xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.sbin/snoop/snoop_dhcp.c (revision 66582b606a8194f7f3ba5b3a3a6dca5b0d346361)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <ctype.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <fcntl.h>
31 #include <string.h>
32 #include <sys/types.h>
33 #include <sys/socket.h>
34 #include <sys/sysmacros.h>
35 #include <netinet/in.h>
36 #include <netinet/dhcp.h>
37 #include <arpa/inet.h>
38 #include <dhcp_inittab.h>
39 #include <dhcp_symbol.h>
40 #include "snoop.h"
41 
42 static const char *show_msgtype(unsigned char);
43 static int show_options(unsigned char *, int);
44 static void display_ip(int, char *, char *, unsigned char **);
45 static void display_ascii(char *, char *, unsigned char **);
46 static void display_number(char *, char *, unsigned char **);
47 static void display_ascii_hex(char *, unsigned char **);
48 static unsigned char bootmagic[] = BOOTMAGIC;	/* rfc 1048 */
49 
50 static char *option_types[] = {
51 "",					/* 0 */
52 "Subnet Mask",				/* 1 */
53 "UTC Time Offset",			/* 2 */
54 "Router",				/* 3 */
55 "RFC868 Time Servers",			/* 4 */
56 "IEN 116 Name Servers",			/* 5 */
57 "DNS Servers",				/* 6 */
58 "UDP LOG Servers",			/* 7 */
59 "RFC 865 Cookie Servers",		/* 8 */
60 "RFC 1179 Line Printer Servers (LPR)",	/* 9 */
61 "Impress Servers",			/* 10 */
62 "RFC 887 Resource Location Servers",	/* 11 */
63 "Client Hostname",			/* 12 */
64 "Boot File size in 512 byte Blocks",	/* 13 */
65 "Merit Dump File",			/* 14 */
66 "DNS Domain Name",			/* 15 */
67 "SWAP Server",				/* 16 */
68 "Client Root Path",			/* 17 */
69 "BOOTP options extensions path",	/* 18 */
70 "IP Forwarding Flag",			/* 19 */
71 "NonLocal Source Routing Flag",		/* 20 */
72 "Policy Filters for NonLocal Routing",	/* 21 */
73 "Maximum Datagram Reassembly Size",	/* 22 */
74 "Default IP Time To Live",		/* 23 */
75 "Path MTU Aging Timeout",		/* 24 */
76 "Path MTU Size Plateau Table",		/* 25 */
77 "Interface MTU Size",			/* 26 */
78 "All Subnets are Local Flag",		/* 27 */
79 "Broadcast Address",			/* 28 */
80 "Perform Mask Discovery Flag",		/* 29 */
81 "Mask Supplier Flag",			/* 30 */
82 "Perform Router Discovery Flag",	/* 31 */
83 "Router Solicitation Address",		/* 32 */
84 "Static Routes",			/* 33 */
85 "Trailer Encapsulation Flag",		/* 34 */
86 "ARP Cache Timeout Seconds",		/* 35 */
87 "Ethernet Encapsulation Flag",		/* 36 */
88 "TCP Default Time To Live",		/* 37 */
89 "TCP Keepalive Interval Seconds",	/* 38 */
90 "TCP Keepalive Garbage Flag",		/* 39 */
91 "NIS Domainname",			/* 40 */
92 "NIS Servers",				/* 41 */
93 "Network Time Protocol Servers",	/* 42 */
94 "Vendor Specific Options",		/* 43 */
95 "NetBIOS RFC 1001/1002 Name Servers",	/* 44 */
96 "NetBIOS Datagram Dist. Servers",	/* 45 */
97 "NetBIOS Node Type",			/* 46 */
98 "NetBIOS Scope",			/* 47 */
99 "X Window Font Servers",		/* 48 */
100 "X Window Display Manager Servers",	/* 49 */
101 "Requested IP Address",			/* 50 */
102 "IP Address Lease Time",		/* 51 */
103 "Option Field Overload Flag",		/* 52 */
104 "DHCP Message Type",			/* 53 */
