xref: /freebsd/usr.bin/netstat/main.c (revision 5129159789cc9d7bc514e4546b88e3427695002d)
1 /*
2  * Copyright (c) 1983, 1988, 1993
3  *	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 the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 char const copyright[] =
36 "@(#) Copyright (c) 1983, 1988, 1993\n\
37 	Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)main.c	8.4 (Berkeley) 3/1/94";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif /* not lint */
47 
48 #include <sys/param.h>
49 #include <sys/file.h>
50 #include <sys/protosw.h>
51 #include <sys/socket.h>
52 
53 #include <netinet/in.h>
54 
55 #include <netgraph/ng_socket.h>
56 
57 #include <ctype.h>
58 #include <err.h>
59 #include <errno.h>
60 #include <kvm.h>
61 #include <limits.h>
62 #include <netdb.h>
63 #include <nlist.h>
64 #include <paths.h>
65 #include <stdio.h>
66 #include <stdlib.h>
67 #include <string.h>
68 #include <unistd.h>
69 #include "netstat.h"
70 
71 static struct nlist nl[] = {
72 #define	N_IFNET		0
73 	{ "_ifnet" },
74 #define	N_IMP		1
75 	{ "_imp_softc" },
76 #define	N_RTSTAT	2
77 	{ "_rtstat" },
78 #define	N_UNIXSW	3
79 	{ "_localsw" },
80 #define N_IDP		4
81 	{ "_nspcb"},
82 #define N_IDPSTAT	5
83 	{ "_idpstat"},
84 #define N_SPPSTAT	6
85 	{ "_spp_istat"},
86 #define N_NSERR		7
87 	{ "_ns_errstat"},
88 #define	N_CLNPSTAT	8
89 	{ "_clnp_stat"},
90 #define	IN_NOTUSED	9
91 	{ "_tp_inpcb" },
92 #define	ISO_TP		10
93 	{ "_tp_refinfo" },
94 #define	N_TPSTAT	11
95 	{ "_tp_stat" },
96 #define	N_ESISSTAT	12
97 	{ "_esis_stat"},
98 #define N_NIMP		13
99 	{ "_nimp"},
100 #define N_RTREE		14
101 	{ "_rt_tables"},
102 #define N_CLTP		15
103 	{ "_cltb"},
104 #define N_CLTPSTAT	16
105 	{ "_cltpstat"},
106 #define	N_NFILE		17
107 	{ "_nfile" },
108 #define	N_FILE		18
109 	{ "_file" },
110 #define N_MRTSTAT	19
111 	{ "_mrtstat" },
112 #define N_MFCTABLE	20
113 	{ "_mfctable" },
114 #define N_VIFTABLE	21
115 	{ "_viftable" },
116 #define N_IPX		22
117 	{ "_ipxpcb"},
118 #define N_IPXSTAT	23
119 	{ "_ipxstat"},
120 #define N_SPXSTAT	24
121 	{ "_spx_istat"},
122 #define N_DDPSTAT	25
123 	{ "_ddpstat"},
124 #define N_DDPCB		26
125 	{ "_ddpcb"},
126 #define N_NGSOCKS	27
127 	{ "_ngsocklist"},
128 #define N_IP6STAT	28
129 	{ "_ip6stat" },
130 #define N_ICMP6STAT	29
131 	{ "_icmp6stat" },
132 #ifdef notyet
133 #define N_IPSECSTAT	30
134 	{ "_ipsecstat" },
135 #define N_IPSEC6STAT	31
136 	{ "_ipsec6stat" },
137 #define N_PIM6STAT	32
138 	{ "_pim6stat" },
139 #define N_MRT6PROTO	33
140 	{ "_ip6_mrtproto" },
141 #define N_MRT6STAT	34
142 	{ "_mrt6stat" },
143 #define N_MF6CTABLE	35
144 	{ "_mf6ctable" },
