print-ospf6.c revision 75115 
1/*
2 * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * OSPF support contributed by Jeffrey Honig (jch@mitchell.cit.cornell.edu)
22 */
23
24#ifndef lint
25static const char rcsid[] =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-ospf6.c,v 1.6 2000/09/29 04:58:45 guy Exp $ (LBL)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <sys/param.h>
34#include <sys/time.h>
35#include <sys/socket.h>
36
37#include <netinet/in.h>
38
39#include <ctype.h>
40#include <stdio.h>
41#include <string.h>
42
43#include "interface.h"
44#include "addrtoname.h"
45
46#include "ospf6.h"
47
48struct bits {
49	u_int32_t bit;
50	const char *str;
51};
52
53static const struct bits ospf6_option_bits[] = {
54	{ OSPF6_OPTION_V6,	"V6" },
55	{ OSPF6_OPTION_E,	"E" },
56	{ OSPF6_OPTION_MC,	"MC" },
57	{ OSPF6_OPTION_N,	"N" },
58	{ OSPF6_OPTION_R,	"R" },
59	{ OSPF6_OPTION_DC,	"DC" },
60	{ 0,			NULL }
61};
62
63static const struct bits ospf6_rla_flag_bits[] = {
64	{ RLA_FLAG_B,		"B" },
65	{ RLA_FLAG_E,		"E" },
66	{ RLA_FLAG_V,		"V" },
67	{ RLA_FLAG_W,		"W" },
68	{ 0,			NULL }
69};
70
71static const struct bits ospf6_asla_flag_bits[] = {
72	{ ASLA_FLAG_EXTERNAL,	"E" },
73	{ ASLA_FLAG_FWDADDR,	"F" },
74	{ ASLA_FLAG_ROUTETAG,	"T" },
75	{ 0,			NULL }
76};
77
78static struct tok type2str[] = {
79	{ OSPF_TYPE_UMD,	"umd" },
80	{ OSPF_TYPE_HELLO,	"hello" },
81	{ OSPF_TYPE_DB,		"dd" },
82	{ OSPF_TYPE_LSR,	"ls_req" },
83	{ OSPF_TYPE_LSU,	"ls_upd" },
84	{ OSPF_TYPE_LSA,	"ls_ack" },
85	{ 0,			NULL }
86};
87
88static char tstr[] = " [|ospf]";
89
90/* Forwards */
91static inline void ospf6_print_seqage(u_int32_t, time_t);
92static inline void ospf6_print_bits(const struct bits *, u_char);
93static void ospf6_print_ls_type(u_int, const rtrid_t *,
94    const rtrid_t *, const char *);
95static int ospf6_print_lshdr(const struct lsa_hdr *);
96static int ospf6_print_lsa(const struct lsa *);
97static int ospf6_decode_v3(const struct ospf6hdr *, const u_char *);
98
99static inline void
100ospf6_print_seqage(register u_int32_t seq, register time_t us)
101{
102	register time_t sec = us % 60;
103	register time_t mins = (us / 60) % 60;
104	register time_t hour = us / 3600;
105
106	printf(" S %X age ", seq);
107	if (hour)
108		printf("%u:%02u:%02u",
109		    (u_int32_t) hour, (u_int32_t) mins, (u_int32_t) sec);
110	else if (mins)
111		printf("%u:%02u", (u_int32_t) mins, (u_int32_t) sec);
112	else
113		printf("%u", (u_int32_t) sec);
114}
115
116
117static inline void
118ospf6_print_bits(register const struct bits *bp, register u_char options)
119{
120	register char sep = ' ';
121
122	do {
123		if (options & bp->bit) {
124			printf("%c%s", sep, bp->str);
125			sep = '/';
126		}
127	} while ((++bp)->bit);
128}
129
130static void
131ospf6_print_ls_type(register u_int ls_type,
132    register const rtrid_t *ls_stateid,
133    register const rtrid_t *ls_router, register const char *fmt)
134{
135	char *scope;
136
