xref: /netbsd-src/sys/kern/uipc_mbufdebug.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /*	$NetBSD: uipc_mbufdebug.c,v 1.1 2018/07/17 05:52:07 msaitoh Exp $	*/
2 
3 /*
4  * Copyright (C) 2017 Internet Initiative Japan Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$SEIL: uipc_mbufseil.c$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/proc.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 
38 #include <net/if.h>
39 #include <net/if_ether.h>
40 #include <net/ppp_defs.h>
41 #include <net/if_arp.h>
42 
43 #include <netinet/in.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/ip.h>
46 #include <netinet/ip_icmp.h>
47 #include <netinet/ip6.h>
48 #include <netinet/icmp6.h>
49 #include <netinet/if_inarp.h>
50 #include <netinet/tcp.h>
51 #include <netinet/udp.h>
52 
53 #define EXAMINE_HEX_LIMIT 128
54 #define EXAMINE_HEX_COL 4
55 
56 /* mbuf operations without change of mbuf chain */
57 static int m_peek_data(const struct mbuf *, int, int, void *);
58 static unsigned int m_peek_len(const struct mbuf *, const char *);
59 
60 /* utility */
61 static char *str_ethaddr(const uint8_t *);
62 static char *str_ipaddr(const struct in_addr *);
63 static char *str_ip6addr(const struct in6_addr *);
64 static const char *str_ipproto(const uint8_t);
65 
66 /* parsers for m_examine() */
67 static void m_examine_ether(const struct mbuf *, int, const char *,
68     void (*)(const char *, ...));
69 static void m_examine_pppoe(const struct mbuf *, int, const char *,
70     void (*)(const char *, ...));
71 static void m_examine_ppp(const struct mbuf *, int, const char *,
72     void (*)(const char *, ...));
73 static void m_examine_arp(const struct mbuf *, int, const char *,
74     void (*)(const char *, ...));
75 static void m_examine_ip(const struct mbuf *, int, const char *,
76     void (*)(const char *, ...));
77 static void m_examine_icmp(const struct mbuf *, int, const char *,
78     void (*)(const char *, ...));
79 static void m_examine_ip6(const struct mbuf *, int, const char *,
80     void (*)(const char *, ...));
81 static void m_examine_icmp6(const struct mbuf *, int, const char *,
82     void (*)(const char *, ...));
83 static void m_examine_tcp(const struct mbuf *, int, const char *,
84     void (*)(const char *, ...));
85 static void m_examine_udp(const struct mbuf *, int, const char *,
86     void (*)(const char *, ...));
87 static void m_examine_hex(const struct mbuf *, int, const char *,
88     void (*)(const char *, ...));
89 
90 /* header structure for some protocol */
91 struct pppoehdr {
92 	uint8_t vertype;
93 	uint8_t code;
94 	uint16_t session;
95 	uint16_t plen;
96 } __attribute__((__packed__));
97 
98 struct pppoetag {
99 	uint16_t tag;
100 	uint16_t len;
101 } __attribute__((__packed__));
102 
103 #define PPPOE_TAG_EOL 0x0000
104 #define PPPOE_CODE_PADI		0x09	/* Active Discovery Initiation */
105 #define	PPPOE_CODE_PADO		0x07	/* Active Discovery Offer */
106 #define	PPPOE_CODE_PADR		0x19	/* Active Discovery Request */
107 #define	PPPOE_CODE_PADS		0x65	/* Active Discovery Session confirmation */
108 #define	PPPOE_CODE_PADT		0xA7	/* Active Discovery Terminate */
109 
110 struct ppp_header {
111 	uint8_t address;
112 	uint8_t control;
113 	uint16_t protocol;
114 } __attribute__((__packed__));
115 
116 #define CISCO_MULTICAST		0x8f	/* Cisco multicast address */
117 #define CISCO_UNICAST		0x0f	/* Cisco unicast address */
118 #define CISCO_KEEPALIVE		0x8035	/* Cisco keepalive protocol */
119 
120 #ifndef NELEMS
121 #define NELEMS(elem) ((sizeof(elem))/(sizeof((elem)[0])))
122 #endif
123 
124 static int
125 m_peek_data(const struct mbuf *m, int off, int len, void *vp)
126 {
127 	unsigned int count;
128 	char *cp = vp;