145 #define N_MIF6TABLE	36
146 	{ "_mif6table" },
147 #endif
148 	{ "" },
149 };
150 
151 struct protox {
152 	u_char	pr_index;		/* index into nlist of cb head */
153 	u_char	pr_sindex;		/* index into nlist of stat block */
154 	u_char	pr_wanted;		/* 1 if wanted, 0 otherwise */
155 	void	(*pr_cblocks)();	/* control blocks printing routine */
156 	void	(*pr_stats)();		/* statistics printing routine */
157 	void	(*pr_istats)();		/* per/if statistics printing routine */
158 	char	*pr_name;		/* well-known name */
159 	int	pr_usesysctl;		/* true if we use sysctl, not kvm */
160 } protox[] = {
161 	{ -1,		-1,		1,	protopr,
162 	  tcp_stats,	NULL,		"tcp",	IPPROTO_TCP },
163 	{ -1,		-1,		1,	protopr,
164 	  udp_stats,	NULL,		"udp",	IPPROTO_UDP },
165 	{ -1,		-1,		1,	protopr,
166 	  NULL,		NULL,		"divert",IPPROTO_DIVERT },
167 	{ -1,		-1,		1,	protopr,
168 	  ip_stats,	NULL,		"ip",	IPPROTO_RAW },
169 	{ -1,		-1,		1,	protopr,
170 	  icmp_stats,	NULL,		"icmp",	IPPROTO_ICMP },
171 	{ -1,		-1,		1,	protopr,
172 	  igmp_stats,	NULL,		"igmp",	IPPROTO_IGMP },
173 #ifdef IPSEC
174 	{ -1,		N_IPSECSTAT,	1,	0,
175 	  ipsec_stats,	NULL,		"ipsec",	0},
176 #endif
177 	{ -1,		-1,		1,	protopr,
178 	  bdg_stats,	NULL,		"bdg",	1 /* bridging... */ },
179 	{ -1,		-1,		0,	0,
180 	  0,		NULL,		0 }
181 };
182 
183 #ifdef INET6
184 struct protox ip6protox[] = {
185 	{ -1,		-1,		1,	protopr,
186 	  tcp_stats,	NULL,		"tcp",	IPPROTO_TCP },
187 	{ -1,		-1,		1,	protopr,
188 	  udp_stats,	NULL,		"udp",	IPPROTO_UDP },
189 	{ -1,		N_IP6STAT,	1,	0,
190 	  ip6_stats,	ip6_ifstats,	"ip6",	0 },
191 	{ -1,		N_ICMP6STAT,	1,	0,
192 	  icmp6_stats,	icmp6_ifstats,	"icmp6",0 },
193 #ifdef IPSEC
194 	{ -1,		N_IPSEC6STAT,	1,	0,
195 	  ipsec_stats,	NULL,		"ipsec6",0 },
196 #endif
197 #ifdef notyet
198 	{ -1,		N_PIM6STAT,	1,	0,
199 	  pim6_stats,	NULL,		"pim6",	0 },
200 #endif
201 	{ -1,		-1,		1,	protopr,
202 	  bdg_stats,	NULL,		"bdg",	1 /* bridging... */ },
203 	{ -1,		-1,		0,	0,
204 	  0,		NULL,		0,	0 }
205 };
206 #endif /*INET6*/
207 
208 struct protox atalkprotox[] = {
209 	{ N_DDPCB,	N_DDPSTAT,	1,	atalkprotopr,
210 	  ddp_stats,	NULL,		"ddp" },
211 	{ -1,		-1,		0,	0,
212 	  0,		NULL,		0 }
213 };
214 
215 struct protox netgraphprotox[] = {
216 	{ N_NGSOCKS,	-1,		1,	netgraphprotopr,
217 	  NULL,		NULL,		"ctrl" },
218 	{ N_NGSOCKS,	-1,		1,	netgraphprotopr,
219 	  NULL,		NULL,		"data" },
220 	{ -1,		NULL,		0,	0,
221 	  0,		NULL,		0 }
222 };
223 
224 struct protox ipxprotox[] = {
225 	{ N_IPX,	N_IPXSTAT,	1,	ipxprotopr,
226 	  ipx_stats,	NULL,		"ipx",	0 },
227 	{ N_IPX,	N_SPXSTAT,	1,	ipxprotopr,
228 	  spx_stats,	NULL,		"spx",	0 },