105 "DHCP Server Identifier",		/* 54 */
106 "Option Request List",			/* 55 */
107 "Error Message",			/* 56 */
108 "Maximum DHCP Message Size",		/* 57 */
109 "Renewal (T1) Time Value",		/* 58 */
110 "Rebinding (T2) Time Value",		/* 59 */
111 "Client Class Identifier =",		/* 60 */
112 "Client Identifier =",			/* 61 */
113 "Netware IP Domain =",			/* 62 */
114 "Netware IP Options =",			/* 63 */
115 "NIS+ v3 Client Domain Name =",		/* 64 */
116 "NIS+ v3 Server Addresses =",		/* 65 */
117 "TFTP Server Name",			/* 66 */
118 "Option BootFile Name",			/* 67 */
119 "Mobile IP Agents",			/* 68 */
120 "Simple Mail (SMTP) Servers",		/* 69 */
121 "Post Office (POP3) Servers",		/* 70 */
122 "Net News (NNTP) Servers",		/* 71 */
123 "WorldWideWeb Servers",			/* 72 */
124 "Finger Servers",			/* 73 */
125 "Internet Relay Chat (IRC) Servers",	/* 74 */
126 "StreetTalk Servers",			/* 75 */
127 "StreetTalk Directory Assist. Servers",	/* 76 */
128 "User Class Identifier",		/* 77 */
129 };
130 
131 #define	OPTIONS_ARRAY_SIZE	78
132 
133 int
134 interpret_dhcp(int flags, struct dhcp *dp, int len)
135 {
136 	if (flags & F_SUM) {
137 		if ((memcmp(dp->cookie, bootmagic, sizeof (bootmagic)) == 0) &&
138 		    (len >= BASE_PKT_SIZE + 3) &&
139 		    dp->options[0] == CD_DHCP_TYPE) {
140 			(void) sprintf(get_sum_line(),
141 			    "DHCP/BOOTP %s", show_msgtype(dp->options[2]));
142 		} else {
143 			switch (ntohs(dp->op)) {
144 			case BOOTREQUEST:
145 				(void) sprintf(get_sum_line(),
146 				    "DHCP/BOOTP BOOTREQUEST");
147 				break;
148 			case BOOTREPLY:
149 				(void) sprintf(get_sum_line(),
150 				    "DHCP/BOOTP BOOTREPLY");
151 				break;
152 			}
153 		}
154 	}
155 	if (flags & F_DTAIL) {
156 		show_header("DHCP: ", "Dynamic Host Configuration Protocol",
157 		    len);
158 		show_space();
159 		(void) sprintf(get_line((char *)(uintptr_t)dp->htype -
160 		    dlc_header, 1),
161 		    "Hardware address type (htype) =  %d (%s)", dp->htype,
162 		    arp_htype(dp->htype));
163 		(void) sprintf(get_line((char *)(uintptr_t)dp->hlen -
164 		    dlc_header, 1),
165 		    "Hardware address length (hlen) = %d octets", dp->hlen);
166 		(void) sprintf(get_line((char *)(uintptr_t)dp->hops -
167 		    dlc_header, 1),
168 		    "Relay agent hops = %d", dp->hops);
169 		(void) sprintf(get_line((char *)(uintptr_t)dp->xid -
170 		    dlc_header, 4),
171 		    "Transaction ID = 0x%x", ntohl(dp->xid));
172 		(void) sprintf(get_line((char *)(uintptr_t)dp->secs -
173 		    dlc_header, 2),
174 		    "Time since boot = %d seconds", ntohs(dp->secs));
175 		(void) sprintf(get_line((char *)(uintptr_t)dp->flags -
176 		    dlc_header, 2),
177 		    "Flags = 0x%.4x", ntohs(dp->flags));
178 		(void) sprintf(get_line((char *)&dp->ciaddr - dlc_header, 4),
179 		    "Client address (ciaddr) = %s", inet_ntoa(dp->ciaddr));
180 		(void) sprintf(get_line((char *)&dp->yiaddr - dlc_header, 4),
181 		    "Your client address (yiaddr) = %s",
182 		    inet_ntoa(dp->yiaddr));
183 		(void) sprintf(get_line((char *)&dp->siaddr - dlc_header, 4),
184 		    "Next server address (siaddr) = %s",