137	switch (ls_type & LS_SCOPE_MASK) {
138	case LS_SCOPE_LINKLOCAL:
139		scope = "linklocal-";
140		break;
141	case LS_SCOPE_AREA:
142		scope = "area-";
143		break;
144	case LS_SCOPE_AS:
145		scope = "AS-";
146		break;
147	default:
148		scope = "";
149		break;
150	}
151
152	switch (ls_type & LS_TYPE_MASK) {
153	case LS_TYPE_ROUTER:
154		printf(" %srtr %s", scope, ipaddr_string(ls_router));
155		break;
156
157	case LS_TYPE_NETWORK:
158		printf(" %snet dr %s if %s", scope,
159		    ipaddr_string(ls_router),
160		    ipaddr_string(ls_stateid));
161		break;
162
163	case LS_TYPE_INTER_AP:
164		printf(" %sinter-area-prefix %s abr %s", scope,
165		    ipaddr_string(ls_stateid),
166		    ipaddr_string(ls_router));
167		break;
168
169	case LS_TYPE_INTER_AR:
170		printf(" %sinter-area-router %s rtr %s", scope,
171		    ipaddr_string(ls_router),
172		    ipaddr_string(ls_stateid));
173		break;
174
175	case LS_TYPE_ASE:
176		printf(" %sase %s asbr %s", scope,
177		    ipaddr_string(ls_stateid),
178		    ipaddr_string(ls_router));
179		break;
180
181	case LS_TYPE_GROUP:
182		printf(" %sgroup %s rtr %s", scope,
183		    ipaddr_string(ls_stateid),
184		    ipaddr_string(ls_router));
185		break;
186
187	case LS_TYPE_TYPE7:
188		printf(" %stype7 %s rtr %s", scope,
189		    ipaddr_string(ls_stateid),
190		    ipaddr_string(ls_router));
191		break;
192
193	case LS_TYPE_LINK:
194		printf(" %slink %s rtr %s", scope,
195		    ipaddr_string(ls_stateid),
196		    ipaddr_string(ls_router));
197		break;
198
199	case LS_TYPE_INTRA_AP:
200		printf(" %sintra-area-prefix %s rtr %s", scope,
201		    ipaddr_string(ls_stateid),
202		    ipaddr_string(ls_router));
203		break;
204
205	default:
206		printf(" %s", scope);
207		printf(fmt, ls_type);
208		break;
209	}
210
211}
212
213static int
214ospf6_print_lshdr(register const struct lsa_hdr *lshp)
215{
216
217	TCHECK(lshp->ls_type);
218	printf(" {");						/* } (ctags) */
219
220	TCHECK(lshp->ls_seq);
221	ospf6_print_seqage(ntohl(lshp->ls_seq), ntohs(lshp->ls_age));
222	ospf6_print_ls_type(ntohs(lshp->ls_type), &lshp->ls_stateid,
223		&lshp->ls_router, "ls_type %d");
224
225	return (0);
226trunc:
227	return (1);
228}
229
230static int
231ospf6_print_lsaprefix(register const struct lsa_prefix *lsapp)
232{
233	int k;
234	struct in6_addr prefix;
235
236	TCHECK(*lsapp);
237	k = (lsapp->lsa_p_len + 31) / 32;
238	if (k * 4 > sizeof(struct in6_addr)) {
239		printf("??prefixlen %d??", lsapp->lsa_p_len);
240		goto trunc;
241	}
242	memset(&prefix, 0, sizeof(prefix));
243	memcpy(&prefix, lsapp->lsa_p_prefix, k * 4);
244	printf(" %s/%d", ip6addr_string(&prefix),
245		lsapp->lsa_p_len);
246	if (lsapp->lsa_p_opt)
247		printf("(opt=%x)", lsapp->lsa_p_opt);
248	if (lsapp->lsa_p_mbz)
249		printf("(mbz=%x)", ntohs(lsapp->lsa_p_mbz)); /* XXX */
250	return sizeof(*lsapp) - 4 + k * 4;
251
252trunc:
253	return -1;
254}
255
256
257/*
258 * Print a single link state advertisement.  If truncated return 1, else 0.