229 	{ -1,		-1,		0,	0,
230 	  0,		NULL,		0,	0 }
231 };
232 
233 #ifdef NS
234 struct protox nsprotox[] = {
235 	{ N_IDP,	N_IDPSTAT,	1,	nsprotopr,
236 	  idp_stats,	NULL,		"idp" },
237 	{ N_IDP,	N_SPPSTAT,	1,	nsprotopr,
238 	  spp_stats,	NULL,		"spp" },
239 	{ -1,		N_NSERR,	1,	0,
240 	  nserr_stats,	NULL,		"ns_err" },
241 	{ -1,		-1,		0,	0,
242 	  0,		NULL,		0 }
243 };
244 #endif
245 
246 #ifdef ISO
247 struct protox isoprotox[] = {
248 	{ ISO_TP,	N_TPSTAT,	1,	iso_protopr,
249 	  tp_stats,	NULL,		"tp" },
250 	{ N_CLTP,	N_CLTPSTAT,	1,	iso_protopr,
251 	  cltp_stats,	NULL,		"cltp" },
252 	{ -1,		N_CLNPSTAT,	1,	 0,
253 	  clnp_stats,	NULL,		"clnp"},
254 	{ -1,		N_ESISSTAT,	1,	 0,
255 	  esis_stats,	NULL,		"esis"},
256 	{ -1,		-1,		0,	0,
257 	  0,		NULL,		0 }
258 };
259 #endif
260 
261 struct protox *protoprotox[] = {
262 					 protox,
263 #ifdef INET6
264 					 ip6protox,
265 #endif
266 					 ipxprotox, atalkprotox,
267 #ifdef NS
268 					 nsprotox,
269 #endif
270 #ifdef ISO
271 					 isoprotox,
272 #endif
273 					 NULL };
274 
275 static void printproto __P((struct protox *, char *));
276 static void usage __P((void));
277 static struct protox *name2protox __P((char *));
278 static struct protox *knownname __P((char *));
279 
280 static kvm_t *kvmd;
281 char *nlistf = NULL, *memf = NULL;
282 
283 int
284 main(argc, argv)
285 	int argc;
286 	char *argv[];
287 {
288 	register struct protox *tp = NULL;  /* for printing cblocks & stats */
289 	int ch;
290 
291 	af = AF_UNSPEC;
292 
293 	while ((ch = getopt(argc, argv, "Aabdf:ghI:lLiM:mN:np:rstuw:")) != -1)
294 		switch(ch) {
295 		case 'A':
296 			Aflag = 1;
297 			break;
298 		case 'a':
299 			aflag = 1;
300 			break;
301 		case 'b':
302 			bflag = 1;
303 			break;
304 		case 'd':
305 			dflag = 1;
306 			break;
307 		case 'f':
308 #ifdef NS
309 			if (strcmp(optarg, "ns") == 0)
310 				af = AF_NS;
311 			else
312 #endif
313 			if (strcmp(optarg, "ipx") == 0)
314 				af = AF_IPX;
315 			else if (strcmp(optarg, "inet") == 0)
316 				af = AF_INET;
317 #ifdef INET6
318 			else if (strcmp(optarg, "inet6") == 0)
319 				af = AF_INET6;
320 #endif /*INET6*/
321 			else if (strcmp(optarg, "unix") == 0)
322 				af = AF_UNIX;
323 			else if (strcmp(optarg, "atalk") == 0)
324 				af = AF_APPLETALK;
325 			else if (strcmp(optarg, "ng") == 0
326 			    || strcmp(optarg, "netgraph") == 0)
327 				af = AF_NETGRAPH;
328 #ifdef ISO
329 			else if (strcmp(optarg, "iso") == 0)
330 				af = AF_ISO;
331 #endif
332 			else {
333 				errx(1, "%s: unknown address family", optarg);
334 			}
335 			break;
336 		case 'g':
337 			gflag = 1;