185 		    inet_ntoa(dp->siaddr));
186 		(void) sprintf(get_line((char *)&dp->giaddr - dlc_header, 4),
187 		    "Relay agent address (giaddr) = %s",
188 		    inet_ntoa(dp->giaddr));
189 		if (dp->htype == 1) {
190 			(void) sprintf(get_line((char *)dp->chaddr -
191 			    dlc_header, dp->hlen),
192 	"Client hardware address (chaddr) = %.2X:%.2X:%.2X:%.2X:%.2X:%.2X",
193 			    dp->chaddr[0],
194 			    dp->chaddr[1],
195 			    dp->chaddr[2],
196 			    dp->chaddr[3],
197 			    dp->chaddr[4],
198 			    dp->chaddr[5]);
199 		}
200 		/*
201 		 * Check cookie, process options
202 		 */
203 		if (memcmp(dp->cookie, bootmagic, sizeof (bootmagic)) != 0) {
204 			(void) sprintf(get_line(0, 0),
205 			    "Unrecognized cookie: 0x%.2X%.2X%.2X%.2X\n",
206 			    dp->cookie[0],
207 			    dp->cookie[1],
208 			    dp->cookie[2],
209 			    dp->cookie[3]);
210 			return (0);
211 		}
212 		show_space();
213 		show_header("DHCP: ", "(Options) field options", len);
214 		show_space();
215 		switch (show_options(dp->options, (len - BASE_PKT_SIZE))) {
216 		case 0:
217 			/* No option overloading */
218 			if (*(unsigned char *)(dp->sname) != '\0') {
219 				(void) sprintf(get_line(0, 0),
220 				    "Server Name = %s", dp->sname);
221 			}
222 			if (*(unsigned char *)(dp->file) != '\0') {
223 				(void) sprintf(get_line(0, 0),
224 				    "Boot File Name = %s", dp->file);
225 			}
226 			break;
227 		case 1:
228 			/* file field used */
229 			if (*(unsigned char *)(dp->sname) != '\0') {
230 				(void) sprintf(get_line(0, 0),
231 				    "Server Name = %s", dp->sname);
232 			}
233 			show_space();
234 			show_header("DHCP: ", "(File) field options", len);
235 			show_space();
236 			(void) show_options(dp->file, 128);
237 			break;
238 		case 2:
239 			/* sname field used for options */
240 			if (*(unsigned char *)(dp->file) != '\0') {
241 				(void) sprintf(get_line(0, 0),
242 				    "Boot File Name = %s", dp->file);
243 			}
244 			show_space();
245 			show_header("DHCP: ", "(Sname) field options", len);
246 			show_space();
247 			(void) show_options(dp->sname, 64);
248 			break;
249 		case 3:
250 			show_space();
251 			show_header("DHCP: ", "(File) field options", len);
252 			show_space();
253 			(void) show_options(dp->file, 128);
254 			show_space();
255 			show_header("DHCP: ", "(Sname) field options", len);
256 			show_space();
257 			(void) show_options(dp->sname, 64);
258 			break;
259 		};
260 	}
261 	return (len);
262 }
263 
264 static int
265 show_options(unsigned char  *cp, int len)
266 {
267 	char *prmpt;
268 	unsigned char *end, *vend;
269 	unsigned char *start, save;
270 	int items, i;
271 	int nooverload = 0;
272 	ushort_t	s_buf;
273 	struct in_addr	tmp;
274 	char scratch[128];
275 	dhcp_symbol_t *entry;
276 	char *decoded_opt;
277 	int opt_len;
278 
279 	start = cp;
280 	end = (unsigned char *)cp + len;
281 
282 	while (start < end) {
283 		if (*start == CD_PAD) {
284 			start++;
285 			continue;
286 		}
287 		if (*start == CD_END)
288 			break;	/* done */
289 
290 		save = *start++;
291 		switch (save) {
292 		/* Network order IP address(es) */