259 */
260static int
261ospf6_print_lsa(register const struct lsa *lsap)
262{
263	register const u_char *ls_end, *ls_opt;
264	register const struct rlalink *rlp;
265#if 0
266	register const struct tos_metric *tosp;
267#endif
268	register const rtrid_t *ap;
269#if 0
270	register const struct aslametric *almp;
271	register const struct mcla *mcp;
272#endif
273	register const struct llsa *llsap;
274	register const struct lsa_prefix *lsapp;
275#if 0
276	register const u_int32_t *lp;
277#endif
278	register int j, k;
279	u_int32_t flags32;
280
281	if (ospf6_print_lshdr(&lsap->ls_hdr))
282		return (1);
283	TCHECK(lsap->ls_hdr.ls_length);
284	ls_end = (u_char *)lsap + ntohs(lsap->ls_hdr.ls_length);
285	switch (ntohs(lsap->ls_hdr.ls_type)) {
286	case LS_TYPE_ROUTER | LS_SCOPE_AREA:
287		TCHECK(lsap->lsa_un.un_rla.rla_flags);
288		ospf6_print_bits(ospf6_rla_flag_bits,
289			lsap->lsa_un.un_rla.rla_flags);
290		TCHECK(lsap->lsa_un.un_rla.rla_options);
291		ospf6_print_bits(ospf6_option_bits,
292			ntohl(lsap->lsa_un.un_rla.rla_options));
293
294		TCHECK(lsap->lsa_un.un_rla.rla_link);
295		rlp = lsap->lsa_un.un_rla.rla_link;
296		while (rlp + sizeof(*rlp) <= (struct rlalink *)ls_end) {
297			TCHECK(*rlp);
298			printf(" {");				/* } (ctags) */
299			switch (rlp->link_type) {
300
301			case RLA_TYPE_VIRTUAL:
302				printf(" virt");
303				/* Fall through */
304
305			case RLA_TYPE_ROUTER:
306				printf(" nbrid %s nbrif %s if %s",
307				    ipaddr_string(&rlp->link_nrtid),
308				    ipaddr_string(&rlp->link_nifid),
309				    ipaddr_string(&rlp->link_ifid));
310				break;
311
312			case RLA_TYPE_TRANSIT:
313				printf(" dr %s drif %s if %s",
314				    ipaddr_string(&rlp->link_nrtid),
315				    ipaddr_string(&rlp->link_nifid),
316				    ipaddr_string(&rlp->link_ifid));
317				break;
318
319			default:
320								/* { (ctags) */
321				printf(" ??RouterLinksType 0x%02x?? }",
322				    rlp->link_type);
323				return (0);
324			}
325			printf(" metric %d", ntohs(rlp->link_metric));
326								/* { (ctags) */
327			printf(" }");
328			rlp++;
329		}
330		break;
331
332	case LS_TYPE_NETWORK | LS_SCOPE_AREA:
333		TCHECK(lsap->lsa_un.un_nla.nla_options);
334		ospf6_print_bits(ospf6_option_bits,
335			ntohl(lsap->lsa_un.un_nla.nla_options));
336		printf(" rtrs");
337		ap = lsap->lsa_un.un_nla.nla_router;
338		while ((u_char *)ap < ls_end) {
339			TCHECK(*ap);
340			printf(" %s", ipaddr_string(ap));
341			++ap;
342		}
343		break;
344
345	case LS_TYPE_INTER_AP | LS_SCOPE_AREA:
346		TCHECK(lsap->lsa_un.un_inter_ap.inter_ap_metric);
347		printf(" metric %u",
348			(u_int32_t)ntohl(lsap->lsa_un.un_inter_ap.inter_ap_metric) & SLA_MASK_METRIC);
349		lsapp = lsap->lsa_un.un_inter_ap.inter_ap_prefix;
350		while (lsapp + sizeof(lsapp) <= (struct lsa_prefix *)ls_end) {
351			k = ospf6_print_lsaprefix(lsapp);
352			if (k)
353				goto trunc;
354			lsapp = (struct lsa_prefix *)(((u_char *)lsapp) + k);