129 
130 	if (off < 0 || len < 0)
131 		return -1;
132 
133 	while (off > 0) {
134 		if (m == 0)
135 			return -1;
136 		if (off < m->m_len)
137 			break;
138 		off -= m->m_len;
139 		m = m->m_next;
140 	}
141 	while (len > 0) {
142 		if (m == 0)
143 			return -1;
144 		count = min(m->m_len - off, len);
145 		memcpy(cp, mtod(m, char *) + off, count);
146 		len -= count;
147 		cp += count;
148 		off = 0;
149 		m = m->m_next;
150 	}
151 
152 	return 0;
153 }
154 
155 static unsigned int
156 m_peek_len(const struct mbuf *m, const char *modif)
157 {
158 	const struct mbuf *m0;
159 	unsigned int pktlen;
160 	boolean_t opt_c = FALSE;
161 	unsigned char ch;
162 
163 	while ( modif && (ch = *(modif++)) != '\0') {
164 		switch (ch) {
165 		case 'c':
166 			opt_c = TRUE;
167 			break;
168 		}
169 	}
170 
171 	if (opt_c == TRUE) {
172 		return m->m_len;
173 	}
174 
175 	if ((m->m_flags & M_PKTHDR) != 0)
176 		return m->m_pkthdr.len;
177 
178 	pktlen = 0;
179 	for (m0 = m; m0 != NULL; m0 = m0->m_next)
180 		pktlen += m0->m_len;
181 
182 	return pktlen;
183 }
184 
185 static char *
186 str_ethaddr(const uint8_t *ap)
187 {
188 	static char buf[3 * ETHER_ADDR_LEN];
189 
190 	return ether_snprintf(buf, sizeof(buf), ap);
191 }
192 
193 static char *
194 str_ipaddr(const struct in_addr *ap)
195 {
196 	static char buf[INET_ADDRSTRLEN];
197 
198 	return IN_PRINT(buf, ap);
199 }
200 
201 static char *
202 str_ip6addr(const struct in6_addr *ap)
203 {
204 	static char buf[INET6_ADDRSTRLEN];
205 
206 	return IN6_PRINT(buf, ap);
207 }
208 
209 static const char *
210 str_ipproto(const uint8_t proto)
211 {
212 	switch (proto) {
213 	case IPPROTO_HOPOPTS:
214 		return ("IPv6 Hop-by-Hop");
215 		break;
216 	case IPPROTO_TCP:
217 		return("TCP");
218 		break;
219 	case IPPROTO_UDP:
220 		return("UDP");
221 		break;
222 	case IPPROTO_ICMP:
223 		return("ICMP");
224 		break;
225 	case IPPROTO_IGMP:
226 		return("IGMP");
227 		break;
228 	case IPPROTO_ESP:
229 		return("ESP");
230 		break;
231 	case IPPROTO_AH:
232 		return("AH");
233 		break;
234 	case IPPROTO_IPV6_ICMP:
235 		return("ICMP6");
236 	default:
237 		return("unknown");
238 		break;
239 	}
240 
241 	/* not reached */
242 	return NULL;
243 }
244 
245 static void
246 m_examine_ether(const struct mbuf *m, int off, const char *modif,
247     void (*pr)(const char *, ...))
248 {
249 	struct ether_header eh;
250 	unsigned int pktlen;
251 
252 	pktlen = m_peek_len(m, modif) - off;
253 	if (pktlen < sizeof(eh)) {
254 		(*pr)("%s: too short mbuf chain\n", __func__);
255 		return m_examine_hex(m, off, modif, pr);
256 	}
257 
258 	if (m_peek_data(m, off, sizeof(eh), (void *)(&eh)) < 0) {
259 		(*pr)("%s: cannot read header\n", __func__);
260 		return m_examine_hex(m, off, modif, pr);
261 	}
262 	off += sizeof(eh);
263 
264 	(*pr)("ETHER: DST = %s\n", str_ethaddr(eh.ether_dhost));
265 	(*pr)("ETHER: SRC = %s\n", str_ethaddr(eh.ether_shost));
266 
267 	(*pr)("ETHER: TYPE = 0x%04x(", ntohs(eh.ether_type));
268 	switch (ntohs(eh.ether_type)) {
269 	case ETHERTYPE_PPPOE:
270 		(*pr)("PPPoE)\n");
271 		return m_examine_pppoe(m, off, modif, pr);
272 		break;
273 	case ETHERTYPE_ARP:
274 		(*pr)("ARP)\n");
275 		return m_examine_arp(m, off, modif, pr);
276 		break;
277 	case ETHERTYPE_IP:
278 		(*pr)("IPv4)\n");
279 		return m_examine_ip(m, off, modif, pr);
280 		break;
281 	case ETHERTYPE_IPV6:
282 		(*pr)("IPv6)\n");
283 		return m_examine_ip6(m, off, modif, pr);
284 		break;
285 	default:
286 		(*pr)("unknown)\n");
287 		break;
288 	}
289 
290 	return m_examine_hex(m, off, modif, pr);
291 }
292 
293 static void
294 m_examine_pppoe(const struct mbuf *m, int off, const char *modif,
295     void (*pr)(const char *, ...))
