xref: /openbsd/usr.sbin/tcpdump/print-bootp.c (revision 5dea098c)
1 /*	$OpenBSD: print-bootp.c,v 1.25 2021/12/01 18:28:45 deraadt Exp $	*/
2 
3 /*
4  * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that: (1) source code distributions
9  * retain the above copyright notice and this paragraph in its entirety, (2)
10  * distributions including binary code include the above copyright notice and
11  * this paragraph in its entirety in the documentation or other materials
12  * provided with the distribution, and (3) all advertising materials mentioning
13  * features or use of this software display the following acknowledgement:
14  * ``This product includes software developed by the University of California,
15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16  * the University nor the names of its contributors may be used to endorse
17  * or promote products derived from this software without specific prior
18  * written permission.
19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22  *
23  * Format and print bootp packets.
24  */
25 #include <sys/time.h>
26 #include <sys/socket.h>
27 
28 #include <net/if.h>
29 
30 #include <netinet/in.h>
31 #include <netinet/if_ether.h>
32 
33 #include <ctype.h>
34 #include <stdio.h>
35 #include <string.h>
36 
37 #include "interface.h"
38 #include "addrtoname.h"
39 #include "bootp.h"
40 
41 static void rfc1048_print(const u_char *, u_int);
42 static void cmu_print(const u_char *, u_int);
43 
44 static char tstr[] = " [|bootp]";
45 
46 /*
47  * Print bootp requests
48  */
49 void
50 bootp_print(const u_char *cp, u_int length,
51 	    u_short sport, u_short dport)
52 {
53 	const struct bootp *bp;
54 	static u_char vm_cmu[4] = VM_CMU;
55 	static u_char vm_rfc1048[4] = VM_RFC1048;
56 
57 	bp = (struct bootp *)cp;
58 	TCHECK(bp->bp_op);
59 	switch (bp->bp_op) {
60 
61 	case BOOTREQUEST:
62 		/* Usually, a request goes from a client to a server */
63 		if (sport != IPPORT_BOOTPC || dport != IPPORT_BOOTPS)
64 			printf("(request)");
65 		break;
66 
67 	case BOOTREPLY:
68 		/* Usually, a reply goes from a server to a client */
69 		if (sport != IPPORT_BOOTPS || dport != IPPORT_BOOTPC)
70 			printf("(reply)");
71 		break;
72 
73 	default:
74 		printf("bootp-#%d", bp->bp_op);
75 	}
76 
77 	TCHECK(bp->bp_flags);
78 
79 	/* The usual hardware address type is 1 (10Mb Ethernet) */
80 	if (bp->bp_htype != 1)
81 		printf(" htype-#%d", bp->bp_htype);
82 
83 	/* The usual length for 10Mb Ethernet address is 6 bytes */
84 	if (bp->bp_htype != 1 || bp->bp_hlen != 6)
85 		printf(" hlen:%d", bp->bp_hlen);
86 
87 	/* Only print interesting fields */
88 	if (bp->bp_hops)
89 		printf(" hops:%d", bp->bp_hops);
90 	if (bp->bp_xid)
91 		printf(" xid:0x%x", (u_int32_t)ntohl(bp->bp_xid));
92 	if (bp->bp_secs)
93 		printf(" secs:%d", ntohs(bp->bp_secs));
94 	if (bp->bp_flags)
95 		printf(" flags:0x%x", ntohs(bp->bp_flags));
96 
97 	/* Client's ip address */
98 	TCHECK(bp->bp_ciaddr);
99 	if (bp->bp_ciaddr.s_addr)
100 		printf(" C:%s", ipaddr_string(&bp->bp_ciaddr));
101 
102 	/* 'your' ip address (bootp client) */
103 	TCHECK(bp->bp_yiaddr);
104 	if (bp->bp_yiaddr.s_addr)
105 		printf(" Y:%s", ipaddr_string(&bp->bp_yiaddr));
106 
107 	/* Server's ip address */
108 	TCHECK(bp->bp_siaddr);
109 	if (bp->bp_siaddr.s_addr)