355		}
356		break;
357	case LS_SCOPE_AS | LS_TYPE_ASE:
358		TCHECK(lsap->lsa_un.un_asla.asla_metric);
359		flags32 = ntohl(lsap->lsa_un.un_asla.asla_metric);
360		ospf6_print_bits(ospf6_asla_flag_bits, flags32);
361		printf(" metric %u",
362		       ntohl(lsap->lsa_un.un_asla.asla_metric) &
363		       ASLA_MASK_METRIC);
364		lsapp = lsap->lsa_un.un_asla.asla_prefix;
365		k = ospf6_print_lsaprefix(lsapp);
366		if (k < 0)
367			goto trunc;
368		if ((ls_opt = (u_char *)(((u_char *)lsapp) + k)) < ls_end) {
369			struct in6_addr *fwdaddr6;
370
371			if ((flags32 & ASLA_FLAG_FWDADDR) != 0) {
372				fwdaddr6 = (struct in6_addr *)ls_opt;
373				TCHECK(*fwdaddr6);
374				printf(" forward %s",
375				       ip6addr_string(fwdaddr6));
376
377				ls_opt += sizeof(struct in6_addr);
378			}
379
380			if ((flags32 & ASLA_FLAG_ROUTETAG) != 0) {
381				TCHECK(*(u_int32_t *)ls_opt);
382				printf(" tag %s",
383				       ipaddr_string((u_int32_t *)ls_opt));
384
385				ls_opt += sizeof(u_int32_t);
386			}
387
388			if (lsapp->lsa_p_mbz) {
389				TCHECK(*(u_int32_t *)ls_opt);
390				printf(" RefLSID: %s",
391				       ipaddr_string((u_int32_t *)ls_opt));
392
393				ls_opt += sizeof(u_int32_t);
394			}
395		}
396		break;
397#if 0
398	case LS_TYPE_SUM_ABR:
399		TCHECK(lsap->lsa_un.un_sla.sla_tosmetric);
400		lp = lsap->lsa_un.un_sla.sla_tosmetric;
401		while ((u_char *)lp < ls_end) {
402			register u_int32_t ul;
403
404			TCHECK(*lp);
405			ul = ntohl(*lp);
406			printf(" tos %d metric %d",
407			    (ul & SLA_MASK_TOS) >> SLA_SHIFT_TOS,
408			    ul & SLA_MASK_METRIC);
409			++lp;
410		}
411		break;
412
413	case LS_TYPE_GROUP:
414		/* Multicast extensions as of 23 July 1991 */
415		mcp = lsap->lsa_un.un_mcla;
416		while ((u_char *)mcp < ls_end) {
417			TCHECK(mcp->mcla_vid);
418			switch (ntohl(mcp->mcla_vtype)) {
419
420			case MCLA_VERTEX_ROUTER:
421				printf(" rtr rtrid %s",
422				    ipaddr_string(&mcp->mcla_vid));
423				break;
424
425			case MCLA_VERTEX_NETWORK:
426				printf(" net dr %s",
427				    ipaddr_string(&mcp->mcla_vid));
428				break;
429
430			default:
431				printf(" ??VertexType %u??",
432				    (u_int32_t)ntohl(mcp->mcla_vtype));
433				break;
434			}
435		++mcp;
436		}
437#endif
438
439	case LS_TYPE_LINK:
440		/* Link LSA */
441		llsap = &lsap->lsa_un.un_llsa;
442		TCHECK(llsap->llsa_options);
443		ospf6_print_bits(ospf6_option_bits, ntohl(llsap->llsa_options));
444		TCHECK(llsap->llsa_nprefix);
445		printf(" pri %d lladdr %s npref %d", llsap->llsa_priority,
446			ip6addr_string(&llsap->llsa_lladdr),
447			(u_int32_t)ntohl(llsap->llsa_nprefix));
448		lsapp = llsap->llsa_prefix;
449		for (j = 0; j < ntohl(llsap->llsa_nprefix); j++) {
450			k = ospf6_print_lsaprefix(lsapp);
451			if (k)
452				goto trunc;
453			lsapp = (struct lsa_prefix *)(((u_char *)lsapp) + k);
454		}
455		break;
456
457	case LS_TYPE_INTRA_AP | LS_SCOPE_AREA:
458		/* Intra-Area-Prefix LSA */