296 {
297 	struct pppoehdr ph;
298 	struct pppoetag pt;
299 	unsigned int pktlen;
300 	uint8_t vt;
301 
302 	pktlen = m_peek_len(m, modif) - off;
303 	if (pktlen < sizeof(ph)) {
304 		(*pr)("%s: too short mbuf chain\n", __func__);
305 		return m_examine_hex(m, off, modif, pr);
306 	}
307 
308 	if (m_peek_data(m, off, sizeof(ph), (void *)(&ph)) < 0) {
309 		(*pr)("%s: cannot read header\n", __func__);
310 		return m_examine_hex(m, off, modif, pr);
311 	}
312 	off += sizeof(ph);
313 
314 	while (off + sizeof(pt) > pktlen) {
315 		if (m_peek_data(m, off, sizeof(pt), (void *)(&pt)) < 0) {
316 			(*pr)("%s: cannot read header\n", __func__);
317 			return m_examine_hex(m, off, modif, pr);
318 		}
319 		off += sizeof(pt);
320 
321 		if (ntohs(pt.tag) == PPPOE_TAG_EOL)
322 			break;
323 		off += ntohs(pt.len);
324 	}
325 
326 	vt = ph.vertype;
327 
328 	(*pr)("PPPoE: Version = %u\n", ((vt >> 4) & 0xff));
329 	(*pr)("PPPoE: Type = %u\n", (vt & 0xff));
330 	(*pr)("PPPoE: Code = %u(", ph.code);
331 	switch (ph.code) {
332 	case 0:
333 		(*pr)("DATA");
334 		break;
335 	case PPPOE_CODE_PADI:
336 		(*pr)("PADI");
337 		break;
338 	case PPPOE_CODE_PADO:
339 		(*pr)("PADO");
340 		break;
341 	case PPPOE_CODE_PADS:
342 		(*pr)("PADS");
343 		break;
344 	case PPPOE_CODE_PADT:
345 		(*pr)("PADT");
346 		break;
347 	default:
348 		(*pr)("unknown");
349 		break;
350 	}
351 	(*pr)(")\n");
352 
353 	(*pr)("PPPoE: Session = 0x%04x\n", ntohs(ph.session));
354 	(*pr)("PPPoE: Payload Length = %u\n", ntohs(ph.plen));
355 
356 	switch (ph.code) {
357 	case PPPOE_CODE_PADI:
358 	case PPPOE_CODE_PADO:
359 	case PPPOE_CODE_PADS:
360 	case PPPOE_CODE_PADT:
361 		(*pr)("No parser for PPPoE control frame.\n");
362 		return m_examine_hex(m, off, modif, pr);
363 		break;
364 	}
365 
366 	if (ph.code != 0) {
367 		(*pr)("Unknown PPPoE code.\n");
368 		return m_examine_hex(m, off, modif, pr);
369 	}
370 
371 	return m_examine_ppp(m, off, modif, pr);
372 }
373 
374 static void
375 m_examine_ppp(const struct mbuf *m, int off, const char *modif,
376     void (*pr)(const char *, ...))