110 		printf(" S:%s", ipaddr_string(&bp->bp_siaddr));
111 
112 	/* Gateway's ip address */
113 	TCHECK(bp->bp_giaddr);
114 	if (bp->bp_giaddr.s_addr)
115 		printf(" G:%s", ipaddr_string(&bp->bp_giaddr));
116 
117 	/* Client's Ethernet address */
118 	if (bp->bp_htype == 1 && bp->bp_hlen == 6) {
119 		const struct ether_header *eh;
120 		const char *e;
121 
122 		TCHECK2(bp->bp_chaddr[0], 6);
123 		eh = (struct ether_header *)packetp;
124 		if (bp->bp_op == BOOTREQUEST)
125 			e = (const char *)ESRC(eh);
126 		else if (bp->bp_op == BOOTREPLY)
127 			e = (const char *)EDST(eh);
128 		else
129 			e = NULL;
130 		if (e == 0 || memcmp((char *)bp->bp_chaddr, e, 6) != 0)
131 			printf(" ether %s", etheraddr_string(bp->bp_chaddr));
132 	}
133 
134 	TCHECK2(bp->bp_sname[0], 1);		/* check first char only */
135 	if (*bp->bp_sname) {
136 		printf(" sname \"");
137 		if (fn_print(bp->bp_sname, snapend)) {
138 			putchar('"');
139 			printf("%s", tstr + 1);
140 			return;
141 		}
142 		putchar('"');
143 	}
144 	TCHECK2(bp->bp_file[0], 1);		/* check first char only */
145 	if (*bp->bp_file) {
146 		printf(" file \"");
147 		if (fn_print(bp->bp_file, snapend)) {
148 			putchar('"');
149 			printf("%s", tstr + 1);
150 			return;
151 		}
152 		putchar('"');
153 	}
154 
155 	/* Decode the vendor buffer */
156 	TCHECK2(bp->bp_vend[0], sizeof(u_int32_t));
157 	length -= sizeof(*bp) - sizeof(bp->bp_vend);
158 	if (memcmp((char *)bp->bp_vend, (char *)vm_rfc1048,
159 		 sizeof(u_int32_t)) == 0)
160 		rfc1048_print(bp->bp_vend, length);
161 	else if (memcmp((char *)bp->bp_vend, (char *)vm_cmu,
162 		      sizeof(u_int32_t)) == 0)
163 		cmu_print(bp->bp_vend, length);
164 	else {
165 		u_int32_t ul;
166 
167 		memcpy((char *)&ul, (char *)bp->bp_vend, sizeof(ul));
168 		if (ul != 0)
169 			printf("vend-#0x%x", ul);
170 	}
171 
172 	return;
173 trunc:
174 	printf("%s", tstr);
175 }
176 
177 /* The first character specifies the format to print */
178 static struct tok tag2str[] = {
179 /* RFC1048 tags */
180 	{ TAG_PAD,		" PAD" },
181 	{ TAG_SUBNET_MASK,	"iSM" },	/* subnet mask (RFC950) */
182 	{ TAG_TIME_OFFSET,	"lTZ" },	/* seconds from UTC */
183 	{ TAG_GATEWAY,		"iDG" },	/* default gateway */
184 	{ TAG_TIME_SERVER,	"iTS" },	/* time servers (RFC868) */
185 	{ TAG_NAME_SERVER,	"iIEN" },	/* IEN name servers (IEN116) */
186 	{ TAG_DOMAIN_SERVER,	"iNS" },	/* domain name (RFC1035) */
187 	{ TAG_LOG_SERVER,	"iLOG" },	/* MIT log servers */
188 	{ TAG_COOKIE_SERVER,	"iCS" },	/* cookie servers (RFC865) */
189 	{ TAG_LPR_SERVER,	"iLPR" },	/* lpr server (RFC1179) */
190 	{ TAG_IMPRESS_SERVER,	"iIM" },	/* impress servers (Imagen) */
191 	{ TAG_RLP_SERVER,	"iRL" },	/* resource location (RFC887) */
192 	{ TAG_HOSTNAME,		"aHN" },	/* ascii hostname */
193 	{ TAG_BOOTSIZE,		"sBS" },	/* 512 byte blocks */
194 	{ TAG_END,		" END" },
195 /* RFC1497 tags */
196 	{ TAG_DUMPPATH,		"aDP" },
197 	{ TAG_DOMAINNAME,	"aDN" },
198 	{ TAG_SWAP_SERVER,	"iSS" },
199 	{ TAG_ROOTPATH,		"aRP" },
200 	{ TAG_EXTPATH,		"aEP" },
201 /* RFC2132 tags */
202 	{ TAG_IP_FORWARD,	"BIPF" },
203 	{ TAG_NL_SRCRT,		"BSRT" },
204 	{ TAG_PFILTERS,		"pPF" },
205 	{ TAG_REASS_SIZE,	"sRSZ" },
206 	{ TAG_DEF_TTL,		"bTTL" },
207 	{ TAG_MTU_TIMEOUT,	"lMA" },
208 	{ TAG_MTU_TABLE,	"sMT" },