459		TCHECK(lsap->lsa_un.un_intra_ap.intra_ap_rtid);
460		ospf6_print_ls_type(
461			ntohs(lsap->lsa_un.un_intra_ap.intra_ap_lstype),
462			&lsap->lsa_un.un_intra_ap.intra_ap_lsid,
463			&lsap->lsa_un.un_intra_ap.intra_ap_rtid,
464			"LinkStateType %d");
465		TCHECK(lsap->lsa_un.un_intra_ap.intra_ap_nprefix);
466		printf(" npref %d",
467			ntohs(lsap->lsa_un.un_intra_ap.intra_ap_nprefix));
468
469		lsapp = lsap->lsa_un.un_intra_ap.intra_ap_prefix;
470		for (j = 0;
471		     j < ntohs(lsap->lsa_un.un_intra_ap.intra_ap_nprefix);
472		     j++) {
473			k = ospf6_print_lsaprefix(lsapp);
474			if (k)
475				goto trunc;
476			lsapp = (struct lsa_prefix *)(((u_char *)lsapp) + k);
477		}
478		break;
479
480	default:
481		printf(" ??LinkStateType 0x%04x??",
482			ntohs(lsap->ls_hdr.ls_type));
483	}
484
485								/* { (ctags) */
486	fputs(" }", stdout);
487	return (0);
488trunc:
489	fputs(" }", stdout);
490	return (1);
491}
492
493static int
494ospf6_decode_v3(register const struct ospf6hdr *op,
495    register const u_char *dataend)
496{
497	register const rtrid_t *ap;
498	register const struct lsr *lsrp;
499	register const struct lsa_hdr *lshp;
500	register const struct lsa *lsap;
501	register char sep;
502	register int i;
503
504	switch (op->ospf6_type) {
505
506	case OSPF_TYPE_UMD:
507		/*
508		 * Rob Coltun's special monitoring packets;
509		 * do nothing
510		 */
511		break;
512
513	case OSPF_TYPE_HELLO:
514		if (vflag) {
515			TCHECK(op->ospf6_hello.hello_deadint);
516			ospf6_print_bits(ospf6_option_bits,
517			    ntohl(op->ospf6_hello.hello_options));
518			printf(" ifid %s pri %d int %d dead %u",
519			    ipaddr_string(&op->ospf6_hello.hello_ifid),
520			    op->ospf6_hello.hello_priority,
521			    ntohs(op->ospf6_hello.hello_helloint),
522			    ntohs(op->ospf6_hello.hello_deadint));
523		}
524		TCHECK(op->ospf6_hello.hello_dr);
525		if (op->ospf6_hello.hello_dr != 0)
526			printf(" dr %s",
527			    ipaddr_string(&op->ospf6_hello.hello_dr));
528		TCHECK(op->ospf6_hello.hello_bdr);
529		if (op->ospf6_hello.hello_bdr != 0)
530			printf(" bdr %s",
531			    ipaddr_string(&op->ospf6_hello.hello_bdr));
532		if (vflag) {
533			printf(" nbrs");
534			ap = op->ospf6_hello.hello_neighbor;
535			while ((u_char *)ap < dataend) {
536				TCHECK(*ap);
537				printf(" %s", ipaddr_string(ap));
538				++ap;
539			}
540		}
541		break;	/* HELLO */
542
543	case OSPF_TYPE_DB:
544		TCHECK(op->ospf6_db.db_options);
545		ospf6_print_bits(ospf6_option_bits,
546			ntohl(op->ospf6_db.db_options));
547		sep = ' ';
548		TCHECK(op->ospf6_db.db_flags);
549		if (op->ospf6_db.db_flags & OSPF6_DB_INIT) {
550			printf("%cI", sep);
551			sep = '/';
552		}
553		if (op->ospf6_db.db_flags & OSPF6_DB_MORE) {
554			printf("%cM", sep);
555			sep = '/';
556		}
557		if (op->ospf6_db.db_flags & OSPF6_DB_MASTER) {
558			printf("%cMS", sep);
559			sep = '/';
560		}
561		TCHECK(op->ospf6_db.db_seq);