377 {
378 	struct ppp_header h;
379 	unsigned int pktlen;
380 	uint16_t protocol;
381 
382 	pktlen = m_peek_len(m, modif) - off;
383 	if (pktlen < sizeof(h)) {
384 		(*pr)("%s: too short mbuf chain\n", __func__);
385 		return m_examine_hex(m, off, modif, pr);
386 	}
387 
388 	if (m_peek_data(m, off, sizeof(h), (void *)(&h)) < 0) {
389 		(*pr)("%s: cannot read header\n", __func__);
390 		return m_examine_hex(m, off, modif, pr);
391 	}
392 	off += sizeof(h);
393 
394 	protocol = ntohs(h.protocol);
395 
396 	(*pr)("SPPP: Address = %d(", h.address);
397 	switch (h.address) {
398 	case PPP_ALLSTATIONS:
399 		(*pr)("ALLSTATIONS)\n");
400 		(*pr)("SPPP: Protocol = %d(", protocol);
401 		switch (protocol) {
402 		case PPP_LCP:
403 			(*pr)("LCP)\n");
404 			break;
405 		case PPP_PAP:
406 			(*pr)("PAP)\n");
407 			break;
408 		case PPP_CHAP:
409 			(*pr)("CHAP)\n");
410 			break;
411 		case PPP_IPCP:
412 			(*pr)("IPCP)\n");
413 			break;
414 		case PPP_IPV6CP:
415 			(*pr)("IPV6CP)\n");
416 			break;
417 		case PPP_IP:
418 			(*pr)("IP)\n");
419 			return m_examine_ip(m, off, modif, pr);
420 			break;
421 		case PPP_IPV6:
422 			(*pr)("IPv6)\n");
423 			return m_examine_ip6(m, off, modif, pr);
424 			break;
425 		default:
426 			(*pr)("unknown)\n");
427 			break;
428 		}
429 		break;
430 	case CISCO_MULTICAST:
431 	case CISCO_UNICAST:
432 		if (h.address == CISCO_MULTICAST) {
433 			(*pr)("MULTICAST)\n");
434 		}
435 		else {
436 			(*pr)("UNICAST)\n");
437 		}
438 		(*pr)("SPPP: Protocol = %d(", protocol);
439 		switch (protocol) {
440 		case CISCO_KEEPALIVE:
441 			(*pr)("Keepalive)\n");
442 			break;
443 		case ETHERTYPE_IP:
444 			(*pr)("IP)\n");
445 			return m_examine_ip(m, off, modif, pr);
446 			break;
447 		case ETHERTYPE_IPV6:
448 			(*pr)("IPv6)\n");
449 			return m_examine_ip6(m, off, modif, pr);
450 			break;
451 		default:
452 			(*pr)("unknown)\n");
453 			break;
454 		}
455 		break;
456 	default:
457 		(*pr)("unknown)\n", h.address);
458 		break;
459 	}
460 
461 	(*pr)("No parser for address %d, protocol %d\n", h.address, protocol);
462 	return m_examine_hex(m, off, modif, pr);
463 }
464 
465 static void
466 m_examine_arp(const struct mbuf *m, int off, const char *modif,
467     void (*pr)(const char *, ...))
468 {
469 	unsigned int pktlen;
470 	struct arphdr ar;
471 	uint16_t hrd, op;
472 	struct in_addr isaddr, itaddr;
473 	uint8_t esaddr[ETHER_ADDR_LEN], etaddr[ETHER_ADDR_LEN];
474 
475 	pktlen = m_peek_len(m, modif) - off;
476 	if (pktlen < sizeof(ar)) {
477 		(*pr)("%s: too short mbuf chain\n", __func__);
478 		return m_examine_hex(m, off, modif, pr);
479 	}
480 
481 	if (m_peek_data(m, off, sizeof(ar), (void *)(&ar)) < 0) {
482 		(*pr)("%s: cannot read header\n", __func__);
483 		return m_examine_hex(m, off, modif, pr);
484 	}
485 	off += sizeof(ar);
486 
487 	hrd = ntohs(ar.ar_hrd);
488 	(*pr)("ARP: AddressType = %u(", hrd);
489 	switch (hrd) {
490 	case ARPHRD_ETHER:
491 		(*pr)("ETHER)\n");
492 		break;
493 	case ARPHRD_IEEE802:
494 		(*pr)("IEEE802)\n");
495 		break;
496 	default:
497 		(*pr)("unknown)\n");
498 		return m_examine_hex(m, off, modif, pr);
499 		break;
500 	}
501 	(*pr)("ARP: Protocol Address Format = %u\n", ntohs(ar.ar_pro));
502 	(*pr)("ARP: Protocol Address Length = %u\n", ar.ar_pln);
503 	(*pr)("ARP: H/W Address Length = %u\n", ar.ar_hln);
504 	op = ntohs(ar.ar_op);
505 	(*pr)("ARP: Operation = %u(", op);
506 	switch (op) {
507 	case ARPOP_REQUEST:
508 		(*pr)("REQUEST)\n");
509 		break;
510 	case ARPOP_REPLY:
511 		(*pr)("REPLY)\n");
512 		break;