293 		case CD_SUBNETMASK:
294 		case CD_ROUTER_SOLICIT_SERV:
295 		case CD_BROADCASTADDR:
296 		case CD_REQUESTED_IP_ADDR:
297 		case CD_SERVER_ID:
298 			/* Single IP address */
299 			if (*start != 4) {
300 				(void) sprintf(get_line(0, 0),
301 				    "Error: Bad %s", option_types[save]);
302 			} else {
303 				start++;
304 				display_ip(1, "%s = %s", option_types[save],
305 				    &start);
306 			}
307 			break;
308 		case CD_ROUTER:
309 		case CD_TIMESERV:
310 		case CD_IEN116_NAME_SERV:
311 		case CD_DNSSERV:
312 		case CD_LOG_SERV:
313 		case CD_COOKIE_SERV:
314 		case CD_LPR_SERV:
315 		case CD_IMPRESS_SERV:
316 		case CD_RESOURCE_SERV:
317 		case CD_SWAP_SERV:
318 		case CD_NIS_SERV:
319 		case CD_NTP_SERV:
320 		case CD_NETBIOS_NAME_SERV:
321 		case CD_NETBIOS_DIST_SERV:
322 		case CD_XWIN_FONT_SERV:
323 		case CD_XWIN_DISP_SERV:
324 		case CD_MOBILE_IP_AGENT:
325 		case CD_SMTP_SERVS:
326 		case CD_POP3_SERVS:
327 		case CD_NNTP_SERVS:
328 		case CD_WWW_SERVS:
329 		case CD_FINGER_SERVS:
330 		case CD_IRC_SERVS:
331 		case CD_STREETTALK_SERVS:
332 		case CD_STREETTALK_DA_SERVS:
333 			/* Multiple IP addresses */
334 			if ((*start % 4) != 0) {
335 				(void) sprintf(get_line(0, 0),
336 				    "Error: Bad %s address",
337 				    option_types[save]);
338 			} else {
339 				items = *start++ / 4;
340 				display_ip(items, "%s at = %s",
341 				    option_types[save], &start);
342 			}
343 			break;
344 		case CD_TFTP_SERV_NAME:
345 		case CD_HOSTNAME:
346 		case CD_DUMP_FILE:
347 		case CD_DNSDOMAIN:
348 		case CD_ROOT_PATH:
349 		case CD_NIS_DOMAIN:
350 		case CD_NETBIOS_SCOPE:
351 		case CD_MESSAGE:
352 		case CD_OPT_BOOTFILE_NAME:
353 		case CD_USER_CLASS_ID:
354 			/* Ascii strings */
355 			display_ascii("%s = %s", option_types[save], &start);
356 			break;
357 		case CD_TIMEOFFSET:
358 		case CD_IPTTL:
359 		case CD_PATH_MTU_TIMEOUT:
360 		case CD_ARP_TIMEOUT:
361 		case CD_TCP_TTL:
362 		case CD_TCP_KALIVE_INTVL:
363 		case CD_T1_TIME:
364 		case CD_T2_TIME:
365 		case CD_LEASE_TIME:
366 			/* Number: seconds */
367 			display_number("%s = %d seconds", option_types[save],
368 			    &start);
369 			break;
370 		case CD_IP_FORWARDING_ON:
371 		case CD_NON_LCL_ROUTE_ON:
372 		case CD_ALL_SUBNETS_LCL_ON:
373 		case CD_MASK_DISCVRY_ON:
374 		case CD_MASK_SUPPLIER_ON:
375 		case CD_ROUTER_DISCVRY_ON:
376 		case CD_TRAILER_ENCAPS_ON:
377 		case CD_ETHERNET_ENCAPS_ON:
378 		case CD_TCP_KALIVE_GRBG_ON:
379 			/* Number:  hex flag */
380 			display_number("%s flag = 0x%x", option_types[save],
381 			    &start);
382 			break;
383 		case CD_MAXIPSIZE:
384 		case CD_MTU:
385 		case CD_MAX_DHCP_SIZE:
386 			/* Number: bytes */
387 			display_number("%s = %d bytes", option_types[save],
388 			    &start);
389 			break;
390 		case CD_CLASS_ID:
391 		case CD_CLIENT_ID:
392 		case CD_NW_IP_DOMAIN:
393 		case CD_NW_IP_OPTIONS:
394 			/* Hex ascii strings */
395 			display_ascii_hex(option_types[save], &start);
396 			break;
397 		case CD_BOOT_SIZE:
398 			display_number("%s = %d 512 byte blocks",
399 			    "Boot file size", &start);