338 			break;
339 		case 'I': {
340 			char *cp;
341 
342 			iflag = 1;
343 			for (cp = interface = optarg; isalpha(*cp); cp++)
344 				continue;
345 			unit = atoi(cp);
346 			break;
347 		}
348 		case 'i':
349 			iflag = 1;
350 			break;
351 		case 'l':
352 			lflag = 1;
353 			break;
354 		case 'L':
355 			Lflag = 1;
356 			break;
357 		case 'M':
358 			memf = optarg;
359 			break;
360 		case 'm':
361 			mflag = 1;
362 			break;
363 		case 'N':
364 			nlistf = optarg;
365 			break;
366 		case 'n':
367 			nflag = 1;
368 			break;
369 		case 'p':
370 			if ((tp = name2protox(optarg)) == NULL) {
371 				errx(1,
372 				     "%s: unknown or uninstrumented protocol",
373 				     optarg);
374 			}
375 			pflag = 1;
376 			break;
377 		case 'r':
378 			rflag = 1;
379 			break;
380 		case 's':
381 			++sflag;
382 			break;
383 		case 't':
384 			tflag = 1;
385 			break;
386 		case 'u':
387 			af = AF_UNIX;
388 			break;
389 		case 'w':
390 			interval = atoi(optarg);
391 			iflag = 1;
392 			break;
393 		case '?':
394 		default:
395 			usage();
396 		}
397 	argv += optind;
398 	argc -= optind;
399 
400 #define	BACKWARD_COMPATIBILITY
401 #ifdef	BACKWARD_COMPATIBILITY
402 	if (*argv) {
403 		if (isdigit(**argv)) {
404 			interval = atoi(*argv);
405 			if (interval <= 0)
406 				usage();
407 			++argv;
408 			iflag = 1;
409 		}
410 		if (*argv) {
411 			nlistf = *argv;
412 			if (*++argv)
413 				memf = *argv;
414 		}
415 	}
416 #endif
417 
418 	/*
419 	 * Discard setgid privileges if not the running kernel so that bad
420 	 * guys can't print interesting stuff from kernel memory.
421 	 */
422 	if (nlistf != NULL || memf != NULL)
423 		setgid(getgid());
424 
425 	if (mflag) {
426 		mbpr();
427 		exit(0);
428 	}
429 	if (pflag) {
430 		if (iflag && tp->pr_istats) {
431 			kread(0, 0, 0);
432 			intpr(interval, nl[N_IFNET].n_value, tp->pr_istats);
433 			exit(0);
434 		}
435 		if (!tp->pr_stats) {
436 			printf("%s: no stats routine\n", tp->pr_name);
437 			exit(0);
438 		}
439 		if (tp->pr_usesysctl) {
440 			(*tp->pr_stats)(tp->pr_usesysctl, tp->pr_name);
441 		} else {
442 			kread(0, 0, 0);
443 			(*tp->pr_stats)(nl[tp->pr_sindex].n_value,
444 					tp->pr_name);
445 		}
446 		exit(0);
447 	}
448 #if 0
449 	/*
450 	 * Keep file descriptors open to avoid overhead
451 	 * of open/close on each call to get* routines.
452 	 */
453 	sethostent(1);
454 	setnetent(1);
455 #else
456 	/*
457 	 * This does not make sense any more with DNS being default over
458 	 * the files.  Doing a setXXXXent(1) causes a tcp connection to be
459 	 * used for the queries, which is slower.