513 	case ARPOP_REVREQUEST:
514 		(*pr)("REVREQUEST)\n");
515 		break;
516 	case ARPOP_REVREPLY:
517 		(*pr)("REVREPLY)\n");
518 		break;
519 	case ARPOP_INVREQUEST:
520 		(*pr)("INVREQUEST)\n");
521 		break;
522 	case ARPOP_INVREPLY:
523 		(*pr)("INVREPLY)\n");
524 		break;
525 	}
526 
527 	if (ar.ar_hln == 0 || ar.ar_pln == 0 ||
528 	    ar.ar_hln != sizeof(esaddr) || ar.ar_pln != sizeof(isaddr)) {
529 		(*pr)("Cannot parse.\n");
530 		return m_examine_hex(m, off, modif, pr);
531 	}
532 
533 	if (m_peek_data(m, off, sizeof(esaddr), (void *)(esaddr)) < 0) {
534 		(*pr)("Cannot read payload\n");
535 		return m_examine_hex(m, off, modif, pr);
536 	}
537 	off += sizeof(esaddr);
538 	(*pr)("ARP: Ether Src = %s\n", str_ethaddr(esaddr));
539 
540 	if (m_peek_data(m, off, sizeof(isaddr), (void *)(&isaddr)) < 0) {
541 		(*pr)("Cannot read payload\n");
542 		return m_examine_hex(m, off, modif, pr);
543 	}
544 	off += sizeof(isaddr);
545 	(*pr)("ARP: IP Src = %s\n", str_ipaddr(&isaddr));
546 
547 	if (m_peek_data(m, off, sizeof(etaddr), (void *)(etaddr)) < 0) {
548 		(*pr)("Cannot read payload\n");
549 		return m_examine_hex(m, off, modif, pr);
550 	}
551 	off += sizeof(etaddr);
552 	(*pr)("ARP: Ether Tgt = %s\n", str_ethaddr(etaddr));
553 
554 	if (m_peek_data(m, off, sizeof(itaddr), (void *)(&itaddr)) < 0) {
555 		(*pr)("Cannot read payload\n");
556 		return m_examine_hex(m, off, modif, pr);
557 	}
558 	off += sizeof(itaddr);
559 	(*pr)("ARP: IP Tgt = %s\n", str_ipaddr(&itaddr));
560 
561 	return m_examine_hex(m, off, modif, pr);
562 }
563 
564 static void
565 m_examine_ip(const struct mbuf *m, int off, const char *modif,
566     void (*pr)(const char *, ...))
567 {
568 	unsigned int pktlen;
569 	struct ip ip;
570 	uint16_t offset;
571 
572 	pktlen = m_peek_len(m, modif) - off;
573 	if (pktlen < sizeof(ip)) {
574 		(*pr)("%s: too short mbuf chain\n", __func__);
575 		return m_examine_hex(m, off, modif, pr);
576 	}
577 
578 	if (m_peek_data(m, off, sizeof(ip), (void *)(&ip)) < 0) {
579 		(*pr)("%s: cannot read header\n", __func__);
580 		return m_examine_hex(m, off, modif, pr);
581 	}
582 	off += sizeof(ip);
583 
584 	(*pr)("IP: Version = %u\n", ip.ip_v);
585 	(*pr)("IP: Header Length = %u\n", (ip.ip_hl << 2));
586 	(*pr)("IP: ToS = 0x%02x\n", ip.ip_tos);
587 	(*pr)("IP: Packet Length = %u\n", ntohs(ip.ip_len));
588 	(*pr)("IP: ID = %u\n", ntohs(ip.ip_id));
589 	offset = ntohs(ip.ip_off);
590 	(*pr)("IP: Offset = %u\n", (offset & IP_OFFMASK));
591 	if (offset & IP_RF) {
592 		(*pr)("IP: Flag 0x%04x (reserved)\n", IP_RF);
593 	}
594 	if (offset & IP_EF) {
595 		(*pr)("IP: Flag 0x%04x (evil flag)\n", IP_EF);
596 	}
597 	if (offset & IP_DF) {
598 		(*pr)("IP: Flag 0x%04x (don't fragment)\n", IP_DF);
599 	}
600 	if (offset & IP_MF) {
601 		(*pr)("IP: Flag 0x%04x (more fragment)\n", IP_MF);
602 	}
603 	(*pr)("IP: TTL = %u\n", ip.ip_ttl);
604 	(*pr)("IP: protocol = %u(%s)\n", ip.ip_p, str_ipproto(ip.ip_p));
605 	(*pr)("IP: Src = %s\n", str_ipaddr(&ip.ip_src));
606 	(*pr)("IP: Dst = %s\n", str_ipaddr(&ip.ip_dst));
607 
608 
609 	switch (ip.ip_p) {
610 	case IPPROTO_ICMP:
611 		return m_examine_icmp(m, off, modif, pr);
612 		break;
613 	case IPPROTO_TCP:
614 		return m_examine_tcp(m, off, modif, pr);
615 		break;
616 	case IPPROTO_UDP:
617 		return m_examine_udp(m, off, modif, pr);
618 		break;
619 	default:
620 		break;
621 	}
622 
623 
624 	return m_examine_hex(m, off, modif, pr);
625 }
626 
627 static void
628 m_examine_icmp(const struct mbuf *m, int off, const char *modif,
629     void (*pr)(const char *, ...))