209 	{ TAG_INT_MTU,		"sMTU" },
210 	{ TAG_LOCAL_SUBNETS,	"BLSN" },
211 	{ TAG_BROAD_ADDR,	"iBR" },
212 	{ TAG_DO_MASK_DISC,	"BMD" },
213 	{ TAG_SUPPLY_MASK,	"BMS" },
214 	{ TAG_DO_RDISC,		"BRD" },
215 	{ TAG_RTR_SOL_ADDR,	"iRSA" },
216 	{ TAG_STATIC_ROUTE,	"pSR" },
217 	{ TAG_USE_TRAILERS,	"BUT" },
218 	{ TAG_ARP_TIMEOUT,	"lAT" },
219 	{ TAG_ETH_ENCAP,	"BIE" },
220 	{ TAG_TCP_TTL,		"bTT" },
221 	{ TAG_TCP_KEEPALIVE,	"lKI" },
222 	{ TAG_KEEPALIVE_GO,	"BKG" },
223 	{ TAG_NIS_DOMAIN,	"aYD" },
224 	{ TAG_NIS_SERVERS,	"iYS" },
225 	{ TAG_NTP_SERVERS,	"iNTP" },
226 	{ TAG_VENDOR_OPTS,	"bVO" },
227 	{ TAG_NETBIOS_NS,	"iWNS" },
228 	{ TAG_NETBIOS_DDS,	"iWDD" },
229 	{ TAG_NETBIOS_NODE,	"bWNT" },
230 	{ TAG_NETBIOS_SCOPE,	"aWSC" },
231 	{ TAG_XWIN_FS,		"iXFS" },
232 	{ TAG_XWIN_DM,		"iXDM" },
233 	{ TAG_NIS_P_DOMAIN,	"sN+D" },
234 	{ TAG_NIS_P_SERVERS,	"iN+S" },
235 	{ TAG_MOBILE_HOME,	"iMH" },
236 	{ TAG_SMPT_SERVER,	"iSMTP" },
237 	{ TAG_POP3_SERVER,	"iPOP3" },
238 	{ TAG_NNTP_SERVER,	"iNNTP" },
239 	{ TAG_WWW_SERVER,	"iWWW" },
240 	{ TAG_FINGER_SERVER,	"iFG" },
241 	{ TAG_IRC_SERVER,	"iIRC" },
242 	{ TAG_STREETTALK_SRVR,	"iSTS" },
243 	{ TAG_STREETTALK_STDA,	"iSTDA" },
244 	{ TAG_REQUESTED_IP,	"iRQ" },
245 	{ TAG_IP_LEASE,		"lLT" },
246 	{ TAG_OPT_OVERLOAD,	"bOO" },
247 	{ TAG_TFTP_SERVER,	"aTFTP" },
248 	{ TAG_BOOTFILENAME,	"aBF" },
249 	{ TAG_DHCP_MESSAGE,	" DHCP" },
250 	{ TAG_SERVER_ID,	"iSID" },
251 	{ TAG_PARM_REQUEST,	"bPR" },
252 	{ TAG_MESSAGE,		"aMSG" },
253 	{ TAG_MAX_MSG_SIZE,	"sMSZ" },
254 	{ TAG_RENEWAL_TIME,	"lRN" },
255 	{ TAG_REBIND_TIME,	"lRB" },
256 	{ TAG_VENDOR_CLASS,	"bVC" },
257 	{ TAG_CLIENT_ID,	"bCID" },
258 	{ 0,			NULL }
259 };
260 
261 static void
262 rfc1048_print(const u_char *bp, u_int length)
263 {
264 	u_char tag;
265 	u_int len, size;
266 	const char *cp;
267 	u_char c;
268 	int first;
269 	u_int32_t ul;
270 	u_short us;
271 
272 	printf(" vend-rfc1048");
273 
274 	/* Step over magic cookie */
275 	bp += sizeof(int32_t);
276 
277 	/* Loop while we there is a tag left in the buffer */
278 	while (bp + 1 < snapend) {
279 		tag = *bp++;
280 		if (tag == TAG_PAD)
281 			continue;
282 		if (tag == TAG_END)
283 			return;
284 		cp = tok2str(tag2str, "?T%d", tag);
285 		c = *cp++;
286 		printf(" %s:", cp);
287 
288 		/* Get the length; check for truncation */
289 		if (bp + 1 >= snapend) {
290 			printf("%s", tstr);
291 			return;
292 		}
293 		len = *bp++;
294 		if (bp + len >= snapend) {
295 			printf("%s", tstr);
296 			return;
297 		}
298 
299 		if (tag == TAG_DHCP_MESSAGE && len == 1) {
300 			c = *bp++;
301 			switch (c) {
302 			case DHCPDISCOVER:	printf("DISCOVER");	break;
303 			case DHCPOFFER:		printf("OFFER");	break;
304 			case DHCPREQUEST:	printf("REQUEST");	break;
305 			case DHCPDECLINE:	printf("DECLINE");	break;
306 			case DHCPACK:		printf("ACK");		break;
307 			case DHCPNAK:		printf("NACK");		break;
308 			case DHCPRELEASE:	printf("RELEASE");	break;
309 			case DHCPINFORM:	printf("INFORM");	break;
310 			default:		printf("%u", c);	break;
311 			}
312 			continue;
313 		}
314 
315 		if (tag == TAG_PARM_REQUEST) {
316 			first = 1;
317 			while (len-- > 0) {
318 				c = *bp++;
319 				cp = tok2str(tag2str, "?%d", c);
320 				if (!first)
321 					putchar('+');
322 				printf("%s", cp + 1);
323 				first = 0;