400 			break;
401 		case CD_POLICY_FILTER:
402 			if ((*start % 8) != 0) {
403 				(void) sprintf(get_line(0, 0),
404 				    "Error: Bad Policy Filter option");
405 			} else {
406 				items = *start++ / 8;
407 				for (i = 0; i < items; i++) {
408 					display_ip(1,
409 					    "%s = %s",
410 					    "Policy Destination",
411 					    &start);
412 					display_ip(1, "%s = %s", "Mask",
413 					    &start);
414 				}
415 			}
416 			break;
417 		case CD_PATH_MTU_TABLE_SZ:
418 			if (*start % 2 != 0) {
419 				(void) sprintf(get_line(0, 0),
420 				    "Error: Bad Path MTU Table");
421 			} else {
422 				(void) sprintf(get_line(0, 0),
423 				    "\tPath MTU Plateau Table:");
424 				(void) sprintf(get_line(0, 0),
425 				    "\t=======================");
426 				items = *start / sizeof (ushort_t);
427 				++start;
428 				for (i = 0; i < items; i++) {
429 					if (IS_P2ALIGNED(start,
430 					    sizeof (ushort_t))) {
431 						/* LINTED: improper alignment */
432 						s_buf = *(ushort_t *)start;
433 					} else {
434 						memcpy((char *)&s_buf,
435 						    start, sizeof (short));
436 					}
437 					(void) sprintf(get_line(0, 0),
438 					    "\t\tEntry %d:\t\t%d", i,
439 					    ntohs(s_buf));
440 					start += sizeof (ushort_t);
441 				}
442 			}
443 			break;
444 		case CD_STATIC_ROUTE:
445 			if ((*start % 8) != 0) {
446 				(void) sprintf(get_line(0, 0),
447 				    "Error: Bad Static Route option: %d",
448 				    *start);
449 			} else {
450 				items = *start++ / 8;
451 				for (i = 0; i < items; i++) {
452 					memcpy((char *)&tmp, start,
453 					    sizeof (struct in_addr));
454 					(void) strcpy(scratch, inet_ntoa(tmp));
455 					start += sizeof (ulong_t);
456 					memcpy((char *)&tmp, start,
457 					    sizeof (struct in_addr));
458 					(void) sprintf(get_line(0, 0),
459 					    "Static route from %s to %s",
460 					    scratch, inet_ntoa(tmp));
461 					start += sizeof (ulong_t);
462 				}
463 			}
464 			break;
465 		case CD_VENDOR_SPEC:
466 			i = *start++;
467 			(void) sprintf(get_line(0, 0),
468 			    "Vendor-specific Options (%d total octets):", i);
469 			/*
470 			 * We don't know what these things are, so just
471 			 * display the option number, length, and value
472 			 * (hex).
473 			 */
474 			vend = (uchar_t *)((uchar_t *)start + i);
475 			while (start < vend && *start != CD_END) {
476 				if (*start == CD_PAD) {
477 					start++;
478 					continue;
479 				}
480 				(void) sprintf(scratch,
481 				    "\t(%.2d) %.2d octets", *start,
482 				    *(uchar_t *)((uchar_t *)start + 1));
483 				start++;
484 				display_ascii_hex(scratch, &start);
485 			}
486 			start = vend;	/* in case CD_END found */
487 			break;
488 		case CD_NETBIOS_NODE_TYPE:
489 			if (*start != 1) {
490 				(void) sprintf(get_line(0, 0),
491 				    "Error: Bad '%s' parameter",
492 				    option_types[CD_NETBIOS_NODE_TYPE]);
493 			} else {
494 				char *type;
495 				start++;
496 				switch (*start) {
497 				case 0x1:
498 					type = "Broadcast Node";
499 					break;
500 				case 0x2:
501 					type = "Point To Point Node";