460 	 */
461 #endif
462 	if (iflag) {
463 		if (af != AF_UNSPEC)
464 			goto protostat;
465 
466 		kread(0, 0, 0);
467 		intpr(interval, nl[N_IFNET].n_value, NULL);
468 		exit(0);
469 	}
470 	if (rflag) {
471 		kread(0, 0, 0);
472 		if (sflag)
473 			rt_stats(nl[N_RTSTAT].n_value);
474 		else
475 			routepr(nl[N_RTREE].n_value);
476 		exit(0);
477 	}
478 	if (gflag) {
479 		kread(0, 0, 0);
480 		if (sflag) {
481 			if (af == AF_INET || af == AF_UNSPEC)
482 				mrt_stats(nl[N_MRTSTAT].n_value);
483 #ifdef INET6
484 #ifdef notyet
485 			if (af == AF_INET6 || af == AF_UNSPEC)
486 				mrt6_stats(nl[N_MRT6STAT].n_value);
487 #endif
488 #endif
489 		} else {
490 			if (af == AF_INET || af == AF_UNSPEC)
491 				mroutepr(nl[N_MFCTABLE].n_value,
492 					 nl[N_VIFTABLE].n_value);
493 #ifdef INET6
494 #ifdef notyet
495 			if (af == AF_INET6 || af == AF_UNSPEC)
496 				mroute6pr(nl[N_MF6CTABLE].n_value,
497 					  nl[N_MIF6TABLE].n_value);
498 #endif
499 #endif
500 		}
501 		exit(0);
502 	}
503 
504   protostat:
505 	kread(0, 0, 0);
506 	if (af == AF_INET || af == AF_UNSPEC)
507 		for (tp = protox; tp->pr_name; tp++)
508 			printproto(tp, tp->pr_name);
509 #ifdef INET6
510 	if (af == AF_INET6 || af == AF_UNSPEC)
511 		for (tp = ip6protox; tp->pr_name; tp++)
512 			printproto(tp, tp->pr_name);
513 #endif /*INET6*/
514 	if (af == AF_IPX || af == AF_UNSPEC) {
515 		kread(0, 0, 0);
516 		for (tp = ipxprotox; tp->pr_name; tp++)
517 			printproto(tp, tp->pr_name);
518 	}
519 	if (af == AF_APPLETALK || af == AF_UNSPEC)
520 		for (tp = atalkprotox; tp->pr_name; tp++)
521 			printproto(tp, tp->pr_name);
522 	if (af == AF_NETGRAPH || af == AF_UNSPEC)
523 		for (tp = netgraphprotox; tp->pr_name; tp++)
524 			printproto(tp, tp->pr_name);
525 #ifdef NS
526 	if (af == AF_NS || af == AF_UNSPEC)
527 		for (tp = nsprotox; tp->pr_name; tp++)
528 			printproto(tp, tp->pr_name);
529 #endif
530 #ifdef ISO
531 	if (af == AF_ISO || af == AF_UNSPEC)
532 		for (tp = isoprotox; tp->pr_name; tp++)
533 			printproto(tp, tp->pr_name);
534 #endif
535 	if ((af == AF_UNIX || af == AF_UNSPEC) && !Lflag && !sflag)
536 		unixpr();
537 	exit(0);
538 }
539 
540 /*
541  * Print out protocol statistics or control blocks (per sflag).
542  * If the interface was not specifically requested, and the symbol
543  * is not in the namelist, ignore this one.
544  */
545 static void
546 printproto(tp, name)
547 	register struct protox *tp;
548 	char *name;
549 {
550 	void (*pr)();
551 	u_long off;
552 
553 	if (sflag) {
554 		if (iflag) {
555 			if (tp->pr_istats)
556 				intpr(interval, nl[N_IFNET].n_value,
557 				      tp->pr_istats);
558 			return;
559 		}
560 		else {
561 			pr = tp->pr_stats;
562 			off = tp->pr_usesysctl ? tp->pr_usesysctl
563 				: nl[tp->pr_sindex].n_value;
564 		}
565 	} else {
566 		pr = tp->pr_cblocks;
567 		off = tp->pr_usesysctl ? tp->pr_usesysctl
568 			: nl[tp->pr_index].n_value;
569 	}
570 	if (pr != NULL && (off || af != AF_UNSPEC))
571 		(*pr)(off, name, af);
572 }
573 
574 /*
575  * Read kernel memory, return 0 on success.