324 			}
325 			continue;
326 		}
327 
328 		/* Print data */
329 		size = len;
330 		if (c == '?') {
331 			/* Base default formats for unknown tags on data size */
332 			if (size & 1)
333 				c = 'b';
334 			else if (size & 2)
335 				c = 's';
336 			else
337 				c = 'l';
338 		}
339 		first = 1;
340 		switch (c) {
341 
342 		case 'a':
343 			/* ascii strings */
344 			putchar('"');
345 			(void)fn_printn(bp, size, NULL);
346 			putchar('"');
347 			bp += size;
348 			size = 0;
349 			break;
350 
351 		case 'i':
352 		case 'l':
353 			/* ip addresses/32-bit words */
354 			while (size >= sizeof(ul)) {
355 				if (!first)
356 					putchar(',');
357 				memcpy((char *)&ul, (char *)bp, sizeof(ul));
358 				if (c == 'i')
359 					printf("%s", ipaddr_string(&ul));
360 				else
361 					printf("%u", ntohl(ul));
362 				bp += sizeof(ul);
363 				size -= sizeof(ul);
364 				first = 0;
365 			}
366 			break;
367 
368 		case 'p':
369 			/* IP address pairs */
370 			while (size >= 2*sizeof(ul)) {
371 				if (!first)
372 					putchar(',');
373 				memcpy((char *)&ul, (char *)bp, sizeof(ul));
374 				printf("(%s:", ipaddr_string(&ul));
375 				bp += sizeof(ul);
376 				memcpy((char *)&ul, (char *)bp, sizeof(ul));
377 				printf("%s)", ipaddr_string(&ul));
378 				bp += sizeof(ul);
379 				size -= 2*sizeof(ul);
380 				first = 0;
381 			}
382 			break;
383 
384 		case 's':
385 			/* shorts */
386 			while (size >= sizeof(us)) {
387 				if (!first)
388 					putchar(',');
389 				memcpy((char *)&us, (char *)bp, sizeof(us));
390 				printf("%u", ntohs(us));
391 				bp += sizeof(us);
392 				size -= sizeof(us);
393 				first = 0;
394 			}
395 			break;
396 
397 		case 'B':
398 			/* boolean */
399 			while (size > 0) {
400 				if (!first)
401 					putchar(',');
402 				switch (*bp) {
403 				case 0:
404 					putchar('N');
405 					break;
406 				case 1:
407 					putchar('Y');
408 					break;
409 				default:
410 					printf("%d?", *bp);
411 					break;
412 				}
413 				++bp;
414 				--size;
415 				first = 0;
416 			}
417 			break;
418 
419 		case 'b':
420 		default:
421 			/* Bytes */
422 			while (size > 0) {
423 				if (!first)
424 					putchar('.');
425 				printf("%d", *bp);
426 				++bp;
427 				--size;
428 				first = 0;
429 			}
430 			break;
431 		}
432 		/* Data left over? */
433 		if (size)
434 			printf("[len %d]", len);
435 	}
436 }
437 
438 static void
439 cmu_print(const u_char *bp, u_int length)
440 {
441 	const struct cmu_vend *cmu;
442 	static const char fmt[] = " %s:%s";
443 
444 #define PRINTCMUADDR(m, s) { TCHECK(cmu->m); \
445     if (cmu->m.s_addr != 0) \
446 	printf(fmt, s, ipaddr_string(&cmu->m.s_addr)); }
447 
448 	printf(" vend-cmu");
449 	cmu = (struct cmu_vend *)bp;
450 
451 	/* Only print if there are unknown bits */
452 	TCHECK(cmu->v_flags);
453 	if ((cmu->v_flags & ~(VF_SMASK)) != 0)
454 		printf(" F:0x%x", cmu->v_flags);
455 	PRINTCMUADDR(v_dgate, "DG");
456 	PRINTCMUADDR(v_smask, cmu->v_flags & VF_SMASK ? "SM" : "SM*");
457 	PRINTCMUADDR(v_dns1, "NS1");
458 	PRINTCMUADDR(v_dns2, "NS2");
459 	PRINTCMUADDR(v_ins1, "IEN1");
460 	PRINTCMUADDR(v_ins2, "IEN2");
461 	PRINTCMUADDR(v_ts1, "TS1");
462 	PRINTCMUADDR(v_ts2, "TS2");
463 	return;
464 
465 trunc:
466 	printf("%s", tstr);
467 #undef PRINTCMUADDR
468 }
469