }
510: else if ((error != EWOULDBLOCK)) {
511: break;
512: }
513: else if (timeflag == NULL) { /* timed out */
514: if (gather_count) {
515: dprintf(("bootp: gathering time has expired"));
516: goto save_values; /* we have a packet */
517: }
518: break; /* retry */
519: }
520: else
521: sbwait(&so->so_rcv);
522: }
523: if (error && (error != EWOULDBLOCK)) {
524: dprintf(("bootp: failed to receive packets: %d\n", error));
525: untimeout(bootp_timeout, &timeflag);
526: goto cleanup;
527: }
528: wait_ticks *= 2;
529: if (wait_ticks > (MAX_WAIT_SECS * hz))
530: wait_ticks = MAX_WAIT_SECS * hz;
531: xid++;
532: microtime(¤t_time);
533: }
534: error = ETIMEDOUT;
535: goto cleanup;
536:
537: save_values:
538: error = 0;
539: printf("\nbootp: got response from %s (" IP_FORMAT ")\n",
540: saved_reply->bp_sname, IP_LIST(&saved_reply->bp_siaddr));
541: /* return the ip address */
542: *iaddr_p = saved_reply->bp_yiaddr;
543: {
544: struct in_addr * ip;
545: ip = (struct in_addr *)packet_option(saved_reply, TAG_SUBNET_MASK);
546: if (ip)
547: *netmask_p = *ip;
548: ip = (struct in_addr *)packet_option(saved_reply, TAG_ROUTER);
549: if (ip)
550: *router_p = *ip;
551: }
552:
553: cleanup:
554: if (request)
555: kfree((caddr_t)request, sizeof (*request));
556: if (reply)
557: kfree((caddr_t)reply, sizeof(*reply));
558: if (saved_reply)
559: kfree((caddr_t)saved_reply, sizeof(*saved_reply));
560: return (error);
561: }
562:
563: /*
564: * Routine: bootp
565: * Function:
566: * Use the BOOTP protocol to resolve what our IP address should be
567: * on a particular interface.
568: */
569: int bootp(struct ifnet * ifp, struct in_addr * iaddr_p, int max_try,
570: struct in_addr * netmask_p, struct in_addr * router_p,
571: struct proc * procp)
572: {
573: boolean_t addr_set = FALSE;
574: struct ifreq ifr;
575: int error;
576: struct socket * so = NULL;
577:
578: /* get a socket */
579: error = socreate(AF_INET, &so, SOCK_DGRAM, 0);
580: if (error) {
581: dprintf(("bootp: socreate failed %d\n", error));
582: return (error);
583: }
584:
585: /* assign the all-zeroes address */
586: bzero(&ifr, sizeof(ifr));
587: sprintf(ifr.ifr_name, "%s%d", ifp->if_name, ifp->if_unit);
588: *((struct sockaddr_in *)&ifr.ifr_addr) = blank_sin;
589: error = ifioctl(so, SIOCSIFADDR, (caddr_t)&ifr, procp);
590: if (error) {
591: dprintf(("bootp: SIOCSIFADDR all-zeroes IP failed: %d\n",
592: error));
593: goto cleanup;
594: }
595: dprintf(("bootp: all-zeroes IP address assigned\n"));
596: addr_set = TRUE;
597:
598: { /* bind the socket */
599: struct sockaddr_in * sin;
600:
601: sin = _MALLOC(sizeof(struct sockaddr_in), M_IFADDR, M_NOWAIT);
602: sin->sin_len = sizeof(struct sockaddr_in);
603: sin->sin_family = AF_INET;
604: sin->sin_port = htons(IPPORT_BOOTPC);
605: sin->sin_addr.s_addr = INADDR_ANY;
606: error = sobind(so, (struct sockaddr *) sin);
607:
608: FREE(sin, M_IFADDR);
609: if (error) {
610: dprintf(("bootp: sobind failed, %d\n", error));
611: goto cleanup;
612: }
613: so->so_state |= SS_NBIO;
614: }
615: /* do the protocol */
616: error = bootp_loop(so, ifp, max_try, iaddr_p, netmask_p, router_p);
617:
618: cleanup:
619: if (so) {
620: if (addr_set) {
621: (void) ifioctl(so, SIOCDIFADDR, (caddr_t) &ifr, procp);
622: }
623: soclose(so);
624: }
625: return (error);
626: }
627:
628: /*
629: * Function: in_bootp
630: * Purpose:
631: * This is deprecated API. Once SIOCAUTOADDR is eliminated from
632: * the system (IOEthernet class as well), this routine can be removed.
633: */
634: int
635: in_bootp(struct ifnet * ifp, struct sockaddr_in * sin, u_char my_enaddr[6])
636: {
637: return (EOPNOTSUPP);
638: }
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