576  */
577 int
578 kread(addr, buf, size)
579 	u_long addr;
580 	char *buf;
581 	int size;
582 {
583 	if (kvmd == 0) {
584 		/*
585 		 * XXX.
586 		 */
587 		kvmd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, buf);
588 		if (kvmd != NULL) {
589 			if (kvm_nlist(kvmd, nl) < 0) {
590 				if(nlistf)
591 					errx(1, "%s: kvm_nlist: %s", nlistf,
592 					     kvm_geterr(kvmd));
593 				else
594 					errx(1, "kvm_nlist: %s", kvm_geterr(kvmd));
595 			}
596 
597 			if (nl[0].n_type == 0) {
598 				if(nlistf)
599 					errx(1, "%s: no namelist", nlistf);
600 				else
601 					errx(1, "no namelist");
602 			}
603 		} else {
604 			warnx("kvm not available");
605 			return(-1);
606 		}
607 	}
608 	if (!buf)
609 		return (0);
610 	if (kvm_read(kvmd, addr, buf, size) != size) {
611 		warnx("%s", kvm_geterr(kvmd));
612 		return (-1);
613 	}
614 	return (0);
615 }
616 
617 char *
618 plural(n)
619 	int n;
620 {
621 	return (n != 1 ? "s" : "");
622 }
623 
624 char *
625 plurales(n)
626 	int n;
627 {
628 	return (n != 1 ? "es" : "");
629 }
630 
631 /*
632  * Find the protox for the given "well-known" name.
633  */
634 static struct protox *
635 knownname(name)
636 	char *name;
637 {
638 	struct protox **tpp, *tp;
639 
640 	for (tpp = protoprotox; *tpp; tpp++)
641 		for (tp = *tpp; tp->pr_name; tp++)
642 			if (strcmp(tp->pr_name, name) == 0)
643 				return (tp);
644 	return (NULL);
645 }
646 
647 /*
648  * Find the protox corresponding to name.
649  */
650 static struct protox *
651 name2protox(name)
652 	char *name;
653 {
654 	struct protox *tp;
655 	char **alias;			/* alias from p->aliases */
656 	struct protoent *p;
657 
658 	/*
659 	 * Try to find the name in the list of "well-known" names. If that
660 	 * fails, check if name is an alias for an Internet protocol.
661 	 */
662 	if ((tp = knownname(name)) != NULL)
663 		return (tp);
664 
665 	setprotoent(1);			/* make protocol lookup cheaper */
666 	while ((p = getprotoent()) != NULL) {
667 		/* assert: name not same as p->name */
668 		for (alias = p->p_aliases; *alias; alias++)
669 			if (strcmp(name, *alias) == 0) {
670 				endprotoent();
671 				return (knownname(p->p_name));
672 			}
673 	}
674 	endprotoent();
675 	return (NULL);
676 }
677 
678 static void
679 usage()
680 {
681 	(void)fprintf(stderr, "%s\n%s\n%s\n%s\n",
682 "usage: netstat [-Aan] [-f address_family] [-M core] [-N system]",
683 "       netstat [-abdghimnrs] [-f address_family] [-M core] [-N system]",
684 "       netstat [-bdn] [-I interface] [-M core] [-N system] [-w wait]",
685 "       netstat [-M core] [-N system] [-p protocol]");
686 	exit(1);
687 }
688 
689 void
690 trimdomain(cp)
691 	char *cp;
692 {
693 	static char domain[MAXHOSTNAMELEN + 1];
694 	static int first = 1;
695 	char *s;
696 
697 	if (first) {
698 		first = 0;
699 		if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
700 		    (s = strchr(domain, '.')))
701 			(void) strcpy(domain, s + 1);
702 		else
703 			domain[0] = 0;
704 	}
705 
706 	if (domain[0]) {
707 		while ((cp = strchr(cp, '.'))) {
708 			if (!strcasecmp(cp + 1, domain)) {
709 				*cp = 0;	/* hit it */
710 				break;
711 			} else {
712 				cp++;
713 			}
714 		}
715 	}
716 }
717 
718