502 					break;
503 				case 0x4:
504 					type = "Mixed Mode Node";
505 					break;
506 				case 0x8:
507 					type = "Hybrid Node";
508 					break;
509 				default:
510 					type = "??? Node";
511 					break;
512 				};
513 				(void) sprintf(get_line(0, 0),
514 				    "%s = %s (%d)",
515 				    option_types[CD_NETBIOS_NODE_TYPE],
516 				    type, *start);
517 				start++;
518 			}
519 			break;
520 		case CD_OPTION_OVERLOAD:
521 			if (*start != 1) {
522 				(void) sprintf(get_line(0, 0),
523 				    "Bad Option Overload value.");
524 			} else {
525 				start++;
526 				nooverload = *start++;
527 			}
528 			break;
529 		case CD_DHCP_TYPE:
530 			if (*start < 1 || *start > 7) {
531 				(void) sprintf(get_line(0, 0),
532 				    "Bad DHCP Message Type.");
533 			} else {
534 				start++;
535 				(void) sprintf(get_line(0, 0),
536 				    "Message type = %s",
537 				    show_msgtype(*start));
538 				start++;
539 			}
540 			break;
541 		case CD_REQUEST_LIST:
542 			opt_len = *start++;
543 			(void) sprintf(get_line(0, 0),
544 			    "Requested Options:");
545 			for (i = 0; i < opt_len; i++) {
546 				entry = NULL;
547 				if (*start < OPTIONS_ARRAY_SIZE) {
548 					prmpt = option_types[*start];
549 				} else {
550 					entry = inittab_getbycode(
551 					    ITAB_CAT_STANDARD|ITAB_CAT_SITE,
552 					    ITAB_CONS_SNOOP, *start);
553 					if (entry == NULL) {
554 						if (*start >= DHCP_SITE_OPT &&
555 						    *start <= DHCP_END_SITE) {
556 							prmpt = "Site Option";
557 						} else {
558 							prmpt = "Unrecognized "
559 							    "Option";
560 						}
561 					} else {
562 						prmpt = entry->ds_name;
563 					}
564 				}
565 				(void) sprintf(get_line(0, 0),
566 				    "\t%2d (%s)", *start, prmpt);
567 				start++;
568 				free(entry);
569 			}
570 			break;
571 		default:
572 			opt_len = *start++;
573 			entry = inittab_getbycode(
574 			    ITAB_CAT_STANDARD|ITAB_CAT_SITE,
575 			    ITAB_CONS_SNOOP, save);
576 			if (entry == NULL) {
577 				if (save >= DHCP_SITE_OPT &&
578 				    save <= DHCP_END_SITE)
579 					prmpt = "Site";
580 				else
581 					prmpt = "Unrecognized";
582 				decoded_opt = NULL;
583 			} else {
584 				if (save < OPTIONS_ARRAY_SIZE) {
585 					prmpt = option_types[save];
586 				} else {
587 					prmpt = entry->ds_name;
588 				}
589 				decoded_opt = inittab_decode(entry, start,
590 				    opt_len, B_TRUE);
591 			}
592 			if (decoded_opt == NULL) {
593 				(void) sprintf(get_line(0, 0),
594 				    "%s Option = %d, length = %d octets",
595 				    prmpt, save, opt_len);
596 				start--;
597 				display_ascii_hex("\tValue =", &start);
598 			} else {
599 				(void) sprintf(get_line(0, 0), "%s = %s", prmpt,
600 				    decoded_opt);
601 				start += opt_len;
602 				free(decoded_opt);
603 			}
604 			free(entry);
605 			break;
606 		};
607 	}
608 	return (nooverload);
609 }
610 
611 static const char *
612 show_msgtype(unsigned char type)
613 {
614 	/*
615 	 * note: the ordering here allows direct indexing of the table
616 	 *	 based on the RFC2131 packet type value passed in.