630 {
631 	unsigned int pktlen;
632 	struct icmp icmphdr;
633 
634 	pktlen = m_peek_len(m, modif) - off;
635 	if (pktlen < sizeof(icmphdr)) {
636 		(*pr)("%s: too short mbuf chain\n", __func__);
637 		return m_examine_hex(m, off, modif, pr);
638 	}
639 
640 	if (m_peek_data(m, off, sizeof(icmphdr), (void *)(&icmphdr)) < 0) {
641 		(*pr)("%s: cannot read header\n", __func__);
642 		return m_examine_hex(m, off, modif, pr);
643 	}
644 	off += sizeof(icmphdr);
645 
646 	(*pr)("ICMP: Type = %u(", icmphdr.icmp_type);
647 	switch (icmphdr.icmp_type) {
648 	case ICMP_ECHOREPLY:
649 		(*pr)("Echo Reply)\n");
650 		break;
651 	case ICMP_UNREACH:
652 		(*pr)("Destination Unreachable)\n");
653 		break;
654 	case ICMP_SOURCEQUENCH:
655 		(*pr)("Source Quench)\n");
656 		break;
657 	case ICMP_REDIRECT:
658 		(*pr)("Redirect)\n");
659 		break;
660 	case ICMP_TIMXCEED:
661 		(*pr)("Time Exceeded)\n");
662 		break;
663 	default:
664 		(*pr)("unknown)\n");
665 		break;
666 	}
667 	(*pr)("ICMP: Code = %d\n", icmphdr.icmp_code);
668 
669 	return m_examine_hex(m, off, modif, pr);
670 }
671 
672 static void
673 m_examine_ip6(const struct mbuf *m, int off, const char *modif,
674     void (*pr)(const char *, ...))
675 {
676 	unsigned int pktlen;
677 	struct ip6_hdr ip6;
678 	struct ip6_hbh hbh;
679 	int hbhlen;
680 	uint32_t flow;
681 	uint8_t vfc;
682 	uint8_t nxt;
683 
684 	pktlen = m_peek_len(m, modif) - off;
685 	if (pktlen < sizeof(ip6)) {
686 		(*pr)("%s: too short mbuf chain\n", __func__);
687 		return m_examine_hex(m, off, modif, pr);
688 	}
689 
690 	if (m_peek_data(m, off, sizeof(ip6), (void *)(&ip6)) < 0) {
691 		(*pr)("%s: cannot read header\n", __func__);
692 		return m_examine_hex(m, off, modif, pr);
693 	}
694 	off += sizeof(ip6);
695 
696 	vfc = ip6.ip6_vfc;
697 	(*pr)("IPv6: Version = %u\n", (vfc & IPV6_VERSION_MASK) >> 4);
698 	flow = ntohl(ip6.ip6_flow);
699 	(*pr)("IPv6: Flow INFO = 0x%07x\n", flow & IPV6_FLOWINFO_MASK);
700 	(*pr)("IPv6: Payload Length = %u\n", ip6.ip6_plen);
701 	nxt = ip6.ip6_nxt;
702 	(*pr)("IPv6: Next Header = %u(%s)\n", nxt, str_ipproto(nxt));
703 	(*pr)("IPv6: Hop Limit = %u\n", ip6.ip6_hlim);
704 	(*pr)("IPv6: Src = %s\n", str_ip6addr(&ip6.ip6_src));
705 	(*pr)("IPv6: Dst = %s\n", str_ip6addr(&ip6.ip6_dst));
706 
707 	/* Strip Hop-by-Hop options */
708 	if (nxt == IPPROTO_HOPOPTS) {
709 		if (m_peek_data(m, off, sizeof(hbh), (void *)(&hbh)) < 0) {
710 			(*pr)("Cannot read option\n");
711 			return m_examine_hex(m, off, modif, pr);
712 		}
713 		hbhlen = (hbh.ip6h_len + 1) << 3;
714 		nxt = hbh.ip6h_nxt;
715 		off += hbhlen;
716 
717 		(*pr)("IPv6: Stripped Hop-by-Hop\n");
718 		(*pr)("IPv6: Next Header = %u(%s)\n", nxt, str_ipproto(nxt));
719 	}
720 
721 	switch (nxt) {
722 	case IPPROTO_IPV6_ICMP:
723 		return m_examine_icmp6(m, off, modif, pr);
724 		break;
725 	case IPPROTO_TCP:
726 		return m_examine_tcp(m, off, modif, pr);
727 		break;
728 	case IPPROTO_UDP:
729 		return m_examine_udp(m, off, modif, pr);
730 		break;
731 	default:
732 		break;
733 	}
734 
735 	return m_examine_hex(m, off, modif, pr);
736 }
737 
738 static void
739 m_examine_icmp6(const struct mbuf *m, int off, const char *modif,
740     void (*pr)(const char *, ...))