562		printf(" mtu %u S %X", ntohs(op->ospf6_db.db_mtu),
563			(u_int32_t)ntohl(op->ospf6_db.db_seq));
564
565		if (vflag) {
566			/* Print all the LS adv's */
567			lshp = op->ospf6_db.db_lshdr;
568
569			while (!ospf6_print_lshdr(lshp)) {
570							/* { (ctags) */
571				printf(" }");
572				++lshp;
573			}
574		}
575		break;
576
577	case OSPF_TYPE_LSR:
578		if (vflag) {
579			lsrp = op->ospf6_lsr;
580			while ((u_char *)lsrp < dataend) {
581				TCHECK(*lsrp);
582				printf(" {");		/* } (ctags) */
583				ospf6_print_ls_type(ntohs(lsrp->ls_type),
584				    &lsrp->ls_stateid,
585				    &lsrp->ls_router,
586				    "LinkStateType %d");
587							/* { (ctags) */
588				printf(" }");
589				++lsrp;
590			}
591		}
592		break;
593
594	case OSPF_TYPE_LSU:
595		if (vflag) {
596			lsap = op->ospf6_lsu.lsu_lsa;
597			TCHECK(op->ospf6_lsu.lsu_count);
598			i = ntohl(op->ospf6_lsu.lsu_count);
599			while (i--) {
600				if (ospf6_print_lsa(lsap))
601					goto trunc;
602				lsap = (struct lsa *)((u_char *)lsap +
603				    ntohs(lsap->ls_hdr.ls_length));
604			}
605		}
606		break;
607
608
609	case OSPF_TYPE_LSA:
610		if (vflag) {
611			lshp = op->ospf6_lsa.lsa_lshdr;
612
613			while (!ospf6_print_lshdr(lshp)) {
614							/* { (ctags) */
615				printf(" }");
616				++lshp;
617			}
618		}
619		break;
620
621	default:
622		printf("v3 type %d", op->ospf6_type);
623		break;
624	}
625	return (0);
626trunc:
627	return (1);
628}
629
630void
631ospf6_print(register const u_char *bp, register u_int length)
632{
633	register const struct ospf6hdr *op;
634	register const u_char *dataend;
635	register const char *cp;
636
637	op = (struct ospf6hdr *)bp;
638
639	/* If the type is valid translate it, or just print the type */
640	/* value.  If it's not valid, say so and return */
641	TCHECK(op->ospf6_type);
642	cp = tok2str(type2str, "type%d", op->ospf6_type);
643	printf("OSPFv%d-%s %d:", op->ospf6_version, cp, length);
644	if (*cp == 't')
645		return;
646
647	TCHECK(op->ospf6_len);
648	if (length != ntohs(op->ospf6_len)) {
649		printf(" [len %d]", ntohs(op->ospf6_len));
650		return;
651	}
652	dataend = bp + length;
653
654	/* Print the routerid if it is not the same as the source */
655	TCHECK(op->ospf6_routerid);
656	printf(" rtrid %s", ipaddr_string(&op->ospf6_routerid));
657
658	TCHECK(op->ospf6_areaid);
659	if (op->ospf6_areaid != 0)
660		printf(" area %s", ipaddr_string(&op->ospf6_areaid));
661	else
662		printf(" backbone");
663	TCHECK(op->ospf6_instanceid);
664	if (op->ospf6_instanceid)
665		printf(" instance %u", op->ospf6_instanceid);
666
667	/* Do rest according to version.	 */
668	switch (op->ospf6_version) {
669
670	case 3:
671		/* ospf version 3 */
672		if (ospf6_decode_v3(op, dataend))
673			goto trunc;
674		break;
675
676	default:
677		printf(" ospf [version %d]", op->ospf6_version);
678		break;
679	}			/* end switch on version */
680
681	return;
682trunc:
683	fputs(tstr, stdout);
684}
685