617 	 */
618 
619 	static const char *types[] = {
620 		"BOOTP",
621 		"DHCPDISCOVER", "DHCPOFFER",   "DHCPREQUEST", "DHCPDECLINE",
622 		"DHCPACK",    "DHCPNAK",      "DHCPRELEASE", "DHCPINFORM"
623 	};
624 
625 	if (type >= (sizeof (types) / sizeof (*types)) || types[type] == NULL)
626 		return ("UNKNOWN");
627 
628 	return (types[type]);
629 }
630 
631 static void
632 display_ip(int items, char *fmt, char *msg, unsigned char **opt)
633 {
634 	struct in_addr tmp;
635 	int i;
636 
637 	for (i = 0; i < items; i++) {
638 		memcpy((char *)&tmp, *opt, sizeof (struct in_addr));
639 		(void) sprintf(get_line(0, 0), fmt, msg, inet_ntoa(tmp));
640 		*opt += 4;
641 	}
642 }
643 
644 static void
645 display_ascii(char *fmt, char *msg, unsigned char **opt)
646 {
647 	static unsigned char buf[256];
648 	int len = **opt;
649 	unsigned char slen = len;
650 
651 	if (len >= sizeof (buf))
652 		len = sizeof (buf) - 1;
653 	(*opt)++;
654 	memcpy(buf, *opt, len);
655 	*(unsigned char *)(buf + len) = '\0';
656 	(void) sprintf(get_line(0, 0), fmt, msg, buf);
657 	(*opt) += slen;
658 }
659 
660 static void
661 display_number(char *fmt, char *msg, unsigned char **opt)
662 {
663 	int len = **opt;
664 	unsigned long l_buf = 0;
665 	unsigned short s_buf = 0;
666 
667 	if (len > 4) {
668 		(*opt)++;
669 		(void) sprintf(get_line(0, 0), fmt, msg, 0xdeadbeef);
670 		return;
671 	}
672 	switch (len) {
673 	case sizeof (uchar_t):
674 		(*opt)++;
675 		(void) sprintf(get_line(0, 0), fmt, msg, **opt);
676 		break;
677 	case sizeof (ushort_t):
678 		(*opt)++;
679 		if (IS_P2ALIGNED(*opt, sizeof (ushort_t)))
680 			/* LINTED: improper alignment */
681 			s_buf = *(unsigned short *)*opt;
682 		else
683 			memcpy((char *)&s_buf, *opt, len);
684 		(void) sprintf(get_line(0, 0), fmt, msg, ntohs(s_buf));
685 		break;
686 	case sizeof (ulong_t):
687 		(*opt)++;
688 		if (IS_P2ALIGNED(*opt, sizeof (ulong_t)))
689 			/* LINTED: improper alignment */
690 			l_buf = *(unsigned long *)*opt;
691 		else
692 			memcpy((char *)&l_buf, *opt, len);
693 		(void) sprintf(get_line(0, 0), fmt, msg, ntohl(l_buf));
694 		break;
695 	}
696 	(*opt) += len;
697 }
698 
699 static void
700 display_ascii_hex(char *msg, unsigned char **opt)
701 {
702 	int printable;
703 	char	buffer[512];
704 	char  *line, *tmp, *ap, *fmt;
705 	int	i, len = **opt;
706 
707 	line = get_line(0, 0);
708 
709 	(*opt)++;
710 
711 	if (len >= 255) {
712 		(void) sprintf(line, "\t%s <TOO LONG>", msg);
713 		return;
714 	}
715 
716 	for (printable = 1, tmp = (char *)(*opt), ap = buffer;
717 	    tmp < (char *)&((*opt)[len]); tmp++) {
718 		if (isprint(*tmp))
719 			*ap++ = *tmp;
720 		else {
721 			*ap++ = '.';
722 			printable = 0;
723 		}
724 	}
725 	*ap = '\0';
726 
727 	if (!printable) {
728 		for (tmp = (char *)(*opt), ap = buffer;
729 		    (tmp < (char *)&((*opt)[len])) && ((ap + 5) < &buffer[512]);
730 		    tmp++) {
731 			ap += sprintf(ap, "0x%02X ", *(uchar_t *)(tmp));
732 		}
733 		/* Truncate the trailing space */
734 		*(--ap) = '\0';
735 		/* More bytes to print in hex but no space in buffer */
736 		if (tmp < (char *)&((*opt)[len])) {
737 			i = ap - buffer;
738 			buffer[i - 1] = '.';
739 			buffer[i - 2] = '.';
740 			buffer[i - 3] = '.';
741 		}
742 		fmt = "%s\t%s (unprintable)";
743 	} else {
744 		fmt = "%s\t\"%s\"";
745 	}
746 	(*opt) += len;
747 	(void) sprintf(line, fmt, msg, buffer);
748 }
749