741 {
742 	unsigned int pktlen;
743 	struct icmp6_hdr icmp6;
744 
745 	pktlen = m_peek_len(m, modif) - off;
746 	if (pktlen < sizeof(icmp6)) {
747 		(*pr)("%s: too short mbuf chain\n", __func__);
748 		return m_examine_hex(m, off, modif, pr);
749 	}
750 
751 	if (m_peek_data(m, off, sizeof(icmp6), (void *)(&icmp6)) < 0) {
752 		(*pr)("%s: cannot read header\n", __func__);
753 		return m_examine_hex(m, off, modif, pr);
754 	}
755 	off += sizeof(icmp6);
756 
757 	(*pr)("ICMP6: Type = %u(", icmp6.icmp6_type);
758 	switch (icmp6.icmp6_type) {
759 	case ICMP6_DST_UNREACH:
760 		(*pr)("Destination Unreachable)\n");
761 		break;
762 	case ICMP6_PACKET_TOO_BIG:
763 		(*pr)("Packet Too Big)\n");
764 		break;
765 	case ICMP6_TIME_EXCEEDED:
766 		(*pr)("Time Exceeded)\n");
767 		break;
768 	case ICMP6_PARAM_PROB:
769 		(*pr)("Parameter Problem)\n");
770 		break;
771 	case ICMP6_ECHO_REQUEST:
772 		(*pr)("Echo Request)\n");
773 		break;
774 	case ICMP6_ECHO_REPLY:
775 		(*pr)("Echo Reply)\n");
776 		break;
777 
778 	case MLD_LISTENER_QUERY:
779 		(*pr)("MLD Listener Query)\n");
780 		break;
781 	case MLD_LISTENER_REPORT:
782 		(*pr)("MLD Listener Report)\n");
783 		break;
784 	case MLD_LISTENER_DONE:
785 		(*pr)("MLD Listener Done)\n");
786 		break;
787 
788 	case ND_ROUTER_SOLICIT:
789 		(*pr)("Router Solicitation)\n");
790 		break;
791 	case ND_ROUTER_ADVERT:
792 		(*pr)("Router Advertizement)\n");
793 		break;
794 	case ND_NEIGHBOR_SOLICIT:
795 		(*pr)("Neighbor Solicitation)\n");
796 		break;
797 	case ND_NEIGHBOR_ADVERT:
798 		(*pr)("Neighbor Advertizement)\n");
799 		break;
800 	case ND_REDIRECT:
801 		(*pr)("Redirect)\n");
802 		break;
803 
804 	default:
805 		(*pr)("unknown)\n");
806 		break;
807 	}
808 	(*pr)("ICMP6: Code = %u\n", icmp6.icmp6_code);
809 
810 	return m_examine_hex(m, off, modif, pr);
811 }
812 
813 static void
814 m_examine_tcp(const struct mbuf *m, int off, const char *modif,
815     void (*pr)(const char *, ...))
816 {
817 	unsigned int pktlen;
818 	struct tcphdr tcp;
819 
820 	pktlen = m_peek_len(m, modif) - off;
821 	if (pktlen < sizeof(tcp)) {
822 		(*pr)("%s: too short mbuf chain\n", __func__);
823 		return m_examine_hex(m, off, modif, pr);
824 	}
825 
826 	if (m_peek_data(m, off, sizeof(tcp), (void *)(&tcp)) < 0) {
827 		(*pr)("%s: cannot read header\n", __func__);
828 		return m_examine_hex(m, off, modif, pr);
829 	}
830 	off += sizeof(tcp);
831 
832 	(*pr)("TCP: Src = %u\n", ntohs(tcp.th_sport));
833 	(*pr)("TCP: Dst = %u\n", ntohs(tcp.th_dport));
834 	(*pr)("TCP: Seq. = %u\n", ntohl(tcp.th_seq));
835 	(*pr)("TCP: Ack. = %u\n", ntohl(tcp.th_ack));
836 	(*pr)("TCP: Header Length = %u\n", ntohl(tcp.th_off) << 2);
837 	if (tcp.th_flags) {
838 		(*pr)("TCP: Flags 0x%02x : ", tcp.th_flags);
839 		if (tcp.th_flags & TH_FIN)
840 			(*pr)("FIN ");
841 		if (tcp.th_flags & TH_SYN)
842 			(*pr)("SYN ");
843 		if (tcp.th_flags & TH_RST)
844 			(*pr)("RST ");
845 		if (tcp.th_flags & TH_PUSH)
846 			(*pr)("PUSH ");
847 		if (tcp.th_flags & TH_URG)
848 			(*pr)("URG ");
849 		if (tcp.th_flags & TH_ECE)
850 			(*pr)("ECE ");
851 		if (tcp.th_flags & TH_CWR)
852 			(*pr)("CWR ");
853 		(*pr)("\n");
854 	}
855 	(*pr)("TCP: Windows Size = %u\n", ntohs(tcp.th_win));
856 	(*pr)("TCP: Urgent Pointer = %u\n", ntohs(tcp.th_urp));
857 
858 	return m_examine_hex(m, off, modif, pr);
859 }
860 
861 static void
862 m_examine_udp(const struct mbuf *m, int off, const char *modif,
863     void (*pr)(const char *, ...))
864 {
865 	unsigned int pktlen;
866 	struct udphdr udp;
867 
868 	pktlen = m_peek_len(m, modif) - off;
869 	if (pktlen < sizeof(udp)) {
870 		(*pr)("%s: too short mbuf chain\n", __func__);
871 		return m_examine_hex(m, off, modif, pr);
872 	}
873 
874 	if (m_peek_data(m, off, sizeof(udp), (void *)(&udp)) < 0) {
875 		(*pr)("%s: cannot read header\n", __func__);
876 		return m_examine_hex(m, off, modif, pr);
877 	}
878 	off += sizeof(udp);
879 
880 	(*pr)("UDP: Src = %u\n", ntohs(udp.uh_sport));
881 	(*pr)("UDP: Dst = %u\n", ntohs(udp.uh_dport));
882 	(*pr)("UDP: Length = %u\n", ntohs(udp.uh_ulen));
883 
884 	return m_examine_hex(m, off, modif, pr);
885 }
886 
887 static void
888 m_examine_hex(const struct mbuf *m, int off, const char *modif,
889     void (*pr)(const char *, ...))
890 {
891 	unsigned int pktlen;
892 	int newline = 0;
893 	uint8_t v;
894 
895 	pktlen = m_peek_len(m, modif) - off;
896 	if (pktlen > EXAMINE_HEX_LIMIT)
897 		pktlen = EXAMINE_HEX_LIMIT;
898 
899 	if (pktlen == 0)
900 		return;
901 
902 	(*pr)("offset %04d: ", off);
903 	while (pktlen > 0) {
904 		if (m_peek_data(m, off, sizeof(v), (void *)(&v)) < 0)
905 			break;
906 		pktlen --;
907 		off++;
908 		newline++;
909 
910 		(*pr)("%02x", v);
911 		if (pktlen == 0)
912 			break;
913 
914 		if ((newline % EXAMINE_HEX_COL) == 0) {
915 			(*pr)("\n");
916 			(*pr)("offset %04d: ", off);
917 		}
918 		else {
919 			(*pr)(" ");
920 		}
921 	}
922 	(*pr)("\n");
923 }
924 
925 void
926 m_examine(const struct mbuf *m, int af, const char *modif,
927     void (*pr)(const char *, ...))
928 {
929 	if (m == NULL)
930 		return;
931 
932 	if (pr == NULL)
933 		return;
934 
935 	switch (af) {
936 	case AF_UNSPEC:
937 		return m_examine_hex(m, 0, modif, pr);
938 		break;
939 	case AF_ETHER:
940 		return m_examine_ether(m, 0, modif, pr);
941 		break;
942 	case AF_ARP:
943 		return m_examine_arp(m, 0, modif, pr);
944 		break;
945 	case AF_INET:
946 		return m_examine_ip(m, 0, modif, pr);
947 		break;
948 	case AF_INET6:
949 		return m_examine_ip6(m, 0, modif, pr);
950 		break;
951 	default:
952 		(*pr)("No parser for AF %d\n", af);
953 		return m_examine_hex(m, 0, modif, pr);
954 		break;
955 	}
956 
957 	/* not reached */
958 	return;
959 }
960